PROCESS OF OBTAINING A CATALYST, CATALYST AND PRE-TREATMENT PROCESS OF ACIDIC CHARGES

Abstract

The present invention concerns a catalyst and pre-treatment process for acidic charges consisting of sulfated zirconia and cerium for the production of biofuels, characterized in that the catalyst has greater activity and resistance to deactivation with acidic charges.

Claims

1. A PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES, characterized in that it comprises the following steps: a) precipitation of zirconium hydroxide using a source of zirconium and a base; b) addition of a porogen to the solution prepared in a); c) stirring, aging, filtering, drying; d) addition of a source of cerium and a source of sulfur over the dry material obtained in c); e) calcination of the material obtained in d); f) optionally, the addition of the porogen is carried out during the sulfation/incorporation of cerium in d), followed by calcination; g) optionally, addition of a source of titanium and sulfur followed by the addition of cerium in step d).

2. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the porogen added in step b) is starch or a surfactant.

3. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claims 1 and 2, characterized in that the selected surfactant is the copolymer of poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) with a ratio of 20:70:20.

4. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the source of zirconium is zirconium oxychloride or zirconium nitrate.

5. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the base is selected from ammonium hydroxide, or sodium carbonate, or sodium hydroxide.

6. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the source of cerium is cerium nitrate.

7. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the source of sulfur is ammonium sulfate.

8. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the source of titanium is titanium oxysulfate.

9. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the deposition is carried out by a method selected from wet spot impregnation, mud impregnation or chemical vapor phase deposition.

10. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 9, characterized in that the deposition is carried out by mud impregnation.

11. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the aging of step c) is carried out in pH in the range between 8 and 11, for a period of time of up to 24 hours, and dried at a temperature between 100 and 140° C., for a period between 10 and 24 hours.

12. THE PROCESS OF OBTAINING A PRE-TREATMENT CATALYST OF ACIDIC CHARGES according to claim 1, characterized in that the materials obtained in step e) are calcinated at a temperature of 350° C. to 800° C., for a period of time between 3 h and 10 h, using a heating rate between 1° C./min and 10° C./min.

13. A PRE-TREATMENT CATALYST OF ACIDIC CHARGES, characterized in that it is a solid acidic catalyst of sulfated zirconia/cerium or sulfated zirconia/cerium/titanium, with mass ratio Ce/Zr from 0.02 to 0.10 and Ti/Zr of 0.05 to 0.50, specific area between 70 and 120 m.sup.2/g, pore diameter between 40 and 80 Å, acidic strength between 0.9 and 1.5 ((μmol NH.sub.3/gcat)/(μmol C.sub.3H.sub.6/gcat)), acidic site density between 0.7 to 2.0 (μmol NH.sub.3/m.sup.2), sulfur content between 1.0 to 5.0% m/m, and obtained in a process as defined in the claims 1 to 12.

14. A PRE-TREATMENT PROCESS OF ACIDIC CHARGES, characterized in that it uses the solid acidic catalyst as defined in claim 13, and in that it is used in esterification reactions with fatty acids, mixtures of fatty acids and triglycerides, or bio-oil, in batch, in fed batch, or in continuous mode, in a fixed bed reactor.

15. THE PRE-TREATMENT PROCESS OF ACIDIC CHARGES as defined in claim 14, characterized in that it is carried out at temperatures from 50 to 120° C. for bio-oil charge and 50 to 150° C. for fatty acid charge, pressures from 1 to 25 bar (0.1 to 2.5 MPa), reaction time from 2 to 6 hours, alcohol/fatty acid molar ratio between 2 and 10, alcohol/bio-oil molar ratio between 2 and 8, and percentage of catalyst in relation to acidic charge from 1 to 8% m/m.

16. THE PRE-TREATMENT PROCESS OF ACIDIC CHARGES as defined in claim 15, characterized in that it uses aliphatic alcohols of low molecular weight, in the range of 1 to 4 carbon atoms.

17. THE PRE-TREATMENT PROCESS OF ACIDIC CHARGES as defined in claims 15 and 16, characterized in that it uses low molecular weight aliphatic alcohols, in the range of 1 to 4 carbon atoms, preferably methanol and ethanol.

