Hydrocarbon Recovery From Petroleum Sludge Using Microwave Reactor

Oily sludge is a complex dark brown, sticky hazardous solid waste generated during the crude oil secondary exploitation. It contains various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Because of its high oil content, petroleum sludge is considered to be hazardous to the environment and to human health. In recent years, much work has therefore focused on its treatment.Firstly, this paper introduces the physical and chemical properties of oily sludge, including the composition and its industry, elements and calorific value analysis. Azeotropic distillation method was used to measure the proportion of water, oil and residue in oily sludge. Four components determination of oily sludge was measured by column chromatography. The volatile, ash content and calorific value were analysed in this paper as well. These properties show that oily sludge has high recovery value and cannot be incinerated directly.This paper investigates the impact of microwave technique and centrifugal technology on emulsified water in oily sludge. DSC was used to analyze the water content and size distribution in the treated oily sludge. The results show that after centrifugal treatment, most of emulsified water in oily sludge are crushed from9.56～14.76μm size to5.75～6.99μm size, however it cannot be removed from the upper layer. But if use the microwave treatment firstly, the emulsified water in oily sludge can be removed effectively.The pyrolysis of oily sludge was studied by microwave reactor and tube furnace. The results shows that less solid residues (about19%) and more pyrolysis oil (about52%) can be produced by microwave reactor and the benzene content in the pyrolysis oil from microwave reactor is less than the oil from tube furnace. It shows that using microwave heat treatment can reduce secondary pollution. The activated carbon was used as microwave receptor to accelerate the process of microwave pyrolysis. The results shows that activated carbon can increase the heating rate of pyrolysis by50%, the final temperature increases from600℃to800℃, and the solid residues was less than the pyrolysis without activated carbon, pyrolysis gas increased to about38%.This paper studied the effect of activated carbon on the pyrolysis behavior of petroleum sludge under microwave irradiation. A mathematic method was proposed to calculate the microwave heating efficiency. The results showed that the heating rate of petroleum sludge was23.4℃/min and the solid residues produced from microwave reactor was about and liquid product was19%and52%respectively. Compared with the results of experiments without activated carbon, the heating rate of pyrolysis was increased by more than77%, the solid residues was decreased by24.7%and the gas product was increased by46.9%. As far as the heating efficiency of the microwave irradiation is concerned, it was increased by12%when10%of activated carbon was added while the efficiency was only16.6%without active carbon.