LNG liquefaction unit – Heavy hydrocarbon removal
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For LNG liquefaction plants, where the natural gas contains a high level of heavy hydrocarbons, how should conventional hydrocarbon removal units be designed and what processes should be used?
Fractionating towers are generally used in LNG liquefaction units to remove heavy hydrocarbons. The main processes include: 1. Adsorption-desorption process (PSA); 2. Cryogenic condensation method. The choice of specific process depends on factors such as the composition of the natural gas, site conditions, and economic considerations. .
Two methods: adsorption, and separation using a cryogenic box at low temperatures. Low-temperature separation has more advantages.
Low-temperature separation: At what temperature can complete separation be achieved?
At a raw gas temperature of over 70 degrees, alkanes with more than 4 carbon atoms are almost completely separated, preventing blockages in the cold box； A small amount of C3 and below will remain in the LNG, which can also help increase its calorific value to some extent ； This method is widely used in coalbed methane well heads