Gas Sweetening and CO2 extraction from Syngas plants

Gas treatment plants often need technologies to remove contaminants like CO2 (acid removal) and sometimes H2S from the Natural Gas (NG) before further processing and liquefying the gas (LNG). This is done to avoid corrosion issues with downstream process equipment, meeting LNG product specifications, and last but not least, meeting environmental standards.

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In general, the purified NG should not exceed 50 ppm (vol) CO2 and 1 ppm H2S (vol) before the LNG production.

Syngas (from synthesis gas) is a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, gasification of coal, and some types of waste-to-energy gasification facilities.

The name comes from their use as intermediates in creating synthetic natural gas (SNG) and for producing ammonia or methanol.

Syngas consists primarily of hydrogen, carbon monoxide, and very often some carbon dioxide, and has less than half the energy density of NG.


Union Engineering has over many years developed various technologies and gained strong experience for such processes.

The absorption process generally uses an organic solvent that absorbs the CO2 and H2S as a function of its partial pressure. The most commonly used solvents are based on Methyl DiEthanolAmine (MDEA).

These amines work as an aqueous solvent and selectively absorb CO2 and H2S from the NG stream in the absorber tower.

The regeneration (stripping of acid gases) is done mainly by a change in pressure (flashing), and by application of heat via a reboiler in the stripping column.

Due to high CO2 loadings, circulation rates are optimized and hence results in low energy consumption.

After stripping off the gaseous CO2 it can be liquefied in our RBU plant and purified to highest food grade quality, and thereby the former syngas is transferred into a merchant product.



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