Should there be a interlock cut-off valve at the outlet of the diesel hydrogenation feed pump?
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Considering that in the event of a power fluctuation and the hydrogen feed pump stops, hydrogen could potentially flow back through the pump into the crude oil buffer tank, resulting in an accident. Although there are check valves and control valves at the pump outlet, the sealing performance must be poor; moreover, with such high pressure, flow will reverse instantly! Should a shut-off valve and a pump interlock be installed at the outlet of the hydrogen feed pump, such that the shut-off valve closes when the pump stops?
Yes, attention has been paid to this issue since the Jiujiang accident, and various related or similar requirements have been added.
The outlet of the feed pump in the hydrogenation unit is equipped with a shut-off valve to prevent backflow in the event of a sudden shutdown, especially under high pressure
We have dual check valves, and we plan to add cut-off valves.
The outlet pressure of the hydrogen feed pump is high; it is advisable to install dual check valves, as well as solenoid valves, along with a low-low interlock. A pneumatic valve is installed before the mixing of crude oil and recycled hydrogen, which is also linked to the low-low interlock. A check valve is installed in front of the pneumatic valve to prevent hydrogen from flowing back. In the event of very low flow rates, in principle, the feed pump, solenoid valve, and pneumatic valve are all turned off simultaneously; functionally speaking, the pneumatic valve responds faster than the solenoid valve.
Some pumps have shut-off valves that are closed to prevent backpressure
In the new design, there will be a low-flow interlock cut-off valve at the outlet of the reaction feed pump, along with two check valves
A shut-off valve is installed at the outlet of the hydrogen feed pump, and two check valves of different types should be placed at the pump outlet. In the case of a new design, it is also advisable to ensure that the safety valve of the inlet buffer tank can handle the discharge volume that occurs in the event of backflow
The last edit to this post was made by Lao Wu Set on 2020-9-21 at 12:00. It’s generally unimaginable that such a problem would occur; immediately shut off the feed control valve via the central control system, so that the unit cannot be started for a short time, and then close another upstream valve as well. For some, the problem still lies in management.
We also installed cut-off valves during the maintenance work here this year