What is instrument air system? Industrial instrument air system design consideration?

Introduction to Industrial instrument air system:

Industrial processing installations consist of a broad range of pneumatically operated machinery that requires a pressurised air as motive force for operation.

It is important in an Oil & Gas project is to evaluate the amount of components that require instrument air (IA) and each element’s ability (e.g. control valve) to determine the necessary instrument air system capability.

A typical instrument air system:

The figure below shows the illustration of a typical instrument air system:

Components in an instrument air system:

How Instrument Air system functions?

The primary elements of an instrument air scheme are an inlet air filter for decontaminating the atmospheric air from dust and debris, an air compressor for generating instrument air at the necessary pressure.

A cooler for cooling the warm air from the discharge of the compressor, a separator for removing any condensate from the compressed air, an air receiver for storing compressed air.

A set of molecular sieve air dryers to dry the instrument air to the necessary dew point as a desiccant. Air dryers are operated in cycles where one dryer is operated. The other dryer is regenerated using the pressure swing adsorption (PSA) method to remove water vapor.

Instrument air system design consideration?

Minimize Pressure Fluctuations: Reducing pressure fluctuations is needed. This also means that there must always be adequate pressure at a constant pace for procedures using IA and measured in time units.

Short Term Air Demand:The demand for instrument air (IA) can sometimes fluctuate to a peak in process equipment. This must be taken into account in the estimates of the air compressor ability and in the related storage quantity.

Energy Savings: Instrument Air Systems frequently run power consumption and it becomes imperative to achieve power savings by operating the air compressor (loading / unloading) only as and when necessary