Field of the invention

The present disclosure relates to systems and methods for cooling arid/of classifying particulate materials. The system and method have particular application in cooling and/or classifying coal products.

Background of the invention

Many particulate materials need to he cooled and classified as part of processing or prior to storage/ tran sport at ion .

Raw coal is one example of suc particulate material. It is common to process raw coal for a variety of reasons. For example, low rank coals may be upgraded before use, and/or briquettes may be formed from the raw material. Such processing may involve the application of heat to, or generation of heat within, the coal products. In order to prevent th coal products from igniting cooling may he required - for example between processing step and/or after processing but before stockpiling/transporting the end product.

In order to cool coal products vertical column coolers have been used in which air flows through a column of coal. Such coolers can, however, fail to cool the coal products evenly and hotspots in. the column of coal can occur. Further, in vertical column coolers the coal product is subjected to vertical loads that can damage the coal product a it migrates towards the bottom of the column.

Vibrating bed cooling -machines have been used for cooling small particulate products capable of being fluidized. Such systems generally include, a perforated deck which supports the particulate products, and which vibrales in order to transport the prod cts along the deck from an inlet to an outlet. A blower is provided to force/blow air or other cooling gasses through the bottom of the deck and products. The combination of vibration and air flow fluidises the particulate product, thereby cooling it as it is conveyed. hi known fluid bed systems the deck is typically located in a gas-light enclosure capable of operating under pressure without fine particulate or dust escaping the enclosure. Alternatively, forced draft fans and induced draft fans have to be carefully configured in order to maintain balanced air flows. Both of these approaches introduce complexity and cost in the .manufacture and maintenance of such systems. Further, use o an enclosed and pressurised fluid bed system increases the risk of dust explosion for explosive materials such as coal.

Reference to any prior art in the specification is not an acknowledgment or suggestion that thi prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded a relevant, and/or combined with other pieces of prior art by a skilled person in the- aft.

Summary of the invention

In one aspect the present invention provides a system for cooling particulate- material, the system including: a deck having openings therein; a chamber partially defined by and located above the deck; a vibration system for vibrating the deck to move particulate material received on the deck through the chamber towards a deck outlet; a gas extraction system for extracting gasscs from the chamber, thereby inducing an airflow through the openings in the deck and the particulate material supported b the deck, the induced airflow through particulate material serving to cool the particulate material; and an air inle arrangement located below the deck and through which air is drawn.

In second aspect the present invention provides a method of cooling particulate material including: receiving particulate material onto a deck within a chamber, the deck having openings therein; operating a vibration syste to vibrate the deck to cause the particulate material to move through the chamber along the deck towards a deck, outlet; operating a gas extraction system to extract gasses from the chamber by drawing air out of the chamber, thereby inducing an airflow from an air inlet arrangement through the opening in the deck and the particulate material supported by the deck and. the induced airflow through particulate material -serving to cool the particulate m ateri al .

Furthe aspects of the present invention and further embodiment of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. Brief description of the drawings

Figure 1 is a side schematic view of a system for cooling and classifying particulate materials in accordance with an embodiment of the invention;

Figure 2 is the side schematic view of Figure 1 with the near side wall removed;

Figure 3 is a top schematic view of the system depicted in Figures 1 and 2;

Figure 4 is a top view of a deck for use with the system of Figures 1 to 3 in accordance with one embodiment of the invention;

Figure 5 is a top view of a deck for use with the system of Figures 1 to 3 in accordance with a still further embodiment of the invention;

Figure 6 is a side schematic view of a system for cooling and classifying particulate matter in accordance with a further embodiment of the invention; and

Figure 7 is a side schematic view of a system for cooling and classifying particulate matter in accordance with a still further embodiment of the invention.

Detailed description of the embodiments

Overview

The present invention provides systems and methods for coolin particulate matter. In addition to cooling, the system can be operated t classify the particulate matter into a plurality of groups of particulate material of different size ranges.

The systems and methods described herein have particular application to cooling particulate coal matter. For example, when forming coal briquettes there is typically a need to cool the coal material that has passed through the briquetting apparatus (e.g. rollers). Thi material may include fully formed coal briquettes, broken briquettes (i.e. relatively large agglomerates of different sizes), and coal dust (also made up of particles of different sizes). As used herein, and in the briquetting example, ''particulate matter' refers to the fully formed briquettes, broken o partially formed briquettes, agglomerates, and dust particles. In order to illustrate various features and aspects of the invention the following description will focus on the cooling and classification of such coal products. It will be appreciated, however, that the principles- disclosed herein may be applied to the cooling and/or classification of alternative particulate materials and products. It will be appreciated that a variety of materials can be broadly classified as "coal", such as: bituminous materials, sub-bituminous materials, lignite, anthracite.

