Field of the Invention

This invention relates to an apparatus for a continuous flow chemical reaction, a method of process control to improve yield in a chemical reaction and the manufacture of materials from biological raw materials.

Background of the Invention

Electromagnetic radiation energy transfer has proven to be a highly effective heat source for promoting many chemical reactions. This uniform nature of this energy transfer can accelerate the reaction rate, or selective heating, thereby encouraging greater reproducibility of the target chemical reaction.

Chemical reactions promoted by electromagnetic radiation have been a fundamental principal of many analytical or synthetic laboratory scale apparatus for many decades. These types of apparatus have evolved into two categories, those having: a single-mode; or a multi-mode reaction cavity or chamber.

A single-mode cavity is designed to create a standing wave pattern of the incident electromagnetic radiation. This type of cavity design allows for precise energy transfer to occur at the node regions of the standing wave, while no energy transfer occurs in the anti-node regions.

A multi-mode design actively discourages long term standing waves but arranges for the radiation waves to be randomly and chaotically reflected around the chamber. On average the same amount of energy may be transferred to the target substrate but in the case of the multi-mode design sub-samples of the feed may receive considerably more or less energy than that average figure. The energy transfer range is much tighter for the single- mode system. The possible greater variability of energy transfer of the multi- mode design somewhat undercuts non-varying (even) and controlled energy delivery benefits claimed for electromagnetic radiation energy transfer.

Hygienic and environmentally acceptable disposal of human and animal waste body fluids is a problem world-wide. While such body wastes are of biological origin, and therefore do not pose a carbon dioxide emission problem, their uncontrolled putrefaction can be the source of community health problems. Frequently, to reduce the human health impact, waste water or sewage treatment processes are put in place at considerable cost to the community. However the discharge of concentrated, and often very mobile, nutrients resulting from such processes can have a very damaging impact on the local aquatic environment.

The high mobility of the nutrients can extend the reach of the impact over a wide area. For example, the regular closing of coastal beaches due to very high concentrations of poisonous algae in the marine environment can often be traced to the uncontrolled discharge from a municipal sewage treatment system tens if not hundreds of kilometres away.

Prior Art

Since 1997 the benefits of microwave electromagnetic radiation heating has been applied to a number of industrial or semi-industrial processes. Mostly these processes have been in the fields of batch pharmaceutical or biotechnology product synthesis.

Since 2004 a number of manufacturers of microwave heated systems have offered apparatus with flow-through reaction chambers offering greater productivity to industrial processes. However by 2008 the wide spread use of microwave heating systems in general industrial processes has been limited by: difficulties increasing the size or throughput of the apparatus to meet industrial scale operation; and contaminants or by-products which may deposit in the reaction chamber and can only be removed by shutting the system down. This also results in reduced productivity for the system.

Many industries with a perceived or actual high carbon foot-print are trying to mitigate their impact on the global environment by transferring the process that results in their production of carbon dioxide to use materials of biological origin. One example is the international civil airline industry which has a programme to trial and convert to a biologically sourced equivalent to the petroleum sourced Jet A1 used to fuel their aircraft.

Pyrolysis and similar processes have been used to produce high value lower molecular weight products from high molecular weight low value feedstock for many decades. Examples of such products include Town Gas from coal, metallurgical coke from coal, the cracking of crude petroleum to produce liquid fuels such as gasoline and diesel, and activated carbon from coconut fibre.

The transfer of thermal energy to the pyrolysis reaction has traditionally involved a conduction mechanism whereby burners apply heat to the outer walls of the process container or retort. The container walls are usually made of a heat conductive material such as steel which thereby encourages the conduction of the heat to the material inside the container. There are many examples where the thermal control of such processes has been improved by the adoption of a secondary heat transfer mechanism.

This secondary mechanism may or may not involve heat transfer by convection. One such example is 'fluidized bed' technology where a fluidizable heat transfer medium is heated separately from the substrate that is the target of the process. Heat is transferred by rapidly dispersing the heat transfer agent into the substrate in a manner that encourages intimate contact between the two materials.

Biological and mechanical systems have been developed that are designed to process human and animal body waste streams. For human wastes the systems can be graded one to five, with one being basic screen separation of the solid material through to stage five which discharges almost potable water into the local environment. However even a stage five system produces a considerable amount of semi-solid sewage sludge which must be handled separately. In many cases the production of organic fertiliser from sewage sludge has not been successful and this material has been diverted to disposal by landfill.

The capital investment in a stage five sewage treatment facility is considerable. This poses a community wealth and/or size barrier to the deployment of such systems. There are many communities that cannot afford, or are too small to support a sophisticated sewage treatment system and continue to discharge waste water which is seriously affecting their local environment.

Similar biological and/ or mechanical systems have been developed to handle large volumes of animal waste. The 'three-pond' treatment system for the effluent from New Zealand dairy shed is one example of a system designed to treat animal waste. However, there is a significant body of documentary evidence that these systems are inadequate and are failing to protect underground aquifers and surrounding water systems from contamination by nutrient run-off from intense animal raising operations.

