Dry-wet Combined Cooling System

- Jul 15, 2017-

               At present, there are three kinds of air cooling systems used in power plants, namely, direct air cooling system, indirect air cooling system with surface condenser and indirect air cooling system with ejector (hybrid) condenser.Cooling System

              Direct air-cooled system, also known as air cooling system. Direct air cooling refers to the steam turbine exhaust air to condense directly between the air and steam heat exchange. The required cooling air is usually supplied by means of mechanical ventilation. Direct air-cooled condensate equipment called the air condenser, the advantages of the air cooling system is less equipment, simple system, investment in infrastructure, small footprint, air volume adjustment flexibility. The system is usually matched with a high back pressure turbine. The disadvantage of this system is that the operation of large exhaust pipe sealing difficulties, to maintain the vacuum in the exhaust pipe, the start-up time for the vacuum is longer, the unit efficiency is low, one energy consumption.Cooling System

            The Heller indirect air cooling system is composed of a jet condenser and an air-cooled tower equipped with a FU-Gothic radiator. The cooling water in the system is a high purity neutral water (ph=6.8-7.2). The neutral cooling water enters the condenser and condenses directly with the steam turbine exhaust steam. Most of the cooling water from the cooling water circulating pump to the air cooling tower radiator, after cooling and air convection heat transfer through the pressure-regulating turbine to send the cooling water to the jet condenser into the next cycle. The few parts of the heated circulating cooling water are treated by the condensate finishing unit and sent to the steam turbine regenerative system. The advantage of Heller Indirect air cooling system is to operate in low pressure water system with micro-positive pressure. Its average annual back is lower than the direct air cooling unit, slightly lower than Harmon type indirect air-cooled unit, so the unit coal consumption is low. The disadvantage is the equipment is many, the system is complex, the cooling water circulation pump pit is deep.Cooling System