Quickie, work-related.

Hydrocarbon gas compressor, running at ~17000rpm, bearing temps of ~70-100°C, seal oil flash point varying between 70-95°C, seal oil holding tank temp hovering around 80°C with excursions as high as 105°C.

Cause for concern?

I would say yes but surely a flash point is a flash point not a variable?

Varying process conditions, flash points affected by a number of factors, biggest fluctuations come with changing pressure differential across the compressor.

Seal oil drains simply do not work, I assume they’re blocked, so all sour oil is returning to the holding/supply tank.

I’m no rotating equipment specialist, which is why I’m asking. Getting zero support at work and it seems I’m one of only a very small handful who sees the potential risks associated continued operation.

Is the thought that the lack of o2 makes it not a risk?

Worth a read

http://www.oceanteam.eu/images/Articles/PDF/1_Turbine_Compressor_Ocean_Team_.pdf

There is an inert gas (N2) blanket on the tank, yes. I have no idea what the thoughts are though because nobody appears to care enough to explain why we’re still running the compressors, in breach of company operating procedures I might add.

The bearing temps are not necessarily the same as the oil temps though. As falkirk-mark suggests, flash points are calculated at certain conditions so it may not be a huge risk. Can you throttle the compressor frequency back and still hit the head?
If the oil is burning, then things are clearly not good. It should not be “sour” and I’d be asking some pretty ****ing pointed questions at the maintainers if that is the case (not to mention the blocked drains)

From a teflon viewpoint, an email to your line manager and SHE manager should cover you and likely prompt a response.

Can you throttle the compressor frequency back

It’s centrifugal rather than reciprocating. Compressor is fixed speed, or at least we give it a certain suction pressure and it gives us a certain discharge pressure and it’s always at around 17000rpm under those conditions. I don’t have any reason (from a job role perspective) to know what happens “under the hood”, so can’t answer much more than that.

From a teflon viewpoint, an email to your line manager and SHE manager should cover you and likely prompt a response.

Ha. You’re kidding, right? More like a “just stop moaning and do your **** job” response. As in, that’s the response I’ve already had.

You can vary the speed of centrifs as easy as recips. Variable speed drives are so common now, they are aren’t so much used for the variable bit as much as negating the need for (expensive) star delta/DOL.
I suppose that if your oil is ***ked, then your compressor temps are going to be ***ked.
If you’re controlling the suction, can you ease it off a little and still get workable discharge, with a view to lowering the run temps?
If out of parameters, even a centrif compressor may eat itself before the oil hits FP.

What risk does the seal oil present that does not already exist by virtue of the presence of the gas? The gas is flammable and warrants a nitrogen blanket, so what extra or new risk will flammable vapours from the seal oil introduce?

You have a system where flammable gas/vapour and a potential ignition source (the compressor) are continuously present, so your focus has to be on the reliability of the controls to prevent the escape of gas from the system and the ingress of oxygen into the system (incl. failure of the nitrogen blanket).

If company procedures prohibit such a set up, then can you check with whoever is responsible for those procedures as to why, and what the company would expect to be in place instead?

The gas is flammable and warrants a nitrogen blanket

The gas is supposed to be kept within the pipe and so hazards from that are, in theory, at a minimum. The seal oil prevents process gas escaping to atmosphere. Oil in contact with gas should pass through drains in the compressor to a separate contaminated oil package. This is one of the major controls in place to minimise risk of gas release and it has failed: the drains appear to be blocked so the contaminated oil has nowhere else to go other than back to the supply tank. This oil is saturated with gas and this is what warrants the nitrogen blanket, not the gas itself. If everything worked as it should there would be minimal risk from the gas. Historically the oil flash point was around 175°C but ever since a compressor strip and rebuild they’ve been less than 100°C.

The most annoying thing is deviation from procedure is considered, in most cases, gross misconduct and grounds for dismissal, and I know people who have been fired for not following procedure. It is drilled into us from day one about the importance of following procedure.

But it’s OK to ignore procedure if doing so either makes money or prevents expense, or so it seems.

The procedures are there for a reason, the “action limits” are there for a reason, and they explicitly state that any flash points under 100°C require an immediate compressor shut down. I could maybe understand if someone within the company could provide us with a reason why we’re OK to keep on as we are, and we’ve asked repeatedly over the last few months, but the lack of response speaks volumes. As do the implied threats about our continued employment with the company.

