Char Catalyst Research Articles

Effect of bone char catalyst on the pyrolysis behavior and crystal structure of cotton stalks

This study investigated the characteristics of bone char (BC) in the in situ catalytic pyrolysis of cotton stalk (CS) using a fixed-bed pyrolysis system at 600 °C. The results revealed that BC contained abundant pore structures and polar active sites, which prolonged the residence time of gases and provided numerous reaction sites for the secondary reaction of pyrolysis products. At a CS-to-BC mass ratio of 1:2 (CB-1:2), the reaction rate was accelerated. As the BC proportion increased, the crystallinity of the char decreased, while the specific surface area increased. At CB-1:2, both the crystallite size and crystallinity of BC improved. The oxygen-containing functional groups in BC, such as CO32−, PO43−, −COOH, and −OH, effectively increased the adsorption active sites. Additionally, Ca2+ in BC promoted dehydrogenation, deoxidation, fused cyclization, and decarboxylation of carboxylic acids, leading to increased production of H2, CO, and CO2. Moreover, Ca2+ facilitated the homolytic reactions of lignin, generating hydrogen free radicals. These radicals reacted with methoxy radicals formed during lignin decomposition to produce methane.

Study on the characteristics of microwave pyrolysis of pine wood catalyzed by bimetallic catalysts prepared with microwave-assisted hydrothermal char

Bimetallic hydrothermal char catalysts (Co-Ni/MHC, Fe-Co/MHC, Fe-Ni/MHC) were prepared through ionic hydrothermal methods and microwave high-temperature activation. During catalyst preparation, different metals synergistically promoted the formation of ordered carbon structures such as carbon nanotubes and carbon microspheres, respectively. Serving both as microwave absorbers and catalysts for the microwave pyrolysis of pine wood, the bimetallic catalysts exhibited distinct advantageous characteristics. Fe-Ni/MHC exhibited excellent microwave absorption properties and was able to assist the PW to heat up rapidly at a rate of 6.17 °C/s, benefiting from which PW achieved a high bio-oil yield of 44.0 % in the microwave-assisted catalytic pyrolysis process. Using Co-Ni/MHC as a catalyst resulted in bio-oil with up to 42.7 % styrene content and had good catalytic effects on the formation of CO and H2. This study provides a scientific reference for the application of hydrothermal treatment and microwave-assisted pyrolysis in biomass pyrolysis technology.

Catalytic pyrolysis of poplar sawdust over biochar of varied origin: Impact of volatile-char interactions

Volatile-char interaction is almost unavoidable in pyrolysis, which is part of the process shaping composition of bio-oil/gases and properties of char. In this study, the influence of the char from sawdust/spinach/rice/spirulina/pig manure on pyrolysis of poplar sawdust was investigated at 500 °C, aiming to understand the impact of the char of same or varied origin on formation of volatiles/gases and change of the char catalysts themselves from the volatile-char interaction. The results suggested that the sawdust-, spinach- or rice-char catalyzed cracking of volatiles, reducing formation of heavy tar, decreasing production of bio-oil (28.6–35.5 % vs 49.4%) while enhancing gases generation (36.9–44.0 % vs 22.4%). The spirulina- and manure-char enhanced secondary condensation of volatiles, producing more heavy tar, more bio-oil, and additional oxygen-rich carbonaceous deposit with highly aliphatic nature. This reduced thermal stability, the C/O ratio of the char catalyst, and also led to coverage of char surface, especially for the manure-char catalyst. The in-situ IR techniques showed that manure-char catalyzed formation of abundant ketones and esters/lactones in intermediates, which further involved in polymerization. In comparison, the sawdust-char catalyst catalyzed cracking and aromatization of the volatiles of same origin, producing carbon- and hydrogen-rich carbonaceous solid, enhancing aromatic nature of the char catalyst, which was actually a real process for evolution of structure of biochar in pyrolysis of the sawdust.