The Dairying and Clean Streams Accord, signed in May 2003, between Fonterra Co-operative Group, Regional Councils, Ministry for the Environment and Ministry of Agriculture and Forestry is an example of an industry response to continued contamination of the country's water ways by animal-derived nutrient overload.

Summary of the Invention

According to the present invention there is provided an apparatus for continuous flow chemical reaction comprising: a reaction chamber defined within a reaction tube which is substantially transparent to electromagnetic radiation of the frequency being used; a cavity surrounding the reaction chamber and enclosing a reaction tube, through which, in use, reaction material is guided, at least a portion of the reaction tube is partially surrounded by the cavity or sleeve shield tubes fitted to either side of the cavity; and an electromagnetic radiation source, connected via a wave guide, for introducing electromagnetic radiation into the cavity; the dimensions of the cavity and length and diameter of the sleeve shield tubes are tuned to the frequency of the electromagnetic radiation being introduced, such that the electromagnetic radiation is focused into a very small region in the centre of the reaction tube.

There are several aspects to the invention including an apparatus for a continuous flow chemical reaction utilising electromagnetic radiation; a method of process control for improvement of yield of a chemical reaction; and the conversion of biological organic sources including human and animal waste products into liquid products that can be used as an alternative to petroleum waxes and solid products that can be used as a soil conditioning medium.

The invention is a design of a chemical reaction assembly that allows for the efficient and carefully controlled transfer of electromagnetic energy to the reaction mixture or reagents. The assembly includes the design of the cavity, the design of the sleeve shield tubes attached to either side of the cavity and the fitting of the reaction chamber into the through centre of the cavity via the sleeve shields.

Preferably the apparatus comprises an attachment for the introduction of a cleaner into a first end of the reaction tube. This first end of the tube may also be used as the in-feed for reagents/reactants.

Preferably, the apparatus includes an attachment for the removal of a cleaner from a second end of the, or each, reaction tube.

The cleaner is preferably a plug made from a material which does not degrade in the presence of reactants and products of the chemical reaction(s) within the reaction chamber. The plug is preferably of a diameter such that it lightly contacts the inner surface of the tube thereby cleaning the tube as it is moved along the tube length by the flow of the reagents within the tube. The plug may also comprise a textured surface to enhance removal of any material which adheres to the tube wall.

In a preferred embodiment more than one reaction chamber is used. This provides convenient up-scaling of the process. It is understood that more than one reaction chamber may be housed in a single unit to make transport and use of the multi-chambered apparatus easier. Some components of the apparatus are preferably shared between different reaction chambers.

According to another aspect of the invention there is provided a method of heat treating reagents using electromagnetic radiation comprising the steps of:

providing a reaction tube having two ends;

introducing electromagnetic radiation into at least a portion of the reaction tube; and

introducing a flow of reagents into one end of the reaction tube whereby, in use, as the reagents flow through the reaction tube, the reagents are affected by the electromagnetic radiation causing a chemical reaction, the products of the chemical reaction exiting from the other end of the reaction tube.

According to a third aspect of the invention there is provided a process control method suitable for a heat treatment process comprising the steps of:

providing a substrate;

introducing one or more agents/additives for example: coupling agents; a catalyst; catalyst control agents; side reaction suppressants; materials for aiding recovery and/or isolation of a desired side product; and materials for aiding isolation or nullification of an undesired side product;

utilising accessory processes on the substrate plus additives to produce an intermediate product;

processing the intermediate product in a main process to produce a product; and

metering the flow of substrate and products through at least one of the processes.

Ancillary processes include those that increase or concentrate desirable material in the substrate; that improve or optimize the physical contact between the substrate and any/all introduced agents; that 'fluidize' the substrate; that; isolate products, condition products for further processes; isolate coupling or other agents that may have been introduced as part of a accessory process or processes, isolate agent(s) that may be used in an accessory process or processes, and/or isolate agent(s) that may be used to recycle process energy to any of the accessory processes.

This invention includes the use of an electromagnetic radiation (ER) energy transfer mechanism, along with any of the accessory processes which optimize or improve the efficiency of the ER energy transfer mechanism, to facilitate any or all of the accessory processes to the main process, or to a set of main processes being operated in series or in parallel. According to a fourth aspect of the invention there is provided a method of processing biological raw materials comprising the steps of:

heat treating biological raw material in a controlled atmosphere;

producing a gaseous product;

producing a liquid product; and

producing a solid product.

Preferably further treatment is provided: in the cases of gaseous product this provides fuel that can be used in any of the heat treatment processes described herein; in the case of liquid product it is densified the liquid into a pitch like material (bio-pitch); in the case of the solid it produces a similar in character to petroleum or coal derived coke (bio-coke).

The bio-pitch is preferably further heat treated to de-volitilise, calcine and graphitise the material producing a bio-electrode i.e. a material which is comparable to and can be used instead of conventional carbon electrodes.

The solid product may be suitable for use as a soil conditioning agent.

In a preferred embodiment, the biological raw materials include materials which have been untreated or partially treated by conventional sewage treatments.

