Chemical & Process Technology

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Natural gas is used in industry and household to provide heating energy. It is explored from gas well, treated, transported to customer via large and long pipeline. It is become non-cost effective once the pipeline length is exceeded 3000 - 3500 km. Thus, another mode of transportation, Liquefied Natural Gas (LNG) is considered cost effective.

Liquefied Natural gas (LNG) is a process of cooling down the natural gas to form liquid for easy storage and transportation. A LNG is normally contains of Methane (CH4) which is more than 90% and other light hydrocarbon such as Ethane (C2H6), Propane (C3H8), Butane (C4H10) and Nitrogen (N2) inert gas. LNG is non-corrosive, non-toxic, non-carcinogenic, odorless and colorless. However, it is flammable and explosive and create greenhouse effect to environment.

Natural gas may contains of other contaminants such as Carbon Dioxide (CO2), Hydrogen Sulfide (H2S), Water (H2O), Mercury (Hg), Nitrogen (N2), Helium (He), BTEX, etc. These contaminants potentially cause corrosion, cracking and freezing problem in the natural gas liquefaction process. and drop in Higher Heating Value (HHV). Thus they shall be removed prior to liquefaction process. Read more in "Typical Gas Processing Flow Scheme" and "Gas Processing, NGL Extraction & LPG Fractionation".



Entire LNG supply chain consist of LNG production, transportation and regassification process. Natural gas produced from gas well will be treated in order to remove contaminants as mentioned above prior feed to cryogenic section for liquefaction. In the liquefaction process, Natural gas is chilled down to about -160 degC. Ethane (C2), Propane (C3) and Butane (C4) will be recovered as Ethylene feedstock and production of Liquefied Petroleum Gas (LPG). Heavy hydrocarbon (C5+) will be removed from natural gas and sale as stablised condensate. In the process of liquefaction, the natural gas volume will reduce roughly about 600 times and this ease for LNG storage and transportation. Once the LNG is produced, it will store in LNG tank at atmospheric pressure prior pumped to LNG tanker for transportation.

LNG pumped into LNG tanker via LNG loading station will be send to customer. Good insulation is one of the key factor in keep LNG in liquid form during the transportation process. Any vaporized LNG will be compressed and used as fuel to generate power and drive all equipment in LNG tanker.

Once the LNG tanker arrived at LNG terminal, it is unloaded from the LNG tanker to the LNG storage tank. From the LNG storage, LNG is pumped and regassified using seawater or closed loop heated water. Vaporized natural gas is then injected into natural gas grid and deliver to customer.

Following are few video clips for the LNG supply chain, LNG liquefaction and terminal.