Jungho Jae

Production of green aromatics and olefins by catalytic fast pyrolysis of wood sawdust

Catalytic fast pyrolysis of pine wood sawdust and furan (a model biomass compound) with ZSM-5 based catalysts was studied with three different reactors: a bench scale bubbling fluidized bed reactor, a fixed bed reactor and a semi-batch pyroprobe reactor. The highest aromatic yield from sawdust of 14% carbon in the fluidized bed reactor was obtained at low biomass weight hourly space velocities (less than 0.5 h−1) and high temperature (600 °C). Olefins (primarily ethylene and propylene) were also produced with a carbon yield of 5.4% carbon. The biomass weight hourly space velocity and the reactor temperature can be used to control both aromatic yield and selectivity. At low biomass WHSV the more valuable monocyclic aromatics are produced and the formation of less valuable polycyclic aromatics is inhibited. Lowering the reaction temperature also results in more valuable monocyclic aromatics. The olefins produced during the reaction can be recycled to the reactor to produce additional aromatics. Propylene is more reactive than ethylene. Co-feeding propylene to the reactor results in a higher aromatic yield in both continuous reactors and higher conversion of the intermediate furan in the fixed bed reactor. When olefins are recycled aromatic yields from wood of 20% carbon can be obtained. After ten reaction–regeneration cycles there were metal impurities deposited on the catalyst, however, the acid sites on the zeolite are not affected. Of the three reactors tested the batch pyroprobe reactor yielded the most aromatics, however, the aromatic product is largely naphthalene. The continuous reactors produce less naphthalene and the sum of aromatics plus olefin products is higher than the pyroprobe reactor.

Production of renewable jet fuel range alkanes and commodity chemicals from integrated catalytic processing of biomass

This article presents results from experimental studies and techno-economic analysis of a catalytic process for the conversion of whole biomass into drop-in aviation fuels with maximal carbon yields. The combined research areas highlighted include biomass pretreatment, carbohydrate hydrolysis and dehydration, and catalytic upgrading of platform chemicals. The technology centers on first producing furfural and levulinic acid from five- and six-carbon sugars present in hardwoods and subsequently upgrading these two platforms into a mixture of branched, linear, and cyclic alkanes of molecular weight ranges appropriate for use in the aviation sector. Maximum selectivities observed in laboratory studies suggest that, with efficient interstage separations and product recovery, hemicellulose sugars can be incorporated into aviation fuels at roughly 80% carbon yield, while carbon yields to aviation fuels from cellulose-based sugars are on the order of 50%. The use of lignocellulose-derived feedstocks rather than commercially sourced model compounds in process integration provided important insights into the effects of impurity carryover and additionally highlights the need for stable catalytic materials for aqueous phase processing, efficient interstage separations, and intensified processing strategies. In its current state, the proposed technology is expected to deliver jet fuel-range liquid hydrocarbons for a minimum selling price of

Depolymerization of lignocellulosic biomass to fuel precursors: maximizing carbon efficiency by combining hydrolysis with pyrolysis

4.75 per gallon assuming nth commercial plant that produces 38 million gallons liquid fuels per year with a net present value of the 20 year biorefinery set to zero. Future improvements in this technology, including replacing precious metal catalysts by base metal catalysts and improving the recyclability of water streams, can reduce this cost to

The Role of Ru and RuO2 in the Catalytic Transfer Hydrogenation of 5-Hydroxymethylfurfural for the Production of 2,5-Dimethylfuran

2.88 per gallon.

Mechanistic Insights from Isotopic Studies of Glucose Conversion to Aromatics Over ZSM‐5

In this paper we study the carbon efficiency of combining hydrolysis and pyrolysis processes using maple wood as a feedstock. A two-step hydrolysis of maple wood in batch reactors, that consisted of a thermochemical pretreatment in water followed by enzymatic hydrolysis, achieved an 88.7 wt% yield of glucose and an 85 wt% yield of xylose as liquid streams. The residue obtained was 80 wt% lignin. A combination of TGA and pyroprobe studies was used for the pyrolysis of pure maple wood, hemicellulose-extracted maple wood, and the lignin residue from the hydrolysis of maple wood. Pyrolysis of raw maple wood produced 67 wt% of condensable liquid products (or bio-oils) that were a mixture of compounds including sugars, water, phenolics, aldehydes, and acids. Pyrolysis of hemicellulose-extracted maple wood (the solid product after pretreatment of maple wood) showed similar bio-oil yields and compositions to raw maple wood while pyrolysis of the lignin residue (the final solid product of enzymatic hydrolysis) produced only 44.8 wt% of bio-oil. The bio-oil from the lignin residue is mostly composed of phenolics such as guaiacol and syringol compounds. Catalytic fast pyrolysis (CFP) of maple wood, hemicellulose-extracted maple wood, and lignin residue produced 18.8, 16.6 and 10.1 wt% aromatic products, respectively. Three possible options for the integration of hydrolysis with pyrolysis processes were evaluated based on their material and carbon balances: Option 1 was the pyrolysis/CFP of raw maple wood, option 2 combined hemicellulose extraction by hydrolysis with pyrolysis/CFP of hemicellulose-extracted maple wood, and option 3 combined the two-step hydrolysis of hemicellulose and cellulose sugar extraction with pyrolysis/CFP of the lignin residue. It was found that options 1, 2, and 3 all have similar overall carbon yields for sugars and bio-oils of between 66 and 67%.

