Reactor temperature control in hydrocracking units

By adjusting the outlet temperature of the feed heater, and thereby adjusting the reactor inlet temperature； By adjusting the cold hydrogen injection rate into the catalyst bed ； Keep the temperature rise of the catalyst bed within a reasonable range. During the operation, it is necessary to strictly adhere to the operating principles of \"increasing the volume first and then raising the temperature, and reducing the volume first and then lowering the temperature.\" Hydrocracking is a highly exothermic reaction. Generally, the heat of reaction in hydrocracking is balanced by the heat carried away by the reaction stream from the catalyst bed; as a result, under normal conditions, the temperature of the hydrocracking catalyst bed remains stable. If, for some reason, the heat carried away from the catalyst bed by the reaction stream is less than the heat generated during hydrocracking, this imbalance, if not detected in time or not addressed properly, can lead to a chain reaction of temperature rise – rapid heat release – and further sharp increases in temperature, posing a serious threat to personnel, equipment, and the catalyst. To meet the requirements of such special emergency situations, the reaction system of the hydrocracking unit is equipped with emergency pressure relief systems operating at 0.7 MPa/min and 2.1 MPa/min. If the 0.7 MPa/min system is activated and the temperature still cannot be controlled, and if either the reaction temperature exceeds 28°C above the normal level or the temperature reaches 427°C, the unit must immediately release pressure at a rate of 2.1 MPa/min. Finally, rapid venting is used to remove a large amount of heat and terminate the reaction, thereby achieving a temperature reduction.