A method for producing a high-purity hydrogen chloride gas comprises performing a purification process that includes the steps 1) to 3) below on a byproduct hydrogen chloride gas: 1) a crude hydrochloric acid generation step of allowing water to absorb the byproduct hydrogen chloride gas; 2) a volatile organic impurity-removed hydrochloric acid generation step of bringing the crude hydrochloric acid obtained in the step 1) into contact with an inert gas at a liquid temperature of 20 to 45° C. to dissipate volatile organic impurities; and 3) a high-purity hydrogen chloride gas generation step of supplying the volatile organic impurity-removed hydrochloric acid obtained in the step 2) to a distillation column and performing distillation under conditions of a column bottom temperature of higher than 60° C. and 108° C. or lower and a column top temperature of 60° C. or lower to distill out a high-purity hydrogen chloride gas.

The present invention relates to a method of purifying waste hydrochloric acid, and more particularly, to a method of purifying waste hydrochloric acid which includes preparing an extraction solution by dissolving an extractant in an organic solvent (S1), extracting metallic components with the organic solvent by adding the extraction solution to the waste hydrochloric acid (S2), separating a waste hydrochloric acid layer and the organic solvent containing the metallic components (S3), and obtaining purified hydrochloric acid by recovering the separated (fractionated) waste hydrochloric acid layer (S4), wherein the extractant is used in an amount of 40 moles or more based on 1 mole of iron (Fe) included in the waste hydrochloric acid, and the waste hydrochloric acid and the extraction solution are mixed in a volume ratio of 1:0.1 to 1:1.

Solid saccharides are produced from an aqueous saccharide solution in a process, where the aqueous saccharide solution is admixed with a carrier liquid in which the saccharides are insoluble and that has a boiling point higher than that of water to obtain an aqueous admixture, and where the aqueous admixture is subjected to an evaporation step. The heat for the evaporation is at least partially supplied by a heated surface area to yield a vapor fraction including water and a residue fraction including solid saccharides and carrier liquid.

A unit for recovering hydrogen chloride from an aqueous liquid which includes hydrogen chloride and is contaminated with compounds of low or no volatility, the unit having an evaporation unit for forming, from the liquid, a vapour which contains hydrogen chloride and a liquid concentrate which is contaminated with the compounds of low or no volatility, a first distillation unit for separating the hydrogen-chloride-containing vapour into a first top product and a first bottom product, and a second distillation unit for separating a hydrogen-chloride-containing aqueous fluid into a second top product and a second bottom product, one of these two distillation units being configured to be able to implement therein a distillation above the ambient pressure, and the other of these two distillation units being configured to be able to implement therein a distillation below the ambient pressure.

A method for producing aqueous hydrochloric acid from flue gases is provided. The method comprises conveying water to a first scrubber (102, 202, 302, 402, 502, 602, 702) or to a line (112b, 212b, 312b, 412b, 512b, 712b, 712c) to use the water in a scrubbing liquid of the first scrubber. The method also comprises providing flue gas containing chlorides into the first scrubber (102, 202, 302, 402, 502, 602, 702) and scrubbing the flue gas containing chlorides with the scrubbing liquid by contacting the flue gas with the scrubbing liquid in the first scrubber (102, 202, 302, 402, 502, 602, 702). Dilute hydrochloric acid and a flue gas derivate (104, 204, 304, 404, 504, 704) are produced. The method comprises letting out at least some of the dilute hydrochloric acid from the first scrubber (102, 202, 302, 402, 502, 602, 702) as a scrubber bleed, separating solids suspended by the scrubber bleed in a solids separator (192, 592, 692), conveying the scrubber bleed from the solids separator (192, 592, 692) into an evaporation vessel (194, 594, 694) and concentrating the scrubber bleed in the evaporation vessel (194, 594, 694) to produce hydrochloric acid vapor having a concentration of 5-22 wt-%. A corresponding system is also provided.

