Sizing Gas/Liquid Horizontal Separators Handling Nonstable Multiphase Streams

Fig. 1—Schematic of a gas/liquid separator.

The sizing procedures for all of the process equipment in the oil and gas industry share a common assumption: The stream flow rate measured at the inlet is always constant or stable. This principle works fine for plants where the process conditions are controlled, but it does not apply to primary production facilities where the streams come from multiphase flowlines or wells. The sizing procedure described in the paper allows one to size horizontal gas/liquid separators considering nonstable flow rate at the inlet or fluctuations in the liquid fraction on the same stream.


From a design standpoint, separators are split into three stages (or sections).

Primary Stage. This is a mechanical operation; it uses an inlet diverter so that the momentum of the liquid in the gas causes the largest droplets to impinge on the diverter, forming droplets that are separated by gravity. The gas stream flows to the disengagement section.

Secondary Stage. Liquid drops immersed in the gas stream are separated by gravity. This separation is governed by the settling liquid-drop velocity inside the gas phase. This velocity must be higher than gas-stream velocity to allow the drop to settle to the liquid phase.

Tertiary Stage. This occurs on the mist eliminator. This is a device that allows small-sized droplets to coalesce to larger drops, which fall down by gravity to the liquid phase.

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 169444, “A Method To Size Gas/Liquid Horizontal Separators Handling Nonstable Multiphase Streams,” by J.L. Hernandez-Martinez, Pemex, and V. Martinez-Ortiz, Schlumberger, prepared for the 2014 SPE Latin American and Caribbean Petroleum Engineering Conference, Maracaibo, Venezuela, 21–23 May. The paper has not been peer reviewed.
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Sizing Gas/Liquid Horizontal Separators Handling Nonstable Multiphase Streams

01 December 2014

Volume: 66 | Issue: 12


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