What does LNG mercury removal mean?
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The feed gas will arrive at the platforms as gas ready for liquefaction, where activated carbon guard beds will be installed to remove any traces of mercury before the gas is processed into LNG.
The description is too brief to be clear; the performance of properly processed LNG already meets the required standards, so there is no need for further mercury removal. Mercury removal is generally carried out only during the purification stage of the feed gas, along with tasks such as desulfurization
Doesn’t this sentence mean that mercury removal is required before entering the cryogenic tank or before liquefaction?
Trace amounts of mercury in the feed gas can react with the plate-fin heat exchangers made of aluminum alloy in the cold box, resulting in the formation of aluminum amalgam; therefore, it is necessary to pass the gas through a desulfurization and demercurization tower before it enters the cold box
It should be the process mentioned on the first floor: purifying the gas to remove mercury and then liquefying it into LNG downstream
Mercury in the feed gas can corrode the aluminum fins in the cold box; therefore, the feed gas must be demercurized before entering the cold box.
A sulfur-loaded activated carbon adsorption bed is used to remove trace amounts of mercury. Generally, mercury removal equipment is installed regardless of whether mercury is detected in the feed gas; it is an adsorption tower equipped with sulfur-loaded activated carbon adsorbents.
Even a small amount of mercury, which remains liquid at low temperatures, will continuously corrode the aluminum alloy in LNG liquefaction plants, forming an amalgam.