The bio-products include the gaseous fuel products, bio-oil, bio-pitch, and bio- coke, and mean that less sewage waste needs to be disposed in land fill sites.

According to a fifth aspect of the invention the feed mixture is presented to the reaction chamber feed mechanism as an extruded rod.

A preferred embodiment is for the target feedstock and any additives to be presented to the chemical reactor as extruded rods. This invention includes the preparation and extrusion of feed rod. This invention also includes equipment for storing extruded feed rods as well as equipment that can offer the rod to the chemical reactor assembly as required so rendering the chemical reaction as a continuous flow process.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which.-

Brief Description of the Drawings

Figure 1 is a plan view of an apparatus according to the invention;

Figure 2 is a perspective of an apparatus according to the invention;

Figure 3 is an exploded view of the apparatus shown in Figure 1 ;

Figure 4 is a perspective view of an apparatus showing the water cooling system;

Figure 5 is a perspective view of an apparatus showing feedstock; Figure 6 is a graph of thermopile calibration;

Figure 7 is a graph showing power absorbed by water flowing through the apparatus of the invention;

Figure 8 is a flow diagram of steps used in the heat treatment of biological materials; and

Figure 9 is a flow diagram of a process control method. Detailed Description of the illustrated embodiment

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Before a detailed reference to the Figures and preferred embodiments is made, there is a general discussion which is felt to assist the reader.

Microwave radiation, that is electromagnetic radiation with frequencies between 300 MHz and 300 GHz, and other radio-frequency electromagnetic radiation offer an efficient and controllable method for transferring energy to a target substrate. The energy transfer process primarily depends on the interaction between the electromagnetic radiation and polar or polarisable entities within the target mixture. However, secondary energy transfer mechanisms may include interaction with conductive species or the result of interfacial polarisation. A target substrate therefore has a relatively large dielectric loss constant with respect to the frequency of the electromagnetic radiation at the temperature the radiation event is taking place.

Energy transfer by electromagnetic radiation may be directly interacting with catalytic material having a significant dielectric loss constant in a reaction mixture can result further promotion of the reactions enhanced by the catalyst resulting in different reaction products, or a difference in the composition of the reaction products, than that delivered by the same reaction mixture heated by traditional means. This effect on the reaction mechanism offers the opportunity for electromagnetic radiation irradiated processes to be far more efficient than, and/ or deliver higher value products than production systems heated by conductive or convection energy transfer systems.

Organic chemistry covers chemical compounds which have a carbon structural backbone. Organic-chemical compounds commonly also include hydrogen, hetero-atoms such as oxygen and sulphur and less frequently halides such as chlorine, iodine and bromine. Organic chemicals include all compounds with a biological origin as well as materials produced from petroleum or petrochemicals.

RECTIFIED SHEET (RULE 91) ISA/EP In general, mixtures of lower molecular weight organic-chemicals are more useful and therefore more valuable than mixtures of their high molecular weight equivalents. Several industrial processes, including but not limited to petroleum cracking, vis-breaking, thermolysis, pyrolysis and gasification, result in high value lower molecular weight organic-compound mixtures through the heat treatment of high molecular weight organic-compound feedstock.

Most organic-compounds have a large amount of potential chemical energy invested in the bonds of the carbon backbone. This energy can be made available through the process of combustion. Therefore most commonly used fuels are based on organic compound mixtures. Fuels, such as diesel or petrol, composed of lower molecular weight mixtures are more easily handled, have a wider range of applications and are more valuable than high molecular weight mixtures such as bunker fuel or coal.

When treated with heat, some of the carbon to carbon chemical bonds in the backbone of high molecular weight organic compounds may rupture resulting in material with a lower average molecular weight. All of the industrial processes mentioned above rely on this phenomenon. The actual products that result from any particular application of one of these processes depends not only on the feedstock but the precision, thoroughness, evenness and rate at which the heat is applied to that process feedstock.

Thus, the chemical reaction is dependent on the conditions of the reaction (temperature and additives) as well as the apparatus used to facilitate the reaction. The skilled person will appreciate that different aspects of the invention herein described can be used together i.e. the feedstock, processing conditions and apparatus or one or more of these aspects can be utilised with state of the art aspects.

RECTIFIED SHEET (RULE 91) ISA/EP Referring now to Figures 1 , 2, 3 and 4, which all show different, aspects of an apparatus 100 according to the invention. The apparatus 100 comprises a reaction tube 1 10, an electromagnetic radiation supply 130, in this example microwave energy is used , and a microwave cavity 140 is used to focus the microwaves from the microwave supply 130 into the reaction tube 1 10. Sleeve shield tubes 145 are fitted either side of the microwave cavity 140 which guide the reaction tube 1 0 through the centre of the microwave cavity 140, while being tuned to reduce the leakage of microwave radiation through the holes in the side of the microwave cavity 140. Control electronics for controlling the microwave supply are provided and controlled by a microprocessor control unit 150. The microwave cavity 140 is protected against damage from high temperatures using a water cooling system 160.

