Impurities like liquid water, solid particles, H₂O, and acid gases (CO₂, H₂S) accelerate equipment corrosion, clog pipelines, and disrupt subsequent process stability and product quality.

Pre-treatment uses a step-by-step purification strategy. First, the alcohol and amine method removes acidic gases. Then, molecular sieve adsorption technology is applied to remove water, heavy hydrocarbons, and mercury.

The selection of technology depends on raw gas composition, pressure conditions, product quality standards, as well as the overall capital expenditure (CAPEX) and operating expenses (OPEX).

It provides high dewatering efficiency even under low water vapor partial pressure, removes residual acid gas, is easy to operate, has a compact footprint, and recycles energy by using BOG from the re-liquefaction unit for regeneration.

Trace mercury is effectively adsorbed using specialized sulfur-impregnated coal-based activated carbon, while aromatic hydrocarbons are deeply purified using targeted, specialized adsorbents.