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13

Recovery, Separation, and
Fractionation of Natural Gas Liquids

13.1 INTRODUCTION

The material presented in this chapter includes two parts: the recovery and
separation of natural gas liquid (NGL) constituents, and methods of
fractionation into finished product streams suitable for sale. In the first
part, several alternatives for the separation and recovery of NGL are
detailed. They are essentially based on phase change either by using energy
separating agent (ESA) or mass separating agent (MSA). Thus, partial
liquefaction or condensation of some specific NGL constituents will lead
to their separation from the bulk of the gas stream. Total condensation is
also a possibility. The role of the operating parameters that influence
phase change, hence NGL separation from the bulk of gas, is discussed.
The second part of the chapter covers materials on fractionation facilities
that are recommended to produce specification quality products from
NGL. Types of fractionator with recommended feed streams as well as
produced products are highlighted in this part.

13.2 RECOVERY AND SEPARATION OF NGL
13.2.1 Options of Phase Change
To recover and separate NGL from a bulk of gas stream, a change in
phase has to take place. In other words, a new phase has to be developed
for separation to occur. Two distinctive options are in practice depending
on the use of ESA or MSA.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.