Vertical carbon activation retort

Abstract

A vertical carbon activation retort is disclosed, comprising a central column with a hollow interior. The column features an upper end for receiving feed material and a lower end for discharging activated material. The central column is partitioned into at least two interconnected chambers, facilitating the sequential flow of feed material between chambers during operation. Each chamber is equipped with a syngas offtake, enabling the extraction of syngas from the chamber during the activation process.

Description

[0001] VERTICAL CARBON ACTIVATION RETORT

[0002] BACKGROUND TO THE INVENTION

[0003] This invention relates to a vertical retort, and more particularly but not exclusively to a vertical carbon activation retort.

[0004] Although kilns and retorts are not the same, they are sufficiently similar to be in combination described as retorts in this specification, and reference to one extends to the other.

[0005] Activated carbon is a form of carbon derived from various carbonaceous source materials, including bamboo, coconut husk, willow peat, wood, coir, lignite, coal, and petroleum pitch. Activated carbon is widely used in a variety of applications, including water and air purification, gas separation, and chemical processing. It is also used in a range of industries, such as pharmaceuticals, food and beverage, and cosmetics, as a means of removing impurities and improving product quality. Overall, activated carbon is therefore an effective and versatile material that plays an important role in many industrial processes and environmental applications.

[0006] Activated carbon can be produced by way of physical activation or chemical activation, but this invention is directed to physical activation. During physical activation, the source material is typically first carbonized by way of pyrolysis. During the pyrolysis process, the organic material is heated to a temperature of around 500-800 degrees Celsius in an oxygen-free environment. This causes the material to break down into a complex mixture of gases, liquids, and solids, with the solid portion containing a high proportion of fixed-carbon. The carbonized material is then activated or oxidized by exposing the material to an oxidizing atmosphere (carbon dioxide or superheated steam) at elevated temperatures, usually in the temperature range of 600-1200 °C.

[0007] Once activated, the carbon is typically processed into various forms, such as granules, pellets, or powders, depending on the specific application. Activated carbon can also be further treated to modify its properties, such as by impregnating it with chemicals to enhance its adsorption capacity for specific contaminants.

[0008] Physical activation of a carbonized source material typically happens in a suitable type of furnace or reactor, such as a rotary kiln or a vertical retort. Rotary kilns are mostly used during the activation process, but the use of vertical retorts is also known, for example the reactor shown in US 2,536,782, where the bottom half of the disclosed reactor is used for activation. The reactor disclosed in US2,536,782 is a combined reactor in which both carbonization and activation occur.

[0009] In general terms, a vertical retort is a type of retort that can be used in the activation of charcoal, activated carbon, or other carbon-rich materials. The term "vertical" refers to the orientation of the retort, which is typically positioned in a vertical, upright manner. Unlike horizontal retorts, where the material is loaded horizontally, a vertical retort is loaded in a vertical position, usually from the top. The source or feed material is placed into the top of the retort and gravity-fed downward during the activation process. A vertical retort is constructed as a tall, cylindrical or rectangular, airtight structure with a vertical shaft or chamber inside. The top of the retort is the loading area, and the activated material is collected at the bottom.

[0010] As part of the activation process, the carbonized material is fed into the top of the retort, while a burner or heating element located at the bottom of the retort generates the heat necessary for the activation process. An activation agent, such as steam or carbon dioxide, is introduced into the retort at various points along the shaft or vertical chamber, typically through a series of nozzles or pipes. Careful control of the temperature and flow of the activation agent is critical to ensure that the carbonized material is evenly exposed to the activating agent and that the resulting activated carbon has the desired pore size distribution and surface area. The exact operating parameters will depend on the specific application and the type of charcoal being used.

[0011] It will be clear from the above that the activation process requires significant energy, in particular to heat the material to be activated, and also to provide steam for use in the activation process. Existing systems are endothermic and not particularly energy efficient, which is a major disadvantage and challenge from an environmental and energy efficiency perspective.

[0012] It is accordingly an object of the invention to provide an activation retort that will, at least partially, alleviate the above shortcomings.

