Catalytic Pyrolysis Of Biomass Research Articles

The comparison of chemical liquid deposition and acid dealumination modified ZSM-5 for catalytic pyrolysis of pinewood using pyrolysis-gas chromatography/mass spectrometry

Catalyst deactivation is the main reason for low petrochemical yield in catalytic fast pyrolysis (CFP) of biomass. ZSM-5 catalysts modified by chemical liquid deposition (CLD) and acid dealumination (AD) were prepared to improve petrochemical yields for CFP of pinewood. The results showed that CLD by SiO2 led to the coverage of strong acid sites, while AD favored the removal of superficial acid sites. CFP of pinewood showed that the relative area ratio of BTX was boosted by 37.2% and 30.4% over modified ZSM-5 catalysts by CLD and AD, respectively. The yield of indenes and naphthalenes which were important precursors of heavy coke decreased sharply. Considering environmental cost and catalytic performance, CLD seems to be a preferable modification method over ZSM-5 in the catalytic pyrolysis of biomass for petrochemicals.

Catalytic conversion of biomass-derivates by in situ DRIFTS: Evolution of coke

Coke deposition in the catalytic fast pyrolysis of biomass includes active coke and inert coke, which promote or inhibit the formation of hydrocarbons. This study aims at the evolution of coke formation on various catalysts in the catalytic conversion of furan as an important intermediate from biomass fast pyrolysis. The functional groups on the surface of each catalyst at every moment were recorded by in situ diffuse reflectance Fourier transform infrared spectroscopy. The results indicated that the coke formation was closely related to the structure and acid property of the catalysts combined with catalytic tests in a fixed-bed reactor. Though dealumination only changed the acid distribution, it increased the hydrocarbon yield and introduced different chemical component of active coke. Because MCM-22 had a large internal space and small windows, its coke content should be quite large. However, the coke on MCM-22 did not show large molecules in this study because of the wide acid distribution, and similar active coke species with ZSM-5 were detected of polymethyl benzaldehyde. The coke content of HY was small because of large quantities of weak acid, although HY showed a significantly large internal space. The main components of active coke on HY and Hβ were diolefinic alcohols and polymethyl benzenes. The understanding of coke formation on various catalysts will provide guidelines for catalyst design, i.e., it is suggested that 3-dimensional structures such as MCM-22 with large supercages and small windows can be introduced into the original ZSM-5 system to form a core-shell catalyst to increase the hydrocarbon yields.

Catalytic fast pyrolysis of biomass to produce furfural using heterogeneous catalysts

Furfural is a valuable chemical, the production of furfural from renewable biomass resources becomes more attractive in recent years. In this study, biomass fast pyrolysis with heterogeneous catalysts (titanium compounds (TiN, TiO2 and TiOSO4) and metal nitrides (MoN, GaN and VN)) for furfural production was investigated experimentally by means of pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS). The measurement results indicated that TiN and GaN promoted the furfural compounds production notably mainly through direct decomposition of oligosaccharides. The formation of furfural was promoted when the amount of TiN was increased, and the yield of furfural formed was about 5.5 times the size of that from non-catalytic pyrolysis when TiN/cellulose mass ratio was 4. The furfural yield decreased when the pyrolysis residence time increased from 10 to 30s, which suggests competitive reactions (formation of 1, 6-anhydro-beta.-d-glucopyranose) against the formation of furfural. TiN, as a catalyst for fast pyrolysis towards furfural production, can be well applied to agriculture biomass residues. Comparing three biomass residues: corncob, wheat straw and cotton stalk, corncob showed higher furfural yield due to the higher holocellulose content, while wheat straw showed higher furfural selectivity.