Figure 1 is a side schematic view of a cooling system 100 in accordance with an embodiment of the invention. Figure 2 depicts the same system as Figure 1 with the near side-wall removed. Figure 3 i a top view of the system of Figures 1 and 2,

The system 100 includes a deck 102 which is provided with a plurality of through openings 103. The deck 102 extends between a deck inlet region 104 and a deck discharge regio 106. in use the system 100 (including deck 102) is vibrated by a vibration system 108 which assists in conveying/propagating particulate material 1 10 along the deck 102 in a direction of movement indicated by arrow A (the direction of movement being from the inlet region 1 4 towards the discharge region 106).

A chamber 1 12 is located above the deck 102. Chamber 112 is defined by the deck 102, sidewails 1 14, end wails 1 16, and a roof 1 18. As can be seen, sidewalks 11.4 extend below the deck 102 t meet with a floor 120 (the region bet een the deck 1 2 and floor 120 indicated by arrow D in Figure 2). In the region between the deck 102 and the floor 120 an air inlet arrangement, in this case including a plurality of air inlets 122 (discussed in detail below) are formed in both sidewails 114, through which air can be drawn into the chamber 112 (via the opening in the deck 102). In a region between th deck 102 and the roof 118 a plurality of inspection windows 124 are provided in one or both of the sidewails 1 14 allowing for inspection of the particulate material passing through the chamber 1 12 on the deck 102. While the present embodiment includes a flat floor 120, the floor could be formed by one or more chutes or smiilar for catching and directing material passing through the deck,

A ga extraction system, indicated generally by arrow 126, operates to draw gasses from the chamber 1 .12. The gas extraction causes ambient air to be drawn from the air inlets 122 through the deck 102 (and the particulate material 1 10 supported thereon). This induced airflow serves to cool the particulate material 110 during its residence time In the chamber 1 12.

The floor 1 0 of the system 100 is located below the deck 102 and serves as an underflow bed which collects underflow particulate material 110b that passes through the openings in the deck 102. Vibration of the floor by the vibrating means 1 12 conveys the underflow particulate material 1 10b along the floor 120 in the direction of travel A. Sidewalls 1 14 prevent or reduce spillage of the underflow particulate material 110b from the floor 120. To this end, the air inlets 122 are configured/positioned such that the distance- between the bottom of the air inlets 122 and the top of the floor 120 is sufficient to reduce the likelihood of material falling through the air inlets 122.

System 100 is als provided wit a plurality of particulate material outlets. These include a deck outlet 130 (in the discharge region 106) at which deck particulate material 1.10a is captured (i.e. deck particulate material 1 10 a of a first size range), and one or more of underflow outlets 132 at which underflow particulate material 1.10b is captured (i.e. underflow particulate material 110b of one or more additional size ranges). The underflow material at each outlet 1.32 may be captured via a chute or similar directing the underflow material into a catchment, or a further conveyer belt system to convey the underflow material to a desired location. Further, the gas extracted from the chamber 1 12 by the gas extractio system 126 typicall has entrained particulate material 1 1.0c (e.g. dust particles of a further size range) which is captured at a gas particle separation system 134 (shown in Figure 3).

Parts of the system 100 will now be described in detail.

Inlet region 104

The inlet region 104 provides a catchment for incoming particulate material 1 10. As per the briquette example discussed above, the particulate matter 1 10 may include particles or agglomerates of different, size (e.g. full briquettes, partially formed or broken briquettes of differing sizes, and dust particles of differing sizes).

Incoming material 1 10 may be fed to the inlet region 104 (which may be a trough, or similar) by a conveyor, feed hopper or other means (not shown). From the inlet region 104 the particulate material 1 10 is introduced to the deck 102 by the vibration of the deck 102 and/or inlet region 104, a slope of the inlet region 104, and/or the pressure of additional particulate material 3 10 being introduced into the inlet region 104.

In order to control the admission of the particulate material 1 10 onto the deck 102 an inlet control 136 (which can be seen in Figure 2) is provided. In this case the inlet control .136 is a knife gate movable up and down so a to define an inlet ga between the bottom, of the gate and the to of the deck 102. By adjusting the inlet control 136 the depth or thickness of the particulate material 110 on the deck 102 can be controlled. As discussed further below, the depth of particulate material 1 10 impacts on the rate at which the material 1 10 cools and, accordingly, the desired airflow and re idence time of the particulate material 1 10 in the chamber 1 12.