[0013] It is also an object of the invention to provide an activation retort which will be a useful alternative to existing activation retorts.

[0014] The inventor believes that the efficiency of existing systems can be significantly improved - to the point where the process uses significantly less energy compared to prior processes, and preferably to the point where the process is exothermic. SUMMARY OF THE INVENTION

[0015] According to the invention there is provided a vertical carbon activation retort including: a central column having a hollow interior, the column having an upper end at which feed material is received, and a lower end where activated material is removed; the central column being divided into at least two chambers, wherein the at least two chambers are in flow communication allowing the feed material to flow from one chamber to the next chamber; and wherein each chamber includes a syngas offtake for in use removing syngas from the chamber.

[0016] There is provided for a steam inlet to be provided in the operatively lower of the two chambers.

[0017] In one embodiment, there is provided for the central column to be divided into three chambers, with each chamber including a syngas offtake for in use removing syngas from the chamber, and wherein steam inlets are provided in the middle chamber and the operatively lower chamber.

[0018] There is provided for the central column to be divided into chambers by way of dividing members, more particularly dividing discs.

[0019] The discs are angularly offset or slanted, with each disc in use having an upper edge on one side of the column, and a lower edge on a diametrically opposed side of the column.

[0020] There is provided for the upper edge of a disc to form a gas collection pocket in combination with a sidewall of the column.

[0021] There is provided for the syngas offtake to be located at or near the gas collection pocket. The syngas offtakes are in flow communication with flare tubes for use in igniting syngas removed from the chambers, with the flare tubes being located in a void below the central column.

[0022] A further feature provides for feed material flow openings to be provided in the lower edges of the dividing members in order to allow feed material to flow downwardly from one chamber to a next chamber.

[0023] A still further feature provided for the two dividing discs to be rotationally offset relative one another, preferably 120 degrees.

[0024] In accordance with a further aspect of the invention a hollow central conduit extends through the column along a longitudinal axis of the column.

[0025] There is provided for configuration to be such that gas can in use move upwards or downwards in the hollow central conduit.

[0026] In one embodiment, there is provided for the central conduit to have an upper open end which is in flow communication with a source of heated gas, for example gas having been heated by the flare tubes.

[0027] More particularly, the retort includes a flow path from the void below the column, through an annular space between an outer surface of the central column and an inner surface of insulation surrounding the column, into the upper open end of the central conduit.

[0028] A bottom open end of the central conduit is in flow communication with a steam generator. A fluid mover, for example a fan, is provided to induce flow from the bottom end of the fluid conduit to the steam generator. In another embodiment, there is provided for the lower open end of the central conduit to be in flow communication with a source of heated gas, for example a waste heat exchanger or an electric steam generator.

[0029] In accordance with a further aspect of the invention the retort includes a feed material inlet arrangement which comprises:

[0030] - a first valve;

[0031] - a second valve;

[0032] - a holding zone located between the first valve and the second valve; and

[0033] - a feed conduit extending from the second valve into the central column.

[0034] According to a further aspect of the invention there is provided a method of activating a carbonized feed material using a vertical carbon activation retort, the vertical carbon activation retort having a central column with a hollow interior, the column having an upper end at which the feed material is received, and a lower end where activated material is removed, the central column being divided into at least two chambers, with each chamber including a syngas offtake for in use removing syngas from the chamber, the method including the steps of:

[0035] - introducing the feed material into the upper end of the vertical carbon activation retort;

[0036] - introducing steam into at least one of the chambers;

[0037] - removing activated material from a lower end of the vertical carbon activation retort; and

[0038] - removing syngas from at least one of the chambers.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention is described by way of a nonlimiting example, and with reference to the accompanying drawings in which:

[0040] Figure 1 is a side view of the vertical retort in accordance with the invention, including the frame and insulation;

[0041] Figure 2 is a cross-sectional side view of the retort of Figure 1 , with only some components indicated by reference numerals;

[0042] Figure 3 is a cross-sectional end view of the retort of Figure 1 ;

[0043] Figure 4 is a cross-sectional perspective view of the retort of Figure 3;

[0044] Figure 5 shows a cross-sectional side view of the retort of Figure 1 and 3 without the frame and insulation;

[0045] Figure 6 shows an upper section of the retort of Figure 5;

[0046] Figure 7 shows a central section of the retort of Figure 5; and

[0047] Figure 8 is a cross-sectional end view of the retort of Figure 3 without the frame and insulation.

