Coking in the gasoline selective hydrogenation heat exchanger, and rapid increase in pressure difference in the pre-hydrogenation protection tank
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Dear friends: May I ask how the heat exchange process takes place before gasoline hydrogenation and pre-hydrogenation? After heat exchange, the mixture is heated with steam before entering the pre-hydrogenation reactor; however, the steam heater suffers from severe coking, and it becomes unusable just one month after operation begins~! There is also a protection tank before pre-hydrogenation; the pressure difference in this protection tank rises very rapidly, by 0.01 Mpa per day! May I ask how everyone’s heat exchange process works? Is this kind of situation possible?
Then your raw materials must be really dirty; use an automatic backwash filter
The backwash filter is available; currently, coking occurs after heat exchange, and the coke ends up in the reactor~!
The amount of hydrogen supplied is insufficient; increase the hydrogen supply before pre-reaction
So, how much do you adjust the hydrogen-to-oil ratio in reverse?
Previously, the pre-reduction hydrogen-to-oil ratio specified in our process was not less than 100; now that the process has been modified, a hydrogen-to-oil ratio of 3-5 is sufficient
Oh, we carry out selective hydrogenation; the pre-reaction is the reaction of thiol and diene to form sulfide. Function of removing dienes and thiols. The hydrogen-to-oil ratio is controlled at 7
If it’s this manufacturing process, it still gets dirty
It’s not that the raw materials are dirty; do you have a storage area for preparing materials? If coking occurs, it will happen quickly; it is necessary to switch entirely to direct feeding by the equipment. If the material is supplied directly to the device, what is the steam temperature set for your last steam heater? Is the temperature and pressure reducer not in use? The temperature of the last steam heater should be kept around 250 degrees.
We have intermediate tank areas~! A floating roof tank is used. We’ve also tried direct feeding, and it has a significant impact~! Our heater design reduces the medium-pressure steam to 2.2 Mpa in terms of temperature and pressure. Around 240 degrees – the coking was too severe, so we modified the system to use low-pressure steam; the temperature then was 160 degrees, but coking still occurred heavily. . . .
The intermediate tank area is not suitable; oils containing light oils must be stored in floating roof tanks. These tanks cannot prevent the presence of oxygen, and the problem arises mainly from the oil coming into contact with oxygen. If you turn your head away, you can insist that the problem of supply interruptions won’t occur again.