Table of Contents
- 1 Why do we preheat the combustion of air?
- 2 How is combustion air preheated?
- 3 What is APH in thermal power plant?
- 4 What is combustion air?
- 5 Why is combustion air important?
- 6 How does air react with combustion?
- 7 What is the purpose of economizer in thermal power plant?
- 8 What does regenerative air preheater consists of?
Why do we preheat the combustion of air?
The main objective of preheating the air is to enhance the thermal efficiency of heating processes. In boilers, preheated air recovers its heat from the boiler’s flue gas. This leads to the improved boiler thermal efficiency brought about by the lessened level of heat loss in the boiler’s gas.
How is combustion air preheated?
Introduction. Heating combustion air can raise boiler efficiency about 1\% for every 40F in temperature increase. The most common way to preheat the air is with a heat exchanger on the flue exhaust. The heat exchanger can be either air-to-air or air-to-liquid-to-air.
Why economiser and air preheaters are used in steam power stations?
It is designed to save energy by using the exhaust gases from the boiler to preheat the cold fluid, mainly water, that is used to fill it. An increase in fuel prices means that power plants are having to increase the boiler efficiency and this is made possible with the assistance of Economisers.
What is APH in thermal power plant?
Air Preheaters (APH) is the Shell and tube type Heat Exchangers used for preheating the air which is fed to the boiler or furnaces/kilns for combustion of fuels. Air Pre heater’s primary objective is to extract the waste heat from the flue gases leaving the boiler.
What is combustion air?
What is combustion air? Combustion air is a source of oxygen needed to burn fuel such as natural gas or liquid propane (LP). You can’t produce a flame in a furnace without proper combustion air. The image above shows the combustion air as a vent in the garage to pull air from the attic.
How much combustion air does a furnace need?
A furnace must be supplied a specific amount of fresh air per cubic foot of gas burned. To burn 1 cubic foot of gas, approximately 1,000 Btu for natural gas, requires 10 cubic feet of air for perfect combustion (Figure 2).
Why is combustion air important?
Excess air is supplied to the combustion process to ensure each fuel molecule is completely surrounded by sufficient combustion air. As a burner tune-up improves the rate at which mixing occurs, the amount of excess air required can be reduced.
How does air react with combustion?
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
Why economiser 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 economizer in thermal power plant?
Function of economiser in thermal power plant is to recover some of the heat from the heat carried away in the flue gases up the chimney and utilize for heating the feed water to the boiler.
What does regenerative air preheater consists of?
The best explanation: This type of air preheater consists of a rotor which turns about 2 to 3rpm. The rotor is filled with thin corrugated metal elements. Hot gases pass through one half of the heater and air through the other half.