Method and system for producing an oil-rich fraction from biomass - Patents.com

Abstract

The present invention relates to a method for producing an oil-rich fraction (OF) from a primary feedstock (FS) comprising water, a first salt, a second salt, and biomass. The feedstock (FS) is provided to a first reaction zone (Z1) of a conversion reactor (100), and the primary feedstock is allowed to react in the first reaction zone at a temperature of at least 350°C and a pressure of at least 160 bar to form a converted primary feedstock. The method includes separating a first salt-rich fraction (SF1), a second salt-rich fraction (SF2), and an oil-rich fraction (OF) from the converted primary feedstock. The method includes withdrawing the oil-rich fraction (OF) from the first reaction zone (Z1) and withdrawing the first salt-rich fraction (SF1) and the second salt-rich fraction (SF2) from the conversion reactor (100). In the method, the first salt-rich fraction (SF1) comprises at least a portion of a first salt that is dissolved in water, and the second salt-rich fraction (SF2) comprises at least a portion of a second salt in solid form, and at least one of the first salt and the second salt is a salt that is capable of reacting the biomass of the primary feedstock (FS) with the water of the primary feedstock (FS) to produce an oil-rich fraction (OF). A device for the same.

Description

[Technical field]

[0001] The present invention relates to a method and device for producing liquid bio-oil. Bio-oil can be produced from a feedstock containing biomass. The present invention relates to a method and device for producing high quality bio-oil, which is widely applicable, for example, as a replacement for fossil fuels and / or as a feed for biochemical production. [Background technology]

[0002] Bio-based materials have received great interest as replacements for fossil-based materials in the fuel and chemical industries. Bio-based oil (hereinafter bio-oil) can be produced from biomass in processes known per se. Such processes include thermal treatment of biomass, possibly in the presence of water, steam and / or catalysts, and recovery of the reaction products.

[0003] However, often the quality of bio-oil is not optimal. For example, the oxygen content of bio-oil may be too high. This affects the calorific value as well as the stability of bio-oil, because the oxygen in bio-oil tends to react during storage. In addition, sometimes there is a high content of impurities, including elements from groups 1 and 2 of the IUPAC periodic table of elements as well as other metals. This affects the refining possibilities of bio-oil, because such impurities may prevent the use of catalysts to purify bio-oil. In biomass, such impurities are often present in the form of a salt or salts. Summary of the Invention

[0004] It has been found that salts can be used as catalysts to catalyze the reaction of biomass with water to produce bio-oil at supercritical or near-critical process conditions. However, as mentioned above, salts are impurities of bio-oil. It has also been found that salts are not very soluble in water at supercritical or near-supercritical conditions. Thus, it has been found that at these process conditions the salts can be relatively easily separated from the rest of the feedstock. In particular, it has been found that the first type of salt, which is mostly soluble, can be withdrawn from the process as a first salt-rich fraction such as a solution, and the second type of salt, which is mostly insoluble, can be withdrawn from the process in a second salt-rich fraction in solid form. Thus, after completion of the biomass conversion reaction to bio-oil, the two salt-rich fractions can be withdrawn from the process to produce a cleaner bio-oil. Furthermore, withdrawing a portion of the second salt in solid form has the effect that these salts do not solidify in the reactor. Thus, blocking of the reactor is prevented. Furthermore, it becomes feasible to recycle the salt or salts back into the process for use as a catalyst and / or to recover materials from the salt or salts. Thus, a process is described that produces reasonably high quality bio-oil, [A] in terms of oxygen content by using the salt as a catalyst, and [B] in terms of purity by removing the salt from the process.

[0005] The process is described in more detail in independent claim 1. The claims and the description dependent on claim 1 disclose preferred embodiments. A corresponding system is described in more detail in independent claim 13. The claims and the description dependent on any of them disclose preferred embodiments. [Brief description of the drawings]

[0006] [Figure 1a] A method for producing an oil-rich fraction from biomass is described. [Figure 1b] A process for producing an oil-rich fraction from biomass is described in which the feedstock is superheated. [Figure 1c] A method is described to produce liquid bio-oil by cooling the oil-rich fraction. [Figure 1d] A method for producing liquid bio-oil is described in which a feed oil is heated. [Figure 1e] A method for producing liquid bio-oil is described in which a feed oil is heated. [Diagram 2] A method for producing liquid bio-oil is described in which a feedstock is formed by mixing its different components, which may contain dissolved and / or solid salts. [Figure 3a] A method for producing liquid bio-oil is presented in which an oil-rich fraction is catalytically converted into reaction products. [Figure 3b] A method for producing liquid bio-oil is presented in which an oil-rich fraction is catalytically converted into reaction products. [Figure 3c] A method for producing liquid bio-oil is presented in which an oil-rich fraction is catalytically converted into reaction products. [Figure 3d] A method for producing liquid bio-oil is presented in which an oil-rich fraction is catalytically converted into reaction products. [Figure 3e] A process is described in which an oil-rich fraction is catalytically converted into reaction products. [Figure 4a] Methods for producing liquid bio-oil and purifying the bio-oil so produced are described. [Figure 4b] Methods for producing liquid bio-oil and purifying the bio-oil so produced are described. [Figure 4c] Methods for producing liquid bio-oil and purifying the bio-oil so produced are described. [Figure 5a] A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 5b] A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 5c]A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 5d] A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 5e] A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 5f] A method is described for producing liquid bio-oil and recovering and using heat during the process. [Figure 6a] The use of a crystallizer to form a salt in crystalline form that may be removed as part of a second salt-enriched fraction is described. [Figure 6b] The use of a crystallizer to form a salt in crystalline form that may be removed as part of a second salt-enriched fraction is described. [Figure 6c] The use of a crystallizer to form a salt in crystalline form that may be removed as part of a second salt-enriched fraction is described. [Figure 7] 1 shows a method for crystallizing salt onto particles. [Figure 8] The integration of the method with the recovery of cooking chemicals in a chemical recovery boiler is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] FIG. 1a shows a method for producing an oil rich fraction from a biomass. In this method, a primary feedstock FS is provided to a first reaction zone Z1 of a conversion reactor 100. The first reaction zone Z1 is a space in the conversion reactor 100 in which the conversion of the primary feedstock FS to chemically different compounds takes place. The primary feedstock FS includes water, salts, and biomass, these terms being explained in more detail below. At least one of the salts catalyzes the conversion of the biomass to hydrocarbons for bio-oil. In this way, the salt acts as a catalyst and may be referred to as a homogeneous catalyst. The term homogeneous catalyst refers to a catalyst in which at least a part of the catalyst is dissolved in the primary feedstock FS. Thus, the catalyst and the primary feedstock FS are in the same phase (liquid and / or vapor and / or supercritical). Since the catalyst is a homogeneous catalyst, the salt acting as catalyst may in particular be a salt of the first salt rich phase as detailed below.

[0008] It has been found that salts catalyze the conversion reaction at least when the process conditions are supercritical or near supercritical. The term supercritical is used with respect to the critical point of water (i.e., a temperature of 374° C. and a pressure of 22 MPa, i.e., 220 bar). The conversion reaction is typically reasonably fast. More specifically, a reaction time t of at least 5 minutes is typically sufficient. Thus, in the present method, the primary feedstock FS is allowed to react in the first reaction zone Z1 at a temperature T of at least 350° C., for example, from 350° C. to 450° C., and at a pressure p of at least 160 bar. In one embodiment, the primary feedstock FS is allowed to react in this environment for a reaction time t of at least 5 minutes. Having a higher pressure does not prevent the conversion reaction from taking place. However, from the point of view of the manufacture of a suitable conversion reactor 100, it is preferred that the pressure p is between 160 bar and 350 bar. Furthermore, having a longer reaction time does not usually deteriorate the properties of the conversion product, but detrimental secondary reactions, such as carbonization and repolymerization, may occur. However, from an efficient production point of view, too long a reaction time must be avoided. Thus, in one embodiment, the primary feedstock FS is allowed to react in the first reaction zone Z1 at a temperature T between 350° C. and 450° C. and a pressure p between 160 bar and 350 bar for a reaction time t between 5 min and 30 min.

