Systems and methods for esterifying lignin and lignin-alkanoate products

Abstract

Methods for esterifying lignin and producing a lignin-alkanoate product include steps of mixing lignin and a fatty acid derivative to form a first slurry; reacting the first slurry according to first reaction conditions to form a crude lignin-alkanoate; and extracting a lignin-alkanoate product from the crude lignin-alkanoate according to first extraction conditions. The methods can also include steps of mixing the crude lignin-alkanoate and alcohol to form a second slurry; reacting the second slurry according to second reaction conditions to form a crude alkyl lignin-alkanoate ester; and extracting an alkyl lignin-alkanoate ester product from the erode alkyl lignin-alkanoate ester according to second extraction conditions.

Description

Docket No. 333-003WOSYSTEMS A ND METH ODS FO R ESTE RIFYING LIGNIN AND LIGNIN-ALKANOA TE PRODUC TSC R O S S R E FEREN C E T O RELATED APP L IC A TIO N

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 718,889, filed on November 11, 2024, and entitled SYSTEMS AND METHODS FOR ESTERIFYING LIGNIN AND LIGNIN-ALKANOATE PRODUCTS, the contents of which is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates generally to lignin processing and, more particularly, to systems and methods for esterifying lignin and producing lignin- alkanoate products.B A C KG R O UND

[0003] There is an increasing interest in using biomass as a source for producing a variety of products, such as fuel, asphalt, and the like. Biomass is an organic material derived from living or recently living organisms, primarily plants. Biomass is considered carbon-neutral over its lifecycle, as the carbon dioxide released during its combustion or decomposition is roughly equivalent to the amount absorbed by the plants during their growth. This characteristic makes it a sustainable alternative to fossil fuels, contributing to reduced greenhouse gas emissions when managed sustainably.

[0004] Chemically, biomass includes carbon, hydrogen, and oxygen, with additional elements like nitrogen, sulfur, and trace minerals. The constituents of plant biomass include cellulose and hemicellulose, which are carbohydrate polymers that provide structural strength to plant cell walls. Plant biomass also includes lignin, which is a complex phenolic polymer that gives rigidity to plant cell walls and makes them resistant to degradation and mechanical stress. Lignin is one of the most abundant biopolymers on Earth, alongside cellulose and hemicellulose. However, the complexity of lignin’s structure makes it challenging to break down, presenting challenges for industries that seek to depolymerize lignin into useful byproducts.Docket No. 333-003WO

[0005] Accordingly, those skilled in the art continue with research and development efforts in the field of lignin processing.S U MM A RY

[0006] Disclosed are examples of a method for esterifying lignin, a method for direct esterification of lignin, a method for transesterification of lignin, a method for producing a lignin-alkanoate, a method for producing an alkyl lignin-alkanoate product, a lignin-alkanoate product, and a system for esterifying lignin. The following is a non-exhaustive list of examples, which may or may not be claimed, of the subject matter according to the present disclosure.

[0007] In an example, the disclosed method includes steps of: (1) mixing lignin and a fatty acid derivative to form a first slurry; (2) reacting the first slurry according to first reaction conditions to form a crude lignin-alkanoate; and (3) extracting a lignin-alkanoate product from the crude lignin-alkanoate according to first extraction conditions.

[0008] In an example, the disclosed method includes steps of: (1) mixing lignin and a fatty acid derivative to form a first slurry; (2) reacting the first slurry according to first reaction conditions to form a crude lignin-alkanoate; (3) mixing the crude lignin-alkanoate and alcohol to form a second slurry; (4) reacting the second slurry according to second reaction conditions to form a crude alkyl lignin-alkanoate ester; and (5) extracting an alkyl lignin-alkanoate ester product from the crude alkyl lignin-alkanoate ester according to second extraction conditions.

[0009] In an example, the disclosed method includes steps of: (1) providing a fatty acid derivative (e.g„ liquid fatty acid or liquid fatty acid ester); (2) mixing lignin with the fatty acid derivative; (3) forming a first slurry that includes the fatty acid derivative, the lignin, and water;(4) heating the first slurry to a first temperature of between approximately 80°C and approximately 200°C; (5) holding the first slurry at the first temperature; (6) removing the water from the first slurry; (7) forming a second slurry that includes the fatty acid derivative and the lignin; (8) mixing a catalyst to the second slurry; (9) forming a first reaction mixture that includes the fatty acid derivative, the lignin, and the catalyst; (10) mixing the first reaction mixture; (11) heating the first reaction mixture to a second (e.g., reaction) temperature of between approximately 130°C and approximately 250°C; (12) holding the first reaction mixtureDocket No. 333-003WO at the second temperature (e.g., reaction temperature in the aforementioned range); (13) removing a vapor byproduct from the first reaction mixture; and (14) forming a first product mixture that includes a lignin-alkanoate and the catalyst.

[0010] In an example, the disclosed method includes steps of: (1) forming a first slurry that includes a fatty acid derivative, lignin, and water; (2) removing the water from the first slurry to form a first reaction mixture that includes the fatty acid derivative, the lignin, and a catalyst; (3) heating the first reaction mixture to remove a vapor byproduct from the first reaction mixture and to form a first product mixture that includes a lignin-alkanoate and the catalyst.

[0011] In an example, the disclosed method includes steps of: (1) forming a first slurry that includes a liquid fatty acid derivative, lignin, and water; (2) forming a first reaction mixture that includes the fatty acid derivative, the lignin, and a catalyst; (3) forming a first product mixture that includes a lignin-alkanoate, unreacted fatty acid derivative, and the catalyst; (4) forming an extraction mixture that includes the lignin reaction product and any unreacted fatty acid derivative, an aqueous solution of the catalyst and wash water; (5) forming an organic-rich raffinate phase that includes the lignin-alkanoate and trace water and a separate aqueous extract phase containing the catalyst and residual salts from the lignin precursor; and (6) producing the lignin-alkanoate. An extraction process removes the acid and any salts that were trapped in the original lignin feedstock. The removal of these salts is potentially useful for making a fuel product. For example, lignin feedstock from Kraft processing contains residual salt species (e.g., sodium salt species).

[0012] In an example, the disclosed method includes steps of: (1) forming a first slurry that includes a fatty acid derivative, lignin, and water; (2) forming a first reaction mixture that includes the fatty acid derivative, the lignin, and a catalyst; (3) forming a first product mixture that includes a lignin-alkanoate and the catalyst; (4) forming a second reaction mixture that includes the lignin-alkanoate , the catalyst, an alcohol, and a water byproduct; (5) forming a second product mixture that includes an alkyl lignin-alkanoate ester and the catalyst; (6) forming an extraction mixture that includes the alkyl lignin-alkanoate ester, the catalyst and wash water; (7) forming an organic-rich raffinate phase that includes the alkyl lignin-alkanoate ester and aDocket No. 333-003WO separate aqueous extract phase that contains acid, salts, and residual water; and (8) producing the alkyl lignin-alkanoate ester product.

[0013] In an example, the disclosed lignin-alkanoate product is made according to the methods.

[0014] In an example, the disclosed a lignin-alkanoate product includes a lignin polymer on which hydroxyl functionalities have been reacted with a fatty acid to form ester bonds and on which the carboxyl functionalities of the organic acid have been reacted with hydroxyl functionalities of the lignin to form ester bonds.

[0015] In an example, the disclosed alkyl lignin-alkanoate product includes a lignin-alkanoate polymer on which acid functionalities have been reacted with an alcohol to form ester bonds and on which the carboxyl functionalities of the lignin have been reacted with hydroxyl functionalities of the alcohol to form ester bonds.

[0016] In an example, the system includes components configured for implementing the methods.

[0017] Other examples of the esterification methods, lignin-alkanoate products, and the systems will become apparent from the following detailed description, the accompanying drawings, and the appended claims.B RIEF D E S C RIP TI O N O F TH E DRAWING S

[0018] Fig. 1 is an illustration of an example of a lignin-alkanoate product (“LFA”);

[0019] Fig. 2 is an illustration of an alkyl lignin-alkanoate ester product (“LFAA”);

[0020] Figs. 3A-3C, collectively also referred to as Fig. 3, is a flow diagram of an example of a method for esterifying lignin and producing lignin-alkanoate products;

[0021] Figs. 4A-4C, collectively also referred to as Fig. 4, is a flow diagram of an example of the method for esterifying lignin and producing lignin-alkanoate products;

[0022] Fig. 5 is a schematic illustration of an example of a system for esterifying lignin and producing lignin-alkanoate products;Docket No. 333-003WO

[0023] Fig. 6 is a schematic illustration of an example of an integrated system and method for producing lignin- alkanoate products;

[0024] Fig. 7 is a schematic illustration of an example of a system and method for treating black liquor and producing solid lignin;

[0025] Fig. 8 is a schematic illustration of an example of the system and method for treating lignin and producing solid lignin integrated into a pulp mill operation;

[0026] Fig. 9 is an illustration of examples reactions of carboxylic acids and esters with water and alkoxides; and

[0027] Figs. 10-12 are charts illustrating analysis results of modified-lignin products.D ETAILED D E S C RIPTI O N

[0028] The present disclosure recognizes that U.S. kraft wood pulp industry burns about 40 million metric tons (Te) per year of lignin in the industry’s recovery boilers. These boilers recover sodium and sulfur, which are ultimately remade into necessary pulping reagents, and generate high-pressure steam, which is partially used for electrical power generation. The generated electrical power is used at the mill, and any excess is sold to power companies for further distribution. Currently, less than 0.1% of the kraft lignin in the U.S. is recovered as a solid and sold or used in material or fuel applications. If lignin could be converted to a liquid form that does not readily retain water, the market opportunities would dramatically increase and include a precursor for biofuels, such as sustainable aviation fuel, additives for molten asphalt, and binders for wood and carbon pellets. Technologies to achieve this goal are currently being commercialized at two companies in Sweden - Ren Fuel K2B AB and Lignin Industries AB. These technologies increase the hydrophobicity of lignin by reacting it with fatty acids that are low-melting (less than 100 °C) solids or liquids at ambient conditions. However, both processes are relatively complex, involve moisture-sensitive reagents, and are high-cost. Thus, a low-cost, robust method for reacting lignin with fatty acids and / or bio-derived alcohols is needed to increase the hydrophobicity of lignin, thereby creating a renewable feedstock material for a variety of fuel and material products.Docket No. 333-003WO

[0029] Referring now to Figs. 1-12, by way of examples, the present disclosure is directed to a methods and a systems for processing lignin and, more particularly, methods and systems for esterifying lignin and producing lignin-alkanoate products (e.g„ lignin-alkanoate products 100 shown in Figs. 1 and 2). Examples of the disclosed methods include a number of elements, steps, operations, or processes. Not all of the elements, steps, operations, or processes described or illustrated in one example are required in that example. Some or all of the elements, steps, operations, or processes described or illustrated in one example can be combined with other examples in various ways without the need to include other elements, steps, operations, or processes described in those other examples, even though such combination or combinations are not explicitly described or illustrated by example herein.

[0030] Referring to Figs. 1 and 2, by way of examples, the present disclosure is directed to lignin-alkanoate product 100 produced according to the disclosed methods and / or using the disclosed systems. As illustrated in Fig. 1 , in one or more examples, lignin 120 reacts with fatty acid derivative 110 (e.g., fatty acid 112 or fatty acid ester 114) to make or produce lignin- alkanoate 102. As illustrated in Fig. 2, in one or more examples, lignin-alkanoate 102 reacts with alcohol 116 to make or produce alkyl lignin-alkanoate ester 104.

[0031] Lignin is a complex, high-molecular- weight, irregular polymer found in the cell walls of plants, particularly in wood and bark. Chemically, lignin includes phenylpropanoid units linked by various carbon-carbon and ether bonds, forming a three-dimensional, highly branched network. Generally, lignin is a solid, brown powder at room temperature. Lignin is insoluble in most solvents. In industrial applications, lignin is often dried to a low moisture content to improve storage stability and make the dry lignin more suitable for applications. The moisture content of dry lignin typically ranges from less than one (1) percent to approximately eight (8) percent under normal conditions. However, dry lignin has explosivity indices similar to those of sugar. Additionally, when exposed to humidity, lignin quickly absorbs moisture until it reaches its equilibrium moisture content of about 15%. As such, processing of dry lignin requires carefully controlled processes.

[0032] The present disclosure recognizes the desire to process lignin for derivative uses, such as biofuels, bioplastics, biochemicals, additives, binders, and the like. The present disclosure alsoDocket No. 333-003WO recognizes that lignin processing is challenging and expensive. Some current lignin processing methods utilize complex and expensive chemical processes for reacting lignin with fatty acid at low lignin-to-fatty acid ratios to produce a liquid that is soluble in light gas oil. Other lignin processing methods utilize complex and expensive vented extruders to react lignin with fatty acid at high lignin-to-fatty acid ratios to produce solid pellets. In addition to the cost and complexity of the existing solutions, these lignin processing methods have further limitations in the use and desirability of the processed lignin end product.

[0033] Examples of the methods and systems disclosed herein address many of the disadvantages existing in the field and expressed above. Examples of the methods and systems disclosed herein facilitate significant reductions in the cost and complexity of lignin processing. Examples of the methods and systems disclosed herein advantageously enable transformation of solid lignin into liquid lignin. Examples of the methods and systems disclosed herein advantageously enable integration with pulp milling processes to increase capacity and lower processing costs.

[0034] In one or more examples, implementations of the methods include a series of catalyzed reactions, for example using a water-soluble catalyst, such as an acid catalyst or a base catalyst. In one or more examples, implementations of the methods include a series of acid-catalyzed reactions involving lignin and a species of a fatty acid derivative, such as a fatty acid or a fattyacid ester, to produce a lignin- alkanoate product, as expressed below (in equations 1A, IB and 2).

[0035] In one or more examples, a first reaction includes lignin transesterification with a fatty acid ester (e.g., biodiesel, H2SO4 acid catalyzed) to make a lignin-alkanoate and an alcohol species (expressed by equation 1A below).

[0036] Lignin-OH + FA-COOCH3 Lignin-OOC-FA + HOCH3 (Eq. 1A)

[0037] For the purpose of the present disclosure, the term “fatty acid ester” can be used interchangeably with the term “alkanoate.”Docket No. 333-003WO

[0038] In one or more examples, (e.g., alternatively) the first reaction includes esterification of hydroxyl groups on the lignin with a fatty acid species (H2SO4 acid catalyzed) to make a lignin- alkanoate and water (expressed by equation IB below).

[0039] Lignin-OH + FA-COOH Lignin-OOC-FA + HOH (Eq. IB)

[0040] Following the reaction shown in Eq. IB, unreacted carboxylic acid groups remain on the lignin polymer. In one or more examples, a second reaction includes esterification of carboxylic acid groups on modified lignin (e.g., lignin-alkanoate) with an alkyl alcohol species (H2SO4 acid catalyzed) to make an alkyl lignin-alkanoate ester and water (expressed by equation 2 below).