It’s getting to the point where I may end up losing my job for either refusing to “follow orders” or taking matters in to my own hands and hitting the stop button. I’m fully prepared for this and I’ll accept it if it comes. I just want to make sure I’m not making a stand for the wrong reasons.

I’m a process safety engineer by qualification, although not really part of it anymore.

I’d file that under ‘marginal’ in terms of temps, and be pointing this out in writing.

Also, by sour, you mean oil contaminated with process fluid, yeah? I’d be concerned that the marginal temps you’ve got have lead to the seals being improperly lubricated/sealed and drastically reduced their MTtF

+1000 on an arse covering email.

sobriety you sound like just the person we need.

Yes, seal integrity is one of my concerns. I mean sour oil as in oil contaminated with hydrocarbon gas from the process. What would you say the short, medium and long term hazards are in this situation? Bearing in mind this has been ongoing since January this year, maybe longer. 4 x compressors in sequence taking gas from ~1.5 barg to ~140 barg from start to finish, all with the same issues.

O+great valve man here so while I can advise on a fair bit the compressors are a different matter.

I’d suggest that in these climates I would be wary about giving people a reason to put a mark against you. However I would definitely be putting it in writing to your line manager and a few others asking for specific advice if any action should be taken.
It’s easy for people to dismiss stuff like this till it goes tits up then it’s a finger pointing exercise.

Fuuuuuuuuck.

Full seal failure on the final stage leading to a release of hydrocarbon to the drain system would be my worry, the pressure will shift whatever is blocking the drain, and if it doesn’t where will the HC go?

Assuming it’s flammable, then the next assumption you make is that it will find a source of ignition. So you’ve at least got a fire on your hands, and potentially an explosion.

I’d be letting the HSE know and seeing what they think. You’ll probably end up having to leave, as making your bosses look like dicks and possibly getting them hit with a fine won’t go down well. But if you do nothing and it all goes bang while an operator is stood next to it, how would that make you feel?

Hopefully Thisisnotaspoon will be along shortly to confirm if I’m overreacting or not, for he is at least as qualified as I am to spout off on this subject.

We’ve got a similar issue with one of our compressors, but have risk assessed its continued operation with some additional control measures in place.

You could always contact the HSE anonymously and raise a concern.
No need to lose your job and the issue gets dealt with.

Assuming you’re in the UK, of course.

Cheers sobriety. Seal failure seems plausible, given the complete lack of appetite to do anything about the issues.

rugbydick – what control measures have you got in place? Ours are currently pretending the issue doesn’t exist. One of the supervisors has even denied there’s an issue when onshore specialists have asked.

A few thoughts:

– Clearly you in the middle of a classic safety vs. continued production scenario. Evidently senior management are avoiding the issue, and by their omission/inaction seeking to make you responsible for the decision to continue or stop. In that sort of situation I would consider a detailed email/report to the site director/manager, summarising the issues, including pointing out the risks and consequences (not just the consequences in terms of plant damage and downtime in the event of a fire/explosion, but also the potential for fatalities if applicable, and also the consequences for the company and individual senior managers (i.e. them), e.g. prosecution resulting in fines and prison sentences). Mark the email to send you a receipt when opened/read, and print off hard copies of all previous and future emails and keep them in a safe place.

– If UK based, who has undertaken the DSEAR assessment? If it’s not you, then I would ask for the assessment to be reviewed/updated by the person who did it or is now responsible for it. The changes you describe (drains not working, flashpoint raised etc.) would almost certainly be classed as ‘significant’ and therefore trigger a requirement for the DSEAR assessment to be reviewed.

– Is there no internal company safety audit process? If this state of affairs has existed for months, then it’s the sort of thing that a good safety audit should pick up and trigger immediate negative feedback for the site and site manager. The fact that senior management are not responding to your communications suggests that they are not worried about the consequences for them of this being picked up on an audit.

large organisation, or sub-contracting for one?
whistle-blower program?

Quickie, work-related.

Hydrocarbon gas compressor, running at ~17000rpm, bearing temps of ~70-100°C, seal oil flash point varying between 70-95°C, seal oil holding tank temp hovering around 80°C with excursions as high as 105°C.