[0009] As shown in the background, from the perspective of the quality of the bio-oil, the bio-oil should not contain significant amounts of salts of the primary feedstock FS. It has been found that at these process conditions the solubility of salts in the feedstock water is reduced to a significant extent. Thus, at these process conditions it is possible to separate a first salt-rich fraction SF1, a second salt-rich fraction SF2 and an oil-rich fraction OF from the primary feedstock FS, i.e. the conversion product of the primary feedstock FS after conversion. Thus, an embodiment includes separating the first salt-rich fraction SF1, the second salt-rich fraction SF2 and the oil-rich fraction OF from the converted primary feedstock FS at a temperature between 350° C. and 450° C. and at a pressure of at least 160 bar. The pressure at which the separation is carried out may be, for example, between 160 bar and 350 bar. The temperature and pressure at which the separation is carried out may be the same as in the conversion reaction. Removing both salt-rich fractions SF1 and SF2 improves the quality of the bio-oil. In this way, an oil-rich fraction OF is produced.

[0010] Regarding the first and second salt-rich fractions SF1 and SF2, the first salt-rich fraction SF1 contains the first salt dissolved in the water of the feedstock FS, and the second salt-rich fraction SF2 contains the second salt in solid form. In general, the first salt may be a salt generally referred to as type 1 salt, and the second salt may be a salt generally referred to as type 2 salt. The solubility of type 2 salts decreases more rapidly as a function of increasing temperature at or near supercritical conditions than that of type 1 salts. In general, type 1 salts exhibit a continuous solubility curve at the supercritical temperature that does not cross the critical curve, whereas type 2 salts represent an intersection of the solubility curve and the critical curve, resulting in two critical endpoints in this region. More information on these two different types of salts can be found further in non-patent document 1.

[0011] Thus, type 2 salts tend to crystallize and / or form aggregates at these process conditions, while type 1 salts tend to form brines. Thus, type 1 salts condense and type 2 salts crystallize at these conditions. Typically, type 2 salts form sticky precipitates that easily adhere to the surfaces of the conversion reactor 100 and can cause blocking of the conversion reactor 100. Thus, removal of the second salt-rich fraction SF2 prevents blocking of the conversion reactor 100. Type 1 salts include NaCl, KCl, K2CO3, MgCl2, and CaCl2. Type 2 salts include MgCO3, MgSO4, CaCO3, CaCO4, Na2CO3, Na2SO4, Na3PO4, KSO4, and SiO2. However, these characterizations are also applicable to solutions with a single salt. In the case of salt mixtures, complex reactions can occur at near-supercritical conditions. For example, Na3PO4 and K2SO4 are normally type 2 salts, but in mixtures they can form K3PO4 and Na2SO4, which are type 1 and type 2 salts, respectively.

[0012] In one embodiment, the second salt-rich fraction SF2 contains type 2 salt. The aforementioned blocking problem can be avoided by solidifying the type 2 salt in the second salt-rich fraction SF2. The type 2 salt is solidified and removed from the conversion reactor 100 so that it does not clog the inner walls of the conversion reactor 100. An example of a specific means for solidifying the type 2 salt is presented later. Preferably, most of the salt is withdrawn from the conversion reactor 100 in the salt-rich fractions SF1 and SF2. In this way, the oil-rich fraction OF contains only little salt (if any). Thus, in one embodiment, at most 5% of the salt (type 1 salt and type 2 salt) fed into the conversion reactor 100 is withdrawn from the conversion reactor 100 in the oil-rich fraction OF. Obviously, the remaining salt is withdrawn in fractions SF1 and SF2.

[0013] In particular, when using black liquor as the feedstock FS, the type 1 salts involved in the process include NaCl, KCl, MgCl2, and CaCl2, and the type 2 salts involved in the process include MgCO3, Mg S O4, CaCO3, CaCO4, Na2CO3, Na2SO4, and K2SO4.

[0014] In general, the salt-rich fractions SF1 and SF2 are more concentrated (kg / m) than the oil-rich fraction OF. 3 The salt-rich fractions SF1 and SF2 have a high density (as measured by gravity) from the converted primary feedstock FS. Thus, the salt-rich fractions SF1 and SF2 may be separated from the converted primary feedstock FS, for example, by any means suitable for separating liquids with different densities. Such methods include centrifugation methods and gravity-based methods. Preferably, the first salt-rich fraction SF1 is separated from the converted primary feedstock FS by gravity. Preferably, the second salt-rich fraction SF2 is separated from the converted primary feedstock FS by gravity. Thus, the first salt-rich fraction SF1 may be withdrawn from a first point of the conversion reactor 100, which may be at a lower vertical level than the point from which the oil-rich fraction OF (or its reaction product RP) is withdrawn. Additionally or alternatively, the second salt-rich fraction SF2 may be withdrawn from a second point of the conversion reactor 100, which may be at a lower vertical level than the point at which the oil-rich fraction OF (or its reaction product RP) is withdrawn. Further, the second salt-rich fraction SF2 may be withdrawn from a second point of the conversion reactor 100, which may be at a lower vertical level than the first point at which the first salt-rich fraction SF1 is withdrawn.

[0015] At least a portion of the first salt-rich fraction SF1 may be recycled to be used as a catalyst. Thus, an embodiment includes feeding at least a portion of the first salt-rich fraction SF1 to the first reaction zone Z1 of the conversion reactor 100. Such an embodiment is shown, for example, in FIG. 2. At least a portion of the second salt-rich fraction SF2 may be recycled to be used as a catalyst. Thus, an embodiment includes feeding at least a portion of the second salt-rich fraction SF2 to the first reaction zone Z1 of the conversion reactor 100. Such an embodiment is shown, for example, in FIG. 2. When at least a portion of the salt-rich fractions SF1, SF2 are recycled, a heater 130 (heater) may be used to heat the corresponding salt-rich fraction (see FIG. 2). Furthermore, the heater 130 may be used to heat the recycled salt-rich fraction to near the supercritical temperature. As mentioned above, in such cases, the type 2 salts may solidify, thereby causing them to clog the heater 130. Accordingly, one embodiment includes recycling at least a portion of the first salt-rich fraction SF1. This embodiment may include heating the recycled first salt-rich fraction SF1 in the heater 130. However, the heater 130 need not heat the recycled salt-rich fraction, as shown in Figures 1b, 1d and 1e.

[0016] In particular, referring to FIG. 8, when the feedstock FS comprises black liquor BL, the salts of the salt-rich fractions SF1 and / or SF2 may be fed to a chemical recovery boiler 500 in order to recover cooking chemicals from these salts. The chemical recovery boiler 500 can be seen as part of a chemical recovery cycle configured to recover cooking chemicals. Thus, in one embodiment, the primary feedstock FS comprises black liquor BL, and the method comprises feeding at least a portion of the first salt-rich fraction SF1 to a chemical recovery cycle configured to recover cooking chemicals, for example to a chemical recovery boiler 500 configured to burn black liquor. Furthermore, in one embodiment, the primary feedstock FS comprises black liquor BL, and the method comprises feeding at least a portion of the second salt-rich fraction SF2 to a chemical recovery cycle configured to recover cooking chemicals, for example to a chemical recovery boiler 500 configured to burn black liquor. Such an embodiment is shown in FIG. 8. 8 shows that only the second salt-rich fraction SF2 is fed to the recovery boiler 500, both salt-rich fractions SF1, SF2 may be fed to the recovery boiler 500, and neither the first fraction SF1 nor the second fraction SF2 need be fed to the recovery boiler 500. Note that when the feedstock FS includes black liquor, typically the cooking chemicals are type 2 salts. Thus, in such an embodiment, at least a portion of the second salt-rich fraction SF2 is preferably fed to a chemical recovery boiler 500 configured to burn black liquor.

[0017] Furthermore, as can be read from above, type 1 salts include salts containing chlorine (Cl) and salts containing potassium (K). When applying the process in combination with a chemical recovery boiler 500, such salts are preferably not recovered in the boiler 500, since the cooking stage of the Kraft process does not require such cooking chemicals. In contrast, the majority of the cooking chemicals to be recovered are in the form of type 2 salts. Furthermore, chlorine can present corrosion problems for equipment. Therefore, in such a context, it is beneficial to feed only type 2 salts (i.e. the fraction rich in the second salt SF2) to a chemical recovery cycle configured to recover cooking chemicals, such as the chemical recovery boiler 500, and to otherwise use type 1 salts (i.e. the fraction rich in the first salt SF1), for example by returning at least a part of them to the process where they are used as a catalyst for biomass conversion, as shown in FIG. 8.