[0041] FA-COO-Lignin-COOH + Alk-OH FA-COO-Lignin-COO-Alk + HOH (Eq. 2)

[0042] Accordingly, as illustrated in Figs. 1 and 2, depending on the reactions, examples of the methods disclosed herein produce lignin-alkanoate product 100. Lignin-alkanoate product 100 can also be referred to as a lignin ester or a lignin-ester product. In one or more examples, lignin- alkanoate product 100 takes the form of lignin-alkanoate 102 (e.g., as shown in Fig. 1), which is produced according to one of the first reactions (e.g., equation 1A or equation IB). In one or more examples, lignin-alkanoate product 100 takes the form of alkyl lignin-alkanoate ester 104 (e.g., as shown in Fig. 2), which is produced according to the second reaction (e.g., equation 2).

[0043] Throughout the present disclosure, lignin-alkanoate 102 may be also referred to as “LFA” (e.g., Fig. 1) or as an LFA product. In one or more examples, LFA 102 is a lignin polymer in which the hydroxyl functionalities have been reacted with fatty acids to form ester bonds. As illustrated in Fig. 1, in one or more examples, LFA product 102 results from a lignin polymer (e.g., lignin 120) having its hydroxyl groups reacted with the carboxyl group of fatty acids to form ester groups. The lignin polymer and the lignin-alkanoate product also have carboxyl groups.

[0044] Throughout the present disclosure, alkyl lignin-alkanoate ester 104 may also be referred to as “LFAA” (e.g., Fig. 2) or as an LFAA product. In one or more examples, LFAA 104 is a lignin polymer on which the hydroxyl functionalities have been reacted with fatty acids to form ester bonds and on which the carboxyl functionalities have been reacted with alcohols to formDocket No. 333-003WO ester bonds. As illustrated in Fig. 2, in one or more examples, alkyl lignin-alkanoate ester 104 (LFAA) includes lignin-alkanoate 102 (LFA) that is then reacted with an alcohol. As illustrated in Fig. 2, in these examples, an alcohol (e.g., a moderate to high molecular weight alcohol or a low-volatility alcohol) reacts with the carboxyl groups of LFA 102 to form LFAA 104. Advantageously, in some implementations of the disclosed methods, LFAA 104 is more likely to be a liquid at room temperature than LFA 102, and LFAA 104 is likely to be more soluble in non-polar organic solvents (e.g., petroleum distillates) than LFA 102. In one or more examples, LFAA 104 is LFA 102 in which the carboxyls of the lignin polymer react with the hydroxyls of a higher-molecular-weight (or low volatility) alcohols. In one or more examples, LFAA 104 has carboxyl groups reacted with the hydroxyl groups of alcohols to form more ester groups.

[0045] In one or more examples, for each 1000 molecular weight (MW) units of the lignin polymer, there will be approximately four hydroxyl and one carboxyl groups. In these examples, LFAA 104 will have approximately 5 / 4 times more ester groups than LFA 102. In one or more examples, a significant portion, but possibly not all, of the lignin alcohol and carboxyl groups will react to form ester groups (e.g., the reaction conversions for the lignin alcohol and carboxyl groups into ester groups is not 100% or the reaction conversions for reactions shown in Figs. 1 and 2 may not be 100%).

[0046] Carboxyl groups have a proton that “floats” within the electron cloud of the two oxygen molecules. Notoriously, carboxyl groups want to dimerize other carboxyl groups forming two hydrogen-bonds between the two groups. In this manner, two carboxyl groups on adjacent lignin polymers can form two hydrogen-bonds, which in effect creates a higher MW polymer that is more likely to be a solid. Reacting these lignin carboxyl groups with an alcohol, making the lignin product, will negate this hydrogen-bonding between lignin polymers, which will effectively reduce the molecular weight of a given lignin species (e.g., lignin agglomeration or association of molecules) and make it more likely that those species will exist as a liquid at ambient conditions. In one or more examples, the bonding between carboxyls group is hydrogen bonding not ionic bonding. In one or more examples, a carboxyl group can form hydrogen bonds with another carboxyl group by acting as both a hydrogen bond donor (via its hydroxyl hydrogen) and acceptor (via the carbonyl oxygen).Docket No. 333-003WO

[0047] While not being bound by any specific scientific theory, it is believed that LFAA 104 can be synthesized by reacting lignin first with an alcohol to form esters with the carboxyl groups of the lignin. As an example, while not being bound by any specific scientific theory, it is believed that the reactions expressed herein above may be performed in an opposite order. In other words, in one or more examples, the carboxylic groups on the lignin moieties can react first, and then the alcohol groups on the lignin reacted. Accordingly, in one or more examples, implementations of the methods include a series of acid-catalyzed reactions involving lignin and a fatty acid, as expressed below (in equations 3, 4A and 4B).

[0048] In one or more examples, a third reaction includes esterification of the carboxylic acid groups on the lignin with an alkyl alcohol species (H2SO4 acid catalyzed) to make an alkyl lignin ester and water (expressed by equation 3 below).

[0049] Lignin-COOH + FA-OH Lignin-COO-FA + HOH (Eq. 3)

[0050] In one or more examples, a fourth reaction includes transesterification of the hydroxyl groups on the alkyl-lignin ester with a fatty acid ester (e.g., biodiesel, H2SO4 acid catalyzed) to make an alkyl-lignin ester alkanoate and an alcohol species (expressed by equation 4A below).

[0051] Lignin-OH + FA-COOCH3 Lignin-OOC-FA + HOCH3 (Eq. 4A)

[0052] In one or more examples, (e.g., alternative) the fourth reaction includes esterification of the hydroxyl groups on lignin with a fatty acid species (H2SO4 acid catalyzed) to make an alkyl- lignin ester alkanoate and water (expressed by equation 4B below).

[0053] Lignin-OH + FA-COOH Lignin-OOC-FA + HOH (Eq. 4B)

[0054] Accordingly, depending on the reactions, examples of the methods disclosed herein produce the lignin-alkanoate product. In one or more examples, the lignin-alkanoate product takes the form of alkyl lignin ester (e.g., an alkyl lignin ester product), which is produced according to the third reaction (equation 3). In one or more examples, the lignin-alkanoate product takes the form of an alkyl-lignin ester alkanoate (e.g., an alkyl-lignin ester alkanoate product), which is produced according to the fourth reaction (equation 4A or equation 4B).Docket No. 333-003WO

[0055] In one or more examples, LFA 102, made or produced by reacting lignin (e.g., solid lignin 120) with fatty acid derivative 110 (e.g., fatty acid 112 or fatty acid ester 114), may exist as a liquid or solid depending on the MW of the LFA product and / or the reaction conditions used to produce LFA 102. In certain examples, LFA 102 is a solid at ambient conditions. In certain cases, LFA 102 is soluble in hydrocarbons at warm temperatures. In one or more examples, reacting LFA 102 with a non-volatile alcohol (e.g., C12 lauryl alcohol) makes or produces LFAA 104. LFAA 104 may exist as a liquid or solid at ambient conditions depending on the MW of the LFAA product and / or the reaction conditions used to produce LFAA 104. In certain cases, LFAA 104 is more soluble in hydrocarbon solvents. LFA 102 and LFAA 104 are promising for a number of high-volume applications including biofuels and asphalt. In various examples, oleic acid can be used for the fatty acid derivative (e.g.. fatty acid 112) and butanol can be used as the alcohol (e.g., alcohol 116). In one or more examples, stoichiometrically, for each 1000 MW units of a lignin polymer, four fatty acids can be reacted to form LFA 102 and then one alcohol can be reacted with LFA 102 to make LFAA 104.

[0056] While not being bound by any specific scientific theory, it is believed that LFAA 104 is more likely to be a liquid at ambient conditions and more soluble in hydrocarbon solvents than LFA 102. After reacting lignin with fatty acid, the LFA polymer will have residual carboxylic groups as shown in Fig. 1. On average, lignin will have about four hydroxyl groups and one carboxylic group for every 1000 molecular weight units of the lignin. Fig. 1 shows all four hydroxyl groups of the lignin, each one reacted with a fatty acid to form the LFA polymer. It is further believed that the hydrogen atoms on each carboxylic acid is free to associate with another carboxylic acid group on an adjacent lignin polymer forming two hydrogen bonds. In one or more examples, a carboxyl group can form hydrogen bonds with another carboxyl group by acting as both a hydrogen bond donor (via its hydroxyl hydrogen) and acceptor (via the carbonyl oxygen). Two separate lignin polymers can hydrogen bond with each other through their carboxylic groups. Multiple LFA polymers can be strongly linked through these hydrogen bonded carboxylic groups, increasing the effective molecular weight of the LFA polymer and increasing the temperature where they become a solid upon cooling, i.e., increasing their “freezing point.” Reacting the carboxyls on the lignin with an alcohol (e.g.. high MW alcohol) after completion of the LFA reaction will lessen the intramolecular and intermolecular hydrogenDocket No. 333-003WO bonding between separate lignin carboxyl moieties and allow the lignin molecules to “relax” and become more fluid-like.

[0057] As will be described in more detail herein, examples of the methods and systems disclosed herein advantageously provide a simple and cost-effective process. In one or more examples, the methods and systems utilize a batch reactor at low pressure (e.g., between 0.1 atm and 2 atm or atmospheric pressure) and / or moderate reaction temperatures (e.g., between approximately 80°C and 200°C, such as approximately 170°C). The use of low volatility reagents, including lignin, fatty acids, and low-volatility alcohols, enables the reactor to be operated at atmospheric conditions without a significant volatilization or loss of these species. The use of lower MW acids or alcohols, having a higher volatility would not allow for the use of elevated reaction temperatures at low pressures because the low MW species would readily vaporize and be unavailable to react with the lignin hydroxyl or carboxyl groups. Operating at these low pressures offers many advantages. The advantages include less expensive reactor vessels and pumps, inherently safer operating conditions, and significantly, the ready removal of reaction byproducts, such as water and low molecular weight alcohols (the latter formed when biodiesel is used in reaction. The removal of these reaction byproducts increases the formation of lignin ester products (LFA 102 and LFAA 104) as they are formed by a revisable esterification or transesterification reaction. The use of low volatility reactants, including acetic acid, methanol, ethanol and propanol, would require the use of high-pressure reactors. In one or more examples, the methods and systems utilize an inexpensive and easy to procure acidic catalyst (e.g., sulfuric acid). In one or more examples, the methods and systems are efficient, for example, one ton of lignin can produce 2.06 tons of LFA 102 or 2.11 tons of LFAA 104.

[0058] Referring now to Figs. 3A-3C, which illustrate an example of method 2000 for esterifying lignin and producing lignin-alkanoate products (e.g., lignin-alkanoate product 100). Generally, method 2000 facilitates the conversion of black liquor into various forms of modified lignin products through a series of processing stages, reaction processes, and extraction processes. Method 2000 may also be referred to as an esterification method. In one or more examples, the method 2000 is implemented using system 200 (Fig. 5). In one or more examples, method 2000 is used to produce the LFA 102 (e.g., lignin-alkanoate product) (e.g., as shown in Fig. 1) and / or the LFAA 104 (alkyl lignin-alkanoate ester product) (e.g., as shown in Fig. 2).Docket No. 333-003WO

[0059] In one or more examples, at block 2002, method 2000 includes a step of providing black liquor 302. In one or more examples, black liquor 302 is a byproduct of a kraft pulping process performed at a pulp mill. In one or more examples, at block 2004, black liquor 302 is processed through recovery process to produce wet lignin 126, at block 2006, or moist lignin 122, at block 2008. In one or more examples, Sequential Liquid-Lignin Recovery and Purification (SLRP) (often abbreviated SLRP) or similar processes are used for recovering lignin from black liquor.

[0060] In one or more examples, at block 2010, wet lignin 126 or moist lignin 122 are processed through a drying process to produce dry lignin 128, at block 2014. In one or more examples, dry lignin 128 has a moisture content of between approximately one percent (1%) and twenty percent (20%) water by weight. The drying process removes water from wet lignin 126 or moist lignin 122 to achieve the desired moisture content range for subsequent reaction processes.

[0061] In one or more examples, following the drying process, method 2000 branches into two optional reaction pathways: an LFA reaction process and an LFAA reaction process.

[0062] In one or more example, in the LFA reaction process, fatty acid derivative 110 is provided, at block 2016. At block 2018, dry lignin 128 is combined with fatty acid derivative 110 and the mixture undergoes the LFA reaction process. In one or more examples, fatty acid derivative 110 includes fatty acid 112 or fatty acid ester 114.

[0063] In one or more examples, the LFA reaction process operates under LFA reaction conditions 252, which include temperature 256, pressure 258, time 260. and catalyst 140. In one or more examples, temperature 256 is between approximately 80°C and approximately 200°C, such as between approximately 100°C and approximately 120°C. In one or more examples, pressure 258 is between approximately 0.1 atm and approximately 2 atm. In one or more examples, time 260 is between approximately 2 hours and approximately 10 hours. In one or more examples, catalyst 140 includes water-soluble catalyst 141. In one or more examples, catalyst 140 includes acid catalyst 142 or a base catalyst 144. In one or more examples, catalyst 140 is present in an amount of between approximately 0.1% and approximately 2% by weight relative to the mixture (or to dry lignin 128).Docket No. 333-003WO

[0064] At block 2020, the LFA reaction process produces crude LFA 202. Crude LFA 202 can exist in different physical forms depending on the reaction conditions and subsequent processing. In one or more examples, crude LFA 202 includes or takes the form of liquid crude LFA 262 and / or solid crude LFA 264. Liquid crude LFA 262 and solid crude LFA 264 are directed to different extraction processes based on their physical state.

[0065] In one or more examples, at block 2022, liquid LFA 262 is processed through a liquidliquid extraction process. The liquid-liquid extraction process operates under liquid extraction conditions 272, which include temperature 256, pressure 258, and solvent 276. In one or more examples, temperature 256 for liquid extraction conditions 272 is between approximately 25 °C and approximately 150°C. In one or more examples, pressure 258 for liquid extraction conditions 272 is between approximately 1 atm and approximately 5 atm. In one or more examples, solvent 276 includes or takes the form of water. In one or more examples, the liquid-liquid extraction process operates at an elevated temperature and pressure sufficient to maintain crude LFA 202 in liquid form during the extraction process. The liquid-liquid extraction process produces liquid LFA product 282, at block 2024.

[0066] In one or more example, at block 2034, solid crude LFA 264 is processed through a solid-liquid extraction process. The solid-liquid extraction process operates under solid extraction conditions 274, which include temperature 256, pressure 258, and solvent 276. In one or more examples, temperature 256 for solid extraction conditions 274 is between approximately 25°C and approximately 150°C. In one or more examples, pressure 258 for solid extraction conditions 274 is between approximately 1 atm and approximately 5 atm. In one or more examples, solvent 276 includes or takes the form of water. The solid-liquid extraction process produces solid LFA product 284, at step 2026.

