AU2003203773C1 - Apparatus For Treatment of Particulate Material - Google Patents

Abstract

Abstract A particulate material treatment means comprising a flow path (11) having an upper end and a lower end, an inlet (15) provided at the upper end and an outlet (17) 5 provided at the lower end, the flow path provided with a set of stations (19) located at spaced intervals along the length of the flow path, each station having a space 921) 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 gas inlet (33) and a gas outlet (37) located to each side of the space, the gas inlet being connected to a 10 source of heated gas, the gas being substantially unreactive to the particulate material, the rate of flow of the gas through the space being controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing to the gas outlet.

Description

P/00/011 2815/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: ANSAC Pty Ltd Actual Inventor Mr Charlie Martella & Mr Matthew Martella Address for service is: WRAY & ASSOCIATES Level 4, The Quadrant 1 William Street Perth, WA 6000 Attorney code: WR Invention Title: "Apparatus for Treatment of Particulate Material" Details of Associated Provisional Application No(s): PS2162 filed on 8 May 2002 The following statement is a full description of this invention, including the best method of performing it known to me: 1 -2 "Apparatus for Treatment of Particulate Material" Field of the Invention This invention relates to an apparatus for treatment of particulate material and in particular the heating of such particulate material. 5 Disclosure of the Invention Accordingly the invention resides in a particulate material treatment means comprising a flow path having an upper end and a lower end, an inlet provided at the upper end and an outlet provided at the lower end, the flow path provided with a set of stations located at spaced intervals along the length of the flow path, each station 10 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 gas inlet and a gas outlet located to each side of the space, the gas inlet being connected to a source of heated gas, the gas being substantially unreactive to the particulate material, the rate of flow of the gas through the space being controlled 15 such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing to the gas outlet. According to a preferred feature of the invention the heat delivered to the upper most station is greater than the heat being delivered to the lower most station. According to a preferred feature of the invention the heat being delivered by the stations varies 20 such that the amount of heat varies with the distance from the inlet According to a preferred feature of the invention the heat delivered to each station is less than the preceding station. According to a preferred feature of the invention the heat input to each station is controlled by monitoring the temperature of the gas flowing into and/or from the space. According to a preferred feature of the invention the 26 temperature of the gas flowing into the space is controlled by an injection means which is adapted to spray water into the gas whereby the magnitude of water being sprayed into the gas is controlled according to the desired temperature of the gas to be delivered to the space. According to a preferred feature of the invention the heat input is controlled by varying the flow rate of gas through the particulate material.

-3 According to a preferred feature of the invention space is of an annular configuration defined by an inlet manifold provided around the inner face of the first flow path and connected to the gas inlet, and an outlet baffle which accommodates the gas outlet. According to a preferred feature of the invention the inlet manifold defines an 5 annular plenum into which the gas inlet opens wherein the lower portion of the plenum opens into the space. According to a preferred feature of the invention the outlet baffle comprises a central space closed at its upper end and open at its lower end. According to a preferred feature of the invention the upper outer surface of the baffle is configured to provide to promote the flow of particulate material past the 10 space, the gas outlet being accommodated within the central space. According to a preferred feature of the invention the upper outer surface of the baffle has a generally downwardly divergent configuration and the lower face of the outlet baffle is open. According to a preferred feature of the invention the outer surface of the baffle is generally conical. 15 According to a preferred feature of the Invention the treatment means further comprises a second flow path having a second inlet and a second outlet the second inlet being connected to the outlet of the first flow path, said second flow path being generally horizontal and comprising a rotating cylindrical surface along which the particulate material is caused to pass in its passage from the second inlet to the 20 second outlet, a heating means associated with the second flow path to heat the cylindrical surface, the atmosphere of the second flow path being substantially unreactive to the particulate material. According to a preferred feature of the invention the exhaust from the heating means is connected to the gas Inlet of each station. According to a preferred feature of the invention the second flow path is 25 provided with an exhaust adapted to enable the escape of gaseous fluids generated from the particulate material in its passage through the second flow path. According to a preferred feature of the invention the gas which is exhausted from the second flow path is utilised at least in part as the fuel for the heating means. According to a preferred feature of the invention the particulate material comprises a 30 carbonaceous material. According to a preferred feature of the invention the particulate material comprises coal.

