Let incoming steam temp is 270c and its saturation temp is 180c at that pressure. Incoming water temp is 120 And after heating in hp heater temp increases to 185c. Then ttd 180-185= – 5c. In high pressure heater water is at high pressure so its latent heat is low. So it gets superheated making ttd negative.
What is TTD of condenser?
While TR is an indication of the amount of heat absorbed by the circulating water, TTD is a measure of the efficiency with which heat is transferred from the shell side of the tube to the water side. A lower TTD is always better, and all condensers are designed with a specific design TTD.
What do feedwater heaters do?
A feedwater heater is used in a conventional power plant to preheat boiler feed water. The source of heat is steam bled from the turbines, and the objective is to improve the thermodynamic efficiency of the cycle.
What is drain cooler approach?
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. … An increasing DCA temperature difference indicates the level is decreasing and a decreasing DCA temperature indicates a rise in level.What is turbine in thermal power plant?
A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. … A steam turbine connected to an electric generator is called a turbo generator.
What is vacuum efficiency?
It is defined as the ratio of actual vacuum in condenser as recorded by the vacuum gauge to the ideal vacuum. In that case total pressure in condenser will approach ideal pressure. … Vacuum efficiency is also defined as the ratio of the partial pressure of steam to the measured condenser pressure.
Why vacuum is needed in condenser?
The removal of air and other noncondensable gases from the condenser shell side is required for proper heat transfer from steam to cooling water in the condenser and, thus, to maintain high vacuum in the condenser.
How do you convert heat to efficiency?
To express the efficiency of a generator or power plant as a percentage, divide the equivalent Btu content of a kWh of electricity (3,412 Btu) by the heat rate. For example, if the heat rate is 10,500 Btu, the efficiency is 33%. If the heat rate is 7,500 Btu, the efficiency is 45%.How do you calculate condenser efficiency?
Vacuum efficiency = (Actual vacuum in condenser X 100)/Max. Obtainable vacuum. Example-4: The air leakage into the steam condenser is 0.721 kg/min.
How is heat rate calculated?Using the well-known definition of efficiency and heat rate— h = P/HC and HR = 3,412/h Btu/kWh—it can be shown that the value of 1 Btu/kWh reduction in heat rate is given by Equation 2.
Article first time published onWhat is closed feedwater heater?
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 are the types of feedwater heaters?
- 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 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.
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.
Why is steam used to rotate the turbine?
When steam blows into the turbine, the spinning blades (fitted inside the outer container) are flown at higher rates. Because of high pressure, the continuous flow of electricity is generated at incredibly high speed, therefore the rotating speed increases when comparing with other wind and water turbines.
How does steam power a turbine?
In simple terms, a steam turbine works by using a heat source (gas, coal, nuclear, solar) to heat water to extremely high temperatures until it is converted into steam. … The potential energy of the steam is thus turned into kinetic energy in the rotating turbine’s blades.
How many types of turbine are there?
1 Turbine. A turbine is a work producing device. Production of power is achieved by expanding a fluid. Mainly, there are two different types of turbines, steam and gas turbines.
What is barometric leg?
A barometric leg is basically a condensate drain. In a vacuum system that is used to condense steam and condensable vapors through heat exchangers or condensers, the condensate is normally dropped into a receiver tank that is often vented to atmosphere or a low-pressure vent system.
What is pressure in condenser?
Condensing pressure: The pressure at which the refrigerant is phase changing from a vapor to a liquid. Evaporating pressure: The pressure at which the refrigerant is phase changing from a liquid to a vapor.
What is back pressure in condenser?
High Condenser Pressure High condenser back pressure is the most obvious plant measurable that results in lost revenue or excess operating costs. Turbine exhaust back pressure is directly related to lost power output to the generator that converts mechanical energy to electrical power.
Why condenser is used in power plant?
In thermal power plants, the purpose of a surface condenser is to condense the exhaust steam from a steam turbine to obtain maximum efficiency, and also to convert the turbine exhaust steam into pure water (referred to as steam condensate) so that it may be reused in the steam generator or boiler as boiler feed water.
What is boiler efficiency?
Definition of Boiler Efficiency is “The percentage of the total absorption heating value of outlet. steam in the total supply heating value.” In other word, it is a rate how the boiler runs efficiently.
Which is the jet type condenser?
Jet condenser is a mixing type condenser where exhaust steam is condensed mix up with cooling water.In a jet condenser, high power is required for condensation.
What is the pressure of steam in condenser?
Typically the cooling water causes the steam to condense at a temperature of about 25 °C (77 °F) and that creates an absolute pressure in the condenser of about 2–7 kPa (0.59–2.07 inHg), i.e. around −95 kPa (−28 inHg) below atmospheric pressure.
Which condenser is suitable for high capacity plant?
SI.no.Jet Condenser1.Cooling water and steam mixed up2.It is less suitable for high capacity plants3.Condensation is wasted4.It requires less quantity of circulating water
What is relation between cooling water temperature and condenser pressure?
Condenser pressure is affected by the cooling water temperature and mass flow rate. The smaller the cooling water flow rate for a given cooling water inlet temperature, the higher will be the condenser pressure.
Is a lower heat rate better?
Heat rate is a term commonly used in power stations to indicate the power plant efficiency. The heat rate is the inverse of the efficiency: a lower heat rate is better.
What is net heat rate?
Net Heat Rate means the Net Electrical Output divided by the total fuel consumed to produce the Net Electrical Output, expressed in MMBtu per MWh.
What is the difference between heat flux and heat rate?
Heat flux or thermal flux is the rate of heat energy transfer through a given surface, per unit surface. … Heat rate is a scalar quantity, while heat flux is a vectorial quantity. To define the heat flux at a certain point in space, one takes the limiting case where the size of the surface becomes infinitesimally small.
What is thermodynamic heat rate?
The heat rate is defined as the total amount of energy required to produce one kilowatt-hour (kWh) of electricity by an electric generator or power plant. It is the input rate required for generating unit power. The heat rate can also be described as the ratio of thermal inputs to electrical output.
What is steam and heat rate?
Steam rate = kg/kWh. … Heat rate: It is rate of heat input (Q1) required for producing unit work output (1 kW).
