Search

Abstract: Soils in which fresh produce is grown can become contaminated with foodborne pathogens and are sometimes then abandoned or removed from production. The application of biochar has been proposed as a method of bioremediating such pathogen-contaminated soils. The objectives of the present study were to evaluate three fast-pyrolysis-generated biochars (FPBC; pyrolyzed in house at 450, 500, and 600°C in a newly designed pyrolysis reactor) and 10 United Kingdom Biochar Research Center (UKBRC) standard slow-pyrolysis biochars to determine their effects on the viability of four surrogate strains of Escherichia coli O157:H7 in soil. A previously validated biocidal FPBC that was aged for 2 years was also tested with E. coli to determine changes in antibacterial efficacy over time. Although neither the UKBRC slow-pyrolysis biochars or the 450 and 500°C FPBC from the new reactor were antimicrobial, the 600°C biochar was biocidal (P < 0.05); E. coli populations were significantly reduced at 3 and 3.5% biochar concentrations (reductions of 5.34 and 5.84 log CFU/g, respectively) compared with 0.0 to 2.0% biochar concentrations. The aged 500°C FPBC from the older reactor, which was previously validated as antimicrobial, lost efficacy after aging for 2 years. These results indicate that the biocidal activity of FPBC varies based on production temperature and/or age., (Published 2020 by the International Association for Food Protection. Not subject to U.S. Copyright.)

Highlights • Mild hydrotreating of catalytic fast pyrolysis bio-oils with varying oxygen content. • Hydrogen consumption was greatest for bio-oils with mid-level (20–25 wt%) oxygen. • Solvent effects were observed where hydrogenation rate was greater with more polar bio-oil. • Carbon yield and oxygen content from biomass depends mostly on CFP step of twostep process. Abstract 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. [ABSTRACT FROM AUTHOR]

Conducted in the presence of a zeolite catalyst such as HZSM-5, fast pyrolysis of biomass can promote the rejection of oxygen and the formation of aromatic hydrocarbons in the organic liquid products. Unfortunately, this pathway removes hydrogen from the already hydrogen deficient biomass starting material, limiting the yield of hydrocarbons and leading to coke formation which results in catalyst deactivation. Co-pyrolysis of biomass and a low cost hydrogen rich material such as waste plastic has been considered as one strategy for mitigating hydrogen-deficiency with an added benefit of disposing of waste plastics effectively. Previous work has shown an enhancement of aromatic yields when polyolefins were copyrolyzed with biomass over fresh HZSM-5, but studies on the effect of catalyst deactivation with repeated use of the catalyst are lacking. In this study, pyrolysis coupled with gas chromatography and mass spectrometry (py-GC/MS) with an external catalytic reactor was used to perform ex situ catalytic co-pyrolysis of switchgrass and polyethylene (1:1 w:w) in the presence of HZSM-5. The catalyst (∼15 mg) was exposed to ∼1 mg biomass and/or plastic in a series of 30 or 60 pulsed experiments for a cumulative feedstock to catalyst ratio of 2:1 and 4:1, respectively. Results showed that the initial rate of catalyst deactivation (up to feed:catalyst 2:1), as measured by the decrease in production of aromatic hydrocarbons, was significantly decreased, estimated at only ∼28% of the rate of deactivation that processing of switchgrass alone caused. However, over the continued use of the catalyst, up to a feed to catalyst ratio of 4:1, the rates of deactivation from the blended feedstock increased to near expected rates based on the rate of deactivation for the switchgrass and HDPE individually. [ABSTRACT FROM AUTHOR]

The study of the effects of harvest time on switchgrass ( Panicum virgatum L.) biomass and bioenergy production reported herein encompasses a large study evaluating the harvest of six switchgrass cultivars grown at three northern US locations over 3 years, harvested at upland peak crop (anthesis), post-frost, and post-winter. Delaying harvest of switchgrass until after frost and until after winter has resulted in decreased yields of switchgrass and reduced amounts of minerals in the biomass. This report examines how changes in biomass composition as a result of varying harvest time and other factors affect the distribution of products formed via fast pyrolysis. A subset (50) of the population ( n = 864) was analyzed for fast pyrolysis and catalytic pyrolysis (zeolite catalyst) product yields using a pyrolysis-GC/MS system. The subset was used to build calibrations that were successful in predicting the pyrolysis product yield using near-infrared reflectance spectroscopy (NIRS), and partial least squares predictive models were applied to the entire sample set. The pyrolysis product yield was significantly affected by the field trial location, year of harvest, cultivar, and harvest time. Delaying harvest time of the switchgrass crop led to greater production of deoxygenated aromatics improving the efficiency of the catalytic fast pyrolysis and bio-oil quality. The changes in the pyrolysis product yield were related to biomass compositional changes, and key relationships between cell wall polymers, potassium concentration in the biomass, and pyrolysis products were identified. The findings show that the loss of minerals in the biomass as harvest time is delayed combined with the greater proportion in cellulose and lignin in the biomass has significant positive influences on conversion through fast pyrolysis. [ABSTRACT FROM AUTHOR]

Metal-modified HZSM-5 catalysts were prepared by the ion exchange of NH4ZSM-5 (SiO2/Al2O3=23) using Zn, Ga, Ni, and combinations thereof. The prepared catalysts were used to evaluate catalytic pyrolysis for the conversion of Eucalyptus urophylla to fuels and chemicals, specifically aromatic hydrocarbons, by using a micro-scale pyrolysis reactor coupled with GC-MS. Two different biomass-to-catalyst ratios (1:5 and 1:10 w/ w) were studied. The catalyst prepared with Ga by total ion exchange (Ga-HZSM-5 B, ≈7 wt % Ga) yielded the highest amount of aromatic hydrocarbons, whereas the catalysts modified with Ni produced the lowest yield of aromatic hydrocarbons. A correlation between the methane yield and benzene and p-xylene selectivity was found for the catalysts, which was observed mainly for the Ni-, Zn-, and Ga-Ni-modified catalysts. The Ga-modified catalysts were the most selective for xylenes, whereas the Ni-based catalysts were the most selective for benzene production with a concurrent increase in methane production. The Zn-modified catalysts were the most selective for toluene production. [ABSTRACT FROM AUTHOR]

As a dedicated bioenergy crop, switchgrass is a potential feedstock within the United States for biofuels production. It can be converted to energy dense bio-oil through fast pyrolysis. Biomass compositional differences can influence the conversion efficiency and bio-oil product yield and quality. In order to understand how improvements in bio-oil quality can be achieved by manipulation of biomass composition, differences in switchgrass biomass composition were evaluated for their impacts on fast pyrolysis product yield. Nine genotypes of switchgrass were grown on one prime and two marginal sites in New Jersey. The results show that biomass composition was affected by genotype, the environment, and genotype × environment interactions. Non-catalytic pyrolysis product yields were largely affected by genotypic differences. The most significant impacts on non-catalytic pyrolysis products were from cellulose content and K content in the biomass. It was found that non-methoxylated phenolics were mainly produced from the breakdown of levoglucosan in the presence of K. Mineral content in the biomass was highly variable by environment and soil variability across the sites examined. These differences in mineral content largely impacted product distribution of HZSM-5-catalyzed pyrolysis, showing that lower mineral uptake in the biomass was beneficial for the production of aromatic hydrocarbons. Significant genotypic and environmental effects among the pyrolysis products demonstrate that breeding for improvements in pyrolysis product yield is conceivable but that growing conditions and soil conditions must also be taken into consideration. [ABSTRACT FROM AUTHOR]

