Process for concentrating aqueous hydrogen halide solutions

Abstract

The present invention relates to a method for concentrating an aqueous starting solution of hydrogen halide, in particular hydrochloric acid, comprising the following steps: - in a distillation unit (12), in the presence of an extractant, the aqueous starting solution of hydrogen halide extractive distillation of the solution, removal of hydrogen halide vapor and / or hydrogen halide gas (38) from the upper section of the distillation unit, removal of the extractant-containing solution (24) from the lower section of the distillation unit, - concentration of the extractant-containing solution removed from the lower section of the distillation device in the evaporation device (14), and - return of the extractant-containing solution concentrated in the evaporation device to the distillation device (22), · wherein said extractant-containing solution removed from the lower stage of the distillation device is concentrated by evaporation in said evaporation device at a pressure higher than atmospheric pressure.

Description

technical field [0001] The invention relates to a method for concentrating aqueous hydrogen halide solutions, especially hydrochloric acid, and a system for concentrating aqueous hydrogen halide solutions. Background technique [0002] Aqueous solutions of hydrogen halides such as hydrochloric acid accumulate in many processes, for example during production processes in the chemical industry and during waste incineration. In these cases, the solution is generally a relatively dilute solution that cannot be easily re-used since many chemical processes require the use of highly concentrated hydrogen halide solutions or even hydrogen halide gases. Furthermore, the transport costs of dilute solutions of this type are relatively high compared to the costs of more concentrated solutions, since large volumes of dilute hydrogen halide solutions have to be transported in terms of the amount of hydrogen halide species. Therefore, there is a need to concentrate dilute aqueous hydrogen...

AI Technical Summary

Problems solved by technology

Therefore, especially in the final evaporation stage, there is a risk of undesired crystallization of the extractant, which may cause the evaporation plant and, in the process, downstream of it in the process to become clogged, thus possibly causing a complete failure of the plant

Furthermore, the crystallized extractant has to be removed in a complex manner, which requires a high level of technical complexity and high labor costs and equipment downtime

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