Catalytic Pyrolysis Of Biomass Research Articles

An integrated process for the production of lignocellulosic biomass pyrolysis oils using calcined limestone as a heat carrier with catalytic properties

The production of upgraded bio-oils by an integrated process using a mixture of calcined limestone and sand as a heat carrier with catalytic properties was experimentally studied at pilot scale. The integrated process consisted of two main steps: biomass catalytic pyrolysis in an Auger reactor for bio-oil production and char combustion in a fluidised-bed combustor for heat carrier heating and regeneration. A temperature of 450°C was fixed as an optimum value to carry out the catalytic pyrolysis step. Temperatures ranging from 700 to 800°C were assessed in the char combustor. Process simulation demonstrated that solid recirculation from the combustor to the pyrolysis reactor was marginally affected in this temperature range. However, an optimum char combustion temperature of 800°C was selected from an environmental point of view, since lower polyaromatic emissions were detected whilst NOx emissions were kept under the legislation limits. Under designated conditions, several pyrolysis-combustion cycles were carried out. A moderate deactivation of the catalyst by partial carbonation was found. This fact makes necessary the incorporation of a purge and an inlet of fresh heat carrier in order to maintain the bio-oil quality in the integrated process.

Biomass Catalytic Pyrolysis on Ni/ZSM-5: Effects of Nickel Pretreatment and Loading

In this work, Ni/ZSM-5 catalysts with varied nickel loadings were evaluated for their ability to produce aromatic hydrocarbons by upgrading of pine pyrolysis vapors. The effect of catalyst pretreatment by hydrogen reduction was also investigated. Results indicate that the addition of nickel increases the yield of aromatic hydrocarbons while simultaneously increasing the conversion of oxygenates, relative to ZSM-5, and these effects are more pronounced with increasing nickel loading. Additionally, while initial activity differences were observed between the oxidized and reduced forms of nickel on ZSM-5 (i.e., NiO/ZSM-5 versus Ni/ZSM-5), the activity of both catalysts converges with increasing time on stream. These reaction results coupled with characterization of pristine and spent catalysts suggest that the catalysts reach similar active states during catalytic pyrolysis, regardless of pretreatment, as NiO undergoes in situ reduction to Ni by biomass pyrolysis vapors. This reduction of NiO to Ni was confi...

Enhancement of biomass conversion in catalytic fast pyrolysis by microwave-assisted formic acid pretreatment

This study investigated microwave-assisted formic acid (MW-FA) pretreatment as a possible way to improve aromatic production from catalytic fast pyrolysis (CFP) of lignocellulosic biomass. Results showed that short duration of MW-FA pretreatment (5–10min) could effectively disrupt the recalcitrant structure of beech wood and selectively remove its hemicellulose and lignin components. This increased the accessibility of cellulose component of biomass to subsequent thermal conversion in CFP. Consequently, the MW-FA pretreated beech wood produced 14.0–28.3% higher yields (26.4–29.8C%) for valuable aromatic products in CFP than the untreated control (23.2C%). In addition, the yields of undesired solid residue (char/coke) decreased from 33.1C% for the untreated control to 28.6–29.8C% for the MW-FA pretreated samples. These results demonstrate that MW-FA pretreatment can provide an effective way to improve the product distribution from CFP of lignocellulose.

On the effectiveness of tailored mesoporous MFI zeolites for biomass catalytic fast pyrolysis

Optimum catalyst design plays a pivotal role in maximizing catalytic fast pyrolysis (CFP) bio-oil yield and quality. This work investigates the use of mordenite framework inverted (MFI) zeolites with hierarchical pore structures as potential catalysts to address the aforementioned challenges. Mesoporous MFI catalysts were created using both top-down and bottom-up approaches, were characterized and evaluated as CFP catalysts. CFP with mesoporous catalysts resulted in higher yields to aromatics and lower coke and char yields. The results of this study indicate that there is a maximum amount of mesopore volume required for optimal acid site accessibility leading to increased bio-oil production. After this maximum, intermediate aromatic hydrocarbons continue to polymerize to form bulky poly-cyclic aromatic hydrocarbons (PAHs) and coke.

