Continuous Pyrolysis Technology for Oily Sludge Treatment in the Chain-Slap Conveyors

Abstract

In the process of petroleum exploitation, the annual production of oily sludge in China’s petroleum exploitation industry alone has exceeded one million tons, which causes great harm to the environment. In order to face this problem, a variety of treatment methods have been sprung out, but the most of them are polluting the local soil and groundwater eco-environment. Pyrolysis technology for sludge treatment has several advantages, which have already made it a mainstream approach attracting worldwide attention. In this work, oily sludge from Yanshan Petrochemical Company was processed at the newly developed industrial-scale reactor. The sludge transportation in the whole system was achieved by the use of chain plate conveying, which has the advantages of preventing coking, effective sealing of sludge inlet and outlet, etc. First, lab-scale experiments were carried out at temperatures between 450 °C and 600 °C to obtain the best reaction conditions in the industrial-scale equipment. It was found that the maximum pyrolysis oil yield of 17.1 wt.% was obtained at 500 °C. The properties of oily sludge and related compositional characterization of the products (permanent gas, pyrolysis oil, and pyrolysis char) after the treatment were comprehensively analyzed. The study showed that the oily sludge in the reactor was completely converted, and resource utilization of the feedstock could be realized.