AU2006233241B2

AU2006233241B2 - Heat Treatment Means

Info

Publication number: AU2006233241B2
Application number: AU2006233241A
Authority: AU
Inventors: Charlie Martella
Original assignee: Actinon Pte Ltd
Current assignee: Actinon Pte Ltd
Priority date: 2005-11-14
Filing date: 2006-10-27
Publication date: 2011-09-22
Anticipated expiration: 2026-10-27
Also published as: AU2006233241A1

Abstract

-15 A particulate material heat treatment means comprising an upstanding column (11) having a particulate material inlet (13) at the upper end and a particulate material outlet (15) at its lower end, an intermediate portion (A) of the column 5 provided with a first fluid inlet means and first fluid outlet means, the first fluid inlet means connected to a source of heated gas (41, 43), the first fluid inlet means comprising a set of first fluid inlets (23) which are located over at least a portion of the length of the intermediate portion of the column, the first fluid outlet means comprising a set of first outlets (27) which are located over the at least a portion of 10 the length of the intermediate portion of the column, the fluid inlets and the fluid outlets and being in substantially opposed relation to each other across the column, a cooling means (33) provided in a lower portion of the column downstream from the intermediate portion. _ii

Description

P/00/011 28/5/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: ANSAC Pty Ltd Actual Inventor Charlie Martella Address for service is: WRAY & ASSOCIATES Level 4, The Quadrant 1 William Street Perth, WA 6000 Attorney code: WR Invention Title: Heat Treatment Means The following statement is a full description of this invention, including the best method of performing it known to me: 1 -2 "Heat Treatment Apparatus" Field of the Invention This invention relates to a method for heat treatment of particulate material. Background 5 One particular application of the invention relates to a means of treating char in order to produce activated carbon. Previous methods which have been proposed for the production of activated carbon have involved the use of kilns in the form of a generally horizontal rotating cylinder into which charcoal is introduced and through which it is caused to pass. The cylinder is sealed and the carbon 10 contained within the cylinder is subjected to heat and super-heated steam. Because of the geometry of such kilns a large amount of energy must be provided to maintain the carbon at the desired temperature and in providing sufficient super-heated steam to ensure the required intimate contact between the steam and the carbon particles to effect activation. In addition the arrangement presents 15 significant problems in providing the appropriate seal at either end of the cylinder to prevent the entry of any oxidants into the chamber. Another particular application of the invention relates to the heat treatment (eg calcining) of particulate material. Previous methods which have been proposed for such heat treatment have involved the use of kilns in the form of a generally 20 horizontal rotating cylinder into which the material is introduced and through which it is caused to pass. Such methods have required a considerable amount of energy. Disclosure of the Invention Throughout the specification, unless the context requires otherwise, the word 25 "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

-3 Accordingly the invention resides in a particulate material heat treatment means comprising an upstanding column having a particulate material inlet at the upper end and a particulate material outlet at its lower end, an intermediate portion of the column provided with a first fluid inlet means and first fluid outlet means, the 5 first fluid inlet means connected to a source of heated gas, the first fluid inlet means comprising a set of first fluid inlets which are located over at least a portion of the length of the intermediate portion of the column, the first fluid outlet means comprising a set of first outlets which are located over the at least a portion of the length of the intermediate portion of the column, the fluid inlets and the fluid 10 outlets and being in substantially opposed relation to each other across the column, a cooling means provided in a lower portion of the column downstream from the intermediate portion. According to a preferred feature of the invention an upper portion of the length of the column upstream from the intermediate portion is provided with a second fluid 15 inlet means and a second fluid outlet means, the second fluid inlet means comprising set of second fluid inlets which are located over a portion of the upper portion of the length of the column, the second fluid outlet means comprising set of second fluid outlets located over the portion of the upper portion of the length of the column, the second fluid inlets and second fluid outlets being in opposed 20 relation across the column, the first fluid outlet means being connected to the second fluid inlet means. According to a preferred feature of the invention the flow of gas between the first fluid inlet means and the second fluid outlet means is induced by creation of a negative pressure downstream from the second fluid outlet means. 25 According to a preferred feature of the invention the intermediate portion of the column comprises a set of stations located at spaced intervals along the length of the intermediate portion, each station having a space of reduced dimensions through which the particulate material is caused to flow on its passage from the inlet to the outlet, each station having a first fluid inlet and a first fluid outlet to 30 each side of the space wherein the rate of flow of gas through the space is controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing from the first fluid inlet to the first fluid outlet.

