Process and device for co-production of synthesis gas and green organic product through non-grain biomass fermentation

Abstract

The invention provides a process and a device for co-production of synthesis gas and green organic products by non-grain biomass fermentation, the non-grain biomass is subjected to pretreatment, enzymolysis and solid-liquid separation to obtain a sugar solution and residues, the sugar solution is fermented to prepare a fermentation product, the residues are subjected to pulping and pure oxygen or oxygen-enriched gasification to obtain crude synthesis gas, and the crude synthesis gas is subjected to secondary fermentation to obtain the green organic products. The purified product can be used as a product or can be further prepared into a green organic product; the slurry is used as the raw material, the stability and the fluidity are good, only the biomass slurry pump needs to be used for pumping the slurry into the gasification furnace, the power consumption and the heat energy consumption of drying, briquetting or granulation, carbonization, powder conveying, grinding and the like of traditional biomass gasification are omitted, and the technical route is low in power consumption and heat consumption, stable in raw material conveying, easy to operate and suitable for large-scale production. The process cost and the equipment investment cost are low; according to the method disclosed by the invention, green organic products or synthesis gas products with relatively high additional values are co-produced while green cellulosic ethanol and other fermented products are obtained, the products are more diversified, and the co-production advantage is obvious.

Description

Technical Field

[0001] The present invention belongs to the field of non-grain bio-based materials, and relates to a process and device for co-producing syngas and green organic products by fermenting non-grain biomass. Background Art

[0002] Traditional biomass gasification reactors include fixed beds, fluidized beds, entrained flow beds, etc., and currently all use dry feeding; among them, fixed bed gasification is suitable for raw materials with high reaction activity, but due to the extremely high volatile content and poor thermal stability of biomass, it is difficult to control the bed layer of the fixed bed; for fluidized bed gasification, in order to ensure the full reaction of the materials, the stability of the bed layer must be ensured, and the particle size of the feed is required to be small. Some fluidized bed technologies require heating media such as sand, resulting in greater operation difficulty, easy wear of the equipment, inability to produce stably, and higher use cost; for entrained flow bed gasification (dry method) technology, since the transportation of biomass powder is relatively difficult, and it is necessary to carry out briquetting and powder making and a large amount of carrier gas is required for transportation, the energy consumption is large.

[0003] The raw materials used in traditional biomass gasification processes need to undergo operations such as drying, briquetting or granulation, carbonization, powder transportation, and grinding. The process has high power consumption and heat consumption, and high production cost. Therefore, it is still of great significance to develop a process for co-producing syngas and other green organic products without operations such as drying, briquetting or granulation, carbonization, powder transportation, and grinding. Summary of the Invention

[0004] The purpose of the present invention is to provide a process and device for co-producing syngas and green organic products by fermenting non-grain biomass. Using non-grain biomass (or non-food-grade biomass) as the raw material, through pretreatment, enzymatic hydrolysis, and solid-liquid separation, sugar liquid and residues are obtained. The sugar liquid is fermented to prepare fermentation products, and the residues are made into slurry and gasified with pure oxygen or oxygen-enriched gas to obtain crude syngas, and then green organic products are prepared or syngas products are obtained after purification; using the above slurry as the raw material, the slurry has good stability and fluidity, and only needs to be pumped into the gasification furnace by a biomass slurry pump, with low power consumption and heat energy consumption, stable raw material transportation, easy operation, low process cost, and low equipment investment cost; and in the process, while obtaining fermentation products such as green cellulose ethanol, green organic products or syngas products with high added value can be obtained, the products are more diverse, and the co-production advantage is obvious.

[0005] To achieve the purpose of this invention, the following technical solutions are adopted in the present invention:

[0006] In the first aspect, the present invention provides a process for co-producing syngas and green organic products by fermenting non-grain biomass, including the following steps:

[0007] (1) Non-grain biomass is pretreated, enzymatically hydrolyzed, and solid-liquid separated to obtain sugar liquid and residues;

[0008] (2) Ferment the sugar solution obtained in step (1) to obtain a green fermentation product;

[0009] (3) Use the residue obtained in step (1) as a raw material to prepare a slurry; the concentration of the slurry is 30% - 80%, such as 35%, 40%, 35%, 50%, 55%, 60%, 65%, 70% or 75%, etc.

[0010] (4) Gasify the slurry obtained in step (3) with pure oxygen or oxygen - enriched gas to obtain raw syngas;

[0011] (5) Optionally, use the raw syngas obtained in step (4) as a raw material;

[0012] Prepare green methanol, ethanol, butanol or aviation kerosene through chemical reaction or fermentation;

[0013] And / or, obtain a syngas product after purification.

