At a Glance

In our previous blog, we have discussed steam-generating equipment. In today’s blog, we will discuss other equipment of steam power plant such as condenser and feedwater heaters.

Condenser

Before discussing the condenser, let’s talk about condensation cause the whole working principle thing of condensers depends upon this.

Condensation is the change process or causes to change from a gas or vapor to a liquid.

So after reading the condensation process, you might have got the idea of condensers working. Let me explain to you in detail.

After expanding the steam through prime movers, exhaust steam goes through the condenser, which condensates the exhaust stream and the air. In the condenser, the exhausted steam is converted into liquid.

This recovery of exhaust steam in the condenser reduces the make-up feed water requirement from 100% exhausted to the atmosphere to about 1-5% and reduces the water treatment plant’s capacity.

You might have been confused why she even talked about feed water requirement while explaining condenser, which means the purpose behind all this. So the thing is that steam power plants components work in a close loop cycle. So to expand the steam on the turbine, we need the feed water in the boiler to generate the steam. Using the condenser, we can reduce the intake from the water source boiler and continue the close loop cycle.

Let’s discuss what exactly the condenser is

A condenser is a chamber where gas can contact a cooled surface and change phase to liquid removes the latent heat from exhaust steam.

According to working condenser is classified into two types:

1. Jet/ contact condenser.
2. Surface condenser.

The basic difference between the jet/ contact condenser and surface condenser is that:

In a jet/ contact condenser, the exhaust steam mixes with the cooling and the water. As a result, the condensate and cooling water temperature are the same when leaving the condenser.

In the surface condenser, the exhaust steam and cooling water do not mix. Instead, the water is circulated through a nest of tubes, and the heat is transferred by convection.

In the convection process, heat is transferred by the movement of heated fluid. In the case of condensers, it is exhaust gases.
The condensate temperature is higher than the temperature of cooling water, and condensate is recovered as feed water to the boiler.

Advantages of jet/ contact condenser over surface condenser are that it has-

1. Low initial cost.
2. Requirement of floor area.
3. Maintenance charges are also low.

But jet condensers have some serious disadvantages also for that this condenser is only used for small and medium-scale power plants, some serious disadvantages of jet condensers are –

1. The condensate output for the outlet is wasted.
2. The power required for pumping the water is high.

Feedwater heaters

Feedwater heaters are the heater that heats the feed water for the boiler using wastage flue gases.

In scientific language, the feedwater heater is used to heat the feedwater utilizing bled steam before being supplied to the boiler.

So what is the necessity of feedwater heaters if we already have the boiler to generate the heat?

1. Overall, plant efficiency is improved.
2. Thermal stresses due to cold water entering the boiler drum are avoided.
3. A feedwater heater increases the quantity of steam produced by the boiler.
4. Dissolved oxygen and carbon dioxide, which would otherwise cause boiler corrosion, are removed during the healing process.
5. Some other impurities are carried by steam and condensate, which causes corrosion in the boiler, and condensers are precipitated outside the boiler.

According to the construction, feedwater heaters can be classified into two types:

1. Open/contact heaters.
2. Closed/ surface heaters.

The available heaters are basically constructed to remove condensate gases from water and steam and raise feed water temperature. Such types of heaters are also called deaerator.

In closed / surface feedwater heaters, it consisted of closed-shell in which there are tubes or coils through which either steam or the water is circulated horizontally or vertically.

This was part 1 for the types of equipment of a steam power plant. In the next part, we will discuss some other elements prime movers, spray ponds, and cooling towers, so stay tuned with the website for more updates.