Research On Low-load Operation Optimization Of A Typical 300MW Adjusted Extraction Steam Heating Unit

Under the promotion of the national energy structure reform policy,the renewable energy industry has been developing rapidly,which makes large-scale renewable energy power supply participate in the grid connection.However,due to its strong randomness and uncontrollability,it also brings great challenges to the grid peak regulation.In order to maximize the given renewable energy,forcing the heating unit to participate in the peak shaving,and peak shaving is bound to lead to the running efficiency is affected,so to heating unit can be more safe and economic operation,in the process of load for heating unit load capacity,energy consumption characteristics under different operation mode and operation optimization study is very important.In this paper,according to the design parameters provided by the heating unit manufacturer,the simulation model of the target unit is built by EBSILON power plant thermal system simulation software,and the operating parameters and energy consumption data obtained from the simulation are compared with the actual data to verify the accuracy of the simulation model.The results show that the maximum error of operating parameters of the simulation model is 0.85% under the condition of pure coagulation and heating,and the maximum error of energy consumption calculation is0.92%,which meets the requirements of the research and lays a foundation for the subsequent research and analysis.In order to study the normal safe variable load range of heating unit,it is studied and analyzed from two aspects of boiler characteristics and turbine characteristics,and according to the analysis results,the normal safe variable load range of target unit is calculated.Then,in order to study the influence of low-adding operation mode on the heating capacity and energy consumption of the unit,the hydrophobic pressure loss of unit No.7and Unit No.8 under different low-adding operation conditions was calculated and analyzed theoretically,and the variable load range of the unit under different low-adding operation modes was determined based on the calculation of variable working conditions in the simulation model.The heating capacity and energy consumption of the unit under different low-adding operation modes are calculated and analyzed.The results show that when the low-adding operation mode is all hydrophobic gravity flow,the heating capacity of the unit is the worst and the thermal economy is the highest.By adjusting the hydrophobic structure,the low hydrophobic bypass can improve the heat supply and peak load regulation capacity of the unit,but the thermal economy is reduced.Under the zero output operation mode of the low pressure cylinder corresponding to the low pressure cylinder,which is completely cut off and added to the low pressure cylinder,the peak heating capacity of the unit is optimal,and the standard coal consumption of the unit can be greatly reduced under the same heating amount.Finally to study the heating unit load change at the beginning of the pressure off at the beginning of the current condition,the optimal problem,on the basis of above research,the initial pressure optimization mathematical model is established,by building EBSILON and MATLAB data transmission interface,powerful ability of global optimization using genetic algorithms for heating unit of initial pressure under different system structure optimization,the results showed that considering the influence of heat supply and system structure change,the energy consumption of the unit is significantly reduced by the initial pressure after subsection optimization,which can effectively improve the overall thermal economy of the unit.