Catalytic Pyrolysis Of Biomass Research Articles

Design optimization and scale-up characteristics of a double-helical ribbon reactor for biomass catalytic pyrolysis

Pyrolysis characteristics are closely related with the inner mixing performance of biomass and biochar particles in agitated biomass catalytic pyrolysis reactors. In this study, a novel double-helical ribbon reactor was designed for biomass catalytic pyrolysis. DEM (Discrete Element Model) simulations were performed to optimize the structure and operating conditions. Model calibration and validation experiments were firstly conducted. The effects of structural parameters and rotation speed on mixing performance were further explored. The results showed that the mixture homogeneity was closely related to the impeller outer diameter and rotation speed, while the mixing rate could be optimized by adjusting the inner diameter and pitch. The optimal operation condition showed adequate mixing in the axial and radial directions. Besides, the scale-up analysis demonstrated that similar mixing performance was presented at the same Froude number. Finally, the correlations of mixing characteristics provided a theoretical reference for industrial reactors design.

Catalytic pyrolysis of biomass with Ni/Fe-CaO-based catalysts for hydrogen-rich gas: DFT and experimental study

The H2-rich gas produced by biomass pyrolysis with Ni-based catalysts were studied by DFT, thermodynamic simulation, and pyrolysis experiment. The complex reaction between volatiles of biomass pyrolysis was clarified through DFT calculation. The results proved that the Ea of key reactions for H2 production on Ni-Fe/CaO surface were lower than that on NC, which facilitates to produce H2. The order of the Ea of the rate determining step on Ni-Fe/CaO surface is toluene cracking reaction < water-carbon reaction < Boudouard reaction < methane steam reforming reaction < methane dry reforming reaction < water gas shift reaction, indicating water gas shift reaction is the key control reaction. When the temperature is 650 ℃, Ni-Fe/CaO can effectively adsorb CO2 to break the thermodynamic equilibrium of the water gas shift reaction and promote the forward reaction to generate H2. Thermodynamic simulation and pyrolysis experiments determined that 650℃ and Ni-Fe/CaO are the most suitable reaction condition for H2 formation. Under this condition, the liquid yield of biomass pyrolysis decreased by 18.32% and the gas yield was increased by 26.27% compared to that of Ni /CaO. More importantly, the H2 yield was increased by 18.29% to 453.34 mL/g-biomass.

Hydrocarbon-Rich Bio-Oil Production from Catalytic Pyrolysis of Biomass over the Undervalued ZSM-11 Zeolites

Hydrocarbon-Rich Bio-Oil Production from Catalytic Pyrolysis of Biomass over the Undervalued ZSM-11 Zeolites

Experimental Study on Pyrolysis of Rice Straw Catalyzed by CaO/Al2O3-Phosphate Mixture

CaO and phosphates showed synergistic effects in the regulation of pyrolysis products in the pyrolysis of when they were directly mixed with camphor wood. The alkyl phenol yield increased during the pyrolysis process of corn straw fermentation residue directly mixed with KH2PO4 supported by γ-Al2O3. Rice stalks from agricultural crops are often disposed as waste. However, the potassium phosphate impregnated raw straw pyrolysis with CaO and Al2O3 has not been reported. This paper studied the synergistic effects of CaO or Al2O3 and three potassium phosphates (i.e., KH2PO4, K2HPO4·3H2O, and K3PO4·3H2O) in the rice straw pyrolysis through pyrolysis–gas chromatography-mass spectrometer (Py-GC/MS) experiments. The results showed that CaO/Al2O3 and potassium phosphates showed synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. and increased the contents of phenols, aldehydes, acids, and levoglucosan (LG) from most samples and increased those of ketones compared with those catalyzed by potassium phosphates alone. They were suitable for the production of ketone-rich and acid-low bio-oil, which is an important precursor for the preparation of power or jet fuel. The highest contents of ketones (HCK) reached 56.65% and 56.02% in the pyrolysis of K3PO4·3H2O impregnated rice straw with CaO or Al2O3, respectively. The lowest contents of acids and acetic acid (LCA) were nearly or equal to 0, respectively. HCK and LCA were respectively significantly higher and lower than the values reported in the literatures for biomass catalytic pyrolysis using CaO/Al2O3 and potassium phosphates alone or in combination. Dehydration reactions, etc. were further promoted under the co-catalysis of the two catalysts, and some phenols could be converted to benzene products, etc. For 50% K3PO4·3H2O impregnated sample, the yields of furans reduced sharply after CaO addition. For most impregnated samples except 50% K2HPO4·3H2O and 30% and 50% K3PO4·3H2O samples, the contents of total furans and furfural increased after Al2O3 addition.

