Catalytic Pyrolysis Of Biomass Research Articles

Catalytic Fast Pyrolysis of Biomass over Hierarchical Zeolites: Comparison of Mordenite, Beta, and ZSM-5

Catalytic Fast Pyrolysis of Biomass over Hierarchical Zeolites: Comparison of Mordenite, Beta, and ZSM-5

Closing the loop: Biochar-supported nickel catalyst for efficient hydrogen-rich syngas production

Thermochemical conversion of agricultural by-products into hydrogen-rich syngas is a technology that offers both economic and environmental benefits. In this work, we investigated a biochar-supported nickel-based catalyst for the catalytic pyrolysis of straw biomass to produce hydrogen-rich syngas. The by-product, straw biochar, was used as a material for synthesizing fresh catalysts, achieving a closed-loop process. We explored gas yields under various conditions. The highest yields of CO and H2, reaching 0.52 L/g and 0.48 L/g, respectively, were obtained under the conditions of a pyrolysis temperature of 900 °C, a residence time of 20 min, a calcination temperature of 400 °C, a nickel loading of 15 wt%, and a citric acid to potassium hydroxide ratio of 1:4. The catalysts were characterized using XRD, H2-TPR, SEM, and TEM. The results demonstrated that biochar provides excellent support and synergy, enabling the catalyst to function at high temperatures and offering antioxidative protection to the active metals during the thermal process. Overall, this catalytic pyrolysis process, aiming for green and efficient conversion, achieved high yields of syngas and hydrogen.

Biomass Valorization through Catalytic Pyrolysis Using Metal-Impregnated Natural Zeolites: From Waste to Resources.

Catalytic biomass pyrolysis is one of the most promising routes for obtaining bio-sustainable products that replace petroleum derivatives. This study evaluates the production of aromatic compounds (benzene, toluene, and xylene (BTX)) from the catalytic pyrolysis of lignocellulosic biomass (Pinus radiata (PR) and Eucalyptus globulus (EG)). Chilean natural zeolite (NZ) was used as a catalyst for pyrolysis reactions, which was modified by double ion exchange (H2NZ) and transition metals impregnation (Cu5H2NZ and Ni5H2NZ). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), ammonium programmed desorption (TPD-NH3), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) allowed us to study the influence of natural and modified zeolite catalysts on BTX production. XRD analysis confirmed the presence of metal oxides (CuO and NiO) in the zeolite framework, and SEM-EDS confirmed successful metal impregnation (6.20% for Cu5H2NZ and 6.97% for Ni5H2NZ). Py-GC/MS revealed a reduction in oxygenated compounds such as esters, ketones, and phenols, along with an increase in aromatic compounds in PR from 2.92% w/w (without catalyst) to 20.89% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/5, and in EG from 2.69% w/w (without catalyst) to 30.53% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/2.5. These increases can be attributed to acidic sites within the catalyst pores or on their surface, facilitating deoxygenation reactions such as dehydration, decarboxylation, decarbonylation, aldol condensation, and aromatization. Overall, this study demonstrated that the catalytic biomass pyrolysis process using Chilean natural zeolite modified with double ion exchange and impregnated with transition metals (Cu and Ni) could be highly advantageous for achieving significant conversion of oxygenated compounds into hydrocarbons and, consequently, improving the quality of the condensed pyrolysis vapors.

Synthesis of HZSM-5@activated carbon for improving aromatic production from catalytic pyrolysis of biomass

