Study On Oily Sludge Treatment By Potassium Ferrate Conditioning-cleaning Agent

The treatment of oily sludge is a worldwide problem,and the recovery of crude oil from oily sludge is also a research hotspot for sustainable development.Thermochemical cleaning technology has the advantages of simple operation,fast efficiency and low cost,and is suitable for the resource treatment of oily sludge.However,the processing depth of this process is not enough,and it needs to be used in conjunction with other technologies.Chemical conditioning can be used in the pretreatment stage of thermochemical cleaning technology.Potassium ferrate is a green strong oxidant with multiple functions,which has been proved to be used for sludge dewatering.Its strong oxidizing property can destroy the viscous shell and greatly improve the oil removal effect.In this paper,the physical and chemical properties of oily sludge will be studied first,and then the improvement of dewatering and deoiling of oily sludge by potassium ferrate conditioning will be studied.Finally,through the screening of cleaning agents and the effect experiments of conditioning cleaning,the optimal agents and optimal experimental parameters were determined.Among them,the working parameters are optimized through single factor experiment and orthogonal experiment.In addition,the changes of hydrocarbons before and after thermal cleaning of oily sludge were studied by thermogravimetric analysis and total hydrocarbon analysis.This study shows that:（1）The water content,oil content and solid content of oily sludge are 5%～11%,20%～30%and 60%～70%respectively;The particles larger than mm account for 54.69%;the content of saturated hydrocarbons,colloids,aromatic hydrocarbons and asphaltenes are 66.85%,21.31%,17.98%and 3.37%respectively;the main mineral components of mud are quartz（Si O₂）,calcite（Ca CO₃）.)and albite（Na（Al Si₃O₈））,the relative mass contents were 58.60%,27%and14.40%,respectively;the fluidity of the oil adhering to the sludge surface decreased rapidly in the range of 40～60℃;（2）Potassium ferrate can improve the dehydration of oily sludge,and it has a good effect at 8g/L;infrared spectrum analysis shows that potassium ferrate conditioning is beneficial to the oxidation of unsaturated hydrocarbons in oily sludge and adhesion to the sludge.Removal of crude oil on the surface;the best conditioning parameters are:temperature 35℃,p H=6,mud-water ratio 1:5 and stirring time 30min;（3）The oil removal rate of 91.71%can be obtained by compounding TX-100 and AOS in a ratio of 3:1,while a single dose of TX-100 is only 87.6%.However,considering economic reasons,a single dose of TX-100 is selected as The best agent;the best cleaning concentration is 3g/L,and the best conditioning concentration is 8g/L;thermogravimetric analysis shows that the heavy components in the treated oily sludge are oxidized or removed by cleaning,and the organic volatile substances It is removed by a large amount of oxidation;the analysis of all hydrocarbons shows that the light oil of the sludge after conditioning and cleaning can be completely removed,and the heavy components can be affected by strong oxidation;the order of the influence of each factor on the treatment effect is:oil washing Temperature>p H>stirring time>mud-water ratio;the optimized experimental parameters of orthogonal experiment are:p H=6,mud-water ratio is 1:5,oil washing temperature is 60℃,and stirring time is 30min.