Method for unblocking pores in a selective catalytic reduction catalyst

Patent metadata

Field	Value
Publication number	US-12064756-B2
Application number	US-201917778063-A
Country	US
Kind code	B2
Filing date	Nov 25, 2019
Priority date	Nov 25, 2019
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

The invention concerns a method for unblocking pores in a metal zeolite based selective catalytic reduction (SCR) catalyst. The method includes filling, at least partially, the SCR catalyst with a liquid, the liquid being preferably distilled water. The method includes letting said liquid inside the SCR catalyst enough time to allow said liquid to dissolve, at least partially, the obstructions and to penetrate into the pores. The method includes heating the SCR catalyst at a temperature above the ebullition temperature of the liquid so as to vaporize the part of the liquid remained into the pores, and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores, wherein no hydrocarbons are injected during the step of heating.

First claim

The invention claimed is:

1. A method for unblocking pores blocked by obstructions, inside a selective catalytic reduction (SCR) catalyst comprising a zeolite, whereby the SCR catalyst is contained inside a muffler which is part of an exhaust after treatment system (EATS) of a vehicle, wherein the method includes:
filling in which a liquid is introduced inside the muffler so as to fully immerse each SCR catalyst into the liquid;
soaking during which a proportion of the liquid introduced inside the muffler spreads into the pores of the zeolite;
draining, at which the excess of liquid introduced inside the muffler is removed out of the muffler; and
drying, at which the SCR catalyst is heated at a temperature above an ebullition temperature of the liquid so as to vaporize the liquid remaining in the pores and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores, and wherein no hydrocarbons are injected during the drying.

2. The method according to claim 1 , wherein the step of drying comprises letting hot gas, comprising at least one of exhaust gas or hot air, flowing through the muffler.

3. The method according to claim 1 , further comprising a preliminary step of regeneration.

4. The method according to claim 3 , wherein the preliminary step of regeneration comprises a first regeneration sub-step at a high temperature, and/or a second regeneration sub-step at a lower temperature.

5. The method according to claim 1 , wherein no urea is injected during drying.

6. The method according to claim 1 , wherein the duration of soaking is comprised between 10 minutes and 120 minutes.

7. The method according to claim 1 , wherein drying is implemented by heating the SCR catalyst at a maximal temperature comprised between 250° C. and 470° C.

8. The method according to claim 1 , wherein drying lasts during a period of time comprised between 20 minutes and 120 minutes.

9. The method according to claim 1 , wherein the drying is followed by a step comprising essentially in a parked De-SOx regeneration to remove sulphur and its derivatives.

10. The method according to claim 1 , wherein the filling consists in plugging an orifice of the muffler and in manually pouring the liquid into another orifice of the muffler.

11. The method according to claim 1 , wherein said liquid is distilled water.

12. The method according to claim 1 , wherein said liquid is an aqueous solution comprising acetic acid, with a pH between 2 and 4.

13. The method according to claim 1 , further comprising:
taking off the muffler from the vehicle;
plugging at least an outlet of the muffler;
putting the muffler taken off inside a container or a pit; and
orienting the muffler to place the SCR catalyst(s) in a lowest possible position into the muffler.

14. A vehicle, comprising a muffler inside which at least one SCR catalyst has been treated using the method according to claim 1 .

15. The method according to claim 13 , further comprising removing sensors integrated into the muffler.

16. The method according to claim 15 , wherein the sensors comprise at least one of a NOx sensor, a delta pressure sensor, and other sensors.

17. The method according to claim 1 , wherein the duration of soaking is between 30 minutes and 60 minutes.

18. The method according to claim 1 , wherein drying is implemented by heating the SCR catalyst at a maximal temperature comprised between 280° C. and 330° C.

19. The method according to claim 1 , wherein drying lasts during a period of time comprised between 30 minutes and 90 minutes.

20. The method of claim 4 , wherein the first regeneration sub-step at a high temperature comprises a parked regeneration.

Assignees

• Volvo Truck Corp

Inventors

• Iojoiu Eduard Emil
• Keghelian Patrice

Classifications

• B01D47/12

  Washers with plural different washing sections (B01D47/14 takes precedence) · CPC title

• B01J37/06

  Washing {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• F01N3/206

  Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents · CPC title

• F01N3/038

  by means of perforated plates defining expansion chambers associated with condensation and collection chambers · CPC title

• F01N3/2896

  Liquid catalyst carrier · CPC title