Guayule ( Parthenium argentatum ) is a woody desert shrub cultivated in the southwestern United States as a source of natural rubber, organic resins, and high energy biofuel feedstock from crop residues. We used guayule bagasse, the residual biomass after latex extraction as feedstock in a pyrolysis process that employs a reactive gas environment to formulate a special intermediate bio-oil product that allows use of conventional hydrotreating with conventional noble metal catalysts and a simple distillation process to synthesize hydrocarbon (drop-in) fuels. The said guayule-bagasse tail gas reactive pyrolysis (TGRP) process comprises pyrolyzing the guayule bagasse in a fluidized-bed reactor in the presence of a reactive and flammable tail gas (comprising CO ∼ 30%, CH 4 ∼ 16%, CO 2 ∼ 40%, H 2 ∼ 10%, C 2 H 4 ∼ traces) generated in the pyrolysis process and without the use of catalyst to produce bio-oil with C/O molar ratio of 14/1 in organic yields of 34–40 wt% having an energy content of 31–37.5 MJ/kg. When we further processed the said bio-oil by centrifugation, we obtained 85 wt% yield and further 50–65 wt% yields following a continuous hydrotreatment over common noble metals (Pt, Ru or Pd) on a carbon support. Distillation of this mixture yielded >95 wt% hydrocarbon liquid fuel mixture comprising 30.4% gasoline (C 5 –C 7 ), 37% jet (C 8 –C 12 ) and 24% diesel (C 13 –C 22 ). Analysis of a composite mixture of the hydrotreated product from the bagasse showed the majority of the sample (66%) was C 12 and below, which falls within the gasoline (naphtha) range with the greatest fraction of naphtha falling within the C 8 –C 10 range. Beyond C 12 , the molecular weights increased through the diesel range (34%), with C 37 being the highest observable molecular weight. The product met several ASTM standards for drop-in fuels, but the sulfur content (primarily due to latex extraction additives) was relatively high at around 300 ppm, indicating that hydrodesulfurization may be required to be infrastructure ready. [ABSTRACT FROM AUTHOR]

Pyrolysisof mixtures of agricultural plastic waste in the formof polyethylene hay bale covers (PE) (4–37%) and switchgrasswere investigated using the US Department of Agriculture’stail gas reactive pyrolysis (TGRP) process at different temperatures(400–570 °C). TGRP of switchgrass and plastic mixturessignificantly reduced the formation of waxy solids that are producedduring regular pyrolysis. Under an atmosphere of approximately 70%recycled tail gas, mostly noncondensable gases were produced alongwith highly deoxygenated and aromaticized pyrolysis oil. When theatmosphere was diluted further to a recycled tail gas concentrationof about 55%, higher yields of liquid product were achieved but withless deoxygenation. TGRP of low plastic mixtures (4–8%) producedoils with increased carbon and reduced oxygen content compared tothe fast pyrolysis of switchgrass alone. Noncondensable gas fractionscontaining high concentrations of H2, CO, ethylene, andother light hydrocarbons remained a significant portion of the productmixture at temperatures above 500 °C. [ABSTRACT FROM AUTHOR]

A typical petroleum refinery makes use of vacuum gas oil by cracking the large molecular weight compounds into light fuel hydrocarbons. For various types of fast pyrolysis bio-oil, successful analogous methods for processing heavy fractions could expedite integration into a petroleum refinery for fuel production. This paper investigated the applicability of bio-oil distillation residues (i.e., ‘bottoms’) toward end-use and/or post-processing through the use of various physical and chemical characterization methods, including FTIR, NMR and their decomposition in a micropyrolyzer (Py–GC–MS). We compared distillate bottoms from both the recently developed tail-gas reactive pyrolysis (TGRP) and traditional pyrolysis bio-oils, emanating from switchgrass and horse manure feedstocks. Based on the FTIR and NMR measurements, we found the traditional bio-oil bottoms to contain more reactive functional groups, whereas TGRP bottoms are highly aromatic and exhibit a lack of functional groups. Manure-based bottoms consistently contained more aliphatic carbons than those of switchgrass origin. However, irrespective of the origin of the feedstock, all bottoms samples possessed high HHVs making them suitable for solid fuel application, such as direct combustion (30 MJ/kg for traditional bio-oil bottoms; 37 MJ/kg for TGRP bottoms). A preliminary evaluation using Py–GC–MS to test their suitability for use in refinery cracking processes revealed that the TGRP-based bottoms all produced significant yields of pyrolyzate (20–50%), with nearly all detected compounds comprising alkyl benzenes and alkyl phenols. However, the manure-based TGRP bottoms produced a higher proportion of C 8 –C 18 paraffin compounds. [ABSTRACT FROM AUTHOR]

Fast pyrolysis is becoming a more attractive conversion option for the production of biofuels, due to the potential for directly producing hydrocarbon fuels seamlessly compatible with petroleum products (drop-in fuels). Dedicated bioenergy crops, like perennial grasses and short-rotation woody crops, will be among the major sources of biomass for fast pyrolysis. To aid in the advancement of fast pyrolysis conversion and to identify appropriate feedstock crops, novel genotypes of shrub willow recently bred for high yield were evaluated for pyrolysis product yield using pyrolysis-gas chromatography-mass spectroscopy (py-GC/MS). The goal of this study was to understand how variations in biomass composition impact pyrolysis conversion efficiency and pyrolysis oil (bio-oil) quality by analyzing the composition of the pyrolysis vapors by py-GC/MS. The results of the py-GC/MS analysis showed significant differences in products from both non-catalytic and catalytic pyrolysis carried out over zeolite catalyst (HZSM-5), which were correlated with differences in biomass composition. For non-catalytic conversion, the most significant relationships were between the syringyl:guaiacyl (S:G) ratio in the biomass and phenolic monomers, in addition to levoglucosan yields and cellulose content. Production of phenols, guaiacols, and syringols were largely independent of total lignin content, but were strongly related to the S:G ratio. Willow genotypes with low ash content and high cellulose content produced more liquid products and higher levels of deoxygenated aromatics following catalytic pyrolysis. These results demonstrate that it is possible to breed for improvements in biomass compositional traits that can ultimately lead to improvements in bio-oil yield and quality. [ABSTRACT FROM AUTHOR]

