1 reply to this topic

[troske]

Hello,

 

I have been tasked with determining if a compressor can be swapped out for a smaller one at one of my companies gas plants.  I have done a simulation of the plant on VMGSim the gas processing facility.  What we are mainly concerned with is that the refrigeration process has a massive 3-stage Ingersoll-Rand propane compressor and we clearly do not have the throughput (180 e3m3/d, ~10mol% C3+) required to effectively run the compressor.  It mainly just runs on recycle.  The flow rate I determined out of the De-eth tower is similar to what they are seeing out in the field for recoveries (22-24 m3/d LPG).

 

At the plant they have an alternate compressor that could be piped in if it will handle the load.  I have attached the specs I was given on the smaller Mycom compressor which they would like to use as a replacement.  The HP on the driver was guestimated but can be changed out if more power is required, which my simulation suggests.  Im getting a requirement of close to 82 HP.

 

My operating conditions for the propane compressor is:

Ps = 219 kPaa

Pd = 1516 kPaa

Ts = -23 C

Td = 66.6 C

24 e3m3/d

 

Does anyone know anything about this compressor??? Curves, capacities, etc??

Mycom 8WJ-BB, Full Load RPM 1770, Electric drive Type CFR7, 364T frame, 460 Volt, 7.2 AMP

 

THoughts??

 

Also they chiller is running quite hot right now (-16C vs -23C).  Anyone familiar with refrige plant optimization?

 

Thanks,

 

Travis

 

 

[Art Montemayor]

Travis:

 

I am finding it difficult to understand what the problem is and what it is made up of.

 

Instead of thoughts, I am generating questions.  You state you have already simulated the application; can you simply submit a process sketch of the refrigeration system and the corresponding refrigerant composition as well as the temperatures and pressures?  That would much simpler, clearer, and more accurate than having to write about it.  For example:

 

You tell us you want to replace a 3-stage, “massive”, compressor with a Mycom screw compressor.  But you don’t tell us what type of massive compressor you are replacing.  I guess it is an old Ingersoll-Rand reciprocating compressor.  I can’t guess what the compressor is supposed to do.  Is it a conventional refrigeration compressor in a closed, circulating loop of mechanical refrigeration?  Or is it a process compressor taking off gases from a De-Ethylene unit and compressing the gases so that the y can subsequently be condensed into LPG (approximately 50% propane and butane)?

 

You say you don’t have the throughput (180,000 m³/d, ~10 mol% C₃+) required to effectively run the existing compressor.  Does this flow rate represent what is being cooled or is it the re-circulated flow of a closed loop, refrigeration cycle?  Also, you call this compressor a “propane” compressor while the gas you identify as only being 10% propane.  That isn’t propane.  But since you don’t describe the composition of the gas, I can’t tell what it is.

 

Clearly from what you write, you need a smaller compressor.  But you must identify the capacity of the Mycom and its service design first before evaluating it.  In fact, the quickest, most accurate and efficient way to find out if the Mycom will do what you have simulated is to call Mycom and request they evaluation of the application.