Identification and thermochemical analysis of high-lignin feedstocks for biofuel and biochemical production

We have previously shown that 2,5‐dimethylfuran (DMF) can be produced selectively from 5‐hydroxymethylfurfural in up to 80 % yield via catalytic transfer hydrogenation with 2‐propanol as a hydrogen donor and Ru/C as a catalyst. Herein, we investigate the active phase of the Ru/C catalyst by using extended X‐ray absorption fine structure, X‐ray photoelectron spectroscopy, and high‐resolution TEM analyses. The results reveal that RuO2 is the dominant phase in the fresh (active) catalyst and is reduced to metallic Ru during the reaction with the hydrogen produced in situ from 2‐propanol. The deactivation of the catalyst is correlated with the reduction of the surface of RuO2. Reactivity studies of individual phases (bulk RuO2 and reduced Ru/C catalysts) indicate that RuO2 mainly catalyzes the Meerwein–Ponndorf–Verley reaction of 5‐hydroxymethylfurfural that produces 2,5‐bis(hydroxymethyl)furan and the etherification of 2,5‐bis(hydroxymethyl)furan or other intermediates with 2‐propanol and that the reduced Ru/C catalyst has moderate hydrogenolysis activity for the production of DMF (30 % selectivity) and other intermediates (20 %). In contrast, a physical mixture of the two phases increases the DMF selectivity up to 70 %, which suggests that both metallic Ru and RuO2 are active phases for the selective production of DMF. The oxidation of the reduced Ru/C catalyst at different temperatures and the in situ hydrogen titration of the oxidized Ru/C catalysts were performed to quantify the bifunctional role of Ru and RuO2 phases. The mild oxidation treatment of the Ru/C catalyst at 403 K could activate the catalyst for the selective production of DMF in up to 72 % yield by generating a partially oxidized Ru catalyst.

Global bioenergy potential from high-lignin agricultural residue

Due to its low cost and large availability, lignocellulosic biomass is being studied worldwide as a feedstock for renewable liquid biofuels. There are currently several routes being studied to convert solid biomass to a liquid fuel, which involve multiple steps, thus greatly increasing the cost of biomass conversion. We have recently shown that aromatics can be directly produced from solid biomass in a single step by catalytic fast pyrolysis (CFP) with ZSM-5 catalysts. The advantages of this approach are that aromatics can be directly produced from biomass in a single low-cost step with inexpensive zeolite-based catalysts. The desired reactions all occur inside the zeolite catalyst. Other researchers have used zeolite catalysts for conversion of biomass-derived feedstocks into aromatics, including the early work in the 1980 s by Chen et al. and Dao et al. on the conversion of aqueous sugar solutions and more recently pyrolysis oils and lignocellulosic feedstocks. The main challenge when using zeolite catalysts is controlling the complicated chemistry that occurs inside the catalyst pores. The objective of this study is to elucidate the reaction mechanism for conversion of biomass-derived oxygenates inside zeolite catalysts by performing isotopic studies. These findings give us insight into how we might control zeolite chemistry for the conversion of biomass into aromatics. Glucose is used as a model compound for cellulosic biomass in this study. We have previously shown that both glucose and cellulose yield similar product distributions when pyrolized in the presence of ZSM-5 catalyst. These previous findings suggest that both cellulose and glucose decompose to common intermediates. Therefore the mechanistic conclusions from this paper can be extended to more complicated cellulosic-type feedstocks. Catalytic pyrolysis of C and C glucose in the presence of ZSM-5 catalyst was conducted using a pyroprobe model 2000 analytical pyrolyzer. Products from the pyroprobe were sent directly to a GC/MS system via a helium carrier gas stream. In the first set of experiments, a 1:1 w/w mixture of pure C and C glucose was pyrolyzed at two different catalyst/feed ratios (2.3:1 and 19:1). In a second set of experiments a 1:1 w/w mixture of C benzene and C glucose was pyrolyzed to determine the role of single-ring aromatics in the formation of polycyclic aromatics. In the last set of experiments, a 1:1 w/w mixture of C naphthalene and C glucose was pyrolyzed to determine whether naphthalene is susceptible to alkylation reactions. Our experimental results indicate that three main reaction pathways dominate the formation of aromatics during the catalytic pyrolysis of glucose. The first step in catalytic pyrolysis is the homogenous thermal decomposition of glucose into volatile compounds like anhydrosugars (Scheme 1 a). These anhydrosugars then undergo dehydration, bond cleavage, and rear-

