00 gas treatment foreni 2016.pdf

8/18/2019 00 Gas treatment forENI 2016.pdf

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GAS TREATMENT STEPS

Introduction


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MISKAR GAS

Introduction


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1.In transmission multiphase

lines supplying the plant

slugging is common. The

arrival of “slugs” at

production or processing

equipment impacts the

operation of productionfacilities negatively, causing

both mechanical problems

and process problems.

2. Slug catchers are used to dissipate the energy of the liquid slugs, tominimize turbulence, to ensure that the gas and liquid flow rates are

low enough so that the stratified flow regime and subsequentlygravity segregation can occur.

Introduction


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3. Separation of the distinct phases, in 3-phase separator.

4. Overhead gas from the three-phase separator is recompressed where necessary for use as fuel gas.

5. Hydrocarbon condensate recovered from natural gas may beshipped without further processing but is typically stabilized to

produce a safe transportable liquid. Unstabilized condensates

contain a large percentage of methane and ethane, which willvaporize easily in storage tanks.

Introduction

6. Stabilization is the full removal of light fractions from thecondensate, usually achieved by distillation. Stabilized liquid will

generally have a vapor pressure specification (Reid vapor

pressure of


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8. Depending on the pressure at the plant gate, the next step inprocessing will either be inlet compression to an “interstage”pressure, typically 300 – 400 psig, or be dew point control and

natural gas liquid recovery.

9. Water dew point control is required to meet specifications and to

control hydrate formation. Gas hydrate formation is a majorconcern in pipeline and natural gas transportation industries as it

causes choking/plugging of pipelines and other related problems.

10.Hydrocarbon dew point or hydrocarbon liquid recovery involvescooling the gas and condensing out the liquids.

11.Refrigeration is performed either by auto-refrigeration due to apressure drop across a valve or by an external mechanical

refrigeration process.

Introduction


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14.Where there is no available gas pipeline, separated associatedgas may be conserved by compression and re-injection into

producing formations for eventual recovery and sales.

15.Also, in gas condensate reservoirs, the gas is often re-injected,or “cycled,” to enable higher net recovery of valuable liquid

hydrocarbons from the reservoir.

Introduction

12.The temperature to which the gas is cooled depends onwhether it is necessary to meet a sales gas hydrocarbon dewpoint specification or whether substantial liquid recovery is

desired.

13.Sales gas pressure is approximately 1000 psig in Tunisia. If

gas is produced at lower pressures, it is compressed


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Key parameters to be respected

Introduction


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The temperature at which water vapor starts to condense from a gasmixture (water dew point), or at which hydrocarbons start to condense

(hydrocarbon dew point).

Heavy hydrocarbons are removed to control the hydrocarbon dew point

of the gas and prevent liquid from condensing in pipeline transmissionand fuel systems.

Introduction


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Carbon dioxide (CO2), hydrogen sulfide (H2S), andother sulfur-containing species such as mercaptans

are compounds that require complete or partial

removal. These compounds are collectively known as

“acid gases.” H2S when combined with water forms a weak sulfuric

acid, whereas CO2 and water form carbonic acid, thus

the term “acid gas.”

Natural gas with H2S or other sulfur compounds

present is called “sour gas,” Both H2S and CO2 are very undesirable, as theycause corrosion and present a major safety risk.

Introduction


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Introduction


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Introduction


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00 gas treatment foreni 2016.pdf

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