Catalytic conversion of volatiles over homologous char: Distinct interaction patterns at different temperatures

Char produced at specific pyrolysis temperatures has specific surface properties, which is also expected to have specific interaction patterns with volatiles produced at the same temperature. In this study, the char produced at varied temperatures was used for catalyzing conversion of homogenous volatiles generated at the same temperature. The aim was to explore the change of properties of char catalyst via volatiles-char interaction, which was almost equivalent to the evolution of property of char in pyrolysis. The results suggested that the char-300 (the number refers to temperature (°C) for production of char) and char-450 retained abundant oxygen-containing functionalities, rendering them superior activity for cracking of aliphatics and aromatics, producing less bio-oil with a lower abundance of π-conjugated structures but more gases (especially over char-450, increased by 57.8%). Char-600 and char-750, with a lower abundance of oxygen-containing functionalities, were not that active for cracking or interaction with volatiles, and their properties were also not changed that much. In comparison, the spent char-300 and char-450 experienced remarkable dehydrogenation and deoxygenation via interaction with volatiles, resulting in overall net weight loss, increased carbon content as well as enhanced thermal stability, aromatic degree, and carbon crystallinity. The biggest change of char-600 and char-750 could be the filling of pores with volatiles-derived deposits. The characterization of catalytic pyrolysis with in-situ IR technique also confirmed that the char-300 showed higher capability than char-750 for catalyzing conversion –OH and CO via varied reaction routes.

Evaluating the commercial potential of Cocos nucifera derived biochar catalyst in biodiesel synthesis from Kanuga oil: Optimization, kinetics, thermodynamics, and process cost analysis

In the current study, sulfonic acid functionalized steam-activated char catalyst was prepared from Cocos nucifera (coconut) husk (named as ACH-SO3H) at low temperatures for the pre-treatment of Kanuga oil to its methyl ester. This catalyst is attempted reportedly first time for Kanuga oil-derived biodiesel production. An ester yield of 99.51% was achieved over parametric states optimized by response surface methodology of catalyst loading 4.9 wt%, methanol concentration of wt%, for 83 min at 55.75 °C. Based on the proximate analysis, the feedstock Kanuga oil exhibited a high free fatty acid suggesting that the fuel production require the usage of an acid catalyst. Catalyst developed was examined using BET, SEM, EDAX, FTIR, and XRD. Fuel characterization of the produced methyl ester demonstrated that it has physico-chemical properties acceptable for biodiesel according to ASTM standards. The esterification reaction with ACH-SO3H exhibited kinetics that resembled pseudo-first-order behaviour, with an Ea of 68.83 kJ mol−1. Endothermic nature and non-spontaneity of the esterification reaction were confirmed through the thermodynamic study. Despite repeated use, the catalyst demonstrated outstanding stability, with the capacity to be reused thrice without notable decay in catalytic action. Catalyst production cost of $6.74/kg was estimated in the work.

Producing methane from dry municipal solid wastes: A complete roadmap and the influence of char catalyst

The lack of standardized products is a key hindrance to the widespread commercialization of municipal solid wastes (MSW) pyrolysis technology. In this paper, a cost-effective roadmap employing pyro-gasification and methanation processes is developed, with CH4-rich gas as the target product. In this roadmap, a two-stage catalytic conversion of “MSW → syngas → CH4-rich gas” was realized using MSW char, a by-product of the pyrolysis process as the catalyst/catalyst carrier. The results showed that, in the pyro-gasification stage, a syngas yield of 1.3 L/gMSW could be obtained at 800 °C and a steam-to-MSW mass ratio of 0.4, with a H2 fraction reaching 56.6 vol%. The effective conversion of MSW to syngas was attributed to the superior catalytic activity of the MSW char. By comparing the catalytic activity and structural characteristics of the chars produced from various waste components, it could be determined that the high catalytic activity of the char required both active minerals derived from contaminated plastics and residue, and an appropriate proportion of carbon matrix from the biomass components in MSW. The gasified MSW char (G-MSWC), co-produced with the syngas, served as a carrier for the subsequent methanation catalyst. Due to the activation effect of steam during the syngas production stage, the pore structure of G-MSWC was improved and its defect density also increased. Consequently, G-MSWC demonstrated enhanced Ni–C interaction, facilitating the methanation activity. The final product from the methanation stage achieved a CH4 concentration of 52.9 vol%, and a CH4 yield of 11.25 mol/kgMSW. The above findings demonstrate the feasibility of the complete roadmap from MSW to CH4 and provide valuable guidance for decentralized MSW management based on pyrolysis technology.

