PROCESS FOR PRODUCING CRUDE BIO-OIL FROM BIOMASS WITH A HIGH MOISTURE CONTENT AND CATALYST FOR HYDROTHERMAL LIQUEFACTION OF STREAMS OF BIOMASS WITH A HIGH MOISTURE CONTENT

Abstract

The present invention addresses to a hydrothermal liquefaction process capable of generating a liquid stream, rich in renewable molecules, with lower oxygen content, lower percentage of water and lower acidity compared to other products of thermochemical processes of biomass conversion. In order to effectively carry out this process, a catalyst was developed, obtained from the calcination of castor bean hull, to be used in the field of biofuels in order to provide an environmentally friendly alternative for the production of fuels.

Claims

1.—A PROCESS TO PRODUCE CRUDE BIO-OIL FROM BIOMASS WITH HIGH MOISTURE CONTENT, characterized in that it comprises the following steps: a) mixing water or recycle aqueous fraction with residual lignocellulosic biomass to form a mixture with solid content in the range of 5% to 20% by weight; b) adding a catalyst, generated from a residue of a biomass, to the mixture obtained in (a) so that the catalyst concentration in relation to the dry biomass is from 1% to 10% m/m, preferably 5% m/m; c) hydrothermally liquefying (HTL) a mixture formed by water, biomass and catalyst, by heating the same to a temperature in the range of 250 to 300° C. and a pressure of 900 to 1300 psig (6.205 to 8.963 MPa); d) cooling the reaction products; e) sending the products to a separator where the gaseous, solid, oily and aqueous streams containing the catalyst are separated; and f) reusing said aqueous fraction containing catalyst and soluble oxygen compounds.

2.—THE PROCESS according to claim 1, characterized in that the streams of replacement water, recycled aqueous fraction, replacement catalyst and biomass feed the liquefaction reactor.

3.—THE PROCESS according to claim 1, characterized in that the oily stream obtained in step (e), called bio-oil, is rich in renewable molecules.

4.—THE PROCESS according to claim 1, characterized in that the gaseous stream can be optionally recycled to the reactor to maintain a reducing atmosphere or undergo a membrane separation process to obtain syngas.

5.—THE PROCESS according to claim 1, characterized in that the gaseous stream can generate energy by means of its total oxidation.

6.—THE PROCESS according to claim 1, characterized in that the aqueous stream is recycled in order to reuse the catalyst and reinsert the water-soluble oxygenated compounds into the reaction medium.

7.—THE PROCESS according to claim 1, characterized in that the solid stream can be used, alternatively, as a raw material for the production of adsorbents.

8.—THE PROCESS according to claim 1, characterized in that it additionally comprises a step of recovery and recycling of the catalyst, in steps (e) and (f), respectively.

9.—THE PROCESS according to claim 1, characterized in that the biomass is selected from the group consisting of biomass of any cellulosic material; lignin, obtained from sugarcane bagasse by means of the acid hydrolytic process; any fatty material; any proteinaceous material or a mixture of two or more of the above-described materials.

10.—THE PROCESS according to claim 1, characterized in that the catalyst used is a homogeneous catalyst.

11.—THE PROCESS according to claim 1, characterized in that the catalyst is a compound mostly of potassium.

12.—THE PROCESS according to claim 1, characterized in that the generated aqueous fraction is recycled, which contains the catalyst and some of the oxygenated products, so that the replacement of water for the process is minimized, the catalytic activity is maintained and the bio-oil yield is increased due to the incorporation of oxygenated compounds into the reaction medium.

13.—THE PROCESS according to claim 1, characterized in that the liquefaction rates are greater than 85% and the yields of the oily stream are greater than 40%.

14.—A BIO-OIL, obtained by the process as defined in claims 1 to 13, characterized in that it is an oily stream, rich in renewable molecules, with lower oxygen content, lower percentage of water and lower acidity than the bio-oils obtained from pyrolysis processes.

