What are the procedures for starting and stopping the new hydrogen compressor (cyclic hydrogen compressor) in the hydrogenation unit, as well as the sequence of operations for the inlet and outlet valves?
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Hello everyone. We are currently drafting operating procedures. Our company operates hydrogenation units, which include new hydrogen compressors, recycle hydrogen compressors, and horizontal symmetrically balanced (DW) piston reciprocating compressors. (1) Air volume adjustment is performed via a load-bearing unloader (0%). 50%, 100%), (2) The new hydrogen compressor has two stages – one with a control valve and bypass, and a second compression stage ； The cyclohydrogen compressor has one suction and one discharge port, with single-stage compression. Question: Regarding start-up and shutdown procedures, I have also consulted many operating guidelines, but the procedures vary from one source to another. There are also differences in opinions within the company, haha. (1) Start-up procedure: Operation at no load – close the inlet and outlet valves, and open the circuit (2-way 1 or 1-way 1); set the unloading valve to 0% ； No-load operation: First open the inlet valve, then open the outlet valve, while closing the circuit valve (the new hydrogen compressor shuts off the circuit bypass, with the control valve used for adjustment) ； Operate under load: Once normal, adjust the unloader to (0%). 50%, 100%). (2) Shutdown procedure: (1) Lower the unloader (100%). 50%, 0%) ； (2) First close the outlet valve, simultaneously open the return valve, and finally close the inlet to shut down the machine. If I follow the steps above, will it work? What are the potential issues? What are the risks? After all, we are doing hydrogenation. Note: The main points of confusion and debate: (1) Should the inlet valve be opened first when starting up, or the outlet valve? (Some operating procedures involve opening the inlet first, or the outlet first; there are also those where both the inlet and outlet are opened.) (2) Shutdown: Should the inlet be closed first or the outlet first, before shutting down the system? (Some stop operating immediately without shutting either the import or export functions, while others shut either the import or export function.) After seeing this many times, I’m confused! I hope experienced friends can offer some advice; I am truly grateful for this! (Can be explored in more depth if possible: QQ490353238)
When starting up, the inlet and outlet must be fully open. With no load, and after all checks have shown normal results, start the machine under no-load conditions; once it is operating properly, introduce a load. When shutting down, first remove the load, then stop the motor, and finally close the inlet and outlet. There are check valves at the compressor outlet, so when the load is reduced to zero, the outlet pressure will not reverse, unless there is a leak in the check valves. This is how our systems are operated
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If both the inlet and outlet valves are open before starting up, there will be fluid in the unit; starting it up with fluid present can cause the check valves in our equipment to leak internally. With both the inlet and outlet valves closed, the unit cannot start without any fluid present – isn’t that a problem?
The suction and exhaust valves are equipped with unloaders that open a bypass when the inlets and outlets are fully open; in this state the compressor operates under no load and does not produce any work. After the compressor is started, the unloader is used to put the compressor under load, while the bypass valve is closed to adjust the pressure at the inlets and outlets. If there is no unloader, then the inlets and outlets must be closed in order to activate the bypass. Once the compressor is running properly, the outlet valve is gradually opened, the bypass is closed, and once the pressure at the outlet increases, the outlet valve is fully opened.
Zero load and closed inlet and outlet valves are two different things; the load is controlled by closing and opening the inlet valve
I’m not familiar with the processes in hydrogenation units, but a compressor is essentially a piston pump; just operate it according to the guidelines for volume pumps. Before starting up, the inlet and outlet valves must be fully open.
Start with no load, with the outlet closed and all circuits open; then slowly open the inlet to start up. Increase the pressure by closing various circuits, and once the outlet pressure is slightly higher than the system pressure, open the outlet. Adjust through the circuits to ensure minimal fluctuations in the gas output, until the outlet is fully open
The new hydrogen compressor is a reciprocating compressor. 1. To start the compressor: Of course, the inlet and outlet valves should be fully open, as well as the two-return-one-regulation valve (it’s best to also keep the bypass line of the regulation valve fully open to ensure stable inlet pressure for the compressor). Set the load regulator to 0, then increase the load control value and reduce the flow in the return line. 2. To shut down the compressor: Keep the inlet and outlet valves fully open, and increase the setting of the two-return-one-regulation valve (determine the appropriate setting by checking the inlet pressure to maintain stable pressure in the new hydrogen pipeline system). Set the load regulator to 0, and then shut down the compressor
When starting up, the inlet and outlet must be fully open; with no load, and after all checks have shown normal results, start the machine under no-load conditions. Once it is operating properly, apply load. When shutting down, first remove the load, stop the motor, and finally close the inlet and outlet