A New Type Heat Exchanger for Coal Burning Boilers

To make the best of heat energy in the flue gas exhausted from a coal burning boiler, the design proposal for a new type of heat exchanger was put forward in the paper. Via the new type of heat exchanger, temperature of the flue gas can be decreased from 130~140°C to 70~80°C for the boilers in a coal burning power plant, from 140~160°C to 50~60°C for the steam boilers in a heating station of enterprises or factories. Making use of the new type of heat exchanger can increase the heat efficiency of coal burning power plants by about 3%, and can increase the heat efficiency of the heating station of an enterprise or a factory by about 6.7%, more than 0.5~1.0% with glass tube economizer or heat pipe preheater. The wet ash deposited on the heating surface of the heat exchanger can be cleaned away at any time by a kind of special mechanical ash-cleaner. Main parts of the heat exchanger are made of acid proof stainless steel to avoid acid corrosion on metal. The cost-effectiveness analysis indicates that payback period of the loan to equip boilers with the new type of heat exchanger for energy-saving improvement may be less than 1.8-year for a coal burning power plant, less than 0.7-year for the heating station of an enterprise or a factory.