Integrated Biorefining: Coproduction of Renewable Resol Biopolymer for Aqueous Stream Valorization

Phenol-formaldehyde resins are major material classes that are used in a range of applications including composites, adhesives, foams, electronics, and insulation. While efforts have been made to produce renewable resins, there has yet to be an approach that offers potential for economic viability and meets all critical quality metrics. This failure can be attributed largely to the use of phenol and cresol homologues and to high separation costs. In this work, the use of phenol, cresol, and alkyl phenols derived from the aqueous phase generated from catalytic fast pyrolysis of biomass to produce a high-quality biobased resin is demonstrated. Production, through catalytic fast pyrolysis (CFP), separation, through distillation and adsorption unit operations, and synthesis, through typical resol chemistry, produced a resin with properties, such as curing kinetics and molecular weight, competitive with petroleum-derived resin. This work explores a pathway to value-added coproducts from a CFP waste stream, whi...

Ex-situ catalytic fast pyrolysis of biomass over HZSM-5 in a two-stage fluidized-bed/fixed-bed combination reactor

Ex-situ and in-situ catalytic fast pyrolysis (CFP) of biomass over HZSM-5 were compared in a two-stage fluidized-bed/fixed-bed combination reactor. Ex-situ CFP gave a similar carbon yield of aromatics+olefins (∼20%) with in-situ CFP but produced much more olefins (10.3% vs. 5.8%) and less char+coke (42.7% vs. 48.4%). The effects of weight hourly space velocity (WHSV), carrier gas flow rate, pyrolysis temperature and catalysis temperature on product distribution in ex-situ CFP were further studied. The maximum carbon yield of aromatics+olefins (21.7%) was obtained at pyrolysis temperature of 550°C and catalysis temperature of 600°C with the highest carrier gas flow rate (1.2L/min) and WHSV of 1.33h−1. Obviously less coke was generated at higher pyrolysis temperature. When catalysis temperature increased to 700°C, ethylene and benzene carbon selectivities boosted to 79.4% and 60.5%, respectively.

The role of tailored biochar in increasing plant growth, and reducing bioavailability, phytotoxicity, and uptake of heavy metals in contaminated soil

Microwave-assisted catalytic pyrolysis was investigated using K3PO4 and clinoptilolite to enhance biochar sorption affinity for heavy metals. The performance of resulting biochar samples was characterized through their effects on plant growth, bioavailability, phytotoxicity, and uptake of heavy metals in a sandy soil contaminated with Pb, Ni, and Co. The produced biochars have high cation-exchange capacity (CEC) and surface area, and rich in plant nutrients, which not only reduced heavy metals (Pb, Ni, and Co), bioavailability and phytotoxicity, but also increased plant growth rate by up to 145%. The effectiveness of biochar in terms of reduced phytotoxicity and plant uptake of heavy metals was further improved by mixing K3PO4 and clinoptilolite with biomass through microwave pyrolysis. This may be due to the predominance of different mechanisms as 10KP/10Clino biochar has the highest micropore surface area (405 m2/g), high concentrations of K (206 g/kg), Ca (26.5 g/kg), Mg (6.2 g/kg) and Fe (11.9 g/kg) for ion-exchange and high phosphorus content (79.8 g/kg) for forming insoluble compounds with heavy metals. The largest wheat shoot length (143 mm) and lowest extracted amounts of Pb (107 mg/kg), Ni (2.4 mg/kg) and Co (63.9 mg/kg) were also obtained by using 10KP/10Clino biochar at 2 wt% load; while the smallest shoot length (68 mm) and highest extracted amounts of heavy metals (Pb 408 mg/kg, Ni 15 mg/kg and Co 148 mg/kg) for the samples treated with biochars were observed for soils mixed with 1 wt% 10Clino biochar. Strong negative correlations were also observed between biochar micropore surface area, CEC and the extracted amounts of heavy metals. Microwave-assisted catalytic pyrolysis of biomass has a great potential for producing biochar with high sorption affinity for heavy metals and rich nutrient contents using properly selected catalysts/additives that can increase microwave heating rate and improve biochar and bio-oil properties.