Alternative inlet controls 136 are, of course, possible. For example, the inlet control 1.36 ma be an adjustable flap, a plurality of different: sized doors, or suchlike. Further alternatively, admission of the particulate material 1 1.0 from the inlet region 104 to the deck 102 may be- through an opening of a fixed size, dimensioned to provide a fixed layer thickness.

Deck 102

The deck 102 will now be described with reference to Figures 4 and 5.

Generally speaking the deck 102 extends the length of the chamber 1 12. The deck 102 includes a number of openings which are sized to allow particulate material of one or more desired underflow size ranges (i.e. underflow particulate material 1 10b) to pass through the openings and be caught by the floor 1 0.

As discussed above, in use the vibration system 108 vibrate the system 100 (including the deck 102) on driving springs 138, which move the deck 102 (and floor 120) essentially back and forth at the angle defined by the springs 138 (indicated by arrow E). This vibration assists in the distribution of the partieiilate material on the deck 120 (and floor 120), and in moving the particulate material 110 along the deck 102/floor 120 in the direction of movement A.

The general movement of the particulate material 110 in the direction of movement A may also be assisted by the flow and pressure of further particulate material 1 10 through, the inlet regio 1 4, In addition, the deck 102 (and/or the floor 120) may be angled to provide a slope towards the discharge region 106 to assist the flow of particulate material 1 10 in the direction o movement A. in some embodiments, the deck 102 is an apertured deck formed of a solid material with apertures therein. For example, the deck 102 may be formed from one or more metal sheets with openings/apertures created by mechanical means (such as stamping, machining, drilling, etc), laser cutting, or water jet cutting, or other appropriate means. As the particulate material 1 10 passes over the apertures any particulates having a sufficiently small siz (and appropriate shape) with respect to the size of the apertures fall (or are vibrated) through the deck 102 to be caught in the floor 120. Apertiired decks of this type can, however, be subject to blinding - i.e» particulates getting caught in the apertures to an extent tha they are stuck and not dislodged by the vibration of the deck 102, When blinding occurs, the passage of both particulate material and airflow through the blinded apertures is prevented or reduced, degrading the operational performance of system 100 and requiring manual cleaning.

To avoid o reduce the likelihood of blinding, the deck 102 in accordance with one embodiment of the invention is ripple wire construction (or self-cleaning screen/non-blinding screen construction). By way of non-limiting example, ripple wire as manufactured/supplied by The Locker Group, Candurs, Juda Wire Cloth. Nepean Rubber may be appropriate. In certain cases a deck constructed of H-Mesh wit a relativel wide open area ma he particularly appropriate for handling initiall moist and wet material.

Figure 4 illustrates one example of a ripple wire deck 400. Figure 4 shows the complete deck along with a magnified section. Deck 400 includes a plurality of wires 402 (the wires together defining a solid surface are of the deck 400) which define openings 404 between them (the openings together defining open surface area of the deck 400). Each wire 402 in the deck 400 i stretched across the deck 400 in a direction generally perpendicular to the direction of movement A in a rippled (in this case zig-zag H-Mesh shape opening) pattern,

The arrangement of the wires 402 in deck 400 is such that as the deck 400 is vibrated the separation distance between the wires 402 (i.e. the openings 404) expands and contracts, This assist in avoiding or reducing blinding, as particulate material that could become stuck in the openings 404 is vibrated through the openings 404 as they expand during vibration.

By way of further alternative, the deck 102 (or sections thereof) may be formed by a plurality of straight wires running parallel to each other and extending between the sides of the cooling system 100 (i.e. transversely to the direction of travel of material through the coolin system 100). In this case the openings in the deck 102 are defined by the gaps between adjacent wires,, and as with the example of Figure 4 the separation distance between adjacent wires expands and contracts with vibration of the deck to allow material through. Figure 5 is a schematic top view of a deck 500 in accordance- with a further alternative embodiment of the invention. Figure 4 shows the complete deck 500 together with magnified sections. Deck 5.00 includes a plurality of different deck sections 502, in this case a first deck section 502a, a second deck section 502b, and a third deck section 502c. Each of the deck sections 502 is defined by wires 504 (as per the embodiment of Figure 4), however in deck 500 the openings 506 defined between adjacent wires 504 in each deck section 502 get progressively larger along the length of the deck 500 (in the direction of movement A). For example, the openings 506a of deck section 502a (which is positioned proximate the inlet region 1 4) are smaller than the openings 506b of deck section 502b (which is positioned between the first section 502a and the third section 502c), and the openings of the deck section 502b are smaller than the openings 506c of the third deck section 502c (which is located proximate the outlet area 106).

