Processing biomass to produce transport biofuels is a sustainable option to consolidate alternati... more Processing biomass to produce transport biofuels is a sustainable option to consolidate alternative energy sources with worldwide growing interest. The production of bio-oil from the pyrolysis of lignocellulosic wastes from various sources is particularly attractive, due to the low cost of raw materials and to the fact that it does not compete with food production. Bio-oil production and characterization activities planned for and executed with secondary grade students are presented in this work; experiments were simple and performed with very low cost materials. Students learnt to use basic instruments for data acquisition and the experimental results, that can be compared with those obtained with conventional and sophisticated techniques, were analyzed critically. It is to be mentioned that the degree of compromise shown by the students was very high. Pine wood resulted the most convenient for the production of liquid fuels, because their yield were higher and the physicochemical properties of the bio-oil were the best, specially their higher heating value and H/C ratio.
Advances in Feedstock Conversion Technologies for Alternative Fuels and Bioproducts, 2019
Abstract Disposing livestock wastes from concentrated animal feeding operations represents a prob... more Abstract Disposing livestock wastes from concentrated animal feeding operations represents a problem from both economic and environmental care views, but it is possible to process them in thermochemical processes. The pyrolysis of cow manure was studied, with emphasis on the characterization of products. When the pyrolysis temperature increased from 550°C to 650°C, hydrocarbons yields increased 33% and char yields decreased 90%. Tar (the liquid product with the highest energy density) yields increased from 22 to 35 wt.%, and biooil (the product containing the highest amount of chemical compounds) yields were constant at about 27 wt.%. The biooil contained mainly acids, ketones, and furans, typical in the pyrolysis of cellulose, hemicellulose, and lignin, while the tar contained mainly alcohols and long-chain esters, derived from depolymerization and cracking of lipids and proteins. In comparison with other raw biomasses more extensively studied, cow manure produced much more tar, which could be important in, for example, bioasphalt formulations.
Avances en Energías Renovables y Medio Ambiente, 2009
The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) wa... more The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) was studied under nitrogen flow. The bio-oils were produced in a fixed-bed reactor at 550 ºC, with a heating ramp of 15 ºC/min. The highest bio-oil yield (39 %) was obtained with pine sawdust. The bio-oils were analyzed by GC/MS after fractioning with water and ether. The different fractions contained mainly aldehydes, cetones and phenols. The effect of a thermal treatment over the composition of the bio-oils was studied in order to assess the changes that could help to co-process them in existing, conventional refineries, due to their high coking potential. The thermal treatment was performed under a heating ramp of 12 ºC/min and final temperature of 500 ºC. This treatment induced a strong decrease in the CCR, of about 70 %, and a slight increase in the content of water.
Taverna, Maria Eugenia (1,2); Polo, Mara Lis. (2); Zocola, Maria Evangelina (3); Bertero, Melisa ... more Taverna, Maria Eugenia (1,2); Polo, Mara Lis. (2); Zocola, Maria Evangelina (3); Bertero, Melisa (3) (1) UTN Regional San Francisco, Av. de la Universidad 501, (2400) San Francisco, Cordoba, Argentina. (2) INTEC (UNL-CONICET), Guemes 3450, (3000) Santa Fe, Argentina. (3) INCAPE (UNL– CONICET) Colectora Ruta Nac. No 168 Km 0 – Paraje El Pozo (3000) Santa Fe, Argentina.
Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Ci... more Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto de Investigaciones en Catalisis y Petroquimica ; Argentina
Sustainable Technologies for the Management of Agricultural Wastes, 2017
Palm kernel shell (PKS) and empty fruit bunches, both raw (EFB-R) and pretreated by means of auto... more Palm kernel shell (PKS) and empty fruit bunches, both raw (EFB-R) and pretreated by means of autoclaving (EFB-A) and microwave (EFB-M), were pyrolyzed in a fixed-bed stainless steel reactor at 550 °C. The yield of the water-soluble liquid fraction (pyroligneous acid, PA) in the pyrolysis of PKS was 26%wt. (dry basis) and in the range of 16–46%wt. when different EFB were used. The yield of insoluble liquid fraction (bio-oil, BO) was 9.1%wt. for PKS and up to 25%wt. in the case of EFB. Liquid and gaseous products were analyzed by conventional capillary gas chromatography. The PA from the PKS had 30%wt. of total phenolic compounds (up to 24%wt. phenol) and 46%wt. acetic acid. On the other hand, the bio-oil from PKS had 43%wt. of total phenolic compounds (up to 26%wt. phenol) and 17%wt. acetic acid. The PA from EFB contained mainly acetic acid (65.5%wt.), furfural (7.7%wt.), methanol (8.0%wt.), and phenol (15.2%wt.). When EFB was pretreated, the concentration of acetic acid in PA decreased dramatically, while the concentration of furfural increased up to ten times, this effect being more noticeable in the case of microwave pretreatment. The yields of by-products were of significance in all cases (13–23%wt. of gases and 33–52%wt. of char). These results show that the liquid products obtained from the pyrolysis of palm oil industrial wastes could be used in order to obtain chemical raw materials of worldwide extended use, while the by-products (gases and char) can be used as renewable energy sources.