Catalytic pyrolysis of biomass with char modified by cathode materials of spent lithium-ion batteries for tar reduction and syngas production

The char modified by the battery cathode material was studied for catalytic pyrolysis of rice husk (RH). Compared to the direct mixing, the addition of cathode material to char by the impregnation was more favorable to synthesize the lignin char catalyst (i.e. char 1) with hierarchical pore structure and larger specific surface area. The char 1 decreased the Ea of the RH pyrolysis from 79 kJ/mol to 66 kJ/mol. The char 1 decreased the yield of liquid product from 23.2% to 12.3% and increased the yield of gas product from 35.2% to 52.2%. The char 1 decreased the contents of acids from 20.6% to 3.6% and phenols (tar surrogates) from 29.4% to 8.0%. The increase of hydrocarbons and CO2 indicated that the char catalysts had high catalytic reactivity in converting the oxygenated components (e.g., sugars, furans, acids, phenols) into light hydrocarbons (e.g., alkanes, aromatics) and micro-molecular gases (e.g., CO2, H2).

Hydrogen-Rich Gas Production from Two-Stage Catalytic Pyrolysis of Pine Sawdust with Calcined Dolomite

The potential of catalytic pyrolysis of biomass for hydrogen and bio-oil production has drawn great attention due to the concern of clean energy utilization and decarbonization. In this paper, the catalytic pyrolysis of pine sawdust with calcined dolomite was carried out in a novel moving bed reactor with a two-stage screw feeder. The effects of pyrolysis temperature (700–900 °C) and catalytic temperature (500–800 °C) on pyrolysis performance were investigated in product distribution, gas composition, and gas properties. The results showed that with the temperature increased, pyrolysis gas yield increased, but the yield of solid and liquid products decreased. With the increase in temperature, the CO and H2 content increased significantly, while the CO2 and CH4 decreased correspondingly. The calcined dolomite can remove the tar by 44% and increased syngas yield by 52.9%. With the increasing catalytic temperature, the catalytic effect of calcined dolomite was also enhanced.

Catalytic Pyrolysis of Biomass with Thermal Treatment Products of Spent Lithium-Ion Batteries for the Upgrading of Bio-Oil and Syngas

Catalytic Pyrolysis of Biomass with Thermal Treatment Products of Spent Lithium-Ion Batteries for the Upgrading of Bio-Oil and Syngas

Catalytic Pyrolysis of Biomass with Sulfonated Carbon Catalyst to Produce Levoglucosenone

Catalytic Pyrolysis of Biomass with Sulfonated Carbon Catalyst to Produce Levoglucosenone

Progress in understanding the coking behavior of typical catalysts in the catalytic pyrolysis of biomass

Catalytic pyrolysis is a promising thermochemical method to upgrade the fuel property of bio-oil through the deoxygenation of volatiles obtained from the pyrolysis of biomass.

Regeneration of pristine HZSM-5 extrudates during the production of deeply deoxygenated bio-oil fromex situcatalytic fast pyrolysis of biomass in a bench-scale fluidised-bed reactor

Deeply deoxygenated bio-oil with ∼1 wt% oxygen is produced inex situcatalytic fast pyrolysis applying an unmodified HZSM-5 with good regeneration performance.

Ni-Cao Bifunctional Catalyst for Biomass Catalytic Pyrolysis to Produce Hydrogen-Rich Gas

Ni-Cao Bifunctional Catalyst for Biomass Catalytic Pyrolysis to Produce Hydrogen-Rich Gas

Experimental investigation of naphthenic biofuel surrogate combustion in a compression ignition engine

