Natural Gas Contaminants

below are list of natural gas contaminants:
- Acid Gases (CO2)

- Acid Gases (Sulphur Compound)
- Mercury (Hg)
- Water (H20)
- Heavy Hydrocarbons (C5+)



Why those contaminants usually need to be removed?
- Acid Gases (CO2)
CO2 freezes on low temperature (below - 50 degC), it may blocked the equipments
- Acid Gases (Sulphur Compound)
Total Sulphur compound shall not be more than 100 grains /Nm3 in LNG plant
- Mercury (Hg)
Mercury (in the presence of water) damages aluminum properties
- Water (H20)
Below 20 degC, water and hydrocarbon will form solid substance called hydrate which very difficult to remove
- Heavy Hydrocarbons (C5+)
C5+content in LNG shall be no more than 0.1% mole

Contaminants limits:
CO2 < 100 ppmv (freezing and equipment plugging)
H2S < 4 ppmv (sales gas specification)
H20 < 1 ppmv (freezing and equipment)
HG 0.01 micro gr/Nm3 (corrosion in aluminum)