-4 Throughout the specification the term carbonaceous material shall be taken to include wood, wood chips, sawdust, charcoal, mixtures of the aforesaid materials and mixtures of said carbonaceous materials with other substances. In addition throughout the specification the term coal shall be taken to comprise coal, coal 5 based or coal-sourced products such as coke and like carbonaceous materials and , mixtures incorporating coal or a coal-based product. The invention will be more fully understood in the light of the following description of one specific embodiment. Brief Description of the Drawings 10 The description is made with reference to the accompanying drawings of which: Figure 1 is a schematic side elevation of a treatment means according to the embodiment; and Figure 2 is a part schematic sectional view of the first flow path according to the embodiment illustrating the configuration of a station. 15 Detailed Description of Specific Embodiment The embodiment comprises a means for treating coal in order to generate char and comprises a first flow path 11 which serves as a pre-drier for the coal and a second path 13 In which the coal is heated to generate char. The first flow path comprises an upper inlet 15 and a lower outlet 17 and the coal Is 20 caused to flow the length of the first flow path 11 from the inlet 15 to the outlet 17. The first flow path 11 is provided with a plurality of stations 19 through which the coal Is caused to pass sequentially in its passage along the first flow path. Each station comprises a space which is of reduced cross sectional area compared tot eh cross sectional area to each side of the station. The space 21 is annular in 25 configuration and is defined between annular inlet manifold 23 provided around the inner face of the first flow path II and a central outlet baffle 25.

-6 The inlet manifold 23 is defined by annular baffle provided around the interior of the flow path which defines a generally downwardly convergent surface 27 terminating at an inner rim 29 having a diameter less than that of the flow path and further provided with a lower skirt 31 which is generally downwardly divergent and which 5 terminates in spaced relation from the inner face of the flow path 11. The inlet manifold is connected to a gas inlet 33. The outlet baffle 25 is of a generally conical configuration and is located centrally with respect to the Inlet manifold 23 and is spaced from the inlet manifold 23 to define the annular space 21 between its outer surface and the inner rim 29 of the skirt 31 of the inlet manifold. The surface of the 10 outlet baffle is generally parallel to the skirt 31 of the adjacent inlet manifold. The lower face 35 of the baffle 25 is open and accommodates the gas outlet 37 while the entry Into the gas outlet is directed upwardly. The outlet 17 of the first flow path 11 opens into a screw conveyor 39 which is intended to deliver material into second flow path 13. 15 The second flow path 13 comprises a rotating cylindrical drum having its central axis substantially horizontal. The interior wall of the drum 41 is provided with suitable means to promote the controlled movement of particulate material along the drum from the inlet of the drum which is associated with the screw conveyor 39 to the outlet 43 of the drum. The outlet of the second drum 43 is provided with a second 20 screw conveyor 45 which serves to controllably deliver product exiting the drum 41 to a suitable storage means (not shown). The drum 41 is associated with a set of gas burners 47 which are in heat conductive relationship with the external surface of the drum in order to heat the walls of the drum and as a result the coal passing though the drum. The interior of the drum is 25 isolated from the ambient conditions such that the atmosphere contained within the drum whilst being heated and accommodating the coal is unreactive to the coal. The drum 31 is associated with an exhaust 49 which is intended to exhaust from the drum the volatiles which are generated from the coal as it is caused to pass along the length of the drum. The volatiles which are exhausted from the exhaust 49 are 30 then utilized, at least in part, as the fuel for the burners 47.

