Removing contaminants from natural gas

Abstract

A process for removing contaminants from a natural gas feed stream including water and sour species is provided, which process comprises the steps of cooling the natural gas feed stream in a first vessel (12) to a first operating temperature at which hydrates are formed and removing from the first vessel (12) a stream of dehydrated gas (34); and cooling the dehydrated gas in a second vessel (14) to a second operating temperature at which solids of the sour species are formed or at which the sour species dissolve in a liquid and removing from the second vessel (14) a stream of dehydrated sweetened gas (62).

Description

RELATED APPLICATIONS [0001] This application claims priority to co-pending U.S. patent application having Ser. No. 10 / 772,621, filed Feb. 5, 2004, which claims priority to Australian patent application having serial number 2003900534, filed Feb. 7, 2003. Co-pending U.S. application having Ser. No. 10 / 772,621 is herein incorporated by reference in its entirety.FIELD OF INVENTION [0002] The present invention relates to a process for removing a contaminant from a natural gas feed stream. BACKGROUND [0003] Natural gas from either production reservoirs or storage reservoirs typically contains water, as well as other species, which form solids during the liquefaction to produce liquefied natural gas (LNG). It is common practice for the natural gas to be subjected to a dehydration process prior to the liquefaction. Water is removed to prevent hydrate formation occurring in pipelines and heat exchangers upstream of the liquefaction vessel. [0004] If water is not removed, solid hydrates may ...

AI Technical Summary

Benefits of technology

This process efficiently removes water and sour species, reducing the risk of hydrate formation and corrosion, while simplifying the dehydration and sweetening process, thereby improving operational efficiency and reducing costs.

Problems solved by technology

H2S is a contaminant of natural gas that must be removed to satisfy legal requirements, as H2S and its combustion products of sulphur dioxide and sulphur trioxide are also toxic.

Furthermore, H2S is corrosive to most metals normally associated with gas pipelines so that processing and handling of a sour gas may lead to premature failure of such systems.

Existing dehydration and gas sweetening processes are extremely complex and expensive.

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