Reciprocating Compressor Discharge Line Check Valves 2

[PseudoMech]

Hi All,

This is my first post on here so apologies if it's maybe in the wrong spot...

I need two "dissimilar" check valves on a line downstream of a reciprocating compressor (i.e. they must be of the non-slam type)

I know my Company has used Hoerbiger valves for this purpose in the past, but for this particular application I need an additional valve which has to be "dissimilar".

Does anybody have any experience/recommendations for other valve manufacturer's/types for this application?

Thanks in advance.

 

[cloa]

Better in the valve engineering forum.

 

[DLite30]

Cameron has a few check nozzle type check valves that can be used for this application.

We've also used swing type check valves with a slam retarder installed on some installations.

 

[JJPellin]

Why do you need two check valves downstream of a reciprocating compressor? We typically consider a check valve unnecessary in this application. The compressor itself is made up of check valves at the inlet and outlet of each stage. In order to have a backflow event, at least one inlet and one outlet check valve would have to fail at the same time. These valves are less likely to fail this way because the failure would not tend to be a hidden failure like you see with a simple check valve in the piping. These valves have to actuate with each stroke of the compressor. And, the failure of any single valve (inlet our outlet) would cause the compressor to stop working. So, individual valve failures are immediately self-evident. The combination of constant opening and closing and the impossibility of a hidden failure make it unlikely that you could have a major back-flow event. I assume your need is driven by some Process Hazard Analysis (PHA) concern. Please correct me if my assumption is wrong.

Johnny Pellin

 

[PseudoMech]

Thanks all for your input.

Johnny, you are right; the requirement came from a HAZOP. However, in our system we have a recycle line and as such are unable to rely on the compressor valves themselves as a means to prevent backflow.

 

[chief]

it is my experience, that without a check valve on the discharge of a reciprocating compressor, the unit will run constantly because of a certain amount of backflow. The integrated leaf type check valves in a compressor are rarely leak proof.
The discharge check valve is normally a positive gas tight seal type.

Offshore Engineering&Design

 

[JJPellin]

We may not be speaking of the same sort of compressors. The compressors I am working with compress hydrogen up to as much as 2000 psi. Industrial machines of this sort use poppet valves of a design that provides tight shut off as good as any in-line check valve.

Our PHA system would still not count two standard check valves as a layer of protection from this sort of HAZOP risk. Any check valve will stay open while flow is present. If that check valve were to stick open, the failure would be hidden. Adding a second check valve does little to reduce real risk.

As an alternative, we would use some other process parameter to detect forward flow. On loss of forward flow, a fast acting chop valve would close to prevent back-flow. This system can be tested, calibrated and monitored. Multiple transmitters (usually two out of three voting) will both assure that it actuates when it should and greatly reduce the chance of false trip of the system. Of course this system would need to be designed such that it allows for proper operation of automatic de-pressurization systems, safety relief valves and other instrumented protection systems.

With all this said, I suspect that this HAZOP action item is probably not negotiable. If the action is already determined and you have no option but to implement it, then my points are academic. Someone else will have to help you understand what technology exists for in-line check valves that can satisfy your requirement. This is not my area of expertise.

You mentioned Hoerbiger valves. I am not an expert on this company. But, we contracted them to rebuild our compressor valves for a period of time many years ago. I don’t think of this as a particular type of valve. In other words, Hoerbiger makes or repairs channel valves, ring valves, poppet valves, etc. If you told them you wanted two valves of different types, I suspect that they could accommodate you.


Johnny Pellin