Biomass catalytic fast pyrolysis (CFP) integrated with hydrotreating (HT) produces advanced biofuels that could be used as bio-blendstocks to improve the properties of petroleum diesel fuels and enhance their combustion in compression ignition engines. The biofuels produced by CFP and HT are rich in naphthenes (cycloalkanes) that could improve cold-weather behavior and reduce the sooting propensity of blended diesel fuels. In this study, a surrogate fuel (SF1) that simulates a high-quality naphthenic bio-blendstock recovered from biomass CFP and HT was blended with research-grade No.2 diesel fuel (DF2) in different volume percentages and experimentally investigated in a single-cylinder Ricardo hydra diesel engine. Experiments were conducted by varying the fuel injection timings from the knock limit to the misfire limit at the same engine operating conditions for all of the SF1-DF2 blends (up to 40% by volume) and baseline No.2 diesel fuel. Engine output performance, combustion characteristics, and emissions including nitric oxides (NOx), carbon monoxide (CO), total hydrocarbon (THC), and particulate matter (PM) were measured and analyzed. Experimental results showed that the surrogate blended at 10% and 20% by volume could yield comparable (<5%) engine output performance to that of baseline diesel at optimized fuel injection timings. Larger blend percentages (>20% & ≤40%) also exhibited good combustion controllability over a range of injection timings while sustaining a moderate reduction (∼10–20%) in engine output performance compared to baseline diesel. Increasing surrogate fuel blend percentage resulted in higher CO, THC, and PM emissions as cetane number decreased and the combustion ignition delay increased. This correspondingly reduced and retarded the onset and magnitude of the heat release, increased the burn duration and reduced the peak cylinder pressures and temperatures during combustion also causing lower NOx emissions for all SF1 blends. Results from the detailed experimental study ultimately indicate that based on the present surrogate fuel formulation representing a low-oxygenated naphthenic bio-blendstock produced from the CFP/HT pathway, such biofuels have the potential to be a viable drop-in fuel for compression ignition engines at moderate blend ratios without compromising engine performance and impacting exhaust emissions.

Deactivation mechanism and regeneration effect of bi-metallic Fe-Ni/ZSM-5 catalyst during biomass catalytic pyrolysis

Catalyst deactivation by coke deposition is the main obstacle in the catalytic pyrolysis of biomass. In this study, catalytic pyrolysis of poplar sawdust has been performed in a fixed bed reactor and pyrolysis–gas chromatography/mass spectroscopy (Py-GC/MS) over fresh and regenerated bi-metallic Fe-Ni/ZSM-5 catalysts in order to evaluate the catalytic deactivation process and regeneration effects. The incorporation of Fe and Ni into ZSM-5 promoted deoxygenation activity and hydrocarbon yield. The deoxygenation activity of the catalyst gradually decreased with increasing cumulative biomass/catalyst ratio. At the cumulative biomass/catalyst ratio of 4, the catalyst appears to be completely deactivated, as evidenced by a decrease in the hydrocarbon yield. The coke resistance capacity of bi-metallic Fe-Ni/ZSM-5 was increased due to the stabilizing effect of the bi-metallic active sites. The regenerated catalyst retains deoxygenation activity during the catalytic pyrolysis process, although the aromatic yield (20.85%) was slightly lower than that of the fresh catalyst (21.52%). The physicochemical properties of regenerated catalysts showed that the partial irreversible loss of acidic sites and pore structure are responsible for the slightly reduced activity of the regenerated catalyst. These findings suggest that the bi-metallic Fe-Ni/ZSM-5 catalyst is a promising candidate for industrial application in the field of catalytic pyrolysis.

Effect of Fe/Cu catalysts supported on zeolite/active carbon hybrid on bio-oil quality derived from catalytic pyrolysis of granular bacteria biomass

Catalytic conversion of granular bacteria biomass to biofuel through pyrolysis was thoroughly studied. The hybrid of beta zeolite and active carbon (ZAC) resulted a support of catalyst with the BET surface area of 302 cm2/g. The highly active bimetallic Fe/Cu catalysts were prepared using wetness incipient impregnation on ZAC hybrid support (Fe5CuXZAC, X = 0.5, 1 and 2). To compare the activity of catalysts, catalytic pyrolysis tests of granular bacteria was performed. The pyrolysis tests in presence of Fe5Cu2ZAC remarkably decreased nitrogen compounds and total oxygenates of the bio-oil from 41.6 and 24.7 to 30.0 and 15.6 area%, respectively. Also, good selectivity of bimetallic Fe/Cu catalysts supported on ZAC toward aromatization reactions with the maximum yield for Fe5Cu2ZAC has made it a novel catalyst for pyrolytic conversion of granular bacteria biomass to aromatic hydrocarbons.The synthesized samples were characterized by Fourier transform infrared (FTIR) spectrometer, field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP), BET (Brunauer–Emmett–Teller) and temperature-programmed desorption (TPD) techniques. The products were analyzed by a gas chromatography-thermal conductivity detector (GC-TCD), a gas chromatography-mass spectrometry (GC–MS) and CHNS. Temperature-programmed oxidation (TPO) analysis was performed to study probable deposited carbon on the used catalysts.