Biomass catalytic fast pyrolysis over hierarchical ZSM-5 and Beta zeolites modified with Mg and Zn oxides

Hierarchical ZSM-5 and Beta zeolites, loaded with MgO and ZnO, have been explored for the catalytic fast-pyrolysis of eucalyptus woodchips. These materials exhibit a high dispersion of the MgO or ZnO phases, which is probably due to the presence of a hierarchical porosity with both micro- and mesopores in the zeolitic supports. The incorporation of these metal oxides led to a significant reduction in the textural properties and to changes in the acidic properties of the parent zeolites. Thus, a decrease in the concentration of Bronsted acid sites was observed, which was accompanied by the generation of additional Lewis acid sites with medium strength. In addition, the incorporation of metal oxide promotes the formation of significant amount of basic sites, especially for the samples loaded with MgO. Catalytic fast pyrolysis experiments of eucalyptus woodchips were performed in a fixed bed reactor at 500 °C and atmospheric pressure under a nitrogen flow. In comparison with non-catalytic fast pyrolysis, the use of zeolitic catalysts caused a decrease in the bio-oil* (water free basis bio-oil) production due to enhanced formation of gases, as well as coke deposition on the catalyst. However, the quality of the bio-oil* was enhanced since the catalysts were able to decrease its oxygen content. In this way, h-ZSM-5-based catalysts showed a clearly deeper deoxygenation degree compared to those having h-Beta as support, with very low content of anhydro sugars and the formation of a significant amount of aromatics. Regarding the effect of the metal oxide phase, MgO-loaded samples provided bio-oil* with enhanced energy yields and lower oxygen content, probably due to the adequate balance of Lewis acid and basic sites. Likewise, significant differences were observed among the catalysts regarding the deoxygenation pathways and the compounds families present in the bio-oil*.

Deactivation of Multilayered MFI Nanosheet Zeolite during Upgrading of Biomass Pyrolysis Vapors

The catalytic fast pyrolysis (CFP) of biomass is a promising technology for producing renewable transportation fuels and chemicals. MFI-type catalysts have shown promise for CFP because they produce gasoline range hydrocarbons from oxygenated pyrolysis compounds; however, rapid catalyst deactivation due to coking is one of the major technical barriers inhibiting the commercialization of this technology. Coke deposited on the surface of the catalysts blocks access to active sites in the micropores leading to rapid catalyst deactivation. Our strategy is to minimize rapid catalyst deactivation by adding mesoporosity through formation of MFI nanosheet materials. The synthesized MFI nanosheet catalysts were fully characterized and evaluated for cellulose pyrolysis vapor upgrading to produce olefins and aromatic hydrocarbons. The data obtained from pyrolysis-GCMS (py-GCMS) showed that fresh MFI nanosheets produced similar aromatic hydrocarbon and olefin yields compared to those of conventional HZSM-5. However, ...

Catalytic Pyrolysis of Biomass and Plastic Mixtures Using HZSM-5 Zeolite

Abstract The catalytic effect of HZSM-5 zeolite was studied on the thermal decomposition of model waste mixtures of plastics and biomass. The influence of temperature and catalyst ratio as well as the hindering effect of cellulose and lignin on the catalytic decomposition of plastic waste was studied applying low and high heating rate by thermogravimetry/mass spectrometry (TG/MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), respectively. HZSM-5 catalyst reduced the thermal stability of plastic waste, but the catalytic effect was blocked in the presence of 50% cellulose or 10% lignin. Principal component analysis (PCA) has been applied to reveal correlations between the composition of pyrolysis products, pyrolysis temperature and proportion of the applied catalyst. The hindering effect of biomass can be compensated by applying higher catalyst ratio.

Production of syngas from pyrolysis of biomass using Fe/CaO catalysts: Effect of operating conditions on the process

