Bryan D. Morreale

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Increased demand for liquid transportation fuels coupled with gradual depletion of oil reserves and volatile petroleum prices have recently renewed interest in coal-to-liquids (CTL) technologies. Large recoverable global coal reserves can provide liquid fuels and significantly reduce dependence on oil imports. Direct coal liquefaction (DCL) converts solid coal (H/C ratio ≈ 0.8) to liquid fuels (H/C ratio ≈ 2) by adding hydrogen at high temperature and pressures in the presence or absence of catalyst. This review provides a comprehensive literature survey of the coal structure, chemistry and catalysis involved in direct liquefaction of coal. This report also touches briefly on the historical development and current status of DCL technologies. Key issues, challenges involved in DCL process and directions for the future research are also addressed.

Development of membranes for hydrogen separation: Pd coated V–10Pd

Abstract Numerous group IVB and VB alloys were prepared and tested as potential membrane materials, but most of these materials were brittle or exhibited cracking during hydrogen exposure. One of the more ductile alloys, V–10Pd (at.-%), was fabricated into a thin foil (107 μm thick) composite membrane coated with 100 nm of Pd on each side. The material was tested for hydrogen permeability, resistance to hydrogen embrittlement, and long term hydrogen flux stability. The hydrogen permeability ϕ of the V–10Pd membrane was 3·86×10–8 mol m–1 s–1 Pa–0·5 (average of three different samples) at 400°C, which is slightly higher than the permeability of Pd–23Ag at that temperature. A 1400 h hydrogen flux test at 400°C demonstrated that the rate of metallic interdiffusion was slow between the V–10Pd foil and the 100 nm thick Pd coating on the surface. However, at the end of testing, the membrane cracked at 118°C because of hydrogen embrittlement.

Recent developments in the production of liquid fuels via catalytic conversion of microalgae: experiments and simulations

Due to continuing high demand, depletion of non-renewable resources and increasing concerns about climate change, the use of fossil fuel-derived transportation fuels faces relentless challenges both from a world markets and an environmental perspective. The production of renewable transportation fuel from microalgae continues to attract much attention because of its potential for fast growth rates, high oil content, ability to grow in unconventional scenarios, and inherent carbon neutrality. Moreover, the use of microalgae would minimize “food versus fuel” concerns associated with several biomass strategies, as microalgae do not compete with food crops in the food chain. This paper reviews the progress of recent research on the production of transportation fuels via homogeneous and heterogeneous catalytic conversions of microalgae. This review also describes the development of tools that may allow for a more fundamental understanding of catalyst selection and conversion processes using computational modelling. The catalytic conversion reaction pathways that have been investigated are fully discussed based on both experimental and theoretical approaches. Finally, this work makes several projections for the potential of various thermocatalytic pathways to produce alternative transportation fuels from algae, and identifies key areas where the authors feel that computational modelling should be directed to elucidate key information to optimize the process.

Determination of Free Fatty Acids and Triglycerides by Gas Chromatography Using Selective Esterification Reactions

A method for selectively determining both free fatty acids (FFA) and triacylglycerides (TAGs) in biological oils was investigated and optimized using gas chromatography after esterification of the target species to their corresponding fatty acid methyl esters (FAMEs). The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs. Complete conversion of both free acids and glycerides to corresponding FAMEs was found to require more rigorous reaction conditions involving heating to 120°C for up to 2 h. Method validation was provided using gas chromatography-flame ionization detection, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry. The method improves on existing methods because it allows the total esterified lipid to be broken down by FAMEs contributed by FFA compared to FAMEs from both FFA and TAGs. Single and mixed-component solutions of pure fatty acids and triglycerides, as well as a sesame oil sample to simulate a complex biological oil, were used to optimize the methodologies. Key parameters that were investigated included: HCl-to-oil ratio, temperature and reaction time. Pure free fatty acids were found to esterify under reasonably mild conditions (10 min at 50°C with a 2.1:1 HCl to fatty acid ratio) with 97.6 ± 2.3% recovery as FAMEs, while triglycerides were largely unaffected under these reaction conditions. The optimized protocol demonstrated that it is possible to use esterification reactions to selectively determine the free acid content, total lipid content, and hence, glyceride content in biological oils. This protocol also allows gas chromatography analysis of FAMEs as a more ideal analyte than glyceride species in their native state.

Gasification and Associated Degradation Mechanisms Applicable to Dense Metal Hydrogen Membranes

Dense metal membranes have been identified as a promising technology for post-gasifier forward water-gas shift (WGS) membrane reactors or post-shift membrane separation processes. It is known that both major and minor gasification effluent constituents can have adverse effects on the mechanical and chemical stability of potential metal membranes. With this in mind, the scope of this chapter is to provide introductions to the gasification process and dense metal membranes, and the possible degradation mechanisms that dense metal hydrogen membranes may encounter in gasification environments. Degradation mechanisms of interest include catalytic poisoning, oxidation, sulfidation and hydrogen embrittlement. Additionally, the influence of in-situ and post-WGS gas compositions and CO conversions on the aforementioned degradation mechanisms will be addressed.