GB2561848A

GB2561848A - Waste disposal apparatus

Info

Publication number: GB2561848A
Application number: GB1706489.0A
Authority: GB
Inventors: Spencer Nik; Jouhara Hussam
Original assignee: MANIK VENTURES Ltd
Current assignee: MANIK VENTURES Ltd
Priority date: 2017-04-24
Filing date: 2017-04-24
Publication date: 2018-10-31
Also published as: GB201706489D0

Abstract

A waste disposal apparatus comprising a heat treatment chamber for processing waste at an elevated temperature, the chamber having a vent leading to a scrubber 36 via a heat exchanger. The scrubber comprises a disrupted flow path with at least one nozzle 54, 56, 58, 60 directed towards the disrupted flow path and a supply of liquid to the/or each spray nozzle. Preferably the flow path is disrupted by at least one baffle plate 48 and ideally by two or three baffle plates 50, 52. The waste disposal apparatus may further comprise a drain 64 allowing escape of the liquid from the scrubber. Ideally the drain comprises a conduit that extends upwardly through the floor with an open end standing proud of the floor by a preset distance. Optionally the flow path includes at least one filter. Preferably the scrubber comprises a housing divided longitudinally by a dividing wall, the housing having an inlet located on one side and an aperture in the dividing wall wherein the inlet receives gas flow from the vent and the filter is located on the opposite side of the dividing wall.

Description

(54) Title of the Invention: Waste disposal apparatus Abstract Title: Waste disposal apparatus (57) A waste disposal apparatus comprising a heat treatment chamber for processing waste at an elevated temperature, the chamber having a vent leading to a scrubber 36 via a heat exchanger. The scrubber comprises a disrupted flow path with at least one nozzle 54, 56, 58, 60 directed towards the disrupted flow path and a supply of liquid to the/or each spray nozzle. Preferably the flow path is disrupted by at least one baffle plate 48 and ideally by two or three baffle plates 50, 52. The waste disposal apparatus may further comprise a drain 64 allowing escape of the liquid from the scrubber. Ideally the drain comprises a conduit that extends upwardly through the floor with an open end standing proud of the floor by a preset distance. Optionally the flow path includes at least one filter. Preferably the scrubber comprises a housing divided longitudinally by a dividing wall, the housing having an inlet located on one side and an aperture in the dividing wall wherein the inlet receives gas flow from the vent and the filter is located on the opposite side of the dividing wall.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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-1Waste Disposal Apparatus

FIELD OF THE INVENTION

The present invention relates to apparatus for disposal of waste, especially refuse from domestic dwellings and smaller commercial establishments.

BACKGROUND ART

The domestic households of the United Kingdom collectively generate approximately 30 million tonnes of waste per year. Typically, 40% of this is recyclable - such as paper, cardboard, glass, cans plastics and (in some cases) green waste and food waste. This waste is collected from the majority of households via a kerbside type collection scheme operated by or on behalf of local government bodies. Existing UK practice is to require householders to divide waste into separate containers for the various types of recyclable waste, to allow these to be harvested with the remainder being classed as residual waste. The waste is collected either weekly or fortnightly, and the residual waste is either landfilled or sent to large scale Energy from Waste plants to generate electricity.

The current approach is that waste is collected in Refuse Collection Vehicles (RCV) and disposed of through large-scale Energy from Waste (EfW) incinerators or Mass Burn Incinerators (MBI). These can process circa 200k to 300k tonnes of waste per annum. These MBIs use existing proven technology which makes them attractive to the financial markets to fund the capital cost of the plant when combined with long term waste disposal contracts with the County Councils who are responsible for the disposal and treatment of waste generated by their residents.

-2On the fringes there are alternative thermal treatment technologies emerging, such as gasification, pyrolysis and plasma, which effectively break down the waste to a synthesised gas (Syngas) and fuel product. The gas and oil can then be utilised to run electrical generating equipment. These technologies are still in their relative infancy but do have substantial environmental benefits; they are cleaner than the conventional incinerators and although smaller than MBIs their capacity is still substantial, circa 15k to 30k tonnes per annum. However, it is not yet clear that these units will be able to scale their capacity up to a commercially viable size.

