Sludge (sludge) drying

Sludge (oil sludge) drying high temperature pyrolysis classification treatment system

Process flow description
The basic principle of pyrolysis technology Sludge pyrolysis is to use the thermal instability of the organic matter in the sludge to heat it under anaerobic conditions to thermally crack the organic matter. The organic matter is cracked according to its hydrocarbon ratio, forming a higher utilization value. The gas phase (pyrolysis gas) and solid phase (solid residue) of the sludge are easy to store, transport and use. way. According to the operating temperature of the pyrolysis process, it can be divided into low temperature, medium and high temperature pyrolysis, low temperature pyrolysis is within 500 °C, medium temperature pyrolysis is between 500 °C and 800 °C, and high temperature pyrolysis is above 800 °C. Factors affecting the pyrolysis process and product yield and composition include pyrolysis temperature, pressure, heating rate, gas-solid phase residence time and material size, among which pyrolysis temperature is the main influencing factor.
Sludge pyrolysis process description A complete sludge pyrolysis process includes storage and conveying system, drying system, pyrolysis system, combustion system, energy recovery system and exhaust gas purification system. The storage and transportation of sludge is the beginning of the whole process, which plays the role of storing and transporting sludge into the drying device. The moisture content of dewatered sludge in sewage treatment plants is generally around 80% and cannot be directly pyrolyzed. The moisture in the sludge is removed through the drying system to reduce the moisture content of the sludge to 20% to 25%. Pyrolysis is the cracking of solid sludge in an oxygen-free environment to generate gaseous and solid products. The gaseous product is pyrolysis gas, which is a combustible gas. The pyrolysis gas generated from the pyrolysis equipment (pyrolysis drum) contains certain harmful substances and can be burnt, which can utilize energy and at the same time convert the harmful substances into fully oxidized flue gas. The pyrolysis gas can also be treated with flue gas to remove harmful substances, and the clean pyrolysis gas can be supplied to the engine or gas turbine. The oxygen-free environment of the system reduces or prevents the formation of PAHs. The solid product is the residue after the pyrolysis of the sludge, and its structure is easy to wet, so the slag discharge device needs to be equipped with anti-clogging measures. In addition, the chemical properties of the pyrolysis residue are stable and resistant to strong acid corrosion, and the heavy metals in the sludge are solidified and difficult to precipitate again. The pyrolysis gas generated by pyrolysis passes through the cyclone dust collector and enters the combustion chamber together with the waste gas from the sludge storage bin for combustion, which can prevent the leakage of peculiar smells. The flue gas generated by the combustion chamber is preferentially used for the heating of the pyrolysis drum. The temperature of the flue gas at the outlet of the pyrolysis drum is 600°C, and this part of the flue gas enters the waste heat boiler for waste heat utilization. When the system's own energy cannot maintain its own balance, the combustion chamber needs to be supplemented with additional fuel (natural gas or oil) to maintain the system's energy balance.