Catalytic Fast Pyrolysis Of Biomass Research Articles

Microwave-Assisted Catalytic Fast Pyrolysis of Biomass for Hydrocarbon Production with Physically Mixed MCM-41 and ZSM-5

To delve into the law of hydrocarbon production in microwave-assisted catalytic fast pyrolysis (MACFP) of corn straw, physical mixed Mesoporous Crystalline Material-41 (MCM-41) and Zeolite Socony Mobile-5 (ZSM-5) catalyst prototypes were exploited in this study. Besides, the effects exerted by temperature of reaction and MCM-41/ZSM-5 mass ratio were explored. As revealed from the results, carbon outputs of hydrocarbons rose initially as the temperature of MACFP rose and reached the maximal data at 550 °C; subsequently, it declined as reaction temperature rose. Moreover, the MCM-41/ZSM-5 mass ratio of 1:2 was second-to-none for hydrocarbon formation in the course of biomass MACFP. It was reported that adding MCM-41 can hinder coke formation on ZSM-5. Furthermore, MCM-41/ZSM-5 mixture exhibited more significant catalytic activity than ZSM-5/MCM-41 composite, demonstrating that hydrocarbon producing process can be stimulated by a simple physical MCM-41 and ZSM-5 catalysts mixture instead of synthesizing complex hierarchically-structured ZSM-5/MCM-41 composite.

Catalytic fast pyrolysis of biomass with Ni-P-MCM-41 to selectively produce levoglucosenone

Levoglucosenone (LGO) is a valuable chiral synthon and can be produced from pyrolysis of cellulose and biomass. In the present study, Ni-P-MCM-41 catalysts with various P-to-Ni ratios were prepared and employed for selective production of LGO from biomass. Both analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale experiments were conducted to explore the effects of several factors on the formation of LGO, including P-to-Ni ratio in Ni-P-MCM-41, catalyst/sample ratio and pyrolysis temperature. The results revealed that all the Ni-P-MCM-41 catalysts, especially the one with a P-to-Ni ratio of 5, exhibited excellent catalytic capability and selectivity for LGO production. For Py-GC/MS, the maximal LGO yields of 27.34 wt% and 14.30 wt% were achieved from cellulose and pine at 350 °C with catalyst/cellulose ratio of 3 and catalyst/pine ratio of 2, respectively. While in lab-scale experiments, the highest LGO yields from cellulose and pine were 21.37 wt% and 10.71 wt%, with the corresponding selectivity of 78.31% and 53.75%, respectively. The Ni-P-MCM-41 catalyst possessed much better catalytic efficiency on the LGO production than previously reported catalysts, including H2SO4, H3PO4, solid superacid, solid phosphoric acid and activated carbon.

Naphthalene and Alkyl Naphthalene from Catalytic Fast Pyrolysis of Biomass Over ZSM-5 Aggregates

Seed-induced synthesis of ZSM-5 aggregates was carried out without organic templates. The prepared ZSM-5 aggregates were used upgrading polar sawdust-derived pyrolytic vapors for the selective production of naphthalene and alkyl naphthalene. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were conducted to analyze the pyrolytic product distribution and evaluate the catalyst performance. Due to the mesopores and proper acidities of ZSM-5 aggregates, the yield of naphthalene and methylnaphthalene over ZSM-5 aggregates were 36.0 and 123.7 mg/g, which were 2.7 and 2.6 times of those respectively over the commercial ZSM-5. The total selectivities of naphthalene and alkyl naphthalene could reach 61.56%.

Production of Phenolic-Rich Bio-Oil from Catalytic Fast Pyrolysis of Biomass Over Tailored Fe-Based Catalysts

