The chemical industry and paper industry produce a large amount of industrial wastewater in production. The toxic wastewater is incinerated by the waste liquid incineration waste heat boiler, so that the wastewater is decomposed into non-toxic gas during the combustion process and discharged into the atmosphere. Because the wastewater contains a lot of water and has poor flammability, fuel must be consumed during the combustion process to keep the furnace temperature around 850°C so that the wastewater can be effectively decomposed.