Hydrogen production and coke resistance characteristic during volatile reforming over Fe2O3–Ce2O3/sludge char catalyst

The development of sludge to green hydrogen is a win-win solution for alleviating the environmental pollution caused by sludge and low-carbon hydrogen production. A series of iron-cerium bimetallic oxide catalysts on sludge char (SC) were prepared for catalytic volatile reforming in this work. The physicochemical properties of the catalysts were adjusted by doping with different metals and changing the proportion. The results showed that 50Fe50Ce/SC possessing the minimum coke deposition rate (12.79 mg h−1·gcat−1) obtained a hydrogen yield of 280.55 ml g−1 from catalytic reforming at 800 °C with a steam-to-carbon ratio of 4:1. Analysis of the catalyst structure and activity suggested that the excellent activity mainly originated from the large number of oxygen vacancies. Oxygen vacancies promote the migration of lattice oxygen inside the catalyst bulk to the surface to react with the coke deposition, while the missing oxygen of the catalyst is replenished by steam, and oxygen vacancies play an important role in the enhancement of the catalyst activity and the elimination of coke deposition. The positive potential of this study in hydrogen production and carbon reduction were assessed. The study could provide new ideas for organic solid waste to generate green hydrogen and the development of efficient and low-cost catalysts.

Importance of oxygen-containing functionalities and pore structures of biochar in catalyzing pyrolysis of homologous poplar

Biochar and bio-oil are produced simultaneously in one pyrolysis process, and they inevitably contact and may interact, influencing the composition of bio-oil and modifying the structure of biochar. In this sense, biochar is an inherent catalyst for pyrolysis. In this study, in order to investigate the influence of functionalities and pore structures of biochar on its capability for catalyzing the conversion of homologous volatiles in bio-oil, three char catalysts (600C, 800C, and 800AC) produced via pyrolysis of poplar wood at 600 or 800 °C or activated at 800 °C, were used for catalyzing pyrolysis of homologous poplar wood at 600 °C, respectively. The results indicated that the 600C catalyst was more active than 800C and 800AC for catalyzing cracking of volatiles to form more gas (yield increase by 40.2%) and aromatization of volatiles to form more light or heavy phenolics, due to its abundant oxygen-containing functionalities acting as active sites. The developed pores of the 800AC showed no such catalytic effect but could trap some volatiles and allow their further conversion via sufficient aromatization. Nevertheless, the interaction with the volatiles consumed oxygen on 600C (decrease by 50%), enhancing the aromatic degree and increasing thermal stability. The dominance of deposition of carbonaceous material of a very aromatic nature over 800C and 800AC resulted in net weight gain and blocked micropores but formed additional macropores. The in situ diffuse reflectance infrared Fourier transform spectroscopy characterization of the catalytic pyrolysis indicated superior activity of 600C for removal of –OH, while conversion of the intermediates bearing CO was enhanced over all the char catalysts.

Cobalt-supported activated biochar in the co-pyrolysis of cattle manure and rice husk

It is crucial to develop an efficient catalyst for catalytic co-pyrolysis. In this paper, the catalytic co-pyrolysis of cattle manure and rice husk over a catalyst loaded with cobalt (Co) using potassium hydroxide-activated biochar as the support was conducted in a two-stage fixed-bed reactor. The results showed that the cobalt/potassium rice husk char (KRHC) catalyst displayed a good catalytic pyrolysis process with a large specific surface area and a developed pore structure. Loading with cobalt not only improved the quality of syngas but also increased syngas yield. Hydrogen content increased from 4.55 to 13.68% and carbon monoxide content increased from 19.78 to 32.25%, whereas carbon dioxide content decreased from 7.32 to 5.3% and methane content decreased from 8.01 to 6.07%. Syngas yield increased from 3.68 to 4.58 N m3/kg. The catalyst promoted the breaking of C–C and C–O bonds in tar, increased the content of phenols, ketones and aldehydes, and reduced the content of oxygen in the syngas. The catalysts also maintained good performance after five catalytic cycles, with hydrogen and carbon monoxide contents of approximately 10 and 27.5%, respectively.