Catalytic pyrolysis over HZSM-5 is an effective method for the conversion of biomass to aromatic hydrocarbons, albeit with low yield and short catalyst lifetimes. Addition of co-reactants rich in carbon and hydrogen can enhance yield and possibly increase catalyst lifetimes by reducing coke formation. Particularly, the catalytic co-pyrolysis of plastic and biomass has been shown to enhance conversion to aromatic hydrocarbons, and also offers a method for productive disposal of waste agricultural plastics. In an effort to determine the origin of the carbon (plastic or biomass) in the products from this catalytic co-pyrolysis, mixtures of uniformly labeled 13 C cellulose and non-labeled plastic including polyethylene terephthalate, polypropylene, high density polyethylene, low density polyethylene and polystyrene were subjected to catalytic fast pyrolysis (CFP) at 650 °C in the presence of HZSM-5. A micro pyrolyzer coupled with GC/MS (py-GC/MS) advised product distributions and mass spectral data was used to determine the distribution of biogenic carbon and plastic derived carbon in the products. The results demonstrate that aromatic hydrocarbon products formed from the CFP of mixtures of cellulose and plastic are composed mostly of molecules containing carbon of mixed origin. Data on the distribution of 13 C x 12 C y from the products followed in this study show that polyolefin mixtures with cellulose favor the formation of alkyl benzenes that incorporate carbon from both sources. Utilization of aromatic polymers (polystyrene or polyethylene terephthalate) is more selective for formation of naphthalenes with carbon derived from both products. The distribution of various 13 C x 12 C y products is used to suggest active mechanisms that result in the formation of the observed products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Distillate residues from biomass pyrolysis oils were synthesized into renewable pitch. • The biopitch properties closely align with those of coal tar pitch. • Diverse biomasses used allow greater flexibility for biorefineries. Petroleum-based carbon solid materials, such as petcoke and coal tar pitch, have decreased in quality and/or availability due to various factors, such as the declining elemental quality of crude oil and the push towards environmental sustainability. Coal tar pitch acts as a binder in smelting anodes for aluminum production, which contributes significantly to the fossil-based CO 2 production globally. In an effort to reduce the carbon footprint of these processes, we synthesized a renewable biopitch based on biomass pyrolysis. In comparison to previous studies on biopitch, we utilized pyrolysis bio-oils with reduced oxygen content (<15%). Guayule and switchgrass biomasses served as the biomass of choice, and their bio-oils underwent continuous distillation. Solid residues underwent extraction to remove toluene insolubles (TI), and the remaining fraction underwent heat treatment to ∼ 380 °C. While both the residues and biopitches contained trace amounts of quinoline insolubles (QI), the pitch TI amounted to 32 – 54 wt%. Coking values exceeded 43 wt% for both pitches, making them feasible for anode utilization. The use of distilled partially deoxygenated oils enables greater flexibility for biorefineries to provide a marketable coproduct alongside hydrocarbon fuels. [ABSTRACT FROM AUTHOR]

Two Brazilian biomass samples, namely sugarcane trash and Eucalyptus benthamii were evaluated as feedstocks for liquid and solid fuels production by fast pyrolysis, using a fluidized bed reactor and two different sets of process conditions. In the first, an inert gas (N2) was used as a fluidizing agent while in the second, a mixture of N2 and recycled pyrolysis effluent gas, mainly CO, CO2, H2 and light hydrocarbons, was used as the fluidizing agent and to also create a reducing reaction atmosphere for the process. Comparing both processes, the reducing atmosphere had a significant deoxygenation effect on the pyrolysis oil from the two feedstocks, improving the quality and stability of the oils by reducing water, total acid number (TAN), viscosity, and increasing the higher heating value (HHV). For both feedstocks, reduced amounts of acetic acid, acetol and levoglucosan, and increased amounts of aromatic hydrocarbons not initially present in the traditional bio-oil were observed for the organic fraction of the bio-oil. However, there was a reduction of 13.5wt% (db) in the bio-oil yield from E. benthamii when a reactive atmosphere was used. Comparing both feedstocks, the eucalyptus yielded on the average, 50% more bio-oil than the sugarcane trash while the trash yielded 50% more permanent gas. Apart from the high ash content associated with biochar from sugarcane trash, biochar produced from both feedstock samples had similarities with bituminous coal in terms of moisture content, fixed carbon content, and heating values. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we sought to elucidate the relationships between biomass feedstock type and the suitability of their fast-pyrolysis bio-oils for hydrodeoxygenation (HDO) upgrading. Switchgrass, Eucalyptus benthamii, and equine manure feedstocks were pyrolyzed into bio-oil using a continuous fast-pyrolysis system. We also synthesized variations of switchgrass bio-oil using catalytic pyrolysis methods (HZSM-5 catalyst or tail-gas recycle method). Bio-oil samples underwent batch HDO reactions at 320°C under ~2100psi H2 atmosphere for 4h, using Pt, Ru, or Pd on carbon supports. Hydrogen consumption was measured and correlated with compositional trends. The resulting organic, aqueous, and gas phases were analyzed for their chemical compositions. Mass balances indicate little coke formation. Switchgrass bio-oil over Pt/C performed the best in terms of hydrogen consumption efficiency, deoxygenation efficiency, and types of upgraded bio-oil compounds. Eucalyptus feedstocks consistently consumed more than twice the normal amount of hydrogen gas per run, primarily due to the elevated syringol content. Catalytically pyrolyzed bio-oils deoxygenated poorly over Pt/C but hydrogenated more extensively than other oils. Although the relative deoxygenation (%DOrel) varied based on feedstock and catalyst, the absolute deoxygenation (%DOabs) depended only on the overall yield. The total extent of upgrading (hydrogenation+deoxygenation) remained independent of feedstock and catalyst. [Copyright &y& Elsevier]

Highlights: [•] Switchgrass and polyhydroxybutyrate (P3HB) were co-pyrolyzed. [•] Switchgrass pyrolysis oil, bio-char and crotonic acid were produced at 375°C. [•] Maximum crotonic acid yield was about 45% of input P3HB. [•] Crotonic acid may be present as both gas and aerosol in the pyrolysis vapor stream. [ABSTRACT FROM AUTHOR]

Thefate of inorganic species present in switchgrass during fluidizedbed catalytic pyrolysis over HZSM-5 catalysts was studied with emphasison their accumulation on the catalyst. Five catalytic pyrolysis experimentswere performed in two series, reusing the catalyst after each sample.Catalysts were regenerated from deactivation due to carbon depositsvia their removal by combustion at regular intervals. The fates ofseven inorganic elements were tracked: Ca, Cu, Fe, K, Mg, Na, andP. Potassium accumulated with the HZSM-5 catalyst the fastest whileiron was the metal that accumulated most preferentially on the catalysts,with about 42% of the Fe content of the biomass remaining with theHZSM-5. The total amount of these seven elements accumulated on HZSM-5in a linear fashion during continued use of the same catalyst sample.As the catalyst was exposed to more switchgrass and accumulated moreinorganic containments, its effectiveness at deoxygenating the pyrolysisliquids decreased. Selectivity for aromatic hydrocarbons also decreased,indicating that deactivation of HZSM-5 by exposure to inorganic contaminantsin biomass should be a consideration for biomass deoxygenation bycatalytic fast pyrolysis. [ABSTRACT FROM AUTHOR]

Biochars produced from thermochemical conversions of biomass were evaluated by temperature programmed oxidation (TPO). This technique, used to characterize carbon deposits on petroleum cracking catalysts, provides information on the oxidative stability of carbonaceous solids, where higher temperature reactivity indicates greater structural order, an important property for biochar applications. Differences between TPO profiles of biochars generated by fast pyrolysis of soy straw, barley straw, switchgrass, bamboo, and various woods demonstrated that the oxidative stabilities of the biochars are dependent on the starting biomass. Biochars from softwood and hardwood feedstocks were also processed by torrefaction and gasification to assess the impact of the thermoprocessing method on the TPO data. Results from these TPO analyses showed that the biochars produced under higher temperature conditions afford biochars that are more oxidation resistant. Biochars produced from pine wood (softwood) were consistently more resistant to oxidation compared to their hardwood counterparts. This exploratory study represents the first application of TPO to biochars. [ABSTRACT FROM AUTHOR]

Highlights: [•] Oil seed presscakes are a source of proteinaceous biomass. [•] Stable pyrolysis oils are produced from pennycress presscake. [•] Hydrotreating over Ru/C and Pd/C reduced oxygen content of bio-oils. [•] Upgraded products were characterized by GC×GC and NMR. [•] Upgraded bio-oil from presscake contained fewer heteroatoms than that from wood. [ABSTRACT FROM AUTHOR]

Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture (USDA). USDA is an equal opportunity provider and employer. Mass, energy, and exergy balances are analyzed for bio-oil production in a bench-scale fast pyrolysis system developed by the USDA's Agricultural Research Service (ARS) for the processing of commodity crops to fuel intermediates. Because mass balance closure is difficult to achieve due, in part, to the system's small size and complexity a linear programming optimization model is developed to improve closure of elemental balances without losing the overall representation of the pyrolysis products. The model results provide an opportunity to analyze true energy and exergy balances for the system. While energy comparisons are based on heating values, exergy flows are computed using statistical relationships and other standard techniques. Comparisons were made for a variety of biomass feedstocks including energy crops and various byproducts of agriculture and bioenergy industry. The mass model allows for proper accounting of sources of mass loss and suggestions for improved system performance. Energy recovery and exergetic efficiency are compared for a variety of pyrolysis product utilization scenarios including use of biochar and noncondensable gases as heat sources. Exergetic efficiencies show high potential for energy utilization when all the pyrolysis product streams can be recycled to recuperate their internal energy. The exergy analysis can be beneficial to developing exergetic life cycle assessments (ELCA) for the fast pyrolysis process as sustainable technology for advanced biofuels production. [ABSTRACT FROM AUTHOR]

Fast pyrolysis of lignocellulosic biomass is a facile method for producing high yields of liquid fuel intermediates. However, because most fast pyrolysis oils are highly oxygenated, acidic, and unstable, identification of feedstocks that produce higher quality pyrolysis liquids is desirable. Therefore, the effect of feedstock protein content was studied by performing fast pyrolysis experiments on biomass with varying protein content. The feedstocks ranged from low-protein content, ∼5% up to feedstocks with >40 wt.% protein content. Protein content was not a major factor in the yield of pyrolysis oil or the distribution of biomass carbon into the pyrolysis products. However, elevated levels of protein did cause a deoxygenation effect in the pyrolysis process with more of the oxygen rejected from the biomass as water. The deoxygenation caused the pyrolysis oil from the higher protein containing biomass to have higher energy content. Furthermore, the concentration of basic nitrogen groups caused the pyrolysis oil from the higher protein biomass to shift to a more neutral pH and lower total acid number than has been measured typically for lignocelluloic biomass pyrolysis oils. Some of the pyrolysis oils, particularly those from the mustard seed family presscakes exhibited better thermal stability than low-protein pyrolysis oils. [ABSTRACT FROM AUTHOR]

Abstract: Zeolites have been shown to effectively promote cracking reactions during pyrolysis resulting in highly deoxygenated and hydrocarbon-rich compounds and stable pyrolysis oil product. Py/GC–MS was employed to study the catalytic fast pyrolysis of lignocellulosic biomass samples comprising oak, corn cob, corn stover, and switchgrass, as well as the fractional components of biomass, i.e., cellulose, hemicellulose, and lignin. Quantitative values of condensable vapors and relative compositions of the pyrolytic products including non-condensable gases (NCG''s) and solid residues are presented to show how reaction products are affected by catalyst choice. While all catalysts decreased the oxygen-containing products in the condensable vapors, H-ZSM-5 was most effective at producing aromatic hydrocarbons from the pyrolytic vapors. We demonstrated how the Si/Al ratio of the catalysts plays a role in the deoxygenation of the vapors towards the pathway to aromatic hydrocarbons. [Copyright &y& Elsevier]

Abstract: A solid water insoluble material (WIS), commonly called pyrolytic lignin, can be isolated from biomass fast pyrolysis oils. Such material was isolated from the bio-oils produced from barley straw, barley hulls, switchgrass, soy straw and oak and then fully characterized. Analytical techniques employed in the characterization included elemental analysis, pyrolysis-GC/MS, Nuclear Magnetic Resonance Spectroscopy (NMR) and Gel Permeation Chromatography (GPC). The characterization showed that the materials were mostly but not entirely derived from the lignin fraction of the biomass; they were largely made up of aromatic rings, substituted with varying amounts of methoxy groups and linked by varying types of aliphatic linkers. The NMR identified different types of aliphatic linkers in the isolates, some previously reported and some newly proposed. GPC analysis showed that the dimers and trimers were the most common oligomeric size though units comprising a wide variety of molecular weights, some >1500Da, were detected. [Copyright &y& Elsevier]

Abstract: Lignin from four different sources, extracted by various methods, were pyrolyzed at 650°C using analytical pyrolysis methods (Py-GC/MS). Pyrolysis was carried out in the absence and presence of two heterogeneous catalysts, an acidic zeolite (HZSM-5) catalyst and a mixed metal oxide catalyst (CoO/MoO3). Non-catalytic Py-GC/MS was used to identify the lignin as characterized by their H-, G- or S-lignin makeup and also served as the control basis to evaluate the effect of the said catalysts on the production of aromatic hydrocarbons from these lignin sources. Experiments show that the selectivity to particular aromatic hydrocarbons varies with the composition of the lignin for both catalysts. The major pathway for hydrocarbon production over HZSM-5 is likely increased depolymerization efficiency that releases and converts the aliphatic linkers of lignin to olefins followed by aromatization. Simple phenols produced from the deconstruction of the lignin polymer are likely to be a source of zeolite deactivation. The CoO/MoO3 is likely to produce aromatic hydrocarbons through a direct deoxygenation of methoxyphenol units. [ABSTRACT FROM AUTHOR]

The article discusses research investigating the sustainable production of bioenergy and biochar from the straw of high-biomass soybean lines using fast pyrolysis. The team used two high-biomass soybean lines, which were developed at the U.S. Agricultural Research Service (ARS) for bioenergy, and subjected them to thermochemical conversion via fast pyrolysis. The objective of the study was the evaluation of the potential use of straw for the production of liquid fuel intermediates, such as pyrolysis liquid. Topics include an overview of the potential use of pyrolysis liquid, the concept of on-farm biorefineries in a soybean farm system, and the use of biochar as a soil amendment.

Abstract: Economic and sustainable biofuel production requires high process efficiency. The choice of biomass and the conversion technology employed to produce renewable fuels determine the product yields, fuel quality and consequently the process efficiency. Guayule, a perennial shrub native to the southwestern United States, is currently cultivated as a source of natural rubber latex. However, after latex extraction, about 90% of the crop is used for low value biomass markets or simply goes to waste. Residual biomass from guayule presents an opportunity as a solid fuel resource that is already collected, on-site, and is a suitable ligno-cellulosic conversion feedstock. Using Py–GC/MS, we characterized the starting material of whole guayule shrub (G1) and solid waste streams, including ground bagasse from the industrial latex extraction process (G4), ground whole shrub minus resin (G2), and ground whole shrub minus resin and rubber (G3). These waste streams contain varying amounts of resin and rubber compounds. We measured the energy content of these streams and compared their compositions based on Py–GC/MS pyrograms. Catalytic and non-catalytic pyrolysis reactions were performed. It was found that the stem-derived latex-extracted guayule bagasse (G4) is the material with the most thermochemical energy potential. Whole shrub (G1) is the next in energy content. The gross energy content declined as resin is removed (G2) and further declined with the removal of resin and rubber (G3). The pyrograms showed fragmentation of the biomass polysaccharides and lignin polymers to compounds that have chemical energy, which provides support to the gross energy profiles. [Copyright &y& Elsevier]

