Multi-compartment reactor and method for controlling retention time in a multi-compartment reactor

Patent metadata

Field	Value
Publication number	US-9827547-B2
Application number	US-201313972439-A
Country	US
Kind code	B2
Filing date	Aug 21, 2013
Priority date	Aug 15, 2013
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A method is disclosed for controlling retention time in a reactor, such as an autoclave, having a plurality of compartments separated by dividers with underflow openings. A retention time of the reaction mixture is calculated and compared with an optimal retention time, and the volumes of the reaction mixture in the compartments are adjusted while maintaining the flow rate of the reaction mixture, so as to change the retention time to a value which is closer to the optimal retention time. The reactor may include a level sensor in the last compartment for generating volume data; a control valve for controlling the liquid level in the last compartment; and a controller which receives volume data from the level sensor and controls operation of the control valve.

First claim

What is claimed is:

1. A method for controlling retention time of an aqueous reaction mixture in a reactor, the method comprising:
(a) providing said reactor, wherein the reactor comprises a plurality of compartments including a first compartment and a last compartment, and wherein each adjacent pair of said compartments is separated by a divider having at least one opening for flow of the reaction mixture, wherein the at least one opening in each divider is located below a liquid level of the reaction mixture in the compartments which are separated by the divider;
(b) providing a level sensor in one of the compartments, wherein the level sensor is configured to generate level information regarding the liquid level in said compartment:
(c) providing a control valve to control the liquid level in the last compartment:
(d) providing a controller which is configured to receive the level information from the level sensor, and to control operation of the control valve:
(e) passing the aqueous reaction mixture through the reactor at a first flow rate, wherein the reaction mixture flows through the reactor from the first compartment to the last compartment, wherein most or all of the reaction mixture flows between each adjacent pair of said compartments by passing through the at least one opening in the divider separating the adjacent compartments;
(f) generating the level information with the level sensor, and transmitting the level information to the controller; and
(g) controlling operation of the control valve with the controller to vary a rate at which the product mixture is withdrawn from the last compartment so as to simultaneously adjust the liquid levels in all the compartments and thereby change the retention time.

2. The method according to claim 1 , wherein the reactor has an inlet through which the first compartment receives the reaction mixture.

3. The method according to claim 1 , wherein the reactor has an outlet through which the reaction mixture is withdrawn from the reactor.

4. The method according to claim 3 , wherein the reaction mixture is withdrawn from the reactor through an outlet tube located in the last compartment.

5. The method according to claim 1 , further comprising agitation of the reaction mixture as it flows through the reactor.

6. The method according to claim 1 , further comprising injection of an oxygen-containing gas or liquid reagent into the reaction mixture as it flows through the reactor.

7. The method according to claim 1 , wherein the reactor is an autoclave.

8. The method according to claim 1 , wherein the aqueous reaction mixture is an aqueous slurry of an ore or an ore concentrate containing one or more metal values.

9. The method according to claim 1 , wherein all of the openings in all of the dividers are below the liquid levels in all the compartments.

10. The method according to claim 1 , wherein each said divider has a height which is greater than the liquid levels in the compartments which are separated by said divider, such that all of the reaction mixture passes through the openings in the dividers.

11. The method according to claim 1 , wherein the controller is configured to calculate the retention time of the reaction mixture based on the first flow rate and the level information generated by the level sensor.

12. A reactor with retention time control, comprising:
(a) a plurality of compartments, including a first compartment and a last compartment;
(b) one or more dividers, each of said dividers separating an adjacent pair of said compartments, wherein each of the dividers has at least one opening for flow of a reaction mixture through the divider, and wherein each said opening is located below a minimum liquid level in each of said adjacent pair of compartments, wherein the divider has a height which is greater than a maximum liquid level in each of said adjacent pair of compartments, and wherein a continuous head space is provided within the reactor above the dividers;
(c) an inlet in said first compartment;
(d) an outlet in said last compartment;
(e) a level sensor in said last compartment for generating volume data;
(f) a control valve for controlling the liquid level in the last compartment; and
(g) a controller configured to receive the volume data from the level sensor and for controlling operation of the control valve.

13. The reactor according to claim 12 , further comprising at least one agitator in each of the compartments and means for injecting an oxidizing gas or liquid reagent into each of the compartments.

14. The reactor according to claim 12 , wherein a total area of at least one opening in each of the dividers is sufficient to permit flow therethrough of all the reaction mixture.

15. The reactor according to claim 12 , wherein a total area of at least one opening in each of the dividers is substantially the same.

Assignees

• Hatch Ltd

Inventors

• Fraser Kevin S
• Pearson Murray S
• Mccombe William E

Classifications

• Y02P10/20

  Recycling · CPC title

• B01J19/0006 Primary

  Controlling or regulating processes (controlling or regulating in general G05) · CPC title

• B01J19/1862

  placed in series · CPC title

• B01J2219/182

  horizontal · CPC title

• B01J19/006

  Baffles · CPC title