Certains contenus de cette application ne sont pas disponibles pour le moment.
Si cette situation persiste, veuillez nous contacter àObservations et contact
1. (WO2019048371) PROCÉDÉ DE NETTOYAGE D'UNE PLAQUETTE DE SEMI-CONDUCTEURS
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

Claims:

1. Method for cleaning a phosgene-conducting apparatus which has at least one feed conduit which can be shut off and at least one discharge conduit which can be shut off, comprising the steps:

a) lowering the pressure in the apparatus to be cleaned to a value of less than or equal

b) shutting off all conduits connected to the apparatus to be cleaned with the exception of at least one feed conduit for gaseous ammonia;

c) introducing gaseous ammonia from an ammonia gas source through the at least one feed conduit which has not been shut off until a predetermined pressure of greater than or equal to 1.01 bar(abs.) has built up in the apparatus to be cleaned;

d) measuring the pressure in the apparatus to be cleaned, continuously or at intervals of at most 1 hour, and, as soon as the pressure drops by more than 5.0% below the predetermined value, bringing the pressure back to the predetermined value or to a value deviating at most + 2.0% from the predetermined value by introducing further gaseous ammonia;

e) as soon as the pressure in the apparatus to be cleaned remains in a fluctuation range of + 5.0% around the predetermined value, for a period of more than 1.0 hour, separating the ammonia gas source from the apparatus to be cleaned, optionally, lowering the pressue in the apparatus, releasing the shutting-off of at least one discharge conduit, followed by passing an inert gas through the apparatus to be cleaned.

2. Method according to Claim 1, wherein step a) is preceded by the following step:

aa) passing carbon monoxide through the apparatus to be cleaned.

3. Method according to Claim 1 or 2, in particular according to Claim 2, wherein the following step:

ab) passing an inert gas through the apparatus to be cleaned,

is carried out before step a), in particular, when step aa) is carried out, after step aa) and before step a).

Method according to any of Claims 1 to 3, wherein the apparatus to be cleaned is brought to a temperature in the range from 60.0°C to 140.0°C during step aa), if carried out, and/or during step ab), if carried out, and/or during step a).

Method according to any of the preceding claims, wherein the apparatus to be cleaned is brought to a temperature in the range from 50.0°C to 80.0°C during steps c) and d).

Method according to any of the preceding claims, wherein step e) is followed by:

f) passing an aqueous stream, in particular passing water or aqueous ammonia, through the apparatus to be cleaned, followed by drying by passing air or an inert gas through.

Method according to any of Claims 1 to 5, wherein the apparatus to be cleaned is, after step e), either opened or taken into operation without an aqueous stream being passed through the apparatus to be cleaned before opening or taking into operation.

8. Method according to any of the preceding claims, wherein the apparatus to be cleaned is selected from among

• reactors for preparing phosgene,

• reactors for reacting phosgene with a reactive starting material,

• work-up apparatuses for purifying products which have been produced using phosgene and

• peripheral equipment such as, in particular, pipes and containers.

9. Method according to Claim 8, wherein the apparatus to be cleaned is a reactor filled with activated carbon suitable for preparing phosgene from carbon monoxide and chlorine.

Method according to Claim 9, wherein the reactor filled with activated carbon suitable for preparing phosgene from carbon monoxide and chlorine is part of a production plant for preparing a chemical product by reacting a phosgene -reactive starting material with phosgene.

Method according to Claim 10, wherein the phosgene-reactive starting material is compound having two or more phenolic hydroxy groups or a compound having two more primary amino groups.

Method according to either Claim 10 or 11, wherein the production plant for preparing a chemical product has n reactors suitable for preparing phosgene from carbon monoxide and chlorine which are filled with activated carbon and can be regulated independently of one another, where n is a natural number from 2 to 10, with phosgene being prepared from carbon monoxide and chlorine in m reactors, where m is a natural number in the range from 1 to n - 1, while the cleaning steps aa), optionally ab), and a) to e) are carried out in at least one reactor.

Method according to any of Claims 2 to 12, wherein step aa) is carried out and the carbon monoxide-containing gas leaving the apparatus to be cleaned in step aa) is fed to a process for preparing phosgene from carbon monoxide and chlorine.

14. Method according to any of Claims 9 to 13, wherein step e) or, if carried out, step f) is followed by the following step:

g) the activated carbon is removed and replaced by fresh activated carbon.

Method according to any of the preceding claims, wherein the predetermined pressure step c) is in the range from 1.02 bar(abs.) to 4.00 bar(abs ).