Cascade of Liquid‐Phase Catalytic Transfer Hydrogenation and Etherification of 5‐Hydroxymethylfurfural to Potential Biodiesel Components over Lewis Acid Zeolites

BackgroundLignin is a highly abundant biopolymer synthesized by plants as a complex component of plant secondary cell walls. Efforts to utilize lignin-based bioproducts are needed.ResultsHerein we identify and characterize the composition and pyrolytic deconstruction characteristics of high-lignin feedstocks. Feedstocks displaying the highest levels of lignin were identified as drupe endocarp biomass arising as agricultural waste from horticultural crops. By performing pyrolysis coupled to gas chromatography-mass spectrometry, we characterized lignin-derived deconstruction products from endocarp biomass and compared these with switchgrass. By comparing individual pyrolytic products, we document higher amounts of acetic acid, 1-hydroxy-2-propanone, acetone and furfural in switchgrass compared to endocarp tissue, which is consistent with high holocellulose relative to lignin. By contrast, greater yields of lignin-based pyrolytic products such as phenol, 2-methoxyphenol, 2-methylphenol, 2-methoxy-4-methylphenol and 4-ethyl-2-methoxyphenol arising from drupe endocarp tissue are documented.ConclusionsDifferences in product yield, thermal decomposition rates and molecular species distribution among the feedstocks illustrate the potential of high-lignin endocarp feedstocks to generate valuable chemicals by thermochemical deconstruction.

Catalytic Hydrodeoxygenation of Bio-oil Model Compounds over Pt/HY Catalyst

Almost one-quarter of the worlds population has basic energy needs that are not being met. Efforts to increase renewable energy resources in developing countries where per capita energy availability is low are needed. Herein, we examine integrated dual use farming for sustained food security and agro-bioenergy development. Many nonedible crop residues are used for animal feed or reincorporated into the soil to maintain fertility. By contrast, drupe endocarp biomass represents a high-lignin feedstock that is a waste stream from food crops, such as coconut (Cocos nucifera) shell, which is nonedible, not of use for livestock feed, and not reintegrated into soil in an agricultural setting. Because of high-lignin content, endocarp biomass has optimal energy-to-weight returns, applicable to small-scale gasification for bioelectricity. Using spatial datasets for 12 principal drupe commodity groups that have notable endocarp byproduct, we examine both their potential energy contribution by decentralized gasification and relationship to regions of energy poverty. Globally, between 24 million and 31 million tons of drupe endocarp biomass is available per year, primarily driven by coconut production. Endocarp biomass used in small-scale decentralized gasification systems (15–40% efficiency) could contribute to the total energy requirement of several countries, the highest being Sri Lanka (8–30%) followed by Philippines (7–25%), Indonesia (4–13%), and India (1–3%). While representing a modest gain in global energy resources, mitigating energy poverty via decentralized renewable energy sources is proposed for rural communities in developing countries, where the greatest disparity between societal allowances exist.

Pyrolysis and catalytic upgrading of Citrus unshiu peel

We report a one‐step process for the production of diesel fuel from biomass‐derived 5‐hydroxymethylfurfural (HMF). The reaction proceeds through the sequential transfer hydrogenation and etherification of HMF to 2,5‐bis(alkoxymethyl)furan, a potential biodiesel additive, catalyzed by a Lewis acid zeolite, such as Sn‐Beta or Zr‐Beta. An alcohol is used as a hydrogen donor and as a reactant in etherification. This cascade reaction can selectively produce high yields of the biodiesel additive (>80 % yield) from HMF with the Sn‐Beta catalyst and secondary alcohols, such as 2‐propanol and 2‐butanol.