HZSM-5 widely used for the catalytic pyrolysis of biomass exhibits the drawbacks of high diffusion resistance and large coke production. To effectively enhance the catalytic efficiency and alleviate the coke deposition, a novel promising catalyst, HZSM-5 coated activated carbon (HZSM-5@AC), was prepared for the first time for in-line upgrading the pyrolysis products of soybean straw. Various catalysts including HZSM-5, activated carbon, and the HZSM-5@AC catalysts with different HZSM-5 to activated carbon mass ratios were characterized. The results showed that the HZSM-5 was successfully coated on the surface of activated carbon and the addition of activated carbon introduced a mesoporous structure and more acidic sites to the catalyst. The catalytic performance on the biomass conversion showed that the catalyst with HZSM-5-to-activated carbon mass ratio of 18:5 (18HZSM-5@5AC) had the highest catalytic efficiency on the conversion of biomass into aromatics with a selectivity of 99.5%, including 75.68% of benzene, toluene, and xylenes (BTX) with a yield of 74.68 mg/g. Moreover, a possible pathway for HZSM-5@AC catalyzed biomass pyrolysis was proposed through analyzing the conversion of model compounds. The catalyst cycling experiments demonstrated the higher stability of HZSM-5@AC than the parent HZSM-5 and activated carbon. TG, FTIR, Raman and SEM showed that the spent HZSM-5@AC was hardly structurally changed with a low coke yield of 0.08%. However, the spent HZSM-5 was partly structurally deactivated by large aromatic ring systems with a coke yield of 3.74%. SEM results also showed that a large amount of polymerized material encapsulated the surface of the spent HZSM-5.

Promoted production of aromatic hydrocarbons in biomass catalytic pyrolysis over the coupled catalysts of carbon-reduced waste lithium battery cathode materials and HZSM-5

Inexpensive catalyst sources are of great importance in the conversion of biomass to economically valuable monocyclic aromatic hydrocarbons, and transition metals (Co, Ni, Fe and Mn) rich in catalytic effects in massive waste lithium battery cathode materials are not effectively reutilized currently. For this reason, the feasibility of employing the valuable metal oxides in the carbon-reduced waste lithium battery cathode materials (waste LiFePO4 batteries, LFP, and waste LiNixCoyMn1–x–yO2 batteries, NCM) with HZSM-5 as coupled catalysts in the rape straw catalytic pyrolysis to produce aromatic hydrocarbons was explored. The carbon-reduced waste lithium battery cathode materials performed well at 5 wt% carbon loading, and the content of active components Fe2O3 (SLFPC-5) and NiO (SNCMC-5) used for the reduction of large molecular oxygenates in biomass pyrolysis gas was increased by water leaching treatment. SLFPC-5 demonstrated superior bond-cutting performance, while SNCMC-5 exhibited strong deoxygenation performance. The selectivity of monocyclic aromatic hydrocarbons (MAHs) catalyzed by SLFPC-5/HZSM-5 and SNCMC-5/HZSM-5 was as high as 63.69 % and 79.19 %, with BTX yields of 14.58 wt% and 16.68 wt% respectively. This coupled catalytic system offers a low-cost source of catalysts for biomass catalytic pyrolysis and broadens the possibility of high-value recycling of wasted lithium batteries.

Catalytic pyrolysis of corncob residues and pubescens over pristine and alkalis-treated HZSM-5

The catalytic pyrolysis of corncob residues and pubescens was carried out using HZSM-5 and alkalis-treated HZSM-5 as catalysts. HZSM-5 treated with different alkalis (TPAOH and a mixture of NaOH and Na2CO3) to get TPHZSM-5 and DHZSM-5. It was shown that the acid sites of the DHZSM-5 and TPHZSM-5 catalyst decreased compared to pristine HZSM-5. The hierarchical structures combining micro- and meso- porosity was formed in DHZSM-5, which was more conducive to promoting the formation of mono-phenols. However, the pore size of the catalyst decreased and the strength strong acid site increased with TPAOH treatment, which was beneficial for promoting C-O bond cleavage and generating more monocyclic aromatic hydrocarbons (MAHs). Under the same conditions, HZSM-5 was most beneficial for improving the yield of bio-oil (45.9 wt% of corncob residues and 52.0 wt% of pubescens). Analysis of the bio-oil showed that the catalytic pyrolysis of biomass over HZSM-5 achieved the highest PAHs yield (31.45 % from corncob residues and 18.38 % from pubescens), while TPHZSM-5 obtained the highest MAHs yield (5.92 % from corncob residues and 2.03 % from pubescens). However, DHZSM-5 catalyst appeared to have no significant effect on the increase of MAHs and PAHs yield, which may be attributed to its promotion of secondary polymerization of pyrolysis products. Additionally, the catalyst promoted the secondary cracking of pyrolysis vapor and reduced the average molecular weight (Mn) of the bio-oil. DHZSM-5 and TPHZSM-5 catalysts offered significant potential for the valorization of lignin, facilitating the production of value-added mono-phenolic compounds, MAHs, and high-quality fuels.