18. THE PRE-TREATMENT PROCESS OF ACIDIC CHARGES as defined in claims 14 and 15, characterized in that the fatty acid is present in the mixture of fatty acid and triglycerides in a concentration between 0.05 to 99.5% m/m.

19. THE PRE-TREATMENT PROCESS OF ACIDIC CHARGES as defined in claims 14 to 17, characterized in that the bio-oil comes from processes of pyrolysis of plant biomass in the absence of oxygen, with temperatures between 400 and 550° C.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0015] 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 thereof. In the drawings, there are:

[0016] FIG. 1 shows a graph of the average diameter of the catalyst versus the conversion (60° C./R=10/180 min, using a standard charge of 85% oleic acid+15% soybean oil), where 1 and 2 are the reference catalysts 1 and 2, respectively, and the catalysts obtained with porogens (an agent that increases porosity, by means of the removal by calcination, or extraction) are represented by the letters A to E, whose preparation is shown in the examples 1 to 3.

[0017] FIG. 2 shows acidic strength versus the conversion (60° C./R=10/180 min, using a standard charge of 85% oleic acid+15% soybean oil), where 1 and 2 are the reference catalysts 1 and 2, respectively, and the catalysts obtained with porogens are represented by the letters A to E, whose preparation is shown in examples 1 to 3.

[0018] FIG. 3 shows the density of acidic sites versus the conversion (60° C./R=10/180 min, using a standard charge of 85% oleic acid+15% soybean oil), where 1 and 2 are the reference catalysts 1 and 2, respectively, and the catalysts obtained with porogens are represented by the letters A to E, whose preparation is shown in examples 1 to 3.

DETAILED DESCRIPTION OF THE INVENTION

[0019] Preliminarily, it is noted that the description that follows will start from preferred embodiments of the invention. As will be apparent to any technician skilled on the subject, however, the invention is not limited to these particular embodiments, but only to the scope of protection defined in the claims.

[0020] The catalyst of the present invention is obtained by introducing the active phases of cerium, or titanium and sulfur in the zirconium-based catalyst, which can be introduced separately or simultaneously.

[0021] Thus, according to an embodiment of the invention, the process for obtaining the catalysts according to the present invention comprises the following steps: [0022] a) precipitation of zirconium hydroxide using a source of zirconium and a base; [0023] b) addition of a porogen to the solution prepared in a); [0024] c) stirring, aging, filtering, drying; [0025] d) addition of a source of cerium and a source of sulfur over the dry material obtained in c); [0026] e) calcination of the material obtained in d); [0027] f) optionally, the addition of the porogen is carried out during the step of sulfation and cerium incorporation in d), followed by calcination; [0028] g) optionally, addition of a source of titanium and sulfur followed by the addition of cerium in step d).

[0029] The source of zirconium can be zirconium oxychloride or zirconium nitrate, and the base can be ammonium hydroxide, or sodium carbonate, or sodium hydroxide. The source of cerium may be cerium nitrate. The source of sulfur can be ammonium sulfate. In this way, a low sulfur zirconium/cerium catalyst is obtained. The deposition takes place by a method selected from wet spot impregnation, mud impregnation or chemical vapor phase deposition, preferably by mud impregnation. Aging is carried out at a pH in the range between 8 and 11, for a period of time of up to 24 hours, and dried at a temperature between 100 and 140° C., for a period of between 10 and 24 hours. The calcination step takes place at a temperature between 350° C. and 800° C., for a period between 2 h and 10 h, using a heating rate between 1° C./min and 10° C./min.

[0030] The catalysts thus obtained have a Ce/Zr mass ratio: 0.02 to 0.10; Ti/Zr=0.05 to 0.50; and sulfur content in the range of 1.0 to 5.0% m/m.

EXAMPLES

[0031] Next, in order that the invention can be better understood, experiments that illustrate the invention are presented, without, however, being considered limiting.

Example 1

[0032] A: in the first step, the precipitation of zirconium hydroxide was made using Zr oxychloride (1 M) and NH.sub.4OH (14.5% m/m), at room temperature, pH in the range of 10 to 11, dripping the precursor of Zr under ammonium hydroxide for 60 minutes. After the addition of the precursor, corn starch was preferably incorporated, and the porogen may originate from other sources such as: potato, yam, arrowroot, banana, among others (35% m/m in relation to the desired amount of ZrO.sub.2); the sample remained for 1 hour under stirring, followed by aging for 22 hours, washing/filtering and drying at 100° C. for 16 hours.