15.—A CATALYST FOR HYDROTHERMAL LIQUEFACTION OF BIOMASS STREAMS WITH HIGH MOISTURE CONTENT, as defined in claims 10 and 11, characterized in that it is obtained by means of the calcination of residues from the production of castor oil, known as castor bean hull (epicarp+mesocarp).

16.—THE CATALYST according to claim 15, characterized in that the calcination is carried out at 600° C.

17.—THE CATALYST as defined in claims 15 to 16, characterized in that the use of said catalyst increases the yield of bio-oil by at least 30% compared to the non-catalyzed process.

18.—THE CATALYST according to claims 15 to 16, characterized in that it has a high content of alkali metals (>50%).

19.—THE CATALYST according to claims 15 to 18, characterized in that it is reusable.

20.—THE CATALYST according to claims 15 to 19, characterized in that it has high solubility in water, which makes its reuse possible and allows the process to recycle the entire aqueous fraction formed, drastically reducing water consumption and increasing the yield of bio-oil by the reincorporation of the soluble oxygenated products in the aqueous fraction to the reaction medium, in addition to the reinsertion of the catalyst therein.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0035] The present invention will be described in more detail below, with reference to the attached figures which, in a schematic form and not limiting the inventive scope, represent examples of its embodiment. In the drawings, there are:

[0036] FIG. 1 illustrates a schematic form of the process, in which streams (1), (2), and (3) respectively consists of replacement water, replacement catalyst and biomass that feed the liquefaction reactor (4). After conversion, the products are sent to a separator (5), where the gaseous (6), solid (7), aqueous (8) and oily (bio-crude) (9) streams are separated.

[0037] FIG. 2 presents a graph that addresses to the diffraction pattern of inorganics present in the solid phase, which come from bagasse and not from the catalyst. The results of the graph confirm that the recycling of the aqueous stream promotes the return of the catalyst to the reaction medium.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention proposes an alternative process of hydrothermal liquefaction, without mandatory use of a reducing atmosphere, with the use of a catalyst generated from a residue of a biomass, where said catalyst is produced in order to have useful characteristics for the biomass liquefaction process.

[0039] Among these characteristics, there can be highlighted the high content of alkali metals (>50%) and its high solubility in water, which makes its reuse possible and allows the process to recycle the entire formed aqueous fraction, drastically reducing the consumption of water and increasing the yield of bio-oil by the reincorporation of the soluble oxygenated products in the aqueous fraction to the reaction medium, in addition to the reinsertion of the catalyst therein.

[0040] The proposed liquefaction process uses a catalyst, described above, at temperatures of 250 to 300° C. and low residence time, 0 (zero) min in a reactor operating in batch mode (heating ramp time only of 40 to 60 min), with pressures of 900 to 1300 psig (6.205 to 8.963 MPa), using 1% to 10% m/m, preferably 5% m/m, of catalyst in relation to the dry biomass mass and solids content of 5 to 20% m/m in the load (dry biomass+water).

[0041] In this process, the aqueous stream generated retains the catalytic function obtained by using the catalyst presented above, thanks to its high solubility, and also contains oxygenated compounds. This stream is then recycled, dramatically reducing the need for water in the process and maintaining catalytic activity. The process is characterized by liquefaction rates above 85% and bio-oil yields above 40%.

[0042] The solid residue formed in the process (char) can, alternatively, be burned in boilers for energy generation or as raw material for the generation of adsorbent materials.

[0043] Also alternatively, the gaseous stream can be recycled to the reactor in order to generate a reducing atmosphere; it can be fully oxidized for energy recovery or it can undergo membrane separation processes to obtain syngas (H.sub.2+CO).

[0044] The biomass used as raw material can be any lignocellulosic material; lignin, obtained from sugarcane bagasse by means of an acid hydrolytic process; any fatty material; any proteinaceous material; or even a mixture of two or more materials of those described above.

[0045] As can be seen in FIG. 1, the schematic form of the proposed liquefaction process includes streams (1), (2) and (3), which consist of replacement water, replacement catalyst and biomass, which feed the liquefaction reactor (4).

[0046] After the conversion, the products are sent to a separator (5), where the gaseous (6), solid (7), aqueous (8) and oily (bio-crude) (9) streams are separated.