The ends of the different deck sections 502 (being the regions of the deck sections the furthest along the direction of movement. A) approximately align with the underflow outlets 132: i.e. the end of the first deck section 502a is approximately aligned with the first underflow outlet 132a, the end of the second deck section 502b is approximately aligned with the second underflow outlet 132 , and the end of the third deck section 502c is approximately aligned with the third underflow outlet 132c. As discussed below, using deck with section having differently sized openings allows for further classification of the underflow particulate material 1.10b into groups of different ske ranges.

Deck 500 is depicted as a ripple wire deck simi lar t deck 400, howe ver could, of course, be an aperturcd deck or grating with apertures becoming progressively larger along the length of the deck. Similarly, while three deck sections 502 are shown and discussed, more or fewer deck sections could he used to classify the particulate material 1 1 into more or fewer underflow size ranges.

Outlets

As described above, and with reference to Figures .1 and 2, system 100. includes a plurality of particulate material outlets at which groups of particulate material of different size ranges can be captured: the perforated deck outlet 130 and underflow outlets 132a. 132b, and 132c. The gas particle separation system 134 (discussed in further detail below) provides a further particulate material outlet at which an additional group of particulate materia! of a further different size range can be capt red.

The deck outlet 130 provides a means for deck particulate material J 10a (i.e. particulate material that does not fall through the deck 102 or become entrained in the gas flow) to exit the deck 102 and be captured. The deck outlet 130 includes a chute or ramp 140 providing a downward slope from the deck 102 to a catchment area (in this case a conveyor 1.42 where the deck particulate material 5 10a is transported away from system 100 for further processing, storage, or transportation), in this case the angle of the downward slope is 45 degrees, however angles within the range of 20 to 90 degrees may be appropriate. Providing the discharge chute with an angle of less than 90 degrees results in material discharged from the deck outlet 130 having a horizontal component rather than a straight vertical drop from th deck 102. This can b advantageous in reducing damage or breakage of the particulate material (which may, for example, be whole briquettes) exiting the deck 102.

Upstream of the deck outlet 130, the endwall 1 16 is fitted with a curtain 144 made of resilient material (e.g. rubber). The curtain 144 acts as a flap over the openin of the discharge chute 140, which reduces air being drawn into the chamber 1 12 via the discharge chute 140. This is advantageous as the ga extraction system 126 creates a partial vacuum (or reduced pressure compared to ambient air pressure) inside the chamber 1 12 in order to induce airflow through the deck 102, The induced airflow through the deck 102 is maximised by reducing the ingress of air into the chamber 1.12 from any sources other than through the deck 102 (e.g. in this case by reducing the ingress of air through the discharge chute 140).

Underflo particulate material 1 10b that passes through opening in the deck 102 is initially captured in the floor 120. in contrast with th deck 102. the floor 120 has (for the most part) a solid base to hold tire underflow particulate material 1 10b. The side walls 1 4 extending from the floor 120 form a trough to hold the underflow particulate material 110b. As noted above, the sidewalls have a minimum height at the air inlets 122, being the heigh between the (Op of the floor 120 and the bottom of the air inlets 122. The air inlets 122 are designed so as to maximise the surface area of the inlets 122 whilst providin a minimum height that prevents underflow particulate material 1 10b (or at least a significant amount thereof) from escaping through the air inlets 122 followin accumulation of excessive amounts of these fines (bearing in mind that the vibration of the floor 120 causes movement of the particulate material). Spaced along the floor 120 are underflow outlets 1.32. In the present embodiment three underflow outlets 132a, 132b, and 132e are provided which, as discussed above, approximately align with the ends of the three deck section 502a, 502b, and 502c respectively. The undeif low outlets 132 allo underflow particulate material that has passed through the relevant deck section 502 to exit the floor 120 for capture. In the present embodiment the underflow outlets 132 are slots/openings acros the floor 120 through which the underflow particulate material 1 10b- Mis into a chute or hopper or similar (or onto a conveyor) for collection.

The underflow outlets 132a, 132b, and 132c are provided with underflow outlet closures 146 (146a, 146b, and 146c respectively) which allow the underflow outlets 132 to be selectivel opened o closed, In the present embodiment the underflow outlet closures 146 are knife gates (als referred t as slid gate or gate valves). Where an. underflow outlet 1.32 is closed by its ciosure 146, the underflow particulate material 1 10b continues past the relevant outlet towards the next outlet 132. For example, if underflow outlet 132a is closed by closure 146a, particulate ^■ material, progresses along the floor 120 to the next underflow outlet 1 2b (which, of course, may also be closed). This allows operators to select the ske classification of the underflow particulate material to be collected.

