Gary J. Stiegel

Gasification technologies: the path to clean, affordable energy in the 21st century

The gasification of carbon-based solid and liquid materials has been around for nearly two hundred years and was used extensively for the production of town gas in the latter part of the nineteenth and twentieth centuries. Although this application has all but vanished, other applications have evolved, thus continuing gasifications important role as a commercial technology. Numerous advancements have been made since its introduction, leading to a more cost-competitive, thermally efficient, and environmentally friendly technology. However, as deregulation of the power industry continues and as increased environmental pressures are placed on industry, opportunities for further technological advances and expanded applications to meet these challenges will be created. In addition, these changes will likely restructure the technology and ownership objectives, placing premiums on efficiency, environmental acceptability, and the ability to utilize multiple feedstocks and produce multiple products. In the twentieth century, gasification will be the heart of a new generation of energy plants, possessing both feedstock and product flexibility, near-zero emission of pollutants, high thermal efficiency and capture of carbon dioxide, and low feedstock and operating and maintenance (O&M) costs.

Iron-based catalysts for slurry-phase Fischer-Tropsch process: Technology review

Abstract The slurry-phase reactor system is of interest in Fischer-Tropsch synthesis owing to the ability of the reactor system to efficiently remove the heat produced by the exothermic reaction. Iron-based catalysts are active for Fischer-Tropsch synthesis and for the water-gas shift reaction, and, in addition, are inexpensive. Hence, they have been examined in slurry-phase Fischer-Tropsch synthesis with CO-rich synthesis gas. The role of promoters, carbide phases, and oxide phases in iron-based catalysts is not well understood. The article reviews current knowledge of iron-based catalysts with reference to their application in slurry-phase Fischer-Tropsch synthesis. Areas of investigation requiring further research are identified.

Progress in Ion Transport Membranes for Gas Separation Applications

This chapter describes the evolution and advances of ion transport membranes for gas separation applications, especially separation of oxygen from air. In partnership with the US Department of Energy (DOE), Air Products and Chemicals, Inc. (Air Products) successfully developed a novel class of mixed ion–electron conducting materials and membrane architecture. These novel materials are referred to as ion transport membranes (ITM). Generically, ITMs consist of modified perovskite and brownmillerite oxide solid electrolytes and provide high oxygen anion and electron conduction typically at high temperatures driven by an oxygen potential gradient without the need for external power. The partial pressure ratio across the ITM layer creates the driving force for oxygen separation.

Mixed conducting ceramic membranes for gas separation and reaction

Abstract The development of dense ceramic membranes for separating and reacting various gaseous components has been under intense investigation during the past several years. Such applications include the separation of oxygen from air, the partial oxidation of methane and other hydrocarbons, and the separation of hydrogen from synthesis gas or other hydrogen-containing process streams. The US Department of Energy is currently sponsoring major efforts in the development of these membranes for advanced power and fuels production applications. This article provides an overview of the current programme. Particular emphasis is placed on the separation of oxygen from air.

Large-pore NiMoAl2O3 catalysts for coal-liquids upgrading☆

Abstract A novel method that can produce large-pore unimodal or bimodal alumina extradates was developed. Since the method used to produce the larger-diameter pores does not involve a steaming or sintering process, the resultant supports have high surface areas, ~350 m 2 /g. Also, the technique allows catalysts with widely varying pore structures to be prepared while holding all preparation variables constant except for the extent of mixing used during preparation of the extrusion batch. These experimental supports were used to prepare NiMo catalysts for upgrading coal liquids. The results of an initial batch-screening test suggest that the resulting bimodal catalysts are more effective for upgrading coal liquids than the corresponding unimodal catalysts.

Deactivation phenomena by site poisoning and pore blockage: The effect of catalyst size, pore size, and pore size distribution

Abstract The problem of catalyst deactivation by active site poisoning and pore blockage is analyzed. The effect of catalyst size, average pore size, and pore size distribution on the phenomenon of deactivation is investigated for two simple pore structure models, i.e., the “single pore” and “parallel bundle of pores” models. It is shown that the overall catalytic behavior and performance strongly depend on the catalysts physical properties, such as its size, pore size, and pore size distribution. The mathematical models studied here are admittedly only oversimplified analogs of the complex physicochemical phenomena occurring during realistic industrial processes. The main qualitative features, however, of the overall catalytic behavior predicted here are the result of basic and strongly counteracting, underlying physicochemical processes. As such, the types of catalytic behavior described are not strongly dependent on the particular kinetic and diffusion models employed but are closely associated with macromolecular catalytic reaction systems that deactivate by simultaneous active site coverage and pore blockage.

Catalytic hydrotreatment of coal-derived residua

Abstract An investigation was conducted to determine the activities of various coal-liquefaction residua during catalytic hydrotreatment. Residua produced at low- and high-severity coal-liquefaction conditions were employed, as well as a nondeashed residuum produced at low-severity conditions. All experimental runs were performed in a continuous-flow hydrotreating unit using Shell 324M catalyst. Except for hydrogenation activity, catalyst activity declined with a typical S-shaped deactivation curve. The properties of the spent catalysts do not depend significantly upon prior processing of the feedstock; however, the prior processing history of the feedstocks affected their reactivity and the rate of catalyst deactivation. The results indicate beneficial effects of conducting coal liquefaction at low-severity conditions and of product deashing prior to catalytic hydrotreatment.

Catalysts for Fischer-Tropsch

The slurry-phase Fischer-Tropsch (F-T) process has attracted considerable attention recently. The process can make liquid fuels by reacting hydrogen-lean synthesis gas produced from modern energy-efficient gasifiers. continuing assessment of Fischer-Tropsch Synthesis (FTS) has a high priority within an indirect liquefaction program, a part of the liquid fuels program sponsored by the U.S. Department of Energy (DOE) and executed by the Pittsburgh Energy Technology Center (PETC). Funding for the indirect liquefaction program in 1990:0090 is anticipated to be about

Early Entrance Coproduction Plant - the Pathway to the Commercial CTL (Coal-to-Liquids) Fuels Production

8.5 million compared to

DOE INDIRECT COAL LIQUEFACTION PROGRAM —AN OVERVIEW

6.6 million in 1989 and a like amount in the year before. The studies within the program are conducted by industry, universities, national laboratories and in-house PETC research and development. This article reviews preparation and properties of iron-based catalysts, including recent patent activities and in-depth process analysis of slurry-phase FTS. The review provides an analysis of Fischer-Tropsch catalyst research and development trends and describes options to increase selectivity for iron-based catalysts in a slurry phase.