Biogenically synthesized aluminum oxide nanoparticles via phyllanthus emblica seeds for photocatalytic applications

In this study, Phyllanthus emblica (amla) seed extract was employed to biosynthesize Aluminum oxide nanoparticles (Al2O3 NPs) as efficient stabilizers and bio-reducing agents. The successful synthesis of Al2O3 NPs was confirmed and characterized by UV–Vis spectroscopy (UV/Vis), Fourier Transform Infrared Spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD). Antibacterial activity of these environmental friendly Al2O3 NPs was evaluated through a disk diffusion method, demonstrating their potential as antimicrobial agents against pathogens, including gram-positive and gram-negative bacteria. Additionally, Al2O3 NPs exhibited substantial photocatalytic activity, achieving a remarkable 95.06% degradation of 4-nitroaniline (4-NA) under UV light irradiation. Furthermore, Al2O3 NPs served as efficient catalysts in catalytic biomass pyrolysis, boosting bio-oil yields by 47.4%. The resulting bio-oil was analyzed using FT-IR spectroscopy. This research emphasizes the significance of biomass waste in producing biofuel as well as disinfection and environmental remediation applications, offering sustainable solutions for various challenges.

Catalytic pyrolysis of wood dust for monophenol over macroalgal biochar-based catalyst: Effects of activation agents and atmospheres during catalyst synthesis on its performance

After introducing heteroatoms into the carbon material skeleton, the performance of carbocatalyst during catalytic pyrolysis of biomass for monophenol production is significantly improved. Algae, as a carbon source with intrinsic nitrogen content, is well-identified as a suitable raw material for preparing heteroatom-doped carbocatalyst. The present study aimed to investigate the effects of different alkaline activation agents (KOH/NaOH) and gas atmospheres (N2/CO2) during the carbonization-activation synthesis process of macroalgal biochar-based catalysts (MBBCs) on their properties and performances. Characterizations of carbocatalysts were carried out via BET and XPS analyses to investigate the porous structures and surface functional groups. Results showed that CO2, as a weakly oxidizing atmosphere, can promote the formation of porous structure of MBBCs. However, the promotion is not as strong as that of chemical activation agents (KOH/NaOH). Furthermore, KOH can promote the formation of porous structure more strongly than NaOH, but NaOH can substantially enhance the formation of surface oxygen‑nitrogen groups compared to KOH. All the MBBCs exhibited the increment of monophenols in the bio-oil obtained from catalytic pyrolysis of wood dust, especially phenol, o-cresol, and p-cresol. Amongst, the biochar-based catalyst activated with NaOH in CO2 atmosphere was the most effective one in promoting monophenols content (up to 59.46 %). Compared with the control group (without catalyst), the phenol content was increased from 5.03 % to 19.40 %. Moreover, it is found that the catalytic performance was positively correlated with the CO species percentage on the surface of MBBCs. The macroalgal biochar-based catalyst has an excellent catalytic performance, which is of great significance for achieving the complete utilization of algae and thereby improving the quality of catalytic pyrolysis products.

Production of monocyclic aromatic hydrocarbons by the catalytic pyrolysis of Moso bamboo at different ages and parts using Zn and Cr modified zeolite catalysts

Monocyclic aromatic hydrocarbons (MAHs) are important organic building blocks for the chemical industry, which can be produced by catalytic pyrolysis of biomass. The wide application of bamboo in Chinese industry generates a large amount of bamboo waste which can be utilized as the feedstock to produce MAHs. This study aimed to investigate the effect of bamboo age and bamboo part on the yield of the aromatics by using the Cr and Zn modified HZSM-5 as catalyst. The result showed that the incorporation of metals (Cr and Zn) enhanced the catalytic performance, and the incorporation of Zn was better than Cr. The highest MAHs content (38.67%) and total aromatic content (57.42%) were obtained with the catalyst of 3% Zn/HZSM-5 catalyst at temperature of 400 °C and duration time of 30 min. Younger age (1-year-old bamboo) and the outer skin of bamboo was better for the production of MAHs. This study provided a high value-added application approach for the waste Moso bamboo.

