Steam demonstrator power plant

Figure 12. Steam reformer under construction for 4.8-MW fuel cell demonstrator power plant (to be operated by Con Edison in New York City)...

Although natural gas feedstock currently is preferred by some demonstration plants, alternative fuels, such as light distillates, coal gas. and fuel-grade methanol may be used. Methanol can be steam reformed at relatively low temperatures and. for this reason, can be adapted to smaller, transportable fuel-cell power plants of the type desired for certain military and commercial gear. 

Recent very successful demonstrations of the high efficiencies that can be achieved with combined cycle gas turbine-steam turbine power plants using pressurized, fluidized... 

In this demonstration plant, the boiler feedwater can be preheated by geothermal heat if available. Depending on the availability and temperature of the geothermal heat in the area, the geothermal plant s design would vary. If the groundwater temperature exceeds 150°C (302°F), a "flash steam" power plant would be used, and if it is between 100 and 150°C (212 and 302°F), a "binary cycle" power plant would be used. 

Currently, the stationary power market penetration of the fuel cell is based on reduced local pollution rather than superior performance. Indeed the internationally demonstrated Ballard fuel cell bus generates more pollution from the power plant stack which generates its hydrogen supply from an inefficient incomplete electrolyser, than it saves by emitting steam from its exhaust. The industry has to rescue itself from this untenable position. 

A look at the use of different reactor types demonstrates the dominant role of the LWR line in commercial electricity production. From 428 nuclear power plants operating worldwide in 1996 to produce 363 GW(e) or 17 % of the international electricity supply -plus 62 units under construction to produce 55 more GW(e) - 342 plants are LWRs, 249 PWRs and 93 BWRs, for a total of 311 GW(e) [27]. And the trend to larger power units was observed. Not more than 5 GW(th) of global nuclear power are presently employed to supply hot water and steam, mostly in Canada, China, Kazakhstan, Russia, and Ukraine [25]. 

Two different fuel cell power plants have been tested. The alkaline type demonstrated good performance during its trouble-free operation, but due to repeated repair work, it was later stopped. Since 1993, a PAFC power plant of 79 kW(e) is in operation which also allows cogeneration of 180 °C heat. It is fueled with either hydrogen or natural gas to be converted to hydrogen in an upstream steam reformer. A 10 kW PEM fuel cell is operating a standard electric fork lift truck... 

A wood-fired power plant is included in the PEF system to produce electricity from the solid fuel produced on the dry-land Energy Plantation. Some of the various elements included in the power plant subsystem and the model are shown in Figure I. The power cycle modeled is a conventional steam Rankine cycle as is used in coal-fired and nuclear power plants, in keeping with the decision that the model should represent "state-of-the-art" equipment which would be readily available for a demonstration system. The system components are similar to those that would appear in a simple coal-fired power plant with the additional equipment to dry and screen the fuel before it enters the boiler. 

Cofiring woody biomass in coal-fired boilers is performed differently depending upon the type of boilCT in PC boilers, woody biomass is typically injected separately from the coal unless vray low percentages of woody materials are used (e.g., <5 percent by mass, or <2 percent by heat input). This separate injection is based upon adding flexibility to the boiler operations. Demonstrations have shown that separate injection permits concentrating the woody biomass in a single location to optimize NOx reduction. Additionally, separate injection facilitates recovery of boiler steaming capacity that can be lost when wet coal is received by the power plant. In cyclone boilers the woody biomass is typically blended with the coal and introduced into the boiler with the coal [20]. In order to evaluate these uses of woody biomass as an opportunity fuel, case studies are employed as described below. 

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