What is back pressure of turbine?
Another steam turbine type is a back-pressure steam turbine, which is the most suitable equipment for mechanical-drive applications, such as the drivers of compressors or pumps. The term back pressure refers to steam turbines that exhaust steam at above atmospheric pressures.
Why is it called back pressure turbine?
Back Pressure Turbine Back pressure steam turbine is also called the condensing steam turbine and reason for that is this turbine does not have condenser at its outlet and it has only one outlet.
How does a back pressure turbine work?
In a backpressure steam turbine, energy from high-pressure inlet steam is efficiently converted into electricity, and low-pressure exhaust steam is provided to a plant process. The turbine exhaust steam has a lower temperature than the superheated steam created when pressure is reduced through a PRV.
Why LP turbine is double flow?
For turbines of large output, it is normal to have several double-flow low pressure (LP) cylinders operating in parallel. The second benefit is that the double-flow cylinder effectively reduces to zero the axial thrust caused by the steam forces on the moving blading.
What is HP and LP?
HP and LP refer to ‘High-Pressure’ and ‘Low-Pressure’ shafts, and speeds. The pressures are “relative” pressures, one turbine operating at a higher pressure than the other, which is called the “low pressure” turbine (shaft).
What is the difference between impulse and reaction turbine?
The main differences between Impulse and Reaction turbines are, all hydraulic energy is converted into kinetic energy by a nozzle in the Impulse turbine and whereas In Reaction turbine Only some amount of the available energy is converted into kinetic energy.
Which type of turbine is used in gas turbine?
The spinning turbine drives a generator that converts the energy into electricity. The gas turbine can be used in combination with a steam turbine—in a combined-cycle power plant—to create power extremely efficiently. 1.
Which steam turbine has highest efficiency?
This figure is indicating that reaction turbine is more efficient than impulse turbine. The maximum efficiency of impulse steam turbine is achieved at zero degrees angle of inlet blades because this angle keeps the friction at the minimum by reducing the surface area of the blade.
Does temperature change in a turbine?
Changes in ambient temperature have an impact on fullload power and heat rate of a gas turbine, but also on part-load performance and optimum power turbine speed. The pressure ratio of the compressor at constant speed gets smaller with increasing temperature.
What is reheat turbine?
description. In turbine: Reheat and nonreheat turbines. If high-pressure, high-temperature steam is partially expanded through a turbine, the efficiency can be increased by returning the steam to the steam generator and reheating it to approximately its original temperature before feeding it back to the turbine.
What is the purpose of reheating?
The main purpose of reheating is to avoid excess moisture in steam at the end of expansion to protect the turbine. But it need not improve the cycle efficiency. That will depend (as Dmitri said) upon whether the mean temperature of reheat addition is > or < the mean temperature of heat addition before reheat.
What is the process of reheat cycle?
In a reheat cycle, the expansion takes place in two turbines. The steam expands in the high-pressure turbine to some intermediate pressure, then passes back to the boiler, where it is reheated at constant pressure to a temperature that is usually equal to the original superheat temperature.
What is the effect of reheat on the specific output?
This reduces the work of compression and increases the specific output of the plant with a decrease in the thermal efficiency. The loss in efficiency due to intercooling can be remedied by employing exhaust heat exchange as in the reheat cycle. Here heat supply and output both increases as compared to simple cycle.
What is ideal Reheat Rankine Cycle?
A steam power plant operates on the ideal reheat Rankine cycle. Steam enters the high-pressure turbine at 8 MPa and 500°C and leaves at 3 MPa. Steam is then reheated at constant pressure to 500°C before it expands to 20 kPa in the low-pressure turbine.