• Introduction and Preliminary Process Description

     Fumaric Acid (FA) production plant starts with preparing Maleic Acid solution as a raw feed for final product. This can be an absorption unit in case of production from off gases or a disolving unit in case of production from maleic anhydride.

Following is the transformation unit - batch process which is further followed by dehydrating / refining and solidification Units which usually are continous processes.

• Maleic Anhydride Absorption

In the absorption system, maleic anhydride is absorbed into process water from the cooled reactor off-gas, which contains the MA.  When the gas containing maleic anhydride passes through the absorber and contacts water, the MA is converted into maleic acid, and the maleic acid solution (Mac) is formed. The MA-free gases leaving the MA Absorber are routed to the Incinerator for disposal.

In case of production from Maleic anhydride the Absorption Unit is replaced by Disolving Unit where maleic anhydride is dissolved to Maleic Acid solution.

• Maleic Anhydride Transformation

The Mac solution batch is charged to reactor at defined temperature. Catalysts are added into the reactor for increasing the reaction yield and reducing formation of by-products. Reaction takes place at a defined temperature, which is controlled by steam heating and air cooling inside of the reactor.

After the isomerization reaction the product slurry is cooled down and concentrated by vacuum. Under vacuum the fumaric acid slurry starts concentrating and forming crystals. 

• Concentrating, drying and packing

The fumaric acid slurry is fed to centrifuge, where cc. 80% of the water content is removed as filtrate. Centrifuge outlet can be loaded into big-bags and dispatched as „wet” fumaric acid product.

In case of dry fumaric acid production the concentrated „wet” fumaric acid is dried by a fluidized dryer operated with steam heated hot air. After the dryer the fumaric acid is supplied into a filtration / sizing system and further to storage in a silo, from where it is fed to the weighing and packing system.