Coke formation on different metal-modified (Co, Mo and Zr) ZSM-5 in the catalytic pyrolysis of cellulose to light aromatics

Catalytic pyrolysis of biomass is regarded as a promising method for preparing value-added products. However, the main factors limiting the development of the process at present are the low yield of value-added products and poor selectivity, especially for rapid catalyst deactivation due to coke deposition. The present study focuses on the catalytic pyrolysis of cellulose over metal Co-, Mo-, and Zr-loaded catalysts using a falling fixed bed at 600 °C to evaluate the type of coking of the catalysts as well as the effect of the different metal active sites on the formation of coke deposits. The introduction of Co and Mo metal sites increased the light aromatics yield of ZSM-5 from 128.9 mg/g to 147.2 mg/g and 143.0 mg/g. And the yield of coke deposits decreased from 8.3 to 6.8 and 5.1 wt%. The stability evaluation of the catalyst showed that the deactivation degree of ZSM-5 of the supported metal Co was lower than that of commercial ZSM-5, while the ZSM-5 of the supported metal Mo was rapidly deactivated. The deactivation of the catalysts depended more on the morphology or location of the accumulated coke than on the total amount deposited. The clogging of metal and acidic sites on the surface of the zeolite and the pore channels by the amorphous encapsulating coke was the main cause of catalyst deactivation. The metal Mo active sites promoted dehydrogenation coupling and hydrogen transfer during coke formation, forming a more highly disordered multiring structure, and the metal Co active sites were more capable of decomposing macromolecular compounds, olefins and alkanes, and promoted the formation of graphite-like structural carbon.

One-dimensional biomass-based carbon nanotubes loaded with MoS2 as catalysts for the electrocatalytic nitrogen reduction reaction

In recent years, electrochemical conversion of nitrogen to ammonia at low temperature and atmospheric pressure has become a hot research topic because of its advantages of low carbon emission, low energy consumption and high energy transfer rate. The development of catalysts with high catalytic activity and flexibility are an important topic in the current nitrogen reduction reaction. In this paper, CNT@MoS2 composite catalysts were prepared by catalytic pyrolysis of biomass to prepare one-dimensional carbon nanotubes and then combined with MoS2 by a hydro thermal method. It was found that 120 CNT@MoS2 had better NRR activity and selectivity, NH3 yield rate of 21.2 μg h−1 mg−1 was achieved at −0.44 V vs. The Faraday efficiency can reach 5.4%. The catalytic performance is more than 3 times higher than CNT. The mechanism of MoS2-catalyzed NRR was further investigated by DFT theoretical calculations. The results of the theoretical calculations are in good agreement with the experimental results, providing a reasonable explanation for the high reduction performance of the catalyst. This study offered a promising avenue for exploring and rationalizing the design of electrocatalytic materials for NRR.

Characterization of the decomposition behaviors of catalytic pyrolysis of alkaline lignin with the addition of different concentrations of potassium

Investigating the influence of potassium concentration on alkali lignin pyrolysis is beneficial for advancing the technology of biomass catalytic pyrolysis. This study examined the catalytic effects of different concentrations of various potassium compounds on alkali lignin pyrolysis. The impregnation method was employed to load potassium compounds (KCl, K2CO3, and CH3COOK) onto alkali lignin at varying concentrations. The results showed a significant influence of potassium concentration on the catalytic pyrolysis of lignin. Increasing the potassium concentration resulted in higher pyrolysis char yield and lower pyrolysis gas yield. Furthermore, the pyrolytic char with a high concentration of potassium exhibited a distinct surface pore structure that was noticeably eroded by potassium. Furthermore, with an increase in potassium concentration, the removal of side chains, including methoxy, acetyl, and hydroxyethyl groups, became increasingly pronounced, resulting in higher yields of CO2 and phenol. The elevated potassium concentration facilitated the depolymerization of lignin through Cβ-O bond cleavage, promoted the decomposition of intermediate products, and enhanced the formation of small molecule products. Ultimately, a hypothetical mechanism explaining the influence of potassium concentration on alkali lignin pyrolysis was proposed. This study establishes a scientific foundation for the high-value utilization and resource development of alkaline lignin.