Abstract: Bio-oil and bio-char were produced from corn cobs and corn stover (stalks, leaves and husks) by fast pyrolysis using a pilot scale fluidized bed reactor. Yields of 60% (mass/mass) bio-oil (high heating values are ∼20MJkg−1, and densities >1.0Mgm−3) were realized from both corn cobs and from corn stover. The high energy density of bio-oil, ∼20–32 times on a per unit volume basis over the raw corn residues, offers potentially significant savings in transportation costs particularly for a distributed “farm scale” bio-refinery system. Bio-char yield was 18.9% and 17.0% (mass/mass) from corn cobs and corn stover, respectively. Deploying the bio-char co-product, which contains most of the nutrient minerals from the corn residues, as well as a significant amount of carbon, to the land can enhance soil quality, sequester carbon, and alleviate environmental problems associated with removal of crop residues from fields. [Copyright &y& Elsevier]

Abstract: Guayule is a perennial shrub grown in the southwestern United States that is used to produce high quality, natural rubber latex. However, only about 10% of the plant material is used for latex production; the remaining biomass, called bagasse, can be used for renewable fuel production. Fast pyrolysis of guayule, both whole shrub and bagasse was performed. From both feedstocks a very viscous, high energy content (∼30MJ/kg) pyrolysis liquid (bio-oil) was produced in yields averaging over 60% without any catalyst. The properties and compositions of the bio-oils were found to be similar in the two feedstocks. Co-products, charcoal (20–30wt%) and non-condensable gas (5–15%), were also dense and had a high energy content. Of the two feedstocks, the whole shrub yielded higher quantities of charcoal that also had a higher energy content than the charcoal produced from bagasse. As a result, the energy recovery, estimated as the percentage of the energy products, to energy input into the reactor was lower (60%) for guayule bagasse than for the whole shrub (73%). This notwithstanding, the bagasse is a more attractive feedstock for thermochemical conversion, not only because it is a residue from a primary process (latex extraction) that is on-site, but also because it has a high energy content. Moreover, it produces high quality pyrolysis products. Co-production of latex rubber from the whole shrub and renewable fuels from the residual bagasse by pyrolysis should improve the already positive economics of the guayule latex rubber industry. [Copyright &y& Elsevier]

• Six guayule genotypes grown under different irrigation levels were evaluated for bio-oil byproducts. • Variations in pyrolysis byproducts due to genotypes and irrigation levels were observed. • Positive correlations among bio-oils suggest the possibility to improve byproducts in future guayule breeding program. In addition to the commonly known use as an alternative source for natural rubber and hypoallergenic latex, guayule could also be a source of resin and bagasse for use in the pharmaceutical and biofuel industries. Pyrolysis is a method to convert guayule biomass into liquid (condensable gas or bio-oil), which can be an intermediate towards production of biofuels and/or renewable chemicals. In this work, six guayule genotypes that were planted under either well-irrigated or reduced-irrigation conditions were pyrolyzed using a pyrolysis gas-chromatography-mass spectrometry instrument (PY-GC/MS). The products included condensable gas, non-condensable gas and bio-char. Within the condensable gases, selected compounds were divided into nine chemical classes including aromatic hydrocarbons, alkyl phenols, guaiacols, syringols, furans, cyclopentenones, acetic acid and acetol, levoglucosan and limonene groups. As a result, significant variations were observed in the major compounds and prominent sub-constituents of condensable gas among the studied guayule genotypes and under irrigation levels. Strong positive correlations were found between irrigation levels and oxygenated condensable gas components derived from cellulose and lignin, although hydrocarbon components derived from the rubber and resin were found to be negatively correlated with irrigation levels. Results indicated that the genetic variations among guayule genotypes can be used to improve its bioenergy potential, and positive correlations observed among pyrolysis byproducts suggest the possibility to improve several byproducts simultaneously in guayule breeding programs. This research gives an insight to breed for guayule as an economic crop with high bioenergy potential for the development of sustainable agriculture. [ABSTRACT FROM AUTHOR]

Kraft lignin (Indulin AT) pretreated with magnesium formate and magnesium hydroxide was fast-pyrolyzed in a continuously fed, bench-scale system. To avoid fouling issues typically associated with lignin pyrolysis, a simple laboratory test was used to determine suitable ranges of magnesium hydroxide and formic acid to lignin for feeding without plugging problems. Various feedstock formulations of lignin pretreated with magnesium hydroxide and formic acid were pyrolyzed. For comparison, calcium formate pretreated lignin was also tested. The organic oil yield ranged from 9% to 17% wt % on a lignin basis. Carbon yields in the oil ranged from 10% to 18% wt % on a lignin basis. Magnesium formate pretreatment increased oil yield and carbon yield in the oil up to 35% relative to the higher 1:1 g magnesium hydroxide/g lignin pretreatment. However, a lower magnesium hydroxide pretreatment (0.5:1 g magnesium hydroxide/g lignin) resulted in oil yields and carbon yields in the oils similar to the magnesium formate pretreatments. Magnesium formate pretreatment produced more oil but with a higher oxygen content than calcium formate under the same conditions. The GC-MS analysis of product oils indicated that phenols and aromatics were more prevalent in pyrolyzed magnesium-formate-pretreated lignin. [ABSTRACT FROM AUTHOR]

Highlights • A mobile fast pyrolysis demonstration unit was designed, constructed and operated. • Design is based on dual fluid bed Combustion Reduction Integrated Pyrolysis System. • Bio-oil yields of ∼45 wt% from of switchgrass, woody biomass and horse manure. • Catalytic pyrolysis over HZSM-5 produced bio-oil with <10 wt% oxygen. • Continuous regeneration of zeolite from coke deposits was demonstrated. Abstract A mobile pyrolysis unit, designed to process biomass at a rate of 83.3 kg h−1 (two metric tons per day, MTPD) has been developed, constructed and its operation demonstrated for on-farm or in-forest production of pyrolysis oil (bio-oil). The trailer-mounted pyrolysis apparatus is based on the combustion reduction integrated pyrolysis system (CRIPS), a patented, dual fluidized bed, biomass pyrolysis design developed by USDA and the University of Pretoria. The mobile design goal was to demonstrate efficacy of on-farm production and coordinate station-to-station operation to simulate a collective system of several unit operations within a distributed/satellite system of pyrolysis biorefinery. Key design features that provide utility for remote operations including in-situ (on-trailer) generation of heat and electric power required for self-sufficiency were tested at this scale. Extensive trials on three feedstocks important to US agriculture, namely woody biomass, switchgrass and horse litter, were conducted. The results show that a processing rate of up to 40 kg h−1 (approximately 1 MTPD) was successful and easily achievable for the said biomass on the trailer; however, beyond this rate operational problems such as pressure imbalances between the dual-bed reactors were encountered, hampering process control. The operation of the CRIPS under catalytic pyrolysis conditions was also successful with catalyst regeneration readily achievable with the design. Bio-oil yield for neat/traditional and catalytic pyrolysis were in the 45% and 5–10% ranges respectively, similar to lab scale, demonstrating production of large volumes of bio-oil on-farm. Bio-oil quality for catalytic pyrolysis was consistent over several hours on stream due to continuous catalyst regeneration that the design affords yielding high levels of BTEX compounds; however, deactivation due to alkali contamination was noticeable at cumulative biomass to catalyst ratios of > 6/1. Compared with laboratory scale results, non-catalytic pyrolysis product quality for the demonstration scale wavered between that of regular pyrolysis oil produced under nitrogen atmosphere and that of the tail-gas reactive pyrolysis (TGRP) as partial recycle of effluent gas was possible with the mounted CRIPS design. With successful demonstration at 1 MTPD capacity the mobile system meets the technology readiness level for pre-commercial design suggested for blueprints (i.e. development of full-scale prototype), however more testing is underway to remove the bottlenecks impeding operation at the full-scale design. [ABSTRACT FROM AUTHOR]

