2 replies to this topic

[Herbid]

HI, Introduce me I am a newbie,

and sorry for my english,

I am from Indonesia.

 

My office now working in a Nitrogen Gas Booster.

 

These are the specs from my client.

1. A supply gas is 500 m3/hr

2. A pressure is 3.5 Bar

 

They ask to Increase the pressure gas up to 7 bar.

And my office arrange a system with these equipments:

1. Corken T891. A double-acting machine with piston displacement just over 100 ft3/min (169.9 m3/h).

2. 30 Kw Teco Motor (380 VAC, 3 Phase).

 

A compressor is working around 700 RPM and motor runs 1400 rpm.

 

My question is:

1 A supply or Nitrogen's flow is larger than piston displacement (500 m3/hr vs 170 m3/hr).

is it okay?

2. When I do run testing a Corken with Sinamic VSD, do I have to supply air/gas to inlet compressor?

Or it just can suct air from open space?

3. What is the lowest / limit pressure in inlet - suction line of Corken T891?

SInce the manual says this:

"> Low suction, high discharge pressure switch—
shuts down the unit if inlet or outlet pressures are not
within preset limits."

But not telling at all about the preset limit range allowed.

 

Thx for your attention,

Best regards.

Herbid

[Art Montemayor]

Herbid:

 

Your query implies that you are not familiar or knowledgeable in compressible gas flow.  Your statement regarding the supply nitrogen clearly reveals this because you fail to identify the ACTUAL SUCTION CONDITIONS of the nitrogen supply gas.  Simply stating that a gas supply is 500 m³/hr is not enough.  You must specify the actual (or expected) temperature and pressure of the gas flow.  REMEMBER: this is a compressible fluid - not a liquid.  You need to identify the actual volume of the suction gas at the suction conditions (which are not atmospheric) in order to compare it with the compressor's capacity (which is less than its displacement).  Since this is a non-lube machine, I would expect a volumetric efficiency around 70 to 75% - depending on the compressor ring conditions.  You should obtain the actual expected compressor capacity from Corken when the machine operates at the process conditions specified.  I could calculate a fairly accurate capacity, but it is much easier and more accurate to obtain the capacity from the manufacturer.  That's what you are paying for.

 

Consequently, without your full gas supply specifications nothing can be said as to whether the capacity of the single-stage, non-lube, reciprocating vertical compressor is appropriate or not.

 

You also fail to state that you plan to control the capacity (or vary the compressor rpms) with a variable frequency drive controller.  By your mentioning the Sinamic VSD, I presume that is what you mean.  I don't understand what you mean by "testing" the Corken compressor or the mentioning of "air/gas" supply to the compressor.  Please be clear in your thoughts and questions.  All languages - including English - demand clear thought and accurate expression.

 

Section 1.9 Shutdown/Alarm Devices on page 8 of the Corken Manual states that the shutdown switches are supplied to protect the machine.  Therefore, it is up to you to identify what are the pressure limits of the machine.  You should consult Corken to identify the maximum and minimum pressures your machine and driver can tolerate in your specified process.  Your upstream and downstream process should also determine what you should preset your shutdown switches at in order to protect both upstream and downstream processes.  The Corken manual doesn't go into these details because all applied processes are different.  However, one major fault I have always found with compressor manufacturers is that they are frequently not specific in supplying the mechanical design and pressure limits of compressor cylinders in order to ensure these are not exceeded in positive or negative values.  You should have already generated a compressor Data Sheet that clearly specifies these values as furnished by the proposed supplier.  If you don't have a detailed compressor Data Sheet, that is the first thing you should generate.

[Herbid]

Thx for your explanation.

 

The client said they will supply Nitrogen gas with specs;

1. 500 m3/h

2. 3,5 Bar (around 50 psi)

3. Temp. about 30 - 50 Celsius

 

And they ask the result of the booster and after cooler are:

1. 500 m3/h

2. 7 Bar (around 102 psi)

3. Temp. about 30 - 50 Celsius

 

Hope ths clear.

========

 

About run testing the Corken with VSD.

I just learn how to control the VSD, and want to know how to operate it with DO/DI Control from PLC

The command control is standart, Start, Stop, Quick Stop, Set Ramp Up/Down time, Set RPM Motor Up/Down, read the RPM and motor ampere, Run Status, etc.

 

Since the motor already belted to corken's pulley, so without the supply gas/air in suction line,

can I still running the compressor just with the ambient air in the suction line? (I want to make sure that my command control is correct or not)

 

Hope this clear.

Thx.

Edited by Herbid, 28 July 2016 - 03:15 AM.