[0018] Although not shown in the figure, at least a portion of the first salt-rich fraction SF1 and / or at least a portion of the second salt-rich fraction SF2 may be supplied to the first process zone Z1 (see FIG. 2), even if at least a portion of the second salt-rich fraction SF2 is supplied to the chemical recovery boiler 500 (FIG. 8).

[0019] Additionally, when black liquor BL is used as the feedstock FS, a portion of the same black liquor may be combusted in the recovery boiler 500. Thus, one embodiment includes receiving black liquor, splitting the black liquor into a first portion (arrows "BL, FS" in FIG. 8) and a second portion (upper BL arrow in FIG. 8), conveying the first portion into the conversion reactor 100, and conveying the second portion into the chemical recovery boiler 500.

[0020] Referring to Figures 1a-1e, an oil-rich fraction OF is withdrawn from the first reaction zone Z1. As described in more detail below, the oil-rich fraction OF may be further reacted in a second reaction zone Z2 located in the same conversion reactor 100. The oil-rich fraction OF may be withdrawn from the conversion reactor 100. As described in more detail below, the oil-rich fraction OF may be further reacted in a second reaction zone Z2 located in another reactor 200. A first salt-rich fraction SF1 is withdrawn from the conversion reactor 100. A second salt-rich fraction SF2 is withdrawn from the conversion reactor 100. In this manner, an oil-rich fraction OF may be produced, as shown in Figures 1a and 1b.

[0021] In one embodiment, the oil-rich fraction OF is cooled to produce a liquid bio-oil, indicated as "OIL" in the figures (except for Figures 1a, 1b and 3e). The cooling causes at least a portion of the bio-oil in the oil-rich fraction OF to condense to a liquid. In one embodiment, the oil-rich fraction OF is cooled (and condensed) to produce a liquid bio-oil, indicated as "OIL" in Figures 1c-1e, without the oil-rich fraction being converted (by chemical reaction) to a reaction product RP prior to said cooling. In one embodiment, the oil-rich fraction OF is first converted (by chemical reaction) to a reaction product RP, which is cooled (and condensed) to produce a liquid bio-oil, indicated as "OIL" in Figures 3a-3d. Thus, one embodiment of the method comprises cooling the oil-rich fraction OF or the reaction product RP of the oil-rich fraction OF to produce a liquid bio-oil OIL. It is also possible to not convert part of the oil-rich fraction OF, but to convert part of the oil-rich fraction OF into the reaction product RP and to condense both the oil-rich fraction OF and the reaction product RP. As shown in Figure 3e, the reaction product RP does not have to be cooled. The reaction product RP may be cooled, as shown in Figures 3a to 3d.

[0022] Since the temperature and pressure in the first reaction zone Z1 are moderately high, the primary feedstock FS may be heated. Referring to FIG. 1b, FIG. 1d and FIG. 1e, a heater 130 may be used to heat the primary feedstock FS. The heater 130 may be disposed before the conversion reactor 100 as in FIG. 1b and FIG. 1d, and / or the heater 130 may be disposed inside the conversion reactor 100 as in FIG. 1e. Furthermore, even if not shown, the heater 130 may heat the conversion reactor 100 to heat the primary feedstock FS in the conversion reactor 100. Preferably, the heater 130 includes a heat exchanger 115 configured to transfer heat from at least one of the oil-rich OF and the reaction product RP to the primary feedstock FS (see FIG. 5a-FIG. 5f). In such an embodiment, the system may include a second heater 130′. The second heater 130' may be used to heat the primary feedstock FS. The second heater 130' may be disposed before the conversion reactor 100 (FIG. 5b), or the second heater 130 may be disposed inside the conversion reactor 100 (FIG. 5c). Furthermore, although not shown, the second heater 130' may heat the conversion reactor 100 to heat the primary feedstock FS in the conversion reactor 100. A pump 120 is provided to supply the primary feedstock FS to the conversion reactor 100, i.e., at high pressure (see FIGS. 1b, 1d, and 1e, as well as 5a-5f).

[0023] The heater 130 (and / or the second heater 130') may be configured to heat the primary feedstock FS at a rate of at least 50° C. / min, and preferably at a rate of at least 75° C. / min.

[0024] 1a-1e, a system for producing an oil-rich fraction (OF) from biomass includes a conversion reactor 100. As mentioned above, the conversion reactor 100 is configured to allow a primary feedstock FS to react in a first reaction zone Z1 at a pressure of at least 160 bar and at a temperature of at least 350° C., such as 350° C.-450° C. Due to the high pressure and temperature, this implies constraints on the materials of the conversion reactor 100 and their thickness. The conversion reactor 100 includes a first inlet 101 for allowing the primary feedstock FS to enter into the first reaction zone Z1, a first outlet 103 for allowing a first salt-rich fraction SF1 to exit the conversion reactor 100, a second outlet 104 for allowing a second salt-rich fraction SF2 to be taken from the conversion reactor 100, and a third outlet 105 for allowing at least one of the oil-rich fraction OF and the reaction product RP of the oil-rich fraction to exit the conversion reactor 100. For example, in the embodiments of Figures 1c-1e and 3a-3b, the third outlet 105 is for allowing the oil-rich fraction OF to exit the conversion reactor 100. For example, in the embodiments of Figures 3c and 3d, the third outlet 105 allows the reaction product RP of the oil-rich fraction OF to exit the conversion reactor 100.

[0025] Further, the conversion reactor 100 is configured to separate the first and second salt-rich fractions SF1 and SF2 and the oil-rich fraction OF from the converted primary feedstock FS at a temperature of at least 350°C, such as 350°C to 450°C, at a pressure of at least 160 bar. For example, the conversion reactor 100 may include a centrifuge (not shown) configured to separate at least one of the salt-rich fractions SF1 and SF2 and the oil-rich fraction OF from the converted primary feedstock FS. For example, a first centrifuge may separate two fractions, namely, [a] a fraction including the first and second salt-rich fractions SF1 and SF2, and [b] an oil-rich fraction. Thereafter, another centrifuge may be configured to separate the salt-rich fractions SF1 and SF2 from each other. Preferably, the conversion reactor 100 is configured to separate the salt-rich fractions SF1 and SF2 and the oil-rich fraction OF from the converted primary feedstock FS by gravity. In such an embodiment, the first outlet 103 is located at a lower vertical level than the third outlet 105 and the second outlet 104 is located at a lower vertical level than the third outlet 105. Furthermore, the second outlet 104 may be located at a lower vertical level than the first outlet 103.

[0026] In addition, the system includes a pump 120 configured to pump the primary feedstock FS through the first inlet 101 into the first reaction zone Z1 having a pressure of at least 160 bar. Since the pressure is moderately high, the pump 120 must be selected accordingly. When higher pressures are used, or at least higher pressures can be used, the pump 120 is configured to pump the primary feedstock FS through the first inlet 101 into the first reaction zone Z1 having a pressure of at least 220 bar, or at least 300 bar, or 350 bar.

[0027] Additionally, the system includes a heater 130 configured to heat the primary feedstock FS and / or the conversion reactor 100 such that the temperature in the first reaction zone Z1 is at least 350°C, such as between 350°C and 450°C. In one embodiment, the heater 130 is configured to heat the primary feedstock FS to a temperature of 350°C, such as between 350°C and 450°C. Preferably, the system includes a heater 130 configured to heat the primary feedstock FS and / or the conversion reactor 100 such that the temperature in the first reaction zone Z1 is between 375°C and 450°C. More preferably, the heater 130 is configured to heat the primary feedstock FS to a temperature of between 375°C and 450°C.

[0028] Further, referring to Figures 1c-1e, an embodiment of the system includes a cooler 110 (cooler) configured to cool at least one of the oil-rich fraction OF and the reaction product RP of the oil-rich fraction OF to produce a liquid bio-oil OIL. In addition, the system includes a pipeline 112 for conveying at least one of the oil-rich fraction OF and the reaction product RP to the cooler 110. In such a case, the system is for producing a liquid bio-oil ("OIL"). However, as shown in Figures 1a and 1b, the system does not need to include the cooler 110, especially when the system is for producing an oil-rich fraction ("OF").