[0014] The process of the present invention uses non - grain biomass as a raw material. Through pretreatment, enzymatic hydrolysis, and solid - liquid separation, a sugar solution and a residue are obtained. The sugar solution is fermented to obtain biomass products, including green cellulose ethanol or butanol, etc. To solve the problem of residue treatment and improve the added value of the process, and at the same time solve the problem of high energy consumption in operations such as drying, briquetting or granulation, carbonization, powder conveying, and milling required in traditional biomass gasification processes, the present invention uses this residue as a raw material, prepares a slurry, and obtains a slurry with a concentration of 30% - 80% having good fluidity and stability, meeting the slurry concentration and particle size requirements for slurry - phase gasification, and uses the slurry as feedstock for gasification with pure oxygen or oxygen - enriched gas to obtain raw syngas, and then synthesizes green organic products (including but not limited to green methanol, ethanol, butanol or aviation kerosene, etc.); using the above process not only solves the problem of residue treatment, but also can obtain green syngas and green organic products as co - products, and the added value of the process is significantly improved; and the slurry prepared from the above residue in the present invention is used as the gasification raw material, with high calorific value of the raw material, saving the power consumption and heat energy consumption of traditional biomass gasification such as drying, briquetting or granulation, carbonization, powder conveying, milling, etc. and the power consumption of the carrier gas CO 2 The power consumption of the compressor.

[0015] The biomass gasification gas obtained in step (4) of the present invention mainly consists of CO and H 2 , and can be directly used as a product gas, or the biomass gasification gas can be further transformed, purified, methanol - synthesized and methanol - rectified to obtain green methanol meeting the first - class product standard, or other green products such as ethanol, butanol or aviation kerosene can be obtained through other chemical reactions or fermentation methods.

[0016] The execution order of step (2) and step (3) of the present invention is not limited.

[0017] The non-grain biomass includes any one or a combination of at least two of corn straw, corn cob, reed, giant reed, rice straw, rice husk, wheat straw, wheat husk, sugarcane tail, understory (referring to the vegetation and organisms below the tree canopy in the forest), or cow dung.

[0018] In the present invention, when the biomass raw material is selected as rice straw and / or rice husk, it has a relatively higher ash content and a larger amount of organic fertilizer produced.

[0019] Preferably, cellulase is used for enzymatic hydrolysis, the enzymatic hydrolysis temperature is 45°C to 55°C, such as 50°C, the pH is 4.8 to 5.0, and the solid content of the ingredient is 20% to 30%, such as 22%, 25%, or 28%, etc.

[0020] Preferably, the steps of the pretreatment include washing, crushing, and steam explosion.

[0021] Preferably, the green fermentation product includes green cellulose ethanol or butanol.

[0022] Preferably, the dry basis calorific value of the dried slurry is ≥9 MJ / kg, preferably ≥18 MJ / kg; such as 18.5 MJ / kg, etc. It has a higher calorific value compared to traditional biomass gasification raw materials.

[0023] Preferably, in the process of preparing the slurry in step (3), mechanical combined with bio-enzyme liquefaction pulping is adopted.

[0024] Here, the method of mechanical combined with bio-enzyme liquefaction pulping refers to the use of mechanical combined with bio-enzyme liquefaction in the process of preparing the slurry, that is, adding bio-enzyme to assist liquefaction. The bio-enzyme can be selected from composite bio-enzymes. The present invention does not limit the type of enzyme, as long as it can assist in achieving the liquefaction effect.

[0025] In the present invention, the process of enzymatic hydrolysis for sugar production can be selected from traditional processes of enzymatic hydrolysis for sugar production. For example, cellulase or other compound enzymes are used to perform enzymatic hydrolysis on non-grain biomass such as pretreated straw, and after solid-liquid separation, sugar solution and residues are obtained. The sugar solution is used for further biological fermentation to produce fermentation products, and the residues are used as gasification raw materials.

[0026] In the present invention, the residues generated during the fermentation process are used as gasification raw materials. Compared with traditional biomass gasification raw materials, some components with low calorific value are removed during the fermentation process, so that the residues have a higher calorific value than traditional gasification biomass raw materials, and have a higher effective gas production under the same feed amount.

[0027] Preferably, in step (4), the gasification process is slurry feeding.

[0028] Preferably, the reactor used in the gasification process is a entrained flow bed.

[0029] The residues in the non-grain biomass fermentation process contain components such as lignin.

