Distributor device, in particular for falling film evaporators, and use thereof

Patent metadata

Field	Value
Publication number	US-10894222-B2
Application number	US-201816485492-A
Country	US
Kind code	B2
Filing date	Feb 12, 2018
Priority date	Feb 14, 2017
Publication date	Jan 19, 2021
Grant date	Jan 19, 2021

Abstract

The present invention relates to a distributor device (10000) for the even distribution of a fluid (10) into 2 or more fluid streams each containing gas (11) and liquid (12), with a falling film evaporator (100000), in which the distributor device according to the invention serves to distribute the 2 or more fluid streams onto the heating pipes of the evaporator, and to the use of the distributor device (10000) according to the invention and in particular the falling film evaporator (100000) according to the invention in the production and/or preparation of chemical products. The distributor device according to the invention is characterized, in particular, by a swirl breaker (600) for the gas phase (11) which arises from separating the fluid (10) into a gas phase (11) and a liquid phase (12) within the distributor device.

First claim

The invention claimed is:

1. A device suitable for uniform division of a fluid into n fluid streams each containing gas and liquid, where n is a natural number greater than or equal to 2 , the device comprising:
(a) an upright cap bounded at the bottom by a plate;
(b) an entry port arranged in a lateral delimiting wall of the upright cap, the entry port configured to bring about tangential inflow of the fluid entering therein;
(c) an internal arranged upright in the interior of the cap, wherein the internal:
(i) together with the interior wall of the cap, forms an annular gap for downflowing liquid,
(ii) comprises an upper edge that ends above the entry port and below an upper delimitation of the upright cap so that the upper edge of the internal and the upper delimitation of the cap form a passage for downward-flowing gas,
(iii) has, at the top thereof, at least one upper opening for the downward-flowing gas flowing therein,
(iv) comprises a lower edge that ends above the plate so that the lower edge of the internal and the plate form a passage for the downflowing liquid, and
(v) comprises at least one opening at the bottom thereof that is hydrodynamically connected to the at least one upper opening; and

(d) n guide devices, wherein the guide devices protrude through the at least one opening at the bottom of the internal into the internal and the guide devices comprise liquid entry openings and gas entry openings;
wherein a swirl breaker for the downward-flowing gas stream is arranged in the interior of the internal, the swirl breaker being configured to reduce or eliminate turbulence in the downward-flowing gas stream and to reduce the rotational energy of downward-flowing gas stream.

2. The device of claim 1 , wherein the internal has a cross section that widens in a downward direction.

3. The device of claim 1 , wherein a swirl breaker for liquid having through-openings is arranged in the annular gap below the entry port, the through-openings being configured to allow flow of the downflowing liquid therethrough .

4. The device of claim 3 , wherein the swirl breaker for liquid is a metal plate in which the through-openings are formed by at least two holes distributed uniformly over the entire area of the plate and/or by at least one slit that runs through the entire area of the plate.

5. The device of claim 1 , wherein the at least one upper opening extends over the entire internal cross section of the internal and/or the at least one opening through which the n guide devices protrude into the internal extends over the entire internal cross section of the internal.

6. The device of claim 1 , wherein then guide devices are tube spouts or constituents of tubes.

7. The device of claim 6 , wherein the liquid entry openings:
(i) are tangential slits arranged so that the flow of the downflowing liquid produced on the inside of the guide devices has the same direction as the flow of the downflowing liquid produced in the annular gap by the arrangement of the entry port, or
(ii) are axial slits.

8. The device of claim 1 , wherein the swirl breaker for the downward-flowing gas stream is selected from the group consisting of a swirl cross, a packing, a knitted wire mesh, a perforated plate, and a deflection plate.

9. The device of claim 1 , wherein the n guide devices protrude to a height in the range from 10 mm to 100 mm into the internal.

10. A falling film evaporator comprising:
(a) an outer, enclosing shell,
(b) n tubes fastened in an upper tube plate and a lower tube plate, where n is a natural number greater than or equal to 2, configured so that on the inside of which a liquid film can flow down,
(c) an upper distributor device configured to distribute liquid and gas into the individual tubes,
(d) a feed device configured to feed a heating medium into a tube exterior space formed by the outside of the tubes and the shell,
(e) a discharge device configured to discharge cooled heating medium from the tube exterior space,
(f) a vapor offtake device configured to offtake vapor,
(g) a liquid offtake device configured to offtake residual liquid not vaporized inside the tubes, and
(h) a device configured to separate and collect the residual liquid and the vapor, wherein the upper distributor device is the device of claim 1 , where the bottom of the device forms the upper tube plate of the falling film evaporator and then guide devices are joined to the n tubes at the upper end thereof or the n guide devices are constituents of the n tubes.

11. The falling film evaporator of claim 10 , further comprising a return device configured to recirculate part of the residual liquid into the distributor device, where the return device:
(i) comprises a mixing device configured to mix the recirculated part of the residual liquid with the fluid before entry into the distributor device, or (ii) opens into an entry port that is different from the entry port and is arranged in a lateral delimiting wall of the cap.

12. A process for producing and/or working-up of a chemical product selected from the group consisting of organic nitro compounds, organic primary amines, isocyanates, polyether polyols and polycarbonates, comprising using the device of claim 1 .

13. A process for producing and/or working-up of a chemical product selected from the group consisting of organic nitro compounds, organic primary amines, isocyanates, polyether polyols and polycarbonates, comprising using the falling film evaporator of claim 10 .

14. The process of claim 13 , comprising using the falling film evaporator in the work-up of an isocyanate for vaporization of the isocyanate.

15. The process of claim 14 , comprising using the vaporization of the isocyanate to (i) at least partially remove the isocyanate from a residue-containing distillation bottoms stream from isocyanate production, and/or (ii) to separating a monomeric isocyanate fraction, which is vaporized, from a polymeric isocyanate fraction.

16. The process of claim 14 , wherein the isocyanate is selected from the group consisting of tolylene diisocyanate, a diisocyanate and/or polyisocyanate of the diphenylmethane series, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, and dicyclohexylmethane diisocyanate.

17. The process of claim 15 , wherein the isocyanate is selected from the group consisting of tolylene diisocyanate, a diisocyanate and/or polyisocyanate of the diphenylmethane series, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, and dicyclohexylmethane diisocyanate.

Assignees

• Covestro Deutschland Ag

Inventors

• Drumm Christian
• Steffens Friedhelm
• Hoffmann Dieter

Classifications

• B01D19/0057

  the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet · CPC title

• B01D19/0036

  Flash degasification (the other groups take precedence) · CPC title

• B01D3/008 Primary

  Liquid distribution · CPC title

• B01D1/065

  by film evaporating · CPC title

• B01D1/0064

  Feeding of liquid into an evaporator · CPC title