Renewable energy solutions for the saving energy industry - Energy - Solar Power
Frequency inverter reconstruction of Power Plant promoted heightening of economy benefit. Frequency inverter won acceptance of user as its high reliability, flexible adjustment and simple operation. A Power Plant was set up in June, 2000. Its predecessor was one of key plants of state. The plant put into service in 1957. Now it has 4×50MW, 2×142MW, total ten boilers and six generators. Total capacity is 484MW. The plant supplies power to big enterprise near to it.
Application/Industries Served
In the power plant, for main equipments, such as FD fan, ID fan, feed pump and circulating pump, output power cannot change with load variety. Damper control or valve control causes much energy waste. Therefore, energy saving and emission reduction are brought up on the agenda. Power plant is in search of way of energy saving in term of technology.
Making technology reconstruction for main equipment by medium voltage variable frequency technology is an effective method of energy saving.
Problems of recycle water system
During reconstruction of ventilation cooling tower of circulating water system in 2001, power plant reduced circulating water flow to 5000t/h from 10000t/h, which lowered cost of power generating, and gained evident economy benefit. But there was a problem. Four sets of axis flow recycle pump (rated output 9720m3/h) were equipped for inlet of tower specially. Output of pump was too big, which could not match with water tower.
As is well known, performance curve of axis pump is very steep. Pipe resistance variety affects little on flow variety. Outlet gate of the pump and inlet gate of well can not be throttled, which leads to difficult adjustment of flow. Thus flow adjustment only depends on adjusting condenser outlet gate, starting/stopping circulating pump and increasing/decreasing primary water flow. That is not convenient at all. Furthermore, it is wasteful. For example, in winter, temperatures of circulating water inlet and outlet are low. If a recycle pump runs in rated condition, in order to ensure pump inlet normal, output gates of all machines open big. In the meantime, in order to maintain main pipe pressure, circulating pump needs to starts, which increases power consumption. In summer, because of high temperature of coming water, primary water flow increases to ensure temperature of air discharge not too high. Condenser opening is also big, causing #3, 4 water level flooding. Starting recycle pump would oblige condenser outlet gate big opening. All eight circulating pumps starting can not ensure #3, 4 water level. Furthermore, starting circulating pump and increasing primary flow lead to cost rising.
Install frequency inverter on #1, 3 recycle pump according to actual state and strategy of sustainable develoment.