-4 According to a preferred feature of the invention the upper portion of the column comprises a set of stations located at spaced intervals along the length of the upper portion, each station having a space of reduced dimensions through which the particulate material is caused to flow on its passage from the inlet to the outlet, 5 each station having a second fluid inlet and a second fluid outlet to each side of the space wherein the rate of flow of gas through the space is controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing from the second fluid inlet to the second fluid outlet. According to a preferred feature of the invention the cross-sectional configuration 10 of the intermediate portion of the column accommodating the particulate material is annular, the first fluid inlet means being provided around and along the outer wall of the intermediate portion and the first fluid outlet means being provided around and along inner wall of the intermediate portion. According to a preferred feature of the invention the cross-sectional configuration 15 of the upper portion of the column accommodating the particulate material is annular, the second fluid inlet means being provided around and along outer wall of the upper portion and the second fluid outlet means being provided around and along inner wall of the upper portion. According to a preferred feature of the invention the gas is substantially un 20 reactive to the particulate material. According to an alternative preferred feature of the invention gas is at least potentially reactive to the particulate material. According to a preferred feature of the invention the source for said gas comprises the exhaust from a combustion means. According to a preferred feature of the invention the fluid from the second fluid outlet means is introduced 25 into the combustion means for combustion of any combustible substances contained in the fluid. According to a preferred feature of the invention a first heat exchanger is provided in association with the combustion means and is associated with a source of water wherein the heated water from the first heat exchanger is introduced into the combustion means for the vaporisation of the 30 water and wherein the gas comprises a mixture of the exhaust gases of the combustion means and water vapour. According to a preferred feature of the -5 invention the combustion means comprises a first combustion chamber which accommodates the first heat exchanger and which receives the fluid from the second fluid outlet means, the combustion means further comprising a second combustion chamber which is the source of said gas, the outlet of the first heat 5 exchanger opening into the second combustion chamber. According to a preferred feature of the invention the cooling means comprises a second heat exchanger provided in association with the column, said second heat exchanger being connected to a source of water, the outlet of the second heat exchanger being connected to the inlet of the first heat exchanger. According to a 10 preferred feature of the invention the cross-sectional configuration of the lower portion of the column accommodating the particulate material is annular, the second heat exchanger being provided around and along the outer and inner wall of the lower portion. According to a preferred feature of the invention the cooling means comprises a 15 third fluid inlet means along at least a portion of the length of the lower portion of the length of the column and a third fluid outlet means along at the at least a portion of the length of the lower portion the length of the lower portion of the length of the column, the third fluid inlet means comprising set of third fluid inlets, the third fluid outlet means comprising set of third fluid outlets, the third fluid inlets 20 and the third fluid outlets being in opposed relation across the column. According to a preferred feature of the invention the third fluid outlet means are connected to the first fluid inlet means. According to a preferred feature of the invention the first fluid inlet means comprises a combustion means. 25 The invention will be more fully understood in the light of the following description of specific embodiments. Brief Description of the Drawings The description is made with reference to the accompanying drawings of which: -6 Figure 1 is a schematic illustration of the first embodiment; and Figure 2 is a general sectional elevation of a column according to the first embodiment. Detailed Description of the Specific Embodiment 5 The first embodiment is directed towards a means for the manufacture of activated carbon utilising a feed stock of char which may comprising either coal char or charcoal. The embodiment comprises an upstanding column 11 having an upper end defined by an inlet hopper 13 and an outlet 15 is provided at the lower end of the 10 column 11. The column is associated with a combustion means which is intended to generate the required gas and heat for activation of the carbon and which will be subsequently described in further detail. The hopper 13 is supplied with a suitable char material which is to be activated and which is allowed to flow through the column in a controlled manner and pass from the column through the 15 outlet 15. The interior of the column 11 between the inlet 13 and the outlet 15 accommodates a central plenum 21 which is closed at either end and defines an annular flow path through the column for the char. The annular flow path comprises an intermediate portion A, an upper portion B and a lower portion C. A 20 first fluid inlet means comprising a set of first fluid inlets 23 is provided around and along the external wall of the intermediate portion A of the column and a first fluid outlet means in the wall of the central plenum in the form of first fluid outlets 25 (see Figure 2) is provided around and along the internal wall of the intermediate portion A of the central plenum. The first fluid inlets and first fluid outlets are 25 generally in opposed relation to each other to each side of the annular flow path for the particulate material through the intermediate portion. In addition a second fluid inlet means in the form of second fluid inlets 27 is located around and along the inner wall of the upper portion B of the central -7 plenum (see Figure 2) and a second fluid outlet means in the form of a set of second fluid outlets 29 is provided around and along the external wall of the upper portion B of the column. The lower portion C of the column is provided with a cooling means in the form of 5 a heat exchanger in the form of a water jacket 33 provided around the outer wall of the column and the inner wall of the annular flow path in that region. The water jacket comprises the second heat exchanger of the invention . The inlet 35 of the water jacket is connected to a source of cool water while the outlet 37 is connected to a first heat exchanger 39 provided in the combustion means. The 10 combustion means comprises a first combustion chamber 41 which accommodates a first burner 43 and the first heat exchanger 39. The combustion means further comprises a second combustion chamber 43 having a second burner 45 to deliver water vapour into the second combustion chamber. The outlet of the first heat exchanger 39 opens into the second combustion chamber 15 43. The heat generated at the first combustion chamber 41 is sufficient to vaporise the water within the second heat exchanger 39 whereby heated water vapour is delivered into the second combustion chamber 43 to be subjected to further heating and to be intermixed with the combustion products generated in the second combustion chamber. The exhaust from the second combustion 20 chamber which contains the combustion products generated by the second burner 45 together with the super heated water vapour is delivered to each of the first fluid inlets 23. The second fluid outlet 31 is connected to the first combustion chamber 41 in order that any combustible materials contained within that fluid flow will be 25 combusted within the first combustion chamber 41. The exhaust for the first combustion chamber is provided with an exhaust fan 47 and as a result a fluid flow is generated from the second combustion chamber to the first fluid inlets, then to the first fluid outlets, then into the central plenum 31, then to the second fluid inlets, then to the second outlets and finally to the first combustion chamber 30 41.