The reaction tube 110 is made from alumina or alternative material that is transparent to the microwave radiation being used and is mechanically tough under high temperature conditions. Other suitable materials will be apparent to the skilled person. Cajon fittings 1 12, with silicon O-rings (not shown) are attached at each end of the reaction tube 10 to seal the tube from the atmosphere. These fittings 1 12 can be undone to enable the whole assembly to slide out of the way of the feed axis to allow easy replacement/cleaning of the alumina tube.

The Cajon fittings 12 are removably attached to a double gland system {not shown). The cavity between the two glands can be flooded with combustion suppressant such as nitrogen gas providing a non-combustible protective gas blanket and an additional barrier against atmospheric oxygen leaking into the reaction tube. The double gland system is mounted on fixed flanges 114 using O-rings (not shown) again to provide good sealing so air is excluded from the reaction tube and any gases produced during a reaction process are retained in the reaction tube.

RECTIFIED SHEET (RULE 91) ISA/EP In a preferred embodiment the reaction chamber comprises a straight tube 1 10. The tube can be mounted at any angle, including horizontal or vertical. If the reaction chamber is mounted other than horizontal it can be arranged for the reagent mixture to flow through the tube in an up-flow or down-flow as required by the desired reaction conditions or pre or post reaction processes.

The start of the reaction chamber has an attachment (not shown) that allows a solid plug 172 to be introduced into the reaction mixture flow. The plug is introduced at the in-feed end of the reaction tube and the attachment is designed to move into and out of the flow enabling a plug to be inserted into the reaction tube between lengths of feedstock. The plug 172 is dimensioned to be carried along the length of the reaction chamber by the flow of reagent mixture. The plug 172 is of sufficient diameter to lightly contact the inner surface walls of the reaction chamber thereby removing any solid material adhering to the reaction chamber wall. The reaction chamber is preferably fitted with a device on the out-flow end that isolates the cleaning plugs e.g. a cage or basket and returns them to the plug injector at the other end of the reaction chamber.

The region of the reaction chamber 110 where electromagnetic radiation is introduced into the chamber is made of material that is transparent to that radiation. The reaction chamber is constructed from material that is resistant to the conditions produced by the reaction materials in the mixture, the conditions produced by the reactions being induced and all by-products of those reactions. This reaction chamber construction material may or may not include quartz, glass or other ceramics.

The microwave power supply 130 is provided by a magnetron or klystron valve system. The microwave power supply 130 is fitted with its own control system which is integrated with the system microprocessor control unit 150. Microwaves from the supply 130 are guided through a waveguide 132, to the microwave cavity 140 and subsequently to the reaction tube 110. The

RECTIFIED SHEET (RULE 91) ISA/EP microwave cavity 140 completely surrounds the reaction tube 110. The waveguide 132 provides the means for the microwaves to pass from the source 130 to circular section 140. The design of this preferred embodiment enables a standing wave to be produced within the circular part of the wave guide 132 and so to be focused in the middle of the reaction tube 110 (see Figure 3).

In the preferred embodiment the custom electronics that integrate control over all components of the system has been built around a Rabbit microprocessor 150; this gives the ability to add other controls or monitoring, and readily alter operational procedures should the need arise e.g. during up scaling of the process. The microprocessor control system 150 monitors and controls in- feed speed using an in-feed control 152; which is used to set and alter the microwave power 154.

Microprocessor control system 150 monitors water flow 156 when required using data from the water flow meter 62; and reaction tube temperature 158, that is measured by thermopile 162. Magnetron temperature 134 is measured by a thermistor 136. All temperature readings are sent to and monitored by the microprocessor control system 150. Processing data and parameters are preferably stored in a memory 180 provided in the microprocessor 150.

Referring now to Figures 1 and 4, water cooling 160 is provided by loops of 6mm copper water pipe and the flow of water and the thermal protection provided to the microwave cavity 140 is measured using a flow meter 162 and modified to ensure adequate cooling water flow. The microwave cavity 140 also has two 12mm OD ports, one central and another 40mm downstream (not shown), to enable the external temperature of the reaction tube to be monitored.

RECTIFIED SHEET (RULE 91) ISA/EP The dimensions of the sleeve shields are tuned to the microwave frequency being delivered to the microwave cavity 140 to prevent leakage of microwave radiation from the cavity.

The dimensions quoted above concern the preferred embodiment operating at a microwave frequency of 2.45 GHz. A thermopile detector 142 is included for this purpose. Calibration is achieved by making measurements on an open oven that may be set to known temperatures, as shown in Figure 6. A simpler linear fit is shown for the operating region 400-600 °C.

To enhance the usefulness of the thermopile 142, the area of the reaction tube 110 that the thermopile views is preferably blackened so emissivity is 1 .0.

A thermistor 136 is preferably attached to the microwave magnetron housing at monitor the temperature therein ; this is calibrated using a thermocouple meter.