The immediate catalytic conversions of pyrolytic bio-oils from pine sawdust and soybean shell ove... more The immediate catalytic conversions of pyrolytic bio-oils from pine sawdust and soybean shell over mesoporous catalysts (silica, alumina, and silica-alumina) and their combinations with Y zeolite, were studied. The effect of mesoporosity and acidity on the bio-oil deoxygenation and conversion into hydrocarbons was investigated. Pyrolysis and immediate catalytic conversion of bio-oil were performed in an integrated pyrolysis–upgrading reactor, for 7 min under a 30-ml/min flow of nitrogen at 550 °C. Important differences were observed in the conversion of the bio-oils, according to the composition of the raw biomasses. Pine sawdust bio-oil produced more coke and less hydrocarbons in the range of gasoline than soybean shell bio-oil over all the catalysts. Mesoporous catalysts showed conversion and deoxygenation between 14 and 29 percentage points higher with the more acidic solid (SiO2-Al2O3) in the case of pine sawdust bio-oil and between 2 and 10 percentage points higher with the solid having the highest specific surface area (SiO2) in the case of soybean shell bio-oil. Among the compound catalysts, the best performance for the case of pine sawdust corresponded to the catalyst with the highest mesoporosity (Y/SiO2), while for soybean shell corresponded to the most acidic catalysts (Y/Al2O3 and Y/SiO2-Al2O3). Soybean shell bio-oil showed more low molecular weight compounds (less than 130 g mol−1), which diffuse more easily in the zeolite channels, thus favoring conversion and deoxygenation mechanisms. On the contrary, for pine sawdust bio-oil, the surface area contributed by the mesopores in the matrix played a key role in pre-cracking bulky molecules.
Spartina argentinensis, Panicum prionitis, and Arundo donax are perennial grasses and Geoffroea d... more Spartina argentinensis, Panicum prionitis, and Arundo donax are perennial grasses and Geoffroea decorticans is a shrub, all of which grow under adverse conditions in the Litoral region in Argentina. The pyrolytic conversion of these biomasses was studied at 550 °C in a fixed bed reactor during 30 min under N 2 flow with a 20 °C min −1 heating ramp starting at room temperature. The main products were liquid, two phases (aqueous and oil) being observed with the aqueous phases being the most important in all the cases (yields from 29.2 to 45.7 wt%). The highest yield for an oil phase (18 wt%) was observed with the shrub and the yield of gases and chars were similar in all the cases. By means of sequential vacuum distillation I was possible to selectively separate water, methanol and acetic acid which were present in the aqueous phases, thus increasing the concentration of high value compounds such as ketones, phenols and furans in the residual fraction. The concentration of phenolic compounds in the residual fraction was 60% higher than the initial one in the aqueous phase. The oil phase mainly contained phenols, ketones and acids with high molecular weight. According to these results, these biomasses can be considered as a source of energy, fuels or chemicals, and it is possible to propose a methodology to upgrade the aqueous fractions in pyrolysis liquids.
