Jean-Paul Lange

Furfural—A Promising Platform for Lignocellulosic Biofuels

Furfural offers a promising, rich platform for lignocellulosic biofuels. These include methylfuran and methyltetrahydrofuran, valerate esters, ethylfurfuryl and ethyltetrahydrofurfuryl ethers as well as various C(10)-C(15) coupling products. The various production routes are critically reviewed, and the needs for improvements are identified. Their relative industrial potential is analysed by defining an investment index and CO(2) emissions as well as determining the fuel properties for the resulting products. Finally, the most promising candidate, 2-methylfuran, was subjected to a road trial of 90,000 km in a gasoline blend. Importantly, the potential of the furfural platform relies heavily on the cost-competitive production of furfural from lignocellulosic feedstock. Conventional standalone and emerging coproduct processes-for example, as a coproduct of cellulosic ethanol, levulinic acid or hydroxymethyl furfural-are expensive and energetically demanding. Challenges and areas that need improvement are highlighted. In addition to providing a critical review of the literature, this paper also presents new results and analysis in this area.

Valeric biofuels: a platform of cellulosic transportation fuels.

The first generation of biofuels is presently produced fromsugars, starches, and vegetable oil. Although instrumental indeveloping the market, these biofuels are not likely to deliverthe large volumes needed for the transport sector becausethey directly compete with food for their feedstock. A morepromising feedstock is lignocellulosic material, which is moreabundant, has a lower cost, and is potentially more sustain-able.

Conversion of Furfuryl Alcohol into Ethyl Levulinate using Solid Acid Catalysts

Furfural, a potential coproduct of levulinic acid, can be converted into levulinic acid via hydrogenation to furfuryl alcohol and subsequent ethanolysis to ethyl levulinate. The ethanolysis reaction is known to proceed in the presence of H(2)SO(4). We show here that several strongly acidic resins are comparably effective catalysts for this reaction. Optimal performance is achieved by balancing the number of acid sites with their accessibility in the resin. Acidic zeolites such as H-ZSM-5 also catalyze this reaction, although with a lower activity and a higher co-production of diethyl ether.

Methanol synthesis: a short review of technology improvements

Abstract Methanol synthesis has undergone continuous improvements for over nearly a century. Among others are the advent of low-pressure synthesis, once-through designs, and advanced reforming technologies. In reviewing some 25 technologies, we will not dwell in technical details but focus on one major goal, i.e. minimising the investment costs. Our pragmatic indicator for investment savings will be the minimisation of energy transfer duty and, particularly, the minimisation of gas recycle and fuel firing.

Coke formation through the reaction of ethene over hydrogen mordenite. III: IR and 13C-NMR studies

IR and high-resolution solid-statel3C-NMR studies provided evidence for successive steps in coke formation upon reaction of ethene over the zeolite hydrogen mordenite. Adsorbed at room temperature, ethene polymerizes to branched and possibly also linear alkanes. Upon heating up to 500 K, the alkanes isomerize and crack. Meanwhile, the13C-NMR spectra show the formation of carbocations of alkylic, allylic and aromatic nature. Above 500 K, high-temperature coke develops under formation of alkylaromatics and subsequently small polyaromatic and/or polyphenylene molecules. Over dealuminated hydrogen mordenites, ethene also forms paraffinic deposits at low temperatures. Above 500 K, however, a substantial amount of C1C4 alkanes are formed together with unsaturated species.

Coke formation through the reaction of olefins over hydrogen mordenite: II. In situ EPR measurements under on-stream conditions

Depending on the reaction temperature, the carbonization of ethylene over hydrogen mordenite led to low-temperature coke radicals (below about 500 K) or high-temperature coke radicals (above about 500 K). The formation of low-temperature coke radicals, which are olefinic or allylic oligomeric species, is favored by an increase in the acidity of the zeolite catalyst. In the formation of high-temperature coke radicals, which are highly unsaturated species, homolytic bond splitting of carbonaceous deposits may be involved. The acidity of the zeolite affected the formation of the high-temperature coke radicals in a complex way. A comparison between EPR and thermogravimetric measurements showed a good linear correlation between the number of radicals and the amount of coke formed at high temperature.

Coke formation through the reaction of olefins over hydrogen mordenite. I. EPR measurements under static conditions

Depending on the reaction temperature, the carbonization of ethylene and propylene over hydrogen mordenite can be separated into two processes. Below 500 K, radicals of a low-temperature coke develop and are subsequently annihilated. Above 500 K, highly unsaturated radicals of high-temperature coke form. The presence of reactive species in the gas phase, which approximates the on-stream situation, may affect the carbonization of the low-temperature coke. However, radicals of the low-temperature coke do not appear to be necessary precursors of the high-temperature coke. Paramagnetic centers which are detectable after dehydration of the zeolite do not interact with the adsorbed olefins to form radicals.

Renewable feedstocks: the problem of catalyst deactivation and its mitigation

Much research has been carried out in the last decade to convert bio-based feedstock into fuels and chemicals. Most of the research focuses on developing active and selective catalysts, with much less attention devoted to their long-term stability. This Review considers the main challenges in long-term catalyst stability, discusses some fundamentals, and presents options for their mitigation. Three main challenges are discussed: catalyst fouling, catalyst poisoning, and catalyst destruction. Fouling is generally related to the deposition of insoluble components present in the feed or formed by degradation of the feed or intermediates. Poisoning is related to the deposition of electropositive contaminants (e.g. alkali and alkaline earth metals) on acid sites or of electronegative contaminants (e.g. N and S) at hydrogenation sites. Catalyst destruction results from the thermodynamic instability of most oxidic supports, solid acids/bases, and hydrogenation functions under hydrothermal conditions.

Fuels and Chemicals Manufacturing; Guidelines for Understanding and Minimizing the Production Costs

With increasing frequency,scientists and engineers are expected to understand and estimate the economic impact of their research and development efforts.Here,we provide simple concepts and tools used to understand the major cost contributions (e.g.,feed,investment or catalyst,and chemicals) for existing and emerging manufacturing technologies of chemicals and fuels.Particular attention will be paid to (i)selectivity and productivity for existing plants,(ii)energy management and its impact on investment costs,and (iii)cheaper feedstocks and their potential impact on investment costs.

PROCESSES FOR CONVERTING METHANE TO LIQUID FUELS: ECONOMIC SCREENING THROUGH ENERGY MANAGEMENT

Numerous process schemes have been proposed for converting methane to liquid hydrocarbon fuels. Economic evaluation studies generally conclude that none except the best of these schemes are attractive at present oil prices of <20