[0029] For example, in the embodiment of Figures 1c-1e, the pipeline 112 is configured to convey the oil-rich fraction OF from the conversion reactor 100 to the cooler 110. For example, in the embodiment of Figures 3c and 3d, the pipeline 112 is configured to convey the reaction product RP from the conversion reactor 100 to the cooler 110. For example, in the embodiment of Figures 3a and 3b, the pipeline 112 is configured to convey the reaction product RP from the catalytic reactor 200 to the cooler 110.

[0030] As mentioned above, the primary feedstock FS includes water, salts, and biomass. The term biomass encompasses materials that naturally contain some water. Thus, the water content of the primary feedstock FS does not require added water. However, often some water is added.

[0031] The term "water" may also refer to steam. The water content of the primary feedstock may be at least 25% by weight, which has been found to be sufficient for the conversion reactions in the first reaction zone Z1. Thus, in one embodiment, the dry matter content of the primary feedstock FS is at most 75% by weight. The dry matter content of the primary feedstock FS may be between 20% and 75% by weight, preferably between 30% and 70% by weight.

[0032] The term "biomass" refers to material of biological origin. Biomass may include raw materials and waste products of plant, animal and / or fish origin or microbial origin, such as solid or semi-solid organic residues of anaerobic or aerobic digestion, such as logs, wood residues, forest residues, waste products, municipal waste products, industrial waste products or by-products, agricultural waste products or by-products, wood processing industry residues or by-products, food industry waste products or by-products, residues from biogas production from lignocellulosic and / or municipal waste products, residues from bioethanol production processes, and any combination thereof. Suitably, biomass includes waste products and by-products of the wood processing industry, such as slash, municipal wood waste, wood waste, wood chips, wood waste, sawdust, straw, firewood, wood materials, paper, by-products of paper making or wood processes, where biomass (plant biomass) is composed of at least hemicellulose and lignin. Biomass may further include cellulose. However, the cellulose fibers of the wood may be removed for other purposes and the remaining biomass may constitute the primary feedstock biomass.

[0033] The method is particularly suitable when a by-product or by-products of the pulp or paper industry, including black liquor of the Kraft process and brown liquor of the sulfite process, are used as the primary feedstock FS, since these by-products also contain many salts and biomass, which naturally contain lignin residues and hemicellulose. The salts act as catalysts in the conversion of the feedstock to bio-oil. Typically, the dry matter content of such liquids is between 30% and 40% by weight. Thus, in one embodiment, the biomass comprises at least one of lignin and hemicellulose. In one embodiment, the biomass comprises at least one of lignin and hemicellulose, and the dry matter content of the primary feedstock FS is between 30% and 40% by weight. Such by-products contain only a small amount of cellulose. Thus, in one embodiment, the biomass comprises at least one of lignin and hemicellulose, and contains at most 10% by weight of cellulose fiber, on a dry basis. In one embodiment, the biomass comprises at least one of lignin and hemicellulose and contains at most 10% by weight cellulose fiber on an anhydrous basis, and the dry matter content of the primary feedstock FS is between 30% and 40% by weight. As described above, since the salts are removed from the conversion reactor 100, it is now possible to use such highly salty materials as a feedstock for bio-oil production and / or to use the salts as catalysts for the conversion. Furthermore, in such an embodiment, at least one of the salt-rich fractions may be fed to a chemical recovery boiler 500 to recover cooking chemicals from the salt-rich fraction, as shown above.

[0034] More precisely, in the above, the term "black liquor" refers to the by-product from the Kraft process when pulpwood is decomposed into paper pulp by removing lignin, hemicellulose and other extractives from wood to liberate cellulose fibers. Typically, black liquor contains 30% to 40% by weight of carbon when measured on an anhydrous basis. Therefore, black liquor is suitable as a feedstock material for liquid bio-oil.

[0035] Typically, however, black liquor contains 32% to 38% by weight of oxygen (on an anhydrous basis). Thus, the oil-rich fraction obtainable by catalytic conversion may contain significant amounts of oxygen. However, as mentioned above, oxygen may impart bio-oil quality. Thus, when black liquor is used as the feedstock FS or as part of the feedstock FS, preferably the oil-rich fraction OF is further reacted in a second process zone Z2, as discussed above and shown in FIG. 8. The catalytic reactor 200 with the second process zone Z2 is drawn with a dotted line to indicate that it is used only if necessary from the point of view of the bio-oil quality.

[0036] Typically, biomass generally contains a moderate amount of oxygen. In general, this may end up in the bio-oil OIL. The amount of oxygen in the bio-oil may depend on the salts of the primary feedstock FS. However, the salts have adequate functionality at least when the oxygen content of the feedstock biomass is significantly high. Thus, in one embodiment, the oxygen content of the biomass is between 30% and 43% by weight. Here, oxygen content refers to the oxygen content of the dry biomass. Correspondingly, in one embodiment, the oxygen content of the dry primary feedstock is between 30% and 43% by weight. Dry primary feedstock means a material that can be obtained from the primary feedstock FS by drying.

[0037] Due to oxygen, the oil-rich OF may contain oxygen. For example, in one embodiment, the oil-rich fraction OF contains less than 20% by weight of oxygen, such as at most 15% by weight of oxygen, such as between 5% and 15% by weight of oxygen. The oxygen content of the oil-rich fraction OF may be less than 10% by weight, such as between 5% and 10% by weight. If the oil-rich fraction OF is not further reacted in the second process zone Z2, the bio-oil may contain substantially the same amount of oxygen. If the oil-rich fraction OF is further reacted in the second process zone Z2, the bio-oil may contain significantly less oxygen. In one embodiment, the oxygen content of the bio-oil is at most 10% by weight, preferably at most 5% by weight.

[0038] The term "salt" (of the primary feedstock) refers to a chemical compound consisting of a collection of cations and anions. Because salts consist of cations (positively charged ions) and anions (negatively charged ions), the product is electrically neutral (without a net charge). As described above, the primary feedstock FS includes a first salt and a second salt. In the primary feedstock, at least a portion of the salt may be dissolved in the water of the primary feedstock. Specifically, in one embodiment, at least one of the first salt and the second salt is a salt capable of catalyzing the reaction of biomass with water to produce bio-oil. More preferably, the first salt is a salt capable of catalyzing the reaction of biomass with water to produce bio-oil.

[0039] Metals with negative electronegativity appear to catalyze the conversion reaction. Moreover, the greater the electronegativity of a metal, the better it appears to function as a catalyst. Thus, in a preferred embodiment, at least one of the salts of the primary feedstock FS is a salt of a metal having a standard electrode potential at a temperature of 298 K at most -0.5 V. As mentioned above, this salt is recovered from the process as part of the first salt-rich fraction SF1 or as part of the second salt-rich fraction SF2. Thus, in the present invention, at least one of the first salt and the second salt is a salt of a metal having a standard electrode potential at a temperature of 298 K at most -0.5 V. Examples of such metals are lithium (Li), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), aluminum (Al), zinc (Zn), and chromium (Cr). In a more preferred embodiment, at least one of the first salt and the second salt is a salt of a metal having a standard electrode potential at a temperature of 298 K at most −1.5 V. Examples of such metals are lithium (Li), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), and aluminum (Al).

[0040] Even more preferably, the first salt is a salt of a metal that has a standard electrode potential at a temperature of 298 K of at most -1.5 V. This facilitates recycling of (at least a portion of) the first salt back to the first process zone Z1 for reuse as a catalyst. Recycling the first salt is preferred over recycling the second salt, because the second salt may block the conversion reactor 100.

[0041] However, the first salt does not need to be returned to the conversion reactor 100. As shown below, the first salt may be a type 1 salt that produces a brine. Typical first salts include chloride of sodium (NaCl) or chloride of potassium (KCl), and the first salt is included in the first salt-rich fraction SF1. It is feasible to control the salt content of the first salt-rich fraction SF1 so that recycle is not required. For example, if the first salt-rich fraction SF1 is withdrawn only when its salt content is high enough, this means that the salt content in the conversion reactor 100 is also high, thereby not requiring recycle. Recycle is not required because the catalyst (i.e., salt) content is sufficient in the first process zone Z1. However, if the first salt-rich fraction SF1 has a low salt content, it may be returned to the first process zone Z1 to increase the amount of catalyst therein.

