Arrangement and method in soda recovery boiler

Patent metadata

Field	Value
Publication number	US-9920476-B2
Application number	US-201314428884-A
Country	US
Kind code	B2
Filing date	Sep 18, 2013
Priority date	Sep 19, 2012
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An arrangement and a method in a soda recovery boiler, in a furnace ( 1 ) of which recovery boiler there are arranged screen tubes ( 7 ) and which recovery boiler comprises a second pass ( 9 ) in which is arranged at least one superheater ( 4 ′). The second pass ( 9 ) is arranged for being cooled with cooling medium coming from the screen tubes ( 7 ).

First claim

The invention claimed is:

1. An arrangement in a soda recovery boiler comprising:
a furnace comprising arranged screen tubes,
a second pass comprising a second pass ash hopper, the second pass ash hopper comprising at least one of front wall cooling pipes or rear wall cooling pipes, and
at least one superheater arranged in the second pass,
wherein:
the second pass is cooled with cooling medium coming from the screen tubes,
the front wall cooling pipes and/or the rear wall cooling pipes are connected to receive the cooling medium from the screen tubes, and
the cooling pipes of the ash hopper form a gastight front and/or rear wall of the ash hopper.

2. The arrangement of claim 1 , wherein the second pass ash hopper comprises an ash hopper supply header that is arranged in the lower part of the ash hopper and connected with a connection pipe to the screen tubes to receive cooling medium and to distribute the cooling medium into said front wall cooling pipes and/or rear wall cooling pipes.

3. The arrangement of claim 1 , wherein the cooling pipes of the ash hopper are, higher up, arranged to provide grid tubes so as to allow flue gases to pass through.

4. The arrangement of claim 3 , wherein the cooling pipes form a gastight ceiling for the second pass and are connected via a collection header to a drum.

5. The arrangement of claim 2 , wherein the cooling pipes of the ash hopper are, higher up, arranged to provide grid tubes so as to allow flue gases to pass through.

6. The arrangement of claim 5 , wherein the cooling pipes form a gastight ceiling for the second pass and that they are connected via a collection header to a drum.

7. The arrangement of claim 1 , wherein in that cooling medium from the screen tubes is arranged for being conveyed to at least one side wall of the second pass.

8. The arrangement of claim 1 , wherein at least one side wall of the second pass is connected with a downcomer to the drum to receive cooling water.

9. The arrangement of claim 1 , wherein at least one side wall of the second pass is connected to steam circulation so as to cool the side walls.

10. The arrangement claim 1 , wherein the screen tubes comprise tube elements including superimposed heat surface pipes, each of the tube elements being connected with a specific connection pipe to the second pass.

11. A method in a soda recovery boiler, the method comprising the steps of:
providing a soda recovery boiler comprising:
a second pass comprising a second pass ash hopper,
screen tubes arranged in a furnace, and
at least one superheater arranged in the second pass, and

cooling the second pass with cooling medium conveyed from the screen tubes,
wherein:
the cooling medium is conveyed to at least one of a front wall or a rear wall of the second pass ash hopper from the screen tubes, and
the cooling pipes of the ash hopper form a gastight front and/or rear wall of the ash hopper.

12. The method of claim 11 , wherein the cooling medium from the screen tubes is conveyed to at least one side wall of the second pass.

13. The method of claim 11 , wherein cooling water from a drum is conveyed to at least one side wall of the second pass.

14. The method of claim 11 , wherein side walls of the second pass are connected to steam circulation of the boiler.

Assignees

• Valmet Technologies Oy

Inventors

• Niemi Piia
• Isoniemi Markku
• Juutilainen Tero
• Haaga Kari

Classifications

• D21C11/12 Primary

  Combustion of pulp liquors · CPC title

• F22B21/343

  the vertical radiation combustion chamber being connected at its upper part to a sidewards convection chamber · CPC title

• F22B1/20

  using heat evolved in a solution absorbing steam; Soda steam boilers · CPC title

• F23J15/06

  of coolers · CPC title

• F22G1/02

  with heat supply by hot flue gases from the furnace of the steam boiler · CPC title