[0067] In one or more example, in the LFAA reaction process, alcohol 116 is provided, at block 2028. At block 2030, crude LFA 202 is combined with alcohol 116 and the mixture undergoes the LFAA reaction process. In one or more examples, alcohol 116 includes a C4 to Ci6 linear alcohol. In one or more examples, alcohol 116 includes a low- volatility alcohol or a high molecular weight alcohol.Docket No. 333-003WO

[0068] In one or more examples, the LFAA reaction process operates under LFAA reaction conditions 254, which include temperature 256, pressure 258, time 260, and catalyst 140. In one or more examples, temperature 256 is between approximately 80°C and approximately 200°C. In one or more examples, pressure 258 is between approximately 0.1 atm and approximately 2 atm. In one or more examples, time 260 is between approximately 2 hours and approximately 10 hours. In one or more examples, catalyst 140 includes a water-soluble catalyst 141. In one or more examples, catalyst 140 includes acid catalyst 142 or a base catalyst 144. In one or more examples, catalyst 140 is present in an amount of between approximately 0.1% and approximately 2% by weight relative to the mixture (or crude LFA 202).

[0069] At block 2032, the LFAA reaction process produces crude LFAA 204. Crude LFAA 204 can exist in different physical forms depending on the reaction conditions and subsequent processing. In one or more examples, crude LFAA 204 includes or takes the form of liquid crude LFAA 266 and / or solid crude LFAA 268. Liquid crude LFAA 266 and solid crude LFAA 268 are directed to different extraction processes based on their physical state.

[0070] In one or more examples, at block 2022, liquid crude LFAA 266 is processed through the liquid-liquid extraction process. The liquid-liquid extraction process operates under liquid extraction conditions 272, for example, as previously described. The liquid-liquid extraction process produces liquid LFAA product 286, at block 2036.

[0071] In one or more examples, at block 2034, solid crude LFAA 268 is processed through the solid-liquid extraction process. The solid-liquid extraction process operates under solid extraction conditions 274, for example, as previously described. The solid-liquid extraction process produces solid LFAA product 288, at block 2038.

[0072] In one or more examples, the liquid-liquid extraction process and the solid-liquid extraction process remove catalyst 140 and any residual inorganic salts from crude LFA 202 or crude LFAA 204. In one or more examples, the extraction processes produce final products having low ash content and being substantially free of catalyst 140. In one or more examples, liquid LFA product 282, solid LFA product 284, liquid LFAA product 286, and solid LFAA product 288 have an ash content of less than approximately 1% by weight and are substantially free of catalyst 140.Docket No. 333-003WO

[0073] In one or more examples, the final lignin-alkanoate products are cooled to a desired temperature and stored in storage tanks for subsequent use or transportation to customers.

[0074] The examples of method 2000 illustrate a flexible and efficient process producing multiple forms of lignin-alkanoate products from black liquor feedstock. The different reaction pathways enable production of LFA and LFAA products, while alternative extraction processes accommodate both liquid and solid final product forms. In various examples, the process operates at low pressure (e.g., between approximately 0.1 atm and approximately 2 atm) and moderate temperatures (between approximately 80°C and approximately 200°C), providing cost- effective and safe processing conditions. The use of water-soluble catalysts facilitates efficient removal of the catalyst through water extraction, producing high-purity final products suitable for various applications including biofuels, asphalt additives, and binders.

[0075] Referring now to Figs. 4A-4C, also referred to hereinafter collectively as Fig. 4, the following are which illustrate examples of method 1000 for esterifying lignin and producing lignin-alkanoate products (e.g., lignin-alkanoate product 100). Generally, method 1000 facilitates the conversion of black liquor into various forms of modified lignin products through a series of processing stages, reaction processes, and extraction processes. Method 1000 may also be referred to as an esterification method. In one or more examples, the method 1000 is implemented using the system 200 (Fig. 5). In one or more examples, the method 1000 is used to produce the LFA 102 (e.g., lignin-alkanoate product) (e.g.. as shown in Fig. 1) and / or the LFAA 104 (alkyl lignin-alkanoate ester product) (e.g., as shown in Fig. 2). In one or more examples, method 1000 is an example implementation of method 2000 (e.g., as shown in Fig. 3).

[0076] In one or more examples, implementation of method 1000 includes performing the first reaction (Equation 1A) and the second reaction (Equation 2) in order to achieve transesterification with biodiesel followed by esterification using an alcohol.

[0077] In one or more examples, implementation of method 1000 includes performing the first reaction (Equation IB) and the second reaction (Equation 2) in order to achieve esterification with a fatty acid followed by esterification using an alcohol.Docket No. 333-003WO

[0078] As illustrated in Figs. 4A, in one or more examples, at block 1002, method 1000 includes a step of providing fatty acid derivative 110. In various examples, fatty acid derivative refers to a compound that contains or is derived from a fatty acyl group (R-CO-) having a hydrocarbon chain of typically 4 to 24 carbon atoms. In various examples, the fatty acid derivative includes, without limitation, free fatty acids and fatty acid esters, including methyl, ethyl, and glycerol esters such as those present in biodiesel compositions. Unless otherwise indicated, the fatty acid derivative excludes fatty acid salts, amides, halides, anhydrides, peroxides, or other oxidized or nitrogen-containing derivatives.

[0079] In one or more examples, fatty acid derivative 110 includes or takes the form of fatty acid 112. In one or more examples, fatty acid derivative includes or takes the form of fatty acid ester 114.

[0080] In one or more examples, fatty acid 110 includes a C4 to Cis fatty acid (e.g., fatty acid 110 includes a saturated or unsaturated fatty acid having a carbon chain length of between 4 and 16 carbon atoms.) In one or more examples, fatty acid 110 is an unsaturated fatty acid having one or more olefinic bonds. In one or more examples, fatty acid 110 is a monounsaturated fatty acid having a single olefinic bond. In one or more examples, fatty acid 110 is a polyunsaturated fatty acid having multiple olefinic bonds. In one or more examples, fatty acid 110 includes oleic acid, palmitoleic acid, linoleic acid, alpha-linolenic acid, arachidonic acid, docosahexaenoic acid, or combinations thereof. In one or more examples, fatty acid 110 includes tall oil or a tall oil derivative. In one or more examples, fatty acid 110 fatty acid mixtures derived from soybean oil, corn oil, sunflower oil, or palm oil. In one or more examples, fatty acid 110 includes crude tall oil from a kraft pulp mill, wherein the fatty acid content may be approximately 50% of the total composition.

[0081] In one or more examples, fatty acid ester 114 includes biodiesel. In one or more examples, fatty acid ester 114 includes a fatty acid methyl ester. In one or more examples, fatty acid ester 114 includes methyl oleate, methyl palmitate, methyl stearate, methyl linoleate, or methyl linolenate. In one or more examples, fatty acid ester 114 includes a mixture of fatty acid methyl esters derived from vegetable oils or animal fats. In one or more examples, fatty acid ester 114 includes fatty acid methyl esters derived from soybean oil, com oil, sunflower oil.Docket No. 333-003WO safflower oil, rapeseed oil, palm oil, or yellow grease. Tn one or more examples, fatty acid ester 114 includes soybean oil-based biodiesel, which contains multiple fatty acid esters of differing molecular weight and varying degrees of unsaturation. In one or more examples, fatty acid ester 114 includes com oil-based biodiesel, which contains approximately 13% saturated fatty acid esters, approximately 28% monounsaturated fatty acid esters, and approximately 59% polyunsaturated fatty acid esters. In one or more examples, fatty acid ester 114 includes a C4 to Cis fatty acid ester. In one or more examples, the fatty acid ester 114 is a liquid at room temperature or at moderately elevated temperatures.

[0082] In one or more examples, fatty acid derivative 110 is a liquid at room or moderately elevated temperatures. In various examples, fatty acid derivative 110 can include any suitable liquid that contains a fatty acid or fatty acid mixture. In one or more examples, fatty acid derivative 110 is charged or loaded into a batch reactor 210 (Fig. 5). In one or more examples, most fatty acids formed in nature exist as a mixture of fatty acids of differing MW and number of unsaturated (or olefinic) bonds. Common sources of fatty acids, and the composition of the systems, include soybean oil-based biodiesel contains multiple fatty acid esters of differing MW.

[0083] In one or more examples, fatty acid derivative 110 includes or takes the form of a liquid fatty acid (e.g.. fatty acid 112 in a liquid state). In these examples, method 1000 may also be referred to as a direct esterification method. In examples in which fatty acids 112 are used as the fatty acid derivative 110 and are used as the reactant, method 1000 may also be referred to a direct esterification reaction or the direct esterification method.

[0084] In one or more examples, fatty acid derivative 110 includes or takes the form of a liquid fatty acid ester (e.g., fatty acid ester 114 in a liquid state). In these examples, method 1000 may also be referred to as a transesterification method. In examples in which biodiesel is used as fatty acid derivative 110 (e.g., fatty acid ester 114) and is used as the reactant, method 1000 may also be referred to a transesterification reaction or the transesterification method.

[0085] In one or more examples, fatty acid 110 includes at least one of palmitic, stearic, oleic, linoleic, and linolenic. Palmitic with 16 carbons and stearic with 18 carbons do not have any olefinic double bonds and they solidify at relatively high temperatures. If included in biodiesel, these two components will have “high cloud points” meaning they crystallize at relatively highDocket No. 333-003WO temperatures and plug fuel filters. Palmitic and stearic fractions must be removed from fatty acids before being reacted with methanol to form “fatty acid methyl esters.” Oleic, linoleic, and linolenic are fatty acids with 18 carbons; oleic has one olefinic bond, linoleic has two and linolenic has three. Fatty acids with more olefinic bonds are less likely to crystallize.

[0086] In one or more examples, implementation of method 1000 that utilize the liquid fatty acid (e.g., direct esterification method) enables the use of an “impure” fatty acid mixture. As an example, the liquid fatty acid can include crude tall oil (CTO) from a northern hardwood kraft pulp mill, in which the fatty acid content may be as low as 50% of the total and the other 50% is “unsaps” that do not have any carboxylic acid functionality. Use of these impure fatty acid mixtures may produce a variation of LFA 102 and / or LFAA 104 that are acceptable for use as biofuels or asphalt, or other end uses that are negligibly impacted by the presence of the impurities arising from the fatty acid feedstock.

[0087] Additional examples of fatty acid 112 that can be used as the reactant with lignin 120 include, but are not limited to, fatty acids derived from rapeseed oil. virgin olive oil, sunflower oil, safflower oil, soybean oil, palm oil, choice white grease, poultry fat, lard, edible tallow, yellow grease, or brown grease. In such examples, each source provides a different composition of saturated and unsaturated fatty acids including myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.

[0088] In one or more examples, the liquid fatty acid (e.g.. fatty acid 112) includes fatty acid mixtures from soybean oil, which has relatively small amounts of saturated fatty acids (Cl 6 palmitic and C18 stearic) but predominately oleic with one olefinic bond (C18:l) and linoleic acid with two double bonds (Cl 8:2). In one or more examples, the liquid fatty acid (e.g., fatty acid 112) is from corn oil, which is similar to soybean fatty acid. In one or more examples, the liquid fatty acid (e.g., fatty acid 112) is sunflower oil, which has a fatty acid composition similar to soybean and corn. In one or more examples, the liquid fatty acid (e.g., fatty acid 112) is palm oil, which is rich in saturated (non-olefinic) fatty acids, but which crystallize and generally cannot be used for biodiesel.

[0089] In one or more examples, liquid fatty acid ester (e.g., fatty acid esterll4) is biodiesel. In one or more examples, the liquid fatty acid ester (e.g., fatty acid esterl 14) is methanol, methylDocket No. 333-003WO oleate, or methyl hexanoate. Tn one or more examples, the liquid fatty acid ester (e.g., fatty acid esterll4) includes suitable methyl esters in biodiesel are the methyl esters product formed with the components of corn oil, soybean oil, or yellow grease. As an example, oleic acid would become methyl oleate in its ester form in biodiesel.

[0090] In one or more examples, at block 1004, method 1000 includes a step of mixing lignin 120 to fatty acid derivative 110. In one or more examples, lignin 120 is in a solid state (e.g., solid lignin). In one or more examples, lignin 120 is wet lignin 126. In one or more examples, lignin 120 is moist lignin 122. Tn one or more examples, lignin 120 is dry lignin 128. In one or more examples, lignin 120 and fatty acid derivative 110 are mixed in reactor 210, for example, using at least one agitator 214 (Fig. 5), for example under LFA reaction conditions 252 (e.g., Fig. 3B).

[0091] Generally, the slurries, mixtures, and products (e.g., lignin and fatty acid derivative) can require vigorous agitation, particularly, during the initial stages of the reaction. In one or more examples, agitator 214 includes one or more impellers designed to sweep the bottom of reactor 210.

[0092] In one or more examples, at block 1006, method 1000 includes a step of forming a first slurry. The first slurry includes fatty acid derivative 110, lignin 120, and water. In one or more examples, the water is weakly bound to lignin 120. In one or more examples, lignin 120 includes or takes the form of lignin filter cake. In one or more examples, wet lignin 126 has a moisture content of up to between approximately thirty-five percent (35%) to approximately and approximately fifty percent (50%) water by weight. In one or more examples, moist lignin 122 has a moisture content of up to between twenty percent (20%) and approximately thirty-five percent (35%) water by weight. In one or more examples, dry lignin 128 has a moisture content of up to between one percent (1%) and twenty percent (20%) water by weight, such as between five percent (5%) and approximately twenty percent (20%) water by weight, such as between five percent (5%) and approximately seven percent (7%) water by weight. However, in other examples, dry lignin 128 can have a moisture content of up to between approximately one percent (1%) and approximately five percent (5%) water by weight under certain drying conditions. Generally, the equilibrium moisture in lignin (when left open to a humid atmosphere) is between approximately twelve percent (12%) and approximately fifteen percent (15%)Docket No. 333-003WO depending on the moisture of the atmosphere. Tn these examples, lignin 120 with a moisture content of approximately twenty percent (20%) would be above the equilibrium level of moisture.

[0093] Examples of method 1000 disclosed herein advantageously enable the use of moist lignin 122 or dry lignin 128. The present disclosure recognizes that existing lignin processing methods require the use of lignin having less than eight percent (8%) moisture by weight. Lignin 120 having up to approximately twenty to twenty-five percent (20%-25%) moisture by weight is less expensive and safer than dry lignin. Use of lignin 120 having up to approximately twenty to twenty-five percent (20%-25%) moisture by weight eliminates problems of excessive dust associated with processing lignin having less than eight percent (8%) moisture (e.g., dry lignin dust is explosive). Use of the moist lignin 122 and dry lignin 128 also significantly reduces cost (e.g., fully drying lignin is expensive, protecting dry lignin from moisture is expensive, etc.).

