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Gas Treating Systems

Modern gas production requires the removal of corrosive contaminates such as hydrogen sulphide (H2S) and carbon dioxide (CO2) prior to further processing or transportation. Various types of amine-based absorbents (such as MEA, DEA, or MDEA) can be used for custom-designed units, which will remove H2S and CO2 to meet the sales gas specification.

The equipment can be totally mounted on skids and pre-packaged in our fabrication facilities to reduce on-site installation expense.

Natural gas streams with low content H2S can be sweetened using iron sponge as an absorbent. However, this is a batch process requiring replacement of iron sponge upon saturation with H2S, which consumes the active chemical in the sponge.

Adsorption units using molecular sieve (mole sieve) have also been designed for adsorption of H2S and CO2 from low volume gas streams, as well as propane and butane in the liquid phase.

Sulphur Recovery Units (SRUs)

Air pollution is a matter of urgent public concern, particularly as the trend towards an industrial society encroaches on traditional agricultural societies around the world. To cope with the increasing volume of industrial contamination being released into the atmosphere, regulatory agencies are focused more and more on the reduction and control of emissions at the source.

Tightening of emission standards for sulphur dioxide has created a need for economically processing small streams to eliminate or reduce sulphur dioxide emissions. The simplest and most obvious way to accomplish this in the oil fields is to use partial oxidation of hydrogen sulphide to produce elemental sulphur, which can then be precipitated as a solid, rather than the full oxidation product which produces gaseous sulphur dioxide (SO2).

In a sulphur recovery unit, the Claus process makes use of this reaction in combination with several stages of separation, reheating and catalytic conversion to produce a final off-gas that is relatively low in sulphur dioxide. The Claus process is well understood and predictable, and it offers the most reliable basis for developing new low-cost equipment for conversion of hydrogen sulphide to sulphur, thus eliminating pollution caused by flaring of by-product hydrogen sulphide associated with petroleum.

Exterran brings many years of experience in engineering and manufacturing of both large and small sulphur recovery plants of scaleable design which are economic (low capital investment) and efficient (low operating cost). We have demonstrated our ability to provide world-class equipment in some of the most challenging locations in the world.

Tail Gas Treating Unit (TGTU)

A new tail gas treating unit processes 123.9 MSCFH of waste gas from the SRU. The process utilizes catalytic reaction to convert 1.28 mol % residual sulphur compounds in the waste gas to H2S. The H2S is then removed by amine treating and recycled to the SRU for sulphur recovery. The treated tail gas, which is almost free of H2S, is incinerated and discharged to the atmosphere.