A final underflow outlet 148 is provided downstream of underflow outlet 132c at which any underflow particulate material 1 10b in the floor 120 that has not been collected at upstream underflow outlets 132 exits the floor 120 for collection.

In some embodiments, underflow partitions (not shown) may be provided to prevent (or at leas minimise) underflow particulate material 1 10b from progressing beyond an underflow outlet 132, Where provided, such partition may be removable depending _, on the operator's requirements.

It will be appreciated that fewer or additional underflow bed outlets 132 may be provided. For example, the final underflow outlet 148 in the discharge region 106 may be the only underflow outlet, with all underflow particulate material 1 10b being conveyed/propagated (by vibration) to that single outlet. In this instance, a three-way classification of particulate material is achieved by the system; the underflow particulate material 1 10b that passes through the deck 102, is caught in the floor 120, and is captured a the single underflow outlet; entrained particulate material 1 1.0c that is entrained in the induced airflow and captured in the gas/particle separation system 134; and deck particulate material 11 ()a that s conveyed to the end of the deck 102 and captured at the deck outlet 130.

Alternatively, additional underflow bed outlets 132 may be provided. Additional outlets 132 may either align with deck sections 502 having different sized openings (allowing for further classification of the particulate material 110 into different size ranges) or may simply be provided as additional capture points from the floor 120 to reduce the likelihood of the floor 1.20 overflowing.

Gas extraction system

The gas extraction system 126 will now he described with reference to Figures 1 to 3.

The gas extraction system 126 includes a plurality of exhaust openings 150 in the roof 1 18 of the chamber 112. Each exhaust opening 150 is connected to a main exhaust duct 152 via a secondary exhaust duct 154. The main exhaus duct 152 leads to the gas/particle separation system 134. upstream of which is an extraction fan 156. Extractio fan 156 operates to draw air (together with entrained particulate- matter 1 10c) out of the chamber 1 12 through the exhaust openings 150, secondary exhaust ducts 154, main exhaust duc 152, and gas/particle separation system 134. Drawing gasses out of chamber 112 in turn induce the flew of air into the system 100 through the air inlets 122, the openings in the deck 102, and through the particulate material 1 10 on the deck 102, thereby cooling the particulate material 1 10.

The air (and any entrained particulate material 110c) extracted from the chamber 1 12 are drawn throug gas/particle separation system 134 which operates to separate entrained particulate matte 1 10c. As will he appreciated, a variety of gas/particle separation systems may be used- for this purpose, for example a filter arrangement, haghouse, scrubber,- cyclonic separator, or other appropriate particulate/air separation system. Entrained particulate matter 110c separated from the gas and captured in the air/particle separation system 134 can be collected for further processing or use. In the illustrated embodiment, a single gas/particle separation system 134 is positioned upstream of secondary exhaust ducts 154 and downstream of the extraction fan 156. In alternative embodiments additional air/particle separation systems may be provided, for example where each secondary exhaust duct 354 meets the main exhaust duct 152. in order to cool the particulate material. 1 10, it is advantageous to have the airflow through the deck 102 uniform (or close to uniform) alon its length, To achieve this, in the embodiment of Figures 1 and 2 the air inlets 122 on a given sidewall 114 have a combined length that is a large proportio of the total lengt of the chamber 1 12 (the length being the same dimension in which the particulate material 1 10 is moved through the chamber 1 12). I addition, the air inlets 122 on given sidewall define a relatively large combined air inlet surface area proportionate to the closed surface- area of the sidewalls 114 below the deck 102. This i in contrast to the air inlets of "normal" vibratory cooling systems which are typically square/eireular/squat rectangular inlets of a relatively small surface area compared the closed sidewall surface area below the deck, and a relatively small combined length compared to the length of the chamber.

In the embodiment of Figures 1 to 3, the relatively large combined air inlet surface area (or relatively large combined air inlet length) is achieved by providin three air inlets 122 on each sidewall 1 14, each air inlet 122 being elongate i shape and relatively long and the three air inlets 122 bein relatively evenly spaced along the length of the sidewall 1 14. This provides the air inlets 1 2 on each sidewall 1 14 with a large combined air inlet surface area when compared to the closed surface area of the sidewall below the deck 102, and a relatively long combined length relative t the length of the chamber 1 12. For example, the combined length of the air inlets 122 on each sidewall may be greater than or equal to 50% of the length of the chamber 122, greater than or equal to 55% of the length of the chamber 122, greater than or equal to 60% of the length of the chamber 122, or greater than or equal to 65% of the length of the chamber 122.

