| During the development and production of petrochemical enterprises,drilling,operations,crude oil processing and storage,oily sewage treatment and other aspects has produced a lot of pollutants.As one of major pollutants,oily sludge is a kind of mixed system of sand and crude oil.How to treat oily sludge with less surplus sludge and harmless will become an inevitable trend in the development of sludge treatment and disposal technologies.The economic and effective disposal of oily sludge is of great significance to the sustainable development of oilfields and petrochemical companies.In this paper,the oil-containing sludge is the research object,which was dried by electro-osmosis dehydration process and negative pressure-microwave drying process.The influencing factors of deep drying of oily sludge were determined by single factor tests.The Orthogonal test was used to determine the optimal parameters and the drying effect.The drying kinetics and operating energy consumption were studied as well.The research contents mainly include the following aspects:1.The drying effect and dehydration mechanism of oil-containing sludge were studied on different parameters,such as,sludge thickness,voltage,current,and mechanical pressure.The response surface model was used to analyze the significance of electro-osmosis dehydration in oil-bearing sludge,which decided the optimal parameters for electro-osmotic dehydration: The voltage was 40 V,the mechanical pressure was 75 kPa,and the sludge thickness was 1 cm.The test data was brought into the commonly used thin layer drying model.As the Logarithmic model has higher correlation with electroosmotic dehydration test results under different conditions,so it can be used to predict the change of moisture content of oil-containing sludge during electroosmotic dehydration with time.In this way,electro-osmotic dehydration kinetic model for oil-containing sludge was established.2.The drying effect of oil-containing sludge was studied under different negative pressure-microwave device on different parameters,such as,sludge volume,microwave power,negative pressure.Orthogonal test was used to analyze thesignificance of negative pressure and microwave drying of oil sludge,and a multiple linear regression model was calculated.Origin software was used to fit the experimental data with commonly used thin layer drying models,analyzing the fitting results and verify their relevance.Finally,the optimum parameters for negative pressure and microwave drying were determined: microwave power was 700 W,sludge volume was 50 g,negative pressure was-0.06 MPa.The sludge drying kinetics model was established,which showed the logarithmic model has high correlation with negative pressure and microwave drying simulation providing support and basis for vacuum pressure-microwave drying process engineering application.3.The comprehensive efficiency of electro-osmosis and microwave combined with deep drying was explored.The influence of electro-osmosis on the subsequent drying of oily sludge was investigated through the negative pressure-microwave drying test of sludge after electroosmotic dehydration.Also,the response surface model and dynamic model were used to analyze the experimental data,and the feasibility of the joint drying process was explored in combination with drying energy analysis.The results were as follows: The moisture content of 1 t oily sludge reached58.65% under the optimal conditions of electroosmotic dehydration,the energy consumption was 379 kW·h either oily sludge with 80% moisture content consumes602.2 kW·h when it is treated with negative pressure and microwave drying to 40%,and the energy consumption is 468.0 kW·h when it is processed to 60% moisture content.This combined process can greatly save energy and reduce the cost of oil-containing sludge treatment,providing theoretical and technical support for the application of electroosmotic-microwave combined deep-drying process engineering for oily sludge. |
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