Thermochemical Cleaning And Metal Element Analysis Of Oil Sludge

In this thesis,carboxymethyl cellulose（CMC）（low viscosity）was used as stabilizers,a novel methyl methacrylate（MMA）-butyl acrylate（BA）-acrylic acid（AA）grafted carboxymethyl cellulose copolymer emulsion was synthesized by emulsion polymerization under the condition of moderate degree of acrylic acid.Thermochemical cleaning combined with hot steam air floatation process was developed to treat oil sludge.The sludge and metal elements were compared and analyzed before and after treatment.The results are as follows:The P（MMA-BA-AA）/CMC copolymer emulsion has good demulsification effect,the demulsification of high water-bearing oil emulsion can be realized within 25 min after 1:3 dilution.For cleaning oil sludge,the optimum formula of emulsion was obtained by taking the oil content of solid phase after cleaning as the evaluation standard（300 g as an example）:the CMC dosage was 1.0 g,total monomer 25%,MMA,BA mass ratio of main unit is 1:3,the AA amount of functional monomer was7.5 g,neutralization is 1/2,the initiator is 3‰of the total amount.The polymer emulsion with good cleaning effect and stable performance can be obtained.The effective particle size of emulsion is mainly distributed in the range of 480～700 nm.Treatment 40 g oil sludge with 10 g emulsion and 0.1 g Na₂Si O₃,the best thermochemical cleaning combined with hot steam air floatation process is:solid-liquid ratio 1:3,cleaning temperature 80℃,stirring rate200 r/min,cleaning time 2 h,static heat preservation 15 min,hot steam floatation 1.5 h.The oil content of the oil sludge was decreased to about1.5%after cleaning,reaching the Q/SY LH 0533-2016 treatment standard.After treatment,the physical properties of the sludge have not changed obviously,the pore structure of the soil is clear,and the goal of resource and harmless treatment of the sludge is realized.The quantitative analysis of eight metal elements（Ba,Pb,Cu,Zn,Mn,V,Fe,Sn）in oil sludge before and after cleaning shows that the Pb content in untreated oil sludge exceeds the control value and the heavy metal exceeds the standard.The thermochemical cleaning will promote the migration of metal elements due to three-phase separation.After cleaning,the Zn,Fe content in the solid phase will be reduced by about 50%,the Ba,Cu,V,Sn content will be reduced by more than 25%,and the Pb,Mn will be reduced by nearly 10%.The results show that thermochemical cleaning combined with thermal steam floatation can significantly reduce the content of sludge metal and further avoid the risk of heavy metal pollution after treatment.