Alternative embodiments within the scope of the invention are, of course possible.

Generally speaking the closed surface area below the deck is relevant only in order to provide structural support to the system 100. Relevantly, the ratio of the open surface area below the deck 102 (i.e. the surface area of the air inlets 122) to the surface area of the deck 102 within the chamber 1 12 should be selected to provide for an even distribution of air through the deck 102. In one particular embodiment the total open area of the air inlet 122 (i.e. the one combined area of the inlets on both sidewalls) is approximately 1.6 square meters and the surface area of the deck 102 inside the chambe 112 is 13.5 square meters - providing for a ratio of 0.12. Suitable ratios, however, may range from around 0.1 to around 0.15. The air inlets 122 should be relatively evenly spaced along the length of the deck 102 to provide a relatively even airflow along the length of the deck 102.

In an alternative way of considering an aspect of the invention, the size o the air inlets 122 should be selected so that an adequate air velocity exists through the air inlets 122 to create adequate turbulence for screening underflow fines cooling in the floor 120, as well as an adequate horizontal flow vector to distribute air over the width of the deck 102. In this case the targeted velocity through the slots should be greater than 2 rn/s in order to maintain a Reynolds number of greate than 4000 (turbulent region). Too low a velocity could result in hot fines not cooling down, particularly towards the middle of the chamber 1 12. Conversely, too high a velocity could create an excess pressure drop with higher fan power consumption.

By way of further illustration, Figures 6 and 7 depict alternative embodiments of cooling and classification systems 60 and 700. Systems 600 and 70 are the same or similar as system 100 described above, with the exception of the air inlets.

In system 600, each side wail 114 below the deck 102 is provided a single air inlet 602 extending the length of the chamber 1 12. This provides the air inlet 60 on a given side wall 1 14 a total length that is a relatively large proportion (nearly 100% or 100%) of the length of the chamber 1.12. In this embodiment the sidewalls 114 do not provide structural support for the deck 102 (or other system components) which is instead provided by alternative means such as a framework or similar (not shown).

In system 700, each sidewaU 1 14 below the deck 102 is provided with a large number of air inlets 702. While each individual air inlet 702 is relatively small, the combined length of the individual air inlets 702 on a given sidewall is a large proportion of the total length of the chamber 112. and the air inlets 702 are evenly spaced along the length of the chamber 1 12.

An additional advantage of the induced airflow arrangement provided by embodiments of the present invent on is that air inlets 122 (or 602 or 702) can simply be open to atmosphere. This is in contrast to known forced airflow/coolant gas systems where the air inlets need to be fitted with flanges or other connecting formations in order to connect ducting through which the air can be forced. To further control the airflow through system 100, and returning to Figures 1 and 2, exhaust dampers or valves 1.5.8 are provided on each of the secondary exhaust due s 154. Each exhaust valve 358 in this instance is a knife gate valve which can be positioned to completely open the relevant secondary exhaust duct 154 (allowin 100% airflow through the duct 154), completely close the relevant secondary exhaust duct 154 (allowing 0% airflow through the duct 154), or partially open the relevant exhaust duct 154 (allowing partial airflow, between 0- 100% airflow through the duct .154). The exhaust valves 158 allow adjustment of the gas flow rate, velocity, and/or pressure in the chamber 2.

The exhaust valves 158 are independently adjustable to allow adjustment of the flow of drawn gases in the zones proximal to the respective exhaust outlets 150. By adjusting the exhaust valves 15 an even velocity profile can be maintained from a fugitive fines removal point of view.

The embodiments described above teach system 100 in which the airflow is induced through the deck 102 and chamber 1 12. In certain circumstances, such an induced airflow arrangement is advantageous to a forced airflow system in which air (or other cooling gasses) is forced though the deck 102 and chamber 1 12. Forcing air or other cooling gasses into system 100 (e.g. by blowing it through air inlets 122) can cause fine particulate material (e.g. dust) to be blown around the area under the deck 102, the chamber 1 12, and out of the. chamber 112 at the inlet region 104 and/or discharge region 106 if the forced airflow system i not equipped with an induced draft fan to avoid pressure build-up inside the unit. In contrast, the present disclosure teaches drawing gasses from the chamber 112, which induces the flow of air (or other cooling gasses) at ambient pressure to enter through the air inlets 122 and deck .102. Furthermore, as the pressure inside the chamber 112 is lower than the atmospheric pressure, ambient air i more likely to be drawn into the chamber 112 at the inlet region 104 and discharge region 106, rather than being blown out of the chamber 1 12 at those regions.