[0048] DETAILED DESCRIPTION OF INVENTION

[0049] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings and are thus intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

[0050] Referring to the drawings, in which like numerals indicate like features, a non-limiting and simplified example of a vertical carbon activation retort in accordance with the invention is generally indicated by reference numeral 10.

[0051] The vertical retort 10 includes a central section 100 which is surrounded by insulation (15 and 16), all carried by a frame 11. The frame structure 11 includes an upper end 11.1 and a lower 11.2 end terminating in feet 12. The retort is generally divided into an upper zone 13, which houses the central section 100, and a lower zone 14 which houses the product outlet 29, the lower end 32 of the central conduit 30, the flare tubes 43, and an auxiliary oil heater and fan 17, all of which will be described in more detail below. Insulation 15 in the upper zone 13 surrounds the central section 100, with an annular space 19.1 formed between an inner surface of the insulation 15 and an outer surface of a cylindrical column 20 of the central section 100. The insulation 16 in the lower zone forms a void 19.2 below the cylindrical column 20 of the central section 100. A steam generator (not shown) is provided below the retort 10 and may be in the form of a flash boiler or any other suitable steam generator that can generate steam utilizing waste heat. The detail design of the steam generator is not of a limiting nature.

[0052] High grade ceramic fiber modules are used for insulation (15 and 16) to keep energy and heat within the vertical reactor. Energy loss is kept below 10%.

[0053] A light oil burner and fan 17 is provided for use during the startup of the retort and is located in the lower zone 14 of the retort. The inlet void 19.2 defines a plenum in which the air is blown into. The light oil burner and fan is offset relative to a longitudinal axis of the central section, thus causing a cyclonic flow action in the void. This flow pattern is supported by the directional orientation of flare tubes 43 at the ends of the syngas offtake pipes (40, 41 and 42) (described in more detail below), which are also directed to be in line with the swirling flow pattern. By having a flame directed in a circular direction, the movement of oxygen and reaction with off gas as the fuel will create a horizon flow path. Due to natural convection the heated gases of combustion will follow a circular motion. This in turn decreases the vertical velocity of heat upwards and allows for a greater contact duration with the metal column and in turn allows for an increased thermal transfer potential.

[0054] The primary component of what is denoted as the central section 100, is a cylindrical central column 20. This column is in the form of an elongate, circular pipe having a hollow interior. An upper end 21 of the column is sealed off by a flange 21 , as is the lower end 22, thus defining an enclosed volume. A feed opening (not shown) as well as a central conduit opening 28 are provided in the upper end 21 of the column. A discharge opening (not shown) and a further central conduit opening 27 are provided in the lower end 22 of the column. The discharge opening in the lower end 22 is in flow communication with a product outlet 29. The lower end 22 is in the form of a slanted disc, with the product outlet 29 located at the operatively lower end of the disc, thus resulting in a natural outflow of activated product from the column 20.

[0055] Two dividers (23 and 24) are located inside the column 20 and divide the interior volume of the column 20 into an upper chamber 20.1 , a middle chamber 20.2 and a lower chamber 20.3. The provision of more than one (and preferably three) chambers is an important aspect of the invention. The invention will also work with two chambers, but at least three is preferred. The upper chamber 20.1 acts as a dehydration and devolatilization chamber and dries the feed material. This is particularly important in cases where the carbonized material is of low quality and includes so-called “brown spots”. However, there will almost always be at least some volatiles carried over from carbonization. It is not ideal to combine dehydration and activation, which is why the upper (or third) chamber is functionally desirable. There is accordingly no steam injection in the upper chamber 20.1 , but it still has a syngas offtake 40 (discussed below).