Our earlier application W02015/104400A1 proposed an alternative arrangement, that instead of seeking to scale up the alternative thermal treatment technologies, they should be scaled down in order to provide a unit small enough to be accommodated near to or even within the domestic or commercial premises that is generating the waste. This would avoid the need for fleets of RCVs, avoid the planning difficulties inherent in finding locations for large waste processing plants, and allow the syngas and other pyrolysis products to be used to heat the premises in question. Our application proposed a design for such a unit.

SUMMARY OF THE INVENTION

The thermal treatment techniques are very clean, and the byproducts consist mainly of the metal content of the input rubbish, which can be recycled in the usual way, and a fine ash that is sufficiently inert to be disposed of in the premises' waste water outlet. However, the high temperature at which the process takes place and the need to exhaust the atmosphere within the treatment chamber means that some of that ash will become entrained in the exhaust air plume, i.e. as smoke.

The present invention therefore provides a waste disposal apparatus comprising a heat treatment chamber for processing the waste at an elevated temperature, the chamber having a vent leading via a heat exchanger to a scrubber comprising a disrupted flow path, at least one spray nozzle directed towards the disrupted flow path, and a supply of water to the or each spray nozzle. In this way, the entrained ash or other non-gaseous material such as oils can be efficiently removed from the exhaust air, allowing it to be vented, and the captured ash or oils etc. disposed of via a waste water outlet together with other washed discharges (e.g. ash, char or oils).

-3The scrubber works more effectively when the temperature of the exhaust plume is below around 100 °C, and preferably between about 25 and 35 °C. Thus, before it reaches the scrubber the exhaust plume is passed through a heat exchanger, i.e. an element capable of removing heat from the exhaust plume by transferring (or exchanging) it to another media. Preferred forms of the heat exchanger can provide a synergistic effect in that they both cool the plume and also extract energy that can be used for other purposes rather than being wasted in heating waste water produced by the scrubber. For example, the heat exchanger could be a radiator and the useful energy could be used for space heating. Alternatively, the heat exchanger could deliver the heat to a supply of hot water for the premises, either for sanitary use or for space heating purposes. The heat exchanger could alternatively be a direct or any other indirect contact heat exchanger.

The flow path can be disrupted by at least one baffle plate. This can be placed in a position which interrupts the flow path, forcing the flow to divert around the baffle plate. At this point, the flow speed will be reduced, so we prefer that the spray nozzle is located above and in front of the baffle plate. Ideally, the flow path is disrupted by several baffle plates, such as two or three, and a spray nozzle is located above and in front of each baffle plate. These can be arranged to define a circuitous path around the baffle plates which the airflow must follow.

Some thought should be given to allowing escape of the water sprayed by the spray nozzles. This can be assisted by spacing the lower edge of each baffle plate from the floor section of the scrubber, along at least a part of that edge. Water will then be able to flow past the baffle plates to escape via (for example) a drain outlet. To prevent these spaces allowing an alternative flow path for the air, the drain can be set at a level which is a preset distance above the internal level of the floor, and the lower edges of the baffles spaced from the floor by distances that are alternately greater than and less than the preset distance, with the baffles whose lower edges are spaced from the floor by less than the preset distance having an upper edge that is spaced from a roof section of the scrubber along at least a part of that upper edge. Thus, a circuitous path will be created alternately above and below the baffle plates, bounded at the top by the roof section and at the bottom by the level of the water which cannot escape via the drain. Such a drain might comprise a conduit that extends upwardly through the floor, with an open end standing proud of the floor by the preset distance. The scrubber may be arranged so that the floor is inclined so that the drain is near

-4the lowest part of the floor. Thus water from the nozzles (along with any admixed or dissolved matter) may be directed towards the drain. Such an arrangement may avoid build-up of unwanted admixed or dissolved matter, for example oils or soot.