[0047] FIG. 1 also demonstrates that the stream (6) can be optionally recycled to the reactor to maintain a reducing atmosphere. Another option, not shown in FIG. 1, addresses to the fact that the stream (6) can undergo the membrane separation process to obtain syngas for other applications, and in another inventive aspect, the stream (6) can be used for energy generation by means of its total oxidation.

[0048] FIG. 1 further addresses to the stream (8) that is recycled (stream 10) in order to reuse the catalyst and reinsert the water-soluble oxygenated compounds into the reaction network.

[0049] Another point outlined in FIG. 1 is the direction of the stream (9) to conventional oil refining processes or to treatments aimed at improving the quality of bio-crude.

[0050] In addition, the stream (7) can be directed to a boiler in order to generate energy for the process or even be a raw material for the production of adsorbents.

[0051] Thus, the present invention addresses to a process to produce crude bio-oil from biomass with high moisture content, which comprises the following steps: [0052] a. Preparing the process feed by mixing water and residual lignocellulosic biomass to form a mixture containing from 5% to 20% by weight of dry biomass; and adding catalyst so that its concentration is from 1 to 10% m/m, in relation to the dry biomass. [0053] b. Hydrothermally liquefying (HTL) the mixture prepared in (a) by heating it to a temperature in the range of 250 to 300° C. at a pressure of 900 to 1300 psig (6.205 to 8.963 MPa). [0054] c. Cooling the mixture after the reaction is complete. [0055] d. Sending the formed products to a separator where the gaseous, solid, oily and aqueous streams, which contain the catalyst, are separated. [0056] e. Recycling the aqueous stream separated in (d) to the beginning of the process, in order to reuse the catalyst and reincorporate the oxygenated compounds into the reaction medium.

[0057] In a first aspect, the streams of replacement water, catalyst and biomass feed the liquefaction reactor.

[0058] In a second aspect, the oily stream obtained in step (d) consists of a bio-oil.

[0059] In a third aspect, the gaseous stream obtained in step (d) can be optionally recycled to the reactor to maintain a reducing atmosphere or undergo a membrane separation process to obtain syngas.

[0060] In a fourth aspect, the gaseous stream obtained in step (d) can generate energy by means of its total oxidation.

[0061] In a fifth aspect, the aqueous stream obtained in step (d) is recycled in order to reuse the catalyst and reinsert the water-soluble oxygenated compounds into the reaction medium.

[0062] In a sixth aspect, the oily stream obtained in step (d) is directed to processing in conventional oil refining units or to units dedicated to the improvement of the quality of bio-crude.

[0063] In a seventh aspect, the solid stream obtained in step (d) can be directed to a boiler in order to generate energy for the process or for the production of adsorbents.

[0064] In an additional aspect, the biomass content in the biomass+water mixture, described in step (a), is 5 to 20% m/m.

[0065] In a second additional aspect, the mentioned process produces an oily liquid stream, rich in renewable molecules, called bio-crude (or bio-oil), with lower oxygen content, lower percentage of water and lower acidity than the bio-crudes produced in thermochemical processes of biomass conversion.

[0066] In a third additional aspect, said process comprises a step of recovery and recycling of the catalyst in steps (d) and (e).

[0067] In a fourth additional aspect, the biomass is selected from the group consisting of: a biomass of any cellulosic material; lignin obtained from sugarcane bagasse by means of the acid hydrolytic process; any fatty material; any proteinaceous material or the mixture of two or more of the above-described materials.

[0068] In the process described above, the catalyst used is a homogeneous catalyst and consists mostly of potassium. The mentioned catalyst is used in a concentration of 1% to 10% w/w, in relation to the total weight of the biomass.

[0069] Further, with regard to the process described above, it should be noted that it is carried out by recycling the generated aqueous fraction, which contains the catalyst and some of the oxygenated products, so that the need for water replacement for the process is minimized, and that the catalytic activity is maintained with the concomitant incorporation of oxygenated compounds into the reaction medium, which results in an increase in the bio-oil yield.

