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Free Air Delivery(FAD) Metering for Scaling Control Application : Week 3/1/2012

In the last article, we discussed about how can we measure the accurate FAD at the discharge point of the compressor with on-line pressure & temperature compensation. In this article, we will see whether it is possible to both measure & improve the FAD.

The measurement:

With the FAD meter, we have already seen, one can get accurate measurement of operating, standard volumetric and mass flow of conductive and non-conductive liquids, gases and vapors even with fluctuating pressures and temperatures. This FAD meter can be put downstream of your compressor and you will know at every moment, exactly how much air is reaching your process.

The control:

For higher capacities and higher pressure applications, multistage compressors are a more energy efficient choice. In such cases, the inter cooler plays a key role to enhance the efficiency of multistage compressors. These inter coolers are usually water cooled heat exchangers. Any scaling in the inter cooler pipes would lead to loss of efficiency, and thereby increase in fuel consumption by up to 50% !

Please refer Fig. 1 & Fig. 2 below to understand how inter cooler helps to enhance compressor efficiency.

Improving efficiency of Multistage Water Cooled Compressors

Any scaling (caused by water) in the inter cooler would lead to reduction in compressor efficiency. To avoid this, one can install Scale removal technology on the cooling water inlet line to compressor. The Scale removal technology removes existing scales, and prevents new scale accumulation as explained in our earlier articles on Scale removal. There is no need to use water softening chemicals.

This helps to improve and maintain compressor efficiency without shut down maintenance, in a most eco friendly manner. Fig.3 shows the typical installation scale removal technology on inter cooler side of a Multistage Compressor

The improved compressor efficiency due to online descaling of inter cooler pipes can be measured through:

  • Increase in Free Air Delivery (FAD)
  • Reduced KW consumption of compressor motor/ Turbine
  • Reduced loading unloading of compressor

This brings an end to our article series on compressors & FAD measurement/improvement. In our next article, we will discuss about level measurement.