Safe production of chlorine dioxide in a pressurized gaseous state
AssigneeQuantum Technologies, Inc.
InventorsRobert E. Yant, Thomas S. Sturik
Life of this patent
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Abstract
A safe continuous process is disclosed for generating superatmospheric pressure mixtures of chlorine and chlorine dioxide, wherein the chlorine dioxide is generated in situ by chemically reducing inorganic chlorates in aqueous sulfuric acid solutions, and most of the chlorine is supplied from a high-pressure external source. The mixed gaseous products contain Cl.sub.2 and ClO.sub.2 in volumetric Cl.sub.2 /ClO.sub.2 ratios of at least 10/1, and preferably between about 11/1 and 99/1, and are ideally suited for direct use in various industrial treatments, notably in the purification and bleaching of wood pulp and the like.
Claims20
In a method of generating chlorine dioxide from inorganic chlorate by chemically reducing same in an aqueous solution of H.sub.2 SO.sub.4 having an acid normality of at least about 4, the improvement which comprises conducting said reducing reaction at a temperature of less than 100.degree. C. under a superatmospheric pressure of more than half an atmosphere in the absence of inert sweep gases while continuously feeding substantially pure, pressurized chlorine gas thereto in proportions to yield a superatmospheric pressurized effluent gaseous product at an absolute pressure of at least 1.5 atmospheres consisting essentially of a mixture of chlorine and chlorine dioxide in volumetric Cl.sub.2 /ClO.sub.2 ratios greater than about 10/1, enabling said gaseous product to be transferred directly to a continuous industrial process operating above atmospheric pressure.
In a process for generating mixtures of chlorine dioxide and chlorine by chemically reducing inorganic chlorate in an aqueous solution which is at least about 4 normal in sulfuric acid and which is supplied with chloride ion at a rate sufficient to provide a major portion of the chemical reducing agent serving to reduce said chlorate, the improvement which comprises conducting said process below about 80.degree. C. and at superatmospheric pressure of at least about 2 atmospheres absolute by continuously feeding substantially pure chlorine gas from high-pressure external source into intimate contact with said aqueous solution in volumetric proportions equal to between about 10 and about 99 times the rate of formation of chlorine idoxide from said chemical reduction reaction while excluding inert sweep gases and withdrawing as finished product at an absolute pressure of over 1.5 atmospheres a gaseous mixture having a volumetric Cl.sub.2 /ClO.sub.2 ratio of between about 11/1 and about 99/1, enabling it to be transmitted directly to a pressurized zone for treating wood pulp and introduced thereto under its own pressure.
Dependencies are inferred from the claim text.