[0070] In yet another inventive variant, the catalyst for hydrothermal liquefaction of biomass streams is obtained by means of the calcination, in boilers, of residues from the production of castor oil. The calcination is carried out at 600° C. and the castor oil production residues used are castor hull (epicarp+mesocarp).

[0071] In this variant, it is worth to note that the catalyst is a solid, easy to handle, non-toxic, with low production cost, reusable, with a high content of alkali metals (>50%) and high solubility in water, which enables its reuse and allows the process to recycle the entire formed aqueous fraction, drastically reducing water consumption and increasing the bio-oil yield by reincorporating the soluble oxygenated products in the aqueous fraction into the reaction medium, in addition to reinserting the catalyst in the same.

[0072] In a last inventive variant, the catalyst for hydrothermal liquefaction of biomass streams is defined as a catalyst that has liquefaction rates greater than 85% and oil stream yields greater than 40%, in which said process improves the bio-oil yield by at least 30% compared to the uncatalyzed process.

EXAMPLES

Example A

[0073] To carry out the liquefaction experiments, an autoclave reactor with temperature control was used. The moisture content of the biomass was determined and about 10 g of this material, on a dry basis, was added to the reactor. The amount of water was calculated by taking the water already present in the biomass into account. After loading water and biomass, the reactor was closed and purged with nitrogen.

[0074] Then the reactor was pressurized at 100 bar (10 MPa) for 1 h to check for tightness. After this step, the reactor was heated to the desired temperature. The residence time was counted from the moment the test temperature was reached. After the reaction time had elapsed, the heating was switched off and all thermal insulation was removed for fast system cooling. Conversion (X) (degree of liquefaction) and yields (Y) of bio-oil (BO) and char are calculated according to the equations below.

[00001]$X\left(\%\right)=\frac{\mathrm{Mbagaço}-\mathrm{Mchar}}{\mathrm{Mbagaço}}.Math.100Y_{\mathrm{BO}}\left(\%\right)=\frac{M_{\mathrm{BO}}}{\mathrm{Mbagaço}}.Math.100Y_{\mathrm{char}}\left(\%\right)=\frac{\mathrm{Mchar}}{\mathrm{Mbagaço}}.Math.100$

where M is the mass of the material.

[0075] Non-Catalyzed Hydrothermal Liquefaction

[0076] The non-catalyzed hydrothermal liquefaction tests were performed at 300° C. with 0 min residence time. The heating ramp time for this system was 60 minutes. After the first test, the aqueous fraction was separated and reused in the second test. The same procedure was performed for the third test.

[0077] It can be noted in Table 1 that, in the first test, a conversion close to 80% is achieved, with a bio-oil yield around 27%. However, with the reuse of the aqueous fraction, the conversion drops drastically, to levels of around 60%, which means an increase in the char yield to 20% in the first reuse and to 40% in the second reuse. Such effect is attributed to the presence of organic acids in the aqueous fraction, which can catalyze the formation of char. However, can be noted that the bio-oil yield is not affected by the recycle of the aqueous stream, remaining stable at 27%.

TABLE-US-00001 TABLE 1 BIO-OIL YIELD (%) CONVERSION (%) CHAR YIELD (%) 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd CATALYST INITIAL REUSE REUSE INITIAL REUSE REUSE INITIAL REUSE REUSE NON-CATALYZED 27.2 26.6 27.0 82 58 61 18 42 39 PROCESS

Example B

[0078] In example B, the same procedure detailed in example A was used, except for the use of the catalyst in the proportion of 5% m/m of the biomass on a dry basis, prepared from castor bean hull.

[0079] The catalyst was generated by means of the calcination of castor bean hull (7% inorganic content), in air flow at 600° C. for 6 h. The resulting product presented the composition of the table below, obtained by X-ray fluorescence technique.

TABLE-US-00002 TABLE 2 ORDER ANALYTE RESULT UNIT 1 K 51 % 2 Ca 6.9 % 3 Si 4.4 % 4 Al 2.6 % 5 Fe 2.2 %

[0080] It can be noted in Table 3 that, with the use of the catalyst, the initial conversion reaches a value of more than 90%, while the bio-oil yield reaches 36%. These values are higher than those observed for the non-catalyzed system (example A) and show the role of the catalyst in this reaction.

