Co-pyrolysis of biomass and soapstock in a downdraft reactor using a novel ZSM-5/SiC composite catalyst

Catalytic pyrolysis of biomass over zeolites for bio-oil and chemical production: A review on their structure, porosity and acidity co-relation

The oxygenated compounds found in bio-oil limit their application as a transportation fuel. Several studies were reported on eliminating the oxygenated components from bio-oil so as to improve its fuel properties. This work is dedicated to studying the shape selectivity, porosity, structure, acidity of zeolites and their effect in bio-oil and chemicals production. The unified pore size, specific structure, controlled Si/Al ratio, unique channels and circular entrances, mesoporosity, and acidity are the utmost discerning parameters for aromatics production and deoxygenation reaction. The conversion of biomass-derived oxygenates to aromatics using zeolite is subjected to the reactants entering the pore, conversion inside the pore, and diffusing out of the products from the zeolite pores. These approaches were considered for an in-depth understanding of zeolite properties, which will enhance the fundamental understanding of pyrolysis.

Catalytic pyrolysis of lignocellulosic biomass for bio-oil production: A review

Catalytic pyrolysis has been widely explored for bio-oil production from lignocellulosic biomass owing to its high feasibility and large-scale production potential. The aim of this review was to summarize recent findings on bio-oil production through catalytic pyrolysis using lignocellulosic biomass as feedstock. Lignocellulosic biomass, structural components and fundamentals of biomass catalytic pyrolysis were explored and summarized. The current status of bio-oil yield and quality from catalytic fast pyrolysis was reviewed and presented in the current review. The potential effects of pyrolysis process parameters, including catalysts, pyrolysis conditions, reactor types and reaction modes on bio-oil production are also presented. Techno-economic analysis of full-scale commercialization of bio-oil production through the catalytic pyrolysis pathway was reviewed. Further, limitations associated with current practices and future prospects of catalytic pyrolysis for production of high-quality bio-oils were summarized. This review summarizes the process of bio-oil production from catalytic pyrolysis and provides a general scientific reference for further studies.

Porous Silicon Carbide (SiC): A Chance for Improving Catalysts or Just Another Active-Phase Carrier?

There is an obvious gap between efforts dedicated to the control of chemicophysical and morphological properties of catalyst active phases and the attention paid to the search of new materials to be employed as functional carriers in the upgrading of heterogeneous catalysts. Economic constraints and common habits in preparing heterogeneous catalysts have narrowed the selection of active-phase carriers to a handful of materials: oxide-based ceramics (e.g. Al₂O₃, SiO₂, TiO₂, and aluminosilicates-zeolites) and carbon. However, these carriers occasionally face chemicophysical constraints that limit their application in catalysis. For instance, oxides are easily corroded by acids or bases, and carbon is not resistant to oxidation. Therefore, these carriers cannot be recycled. Moreover, the poor thermal conductivity of metal oxide carriers often translates into permanent alterations of the catalyst active sites (i.e. metal active-phase sintering) that compromise the catalyst performance and its lifetime on run. Therefore, the development of new carriers for the design and synthesis of advanced functional catalytic materials and processes is an urgent priority for the heterogeneous catalysis of the future. Silicon carbide (SiC) is a non-oxide semiconductor with unique chemicophysical properties that make it highly attractive in several branches of catalysis. Accordingly, the past decade has witnessed a large increase of reports dedicated to the design of SiC-based catalysts, also in light of a steadily growing portfolio of porous SiC materials covering a wide range of well-controlled pore structure and surface properties. This review article provides a comprehensive overview on the synthesis and use of macro/mesoporous SiC materials in catalysis, stressing their unique features for the design of efficient, cost-effective, and easy to scale-up heterogeneous catalysts, outlining their success where other and more classical oxide-based supports failed. All applications of SiC in catalysis will be reviewed from the perspective of a given chemical reaction, highlighting all improvements rising from the use of SiC in terms of activity, selectivity, and process sustainability. We feel that the experienced viewpoint of SiC-based catalyst producers and end users (these authors) and their critical presentation of a comprehensive overview on the applications of SiC in catalysis will help the readership to create its own opinion on the central role of SiC for the future of heterogeneous catalysis.