[0094] In one or more example, the first slurry can have various ratios of fatty acid derivative 110 to lignin 120. In one or more examples, the fatty acid approximately 20 percent moisture by weight -to-lignin ratio is approximately 0.8 o 1.0 on a weight basis, meaning grams of fatty acid derivative 110 (e.g., fatty acids, fatty acid esters, biodiesels, etc.) to grams of lignin 120. In one or more examples, the fatty acid derivative -to-lignin ratio is between approximately 0.7 to approximately 1.2 on a weight basis. In these examples, lignin 120, for example, in the solid state, can be partially dehydrated, having a moisture content of between approximately ten percent (10%) and approximately twenty-five percent (25%), such as approximately twenty percent (20%) water by weight. In other examples, the ratio of the fatty acid derivative 110 to lignin 120 can vary depending on the source of the lignin or the type of lignin and the level of hydration of the lignin. Higher ratios of fatty acid derivative to lignin, greater than 1.2, can be used. In these reaction systems, the unreacted or excess fatty acid acts a solvent for the reaction mixture and facilitates the formation of a liquid product mixture at low temperature.

[0095] In one or more examples, at block 1008, method 1000 includes a step of heating the first slurry. In one or more examples, the first slurry is heated to a desired temperature, such as a first temperature. In one or more examples, the first temperature is between approximately 80°C and approximately 200°C, such as between approximately 100°C and approximately 120°C. InDocket No. 333-003WO one or more examples the first slurry is heated within reactor 210 using heating system 242 (e.g., as shown in Fig. 5).

[0096] In one or more examples, at block 1010, method 1000 includes a step of holding the first slurry at the first temperature.

[0097] In one or more examples, at block 1012, method 1000 includes a step of removing the water (e.g., weakly bound water) from the first slurry. In one or more examples, the water originates primarily from the lignin 120 and partially from fatty acid derivative 110, which will include some relatively small lever of moisture when added to form the first slurry. The water removed from the first slurry is converted to a liquid in external condenser 222 (e.g., Fig. 5).

[0098] In one or more examples, at block 1013, method 1000 includes a step of measuring the water removed from the first slurry. In one or more examples, the water removed from the first slurry is in the form of water vapor and is collected and condensed in condenser 222. Measuring the water removed from the first slurry enables the extent of reaction to be measured.

[0099] In one or more examples, at block 1014, method 1000 includes a step of forming a second slurry. The second slurry includes fatty acid derivative 110 and lignin 120.

[0100] In one or more examples, at block 1016, method 1000 includes a step of mixing catalyst 140 to the second slurry. In one or more examples, catalyst 140 includes or takes the form of water-soluble catalyst 141, such as acid catalyst 142 (e.g., a strong acid) or base catalyst 144. In one or more examples, catalyst 140 (includes an acid with a pKa value below approximately 2.5 and, preferably, below 0. In one or more examples, catalyst 140 includes sulfuric acid (H2SO4). In one or more examples, catalyst 140 includes phosphoric acid (H2SO4). In other examples, catalyst 140 includes nitric acid and hydrochloric acid. In these examples, sulfuric acid may be preferred due to its cost, low corrosion characteristics, and low probability for forming unwanted side products. In one or more examples, the acidic catalyst 140 is paratoluene sulfonic acid (pTSA). pTSA is more soluble in the organic (LFA and LFAA) phase, which is an advantage if the catalyst is left in the system for some applications.

[0101] In one or more examples, base catalyst 144 (e.g., NaOH) is added to the lignin-fatty acid mixture. In one or more examples, base catalyst 144 is added as a diluted solution (e.g., notDocket No. 333-003WO as solid NaOH). In one or more examples, lignin-fatty acid esters are formed when base catalyst 144 is dissolved in a moderate amount of water or methanol at the start of the reaction and then added.

[0102] In one or more examples, the step of mixing (e.g., block 1016) the catalyst is performed after substantially all the water is removed (e.g., block 1012) from the first slurry to enhance ester product yield for the reversible esterification reaction. In one or more examples, catalyst 140 is diluted, such as diluted sulfuric acid. Using a diluted acidic catalyst reduces the risk of forming a localized hot spot in the first reaction mixture and creating char, an unwanted solid material.

[0103] In one or more examples, at block 1018, method 1000 includes a step of forming a first reaction mixture. The first reaction mixture includes fatty acid derivative 110, lignin 120, and catalyst 140. In one or more examples, an amount of water comes in with catalyst 140 (e.g., diluted sulfuric acid). In these examples, the first reaction mixture includes fatty acid derivative 110, lignin 120, catalyst 140, and the water.

[0104] In one or more examples, at block 1020, method 1000 includes a step of removing the water, which was added with (e.g., by way of) catalyst 140, from the first reaction mixture. In some cases, a small amount of catalyst 140 may be lost when the water (that comes in with catalyst 140) is removed from the first reaction mixture. In one or more examples, the amount of water in catalyst 140 can be approximately zero or higher depending on the concentration of the acid used. However as previously mentioned, the use of concentrated acid may lead to localized “hot spots” and localized charring of the lignin, especially if the acid is added without stirring the mixture.

[0105] In one or more examples, at block 1021, method 1000 also includes a step of measuring the water removed from the first reaction mixture. In one or more examples, the water removed from the first reaction mixture is in the form of water vapor and is collected and condensed in condenser 222. Measuring the water removed from the first reaction mixture enables the extent of reaction to be measured.Docket No. 333-003WO

[0106] In one or more examples, the step of removing the water (e.g., block 1020) is achieved by heating (via heating system 242 in Fig. 5) and mixing (e.g., via agitator 214 in Fig. 5) the first reaction mixture. In one or more examples, the water associated with catalyst 140 is vaporized during the heating and removed as a vapor byproduct (e.g., water vapor byproduct). The vapor byproduct is the condensed in external condenser 222 (e.g., Fig. 5).

[0107] In one or more examples, at block 1022, method 1000 includes a step of mixing the first reaction mixture. Generally, the first reaction mixture needs to be continuously mixed during the process. In one or more examples, the first reaction mixture is mixed in reactor 210 using agitator 214. In one or more examples, agitator 214 includes or takes the form of a helical or anchor stirrer and rotates at a speed of between approximately 100 rpm and 400 rpm.

[0108] In one or more examples, at block 1024, method 1000 includes a step of heating the first reaction mixture. The first reaction mixture is heated to a desired temperature, such as a second temperature. In one or more examples, the second temperature is greater than the first temperature. In one or more examples, the second temperature is between approximately 130°C and approximately 250°C. In one or more examples, the first reaction mixture is heated in reactor 210 using heating system 242 (e.g., Fig. 5).

[0109] In one or more examples, at block 1026, method 1000 includes a step of holding the first reaction mixture at a desired temperature, such as the second temperature.

[0110] In one or more examples, at block 1028, method 1000 includes a step of removing a vapor byproduct from the first reaction mixture. In examples in which fatty acid derivative 110 is the liquid fatty acid (e.g., direct esterification method), the vapor byproduct is water vapor. In examples in which fatty acid derivative 110 is liquid fatty acid ester (e.g., transesterification method), the vapor byproduct is alcohol vapor.

[0111] In one or more examples, at block 1029, method 1000 includes as step of measuring the vapor byproduct removed from the first reaction mixture. In one or more examples, the vapor byproduct is collected and condensed in condenser 222 (e.g., Fig. 5). Measuring the vapor byproduct removed from the first reaction mixture enables the extent of reaction to be measured.Docket No. 333-003WO

[0112] In one or more examples, at block 1030, method 1000 includes a step of forming a first product mixture. The first product mixture includes LFA 102 (e.g., lignin-alkanoate product 100 in the form of crude LFA 202) and catalyst 140.

[0113] In one or more examples, the first product mixture is a final product of method 1000 and is stored and / or transported for a follow-on use. In other examples, as described herein below, the first product mixture is further processed (e.g., washed) to separate catalyst 140 and the LFA 102 (e.g., to produce final LFA product in liquid form or solid form as shown in Fig. 3C). In yet other examples, as described herein below, the first product mixture is further processed to form LFAA 104.

[0114] Referring now to Fig. 4B, in one or more examples, method 1000 includes a step of separating the first product mixture (e.g., separating LFA 102 and catalyst 140). LFA 102 and catalyst 140 can be separated by any suitable technique.

[0115] In one or more examples, at block 1032, method 1000 includes a step of cooling the first product mixture. In one or more examples, the first product mixture is cooled to a desired temperature, such as a third temperature. The third temperature is less than the second temperature. In one or more examples, the third temperature is between approximately 80°C and approximately 120°C. In one or more examples, the first product mixture is cooled in reactor 210 by cooling system 244 (e.g., Fig. 5).

[0116] In one or more examples, at block 1034, method 1000 includes a step of holding the product mixture at a desired temperature. In these examples, the product mixture is the first product mixture and the step of holding includes a step of holding the first product mixture at a desired temperature, such as the third temperature.

[0117] In one or more examples, at block 1036, method 1000 includes a step of mixing or adding wash water to the product mixture. In these examples, the product mixture is the first product mixture. In one or more examples, the wash water is added to the first product mixture in reactor 210 (e.g., Fig. 5). In one or more examples, the wash water is added to the first product mixture in extraction column 220 (e.g., Fig. 5). In these examples, the wash water serves as solvent 276 (Fig. 3C) and extracts catalyst 140 to form an aqueous solution.Docket No. 333-003WO

[0118] In one or more examples, at block 1038, method 1000 includes a step of forming an extraction mixture. In these examples, the extraction mixture is a first extraction mixture and includes LFA 102 (e.g., crude LFA 202), the acidic aqueous solution (including catalyst 140 and the wash water). In one or more examples, trace water is water that is left in the organic raffinate following extraction of catalyst 140. In one or more examples, addition of the wash water forms the extraction mixture, which includes an organic-rich phase and an aqueous phase. In these examples, the organic-rich phase includes LFA 102 (e.g., crude LFA 202) and the trace water (e.g., portion of the wash water remaining after extraction of catalyst 140). In these examples, the aqueous phase includes catalyst 140 and major water (a portion of the wash water that extracts catalyst 140).

[0119] In one or more examples, at block 1040, method 1000 includes a step of holding the extraction mixture at a desired temperature, such as the third temperature.

[0120] In one or more examples, at block 1042, method 1000 includes a step of removing the aqueous solution (e.g., acidic aqueous solution or basic aqueous solution) from the extraction mixture. In these examples, method 1000 includes a step of forming an organic-rich raffinate. The raffinate is formed via removing catalyst 140 and leaving LFA 102 (e.g., crude LFA 202 and trace water). In these examples, the raffinate includes LFA 102 (e.g., crude LFA) and the trace water. In one or more examples, the aqueous solution (acidic or basic aqueous solution) is removed and the organic-rich raffinate is formed in reactor 210 (e.g., Fig. 5). In one or more examples, the aqueous solution (acidic or basic aqueous solution) is removed and the raffinate is formed in extraction column 220 (Fig. 5). Typically, in an extraction column, the organic-rich raffinate will be the continuous phase and the aqueous phase (acidic or basic aqueous phase) will be the discontinuous phase, where the aqueous solution (e.g., acidic or basic aqueous solution) will be droplets that cascade downward through the organic-rich raffinate.

[0121] Alternatively, in one or more examples, at block 1044, method 1000 includes a step of decanting the extraction mixture. In these examples, method 1000 includes the step of forming the organic-rich raffinate. The raffinate is formed via decanting LFA 102 (and trace water). In these examples, the raffinate includes LFA 102 (e.g., crude LFA 202) and trace water. In one or more examples, LFA 102 is decanted and the raffinate is formed in reactor 210 (e.g., Fig. 5). InDocket No. 333-003WO one or more examples in a continuous extraction column, the organic-rich LFA is pumped into the bottom of the column, and pure wash water is pumped into the top. The organic-rich raffinate, from which the acidic catalyst has been extracted, is removed from a quiet zone at the top of the column and the aqueous acidic solution is removed from a separate quiet zone at the bottom.

[0122] In one or more examples, the steps for separating LFA 102 (e.g., crude LFA 202) and catalyst 140 can be done batch-wise by adding water to the first product mixture and separating the water phase containing catalyst 140 at the bottom of batch reactor 210 (e.g., Fig. 5). In one or more examples, the extraction is performed by pumping the first product mixture into the bottom of extraction column 220 (e.g., Fig. 5) and the wash water into the top of extraction column 220 and continuously and counter-currently extracting catalyst 140 into the water phase. In one or more examples, the bottom water phase is removed. In one or more examples, LFA 102 (e.g., lignin-rich organic phase) is decanted from the top.

[0123] In one or more examples, extraction temperatures can be near room temperature (e.g., 10-50°C). Higher temperatures may lead to the removal of the alkyl chains because the catalyst is still present in the extraction system (e.g., reversing the reactions). These unwanted reactions are slow at lower temperatures. In one or more examples, higher temperatures, in the 80°C - 120°C range or higher can decrease the likelihood of solids, which dramatically and negatively affect extraction efficiency and / or may increase the diffusion coefficients which enhance separation. In these examples, a solvent is added to enhance extraction efficiency, then operating at lower temperature will decrease the pressure requirement of the extraction column.

[0124] In one or more examples, the acidic aqueous solution (e.g., catalyst 140 in the acidic aqueous solution) is recycled for use in a lignin treating process (e.g., block 3004 in Fig. 6), such as to supplement the strong acid needed in that process.

[0125] In one or more examples, the trace water is removed from the raffinate to produce LFA 102.Docket No. 333-003WO

[0126] In one or more examples, at block 1048, method 1000 includes a step of holding the raffinate at a desired temperature. In one or more examples, the raffinate is held at the third temperature.

[0127] In one or more examples, at block 1050, method 1000 includes a step of applying vacuum to the raffinate. In one or more examples, the organic-rich raffinate is also heated (e.g., to a temperature of approximately 100°C) during application of vacuum and drying. In one or more examples, organic raffinate after the water-removal step can be maintained at an elevated temperature, likely greater than 100°C to assure the product is a liquid. As an example, the asphalt industry typically ships asphalt at 175°C to avoid formation of solids. In some examples, the final product may still contain some water (likely less than 5%). so it is not completely dry.

[0128] In one or more examples, at block 1052, method 1000 includes a step of removing the trace water from the raffinate. In one or more examples, application of vacuum to the raffinate removes the vast majority of the trace water and dries LFA 102. In one or more examples, the final lignin-alkanoate product 100 100 is stored at temperatures greater than approximately 100°C, there will be almost no water in the product.

[0129] In one or more examples, at block 1053, method 1000 includes a step of measuring the trace water removed from the raffinate. In one or more examples, the trace water removed from the raffinate is in the form of water vapor and is collected and condensed in condenser 222 (e.g., Fig. 5). Measuring the trace water removed assures the drying step is complete.

[0130] In one or more examples, at block 1054, method 1000 includes a step of producing the LFA 102 (e.g., liquid LFA product 282 or solid LFA product 284 in Fig. 3C). In one or more examples, the LFA 102 is a produced as a liquid in a dry (e.g., substantially free of water) and usable form.