In this study, we tested the effect of hot water extraction (HWE) as a biomass pretreatment on the pyrolysis of three cultivars of shrub willow via both conventional heating (using a micropyrolyzer, Py-GC/MS) and microwave-assisted heating (using a laboratory scale microwave reactor and activated charcoal as an added microwave absorber). The py-GC/MS experiments revealed that there was little difference in pyrolysis behavior among the cultivars for raw or HWE pretreated samples. Using either heating method, pyrolysis of the HWE pretreated samples produced less acetic acid and CO 2 than did the untreated biomass; conversely there was an increase in levoglucosan yield with HWE pretreatment. The difference in levoglucosan yield was particularly large (4 fold increase) for the py-GC/MS experiments and was attributable in large part to the demineralization of the HWE samples. The decreased mineral content appeared to have a larger effect on conventional heating than in the microwave assisted heating. The pyrolysis of HWE pretreated biomass also led to more rapid temperature increases during microwave-assisted pyrolysis performed at 1000 W. Therefore the microwave-assisted pyrolysis of HWE was studied at two different microwave power settings to compare the effect of HWE on both processes at similar temperatures. At similar temperature conditions the yield of bio-oil, bio-char and non-condensable gases from microwave-assisted pyrolysis were similar between the pretreated and raw willow but the bio-oil contained higher concentrations of aromatic hydrocarbons and less acetic acid and levoglucosan. Overall, the HWE pretreatment had a greater effect on bio-oil composition than bio-oil yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phenolics were extracted from catalytic fast pyrolysis bio-oils. • Spinning band distillation purified phenol from catalytic pyrolysis bio-oil phenolics. • This is the first known isolation of single compound phenol from bio-oil to greater than 92 wt% • The hydrocarbon fraction of said bio-oils was made into biobased pitch solid. Competitive pricing for biofuels will require the coproduction of biobased products and chemicals to improve the economic outlook of biorefineries. Phenolics have been eyed due to their natural abundance in bio-oils relative to petroleum, as well as their potential profit margins. In bio-oils, the wide product distribution (especially phenolics) prevents meaningful separation. We've shown previously that bio-oils with relatively low oxygen (<15 wt%) from advanced pyrolysis processes can be distilled and/or extracted, producing a fraction rich in phenol and cresols. To further improve separation, we utilized a spinning band column distillation system, designed to perform at 200 theoretical plates. Catalytic (HZSM-5) pyrolysis bio-oils from switchgrass biomass first underwent extraction directly, producing a phenolic fraction and a hydrocarbon fraction. Subsequently, the phenolic fraction underwent a preliminary flash distillation ahead of spinning band distillation, in order to remove residues. Spinning band distillation resulted in fractions with more than 80 wt% phenol (the balance o-cresol), which can be purified by recrystallization in pentane. Both GC/MS and NMR indicate phenol crystals were obtained at ∼92 wt% purity. To complete the biorefinery concept, the hydrocarbon fraction was distilled to obtain a fuel product and heavy polyaromatic residues. The residues were thermally treated to produce bio-pitch. [ABSTRACT FROM AUTHOR]

Guayule ( Parthenium argentatum ), a woody desert shrub cultivated in the southwestern United States, is a source of natural rubber and organic resins that promises to revolutionize the tire and rubber industry. Some 20,000 kg ha −1 yr −1 is reported to be harvested worldwide and expected to grow due to renewed interest in guayule to replace imported Hevea rubber. We have recently reported the use of guayule bagasse, the residual biomass after latex extraction, as feedstock in a pyrolysis process that employs a reactive gas environment to formulate a special intermediate bio-oil product that is easily distillable and readily synthesized to hydrocarbon (drop-in) fuels (Boateng et al., 2015). This submission reports on the use of the same pyrolysis process for the leaves of the guayule plant and the array of fuels and chemicals that the leaves can contribute to a co-located guayule biorefinery at a latex plant that could utilize the entire biomass residue value chain. The composition of the guayule leaves is different from the bagasse, with the main differences being lower resin content along with higher ash (>16 wt%) and higher nitrogen (2.6 wt%, dry ash free, daf) contents resulting from the higher concentration of the plant proteins (16.4 wt% (daf)). Since the former two components have exhibited a drastic influence on pyrolysis product distribution in the past, it was incumbent upon us to explore whether the resin content would provide additional synergistic effects and influence product selectivity pathways to bio-based chemicals. We found that the combined effect of the tail gas reactive pyrolysis process, the proteinaceous nature of the guayule leaf and resin combine to create a complex mechanism that results in an interesting bio-oil intermediate product from which a slew of fuel and commodity chemical compounds can be synthesized upon mild upgrading. [ABSTRACT FROM AUTHOR]

Herbaceous bioenergy crops, including sorghum, switchgrass, and miscanthus, were evaluated for their potential as phytoremediators for the uptake of phosphorus in the Delmarva Peninsula and their subsequent conversion to biofuel intermediates (bio-oil) by fast pyrolysis using pyrolysis-gas chromatography/mass spectroscopy. Four cultivars of sorghum, five cultivars of switchgrass and one miscanthus ( Miscanthus × giganteus ) were grown in soils with two different levels of poultry manure (PM) applications. Little variation was seen in phosphorus uptake in the two different soils indicating that the levels of available phosphorus in the soil already saturated the uptake ability of the plants. However, all plants regardless of trial took up more phosphorus than that measured for the non- PM treated control. Sorghum accumulated greater levels of nutrients including phosphorus and potassium compared to switchgrass and miscanthus. The levels of these nutrients in the biomass did not have an effect on carbohydrate contents. However, the potential yield and composition of bio-oil from fast pyrolysis were affected by both agronomics and differences in mineral concentrations. [ABSTRACT FROM AUTHOR]

Aspen Plus® based simulation models have been developed to design a pyrolysis process for on-site production and utilization of pyrolysis oil from equine waste at the Equine Rehabilitation Center at Morrisville State College (MSC). The results indicate that utilization of all the available waste from the site's 41 horses requires a 6 oven dry metric ton per day (ODMTPD) pyrolysis system but it will require a 15 ODMTPD system for waste generated by an additional 150 horses at the expanded area including the College and its vicinity. For this a dual fluidized bed combustion reduction integrated pyrolysis system (CRIPS) developed at USDA's Agricultural Research Service (ARS) was identified as the technology of choice for pyrolysis oil production. The Aspen Plus® model was further used to consider the combustion of the produced pyrolysis oil (bio-oil) in the existing boilers that generate hot water for space heating at the Equine Center. The model results show the potential for both the equine facility and the College to displace diesel fuel (fossil) with renewable pyrolysis oil and alleviate a costly waste disposal problem. We predict that all the heat required to operate the pyrolyzer could be supplied by non-condensable gas and about 40% of the biochar co-produced with bio-oil. Techno-economic Analysis shows neither design is economical at current market conditions; however the 15 ODMTPD CRIPS design would break even when diesel prices reach $11.40/gal. This can be further improved to $7.50/gal if the design capacity is maintained at 6 ODMTPD but operated at 4950 h per annum. [Copyright &y& Elsevier]

Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 °C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 °C in a 5 kg/h bench-scale fast pyrolysis reactor system downstream from the cyclone separator. The placement of the fixed-bed column was varied within the condenser train to determine the effect of temperature, residual water, solids, and oxygenated components of the approach vapor stream on the upgraded product quality. The upgraded liquid was collected by immediate contact with a dry ice acetone bath, complimented by a secondary collection system comprised of a methanol spray condenser. Quantitative gas chromatography/mass spectroscopy (GC/MS) analysis of the recovered liquid showed a substantial decrease of oxygen-containing species with a significant increase in carbon-rich (≥C6) aromatic hydrocarbons. The extent of deoxygenation was location-specific and dependent upon temperature and the relative concentrations of water, oxygenates, and residual solids in the approach vapor. The study provides the engineering practicality to catalytic vapor upgrading and offers the necessary data for the design and optimization of a full-stream upgrading of pyrolysis oils via in situ vapor cracking. [ABSTRACT FROM AUTHOR]

• For most scenarios, densifying biomass does not improve the economics. • Densification is economically advantageous when there is a high feedstock competition. • The plant size of a densification facility has a minimal impact on the overall economics. Biomass such as switchgrass can be converted to renewable gasoline and diesel (RGD) fuels via integrated fast pyrolysis and hydrodeoxygenation. However, the low bulk density of biomass feedstocks produces relatively high transportation costs, driven by the large volumes needed to supply biorefineries. Densification can reduce transportation volumes, and therefore transportation costs for bioenergy production. However, the additional costs of biomass densification, along with decreases in overall mass and energy yields, influence the overall economic performance of RGD production. This study investigated the techno-economic impacts of pelletizing, torrefying, or pyrolyzing the biomass at distributed facilities prior to upgrading the intermediates to RGD at a centralized facility. Eight scenarios were considered. When there is no feedstock competition, biomass densification at the distributed facility was shown to reduce the transportation cost by 20%–50%. However, the capital and operating costs required for densifying biomass increased the total cost of RGD production by 3%–35% compared to RGD made from non-densified biomass. The cost of making RGD from densified biomass was only reduced below the cost of making RGD from non-densified biomass for the case when the fraction of land surrounding the biorefinery facility allocated to the biomass cultivation is less than 0.25. This finding is attributed to the high cost of transporting non-densified biomass from a larger procurement radius. Sensitivity analysis indicated that RGD fuel yield, densification costs, project investment, and the rate of return all have significant impacts on the overall economics of RGD production. [ABSTRACT FROM AUTHOR]

Seamless co-processing of pyrolysis bio-oil within existing petroleum refineries is the most synergistic and economic way to improve biorefinery output. Coprocessing bio-oil with vacuum gas oil (VGO) is one logical pathway. Bio-oil has a viscosity and molecular weight range similar to that of VGO, and the hydrogen-rich nature of VGO can chemically complement the bio-oil hydrogen deficiency. Distillation of biomass pyrolysis oils produces solid residues with a significant fraction of fixed carbon and heavy volatiles. Maximization of yields of light compounds like olefins and gasoline-range aromatics are crucial for both attainment of desired product output levels as well as to follow methods that mimic petroleum-based methods and chemistries. Herein we discuss a systematic study on the additive coprocessing of specific bio-oil distillation bottoms with VGO. Tail-gas reactive pyrolysis (TGRP) bio-oils from spirulina, switchgrass, and guayule biomasses were distilled, and their bottoms were subject to analytical experiments in mixtures with VGO over different zeolite catalysts (no catalyst, HZSM-5, Y-zeolite). Switchgrass-based bottoms exhibit greater hydrogen deficiency and higher oxygen content compared with that of spirulina or guayule. Switchgrass-based bottoms, with or without VGO, produced more aromatics and less olefins and alkanes, compared with spirulina or guayule bottoms. When compared across different mixing ratios, thermal cracking of a 10:1 guayule/VGO mixture resulted in higher aromatics yields than even the VGO by itself. Addition of more VGO up to a 1:1 ratio of VGO/switchgrass bottoms nearly tripled the production of BTEX compounds. For hydrogen-rich bottoms spirulina and guayule, LPG-range olefins yields increased nearly 50% for 1:1 VGO/bottoms blends, compared with theoretical yields. [ABSTRACT FROM AUTHOR]

The tire industry is currently considering natural rubber from guayule ( Parthenium argentatum Gray ) as a viable alternative to imported Hevea natural rubber, or petroleum-based synthetics, to meet expanding materials needs of the industry. However, only 5–10% of the harvested guayule plant is converted into rubber latex. For economic sustainability, the industry must identify viable uses for the balance residual, termed bagasse. Bioenergy production has been considered, but conversion facilities must be co-located to avoid additional costs in transportation of the bagasse. This study investigated the economics of processing a minimum of 200 metric ton per day (MTPD) of guayule bagasse to produce biofuels in a biorefinery co-located with a guayule latex processing facility. A unique aspect of the simulated process was the use of the tail gas reactive pyrolysis (TGRP) technology that formulates an intermediate bio-oil with less oxygenates and therefore requires only mild upgrading to fuel products. This achieved a yield of 16.2%, distributed in the gasoline (9.7%), jet fuel (5.6%), and diesel (0.9%) carbon ranges. The capital cost was estimated at $58.74 million (MM), and the annual operating cost was estimated at $14.19 MM. A discounted cash flow rate of return (DCFROR) analysis was conducted to evaluate the economic feasibility based on a 30-year plant life and 10% internal rate of return. The minimum fuel selling price (MFSP) calculated was 1.88 $/L for gasoline, 1.84 $/L for jet fuel and 1.91 $/L for diesel fuel, clearly showing the limitations imposed by economies of scale of the current guayule bagasse availability. However, there is a potential to reduce the MFSP by increasing the facility capacity and utilizing the valuable co-products that accompany guayule pyrolysis biorefining. Sensitivity analysis indicates the MFSP of gasoline can be lowered to 0.96 $/L considering the most optimistic scenario, comprising an integrated large facility of 2000 MTPD, lower cost of hydrogen, and the sale of a premium-quality residual guayule biorefinery coke. [ABSTRACT FROM AUTHOR]

Hydrodeoxygenation (HDO) of pyrolysis oil is well understood as an upgrading method; however, the high processing pressures associated with it alone justify the exploration of alternative upgrading solutions, especially those that could adapt pyrolysis oils into the existing refinery infrastructure. Catalytic cracking is one such alternative industrial practice that can be carried out at near-atmospheric pressure using zeolite-based FCC catalysts. The present study focuses on the catalytic cracking of pyrolysis oil of different starting compositions over HZSM-5 to inform the extent of upgrading in the liquid phase. After establishing a catalyst bed temperature of 500 °C as the optimum operating condition with regard to deoxygenation and yield of mono-aromatics in the products obtained, the performances of conventional pyrolysis and tail gas reactive pyrolysis (TGRP) bio-oils as starting liquids for the cracking were compared. The results indicate that the formation of naphthalenes was favored, while the formation of benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds was slightly depressed in the case of the TGRP oil. We attribute this finding to the formation of naphthalenes from BTEX molecules already found in the TGRP oil. Subsequent reuse of the catalysts showed that the cracking of TGRP bio-oil exhibited slightly greater deactivation after a third cycle, likely due to the increased formation of naphthalenes and coke which can block HZSM-5 pores. The results obtained from this study will help determine the issues that need to be addressed when developing a catalytic cracker with HZSM-5 for regular pyrolysis oil and TGRP oil. [ABSTRACT FROM AUTHOR]

