Grasso SP2 two-stage ammonia screw compressor package.

[Jacek]

Hello guys!

I have a question regarding Grasso SP2 two-stage ammonia screw compressor package - could someone tell me about advantages and disadvantages of it in comparison with systems with booster compressors?

For these guys who do not know what Grasso SP2 package is - this machine consists of two independent screw compressors (one for first stage and one for the second stage) with two electric motors mounted on a common frame with a common oil system (a common oil separator).

Thanks for any ideas.

Regards.

Jacek

[RANGER1]

Jacek ,
System you have or refer to has a booster compressor ie first stage .
What i think you are refering to is seperate 2 stage system with intercooler .
Cant see much benefit for Grasso SP2 unless you are wanting very low tempreture system of say below -45 deg C .
Mycom programe shows same performance for single stage economized 200L as 2016LSC compound screw ( Which is basically same as grasso screw but bolted together using 1 elec motor ) .
Conditions of -33 deg C SST / + 35 deg C SCT .

Grasso advantage


No intercooler required
Less components in system ( cheaper installation ) .
Side load into interstage as well as economizer for subcooling

Disadvantage ( compared to single stage economized ) .

2 elec motors to maintain as well as electricals
2 shaft seals to leak
2 compressors to overhaul
Harder to incorporate redundancy in case of breakdown .
Probably only suited to very low temp application , otherwise why not single stage / economize plant ?
If first stage comp is damaged any debris will go into second stage compressor


Maybe you could give a bit more info as to conditions and application

[Jacek]

Jacek ,
System you have or refer to has a booster compressor ie first stage .
What i think you are refering to is seperate 2 stage system with intercooler .
Cant see much benefit for Grasso SP2 unless you are wanting very low tempreture system of say below -45 deg C .
Mycom programe shows same performance for single stage economized 200L as 2016LSC compound screw ( Which is basically same as grasso screw but bolted together using 1 elec motor ) .
Conditions of -33 deg C SST / + 35 deg C SCT .

Grasso advantage


No intercooler required
Less components in system ( cheaper installation ) .
Side load into interstage as well as economizer for subcooling

Disadvantage ( compared to single stage economized ) .

2 elec motors to maintain as well as electricals
2 shaft seals to leak
2 compressors to overhaul
Harder to incorporate redundancy in case of breakdown .
Probably only suited to very low temp application , otherwise why not single stage / economize plant ?
If first stage comp is damaged any debris will go into second stage compressor


Maybe you could give a bit more info as to conditions and application

Hello Ranger1.

Many thanks for your reply.

Telling about comparison, I had the difference between Grasso SP2 machine (or Mycom) and the plant with, let's say, two compressors (one high-stage and one low-stage - a booster compressor) in mind... I'm not talking about the one-stage compressor with the economizer port.

Could you possibly provide me with the brief comparison?

I hope I express my thoughts in a clear way.

Thanks one more time.

Jacek