Hydrochloric Acid

In this report, processes for producing, recovering and purifying hydrochloric acid and its anhydrous form, hydrogen chloride, are studied. The processes for producing hydrogen chloride include the following routes:

• Reaction of chlorine and hydrogen;
• Reaction of alkali chloride (chloride of sodium or potassium) with sulfuric acid (using Mannheim mechanical muffle furnaces or fluidized bedreactors) or with sulfur dioxide, steam and air (Hargreaves process).

Large amounts of hydrogen chloride are by-produced in many industries. Processes for purification of such by-produced hydrogen chloride to remove various impurities are described and evaluated.

One important application of hydrochloric acid is in the pickling of steel. The reclaiming of hydrochloric acid from spent pickle solution is discussed, and one process, using a fluidized bed reactor, is evaluated. Certain unit operations used in the recovery and/or purification processes described in this report are discussed.