Bayer Corporation

Haarmann & Reimer Gmbh

Hoarmann & Reimer Corp.

Chetna Patel

Steven W Felman

David J Solow

Bhalchandra H Patwardhan

The disclosed invention provides for two improved processes for recovering citric acid and other organic acids. The process for recovering citric acid from an impure process stream includes concentrating the impure process stream to obtain a concentrated solution of citric acid, adding a sufficient amount of a strong acid or salt to the solution in order to crystallize citric acid and separating the resulting citric acid crystals from the mother liquor. The useful strong acids or salts thereof are sulfuric acid, hydrochloric acid, sodium chloride, sodium sulfate and nitric acid. Also ion exchange resins may be utilized in order to recover additional yields of citric acid. Further, the impure process stream is obtained by a solvent extraction process or a lime and sulfuric acid process. The other useful process provided for by the invention includes recovering organic acid from an impure process stream, such as a fermentation broth. However, the acid is added to the impure process stream in the first step and then concentrating the resulting impure process stream to recover crystals from the concentrate thereof. This particular improved process is essentially one step purification without the waste disposal problems or large capital investment required by either the conventional lime/sulfuric or solvent extraction recovery processes.

Process for producing citric acid from an impure process stream

This invention provides an improved process of recovering organic acid from an impure process stream, such as a fermentation broth, by the addition of a strong acid or salt thereof to the impure process stream. The process provides for essentially one step purification without the waste disposal problems or large capital investment required by either the conventional lime/sulfuric or solvent extraction recovery processes. The recovery can be further improved by treating the mother liquor remaining after separation of the citric acid crystals to obtain an additional yield. The preferred strong acid is sulfuric acid and the preferred mother liquor treatment is passage through an ion exclusion resin column.

Recovery of organic acid from an impure process stream by addition of

This invention provides an improved method for recovering an organic acid as a salt from various process streams by addition of a crystallizing base to a concentrated solution of neutralized organic acid. The addition of such a base causes crystallization of the salt. This process provides more efficient recovery of organic acid salt from a fermentation process stream than traditional crystallization and it may be used essentially as a one step purification process. The improved method is particularly applicable to the recovery of trisodium or tripotassium citrate from process streams produced in the fermentation and recovery of citric acid, with the addition of a crystallizing base such as sodium hydroxide, sodium carbonate, potassium hydroxide, or ammonia. The resulting product may be combined with an anticaking agent and/or dried to provide a particularly free flowing product.

Recovery of organic acid salts from impure process streams by addition

This invention provides an improved method for recovering an organic acid as a salt from various process streams by addition of a crystallizing base to a concentrated solution of neutralized organic acid. The addition of such a base causes crystallization of the salt. This process provides more efficient recovery of organic acid salt from a fermentation process stream than traditional recrystallization and it may be used essentially as a one step purification process. The improved method is particularly applicable to the recovery of trisodium or tripotassium citrate from process streams produced in the fermentation and recovery of citric acid, with the addition of a crystallizing base such as sodium hydroxide, potassium hydroxide or ammonia.

Growing community of inventors

Elkhart, IN, United States of America

Chetna Patel