The objective of this study is to catalytically upgrade fast pyrolysis vapors of sawdust using various Fe-based catalysts for producing phenolic-rich bio-oil by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique. A variety of parameters, including support characteristic, calcination temperature, pyrolysis temperature, as well as the catalyst-to-biomass ratio during the pyrolysis process were evaluated for their effects on product distribution of bio-oil. GC-MS analysis showed that compared to Fe–Mg and Fe–Al catalysts, the developed Fe–Ca catalyst significantly promoted the formation of phenols and its derivatives. The phenolic concentration declined with increasing calcination temperature and pyrolysis temperature, while increased monotonically along with increasing catalyst-to-biomass ratio. The phenolics concentration was high upto 81% (peak area) under optimum conditions of calcination temperature of 500 °C, pyrolysis temperature of 600 °C and catalyst-to-biomass ratio of 10. At higher catalyst-to-biomass ratio of 20, phenolics (88.03% in peak area) and hydrocarbons (including 7.86% of aromatics and 4.1% aliphatics) were the only two components that can be detected, with all the acids, aldehydes and ketones completely eliminated. This indicated the excellent capability of developed Fe–Ca catalyst in promoting the decomposition of lignin in biomass to generate phenolic compounds and meanwhile inhibiting the devolatilization of holocellulose.

Upgrading of furans from in situ catalytic fast pyrolysis of xylan by reduced graphene oxide supported Pt nanoparticles

Fast pyrolysis has been recognized as an efficient and feasible way to produce liquid fuels from biomass. For the aim to upgrade the products from fast pyrolysis of hemicellulose, reduced graphene oxide supported Pt nanoparticles (Pt/RGO) was adopted as catalyst for in situ catalytic fast pyrolysis (CFP). Pt/RGO was prepared by one-step thermal reduction method, and further employed as catalyst for in situ CFP of xylan. Online single-photon ionization time-of-flight mass spectrometry was employed to detect the volatile products, and furans were chosen as the model compounds. The experimental results showed that Pt/RGO distinctly increased the intensity of furans products from xylan pyrolysis, as the increase rates were respectively 80.5%, 64.4% and 50.2% in 400 °C, 500 °C and 600 °C. Furthermore, Pt/RGO can accelerate the process of xylan pyrolysis and be effective in eliminating oxygen for furans products. With addition of Pt/RGO, O/C ratio for furans products decreased from 0.38 to 0.32 in 400 °C, 0.37 to 0.32 in 500 °C, and 0.35 to 0.32 in 600 °C, respectively. This work proved that Pt/RGO had the potential to be a highly efficient catalyst for upgrading of the volatile products from in situ CFP of biomass.

Hybridization of ZSM‐5 with Spinel Oxides for Biomass Vapour Upgrading

AbstractIn this study, we report catalytic fast pyrolysis of biomass using multifunctional hybrid spinel‐oxide@zeolite catalysts prepared by using the steam‐assisted crystallization (SAC) method to create the mesoporous zeolite followed by urea hydrolysis of metal nitrates to deposit spinel‐oxides. This hybrid catalyst was quite effective in the deoxygenation of pinewood sawdust pyrolysis vapours, while avoiding over cracking of the lignin precursors, which are already ideal as chemical and fuel precursors. In the first step, multiple spinel oxides MgB2O4 (where B=Fe, Al, Ce, Ga, Cr) were screened as catalysts for the pyrolysis of pinewood sawdust and the resultant bio‐oil (bio‐oil on the water‐free basis) was assessed in terms of carbon efficiency, oxygen content and chemical composition. While all the tested spinel oxides deoxygenated the pyrolysis vapour, MgAl2O4 and MgFe2O4 were found to provide a well‐balanced deoxygenation degree and producing bio‐oil with acceptable carbon efficiency. Catalytic activity and product distribution were affected by the density and strength of the acid sites of the spinel oxides. Subsequently, CFP over MgFe2O4@ZSM5 and MgAl2O4@ZSM5 was investigated under similar condition. The better performance of the hybrid catalyst was attributed to the deposition of small particles of MgFe2O4 in the external surface of the zeolite. The presence of this spinel oxide on the external surface depolymerized bulky oxygenates to lighter fractions that could easily access the active sites within the mesoporous structure of the zeolite, thus providing the catalytic function needed for the oxygen removal after aromatic ring saturation.

Ga/ZSM-5 catalyst improves hydrocarbon yields and increases alkene selectivity during catalytic fast pyrolysis of biomass with co-fed hydrogen

An integrated experimental and computational study to understand the catalytic upgrading of biomass vapors into high yield of alkenes.