[0131] In one or more examples, at block 1056, method 1000 includes a step of cooling LFA 102 (e.g., lignin-alkanoate product 100). In one or more examples, LFA 102 is cooled to a desired temperature, such as a fourth temperature that is less than the third temperature. In one or more examples, the fourth temperature is ambient temperature. In one or more examples, LFA 102 is cooled in reactor 210 using cooling system 244 (e.g., Fig. 5). In one or more examples,Docket No. 333-003WOLFA 102 is cooled in a storage tank (e.g., storage tank 236 in Fig. 5) using the cooling system 244. In other examples, LFA 102 is stored at temperatures greater than approximately 100°C.

[0132] In one or more examples, at block 1058, method 1000 includes a step of storing LFA 102 (e.g., lignin-alkanoate product 100). In one or more examples, LFA 102 is transferred from reactor 210 to storage tank 236 (e.g., Fig. 5).

[0133] Referring now to Fig.4C, alternatively, in one or more examples, rather than washing the first product mixture to separate catalyst 140 and crude LFA 202 and producing the final LFA product, the first product mixture is further processed to form LFAA 104.

[0134] In one or more examples, at block 1060, method 1000 includes a step of mixing alcohol 116 to the first product mixture.

[0135] In one or more examples, alcohol 116 includes a long-chain alcohol with at least 4 carbons. In one or more examples, alcohol 116 includes or takes the form of a low-volatility alcohol. In one or more examples, alcohol 116 includes or takes the form of a high molecular weight alcohol. In one or more examples, alcohol 116 includes or takes the form of butanol (C4) and has a vapor-pressure of less than approximately 15 psi at 200°C. As such, utilization of the non-volatile alcohol or the high molecular weight alcohol enables use of a low-pressure reactor (e.g. reactor 210). The use of lower MW alcohols such as propanol, ethanol and methanol have two strong disadvantages: 1) the reactor must be rated at high pressure higher than the vapor pressure which for instance for propanol is 480 psi at 200°C and 2) the lower MW alcohol reactant will be lost from the reactor with the water of reaction (water byproduct) that is formed and must be removed. In one or more examples, the selected alcohol has a vapor pressure less than that of water at the reaction temperature.

[0136] In one or more examples, at block 1062, method 1000 includes a step of forming a second reaction mixture. In one or more examples, the second reaction mixture includes LFA 102 (e.g., crude LFA 202), catalyst 140, alcohol 116, and the water byproduct.

[0137] In one or more examples, at block 1064, method 1000 includes a step of heating the second reaction mixture. In one or more examples, the second reaction mixture is heated to a desired temperature, such as a fifth temperature. In one or more examples, the fifth temperatureDocket No. 333-003WO is greater than the second temperature. Tn one or more examples, the fifth temperature is less than the second temperature. In one or more examples, the fifth temperature is greater than the third temperature. In one or more examples, the fifth temperature is between approximately 80°C to 200°C. In one or more examples, the second reaction mixture is heated in reactor 210 using heating system 242 (e.g., Fig. 5).

[0138] In one or more examples, at block 1066, method 1000 includes a step of holding the second reaction mixture at a desired temperature. In one or more examples, the second reaction mixture is held at the fifth temperature.

[0139] In one or more examples, at block 1068, method 1000 includes a step of removing the water byproduct from the second reaction mixture.

[0140] In one or more examples, at block 1069, method 1000 includes a step of measuring the water byproduct removed from the second reaction mixture. In one or more examples, the water byproduct removed from the second reaction mixture is in the form of water vapor and is collected and condensed in condenser 222 (e.g., Fig. 5). Measuring the water byproduct removed from the second reaction mixture enables the extent reaction to be measured.

[0141] In one or more examples, at block 1070, method 1000 includes a step of forming a second product mixture. The second product mixture includes LFAA 104 (e.g., crude LFAA 204) and catalyst 140.

[0142] In one or more examples, the second product mixture is a final product of method 1000 and is stored and / or transported for a follow-on use. In other examples, as described herein, the second product mixture is further processed (e.g., washed) to separate catalyst 140 and LFAA 104.

[0143] In one or more examples, at block 1072, method 1000 includes a step of cooling the second product mixture. In one or more examples, the second product mixture is cooled to a desired temperature, such as sixth temperature. In one or more examples, the sixth temperature is less than the fifth temperature. In one or more examples, the sixth temperature is between approximately 20°C and 120°C.Docket No. 333-003WO

[0144] Referring now to Figs. 4B and 4C, in one or more examples, method 1000 includes a step of separating the second product mixture (e.g., separating LFAA 104 and catalyst 140). LFAA 104 and catalyst 140 can be separated by any suitable technique, as described herein.

[0145] In one or more examples, at block 1034, method 1000 includes the step of holding the product mixture at a desired temperature. In one or more examples, the product mixture is the second product mixture and the step of holding includes a step of holding the second product mixture at a desired temperature, such as the sixth temperature.

[0146] In one or more examples, at block, 1036, method 1000 includes the step of mixing the wash water to the product mixture. In these examples, the product mixture is the second product mixture. In one or more examples, the wash water or extraction solvent (e.g., solvent 276 in Fig. 3C) is added to the second product mixture in reactor 210 (e.g., Fig. 5) such that the resulting mixture forms two separate immiscible phases and the reactor is used as a single-stage extractor. In one or more examples, the wash water or extraction solvent is added to the second product mixture in counter-current extraction column 220 (e.g.. Fig. 5). When the extraction column is used, the wash water or extraction solvent (e.g., solvent 276) is added to the top of the extractor and the second product mixture is added to the bottom of the column such that buoyancy differences will ensure a counter-current flow of the two immiscible phases in the tower achieving multiple stages of chemical separation. In these examples, the water extracts catalyst 140 to form the acidic aqueous solution.

[0147] In one or more examples, at block 1038, method 1000 includes the step of forming the extraction mixture. In these examples, the extraction mixture is a second extraction mixture and includes LFAA 104 (e.g., erode LFAA 204), the acidic aqueous solution (including catalyst 140 and the wash water), and any trace water. In one or more examples, the trace water is water that is left in the organic-rich raffinate following extraction of catalyst 140.

[0148] In one or more examples, at block 1040, method 1000 includes the step of holding the extraction mixture at a desired temperature, such as the sixth temperature.

[0149] In one or more examples, at block 1042, method 1000 includes the step of removing the acidic aqueous solution from the extraction mixture to form the organic-rich raffinate. InDocket No. 333-003WO these examples, method 1000 includes a step of forming a raffinate. The organic-rich raffinate is formed via removing the extract solvent that contains catalyst 140 and leaving LFAA 104 (and trace water). In these examples, the raffinate includes LFAA 104 and trace water. In one or more examples, the added water or extract solvent is added to the second product mixture yielding the aqueous solution (e.g., acidic aqueous solution) or extract phase. In one or more examples, he (e.g., acid containing) aqueous extract phase is removed leaving the organic-rich raffinate in reactor 210 (e.g., Fig. 5) or single-stage extractor. In one or more examples, the aqueous extraction solvent is contacted with the second reaction product in a counter-current extraction column 220 (e.g., Fig. 5) and the resulting aqueous solution (acidic aqueous solution) is removed and the organic -rich raffinate product is separately isolated.

[0150] Alternatively, in one or more examples, at block 1044, method 1000 includes a step of decanting the extraction mixture. In these examples, method 1000 includes the step of adding the aqueous extraction solvent and forming the organic-rich raffinate as a separate immiscible phase. The raffinate is isolated from the aqueous acid solution via decanting LFAA 104 (and trace water). In these examples, the raffinate includes LFAA 104 and trace water. In one or more examples, LFAA 104 is a component in the organic-rich raffinate, and this phase is isolated by decanting the mixture from extraction solvent-raffinate mixture in reactor 210 (e.g., Fig. 5). In one or more examples, a raffinate phase that contains LFAA 104 is formed in extraction column 220 (e.g., Fig. 5).

[0151] In the case where an organic solvent is added with wash water to form the extraction mixture, the solvent must be removed with the trace water in the evaporation (drying) step. Leaving even small amounts of solvent in the final product risks the solvent vaporizing in storage tanks and forming a combustible mixture in the vapor space of tanks.

[0152] In one or more examples, the steps for separating LFAA 104 and catalyst 140 can be done batch-wise by adding water to the second product mixture and separating the water phase containing catalyst 140 at the bottom of batch reactor 210 (e.g., Fig. 5). In one or more examples, the extraction is performed by pumping the second product mixture into the bottom of extraction column 220 (e.g., Fig. 5) and the wash water into the top of extraction column 220 in a continuous fashion and counter-currently extracting catalyst 140 into the water phase. In one orDocket No. 333-003WO more examples, the bottom aqueous phase (e.g., acidic aqueous phase) is removed. Tn one or more examples, the organic-rich raffinate phase containing LFAA 104 (e.g., lignin-rich organic phase) is removed from the top. In one or more examples, decanting would only happen when the reactor is used as an extraction vessel not in the extractor column.

[0153] In one or more examples, the acidic aqueous solution (e.g., catalyst 140 in the aqueous solution, such as acid catalyst 142 in the acidic aqueous solution) is recycled for use in a lignin treating process (e.g., block 3004 in Fig. 6), such as to supplement the strong acid needed in that process. The strong acid extracted from the final LFA / LFAA product can be concentrated by removing water in a flash distillation process and used as the acid catalyst in a subsequent reaction process. Alternatively, when the “Liquid Lignin” process is located on the same host mill site as the SLRP lignin recovery process as shown in Figure 29, the reconcentrated acid from the extraction process can be used as the strong acid required for the SLRP process.

[0154] In one or more examples, the trace water is removed from the raffinate to produce LFAA 104.

[0155] In one or more examples, at block 1048, method 1000 includes the step of holding the raffinate at a desired temperature. In one or more examples, the raffinate is held at the sixth temperature.

[0156] In one or more examples, at block 1050, method 1000 includes the step of applying the vacuum to the raffinate. In these examples, application of vacuum to the raffinate removes the trace water from LFAA 104. In one or more examples, the raffinate is also heated (e.g., to a temperature of approximately 100°C) during application of vacuum and drying.

[0157] In one or more examples, at block 1052, method 1000 includes the step of removing the trace water from the raffinate. In one or more examples, application of vacuum to the raffinate removes the trace water from LFAA 104. In these examples, removing the trace water and drying mean the same thing.

[0158] In one or more examples, at block 1053, method 1000 includes the step of measuring the trace water removed from the raffinate. In one or more examples, the trace water removed from the raffinate is in the form of water vapor and is collected and condensed in condenser 222Docket No. 333-003WO(e.g., Fig. 5). Measuring the trace water removed from the raffinate enables the extent of drying to be measured.

[0159] In one or more examples, at block 1080, method 1000 includes a step of producing LFAA 104 (e.g., liquid LFAA product 286 or solid LFAA product 288 in Fig. 3C). In one or more examples, LFAA 104 is a produced as a liquid in a dry (e.g., substantially free of water) and usable form.

[0160] Referring to Fig. 4C, in one or more examples, at block 1082, method 1000 includes a step of cooling LFAA 104 (e.g., lignin- alkanoate product 100). In one or more examples, LFAA 104 is cooled to a desired temperature, such as the fourth temperature that is less than the third temperature. In one or more examples, the fourth temperature is ambient temperature. In one or more examples, LFAA 104 is cooled in reactor 210 using cooling system 244 (e.g., Fig. 5). In one or more examples, LFAA 104 is cooled in a storage tank (e.g., storage tank 236) using cooling system 244 (e.g., Fig. 5).

[0161] In one or more examples, at block 1084, method 1000 includes a step of storing LFAA 104 (e.g., lignin-alkanoate product 100). In one or more examples, LFAA 104 is transferred from reactor 210 to storage tank 236 (e.g.. Fig. 5).

[0162] In one or more examples, the second product mixture (formed at block 1070) can be a solid-liquid slurry. An alternative technique for separating LFAA 104 and catalyst 140 involves adding an organic solvent that mixes with LFAA products and forms a homogeneous solution. The homogeneous solution of LFAA in organic solvent can be contacted with water in a countercurrent liquid-liquid extraction column. This alternative technique may enhance the extraction of catalyst 140. Generally, this alternative wash process involves dissolving the LFAA 104 in a hydrophobic organic solvent, such as C6 to C15 hydrocarbons commonly found in petroleum diesel and gasoline range products. While in this example, the organic solvent is mixed with the LFAA 104, in other examples, the organic solvent can be mixed with LFA 102 in a similar way.

[0163] In one or more examples, at block 1074, method 1000 includes a step of mixing the organic solvent to the second product mixture. In these examples, LFAA 104 dissolves in the organic solvent. As such, method 1000 includes a step of dissolving LFAA 104 in the organicDocket No. 333-003WO solvent. This will improve the efficiency of the extraction of the strong acid by lowering the viscosity of the organic-rich phase, and the solvent is more likely to dissolve and keep as a liquid any fraction of the LFA / LFAA that would otherwise form a solid. The use of high volatility solvents will require higher pressures and / or lower temperatures for the extraction process. If necessary, the solvent and any trace levels of water can be removed from the final LFA / LFAA product via a flash evaporation process.

[0164] In one or more examples, the organic solvent has low water solubility. In one or more examples, the organic solvent includes kerosene or any mixture of C6 to Cl 5 hydrocarbons.

[0165] In one or more examples, at block 1076, method 1000 includes a step of forming a solvent-product mixture. In these examples, the solvent-product mixture is formed by mixing the organic solvent with the second product mixture and dissolving LFAA 104. The solvent-product mixture includes LFAA 104, catalyst 140, and the organic solvent.

[0166] In one or more examples, the solvent-product mixture is then water washed and catalyst 140 is separated and removed, for example, using the operational steps described above.

[0167] Referring to Figs. 3B and 3C, in one or more examples, at block 1034, method 1000 includes the step of holding the product mixture at a desired temperature. In these examples, the product mixture is the solvent-product mixture and the step of holding includes a step of holding the solvent-product mixture at a desired temperature, such as the third temperature or the sixth temperature.

[0168] In one or more examples, at block 1036, method 1000 includes the step of mixing the wash water to the product mixture. In these examples, the product mixture is the solvent-product mixture. In one or more examples, the wash water is added to the solvent-product mixture in reactor 210 (e.g., Fig. 5) to achieve a single-stage of liquid-liquid extraction. In one or more examples, the wash water is added to the solvent-product mixture in the liquid-liquid extraction column 220 (e.g., Fig. 5). In these examples, the wash water absorbs or extracts catalyst 140 (e.g., acidic catalyst) to form the aqueous solution (e.g., acidic aqueous solution).

[0169] In one or more examples, at block 1038, method 1000 includes the step of forming the extraction mixture. In these examples, the extraction mixture is a third extraction mixture andDocket No. 333-003WO includes LFAA 104, the organic solvent, the aqueous solution (e.g., acidic aqueous solution) (including catalyst 140 (e.g., acid catalyst 142) and the wash water).

