Commonly used waste heat boilers use smoke tubes for heat exchange, and the wall temperature of the metal heating surface and the thermal fluid discharge temperature are roughly in a multiple. Regarding the smoke pipe heat exchanger, if the wall temperature of the metal heating surface is not lower than 150, the exhaust gas temperature is usually not lower than 300, otherwise it will inevitably cause low-temperature condensation corrosion.
Thinking about the low temperature working conditions of the equipment operation, the safety factor is 15 times, the heat recovery boiler steam drum, the exhaust gas temperature of the waste heat boiler is not less than 450, and the heat of the waste heat boiler can be about 05 tons, low-temperature waste heat boiler, ** efficiency is still very low. In addition, at this time, the temperature is only the check temperature, and when the operating conditions need to be stopped and adjusted due to the operation demand, there is no way to directly stop the adjustment and control of the wall temperature.
When the temperature of the metal wall surface of the heating surface at the tail of the waste heat boiler is lower than the condensation point of sulfuric acid vapor, liquid sulfuric acid will be formed on its surface. For a long time, corrosion caused by condensation on the heating surface at the tail of each heat exchange equipment has often occurred. As a result, in the design of waste heat boilers, it is necessary to improve the exhaust gas temperature or use non-metallic materials with poor heat transfer to alleviate the occurrence of condensation and corrosion, but the problem is still not fundamentally solved. However, waste heat** equipment often corrodes after one to two years of operation until it is perforated.
Low temperature waste heatBoiler plantHere's how to do it: Fill in 1514 liters of hot water and keep the water temperature at 93. Put 2,270 litres of hot water in a container, dissolve trisodium phosphate and wetting agent, cut off the connection between the feed water and steam pipes and the external system, and separate the elements that do not need to be boiled. Then the feed water and steam system are connected to the boiler solution system. Start the solution pump and inject the boiler solution into the boiler. In order to keep the temperature of the boiler solution in the range of 138 150, steam should be supplied to the boiler solution from other steam sources, and steam can be sent from the lower part of the steam drum at regular time from the sewage pipe. Turn on the solution pump every half hour for 5 minutes to ensure that the solution is evenly distributed. After the cooking furnace is completed, the solution is discharged, rinsed with hot water, and the pH value of the water is checked at the discharge place to check whether the flushing is qualified. After inspection, if there is still oil or grease inside, steam the waste heat boiler, and repeat the furnace until there is no oil.