Oxygenated model compounds representing typical components of bio-oils and a hydrocarbon hydrogen... more Oxygenated model compounds representing typical components of bio-oils and a hydrocarbon hydrogen donor agent were used to study hydrogen transfer reactions between hydrocarbons and oxygenated compounds when co-processed over acidic commercial FCC catalysts. Phenol, syringol, and trimethoxybenzene were each mixed with tetralin at 5 wt%. individually in benzene as an inert solvent. The mixtures were reacted in a fluidized bed, batch CREC Riser Simulator laboratory reactor during 10 s contact time with catalyst to oil relationship of 3 at 500 ºC over a commercial equilibrium FCC catalyst, conditions being selected in order to simulate FCC bio-oil-VGO co-processing. Tetralin was also reacted alone at 5 wt%. in benzene to gather background information. When tetralin was the only reactant, its conversion was 87 %, most important
Changes were produced by means of alkaline lixiviation in the porosity of an equilibrium commerci... more Changes were produced by means of alkaline lixiviation in the porosity of an equilibrium commercial FCC catalyst formulated to maximize the yield of middle distillates, in order to improve its performance in the conversion of tar from the pyrolysis of cow manure into hydrocarbons. The pyrolysis was produced at 650 °C in a fixed bed reactor and the tar was catalytically upgraded, comparing the performances of the parent and modified catalysts under realistic FCC conditions, in a CREC Riser Simulator reactor at 550 °C during 10 s, catalyst to reactant relationships being 3, 5 and 8. The alkaline treatment increased both acidity and average mesopore size of the commercial catalyst, thus favoring the diffusion process of the bulkiest oxygenated molecules in tar. The modified catalyst was more effective in deoxygenating tar (conversions up to 87.5% and deoxygenation up to 74.6%), producing more hydrocarbons and coke than the parent catalyst. According to the chemical nature of the pyrolitic tar from cow manure, a high proportion of paraffins derived from the primary cracking of its components were observed among the product hydrocarbons in the gasoline range over both catalysts.
A commercial equilibrium FCC catalyst of the octane-barrel type was subjected to lixiviation trea... more A commercial equilibrium FCC catalyst of the octane-barrel type was subjected to lixiviation treatments with both acidic (HNO 3) and basic (NaOH) solutions in order to modify its textural and acidic properties. The alkaline lixiviation doubled the mesopore volume in the commercial catalyst, while the acidic treatment increased the concentration of crystalline component in the catalyst. The catalytic performances of the parent and modified catalysts in the immediate conversion of vapors from pine sawdust fast pyrolysis were evaluated in a fixed bed reactor at 550 ºC using mass catalyst to biooil ratios from 3 to 8. The modified catalysts both produced more hydrocarbons and less coke than the parent commercial catalyst. In turn, comparing the modified samples, the one subjected to alkali treatment was more effective in deoxygenating the pyrolysis vapors, resulting in higher hydrocarbon yields (up to 13.2 %) and lower coke yields than the acid modified catalyst, a fact assigned to the higher mesoporosity which improves the diffusion transport of bulky coke precursor molecules. The acid modified catalyst allowed a higher extension of the reaction pathway, the selectivity to aromatic hydrocarbon products being much higher (up to 95.5 % of hydrocarbons in the gasoline boiling range).
Matrices of FCC catalysts with different content of alumina and the compound catalysts prepared w... more Matrices of FCC catalysts with different content of alumina and the compound catalysts prepared with them including Y zeolite were used to upgrade bio-oils from pine wood sawdust and soybean shell. The biomasses were selected according to their different lignin content which results in very different proportions of phenolic compounds (coke precursors) in the respective bio-oils. The bio-oils were produced by fast pyrolysis and the vapours were immediately upgraded over a fixed bed of catalyst at 550 °C using a mass catalyst/bio-oil relationship of 3.5. In terms of hydrocarbon yield, the matrices were more effective in deoxygenating pine wood sawdust bio-oil and the compound catalysts in deoxygenating soybean shell bio-oil. These differences can be the consequence of the different compositions of the bio-oils which, in the case of pine wood sawdust, includes a significant concentration of phenolic ethers which form coke on the matrix and the external surface of the zeolite, thus preventing lighter compounds from accessing the micropore system of the compound catalysts. Pine sawdust bio-oil produced more coke than soybean shell bio-oil; in the case of compound catalysts, coke deposited preferentially on the catalyst matrix, thus decreasing its mesopore specific surface area up to 65 %.
The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equil... more The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equilibrium FCC catalyst was studied in order to define its potential as a source for fuels and chemicals. The experiments of pyrolysis and immediate catalytic upgrading were performed at 550 °C during 7 min with different catalysts to oil relationships in an integrated fixed bed pyrolysis-conversion reactor. The results were compared under the same conditions against those from pine sawdust, which is a biomass source commonly used for the production of bio-oil. In the pyrolysis the pine sawdust produced more liquids (61.4%wt.) than the soybean shell (54.7%wt.). When the catalyst was presented, the yield of hydrocarbons increased, particularly in the case of soybean shell, which was four time higher than in the pyrolysis. The bio-oil from soybean shell produced less coke (between 3.1 and 4.3%wt.) in its immediate catalytic upgrading than that from pine sawdust (between 5 and 5.8%wt.), due to its lower content of phenolic and other high molecular weight compounds (three and five times less, respectively). Moreover, soybean shell showed a higher selectivity to hydrocarbons in the gasoline range, with more olefins and less aromatic than pine sawdust.
