The Investugation On Preparation And Properties Of Oil Dechlorination Adsorbents

With the increasing deterioration,heaviness of crude oil and the addition of oil recovery aids,the content of organic chlorine-containing compounds in oil products continues to rise in recent years.In addition,organic chlorine-containing compounds are difficult to remove in electrical desalination.Therefore,it is significance to carry out research on the removal of organic chlorine-containing compounds in oil.In this paper,adsorption dechlorination with industrial development prospects was selected.Through the screening of adsorbents and metal modification,a series of dechlorination adsorbents with excellent dechlorination effect were successfully prepared,and static adsorption dechlorination was carried out on them.On the basis of chlorine performance evaluation and process optimization,the adsorption equilibrium and adsorption thermodynamics of the screened Zn-13X adsorbent were studied.The specific research contents are as follows:1.The adsorbents were screened by static adsorption experiments,and the Na-Y molecular sieve with the best adsorption effect was metal-modified.We mainly investigate the effect of modified metal species（Ni,Co,La,Ce）,metal content and different modification methods（equal volume impregnation method,ion exchange method,impregnation precipitation method）on the dechlorination performance of the adsorbent.The results show that the Ni-Y adsorption dechlorination agent prepared by the immersion precipitation method under the Ni（NO₃）₂ concentration of 0.05 mol/L has the best effect.The dechlorination agent can remove 82.12%of 1,2-dichloroethane under the condition of static adsorption for 4 h at 30℃,1:40 agent-oil ratio.The prepared adsorption dechlorination agent was characterized by XRD,SEM,low-temperature nitrogen adsorption and desorption,NH₃-TPD and other methods.2.The 13X molecular sieve was modified by series of metals by dipping and precipitation method,and its adsorption and dechlorination performance was investigated.The results show that the 13X molecular sieve adsorbent modified by Zn had the best dechlorination effect.The adsorbent prepared with 0.1 mol/L Zn（NO₃）₂,calcination temperature of 450℃and calcination time of 4 h had high dechlorination rate.The dechlorination rate of 1,2-dichloroethane reached 95.5%after static adsorption for 4 h at the agent-oil ratio of 1:40 and the adsorption temperature of 30℃.Finally,the prepared adsorption dechlorination agent was characterized and analyzed by XRD,SEM,low-temperature nitrogen adsorption and desorption,NH₃-TPD and other methods.3.The adsorption equilibrium and adsorption thermodynamics were studied on the Zn-13X adsorbent.By fitting the adsorption isotherm to the experimental data of the adsorption process of 1,2-dichloroethane,the relevant thermodynamic parameters were obtained.The results show that the Langmuir adsorption isotherm can well describe the adsorption behavior of 1,2-dichloroethane on Zn-13X adsorbent.At different temperatures from 303.15 K to 333.15 K,the saturated monolayer adsorption capacities of 1,2-dichloroethane on Zn-13X adsorbent were 37.24 mg/L,44.21 mg/L,50.99 mg/L and 56.27 mg/L,respectively.The average value ofΔH~0 in the adsorption dechlorination process of Zn-13X adsorbent was 11.64 k J/mol,the average value ofΔS~0 was 42.15J/（mol·K）,andΔG~0 was negative.From the perspective of thermodynamics,the removal of 1,2-dichloroethane by Zn-13X adsorbent is an endothermic,spontaneous,disordered and dominated by physical adsorption.