An open feedwater heater is basically
a mixing chamber, where the steam extracted from the turbine mixes with the water exiting the pump
. In an ideal condition, the water leaves the heater as a saturated liquid at the heater pressure.
How do feedwater heaters increase efficiency?
By increasing the feed water temperature
, the feed water heater increases the overall efficiency of the steam power plant. Feed water heater increases the feed water temperature near to the boiling point. So, the interning water of the boiler can easily transfer into steam and improve the efficiency of the plant.
What are the various advantages of using multiple feedwater heaters?
Reduce fuel required for combustion by increasing the initial water temperature to the boiler
; Reduce heat losses in the condenser; Minimize thermal transients within the boiler; Lower emissions as fuel use is reduced due to improved heat rate.
What is the purpose of a feed water heater?
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.
Is pressure constant through a closed feedwater heater?
For closed feedwater heaters, heat is transferred from the extracted steam to the feedwater without any mixing taking place. Since they do not mix, the two streams can be at different pressure. …
The enthaply of steam remains constant during
this throttling process.
Which of these is a disadvantage of open heater?
Which of these is a disadvantage of open heater? Explanation: The disadvantage is
the necessity of a pump at each heater to handle the large feedwater stream
.
Why at least one open heater is used?
Why at least one open heater is used? Explanation:
The open heater works as a deaerator
.
Which of the following is true for an open feedwater heater?
Which of the following is true for an open heater? Explanation: The open
heater has high heat transfer capacity
.
Which device utilizes the heat of steam for heating feed water?
Superheater
: A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming.
What is the efficiency of Rankine Cycle?
In modern nuclear power plants, which operate the Rankine cycle, the overall thermal efficiency is
about one-third (33%)
, so 3000 MWth of thermal power from the fission reaction is needed to generate 1000 MWe of electrical power.
What is the difference between the open and closed feedwater heater?
An
open heat exchanger
is one in which extracted steam is allowed to mix with the feedwater. … Closed feedwater heaters are typically shell and tube heat exchangers where the feedwater passes throughout the tubes and is heated by turbine extraction steam.
Why do we use 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 chemical is fed to the deaerator?
Chemical Deaeration
Equipment manufacturers state that a properly operated deaerating heater can mechanically reduce the dissolved oxygen concentrations in the feed water to 0.005 cc per liter (7 ppb) and 0 free
carbon dioxide
. Typically, plant oxygen levels vary from 3 to 50 ppb.
What is low pressure heater?
Low pressure heaters are
designed for regenerative heating of district water in the regeneration systems
of the steam turbines by cooling and condensing steam, picked up from intermediate stages of the turbine units.
What is the difference between the Brayton cycle and the Rankine Cycle?
Rankine cycle is a steam engine, the water is boiled, evaporated, used for work and then condensed for re-use, thus making it a closed cycle. …
The working fluid undergoes a phase change in
the Rankine cycle whereas in Brayton cycle there is no phase change the working fluid always remains in the gaseous phase.
What is regenerative Rankine Cycle?
The Ideal Regenerative Rankine Cycle
The regeneration process in steam power plants is accomplished by extracting
(or bleeding) steam from turbine at various stages
and feed that steam in heat exchanger where the feedwater is heated. These heat exchangers are called regenerator or feedwater heater (FWH).