[0081] With the reuse of the aqueous fraction the yield of bio-oil rises to 43% and then to a value greater than 45%. This increase in the bio-oil yield indicates that the catalytic effect is maintained and that the oxygenated products are reincorporated when the aqueous stream is recycled. In addition, a possible effect of the organic acids present in the aqueous fraction on the catalysis of the char formation is mitigated, which is evidenced by the small drop in conversion.

TABLE-US-00003 TABLE 3 BIO-OIL YIELD (%) CONVERSION (%) CHAR YIELD (%) 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd CATALYST INITIAL REUSE REUSE INITIAL REUSE REUSE INITIAL REUSE REUSE PATENT 35.8 43.6 45.2 92 89 87 8 11 13 CATALYST

[0082] After the initial test, the generated solid fraction (char) was calcined and the inorganic residue obtained was submitted to an X-ray diffraction analysis in order to verify if the catalyst compounds were being concentrated in the solid residue. It can be seen in FIG. 2 that the diffraction pattern of the catalyst substantially differs from that observed for the inorganic compounds present in the char formed in the reaction, with the presence of catalyst. On the other hand, the diffraction pattern of the inorganics present in the char is very similar to that obtained for the inorganics present in the sugarcane bagasse. This observation leads to the conclusion that the inorganics present in the char come from the bagasse and not from the catalyst used in the test. The results corroborate the observation that the recycling of the aqueous stream promotes the return of the catalyst to the reaction medium.

Example C

[0083] In example C, the same procedure detailed in example B was used, however with the use of potassium carbonate PA as a catalyst. Table 04 shows a behavior similar to that obtained with the catalyst prepared from the calcination of castor bean hull. The results should be compared with examples A and B.

TABLE-US-00004 TABLE 4 BIO-OIL YIELD (%) CONVERSION (%) CHAR YIELD (%) 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd 1.sup.st 2.sup.nd CATALYST INITIAL REUSE REUSE INITIAL REUSE REUSE INITIAL REUSE REUSE PURE REAGENT 36.3 42.9 45.6 91 85 93 9 15 7 CATALYST

[0084] Table 05 summarizes the results obtained in examples A, B and C. It can be noted that the non-catalyzed process is the one with the lowest bio-oil yields and lower lignocellulosic raw material conversions. Furthermore, in this process, the reuse of the aqueous fraction allows the maintenance of the bio-oil yield at a stable level; however, the conversion undergoes a high reduction, with a concomitant increase in the yield of solid product (char).

[0085] With the use of the prepared catalyst, a significant increase in the yield of bio-oil can be noted, and the recycling of the aqueous phase allows, concomitantly, the reintroduction of the catalyst in the system, and also of organic compounds, so that the bio-oil yield is still high compared to what was initially observed.

[0086] Using the same process strategy, but with the use of a classic catalyst, there are obtained results that are very similar to those obtained with the prepared catalyst. However, it is worth to note that this catalyst is a highly pure reagent, unlike the catalyst presented in example B, which was prepared from lignocellulosic residues.

[0087] In this way, the advantages of using said catalyst together with the proposed process strategy remain clear, which can promote a high yield of bio-oil with lower catalyst cost and lower consumption of inputs.

TABLE-US-00005 TABLE 5 BIO-OIL YIELD (%) CONVERSION (%) CATALYST INITIAL 1.sup.st REUSE 2.sup.nd REUSE INITIAL 1.sup.st REUSE 2.sup.nd REUSE NON-CATALYZED PROCESS 27.2 26.6 27.0 82 58 61 PATENT CATALYST 35.8 43.6 45.2 92 89 87 PURE REAGENT CATALYST 36.3 42.9 45.6 91 85 93

[0088] It should be noted that, although the present invention has been described in relation to the drawings and examples, it may undergo modifications and adaptations by technicians skilled on the subject, depending on the specific situation, but provided that it is within the inventive scope as defined herein.