US 2023/0016848 A1Published application

Method of cleaning an apparatus used in the concentration of a mineral acid

AssigneeCovestro Intellectual Property GmbH & Co. KG

InventorsBernd Pennemann, Kameh Tajvidi

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Abstract

The present invention relates to a method for preparing an apparatus (or a plant comprising a plurality of apparatuses), for example a heat exchanger, a vaporizer or a distillation column, for use in a process (in particular a continuously operated process) for concentrating a mineral acid by evaporation of water, wherein the apparatus or the plant comprises (at least) a device which is resistant to the mineral acid and the device is flushed with an aqueous alkali metal hydroxide solution having a concentration by mass of alkali metal hydroxide in the range from 1% to 30% at a temperature in the range from 40° C. to 90° C. for a time of from 2 hours to 7 days.

Claims15

Dependent claims

A method for preparing an apparatus for use in a process for concentrating a mineral acid by evaporation of water, wherein the apparatus comprises a device which is resistant to the mineral acid,

wherein the device has a coating comprising steel enamel, silicon carbide, glass, tantalum, niobium, a perfluorinated polymer, or a composite of two or more thereof,
or
wherein the device is made of one of steel enamel, silicon carbide, glass, tantalum, niobium, a perfluorinated polymer, or a composite of two or more thereof,
the method comprising flushing the device with an aqueous alkali metal hydroxide solution having a concentration by mass of alkali metal hydroxide in the range from 1% to 30% at a temperature in the range from 40° C. to 90° C. for a time of from 2 hours to 7 days.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 17/783,375Filed 16 Dec 2020
Priority: EP 19217596.618 Dec 2019
Published: 19 Jan 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification19 codes

C01B 17/88
Sulfur trioxide; Sulfuric acid: concentration of sulfuric acid
B01B 1/005
Boiling; Boiling apparatus for physical or chemical purposes ; Evaporation in general: evaporation for physical or chemical purposes; Evaporation…
B01D 3/148
By two or more of a fractionation, separation or rectification step: in combination with at least one evaporator
B01D 53/263
Drying gases or vapours: by absorption

Family

US 12,441,614 B2Related patent
US 2023/0016848 A1This patent

From the US filing history. Foreign family members aren’t listed.

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