Recycle gas comp. driven source change from HP to electric

[1906]

Recently we are thinking changing recycle gas compressor driven source from HP steam(Pressure 40 Kg/cm2, 400'c) to eletric power in our hydrocracker unit considering refinery steam balance. Re this matter, would you guys please comment on the followings.

a) Merits and demerits of steam driven comp. vs.
electric driven comp.
b) Any experience of eletric driven recycle gas comp.
in high pressure such as hydrocracker.
c) Reliability of each driven comp.
d) Steam driven comp seems to be designed generally
,inform me the reason why, if any.

 

[TBP]

These choices are typically driven by economics. What's the electic power vs steam cost in your plant? Do you have enough capacity in your power system to add this drive, without getting into upgrading substations, etc? Does the steam from the turbine exhaust to a lower pressure system? If it does, then you can have a scenario where the turbine is replacing a PRV station. This means that the turbine essentially runs for free. The flip side to that is, first cost of the turbine, and is there enough requirement for the lower pressure exhaust steam? There are lots of plant and application specific considerations.

 

[zdas04]

TPB got it right. If you have enough steam to run the compressor and you don't have a substitute load then replacing the turbine with electric-drive adds a brand new cost stream without removing the old one.

The compressed gas won't care if the compressor was driven by a competently-designed steam turbine or a competently-designed motor. I'd have to have a really compelling reason to invest the capital and bear the operating cost of the change over.

David

 

[rmw]

You need to tell us what the phrase "considering refinery steam balance" means. The answer lies in knowing what that entails.

rmw

 

[1906]

Re the comment from "rmw" & "zdas04", let me re-phrase in detail about "considering refinery steam balance".

Recently, our company is considering co-generation capacity increase in our turbo-generator operated around 60 ~ 70% of its design capacity usually, by minimizing low efficiency steam turbine usage. With this way we can save purchased electric power cost from national power generation company which is somewhat normally expensive.
Also, we can increase critical power capacity. Thses are the considerations of our refinery.

Again, is there any experience of electric motor for recycle gas comp. in hydrocracking units ? Is IT POSSIBLE TO CONTROL FLOWRATE ? Hope an answer.