Generally, we prefer that the flow path is disrupted in that it does not comprise a straight line path. This can be achieved in a variety of ways, such as an alternate up/down path created by baffle plates as set out above or in other ways such as a side-to-side path or a path contained within a non-straight conduit.

The flow path also preferably includes at least one filter, as a further check against release of particulates. This is ideally located after the or each spray nozzle so as to reduce the particulate load on the filter. A convenient arrangement is for the scrubber to comprise a housing divided longitudinally by a dividing wall, the housing having an inlet located on one side of the dividing wall, and an aperture in the dividing wall, wherein the inlet receives gas flow from the vent, the disrupted flow path leads from the inlet to the aperture, and the filter is located on the opposite side of the dividing wall. This provides a particularly compact unit.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way of example, with reference to the accompanying figures in which;

Figure 1 shows a view of a waste disposal apparatus according to the present invention;

Figure 2 shows a view of the scrubber of figure 1;

Figure 3 shows a view of the scrubber of figure 3, from one end;

Figure 4 shows a section on IV-IV of figure 3;

Figure 5 shows a section on V-V of figure 3;

Figure 6 shows an end view of a first alternative form of scrubber for use with the apparatus of figure 1;

-5Figure 7 shows a section on VII-VII of figure 6;

Figure 8 shows a section on VIII-VIII of figure 6;

Figure 9 shows an end view of a second alternative form of scrubber for use with the apparatus of figure 1;

Figure 10 shows a section on X-X of figure 9;

Figure 11 shows an end view of a third alternative form of scrubber for use with the apparatus of figure 1;

Figure 12 shows a section on XII-XII of figure 11

Figure 13 shows an end view of a fourth alternative form of scrubber for use with the apparatus of figure 1;

Figure 14 shows a section on XIV-XIV of figure 13;

Figure 15 shows an end view of a fifth alternative form of scrubber for use with the apparatus of figure 1; and

Figure 16 shows a section on XVI-XVI of figure 15.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figure 1 illustrates a general layout of the waste disposal apparatus 10 according to the present invention. This comprises a frame 12 securely attached to the ground or a suitable substrate (not shown) and which supports a heat treatment chamber 14 in which the hightemperature treatment of waste is conducted in order to pyrolise or otherwise treat the waste.

The interior of the chamber is accessed via a removable lid 16 which is kept securely closed during operation by latches 18. A drain 20 at the base of the chamber 14 can be opened (selectively) to allow the interior of the chamber 14 to be flushed with water after a heat treatment. Water then escapes via a drain hose 22.

Towards the upper end of the chamber 14, a selectively-openable exhaust port 24 allows the interior of the chamber 14 to be vented after a heat treatment. A corresponding inlet (not shown) allows cool air in to displace the hot atmosphere within the chamber 14.

-6Affer leaving via the exhaust 24, the hot air enters a heat exchanger 26 which transfers the heat of the exhaust gas to water from a hot water storage tank (not shown) which is pumped to the heat exchanger via an inlet pipe 28 and back to the hot water tank via an outlet pipe

30. Thus, the process heat is reclaimed and is available subsequently in the form of a hot water supply to the premises. A condensate drain 32 for water collected within the heat exchanger from the exhaust gas is provided, and connects to the drain hose 22 via pipework 34. The cooled exhaust gases released by the heat exchanger 26 are then passed to a scrubber 36 before being released via a suitable flue.