This study aimed to further optimize the operating conditions to produce hydrogen-enriched syngas from the catalytic pyrolysis of biomass in a two-stage fixed-bed reaction system with the Fe/CaO catalyst derived from layered double hydroxides (LDHs) precursor. Specifically, the effects of catalyst calcination temperature and catalytic bed temperature on the composition and yield of syngas were investigated. Various characterization techniques such as XRD, SEM, BET, H2-TPR and CO2-TPD were employed to thoroughly characterize the Fe/CaO catalysts both before and after the catalytic reaction. It was found that the catalyst synthesized at a mild temperature of 600°C performed the best in producing hydrogen-enriched syngas, probably because of its uniform morphology, smaller particle size, superior reducibility and stronger CO2 absorption ability. In addition, higher temperature was found to benefit the syngas production due to the acceleration of reaction rate and promotion of secondary cracking and reforming reactions of heavy organic molecules with the maximum syngas yield of 63.0wt.% and H2 yield of 172mL/g biomass obtained at catalytic temperature of 800°C using Fe/CaO catalyst calcined at 600°C. Nevertheless, the H2/CO ratio was only at a suboptimal level of 0.99 because the decomposition of CaCO3 at higher catalytic temperature released CO2 and suppressed the water gas shift reaction to produce more H2.

Bio-gasoline Production by Coupling of Biomass Catalytic Pyrolysis and Oligomerization Process

Abstract Biomass catalytic cracking produced aromatics and olefins-rich fuel gas. In this paper, the C 5 -C 12 iso-olefins and iso-alkanes were produced by oligomerization of olefins-rich fuel gas. The amorphous silica-alumina (ASA) was used as catalyst for olefins oligomerization reaction. The conversion of ethylene, propylene and butylene reached 19.2%, 37.3% and 58.7%, respectively. The yield of C 5 -C 12 products reached 23.43c-mol%. The bio-gasoline was the mixture of the produced aromatics and C 5 -C 12 iso-alkanes. Results showed that 1Kg rice straw biomass could produce 0.226Kg bio-gasoline. The thermal efficiency from biomass to bio-gasoline reached 49.5%. Coke formation on the ASA catalyst resulted in the activity lost. After generation by combustion of the deposited coke, the properties of spent ASA catalyst was recovered. Coupling of biomass catalytic pyrolysis and olefins oligomerization to bio-gasoline is an excellent approach with high efficiency.

Catalytic co-pyrolysis of torrefied yellow poplar and high-density polyethylene using microporous HZSM-5 and mesoporous Al-MCM-41 catalysts

The catalytic pyrolysis of lignocellulosic biomass with aluminosilicate catalysts is a promising method for the direct production of liquid hydrocarbon fuels consisting mainly of aromatic compounds (e.g., benzene, toluene, and xylenes). On the other hand, the economic and commercial viability of this process is limited by the low yields of aromatic hydrocarbons. In this study, the effects of biomass torrefaction, co-feeding of plastic wastes, their combination, and the catalytic upgrading mode (in-situ vs ex-situ) on the aromatic formation efficiency during the catalytic pyrolysis of yellow poplar were evaluated systematically to maximize the production of aromatic hydrocarbons. Two representative catalysts for catalytic pyrolysis (i.e., microporous HZSM-5 and mesoporous Al-MCM-41) were used in this case study. The torrefaction of yellow poplar led to the enhanced production of aromatic hydrocarbons in the catalytic co-pyrolysis of yellow poplar and high-density polyethylene over both catalysts. The experimental yields of aromatic hydrocarbons from the catalytic co-pyrolysis of torrefied yellow poplar and high-density polyethylene were also higher than their theoretical yields, highlighting the synergistic aromatic formation by the interaction of torrefied yellow poplar and high-density polyethylene. Between the two catalysts, microporous HZSM-5 exhibited much higher activity for aromatic production from catalytic co-pyrolysis owing to its strong acidity and appropriate pore structure. Compared to ex-situ catalytic co-pyrolysis, the in-situ catalytic co-pyrolysis of torrefied yellow poplar and high-density polyethylene produced larger amounts of aromatic hydrocarbons due to the more effective contact between the pyrolysis vapors and HZSM-5.

