High-pressure reactor for the synthesis of melamine

Patent metadata

Field	Value
Publication number	US-9850217-B2
Application number	US-201515123924-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Mar 12, 2014
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Reactor for the synthesis of melamine from urea, in accordance with the high-pressure non-catalytic process, comprising: a vertical reactor body ( 1 ), at least one inlet ( 2 ) for the urea melt, a set of heating elements ( 3 ), and a central duct ( 7 ), said set of heating elements ( 3 ) being arranged inside said central duct.

First claim

The invention claimed is:

1. A reactor for the synthesis of melamine from urea, according to a high-pressure non-catalytic process, comprising:
a vertical reactor body, at least one inlet for the urea melt, a set of heating elements, and a central duct, wherein:
said central duct delimits an inner reaction zone inside said duct, and a peripheral reaction zone around said duct, and said set of heating elements is arranged in the inner reaction zone inside said central duct.

2. The reactor according to claim 1 , characterized by comprising no heating element inside said peripheral reaction zone.

3. The reactor according to claim 1 , wherein said inlet for the urea melt is connected to a distributor configured to introduce urea into said peripheral reaction zone.

4. The reactor according to claim 3 , said distributor being extended around the central duct and comprising urea delivery means which are arranged to introduce urea in a substantially uniform manner and with axial symmetry into said peripheral reaction zone.

5. The reactor according to claim 4 , wherein said distributor has a substantially toroidal form.

6. The reactor according to claim 1 , wherein a lower end of said central duct is distanced from a base of the set of heating elements, thus defining a liquid recirculation passage between the inner reaction zone and the surrounding peripheral reaction zone.

7. The reactor according to claim 1 , wherein said central duct extends, inside the reactor, up to a height lower than the height of the heating elements.

8. The reactor according to claim 1 , wherein said central duct is delimited by a substantially cylindrical shell.

9. The reactor according to claim 1 , wherein said set of heating elements is a bundle of tubes connected to a tube sheet at the bottom of the reactor.

10. The reactor according to claim 1 , wherein the urea inlet is at the base of the peripheral region and is arranged to feed urea with an upward flow, and a recirculation passage is provided at the base of the central duct, in such a way that the reactor operates with an ascending flow in the peripheral reaction zone and a descending flow in the central duct where the heating elements are installed.

11. The reactor according to claim 1 , comprising a deflector which is in the form of circular crown and is located at the top of said peripheral reaction zone, said deflector being preferably flat or frusto-conical.

12. The reactor according to claim 11 , comprising a header for collecting the melamine, said header being associated with said deflector and configured to collect melamine in a distributed manner along a circumference.

Assignees

• Casale Sa

Inventors

• Rizzi Enrico

Classifications

• B01J19/246

  internally, i.e. the mixture circulating inside the vessel such that the upward stream is separated physically from the downward stream(s) · CPC title

• B01J3/04

  Pressure vessels, e.g. autoclaves · CPC title

• B01J2219/00081

  Tubes · CPC title

• B01J2219/00078

  Fingers · CPC title

• B01J4/002

  Nozzle-type elements (nozzle-type reactors B01J19/26) · CPC title