Feasibility Study Of STAR Technology Applied To Oily Sludge Treatment

With the rapid growth of the global economy,oil continues to be widely exploited and used as a major energy source.Environmental pollution in the process of oil exploration,exploitation,smelting,processing and transportation is becoming more and more serious.The oily sludge,referred to as "sludge",is more and more harmful to the living environment of human beings and has been listed as national hazardous waste.The annual amount of oil sludge is about 160 million tons,and the global accumulated amount of oil sludge is more than 1 billion tons.The composition of oil sludge is extremely complex,usually containing a large number of crude oil,heavy metals,BTEX,asphaltene,ceresin wax,phenols,anthracene,solid suspended matter,pyrene and other toxic and harmful substances.If not properly disposed,it will pose a serious threat to the ecological environment and human health.Are commonly used in sludge treatment technology has certain advantages and disadvantages,the STAR(Self-sustaining treatment for active remediation)technology as a newly developed technology,for the treatment of solid waste has a certain potential,STAR technology is based on the principle of solid smoldering,It is an exothermic oxidation reaction occurring in the condensed phase on the surface of the fuel.It is a slow,low-temperature,flameless combustion form.A short input of heat can maintain the continuous combustion of pollutants until the end of the reaction,which has the advantages of low treatment cost,short repair time and high removal efficiency.On the basis of previous studies,aiming at the problems of low carbon content of crude oil in specific areas,low smouldering peak temperature,low removal rate,and inability of smouldering sludge with low oil content,this paper discusses the factors affecting the preparation of smouldering sludge through the STAR reaction device built by itself,and studies the improvement of peak smouldering temperature of oil sludge by using activated carbon to fuel low oil content sludge.Finally,the treatment effect of actual sludge is verified.The results show that:(1)The smoldering effect of oil sludge with river sand added is much better than that without river sand added.The pore distribution is more uniform and the permeability is better.Smouldering can not occur when the ratio of sludge to sand is 1:2,2:3 and oil content is lower than 5%.Smouldering can occur when the ratio of sludge to sand is 1:1～3:1,the oil content is 5%～15%,the particle size of river sand is 1～6 mm,and the air flow rate is 2.07～6.8 cm/s.The smouldering effect is the best when the ratio of sludge to sand is 2:1,the particle size of river sand is 2～4 mm and the air flow rate is 5.39 cm/s.The removal rate of total petroleum hydrocarbon is more than 98%,which meets the requirements of sludge treatment.However,the removal of petroleum hydrocarbons did not achieve the optimal effect,so activated carbon was introduced into the combustion aid research.(2)After the introduction of activated carbon combustion,coconut shell activated carbon particle size of 4～6 mm,add amount of 100 g/kg,columnar activated carbon particle size of 1.5 mm,add amount of 100 g/kg,its peak temperature is the highest,the average peak temperature reached700℃ or so,the best treatment effect,peak temperature appeared the shortest time,the types of toxic and harmful gases reduced.The removal rate of total petroleum hydrocarbon is more than 99%,which is also higher than that without activated carbon,the petroleum hydrocarbon content of oil sludge residue is between 330～650 mg/kg,which meets the requirements of oil sludge treatment and improves the treatment effect.(3)After adding activated carbon,low oil content sludge can also smoulder.When the amount of two activated carbon was 100 g/kg,the treatment effect was the best,the average peak temperature reached753.4℃,and the sludge was fully burned.The removal rate of total petroleum hydrocarbon is more than 99%,the petroleum hydrocarbon content of oil sludge residue is between 180～550 mg/kg,which meets the requirements of oil sludge treatment,and the treatment effect of columnar activated carbon is better than that of coconut shell activated carbon.(4)After the introduction of activated carbon,the smoldering effect of the actual oil sludge is also better,and the average peak temperature reaches 734.9℃,the removal rate of total petroleum hydrocarbon is more than 99%,the petroleum hydrocarbon content of sludge residue is between300 and 680 mg/kg,which meets the requirements of oil sludge treatment.Coconut shell activated carbon added amount of 100 g/kg,the treatment effect is the best,columnar activated carbon added amount of 100 g/kg and80 g/kg,the treatment effect is little difference,in order to save costs,the priority is to choose 80 g/kg activated carbon added amount,and the two kinds of activated carbon on the actual sludge treatment effect is little difference.