Experimental Study On Pyrolysis Of Oily Sludge And Its Residue Preparation For Roadbed Materials

Oily sludge is a kind of solid waste formed by the adhesion and penetration of petroleum substances in the process of petroleum exploitation,refining,storage and use.Pyrolysis is an effective method for treating oily sludge.Pyrolysis has the advantages of large processing capacity,complete treatment,high capacity reduction,recovery of crude oil,no secondary pollution,etc.It is one of the effective ways to realize the resource and harmless of oily sludge.The pyrolysis residue of the oily sludge is the solid material remaining during pyrolysis,and a large number of stacking causes some problems.Oily sludge pyrolysis residue is the residual solid matter during pyrolysis.In this paper,the pyrolysis residue of oily sludge was used as raw material to prepare stable materials by adding cement,fly ash and sodium sulfate.The effects of heating rate on the pyrolysis process of oily sludge were studied by thermogravimetry-infrared-mass spectrometry.The XRD of the oily sludge and the XPS and XPS of the sulfur were analyzed at different pyrolysis temperatures.Test results: The pyrolysis process of oily sludge can be divided into three stages: evaporation of water and light organic matter,pyrolysis of organic matter and decomposition of inorganic carbonate,decomposition of long-chain stable organic macromolecules such as heavy oil;Increasing,the trends of TG and DTG curves are basically similar,the pyrolysis process produces hysteresis phenomenon,the pyrolysis rate increases,the pyrolysis process shortens,and the final mass loss of pyrolysis is small;The gas produced in the pyrolysis process is offset to high temperature with the increase of the heating rate.Different gases are not completely affected by the heating rate.During the pyrolysis process,the sulfur compounds change.Making use of oily sludge pyrolysis after pyrolysis residue as raw material,adding cement,fly ash and sodium sulfate to prepare stable materials,through unconfined compressive strength,water stability test,dry-wet cycle test,dry shrinkage test,frost resistance test and water permeability test,the effects of cement,fly ash and sodium sulfate on it were studied.Test results: When the cement content increases from 2% to 6%,the unconfined compressive strength increases,the water stability coefficient K increases,the K value is greater than 0.8,the water stability is better;the dry shrinkage strain and the drying shrinkage coefficient increases,that is,the stable material is prone to cracks and shortens the service life;after the wet and dry cycle,the loss rate of compressive strength decreases,the water permeability coefficient also decreases and the frost resistance performance is improved.With the increase of fly ash content(10%~30%),the unconfined compressive strength first increases and then decreases;through the above test results,when the fly ash content is 20%,the performance of the stable material is best.With the increase of sodium sulfate content(0.3%~0.9%),the unconfined compressive strength of the stabilized material increases.When the sodium sulfate content is 0.6%,the compressive strength increases fastest;the water stability coefficient increases,and the water stability is enhanced.Dry shrinkage strain and drying shrinkage coefficient are reduced,water permeability coefficient is also reduced,drying shrinkage and water permeability resistance are improved;loss rate of compressive strength is reduced after dry-wet cycle and freeze-thaw cycle,dry-wet cycle and resistance,The enhanced freezing performance extends the service life of the stabilized material.It can be seen from the experiment that the addition of sodium sulfate can improve the performance of the stable material.