Transformation Process And Technology Research Of Oily Sludge By Microwave Heating

Oily sludge is a hazardous solid waste, which generated in petroleum exploitation, storage and transportation of crude oil, crude oil refining and petrochemical production, if not effectively treated will cause environmental pollution and waste of resources. With the rising cost of processing and requirements for the energy-saving society, oily sludge recycling treatment becomes increasingly important.In this paper, the oily sludge treatment by microwave technology was studied. Firstly, the conversion process of oily sludge treatment by microwave heating was studied, revealing the law of the conversion process and kinetics simulation analysis. Secondly, using scale-up equipment carried out the comparison test of microwave and electric, Confirmed the advanced of microwave technology. Operating parameters such as feed temperature and feed rate were optimized by microwave heating continuous treatment tests. Finally, the feasibility of the microwave heating treatment process being analyzed from safety, environmentally friendly and economic.Under microwave irradiation, the conversion process of oily sludge treatment can be divided into4stages:oily sludge drying (room temperature-140℃), light hydrocarbons evaporate (140℃-300℃), pyrolysis reaction (300℃-500℃), the depth of cleavage (550℃-800℃). Compared with electric heating, faster heating rate and weight loss rate were found in microwave technology and the reaction temperature range of pyrolysis became wider. Kinetics simulations found that microwave pyrolysis reaction range was300℃-550℃, activation energy was15.69KJ/mol, significantly lower than the electric pyrolysis simulation results, showing that the catalytic cracking reactions of microwave. Microwave pyrolysis ultimately temperature and the main reaction range were determined, providing a basis of the scale-up oily sludge treatment test by microwave heating.The scale-up experiments showed that microwave heating could act directly on the material system, improving the efficiency and greatly reducing the processing time, only38.6%of the electric treatment time. The strong penetrating power could make the temperature of oily sludge more uniform, sludge drying and pyrolysis stage more synchronized, and eliminating the temperature gradient can reduce the occurrence of side effects. The analysis of the pyrolysis products found that the "non-thermal effects" of microwave pyrolysis could improve the recovery of oil and non-condensable gas. The recovery rate of oil was83.4%and the quality of oil was improved. In continuous microwave test, when the microwave power was20kw and pre-feeding quantity of oily sludge was4kg, the optimum operating conditions were:feeding temperature (450℃-550℃), microwave absorber (3%), continuous feeding rate (8kg/h).In this case, the time required for unit mass of sludge treatment is only22.7%when treated with electric and oil recovery increased to85.1%. Microwave continuous treatment of oily sludge running smoothly had a great significance for industrial promotion.Microwave heating treatment was fully in line with the industrial applications require, which could greatly reduce energy consumption and improve the calorific value of the oil recovered. Overall, the microwave heating treatment process and equipment units were reliable and could achieve oily sludge resources treatment, having superior prospects for industrial promotion.