Controlling Deoxygenation Pathways in Catalytic Fast Pyrolysis of Biomass and Its Components by Using Metal-Oxide Nanocomposites.

SummarySelectively breaking the C-O bonds within biomass during catalytic fast pyrolysis (CFP) is desired, but extremely challenging. Herein, we develop a series of metal-oxide nanocomposites composed of W, Mo, Zr, Ti, or Al. It is demonstrated that the nanocomposites of WO3-TiO2-Al2O3 exhibit the highest deoxygenation ability during CFP of lignin, which can compete with the commercial HZSM-5 catalyst. The nanocomposites can selectively cleave the C-O bonds within lignin-derived phenols to form aromatics by direct demethoxylation and subsequent dehydration. Moreover, the nanocomposites can also achieve the selective breaking of the C-O bonds within xylan and cellulose to form furans by dehydration. The Brønsted and Lewis acid sites on the nanocomposites can be responsible for the deoxygenation of lignin and polysaccharides, respectively. This study provides new insights for the rational design of multifunctional catalysts that are capable of simultaneously breaking the C-O bonds within lignin and polysaccharides.

Investigating the Effect of Mono- and Bimetallic/Zeolite Catalysts on Hydrocarbon Production during Bio-oil Upgrading from Ex Situ Pyrolysis of Biomass

Catalytic fast pyrolysis of biomass offers an opportunity for upgrading of pyrolysis bio-oils using mono- and bimetallic-supported catalysts, which have been demonstrated to improve the bio-oil qua...

Solvent-free synthesis of jet fuel by aldol condensation and hydroprocessing of cyclopentanone as biomass-derivates

The conversion of biomass to jet fuel by thermochemical methods has become attractive to achieve the disposal of wastes and the production of highly valued fuels and chemicals. Aldol condensation of cyclopentanone from biomass catalytic fast pyrolysis and hydroprocessing of condensates were performed over Mg–Al–O and Ni/γ-Al2O3 to produce jet fuel under solvent-free conditions. The analysis of the carbon flow revealed that 37 carbon mole (CM) C10 alkane and 28 CM C15 alkane can ultimately be obtained from 100 CM cyclopentanone. Condensation catalyst with the Mg/Al mole ratio of 3:1 performed best due to its higher strength of weak and medium basic sites. Aldol condensation of cyclopentanone was confirmed to be a consecutive reaction that was obviously promoted at higher temperature. With regard to hydroprocessing, the yield of alkanes was greatly increased to 83.79% at 260 °C. Hydroprocessing of dimers and trimers followed very different pathways, and dimeric alcohols and trimeric alkenes played the role of important intermediates respectively. This study advances the development of jet fuel production from sustainable and green sources, providing a theoretical foundation for technology optimization and catalysts design.

The role of catalyst acidity and shape selectivity on products from the catalytic fast pyrolysis of beech wood

The catalytic fast pyrolysis (CFP) of biomass represents an efficient integrated process to produce deoxygenated stable liquid fuels and valuable chemical products from lignocellulosic biomass. The zeolite ZSM-5 is a widely studied catalyst for the CFP process. However, its microporous structure may limit the diffusion of high molecular weight pyrolysis intermediates to its active sites. Mesoporous aluminosilicates such as Al-SBA-15 are promising materials with larger pore sizes that can overcome these diffusional limitations. Previous comparisons between mesoporous aluminosilicates and ZSM-5 for the CFP process have neglected the disproportionately high acidity of ZSM-5. In this study, an Al-SBA-15 catalyst has been synthesised with high acidity, comparable to that of a ZSM-5 catalyst with a Si:Al ratio of 15:1. The synthesised Al-SBA-15 catalyst was characterised by N2 physisorption, XRD and propylamine-TPD, and was compared to a ZSM-5 catalyst and a typical industrial equilibrium fluid catalytic cracking catalyst (e-FCC). All three catalysts were used at three different catalyst to biomass (C/B) ratios, to investigate the effect of varying concentrations of acid sites on the product distribution from the catalytic fast pyrolysis of beech wood. Interestingly, despite their dissimilar structural architectures, all three solid acid catalysts displayed similar reaction pathways towards the cracking of high molecular weight products such as levoglucosan and formation of intermediates including phenolics and furans. However, the selectivity towards the final catalytic products was dictated mainly by the structure of the catalysts. Despite their very similar surface area and acidity, the ZSM-5 exhibited high selectivity for the formation of desirable aromatic hydrocarbon products due to its shape-selective micropore structure, while Al-SBA-15 instead shifted the selectivity towards the formation of undesirable coke. The results highlighted the importance of catalyst shape-selectivity in the catalytic fast pyrolysis of biomass for the conversion of pyrolysis vapours into desirable products and the suppression of undesirable solid byproduct formation.