-8 As a result of the fluid flow generated by the exhaust fan 47 the char contained in the intermediate portion A of the column is subjected to high temperature gaseous flow which serves to heat and activate the carbon in that zone. On the gas having exhausted from the particulate material in the intermediate portion of the column it 5 is then accumulated within the central plenum 21 and caused to pass through the particulate material in the upper portion B of the column. In so doing the gas serves to preheat the material prior to it passing into the intermediate zone A. The flow of gas through the particulate material in the upper portion B of the column also serves to isolate the intermediate zone A from the atmosphere. 10 Therefore a large proportion of the heat of the gas flowing from the second combustion chamber 43 into the column is extracted from either the intermediate portion A of the column or the upper portion B of the column. In addition the activation process is endothermic. The gas which flows from the second outlets 31 may be expected to contain amongst other things particulate carbonaceous 15 material, carbon monoxide, hydrogen as well as carbon dioxide. The introduction of that material into the first combustion chamber 41 serves to oxidise all such materials and utilise the heat generated by such action to heat the heat exchanger 39. The water jacket 33 (i.e. the second heat exchanger) of the lower portion C of the 20 column serves to cool the activated carbon passing through the lower portion of the column such that on it reaching the outlet 15 the temperature of the carbon is below combustion temperature. The heat generated by such cooling action is absorbed by the water which then flows to the second heat exchanger 39 which serves to further the heat and vaporise the water before it is introduced into the 25 second combustion chamber. The outlet 15 is controlled by a suitable conveyor (such as a screw conveyor) which serves to controllably deliver the activated carbon from the column without allowing the entry of any air into the column. The fluid inlets and outlets are illustrated in greater detail in Figure 2. The first 30 fluid inlets comprise an annular plenum 51 provided around the outer wall of the column into which the gas from the second combustion chamber 43 is caused to -9 pass. The inner face of each plenum chamber 51 is defined by inwardly and downwardly oblique baffle 53 which is spaced inwardly from the upper edge of the adjacent lower baffle. Similarly the second fluid outlets are formed with a plenum 51 and are associated with an outwardly and downwardly oblique baffle 53. The 5 plenum 51 of the second fluid outlets are connected to the first combustion chamber 41. The first fluid outlets 27 are defined by a series of outwardly and downwardly inclined baffles 55 on the wall of the central plenum 21 where the lower edge of each baffle is spaced outwardly from the upper most edge of the adjacent lower baffle and an opening is provided into the plenum 21 between the 10 adjacent baffles. Similarly the second fluid inlets are provided on the outer wall of the central portion 21 through a set of baffles 55. As a result of the presence of the opposed baffles of the first fluid inlets and outlets and the opposed baffles of the second fluid inlets and outlets, the flow path for the particulate material within the intermediate and upper portions A and B of 15 the column are of a varying cross sectional area. As a result the particulate material is caused to accelerate and decelerate in its passage through the portions A and B. Such acceleration and deceleration causes variations in density along the column which subsequently permits gaseous flow across the annular space accommodating the char material and maximise the heat exchange 20 between the gas and the particulate material. The first embodiment as described above provides a carbon activation plant which ensures an efficient heating of the carbon and contacting of the carbon with super heated water vapour with a potential reduction in the amount of the water and the heat that is required to activate the carbon compared to earlier arrangements. 25 The second embodiment of the invention is intended for the heat treatment of a particulate material such as titanium dioxide which may be pelletised. In the case of this form of heat treatment, the heat exchangers of the first embodiment which are used for the generation of water vapour are not required. The second embodiment comprises the column of the first embodiment having the 30 intermediate zone in which the material is subjected to the required temperature while the material is preheated in the upper zone and cooled in the lower zone. In -10 the second embodiment the first fluid inlet means is associated with at least one burner wherein the exhaust of the burners open into the intermediate zone. Again as in the first embodiment the first fluid outlet means open into the second fluid inlet means of the upper portion and the fluid passing from the second fluid outlet 5 means is exhausted. In the lower portion the outer walls of the lower portion are associated with a third fluid inlet means which comprises a set of third fluid inlets along the length of the lower portion where the third fluid inlets are of the same form as the first fluid inlets. In addition the lower portion is provided with a third fluid outlet means in the central plenum where the third fluid outlet means is of a 10 similar form to the first fluid outlet means. The portion of the plenum housing the third fluid outlets is isolated from the portion of the central plenum housing the first fluid outlet means. The third fluid inlet means is connected to a source of air substantially at ambient temperature and the third fluid outlet means is connected to the first fluid inlet means whereby the heated air which is exhausted from the 15 lower portion is delivered to the combustion means. Such an arrangement serves to increase the efficiency of the combustion means and the temperatures available for a given quantity of fuel. It is believed that the second embodiment will provide significant efficiencies over existing heat treatment and calcining kilns which utilise rotating cylinders. 20 The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products and methods are clearly within the scope of the invention as described herein.