[0056] Activation takes place in the middle chamber 20.2 and the lower chamber 20.3, both of which therefore includes steam inlets (51 and 52) and syngas offtakes (41 and 42).

[0057] The dividers are in the form of discs that are angularly offset or slanted relative to a horizontal plane taken through the column 20 when viewed from the side. The dividers are offset at an angle of about 25 degrees. The two dividers are, however, not parallel to one another, with the highest point of the two dividers being rotated between 90 and 180 degrees, preferably 120 degrees, relative to one another. This rotational offset results in a non- linear swirling movement of feed material (when viewed from the top) as it moves down the column, and therefore in better distribution. The configuration also means that feed material openings (25 and 26) are offset when viewed from the side, thus also resulting in a non-linear serpentine downward movement (when viewed from the side).

[0058] It will be appreciated that since the dividers are angularly offset or slanted when viewed from the side, the middle chamber 20.2 and the lower chamber 20.3 both include an upper pocket (20.4 and 20.5 - best seen in Figure 8) formed between the dividers and the sidewall of the central column 20.

[0059] A peripheral outlet opening 25 is provided in the upper divider 23 at the lowest end of the slanted 23 divider, which is the end diametrically opposite the upper pocket 20.4 of the middle chamber 20.2. Likewise, a peripheral outlet opening 26 is provided in the lower divider 24 at the lowest end of the slanted divider 24, which is the end diametrically opposed to the upper pocket 20.5 of the lower chamber 20.3. This configuration ensures that the upper pockets (20.4 and 20.5) does not fill up with feed material when in use, as the entry point for feed material into each chamber - i.e. the peripheral openings (25 and 26) - are lower than the pockets (20.4 and 20.5). In use, syngas will therefore collect in the upper pockets, as this will be the path of lowest flow resistance.

[0060] Syngas is released during the activation of carbon in the production of activated carbon. Syngas, short for synthesis gas, is a mixture of carbon monoxide (CO) and hydrogen (H2) that is produced by the partial oxidation of carbonaceous materials such as coal, wood, or charcoal. During the activation process, the carbonaceous material is heated to high temperatures in the presence of an activating agent such as steam or carbon dioxide. This causes the material to undergo a series of chemical reactions that release volatile organic compounds (VOCs) and other gases, including syngas. The syngas is typically generated by the partial oxidation of the carbon in the feedstock and can be used as a fuel source or for other industrial processes. The exact amount and composition of syngas generated during the activation of carbon will depend on factors such as the type of feedstock, the activation conditions, and the presence of catalysts or other additives. In existing activation processes, syngas is generally burnt inside the retort as a fuel source inside the column. However, it is very difficult to control temperature accurately if the syngas is burnt inside the column, and it is therefore also difficult to achieve an optimal temperature profile. For this reason, the present invention functions conceptually differently in that the syngas is removed from the retort, piped to the bottom of the retort, ignited and then reintroduced, thus resulting in better heating properties. Syngas can also be used to other purposed, e.g. generation of electricity.

[0061] A central conduit 30 extends through the column 20 along a longitudinal axis of the column 20. The central conduit has an open upper end 31 terminating in the opening 28 in the upper end of the column, and a lower end 32 terminating in the opening 27 in the lower end of the column, thus defining an unrestricted flow passage through the middle of the column. The upper end 31 is in flow communication with the annulus 19.1 and thus the void 19.2, and heated gas emanating from the void can therefore rise through the annulus 19.1 and enter the upper end 31 of the central conduit. The lower end 32 of the central conduit is in flow communications with a steam generator, with flow from the central conduit to the steam generator being induced by a centrifugal fan (not shown). In use, there will therefore be a flow passage from the void 19.2 into the annulus 19.2 and into the upper end of the central conduit, and then from the central conduit to the steam generator.