The microwave cavity 140 has been designed to maximise the continuous flow of material through it. To ensure this the cavity has been fitted with guide sleeves shields 145 at each end so that microwave energy is focused into the centre of reaction tube 110 which passes through microwave cavity. The dimensions of the guide sleeves must be tuned to the microwave frequency being used to minimise loss of microwave energy.

In the preferred embodiment being used to illustrate the invention in figures 1 through 4, the sleeve. Dimensions are chosen to minimise leakage of microwave energy from the cavity 140, (see table below for details).

Two different microwave frequencies have been used in experimentation and the following table summarises the results of this design for each:

RECTIFIED SHEET (RULE 91) ISA/EP Microwave frequency 2.45 GHz 915 MHz

Diameter of cavity 76 mm 203 mm

Length of cavity 97 mm 268 mm

Diameter of sleeves/shields 40.5 mm 80 mm

Length of sleeves 190 mm 350 mm

OD of reaction tube 31.75 76.2 mm

ID of reaction tube 25.4 mm 69 mm

Length of reaction tube 610 mm 1 100 mm

Performance of the equipment was checked with known material.

Microwave ovens, including this apparatus, should not be operated without absorbing material in the cavity/oven. The reason for this is that the unabsorbed energy will be directed back into the microwave magnetron, causing it to overheat, and discharge. This will eventually destroy the magnetron.

It was calculated that leakage was about 100,000 times the design level because of this dielectric mismatch.

In the first test, water at measured flow rate of about 1 litre/min was passed through a 6mm OD (outside diameter) glass tube positioned centrally in the alumina tube. Using a thermocouple gauge on the outflow, the temperature rise in the water was measured at various microwave power levels set by the microprocessor. The power absorbed by the water was calculated from the specific heat and temperature rise. The results are shown in Figure 7.

Given that the microwave magnetron power is rated at 1200 watts, Figure 7 shows that the microwave power is highly focussed to the centre of the cavity. Conductivity of the water column caused it to act as an antenna, and there was an unacceptable amount of microwave leakage from the ends of the

RECTIFIED SHEET (RULE 91) ISA/EP sleeves. In the latter trials, microwave leakage was at design levels, and was not of concern.

A second test was conducted using dry sand, mixed with 10% ground carbon, in a crucible. The crucible was carefully placed in the centre of the reaction tube. An Ircon Modline R14005 (Trade Mark) two colour pyrometer was located at one of the open ends of the reaction tube to enable monitoring of the reaction. Microwave power was set to only 40%, the pyrometer measured temperatures up to 1350 °C. A white glow from the crucible was observed by eye, and on recovery, the sand had fused into a solid, light ball rather like pumice. The fused sand mapped the zone into which the microwave energy had been focused.

Preferably, a thermistor is used to measure and report the magnetron wall temperature, the software being programmed to switch the magnetron off should overheating be detected.

The absorption of microwave energy results in dielectric heating and this is caused by dipole rotation. Molecular rotation occurs in materials containing polar molecules that have electric dipole moments that will attempt to align themselves in an electromagnetic field. If the field is oscillating, as in an electromagnetic wave, the molecules rotate to try and maintain alignment with the continuously changing field.

However the molecular movement may lag behind the electromagnetic field. This lag is measured as the dielectric loss constant. The oscillations induced in the target molecules are also measured as a rise in temperature. Therefore a material that has a high dielectric loss constant (when irradiated with microwave radiation) exhibits a rapid rise in temperature. It should be noted that the dielectric loss constant of a particular material changes with both temperature. Microwaves of 2.45 GHz frequency used in the preferred embodiment used to illustrate the system operate most effectively on liquid water because of the inherent polarity of the water molecules, but this has

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negligible effect on fats and sugars because of their lower polarity or frozen water because of the inability of the molecules to move within the ice crystal structure.

Microwave ovens, including this apparatus, should not be operated without absorbing material in the cavity/oven. The reason for this is that the unabsorbed energy will be directed back into the microwave magnetron, causing it to overheat, and discharge. This will eventually destroy the magnetron. Similarly, the material in the cavity should not have a very large dielectric constant, nor should the material have a high conductivity. If the cavity is filled with water, the large dielectric constant disturbs the electromagnetic field, and too much energy is transmitted back to the magnetron. This problem is countered in this invention by inserting an appropriately tuned microwave circulator, 3 stub tuner and dead load into the waveguide 136 between the microwave generator 132 and the microwave cavity 140.

In the event that the feedstock has a low dielectric loss constant (for example as is the case with the feedstock mentioned elsewhere in this document i.e. waste materials from humans and animals), an additive such as carbon powder can be added to ensure good microwave absorption. This increases the dielectric constant to enable better adsorption of the microwaves. In this document a high dielectric loss constant additive that is designed to improve the microwave energy absorption of the feedstock is referred to as a microwave coupling agent or just coupling agent.

Materials other than carbon can be used but as carbon is cheap and readily available and is an element contained in the feedstock it is preferred. Carbon is a product of the pyrolysis of organic material and can therefore be recycled back to the feedstock as a microwave coupling agent.