Interaction of the lignin-/cellulose-derived char with volatiles of varied origin: Part of the process for evolution of products in pyrolysis

The interaction between volatiles and homologous and/or heterologous char is almost inevitable during the transfer or diffusion of volatiles from inner core to outer surface of a biomass particle in pyrolysis. This shapes both composition of volatiles (bio-oil) and property of char. In this study, the potential interaction of lignin- and cellulose-derived volatiles with char of varied origin was investigated at 500 °C. The results indicated that both the lignin- and cellulose-char promoted polymerization of the lignin-derived phenolics, enhancing production of bio-oil by ca. 20%–30%, generating more heavy tar but suppressing gases formation, especially over cellulose-char. Conversely, the char catalysts, especially the heterologous lignin-char, promoted cracking of the cellulose-derivatives, producing more gases while less bio-oil and heavy organics. Additionally, the volatiles-char interaction also led to gasification of some organics and also aromatization of some organics on surface of char, resulting in enhanced crystallinity and thermostability of the used char catalyst, especially for the lignin-char. Moreover, the substance exchange and formation of carbon deposit also blocked pores and formed fragmented surface dotted with particulate matters in the used char catalysts.

Pyrolysis-catalytic steam reforming of waste plastics for enhanced hydrogen/syngas yield using sacrificial tire pyrolysis char catalyst

Pyrolysis-catalytic steam reforming of waste plastics to produce hydrogen-rich syngas has been investigated using tire char as a sacrificial catalyst in a two-stage pyrolysis-catalytic steam reforming reactor system. The simultaneous steam reforming of the pyrolysis volatiles and ‘sacrificial’ steam gasification of tire char increased the overall yield of syngas and hydrogen in the gas products. Manipulating the catalyst temperature, steam input, char catalyst:plastic ratio influenced hydrogen yield. The presence of metals such as Zn, Fe, Ca and Mg in tire char, play a catalytic role in steam reforming reactions. The syngas production achieved when the catalyst temperature was 1000 °C and steam weight hourly space velocity was 8 g h−1 g−1catalyst was 135 mmol H2 g-1plastic and 92 mmol CO g-1plastic. However, increasing the amount of char catalyst (4:1 char catalyst:plastic ratio) enabled hydrogen yields of 211 mmol g-1plastic and total syngas yields of 360 mmol g-1plastic to be achieved.

Hydrogen/Syngas Production from Different Types of Waste Plastics Using a Sacrificial Tire Char Catalyst via Pyrolysis–Catalytic Steam Reforming

Hydrogen/Syngas Production from Different Types of Waste Plastics Using a Sacrificial Tire Char Catalyst via Pyrolysis–Catalytic Steam Reforming

Assessment of the inherent CaO in char on tar catalytic conversion by a micro fluidized bed reaction analyzer for biomass gasification

In this study, a newly-developed micro fluidized bed reaction analyser (MFBRA) was adopted to examine the effects of char’s inherent CaO on tar catalytic cracking from 1023 K to 1173 K. A simulated CaO-based char catalyst was prepared by impregnation method. For comparison, the blank experiments were also conducted by employing the demineralized char free of CaO. The tar cracking behaviour and reaction kinetics based on the gas products generation were systematically compared. The structure and reaction activity of char sample before and after experiment were also analyzed. The results shows that tar conversion processes can be divided into a fast cracking stage and a stable conversion stage. By increasing the reaction temperature, the tar conversion by char without CaO to the total gas products and its reaction rate changed from 41.15 % to 71.50 % and from 0.055 s−1 to 0.081 s−1, respectively; but for char with CaO, they improved from 57.54 % to 88.25 % and from 0.062 s−1 to 0.096 s−1, respectively. The presence of CaO dramatically enhanced tar conversion even at a low temperature of 1023 K, producing more effective gas components, such as H2, CO, CO2, and C2H6. For CH4 and C3H6, the promotion became obvious at high temperatures above 1123 K. During tar catalytic cracking, CaO suppressed carbon deposition on char surface to some extent. Meanwhile, the generation activation energy (Ea) of CH4, the total gas products, H2, CO2, CO, C2H6, and C3H6 decreased to a great extent, indicating the good catalytic activity of the inherent CaO in char.