[0062] Although not shown in the drawings, an inspection port is provided at the top of the central conduit 30. A number of offtake pipes are provided to remove syngas from the inside of the column 20 and to convey the syngas to the void 19.2. An upper offtake pipe 40 extends from an upper zone of the upper chamber 20.1 downwardly to the void 19.2. A middle offtake pipe 41 is in flow communication with the upper pocket 20.4 of the middle chamber 20.2 and extends downwardly to the void 19.2. A lower offtake pipe 42 is in flow communication with the upper pocket 20.5 of the lower chamber 20.2 and extends downwardly to the void 19.2. All three offtake pipes terminate in flare tubes 43, where the syngas is ignited in order to heat surrounding air. This heated air subsequently travels upwards through the annulus 19.1 and the downwards though the central conduit 30.

[0063] Flare tube inspection ports 44 are provided to inspect the flare tubes, and also to provide a sensor point for a differential pressure sensor. More particularly, there is provided for the pressure differential to be measured between the syngas pipes and steam pipes for each of the chambers. The measurements will have to be empirically quantified, but the provision of the differential pressure measurement points will make it possible to us pressure differential datapoints to determine the efficiency of activation, and to determine if too little or too much steam is supplied.

[0064] As mentioned above, a steam generator (not shown) is provided, and utilises the waste heat coming from the central conduit 30 to generate steam. The steam so generated is in turn fed into the central column. More particularly, a lower steam conduit feeds steam into the lower chamber 20.3, and a middle steam conduit feeds steam into the middle chamber 20.2. It should be noted that the steam is injected towards the bottom of each chamber, and in a position diametrically opposed to the openings (25 and 26) in the corresponding dividers (23 and 24) in order to ensure symmetrical flow distribution and reduce possible dead spots. If the steam was introduced on the same side as the openings, a dead zone could potentially be formed on the other side of the column. The feed material (some form of carbonized material) is fed into the central column 20 through an opening in the top end 21 . A dual valve feed system 60 is utilized in order to ensure that a constant airlock is formed. The system comprises a first valve 61 , a second valve 62 and a holding cavity in the form of a predetermined length of pipe 63 provided between the two valves. A central feed pipe 64 extends from the outlet of the second valve 62 into the top end of the column 20. The level of feed material in this pipe can be determined using, for example, thermal differential thermocouples or a laser level detector (not shown). Other level detection means could also be used. When level drops below a certain predetermined level, the feed arrangement will facilitate the introduction of more feed material into the vessel. As mentioned above, the two knife valves are never open at the same time (time sequenced) thus ensuring that pressure in the column is at all times contained.

[0065] The central column 20 is secured relative to the frame 11 by way of hangers 70 which allows the column to expand freely as thermal expansion takes place during an increase in heat. In typical operation there is provided for the column to expand by about 125mm, but the arrangement will be able to accommodate even higher degrees of expansion.

[0066] A plurality of thermocouples 80 are provided in the column and are used to measure the temperature in the column in order to determine the temperature profile and then to adjust the airflow is the temperature profile is not correct. The speed of the centrifugal fan can, for example, be controlled in order to control the temperature profile.

[0067] In one embodiment, the retort 10 also includes some sort of resonance source (not shown) at the top of the central column 20. This could for example be a sonic or mechanical source. The purposes of this is to induce resonance, which will assist with fluidization of the material in the column, while at the same time also improving material flow by acting as a ‘shaker’. Fluidization is a process in which a granular material, such as sand, catalyst particles, or carbonaceous material, is suspended and mixed in a stream of fluid, typically a gas like air or steam. The fluidization process occurs when the upward flow of gas through the bed of particles reaches a velocity sufficient to overcome the gravitational forces acting on the particles. At this point, the bed of particles behaves like a fluid, with the particles moving and mixing freely in the gas stream. Improved fluidization will result in improved homogenization, which will in turn result in better steam distribution and hence better activation.

[0068] The inventor also foresees the potential use of steam pulsation, which could be used on its own or in addition to a resonation sources.