Furan Production from Glycoaldehyde over HZSM-5

Catalytic fast pyrolysis of biomass over zeolite catalysts results primarily in aromatic (e.g., benzene, toluene, xylene) and olefin products. However, furans are a higher value intermediate for their ability to be readily transformed into gasoline, diesel, and chemicals. Here we investigate possible mechanisms for the coupling of glycoaldehyde, a common product of cellulose pyrolysis, over HZSM-5 for the formation of furans. Experimental measurements of neat glycoaldehyde over a fixed bed of HZSM-5 confirm furans (e.g., furanone) are products of this reaction at temperatures below 300 °C with several aldol condensation products as coproducts (e.g., benzoquinone). However, under typical catalytic fast pyrolysis conditions (>400 °C), further reactions occur that lead to the usual aromatic product slate. ONIOM calculations were utilized to identify the pathway for glycoaldehyde coupling toward furanone and hydroxyfuranone products with dehydration reactions serving as the rate-determining steps with typical...

Microwave-assisted catalytic pyrolysis of lignocellulosic biomass for production of phenolic-rich bio-oil

Catalytic microwave pyrolysis of peanut shell (PT) and pine sawdust (PS) using activated carbon (AC) and lignite char (LC) for production of phenolic-rich bio-oil and nanotubes was investigated in this study. The effects of process parameters such as pyrolysis temperature and biomass/catalyst ratio on the yields and composition of pyrolysis products were investigated. Fast heating rates were achieved under microwave irradiation conditions. Gas chromatography–mass spectrometry (GC–MS) analysis of bio-oil showed that activated carbon significantly enhanced the selectivity of phenolic compounds in bio-oil. The highest phenolics content in the bio-oil (61.19 %(area)) was achieved at 300°C. The selectivity of phenolics in bio-oil was higher for PT sample compared to that of PS. The formation of nanotubes in PT biomass particles was observed for the first time in biomass microwave pyrolysis.

Coprocessing of Catalytic-Pyrolysis-Derived Bio-Oil with VGO in a Pilot-Scale FCC Riser

A catalytic-pyrolysis-derived bio-oil, which was characterized by higher H/Ceff ratio and lower oxygen content in comparison to fast-pyrolysis-derived bio-oil, was coprocessed with VGO in a pilot-scale FCC riser. The addition of the bio-oil up to 10 wt % gave nearly equivalent oxygenate content and also similar selectivities of gasoline, bottom oil, and coke compared to those in VGO catalytic cracking alone, suggesting the catalytic-pyrolysis-derived bio-oil was a suitable feedstock for FCC coprocessing. However, the dry gas, including hydrogen and light alkane, was significantly decreased in the coprocessing experiment mainly because of the hydrogen transfer between bio-oil and VGO. Radiocarbon analysis of the product showed that 7% carbon of gasoline was derived from the bio-oil when 10 wt % bio-oil was added to VGO. The coprocessing of biomass catalytic pyrolysis and FCC was highly promising for biomass conversion into biofuel.

Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation

Bio-oil produced from conventional flash pyrolysis has poor quality and requires expensive upgrading before it can be used as a transportation fuel. In this work, a high quality bio-oil has been produced using a novel approach where flash pyrolysis, catalysis and fractionation of pyrolysis vapors using two stage condensation are combined in a single process unit. A bench scale unit of 1 kg/h feedstock capacity is used for catalytic pyrolysis in an entrained down-flow reactor system equipped with two-staged condensation of the pyrolysis vapor. Zeolite-based catalysts are investigated to study the effect of varying acidities of faujasite Y zeolites, zeolite structures (ZSM5), different catalyst to biomass ratios and different catalytic pyrolysis temperatures. Low catalyst/biomass ratios did not show any significant improvements in the bio-oil quality, while high catalyst/biomass ratios showed an effective deoxygenation of the bio-oil. The application of zeolites decreased the organic liquid yield due to the increased production of non-condensables, primarily hydrocarbons. The catalytically produced bio-oil was less viscous and zeolites were effective at cracking heavy molecular weight compounds in the bio-oil. Acidic zeolites, H-Y and H-ZSM5, increased the desirable chemical compounds in the bio-oil such as phenols, furans and hydrocarbon, and reduced the undesired compounds such as acids. On the other hand reducing the acidity of zeolites reduced some of the undesired compounds in the bio-oil such as ketones and aldehydes. The performance of H-Y was superior to that of the rest of zeolites studied: bio-oil of high chemical and calorific value was produced with a high organic liquid yield and low oxygen content. H-ZSM5 was a close competitor to H-Y in performance but with a lower yield of bio-oil. Online fractionation of catalytic pyrolysis vapors was employed by controlling the condenser temperature and proved to be a successful process parameter to tailor the desired bio-oil properties. A high calorific value bio-oil having up to 90% organics was produced using two staged condensation of catalytic pyrolysis vapor. Zeolite-based acidic catalysts can be used for selective deoxygenation, and the catalytic bio-oil quality can be further improved with staged vapor condensation.

In situ performance of various metal doped catalysts in micro-pyrolysis and continuous fast pyrolysis

Catalytic fast pyrolysis (CFP) of biomass is a promising route for the production of deoxygenated liquids suitable for further conversion to fuels and/or chemicals. In this work, CFP of pine wood in a micro-pyrolysis setup and a continuously operated bench-scale fast pyrolysis unit was performed to investigate the effect of catalyst type and reactor type on the products. In total, eight zeolite catalysts (metal doped acidic, basic, and γ-alumina catalysts and their parent counterparts) were tested. In the bench-scale unit, the distribution of products including liquid organics (i.e. CFP-oil), water, char, coke, and non-condensable gases (NCGs) were measured, as well as the compositions of the CFP-oil and NCGs. CFP gives rise to the production of additional water, coke, and NCGs at the expense of CFP-oil. However, the quality of the obtained CFP-oil was altered significantly depending on the catalyst type. For all catalysts, the acidity of CFP-oils remarkably decreased with an increased deoxygenation. The best performance was obtained with the lower redox-metal containing acidic catalyst and freshly calcined metal doped basic mixed-metal oxide catalysts. Py-GC/MS results obtained with the same catalysts were found to be only partially indicative for the performance of a catalyst in CFP of biomass.

Biomass catalytic pyrolysis: process design and economic analysis

The estimation of catalytic pyrolysis oil (CPO) production cost in a biomass catalytic pyrolysis (BCP) process is the objective of this study. Experiments carried out with a woody biomass (Beechwood) and a commercially available ZSM‐5 catalyst in a circulating fluid bed (CFB) reactor are the basis for the design of a commercial unit. In the CFB unit, the catalytic pyrolysis step takes place at 482°C and at a catalyst to biomass ratio of 15–20. Following this step, the vapor temperature exiting the reactor is cooled from 482 to 340°C by recovering energy for steam production. The vapors are condensed in two quench towers with recirculated oil and water. Following water separation, the CPO flows to storage. A commercial scale process was designed for a capacity of 180,000 metric tons (MT) per year (8 wt% moisture, 0.54 wt% ash) or 500 MT/day of moisture ash free (MAF) biomass (90% operating factor). The projected costs are valid only for an nth plant and they underestimate the cost for a first of its kind plant. Following procedures used for estimating investment and operating costs for a fluid catalytic cracking unit (FCCU), it is found that for BCP the estimated cost of producing CPO with 18 wt% oxygen is 615 US$/MT or 22 US$/GJ. A sensitivity analysis showed that the price of CPO could vary from 615 to 841 US$/MT (22–31 US$/GJ). On a crude oil energy equivalent basis, the bio‐oil cost lies in the range of 36–49 US$/GJ. WIREs Energy Environ 2016, 5:370–383. doi: 10.1002/wene.192This article is categorized under: Bioenergy > Science and Materials

Selective production of aromatic hydrocarbons from catalytic pyrolysis of biomass over Cu or Fe loaded mesoporous rod-like alumina

The selective production of aromatic hydrocarbons from bio-oil derived from the fast pyrolysis of sunflower stalks over Cu or Fe-modified mesoporous rod-like alumina catalysts was investigated.

