7 replies to this topic

[Chem01]

Hi all,
We've a Burkhardt single stage doable acting reciprocating compressor driven by a motor being used for H2 compression from 30 to 39 bar, suc temp=40C.
Speed of compressor 620 rpm, Power consumed 66 KW. Capacity at suction conditions = 1950 m3/hr.
Now we want to use it for N2 compression available at 6 bar for its suction.
What must be looked into to finalize weather or not it can be used for the new service?
How to determine different process conditions for the new gas? by use of Aspen plus?
Regards,

[Art Montemayor]

I have done this before, switching from Hydrogen to Nitrogen service on a reciprocating compressor. I've also done other gas services.

The best thing you can do right away is contact Burkhardt and let me them know the serial number and full identity of the compressor as well as exactly what you are proposing to do. Ask them for the specific information:

the maximum and minimum Allowable working pressure of each cyclinder.the maximum bhp rating on the frame.
the expected inlet and outlet pressures as well as the discharge pressure and bhp required.

Also ask for any limitations based on the application.

[djack77494]

You've heard from our compression expert, so you've gotten the best way forward. With anything as complex as the changes you are considering, you should always involve the equipment manufacturer in the decision making process. There are all sorts of potential pitfalls to doing something of this sort. The manufacturer should be well aware of what needs to be examined in this conversion, and getting him involved greatly increases you chance of success. This includes many things that are thousands of kilometers away from modelling and thermodynamics. They won't say a thing, for example, about loadings on your pistons, but the compressor manufacturer will know if that's a problem.

[Chem01]

Thanks Art Montemayor / djack,
You are right, yesterday i've send email to Burkhardt and mentioned the requirement of change from H2 to N2 with all serial numbers etc. I will provide them specific information of flows etc.
The point is this compressor was part of of a large Ammonia plant which we've relocated from Kemira Netherlands. It was being used there for some specific service and not for Ammonia itself, therfore we decided to keep it in warehouse.
Montmeyer is very right, infact for all the major compressors we've contacted OEM (all being handled by GE now), there engineering studies, modifications / refurbishment is almost complete.
This H2 compressor is now required to circulate N2 in close loop for heating of various reactors of Ammonia plant and thats it.
Burkhardt might give some response to us but again without being paid they will not provide specific information and our management will not be spending money on a spare compressor and other options will be consdiered for heating of reactors (like natural gas etc though not as safe as N2)
Can you both highlight what i can do on my behalf being a process engr? Art Montemayor has done this before and must be well aware of what can be done to experiment this compressor.
Regards,

[Art Montemayor]

Chem01:

Burkhardt, like myself and DJack 77494, like to get paid for honest, engineering work done for the profit and gain of others. I consider this fair and equitable – doesn't your management agree that this is humanely fair? Or do they want free, guaranteed engineering advice and calculations so that they can make additional profit for their sole gain and enjoyment?

Both DJack and I have helped a lot of young engineers on these Forums. But we do that by commenting and critiquing what they propose, calculate, or put forward as safe, accurate, or logical engineering products. We do not generate original engineering work or invention for free - complete with legal liability. We like to help others - and we want to help others. But we can't dedicate our lives to doing someone else's work for them – there are just too many other priorities. Right now, I'm on my way to Tucson, Arizona to spend Christmas with my grandchildren. And my grandchildren certainly will always play a more important role in my life than your penny-pinching management.

There is nothing to experiment regarding your proposal to change the service of the compressor. You simply apply your engineering knowledge and experience to the task and make the appropriate calculations and design to make sure the proposal is within the constraints of the manufacturer. Your management should know this. They should also know that if they don't have the qualified, experienced resources to do the task, then they have to purchase consulting engineering services.

I wish you a very Merry Christmas, but I'm afraid I have no presents for your management.

[Chem01]

Art, your response is a surprise and looks a little harsh, anyways i've responded belowBurkhardt, like myself and DJack 77494, like to get paid for honest, engineering work done for the profit and gain of others. I consider this fair and equitable – doesn't your management agree that this is humanely fair? Or do they want free, guaranteed engineering advice and calculations so that they can make additional profit for their sole gain and enjoyment?

No this is not the case, our company is working with GE, MWKL-UK, S&W UK, Yokogawa, ......many many others all being paid. The project was started at 700 M USD and now it is crossing 1100 M USD and we are trying to economize all technical solutions. As use of subject compressor is one of the various options so others will be considered to keep cost within budget.
Both DJack and I have helped a lot of young engineers on these Forums. But we do that by commenting and critiquing what they propose, calculate, or put forward as safe, accurate, or logical engineering products. We do not generate original engineering work or invention for free - complete with legal liability.