The scrubber 36 is shown in figures 2 to 5 inclusive. It comprises a generally cuboid housing 38, on one end face of which are an inlet aperture 40 and an outlet aperture 42 arranged side-by-side in the upper part of that end face. Within the interior of the cuboid shape, a dividing wall 44 is arranged vertically in order to separate the interior volume into first and second distinct spaces, one on either side of the interior volume. Thus, the inlet aperture 40 communicates with the first space whilst the outlet aperture 42 communicates with the second. An internal aperture 46 is provided in the dividing wall 44 to allow communication from the inlet aperture 40 to the outlet aperture 42; this is located on the dividing wall 44 toward the end face of the cuboid housing 38 that is distal from the inlet aperture 40 and outlet aperture 42. Thus the communication path involves travelling from the inlet aperture 40, along the length of the first interior space, through the internal aperture 46, and along the length of the second interior space to the exhaust aperture 42.

Within the first interior space there are three internal baffle plates 48, 50, 52. The first internal baffle plate 48 extends downwardly from the upper roof section of the first interior space, proximate the inlet aperture 40, but ends short of the lower floor section of the interior space. Thus, gases entering the first interior space via the inlet aperture 40 (at the upper end of the housing 38) must first travel downward in order to pass under the first baffle plate 48. The second baffle plate 50 is located after the first baffle plate 48 and also extends generally vertically, but has a space between it and both the roof and floor sections. The gap between the second baffle plate 50 and the roof section is generally the same as that between the first baffle plate 48 and the floor section and allows gases to flow past. The gap between the second baffle plate 50 and the floor section is less than that between the first baffle plate 48 and the floor section, and is sealed against gas flow as will be described later.

-7Finally, the third internal baffle plate 52 lies behind the second internal baffle plate 50 and, like the first internal baffle plate 48 it extends downwardly from the roof section towards the floor but with a gap between it and the floor section. The gap is similar to that that between the first internal baffle plate 48 and the floor, and more than that between the second internal baffle plate 50 and the floor. Thus, in use a gas must flow downwardly to pass below the first internal baffle plate 48, then upwardly to pass above the second internal baffle plate 50, then downwardly to pass below the third internal baffle plate 52, then upwardly to reach the internal aperture 46 and enter the second interior space.

A total of four spray nozzles 54, 56, 58, 60 are set into the roof section of the housing 38 and create a downwardly-directed fine water spray within the first interior space. They are supplied with water by a supply pipe 62. The first nozzle 54 is located above and in front of the first internal baffle plate 48, and thus creates a spray between it and the inlet aperture

40. The second nozzle 56 is located above and between the first internal baffle plate 48 and the second internal baffle plate 50, and thus creates a spray between the two baffle plates. The third nozzle 58 is likewise located above and between the second internal baffle plate 50 and the third internal baffle plate 52. Finally, the fourth nozzle 60 is located above and behind the third internal baffle plate 52. As a result, gas flowing along the circuitous path around the baffle plates is thoroughly doused with the water spray, removing smoke particulates.

Alternatively, the spray nozzles may be provided in a side section of the housing to provide a horizontally-directed fine water spray.

A scrubber drain 64 is provided in the floor section of the housing 38 and allows water from the nozzles to escape. This takes the form of a drain pipe leading to a U-bend formation 66. The drain pipe passes through the floor section of the housing 38 and has an open end 70 that is spaced from the floor section, i.e. the pipe 64 stands proud of the floor within the first interior space. Thus, the water must collect to a preset depth before it can escape via the drain 64. This preset depth, determined by the amount that the drain pipe 64 stands proud of the floor section, is set as being slightly greater than the spacing between the second internal baffle plate 50 and the floor but less than he spacing between the first and third internal baffle plates 48, 52 and the floor. Thus, the water in the base of the first interior space seals the lower end as the second internal baffle plate 50 as noted above, but allows gas flow past the first and third internal baffle plates 48, 52.

-8In practice, as will be illustrated, a larger or smaller number of nozzles and/or baffle plates can be provided, as necessary in view of the characteristics of the thermal treatment process in question.

Figure 5 shows the second interior space, leading to the exhaust aperture 42. A pair 5 of filters 68, 70 are provided within this space, of a suitable form and type, extending from the roof section to the floor section and thus requiring gas flowing through the second interior space to pass through the filters 68, 70. The filters 68, 70 extend through slots in the roof section and are held in place by T-section handles 72, 74, thus allowing them to be withdrawn for cleaning or replacement. Again, more or fewer filters could be provided as required and as will be described.