[0069] In use, feed material is introduced into the central column 20 through the feed arrangement 60. The two PLC controlled gate valves (61 and 62) open and close sequentially (typically open for 3 seconds at a time) with the two valves never in an open state at the same time. Feed material falls into the holding cavity 63 above the second valve 62, which cavity is filled to just below the first valve 61. The material flow rate is controlled and assisted by way of an external vibration feeder (not shown). After three seconds of settling, the second (bottom) valve 62 opens for three seconds and clears out the material in the holding cavity 63, from where it is fed into the central column. Importantly, at no point will the airlock be broken.

[0070] The level control of the feed material flowing into the central column is measured and managed by measuring differential temperature using a thermocouple 80. The system utilizes multiple thermocouple probes extending down the entire length of the central column, and as ambient feed material are fed into the column, the thermocouple senses a drop in temperature at the level of the feed material. The temperature level then informs the PLC whether the level of material is within a bandwidth directly proportional to the level required. The PLC initiates a loading cycle should the level move outside the required level bandwidth. Carbonized particles of 2 - 10 mm in size are introduced into the upper chamber 20.1 of the central column 20. These particles will typically have an initial volatile matter content of between 6 - 15%. Heat within the column provides the kinetic energy required to liberate the bound hydrocarbons into a gas mixture. The liberated volatile gas then flows out of the upper offtake pipe 40. The gas is fed to the combustion zone of the reactor (in the void 19.2), ignited through the flare tubes 43 and provide heat energy to sustain the reaction. The upper chamber does not have any injection of steam and works as a de-volatizing step while also preheating the carbonized particles before being gravity fed to the middle chamber 20.2.

[0071] The de-volatized carbonized material now moves down into the middle chamber 20.2 and is oxidized with steam injection through one or more steam inlet pipes 52 extending upwardly from the bottom of the reactor. This process is repeated at the lower chamber 20.3. At a temperature of 750°C and above, an endothermic reaction can take place which allows the steam (H2O) to oxidise the charcoal (C) and liberating carbon within the charcoal pore structure. This reaction forms two gases, Hydrogen (H2) and Carbon Monoxide (CO). These two combustible gases flow through their own syngas offtake pipes (41 and 42) down to the combustion zone. The gases are ignited and produce heat to sustain the endothermic reaction.

[0072] The introduction of steam from the steam generator (not shown) into the middle chamber 20.2 and lower chamber 20.3 is adjustable relative to the feed rate of the carbonized material. Generally, 2.2 kg of water is used per 1 kg output activated material produced.

[0073] The provision of the three individual offtake pipes (40, 41 and 42) minimizes contamination of carbonized material by gasses given off in lower chambers as it passes down the chambers. This syngas diversion, and hence reduced contamination of material in upper chambers, increases the total surfacer area of the activated carbon being produced. The diversion of gasses is also efficient in that gases in each chamber take the path of least resistance and flow freely in their required paths, which is in particular facilitated by the design of the dividers and the formation of the pockets (20.4 and 20.5).

[0074] The gasses recovered via the offtake pipes (40, 41 and 42) are ignited and passed through the central conduit 30 before being used in the steam generator (not shown). More particularly, a six-inch center pipe runs from the top of the column 20 right down through the column and through the bottom insulation. The pipe is open at the top of the column, which means that hot gases can be sucked downwards. The suction is created by a centrifugal fan supplying waste heat to a waste heat steam generator. The hot air flow increases thermal distribution within the three chambers from the center outwards, and the additional heat coming from the outside of the column (as the gas travels up the annulus 19.1) creates thermodynamic equilibrium potential. In summary the net energy of the reactor generates more energy than what is required to sustain both activation and steam generation.

[0075] The final activated charcoal produced flows out through a release channel at the bottom end of the lower chamber 20.3. The release of this material is controlled by a screw auger (not shown).

[0076] It will be appreciated that the above is only one embodiment of the invention and that there may be many variations without departing from the spirit and / or the scope of the invention. It is easily understood from the present application that the particular features of the present invention, as generally described and illustrated in the figures, can be arranged and designed according to a wide variety of different configurations. In this way, the description of the present invention and the related figures are not provided to limit the scope of the invention but simply represent selected embodiments. For example, in another embodiment of the invention, there is provided for the gas travelling through the central conduit to travel upwards instead of downwards. In such embodiment, there is provided for the lower open end of the central conduit to be in flow communication with a source of heated gas, for example a waste heat exchanger or an electric steam generator.

