Study On "Synergistic Regulation" Of Boiler Water Supply System Under Variable Load In Power Plant

In order to meet the requirements of variable load, most of the generating setsemploy composite operation mode as level pressure-sliding pressure-level pressure,and deploy the boiler feed-water system which adopts multiple pumps joint operation.The electricity consumption of the feed-water pumps is the maximum amongauxiliary equipments in power plants, the plants’ economy is directly impacted byenergy consumption of feed-water pumps, thus the problem on adjustment of boilerfeed-water pumps have become crucial. Based on the energy-saving features ofvariable speed regulation, the scheme that boiler feed-water pump variable-speedcontrol and throttling adjustment in combination is put forward in this thesis.This thesis adopts the method of resolution to introduce fitting method ofcharacteristic equation when boiler feed pump employs different adjustment modesunder the sliding pressure operation, and which the calculation method of the pumpshaft power. In meeting the conditions of variable flow, this thesis selects feed-watersystems of200MW with series connection, overlap mode,300MW and600MW withoverlap mode when generator units are sliding pressure operation as examples,According to the principle of least square method, the curve equations of feed-waterpump and booster pump are fitted by Orgin, regardless of the boiler feed-water pumpusing simple variable speed regulation or synergistic regulation, the thesis calculateshereby shaft power of water supply system, and compares their energy saving feature,in addition, this thesis analyses the change of the water supply pipeline characteristics.Directing at the calculation results, the relation curves of the pump head, efficiency,speed ratio, shaft power and drag coefficient changing with the load are drew, thisthesis analyses and determines the best way to adjustment of the feed-water pumpunder different loads in hybrid sliding-pressure operation of units, and points outsafety regulation mode of operation, which provides a theoretical basis to ensure thatthe scheme is effectively applied in the project．...