[0042] In one embodiment, the primary feedstock FS comprises at least one of the following salts: - salts of sodium, such as NaOH, Na2CO3, NaHCO3, Na2S, Na2SO3, Na2S2O3 or Na2SO4, - a salt of potassium, such as KOH or K2CO3, and - hydroxides, carbonates, bicarbonates, sulfides, sulfites, thiosulfates and sulfates of metals which have standard electrode potentials at a temperature of 298 K of at most -0.5 V.

[0043] In a preferred embodiment, the primary feedstock FS comprises at least one of NaOH, Na2CO3, NaHCO3, KOH, K2CO3, KHCO3.

[0044] In one embodiment, the total salt content of the primary feedstock FS is at least 0.2% by weight, preferably between 0.2% and 40% by weight. Preferably, the total salt content of the dry primary feedstock FS is at least 0.5% by weight (anhydrous basis), preferably between 0.5% and 60% by weight, as measured on anhydrous basis (i.e. from the dry matter of the primary feedstock FS). More preferably, the primary feedstock FS comprises at least 0.1% by weight of ions of sodium or potassium. Even more preferably, the dry matter of the primary feedstock (FS) comprises at least 0.5% by weight (anhydrous basis) of sodium and / or potassium.

[0045] The feedstock containing biomass may be a feedstock that can itself be converted according to the above principles. The feedstock, for example black liquor, may thus serve as a primary feedstock. In this way, no salt (or water) needs to be added to the primary feedstock FS. In the case of a liquid, for example black liquor, some water may be removed by evaporation to obtain condensed black liquor. The condensed black liquor may serve as a primary feedstock FS.

[0046] However, some feedstocks do not necessarily contain sufficient salt and / or water. Thus, at least one of these may be added. Additionally, as an alternative to salt, some make-up catalyst may be added to the feed stream. Referring to FIG. 2, an embodiment includes receiving a secondary feedstock FS2. The secondary feedstock FS2 may, for example, be substantially salt-free. In such a case, since the conversion reaction in the first reaction zone Z1 is inefficient for the second feedstock FS2 itself, the embodiment includes adding at least one of salt FS3 and make-up catalyst FS4 to the secondary feedstock FS2 to produce a primary feedstock FS. The primary feedstock FS can then be processed as detailed above. Alternatively or additionally, water can be added to the secondary feedstock FS2, if necessary. Suitable dry matter contents for the primary feedstock FS are detailed above. Salt FS3 may be recycled from the conversion reactor 100 and may include at least a portion of one of the first salt-rich fraction SF1 and the second salt-rich fraction SF2.

[0047] Due to the withdrawal of the salt-rich fractions SF1 and SF2, the salt content of the bio-oil OIL is less than the salt content of the primary feedstock FS. Moreover, preferably, the salt comprises at least one of sodium and potassium. Thus, in one embodiment, the primary feedstock FS comprises at least one of sodium and potassium, the primary feedstock FS having a first content of sodium and potassium, where the first content refers to the total content of sodium and potassium as measured in weight percent. Furthermore, the liquid bio-oil OIL has a second content of sodium and potassium, where the second content refers to the total content of sodium and potassium as measured in weight percent. Due to the removal of the salt-rich fraction SF, the second content is less than the first content. The second content may be, for example, at least one percentage unit less than the first content, where the first and second contents are measured in weight percent.

[0048] By cooling at least one of the oil-rich fraction OF and its reaction product RP, at least a portion of at least one of the oil-rich fraction OF and its reaction product RP, respectively, is condensed. Moreover, the term liquid bio oil means oil that is in a liquid state at atmospheric pressure and at a temperature between 5° C. and 95° C. Thus, one embodiment comprises cooling the oil-rich fraction OF or its reaction product RP to a temperature between 5° C. and 90° C. to produce liquid (i.e. condensed) bio oil OIL.

[0049] Not all compounds of the oil-rich fraction or its reaction product RP need to be condensed at such temperatures. Such compounds include carbon monoxide or carbon dioxide. Compounds that do not condense at the aforementioned temperatures may be removed as non-condensable gases. Furthermore, water (i.e., the water-rich fraction) can be separated from the oil-rich fraction OF or the condensate of the reaction product RP to obtain bio-oil OIL. Thus, an embodiment comprises separating at least one of a non-condensable gas (NCG) and a water-rich fraction (WF) from the oil-rich fraction OF or the condensate of its reaction product RP to produce a liquid bio-oil OIL (Figures 1e and 3a). Even if such separation is only shown in the context of Figures 1e and 3a, such separation may be applied in the context of any embodiment that includes cooling, in particular in the context of any figure except Figures 1a, 1b and 3e. Here, the term non-condensable gas refers to a substance whose boiling point at atmospheric pressure is at most 0°C. Thus, one embodiment comprises at least one - a gas whose boiling point at atmospheric pressure is at most 0°C, and - Water-rich fraction (WF) from the oil-rich fraction (OF) or its reaction product (RP) condensate to produce liquid bio-oil (OIL).

[0050] An embodiment includes reducing the pressure of one of (i) the oil-rich fraction OF, (ii) the reaction product RP of the oil-rich fraction OF, and (iii) the bio-oil OIL to between 0.5 bar(a) and 2.0 bar(a), where bar(a) refers to absolute pressure. An embodiment includes reducing the pressure of one of the oil-rich fraction OF, the reaction product RP of the oil-rich fraction OF, and the bio-oil OIL to atmospheric pressure. An embodiment includes discharging the liquid bio-oil at a temperature between 5° C. and 95° C. at a pressure between 0.5 bar(a) and 2.0 bar(a). An embodiment includes discharging the liquid bio-oil at a temperature between 50° C. and 95° C. at atmospheric pressure.

[0051] It has been found that the oxygen content of bio-oil can be affected by at least the following: (a) the type of salt used to catalyze the conversion process; (b) the reaction temperature of the conversion process; (c) the residence time of the reaction, i.e., the reaction time, t, and (d) Use of a solid catalyst for converting the oil-rich fraction OF into a reaction product RP of the oil-rich fraction OF.

[0052] Regarding (a), the effect of salt was discussed above.

[0053] Regarding (b), preferably, the reaction temperature T in the first reaction zone Z1 is between 375° C. and 450° C. and the pressure p is between 220 bar and 350 bar.

[0054] Regarding (c), the reaction time has been discussed above, but preferably the reaction time is from 5 minutes to 30 minutes.

[0055] With regard to (d), referring to Figures 3a-3d, the oil-rich fraction OF can be catalytically treated (i.e., converted) to form a reaction product RP. Thereafter, if necessary, the reaction product RP can be cooled to produce a bio-oil OIL. For these reasons, referring to Figures 3a-3d, an embodiment includes feeding the oil-rich fraction OF to a second reaction zone Z2 and allowing the oil-rich fraction OF to react in the presence of a solid catalyst CAT in the second reaction zone Z2 to produce a reaction product RP of the oil-rich fraction OF. The solid catalyst CAT is also a heterogeneous catalyst, meaning that the phase of the catalyst (solid) is different from the phase of the primary feedstock FS (liquid, gas, or supercritical).

[0056] In these embodiments, the solid catalyst CAT has at least a deoxygenation functionality. The catalyst CAT is a solid catalyst in the sense that it is insoluble in the oil-rich fraction OF. The solid catalyst CAT may be a supported catalyst. The solid catalyst CAT may form a bed of catalytic material in which the oil-rich fraction OF is carried.

[0057] A corresponding system comprises a solid catalyst material CAT in a second process zone Z2, which may be located in the conversion reactor 100 or the catalytic reactor 200. The solid catalyst CAT is configured to convert the oil-rich fraction OF into the reaction product RP. In one embodiment, the solid catalyst CAT is configured to convert the oil-rich fraction OF into the reaction product RP by deoxygenating at least some compounds of the oil-rich fraction.