Further, forcing/blowing air or cooling gasses into the system 100 would require compressing the air/gas or passing the air/gas through moving machinery such as an impeller. This can heat u the air/gas - albeit marginally - and can reduce its effectiveness at cooling the particulate material.

Vibration system The vibration system 108 may be any known system for causing appropriate vibration in the system 100 (including deck 10 ^* 2 and floor 120) to move material forward at the required pace (e.g. less than lm per minute).

In the present embodiment the vibration system 108 is supported from the ground by spmng oscillating mounts 160. An electric rotary motor 162 driving out of balance weights vibrates the system 108 which, through drive springs 138, vibrate the deck 1.02 and floor 120.

Drive springs 138 are: selected appropriately t support the weight of the system 100 and material. Vibration amplitude and/or frequency can be adjusted in order to alter the material displacement speed.

System and operational parameters and considerations

As will be appreciated the specific parameters of the system 100 and its operation will depend on the particulate material being cooled and/or classified, its temperature on introduction into the system 100, and the desired temperature of the material exiting the system 100,

For example, in the briquette scenario discussed above, after coal briquettes are formed they may be at a high temperature and require cooling. The particulate matter 110 fed into the system 100 at inlet region 104 includes whole briquettes, partially formed or broken briquettes (of varying si es), and coal dust (also of varying sizes). The average temperature of the particulate material 1 10 may be between 90 to 150 degrees Celsius. To ensure the particulate material 11 is safe for handling, the aim is for it to be cooled to 50 degrees Celsius or less. The variables that influence this cooling include: the residence time in the chamber 112; the depth of the particulate material 1 1 on the deck 102; the temperature of the incoming air/cooling gases (via air inlet 122); the volume and velocity of the airflow through the deck 102 and particulate material 1 10; the size of the particulate material; and the overall surface area the particulate material presents for cooling.

To achieve the desired cooling, the following system and operational parameter may be defined/adjusted: the length and width of the deck 102; the open surface area of the deck (defined* e.g., by the opening 404 in the deck 400); the depth of particulate material on the deck 102 (controlled by inlet control 136) the approximate volume/velocity of the induced airflow through deck 102; the residence time of the particulate material 110 in the chamber 112 (controlled by operation of vibration system 108); the temperature of the air/cooling gasses introduced through air inlets 122.

In addition to configuring operating the system 100 to achieve the desired cooling, system 10 is also configured/operated to achieve the desired classification of the incoming particulate materia! 110. This is determined by the size (or sizes) of the openings in the deck 102 (which determines the size range or size ranges of underflow particulate material. 110b) and the velocity of the induced airflow (determining the si¾e of particulates that are entrained in the airflo - i.e. the size range of the entrained particulate material i 1.0b).

With respect t the entrained particulate material 1 10b, coal fines/dust of less than or equal to 0.5mm can easily become airborne and be a. nuisance and/or hazardous. As such, the separatio and collection of such particles from the incoming particulate material 1 10 is desirable. This is achieved in system 100 by providing a airflow velocity through the deck 102 sufficient to entrain coal particles (dust) less than or equal to 0.5mm in size. An. airflow velocity of between 1 to- 2 meters pe second will typically be suitable to achieve this within the broader context of needing also to cool the incoming particulate material 110, An airflow velocity of lower than 1 m s may not provide adequate cooling of the particulate material 110 at an efficient rate (i.e. for a given residence time) _* Alternatively, a velocity of greater than 2 m/s may result in particles larger than those desired becoming entrained.

In addition, in order to safeguard against explosive combustion it is desirable to keep the concentration of dust entrained in the airflow and drawn into the gas extraction system 126 at a. concentration of less than 25% of the Minimum Explosive Concentration (MEC). The MEC may be measured or calculated for the particular product being cooled/classified. To keep the concentration of entrained particulates below 25% of the MEC, air flow through the chamber 1 12 and the gas extraction system 126 should be maintained at above a minimum flow rate. That is, greater airflow reduces the concentrat on of entrained particulate (assuming other parameters are adjusted so that the greater air flow does not cause changes in ai velocity and/or turbulence that generate significantly more dust).

The size or sizes of the openings in the deck 102 are also selected to allow particulate material of one or more desired size ranges to pass through the deck 1 2 to the floor 120 for collection/classification as required. This may include selecting a deck 102 (or sections 502 of a deck) with opening size or sizes t allo particulates of smaller tha a selected si/e to pass through.