[0033] With the dry material, the impregnation was made with cerium nitrate and ammonium sulfate (Ce/Zr=0.05 and 6.5% m/m of ammonium sulfate in relation to the ZrO.sub.2) simultaneously in zirconium hydroxide (mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1). The mud was stirred for 24 hours at 300 rpm. After this step, the sample was dried at 100° C. for 24 hours in a fluidized bed reactor with air flow, followed by calcination at 600° C. for 5 h using 3° C./min using air flow rate (40 cm.sup.3/min).

[0034] B: in this preparation, the porogen incorporation was made during the sulfation/incorporation of cerium in zirconium hydroxide prepared previously by precipitation (6.5% m/m ammonium sulfate, Ce/Zr=0.05, mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1, and 42% m/m corn starch in relation to ZrO.sub.2). Note that starch can come from other sources such as: potato, yam, arrowroot, banana, among others. The step was carried out at 25° C. for 24 hours at 300 rpm. After this step, the sample was dried at 100° C. for 24 hours in a fluidized bed reactor with air flow, followed by calcination at 600° C. for 5 h, using 3° C./min, using air flow rate (40 cm.sup.3/min).

[0035] C: In the first step, the precipitation of zirconium hydroxide was made using Zr oxychloride (1 M) and NH.sub.4OH (14.5% m/m), pH in the range of 10 to 11, at room temperature. After the addition of the precursor, corn starch was incorporated (17.5% m/m in relation to the desired amount of ZrO.sub.2), the sample remained for 1 hour under stirring, followed by aging for 22 hours, washing/filtering and drying at 100° C. for 16 hours.

[0036] With the dry material, the impregnation was made with cerium nitrate and ammonium sulfate (Ce/Zr=0.05 and 6.5% m/m of ammonium sulfate in relation to ZrO.sub.2) simultaneously in zirconium hydroxide (mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1). The mud was stirred for 24 hours at 300 rpm. After this step, the sample was dried at 100° C. for 24 hours in a fluidized bed reactor with air flow, followed by calcination at 600° C. for 5 h using 3° C./min using air flow rate (40 cm.sup.3/min).

Example 2

[0037] This example illustrates the catalyst preparation using an EO-PPO-PEO triblock copolymer (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) copolymer) with ratio 20:70:20) with 20:70:20 (EO:PO:EO), as a porogen.

[0038] D: In the first step, the precipitation of zirconium hydroxide was made using Zr oxychloride (1 M) and NH.sub.4OH (14.5% m/m), pH in the range of 10 to 11, at room temperature, dripping the precursor of Zr under ammonium hydroxide for 60 minutes. After the addition of the precursor, the EO-PPO-PEO triblock copolymer (35% m/m in relation to the desired amount of ZrO.sub.2) was incorporated, the sample remained for 1 hour under stirring, followed by aging for 22 hours, washing/filtration and drying at 100° C. for 16 hours.

[0039] With the dry material, the impregnation was made with cerium nitrate and ammonium sulfate (Ce/Zr=0.05 and 6.5% m/m of ammonium sulfate in relation to ZrO.sub.2) simultaneously in zirconium hydroxide (mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1). The mud was stirred for 24 hours at 300 rpm. After this step, the sample was dried at 100° C. for 24 hours in a fluidized bed reactor with air flow, followed by calcination at 600° C. for 5 h using 3° C./min using air flow rate (40 cm.sup.3/min).

[0040] E: Zirconium hydroxide was obtained by precipitation with ammonium hydroxide, at room temperature and at controlled pH (9 to 10) by dripping zirconium oxychloride (1.5 M) for 40 minutes over the solution of ammonium hydroxide (14.5% m/m). At the end of the precursor addition, EO-PPO-PEO triblock copolymer (6.7% m/m in relation to ZrO.sub.2) was added, the system aged at room temperature for 21 hours, being filtered and washed with deionized water, and then dried in a static atmosphere at 120° C. for 16 hours.

