A. V. Chistyakov

Conversion of biomass products to energy sources in the presence of nanocatalysts and membrane-catalyst systems

A particular role in the harmonious exploitation of raw materials is assigned to organic sources of fuels based on renewable biomass. The most promising feedstocks of major energy sources, such as hydrogen and organic components of motor fuels, include ethanol and other bioalcohols, i.e., the primary products of its conversion. In this work, we describe the results for new reactions of conversion of ethanol and a mixture of ethanol and glycerol, which are the major products of biomass, to the C3–C10 alkane-olefin fraction in the presence of nanoscale mono- and bimetal-containing active components supported on γ-Al2O3 (〈d〉 = 5–8 nm) and on the inner surface of microchannels of ceramic membranes (〈d〉 = 15–20 nm). Mono- and bimetallic alkoxide and acetate complexes are used as precursors. It is found that the selectivity for the ethanol conversion to aliphatic hydrocarbons, as well as the content of branched structures, heavily depends on the nuclearity and composition of metal-complex precursors supported on γ-Al2O3. It is found for the first time that glycerol exhibits high reactionary ability in the reaction of cross-condensation of the carbon skeleton of alcohols of different nature. In the presence of a Ta-Re-containing system, a mixture of ethanol and glycerol is converted to 60% of C4–C10+ olefins, which contain up to 50% of branched structures. It is shown that by varying the composition of Pd-Zn-containing active components, it is possible to targetedly convert ethanol to the olefin, alkane, or alkane-olefin fraction. Porous membrane-catalyst systems are designed to produce hydrogen and syngas from biomass products; the systems exhibit high activity in the carbon dioxide and steam reforming of ethanol, a mixture of ethanol and glycerol, and acetic acid. A scheme for the production of a wide range of valuable organic products based on bioalcohols containing no toxic impurities and independent of crude oil is described. According to this scheme, alkanes derived from ethanol and other bioalcohols are the major components of motor fuels; a large number of organic synthesis products can be derived from olefins, hydrogen, and carbon monoxide in the carbonylation/hydrocarbonylation processes.

Aromatization of propane: Techno-economic analysis by multiscale "kinetics-to-process" simulation

Abstract This paper addresses the techno-economic analysis of the propane aromatization process, by adopting a novel kinetics-to-process approach. The recent interest in this technological route derives from the development of new third generation biorefinery concepts, in which, algal oil is subjected to catalytic hydrodeoxygenation processes for the production of (Hydrotreated Renewable Jet) HRJ fuels. Beside biofuels, co-production of large amounts of propane is observed, which can be upgraded by a catalytic conversion to aromatics on zeolites. Kinetic studies of propane aromatization over H-ZSM-5 zeolite in a wide range of conversions are reported in the literature. Based on these results, a general kinetic model of propane aromatization has been developed. The revised kinetic scheme is then embedded in a process simulation, performed with the commercial code SimSci PRO/II by Schneider Electric. Basing on the process simulation and on available price assessments, a techno-economic analysis has been performed to show limits as well as potentialities of the proposed layout.

Selective deoxygenation of vegetable oils in the presence of Pt–Sn/Al2O3 catalyst

We studied deoxygenation of individual fatty esters and fatty acid triglycerides from vegetable oils and lipid extracts from microalgae in the presence of catalysts prepared by deposition of Pt–Sn-containing compounds onto the γ-aluminum oxide surface. Using individual esters as an example, selective reduction of oxygen into water was demonstrated for the first time to proceed on a catalytic system at the 5 : 1 molar ratio of Sn and Pt active components to afford hydrocarbon components of substrates in virtually quantitative yield. Transformation of vegetable oil in the presence of this catalyst affords the C3–C18 hydrocarbon fraction in yield up to 99% at the content of C3 and C18 hydrocarbons up to 90%. The fraction of C1 and C2 hydrocarbons and carbon oxides is not higher than 0.5%. The possibility of carbon weight loss minimization during transformation of lipids was shown for the first time.

Reductive dehydration of ethanol to hydrocarbons on Ni- and Au-containing nanocomposites

Monometallic and bimetallic nanocomposites M/Al2O3 (M = NiO, Au, NiO + Au) with metal contents of 0.1–0.65 wt % were prepared by the deposition-precipitation and/or impregnation technique. The surface of the composites was investigated by transmission electron microscopy (TEM), EDX, adsorption spectroscopy (AAS), and XAFS. The features of the M/Al2O3 catalysis of the reductive dehydration of ethanol at 350°C were investigated. The activity of NiO/Al2O3 containing 3.5 nm particles of NiO was 130 h−1. A strong size effect in activity was revealed for Au/Al2O3 nanocomposites with activity increasing from 341 to 1384 h−1 as the size of gold particles decreased from 13–20 to 5 nm. The selectivity of 5-nm particles of Au/Al2O3 to the fraction of C3-C8 hydrocarbons was 11.69 mass %. The growth of M particles due to the segregation of individual metals and/or the formation of mixed (Au + NiO) particles resulted in an increase in the selectivity of C3-C8 up to 34.19 mass %. The causes of the observed catalytic phenomena are discussed considering the reaction mechanisms and the specific structure features of the obtained catalysts.

