Method for capturing carbon dioxide from coal gas

The invention discloses a method for capturing carbon dioxide from coal gas, which comprises the following steps: washing the coal gas by using a methanol solution, cooling the washed coal gas, and separating a liquid phase containing carbon dioxide from the cooled coal gas. The method comprises the following steps: washing the coal gas by using a methanol solution to remove most of sulfides in the coal gas, cooling the desulfurized coal gas to convert carbon dioxide in the coal gas from a gas state to a liquid state, and separating the liquid carbon dioxide from a gas-liquid mixture to obtain a liquid carbon dioxide product; according to the method, a carbon dioxide product with extremely low sulfide content is obtained by using a simple recovery process, and meanwhile, the energy consumption of carbon dioxide trapping is greatly reduced. 本发明公开了一种从煤气中捕集二氧化碳的方法，用甲醇溶液洗涤煤气，将洗涤后的煤气降温，从降温后的煤气中分离出含有二氧化碳的液相。本发明首先采用甲醇溶液对煤气进行洗涤，使得甲醇溶液脱除煤气中绝大部分硫化物，再对脱硫后的煤气进行冷却，将煤气中二氧化碳从气态转变为液态，然后将液态二氧化碳从气液混合中分离，得到液态二氧化碳产品；本发明使用简洁的回收流程