[0170] In one or more examples, at block 1040, method 1000 includes the step of holding the extraction mixture at a desired temperature, such as the sixth temperature.

[0171] In one or more examples, at block 1042, method 1000 includes the step of removing the aqueous solution (e.g., acidic aqueous solution) from the extraction mixture to form the organic -rich raffinate. In these examples, at block 1046, method 1000 includes the step of forming the raffinate via removing catalyst 140 and leaving LFAA 104. In these examples, the raffinate includes LFAA 104 and any trace water.

[0172] In one or more examples, the water extract phase, which contains the acid, will be immiscible with the organic -rich raffinate phase (like Italian salad dressing). The two immiscible liquid phases are easily separated - by decantation for the reactor or by physically separated exit streams that make use of the buoyancy differences of the two phases to isolate the two separate liquids (water sinks and organics float). The organic solvent is fully miscible with the lignin product and can only be removed by heating (vaporizing or boiling away the solvent) and possibly pulling a vacuum (which lowers the temperature needed to get the solvent to vaporize). A process step where the solvent is removed by adding heat and possibly a vacuum, and the solvent vapors are collected using a condenser. The condensed solvent could then be recycled to the pre-extraction mixing step. Thus, there would be 1) a step to mix solvent with the LFAA product creating a homogeneous liquid, 2) a water wash step - in the reactor or extraction column, 3) a decantation step to separate the aqueous acid solution from the raffinate, and 4) a solvent removal step that involves heat and vacuum because the solvent must be vaporized to get it away from the LFAA product in the solvent-LFAA raffinate.

[0173] Alternatively, in one or more examples, at block 1044, method 1000 includes the step of decanting the extraction mixture. In these examples, LFAA 104 is decanted from extraction mixture to form the organic -rich raffinate. In these examples, at block 1046, method 1000 includes the step of forming the raffinate via decanting LFAA 104. In these examples, the raffinate includes LFAA 104 and any trace water.Docket No. 333-003WO

[0174] In one or more examples, the trace water is removed from the raffinate to produce LFAA 104.

[0175] In one or more examples, at block 1048, method 1000 includes the step of holding the organic-rich raffinate at a desired temperature. In one or more examples, the raffinate is held at the sixth temperature.

[0176] In one or more examples, at block 1050, method 1000 includes the step of applying the vacuum to the raffinate. In these examples, application of vacuum to the raffinate removes the trace water and dries LFAA 104. In one or more examples, the raffinate is also heated (e.g., to a temperature of approximately 100°C) during application of vacuum and drying.

[0177] In one or more examples, at block 1052, method 1000 includes the step of removing the trace water from the raffinate.

[0178] In one or more examples, at block 1052, method 1000 includes the step of measuring the trace water removed from the raffinate. In one or more examples, the trace water removed from the raffinate is in the form of water vapor and is collected and condensed in condenser 222 (e.g., Fig. 5). Measuring the trace water removed from the raffinate enables the dryness of the LFAA product to be measured. This step will not provide any information about the extent of reaction because we just previously added water to the system. This measuring water step can only let us know if removed all of the water that we added during the extraction step (assuming we know how much water was decanted away from the raffinate - which is something that could be measured).

[0179] In one or more examples, at block 1080, method 1000 includes the step of producing LFAA 104 (e.g.. lignin-alkanoate product 100). In one or more examples, the LFAA 104 is a produced as a liquid or liquid slurry in a dry (e.g., substantially free of water) and usable form.

[0180] Referring to Fig. 4C, in one or more examples, at block 1082, method 1000 includes the step of cooling LFAA 104 (e.g., lignin-alkanoate product 100). In one or more examples, LFAA 104 is cooled to a desired temperature, such as the fourth temperature that is less than the third temperature. In one or more examples, the fourth temperature is ambient temperature. In one or more examples, LFAA 104 is cooled in reactor 210 using cooling system 244 (e.g., Fig.Docket No. 333-003WO5). Tn one or more examples, LFAA 104 is optionally cooled in a storage tank (e.g., storage tank 236) using cooling system 244 (e.g., Fig. 5).

[0181] In one or more examples, the cooling step (e.g., at block 1082) can be changed to a heating step. The cooling step can be optional. There may be a need to keep the LFAA product heated to ensure that it stays in a mostly liquid form. If the product is cooled it is more likely to exist as a slurry of liquid and solidified products. Therefore, the product should be maintained at a temperature between 20°C and 150°C, (more likely 50°C-150°C).

[0182] In one or more examples, at block 1084, method 1000 includes the step of storing LFAA 104 (e.g., lignin-alkanoate product 100). In one or more examples, LFAA 104 is transferred from reactor 210 to storage tank 236.

[0183] Referring now to Fig. 5, by way of examples, the present disclosure is also directed to system 200 for esterifying lignin and producing the lignin-alkanoate product 100 (e.g., LFA 102 and / or LFAA 104). The following are examples of system 200, according to the present disclosure. Examples of system 200 include a number of elements, features, and components. In one or more examples, system 200 is constructed for implementation of the various operational steps of method 2000 (Figs. 4A-4C) and method 2000 (Figs. 3A-3C). Not all of the elements, features, and / or components described or illustrated in one example are required in that example. Some or all of the elements, features, and / or components described or illustrated in one example can be combined with other examples in various ways without the need to include other elements, features, and / or components described in those other examples, even though such combination or combinations are not explicitly described or illustrated by example herein.

[0184] In one or more examples, system 200 includes batch reactor 210. Batch reactor 210 is configured to be charged with the various mixtures and for processing the various products. In one or more example, system 200 and methods 2000 and 1000 are configured for batch processing of lignin. In one or more examples, system 200 includes a plurality of batch reactors 212. In these examples, batch reactors 212 operate in parallel to synthesize LFA 102 and / or LFAA 104 using fatty acid derivative 110 and alcohol 116 (e.g., non-volatile alcohol) and using catalyst 140 (e.g., sulfuric acid). Batch reactor 210 (e.g., each one of batch reactors 212) includes agitator 214 configured for mixing the contents of batch reactor 210. System 200 includes atDocket No. 333-003WO least one condenser 222. Tn one or more examples, system 200 also includes storage tank 223 for collection and storage of alcohol 116 (e.g., methanol), for example, when biodiesel is used as the fatty acid derivative 110. System 200 includes at least one extraction column 220 (e.g., a continuous counter-current extraction column) configured to remove catalyst 140 (e.g., sulfuric acid catalyst) from LFA 102 and / or LFAA 104 and inorganic salts in the lignin starting material (e.g., solid lignin). System 200 includes a plurality of storage tanks 230, including fatty acid storage tank 231 (storing fatty acid derivative 110), alcohol storage tank 232 (storing alcohol 116), lignin storage tank 233 (storing lignin 120), catalyst storage tank 234 (e.g.,, storing catalyst 140), intermediate storage tank 235 (storing LFA 102 and / or LFAA 104) between batch reactor 210 and extraction column 220), and finished product storage tank 236 (storing the finished product of LFA 102 and / or LFAA 104). System 200 also includes heating system 242, such as a hot oil system, configured for heating batch reactor 210 (e.g., each one of batch reactors 212). System 200 includes cooling system 244, such as a cooling water system, configured for cooling batch reactor 210 (e.g.. each one of batch reactors 212). In some examples, system 200 includes a plurality of storage tankers 250 (e.g., railcars or tanker cars) for transport of the finished product of LFA 102 and / or LFAA 104 from a loading facility.

[0185] For large-scale operations, multiple batch reactors 212 can be arranged in parallel and sequenced so that batch reactors 212 operate synchronously, for instance so that no two reactors are undergoing the heating phase at the same time. To maximize output, LFA or LFAA containing residual sulfuric acid from batch reactors 212 can be pumped to intermediate storage tank 235 after the temperature reaches 120°C in the cooling stage. In these examples, the intermediate product of LFA and / or LFAA can be pumped continuously to the bottom of extraction column 220 in which LFA 102 and / or LFAA 104 would rise as the discontinuous phase. Pure wash water injected at the top of extraction column 220 will fall as the continuous phase, extracting residual sulfuric acid and other inorganics.

[0186] In one or more examples, the stoichiometric amount of fatty acid and alcohol are based on the premise: four moles of fatty acid are reacted with each of the four hydroxyl groups per 1000 MW units of the lignin polymer; one moles of butanol is reacted with one carboxyl group per 1000 MW units of the lignin polymer; and five moles of water are evolved during the esterification reactions.Docket No. 333-003WO

[0187] In one or more examples, each reactor 210 is jacketed for hot-oil heating. In one or more examples, each reactor 210 has an associated condenser (e.g., condenser 222) for capturing the water vapor exiting reactor 210 from the esterification reactions. In one or more examples, each reactor 210 has a pump-around loop with a heat-exchanger for cooling LFA 102 and / or LFAA 104 after each reaction.

[0188] In one or more examples, lignin storage tank 233 is a lignin silo designed to hold a supply of lignin 120 (e.g., between 5% and 25% moisture lignin), such as from the treating process (e.g., block 3004 in Fig. 6). In one or more examples, the silo has a specially designed system to allow lignin 120 to be delivered from the lignin processing system 300 (Fig. 6) at host mill 304 in containers, dumped into a receiving hopper, then lifted to the top of the silo. In one or more examples, the silo has a tubular drag-chain-and-disc system to deliver lignin charge to each of reactors 212. Lignin 120 can have a high probability of packing tightly and “freezing” an auger. In one or more examples, the silo has a 45°-sloped bottom slope down to a chamber from which the tubes with drag chains that deliver lignin 120 to reactors 212. In one or more examples, other solid handling equipment could be used not just the equipment listed.

[0189] In one or more examples, the aqueous water phase will flow down extraction column 220 as a continuous phase (droplets) and the organic phase will rise as the discontinuous phase. Extraction column 220 can be controlled at elevated temperature (~120°C) and pressure to reduce viscosity of the organic phase and promote the rate of transfer of sulfuric acid from the organic phase into the water. The counter-current extraction column will minimize the quantity of wash water needed and more completely removes sulfuric acid from LFA 102 or LFAA 104.

[0190] In one or more examples, extraction column 220 is 40 inches in diameter. Extraction column 220 can have any suitable height, recognizing that higher dimensions favor longer contact times for the continuous water phase with the discontinuous LFA or LFAA phase. The pressure of extraction column 220 should be from 0 to 45 psig. For example, if extraction column 220 operates at 120°C, the pressure to keep the water as a liquid phase is 30 psig. In one or more examples, water extraction at that temperature in a counter-current column removes substantially all of catalyst 140 (e.g., H2SO4) and any residual inorganic salts (mainly Na2SC>4) that may have entered the process with lignin 120. Inorganics in the low ppm (less than 100Docket No. 333-003WO ppm) may be possible. Pure water should be used as the extraction “solvent.” If the water mass flow is 20% of the LFA or LFAA mass flow, and the concentration of H2SO4 in the inlet LFA or LFAA is 5%, then the concentration of H2SO4 in the extract phase should be about 20%. The solubility of Na2SC>4 in water at 120°C is >30%, so this low water flow should be sufficient to fully dissolve any residual salts from the lignin feedstock. In one or more examples, extraction column 220 is packed with (e.g., Flexipac) structured packing to ensure proper distribution of the discontinuous organic phase. In one or more examples, the diameter of the tower will vary depending on the flow rate of water and LFA / LFAA / Solvent. Example of diameter is greater than 10 inches. In one or more examples, 100 g LFA having 5 g acid contacted with 20 g water means that the resulting aqueous extract would contain 20 g of water and 5 g acid (5 g acid / 25 g total) or a 20% acid in water solution. In one or more examples, the discontinuous and continuous phases could be switched.

[0191] Referring now to Fig. 6, in one or more examples, system 200 can be integrated into a larger lignin processing system 300 and / or method 3000. In one or more examples, system 200 is used to produce LFA 102 and / or LFAA 104 and is located on an existing pulp mill site (e.g., pulp mill 304 in Fig. 6), which hosts a solid lignin processing system 300 and method 3000, so existing infrastructure such as waste treatment and rail connections can be shared. As illustrated in Fig. 6, in one or more examples, method 3000 advantageously integrates methods 2000 and 1000 and system 200 disclosed herein with a pulp milling process (e.g., at a pulp mill site) to increase efficiency and cost of lignin processing and production of lignin-alkanoate product 102 and alkyl lignin-alkanoate ester product 104 (i.e. LFA and / or LFAA).

[0192] In one or more examples, at block 3002, method 3000 includes a step of providing black liquor 302. Black liquor 302 can be provided in any suitable way or by any suitable technique. In one or more examples, black liquor 302 is a byproduct of a kraft pulping process, for example, performed at pulp mill 304 and used in the paper and pulp industry. In one or more examples, black liquor 302 is a dark, viscous liquid containing lignin, hemicellulose, and various inorganic chemicals that are released when wood is converted into pulp. During pulping, lignin and other non-cellulosic components are separated from the cellulose fibers, resulting in black liquor as a residue.Docket No. 333-003WO

[0193] In one or more examples, at block 3004, method 3000 includes a step of processing or otherwise treating black liquor 302 to form lignin 120 (e.g., solid lignin). In one or more examples, black liquor 302 is processed using the SLRP process to form lignin 120, for examples, according to the process for treating lignin disclosed in U.S. Patent No. 11,866,456, the entirety of which is incorporated by reference herein. Fig. 7 is an illustrative example of the process for treating lignin (e.g., SLRP process). Fig. 8 illustrates an example of lignin processing system 300 and method 3000 as integrated into pulp mill 304. In other examples, lignin 120 can be derived or formed using any other suitable means, method, or technique.

[0194] In one or more examples, at block 3006, method 3000 includes a step of processing lignin 120 to form lignin-alkanoate product 102. In one or more examples, fatty acid derivative 110 is reacted with lignin 120 to the form lignin-alkanoate product 100 (e.g., LFA 102 in Fig. 1). In one or more examples, processing the lignin 120 and fatty acid derivative 110 to form LFA 102 is performed according to examples of the method 2000 or 1000 or using examples of system 200. In one or more examples, alcohol 116 is reacted with lignin-alkanoate 102 (e.g., LFA 102) to form alkyl lignin-alkanoate ester product 104 (e.g., LFAA 104 in Fig. 2). In one or more examples, processing lignin 120, fatty acid derivative 110, and alcohol 116 to form LFAA 104 is performed according examples of the method 2000 or 1000 or using examples of system 200.