Recent Advances in Thermo-Chemical Conversion of Biomass, 2015
Coprocessing bio-oils with conventional hydrocarbon feedstocks in the Fluid Catalytic Cracking (F... more Coprocessing bio-oils with conventional hydrocarbon feedstocks in the Fluid Catalytic Cracking (FCC) process in refineries is an interesting option for the production of fuel and petrochemical raw materials. The previous upgrading of bio-oils with a thermal treatment allows decreasing the content of coke precursors and improving their processing characteristics. The coprocessing of crude and upgraded bio-oil with vacuum gas oil (VGO) was studied in a CREC Riser Simulator reactor under typical commercial FCC conditions. It was observed that the addition of oxygenated feedstock (e.g., up to 5 wt%) did not affect the product distribution significantly. Coke yields in coprocessing were even lower than in the conversion of VGO alone, due to the simultaneous addition of water.
Y zeolite was desilicated by means of alkaline treatments (NaOH 0.05, 0.10 and 0.20 M) during 15 ... more Y zeolite was desilicated by means of alkaline treatments (NaOH 0.05, 0.10 and 0.20 M) during 15 min to produce varying mesoporosity over it. Catalysts were made with a SiO 2 matrix and a binder. Pine sawdust bio-oil was produced by pyrolysis and immediately upgraded on a bed of the compound catalysts. The experiments were produced in a fixed bed reactor at 550 ºC using different catalyst to reactants relationships. The desilicated zeolites were more effective than the parent zeolite to deoxygenate bio-oil and produce more hydrocarbons, with higher selectivity to olefins (more than 35 %wt.) and lower selectivity to aromatics (less than 60 %wt.) in gasoline. The selectivity to C4and gasoline olefins increased if the mesoporosity was higher, and the coke formed was less condensed. These observations were the result of improvements in the diffusion of bulky molecules in bio-oils, such as phenolic ethers, increasing their conversion to hydrocarbons.
Reactivity and product distributions in the conversion of five different compounds representing t... more Reactivity and product distributions in the conversion of five different compounds representing typical species in bio-oils were studied over an equilibrium FCC catalyst at 500 °C during 60 s in a fixed bed reactor. Acetic acid, methyl acetate, furfural, 3-methyl-2-pentanone and 2-hidroxy-3-methylcyclopentenone were dissolved at 5% wt. in water. Thermal conversions were performed under the same conditions with inert SiC in the bed. The test compounds converted very differently, deoxygenation being produced by decarboxylation and dehydration. Furfural and 3-methyl-2-pentanone gave the highest yields of hydrocarbons, with high selectivity to light olefins and, when liquid (case of ketones), to aromatics. Methyl acetate gave the highest yield of oxygenated compounds. Coke yields were important (maximum 12.8% wt., 2-hidroxy-3-methylcyclopentenone). Thermal conversions were similar to the catalytic ones with acetic acid and methyl acetate, and much lower for the other reactants. Compared catalytic experiments, the thermal yields of hydrocarbons were much higher with acetic acid, and the yields of oxygenated higher with methyl acetate ester. Much less hydrocarbons were produced thermally with the other reactants. This information may be useful for predicting contributions if these compounds are to be co-processed in existing FCC units or upgraded over acidic catalysts.
Bio-oils from different residual biomass raw materials (pine wood, mesquite wood and wheat shell)... more Bio-oils from different residual biomass raw materials (pine wood, mesquite wood and wheat shell) were produced by means of conventional pyrolysis at a temperature of 550°C during 60 min. Bio-oils were separated from gases, tar and char, to show yields between about 30 wt.% and 45 wt.%, and fractionated into water-and ether-soluble fractions in order to know their compositions. Gas chromatography-mass spectrometry was used to identify compounds and complemented with elemental analysis and Conradson carbon residue (CCR), together with water content, density and pH assessments. The composition of the bio-oils varied according to the source biomass. Compounds were considered in eleven main groups: acids, esters, linear aldehydes and ketones, cyclic ketones, furans, alcohols and sugars, phenols, other oxygenated cyclic compounds, hydrocarbons, ethers and nitrogen compounds. The physicochemical properties of bio-oils suggested that it is necessary to upgrade them before co-processing in conventional refining units such as those of catalytic cracking of hydrocarbons. Thermal pre-treatments were conducted with the aim of reducing the CCR of the bio-oils, resulting in a significant average 70% reduction. The concentration of coke precursor phenolic compounds, mainly phenolic ethers, was reduced between 7% and 25%. Another important consequence was the increase in the effective hydrogen index of the mixture, suggesting higher processability in FCC.