Claims

1. A particulate material heat treatment means comprising an upstanding column having a particulate material inlet at the upper end and a particulate material outlet at its lower end, an intermediate portion of the column provided with a first fluid inlet means and first fluid outlet means, the first 10 fluid inlet means connected to a source of heated gas, the first fluid inlet means comprising a set of first fluid inlets which are located over at least a portion of the length of the intermediate portion of the column, the first fluid outlet means comprising a set of first outlets which are located over the at least one portion of the length of the intermediate portion of the column, the 15 fluid inlets and the fluid outlets being in substantially opposed relation to each other across the column, and a cooling means is provided in a lower portion of the column downstream from the intermediate portion, wherein the intermediate portion of the column further comprises a set of stations located at spaced intervals along the length of the intermediate portion, 20 each station having a space of reduced dimensions through which the particulate material is caused to flow on its passage from the inlet to the outlet.

2. A particulate material heat treatment means as claimed at claim 1 wherein 25 an upper portion of the length of the column upstream from the intermediate portion is provided with a second fluid inlet means and a second fluid outlet means, the second fluid inlet means comprising set of second fluid inlets which are located over a portion of the upper portion of the length of the column, the second fluid outlet means comprising set of second fluid outlets 30 located over the portion of the upper portion of the length of the column, the second fluid inlets and second fluid outlets being in opposed relation across the column, the first fluid outlet means being connected to the second fluid inlet. 35

3. A particulate material heat treatment means as claimed at claim 2 wherein the flow of gas between the first fluid inlet means and the second fluid outlet 12 means is induced by creation of a negative pressure downstream from the second fluid outlet means.

