Heating of the hydrogenation unit
Thread Content
I would like to ask: when the temperature at the inlet of the reactor in the hydrogenation unit is raised to 130°C, the system pressure must not exceed 2.1 MPa. What factors are primarily taken into account here? After the temperature of all reactor walls exceeded 50°C, the system was pressurized to 2.5 MPa at a pressure increase rate of 1.0 MPa/h. What aspect is this taking into consideration again? In general, I think the factor of hydrogen embrittlement should be taken into account. So, when testing emergency pressure relief valves, should these conditions be considered as well?
In hydrogenation units, the key lies in testing the equipment and catalysts； During the startup and heating phase, it is necessary to take into account the hydrogen embrittlement temperature of the 15CrMo material (Nelson curve). Generally, the wall temperature should remain below 95 degrees, and the reactor pressure must not exceed 1/4 of the equipment’s design pressure; such high levels are not required during the first startup ； Control the pressure increase rate at 1.0 MPa/h to prevent hydrogen bubbling and hydrogen embrittlement ； Control the heating and pressure increase rates based on the catalyst parameters, before proceeding to the next step ； Emergency pressure relief is an operation carried out in accident conditions; when conducting emergency pressure relief tests, various factors must be taken into account, such as the purity of the circulating hydrogen, the hydrogen reduction temperature of the catalyst (which can be better in the presence of oil), and the temperature rise in the reaction bed. After the test, it is necessary to identify any leaks in the hydrogen system ；
The main consideration is the issue with austenitic materials
Then under what conditions can the pressure be increased at a rate of 1.0 MPa/h? Is it true that when the temperature exceeds 95 degrees, the relationship between temperature and pressure no longer exists? Does that mean we no longer need to worry about hydrogen embrittlement?
The effects of hydrogen embrittlement must be taken into account in hydrogen-containing environments; the hydrogen embrittlement threshold has the greatest impact on equipment and poses the most severe hazards；
Considering the material of the reactor, the catalyst should not be heated and pressurized too quickly at the beginning.
The main consideration is the impact on the equipment due to the catalyst and reactor materials.