Heat and Mass Transfer of a Gas–Air Mixture in the Stack of an Evaporative Cooling Tower

It has been proposed that the discharge of stack gases of the waste heat recovery boiler of a gas-turbine installation into the atmosphere be carried out through the stack of a cooling tower with natural air ventilation. A technique and a PC computational program have been developed for the processes of heat and mass transfer during the motion of a gas–air mixture in the stack of a cooling tower. A calculation has been performed for the processes of heat and mass transfer occurring in a chimney-type cooling tower installed at a 200 MW CCGT (combined cycle gas turbine) unit of the Syzran′ CHP (combined heat and power plant) for two variants of its operation: without discharge or with discharge of stack gases from two heat recovery boilers into the atmosphere. The calculations have been performed for the summer period of the year. The analysis of the calculation results has shown that the proposed technical solution allows an additional reduction in the temperature of the circulating water at the outlet from the cooling tower by 1.31°C (from 28.08 to 26.77°C) and a rise in the efficiency of the combined cycle gas turbine unit up to 50.82%, i.e., by 0.08%.