Abstract: A method for purifying a crude aqueous lactic acid composition, the method includes heating and pressurizing the crude aqueous lactic acid composition so as to obtain a liquid, heated and pressurized crude aqueous lactic acid composition, flash evaporating the liquid, heated and pressurized crude aqueous lactic acid composition obtained so as to obtain crude lactic acid vapor, and gradually condensing the crude lactic acid vapor by leading the crude lactic acid vapor through at least three successive condensers so as to obtain at least three condensed streams, one stream of the at least three condensed streams being a purified lactic acid stream.

Abstract: A plant for preparing a purified isomeric methylene diphenyl diisocyanate monomer from a mixture of different isomeric monomers is disclosed herein. The plant can comprise a distillation apparatus, which comprises: a) a distillation column including a structured packing, b) a source for a mixture of different isomeric methylene diphenyl diisocyanate monomers, c) an evaporator, d) an overhead vapor condenser, e) optionally, an overhead vacuum system and f) a flow-controlled reflux system. The overhead vapor condenser comprises a shell and tube arrangement and is embodied so as to directly subcool the condensate to less than 47° C. The flow-controlled reflux system comprises a heater, which is embodied so as to reheat a partial stream of the condensate formed in the overhead vapor condenser up to 190° C.

Abstract: A plant for preparing a purified isomeric methylene diphenyl diisocyanate monomer from a mixture of different isomeric monomers is disclosed herein. The plant can comprise a distillation apparatus, which comprises: a) a distillation column including a structured packing, b) a source for a mixture of different isomeric methylene diphenyl diisocyanate monomers, c) an evaporator, d) an overhead vapor condenser, e) optionally, an overhead vacuum system and f) a flow-controlled reflux system. The overhead vapor condenser comprises a shell and tube arrangement and is embodied so as to directly subcool the condensate to less than 47° C. The flow-controlled reflux system comprises a heater, which is embodied so as to reheat a partial stream of the condensate formed in the overhead vapor condenser up to 190° C.

Abstract: The present invention relates to a method for purifying a crude benzoic acid (32) containing 5 to 20% by weight of byproducts and 80 to 95% by weight of benzoic acid, by means of distillation, wherein the distillation is performed in a plant comprising a first distillation system (54), which comprises a divided wall column (10).

Abstract: The present invention relates to a method for purifying a crude benzoic acid (32) containing 5 to 20% by weight of byproducts and 80 to 95% by weight of benzoic acid, by means of distillation, wherein the distillation is performed in a plant comprising a first distillation system (54), which comprises a divided wall column (10).

Abstract: The apparatus for the esterification of a fatty acid F includes a column with a packing. In addition to functioning as a catalytic reactor, the packing functions as a stripping section. A heteregenous catalysis of a fatty acid is carried out with an alcohol used in the same molar ratio or in excess. A gaseous alcohol-rich counter-flow is produced in a sump of the column by vaporization. Water is removed from the reaction zone by means of the counter-flow acting as a stripping gas. The loaded stripping gas is at least partially liquefied at the head of the column. The head product is separated into a water-rich fraction as well as an alcohol-rich fraction. The alcohol-rich fraction is returned to the process as a starting material for the esterification and for the production of the stripping gas.

Abstract: The PLANT for the esterification of a fatty acid F includes a column with a packing. In addition to functioning as a catalytic reactor, the packing functions as a stripping section. A heteregenous catalysis of a fatty acid is carried out with an alcohol used in the same molar ratio or in excess. A gaseous alcohol-rich counter-flow is produced in a sump of the column by vaporisation. Water is removed from the reaction zone by means of the counter-flow acting as a stripping gas. The loaded stripping gas is at least partially liquefied at the head of the column. The head product is separated into a water-rich fraction as well as an alcohol-rich fraction. The alcohol-rich fraction is returned to the process as a starting material for the esterification and for the production of the stripping gas.

Abstract: The method for the esterification of a fatty acid F is carried out in a column with a packing. In addition to functioning as a catalytic reactor, the packing functions as a stripping section. A heteregenous catalysis of a fatty acid is carried out with an alcohol used in the same molar ratio or in excess. A gaseous alcohol-rich counter-flow is produced in a sump of the column by vaporization. Water is removed from the reaction zone by means of the counter-flow acting as a stripping gas. The loaded stripping gas is at least partially liquefied at the head of the column. The head product is separated into a water-rich fraction as well as an alcohol-rich fraction. The alcohol-rich fraction is returned to the process as a starting material for the esterification and for the production of the stripping gas.

Abstract: The method for the esterification of a fatty acid F is carried out in a column with a packing. In addition to functioning as a catalytic reactor, the packing functions as a stripping section. A heteregenous catalysis of a fatty acid is carried out with an alcohol used in the same molar ratio or in excess. A gaseous alcohol-rich counter-flow is produced in a sump of the column by vaporisation. Water is removed from the reaction zone by means of the counter-flow acting as a stripping gas. The loaded stripping gas is at least partially liquefied at the head of the column. The head product is separated into a water-rich fraction as well as an alcohol-rich fraction. The alcohol-rich fraction is returned to the process as a starting material for the esterification and for the production of the stripping gas.