Figures 6 to 8 show a first alternative form of scrubber 76. This is essentially the same as the scrubber 36 of figure 2 to 5 but omits the filters 68, 70 in their entirety. It is suited to waste treatment apparatus whose characteristics are such, or which operate in areas where the typical waste is such, that the particulates contained in the exhaust gas stream are substantially entirely removed by the water sprays.

Figures 9 and 10 show a second alternative form of scrubber 78. This is akin to the first alternative 76 but also omits the internal dividing wall 44, and thus the baffle plates and water sprays occupy the entire internal space within the housing 38. As a result, the exhaust aperture 42' is relocated to the rear face of the housing 38, distal from the inlet aperture 40'.

Figures 11 and 12 show a third alternative form of scrubber 80. This is akin to the second alternative 76 but also omits the last (fourth) spray nozzle 60. Figures 13 and 14 show a fourth alternative form of scrubber 82 which also omits the second baffle plate, with the first and third baffle plates and the first, second and third nozzles being relocated accordingly in order to maintain a substantially even spacing and pattern within the interior space. This arrangement no longer creates a circuitous path as such but still requires the gas flow to pass through several water sprays. Finally, figures 16 and 17 show a fifth alternative form of scrubber 84 which omits the last nozzle. The skilled person will be able to select a suitable scrubber from the alternatives set out above (or variants thereon employing substantially the same principles) in the light of the characteristics of the exhaust gases in question.

-9It will of course be understood that many variations may be made to the above described embodiment without departing from the scope of the present invention.

Claims

1. A waste disposal apparatus comprising a heat treatment chamber for processing the waste at an elevated temperature, the chamber having a vent leading via a heat exchanger to a scrubber comprising a disrupted flow path, at least one spray nozzle

5 directed towards the disrupted flow path, and a supply of water to the or each spray nozzle.

2. A waste disposal apparatus according to claim 1 in which the flow path is disrupted by at least one baffle plate.

3. A waste disposal apparatus according to claim 2 in which the spray nozzle is located

10 above and in front of the baffle plate.

4. A waste disposal apparatus according to claim 2 in which the flow path is disrupted by two or three baffle plates.

5. A waste disposal apparatus according to claim 4 in which a spray nozzle is located above and in front of each baffle plate.

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6. A waste disposal apparatus according to any one of claims 2 to 5 in which the scrubber includes a floor section below the flow path, and the lower edge of each baffle is spaced from the floor section along at least a part of that edge.

7. A waste disposal apparatus according to claim 6, further comprising a drain allowing escape of the water from the scrubber from a level which is a preset distance above

20 the internal level of the floor, wherein the lower edges of the baffles are spaced from the floor by distances that are alternately greater than and less than the preset distance, and the baffles whose lower edges are spaced from the floor by less than the preset distance have an upper edge that is spaced from a roof section of the scrubber along at least a part of that upper edge.

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8. A waste disposal apparatus according to claim 7 in which the drain comprises a conduit that extends upwardly through the floor with an open end standing proud of the floor by the preset distance.

-119. A waste disposal apparatus according to any one of the preceding claims in which the flow path is disrupted in that it does not comprise a straight line path.

10. A waste disposal apparatus according to any one of the preceding claims in which the flow path includes at least one filter.

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11. A waste disposal apparatus according to claim 10 in which the filter is located after the or each spray nozzle.

12. A waste disposal apparatus according to claim 11 in which the scrubber comprises a housing divided longitudinally by a dividing wall, the housing having an inlet located on one side of the dividing wall, and an aperture in the dividing wall, wherein the inlet

10 receives gas flow from the vent, the disrupted flow path leads from the inlet to the aperture, and the filter is located on the opposite side of the dividing wall.

Intellectual

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Office

Application No: GB1706489.0