Optimizing the Aromatic Product Distribution from Catalytic Fast Pyrolysis of Biomass Using Hydrothermally Synthesized Ga-MFI Zeolites

A series of gallium-containing MFI (Ga-MFI) zeolites with varying Ga2O3/Al2O3 ratios were synthesized using hydrothermal synthesis and tested as catalyst in catalytic fast pyrolysis (CFP) of beech wood for aromatic production. The results show that the incorporation of Ga slightly reduced the effective pore size of Ga-MFI zeolites compared to conventional HZSM-5 zeolites. Therefore, the Ga-MFI zeolites increased the aromatic selectivity for smaller aromatics such as benzene, toluene, and p-xylene and decreased the aromatic selectivity for bulkier ones such as m-xylene, o-xylene, and polyaromatics in CFP of beech wood relative to HSZM-5. In particular, the yield and selectivity of p-xylene, the most desired product from CFP of biomass, increased considerably from 1.64 C% and 33.3% for conventional HZSM-5 to 2.98–3.34 C% and 72.1–79.6% for the synthesized Ga-MFI zeolites. These results suggest that slightly reducing the pore size of MFI zeolite by Ga incorporation has a beneficial effect on optimizing the aromatic selectivity toward more valuable monoaromatic products, especially p-xylene, during CFP of biomass.

Production of acetonitrile via catalytic fast pyrolysis of biomass derived polylactic acid under ammonia atmosphere

In this study, a series of catalysts including different metal oxides loading on HZSM-5(Si/Al = 25) and cobalt oxides loading on different supports were synthesized to catalyze fast pyrolysis (CFP) of biomass derived polylactic acid (PLA) to produce acetonitrile under ammonia atmosphere. Both the metal and the acid of the catalyst had a crucial influence on the yield of acetonitrile and Co/HZSM-5(25) produced most acetonitrile. Other factors that might affect the product distribution including cobalt loading, reaction temperature, resident time and NH3 flow rate have been investigated systematically. Under the optimized CFP condition (650 ℃; resident time 2.4 s; NH3 flow rate 80 ml/min), the carbon yield and selectivity of acetonitrile in liquid product reached 50.2% and 83.6%, respectively. The possible reaction pathway from PLA to acetonitrile was also studied and proposed. PLA firstly cracked into lactic acid through thermal decomposition and formed lactide at the same time. Then lactic acid and lactide cracked into low-molecular aldehydes, ketones and acids. These aldehydes and ketones reacted with ammonia to form imines, acids to amides, and finally to acetonitrile and small amount of proponitrile under the catalysis of Co/HZSM-5 catalyst.

Mild hydrotreating of bio-oils with varying oxygen content produced via catalytic fast pyrolysis