[0058] The purpose of the solid catalyst CAT is to deoxygenate the oxygenated hydrocarbons of the oil-rich fraction OF. In the deoxygenation, the deoxygenation reaction deoxygenates at least a portion of the oxygenated hydrocarbons to hydrocarbons or at least less oxygenated hydrocarbons. In the reaction, at least a portion of the oxygen (O) bound to the oxygenated hydrocarbons is removed from the oxygenated hydrocarbons, thereby deoxygenating these hydrocarbons. Depending on the solid catalyst CAT, hydrogen may be added, but not necessarily to the second reaction zone Z2. The removed oxygen forms other oxygen-containing compounds, such as water H2O, carbon monoxide CO, and / or carbon dioxide CO2, together with other components of the oil-rich fraction. Some light and oxygenated hydrocarbons may also be formed as a result of the reaction. These compounds may be removed from the reaction product RP or bio-oil OIL, for example during condensation.

[0059] As shown in Figures 3a-d, these embodiments include condensing the reaction product RP of the oil-rich fraction OF to produce a liquid bio-oil OIL. As shown in Figure 3e, the reaction product RP of the oil-rich fraction OF does not need to be cooled.

[0060] 3a shows an embodiment in which such a solid catalyst CAT is used, where no addition of hydrogen is required. Furthermore, a catalytic reactor 200, separate from the conversion reactor 100, is used for catalytically processing the oil-rich fraction OF. Correspondingly, the oil-rich fraction is conveyed from the conversion reactor 100 to the catalytic reactor 200.

[0061] 3b shows an embodiment in which such a solid catalyst CAT is used, where addition of hydrogen is required. Hydrogen is therefore added to the catalytic reactor 200. Furthermore, a catalytic reactor 200 separated from the conversion reactor 100 is used for catalytically processing the oil-rich fraction OF. Correspondingly, the oil-rich fraction is conveyed from the conversion reactor 100 to the catalytic reactor 200.

[0062] In the embodiment of Figures 3a and 3b, the temperature in the catalytic reactor 200 may be different from the temperature T in the conversion reactor 100. Depending on the catalyst CAT, it may be beneficial for the temperature in the second reaction zone Z2 of the catalytic reactor 200 to be higher than the temperature in the first reaction zone Z1 of the conversion reactor 100. In the embodiment of Figures 3a and 3b, the pressure in the catalytic reactor 200 may be different from the pressure p in the conversion reactor 100. Having a separate catalytic reactor 200 allows a reasonable degree of freedom in the selection of the solid catalyst CAT.

[0063] 3c shows an embodiment in which such a solid catalyst CAT is used, where no addition of hydrogen is required. Furthermore, the second process zone Z2 and the solid catalyst CAT are arranged in the conversion reactor 100. Thus, even if the oil-rich fraction OF is transferred to the second reaction zone Z2, the oil-rich fraction is transferred only in one conversion reactor 100. Thus, the reaction product RP can be withdrawn from the conversion reactor 100.

[0064] Figure 3d shows an embodiment in which such a solid catalyst CAT is used, for which addition of hydrogen is required, otherwise this embodiment corresponds to the embodiment of figure 3c.

[0065] In the embodiment of Figures 3c and 3d, the temperature in the second process zone Z2 may be substantially the same as the temperature T in the first reaction zone Z1. In the embodiment of Figures 3c and 3d, the pressure in the second process zone Z2 may be substantially the same as the pressure p in the first reaction zone Z1. This may present some limitations to the solid catalyst CAT, but allows for the use of a simpler system than the embodiment of Figures 3a and 3b.

[0066] 3b and 3d, some embodiments include also supplying hydrogen H2 to the second reaction zone Z2, and reacting the oil-rich fraction OF and hydrogen H2 in the second reaction zone Z2. The corresponding system includes a second inlet 102 for allowing hydrogen to enter the second process zone Z2. The second inlet 102 may be located in the conversion reactor 100 or the catalytic reactor 200.

[0067] The temperature in the second process zone Z2 preferably differs from the temperature in the first process zone Z1 by at most 50° C. More preferably, the temperature in the second process zone Z2 differs from the temperature in the first process zone Z1 by at most 20° C. However, depending on the catalyst, the temperature difference between the reactors 100 and 200 may be larger.

[0068] The residence time in the second process zone Z2 may be, for example, at least 15 minutes, at least 30 minutes, or at least 60 minutes. The residence time is related to the pressure in the second process zone Z2. Generally, the higher the pressure, the shorter the residence time. The pressure in the second process zone may be, for example, at least 50 bar, at least 100 bar, or at least 120 bar.

[0069] With regard to the term oxygen content, in this specification, the oxygen content of a substance (e.g., oil-rich fraction OF, bio-oil OIL, primary feedstock FS, or biomass thereof) refers to the total weight of oxygen atoms in the dry substance relative to the total weight of the dry substance. The oxygen content is measured in weight % (anhydrous basis). As mentioned above, the oxygen content of the (dry) primary feedstock may be in the range of 30% to 45% by weight. In one embodiment, the primary feedstock FS is converted such that the oxygen content of the oil-rich fraction is at most 20% by weight, preferably at most 15% by weight. Correspondingly, in one embodiment, the oxygen content of the bio-oil is at most 20% by weight, preferably at most 15% by weight. Such low oxygen contents appear to be achievable without the use of a solid catalyst CAT. In addition to oxygen, the oil-rich fraction may contain sulfur and / or nitrogen.

[0070] However, when a solid catalyst CAT is used, the oxygen content of the reaction product RP and / or the bio-oil OIL may be lower due to deoxygenation reactions. Thus, in at least one embodiment where a solid catalyst CAT is used, the oxygen content of the reaction product RP is at most 10%, preferably at most 5%. Furthermore, in at least one embodiment where a solid catalyst CAT is used, the oxygen content of the bio-oil OIL is at most 10%, preferably at most 5%. However, depending on the feedstock, salts, and process conditions in the first process zone Z1, it may be possible to produce a bio-oil OIL in which the oxygen content of the bio-oil OIL is at most 10%, preferably at most 5%, even if a solid catalyst CAT is not used.

[0071] Furthermore, when a solid catalyst CAT is used, the nitrogen content may also be reduced by catalytic treatment in the presence of the solid catalyst CAT. In one embodiment, the oil-rich fraction OF contains at least 750 ppm nitrogen. In one embodiment, the oil-rich fraction OF contains 1000 ppm to 3000 ppm nitrogen. Due to the catalytic treatment with the solid catalyst CAT, in one embodiment, the bio-oil contains at least 15% less nitrogen.

[0072] 4a-4c, bio-oil may be refined. Reference numeral 300 in the figure indicates the refinement of bio-oil OIL. Any of the following bio-oils may be refined: - Bio-oil produced without the use of solid catalyst CAT (see Figure 4a); - bio-oil produced by converting the oil-rich fraction OF into the reaction product RP over a solid catalyst CAT, such as one that works without the addition of hydrogen (see Figure 4b), and - Bio-oil produced by converting the oil-rich fraction OF into the reaction product RP over a solid catalyst CAT, such as one functioning with hydrogen (see Figure 4c).

[0073] Referring to Figures 3c and 3d, a catalytic reactor 200 can be integrated with the conversion reactor 100, and such bio-oil can also be refined (not shown).

[0074] With regard to refining 300, a deoxygenation or deoxygenation process can be used to reduce the oxygen content of the bio-oil. Additionally or alternatively, fractionation, such as distillation, can be performed. Thus, one embodiment includes refining (300) the bio-oil OIL, for example, by hydrodeoxygenation and / or by hydrodeoxygenation, to produce a refined bio-oil. One embodiment includes fractionating the bio-oil OIL.

[0075] Heating the primary feedstock FS requires a lot of energy because the process temperatures are high, therefore heat is preferably recovered from and utilized in the process.

[0076] Thus, in one embodiment, the cooler 110 comprises a heat exchanger 115 configured to cool at least one of the oil-rich fraction OF and the reaction product RP. With reference to Figures 5a-5f, preferably, the heat so recovered is used to heat the primary feedstock FS. Thus, an embodiment of the method comprises transferring heat from at least one of the oil-rich fraction OF and the reaction product RP of the oil-rich fraction OF to the primary feedstock FS. Correspondingly, an embodiment of the system comprises a heat exchanger 115 configured to transfer heat from at least one of the oil-rich fraction OF and the reaction product RP of the oil-rich fraction OF to the primary feedstock FS (or to a part thereof, see Figure 2 with heater 130).

