300 MW Thermal Power Unit Boiler Non-electric Pump Water Supply Optimization
5+2:B 1 Overview Unit 7, unit capacity 300 MW; Harbin boiler plant model HG-10 to 18.2-YM8, designed evaporative capacity 910t/h boiler, model manufactured by Harbin Steam Turbine Analysis Plant N3(1)-16.7/537/537, with 8 sections of non-adjustable extraction turbine; 2X50% capacity steam-powered water pump group and 1X50% capacity electric water-feed pump group are equipped in the system, and each unit is equipped with an independent auxiliary steam system. Auxiliary steam is connected with the parent pipe. The auxiliary steam source can be provided by two aspects: adjacent engine auxiliary steam header; the second stage extraction steam (cold reheat) auxiliary steam system is mainly used to satisfy the unit start, stop and abnormal fuel atomization, turbine shaft seal, Deaerator heating and other steam needs. 2 Traditional water problems and existing problems Small steam turbines have two independent high and low pressure steam sources. The low pressure steam source is the main engine four-phase extraction or the high-pressure auxiliary steam is connected to the steam, and the high-pressure steam source is the new steam. The small turbine exhausts steam to the condenser. The design principle of the unit water supply system is to use the electric feed pump group as the working pump when turning on and off the unit. After the unit load exceeds 90 MW, one or two sets of steam-driven water pump groups will be put into operation as the load increases, and the load exceeds 150 MW to exit the electricity. The pump set is a standby pump for normal operation. Traditionally, the water system has the following problems: When the unit is started cold, it takes 15h or more to start the electric pump to the unit with a 150MW load (that is, when the electric pump is stopped). During this time, the electric feed pump consumes a large amount of factory power. When the steam pump starts, warming the warm pump takes a while. Therefore, before the unit load 150MW, if the electric pump fails, the steam pump can not be immediately put into operation, it will inevitably cause the boiler feedwater to be interrupted, thus making the whole unit start working failure. Reduce the reliability of the equipment. Therefore, how to make the boiler feed pump operation more safe, economical and reasonable is a problem that must be considered. When the unit is started, the use of electric pumps without water is a feasible optimization solution. 3 Optimization Scheme and Feasibility Analysis for Sheung Shui Mode 3.1 Optimization Scheme for Sheung Shui Mode The following three optimization schemes for Sheung Shui are proposed: When the cold state (or warm state) of the unit is no longer started, the electric water supply pump is no longer started, but the deaerator is used first. The pressurization method (pre-pump for starting the steam pump in warm state) feeds water into the boiler instead of the electric feed pump to the boiler. When the drum pressure, static pressure on the water is difficult, you can start the steam pump pre-pump to increase the hydraulic head. This program can be called static pressure water. Due to the low lift of the pre-boost pump of the steam pump (outlet pressure 1.34 MPa), when the drum pressure reaches approximately 0. 5 MPa, the pre-boost pump cannot further satisfy the boiler feed water pressure requirement. At this time, the electric feed pump is still not activated, but the steam main feed pump is directly activated (in this case, the steam turbine of the small steamer is the high pressure auxiliary steam header to steam), and the opportunity of using the steam turbine to raise the speed of the steam turbine is further increased to improve the water supply. Pressure to meet boiler water supply needs. When the load is increased to 120MW, the steam source of the small turbine is switched, that is, the steam is switched from the high-pressure auxiliary steam connecting box to the fourth-stage extraction steam until the full load. When the unit's hot (or extremely hot) state starts, it directly uses the high-assisted steam source impulse small turbine to start the steam main feedwater pump. 2 Feasibility analysis of feasibility analysis of feasibility of deaerator pressurization to boiler water Yang Minyuan. Thermal Power Plant Power Device M Bu Beijing: China Water Power Press, 1996 2 Zheng Tien Kuan. Thermal Power Plant Mb Beijing: China Electric Power Press, 1997 Valve Parts,Metal Valve Parts,Valve Body Parts,Butterfly Valve Parts SUZHOU YUEDA VALVE CO., LTD. , https://www.szyuedavalve.com