[0041] With the dry material, the sulfation was made with titanium oxysulfate and ammonium sulfate (Ti/Zr=0.18 and 6.5% m/m of ammonium sulfate in relation to ZrO.sub.2), with mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1. The mud was stirred for 24 hours at 300 rpm. After this step, the sample was calcined at 600° C. for 5 h using 3° C./min using air flow rate (40 cm.sup.3/min). After this step, the solid was impregnated with cerium nitrate (Ce/Zr=0.035) in excess of solution, for 2 hours at room temperature with stirring. The solid was dried at 40° C. for 16 h and calcined with air flow 40 cm.sup.3/min at 400° C. for 4 hours, using a rate of 3° C./min.

Example 3

[0042] This example illustrates the preparation of catalysts without the use of a porogen.

Reference 1 (1)

[0043] Zirconium hydroxide was obtained by precipitation with ammonium hydroxide, at room temperature and at controlled pH (9 to 10) by dripping zirconium oxychloride (1.5 M) for 40 minutes over the solution of ammonium hydroxide (14.5% m/m). The system was aged at room temperature for 21 hours, being filtered and washed with deionized water, and then dried in a static atmosphere at 120° C. for 16 hours.

[0044] With the dry material, the sulfation was made with ammonium sulfate (6.5% m/m of ammonium sulfate in relation to ZrO.sub.2), with a mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1. The mud was stirred for 24 hours at 300 rpm. After this step, the sample was calcined at 600° C. for 5 h using 3° C./min using air flow rate (40 cm.sup.3/min). After this step, the solid was impregnated with cerium nitrate (Ce/Zr=0.05) in excess of solution, for 2 hours at room temperature with stirring. The solid was dried at 40° C. for 16 h and calcined with an air flow of 40 cm.sup.3/min at 400° C. for 4 hours, using a rate of 3° C./min.

Example 4

[0045] This example illustrates the preparation of catalysts without the use of a porogen.

Reference 2 (2)

[0046] Zirconium hydroxide was obtained by precipitation with ammonium hydroxide, at room temperature and at controlled pH (9 to 10) by dripping zirconium oxychloride (1.5 M) for 40 minutes over the solution of ammonium hydroxide (14.5% m/m). The system was aged at room temperature for 21 hours, being filtered and washed with deionized water, and later dried in a static atmosphere at 120° C. for 16 hours.

[0047] With the dry material, sulfation was performed with titanium oxysulfate and ammonium sulfate (Ti/Zr=0.18 and 6.5% m/m of ammonium sulfate in relation to ZrO.sub.2), with mass ratio H.sub.2O:Zr(OH).sub.x:2.4:1. The mud was stirred for 24 hours at 300 rpm. After this step, the sample was calcined at 600° C. for 5 h using 3° C./min using air flow (40 cm.sup.3/min). After this step, the solid was impregnated with cerium nitrate (Ce/Zr=0.035) in excess of solution, for 2 hours at room temperature with stirring. The solid was dried at 40° C. for 16 h and calcined with an air flow of 40 cm.sup.3/min at 400° C. for 4 hours, using a rate of 3° C./min.

Example 5

[0048] This example illustrates the characterization results and reaction tests.

[0049] Table 1 shows that the changes in the preparation of catalysts A to E provided an increase in acidic properties in relation to the catalyst Reference 1 (1). The results can be analyzed as follows: [0050] a) density of acidic sites (Bronsted acidity/surface area ratio); the order was as follows: E>A>D>C>B>Reference 2>Reference 1 (1). [0051] b) acidic strength had the following order: D>C>Reference 2>A>E>B>Reference 1 (1). It can be evaluated by the ratio of moles of ammonia/gcat by moles of propene/gcat obtained in the n-propylamine TPD assay.

[0052] Table 2 presents the textural results of the series of catalysts studied, showing the increase of macropores in the samples with the use of porogens.

TABLE-US-00001 TABLE 1 Acidity results n-propylamine TPD Density of acidic Acidic strength sites (μmol ((μmol.sub.NH3/gcat)/ Catalysts NH.sub.3/m.sup.2) (μmol.sub.C3H6/gcat)) Reference 1 (1) 0.95 0.71 A 1.39 1.35 B 1.03 1.10 C 1.35 1.42 Reference 2 (2) 0.99 1.36 D 1.37 1.59 E 1.77 1.11 Note: TPD—temperature programmed desorption.

