The waste heat recovery of flue gas can not only be used for heating or power generation to achieve energy-saving effect, but also can be beneficial to environmental protection and achieve dual effects of energy conservation and environmental protection. Guizhou Natural gas steam generator In general, the important equipment of waste heat power generation is waste heat boiler, which mainly uses heat or combustible substances in waste gas, waste liquid and other working medium as heat source, and produces steam mainly for power generation. There are many ways to recover waste heat from flue gas of waste heat boiler. Generally, comprehensive utilization of waste heat is followed by direct utilization and indirect utilization. vertical Natural gas steam generator factory Generally speaking, if heat sources are needed in the process, the waste heat utilization is mainly comprehensive utilization. First, the heat source is recovered and fed back to the process for reuse. If there is any surplus, it can be used for power generation or as the heat source for central heating; If there is no surplus, it will be directly used instead of being used for power generation; If the process does not need more heat sources, then indirect use, mainly power generation or public heating.

Effectively prevent and reduce low temperature corrosion of air preheater. Low temperature corrosion is caused by sulfur dioxide generated by combustion of sulfur in fuel. Guizhou Natural gas steam generator Under the action of catalyst, sulfur dioxide is further oxidized to sulfur trioxide. Sulfur trioxide and water vapor in the flue gas generate sulfuric acid vapor, which greatly increases the dew point of the flue gas, condenses the sulfuric acid vapor on the flue gas side of the preheater tube wall, causing sulfuric acid corrosion of the preheater. The content of sulfur trioxide has a great impact on the corrosion rate of the preheater. The content of sulfur trioxide is not only related to the sulfur content in the fuel, but also related to the oxygen content in the flue gas. vertical Natural gas steam generator factory Low oxygen combustion can significantly reduce the oxygen content in flue gas, greatly reduce the amount of sulfur dioxide oxidized to sulfur trioxide, reduce the dew point of flue gas, and effectively reduce the corrosion of preheater. Low oxygen combustion reduces the amount of flue gas. It can not only reduce the exhaust gas temperature, improve the boiler efficiency, but also reduce the power consumption of the forced draft fan and the wear of the heating surface.

When the boiler is shut down, the temperature of the heat transfer oil can be reduced to below 70 ℃ before the shutdown of the hot oil pump. In case of sudden power failure, extinguish the fire immediately, and then implement the operating procedures. Otherwise, the furnace tube will be burned out and the loss will be large. According to the type of heat transfer oil boiler, heat transfer oil shall be reasonably selected to prevent overheating. Guizhou Natural gas steam generator When purchasing unqualified heat transfer oil, do not save money or mix heat transfer oil indiscriminately. Otherwise, the consequences will be very serious. Prevent the oxidation of heat transfer oil. The strict heat transfer oil is more than 50 degrees in contact with the air, which will make the heat transfer oil crack. Its speed is amazing, and the consequences are relatively serious. After normal operation, the test crew needs to close the exhaust valve on the auxiliary exhaust pipe. After 6 months of use, the heat transfer oil must be sampled and tested according to the instructions. If problems are found, the heat transfer oil must be replaced immediately. vertical Natural gas steam generator factory However, it should be noted that different types of heat transfer oil should not be mixed. The circulation speed of the heat transfer oil should not be less than 1.5m/s. Due to the excessive temperature difference between some entrances and exits, the original design requirements were destroyed, the heat transfer oil could not maintain the original circulation state, the boundary layer became thicker, and the thermal resistance became larger, making the furnace wall exceed the oil film temperature, leading to carbon deposition, cracking, polymerization, coking, and even burning through the furnace tube.

Oil gas boilers have obvious characteristics. The main fuel is oil or gas. According to their functions, they can be divided into steam boilers and hot water boilers. Most of them are designed with large furnaces, with thermal efficiency of more than 98%. At the same time, they also have the characteristics of fully automatic and safe operation. Guizhou Natural gas steam generator Generally speaking, oil and gas boilers adopt excellent boiler body design. WNS horizontal boiler adopts wet back three return structure, which can reduce the exhaust gas temperature and make the boiler thermal efficiency reach more than 90%. Therefore, the combustion efficiency is relatively high, greatly extending its service life. vertical Natural gas steam generator factory In addition, in the design of oil and gas boiler, there are often hinged front and rear smoke boxes. The maintenance method is simple. Most of them are insulated with light aluminum silicate fiber to reduce heat loss. The external use of all stainless steel plate skin improves the appearance quality. In addition, the oil and gas boiler is equipped with an excellent combustion machine, which greatly improves its stability. The combustion machine has an automatic purging function, It can also prevent deflagration during ignition.

The existing industrial boiler flue gas waste heat recovery equipment mainly includes tubular heat exchanger and full heat pipe heat exchanger. Tube and tube heat exchanger can be composed of finned tube bundles. The advantage of finned tube is that it can withstand higher temperature, but has low heat transfer coefficient and large floor area. Guizhou Natural gas steam generator The flue gas of industrial boilers contains sulfur and other acidic substances. In the low temperature zone (flue gas outlet section), the temperature may be lower than the dew point of the acidic substances. The acidic substances will dew on the pipe wall, corrode the shell of the fin tube. The fin tube heat exchanger has poor operating reliability and low service life. vertical Natural gas steam generator factory The total heat pipe heat exchanger of boiler flue gas waste heat recovery equipment is composed of heat pipe bundles. Its shell is made of multi-layer composite materials. The heat pipe structure is complex, the cost is relatively expensive, the service life is short, and the steel consumption is large. It is difficult for users to accept it, and it is difficult to promote its application in production. The composite heat pipe heater not only takes into account the heat exchange effect, but also takes into account the economic affordability of the investors in production, which is particularly suitable for the current situation in China's industrial production.