Cycle of | Basic | Feed | Water | Heater

The main function of the Feed Water Heater is increasing efficiency in power plant steam cycle. Extraction steam from the turbine used to heat the feed water so that the Final Feed Water Temperature had passed (from point A to M). Feed Water Heater is basically a heat exchanger (heat exchanger). Power plant has 7 units of Feed Water Heater is 3 units of Low Pressure Heater (LPH 1, 2 and 3), 3 units of High Pressure Heater (HPH 5, 6 and 7) and the Open Feed Water Heater is Daerator. For LPH and HPH 5,6,7 1,2,3 is Close Feed Water Heater with shell and tube type heat exchanger.

Heat transfer occurs between the feed water temperature in the tube with extraction steam from the steam turbine and the drain of the Feed Water Heater on the top shell. Condensate Pump Condensate water is pumped by the deaerator through LPH 1, 2 and 3 respectively. Then the feed water is pumped by a Boiler Feed Pump (BFP) to the economizer to advance through the timber 5, 6 and 7. Another function of the heater is to improve the steam quality, which capture some steam at the turbine blade will reduce the wetness of steam, thereby reducing the effect of condensation heat transfer processes Most of the heater on the condensing section occurs. Although superheating made very high temperature, the heat transfer in desuperheating section remains small. Drain the cooling is the smallest part of the process of heat transfer in the heater.

Due to certain reasons such as tube leakage or leakage valve, feed water heater can be out of service (cut heater operation). In Design Manual Book (Hamen-Subelco Vol OI), the operation of the heater cut operation can be done with certain limitations. There are several parameters that must be observed particularly fibrasi problem and the maximum weight allowed when there are concessions in the out of service. However, the operation of the heater cut in a long time is not recommended because it will reduce the life time of the other heater. Turbine has been designed to anticipate the heater cut operation without overstressing the following conditions:
A. A condition
One or more non-contiguous heater (nonadjacent - one chasing turbine) can be out of service from the system.
Example: Heater 7, 5, 3 out of service. Load 100%
2. The condition B
If there is a heater that successive (adjacent) in the out of service then the load can still be maintained as long as there is above all the heater come on out of service.
Example: Heater 7, 6, 5 out of service. Load 100%
3. The condition C
Turbine heater can be operated with the highest in service and a combination heater out of service sequentially below. Load must be reduced 10% when there are 2 consecutive heater out of service, reduced 20% when there are three successive heater out of service. Reduction of the maximum allowable load is 50% of the nameplate. Loading beyond these limits is the responsibility of the owner.
Example: Heater 6, 5 out of service. Load 90%
Heater 6, 5, 3, 2 out of service. Load 90%
Heater 6, 5, 3, 2, 1 out of service. Load 80%

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