The considerable recent interest in the conversion of stranded methane into transportable liquids as well as fuel cell technology has provided a renewed impetus to the development of efficient processes for the generation of syngas. The production of syngas (CO/H2), a very versatile intermediate, can be the most expensive step in the conversion of methane to value-added liquid fuels. The catalytic oxy reforming of methane, which is an energy-efficient process that can produce syngas at extremely high space–time yields, is discussed in this Review. As long-term catalyst performance is crucial for the wide-scale commercialization of this process, catalyst-related studies are abundant. Correspondingly, herein, emphasis is placed on discussing the different issues related to the development of catalysts for oxy reforming. Important aspects of related processes such as catalytic oxy-steam, oxy-CO2, and oxy-steam-CO2 processes will also be discussed.

Energy‐Efficient Syngas Production through Catalytic Oxy‐Methane Reforming Reactions

This review compares various alternate fuels and value-added products from conversion of carbon dioxide such as simple molecules to higher hydrocarbon fuels and polymers. Different methods of activation are summarized that lead to different products. We summarize the advantages and disadvantages of different methods of conversion of carbon dioxide. An overall summary is given at the end of the review that discusses future approaches and promising approaches.

Thermal, electrochemical, and photochemical conversion of CO2 to fuels and value-added products

Steam cracking is a well-established commercial technology for ethylene production. Despite decades of optimization efforts, the process is, nevertheless, highly energy and carbon intensive. This r...

Recent Advances in Intensified Ethylene Production—A Review

Hydrogen production has been a matter of great importance in the last decades, but a renewed interest in its production processes has emerged recently driven by the spectacular advances in fuel cell technology. This review provides a comprehensive overview of the state‐of‐the‐art on reforming technology applicable to the development of small scale reformers. It considers some general aspects on hydrogen production technologies including the current production status, the future needs, and the advantages of decentralized hydrogen production vs its centralized generation in large capacity plants. Conventional and novel technologies are presented together with the new trends in research and development activities.

New Trends in Reforming Technologies: from Hydrogen Industrial Plants to Multifuel Microreformers

The catalytic reforming of hydrocarbons in a microreformer is an attractive approach to supply hydrogen to fuel cells while avoiding storage and safety issues. High-surface-area catalyst supports must be stable above 800°C to avoid catalyst coking; however, many porous materials lose their high surface areas below 800 °C. This paper describes an approach to fabricate macroporous silicon carbonitride (SiCN) and silicon carbide (SiC) monoliths with geometric surface areas of 10 5 to 10 8 m 2 per m 3 that are stable up to 1200 °C. These structures are fabricated by capillary filling of packed beds of polystyrene or silica spheres with low-viscosity preceramic polymers. Subsequent curing, pyrolysis, and removal of the spheres yielded SiCN and SiC inverted beaded monoliths with a chemical composition and pore morphology that are stable in air at 1200°C. Thus, these structures are promising as catalyst supports for high-temperature fuel reforming.

Tailored Macroporous SiCN and SiC Structures for High‐Temperature Fuel Reforming

This manuscript describes the use of the tapered element oscillating microbalance (TEOM) to monitor the formation of elemental carbon under extreme reaction conditions, specifically the steam reforming of methane at 650°C and operating pressures as high as 200 psig. Since the TEOM reactor passes the entire feed stream over all of the catalyst bed under a variety of process conditions at high temperatures and high pressures, one can get an accurate assessment of the relative change in catalyst mass, and therefore, carbon deposition with time on stream. In particular, the studies clearly show the accelerated rate of carbon deposition on Ni catalysts which occurs at elevated pressures during steam methane reforming.

Studying carbon formation at elevated pressure

Carbon dioxide, a major greenhouse gas, can be used as a source of carbon. Conversion of CO2 into organic compounds has been studied intensively. For example, ethane catalytic dehydrogenation [Equation (1)] offers an attractive route for converting CO2. Firstly, the coke-formation problem, particularly troublesome in the steam-cracking industry, can be solved by treating the coke with CO2 to generate CO over the catalyst. In addition, CO2 can act as a medium for supplying heat to the endothermic dehydrogenation reaction. 4] Furthermore, the products from Equation (1), C2H4 and CO, are precursors for olefin/CO copolymerization reactions. By varying the feedstock ratio (C2H6/CO2) in the reaction, different ratios of the products (C2H4/CO) can easily be obtained for the specific copolymerization process. Hence, the dehydrogenation of ethane in the presence of CO2 is an ideal feedstock for any process involving ethylene carbonylation with an additional benefit of recycling the greenhouse gas.

Studies on Dehydrogenation of Ethane in the Presence of CO2 over Octahedral Molecular Sieve (OMS‐2) Catalysts

A process for hydrotreating a hydrocarbon feedstock, such as light cycle oil, using a catalyst composition containing a hydrogenation/dehydrogenation component and an acidic solid component including a Group IVB metal oxide modified with an oxyanion of a Group VIB metal. The hydrotreating process removes contaminants, such as sulfur and/or nitrogen, from the feedstock.

Process for hydrotreating

There is provided a process for converting methane to hydrocarbons having at least two carbon atoms. The process involves contacting methane with an oxidizing agent, such as oxygen, at a relatively moderate temperature of less than about 700° C. and a relatively high pressure of greater than about 20 atmospheres.

Process for direct oxidative conversion of methane to higher hydrocarbons at high pressure and moderate temperature

A mixture of organic compounds comprising a major amount of liquid hydrocarbons, mostly aromatic, is formed by the direct partial oxidation of methane in the presence of a ZSM-5 catalyst. The reaction conditions are substantially the same as those required for the direct homogeneous partial oxidation to methanol. However, liquid hydrocarbon formation depends on the presence of a small amount of an impurity such as propane or propylene in the feed; in the absence of such, only methanol is formed. With such modifier present, controls of reaction parameters, e.g., temperature, permits synthesis of both methanol and liquid hydrocarbons in desired proportions. Properly processed natural gas can serve to provide methane and at least part of the reaction modifier.

Daniel J. Martenak

Papers

Studying carbon formation at elevated pressure

Studies on Dehydrogenation of Ethane in the Presence of CO2 over Octahedral Molecular Sieve (OMS‐2) Catalysts

Process for hydrotreating

Process for direct oxidative conversion of methane to higher hydrocarbons at high pressure and moderate temperature

Conversion of methane