I appreciate your support and that must have been helpful for all. I have 5 years of plant running experience and now i am on technical side for two years, this field has various new aspects for me. That is why i wanted someone to throw some light on how to do it what i mentioned? Very clearly if re-furbishment/overhaul of a compressor is required then OEM is the best party to do that, but being a chemical engineer i believe it is wise to first apply all available knowledge, share problem with others and all this not only to enhance technical skills but to use it for the employer.

We like to help others - and we want to help others. But we can't dedicate our lives to doing someone else's work for them – there are just too many other priorities. Right now, I'm on my way to Tucson, Arizona to spend Christmas with my grandchildren. And my grandchildren certainly will always play a more important role in my life than your penny-pinching management.
I do not understand who said to dedicate lives? There is nothing penny - picnhing, it is to econmize, no project has unlimited money and there are many engineers who use their experties and save a lot before going to licensor or OEM etc. Like in our relocated plant licensor asked to replace 15 CW exchnagers and we saved half of them by just changing number of passes or changing their configuration from series to parallel etc.
There is nothing to experiment regarding your proposal to change the service of the compressor. You simply apply your engineering knowledge and experience to the task and make the appropriate calculations and design to make sure the proposal is within the constraints of the manufacturer. Your management should know this. They should also know that if they don't have the qualified, experienced resources to do the task, then they have to purchase consulting engineering services.

We have 3400 employees inluding all at this very location and most of the engineers are top brain of this field, our company doesnt require consultants, though we have some specialist engineers for furnace etc.

I wish you a very Merry Christmas, but I'm afraid I have no presents for your management.
Merry christmas, i have good respect for all members and wish if they can share their experties and provide some guidline.
Regards,

[djack77494]

Chem01,
I'm not doing a good job of understanding your most recent posting. Though you may have a strong reserve of resources available to you, the ONLY person(s) qualified to rerate a compressor for a completely new service is the original manufacturer (in my opinion). I would think that you can undertake discussions with the manufacturer or his representative at no cost. In these discussions you should explore the feasibility of utilizing the compressor in the new service. You should be able to obtain a pretty good idea about whether or not it would be possible to reuse the compressor and an idea about the nature and cost of any required modifications. This, of course, is subject to the manufacturer being willing to provide this as a free service to you, the customer. He/she might do so with the (implied) understanding that you would utilize their services for these modifications if the project moves forward. They would be doing this as a favor to you, so do not be overly demanding. The whole process would be a bit like asking them for a proposal. They'd probably be willing to invest a small amount of time and resources to do a feasibility analysis for you. If this were a very serious inquiry, they might invest even more. You must put yourself in their shoes remembering that they are doing (perhaps very informally) their own analysis of the risk vs. reward for investing in your problem. If you want more than they will freely supply, open your wallet. Your budget difficulties and the fact that you state payments were made to other suppliers is totally irrelevant to your relationship with Burkhardt. You must have a carrot to offer them. It is not reasonable to expect a free engineering design that would enable you to independently obtain any needed parts or equipment from a third party.

You should note that this is quite different from some of the examples you provided. Heat exchangers, for example, can exchange heat between any conductive fluids. They can also be analyzed with a very high level of success by experienced designers using modern, sophisticated software. They are pretty much "generic" devices, in that I can go to manufacturer A or B and get very similar equipment for a specified service. This is generally not true for compressors.

Your interest in obtaining the maximum value for your employer and your interest in developing economically attractive solutions are commendable. Keep up the good work.

[Chem01]

Thanks djack for the reply,
i agree what you have said,, i can get some initial response from OEM to know what modifications etc are required and then very clearly they'll submit technical / commercial quote which will be finalized on some price basis.This is one way....and it takes some time like its been one week when i contacted Burkhardt, also sent them a reminder but no response yet....hope they'll reply soon.

Djack, i give an example of what i wanted...
We have a Natural gas booster centrifugal compressor whose service is changed from a Natural gas having CH4 contents from 85-90 % to 70 % (rest mainly CO2, N2).
It means for the same production level we require more flow to pass through compressor and by looking at the performance curves we realized the compressor
will run under overload conditions,,very much right to the operating point. So i come to know through performance
curves one of the potential problems of overload and later we went to OEM, in engineering study he also highlighted this problem
and these days compressor is with OEM as its impeller is being trimmed.
Similarly i wanted to know beforehand what can happen to recip compressor? Though detail study
and modification will be by OEM but to foresee today and right now being a qualified and experienced engineer what should be i looking at..?
This is the reason i put up question in this forum...
Regards,