Regarding the installation location of the pressure relief valve in the hydrogenation unit
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By observing several hydrogenation units, it can be seen that the pressure relief valves are installed at relatively high positions, generally on the top layer of the platform or on the air-cooling platform. What are the purposes of doing this?
The cold high-pressure line is already at a high level, above the flare line. The main flare line is located in the pipe tray, and the pipe that leads from the safety valve to the flare is at a height higher than the flare line. If you take a close look, you’ll see that it’s generally the case this way, ensuring that gas or liquid can flow smoothly to the downstream path once it starts to flow. If the downstream pipeline is below the flare line, then, if there is liquid inside the flare line, you understand what will happen~~~~
The cold high-pressure unit is a horizontal container located on the ground; it has three platforms on top of it. The outlet pipe leading to the pressure relief valve is connected to the high-pressure flare line, and they are all at roughly the same level
Even so, the pressure relief pipeline connection is inserted above the flare line
Take a look at your design drawings or construction plans – there are strict requirements regarding all the vent pipelines for the flares. The main vent pipeline is not at the same level; rather, the end of the main pipeline is at a higher height, while the horizontal pipe at the inlet of the flare separator tank is at the lowest height. This slope is intended to prevent the liquid contained within the pipelines from flowing back into the separator tank after the safety valves activate and pressure release stops, thus avoiding the accumulation of liquid in the pipelines and potential surge problems during subsequent pressure releases. The outlet pipelines of each safety valve must be at a higher height than the main pipeline, and the pipeline design also ensures that the outlet of the safety valves is at a higher level and the inlet of the main pipeline is at a lower level. In some designs, if there is no liquid present, the safety valve branch lines can be located below the main pipeline (as is the case with various vent collection branches in the hydrogen compressor plant area of many installations). However, the main pipelines (the safety vent collection lines between different levels) also need to have a certain slope, and a liquid separation tank is installed at the lowest point to prevent liquid from accumulating in the pipelines.