Chemical & Process Technology: Adjusted Method For Compressor Settle Out (with Vapor & Liquid) Using HYSYS

Tuesday, November 11, 2008

Adjusted Method For Compressor Settle Out (with Vapor & Liquid) Using HYSYS

Display problem ? Click HERE

Since the release of "Simple Method For Compressor Settle Out Using HYSYS", some readers of Chemical & Process Technology raised a question. The proposed method has considered all in VAPOR, how shall this method apply in case of present of VAPOR and LIQUID in Compressor Suction drum and Air Cooler Downstream ?

It is correct that the simple method is simplified version for VAPOR only Settle out condition. Nevertheless, minimum adjustment to the method enable the method to be used for condition with VAPOR and LIQUID. First refer to following image.

Step 1 : Compressor Suction. Estimate physical volume of vapor (Vv1) and liquid (Vl1).

Step 2a : Compressor Suction. Separate Compressor Suction Inlet (stream 1) with 2-phases (vapor & Liquid) with Separator unit operation.

Step 2b : Copy Compressor Suction Inlet Vapor (stream 2) condition and composition to a new stream Actual Compressor Suction Inlet Vapor ((stream 4). Adjust Mass flow of this stream until the Actual Volumetric Flow equal to Vv1.

Step 2c : Copy Compressor Suction Inlet Liquid (stream 3) condition and composition to a new stream Actual Compressor Suction Inlet Liquid (stream 5). Adjust Mass flow of this stream until the Actual Volumetric Flow equal to Vl1.

Step 2d : Mix Actual Compressor Suction Inlet Vapor (stream 4) and Actual Compressor Suction Inlet Liquid (stream 5) to form Compressor Suction (stream 6).

Normally the Compressor Discharge stream is superheated and no liquid is expected.

Step 3 : Air Cooler Downstream. Estimate physical volume of vapor (Vv3) and liquid (Vl3).

Step 4a : Air Cooler Downstream. Separate Air Cooler Downstream Outlet (stream 7) with 2-phases (vapor & Liquid) with Separator unit operation.

Step 4b : Copy Air Cooler Downstream Outlet Vapor (stream 8) condition and composition to a new stream Actual Air Cooler Downstream Outlet Vapor (stream 9) . Adjust Mass flow of this stream until the Actual Volumetric Flow equal to Vv3.

Step 4c : Copy Air Cooler Downstream Outlet Liquid (stream 10) condition and composition to a new stream Actual Air Cooler Downstream Outlet Liquid (stream 11). Adjust Mass flow of this stream until the Actual Volumetric Flow equal to Vl3.

Step 4d : Mix Actual Air Cooler Downstream Outlet Vapor (stream 9) and Actual Air Cooler Downstream Outlet Liquid (stream 11) to form Air Cooler Downstream (stream 12).

The remaining steps are same as "Simple Method For Compressor Settle Out Using HYSYS" by adjusting Settle Out Cond Actual Volumetric Flow same as Vv1+Vl1+V2+Vv3+Vl3.