System suitable for preparing carbon dioxide from decarbonized LNG (Liquefied Natural Gas)

The invention discloses a system suitable for preparing carbon dioxide from decarburized LNG (Liquefied Natural Gas). According to the system, a two-tower variable-pressure variable-temperature adsorption molecular sieve is adopted for dehydration, and low-pressure regenerated gas energy and regenerated gas utilization are realized; in the aspect of desulfurization, the consumption of circulating water is reduced by compression heat of two-stage compression of a compressor, and H2S and COS are removed at the same time; according to the invention, only one subcooler and one rectifying tower are adopted to directly rectify to prepare LCO2, the dealkylation device is arranged behind the desulfurization process, a desulfurization heat source is utilized, and a preheater in front of the dealkylation tower and an air cooler behind the tower are arranged to fully utilize the desulfurization heat source, so that the heat source and the cold energy consumption of circulating water are reduced; according to the inventi