Cold End System Optimization And Energy Conservation Of Direct Air-cooled High Back Pressure Heat Supply Power Units

Heat and electricity are the two important forms of energy supply to the daily life of residents and the modernization of social development.Because the extraction steam parameters are still pretty high,there is still large energy loss for the traditional middle extraction steam heating unit.By contrast,the exhaust steam of direct air-cooled high pressure heat supply power unit is used as heat source,which better meets the “temperature counterparts,cascade utilization” energy system principle.It vigorously develops in recent years.Compared with traditional middle extraction steam heating unit,the cold end of direct air-cooled high pressure heat supply power unit has its own operation complexity significantly.When the external thermal load and electrical load changes,the corresponding parameters of operating unit,limiting boundary and energy consumption characteristics are different from the condensing unit or back pressure type unit.For the air-cooled heating unit,the characteristics of heating system has a strong dependent change with environment temperature.On the one hand,environmental temperature change influences the demand of heat load,on the other hand,the cooling effect of the air-cooled island is influenced by the environmental wind temperature,wind speed and other factors.As the two parts of the unit cold-end,the heating condenser which used as the heat source and the air-cooled island which undertakes the remaining cooling load have complex coupling relationship between each other.Considering the importance of heating in the winter,most units t ake the operation mode determined by “pricing electricity based on heat amount ”principle.The air-cooled island operation in winter should follows the blocking pressure and minimum freezing flow strict requirements strictly,therefore,the cascade heating characteristics of direct air-cooled high pressure heat supply power unit and coordinated operation optimization of critical air cooling system and heating system under different conditions are extremly important.Considering the heat supply demand and cold-end performance,EES(Engineering Equation Solver)and Ebsilon platform were introduced to model the heat transfer characteristics of heating system and air-cooled island for illustrating the heating system in winter.The flexible operation boundary was discussed in quality-volume regulation due to heating load and power load.The optimized operation mode of both heating system and air-cooled system were determined,taking great reference for the collaborative operation optimization of such system.Using a provincial power grid electricity load,wind load and thermal load in the northwest region as an example,the elastic operation capability of direct air-cooled high pressure heat supply power unit in typical temperature range is investigatd.The smoothing effect of thermal unit elastic operation for the wind power fluctuation was explored,which provided a reference for the Internet energy supply side reform and regional energy planning.