Catalytic Pyrolysis of Lignin Model Compound (Ferulic Acid) over Alumina: Surface Complexes, Kinetics, and Mechanisms

Studies of the thermochemical properties of the important model compound of lignin-ferulic acid (FA) and its surface complexes are substantial for developing technologies for catalytic pyrolysis of renewable biomass into biofuels and lignin-derived chemicals as well as for bio-oil upgrading. In this work, the catalytic pyrolysis of ferulic acid over alumina was studied by temperature-programmed desorption mass spectrometry (TPD MS), in situ FT-IR spectroscopy, thermogravimetric analysis, and DFT calculations. We established that both the carboxyl group and the active groups (HO and CH3O) of the aromatic ring interact with the alumina surface. We calculated the kinetic parameters of formation of the main products of catalytic pyrolysis: 4-vinylguaiacol, guaiacol, hydroxybenzene, benzene, toluene, cresol, naphthalene, and PACs. Possible methods of their forming from the related surface complexes of FA are suggested.

Investigation of catalytic pyrolysis of Azolla filiculoides and Ulva fasciata for bio-oil production

The present study investigates the production of bio-oil by catalytic pyrolysis of macroalgae biomass. The effect of catalyst type and catalyst to feed ratio on the yield of bio-oil production and its qualitative characteristics were investigated. Experimental results showed that the maximum yield of the bio-oil production for Azolla and Ulva biomass were respectively 26.5% and 29.5%, both with HZSM-5 catalyst and with the catalyst to feed ratio of 1:10. The largest obtained higher heat values were 36.73 MJ/kg for Azolla bio-oil and 36.18 MJ/kg for Ulva bio-oil, both with 1:5 Mo/HZSM-5 catalyst. Regarding comparing Azolla and Ulva yield, Ulva bio-oil with efficiency, HHV, energy efficiency, cetane number, iodine value of 26.6%, 34.76 MJ/kg, 75.79%, 73.2, and 116.5, respectively. The results show that the bio-oil produced from the pyrolysis of Azolla and Ulva biomass can be very promising for industrial-scale production.

Selective catalytic synthesis of bio-based terephthalic acid from lignocellulose biomass

_Efficient synthesis of bio-based chemicals from renewable lignocellulosic biomass is of great significance to promote the sustainable development of chemical industry. This work aims to demonstrate that terephthalic acid, a bulk high value chemical in petrochemical industry, can be synthesized using biomass. This novel controllable transformation process was started with the selective catalytic pyrolysis of sawdust biomass to form p-xylene intermediate. The high p-xylene yield of 23.4% was obtained using the Ga2O3/SiO2/HZSM-5 catalyst under the optimized reaction condition. Subsequently, the selective oxidation of the biomass-derived aromatic intermediates to terephthalic acid was realized with the metal oxide catalysts. The highest terephthalic acid yield of 72.8% with the terephthalic acid selectivity of 82.3% was achieved using the CoMn2O4@SiO2@Fe3O4 catalyst. Based on the study of the catalytic conversion of the model compounds and the catalyst characterizations, the reaction pathways and possible reaction mechanism have been proposed.

Enhancing the Synergistic Effect of Cellulose and Polypropylene for Petrochemical Production during Catalytic Fast Pyrolysis by Mesoporous Gallium-MFI Zeolites

Co-feeding plastic waste has been considered to be an attractive method to enhance aromatic production and mitigate coke formation during catalytic fast pyrolysis (CFP) of lignocellulosic biomass with zeolite catalysts. However, insignificant synergistic effects for aromatic production have been observed for the cofeed CFP of cellulose and polypropylene (PP) during CFP with the conventional ZSM-5 zeolites. In this study, a series of mesoporous ZSM-5 and gallium (Ga)-containing MFI zeolites were prepared by desilication of conventional ZSM-5 zeolite with alkaline treatment (DS-ZSM-5) and hydrothermal synthesis of galloaluminosilicate with or without post-alkaline treatment (GaMFI and DS-GaMFI). These zeolites were then tested for the cofeed CFP of cellulose and PP mixture. The results indicate that the generation of mesopores in microporous MFI zeolite by alkaline treatment can alleviate the steric hindrance effect of PP-derived branched olefins on their catalytic conversion, while the incorporation of Ga can considerably increase the dehydrogenation activity of the zeolites, thus enhancing the transformation of alkanes and olefins to aromatics. Therefore, these zeolites considerably enhanced the synergistic effect of cellulose and PP for aromatic production during the cofeed CFP, compared to the conventional ZSM-5 zeolite. The aromatic yield increased markedly from 32.9 C% for ZSM-5 to 40.9 C%, 47.9 C%, and 52.7 C% for the DS-ZSM-5, GaMFI, and DS-GaMFI zeolites, respectively. Meanwhile, the formation of undesired coke was moderately mitigated during cofeed CFP with the DS-ZSM-5 and DS-GaMFI zeolites. The results of this study demonstrate that the DS-GaMFI zeolite can provide an effective catalyst to enhance aromatic production in the cofeed CFP of lignocellulosic biomass and plastics.