Structural properties and reactivity variations of wheat straw char catalysts in volatile reforming

Abstract In this study, wheat straw char was prepared at 500°C and used as a catalyst (at 500–700°C) to reform the wheat straw volatiles. The char samples before and after reforming were characterized in terms of N2 adsorption (BET area), Raman spectroscopy, Fourier transform infrared spectroscopy, proximate analysis, ultimate analysis, and inductively coupled plasma measurements. The surface morphology of the used char was analyzed by a scanning electron microscope. The results have revealed that following the reforming process, the carbon content increased from 69.2% to 71.7% (at 500°C), 73.9% (at 600°C), and 74.3% (at 700°C) and the fixed carbon content increased from 64.6% to 68.7% (at 500°C), 71.4% (at 600°C), and 72.4% (at 700°C). In contrast, the higher heating value of the used char remained unchanged. We observed a decrease in specific surface area (from 112.67 to 7.93 m2·g−1), but an increase in char defects and functional groups following the reforming process (at 600°C) served to maintain catalytic activity, as shown in a second reforming test. Our results suggest that surface defects and functional groups are the main factors contributing to char reactivity.

Mitigation of hazardous toluene via ozone-catalyzed oxidation using MnOx/Sawdust biochar catalyst

This study investigated catalytic ozone oxidation using a sawdust char (SDW) catalyst to remove hazardous toluene emitted from the chemical industry. The catalyst properties were analyzed by proximate, ultimate, nitrogen adsorption-desorption isotherms, Fourier-transform infrared, and X-ray photoelectron spectroscopy analyses. In addition, hydrogen-temperature programmed reduction experiments were conducted to analyze the catalyst properties. The specific area and formation of micropores of SDC were improved by applying KOH treatment. MnOx/SDC-K3 exhibited a higher toluene removal efficiency of 89.7% after 100 min than MnOx supported on activated carbon (MnOx/AC) with a removal efficiency of 6.6%. The higher (Oads (adsorbed oxygen)+Ov(vacancy oxygen))/OL (lattice oxygen) and Mn3+/Mn4+ ratios of MnOx/SDC-K3 than those of MnOx/AC seemed to be important for the catalytic oxidation of toluene.

Characterizations of Ni-loaded lignite char catalysts and their performance enhancements to catalytic steam gasification of coal

Catalyst characteristics such as specific surface area, porosity and active site play an essential role in catalyst design. Understanding of the characteristic functions in controlling catalyst activity is necessary for considering the catalyst application, especially the Ni-loaded lignite char catalyst, employed in catalytic steam gasification. In this work, the unmodified and five modified catalysts were used to study the effect of catalyst characteristics on their performance for catalytic steam gasification of coal in the two-stage fixed-bed reactor. The findings indicated that the fresh acid modified catalysts increased specific surface area and micropore formation, including the smaller Ni metal crystallite size, the decreasing of Ni metal nanoparticle size and the well-dispersed of Ni metal nanoparticles. Meanwhile, the fresh modified catalysts by the alkali and the combined alkali-acid treatments promoted mesopore formation. Enhancing catalytic steam gasification of coal, it was found that the mesoporosity of catalyst was the considerable initial characteristic for controlling the catalyst activity. The total gas yields of the mesoporous catalysts were in the range of 50.65–77.70 mmol/gVM,feed, while the total gas yields of the microporous catalysts were 43.82–55.34 mmol/gVM,feed. After catalyst testings, the specific surface areas and number of mesopores in the spent catalysts were increased by steam. Remarkably, these changing pore sizes affected the transformations of the isotherms (type I + II to type II) and the hysteresis loops (type H4 to type H3). Also, steam influenced the conversion of Ni metals to NiO, Ni(OH)2 and Ni2O3. For thermal property, all spent catalysts had high thermal stability. The modified catalysts could decrease carbon deposition more than the unmodified catalyst, which was an upside for catalyst reusability.