The combustion chamber which accommodates the burners 47 is associated with a flue 51 which is connected to each of the gas inlets 33 whereby the combustion products generated by the burners 47 is delivered into inlet manifold of each of the stations 19. The rate of delivery of the exhaust gases into the space can be 5 controlled through a suitable valve in order that heat which is being delivered to each of the stations will vary and in order that the greatest amount of heat is delivered to the coal located at the upper end of the first flow path 11 and the amount of heat being delivered into the stations decreases as the coal which is passing through each of the stations is dried. Each of the gas outlets are connected to a vacuum 10 extraction fan which draws the combustion products from the flue 51, into each of the stations, through the coal passing through the space 21 of each of the stations and then to the respective gas outlet. Because of the location of the gas outlets 37 within their respective outlet baffle 25 and the orientation of the gas outlet 37 there is little or no entrained material which is carried to the gas outlet. 15 it is the function of the first flow path 11 to effect at least a partial pre-drying of the coal before it is delivered into the second flow path 13. The purposes of utilising the first flow path 11 as a pre-drier serves to reduce the heat which is required in the second flow path 13 to dry off the residual water in the coal before the coal is charred and therefore serves to maximise the utilisation of heat in heating the coal in 20 the second flow path. Furthermore, the configuration of each of the stations is such that the particulate material is caused to pass through a space which is defined between the inlet manifold 23 and the outlet baffle 25 reduces the cross-sectional area of material through which the gas is required to pass on its passage from the gas inlet to the gas outlet. Furthermore, because of the configuration of the station, 25 the particulate material tends to flow at a faster rate as it departs from the space 21 which reduces the particle density across that location and therefore serves to enhance the passage of the gas through the particulate material flowing from the space 21. It is believed that the heating action which is induced on each of the particles as it 30 passes through each of the stations serves to heat the outer surface of the coal particle and cause the expulsion of water contained on the particle at that surface without the interior of the particle having been heated. The expulsion of such water from the particle serves to draw water contained from within the particle towards its -7 outer surface and when the particle then passes through the next station the water which has been drawn to the outer surface of the particle will then be expelled. This action serves to avoid the heating of the interior of the particle to a level at which the water contained within the particle may vaporise and as a result cause fracturing or 5 shattering of the particle. In addition the heating of the particle is controlled in order that the surface of the particle is not over heated in a manner which will cause degradation (structurally and otherwise) of the surface of the particle. As a result the coal particles in their passage through the first flow path 11 suffer relatively low disintegration or breakdown and there is little or no generation of fines in the 10 passage of the coal through the first flow path. Furthermore, because of the larger surface area of the lower face of the outlet baffle 25 compared to the cross-sectional area of the gas outlet 37 the flow rate of gas which Is generated through the space 21 is relatively low which serves to prevent the entrainment of particles from the particulate coal into the gas stream as the coal passes through the space 21. 15 In addition, it is envisaged that the magnitude of the volatiles which are exhausted from the coal as a result of its charring within the second flow path 13 may be greater than that which is required to fuel the burners 47 and as a result the excess volatiles can be extracted and utIllsed for another purpose. According to an alternative embodiment of the invention the treatment apparatus 20 comprises a drier which comprises the first flow path 11 only which can be utilised for the drying of particulate material such as iron-ore fines, mineral sands or the like where the outlet of the first flow path 11 Is able to deliver the resultant dried particulate material to a suitable reactor. According to a further embodiment of the Invention the treatment apparatus 25 comprises a reactor which comprises the first flow path 11 which can be utilised for the treating of particulate material with a suitable gas which may be heated or unheated for the purposes of effecting a close an intimate contact between the particulate material and the gas to cause the particulate to be treated. The resultant material may then be subjected to further treatment and the embodiment may 30 comprise one of a number of reactors through which the particulate material is required to pass.