Several biomass catalytic fast pyrolysis oils produced over HZSM-5 at varying levels of catalyst of deactivation, and therefore exhibiting oxygen contents ranging from 6 wt% to 33 wt% (enabled due to catalyst deactivation) were subjected to mild hydrotreating over Ru/C at 140 °C. The purpose of this study was to evaluate the performance of these catalytic pyrolysis oils in this process, which is often used as a stabilization step prior to exposure of the bio-oil to more severe hydrodeoxygenation conditions in pyrolysis based biorefinery concepts. This will help better define the desired deoxygenation rate during CFP, and inform decisions about yield/quality and cost tradeoffs during CFP. High liquid product recoveries were achieved for the mild hydrotreating in all samples with varying O-contents, meaning the yield of hydrogenated liquids from biomass was nearly exclusively dependent on the catalytic pyrolysis step. However, a trend was observed that the bio-oils were more responsive to the hydrogenation with increasing oxygen content. For example, no aromatic ring hydrogenation was observed for the bio-oils with <20 wt% oxygen content but ring saturation was observed for bio-oils with oxygen contents of 25–30 wt%. The bio-oils with about 25–30% oxygen content had the largest increase in H/C ratio upon hydrogenation. This trend may be attributed in part to a solvent effect, where the more polar bio-oils acting as their own solvents, helped promote hydrogenation. With regard to product stability an increase in the average molecular weight of the bio-oils with >25 wt% oxygen content was observed for exposure to the hydrogenation conditions, suggesting some oligomerization occurred prior to hydrogenation in these cases. Taken together, bio-oils with about 25 wt% oxygen content responded well to the mild hydrotreatment and were stable to the conditions, and offered a 2–3 fold increase in carbon yield from biomass over the bio-oils that were more severely deoxygenated during catalytic pyrolysis. This suggests that severe reduction of oxygen in the CFP step may be not needed to economically produce fungible, stabilized biofuel intermediates in high carbon yield.

Diverse impact of α-Fe2O3 with nano/micro-sized shapes on the catalytic fast pyrolysis of pinewood: Py-GC/MS study

The feasibility of α-Fe2O3 catalyst addition in the in-situ catalytic fast pyrolysis of Pinewood was considered with the focus on the variation in its shape: nano-sized non-ideal spheres, nanotubes, hollow nano/microtubes, and octadecahedral crystals. Nano-sized spheres strongly promoted the formation of acetaldehyde, something that was also observed for the octadecahedral crystals. The formation of acids was primarily facilitated through the addition of nanotube catalysts and octadecahedral crystals. Newly formed alicyclic ketonic compounds were promoted through the addition of nano-sized spheres, hollow nano/microtubes, and octadecahedral crystals. The latter two catalysts also showed a moderate selectivity in the formation of furfural. All applied catalysts showed loss of activity, though at different degrees, on the formation of lignin derived phenolic compounds, which can be primarily attributed to favoring the formation of char with simultaneous release of CO2. All used α-Fe2O3 catalysts with different shapes maintained their original morphology after the rapid heating with the rate of 20 K/ms followed by catalytic fast pyrolysis at 500 °C, indicating that nanomaterials with targeted dimensions can be applied as catalysts in the catalytic fast pyrolysis of biomass to enhance conversion of undesired oxygenated compounds to higher quality bio-oil and valuable chemicals.

Catalyst deactivation, ash accumulation and bio-oil deoxygenation during ex situ catalytic fast pyrolysis of biomass in a cascade thermal-catalytic reactor system

In this work, we investigated the deactivation of a commercial ZSM-5 based catalyst during ex situ catalytic fast pyrolysis (CFP). The experimental runs were carried out in a novel cascade dual fluidized bed reactor system where thermal pyrolysis of biomass was carried out in the first reactor, while ex situ catalytic conversion of the pyrolysis vapours was carried out in the second reactor. Consecutive reaction-regeneration cycles were realised using the same catalyst batch in order to evaluate catalyst deactivation over time. A comparison between in situ and ex situ CFP revealed that in contrast to what was observed in the case of in situ CFP, no accumulation of biomass-derived metals on the catalyst was observed during ex situ CFP. Both acidity and surface area were less affected compared to in situ CFP and the catalyst maintained higher activity. Product distribution and composition exhibited some variation over time which was attributed to the accumulation of biomass ash in the pyrolysis reactor and not to the poisoning of the catalyst bed. These results clearly demonstrated that ex situ CFP is an effective way to avoid catalyst poisoning during the CFP of biomass and to prolong catalyst lifetime.

Catalytic fast pyrolysis of biomass: Selective deoxygenation to balance the quality and yield of bio-oil

Firstly, the operating conditions were screened for biomass pyrolysis in a fixed bed with respect to higher oil yield. A temperature of 600 °C with an N2 flow of 80 ml/min exhibited the highest bio-oil yield. Then, the catalytic pyrolysis of biomass with various catalysts (Al2O3, CaO, MgO, CuO, Fe2O3, NiO, ZnO, ZrO2, TiO2, HZSM-5 and MCM-41) was studied to identify the selective deoxygenation method with respect to improve bio-oil quality with smaller drop in bio-oil yield. With the addition of CaO, the oxygen was mainly removed in the form of CO2, while, in other cases, more oxygen was removed in the form of H2O. Furthermore, more decarboxylation or less dehydration is better for the balance between yield and deoxygenation amount, and the preferred decarboxylation would lead to a higher pH and lower moisture content of bio-oil.