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A display panel is provided either as a front panel of an electronics cabinet or electrically connected thereto, shows various parameters that an operator may wish to visually check prior to starting a reaction or during a reaction process. The parameters include: the %microwave power set 154; the alumina tube temperature 158 (measured by thermopile); status of microwave power - whether off or on preferably using both a 'word' visual and an LED to indicate this; cooling water flow in litres/min 156; the magnetron wall temperature 134; and the error state. A pulsing colon light is provided to indicate that the microprocessor is working. Various connectors can be provided to enable networking of more than one apparatus or remote monitoring or storage of the process parameters.

In use, the apparatus is initially switched on (both control electronics and microwave power supply). Next the cooling water is turned on and the flow rate established. The microwave power setting is checked before pressing the microwave power button on. For safety a number of error states have been identified and when these are detected by t e control electronics the microwave power is turned off. One such error state is insufficient cooling water, another that the magnetron casing is too hot (above around 40°C).

The preferred embodiment is for the target feedstock and any additives to be presented to the chemical reactor as extruded rods. This invention includes the preparation and extrusion of feedstock that is typically in the form of extruded rods. This invention also includes equipment for storing extruded feed rods as well as equipment that can offer the rod to the chemical reactor assembly as required so rendering the chemical reaction as a continuous flow process. For the feedstock used which in this case was recovered waste biological material, a ffuidizing or lubricating agent had been added to enable extrusion of feedstock rods. This agent may well be, but need not be limited to, the tarry component of the liquid products of the pyrofysis process and/or creosote.

RECTIFIED SHEET (RULE 91) ISA/EP To enable a continuous process, the in-feed and out-feed need to be dimensioned and arranged so as to exclude air, as the material passes through for pyrolysis. Leakage of microwaves from the shields is preferably monitored and mitigated using additional Faraday cages, where necessary.

In addition, the temperature of the magnetron is important as overheating results in switching equipment off thus, prevention of reflection of microwave energy back into the magnetron is therefore important. One way to do this is to monitor the dielectric constant of the feedstock and reject it if it is too high. Alternatively or additionally, a microwave circulator, 3 stub tuner and dead load assembly is incorporated into the waveguide.

The simple flow-through reactor will allow increased productivity that will allow the energy transfer to chemical reaction advantages offered by electromagnetic radiation to be applied on an industrial scale. In addition, the flow-through reaction tube can be easily cleaned, by-products removed from deposits of the chemical reaction, by forcing a simple plug (referred to as a 'pig ) along the tube. This cleaning action can be undertaken without interrupting the chemical reaction or loss of productivity associated with many other cleaning systems.

The transfer of energy into the reaction tube by a standing electromagnetic wave offers the opportunity to deliver the same amount of energy across the entire reaction zone being heated by the radiation. This standing wave design also allows for the absolute amount of energy being transferred, being subject to far greater control than offered by a multi-mode electromagnetic energy transfer, or traditional conductive or convective heat transfer processes.

The large gap between the outer wall of the reaction tube 110 and the inner wall of the microwave cavity and/or sleeve shield guides means that reaction tubes designed for a wide range of chemical reactions and processes can be accommodated without causing thermal damage to the microwave cavity.

RECTIFIED SHEET (RULE 91) ISA/EP The water cooling coils 160 around the microwave cavity 140 are designed to keep the operating conditions of this apparatus within accepted limits. This degree of control over operating conditions may allows the waveguide 132 and microwave cavity 140 and sleeve shield tubes 145 to be made out of cost effective materials such as copper or aluminium.

An industrial process using electromagnetic energy transfer and a reaction tube of this design can easily be further scaled up by operating a number of these reactor channels in parallel. This is in comparison with the traditional method of scaling up a process by adopting a larger single reaction chamber. Scale-up by increasing the size of a single channel often results in different reaction conditions and different reaction products or efficiencies. These problems are avoided by scale-up of the number of reaction channels.

In addition to carefully selecting process parameters, optimisation of a reaction can be assisted using various processing additives. Thus, a second aspect of the invention relates to the transfer of energy through the agency of electromagnetic radiation (ER) to reduce the average molecular weight of a target substrate. Such energy transfer can be achieved over a wide range of ER wavelengths; this invention includes, but is not limited to the ER wavelength range known as microwave radiation (MR). The energy transfer process includes but is not limited to the process of Pyrolysis.

Pyrolysis will in this document be cited for illustrative purposes only and it is intended that the illustration be applied to all other processes involving the disruption of the chemical bonding of organic material through the application of thermal energy.

This invention includes, but is not limited to the ER transfer of energy to material commonly deem waste. Waste streams that may be subject to this invention include but are not limited to those sou reed from municipal entities such as cities. For the purpose of illustration the terms 'waste', 'waste

RECTIFIED SHEET (RULE 91) ISA/EP stream', 'substrate', 'reactants', 'reagents' and 'biological raw materials' may be used in this document to describe the starting material. In all cases it is intended that such illustrations are extended to multifarious raw material feeds to which the process could be applied.

