Pyrolysis of Oil Refinery Sludge: A Thermo Kinetic Study

Abstract

Petroleum refineries are producing an enormous amount of oil sludge and declared as “Hazardous Waste” under schedule waste 2. This sludge is a mixture of oxyhydrocarbon, traces of heavy elements, oil and water. If this oily sludge dispose of in an environment prior to treatment, then it will cause a great threat to both marine and land environment. Therefore, research is being underway to find the most optimized process of its treatment and disposal into environment. Combustion, gasification, anaerobic digestion, pyrolysis and few other methods are most commonly employing and currently under research for oily sludge disposal. In above mention process pyrolysis is considered to be the most suitable candidate. The current research emphasis on the pyrolysis process of oily sludge to study the thermal degradation behavior through thermo gravimetric analysis and by using lab scale reactor (autoclave pyrolysis unit) to obtain useful products. Elemental composition of oily Sludge is determined by ultimate and proximate analysis. The Effect of heating rate (5°C/min, 20°C/min and 40°C/min) on thermal degradation behavior is studied by TGA-DTA technique in Nitrogen atmosphere and found the main degradation phase between 200-600°C which is further divided into two phases one from 200-400°C and 400-600°C for the thermal disintegration of different components. The kinetic and thermodynamic parameters are calculated by model free kinetics such as Friedman, KAS and OFW is done to describe pyrolysis behavior of refinery sludge by using TGA-DTA data. The effect of temperature (350°C, 400°C and 450°C) is studied through autoclave pyrolysis unit by keep feedstock, pressure, and agitation conditions constant. In lab scale pyrolysis process, highest bio- oil yield was achieved at 450°C. The products such as dry sludge and gasses are further analyzed by proximate, ultimate and TGA analysis. These all results are in complete agreement with the research already conducted by researcher all around the world. Our thermodynamics parameters and model free kinetics will provide basis for future researcher to design equations of simulation base study of oil refinery sludge and predicts the gaseous products and volume of residual produced from oily sludge sample.