Catalytic fast pyrolysis of biomass over core-shell HZSM-5@silicalite-1 in a bench-scale two-stage fluidized-bed/fixed-bed reactor

In order to inhibit the coke formation on the external surface of HZSM-5 during catalytic fast pyrolysis (CFP) of biomass, core-shell structured HZSM-5@silicalite-1 zeolite catalysts were hydrothermally synthesized through the growth of silicalite-1 along the surface of a commercial HZSM-5. The catalyst characterization results indicate that silicalite-1 outer shell layer was successfully formed on the HZSM-5 core particles. Silicalite-1 coating was proved to be effective to reduce the external acidity as well as keep the internal acidity and channel patency of core HZSM-5 by catalytic probe reactions. The catalytic performances of HZSM-5@silicalite-1 samples in CFP of biomass were investigated using a bench-scale continuous feeding two-stage fluidized-bed/fixed-bed combination reactor. The results show that the productions of olefins and BTX were promoted (especially BTX), while the formations of catalyst coke and PAHs were significantly inhibited after silicalite-1 coating.

Overview of catalytic upgrading of biomass pyrolysis vapors toward the production of fuels and high‐value chemicals

The application of heterogeneous catalysis in biomass pyrolysis is considered as one of the most promising methods to improve bio‐oil quality by minimizing its undesirable properties (high viscosity, corrosivity, instability, etc.) and producing renewable fuels and high‐value chemicals. Catalytic fast pyrolysis (CFP) of biomass refers both to the “in situ” and “ex situ or two‐stage” upgrading. A plethora of catalytic materials have been investigated in the literature for both approaches, including conventional microporous zeolites, ordered mesoporous aluminosilicates, promoted or not with several transition metals, as well as various metal (nano)oxide catalysts with Lewis acidity. Recently, hybrid micro/mesoporous and basic materials have been also suggested exhibiting most promising results due to combined micro/mesoporosity and adequate balance of acid and basic sites. Optimum catalysts are required to retain deoxygenation, enhance yields of aromatics, and other valuable compounds (such as phenolics), while limiting coke formation. Coke formation is one of the reasons of catalyst deactivation; a very challenging issue during biomass CFP, especially using zeolites. The deactivation process is affected by many factors, including the composition of the feedstock (inorganic minerals present in the feedstock may also deposit on the catalyst), reaction conditions, and the nature/properties of the catalysts used in CFP. Precoking on the surface of zeolites or MgO deposition are among the proposed effective ways to suppress coke formation and thus, catalyst deactivation.This article is categorized under: Bioenergy &gt; Science and Materials Energy Research &amp; Innovation &gt; Science and Materials Energy and Transport &gt; Science and Materials

Synthesis and physicochemical characterization of hierarchical ZSM-5: Effect of organosilanes on the catalyst properties and performance in the catalytic fast pyrolysis of biomass

Abstract Two series of ZSM-5 catalysts with hierarchical porosity were hydrothermally synthesized by adding two types of organosilane reagents (OSA) into the medial synthesis system. The effects of the types and addition amounts of OSA on the pore characteristics, crystallinity, morphology and acidity of the ZSM-5 zeolites were studied by XRD, SEM, TEM, N2-adsorption, 27Al MAS NMR and NH3-TPD. Mesopores were generated by introducing appropriate amounts of OSA. In addition, the catalytic performance of the hierarchical ZSM-5s were investigated for the catalytic fast pyrolysis (CFP) of cellulose. The increase in the mesoporosity leads to a reduced amount of coke. However, the highest yield of aromatics was obtained for the mesoporous sample with the greatest microporosity. Thus, the right balance between meso- and microporosity is critical for achieving high aromatic yields. In addition, the distribution of aromatic products is directly related to the microporosity.