This invention includes the introduction into the target substrate one or more 'Coupling Agents' (CA) which will improve or control the efficient absorption and transfer as heat, of the irradiating ER. Such CAs include, but are not limited to; water, steam, carbon dioxide, carbon black, graphite and/or coke.

The invention includes the introduction into the target substrate of any agent or agents needed to deliver the range or quality of products targeted by the process. These agents may be, but are not limited to, catalysts to affect, promote or control the rupture of the chemical bonds of the substrate; catalysts that promote further reactions of material that result from the rupture of the chemical bonds of the substrate, and/or materials that affect or control the activity of such catalytic agents.

The introduced agents may include material that suppress undesired side reactions or aid in the recovery, isolation of a desired product, isolation or nullification of an undesired product, or offer preferred material handling aspects to the substrate. In the process of pyrolysis, ignition is an example of a side reaction that may be suppressed by the introduction of a gas that displaces entrained air or oxygen.

ER has the ability to transfer energy into a volume of the target feedstock, unlike the other energy transfer mechanisms conduction and convection, which are limited to transferring energy through the surface contact area between the heat transfer medium and the target substrate. This provides ER with the ability to transfer precisely and controllably requisite and generally uniform energy to the substrate in the process reaction zone. Precise and even control of the energy delivery and therefore the heating process may optimise specification of the output products of the process. Therefore ER

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provides the opportunity to deliver higher value products than could easily be output from the same process using traditional energy delivery mechanisms.

Modern technology allows for the efficient generation of ER. This, coupled with direction and control of ER in the reaction zone, and the recycling of process energy, offers means in this invention to improve energy efficiencies in waste chemical processors.

Substrates which contain materials with low heat transfer coefficients impose further inefficiencies or slow processing times when traditional heat transfer mechanisms are used. Often, these factors alone make processing some substrates marginal or uneconomic. Through the use of suitable 'Coupling Agents', ER energy transfer can be applied to a much wider range of substrates than could be considered viable with the traditional approach to the process.

Because the ER transfer of energy is related to the irradiated volume of substrate rather than the contact area of the conductive heat transfer mechanism, processes utilizing ER heating can be rescaled to fit the substrate supply without encountering significant changes in process efficiency and/or capital cost of the process plant. This allows another aim of the present invention the process to be applied economically to much smaller substrate streams than can be targeted by conductively heated systems.

(n addition, this aspect of the invention includes the use of accessory processes which operate to increase or concentrate desirable material in the substrate prior to its introduction into the main process. Such accessory processes include, but are not limited to; density separation, distillation, azeotropic distillation, and/or solvent extraction.

The invention includes accessory processes to the main process that improve or optimize the physical contact between the substrate and any/all introduced

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agents. These accessory processes include, but are not limited to; ultrasonic treatment, induced turbulent flow and/or high sheer mixing.

The invention includes accessory processes to the main process that 'fluidize' or lubricate the substrate. Such accessory processes include, but are not limited to; Meit Flow, Flow Control media, and/ or Viscosity Modifiers that assist the precise metering of the movement of substrate through, and product from the main process.

The invention includes accessory processes to the main process that; isolate products, condition products for further processes; isolate CA or other agents that may have been introduced as part of a accessory process or processes, isolate agent(s) that may be used in an accessory process or processes, and/ or isolate agent(s) that may be used to recycle process energy to any of the accessory processes. These product isolation accessories may include: fractional condensation, crystalisation, calthration and/or electrostatic precipitation.

The invention includes metering of the movement of the substrate into a reaction zone in which the ER energy is transferred to the substrate. The invention covers aspects of the design of the reaction zone that affects efficient transfer of the ER energy to the substrate in the zone, movement of the substrate into and products out of the reaction zone.

The heating of organic material in the absence of air or oxygen, or in conditions where the air or oxygen supply is severely restricted, resulting in the production of lower molecular weight materials, may be known as pyrolysis, thermolysis or gasification or may be given some other process title. For the purpose of this document the process described above, or any similar processes, will be referred to as 'pyrolysis'.

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Referring now to Figure 8, pyrolysis 302, as applied to biological materials 300, yields a mixture of gases 310, a mixture of liquids 400 arid a carbonaceous solid 500.

The gas mixture 310 has a significant calorific value when combusted. This high calorific gas mixture may, be used to fuel 320 the pyrolysis process, and/or any 330 of the heat requiring processes described below, thereby rendering the production of the materials used to manufacture bio-green carbon electrodes, a carbon neutral process.

As well as the gases, other products of the microwave induced pyrolysis process described by this invention can be further processed using the electromagnetic energy transfer system and apparatus that is the subject of this invention. Descriptions of further processing of liquid and solid pyrolysis products are described in the following paragraphs.

The liquid mixture 400 isolated from the pyrolysis of biological material, ff left to stand without agitation, may separate into two layers. One layer is an oily water immiscible liquid 410 that can be separated from a hydrophilic layer 412 by simple decanting 414. This oily liquid 4 0, whether removed from, or used partially or wholly in the biological pyrolysis liquid mixture, may be further treated to produce a material similar in its characteristics to petroleum or coal derived pitch. This material is referred to herein as bio-pitch 420.