[0030] Traditional biomass gasification is generally fixed-bed gasification, fluidized-bed gasification or entrained-flow bed gasification (dry powder), and the above processes are all dry feeding. The pretreatment of traditional biomass gasification is relatively complex, and the raw material transportation is difficult. The pretreated briquetted or granulated raw materials require relatively low moisture, while most biomass has a high water content. Therefore, drying needs to be set up, and entrained-flow bed and fixed-bed gasification require N 2 or CO 2 as the carrier gas, and the energy consumption of pretreatment and raw material transportation is relatively high.

[0031] In the gasification technology of the present invention, since the feeding is slurry feeding, the advantages of the slurry are good stability and good fluidity. It only needs to be pumped into the gasification furnace by a biomass slurry pump, with low power consumption, stable raw material transportation, and convenient and simple operation. In addition, the gasification ash treatment method is simple, only a scrubber is needed, and there is no need to set up the metal filter equipment required for entrained-flow bed (dry ash removal). Moreover, the produced biomass syngas has a high water-vapor ratio, and steam does not need to be replenished in the downstream shift section.

[0032] Preferably, in step (4), the gasification temperature is selected from 1100 °C to 1500 °C, such as 1200 °C, 1250 °C, 1300 °C, 1350 °C, 1400 °C or 1450 °C, etc.

[0033] Preferably, in step (4), the gasification pressure is selected from 0.5 MPa to 8.7 MPa, such as 3.5 MPa, 4 MPa, 4.5 MPa, 5.0 MPa, 6.5 MPa or 8.7 MPa, etc.

[0034] Preferably, the slag produced in the gasification process in step (4), after drying, obtains an organic fertilizer by-product.

[0035] In the present invention, the water content in the slag produced by gasification is about 40% - 60%. After further drying, an organic fertilizer by-product can be obtained, improving the project income.

[0036] Preferably, in step (4), the proportion of effective gas in the biomass syngas obtained after gasification of the slurry with pure oxygen or oxygen-enriched gas is 60% - 85%, such as 63%, 65%, 68%, 70%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80% or 83%, etc.

[0037] Here, the effective gas refers to H 2 and CO; by adopting the above process in the present invention, the content of effective gas is relatively high.

[0038] Preferably, in the syngas obtained by gasification in step (4),

[0039] Second aspect, the present invention provides a device for co-producing syngas and green organic products by non-grain biomass fermentation. The device includes:

[0040] A pretreatment enzymatic hydrolysis unit for preparing sugar solution and residues from non-grain biomass; and

[0041] A fermentation unit for fermenting the sugar solution to obtain green fermentation products; and

[0042] A slurry preparation unit for converting the residues into slurry; and

[0043] An gasification unit for gasifying the slurry to obtain syngas;

[0044] The liquid phase outlet and the solid phase outlet of the pretreatment enzymatic hydrolysis unit are respectively connected to the fermentation unit and the slurry preparation unit; the slurry preparation unit is connected to the gasification unit;

[0045] Optionally, it further includes a synthesis unit for converting the syngas into green organic products; the gasification unit is connected to the synthesis unit.

[0046] Optionally, the gasification unit is connected to the synthesis unit via a purification unit. When the gasification unit is connected to the synthesis unit, a purification unit or the like can be added in front of the synthesis unit as needed. Taking the methanol synthesis unit as an example, the raw syngas produced by the gasification unit needs to be transformed and purified to obtain syngas raw materials, and then enter the synthesis unit for methanol synthesis.

[0047] The pretreatment enzymatic hydrolysis unit includes a solid-liquid separation function.

[0048] In the present invention, "optionally" means that the raw syngas can either be used as the final product after purification, or be further transformed into green organic products such as green methanol, ethanol, butanol or aviation kerosene through processes such as reaction or fermentation after treatment (such as purification).

[0049] Preferably, the gasification unit adopts a slurry-fed entrained flow reactor.

[0050] By using the above device, the present invention can realize the resource utilization of the residues from non-grain biomass fermentation, obtain syngas and green organic products with high added value, and adopt the slurry-fed entrained flow gasification technology, which does not require briquetting, granulation and grinding, or grinding after low-temperature carbonization, saving a large amount of power consumption and heat energy consumption.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) Compared with traditional biomass gasification technology, the process of the present invention uses the residue obtained during the preparation of biomass products by non-grain biomass (non-food grade) fermentation method as raw material. After preparing slurry and using the slurry as the feed of the gasifier, the slurry has good stability and fluidity, and only needs to be pumped into the gasifier by a biomass slurry pump, thus saving the power consumption and heat energy consumption such as drying, briquetting or granulation, carbonization, powder conveying, and milling required for traditional biomass gasification, as well as the power consumption of the 2 CO compressor. This technical route has low power consumption and heat energy consumption, stable raw material transportation, easy operation, low process cost, and low equipment investment cost.