Integrating pyrolysis and ex-situ catalytic reforming by microwave heating to produce hydrocarbon-rich bio-oil from soybean soapstock

The composite catalysts were synthesized with SiC powder and ZSM-5 and were characterized by Brunauer-Emmett-Teller, X-ray diffraction, thermogravimetric analysis, pyridine-infrared spectroscopy, and scanning electron microscopy. The catalysts showed a high heating rate and excellent catalytic performance for pyrolysis vapors, and the product fractional distribution and chemical compositions of bio-oil in a tandem system (microwave pyrolysis and microwave ex-situ catalytic reforming) was examined. Experimental results confirmed the quality of bio-oil produced by the microwave-induced catalytic reforming was better than that product through electric heating. Additionally, 36.94 wt% of bio-oil was obtained using the catalyst with 20%ZSM-5/SiC under the following conditions: feed-to-catalyst ratio, 2:1; pyrolysis temperature, 550 °C; and catalytic temperature, 350 °C. The selectivities of hydrocarbons reached up to 75.88%. After five cycles, the activity of the regenerated composite catalyst was retained at 95% of the original catalyst.

Synergistic effects on cellulose and lignite co-pyrolysis and co-liquefaction

The synergistic effects of lignite and cellulose co-pyrolysis and co-liquefaction were investigated. The optimal liquid fuel yield of co-pyrolysis was 34.72% at a reaction temperature of 550 °C, with a holding time of 30 min, whereas that of co-liquefaction was 39.26% at a reaction temperature of 340 °C, with a holding time of 30 min, an ethanol content of 60% in sub-/supercritical ethanol-water, and a liquid-material ratio of 10:1 (ml/g). Liquid fuel obtained under the best conditions was performed using Fourier transform infrared (FTIR) spectroscopy and gas chromatograph-mass spectrometer (GC-MS). The results of liquid fuel characterization showed that a synergy in co-pyrolysis and co-liquefaction, and the synergy of co-liquefaction was better than that of co-pyrolysis. The reaction mechanism revealed that the presence of the electron-supplying groups generated from cellulose cracking and ethanol reduced the bond energy in the macromolecular structure of lignite and promoted the thermal conversion of lignite.

Antifungal activity of water-soluble products obtained following the liquefaction of cornstalk with sub-critical water

Cornstalks are the leftover leaves and stems in a field after corn harvest. They are a potential biomass resource but are underutilized in agricultural production systems. To examine the chemical components in cornstalks and their corresponding functions, blocky cornstalks were treated in water at temperatures of 190, 210, 230, 250, and 270 °C in a high-pressure reactor. Water-soluble products (WSPs) were extracted from these treatments, and their chemical compositions were analyzed using gas chromatography-mass spectrometry (GC-MS), and their antifungal activities were determined using a bioassay. It was found that WSPs contained 28.7-40.1% phenols, 27.9-36.6% ketones, 0-2.6% alcohols, 4.9-10.1% esters, 5.4-7.8% organic acids, 1.3-12% aldehydes, and 5.5-18.4% of other organic compounds such as nitrogen- and sulfur-containing compounds, furan compounds, and benzene compounds. The inhibition the growth of the plant pathogen Fusarium oxysporum by WSPs was affected by temperature. WSP-270 (obtained at 270 °C) exhibited the best growth-inhibition efficacy. Under a biomicroscope, WSP-270-treated F. oxysporum showed a deformed and swollen hypha, and an increased number of bifurcations, as well as an expansion of growing apexes of new bifurcations. Therefore, the antifungal activity of WSPs could be used to manage soilborne plant pathogens.