Bio-pitch 420 is prepared from the oily liquid 410 described above by the removal of the volatile components from that liquid, for example by distillation, which itself may, be carried out under reduced atmospheric pressure, or vacuum conditions. The highly viscous liquid that remains after volatile components have been removed is bio-pitch 420.

The carbonaceous solid material 500 resulting from the pyrolysis 302 of biological material 300 may be converted into a material (bio-coke 550) similar

RECTIFIED SHEET (RULE 91) ISA/EP in character to the petroleum or coal derived coke presently used to manufacture green carbon electrodes, by one or more heat treatment processes 520,530, for example carried out using the microwave heating system described herein. However if this novel heating system is used the much more even heating can result in a higher quality end product.

The initial heat treatment process or process applied to the carbonaceous solid material 500 may be designed to remove volatile components 520, for example those remaining in the carbonaceous solid material. Initial heat treatment processes benefit from precise application of heat to raise the temperature of the carbonaceous material, either by a series of steps, or in one step, to a point below the onset of annealing of the material.

These de-volatilisation processes may be carried out under vacuum, or under reduced atmospheric pressure. For example under atmospheric pressures greater than one bar, or in an atmosphere composed of a specific gas or gas mixture. The gas or gas mixture may include, for example, carbon monoxide, carbon dioxide, nitrogen, air, alkenes, alkanes, hydrogen and/or steam.

The coke conversion process 530 may, include one or more calcining heat treatment processes. These calcining processes may heat in one or more closely controlled steps with at least one of those steps taking place at temperatures above the annealing point of the material. Any of the calcining processes may be carried out under vacuum, reduced or elevated atmospheric pressure conditions. Any of the calcining processes may be carried out under special gaseous atmospheres. These gaseous atmospheres may include, or be a mixture of, but are not limited to air, nitrogen, carbon monoxide, carbon dioxide, pyrolysis gas products, hydrogen or water.

The heating processes described above may be carried out by, but is not limited to, the energy transfer processes described in this document.

RECTIFIED SHEET (RULE 91) ISA/EP A fourth aspect of the invention relates to the sequestration of carbon through the pyrolysis 302 of organic matter and in particular biological waste 300 to yield an environmentally stable carbon-rich product 500, 550. This aspect of the present invention relates to treatment of human and animal derived body waste streams in a manner that substantially avoids effluent discharge problems.

The process of pyrolysis, particularly when delivered under very tightly controlled conditions offered by microwave induced pyrolysis, such as is detailed within this document, organic material can be converted to a stable carbonaceous product 550 which can have a very positive effect when used as a soil conditioning medium.

When applied to biological waste streams 300, the present invention converts a significant portion of that material into a solid form 480, 500, 550 that is stable over an extended period of time, thereby effectively and efficiency sequestering carbon dioxide from the atmosphere. Additionally, the process whereby solid, bio-char is sequestered also yields an effective soil conditioning agent as adding bio-char to a nutrient deficient soil will reversibly bind nutrients making them available to support plant growth thereby improving the fertility of the soil. Binding nutrients in the soil have the effect of reducing the migration of these compounds into, and the subsequent pollution of, fresh water and marine aquifers.

A further advantage of the present invention is consequently its application to untreated or partly treated biological waste streams 300, including the re- treatment or modification of a carbon-rich carbon-sequestering solid, which itself may or may not have been produced using the invention, to improve the properties of the treated product as a nutrient retaining soil additive. The invention also offers an environmentally attractive alternative to the landfill disposal of sewage sludge by-products of the most sophisticated waste water

RECTIFIED SHEET (RULE 91) ISA/EP treatment system. The invention can therefore be easily integrated into existing treatment system or be used as a stand-alone process.

Furthermore, the present invention is readily scalable. It can be deployed on a scale that addresses the needs of a modest sized intense animal husbandry operation or the effluent from a small community or scaled-up to contribute to a city sewage treatment system.

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The 'carbon cycle' has most carbonj dioxide in the atmosphere being absorbed by plants and included in their tissues. The plant tissues may be passed through the food chain but eventually some organism will try and access the energy stored in the carbon chemical bonds of the tissue through the process of respiration. During the respiration process energy is extracted by oxidising the tissue carbon to carbon dioxide which is dumped back into the atmosphere. Sequestration breaks; the carbon cycle by converting the tissue carbon to form which is chemically and biologically stable and is not easily oxidised to carbon dioxide. Natural carbon sequestration has resulted in large deposits of coal or oil.

Pyrolysis 302 of biological waste material 300 produces a carbon rich solid product 550. If this product is resistant to further oxidation under normal environmental conditions it can be regarded as sequestered carbon.

It is to be appreciated that these Figures are for illustration purposes only and other configurations are possible.

The invention has been described by way of several embodiments, with modifications and alternatives, but having read and understood this description, further embodiments and modifications will be apparent to those skilled in the art. All such embodiments and modifications are intended to fall within the scope of the present invention as defined in the cfaims

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