4. A particulate material heat treatment means as claimed at claim 1 or 2 or 3, 5 wherein each station comprises a first fluid inlet and a first fluid outlet to each side of the space wherein the rate of flow of gas through the space is controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing from the first fluid inlet to the first fluid outlet. 10

5. A particulate material heat treatment means as claimed at claim 2 or claim 3 or 4 as dependant from claim 2 wherein the upper portion of the column comprises a set of stations located at spaced intervals along the length of the upper portion, each station having a space of reduced dimensions 15 through which the particulate material is caused to flow on its passage from the inlet to the outlet, each station having a second fluid inlet and a second fluid outlet to each side of the space wherein the rate of flow of gas through the space is controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing from the second 20 fluid inlet to the second fluid outlet.

6. A particulate material heat treatment means as claimed at any one of the preceding claims wherein the cross-sectional configuration of the intermediate portion of the column accommodating the particulate material 25 is annular, the first fluid inlet means being provided around and along the outer wall of the intermediate portion and the first fluid outlet means being provided around and along inner wall of the intermediate portion.

7. A particulate material heat treatment means as claimed at claim 2 or any 30 one of claims 3, 4, 5 or 6 as dependant from claim 2 wherein the cross sectional configuration of the upper portion of the column accommodating the particulate material is annular, the second fluid inlet means being provided around and along outer wall of the upper portion and the second fluid outlet means being provided around and along inner wall of the upper 35 portion. 13

8. A particulate material heat treatment means as claimed at ay one of the preceding claims wherein the gas is substantially un-reactive to the particulate material. 5

9. A particulate material heat treatment means as claimed at any one of claims 1 to 7 wherein gas is at least potentially reactive to the particulate material.

10 10. A particulate material heat treatment means as claimed at claim 8 or 9 wherein the source for said gas comprises the exhaust from a combustion means.

11. A particulate material heat treatment means as claimed at claim 10 wherein 15 the fluid from the second fluid outlet means is introduced into the combustion means for combustion of any combustible substances contained in the fluid.

12. A particulate material heat treatment means as claimed at claim 10 or 11 20 wherein a first heat exchanger is provided in association with the combustion means and is associated with a source of water wherein the heated water from the first heat exchanger is introduced into the combustion means for the vaporisation of the water and wherein the gas comprises a mixture of the exhaust gases of the combustion means and 25 water vapour.

13. A particulate material heat treatment means as claimed at claim 12 wherein the combustion means comprises a first combustion chamber which accommodates the first heat exchanger and which receives the fluid from 30 the second fluid outlet means, the combustion means further comprising a second combustion chamber which is the source of said gas, the outlet of the first heat exchanger opening into the second combustion chamber. 14

14. A particulate material heat treatment means as claimed at claims 12 or 13 wherein the cooling means comprises a second heat exchanger provided in association with the column, said second heat exchanger being connected to a source of water, the outlet of the second heat exchanger being 5 connected to the inlet of the first heat exchanger.

15. A particulate material heat treatment means as claimed at claim 14 wherein the cross-sectional configuration of the lower portion of the column accommodating the particulate material is annular, the second heat 10 exchanger being provided around and along the outer and inner wall of the lower portion.

16. A particulate material heat treatments as claimed at any one of the preceding claims wherein the cooling means comprises a third fluid inlet 15 means along at least a portion of the length of the lower portion of the length of the column and a third fluid outlet means along at the at least a portion of the length of the lower portion the length of the lower portion of the length of the column, the third fluid inlet means comprising set of third fluid inlets, the third fluid outlet means comprising set of third fluid outlets, 20 the third fluid inlets and the third fluid outlets being in opposed relation across the column.

17. A particulate material heat treatment means as claimed at claim 16 wherein the third fluid outlet means are connected to the first fluid inlet means. 25

18. A particulate material heat treatment means as claimed at any one of the preceding claims wherein the first fluid inlet means comprises a combustion means. 30

19. A particulate material heat treatment means substantially as herein described with reference to the accompanying drawings.