-8 Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as comprisess" 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. 5 It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiments described above,

Claims (20)

1. A dryer, for use with a particulate material, the dryer comprising a first flow path having an upper end and a lower end and a length, an inlet provided at the upper end of the first flow path and an outlet provided at the lower end of the first flow path, the first flow path being arranged such that, in use, material is caused to flow downwardly without interruption along the length of the first flow path from the inlet to the outlet, the first flow path being provided with a set of spaced stations through which the material is caused to pass sequentially in passage from the inlet to the outlet, each station having a space of reduced cross sectional area compared to the cross sectional area to each side of the station, each station having a gas inlet and a gas outlet located to each side of the space, the gas inlet of each station being connected to a source of heated gas, the gas passing through the particulate material at each station whilst the particulate material is flowing along the first flow path, the gas being substantially unreactive to the particulate material, a rate of flow of the gas through the space being controlled such that it is insufficient to cause substantial entrainment of the particulate material in the gas flowing to the gas outlet .

2. A dryer as claimed in claim 1, wherein the heat delivered to the upper most station is greater than the heat being delivered to the lower most station.

3. A dryer as claimed in claim 2, wherein the heat being delivered by the stations varies such that the amount of heat varies with the distance from the inlet.

4. A dryer as claimed in claim 2 or 3, wherein the heat delivered to each station is less than the preceding station.

5. A dryer as claimed in claim 1 or 2 or 3 or 4, wherein the heat input to each station is controlled by monitoring the temperature of the gas flowing into and/or from the space.

6. A dryer as claimed in claim 5, wherein the temperature of the gas flowing into the space is controlled by an injection means which is adapted to spray water into the -10 gas whereby the magnitude of water being sprayed into the gas is controlled according to the desired temperature of the gas to be delivered to the space.

7. A dryer as claimed in claim 5 or 6, wherein the heat input is controlled by varying the flow rate of gas through the particulate material.

8. A dryer as claimed in any one of claims I to 7, wherein space is of an annular configuration defined by an inlet manifold provided around the inner face of the first flow path and connected to the gas inlet, and an outlet baffle which accommodates the gas outlet.

9. A dryer as claimed in claim 8, wherein the inlet manifold defines an annular plenum into which the gas inlet opens wherein the lower portion of the plenum opens into the space.

10. A dryer in claimed at claim 8 or 9, wherein the outlet baffle comprises a central space closed at its upper end and open at its lower end.

11. A dryer as claimed in claim 10, wherein the upper outer surface of the baffle is configured to promote the flow of particulate material past the space, the gas outlet being accommodated with the central space.

12. A dryer as claimed in claim 10 or 11, wherein the upper outer surface of the baffle has a generally downwardly divergent configuration and the lower face of the outlet baffle is open.

13. A dryer as claimed in claim 12, wherein the outer surface of the baffle is generally conical.

14 A dryer as claimed in any one of the preceding claims further comprising a second flow path having a second inlet and a second outlet, the second inlet being connected to the outlet of the first flow path, said second flow path being generally horizontal and comprising a rotating cylindrical surface along which the particulate material is caused to pass in its passage from the second inlet to the second outlet, a - 11 heating means associated with the second flow path to heat the cylindrical surface, the atmosphere of the second flow path being substantially unreactive to the particulate material.

15. A dryer as claimed in claim 14, wherein the exhaust from the heating means is connected to the gas inlet of each station.

16. A dryer as claimed in claim 14 or 15, wherein the second flow path is provided with an exhaust adapted to enable the escape of gaseous fluids generated from the particulate material in its passage through the second flow path.

17. A dryer as claimed in claim 14 or 15 or 16, wherein the gas which is exhausted from the second flow path is utilised at least in part as the fuel for the heating means.

18. A dryer as claimed in any one of the preceding claims wherein the particulate material comprises a carbonaceous material.

19. A dryer as claimed in claim 18, wherein the particulate material comprises coal.

20. A dryer for use with a particulate material substantially as herein described.