Device and method for preparing hydrogen chloride gas through continuous method full hydrochloric acid analysis

Abstract

The invention relates to a device and method for preparing hydrogen chloride gas through continuous method full hydrochloric acid analysis. The device comprises an analysis system and a dilute sulfuric acid vacuum concentration system, wherein the analysis system comprises a hydrochloric acid analysis tower, a first-stage hydrogen chloride cooler, a second-stage hydrogen chloride cooler, a concentrated sulfuric acid drying tower and an acid mist separator; the dilute sulfuric acid vacuum concentration system comprises a dilute sulfuric acid flash tank, an acid-acid heat exchanger, a first-stage sulfuric acid concentration tank, a second-stage sulfuric acid concentration tank, a first-stage washing tower, a first-stage water vapor condenser, a second-stage washing tower, a second-stage water vapor condenser, a wastewater storage tank and a concentrated sulfuric acid intermediate tank. According to the device, high-concentration sulfuric acid serves as an extraction agent, and dilute heat of concentrated sulfuric acid is fully utilized; meanwhile, the concentrated sulfuric acid is continuously added from the top of the hydrochloric acid analysis tower so that the reflux ratio of thetop of the hydrochloric acid analysis tower can be reduced to the minimum, and the energy consumption is reduced to the maximum extent; a segmented vacuum concentration technology is adopted, and waste heat of later-stage acid is fully utilized, so that the heating steam consumption is reduced to the maximum extent, and technical support is provided for long-period continuous work of the device.

Description

technical field [0001] The invention relates to a dilute hydrochloric acid full-analysis device, in particular to a device and method for producing hydrogen chloride gas by continuous hydrochloric acid full-analysis. Background technique [0002] As we all know, HCl and H 2 The dilute hydrochloric acid formed by O has a high-boiling azeotrope (that is, its boiling point is higher than that of pure H 2 O and HCl), whose azeotropic point and azeotropic composition vary with pressure. Therefore, to treat dilute hydrochloric acid to make HCl and H 2 O separation, with simple distillation or stripping method is not acceptable. At present, there are two methods for the full analysis of industrialized dilute hydrochloric acid: [0003] 1. Calcium chloride method [0004] CaCl 2 Aqueous solution extraction breaks the azeotrope to recover HCl, that is, adding calcium chloride to dilute hydrochloric acid breaks the limit of its azeotropic point and separates hydrogen chloride. ...

AI Technical Summary

Problems solved by technology

[0006] (1) Due to the characteristics of high-concentration calcium chloride aqueous solution, it is easy to scale on the hole wall of the reboiler, resulting in a decrease in its heat transfer efficiency, and the acid content in the wastewater exceeds the standard; especially the dilute hydrochloric acid entering the system is composed of iron, zinc and other metal ions The formed chloride has a flocculation effect on the calcium chloride solution, which will directly cause the calcium chloride solution to crystallize and block equipment and pipelines; silicon micropowder and carbon micropowder and other thixotropic micropowders have a thickening effect, and gradually lead to calcium chloride solution Gradually scaling in the reboiler tube side will first cause the acid content in the wastewater to exceed the standard, and eventually cause the reboiler to fail to work normally

[0007] (2) The content of hydrogen chloride in the waste water is high. In order to prolong the operation cycle, the operating device of the chlor-alkali enterprise adopts technological measures to reduce the concentration of calcium chloride in hydrochloric acid. The concentration of HCl in the waste water discharged by the calcium chloride method device is much higher than the normal process target value of 1%; The actual value of HCl concentration in wastewater is about 2-3%. There are two main reasons for this. One is the insufficient heat and mass transfer caused by the design defect of the desorption tower.

Second, due to the influence of fouling in the reboiler, the heat transfer efficiency decreases

[0012] Adaptability ratio of pressure swing distillation dilute hydrochloric acid analysis technology to CaCl 2 The azeotrope-breaking method of aqueous solution extraction is good, and it is insensitive to most impurities in hydrochloric acid, but the acid cannot contain large molecular organic substances, which will cause the liquid to foam, thereby destroying the mass transfer of the filler.

Images