[0053] (2) The process of the present invention uses the residue of non-grain biomass fermentation method as raw material, and can co-produce syngas and other organic products with higher added value. The products are more diverse and the co-production advantage is obvious. Description of the Drawings

[0054] Figure 1 is the device flow chart in Embodiment 1 of the present invention;

[0055] Figure 2 is the process flow chart in Embodiment 1 of the present invention. Detailed Embodiments

[0056] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0057] The present invention provides a device for co-producing syngas and green organic products by non-grain biomass fermentation, as Figure 1 shown, the device includes:

[0058] A pretreatment enzymatic hydrolysis unit for preparing sugar solution and residue from non-grain biomass; and

[0059] A fermentation unit for fermenting the sugar solution to obtain green fermentation products; and

[0060] A slurry preparation unit for converting the residue into slurry; and

[0061] A gasification unit for gasifying the slurry to obtain syngas;

[0062] A synthesis unit for converting the syngas into green organic products;

[0063] The liquid phase outlet and solid phase outlet of the pretreatment enzymatic hydrolysis unit are respectively connected to the fermentation unit and the slurry preparation unit; the slurry preparation unit is connected to the gasification unit; the gasification unit is connected to the synthesis unit.

[0064] The gasification unit adopts a slurry-fed entrained flow reactor.

[0065] For the operation flow chart of the above device, see Figure 2 , the pretreatment enzymatic hydrolysis unit is used to perform operations such as pretreatment (including cleaning, crushing, and explosion puffing), enzymatic hydrolysis, and solid-liquid separation on non-grain biomass to obtain sugar liquid and residues; then the sugar liquid enters the fermentation unit for fermentation to obtain products such as green cellulose ethanol and butanol; the residues enter the pulping unit and are pulped to obtain a slurry with a concentration of 30-80%; the water content in the slurry is 20%-70%; then the slurry is pumped into the gasification unit by a biomass slurry pump and gasified to obtain syngas, and the syngas enters the synthesis unit and obtains green organic products such as green methanol through chemical reactions or fermentation.

[0066] Example 1

[0067] The present invention provides a process for co-producing syngas and green organic products by fermenting non-grain biomass, specifically including:

[0068] In this example, corn straw is used as the raw material, and after cleaning, crushing, explosion puffing, enzymatic hydrolysis, and solid-liquid separation, sugar liquid and residues are obtained;

[0069] In this example, cellulase is used for enzymatic hydrolysis, the enzymatic hydrolysis temperature is 50°C, and the pH is 4.8-5.0;

[0070] The obtained sugar liquid is fermented with active dry yeast, and after subsequent rectification, a green cellulose ethanol product with an alcohol content ≥95.5% is obtained, meeting the first-class product index;

[0071] The obtained residues are used as raw materials, and a slurry is prepared by biological enzyme liquefaction. The concentration of the slurry is 65%, the slurry has good fluidity, and the calorific value measured by a bomb calorimeter after drying is 18.9 MJ / kg;

[0072] The industrial analysis results of the dried slurry are shown in Table 1;

[0073] Table 1

[0074]

[0075] The particle size distribution D0.9 in the slurry is 57.867 microns;

[0076] The obtained slurry is pumped into a entrained flow gasifier by a biomass slurry pump for pure oxygen gasification. The gasification temperature is 1300°C; the gasification pressure is 4 Mpa to obtain a raw syngas product. The obtained gasification slag is used as organic fertilizer.

[0077] The composition of the obtained raw syngas (dry basis) is shown in Table 2 below; the carbon conversion rate ≥99%;

[0078] Table 2

[0079] Gas composition Typical value CO v% 41.89 <![CDATA[H 2 v%]]> 30.23 <![CDATA[N 2 +Ar v%]]> 0.61 <![CDATA[CO 2 v%]]> 27.03 <![CDATA[CH 4 ppmv]]> 1761

[0080] It can be seen from this that the present invention uses residues as raw materials, prepares slurries, and uses a slurry-fed entrained flow reactor. The proportion of effective gas components in the obtained syngas can reach more than 72%.

[0081] Preparation of green methanol: Using the obtained crude syngas product as a raw material, through shift conversion, purification, methanol synthesis, and rectification steps, green methanol meeting the first-class product standard can be obtained.