Processing biomass to produce transport biofuels is a sustainable option to consolidate alternati... more Processing biomass to produce transport biofuels is a sustainable option to consolidate alternative energy sources with worldwide growing interest. The production of bio-oil from the pyrolysis of lignocellulosic wastes from various sources is particularly attractive, due to the low cost of raw materials and to the fact that it does not compete with food production. Bio-oil production and characterization activities planned for and executed with secondary grade students are presented in this work; experiments were simple and performed with very low cost materials. Students learnt to use basic instruments for data acquisition and the experimental results, that can be compared with those obtained with conventional and sophisticated techniques, were analyzed critically. It is to be mentioned that the degree of compromise shown by the students was very high. Pine wood resulted the most convenient for the production of liquid fuels, because their yield were higher and the physicochemical properties of the bio-oil were the best, specially their higher heating value and H/C ratio.
Advances in Feedstock Conversion Technologies for Alternative Fuels and Bioproducts, 2019
Abstract Disposing livestock wastes from concentrated animal feeding operations represents a prob... more Abstract Disposing livestock wastes from concentrated animal feeding operations represents a problem from both economic and environmental care views, but it is possible to process them in thermochemical processes. The pyrolysis of cow manure was studied, with emphasis on the characterization of products. When the pyrolysis temperature increased from 550°C to 650°C, hydrocarbons yields increased 33% and char yields decreased 90%. Tar (the liquid product with the highest energy density) yields increased from 22 to 35 wt.%, and biooil (the product containing the highest amount of chemical compounds) yields were constant at about 27 wt.%. The biooil contained mainly acids, ketones, and furans, typical in the pyrolysis of cellulose, hemicellulose, and lignin, while the tar contained mainly alcohols and long-chain esters, derived from depolymerization and cracking of lipids and proteins. In comparison with other raw biomasses more extensively studied, cow manure produced much more tar, which could be important in, for example, bioasphalt formulations.
Avances en Energías Renovables y Medio Ambiente, 2009
The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) wa... more The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) was studied under nitrogen flow. The bio-oils were produced in a fixed-bed reactor at 550 ºC, with a heating ramp of 15 ºC/min. The highest bio-oil yield (39 %) was obtained with pine sawdust. The bio-oils were analyzed by GC/MS after fractioning with water and ether. The different fractions contained mainly aldehydes, cetones and phenols. The effect of a thermal treatment over the composition of the bio-oils was studied in order to assess the changes that could help to co-process them in existing, conventional refineries, due to their high coking potential. The thermal treatment was performed under a heating ramp of 12 ºC/min and final temperature of 500 ºC. This treatment induced a strong decrease in the CCR, of about 70 %, and a slight increase in the content of water.
Taverna, Maria Eugenia (1,2); Polo, Mara Lis. (2); Zocola, Maria Evangelina (3); Bertero, Melisa ... more Taverna, Maria Eugenia (1,2); Polo, Mara Lis. (2); Zocola, Maria Evangelina (3); Bertero, Melisa (3) (1) UTN Regional San Francisco, Av. de la Universidad 501, (2400) San Francisco, Cordoba, Argentina. (2) INTEC (UNL-CONICET), Guemes 3450, (3000) Santa Fe, Argentina. (3) INCAPE (UNL– CONICET) Colectora Ruta Nac. No 168 Km 0 – Paraje El Pozo (3000) Santa Fe, Argentina.
Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Ci... more Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto de Investigaciones en Catalisis y Petroquimica ; Argentina
Sustainable Technologies for the Management of Agricultural Wastes, 2017
Palm kernel shell (PKS) and empty fruit bunches, both raw (EFB-R) and pretreated by means of auto... more Palm kernel shell (PKS) and empty fruit bunches, both raw (EFB-R) and pretreated by means of autoclaving (EFB-A) and microwave (EFB-M), were pyrolyzed in a fixed-bed stainless steel reactor at 550 °C. The yield of the water-soluble liquid fraction (pyroligneous acid, PA) in the pyrolysis of PKS was 26%wt. (dry basis) and in the range of 16–46%wt. when different EFB were used. The yield of insoluble liquid fraction (bio-oil, BO) was 9.1%wt. for PKS and up to 25%wt. in the case of EFB. Liquid and gaseous products were analyzed by conventional capillary gas chromatography. The PA from the PKS had 30%wt. of total phenolic compounds (up to 24%wt. phenol) and 46%wt. acetic acid. On the other hand, the bio-oil from PKS had 43%wt. of total phenolic compounds (up to 26%wt. phenol) and 17%wt. acetic acid. The PA from EFB contained mainly acetic acid (65.5%wt.), furfural (7.7%wt.), methanol (8.0%wt.), and phenol (15.2%wt.). When EFB was pretreated, the concentration of acetic acid in PA decreased dramatically, while the concentration of furfural increased up to ten times, this effect being more noticeable in the case of microwave pretreatment. The yields of by-products were of significance in all cases (13–23%wt. of gases and 33–52%wt. of char). These results show that the liquid products obtained from the pyrolysis of palm oil industrial wastes could be used in order to obtain chemical raw materials of worldwide extended use, while the by-products (gases and char) can be used as renewable energy sources.
