Preparation of high purity hydrogen chloride by deep desorption of hydrochloric acid
1, device overview
1.1, device composition:
The depth of the company's design, such as hydrochloric acid is a byproduct of chemical plant 25~31% hydrochloric acid as raw material, the depth of the desorption of high purity HCl gas.
1.2, the main technical characteristics:
1.2.1, dry hydrogen chloride gas purity not less than 99.9% (Vol);
1.2.2, steam consumption (0.6~0.8Mpa): HCL <2.5t/t
1.2.2, HCL normal water dilute acid content is less than or equal to 0.5% (WT), 0.1%~0.2% (WT) up to the actual.
Short time anomaly in 2~5% (WT);
1.2.3, hydrogen chloride product outlet pressure 30~50KPaG (adjustable);
1.2.4, a full set of devices using DCS control, safety chain control alarm device is reliable and effective.
2, process principle and process description
2.1, the principle of technology:
Adding a kind of additive which can break the character of the hydrochloric acid in the hydrochloric acid, restrain the water pressure, so as to reach the goal of the maximum solution of the hydrogen chloride.
2.2, process flow description:
Hydrochloric acid tank settlement through a preheater preheating vaporization into the middle of a desorption tower, calcium chloride solution into the upper part of the desorption tower, under the action of gravity downward flow, mass transfer process through the packings and internals. At the same time, solution continuously by natural circulation heat siphon reboiler heating, so that steam is distilled to separate out and upward mobility. In this process, hydrogen chloride gas from hydrochloric acid and calcium chloride mixed solution of the automobile provided and is discharged from the top of the tower.
The calcium chloride solution is used as a co boiling point, and the partial pressure of the water vapor is suppressed by the partial pressure of the hydrogen chloride gas.
After being put forward by the hydrogen chloride saturated acid vapor by HCl condenser, the main device and the hydrochloric acid absorption system.
The bottom of the tower by dilute solution of calcium chloride containing trace hydrogen chloride and calcium chloride concentration into the flash part. Take the second effect countercurrent evaporation process, excess water by flash evaporation out, concentrated calcium chloride solution with calcium chloride circulating pump back to desorption tower circulating.
After the steam condenser is fully condensed, the water vapor is collected to the dilute acid water tank, and the water purification process or the sewage treatment is carried out.