Hydrocarbon removal from Natural Gas

Introduction

Natural gas come about in underground reservoirs distinctly or in link with crude oil. The leading types of hydrocarbons produced from natural gas. They are methane (CH4) and varying amounts of higher-molecular-weight hydrocarbons. Those are included from ethane (CH3CH3) to octane [CH3(CH2)6CH3].

Natural gas is mainly a combination of combustible hydrocarbons. Many natural gases similarly contain nitrogen (N2) as well as carbon dioxide (CO2) and hydrogen sulfide (H2S). Natural gas was normally made as a by-product of petroleum production. In this article, we will understand the production process of hydrocarbon from Natural Gas.

Description

• At present, raw natural gas is recovered from three types of wells as Oil wells, Gas wells, and Condensate wells.
• Natural gas that originates from oil wells is usually called associated gas.
• This gas may occur distinct from oil in the formation.
• It is also dissolved in the crude oil.
• Natural gas from gas and condensate wells is named non-associated gas.
• Gas wells normally produce raw natural gas by themselves.
• Condensate wells produce free natural gas. That is also along with a semi-liquid hydrocarbon condensate.
• The source of the natural gas ordinarily occurs in mixtures with other hydrocarbons such as ethane, propane, butane, and pentanes.
• Moreover, raw natural gas comprises water vapor, hydrogen sulfide (H2S), carbon dioxide, helium, nitrogen, and other compounds.
• Actually, natural gas liquids (NGLs) that are associated hydrocarbons may be very valued by-products of natural gas processing.
• Natural gas liquids comprise ethane, propane, butane, iso-butane, and natural gasoline.

Uses of NGLs

• Improving oil recovery in oil wells
• As long as raw materials for oil refineries or petrochemical plants
• As sources of energy

Gas Refining

All materials other than methane were removed during processing or refining.

By-products of gas processing

• Ethane
• Propane
• Butanes
• Pentanes
• Higher molecular- weight hydrocarbons
• Hydrogen sulfide
• Thiols (mercaptans)
• Carbon dioxide
• Water vapor,
• Sometimes helium and nitrogen

Natural gas is a vigorous component of the world’s source of hydrocarbons. It is still composed mainly of methane so it is by no means as pure. The gas must be sent over some purification steps to produce pure methane and highermolecular-weight hydrocarbons. That would be used for other drives. Gas processing covers of splitting all of the several hydrocarbons and liquids from the clean natural gas.

Main transportation pipelines commonly carry out limits on the face of the natural gas. That is permissible into the pipeline. That before the natural gas may be conveyed it must be purified. Though the ethane, propane, butane, and pentanes must be detached from natural gas. This does not mean that they are all left-over products. Gas processing is essential to make sure that the natural gas planned for use is as clean and unadulterated as possible. It would make it the clean-burning and globally sound energy choice.

Natural gas is used by consumers. That is greatly different from the natural gas that is transported from underground up to the wellhead. Though the processing of natural gas is in various respects less complex than the processing of crude oil. That is similarly as needed before its use by end users.

Absorption process

• The absorption method of extraction is very alike to using absorption for dehydration.
• The key difference is that, in the absorption of natural gas liquids, absorbing oil is used as opposed to glycol.
• This absorbing oil has a similarity for natural gas liquids.
• That is in abundant the same manner as glycol has a similarity for water.
• It is called lean absorption oil before the oil has picked up any natural gas liquids.
• The oil absorption process includes the countercurrent contact of the lean.
• That is the oil with the incoming wet gas with the temperature and pressure conditions programmed to make the most of the dissolution of the liquefiable components in the oil.
• The rich absorption oil covering natural gas liquids, departures the absorption tower over the bottom.
• The rich oil is nurtured into lean oil.
• The mixture is heated there to a temperature beyond the boiling point of the natural gas liquids.
• That temperature would be below that of the oil.
• This process permits for the recovery of around ;

• 75% by volume of the butanes
• 85–90% by volume of the pentanes
• Higher boiling constituents from the natural gas stream.

• The simple absorption process above may be altered to recover its success.
• It can be modified to target the extraction of particular natural gas liquids.
• For instance, the lean oil is cooled over refrigeration in the refrigerated oil absorption method.
• In this process, propane recovery may be up of 90 percent by volume.
• Nearly 40 percent by volume of the ethane can be removed from the natural gas stream.
• Higher boiling natural gas liquids may be near to 100 percent by volume using this process.

Non-cryogenic absorption

• For recovery of liquefied petroleum gas uses non-cryogenic absorption.
• That is used to recover ethane, propane, and higher boiling constituents from natural gas streams.
• The absorbed gases in the ironic solvent from the lowest of the absorber column are fractionated in the solvent regenerator column.
• That split up gases as an overhead fraction and lean solvent as a bottoms fraction.
• The lean solvent is pre-saturated with absorber overhead gases after heat recuperation.
• The chilled solvent runs in the top of the absorber column.
• The separated gases are directed to storage.
• The operation of the plant may be switched on-line from ethane plus recovery to propane plus recovery deprived of touching the propane recovery levels.
• The AET liquefied petroleum gas plant usages lower boiling lean oils.
• There are no solvent face requirements for utmost applications.
• For more details visit:https://www.technologiesinindustry4.com/2021/09/hydrocarbon-removal-from-natural-gas.html

Mansoor Ahmed Chemical Engineer,Web developer