Assessing biomass catalytic pyrolysis in terms of deoxygenation pathways and energy yields for the efficient production of advanced biofuels

The present work systematically studies the effect of the operation conditions of biomass catalytic pyrolysis on parameters like bio-oil oxygen content and mass yield, but also on additional indicators, such as the distribution of oxygen and chemical energy among the products.

Supported molybdenum oxides as effective catalysts for the catalytic fast pyrolysis of lignocellulosic biomass

Supported MoO3catalysts are effective catalytic fast pyrolysis catalysts that can generateca.30 C% hydrocarbons, including aromatics, olefins, and paraffins from pine.

Catalyst hydrothermal deactivation and metal contamination during the in situ catalytic pyrolysis of biomass

We investigated the effects of hydrothermal deactivation and biomass metal contamination on the properties and catalytic performance of commercial ZSM-5 catalysts.

Experimental Investigation of the Biomass Catalytic Pyrolysis Process to Produce the Combustible Gases with the High Calorific Value

The study is devoted to the low-temperature catalytic pyrolysis of biomass. The pyrolysis of peat was conducted using natural aluminosilicates and synthetic zeolites. It was found that the pore size of the mineral strongly affects the catalytic activity and provides the processing of the hydrocarbons forma-tion reactions. Bentonite clay was found to be the most effective catalyst for the biomass pyrolysis proc-ess. The use of bentonite clay as an addition to peat allows improving structural (strength, porosity) and sorption characteristics (sorption rate) of the molded compositions and can serve as a catalyst dur-ing its subsequent thermal conversion. The amount of gases obtained using natural aluminosilicate as a catalyst increased by 2 times compared to the non-catalytic process. The calorific value of the prod-ucts obtained was higher due to the light hydrocarbons formation. Copyright © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Coke formation of model compounds relevant to pyrolysis bio-oil over ZSM-5

Formation of coke during biomass catalytic pyrolysis deteriorates the selectivity to valuable liquid products and deactivates the catalyst, due to pore blocking and active site poisoning. In this work we investigate reaction mechanisms of coke formation and the structure of coke, formed from model compounds of relevance to biomass catalytic pyrolysis. Specifically, toluene, propylene, tolualdehyde and furan are catalytically pyrolyzed over ZSM-5, focusing on their yields to catalytic coke. Pyrolysis over inert silica is also performed, in order to understand the extent of thermal reactions. The pyrolysis product distribution of each model compound is presented and discussed in comparison with coke formation mechanisms proposed in the literature. It is shown that coke is mainly formed via oligomerization and polymerization of aromatic hydrocarbons and olefins. Catalytic reactions enhance the production of coke with higher crystallinity, less condensed structure and higher H/C ratio. Catalytic pyrolysis of toluene and tolualdehyde produces coke of similar structure, containing significant amounts of aliphatic carbons. Among the model compounds studied, furan produces the most condensed form of coke with no aliphatic carbons.

Selective production of nicotyrine from catalytic fast pyrolysis of tobacco biomass with Pd/C catalyst

A new technique was proposed to selectively produce nicotyrine, a valuable alkaloidal product, from catalytic fast pyrolysis of tobacco mixed with the Pd/C catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to investigate the effects of pyrolysis temperature and catalyst-to-tobacco ratio on the selective nicotyrine production. The actual nicotyrine yields under different reaction conditions were quantitatively determined. Moreover, the catalytic activity of the Pd/C catalyst was compared with those of the activated carbon (AC), Ru/C and Pd/SBA-15 catalysts. The results indicated that during the catalytic fast pyrolysis process, the Pd/C catalyst possessed promising dehydrogenation capability to selectively convert the nicotine in tobacco into the nicotyrine, and it performed much better than the other three catalysts. The maximal nicotyrine yield reached as high as 2.80wt%, obtained at the pyrolysis temperature of 400°C and catalyst-to-tobacco ratio of 2.

