Technical Innovation And Operation Optimization Of Hydrotreating Unit Based On Whole Process Simulation

In recent years, with the world industry and economy developing rapidly, the demand of the oil and light fuel with high quality by countries around the world is daily on the increase. And with the continuous worldwide exploitation of the oil field, the supply of light and sweet oil is on the decrease, and the proportion of the heavy oil with high sulfur content in the exploitation crude oil is increasing. But now taking the environmental pollution and protection into consideration, the quality of gasoline, kerosene and diesel oil product should be improved. So the hydrotreating process play an important role in the whole refinery process, and recently domestic gasoline and diesel hydrotreating unit's capacity is continuously improved.Hydrotreating process can effectively reduce the content of sulfur, oxygen, nitrogen in the raw material, treat aromatics and olefins alternatively, remove metal and asphalt, and improve the quality of the product. Hydrotreating reaction mainly contains hydrogenated desulfurization, hydrogenated denitrogenation, hydrogenated deoxidization, and olefins and aromatic hydrogenated saturation. Hydrogenation reaction is an exothermic reaction, which needs high temperature and high pressure, and the unit energy consumption is high. So by adjusting the operating parameters, technically reforming process flow and optimization heat exchange network, the goal of energy conservation significantly can be achieved.This paper aims at an 800 thousand tons/year petrol and diesel hydrogenation unit in a certain refinery, simulates the whole process, and puts forward corresponding technical renovation and operation optimization. The main research contents and innovation features include the following three aspects:(1) Hydrotreating reactor simulation and parameter optimization:According to raw materials and product parameters and equipment and operating parameters in the actual production, using the hydrogenation lumped reaction kinetics model in HYSYS, hydrogenation reaction system is modeled. By checking the lumped reaction constant, the simulation result is consistent with the production results. Based on the model, analysis the influence of changing hydrogen to oil ratio and the reaction bed to the product, then guide the actual production.(2) Hydrotreating separation process simulation and operation tuning:simulate hydrotreating separation process, including high pressure and low pressure separation system, hydrogen sulfide removing column and fractionating column. Then three technical improvement schemes are proposed:1. Technical renovate the original process, and add two separation tank. The process energy consumption is sharply reduced.(3) Heat exchange network synthesis of hydrotreating process:analysis the original heat exchange network. After optimizing the network, cold utility is reduced by 27.7% and reacting furnace can be canceled. Redesign the heat exchange network after the process technically improved.