[0077] The heat exchanger 115 can be seen as or configured by the heater 130 described above. Thus, the heater 130 of the system may include the heat exchanger 115. Figures 5a-5c show heat transfer only from the oil-rich fraction OF and the heat exchanger 115 configured to transfer heat from the oil-rich fraction OF to the primary feedstock FS.

[0078] 5d-5f show the heat transfer from the reaction product RP of the oil-rich fraction OF and a heat exchanger 115 configured to transfer heat from the reaction product RP of the oil-rich fraction OF to the primary feedstock FS.

[0079] Even if such a heat exchanger 115 is used as the heater 130 for the primary feedstock FS, the system may include a second heater 130' configured to further heat the primary feedstock FS. Such a second heater 130' is shown in Figures 5b, 5c, 5e and 5f. The cooler 110 may include multiple heat exchangers in series to improve heat recovery to the primary feedstock FS.

[0080] As described above, in the method and / or system, Type 2 salt is solidified and removed from conversion reactor 100, so that Type 2 salt does not clog the interior walls of conversion reactor 100. Figures 6a, 6b, 6c and 7 show specific means for solidifying Type 2 salt.

[0081] With reference to Figures 6a and 6b, the conversion reactor 100 may include a crystallizer 310. In general, an internal circulation is provided to the crystallizer. The internal circulation may be provided by a rotor 312, as shown in Figures 6a and 6b. Thus, in these figures, the crystallizer 310 includes a rotor 312 configured to form an internal circulation in the crystallizer 310. In general, as an alternative to the rotor 312, a pump may be configured to form an internal circulation in the crystallizer 310. Thus, in general, the crystallizer includes a means for forming an internal circulation in the crystallizer 310. Due to the internal circulation, salts that tend to solidify crystallize on the internal crystallization nuclei of the feedstock FS. Thus, type 2 salts do not accumulate on the surfaces of the conversion reactor 100. The fractions SF1 and SF2 rich in the first and second salts may be withdrawn from the crystallizer 310 forming part of the conversion reactor 100. In an embodiment in which the crystallizer forms only a part of the conversion reactor 100, the first salt-rich fraction SF1 may be withdrawn from the conversion reactor 100 downstream from the crystallizer 310 (see FIG. 6c). However, the first salt-rich fraction may also be withdrawn from the crystallizer 310 in such a case, as in FIGS. 6a and 6b. However, preferably, in such an embodiment, at least the second salt-rich fraction SF2 is withdrawn from the crystallizer 310 (see FIG. 6c).

[0082] With particular reference to FIG. 6b, when the crystallizer 310 is used, a classifier 320 may also be used. Generally, by using the crystallizer 310, precipitates of various sizes are formed as a result of crystallization. Furthermore, due to internal circulation, the precipitates grow. The classifier 320 may be used to form a classified salt fraction CSF. The classifier 320 is configured to receive the second salt-rich fraction SF2. Furthermore, the classifier 320 is configured to separate the classified salt concentration CSF from the second salt-rich fraction SF2, and the average precipitate size of the classified salt fraction CSF is larger than the average precipitate size of the second salt-rich fraction SF2. Generally, most of the precipitates having a particle size above the threshold are allowed to pass the classifier 320 to the classified salt fraction CSF, and most of the precipitates having a particle size below the threshold are returned to the crystallizer 310. Thus, the remainder of the second salt-rich fraction SF2 is returned to the crystallizer to allow the precipitate to grow. Typically, the classifier operates with another fluid, and the first salt-rich fraction SF1 can be used as such an operating fluid. Thus, in one embodiment, at least a portion of the first salt-rich fraction SF1 is conveyed to the classifier 320. The first salt-rich fraction SF1 is conveyed to the classifier 320 from the conversion reactor 100 that includes a crystallizer, and optionally, the first salt-rich fraction SF1 is conveyed to the classifier 320 from the crystallizer 310. In either case, the heater 130 can be used to heat the first salt-rich fraction SF1.

[0083] In connection with the crystallizer 310, both the first and second salt-rich fractions SF1 and SF2 can be collected in such a portion of the conversion reactor 100 that includes a filter (not shown). The filter can be, for example, in a lower portion of the reactor. The second salt-rich fraction SF2 can be separated from the first salt-rich fraction SF1 by using a filter. Thereafter, the different fractions SF1, SF2 can be removed from the conversion reactor 100, as described above.

[0084] In particular, when the feedstock FS comprises black liquor, at least a portion of the second salt-rich fraction SF2 may be conveyed to a recovery boiler 500 for recovery of cooking chemicals.

[0085] Referring to FIG. 7, another possibility to solidify type 2 salt is to use solid particles 410 as precipitation seeds. Such solid particles 410 may be used in the crystallizer 310 of FIG. 6a-6c or even if the conversion reactor 100 does not include a crystallizer 310. In general, crystallization tends to occur on the precipitation seeds. Thus, by providing solid particles 410 in the conversion reactor 100 (and optionally in the crystallizer 310), type 2 salt may be solidified on the solid particles 410. If the density of the crystallized salt is higher than the density of the solid particles 410 without the crystallized salt, the crystallization of the salt will increase the density of the particles 410, and the particles 410 will tend to fall to the bottom of the conversion reactor 100 (or the crystallizer 310) due to gravity. Furthermore, since the solid particles should serve as precipitation seeds, the solid particles 410 should not float in the reactor 100 even if they are not covered by salt. Thus, the density of the solid particles 410 should be approximately the same as the density of the feedstock FS. Thus, in one embodiment, the feedstock in the first reaction zone Z1 has a density of approximately 1000 MPa (e.g., kg / m 3 The solid particles 410 have a first density ρ1 (as measured by |ρ2-ρ1) and the solid particles 410 have a second density ρ2. Further, in one embodiment, the absolute value of the difference between the densities relative to the first density (i.e., |(ρ2-ρ1) / ρ1|) is at most 25%. Thus, in one embodiment, the density ρ2 of the solid particles 410 deviates from the density ρ1 of the material in the first reaction zone Z1 by at most 25%. More preferably, the second density ρ2 is equal to or slightly (e.g., at most 10%) less than the first density ρ1. Thus, the relative difference (ρ1-ρ2) / ρ1 may be 0-10%. In a typical conversion process, the density of the feedstock in the first reaction zone Z1 is about 400 kg / m 3Furthermore, typically all solidified salts have a higher density than this. Thus, in one embodiment, the density of the solid particles when not covered with solidified salt is greater than 200 kg / m 3 ~800kg / m 3 In particular, if a crystallizer 310 is used, the internal circulation may provide sufficient mixing of the feedstock and the solid particles even if the difference between the densities is large.

[0086] Referring to Figure 7, when the salt solidifies on the solid particles 410, the solid particles gain weight, thereby increasing their density. Thus, the coated solid particles may fall downward and be withdrawn from the lower portion of the conversion reactor 100 (e.g., from its crystallizer). Thus, the second outlet 104 is located at the lower portion (e.g., bottom) of the conversion reactor. This is shown diagrammatically in Figure 7. Furthermore, the second salt-rich fraction SF2 comprises the solidified second salt in the form of shells of the solid particles 410.

[0087] The solid particles 410 covered with the coagulated salt may be transported to a vessel 420. It may be economically viable to reuse the solid particles 410. Thus, in one embodiment, some of the solid particles 410 covered with the coagulated salt are washed in the vessel 420. Water may be used as a washing liquid. Water may be added to the vessel 420. However, the water of the second salt-rich fraction SF2 may be sufficient to dissolve the salt if the temperature is reduced to subcritical conditions. As mentioned above, the coagulation of the salt is mainly due to the supercritical conditions in the first process zone Z1. Thus, by adjusting the conditions to subcritical, the salt may dissolve in the water of the second salt-rich fraction SF2. As the salt dissolves in the washing solution or the water of the second salt-rich fraction SF2, the solid particles 410 become clean of the salt, thereby decreasing their density. The washed particles can then be recycled into the conversion reactor 100 as indicated in FIG. 7 by arrow 422 "Washed Particles." Thus, the system includes a line 422 configured to convey the washed solid particles 410 from the vessel 420 to the conversion reactor 100. The solution withdrawn from the vessel 420 includes the second salt in dissolved form. When at least the feedstock FS includes black liquor, the solution withdrawn from the vessel 420 may be conveyed to the recovery boiler 500 or an evaporator disposed upstream of the recovery boiler 500. Typically, the black liquor is condensed in such an evaporator.