Production of phenolic-rich bio-oil from catalytic fast pyrolysis of biomass using magnetic solid base catalyst

A magnetic solid base catalyst (potassium phosphate/ferroferric oxide) was prepared and used for catalytic fast pyrolysis of poplar wood to selectively produce phenolic-rich bio-oil. Pyrolysis–gas chromatography/mass spectrometry experiments were conducted to investigate the effects of pyrolysis temperature and catalyst-to-biomass ratio on the product distribution. The actual yields of important pyrolytic products were quantitatively determined by the external standard method. Moreover, recycling experiments were performed to determine the re-utilization abilities of the catalyst. The results showed that the catalyst exhibited promising activity to selectively produce phenolic-rich bio-oil, due to its capability of promoting the decomposition of lignin to generate phenolic compounds and meanwhile inhibiting the devolatilization of holocellulose. The maximal phenolic yield was obtained at the pyrolysis temperature of 400°C and catalyst-to-biomass ratio of 2. The concentration of the phenolic compounds increased monotonically along with the increasing of the catalyst-to-biomass ratio, with the peak area% value increasing from 28.1% in the non-catalytic process to as high as 68.5% at the catalyst-to-biomass ratio of 7. The maximal total actual yield of twelve quantified major phenolic compounds was 43.9mg/g, compared with the value of 29.0mg/g in the non-catalytic process. In addition, the catalyst could be easily recovered and possessed promising recycling properties.

Conceptual Process Design and Techno-Economic Assessment of Ex Situ Catalytic Fast Pyrolysis of Biomass: A Fixed Bed Reactor Implementation Scenario for Future Feasibility

The Author(s) 2015. This article is published with open access at Springerlink.com Abstract Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid bio- fuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrol- ysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design report led by the National Renewable Energy Laboratory (NREL/ TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suit- able for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C-C coupling chem- istry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C-C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this study is based on future projections, the impacts of uncertainties in the underlying assumptions are quantified via sensitivity analysis. This analysis indicates that catalyst researchers should prioritize by: carbon efficiency(catalyst cost(catalyst lifetime, after initially testing for basic operational feasibility.

Optimizing anti-coking abilities of zeolites by ethylene diamine tetraacetie acid modification on catalytic fast pyrolysis of corn stalk

In order to minimize coke yield during biomass catalytic fast pyrolysis (CFP) process, ethylene diamine tetraacetie acid (EDTA) chemical modification method is carried out to selectively remove the external framework aluminum of HZSM-5 catalyst. X-ray diffraction (XRD), nitrogen (N2)-adsorption and ammonia-temperature programmed desorption (NH3-TPD) techniques are employed to investigate the porosity and acidity characteristics of original and modified HZSM-5 samples. Py-GC/MS and thermo-gravimetric analyzer (TGA) experiments are further conducted to explore the catalytic effect of modified HZSM-5 samples on biomass CFP and to verify the positive effect on coke reduction. Results show that EDTA treatment does not damage the crystal structure of HZSM-5 zeolites, but leads to a slight increase of pore volume and pore size. Meanwhile, the elimination of the strong acid peak indicates the dealumination of outer surface of HZSM-5 zeolites. Treatment time of 2 h (labeled EDTA-2H) is optimal for acid removal and hydrocarbon formation. Among all modified catalysts, EDTA-2H performs the best for deacidification and can obviously increase the yields of positive chemical compositions in pyrolysis products. Besides, EDTA modification can improve the anti-coking properties of HZSM-5 zeolites, and EDTA-2H gives rise to the lowest coke yield.