Mechanism of the reductive dehydration of ethanol into C3+ alkanes over the commercial alumina—platinum catalyst AP-64

The mechanism of the reductive dehydration of ethanol (RDE) into C3+ alkanes over the commercial alumina—platinum catalyst AP-64 has been investigated. The catalyst pre-reduction time has an effect on the conversion of ethanol and on that of ethylene, a possible intermediate compound in the RDE reaction. Over the catalyst reduced for 12 h, ethanol turns into a C3-C12 alkane fraction and ethylene turns into a C3-C12 olefin fraction, whose yields are 39.0 and 31.4%, respectively. Energetic parameters of ethanol chemisorption and conversion on a Pt6Al4 cluster have been determined by the density functional theory method using the PRIRODA 13 program. Ethanol dehydration into ethylene proceeds via the successive breaking of C-H and C-O bonds, and the rate-determining step of the process depends on the atom (Pt or Al) to which the OH group of the alcohol is coordinated. Hydroxyl group transfer from the Pt atom to the nearest Al atom is energetically favorable here. It is hypothesized that the main role of the metal-containing cluster is donation of chemisorbed ethylene to the nearest acid sites, on which the ethylene oligomerizes into a C3-C10 hydrocarbon fraction.

Conversion of ethanol and glycerol to olefins over the Re- and W-containing catalysts

The catalytic conversion of a mixture of ethanol and glycerol over the Re—W/Al2O3 catalysts was studied. The Re—W binary system exhibits a non-additive cocatalytic effect in the conversion of ethanol and its mixture with glycerol into the fraction of olefins С4—С9. The non-additive increase in the catalytic activity is associated with the specific structure of the binuclear metallocomplex precursors, due to which the supported metals are arranged in the immediate vicinity from each other on the support surface and intensively interact to form Re7+. The study of the combined conversion of ethanol and glycerol made it possible to find an optimum ratio of the reactants in the initial mixture. The yield of target hydrocarbons attains 50 wt.% based on the amount of carbon passed through the reactor.

Conversion of biological substrates to fuel components in the presence of industrial catalysts

Conditions were found under which the industrial aluminum-platinum catalyst AP-64 and the pilot zeolite system Pd-Zn/Al2O3/MFI (MFI is a high-silica ZSM-5 type zeolite) catalyze single-stage highly selective conversion of rapeseed oil and ethanol to either alkane or alkanearomatic fraction of hydrocarbons suitable as engine fuel components. The hydrocarbon chain grows with participation of ethylene, which is formed in the argon medium directly from the ethanol molecule. Under these conditions, hydrogenation of this alkene on intermetallic clusters arising during the long-term reductive preactivation is suppressed. The alcohol supplies not only ethylene but also hydrogen. In the presence of Pd-Zn/Al2O3/MFI, ethanol is converted to alkanes and aromatic hydrocarbons according to independent pathways. Joint processing of alcohols and rapeseed oil in the presence of the Pd-Zn/Al2O3/MFI catalyst system is an efficient and promising route to C3-C11 hydrocarbons in the absence of an external source of hydrogen.

Self-sustainable Bio-methanol & Bio-char Coproduction from 2nd Generation Biomass Gasification

Self-Sustainable Bio-methanol & Bio-char Coproduction from 2 Generation Biomass Gasification Andre F. Amaral*, Giulia Bozzano, Carlo Pirola, Aleksey G. Goryunov, Andrey V. Chistyakov, Flavio Manenti a Polytechnic University of Milan, CMIC Dept. “Giulio Natta”, 32 Piazza Leonardo da Vinci, 20133 Milan, Italy b University of Milan, Chemistry Department, 19 Via Golgi, 20133 Milan, Italy c Tomsk Polytechnic University, Dept. of Electronics and Automation of Nuclear Plants, Tomsk, Russian Federation d A.V. Topchiev Institute of Petrochemical Synthesis, Leninsky prospect 29, Moscow, Russian Federation andre.furtado@polimi.it

Direct conversion of ethanol and fusel oils to alkane–aromatic hydrocarbons in the presence of a pilot Pd–Zn/TsVM catalyst

The conversion of ethanol and fusel oils to a С3–С12 alkane–aromatic fraction with high activity and selectivity in the presence of the Pd–Zn/TsVM pilot catalyst has been demonstrated. It has been shown that the ethanol conversion to alkanes and aromatic hydrocarbons in the presence of this catalyst proceeds by various routes to give ethylene and diethyl ether as intermediate products providing a 90–95% yield on the converted ethanol carbon basis for the target С3–С12 fraction containing up to 40% of branched alkanes.

Single-Stage Catalytic Coconversion of Vegetable Oils and Alcohols to the Alkane–Aromatic Hydrocarbon Fraction without Using Molecular Hydrogen

A method for the production of a С3–С11 alkane–aromatic hydrocarbon (HC) fraction by the coconversion of a mixture of alcohols simulating biomass fermentation products and vegetable oil without using molecular hydrogen has been developed. A characteristic feature of this method is the occurrence of coupled alcohol aromatization reactions evolving hydrogen consumed for the hydrogenation of unsaturated HC moieties formed from fatty acid triglycerides in the presence of a pilot sample of the Pd–Zn/TsVM/Al2O3 catalyst. It has been found that the optimum amount of vegetable oil in the feed mixture is 25–50 vol %; this amount provides the target fraction yield of up to 95% on a fed carbon basis.