Thermal Performance Analysis Of Low Pressure Steam Heating And Low Vacuum Heating System

Facing the energy crisis and environmental crisis,people pay more attention to cogeneration.Combined with the thermal performance index and actual operation status of thermal power units in Anshan Iron and steel Co.,in order to effectively utilize the existing thermal energy resources,to realize the cogeneration mode of different generating units in Angang plant,and to improve the current situation of coal-fired heating in the original steam boiler in Anshan,The results are as follows.Through the calculation of thermal performance such as working medium balance and energy balance,the indexes of condensing steam turbine generator in cogeneration are determined,and the thermal economic index is analyzed.The thermal performance of 350 MW condensing steam turbine unit before and after low vacuum heating transformation is analyzed and compared in detail.When low vacuum circulating water is not used for heating,a large amount of heat is lost to the atmosphere through the cooling tower,which can not be reused and wasted.However,under the low vacuum heating condition,the low vacuum circulating water heating mode absorbs the residual heat of exhaust steam,reduces the cold source loss to zero,and significantly increases the thermal efficiency of the thermal power plant.However,due to the high exhaust pressure and temperature rise,the thermal efficiency of steam turbine is relatively reduced.The total thermal efficiency of the power plant has been greatly improved,so it has great advantages.Under the premise of ensuring the safe and stable operation of the steam turbine,increasing the back pressure of the unit and reducing the vacuum degree of the condenser will increase revenue.It is concluded that with the increase of heat extraction steam,the exhaust steam of the steam turbine is increased and the exhaust steam entering the condenser is reduced.The reduction of the exhaust steam into the condenser increases the vacuum degree of the condenser and reduces the temperature,pressure and enthalpy of the exhaust steam of the unit.In this way,the cold source loss of the unit is reduced,the heat utilization rate of the unit is improved,and the thermal efficiency and steam consumption of the steam turbine are significantly reduced,and the power generation efficiency of the unit is improved.In addition,although low vacuum heating and low-pressure steam extraction heating are relatively mature and common heating technologies in China,these technologies can improve more reliable heat sources for users,but there are still different differences.Through the analysis of the heating transformation of the condensing steam turbine generator unit,it can be concluded that although the thermal efficiency of the low vacuum heating steam turbine generator unit is slightly reduced,the overall thermal efficiency of the power plant is greatly improved,which has obvious advantages compared with the low-pressure steam extraction heating steam turbine generator unit.