Technology for removing carbon dioxide in combined process for manufacturing soda ash and ammonium chloride

Abstract

The invention belongs to the technical field of a combined process for manufacturing soda ash and ammonium chloride, and especially relates to a technology for removing carbon dioxide in the combined process for manufacturing soda ash and ammonium chloride. According to the invention, solid sodium bicarbonate is separated from a liquid discharged from a decarburization tower, such that a mother liquid is obtained; the mother liquid is divided into two parts which are A1 and A2; ammonium chloride is separated from a liquid discharged from an ammonium chloride producing process, such that a mother liquid B is obtained; the mother liquid B is processed through ammonia adsorption, and calcium and magnesium ionic impurities are removed from the mother liquid B; the mother liquid B is mixed with A1; the temperature of the mixed liquid is regulated to 18 to 24 DEG C, and carbon dioxide is removed from the mixed liquid in the decarburization tower. With the technology provided by the invention, a carbon dioxide removal reaction can be normally carried out with no internal or external cooling device arranged in the decarburization tower. That is to say, during the process since the decarburization solution is delivered into the decarburization tower to the decarburization solution is discharged from the tower, no heat exchanging by cooling is required. The decarburization tower can smoothly operate in a long period, wherein a task cycle is more than 60 days. With the technology, the carbon dioxide absorption effect is good, and a utilization rate is higher than 99.6%.

Description

technical field [0001] The invention belongs to the technical field of combined soda production, and in particular relates to a carbon dioxide removal process in the combined soda production. Background technique [0002] The conventional combined soda production method uses the mother liquor of separated ammonium chloride for the removal of carbon dioxide, and the ammonia mother liquor after absorbing ammonia is used as the decarburization liquid. The temperature of the decarburization liquid is 28-48°C. A cooler needs to be installed inside or outside the decarburization tower. The decarburization liquid in the decarburization tower is cooled by heat exchange with the cooler installed inside or outside. The reaction product sodium bicarbonate is easily affected by the large temperature difference during heat exchange. Accelerated precipitation and deposition on the surface of the decarburization tower and cooler, resulting in scarring and blockage of the decarbonization to...

AI Technical Summary

Problems solved by technology

At present, the method of removing calcium and magnesium ion impurities in the clarification tank is used, but due to the high viscosity of the mother liquid and the high density of the mother liquid, the sedimentation velocity of the impurities in the clarification tank is inversely proportional to the viscosity of the mother liquid and proportional to the density difference between the impurities and the mother liquid. The settling speed is small, it is difficult to effectively remove the calcium and magnesium ion impurities in the mother liquor system, resulting in the accumulation of calcium and magnesium ion impurities in the mother liquor system, resulting in the deterioration of the mother liquor conditions, and bringing many adverse effects to the production of combined alkali, such as: the removal of carbon dioxide Low rate, low salt dissolution rate, small sodium bicarbonate crystals, high salt content in sodium bicarbonate entering the sodium carbonate production process, increased washing water equivalent, mother liquor expansion, etc.

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