Study On Preparation Of Dechlorination Agent For Catalytic Reforming Oil Based On Physicochemical Synergistic Effect

In recent years,due to the high water content of crude oil,high wax content,heavy quality,inferior quality and the addition of chlorine-containing oil production additives,the content of organic chloride in oil products has increased significantly,which brings great challenges to oil processing.Catalytic reforming is a secondary processing process in which the organic chloride in raw naphtha is generated into inorganic chlorine through the pre-hydrogenation system,which will cause corrosion to the reforming equipment and affect its formation and operation.Therefore,it is particularly important to carry out effective research on inorganic chlorine removal.This thesis aims to explore the adsorption dechlorination technology which has the prospect of industrial development.The dechlorination adsorbent was prepared by physical adsorption,chemical adsorption and physical-chemical synergistic effect,and the static adsorption dechlorination performance was evaluated and the process optimization was made.At the same time,the adsorption equilibrium,kinetics,activation energy and thermodynamics are also discussed.Finally,based on the static adsorption experimental data,dynamic adsorption simulation is made to provide guidance and suggestions for the actual process.The main research contents and conclusions are as follows:（1）Using KOH as activator and anthracite as raw material,coal-based activated carbon was prepared through activation carbonization and other processes.Through SEM image analysis,coal-based activated carbon has a clear outline and no ash impurities.Ca CO₃ and Cu O were the active components of dechlorination agent.Ca-Cu adsorption dechlorination agent was prepared by blending method.SEM and TEM images showed that Ca CO₃ and Cu O were uniformly distributed,attached to each other and did not agglutinate.The introduction of Ca CO₃improved the thermal stability of Ca-Cu adsorption dechlorination agent.XRD images showed that the active components Ca CO₃ and Cu O in Ca-Cu adsorption dechlorination agent had high crystallinity and no impurity peaks.Using coal-based activated carbon as the carrier and Ca CO₃ and Cu O as the active components,the blending AC/Ca-Cu adsorption dechlorination agent was prepared by blending method.SEM and TEM images were used to analyze the adhesion of Ca CO₃ and Cu O can effectively adhere to the surface of coal-based activated carbon with uniform dispersion without agglomeration,high thermal stability and high crystallinity of active components.（2）When the ratio of agent to oil is 10g/L and the temperature is 313.15K,the dechlorination rate of coal-based activated carbon reaches 58%～60%after 6 hours of static adsorption.The dechlorination rate of Ca-Cu adsorption dechlorination agent can reach 93%～94%under the conditions of the ratio of agent to oil of 6.67g/L,adsorption time of 5 hours and temperature of 313.15K.When the ratio of agent to oil is 11.67g/L and the temperature is313.15K,the removal rate of AC/Ca-Cu dechlorination agent can reach 98%for adsorption time of 5 hours.（3）Langmuir adsorption isotherm can well describe the adsorption behavior of HCl on coal-based activated carbon,Ca-Cu adsorption dechlorination agent and blended AC/Ca-Cu adsorption dechlorination agent.The adsorption process of HCl on the three dechlorination agents conforms to the quasi-second-order kinetic model.Coal based activated carbon adsorption HCl Gibbs free energy change is negative,DG^°average adsorption activation energy of 7.456 k J/mol,combined with the adsorption thermodynamics data analysis and the activation energy of coal based activated carbon adsorption HCl is weak endothermic and spontaneous physical adsorption process;Ca-Cu adsorption dechlorinating agent Gibbs free energy change of HCl DG^°is negative,adsorption activation energy of 44.802 k J/mol,combined with the data analysis of adsorption thermodynamics and adsorption activation energy Ca-Cu adsorption dechlorinating agent adsorption process is endothermic HCl,spontaneous and is chemical adsorption process.Blending AC/Ca-Cu adsorption dechlorinating agent HCl Gibbs free energy change is negative,DG^°average adsorption activation energy of 36.486 k J/mol,According to the data of adsorption thermodynamics and activation energy of adsorption,HCl adsorption by blending AC/Ca-Cu adsorption dechlorinating agent is an endothermic reaction that can be carried out independently without the help of external factors.It is also a process of chemical adsorption and physical adsorption interaction.（4）Based on static Adsorption experimental data,using Aspen Adsorption to simulate dynamic adsorption.The results show that the simulation results of dynamic adsorption of HCl by dechlorination agent are basically consistent with the static adsorption experiment results.The penetration time of the bed is significantly advanced with the increase of feed concentration and flow rate,but the maximum adsorption capacity of the bed is not affected by the feed flow rate.When the mass transfer coefficient is less than 0.1s^-1,the dynamic adsorption effect is greatly affected.