0.7MPa chain relief valve

It’s not only the UOP process that features high and low speed pressure relief; most hydrocracking processes work in this way as well. We use the UOP process. The 7 bar pressure relief is primarily triggered by the shutdown of the circulation pump and low feed levels to the reactor; in other words, when the reactor lacks a means to remove the heat generated by the reaction, pressure relief is used to prevent the temperature from rising too high. The 21 bar trigger, on the other hand, occurs when the reactor temperature becomes excessively high. It can be seen that the conditions for triggering these mechanisms are more stringent. . A comparison of the two shows that a pressure release of 21 is likely to cause greater damage to the reactor bed and similar components than one at 7 bar. Therefore, two pressure relief states are set to protect the catalyst. This is my personal understanding; I hope it helps you.

I agree with what was said above; the two pressure relief modes are designed to remove heat through pressure release in order to prevent overheating. It prevents equipment from experiencing catastrophic failures due to overheating or overpressure. There are few opportunities to use it; if it has to be activated, it may cause fluctuations in the catalyst bed, leading to issues such as flow deviation and increased pressure drop, which can affect production. (We have been in operation for many years, and we have never activated the emergency pressure relief system for self-protection.) Appendix: Typical automatic interlock shutdown system for hydrogenation emergency pressure relief: The device is equipped with a manual emergency pressure relief interlock shutdown system set at 0.7 MPa/Min, as well as another manual emergency pressure relief interlock shutdown system set at 2.1 MPa/Min. 0.7MPa/Min manual emergency pressure relief interlock shutdown system: Activation conditions: *An emergency occurs within the unit: fire, reactor over-temperature, etc. Interlock actions: *The hydrogen feed pump stops operating; *The reaction feed heater shuts down; *The high-pressure lean solvent pump stops operating. In addition, when the 0.7MPa/Min manual pressure relief is activated, the new hydrogen compressor and the recycle hydrogen compressor also stop operating. 2.1MPa/Min manual emergency pressure relief interlock shutdown system: Activation conditions: *An emergency occurs within the unit: reactor bed temperature exceeds 420°C, fire breaks out, etc. Interlock actions: *Hydrogen feed pump stops operating *Reactor feed heater shuts down *High-pressure lean solvent pump stops operating. In addition, when the 2.1MPa/Min manual pressure relief is activated, the new hydrogen compressor and the recycle hydrogen compressor also stop operating.

Why must the cyclohydrogen compressor be stopped for a 0.7 pressure relief? Could what I’m seeing be a fake UOP process package? Besides, is it convenient to transfer heat when the circulating hydrogen is stopped? Does it help in heating the reaction system?

We manually operate the circulation pump at 7 bar to keep it running; it starts automatically when the pressure drops to 7 bar.