Albritton Interiors

Increasing Boiler Efficiency With Economizer/Preheater Combos

A biomass plant produces electricity and heat by burning biomass in a boiler. In a coal plant water is turned to steam which drives the turbine generators to produce electricity. For both these plants, boiler efficiency is the key and plays an important role. The AIC Heat exchangers plays a major role in temperature setting.

Hence, in order to enhance the efficiency of boilers, economizers and preheaters are provided. They help to recover heat from the flue gases. Together they provide up to 20% of an increase in efficiency. Therefore, the designers provide both rather than just using an economizer.

Let us see how these Economizers and Preheaters play a vital role in maximizing the efficiency of boilers in coal and biomass plants.


Economizers are those heat exchanging devices that heat fluids up to the normal boiling point and not usually beyond that. They recover the wasted heat from the boiler system. With the help of flue gas, they heat the fluid and direct it to the water system (the feed water). They save energy by using the gases exhausted from the boiler for preheating the cold water used as feed.

A professional installation of a well-designed heat exchanger design can reduce the fuel cost up to 5 – 10 percent, which is indeed beneficial.

Air Preheaters

Air Preheaters are one of the heat exchange devices provided in boilers to preheat the combustion air. They use a combination of steam, water, flue gas or thermal oil for this process. It is simple to understand that when the boiler has to put in less effort to produce the similar amount of energy if the combustion process is more efficient. When the air entering in is pre-heated this way, it requires less energy from the boiler and hence increases efficiency.

You can also say that such air Preheaters go an extra mile to increase the incoming fluid temperature and save energy for the boilers.

Types of Air Preheaters:

Recuperative Preheaters – Used for boilers of medium and small range.

Regenerative Preheaters – Used for high-capacity boilers, producing about 600 tonnes per hour or higher than that.

The Duo, Economizers and Preheaters Maximize Efficiency

It is already clear that to maximize the efficiency of boilers, both economizers and Preheaters are equally important. Using one at a time won’t be beneficial.

Currently, there has been a considerable increase in the demand of electricity throughout the world. This has resulted in increased size of the power plants. Hence, the modern day power plants are required to be more efficient in providing energy for various purposes and hence their boilers have to stand out. We are well aware that availability of some resources cannot last forever e.g. Coal. Thus using the duo efficiently in a custom made design will keep the coal and biomass plants ahead in the competition.