Catalytic pyrolysis of biomass to aromatics over bifunctional Ni/ZSM-5 catalysts assembled on rice husk-derived silica platform

Catalytic pyrolysis of biomass to aromatics over bifunctional Ni/ZSM-5 catalysts assembled on rice husk-derived silica platform

A novel three-stage ex-situ catalytic pyrolysis process for improved bio-oil yield and quality from lignocellulosic biomass

This study aims to improve the quality and yield of bio-oil produced from ex-situ catalytic pyrolysis of lignocellulosic biomass (sawdust) using a combination of stage catalysts with Al-MCM-41, HZSM-5, and ZrO2. The research employed various methods, including thermogravimetric analysis (TGA), differential scanning calorimetry, bench-scale experiments, and process simulations to analyze the kinetics, thermodynamics, products, and energy flows of the catalytic upgrading process. The introduction of ZrO2 enhances the yield of monoaromatic hydrocarbons (MAHs) in heavy organics. Compared with the dual-catalyst case, the MAHs yield escalates by approximately 344% at a catalyst ratio of 1:3:0.25. Additionally, GC-MS data indicate that the incorporation of ZrO2 promotes the deoxygenation reaction of the guaiacol compound and the oligomerization reactions of PAHs. The integration of ZrO2 as the third catalyst enhances the yield of heavy organics significantly, achieving 16.85% at a catalyst ratio of 1:3:1, which increases by nearly 35.6% compared to the dual-catalyst case. Also, the addition of ZrO2 as the third catalyst enhanced the energy distribution in heavy organics. These findings suggest that the combination of these catalysts improves the fuel properties and yields of the bio-oil.

Impact of Na at the low temperature Fe catalysis on high quality cellulose-based graphitic carbon

Biomass-based graphitic carbon is a promising material, but the effect mechanism of inherent alkali metals on the catalytic pyrolysis of biomass is still unclear. In this study, cellulose was selected as the model substance, and the influence mechanism of Na on the graphitization of cellulose catalytic pyrolysis was investigated through a combination of experiments and theoretical calculations. The results indicate that Na can interact with the carbon skeleton through van der Waals forces, thereby altering the spatial structure of graphite crystals and increasing the interlayer spacing of graphite by 27.7%. In addition, Na can coexist with Fe(III) in the form of oxides, while also increasing the reaction energy barrier of reverse hydroxylation and dehydration cyclization, decreasing the generation of reducing gases mainly composed of CO. This impedes the reduction of iron-based catalysts, thereby affecting the formation of the graphite microcrystalline structure. The research indicates that maintaining the ratio of Na content to iron-based catalysts within a 1:1 range is optimal for producing graphite carbon from cellulose.

Augmenting levoglucosan production through catalytic pyrolysis of biomass exploiting Ti3C2T MXene

Augmenting levoglucosan production through catalytic pyrolysis of biomass exploiting Ti3C2T MXene

Enhancement of aromatics and syngas production by co-pyrolysis of biomass and plastic waste using biochar-based catalysts in microwave field

In this study, O-rich biomass (bamboo) was co pyrolyzed with H-rich plastic waste (PE) based on the biochar-based catalysts to investigate the yield and quality of pyrolysis oil and syngas. Focusing on the variations of aromatics and phenolics, to reveal the synergetic mechanism between biomass and PE in microwave field. Biomass is “rich in O and lack of H″, and waste plastics are “rich in C and rich in O″ which can provide a lot of H radicals for catalytic pyrolysis of biomass, improve the quality of bio-oil. And the active factors of biomass effectively activated PE. The biochar-based catalysts further promoted deoxygenation and arylation reactions, intensifying the generation of aromatics and reducing oxygen-containing compounds (phenols, etc.). Bamboo: PE = 1: 3 catalyzed by Zr-modified biochar-based catalysts resulted in aromatics yielded as high as 74.13%, while phenols yields was only 9.39%. Incorporation of the externally H-donor PE promoted the growth of carbon chains, and the microwave field activated free radicals which facilitated the cyclization and arylation of carbon. The biochar-based catalysts also promoted the generation of high-value monocyclic aromatics by utilizing the selective ability in the microwave field. Finally, the coupled synergistic mechanism of co-pyrolysis in microwave field was proposed.

