Study On Calculation And Control Of Condenser Optimal Pressure Of 600MW Air Cooling Unit

Air-cooling unit which keeps its biggest advantage in water-saving performance,compared to the wet cooling unit,has great prospection water-short and coal-rich area.Moreover,the technology of direct air cooling is widely used,due to its significant effect on water-saving in air cooling unit.This paper focuses on the analysis of 600 MW direct air cooling unit.By using the ε-NTU method to establish the mathematical model under variable conditions for direct air cooled condenser,the influences of the temperature of the air entering the condenser,the exhaust flow,the frontal velocity of air,the internal and external fouling resistance of the pipes on pressure of the condenser are studied,and a performance curve of the condenser in variable conditions is drawn,based on which sever detailed information has been obtained.Based on the traditional definition of the optimal condenser pressure of direct air cooling unit as the start point,a slightly increasing load of the turbine is calculated in different loads and different condenser pressures,by using the equivalent heat drop method and Frugal formula.Besides,the relation between condenser pressure and fan power consumption has been proposed with the help of the fan theory.Thus an optimal condenser pressure curve has been obtained.Finally,the condenser pressure is controlled by the auto disturbance rejection controller and PID controller based on the calculated value,and better results have been got based on the particle swarm optimization.The results of this research play a guiding role in the economic operation of the unit,advising the unit work under the condition of optimal condenser pressure,for the purpose of saving energy.