(Invited) Integrating Theory and Experiment to Design and Develop Advanced Materials for the Production of Transportation Fuels Via Catalytic Fast Pyrolysis of Biomass: Transition Metal Carbides and Phosphides

As part of the DOE’s Energy Materials Network, the Chemical Catalysis for Bioenergy (ChemCatBio) Consortium seeks to overcome catalysis challenges for biomass conversion processes through the design and development of advanced catalytic materials. One such challenge being addressed by the consortium is for the catalytic fast pyrolysis (CFP) conversion process, in which biomass is heated to approximately 500°C at short contact times producing a vapor stream of over 300 different oxygenated organic compounds. This complex mixture is subsequently upgraded in the vapor phase over a heterogeneous catalyst to remove oxygen and improve the fuel properties of the condensed bio-oil. For this process, carbon efficiency has the greatest impact on the overall economics, and currently-available catalysts suffer from short lifetimes due to coke deposition and poor yields to the desired fuel-range products. To address this challenge, the ChemCatBio consortium initiated a joint experimental and computational effort to design and develop advanced CFP catalysts based on transition metal carbide and phosphide formulations. This effort links catalyst evaluation at multiple scales, ranging from intrinsic kinetic measurements with model compounds at the mgcat scale to bio-oil production from a pine feedstock at the 100gcat scale, with computational modeling of the catalyst surface termination under reaction conditions, calculation of reaction energetics, and ultimately the integration of those energetics into a micro-kinetic model validated with experimental data. The results generated from this integrated approach are used to inform the synthesis of targeted catalyst formulations with desired properties. This presentation will provide an overview of this effort and, in the spirit of the ECS conference, will also briefly discuss the electrocatalytic properties of these transition meal carbide and phosphide materials.

A study of guaiacol, cellulose, and Hinoki wood pyrolysis with silica, ZrO2&TiO2 and ZSM-5 catalysts

Catalytic pyrolysis of biomass is often used to improve bio-oil quality and energy content. In order to better understand the interactions between various catalysts and biomass components, individual components of biomass were isolated and pyrolyzed with different catalysts. Understanding the interactions between pyrolysis vapors and catalysts is important to create catalysts that can improve bio-oil quality and energy content in the future. In this study, cellulose, guaiacol (as a model for lignin), and Hinoki wood were pyrolyzed and catalyzed with silica, ZrO2&TiO2, and ZSM-5 with an SiO2-to-Al2O3 (SAR) ratio of 40 and 1500. GC–MS analysis was used to measure the effects of the different catalysts on the pyrolysis vapors. It was found that silica had a strong interaction with the hydroxyl groups of levoglucosan and significantly decreased sugars in both cellulose and Hinoki wood pyrolysis. ZrO2&TiO2 increased the amount of cyclopentanones and aromatics with Hinoki wood pyrolysis. The ZSM-5 catalysts also increased aromatic hydrocarbons and oxygenated hydrocarbons with Hinoki wood pyrolysis. Based on these results, specific reactions of the catalysts were proposed. Additionally, ZSM-5 with a SAR ratio of 1500 has very few acidic sites, so the steric effects of ZSM-5 could be isolated. These results are discussed and contrasted with ZSM-5 with a SAR ratio of 40. These results show that microporous catalysts and moderate acidity are optimal for improving bio-oil quality.

Modelling of Biomass Catalytic Pyrolysis: Mixing/Segregation of Biomass and Catalyst in Bubbling Fluidized Beds

Modelling of Biomass Catalytic Pyrolysis: Mixing/Segregation of Biomass and Catalyst in Bubbling Fluidized Beds

Catalyst Residence Time Distributions in Riser Reactors for Catalytic Fast Pyrolysis. Part 2: Pilot-Scale Simulations and Operational Parameter Study

Using the validated simulation model developed in part one of this study for biomass catalytic fast pyrolysis (CFP), we assess the functional utility of using this validated model to assist in the development of CFP processes in fluidized catalytic cracking (FCC) reactors to a commercially viable state. Specifically, we examine the effects of mass flow rates, boundary conditions (BCs), pyrolysis vapor molecular weight variation, and the impact of the chemical cracking kinetics on the catalyst residence times. The factors that had the largest impact on the catalyst residence time included the feed stock molecular weight and the degree of chemical cracking as controlled by the catalyst activity. Because FCC reactors have primarily been developed and utilized for petroleum cracking, we perform a comparison analysis of CFP with petroleum and show that the operating regimes are fundamentally different.

