Abstract: The present invention relates to a method for operating a plant for continuous production of an isocyanate by converting a primary amine A with phosgene P whilst maintaining, based on the amino groups of the primary amine, a stoichiometric excess of phosgene in the presence of a solvent L in the liquid phase, using a first, adiabatically operated reaction chamber and a second, isothermally operated reaction chamber. The method is characterised in that a combination of measures, in particular the maintenance of a sufficiently high starting pressure and a sufficiently high starting temperature, is applied in order to bring the plant back into the target state, standard operation, starting from a state of interruption to production.

Abstract: The invention relates to a method for producing di- and polyisocyanates of the diphenylmethane series, in which (i) the liquid product flow created in the phosgenation, (ii) the reaction mixture present in an optionally provided reactor for carbamic acid chloride cleaving, (ii) the liquid product flow leaving such an optionally provided reactor for carbamic acid chloride cleaving, (iv) the reaction mixture present in the dephosgenation, or (v) the liquid product flow created in the dephosgenation, is treated with a gaseous hydrogen chloride flow in one stage in a bubble column or in a plate column within a contact time of 1 min to less than 30 min. The product flow treated din this way or in the reaction mixture treated in this way is fed directly (i.e. in particular without further treatment with an inert gas) to the next step of the reaction or workup.

Abstract: The invention relates to a method for operating a production plant for producing a chemical product (1) by reacting a H-functional reactant (2) with phosgene (3) during an interruption in production when taking at least one plant part of the production plant out of operation, wherein low-oxygen and oxygen-rich phosgene-containing exhaust gas flows are directed separately from one another in different phosgene decomposition directions and separately from one another—at spatially different points—into a combustion device, wherein plant parts that have not been taken out of operation are operated in a closed-circuit operating mode. The invention also relates to a production plant for producing a chemical product by reacting H-functional reactants with phosgene, which is suitable for being operated with the method according to the invention.

Abstract: The invention relates to a method for operating a production plant for producing a chemical product (1) by reacting a H-functional reactant (2) with phosgene (3) during an interruption in production when taking at least one plant part of the production plant out of operation, wherein low-oxygen and oxygen-rich phosgene-containing exhaust gas flows are directed separately from one another in different phosgene decomposition directions and separately from one another—at spatially different points—into a combustion device, wherein plant parts that have not been taken out of operation are operated in a closed-circuit operating mode. The invention also relates to a production plant for producing a chemical product by reacting H-functional reactants with phosgene, which is suitable for being operated with the method according to the invention.

Abstract: The present invention relates to a process for preparing an isocyanate by reacting a primary amine with phosgene, comprising I) providing an amine solution, II) providing a phosgene solution, III) mixing the amine solution with the phosgene solution in a mixing unit, followed by IV) further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, V) expanding the remaining liquid phase in two or three stages, VI) further conversion of the liquid phase remaining after the last expansion stage in an indirectly heated reaction zone and VII) isolating the isocyanate from the reaction solution obtained therein.

Abstract: A process for preparing an isocyanate by reacting a primary amine with phosgene. The process includes providing an amine solution and adjusting its temperature in a heat exchanger, providing a phosgene solution and adjusting its temperature in a heat exchanger, mixing the amine solution with the phosgene solution, further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, expanding the remaining liquid phase, further conversion of the liquid phase remaining after expansion in an indirectly heated reaction zone, and isolating the isocyanate from the obtained reaction solution. The temperature in the reaction zone and the temperature in the separation zone is adjusted by fixing a target value of 110° C. to 145° C.

Abstract: The present invention relates to a process for preparing an isocyanate by reacting a primary amine with phosgene, comprising I) providing an amine solution, II) providing a phosgene solution, III) mixing the amine solution with the phosgene solution in a mixing unit, followed by IV) further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, V) expanding the remaining liquid phase in two or three stages, VI) further conversion of the liquid phase remaining after the last expansion stage in an indirectly heated reaction zone and VII) isolating the isocyanate from the reaction solution obtained therein.

Abstract: The present invention relates to a process for preparing an isocyanate by reacting a primary amine with phosgene, comprising I) providing an amine solution and adjusting its temperature in a heat exchanger, II) providing a phosgene solution and adjusting its temperature in a heat exchanger, III) mixing the amine solution with the phosgene solution in a mixing unit, followed by IV) further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, V) expanding the remaining liquid phase, VI) further conversion of the liquid phase remaining after expansion in an indirectly heated reaction zone and VII) isolating the isocyanate from the reaction solution obtained therein, in which the temperature in the reaction zone and separation zone is adjusted by fixing a target value within a range from 110° C. to 145° C.

