4 replies to this topic

[empower70]

One of the tyre industry is having compressed air requirement(sr. no. 1,2,3)and instrument air requirement(sr. no. 4,5), as per attached sheet no. 1.
The pointwise consumption is also given in attached sheet no. 2.
The load pattern is varying, as this is batch plant.
My question is how to size compressor, air receiver etc and how to control outlet pressure.
Is it reliable to use oil injected screw compressor in instrument air compressor.


One of the tyre industry is having compressed air requirement (sr. no. 1,2,3) and instrument air requirement (sr. no. 4,5), as per attached sheet no. 1. (this sentence doesn’t make sense…)

The point wise consumption is also given in attached sheet no. 2.

The specified load pattern varies, as this is batch plant. My questions are:

1) How do we size the required compressors, air receiver etc and how do we control outlet pressure?

2) Is an oil-flooded, screw compressor type acceptable as an instrument air compressor?

Attached Files

•  Compressed_air_requirement___consumption.xls   49.5KB   423 downloads
•  Compressed_air_requirement___consumption.xls   49.5KB   188 downloads

[Art Montemayor]

You double-posted the same topic in the same Forum. I deleted the other post since it didn’t have any attachments as indicated.

I have also edited your post (as indicated) so it is readable and understandable.

The two workbooks you have attached seem to be the same, yet you state you are attaching two sheets. What do you mean?

Are you an engineer assigned to specify the required air compressor(s) for local procurement? How many compressors do you require or desire? Are you going to have an on-line spare compressor available? Are the compressors to be electric motor driven? What make and model of compressors are you considering?

You cite different compressed air services: Process air, Plant air, High Pressure air, and Instrument air. Do you intend to employ one (or several) compressor to furnish all the air requirements in one operation and subdivide the various applications subsequently by using pressure regulators? Please be specific and detailed in your description. Plant air systems can be designed, organized, and instrumented in a variety of ways. Generate and supply us with a detailed Piping and Instrumentation Diagram (P&ID).

What do you mean by “CFM”? Please be specific in all details. Is this air flow rate measured at actual conditions (if so, what are these conditions?)? Or do you mean “Standard” air conditions? If so, what are the Standard condtions?

Await a specific, engineering description.

[empower70]

You double-posted the same topic in the same Forum. I deleted the other post since it didn’t have any attachments as indicated.

I have also edited your post (as indicated) so it is readable and understandable.

The two workbooks you have attached seem to be the same, yet you state you are attaching two sheets. What do you mean?

Are you an engineer assigned to specify the required air compressor(s) for local procurement? Yes.
How many compressors do you require or desire? Are you going to have an on-line spare compressor available? Are the compressors to be electric motor driven? yes.What make and model of compressors are you considering?Make Atlas copco/Kaiser/IR.Models to be decided once, philosophy is final.
You cite different compressed air services: Process air, Plant air, High Pressure air, and Instrument air. Do you intend to employ one (or several) compressor to furnish all the air requirements in one operation and subdivide the various applications subsequently by using pressure regulators?We have sized as per attached excel sheet.Pls. let me know, whether it can work?How to select no. of dryer/receiver(individual or common) Please be specific and detailed in your description. Plant air systems can be designed, organized, and instrumented in a variety of ways. Generate and supply us with a detailed Piping and Instrumentation Diagram (P&ID).Here we need help, on type of controls.
What do you mean by “CFM”? Please be specific in all details. Is this air flow rate measured at actual conditions (if so, what are these conditions?)? Yes, at discharge condition with 40 deg. C. ambient temperature. Or do you mean “Standard” air conditions? If so, what are the Standard condtions?

Await a specific, engineering description.

Thanks for your elaboarting.

Attached Files

•  air.xls   13.5KB   277 downloads

[Art Montemayor]

Empower:

First, allow me to explain how we can be of help – accurately, efficiently, and safely:

You MUST be specific in supplying us with all the basic data and scope of work you have in your possession. We can only help if you answer ALL our questions. If we have questions, it isn’t because we are “elaborating”. We are asking questions because you are starving us of basic data while we are trying to be of help. You cannot be selective in what questions you answer or don’t answer. If you don’t feed us data, we can’t be of help - and I personally know I have all the answers you are seeking because I’ve done what you propose many times in the past.

We can’t be guessing at what you mean. We either don’t have the time or can’t take the risk of giving you the wrong advice that could be mis-interpreted and miss-used by you. For example, what does your recent spread sheet mean? We can’t be guessing whether you have broken down your air uses or are telling us something else. What are “carbon handling system” and “Nitrogen System” are these also air requirements? Or are you using Nitrogen as an air substitute? We don’t know.

What are the terms “3 nos” and “2 nos”? Again, be specific. Realize that no one here has probably any idea of what your job assignment is or what your facilities are like. It is your job to make sure that we have a full, accurate, and detailed description of what is in front of you as a problem.

I asked you: "What do you mean by “CFM”? Please be specific in all details. Is this air flow rate measured at actual conditions (if so, what are these conditions?)?"
You answered: “Yes, at discharge condition with 40 deg. C”. If you are a professional engineer, then you know your response is flawed and lacking in description. No one can identify what you have described because you failed to state ALL the conditions. You left out the PRESSURE of the discharge – so how can we estimate the quantity of air flow handled by the compressors?

Be reasonable and help us help you.

[empower70]

Empower:

First, allow me to explain how we can be of help – accurately, efficiently, and safely:

You MUST be specific in supplying us with all the basic data and scope of work you have in your possession. We can only help if you answer ALL our questions. If we have questions, it isn’t because we are “elaborating”. We are asking questions because you are starving us of basic data while we are trying to be of help. You cannot be selective in what questions you answer or don’t answer. If you don’t feed us data, we can’t be of help - and I personally know I have all the answers you are seeking because I’ve done what you propose many times in the past.

We can’t be guessing at what you mean. We either don’t have the time or can’t take the risk of giving you the wrong advice that could be mis-interpreted and miss-used by you. For example, what does your recent spread sheet mean?This is preliminary selection of compressors numbers, types and capacity We can’t be guessing whether you have broken down your air uses or are telling us something else. What are “carbon handling system” and “Nitrogen System” are these also air requirements?These are name of units(end users). Or are you using Nitrogen as an air substitute? No. Compressed air will be fed to nitrogen generation system for generating nitrogen, as nitrogen generating system(PSA type) requires high pressure air to generate nitrogen. We don’t know.

What are the terms “3 nos” and “2 nos”? They denotes number of equipments. Again, be specific. Realize that no one here has probably any idea of what your job assignment is or what your facilities are like. It is your job to make sure that we have a full, accurate, and detailed description of what is in front of you as a problem.

I asked you: "What do you mean by “CFM”? Please be specific in all details. Is this air flow rate measured at actual conditions (if so, what are these conditions?)?"
You answered: “Yes, at discharge condition with 40 deg. C”. If you are a professional engineer, then you know your response is flawed and lacking in description. No one can identify what you have described because you failed to state ALL the conditions. You left out the PRESSURE of the discharge – so how can we estimate the quantity of air flow handled by the compressors?I agree with u. I have not mentioned discharge pressure, because it is mentioned in my all excel sheet.

Be reasonable and help us help you.

I hope,have understood your requirements and tried to furnish all information.
Pls. let me know, if any more details are needed.
Thanks Art Montemayor once again for your clarifications.

Regards,

empower