Thermogravimetric analysis of the biomass pyrolysis with copper slag as heat carrier

Thermo gravimetric analysis experiments were carried out on pyrolysis of three kinds of biomasses by temperature programming method. Employed by thermogravimetric analyzer, the effects of the type of biomass and the ratio of copper slag addition on pyrolysis were studied. Biomass pyrolysis process can be divided into four stages, dehydration, pre-pyrolysis, pyrolysis and carbonization. The experimental yields in this paper were modeled by CH4, C2H6, C3H8, C2H4 and C3H6, considering first-order primary reaction and reactions of alkanes and alkenes. Copper slag is beneficial for biomass pyrolysis. With Coats–Redfern method, nonlinear regression of biomass catalytic pyrolysis showed that reaction mechanism of pyrolysis process confirms well with shrinking core model (A3). The kinetic parameters and equations were also calculated. Copper slag promotes both the primary reactions of biomass pyrolysis and the Cracking reactions of alkanes and alkenes, but it cannot decrease the activation energy effectively.

Role of Potassium Exchange in Catalytic Pyrolysis of Biomass over ZSM-5: Formation of Alkyl Phenols and Furans

Catalytic fast pyrolysis of biomass with ZSM-5 type zeolites is a commonly considered in situ upgrading technique for the production of partially deoxygenated bio-oils. The acidity and structure of ZSM-5 catalysts favor the production of aromatic hydrocarbons from oxygenates present in the pyrolysis vapors, such as acids, anhydrosugars, ketones and aldehydes. However, these acid catalyzed deoxygenation pathways remove functional groups from the aromatic ring structure, which makes the liquid bio-oil more amenable to processing in current petroleum refineries while subsequently decreasing the value of the compounds as industrial chemical feedstocks. The observation of improved yields of alkyl phenols and furans during catalyst deactivation suggests a method for tuning the product distribution by altering the parent zeolite catalyst via changes in acidity and/or incorporation of alkali metals known to accumulate on the catalyst during pyrolysis. Here, we report the catalytic fast pyrolysis of three biomass ...

A review of catalytic microwave pyrolysis of lignocellulosic biomass for value-added fuel and chemicals

Lignocellulosic biomass is an abundant renewable resource and can be efficiently converted into bio-energy by a bio-refinery. From the various techniques available for biomass thermo-chemical conversion; microwave assisted pyrolysis (MAP) seems to be the very promising. The principles of microwave technology were reviewed and the parameters for the efficient production of bio-oil using microwave technology were summarized. Microwave technology by itself cannot efficiently produce high quality bio-oil products, catalysts are used to improve the reaction conditions and selectivity for valued products during MAP. The catalysts used to optimize MAP are revised in the development of this article. The origins for bio-oils that are phenol rich or hydrocarbon rich are reviewed and their experimental results were summarized. The kinetics of MAP is discussed briefly in the development of the article. Future prospects and scientific development of MAP are also considered in the development of this article.

Reforming Biomass Derived Pyrolysis Bio-oil Aqueous Phase to Fuels

Fast pyrolysis and catalytic fast pyrolysis (CFP) of biomass produce a liquid product stream comprised of various classes of organic compounds having different molecule size and polarity. This liquid, either spontaneously in the case of catalytic fast pyrolysis or by water addition for the noncatalytic process separates into a nonpolar organic-rich fraction and a highly polar water-rich fraction. The organic fraction can be used as a blendstock or feedstock for further processing in a refinery while, in the CFP process design, the aqueous phase is currently sent to wastewater treatment, which results in a loss of residual biogenic carbon present in this stream. This work focuses on the catalytic conversion of the biogenic carbon in pyrolysis aqueous phase streams to produce hydrocarbons using a vertical microreactor coupled to a molecular beam mass spectrometer (MBMS). The MBMS provides real-time analysis of products while also tracking catalyst deactivation. The catalyst used in this work was HZSM-5, whi...