Fuel small-scale units

Large cogeneration units have had a long and successful operating history and are more durable than small-scale units. The larger systems operate at about 35% electrical conversion efficiency and 45% heat conversion efficiency. This means that 80% of the energy in the fuel is converted to heat or electricity. 

For small-scale units providing hydrogen for fuel cells, the choice of the optimal technology may be dictated by parameters such as simplicity and fast... 

The benefits and feasibility of hybrid systems have been established with conceptual studies and small-scale demonstrations fueled with natural gas. If large-scale, greater than 100-MW, fuel cell/turbine hybrid systems are to become a reality a reduction in fuel cell costs and scalability to larger units is required. The SECA program demonstrated 3 to 10 kW SOFC systems with costs of less than 800/kW in 2005. 

In Japan, being completely dependant on fossil fuels imports, a long tradition exists in developing stationary and mobile fuel cell applications. Programs funded by the NEDO and METI departments have already resulted in hundreds of small scale micro Combined Heat and Power Units as well as fuel cell vehicles running in road demonstrations [4]. 

The publicly-funded fuel cell research program started in 1985, with the main activities performed at the Energy research Centre ofthe Netherlands (ECN). Between 1985 and 2001, about 100 million was invested by mixed public-private funds in the development of fuel cell and hydrogen energy. The objectives ofthe Dutch fuel cell programs were initially oriented to the application of coal gas in MCFC based systems. The MCFC activities were terminated in 2001, after an evaluation failed to indicate its commercial viability with natural gas. Afterwards, the activities shifted to SOFC and PEM technology for high efficient conversion of natural gas in small-scale decentralised units. 

Ehrlich C, Noll G, Kalkoff W-D (2007) Determining PM-emission fractions (PM10, PM2.5, PM1.0) from small-scale combustion units and domestic stoves using different types of fuels including biofuels like wood pellets and energy grain. In DustConf 2007, Maastricht. http //www. dustconf.com/CLIENT/DUSTCONF/UPLOAD/S4/EHRLICH. PDF, Accessed 5 Feb 2012... 

Nowadays, the most common small-scale application of hydrogen is the use in residential or mobile fuel cell systems. Special requirements of this application are compact design, integrated CO-removal, high energetic efficiency, quick start-up and fast transient behavior. The proposed solutions comprise unit-operation-based concepts as well as multifunctional, micro-structured reactors. 

Figure 9.10 Flow chart of an ethanol fermentation plant. (Source United States. National Agricultural Library Office of Alcohol Fuels Solar Energy Research Institute. Fuel from Farms A Guide to Small-Scale Ethanol Production. Golden, Colo. Technical Information Office, Solar Energy Research Institute, 1982 published at www //dnr.state.Ia.us.)...

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