How does a feedwater heater work?

How does a feedwater heater work?

The feedwater heaters are constructed of tubes through which feedwater is passed. The water is heated by steam from the turbine. The steam being at a higher temperature condenses on the outside of the tubes and gives up its latent heat to the feedwater. The temperature of the feedwater is thus increased.

How does a closed feedwater heater work?

Closed feedwater heaters are typically shell and tube heat exchangers where the feedwater passes throughout the tubes and is heated by turbine extraction steam. These do not require separate pumps before and after the heater to boost the feedwater to the pressure of the extracted steam as with an open heater.

What is the effect of adding more feedwater heaters in power plants?

The higher the feedwater temperature, the less fuel is required to produce the steam used to produce electricity in the steam turbine. However, steam is extracted from different locations on the steam turbine to heat the feedwater, which increases the plant heat rate.

What is HP heater in power plant?

HP heaters are used for heating the feed water, which will contribute in increasing cycle efficiency as well as reduction in fuel consumption.

What is a low pressure feedwater heater?

Low pressure (LP) feedwater heaters are basically simple straightforward ‘tube and shell’ heat exchangers, with the condensate passing through the tubes and the bled-steam being admitted to the shell. The omission of an isolating steam valve prompted the development of improved methods of preventing heater flooding.

What effect does the heating of feedwater by steam bled from the turbine has on the Rankine Cycle?

5. What effect does the heating of feedwater by steam ‘bled’ from the turbine has on the Rankine Cycle? Explanation: The heating of feedwater by steam ‘bled’ from the turbine, known as regeneration, carnotinises the Rankine cycle. 6.

What do you understand by a steam trap and a closed feedwater heater?

In an ideal closed feedwater heater, the feedwater is heated to the exit temperature of the extracted steam, which ideally leaves the heater as a saturated liquid at the extraction pressure. A trap allows the liquid to be throttled to a lower pressure region but traps the vapor.

What is TTD and DCA?

TTD is defined as the saturation temperature of the extraction steam minus the feedwater outlet temperature. Drain Cooler Approach (DCA) is a method used to infer feedwater heater levels based on the temperature difference between the drain cooler outlet and the feedwater inlet.

How many types of feedwater heaters are present?

There are three types of feed water heaters in use. They are: 1. Open or Direct Contact Feed Water Heaters 2. Closed Type Feed Water Heaters with Drains Cascaded Backward 3.

What are the advantages of open heater?

7. What are the advantages of open heater? Explanation: Open heaters are cheap as compared to closed heaters, in closed heaters feedwater temperature is not high.

What are the types of feedwater heaters?

Types of Feed Water Heaters (With Operation) | Rankine Cycle | Thermodynamics

• Type # 1. Open or Direct Contact Feed Water Heaters:
• Type # 2. Closed Type Feed Water Heaters with Drains Cascaded Backward:
• Closed Type Feed Water Heaters with Drains Pumped Forward:

What is the advantage of using bleed steam in regenerative Rankine Cycle?

Advantages of Regeneration cycle: Thermal efficiency is increased since the average temperature of heat addition to the cycle is increased. Due to bleeding in the turbine, erosion of turbine due to moisture is reduced.

What is a feed water heater used for in a boiler?

Feedwater Heater Operation Feedwater heaters are used to heat feedwater before the water enters the boiler. The higher the feedwater temperature, the less fuel is required to produce the steam used to produce electricity in the steam turbine.

What does preheating a feedwater heater mean?

This “preheating” means that less energy (fuel) is required to flash the water into steam. The feedwater heater, simply described, is a series of tubes carrying feedwater through a tank shell. Steam is injected into the shell and heat is transferred to the feedwater inside the tubes.

How do you measure the performance of a feedwater heater?

The primary parameters used to monitor individual heater performance are the feedwater temperature rise, the terminal temperature difference (TTD), and the drain cooler approach (DCA). Three important measurements can be taken that will provide information about the operating efficiency of a feedwater heater (Figure 4): 4.Performance measures.

How does a power plant control the level of a water heater?

Most power plants compensate for this by simply controlling the level at a point above the maximum inaccuracy of the displacer. Typically, this point is 8-in to 10-in above the drain – which greatly impacts the heater efficiency.