Hoechst Aktiengesellschaft

Wolfgang Opitz

Hans Hennen

Otto Buhring

Hydrochloric acid having a substantially constant HCl content of 20 to 36% is produced continuously by removing hydrogen chloride from hot combustion gas. To this end, hot combustion gas containing 1 to 10% by volume of HCl and steam, this gas being obtained by the joint combustion of off-gases containing chlorinated hydrocarbons and liquid residues of chlorinated hydrocarbons, is introduced into a quenching zone, and quenched therein, down to a temperature lower than its dew point, by means of cooled hydrochloric acid containing hydrogen chloride in a concentration of 20 to 36%, which concentration corresponds to the concentration of the hydrochloric acid which is to be produced. The resulting gas-liquid mixture is separated in an absorption cooling zone into cooled hydrochloric acid and cooled combustion gas containing 0.1 to 1% by volume of HCl. The cooled hydrochloric acid is introduced into a reservoir zone capable of receiving a multiple of the quantity of hydrochloric acid produced per hour, and recycled from the said reservoir zone to the quenching zone. Additional 20 to 36% hydrochloric acid produced is taken out of the quenching cycle.

Production of hydrochloric acid by removing hydrogen chloride from

A cooling device for use in the quenching of combustion gases containing hydrogen chloride. The device is an elongated steel vessel with angularly spaced openings to receive nozzles for the injection of a quenching liquid. The vessel contains a hard rubber layer extending over its inner surface and an acid-resistant ceramic lining within the hard rubber layer.

Cooling device

Off-gases and liquid residues containing chlorinated hydrocarbons, are subjected to joint combustion by forming a mist comprising a mixture of off-gases and atomized liquid residues, the latter being atomized by means of air and/or steam, and directing this mist into a preheated combustion chamber lined with refractory bricks. The mixture is introduced into the combustion chamber jointly with combustion air through a burner having four feed pipes arranged coaxially with respect to each other and terminating in conically tapered outlets, the three outer feed pipes defining three separate and coaxial annular zones around the innermost feed pipe. The liquid residue fed in and burnt is used in a quantity sufficient to maintain in the combustion chamber a predetermined maximum temperature which is not above the range 1200.degree. to 1800.degree. C., and which is compatible with the refractory properties of the brick lining of the combustion chamber. The resulting hot combustion gases are withdrawn from the combustion chamber, quenched with water, and hydrochloric acid is recovered from the resulting aqueous solution.

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Hurth, Germany

Wolfgang Opitz