Reversible Solid Oxide Fuel Cell Technology for Hydrogen/Syngas and Power Production

Abstract

IntroductionWorld energy consumption is projected to grow by about 56% from 2010 to 2040 (from 524 quadrillion to 820 quadrillion British thermal units (Btu)) with consumption increases from all fuel sources (fossil, nuclear, and renewable) and fossil fuels expected to continue supply much of the energy used worldwide (almost 80%) [1]. As use of fossil fuels is projected to increase, world energyrelated CO 2 emissions will grow from 31 billion metric tons in 2010 to 45 billion metric tons in 2040, a 45% increase [1]. Thus, it is expected that future energy systems should be fuel-flexible (flexibility) (to facilitate integration with any type of energy sources) and environmentally compatible (compatibility) (to reduce CO 2 emissions). In addition, such systems should have the characteristics of capability (useful for different functions), adaptability (suitable for various applications and adaptable to local energy needs), and affordability (competitive in costs) (Figure 16.1). Reversible solid oxide fuel cells (RSOFCs), being developed for hydrogen/syngas production and power generation, potentially have all those desired characteristics and, therefore, can serve as a base technology for green, flexible, and cost-competitive future energy systems [2]. This chapter provides an overview of the RSOFC, discusses its hydrogen/syngas production and power generation operations, and reviews the status of the technology and its applications. Reversible Solid Oxide Fuel Cell Overview Operating PrinciplesA RSOFC is a device that can operate efficiently in both fuel cell mode for power generation and electrolysis mode for chemical production. Thus, in fuel cell

Direct Conversion of Methane to C2Hydrocarbons in Solid-State Membrane Reactors at High Temperatures

“…Renewable energy is rapidly becoming the most flexible and accessible form of electricity in the world, and the electrification of chemical processes is one of the most encouraging and hopeful transition paths to a low carbon footprint and the ecological production of chemicals and fuels. 110,111 Green/sustainable electrochemical science and technology play a major role within industry and society in providing greener, more sustainable, and cleaner technologies that have many applications, such as synthesis of materials, recycling resources, and generating and storing energy power. 110−113 Therefore, exploring such technologies for C 2 production, such as ethylene, could be a promising alternative.…”

“…In fuel cell mode, fuel conversion takes place simultaneously to the power generation, whereas in the electrolysis mode, energy is supplied to the system to sustain nonspontaneous reactions. 108,110,149,150 As a prototype SSMR, solid oxide fuel cells (SOFCs) are the technological platform for new reactor designs, including the solid oxide electrolyzer cell (SOEC), due to the great development of such devices in the last decades. In the electrolysis mode, a SOEC produces chemicals, usually hydrogen.…”

“…Issues concerning stability are progressively b e i n g o v e r c o m e a s d e s c r i b e d i n s e v e r a l r eports. 105,108,110,118,151,152 The reversibility of such SSE reactors provides a possibility of direct utilization of oxygen ions to in situ electrochemically oxidize CH 4 into C 2 H 4 (reaction 12). Therefore, the electrochemical conversion of CH 4 into C 2 H 4 in the SSE reactor would be successfully achieved, demonstrating economic and sustainable potential if this process exploits the available exhaust heat stream and renewable electrical energy.…”

“…Therefore, the electrochemical conversion of CH 4 into C 2 H 4 in the SSE reactor would be successfully achieved, demonstrating economic and sustainable potential if this process exploits the available exhaust heat stream and renewable electrical energy. 105,[108][109][110]117 In addition to the O 2− conductor SSE, different configurations of SSMR using H + conductor SSE, MIEC (with O 2− transport), and MPEC have also been investigated to convert CH 4 to C 2 . The use of MIEC and MPEC in SSMRs eliminates the use of electron-conducting electrodes, and studies have reported C 2 yields exceeding 10%.…”

“…Both operating modes prevent the explosion of the reaction mixture since CH 4 and O 2 are separated by the electrolyte. 110,118,123,176 Therefore, in optimized reactional conditions, in an SSE membrane reactor, there is the possibility of combining the electrochemical increase in the product selectivity, better control over the reaction path, and simultaneous generation of electrical energy.…”