[0088] 7, both the first and second salt-rich fractions can be delivered to vessel 420, which can then be viewed as part of reactor 100. Vessel 420 can include a filter to separate particles 410 having solidified second salt (i.e., second salt-rich fraction SF2) from the brine (i.e., first salt-rich fraction SF1). These fractions can be removed from vessel 420 through different outlets (not shown).

[0089] Preferably, hollow or porous metal particles are used as solid particles 410. Metals are typically able to withstand the high temperatures and pressures of the first process zone Z1. However, some metals have melting points that are too low in view of supercritical conditions. Thus, the metal particles may be made of metals or metal alloys that have a melting point of at least 400° C. Furthermore, the density of many metals is too high considering what has been said about the density of the solid particles 410. However, hollow particles have a smaller density. The metal particles - the size and wall thickness of hollow metal particles, or - porosity By appropriately selecting , it is possible to produce solid particles 410 that can withstand the process environment of the first process zone Z1 and have the aforementioned density. [Prior art documents] [Non-patent literature]

[0090] [Non-Patent Document 1] Thomas Voisin, Arnaud Erriguible, David Ballenghien, David Mateos, Andre Kunegel, et al.. Solubility of inorganic salts in sub- and supercritical hydrothermal environment: Application to SCWO processes. Journal of Supercritical Fluids, Elsevier, 2017, 120, Part 1, pp.18-31. 10.1016 / j.supflu.2016.09.020.hal-01417006.

Claims

1. 1. A method for producing an oil-rich fraction from biomass, comprising: providing a primary feedstock comprising water, a first salt, a second salt, and biomass to a first reaction zone of a conversion reactor; allowing the primary feedstock to react in the first reaction zone at a temperature of at least 350° C. and a pressure of at least 160 bar to form a converted primary feedstock; separating a first salt-rich fraction, a second salt-rich fraction, and an oil-rich fraction from the converted primary feedstock at a temperature of at least 350° C. and a pressure of at least 160 bar; withdrawing the oil-rich fraction from the first reaction zone; withdrawing the first salt-rich fraction and the second salt-rich fraction from the conversion reactor; the first salt-enriched fraction comprises at least a portion of the first salt that is dissolved in the water; the second salt-enriched fraction comprises at least a portion of the second salt in solid form; at least one of the first salt and the second salt is capable of catalyzing the reaction of the biomass of the primary feedstock with the water of the primary feedstock to produce the oil-rich fraction; said first salt being a Type 1 salt; the second salt is a Type 2 salt; the solubility of the Type 2 salt decreases as a function of increasing temperature at or near supercritical conditions more rapidly than the solubility of the Type 1 salt; method.

2. 10. The method of claim 1, wherein the method includes recycling the salt or salts for use as a catalyst and / or to recover materials from the salt or salts.

3. The method includes feeding at least a portion of the first salt-rich fraction and / or at least a portion of the second salt-rich fraction into the first reaction zone of the conversion reactor; Preferably, at least a portion of the first salt-rich fraction is fed into the first reaction zone of the conversion reactor. The method according to claim 1 or 2.

4. the primary feedstock comprises black liquor; The method includes feeding at least a portion of the first salt-rich fraction and / or at least a portion of the second salt-rich fraction into a chemical recovery boiler configured to combust the black liquor; Preferably, at least a portion of the second salt-rich fraction is fed into the chemical recovery boiler. The method according to any one of claims 1 to 3.

5. 1. A method for producing an oil-rich fraction from biomass, comprising: providing a primary feedstock comprising water, a first salt, a second salt, and biomass to a first reaction zone of a conversion reactor; allowing the primary feedstock to react in the first reaction zone at a temperature of at least 350° C. and a pressure of at least 160 bar to form a converted primary feedstock; separating a first salt-rich fraction, a second salt-rich fraction, and an oil-rich fraction from the converted primary feedstock at a pressure of at least 160 bar and a temperature of at least 350° C.; withdrawing the oil-rich fraction from the first reaction zone; withdrawing the first salt-rich fraction and the second salt-rich fraction from the conversion reactor; the first salt-enriched fraction comprises at least a portion of the first salt that is dissolved in the water; the second salt-enriched fraction comprises at least a portion of the second salt in solid form; at least one of the first salt and the second salt is capable of catalyzing the reaction of the biomass of the primary feedstock with the water of the primary feedstock to produce the oil-rich fraction; said first salt being a Type 1 salt; the second salt is a Type 2 salt; the solubility of said Type 2 salt decreases as a function of increasing temperature at or near supercritical conditions more rapidly than the solubility of said Type 1 salt; [A] the method includes feeding at least a portion of the first salt-rich fraction and / or at least a portion of the second salt-rich fraction into the first reaction zone of the conversion reactor; and / or [B] the primary feedstock comprises black liquor, the method comprising feeding at least a portion of the first salt-rich fraction and / or at least a portion of the second salt-rich fraction into a chemical recovery boiler configured to combust the black liquor; method.

6. at least one of the first salt and the second salt is a salt of a metal having a standard electrode potential at a temperature of 298 K of at most −0.5 V, preferably at most −1.5 V; Preferably, the first salt is a salt of a metal having a standard electrode potential at a temperature of 298 K of at most -1.5 V; More preferably, the first salt is a potassium (K) or sodium (Na) salt. The method according to any one of claims 1 to 5.

7. the total content of said first and second salts in said primary feedstock is at least 1 wt. %, preferably between 5 wt. % and 40 wt. %; Preferably, the total content of said first and second salts in the dry matter of said primary feedstock is at least 1 wt.-%, preferably between 5 wt.-% and 40 wt.-%; More preferably, the primary feedstock comprises at least 1 wt. % ions of sodium and / or potassium; Even more preferably, the dry matter of the primary feedstock contains at least 1% by weight of sodium and / or potassium ions. The method according to any one of claims 1 to 6.

8. The method includes cooling at least one of the oil-rich fraction and the reaction product of the oil-rich fraction, preferably to a temperature of from 5° C. to 95° C. to produce a liquid bio-oil; Preferably, the method further comprises separating at least one of a non-condensable gas and a water-rich fraction from the oil-rich fraction or a condensate of its reaction products to produce the liquid bio-oil. The method according to any one of claims 1 to 7.

9. The method comprises: recovering heat from the oil-rich fraction or a reaction product thereof to produce the liquid bio-oil; and heating at least a portion of the primary feedstock with the recovered heat. The method according to claim 8.

10. 10. The method according to claim 8 or 9, wherein the oxygen content of the liquid bio-oil is at most 20%, preferably at most 15%.

11. The method according to any one of claims 1 to 10, wherein the oxygen content of the oil-rich fraction is at most 20% by weight, preferably at most 15% by weight.

12. 12. The process of any one of claims 1 to 11, comprising allowing the primary feedstock to react in the first reaction zone at a temperature of from 350°C to 450°C at a pressure of from 220 bar to 350 bar for at least 5 minutes.

13. 13. The method of any one of claims 1 to 12, wherein the method comprises crystallizing at least a portion of the second salt in a crystallizer to form a crystallized second salt.

14. The method includes crystallizing at least a portion of the second salt onto solid particles; Preferably, the process comprises crystallizing at least a portion of said second salt on solid particles having a density that deviates from a density of said primary feedstock by at most 25% in said first reaction zone; More preferably, the method comprises crystallizing at least a portion of said second salt on hollow metal particles. The method according to any one of claims 1 to 13.

15. transferring said oil-rich fraction to a second reaction zone; allowing the oil-rich fraction to react in the presence of a solid catalyst in the second reaction zone to produce a reaction product; Optionally, the method further comprises: also supplying hydrogen to said second reaction zone; allowing the oil-rich fraction and the hydrogen to react in the second reaction zone; Preferably, the solid catalyst has at least a deoxygenation functionality. The method according to any one of claims 1 to 14.

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