A unit for recovering hydrogen chloride from an aqueous liquid which includes hydrogen chloride and is contaminated with compounds of low or no volatility, the unit having an evaporation unit for forming, from the liquid, a vapour which contains hydrogen chloride and a liquid concentrate which is contaminated with the compounds of low or no volatility, a first distillation unit for separating the hydrogen-chloride-containing vapour into a first top product and a first bottom product, and a second distillation unit for separating a hydrogen-chloride-containing aqueous fluid into a second top product and a second bottom product, one of these two distillation units being configured to be able to implement therein a distillation above the ambient pressure, and the other of these two distillation units being configured to be able to implement therein a distillation below the ambient pressure.

A method for producing aqueous hydrochloric acid from flue gases is provided. The method comprises conveying water to a first scrubber (102, 202, 302, 402, 502, 602, 702) or to a line (112b, 212b, 312b, 412b, 512b, 712b, 712c) to use the water in a scrubbing liquid of the first scrubber. The method also comprises providing flue gas containing chlorides into the first scrubber (102, 202, 302, 402, 502, 602, 702) and scrubbing the flue gas containing chlorides with the scrubbing liquid by contacting the flue gas with the scrubbing liquid in the first scrubber (102, 202, 302, 402, 502, 602, 702). Dilute hydrochloric acid and a flue gas derivate (104, 204, 304, 404, 504, 704) are produced. The method comprises letting out at least some of the dilute hydrochloric acid from the first scrubber (102, 202, 302, 402, 502, 602, 702) as a scrubber bleed, separating solids suspended by the scrubber bleed in a solids separator (192, 592, 692), conveying the scrubber bleed from the solids separator (192, 592, 692) into an evaporation vessel (194, 594, 694) and concentrating the scrubber bleed in the evaporation vessel (194, 594, 694) to produce hydrochloric acid vapor having a concentration of 5-22 wt-%. A corresponding system is also provided.

The present invention relates to a process for the separation of strong acid from its salts. In said process, a strong acid salt is reacted with organic weak base (OWB) in the presence of a hydrophilic solvent and CO.sub.2. The cation of the strong acid salt is precipitated to produce a carbonate/bicarbonate salt and the strong acid form a liquid salt with the OWB. The above process is performed in a solution comprising both the strong acid salt and the WBO. In the next step, the strong acid is released from its OWB liquid salt and the OWB is returned to a previous step.

Processes are provided which pyrolytically extract hydrochloric acid from a magnesium ion-rich salt mixture. In this regard, a supply of the magnesium ion-rich salt mixture (e.g., bittern) may be directed to a pyrolytic chamber where it is contacted with heated gas (e.g., combustion flue gas) at a sufficient temperature and for a sufficient time to form a vapor product stream comprised of hydrochloric acid and an insoluble pyrolyzed mixed salt stream comprised of magnesium hydroxide and sodium sulfate decahydrate. The solid pyrolyzed mixed salt stream may be separated into separate product streams comprising the insoluble magnesium hydroxide and remaining soluble salt fractions, while the vapor product stream of hydrochloric acid from the pyrolytic chamber may be condensed form an aqueous HCl solution. The magnesium ion rich salt mixture may be dehydrated prior to pyrolysis to achieve magnesium ions in a tetrahydrate state or lower (e.g., a monohydrate to a trihydrate state).

The invention relates to an improved process for making available the coproduct hydrogen chloride obtained in the preparation of an isocyanate by phosgenation of the corresponding amine for a desired subsequent use (i.e. a chemical reaction), in which part of the total hydrogen chloride obtained is isolated in gaseous form at a pressure which is higher than the pressure desired for the subsequent use of the hydrogen chloride by lowering the pressure of the crude product from the phosgenation and the remaining part of the total hydrogen chloride obtained is separated off at a pressure lower than that desired for the subsequent use from the liquid crude product from the phosgenation remaining after lowering of the pressure and is subsequently compressed to a pressure which is higher than that desired for the subsequent use, and in which the two hydrogen chloride streams obtained in this way are, preferably together after having been combined, purified so as to give a purified hydrogen chloride at a pressure which is higher than the pressure desired for the subsequent use.