The immediate catalytic conversions of pyrolytic bio-oils from pine sawdust and soybean shell ove... more The immediate catalytic conversions of pyrolytic bio-oils from pine sawdust and soybean shell over mesoporous catalysts (silica, alumina, and silica-alumina) and their combinations with Y zeolite, were studied. The effect of mesoporosity and acidity on the bio-oil deoxygenation and conversion into hydrocarbons was investigated. Pyrolysis and immediate catalytic conversion of bio-oil were performed in an integrated pyrolysis–upgrading reactor, for 7 min under a 30-ml/min flow of nitrogen at 550 °C. Important differences were observed in the conversion of the bio-oils, according to the composition of the raw biomasses. Pine sawdust bio-oil produced more coke and less hydrocarbons in the range of gasoline than soybean shell bio-oil over all the catalysts. Mesoporous catalysts showed conversion and deoxygenation between 14 and 29 percentage points higher with the more acidic solid (SiO2-Al2O3) in the case of pine sawdust bio-oil and between 2 and 10 percentage points higher with the solid having the highest specific surface area (SiO2) in the case of soybean shell bio-oil. Among the compound catalysts, the best performance for the case of pine sawdust corresponded to the catalyst with the highest mesoporosity (Y/SiO2), while for soybean shell corresponded to the most acidic catalysts (Y/Al2O3 and Y/SiO2-Al2O3). Soybean shell bio-oil showed more low molecular weight compounds (less than 130 g mol−1), which diffuse more easily in the zeolite channels, thus favoring conversion and deoxygenation mechanisms. On the contrary, for pine sawdust bio-oil, the surface area contributed by the mesopores in the matrix played a key role in pre-cracking bulky molecules.
Spartina argentinensis, Panicum prionitis, and Arundo donax are perennial grasses and Geoffroea d... more Spartina argentinensis, Panicum prionitis, and Arundo donax are perennial grasses and Geoffroea decorticans is a shrub, all of which grow under adverse conditions in the Litoral region in Argentina. The pyrolytic conversion of these biomasses was studied at 550 °C in a fixed bed reactor during 30 min under N 2 flow with a 20 °C min −1 heating ramp starting at room temperature. The main products were liquid, two phases (aqueous and oil) being observed with the aqueous phases being the most important in all the cases (yields from 29.2 to 45.7 wt%). The highest yield for an oil phase (18 wt%) was observed with the shrub and the yield of gases and chars were similar in all the cases. By means of sequential vacuum distillation I was possible to selectively separate water, methanol and acetic acid which were present in the aqueous phases, thus increasing the concentration of high value compounds such as ketones, phenols and furans in the residual fraction. The concentration of phenolic compounds in the residual fraction was 60% higher than the initial one in the aqueous phase. The oil phase mainly contained phenols, ketones and acids with high molecular weight. According to these results, these biomasses can be considered as a source of energy, fuels or chemicals, and it is possible to propose a methodology to upgrade the aqueous fractions in pyrolysis liquids.