Cause for concern?

I’d raise this and ensure that the correct risk assessments have been done.

Flash point is a specific test. You might be ok. I do have done a fair bit of flash point testing on paint in my career. There are loads of methods. The one i’m familiar with involves heating a small sample in air to the req. temperature then using a small pilot flame to see if it ignites.

Key to this is the fact you need air and an ignition source. There is no issue with heating something above the flash point if there is no ignition source (or air in most cases).

A good example would be toluene, flash point is 6degC but it is widely used in temperatures above this in quantity. The controls need to be in place though. Air changes, earthing and use of Atex rated equipment to reduce the chances of enough material finding a spark to cause and explosion.

A further thought:

– In addition to regular safety audits, there should also be a site wide system for recording and tracking health, safety and environmental deviations/non-compliance and the progress towards corrective action to close them out, e.g. on a spreadsheet or similar. The spreadsheet should be regularly reviewed by the site senior management to monitor progress, and it should be also be sent to the relevant managers responsible at corporate level for group safety management, who should be using that information from all group sites to monitor the group’s overall safety performance, and be regularly updating the board with that information.

In other words, it should not be the case that you are having to keep chasing your line management for a response and instructions: they should be the ones chasing you because the deviation should be a red flag trigger prompting pressure on them from the site manager and from corporate to explain why it has not been fixed and when it will be fixed. Again, it sounds like there is no such system in place, or if there is then it has broken down, which is very concerning given the obviously high hazard nature of your processes/industry.

All 4 units have same issues? Does this mean the drains are blocked on all 4?

There will / should be be an automated unit shutdown process in the event of seal failure, unless they been overridden in order to maintain production.

In your case IMO the severity potential of personnel injury is much the same as prior assuming all the safety systems for unit / area are intact and functional, as the potential for full seal failure would / should have been considered during the design phase i.e. auto shutdown & blow down initiated, F&G detectors in the area etc. It’s just that the likelihood of this scenario happening has increased somewhat.

More concerning to me would be the attitude you say has been displayed by the management of the platform towards this situation, if they are sanctioning this deviation from procedure for the sake of production without following risk assessment/ MOC procedures then not a place I would want to work.

Unfortunately this attitude seems to becoming more prevalent throughout the North Sea in the current economic environment despite the public face of companies ‘commitment to safety’

Where I work we are ‘starting to utilize the full potential of our risk assessment procedures’ to optimize production in cases similar to this, but at least appears to be a step on from your situation.

There is no issue with heating something above the flash point if there is no ignition source (or air in most cases).

The issue here is that a lowering of the oil’s flash point is indicative of a problem with the compressor seals; i.e. hydrocarbon gas is leaking out of the compressor.

@The Flying Ox – probably can’t go into specific controls here as our compressors use an inert dry gas seal and the oil is only lube oil; we don’t have any issues with vents or drains. Things to look at would be making sure that any vibration monitoring and gas detection on the compressor is operational, with full ESD functionality. Setting an absolute lower limit for the oil’s flash point with regular testing. That sort of thing…

Cheers for the advice folks. Email outlining our concerns and documenting the almost continuous deviation from procedure will be sent tonight.

Good luck with the email. I suspect you may be pretty angry and frustrated that your previous communications have been ignored, and that you have been left out on a limb, but try not to let that come through in your email: just keep it factual and dispassionate. Don’t over-egg it or lay it on too thick, but try to couch whay you say in terms that indicate you are acting to protect the company’s interests (assets, revenue generation, reputation and legal, e.g. not only possible H&S enforcement action, but maybe even loss of licence?) and also your email receipient’s interest: in the event of a major accident, it will be no defence for them to claim ignorance, and they will be just as much in the firing line as you if not more so. Phrases like ‘we are extremely exposed if there is an accident’ may be appropriate (we = you want him/her to identify with you and be on your side).

If you can get the site director on your side, he/she may even be able to force an answer from whoever is responsible for the safety rule about why that particular flashpoint threshold was chosen, and if you had sufficient information about the risks, the company (not just you) might be able to come up with a temporary MoC procedure which will allow continued production with an acceptable level of safety pending a permanent fix.