In one embodiment, suitable for use in coolmg/classifying the output of a briquetting process as discussed above, wires 402 of approximately 1 ,6m:m in diameter are used, and which have a separation distance/spacing of approximately 3mm betwee adjacent wires 402. Such an arrangement allows for underflow particulate material 11.0b of approximately 3mm and under to pass through the deck 400. In this case (i.e., a deck 400 with the same sized openings 404 along its length) the incoming particulate material is classified into three size groups: entrained particulate material 11.0c having a size range of approximately 0,5mm and under; underflow particulate material 1 10b having size range of between approximately 0.5mm. to 3mm; and deck particulate material 1 1 a having a size range of approximately 3mm and above. Deck with larger openings can be- installed to effect size separation a needed.

Alternative opening size or sizes may, of course, be used in order to obtain different or additional classification groups _* By way of one example, a separation distance of approximately 6mm between adjacent wires 402 may be used in order to allow for underflow particulate material 1 10b of approximately 6mm and under to pass through the deck 400. In adjustin the deck opening size or sizes, consideration should be had to the impact of the deck openings (i.e. the ratio of the closed deck area to the open deck area) on the airflow that is to be induced through the deck 102.

The airflow through the deck 102 (which, absent some losses would approximate airflow through the gas extraction system 126) may be calculated according to the formula:

Airflow (trr/s) - Open surface area of deck (m ² ) x Velocity of gas (m/s)

Therefore,.

Velocity of gas - Airflow / Open surface area of deck

As discussed above, the velocity of gas is suitably between 1 to 2 m/s. Thus given particular open surface area of the apertures, the required airflow range may be calculated in accordance with the above formula.

Example By way of specific example, configuration and operation of system 100 for cooling and classifying particulate coal product at a rale of 10 and 20 tonnes per hour may include the following features, specifications and operating parameters:

• Incoming gas (via ai inlets 122): o Ambient air at a temperature of up to 30 degrees Celsius and at atmospheric pressure.

• Particulate coal product: o Fully formed coal briquettes, partially formed and broken coal briquettes, and coal particles/dust, at a temperature of between 90 to 150 degrees Celsius. The size of the briquettes will depend of the pocket size of the briquette rolls, but will typically be larger than around 25mm.

• Deck specifications (ripple wire construction): o Wire diameter approximately 1.6mm. o Wire separation approximately 3mm between centres of adjacent wires, o Total surface area:

^■ 1 nrT for 10 tonne/hour

^■ 27 in ^* for 20 tonne/hour o Open surface area of deck: 43% to 5.0% of the total deck surface area

• Classified products: o Coal briquettes/agglomerates that exit the deck outlet 130: greater than approximately 3mm. o Particulate coal material, passing through the deck and being collected from one of the underflow outlets 132 or the final underflow outlet 148: between approximately 0.5mm to 3mm. o Particulate coal materia), (dusts/fines) entrained in the gas stream and collected from the separation system. 134; less than or equal to 0.5 ram,

• Residence time: o As described above, the required residence time for particulate matter inside the cooling chamber will depend on a. number of parameters, such as; the initial temperature of the particulate matter; the ambient temperature/temperature of the air being drawn through the cooling chamber; the desired temperature for particulate matter exiting the cooling chamber at deck outlet 130; the depth of materi l on the deck.

"Residence time ^' ' in this sense refers to the average residence time of particulate matter that travels the entire length of the deck and is collected at the deck outlet 130.

For example, the system may be operated such that the average residence time inside the cooling chamber is. around (or at least) 10 minutes for coal briquettes/agglomerates ^' to allow for cooling to less than 50 degrees Celsius for particulates collected at the deck outlet 130.

Longer residence times, such as 15 minutes, will achieve more cooling of the product.

Alternatively, shorter residence times (e.g. 5 minutes) may be appropriate where the initial temperature of the material is lower, the ambient temperature is lower, and/or the desired final temperature of particulate material at deck outlet 130 is higher.

• Velocity of air through the openings of the deck: o Between 1 to 2 m/s o Preferably between 1.5 t 1.8 m s

» Induced airflow o Typically around 10 nrVs when operating at 10. lonn.es/hour. This can be calculated by the above mentioned airflow formula with the following parameters:

^■ Total surface area of deck of 13.5 m ³ ;

^■ Average of 46.5 % open surface area t the total surface area of the deck;

^■ Average velocity of air through the apertures at 1.65 m o 20 nrVs hen operating at.20 tonnes/hour.

It will be understood that the invention disclosed and delined in this specification extends t all alternative combinations of tw or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.