Research and Adaptability Analysis on Acid Gas Removing Technology in Floating LNG Plant

Associated gas in offshore oil field is a kind of clean and efficient energy resource. Institute of Cryogenics and Superconductivity Technology at HIT has developed a floating LNG liquefaction plant for the associated gas. Based on the offshore oil field associated gas characteristics and the reaction mechanism between amine solutions and CO₂, the CO₂ removal process using MDEA+MEA aqueous solutions and its flow diagram are given. It analyses the adaptability of the CO₂ removal cycle on the offshore oil associated-gas flux and CO₂ content in the feed gas. The analysis result shows that the circulating amount of amine solutions should be 500 kmol/h~200 kmol/h and the reboiler heat load should be 600 kW~200 kW, when the CO₂ mole fraction is 0.45%~5.54% in the associated gas, and the capacity of the purification system is 11.6 × 10⁴ Nm³/d. The result provides guidelines for the design and operation of the small-scale floating LNG liquefaction device.