Design And Applications Of Heat Pipe Air Preheaters

Heat pipe is a kind of heat transfer components developed in1960s. It has a very high thermal conductivity, which is102to104times larger than metal (Ag, Cu, Al). On the basis of the studying to heat pipe heat transfer mechanism, the heat pipe air preheater is produced through designing and calculatin to which such as heat resistance, temperature, heat pipe air preheater in the process of heat transfer. The reliability and feasibility of the structure is verified by the actual use of performance in the process of flue gas recoverying.Using219heat pipes, with φp32×3, length1.18m of heating section,0.8m of the condenser section length,0.02m of adiabatic section length, the total heat317525.7kcal/h of the flue gas heat can be recoveried. The recovered heat is used to heating the combustion air so that its temperature can be increased to119℃from25℃; The heat transfer coefficient of heating section with a fins is414.5w/(m2℃). Same as386.0w/(m3℃)in heating section of heat pipe. The average heat load of the single heat pipe is1.69kw which is far less than the maximum allowed in a single heat transfer; The wall temperature of side of designed heat pipe air preheater flue gas is120.6℃which is higher than the dew point of water, it will not appear water dew point corrosion; And the voltage requirements wall thickness is1.05mm which is calculated according to the intensity on the withstand, it is far less than the actual wall thickness of3mm, so the design is meet to the requirements.For waste heat recovery to Shanghai Petrochemical Chen Shan pier10T/h steam fuel boiler, through the actual operating, the results of air heat pipe air preheater performance show that the design and production of heat pipe air preheater device is fully able to meet to needs of gas heat recovery.Therefore, the use of heat pipe air preheater as flue gas heat exchanger for heating the cold air combustion shows that the design is feasible. Improving boiler combustion performance can be achieved to reduce fuel consumption and save energy.