Methods for producing chemical products with operation interruptions

Patent metadata

Field	Value
Publication number	US-10513487-B2
Application number	US-201515320807-A
Country	US
Kind code	B2
Filing date	Jun 22, 2015
Priority date	Jun 24, 2014
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

This invention relates to methods for producing chemical products, wherein the one or more feed materials are reacted to form a chemical product or a chemical composition. The invention further relates to plants for performing such methods, said plants being designed in such a way that, during an interruption of the methods, no input of at least one feed material into the reaction occurs and the plant parts not affected by a revision measure, maintenance measure, repair measure, or cleaning measure are operated in so-called re-circulation mode. It is thereby achieved, among other things, that only the affected plant part needs to be shut down for the time of the measure, which can be advantageous with regard to the productivity and economy of the method and the quality of the produced products. Finally, the invention relates to methods for operating plants in the event that individual plant parts are taken out of service.

First claim

The invention claimed is:

1. A process for preparing a chemical product or a chemical composition, comprising:
(I) reacting at least one substrate in a reactor to form a polyphasic reaction mixture comprising at least one chemical product or a chemical composition, in which the mass flow of said at least one substrate being introduced into the reactor is m 1 , wherein the reactor may be part of a reactor line in which two or more reactors are operated in parallel;
(II) working up the polyphasic reaction mixture obtained in step (I) in a workup apparatus to obtain a crude product, which is an organic phase comprising the desired chemical product or chemical composition, and at least one secondary stream, which is an aqueous phase and/or a gas phase that is separated from the crude product;
(III) optionally, purifying the crude product obtained in step (II) in at least one purifying apparatus, in which at least one secondary stream is removed to obtain a purified end product alongside the at least one secondary stream removed from the purified end product;
(IV) optionally, working up the at least one secondary stream obtained in step (II) in a workup unit;
and
(V) if (III) is performed, optionally working up the at least one secondary stream obtained in step (III) in a workup unit,
comprising shutting down one or more plant sections from (I) to (V), including interrupting the formation of further chemical product or further product composition by reducing the mass flow m 1 in (I) to zero and stopping said one or more plant sections, conducting an inspection, repair, maintenance or cleaning measure in said one or more plant sections that have been shut down, and, operating at least one of the plant sections that has not been shut down in circulation mode in which an output stream of said at least one plant section operating in circulation mode is used as an input stream for said at least one plant section operating in circulation mode or an upstream plant section that has not been shut down.

2. The process as claimed in claim 1 , comprising (I) to (III).

3. The process as claimed in claim 2 , additionally comprising (IV) and (V).

4. The process as claimed in claim 3 , wherein every plant section that has not been shut down is operated in circulation mode.

5. The process as claimed in claim 1 , wherein at least two substrates are reacted in the reactor from (I) and the second substrate is introduced into the reactor from (I) with a mass flow m 2 .

6. The process as claimed in claim 1 , further comprising (Ia), wherein at least one third substrate is reacted with the product of the reaction from (I) in the reactor from (I) or in a further reactor, and the at least one third substrate is introduced into the at least one reactor from (Ia) with a mass flow m 3 .

7. The process as claimed in claim 1 , wherein the chemical product is a polycarbonate or one of its precursors, an isocyanate or one of its precursors, an active pharmaceutical ingredient, an olefin, aromatic or polyolefin.

8. A method of operating a plant for preparing a chemical product or a product composition during a shutdown of the preparation process, in which the plant comprises plant sections of:
(I) a reactor for converting at least one substrate to a polyphasic product mixture comprising the desired chemical product or product composition, wherein the reactor may be part of a reactor line in which two or more reactors are operated in parallel,
(II) a workup apparatus for obtaining a crude product, which is an organic phase comprising the desired chemical product or chemical composition, from the polyphasic product mixture obtained in said reactor alongside at least one secondary stream, which is an aqueous phase and/or a gas phase separated from the crude product,
(III) optionally, a purifying apparatus for purifying the crude product obtained in said workup apparatus to give a purified end product with removal of at least one secondary stream separated from the purified end product,
(IV) optionally, a workup unit for workup of the at least one secondary stream obtained in said workup apparatus,
and
(V) if the purifying apparatus is present, optionally a workup unit for workup of the at least one secondary stream obtained in said purifying apparatus,
wherein the method comprises:
(i) interrupting the formation of further chemical product or further product composition by stopping the supply of said at least one substrate into any reactor (I),
(ii) operating at least one of the plant sections in circulation mode, in which an output stream of said at feast one plant section operating in circulation mode is used as an input stream for said at least one plant section operating in circulation mode or as an input steam for an upstream plant section;
and
(iii) shutting down at least one of the plant sections (I) through (V) that is not operating in circulation mode by stoppage of said plant section that is not operating in circular mode and conducting an inspection, repair, maintenance or cleaning measure in said plant section.

9. The method as claimed in claim 8 , further comprising:
(iv) optionally opening the at least one plant section shut down in (iii);
(v) performing a maintenance, cleaning, inspection and/or repair measure in the plant section shut down in (iii);
(vi) if (iv) is performed, closing and optionally inertizing the at least one plant section from (v);
(vii) starting up the at least one plant section from (vi);
and
(viii) starting the supply of the at least one substrate to the reactor (I).

Assignees

• Covestro Deutschland Ag

Inventors

• Knauf Thomas
• Drinda Peter
• Wershofen Stefan
• Gruner Klaus-Gerd
• Hartjes Volker

Classifications

• C07C205/06

  having nitro groups bound to carbon atoms of six-membered aromatic rings · CPC title

• B01J2219/00033

  Continuous processes · CPC title

• B01J2208/00716

  Means for reactor start-up · CPC title

• B01J2208/00646

  Means for starting up the reaction · CPC title

• B01J2208/00637

  Means for stopping or slowing down the reaction · CPC title