Oxygenated model compounds representing typical components of bio-oils and a hydrocarbon hydrogen... more Oxygenated model compounds representing typical components of bio-oils and a hydrocarbon hydrogen donor agent were used to study hydrogen transfer reactions between hydrocarbons and oxygenated compounds when co-processed over acidic commercial FCC catalysts. Phenol, syringol, and trimethoxybenzene were each mixed with tetralin at 5 wt%. individually in benzene as an inert solvent. The mixtures were reacted in a fluidized bed, batch CREC Riser Simulator laboratory reactor during 10 s contact time with catalyst to oil relationship of 3 at 500 ºC over a commercial equilibrium FCC catalyst, conditions being selected in order to simulate FCC bio-oil-VGO co-processing. Tetralin was also reacted alone at 5 wt%. in benzene to gather background information. When tetralin was the only reactant, its conversion was 87 %, most important
Changes were produced by means of alkaline lixiviation in the porosity of an equilibrium commerci... more Changes were produced by means of alkaline lixiviation in the porosity of an equilibrium commercial FCC catalyst formulated to maximize the yield of middle distillates, in order to improve its performance in the conversion of tar from the pyrolysis of cow manure into hydrocarbons. The pyrolysis was produced at 650 °C in a fixed bed reactor and the tar was catalytically upgraded, comparing the performances of the parent and modified catalysts under realistic FCC conditions, in a CREC Riser Simulator reactor at 550 °C during 10 s, catalyst to reactant relationships being 3, 5 and 8. The alkaline treatment increased both acidity and average mesopore size of the commercial catalyst, thus favoring the diffusion process of the bulkiest oxygenated molecules in tar. The modified catalyst was more effective in deoxygenating tar (conversions up to 87.5% and deoxygenation up to 74.6%), producing more hydrocarbons and coke than the parent catalyst. According to the chemical nature of the pyrolitic tar from cow manure, a high proportion of paraffins derived from the primary cracking of its components were observed among the product hydrocarbons in the gasoline range over both catalysts.
A commercial equilibrium FCC catalyst of the octane-barrel type was subjected to lixiviation trea... more A commercial equilibrium FCC catalyst of the octane-barrel type was subjected to lixiviation treatments with both acidic (HNO 3) and basic (NaOH) solutions in order to modify its textural and acidic properties. The alkaline lixiviation doubled the mesopore volume in the commercial catalyst, while the acidic treatment increased the concentration of crystalline component in the catalyst. The catalytic performances of the parent and modified catalysts in the immediate conversion of vapors from pine sawdust fast pyrolysis were evaluated in a fixed bed reactor at 550 ºC using mass catalyst to biooil ratios from 3 to 8. The modified catalysts both produced more hydrocarbons and less coke than the parent commercial catalyst. In turn, comparing the modified samples, the one subjected to alkali treatment was more effective in deoxygenating the pyrolysis vapors, resulting in higher hydrocarbon yields (up to 13.2 %) and lower coke yields than the acid modified catalyst, a fact assigned to the higher mesoporosity which improves the diffusion transport of bulky coke precursor molecules. The acid modified catalyst allowed a higher extension of the reaction pathway, the selectivity to aromatic hydrocarbon products being much higher (up to 95.5 % of hydrocarbons in the gasoline boiling range).
Matrices of FCC catalysts with different content of alumina and the compound catalysts prepared w... more Matrices of FCC catalysts with different content of alumina and the compound catalysts prepared with them including Y zeolite were used to upgrade bio-oils from pine wood sawdust and soybean shell. The biomasses were selected according to their different lignin content which results in very different proportions of phenolic compounds (coke precursors) in the respective bio-oils. The bio-oils were produced by fast pyrolysis and the vapours were immediately upgraded over a fixed bed of catalyst at 550 °C using a mass catalyst/bio-oil relationship of 3.5. In terms of hydrocarbon yield, the matrices were more effective in deoxygenating pine wood sawdust bio-oil and the compound catalysts in deoxygenating soybean shell bio-oil. These differences can be the consequence of the different compositions of the bio-oils which, in the case of pine wood sawdust, includes a significant concentration of phenolic ethers which form coke on the matrix and the external surface of the zeolite, thus preventing lighter compounds from accessing the micropore system of the compound catalysts. Pine sawdust bio-oil produced more coke than soybean shell bio-oil; in the case of compound catalysts, coke deposited preferentially on the catalyst matrix, thus decreasing its mesopore specific surface area up to 65 %.
The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equil... more The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equilibrium FCC catalyst was studied in order to define its potential as a source for fuels and chemicals. The experiments of pyrolysis and immediate catalytic upgrading were performed at 550 °C during 7 min with different catalysts to oil relationships in an integrated fixed bed pyrolysis-conversion reactor. The results were compared under the same conditions against those from pine sawdust, which is a biomass source commonly used for the production of bio-oil. In the pyrolysis the pine sawdust produced more liquids (61.4%wt.) than the soybean shell (54.7%wt.). When the catalyst was presented, the yield of hydrocarbons increased, particularly in the case of soybean shell, which was four time higher than in the pyrolysis. The bio-oil from soybean shell produced less coke (between 3.1 and 4.3%wt.) in its immediate catalytic upgrading than that from pine sawdust (between 5 and 5.8%wt.), due to its lower content of phenolic and other high molecular weight compounds (three and five times less, respectively). Moreover, soybean shell showed a higher selectivity to hydrocarbons in the gasoline range, with more olefins and less aromatic than pine sawdust.