[0195] In one or more examples, at 2008, method 3000 includes a step of storing alkyl lignin- alkanoate ester product, such as for transportation to a consumer. In one or more examples, lignin-alkanoate or alkyl lignin-alkanoate ester products (e.g., LFA 102 or LFAA 104) produced in liquid or liquid slurry form. In one or more examples, the alkyl lignin-alkanoate ester product (LFAA 104) is transferred from system 200 to storage tanker 250. In these examples, lignin- alkanoate 102 or alkyl lignin-alkanoate ester product 104 (e.g., LFA 102 or LFAA 104 in liquid form) is transferred to a mobile storage tanker for delivery to a customer. For example, lignin- alkanoate 102 or alkyl lignin-alkanoate ester product 104 can be loaded onto railcars and shipped to consumers, such as oil companies for use as a precursor for biofuels, asphalt companies as a green component and rejuvenator, and carbon companies as a renewable organic binder.Docket No. 333-003WO

[0196] Additionally, lignin-alkanoate 102 or alkyl lignin-alkanoate ester product 104 (e.g., LFA 102 or LFAA 104) is soluble in light gas oil (e.g., kerosene) and is, therefore, a viable precursor for biofuels. LFAA 104 has approximately 14 percent oxygen, which can be removed by a catalytic hydrotreater of an oil refinery to produce a biofuel.

[0197] Generally, the quantity of fatty acid derivative 110 and alcohol 116 to be added can be determined in one of two ways. In a first way, lignin 120 to be used can be analyzed using NMR - preferably phosphorous NMR - to determine the number and type (aliphatic, phenoxy) of hydroxyl groups and carboxylic groups on the lignin polymer. The quantity of fatty acid derivative 110 to be used and quantity of alcohol 116 to be used can then be calculated from these analytical data. In a second way, the amount of fatty acid derivative 110 to be added can be calculated using analytical data. Then the amount of alcohol 116 to be added can be calculated by taking a sample at the completion of the first esterification step. The sample can then be washed with water to remove the strong acid catalyst, and the acid number can be measured on the remaining organic phase. This acid number is a direct measure of the remaining “free” carboxyl groups, which then allows calculating the amount of alcohol to be added.

[0198] Further, the present disclosure recognizes that the current use of crude oil as the primary feedstock for most liquid fuels and commodity polymers is problematic for ongoing efforts to address pollution, global warming, and geopolitical unrest. Thus, numerous corporations, universities, and governments are investigating the use of renewable materials to supplant some of the oil that is used for material and fuel applications. For example, the airline industry is highly interested in finding a renewable fuel source that is cost competitive with the currently used fossil fuels. The problem with most renewable materials derived from low-cost plant sources (e.g., trees and grasses) is that the plant-based materials are polar organic species, and the existing fuels are all very non-polar. In other words, a mixture of unmodified fossil and biobased fuels would phase separate into a heterogeneous mixture. Current engine designs cannot handle a mixed phase fuel. Thus, chemical technologies are needed to convert polar plantbased products into non-polar liquids that could be easily mixed with fossil fuels and be compatible with equipment at fossil fuel-based delivery and storage facilities.Docket No. 333-003WO

[0199] The present disclosure also recognizes that plant-based materials are abundant and could be an excellent source for renewable fuels. These materials are largely comprised of three components: cellulose (a crystalline polymer made of sugar groups), hemi-cellulose (a random polymer made of sugar groups) and lignin (an aromatic polymer comprised of several different structural groups). The cellulose provides rigidity for the plant, allowing it to grow tall, whereas the lignin acts like a glue holding the various components together, and it also acts as an insect repellent. Traditionally, paper mills take in trees as feedstock, chemically separate these three components, use the cellulose for paper products, and burn the lignin for fuel in high-cost specialty boilers. The major components of other plant materials, such as crop waste and switch grass, could be similarly grown and similarly fractioned to create a lignin fraction. To date, no one has been successful at developing a low-cost process for converting lignin from plants into a useable commodity for the chemical, fuel, and material industries.

[0200] Generally, examples of the methods and systems disclosed herein provide a novel, simple, and low-cost alternative for converting lignin into a hydrophobic form that enables its use as a renewable feedstock for fuels and chemicals that are historically derived from fossil fuels. This is achieved by reacting the lignin with other low-cost, long-chain acid and alcohol reagents derived from plant products that are naturally compatible with fossil fuel derived products. These reactions are expressed herein above in Equations 1A, IB, 2, 3, 4A and 4B.

[0201] Three major applications are envisioned for a portfolio of LFA and / or LFAA products: (1) Petroleum companies currently use fatty acid as feedstock to their refineries to make “green gasoline and diesel” and sustainable aviation fuels. Transferring those currently-purchase fatty acids to a kraft pulp mill would allow that pulp mill to product LFA or LFAA which could then be fed to the refineries rather than the fatty acid. This would increase the fraction of “biofeed” to the refinery. For instance, one metric ton (Te) of fatty acid could be used to make over 1.8 Te of LFA or LFAA so that the biofeed to a refinery would be increased by more than 80%. However, the “yield” of green gasoline and diesel or sustainable aviation fuel must be determined by each oil company. (2) Asphalt companies could use LFA or LFAA as additives for asphalt. Asphalt companies could add dry powder lignin to asphalt, but they would strongly prefer to add a liquid, not a solid. Lignin does not biodegrade so that LFA or LFAA added to asphalt systems would sequester carbon indefinitely. Adding 30% lignin to all the asphalt used in the US each year -Docket No. 333-003WO about 30 million Tr / y would sequester more than 20 million Te / y equivalents of CO2. Also, currently “rejuvenates” which are petroleum fractions have to be added which allow the use recycled asphalt pavement (RAP). Those petroleum fractions could be replaced by LFA and LFAA. (3) Currently energy and carbon pellet manufacturers use relatively high quality and expensive com starch as lubricants to lengthen the lifetime of expensive dies and to bind the pellets better so less dust is generated during mechanical transport and storage. LFA or LFAA, which are designed to be a liquid at extrusion temperatures and a solid at storage / shipment temperature could replace corn starch which instead could be used in the food chain.

[0202] Regarding formation of lignin-biodiesel or fatty acid adducts; the following information provides details for biodiesel-lignin reactions. These reactions are tailored toward the identification of optimal reaction conditions for the binding of biodiesel moieties to lignin products derived from multiple sources. These materials could help increase the renewable content of petroleum-derived products, such as asphalt crack sealants, asphalts additives, and fuel precursors (e.g., unrefined fuel feedstocks). The primary goal of these reactions is to bind alkyl chains to lignin to make the lignin more soluble with the petroleum-based species found in asphalt and fossil fuels. By selecting the optimal number of alkyl chains and alkyl chain length, it should be possible to create a low-cost, modified lignin species with enhanced properties that could be used as a renewable filler in asphalt or fossil fuel blends or as a primary component of asphalts repair products.

[0203] Some sources for renewable extend-chain alkanes are bio-oils and biodiesel. Bio-oils can be used, but the resulting byproduct is glycerol, which is likely difficult to remove and there is little market demand for more glycerol currently. Alternatively, biodiesel offers many advantages because the ester groups can be used to esterify alcohol moieties on the various lignin monomers (e.g., creating the desired alkyl side chains), and the resulting methanol byproduct is easily removed and purified or reused to make more biodiesel. Such a reaction can be catalyzed at low temperatures by bases, such as NaOH or NaOCFL, but the presence of carboxylic acid groups in lignin presents a particular challenge with using the base-catalyzed route. As illustrated in Fig. 9, the alkyl bases form soaps with the lignin carboxylic groups as shown in reaction A, where RCOOH represents lignin). The lignin also has to be very dry (e.g., less than 1% water),Docket No. 333-003WO or reactions such as that shown in reaction B would convert the biodiesel, represented by RCOOMe into carboxylic groups that would also quickly become a soap species.

[0204] The acid-catalyzed route for esterification has been well studied. This approach often involves using a few percent of a strong homogeneous acid, such as sulfuric acid, to catalyze the desired esterification reactions. It is well known that the acid-catalyzed route proceeds at a slower rate than the base-catalyzed approach (e.g., up to 4000 times slower), but it avoids the formation of soaps (e.g., caused by use of a base catalyst), which tend to cause gel formation and many other problems for downstream separation processes. The slow kinetics of this reaction at room temperature can be overcome by raising the reaction temperature. For example, high conversions of fatty acids to biodiesel takes approximately 20 hours at 77 °C, 3 hours at 117 °C, but only 15 min at 240 °C. Depending on the vapor pressure of the particular biodiesel (or fatty acid) being used, the pressure of the reaction system may need to be increased above 1 atm to ensure the reaction mixture remains a liquid but this is likely not an issue (note that the boiling point of most biodiesel and lignin variants is above 300 °C).

[0205] In Fig. 11, the data shows the concentration of lignin groups that still have an OH functional group. This is not shown on the figure. Initial reaction efforts examined the reaction of partially dried lignin (e.g., approximately 10 % water) with varying amounts of biodiesel and an approximately 2-5 wt% loadings of sulfuric acid catalyst (based on the total weight of lignin and biodiesel). The resulting products were examined by Phosphorous NMR to determine the percentage of lignin alcohol groups that become esterified or transesterified during the reaction with biodiesel. Reacting phosphorous species with the OH species on lignin and then quantifying the type of resulting phosphorous species formed has been shown to be the best way to quantify the presence of OH species (carboxylic acid and alcohol OHs) in lignin. The liquid acid- catalyzed transesterification process does not currently enjoy the same popularity in commercial biodiesel applications as its counterpart, the base-catalyzed process. The fact that the homogeneous acid-catalyzed reaction is about 4000 times slower (at moderate temperatures) than the homogeneous base-catalyzed reaction has been the main reason. The problem with using the acid-catalyzed route with biodiesel production results from the need to raise the reaction temperature to speed up the reaction but given that one of the biodiesel reactants is methanol, such a temperature increase would require a significant increase in pressure to keep the methanolDocket No. 333-003WO in the liquid phase. Tn the reaction study, there are no high-volatility reagents involved in the reaction, so it is relatively easy to raise the reaction temperature to achieve excellent reaction rates, while still being able to operate at atmospheric pressures. The elevated reaction temperatures can also be used to drive these reversible reaction toward the desired ester products and volatilize any unwanted methanol (or water) byproducts from the lignin-biodiesel adduct, which is important for final-use applications.

[0206] At present, it is unknown if the degree of unsaturation (number of alkenes) of the fatty acid tethers attached to lignin will impact their short or long-term performance. For example, extended sun exposure of unsaturated acid tethers could alter their viscoelastic properties or lead to product degradation over time. The source of biodiesel (e.g., corn, soybean, peanut, etc.) can impact the distribution of fatty acid esters present in the biodiesel, which may ultimately affect the type of fatty acid tethers on the lignin. For example, com oil contains: 13% saturated fatty acids. 28% monounsaturated fatty acids (e.g., oleic acid), and 59% polyunsaturated acids (e.g., linoleic acid). Soybean oil has a similar distribution of saturated and unsaturated fatty acids; whereas peanut oil contains 58% monounsaturated fatty acids and coconut oil contains 83% saturated fatty acids. These initial studies will only examine corn or soybean oil-derived biodiesel.

[0207] Lignin is a strong absorber of UV-V irradiation (thus the dark color), which complicates the use of any light spectroscopy techniques (e.g., FTIR) for material characterization purposes. The diversity of hydroxyl and carboxylic acid species also makes oxygen elemental analysis largely useless. The variability of monomer and local structures in lignin also makes the characterization of carboxylic acid groups by titration techniques nearly impossible. These facts have led NMR Analysis to become the primary means for characterizing the functional groups present in ligand. Of particular importance is the relative amount of hydroxyl oxygens that react (vis nucleophilic attack) with biodiesel esters to form lignin ester products. Thus, quantification of the hydroxyl groups on lignin by NMR techniques is essential. It may initially be assumed that low-cost and simple 1H NMR methods would suffice, assuming a high-magnetic field NMR (500 MHz or higher) were used for the analysis, but the variability in lignin structure creates a ‘forest’ of peaks that are difficult to quantify. The solution to this problem is reacting the lignin hydroxyl groups with specialized phosphorus species to formDocket No. 333-003WO phosphorous-functionalized lignin groups. These phosphorous-functionalized oxygen species are much easier to identify and quantify. Methods for carrying out the phosphorous (31P) NMR are known. The methods react dried lignin with a reactive phosphorylating agent, 2-chloro-4, 4,5,5- tetramethyl-l,3-2-dioxaphospholane (TMDP), to form a host of different phosphorus groups and, importantly, these different phosphorus groups are easily quantified by31P NMR (not a ‘forest’ of peaks). This phosphorylating agent reacts aggressively with water, so lignin samples must be very dry and the TMDP reagent must be reacted with lignin in a nitrogen purged glove box. A mixture of pyridine and DMF (1:5.5 (vol / )) is often capable of fully dissolving most sulfonated lignins, but other solvents such as DM SO and THF may be used if a particular lignin-biodiesel sample is not well solubilized by the proposed DMF / pyridine mixture. To further enhance sample solubility, the lignin-biodiesel samples will be preswollen in DMSO overnight. Ultimately, a small amount of deuterated chloroform will be added as an internal standard for NMR analysis. All other required solvents will be nondeuterated.

[0208] Initial reaction studies were conducted in 350- or 500-ml glass flasks or a 2L stirred stainless steel Parr reactor fitted with a vent line. Initial small volume experiments were conducted in open-top 250- or 500-ml Erlenmeyer glass flasks and employed an overhead stirrer fitted with a Teflon agitator to ensure proper mixing of the reactants. The glass reaction system was maintained at the desired temperature (140 to 160 °C) using an electrically heated hot oil bath. In an example experiment, 50 g of partially dried (-10% moisture) lignin was added to 40 g of soy-derived biodiesel and 6.5 g of sulfuric acid in a 250 ml Erlenmeyer flask. The flask was constantly stirred using an overhead stirrer and heated to 160 °C using a hot oil bath. The initial mixture was a slurry of lignin in the biodiesel liquid. After 4 hours of reaction, the resulting product was cooled to room temperature. At room temperature, the products were a black solid that contained traces of unreacted biodiesel. When higher levels of biodiesel were added to the initial reaction mixture, greater amounts of unreacted biodiesel would be present in the final reaction product mixture, which tended to be a slurry. When excess biodiesel was added to the initial mixture, the unreacted biodiesel liquid layer in the final product was darkly colored (black), indicating that the modified lignin product had an appreciable solubility in the biodiesel liquid (which was not true for the starting lignin reactant).Docket No. 333-003WO

[0209] Referring now to Figs. 10-12, which show test results from phosphorous NMR analysis of modified-lignin products, for example, formed by a first reaction (e.g., reaction 1A). Fig. 11 shows results from NMR experiments. Figs. 10 and 12 indicate calculations to determine the ratio of reactants needed for the esterification reaction. Phosphorylated Lignin-Biodiesel adduct solids were dissolved in an NMR solvent mixture before analysis (pyridine, CHCF, DMF). Data shows that most lignin hydroxyl groups were converted to other species by reaction process #1 - likely fatty acid ester moieties. Acidic OH species (carboxylic acids) were unaffected by reaction process #1.

