7 replies to this topic

[AKS1010]

Hi All,

 

In one of my Revamp Job there is a HP Steam Turbine and LP Steam Turbine driving a single Centrifugal Compressor. We need to modify only HP Steam Turbien. I just want to know the reason behind using two turbines for drivinga single Centrifugal Machine. 

 

Please share ypur knowledge or if you need any other information do let me know.

 

Thanks in advance.

AKS

[mahmoud bedewy]

Please let us know more info about both compressor & Hp steam turbine like inlet & outlet press. Rpm of turbine etc.
Hope i can help as we have a system like that

[PingPong]

It seems to me that that was an economical decission.

 

If there was an excess of LP steam at that time, it was considered advantageous to use that to drive the compressor so as to save HP steam.

[AKS1010]

Ping Pong,

 

Its a 3 stage Centrifugal Machine in Process Service compressing gas from 24 kg/cm2G to 145 kg/cm2G. 

 

HP Steam Inlet Pressure is 100.67 kg/cm2G @ 454 Deg C, Extraction is at 39.7 kg/cm2G. Exhaust of Condensing Turbine i.e LP Steam Turbine is 117 mmHgA.

 

HP Steam Inlet Flow is 285764 kg/hr and Extraction Flow is 267330.5 kg/hr.  

[PingPong]

So there are not really two turbines, but one turbine consisting of two parts, with extraction of steam in between.

 

It is the steam balance of the whole complex that determined the original design choice, just as it is the present steam balance of the whole complex that determines how much steam is now extracted. Equipment limits also have an impact of course, because reducing the extraction too much would result in overload of the condensor.

[mahmoud bedewy]

Due to the very high press. Of. Suction and discharge of compressor, and also Hp steam we can not wast the power of low press. Steam.. 267330 kg/hr steam @40kg/cm2. CAN NOT BE WASTED
but i have a question, how could a 3 stage CENTRIFUGAL comp. Handle that huge press. Delta P =121kg/cm2,am i confused?

[PingPong]

What matters is pressure ratio, not pressure difference. Ratio is only 6 which is no problem for a 3-stage centrifugal machine.

In fact, a 2-stage machine could probably also do the job.

[himant]

well.. how about control system to control the turbine load?

 

I have never seen such turbine.. does it has two governers?

 

can you please share the details of this turbine?