TABLE-US-00002 TABLE 2 Results of textural characterization. A.sub.BET D.sub.pore Catalyst (m.sup.2/g) *(Å) Porosity Type Reference 1 (1) 100 75 Mesoporous A 115 54 Mesopores and evidence of the presence of macropores B 86 59 Predominantly mesoporous C 96 38 Mesoporous and evidence of the presence of macropores D 102 36 Mesoporous, with presence of micropores and macropores E 83 49 Mesoporous with a predominance of macropores Reference 2 (2) 144 51 Mesoporous Note: *Referring to the BJH desorption curve.

[0053] FIG. 1 shows the test results in the selected condition: 60° C./R=10/180 min, using a standard charge of 85% oleic acid+15% soybean oil, where R=molar ratio between charge and methanol, considering the fatty chain that can be esterified into the glyceride. All catalysts showed conversions above the blank conversion (in the absence of catalyst) equal to 11%. It is observed that despite the Reference 1 catalyst having a larger pore diameter, the conversion found was extremely low, being related to the low acidity of the sample (lower acidic strength and density of Bronsted acidic sites). The reactions can be carried out in continuous processes, or in batch, or in fed batch. The reactions are preferably carried out in a continuous process in a plug-type fixed bed flow reactor (“PFR—plug flow reactor”). The process is carried out at temperatures from 50 to 120° C. for bio-oil charge and 50 to 150° C. for fatty acid charge, pressures from 1 to 25 bar (0.1 to 2.5 MPa), reaction time from 2 to 6 hours, alcohol/fatty acid molar ratio between 2 and 10, alcohol/bio-oil molar ratio between 2 and 8, and percentage of catalyst in relation to acidic charge from 1 to 8% m/m.

[0054] Additionally, all samples from A to D had higher conversions than the reference catalysts, even D and C, which had smaller average diameters than the reference catalysts, as can be seen in FIG. 1.

[0055] FIGS. 2 to 3 show that the results are directly correlated with acidic properties (Bronsted acidity and acidic strength). The catalysts with the presence of macropores, A, D and C, have the highest conversion results, showing that the procedure was able to produce more active catalysts with the use of porogens in relation to Reference catalysts 1 and 2, as can be seen in Table 2. It is considered that the best result found was obtained for sample C, since it has high activity, with the presence of macropores and high density of acidic sites. In addition, the preparation took less starch in its formulation.

[0056] The percentage of the catalyst in relation to the acidic charge is from 1 to 8% m/m, both for fatty acids or mixtures of fatty acids with triglycerides and for bio-oil charge.

[0057] Therefore, the catalyst can be used in the pre-treatment of acidic charges such as fatty acids, mixtures of fatty acids with triglycerides and bio-oil. The mixtures of fatty acids with triglycerides have contents of 0.05 to 99.5% m/m of fatty acid in the mixture. The alcohols used in this process are low molecular weight aliphatic alcohols, ranging from 1 to 4 carbon atoms, preferably methanol and ethanol.

[0058] The catalyst can also be used with bio-oil, which comes from pyrolysis processes in the absence of oxygen, at temperatures from 400 to 600° C. Bio-oil comes from plant biomass, such as sugarcane bagasse, sugarcane straw, wood, rice husk, waste from the paper industry such as black liquor, etc.

[0059] Note that the esterification reaction occurs naturally during the aging of bio-oil. Esterification, transesterification and acetalization reactions with alcohols decrease the content of carboxylic acids, ketones and aldehydes, transforming them into esters and acetals (Lu, J., Guo, S., Fu, Y., Chang, J., Fuel Processing Technology 161: 193-198, 2017). These reactions can occur, to some extent, promoted by acidity and storage temperature, and can even happen at room temperature (Diebold, J. P., NREL/SR-570-27613). Controlled esterification can be used in a pre-treatment of bio-oil, allowing the partial removal of oxygenated compounds, increasing the useful life of HDO catalysts, consequently reducing the severity of the reaction, enabling the use of renewable charges in refining.