In-situ bio-oil directional conversion mechanism of catalytic biomass pyrolysis over nitrogen-doped carbon preparation by grading of nitrogen-rich cow dung

N-doped carbon catalysts were prepared using corn straw (CS) and cow manure (CD) as carbon and N resources, and used for the CS catalytic fast pyrolysis in Py-GCMS to improve the quality of bio-oil products. Through the methods combining hydrothermal treatment and carbonization, the N from CD was efficiently fixed into the straw biochar, showing the better catalytic effect. The moderate carbonization temperature (600 °C) and the lower HTC temperature benefited the improvement of N-doped biochars on the relative content of phenols in bio-oil, with the maximum increment of 8.32%. The pyridinic-N and pyrrolic-N in N-doped biochars mainly enhanced the relative content rather than the yields of phenols and ketones, respectively. Compared with the surface area and the degree of disorder, the types and content of N species in N-doped biochar had the greater promoting effect on the relative content of phenols in bio-oil.

Catalytic pyrolysis of biomass to produce bio‐oil using layered double hydroxides (LDH)‐derived materials

AbstractOwing to the enormous consumption of petroleum products and their environmental polluting nature, attention has been given to seeking alternative resources for the development of sustainable products. Biomass is a renewable source that can be converted to a variety of fuels and chemicals by different approaches, which are the best replacements for traditional petroleum‐derived products. Pyrolysis is a process in which chemical bonds of biomass macromolecules such as cellulose, hemicellulose, and lignin, are fractured into small molecular intermediates under high pressure, and results bio‐oil, biochar, and fuel gases as desired products. Of these pyrolysis products, bio‐oil is the primary product that usually contains large amounts of oxygen and nitrogen compounds that hinder its application potential. Catalytic pyrolysis is a beneficial method that is reported to alter the constituents and quality of bio‐oil and to upgrade them for diverse applications. Catalytic hydropyrolysis and copyrolysis of biomass are an alternative approaches to overcome the drawbacks raised toward product formation in the pyrolysis process. Layered double hydroxides (LDH) and their derived forms are well‐known catalytic/catalytic support materials for various chemical reactions due to their superior properties, such as easy preparation, thermal stability, and tuneable acid/base properties. This review summarizes the progress in the utilization of as‐synthesized LDH and their modified forms such as mixed metal oxides and functionalized/composite materials as active catalysts for the pyrolysis of various biomass sources.

Char-based Fe-Ni-Ca material for capturing AAEM from biomass pyrolysis volatiles and recyclability in catalytic reforming of volatiles

Hydrogen production derived from biomass catalytic pyrolysis has received increasing attention, to solve the excessive consumption of renewable energy. However, considerable amounts of the issues (e.g., slag formation, corrosion, and scaling on the heat exchange surface) related to alkali and alkali earth metals (AAEM) have hindered its application. To address these challenges and improve the yield of H2, char-based Fe-Ni-Ca material is proposed to capture AAEM from biomass pyrolysis volatiles while increasing the H2. Char-based materials exhibit excellent AAEM capture ability, with K, Na, and Mg contents detected in spent materials being 3.4 times, 1.4 times, and 1.5 times higher than those in fresh, respectively. Besides, the spent Fe-Ni-Ca exhibits excellent stability after regeneration, with H2 production comparable to that of fresh material, and CO production exceeding that of fresh Fe-Ni-Ca. It was disclosed that the char support can adsorb AAEM in volatiles, and then chemical reactions will occur between metal elements (Fe, Ni, and Ca) in the material and AAEM in the volatiles, trapping AAEM in the material and catalytic reforming volatiles. This work provides a novel strategy to deal with AAEM in volatiles.