[0077] The skilled person will understand that the technical characteristics of a given embodiment can in fact be combined with characteristics of another embodiment, unless otherwise expressed or it is evident that these characteristics are incompatible. Also, the technical characteristics described in a given embodiment can be isolated from the other characteristics of this embodiment unless otherwise expressed.

Claims

CLAIMS:1 . A vertical carbon activation retort including: a central column having a hollow interior, the column having an upper end at which feed material is received, and a lower end where activated material is removed; the central column being divided into at least two chambers; wherein the at least two chambers are in flow communication, allowing the feed material in use to flow from one chamber to the next chamber; and wherein each chamber includes a syngas offtake for in use removing syngas from the chamber.

2. The vertical carbon activation retort of claim 1 including a steam inlet in the operatively lower of the two chambers.

3. The vertical carbon activation retort of claim 1 or 2 wherein the central column is divided into three chambers, with each chamber including a syngas offtake for in use removing syngas from the chamber, and wherein steam inlets are provided in the middle chamber and the operatively lower chamber.

4. The vertical carbon activation retort of any one of the preceding claims wherein the central column is divided into chambers by way of dividing members in the form of discs.

5. The vertical carbon activation retort of claim 4 wherein the discs are angularly offset or slanted, with each disc in use having an upper edge on one side of the column, and a lower edge on a diametrically opposed side of the column.

6. The vertical carbon activation retort of claim 5 wherein the upper edge of a disc forms a gas collection pocket in combination with a sidewall of the column.

7. The vertical carbon activation retort of claim 6 wherein the syngas offtake is located at or near the gas collection pocket.

8. The vertical carbon activation retort of any one of the preceding claims wherein the syngas offtakes are in flow communication with flare tubes for use in igniting syngas removed from the chambers, with the flare tubes being located in a void below the central column.

9. The vertical carbon activation retort of any one of claims 4 to 7 wherein feed material flow openings are provided in the lower edges of the dividing members in order to allow feed material to flow downwardly from one chamber to a next chamber.

10. The vertical carbon activation retort of any one of claims 4 to 7 or 9 wherein the two dividing discs are rotationally offset relative to one another.

11. The vertical carbon activation retort of claim 10 wherein the two dividing discs are rotationally offset by 120 degrees.

12. The vertical carbon activation retort of any one of the preceding claims wherein a hollow central conduit extends through the column along a longitudinal axis of the column.

13. The vertical carbon activation retort of claim 12 wherein the configuration is such that gas can in use move upwards or downwards in the hollow central conduit.

14. The vertical carbon activation retort of claim 12 wherein the central conduit has an upper open end which is in flow communication with heated gas having been heated by flare tubes.

15. The vertical carbon activation retort of claim 12, 13 or 14 wherein the retort includes a flow path from the void below the column,through an annular space between an outer surface of the central column and an inner surface of insulation surrounding the column, and into the upper open end of the central conduit.

16. The vertical carbon activation retort of any one of claims 12 to 15 wherein a bottom open end of the central conduit is in flow communication with a steam generator.

17. A feed material inlet arrangement comprising: a first valve; a second valve; a holding zone located between the first valve and the second valve; and a feed conduit extending from the second valve into the central column.

18. A method of activating a carbonized feed material using a vertical carbon activation retort, the vertical carbon activation retort having a central column with a hollow interior, the column having an upper end at which the feed material is received, and a lower end where activated material is removed, the central column being divided into at least two chambers, with each chamber including a syngas offtake for in use removing syngas from the chamber, the method including the steps of:- introducing the feed material into the upper end of the vertical carbon activation retort;- introducing steam into at least one of the chambers;- removing activated material from a lower end of the vertical carbon activation retort; and- removing syngas from at least one of the chambers.

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