air receiver tanks cap. & compressor FAD

[lalit4bearings]

We are installing a dry fog dust supression system at stock transfer point of blast furnace in a large steel plant.For this we have selected a compressor having FAD 882 cfm at 7 bar.This air will be sent to air receiver tanks.this air will be sent to 2 locations at levels from -5m to 25m.There are 387 nozzles,127 operating at location 1 and rest are at location 2.Nozzle air discharge pr.is 3.5 bar.
On these data we have designed the system with 3 air recrs with delery pr of 7.5 bar.one main recr. is of 5 cu.m. cap. and 2 others of cap.2.5 & 1.2 cu.m. respectively installed at the locations.

The client now says that these cap.are not enough and we should consider 1/6 of FAD instead of 1/10 of FAD as per indian standard IS:7938.Now we are in a fix as we have already placed order and have very little time to finish the project.

I want to know whether the client is right in demand or we should go ahead as per our plan.

 

[chief]

Rule of thumb for air reservoir capacity. Reservoir capacity in Gallons equals compressor flow rate in CFM.( working pressure 7-8 bars). Your reservoir capacity is dependent on your primary vessel size, on which subsequent reservoirs are dependent.
Fit a bypass on your first reservoir, so that you are in effect bringing the other reservoirs into a parallel configuration.
Fit a check valve at the air inlet of all reservoirs, so a demand on one does not affect the others.

Offshore Engineering&Design

 

[quark]

It is 1/10 th of flowrate in cu.mtr/min to 1/6th. So, 1/6th of 25cu.mtr/min is 4.16 cu.mtr. Where is the issue?

 

[chief]

The issue is the the 2.5 & 1.2 M3 reservoirs. Which are fed from the large reservoir.In effect a series system. Converting to a parallel system gives each of the reservoirs the benefit of the full compressor flow rating at any one time.

Offshore Engineering&Design

 

[chicopee]

Regardless of the 1/6th or 1/10th FAD, what is the real purpose of an air receiver? Surely not to supply the air but to maintain an uninterrupted constant supply of air. I am assuming that we are dealing with reciprocal compressors.