The techno-economics for producing liquid fuels from Maine forest residues were determined from a combination of: (1) laboratory experiments at USDA-ARS’s Eastern Regional Research Center using hog fuel (a secondary woody residue produced from mill byproducts such as sawdust, bark and shavings) as a feedstock for pyrolysis to establish product yields and composition, and (2) Aspen Plus® process simulation for a feed rate of 2000 dry metric tons per day to estimate energy requirements and equipment sizes. The simulated plant includes feedstock sizing and drying, pyrolysis, hydrogen production and hydrotreatment of pyrolysis oils. The biomass is converted into bio-oil (61% yield), char (24%) and gases (15%) in the pyrolysis reactor, with an energy demand of 17%. The bio-oil is then hydrotreated to remove oxygen, thereby producing hydrocarbon fuels. The final mass yield of gasoline/diesel hydrocarbons is 16% with a 40% energy yield based on the dry biomass fed, this yield represents a fuel production of 51.9 gallons per dry metric ton of feedstock. A unique aspect of the process simulated herein is that pyrolysis char and gases are used as sources for both thermal energy and hydrogen, greatly decreasing the need to input fossil energy. The total capital investment for a grass-roots plant was estimated to be US$427 million with an annual operational cost of US$154 million. With a 30 year project life, a minimum fuel selling price was determined to be US$6.25 per gallon. The economic concerns are related to high capital costs, high feedstock costs and short hydrotreating catalyst lifetimes. [ABSTRACT FROM AUTHOR]

The catalytic pyrolysis of Spirulina ( Arthrospira spp.) over several zeolite catalysts using pyrolysis/GC–MS was studied to explore the optimum and scalable conditions for the production of stable liquid intermediates via analysis of the condensable vapors. Nine catalysts of different pore sizes, shapes and SiO 2 /Al 2 O 3 ratios were tested in this study including H-ZSM5 (SiO 2 /Al 2 O 3 = 23), H-ZSM5 (50), H-ZSM5 (280), H-β (25), H-β (38), H-β (300), H-Y, mordenite and ferrierite at three catalyst/biomass ratios (1:1, 5:1 and 10:1). It was found that the high acidity HZSM-5 catalysts with low SiO 2 /Al 2 O 3 ratios (Si/Al = 23) could maximize the conversion of Spirulina to aromatic hydrocarbons, but lower acidity catalysts increased the production of aliphatic hydrocarbons, phenols and certain nitrogenates. The component analysis shows that it is possible to favor one set of chemical species over another for the conversion of Spirulina by varying the catalyst types and loadings allowing for the flexibility to engineer scaled systems for greater yields of particular chemical classes such as aromatic hydrocarbons, phenols, and aromatic nitrogenates via the manipulation of the catalyst properties or loadings. [ABSTRACT FROM AUTHOR]

The resource efficiency of biofuelproduction via biomass pyrolysisis evaluated using exergy as an assessment metric. Three feedstocks,important to various sectors of U.S. agriculture, switchgrass, forestresidue, and equine waste, are considered for conversion to bio-oil(pyrolysis oil) via fast pyrolysis, a process that has been identifiedas adaptable to on- or near-farm application. Biomass and biofuelproduction pathways are defined, material flows are determined, andexergy in- and outflows associated with biomass production and conversionare computed, including the depletion of exergy from its natural state(cumulative exergy demand, CExD). Sources of exergy depletion arequantified and categorized by energy carriers, e.g., electricity anddiesel fuel, and materials, e.g., fertilizer, as well as renewableand nonrenewable resources. Yields for biomass to bio-oil conversionby fast pyrolysis are determined experimentally. Breeding factors,a measure of exergy production (the ratio of the chemical exergy ofthe output product to process exergy inputs), are determined for theproduction of biomass and bio-oil. The quantification of exergy depletionfor process pathways enables the possible identification of more sustainable(resource efficient) pathways for biomass and bio-oil production.It is shown, for example, that feedstocks grown primarily for biomasssuch as switchgrass may be less sustainable using the exergy measurecompared to use of residue (e.g., forest thinnings) or waste biomass(e.g., equine waste). With regard to the pyrolysis process, thereis substantial reduction in exergy depletion when the coproducts noncondensablegases and biochar are recycled and utilized as a source of heat. Thesustainability of biomass production and conversion, as measured byexergy depletion, is strongly influenced by energy carriers. The studyreveals that the method of electricity production, i.e., on-site generationor grid electricity, as well as the choice of grid electricity canhave a significant impact on sustainability. The exergy content ofthe bio-oil produced varies from 24 to 27 MJ/kg bio-oil, which ismuch lower than traditional fuels. However, the cumulative exergydepletion for the production and conversion to bio-oil varies fromapproximately 4 to 11 MJ/kg bio-oil, which is also much lower thantraditional fuels. Breeding factors for biomass production and conversionto bio-oil based on cumulative exergy depletion vary from approximately2 to 5, demonstrating the potential exergy benefit of bio-oil productionusing fast pyrolysis. [ABSTRACT FROM AUTHOR]

A cellulose-derived fraction of biomass pyrolysis vaporwas simulated by evaporating acetol and acetic acid with heated nitrogen.After generating the vapor/nitrogen mixture, it was superheated ina tube oven and condensed by contact with an aqueous mist createdby an ultrasonic spray nozzle. The rates of condensation and fractionsof vapor condensed were determined for various fluid flow rates toestimate liquid flow rates necessary to obtain complete acetol vaporcondensation. The effect of noncondensible gas on the condensationwas determined by varying the ratio of nitrogen to acetol vapor. Forstandard conditions, no effect of nitrogen content on rate was seenfor vapor contents greater than 10 mol %, which would include anypractical fast pyrolysis vapor. Increasing the concentration of condensedvapor in the aqueous solution spray, up to 30 wt %, had little effecton the condensation rate. [ABSTRACT FROM AUTHOR]

Abstract: The pyrolytic conversion of oak sawdust at 500°C in flowing He over eight proprietary catalysts is described and compared to the control bed material, quartz sand. The reactions were conducted and compared in two reactors, an analytical, μg-scale pyroprobe reactor and a bench, g-scale packed bed reactor. The catalysts examined were modified acid catalysts, dealuminated-zeolite Y, β-zeolite, a naturally occurring metal hydroxide containing mineral, mordenite, and a mesoporous aluminosilicate molecular sieve. The packed bed reactor allowed the collection of three bulk product fractions, char, liquid, and gas, all of which could not be obtained from the μg-scale pyroprobe reactions. The catalysts effect on the mass balance of the bulk fractions tended toward more chars and less liquid compared to the sand control. The catalysts’ effects on the liquid products obtained in both reactors shifted away from acetic acid, furfural and higher molecular weight phenolics obtained with sand to lower molecular weight aromatics. This halved the total acid number of the liquid fraction and raised the pH by up to 1.4 units. The modified catalysts’ effects on the gas products from both reactors did not follow a specific trend. Instead, specific catalysts were able to enrich specific gas species up to a factor of 15 while suppressing the formation of others compared to the sand control. Two catalysts, β-zeolite and a naturally occurring metal hydroxide containing mineral, were regenerated and recycled up to five times with no loss of activity. [Copyright &y& Elsevier]