Catalytic pyrolysis of pine needle biomass over Fe–Co–K catalyst for H2-rich syngas production: Influence of catalyst preparation

In this work, the effects of preparation methods of Fe–Co–K catalysts on biomass pyrolysis were studied in a fixed bed reactor under 0.1 MPa N2 and 700 °C. The results showed that Fe–Co bimetallic catalyst has better activity than Fe. the yields of H2 and CO increased from 84.90 ml/g and 63.94 ml/g (Fe) to 98.42 ml/g and 85.43 ml/g (Fe + Co) prepared by co-impregnation, respectively, and the CO2 yield was 276.94 ml/g. The preparation of Fe∗ + Co∗ catalyst by co-precipitation could not only improve the yields of H2 (138.23 ml/g) and CO (89.75 ml/g), but also reduce the CO2 yield (225.19 ml/g). In the Fe∗ + Co∗ catalyst system, the addition of 0.6 wt% K increased the yields of H2 and CO to 153.85 ml/g and 107.80 ml/g. Characterization proved that the crystallinity of Co3Fe7 in Fe∗+Co∗ was stronger than that of Fe + Co, and the addition of Co facilitates the reduction of Fe, K promoted the dispersion of Fe∗ + Co∗ and enhanced the catalytic activity. This study provided theoretical support for increasing the yields of H2 and CO while reducing the CO2 yield.

A Review of Recent Research on Catalytic Biomass Pyrolysis and Low-Pressure Hydropyrolysis

Direct catalytic upgrading of biomass-derived fast pyrolysis vapors can occur in different process configurations, under either inert or hydrogen-containing atmospheres. This review summarizes the myriad of different catalysts studied and benchmarks their deoxygenation performance by also taking into account the resulting decrease in bio-oil yield compared to a thermal pyrolysis oil. Generally, catalyst modifications aim at improving the initial selectivity of the catalyst to more desirable oxygen-free hydrocarbons and/or improving the catalysts’ stability against deactivation by coking. Optimizing the pore structure and acid site density/distribution of solid acid catalysts can slow down deactivation and prolong activity. Basic catalysts such as MgO and Na2O/γ-Al2O3 are excellent ketonization catalysts favoring oxygen removal via decarboxylation, whereas solid acid catalysts such as zeolites primarily favor decarbonylation and dehydration. Basic catalysts can therefore produce bio-oils with higher H/C ratios. However, since their coke formation per surface area is higher, compared to a microporous HZSM-5 zeolite, precoking (or imperfect regeneration) of these basic catalysts and operating for longer time-on-stream can be approaches to improve the oil yield. In-line vapor-phase upgrading with a dual bed comprising a solid acid catalyst followed by a basic catalyst active in ketonization and aldol condensation further improves deoxygenation while maintaining high bio-oil carbon recovery. Also low-cost catalysts such as iron-rich red mud have deoxygenation activity. An improved bio-oil carbon recovery─compared at a similar level of oxygen removal─can be obtained when changing from an inert atmosphere to a hydrogen-containing atmosphere and using an effective hydrodeoxygenation (HDO) catalyst. To keep costs low, this can be conducted at near-atmospheric pressure conditions. Pt/TiO2 and MoO3/TiO2 showed high activity and reduced coke formation. Stable performance has been demonstrated using Pt/TiO2 for 100+ reaction/regeneration cycles with woody biomass feedstock. If future works can demonstrate the same durability for lower-cost biomass containing higher contents of ash, N, and S, this would considerably boost the commercial viability of near-atmospheric pressure HDO. Further research should be directed to testing the durability of lower-cost HDO catalysts such as MoO3/TiO2 and further improving the activity and stability of lower-cost catalysts.