| The trace amount of sulfur/nitrogen/oxygen heteroatomic organic compounds in oil make environmental protection and circular economy face severe challenges.On the one hand,the consumption of white oil for fine chemical industry and transformer oil for power industry reached 800 and 400 kilotons per year respectively.The existence of organic sulfide,such as mercaptan,thioether and disulfide,not only has a foul odor,but also affect the stability of products,resulting in the formation of colloid and precipitation,corrosion of metal equipment,poisoning and failure of catalysts,and accidents.In view of the bottleneck problem of low selectivity of deep desulfurization adsorption at the present stage,this dissertation proposes to develop the oxidation and adsorption coupling deep desulfurization process of catalytic and adsorption bifunctional materials at room temperature and atmospheric pressure,so as to achieve the goal of highly selective deep adsorption removal of various organic sulfur.On the other hand,the consumption of lubricating oil in China is more than 6 million tons per year,and a large amount of waste oil is formed after use.The current direct dumping,burial or acid-base washing and other treatment methods cause serious harm to soil,water quality and life.Recycling and reuse in a green way is of great significance to improving the utilization rate of existing resources,economic value and protecting the ecological environment.Aiming at the demand of efficient removal of heteroatomic organic compound impurities in waste lubricating oil,this dissertation proposed to study the oxidation-adsorption decolorization and regeneration process of waste lubricating oil,so as to realize the goal of efficient adsorption and decolorization resource reuse of waste lubricating oil.Based on the previously developed oxidation-adsorption coupling process for deep removal of diesel thiophene sulfur,this study further explored the effectiveness of this coupling process for enhanced deep adsorption removal of various other organic sulfur（mercaptan,thioether and disulfide）.First of all,Ti（2.5%）-MCM-41 catalytic-adsorption bifunctional material was developed.Compared with the single physical adsorption desulfurization,the desulfurization rate and saturated adsorption capacity of the four organic sulfur were greatly improved by this process,and the desulfurization rate is all>90%,in line with Langmiur adsorption isotherm model,saturated adsorption capacity reached 22.2mg-S/g-A（n-propyl mercaptan）,102.0 mg-S/g-A（dimethyl sulfide）,24.1 mg-S/g-A（ditert-butyl disulfide）and 24.4 mg-S/g-A（dibenzyl disulfide）.The adsorption equilibrium constant k increased by 1～2 orders of magnitude,and the effect was significantly higher than that of other adsorbents with the same use.Then,in the fixed bed dynamic desulfurization process,the sulfur content in real transformer oil with initial dibenzyl disulfide content of 150,50 and 10 ppm can be reduced to<0.2 ppm,when the corresponding penetrating sulfur content is 10,10 and 1 ppm,the real transformer oil processing capacity is up to～210,530,2050 L-oil/kg-adsorbent,to meet the needs of efficient and deep desulfurization.By analyzing the catalytic oxidation products and calculating the adsorption selectivity,it was found that with the presence of oxidants,organic sulfide catalyzed oxidation on the catalytic site of Ti O2generated sulfoxide,sulfone and sulfonic acid and other highly polar products,which were adsorbed by Si-OH adsorption site with high selectivity.Finally,the properties of Ti-MCM-41materials can be recovered completely by solvent elution and air thermal oxidation regeneration,and the desulfurization rate is>90%.In addition,a semi-continuous catalytic oxidation adsorption-regeneration deep desulfurization cycle was proposed.A new process of high efficiency decolorization and impurity removal of waste lubricating oil coupled with oxidation and adsorption was studied in this paper.First of all,the deterioration mechanism and reason of waste lubricating oil were described.The color-developing substances were extracted by using NMP as extractant,and the analysis shows that the chromogenic substances are colloid and asphaltene substances with strong colouring ability,as well as the deterioration products of additives containing chromogenic groups（C=O,N=N,C=C,N=C and polyaromatic rings）or the additives themselves.Then,the effects of adsorbent types,reaction temperature,dosage of oxidizer,stirring time and adsorbent addition amount on the performance and yield of decolorized oil were explored,and the better operating conditions were obtained:activated alumina is used as adsorbent,the reaction temperature is 90?C,the dosage of oxidant is 1.0%,the reaction time is 60 min,and the mass ratio of agent to oil is 3%.The performance of waste lubricating oil was improved obviously,from black brown to yellow brown,the pungent smell became light,the decolorization rate and the total yield were 54.2%and 90.8%,respectively,the chroma decreased from 8 to 4,the mass fraction of sulfur decreased from 0.2%to 0.06%,and the acid content decreased.In addition,the mechanism of coupling decolorization and impurity removal was explained,and the process design and economic evaluation were carried out,which showed that the process has better decolorization effect and economic feasibility. |
