# US 2009/0260657 A1 · Method for cleaning deposits from equipment that have accumulated during a method for recovering nmp, by the introduction of hot water and agitation

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- Number: US 2009/0260657 A1
- Document ID: US20090260657A1
- Status: Published application
- Kind: A1
- Application number: 11/721,827
- Filed: 2005-12-08
- Published: 2009-10-22
- Earliest claimed: 2004-12-16
- Assignees: BASF SE
- Inventors: Aurelie Alemany; Maximilian Vicari; Tanja Kirchner; Frank Steglich
- Web page: https://patentgrep.com/patent/US20090260657A1

## CPC

- B08B 9/08: Cleaning containers, e.g. tanks
- B01J 19/18: Stationary reactors having moving elements inside (B01J19/08, B01J19/26 take precedence)
- C07D 207/267: with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to the ring nitrogen atom
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

A process is proposed for cleaning an apparatus to remove deposits from a process for the recovery of purified N-methylpyrrolidone (NMP) by evaporating NMP from a contaminated NMP stream which is obtained in a process for the extractive separation of acetylene from the reaction mixture of a partial oxidation of hydrocarbons after expulsion of the acetylene as a gas, wherein hot water is passed into the apparatus and is stirred.

## Claims

### Claim at position 1

-9. (canceled)

### Claim 10

A process for cleaning an apparatus to remove deposits from a process for the recovery of purified N-methylpyrrolidone (NMP) which comprises evaporating NMP from a contaminated NMP stream which is obtained in a process for the extractive separation of acetylene from the reaction mixture of a partial oxidation of hydrocarbons after expulsion of the acetylene as a gas, wherein hot water is passed into the apparatus and is stirred.

### Claim 11 (depends on 10)

The process according to claim 10, wherein the contaminated NMP stream from the process for the extractive separation of acetylene is passed into one or more preevaporation stages before being fed into the apparatus.

### Claim 12 (depends on 10)

The process according to claim 10, wherein the hot water is at a temperature in the range from 40 to 180° C.

### Claim 13 (depends on 10)

The process according to claim 10, wherein stirring is effected for at least 5 min.

### Claim 14 (depends on 10)

The process according to claim 10, comprising a layer thickness of the deposits of from 0.1 to 30 cm.

### Claim 15 (depends on 10)

The process according to claim 10, comprising a residual NMP content in the deposits of about 35% by weight.

### Claim 16 (depends on 10)

The process according to claim 10, wherein the volume of the water passed into the apparatus is from about two to 30 times the volume of the deposits.

### Claim 17 (depends on 10)

The process according to claim 10, wherein an aqueous solution comprising about 2% by weight of material of the deposits and about 2% by weight of NMP is taken off from the apparatus, and wherein the aqueous solution has a viscosity of from 1 to 5 mPa·s.

### Claim 18 (depends on 10)

The process according to claim 10, wherein the apparatus is a stirred kettle.

### Claim 19 (depends on 12)

The process according to claim 12, wherein the hot water is at a temperature in the range from 50 to 150° C.

### Claim 20 (depends on 19)

The process according to claim 19, wherein the hot water is at a temperature of about 90° C.

### Claim 21 (depends on 13)

The process according to claim 13, wherein stirring is effected from 5 min to 1 hr.

### Claim 22 (depends on 21)

The process according to claim 21, wherein stirring is effected about half an hour.

### Claim 23 (depends on 14)

The process according to claim 14, comprising a layer thickness of the deposits from 1 to 10 cm.

### Claim 24 (depends on 16)

The process according to claim 16, wherein the volume of the water passed into the apparatus is about 15 times the volume of the deposits.