Table of Contents
What is difference between air preheater and economizer?
economizer requires lesser space and surface area compared to the air heater due to the high tube side water heat transfer coefficient and larger U compared to the air heater. NOx formation is much more with an air heater due to the higher combustion temp with air preheat.
Why economizer is used in thermal power plant?
A common application of economizers in steam power plants is to capture the waste heat from boiler stack gases (flue gas) and transfer it to the boiler feedwater. This raises the temperature of the boiler feedwater, lowering the needed energy input, in turn reducing the firing rates needed for the rated boiler output.
What is the purpose of superheater in a boiler?
Superheaters and reheaters are specially designed to increase the temperature of the saturated steam and to help control the steam outlet temperature. They are simple single-phase heat exchangers with steam flowing inside and the flue gas passing outside, generally in the cross flow.
What is a superheater in boiler?
The superheater heats steam above the saturation temperature for a particular boiler pressure. Superheater tubes have steam on one side and hot combustion gases on the other.
What is the purpose of economiser?
An economizer is a mechanical device used to reduce energy consumption. Economizers recycle energy produced within a system or leverage environmental temperature differences to achieve efficiency improvements.
What is the function of superheater in the boiler Mcq?
Explanation: Function of the superheater is to increase the temperature of steam above its saturation temperature.
What is the sequence of superheater economiser and air preheater?
Sequence of superheater, economiser and air preheater is maintened for achieving required heat transfer between flue gases and steam in superheater, feed water in economiser and air in APH. Superheater is the heat exchanger where steam is superheated so placed in such place where maximum heat transfer can take place.
What is the purpose of superheater in thermal power plant?
Superheater : Purpose of the Superheater in thermal power plant is to convert the saturated steam into supersaturated steam. Final Superheater output will be into main steam pipe which carries the superheated steam to turbine rotor for power generation.
Why is the steam reheater placed after the superheater?
At low pressure, the steam has poor cooling ability: to address this, the reheater is usually positioned after the superheater where the temperature of the flue gas is relatively low and principally relies on convection heat transfer.
What type of heat is absorbed by a superheater?
The heat absorbed by the superheater is principally in the form of radiation when the temperature of the superheated steam is controlled by the ratio of furnace water flow to fuel input.