Recent Advances in Thermo-Chemical Conversion of Biomass, 2015
Coprocessing bio-oils with conventional hydrocarbon feedstocks in the Fluid Catalytic Cracking (F... more Coprocessing bio-oils with conventional hydrocarbon feedstocks in the Fluid Catalytic Cracking (FCC) process in refineries is an interesting option for the production of fuel and petrochemical raw materials. The previous upgrading of bio-oils with a thermal treatment allows decreasing the content of coke precursors and improving their processing characteristics. The coprocessing of crude and upgraded bio-oil with vacuum gas oil (VGO) was studied in a CREC Riser Simulator reactor under typical commercial FCC conditions. It was observed that the addition of oxygenated feedstock (e.g., up to 5 wt%) did not affect the product distribution significantly. Coke yields in coprocessing were even lower than in the conversion of VGO alone, due to the simultaneous addition of water.
Y zeolite was desilicated by means of alkaline treatments (NaOH 0.05, 0.10 and 0.20 M) during 15 ... more Y zeolite was desilicated by means of alkaline treatments (NaOH 0.05, 0.10 and 0.20 M) during 15 min to produce varying mesoporosity over it. Catalysts were made with a SiO 2 matrix and a binder. Pine sawdust bio-oil was produced by pyrolysis and immediately upgraded on a bed of the compound catalysts. The experiments were produced in a fixed bed reactor at 550 ºC using different catalyst to reactants relationships. The desilicated zeolites were more effective than the parent zeolite to deoxygenate bio-oil and produce more hydrocarbons, with higher selectivity to olefins (more than 35 %wt.) and lower selectivity to aromatics (less than 60 %wt.) in gasoline. The selectivity to C4and gasoline olefins increased if the mesoporosity was higher, and the coke formed was less condensed. These observations were the result of improvements in the diffusion of bulky molecules in bio-oils, such as phenolic ethers, increasing their conversion to hydrocarbons.
Reactivity and product distributions in the conversion of five different compounds representing t... more Reactivity and product distributions in the conversion of five different compounds representing typical species in bio-oils were studied over an equilibrium FCC catalyst at 500 °C during 60 s in a fixed bed reactor. Acetic acid, methyl acetate, furfural, 3-methyl-2-pentanone and 2-hidroxy-3-methylcyclopentenone were dissolved at 5% wt. in water. Thermal conversions were performed under the same conditions with inert SiC in the bed. The test compounds converted very differently, deoxygenation being produced by decarboxylation and dehydration. Furfural and 3-methyl-2-pentanone gave the highest yields of hydrocarbons, with high selectivity to light olefins and, when liquid (case of ketones), to aromatics. Methyl acetate gave the highest yield of oxygenated compounds. Coke yields were important (maximum 12.8% wt., 2-hidroxy-3-methylcyclopentenone). Thermal conversions were similar to the catalytic ones with acetic acid and methyl acetate, and much lower for the other reactants. Compared catalytic experiments, the thermal yields of hydrocarbons were much higher with acetic acid, and the yields of oxygenated higher with methyl acetate ester. Much less hydrocarbons were produced thermally with the other reactants. This information may be useful for predicting contributions if these compounds are to be co-processed in existing FCC units or upgraded over acidic catalysts.
Bio-oils from different residual biomass raw materials (pine wood, mesquite wood and wheat shell)... more Bio-oils from different residual biomass raw materials (pine wood, mesquite wood and wheat shell) were produced by means of conventional pyrolysis at a temperature of 550°C during 60 min. Bio-oils were separated from gases, tar and char, to show yields between about 30 wt.% and 45 wt.%, and fractionated into water-and ether-soluble fractions in order to know their compositions. Gas chromatography-mass spectrometry was used to identify compounds and complemented with elemental analysis and Conradson carbon residue (CCR), together with water content, density and pH assessments. The composition of the bio-oils varied according to the source biomass. Compounds were considered in eleven main groups: acids, esters, linear aldehydes and ketones, cyclic ketones, furans, alcohols and sugars, phenols, other oxygenated cyclic compounds, hydrocarbons, ethers and nitrogen compounds. The physicochemical properties of bio-oils suggested that it is necessary to upgrade them before co-processing in conventional refining units such as those of catalytic cracking of hydrocarbons. Thermal pre-treatments were conducted with the aim of reducing the CCR of the bio-oils, resulting in a significant average 70% reduction. The concentration of coke precursor phenolic compounds, mainly phenolic ethers, was reduced between 7% and 25%. Another important consequence was the increase in the effective hydrogen index of the mixture, suggesting higher processability in FCC.
Uploads
Papers by Melisa Bertero