Abstract: The present invention relates to a process for producing isocyanates in process chains, each of which produce an isocyanate end product via at least one intermediate product, wherein the heat energy liberated in a first production plant in a heat-emitting operation of producing an intermediate product, an isocyanate end product or a catalyst required for a substep of the process chain (first chemical product) is at least partly utilized for generating vapour, in particular water vapour, having a pressure of 1.31 bar(abs.) to 1.91 bar(abs.) and a temperature of 107° C. to 119° C. and the thus generated vapour is employed for performing a heat-consuming operation in the preparation of another chemical product (second chemical product) in a second production plant.

Abstract: The invention relates to a method for an economically and technically improved embodiment of a production interruption in a production method for isocyanates by phosgenation of the corresponding amines, in which the entire production plant is not closed while one or more parts of the plant is taken out of operation, rather the input materials and/or reaction products available in the production plant are recirculated through at least one part of the plant that has not been taken out of operation. The invention further relates to a plant for producing isocyanates and to a method for operating a plant for producing isocyanates.

Abstract: The invention relates to a method for producing isocyanates, according to which exhaust flows provided for the combustion are guided through an adsorption device before being supplied into the exhaust gas combustion process, and are thereby depleted of solvent, the adsorption device comprising at least two adsorption units connected in parallel, which are alternately (i) exposed to the at least one exhaust flow and (ii) regenerated with water vapor, where, during method step (i), an exhaust flow depleted of solvent is obtained, and during method step (ii), a flow containing water and solvent is obtained, the solvent proportion of which is recycled into a method for producing isocyanates.

Abstract: The invention relates to a method for producing isocyanates, according to which exhaust flows provided for the combustion are guided through an adsorption device before being supplied into the exhaust gas combustion process, and are thereby depleted of solvent, the adsorption device comprising at least two adsorption units connected in parallel, which are alternately (i) exposed to the at least one exhaust flow and (ii) regenerated with water vapour, where, during method step (i), an exhaust flow depleted of solvent is obtained, and during method step (ii), a flow containing water and solvent is obtained, the solvent proportion of which is recycled into a method for producing isocyanates.

Abstract: The present invention relates to a process for producing isocyanates in process chains, each of which produce an isocyanate end product via at least one intermediate product, wherein the heat energy liberated in a first production plant in a heat-emitting operation of producing an intermediate product, an isocyanate end product or a catalyst required for a substep of the process chain (first chemical product) is at least partly utilized for generating vapour, in particular water vapour, having a pressure of 1.31 bar(abs.) to 1.91 bar(abs.) and a temperature of 107° C. to 119° C. and the thus generated vapour is employed for performing a heat-consuming operation in the preparation of another chemical product (second chemical product) in a second production plant.

Abstract: A divided wall column includes: a column shell; a divided wall provided vertically inside the column shell, defining a divided wall section between an upper edge and a lower edge of the divided wall; and a liquid distributor provided within the divided wall section. The liquid distributor is fixed only to the column shell but not to the divided wall. By using the divided wall column, a defect involved in conventional divided wall columns, i.e. a maldistribution of fluid over mass transfer elements caused by a manufacturing defect of the divided wall resulted from its manufacturing process and/or a deformation thereof under operation conditions, can be minimized or even avoided.

Abstract: The invention relates to a method for an economically and technically improved embodiment of a production interruption in a production method for isocyanates by phosgenation of the corresponding amines, in which the entire production plant is not closed while one or more parts of the plant is taken out of operation, rather the input materials and/or reaction products available in the production plant are recirculated through at least one part of the plant that has not been taken out of operation. The invention further relates to a plant for producing isocyanates and to a method for operating a plant for producing isocyanates.

Abstract: Disclosed is a divided wall column, comprising: a column shell; a divided wall provided vertically inside the column shell, defining a divided wall section between an upper edge and a lower edge of the divided wall; and a liquid distributor provided within the divided wall section, characterized in that, the liquid distributor is fixed only to the column shell but not to the divided wall. By using the divided wall column of the present invention, a defect involved in conventional divided wall columns, i.e. a maldistribution of fluid over mass transfer elements caused by a manufacturing defect of the divided wall resulted from its manufacturing process and/or a deformation thereof under operation conditions, can be minimized or even avoided.