| With the poorer and heavier in quality of crude oil,a variety of chemical additives are used in the process of mining,transportation and processing of crude oil,these additives containing chlorine element would result in the chlorine content of crude oil increase constantly.And the impact of chloride in crude oil on petroleum processing is becoming severer.Chlorides in crude oil could be classified into two types: inorganic chlorides and organic chlorides.The conventional electric-desalting device for crude oil pretreatment can only remove inorganic chlorides in the crude oil effectively,but hardly remove organic chlorides in crude oil.Therefore,it is necessary to develop the effective dechlorination technology which process better dechlorination ability for the deeply pretreatment of crude oil dechlorination.Firstly,six kinds of organic chloride,such as carbon tetrachloride,epichlorohydrin,1-chlorine heptane,2-Chlorotoluene,1,2,3-chemical propylene and 5-chloro-2-methylaniline were selected as model organic chlorides in this paper.The thermodynamic analysis for the hydrolysis reaction under the condition of electric desalting operation was carried out,respectively.The analysis results illustrated that the above-mentioned reaction could be processed spontaneously,since the gibbs free energy change of organic chloride hydrolysis reaction was both less than zero,under the condition of 105~150? and 0.6~1.5MPa.Secondly,the six kinds of model organic chlorides were dissolved in straight-run diesel oil to prepare the simulated oil with certain chlorine content,respectively.According to the principle of phase transfer catalysis and the mechanism of nucleophilic substitution reaction,the novel type of dechlorination agent was developed in this work.The dechlorination experimental results for single chloride illustrated that under the same experimental conditions,chloride removal rate in order of from high to low was epoxy chloropropane,1,2,3-three chlorpromazine,1-chloro-heptane,2-chlorotoluene,5-chloro-2-methylaniline and carbon tetrachloride.And when the dosage of dechlorination agent was 300?g/g,the removal effect for single chloride was better.The dechlorination experimental results for mixed chloride illustrated that the removal rate of chlorides was 51.4% when the proper dosage of dechlorination agent was 300?g/g.As the rise of reaction temperature,the removal rate of chloride enhanced,and the removal rate of organic chloride can reach to 59.6% under 150?.When the reaction time was 90 min,the removal rate of organic chloride was 48.8%.Finally,three types of crude oil sample,from Sichuan,Zhongjie and Yanshan Petrochemical Company,respectively,were used as the investigation objects.According to the related standards,the properties of these crude oil sample were determined.The analysis results demonstrated that the total chloride content of Sichuan crude oil up to 20.424mg·L-1,its organic chlorine content was 14.714mg·L-1 and the inorganic chlorine content was 5.710mg·L-1.The total chloride content of Zhongjie and Yanshan Petrochemical crude oil was 7.422mg·L-1 and 10.177mg·L-1,respectively.By the experiments of bottle test and electrical desalting test,the proper type of demulsifier and its dosage for different type of crude oil were determined.Based on the principle of phase transfer catalysis and the mechanism of nucleophilic substitution reaction,a series of dechlorination agents for crude oil were developed and their dechlorination performance was evaluated by the SH-II electrical desalting instrument.The dechlorination experimental results demonstrated that the proper type of dechlorination agent for Sichuan crude oil was F type of dechlorination agent.When the dosage of F type of dechlorination agent was 180?g/g,the removal rate of total chlorine could reach at 66.4% and organic chlorine removal rate was 52.5% for Sichuan crude oil;The removal rate of total chlorine and organic chlorine for Zhongjie crude oil could reach be up to 67.45% and 52.67%,respectively with the 90?g/g dosage of F type of dechlorination agent;When the dosage of F type of dechlorination agent was 105?g/g,the reduction rate of chlorine element for Yanshan crude oil was lower,the total chlorine removal rate was 47.07% and organic chlorine removal rate only was 36.23%.Compared with the reduction rate of chlorine element of Sichuan and Zhongjie crude oil,it was found that the dechlorination effect for Yanshan crude oil is significantly poorer by using the F type of dechlorination agent. |
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