| In the ethylene oxide/ethylene glycol plant, ethylene epoxidation reactor is an important equipment of the oxidation reaction part. Because of extreme operating environment such as high temperature and high pressure as well as complex coupling effects of potential risk factors, the reactor tends to be operated in abnormal condition, and the temperature may runaway, so that when the parameters change, it may be followed by serious accidents. In order to study the mechanism of reactor temperature runaway and prevent accidents, this paper has identified the potential risks, analyzed the operation parameters which influenced the reaction running states by using Hazard and Operability Analysis (HAZOP) method. Then the working process in the reactor is simulated by using FLUENT software to monitor the distribution of components and temperature dynamically. Based on those simulation results, the influence of operation parameters fluctuation on the heat balance and operation effect in the reactor are analyzed, and mechanism of temperature runaway leading to accidents has been proposed. Finally, according to risk analysis results, influences of parameter fluctuations and process safety management, this paper builds an information guidance system to prevent temperature runaway accidents, and provide technical basis for prevent ing the accidents. The main contents are as follows:(1) The HAZOP method has been applied to identify the potential risks resulted in reactor temperature runaway accidents. Taking the "temperature in reactor bed layers is too high" as deviation, then the causes, results, corresponding safety measures and suggestions for the deviation are analyzed. By analysing the risk level of each risk factor, the most important operation parameters and operating steps can be ascertained.(2) This paper has simulated the operating process dynamically under normal operation condition by FLUENT software. Based on the simulation results,7 factors and 6 variables are selected to conduct the single factor influence tests. And the influence of reactor parameter fluctuations on the heat balance and operation effect has been analyzed. Combined with the high temperature alarm and production efficiency of reactor, the sensitive area and suitable operation scope of parameters can be determined. Analysis results shows that the higher ethylene concentration, oxygen concentration, feed flow rate, feed temperature, drums temperature, operating pressure and smaller porosity can improve the temperature and the reaction rate in the bed layers. Ethylene concentration, oxygen concentration, drum temperature and porosity have more efficient influence on temperature runaway accidents, which need more monitoring. And feed temperature, feed flow rate and operating pressure have limited effects.(3) Taking the nodes, equipment and deviations of HAZOP analysis as objects, based on the HAZOP risk analysis results and parameters fluctuation influence research, combined with process safety information classification management, this paper has built the ethylene epoxidation reactor information guidance system to prevent temperature runaway accidents. This system can monitor, predict, and analyse possible abnormal conditions and results caused by parameter fluctuations. Process technical data can be located and referred quickly and easily. This can help emergency decision-making, and provide information guidance to prevent the reactor temperature runaway accidents.According to risk analysis, simulation of parameter fluctuations influence and process safety management, causing mechanism of temperature runaway accident for ethylene epoxidation reactor has been studied, and an accident prevention information guidance system has been built, which provides technical basis for temperature runaway accident prediction and ensuring the reactor operating safely and efficiently. |
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