Question

State the importance of using superheaters and reheaters in standalone steam power plants and in combined cycle power plants. Make a short comparison

please compare them to each other.

Answer 1

Stand-alone plants are installed because of two major reasons one is the isolated geographical area where power transmission is not feasible, and the second one is to reduce dependency on non-renewable sources.

As in Stand-Alone stream power plants concentrated solar power is used to generate electricity by heating water converting into the stream and using a turbine to let generated stream expand resulting in power generation.

Like traditional thermal/coal power plants where superheater and reheater are used to increase efficiency and output power, the same can be implemented in the Stand_Alone stream power plant too by improving power generated.

Currently, present solar boilers are only able to generate steam of about 700° F. at about 700 psi. This is due to the limitations of the oils used in solar thermal arrays for transporting thermal energy from the solar array to the boiler. However, hardware normally used in power generation plants, including plumbing and expansion turbines, are often designed to operate with steam at pressures well over 1000 psi and temperatures well over 1000° F. Thus, in some embodiments, higher temperature but lower pressure steam from a Heat Recovery System Generator, such as those commonly used in combined cycle systems, can be used to further superheat the steam in a solar thermal system before it is delivered to the expansion turbine. So to fully utilize the equipment like a turbine and other Superheater and Reheaters are used in Standalone power plants to increase pressure and temperature. ie:_

A combined-cycle power generation system can be combined with a solar Rankine power generation system such that the integrated system has improved power generation efficiency over two stand-alone systems. Relatively high temperature, low-pressure reheat from the combined cycle power generation system can be used, through. Like, a superheater, to raise the temperature and pressure of a working fluid in a solar Rankine power generation system. The resulting integrated system has enhanced efficiencies as compared with stand-alone systems.

Because of low heat generation in Standalone steam power plant, the extent and demand to include regulator and superheater is high to use other parts at full potential while in the case of combined cycle we generally use it to generate more power and to keep operating the plant at the peak point.

Standalone stream power plants as cannot operate 24x7 we cannot reliy on it for all time and for pick power loading while combined can be. In this regard if Standalone stream power plant if coupled with combined power cycle one can reduce dependenncies on non-renewable sources as partly power can be supplied by Standalone power plant.