Ammonia-carbon separation process

Abstract

The invention provides an ammonia-carbon separation process. The process comprises the step of carbon dioxide absorption, wherein a gas mixture sequentially makes contact with carbonized ammonia water and strong ammonia water in a carbon dioxide washing tower, carbon absorbing liquid is formed, the carbon absorbing liquid makes contact with a gas mixture in a carbon dioxide absorption tower, and ammonium carbamate liquid is obtained. According to the process, synergism of the carbon dioxide absorption tower and the carbon dioxide washing tower is initiatively utilized, carbon dioxide is separated from the gas mixture to the greatest extent, to be specific, the carbon dioxide absorption tower adopts the carbon absorbing liquid for absorbing carbon dioxide in the gas mixture, while carbon dioxide washing tower adopts carbonized ammonia water as the main medium and strong ammonia water as the auxiliary medium for precisely absorbing carbon dioxide, therefore the content of carbon dioxide in obtained coarse ammonia gas can be controlled below 50 ppm, then ammonia is separated from the coarse ammonia gas, and finally pure ammonia containing no carbon dioxide or water is obtained. By means of the ammonia-carbon separation process, thorough separation of ammonia and carbon dioxide is achieved in real sense, the ammonia-carbon separation effect is improved, and it is helpful to increase economic benefits.

Description

technical field [0001] The invention relates to the field of gas separation, in particular to a process for separating ammonia and carbon dioxide mixed gas. Background technique [0002] A large amount of mixed gas containing ammonia and carbon dioxide will be produced in the industrial process of synthetic ammonia, urea, melamine, etc. Based on economical and environmental considerations, it is usually necessary to separate the mixed gas into pure ammonia and carbon dioxide. [0003] Since ammonia and carbon dioxide are easily combined to form ammonium bicarbonate, ammonium carbamate and other substances, physical methods such as pressure swing adsorption cannot be used for separation. Therefore, most of the existing ammonia-carbon separation processes form NII by introducing water. 3 -CO 2 -II 2 O ternary system and then separated. However, the phase equilibrium relationship of the ammonia, carbon dioxide, and water ternary system is very complicated, and it does not fo...

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Problems solved by technology

[0009] The technical problem solved by the present invention is to overcome the defects that ammonia and carbon dioxide cannot be completely separated and consume a lot of energy in the ammonia-carbon separation process in the prior art, and then provide a method that can completely separate the ammonia and carbon dioxide in the mixed gas. Separate and economical ammonia-carbon separation process

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