[0210] In one illustrative, experimental example, a 5-gram sample of the modified-lignin product formed by either first reaction 1A or reaction IB was heated to 110 °C under mixing in 5 grams of kerosene (purchased from Lowes). The kerosene-modified lignin mixture was stirred for 1 hr. Upon cooling to room temperature, a solid-liquid mixture was formed. The mixture was filtered, and the solid product was weighed to determine an estimate for the solubility of the modified-lignin product in kerosene, which is a property important for many renewable fuel and asphalt applications. Both the biodiesel and fatty acid-derived lignin products from reactions 1A and IB, respectively, showed similar solubilities in kerosene, approximately 19% solubility on a weight basis. These crude experiments are not meant to provide a critical answer as to product solubility but instead, provide a crude but promising estimate of the product solubility. It should be noted that the carboxylic acid groups of all of the tested samples were unreacted and likely lowered the solubility of the products in kerosene; thus, the need for reaction 2.

[0211] In a later set of experiments, some of the lignin-fatty acid ester product formed by the reaction shown in Fig. 1 was reacted with lauryl alcohol (e.g., reaction shown in Fig. 2). In these experiments, approximately 20 grams of lignin were reacted with 20 grams of lauryl alcohol using 5% of sulfuric acid as catalyst. The reaction mixture was heated to 170 °C for approximately 4 hours. Upon completion of the reaction, the mixture was cooled to room temperature. The final product mixture was a slurry that contained excess alcohol and a solid lignin containing product. These experiments included an excess of lauryl alcohol, and the unreacted alcohol liquid layer in the final product was darkly colored (black), indicating that the modified lignin product had an appreciable solubility in the alcohol liquid.Docket No. 333-003WO

[0212] The preceding detailed description refers to the accompanying drawings, which illustrate specific examples described by the present disclosure. Other examples having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same feature, element, or component in the different drawings. Throughout the present disclosure, any one of a plurality of items may be referred to individually as the item and a plurality of items may be referred to collectively as the items and may be referred to with like reference numerals. Moreover, as used herein, a feature, element, component, or step preceded with the word “a” or “an” should be understood as not excluding a plurality of features, elements, components, or steps, unless such exclusion is explicitly recited.

[0213] Illustrative, non-exhaustive examples, which may be, but are not necessarily, claimed, of the subject matter according to the present disclosure are provided above. Reference herein to “example” means that one or more feature, structure, element, component, characteristic, and / or operational step described in connection with the example is included in at least one aspect, embodiment, and / or implementation of the subject matter according to the present disclosure. Thus, the phrases “an example,” “another example,” “one or more examples,” and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example. Moreover, the subject matter characterizing any one example may be, but is not necessarily, combined with the subject matter characterizing any other example.

[0214] As used herein, a system, apparatus, device, structure, article, element, component, or hardware “configured to” perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, device, structure, article, element, component, or hardware “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, “configured to” denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware that enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system,Docket No. 333-003WO apparatus, device, structure, article, element, component, or hardware described as being “configured to” perform a particular function may additionally or alternatively be described as being “adapted to” and / or as being “operative to” perform that function.

[0215] Unless otherwise indicated, the terms "first," "second," “third,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and / or, e.g., a “third” or higher-numbered item.

[0216] As used herein, the phrase “at least one of,” when used with a list of items, means different combinations of one or more of the listed items may be used and only one of each item in the list may be needed. For example, “at least one of item A, item B, and item C” may include, without limitation, item A or item A and item B. This example also may include item A, item B, and item C, or item B and item C. In other examples, “at least one of’ may be, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; and other suitable combinations. As used herein, the term “and / or” and the “ / ” symbol includes any and all combinations of one or more of the associated listed items.

[0217] For the purpose of this disclosure, the terms “coupled,” “coupling,” and similar terms refer to two or more elements that are joined, linked, fastened, attached, connected, put in communication, or otherwise associated (e.g., mechanically, electrically, fluidly, optically, electromagnetically) with one another. In various examples, the elements may be associated directly or indirectly. As an example, element A may be directly associated with element B. As another example, element A may be indirectly associated with element B, for example, via another element C. It will be understood that not all associations among the various disclosed elements are necessarily represented. Accordingly, couplings other than those depicted in the figures may also exist.

[0218] As used herein, the term “approximately” refers to or represents a condition that is close to, but not exactly, the stated condition that still performs the desired function or achieves the desired result. As an example, the term “approximately” refers to a condition that is within an acceptable predetermined tolerance or accuracy, such as to a condition that is within 10% of theDocket No. 333-003WO stated condition. However, the term “approximately” does not exclude a condition that is exactly the stated condition. As used herein, the term “substantially” refers to a condition that is essentially the stated condition that performs the desired function or achieves the desired result.

[0219] Figs. 1 and 5-91, referred to above, may represent functional elements, features, or components thereof and do not necessarily imply any particular structure. Accordingly, modifications, additions and / or omissions may be made to the illustrated structure. Additionally, those skilled in the art will appreciate that not all elements, features, and / or components described and illustrated in Figs. 1 and 5-9, referred to above, need be included in every example and not all elements, features, and / or components described herein are necessarily depicted in each illustrative example. Accordingly, some of the elements, features, and / or components described and illustrated in Figs. 1 and 5-9 may be combined in various ways without the need to include other features described and illustrated in Figs. 1 and 5-9, other drawing figures, and / or the accompanying disclosure, even though such combination or combinations are not explicitly illustrated herein. Similarly, additional features not limited to the examples presented, may be combined with some or all of the features shown and described herein. Unless otherwise explicitly stated, the schematic illustrations of the examples depicted in Figs. 1 and 5-9, referred to above, are not meant to imply structural limitations with respect to the illustrative example. Rather, although one illustrative structure is indicated, it is to be understood that the structure may be modified when appropriate. Accordingly, modifications, additions and / or omissions may be made to the illustrated structure. Furthermore, elements, features, and / or components that serve a similar, or at least substantially similar, purpose are labeled with like numbers in each of Figs. 1 and 5-9, and such elements, features, and / or components may not be discussed in detail herein with reference to each of Figs. 1 and 5-9. Similarly, all elements, features, and / or components may not be labeled in each of Figs. 1 and 5-9. but reference numerals associated therewith may be utilized herein for consistency.

[0220] In Figs. 3 and 4A-4C, referred to above, the blocks may represent operations, steps, and / or portions thereof and lines connecting the various blocks do not imply any particular order or dependency of the operations or portions thereof. It will be understood that not all dependencies among the various disclosed operations are necessarily represented. Figs. 3 and 4A-4C and the accompanying disclosure describing the operations of the disclosed methods setDocket No. 333-003WO forth herein should not be interpreted as necessarily determining a sequence in which the operations are to be performed. Rather, although one illustrative order is indicated, it is to be understood that the sequence of the operations may be modified when appropriate. Accordingly, modifications, additions and / or omissions may be made to the operations illustrated and certain operations may be performed in a different order or simultaneously. Additionally, those skilled in the art will appreciate that not all the operations described need to be performed.

[0221] Further, references throughout the present specification to features, advantages, or similar language used herein do not imply that all of the features and advantages that may be realized with the examples disclosed herein should be, or are in, any single example. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an example is included in at least one example. Thus, discussion of features, advantages, and similar language used throughout the present disclosure may, but does not necessarily, refer to the same example.

[0222] The described features, advantages, and characteristics of one example may be combined in any suitable manner in one or more other examples. One skilled in the relevant art will recognize that the examples described herein may be practiced without one or more of the specific features or advantages of a particular example. In other instances, additional features and advantages may be recognized in certain examples that may not be present in all examples. Furthermore, although various examples of the system 200, the methods 1000 and 2000, and lignin-alkanoate product 100 have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.

Claims

Docket No. 333-003WOWhat is claimed is:

1. A method for producing a lignin-alkanoate product, the method comprising: mixing lignin and a fatty acid derivative to form a first slurry; reacting the first slurry according to first reaction conditions to form a crude lignin- alkanoate; and extracting a lignin-alkanoate product from the crude lignin-alkanoate according to first extraction conditions.

2. The method of Claim 1, wherein: the lignin is a solid having a moisture content of between 1% and 20 %; and the fatty acid derivative comprises one of a fatty acid or a fatty acid ester.

3. The method of Claim 1, wherein reacting the first slurry according to the first reaction conditions comprises: heating to a temperature of between approximately 80°C and 200°C; maintaining a pressure between approximately 0.1 atm and 2 atm; and adding a water-soluble catalyst.

4. The method of Claim 1, wherein: the crude lignin-alkanoate is a liquid crude lignin-alkanoate; and extracting the lignin-alkanoate product comprises: mixing the liquid crude lignin-alkanoate with a solvent to form a liquid lignin- alkanoate product; and removing the solvent.

5. The method of Claim 1, wherein: the crude lignin-alkanoate is a solid crude lignin-alkanoate; and extracting the lignin-alkanoate product comprises: mixing the solid crude lignin-alkanoate with a solvent to form a solid lignin- alkanoate product; andDocket No. 333-003WO removing the solvent.

6. The method of Claim 1, further comprising: mixing the crude lignin-alkanoate and alcohol to form a second slurry; reacting the second slurry according to second reaction conditions to form a crude alkyl lignin-alkanoate ester; and extracting an alkyl lignin-alkanoate ester product from the crude alkyl lignin-alkanoate ester according to second extraction conditions.

7. The method of Claim 6, wherein reacting the second slurry according to the second reaction conditions comprises: heating to a temperature of between approximately 80°C and 200°C; maintaining a pressure between approximately 0.1 atm and 2 atm; and adding a water-soluble catalyst.

8. The method of Claim 6, wherein: the crude alkyl lignin-alkanoate ester is a liquid crude alkyl lignin-alkanoate ester; and extracting the alkyl lignin-alkanoate ester product comprises: mixing the liquid crude alkyl lignin-alkanoate ester with a solvent to form a liquid alkyl lignin-alkanoate ester product; and removing the solvent.

9. The method of Claim 6, wherein: the crude alkyl lignin-alkanoate ester is a solid crude alkyl lignin-alkanoate ester; and extracting the alkyl lignin-alkanoate ester product comprises: mixing the solid crude alkyl lignin-alkanoate ester with a solvent to form a solid alkyl lignin-alkanoate ester product; and removing the solvent.

10. A lignin-alkanoate product produced according to the method of Claim 1 and comprising:Docket No. 333-003WO a lignin polymer on which hydroxyl functionalities have been reacted with a fatty acid to form ester bonds and water.

11. A lignin-alkanoate product produced according to the method of Claim 1 and comprising: a lignin polymer on which hydroxyl functionalities have been transesterified with a fatty acid ester to make a lignin-alkanoate and an alcohol byproduct.

12. A method for esterifying lignin, the method comprising: providing a fatty acid derivative; mixing lignin to the fatty acid derivative, wherein the lignin has between approximately 5% and approximately 25% water; forming a first slurry, comprising the fatty acid derivative, the lignin, and water; heating the first slurry to a first temperature of between approximately 80°C and approximately 200°C; holding the first slurry at the first temperature between approximately 2 hours and 10 hours; removing the water from the first slurry; forming a second slurry, comprising the fatty acid derivative and the lignin; mixing a water-soluble catalyst to the second slurry; removing the water while holding near the first temperature; forming a first reaction mixture, comprising the fatty acid derivative, the lignin, and the water-soluble catalyst: mixing the first reaction mixture; heating the first reaction mixture to a second temperature of between approximately 130°C and approximately 250 °C; holding the first reaction mixture at the second temperature; removing a vapor byproduct from the first reaction mixture; forming a first product mixture, comprising a lignin-alkanoate and the water-soluble catalyst; cooling the first product mixture to a third temperature of between approximately 80°C and approximately 120 °C;Docket No. 333-003WO holding the first product mixture at the third temperature; mixing wash water to the first product mixture; forming an extraction mixture, comprising the lignin-alkanoate, the water-soluble catalyst and wash water; holding the extraction mixture at the third temperature; one of: removing an aqueous solution from the extraction mixture; or decanting the lignin-alkanoate from the extraction mixture; forming an organic-rich raffinate phase, comprising the lignin-alkanoate and trace water; holding the organic-rich phase raffinate at the third temperature; applying vacuum to the organic -rich raffinate phase; removing the trace water; producing a water-free lignin-alkanoate; cooling the water-free lignin-alkanoate; and storing the water-free lignin-alkanoate.

13. The method of Claim 12, further comprising: mixing an alcohol to the first product mixture; forming a second reaction mixture, comprising the lignin-alkanoate, the water-soluble catalyst, the alcohol, and a water byproduct; heating the second reaction mixture to a fifth temperature from approximately 130 °C to 250 °C; holding the second reaction mixture at the fifth temperature; remove the water byproduct; and forming a second product mixture, comprising an alkyl lignin-alkanoate ester and the water-soluble catalyst; cooling the second product mixture to a sixth temperature of between approximately 8 0 °C and 120 °C; holding the second product mixture at the sixth temperature; mixing wash water to the second product mixture:Docket No. 333-003WO forming an extraction mixture, comprising the alkyl lignin-alkanoate ester, the water- soluble catalyst and the wash water; holding the extraction mixture at the sixth temperature: one of: removing an aqueous solution from the extraction mixture; or decanting the alkyl lignin-alkanoate ester from the extraction mixture; forming an organic -rich phase raffinate, comprising the alkyl lignin-alkanoate ester and the trace water; holding the organic-rich phase raffinate at the sixth temperature; applying vacuum to the organic -rich phase raffinate; removing trace water: producing a water-free alkyl lignin-alkanoate ester; cooling the water-free alkyl lignin-alkanoate ester; and storing the water-free alkyl lignin-alkanoate ester.

14. A method for esterifying lignin, the method comprising: forming a first slurry, comprising a fatty acid derivative, lignin, and water; removing the water from the first slurry to form a first reaction mixture, comprising the fatty acid derivative, the lignin, and a water-soluble catalyst; and heating the first reaction mixture to remove a vapor byproduct from the first reaction mixture and to form a first product mixture, comprising a lignin-alkanoate and the water-soluble catalyst.

15. The method of Claim 14, further comprising: separating the water-soluble catalyst from the lignin-alkanoate.

16. The method of Claim 14, further comprising: mixing an alcohol to the first product mixture to form a second reaction mixture, comprising the lignin-alkanoate, the water-soluble catalyst, the alcohol, and a water byproduct.

17. The method of Claim 16, further comprising:Docket No. 333-003WO removing a water byproduct from the second reaction mixture to form a second product mixture, comprising an alkyl lignin-alkanoate ester and the water-soluble catalyst.

18. The method of Claim 17, further comprising: separating the water-soluble catalyst from the alkyl lignin-alkanoate ester.

19. The method of Claim 14, wherein: the lignin is a solid having a moisture content of between 1% and 25 %; and the fatty acid derivative comprises one of a fatty acid or a fatty acid ester.

20. The method of Claim 14, wherein the water-soluble catalyst comprises one of an acid catalyst or a base catalyst.

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