[0082] Example 2

[0083] The present invention provides a process for co-producing syngas and green organic products by non-grain biomass fermentation, specifically including:

[0084] In this example, rice straw is used as a raw material. After cleaning, crushing, steam explosion, enzymatic hydrolysis, and solid-liquid separation, sugar solution and residues are obtained;

[0085] In this example, cellulase is used for enzymatic hydrolysis, the enzymatic hydrolysis temperature is 50 °C, and the pH is 4.8 - 5.0;

[0086] The obtained sugar solution is fermented using active dry yeast, and after subsequent rectification, a green cellulose ethanol product with an alcohol content ≥ 95.5% is obtained, meeting the first-class product index;

[0087] Taking the obtained residues as raw materials, slurries are prepared by biological enzyme liquefaction. The concentration of the slurries is 65%, the slurries have good fluidity, and the calorific value measured by a bomb calorimeter after drying is 16.86 MJ / kg;

[0088] The obtained slurries are pumped into an entrained flow gasifier by a biomass slurry pump for pure oxygen gasification. The gasification temperature is 1280 °C; the gasification pressure is 4.2 Mpa, and a crude syngas product is obtained; the carbon conversion rate ≥ 99%;

[0089] The proportion of effective gas in the obtained crude syngas product is 77%. The obtained gasification slag is used as an organic fertilizer.

[0090] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A process for co-producing synthesis gas and green organic products by fermentation of non-food biomass, characterized in that: The following steps are involved: (1) Non-food biomass is subjected to pretreatment, enzymatic hydrolysis, and solid-liquid separation to obtain sugar solution and residue; (2) fermenting the sugar solution obtained in step (1) to obtain a green fermentation product; (3) using the residue obtained in step (1) as a raw material to prepare a slurry, wherein the concentration of the slurry is 30% to 80%; (4) gasifying the slurry obtained in step (3) with pure oxygen or oxygen-enriched oxygen to obtain a crude synthesis gas; (5) Optionally, the crude synthesis gas obtained in step (4) is used as a raw material; Green methanol, ethanol, butanol or aviation kerosene can be produced through chemical reaction or fermentation; And / or obtain synthesis gas product after purification.

2. The process according to claim 1, characterized in that The non-food biomass in step (1) includes any one of corn stalks, corn cobs, reeds, reed bamboo, rice stalks, rice husks, wheat stalks, wheat husks, sugarcane tails, forest understory or cow dung, or a combination of at least two of them.

3. The process according to claim 1 or 2, characterized in that The pretreatment steps in step (1) include cleaning, crushing and gas explosion.

4. The process according to claim 1 or 2, characterized in that The green fermentation product in step (2) includes green cellulosic ethanol or butanol.

5. The process according to claim 1 or 2, characterized in that: The dry basis calorific value of the slurry after drying in step (3) is ≥9MJ / kg.

6. The process according to claim 1 or 2, characterized in that The process of preparing the slurry in step (3) adopts mechanical combined with biological enzyme liquefaction to prepare the slurry.

7. The process according to claim 1, characterized in that The gasification process in step (4) is slurry feed; The reactor used in the gasification process is an entrained flow reactor.

8. The process according to claim 7, characterized in that The gasification temperature in step (4) is selected from 1100° C. to 1500° C.; The gasification pressure in step (4) is selected from 0.5 MPa to 8.7 MPa.

9. The process according to any one of claims 1, 7-8, characterized in that: The slag produced in the gasification process in step (4) is dried to obtain an organic fertilizer by-product.

10. The process according to any one of claims 1, 7-8, characterized in that: In step (4), the effective gas in the biomass gasification gas obtained after the slurry is gasified with pure oxygen or oxygen-enriched gas accounts for 60% to 85%.

11. A device for co-producing synthesis gas and green organic products by fermentation of non-food biomass, characterized in that: The device comprises: A pretreatment enzymatic hydrolysis unit for preparing sugar solution and residue from non-food biomass; and A fermentation unit for fermenting sugar solution to obtain green fermentation products; and a pulping liquor unit for converting the residue into pulp; and A gasification unit for gasifying the slurry to obtain synthesis gas; and The liquid phase outlet and the solid phase outlet of the pretreatment enzymolysis unit are connected to the fermentation unit and the pulping liquid unit respectively; the pulping liquid unit is connected to the gasification unit; Optionally, it also includes a synthesis unit for converting synthesis gas into green organic products; the gasification unit is connected to the synthesis unit; The gasification unit adopts a slurry-fed entrained flow reactor.

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