Sludge pyrolysis technology

Sludge pyrolysis refers to a treatment method that decomposes sludge under an inert atmosphere and at a certain temperature. Because the pyrolysis process isolates oxygen and operates at a relatively low temperature, it significantly reduces the generation of secondary pollutants such as nitrogen oxides and sulfur oxides. Furthermore, the products of sludge pyrolysis—pyrolysis char residue, pyrolysis tar, and pyrolysis gas—can all be recycled. Pyrolysis tar and pyrolysis gas have a certain degree of combustibility, allowing for the recovery of some energy. Pyrolysis char residue is porous and suitable as an adsorbent and catalyst. Therefore, pyrolysis is one of the more appropriate disposal methods for municipal sludge. This paper will describe the research and development of several common municipal sludge pyrolysis technologies, the characteristics of pyrolysis products and their influencing factors, and the applications of pyrolysis products. It will also analyze unresolved issues and development trends in municipal sludge pyrolysis to promote further development of sludge pyrolysis technology. This method is applicable to municipal sludge, industrial sludge, oily sludge, and other materials.

After low-temperature drying, the sludge enters a rotary pyrolysis furnace for pyrolysis. The pyrolysis furnace is jacketed, and high-temperature flue gas heats the material through the jacket. The sludge undergoes pyrolysis in an anaerobic environment in the pyrolysis chamber, producing peat and combustible gas. The pyrolyzed peat is cooled by a water jacket and then transported to the sludge peat temporary storage bin via a conveyor. The combustible gas is drawn into the hot air furnace by negative pressure through a pipeline and burned. The combustion produces high-temperature flue gas with a temperature of 950~1050℃, which is held for more than 2 seconds to control the formation of dioxins.