Efficiency of power plants

How many kilograms of coal could be saved if we were to increase the average efficiency of power plants by 1% to 36% ... 

The removal of mineral matter content including the pyritic sulfur improves the efficiency of power plant it could provide a reduction of up to 40% in SO2 emissions and about 5% in carbon dioxide emissions (Breeze, 2005 lEA, 2008). 

Concepts of nuclear reactors cooled with water at supercritical pressures were studied as early as the 1950s and 1960s in the US and Russia. After a 30-year break, the idea of developing nuclear reactors cooled with supercritical water (SCW) became attractive again as the ultimate development path for water cooling. This statement is based on the known history of the thermal power industry, which made a revolutionary step forward from the level of subcritical pressures (15—16 MPa) to the level of supercritical pressures (23.5—35 MPa) more than 50 years ago with the same major objective as that of supercritical water-cooled reactors (SCWRs) to increase thermal efficiency of power plants. The main objectives of using SCW in nuclear reactors are (1) to increase the thermal efficiency of modem nuclear power plants (NPPs) from 30—35% to about 45—50% and (2) to decrease capital and operational costs and, hence decrease electrical energy costs. 

The recirculation of combustion products into the combustion zone is one of the most studied and widespread methods of reducing nitrogen oxides, currently widely used in the combustion technology the admixing of 20% of the recycle gas to the blow air can halve the yield of nitrogen oxides [296]. The maximum flame temperature is reduced thereby by nearly 200 °C. Since the introduction of recycle gas into the combustion chamber results in a decrease in the temperature of the exhaust gas and in a reduction in the efficiency of power plants by about 0.02—0.03% per 1% recycle gas added, it is believed that, imder the condition of stable combustion, flue gas recirculation should be limited to 20—30% [296]. 

CAT An abbreviation for carbon abatement technology. CAT is a group of technologies used to improve the efficiency of power plants with low-carbon alternatives such as biomass. See CARBON CAPTURE AND STORAGE. 

Cr ferritic-martensitic steels are on the borderline of the protective situation with respect to oxidation corrosion at 650°C [1, 2], Austenitic steels and nickel-based alloys are potential candidates for increasing the steam temperatures and thus the efficiency of power plants. However, they are more expensive, have higher coefficients of thermal expansion and show lower heat conductivity, which are the significant drawbacks for their use as heat exchanger tubes. 

Advances in the steam conditions that are used in plants have played a key role in meeting increased electricity demands while reducing pollutant emissions and keeping up with global trends for improved efficiency of power plants. 

In 1997, a Program Research and Development Announcement (PRDA) was issued by the Department of Energy for conceptual feasibility studies of high-efficiency fossil power plants (HEFPPs). The terms of the conceptual power plant must be less than 20 MW in size, operate on... 

The efficiency of the plant with the alternate interface is at least 1.5% higher. The increase is a consequence of better matching of heat source temperature to HTE plant heat requirements. The power sources and sinks that combine to determine the overall efficiency are shown in Table 3. It is noted that substituting combustion of a synthetic organic created from the plant hydrogen stream in place of electric heating might raise the efficiency of the Alternate Interface plant another 1%. 

In addition to co-firing, there are three other types of biomass electricity-generation systems direct-fired, gasification, and modular. Of these, the most commonly used is direct-fired. In this system, biomass fuel is burned in a boiler to produce high-pressure steam, which then drives turbines to produce electricity. The drawback to these types of power plants is that they tend to be small scale and are not very efficient. Costs also tend to be relatively high, at nine cents per kilowatt-hour, versus only 2.1 cents per kilowatt-hour for some co-fired plants.31... 

Example 5.1 A central power plant, rated at 800,000 kW, generates steam at 585 K and discards heat to a river at 295 K If the thermal efficiency of the plant is 70 percent of the maximum possible value, how much heat is discarded to the river at rated power ... 

A steam power plant operates on the cycle of Fig. 8.4. For one of the following sets of operating conditions, determine the steam rate, the heat-transfer rates in the boiler and condenser, and the thermal efficiency of the plant. 

At 1-10 W (watts), fuel cells could be used as battery replacements at 100 W to 1 kW, fuel cells could find military applications which require lightweight portable power sources for communications and weapon power at 1 - 10 kW, fuel cells could supply power to residential buildings and serve as auxiliary power units in vehicles and trucks. At higher power levels, the solid oxide fuel cell (SOFC) could be an effective approach for the distributed power generation and the cogeneration (i.e., combined heat and power). Above 1 MW, the SOFC could be integrated with a turbine power plant to improve the overall efficiency of power generation and reduce emissions. ... 

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