Catalytic pyrolysis of cellulose with biochar modified by Ni–Co–Mn cathode material recovered from spent lithium-ion battery

In this study, we investigated the recycling of Ni–Co–Mn cathode materials from spent LIBs by an acid leaching process using H3PO4 and HCl. The leaching liquor was then used to modify the biochar applied during the catalytic pyrolysis of the biomass. The addition of char catalysts decreased the maximum decomposition rate and shifted it to a lower temperature. Accordingly, the activation energy (Ea) of cellulose pyrolysis decreased from 140.86 kJ/mol to 83.55 kJ/mol (char-P) and 89.42 kJ/mol (char-Cl). The char catalysts enhanced the transformation of the large-molecule components to small-molecule gases during cellulose pyrolysis. The addition of both char-P and char-Cl decreased the anhydrosugar content and increased the hydrocarbon content, suggesting their high catalytic activities in converting anhydrosugars to hydrocarbons (e.g., long-chain alkanes). The anhydrosugar content decreased from 17.8% to 11.1%, while the furan content increased from 5.1% to 15.2% with the addition of char-P. The addition of char-Cl resulted in a lower content of furans (4.8%) and a higher content of hydrocarbons (40.1%), mostly because of the increase in alkanes and aromatic compounds. Therefore, these char catalysts could be used for biomass pyrolysis in terms of activation energy reduction and upgrading the quality of the product. This win-win pyrolysis process is a promising pathway for the co-valorization of the cathode materials of spent LIBs and biomass waste.

Wet oxidation of thermochemical aqueous effluent utilizing char catalysts in microreactors

Production of bio-oil or biocrude from thermochemical processes such as pyrolysis and hydrothermal liquefaction (HTL) respectively, is considered a promising path for the production of alternative fuels and chemicals. However, these technologies create an aqueous phase byproduct contaminated with high concentrations of organic compounds. Traditional wastewater technologies rely on biological processing which is not resistant to the toxic levels of organic compounds present. Wet oxidation of aqueous phase byproducts is a promising processing alternative for such a dilute stream and a potential production pathway for value-added products such as acetic acid. Wet oxidation was carried out at near ambient temperature (75–90 °C) and atmospheric pressure in the presence of a hydrogen peroxide oxidant and a char catalyst activator on three individual aqueous phases. The three aqueous phases were thoroughly analyzed by total organic carbon (TOC), chemical oxygen demand (COD), Total Phenol, Total Acid Number, and individual constituents via gas chromatography with mass spectroscopy (GCMS). HTL aqueous phases were quite similar in every regard as can be seen by their COD of 44.8 and 41.5 g O2/L respectively. The pyrolysis aqueous phase was much more complex in nature with a 10X higher COD of 364.5 g O2/L. This was validated by ICRMS analysis which revealed the more complex molecules not visible by regular mass spectrometry. All the tests were conducted with a cellulose-based char catalyst doped with Nitrogen and Iron Oxide. The experiments were carried out in a microscale-based continuous reactor due to its superior continuous performance and reduction of transport limitations. Oxidation to small molecular weight compounds such as acetic acid was achieved with final products containing between 0.555 and 5.04 mg acetic acid/g liquid effluents. Our results confirm that wet oxidation is a promising process for the processing of aqueous effluents from biomass thermochemical conversion processes.

Biodiesel Synthesis from High Free-Fatty-Acid Chicken Fat using a Scrap-Tire Derived Solid Acid Catalyst and KOH.

A heterogeneous solid acid catalyst was synthesized using tire polymer waste (TPW) for the esterification of waste chicken fat (CF) enriched with fatty acids. The TPW was carbonized and functionalized with concentrated sulfuric acid under various sulfonation conditions to obtain a sulfonated tire polymer char (TPC-SO3H) catalyst. The TPC-SO3H catalyst was further characterized via acid-base titration (to ascertain the total concentration of acid), X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), and Brunauer–Emmett–Teller (BET) analysis. The esterification reaction conditions of extracted chicken fat with methanol and the viability of catalyst reuse were also investigated. The composition of the free fatty acid (FFA) decreased to below 1% under optimum reaction conditions of 5% TPC-SO3H catalyst, the methanol-to-CF molar-ratio of 15:1, and a reaction time of 120 min at 70 °C. The catalyst preserved its conversion efficiency above 90%, even after three cycles. The results demonstrate that the catalyst is applicable and efficient in the esterification of raw materials containing various fatty acid compositions since different carbonized materials have distinct abilities to combine acid groups. Furthermore, after de-acidification of CF-FFA by the as-prepared TPC-SO3H catalyst, the neutral CF was transesterified completely to biodiesel and characterized via Fourier Transform Infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy and physicochemical analysis. This work unveils a promising technique for utilizing tire waste generated in large quantities for the development of a novel heterogeneous acid catalyst for biodiesel production.

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).