GB2614533A

GB2614533A - Biomass pyrolysis apparatus

Info

Publication number: GB2614533A
Application number: GB2119117.6A
Authority: GB
Inventors: John Clarke Lionel; Rhys Thomas David
Original assignee: Bionerg Ltd
Current assignee: Bionerg Ltd
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2023-07-12
Also published as: GB202119117D0

Abstract

There is provided a biomass pyrolysis apparatus (30) for carrying out a biochar production process, the biomass pyrolysis apparatus (30) comprising: a biochar kiln (32); at least one temperature sensor (34) configured to, in use, measure a temperature inside the biochar kiln (32); at least one weight sensor (36) operably coupled to the biochar kiln (32) so that the or each weight sensor (36) is configured to, in use, measure a change in weight of biomass inside the biochar kiln (32); and a data capture device (38) configured to, in use, record temperature data obtained by the or each temperature sensor (34) and weight data obtained by the or each weight sensor (36). There is also provided a biochar kiln comprising a trough and a heat shield wall, wherein the trough is shaped as a quadrilateral frustum, wherein the heat shield wall is suspended from walls of the trough so that the heat shield wall surrounds the trough.

Description

BIOMASS PYROLYSIS APPARATUS

The invention relates to a biomass pyrolysis apparatus for carrying out a biochar production process, a biochar kiln, a biomass pyrolysis system, a method of characterising a biochar production process carried out by a biomass pyrolysis apparatus and a method of characterising a plurality of biochar production processes respectively carried out by a plurality of biomass pyrolysis apparatus.

Biochar is produced by a process called pyrolysis that involves heating, but not burning, biomass to high temperatures in a low oxygen environment. By using the energy available from within the biomass feedstock to raise the temperature together with the manual effort of adding fresh layers of biomass into a kiln successively over a number of hours, the required temperatures and low oxygen conditions are maintained to generate highly stable, high quality biochar. The biochar is quenched to halt the pyrolysis process at an appropriate moment so that it does not continue to smoulder and reduce to ash. This may be achieved by quenching with water, by snuffing out with a lid or by adding a layer of soil to the top layer of the biomass.

According to a first aspect of the invention, there is provided a biomass pyrolysis apparatus for carrying out a biochar production process, the biomass pyrolysis apparatus comprising: a biochar kiln; at least one temperature sensor configured to, in use, measure a temperature inside the biochar kiln; at least one weight sensor operably coupled to the biochar kiln so that the or each weight sensor is configured to, in use, measure a change in weight of biomass inside the biochar kiln; and a data capture device configured to, in use, record temperature data obtained by the or each temperature sensor and weight data obtained by the or each weight 30 sensor.

The configuration of the biomass pyrolysis apparatus of the invention enables characterisation of the biochar production process to monitor apparatus performance and, if necessary, introduce improvements to the process. In particular, the invention provides a straightforward and relatively inexpensive way to monitor biochar production in rural or remote locations that may have limited access to specialist advisors or equipment. This in turn provides quality assurance in order to, for example, meet carbon capture and certification requirements.

In embodiments of the invention, the temperature data may include temperature time-series data. This enables real-time characterisation of the biochar production process in terms of changes in temperature over time.

The or each temperature sensor may be configured in various ways to enable measurement of a temperature (or temperatures) inside the biochar kiln. In a preferred embodiment of the invention, the or each temperature sensor may be operably coupled to the biochar kiln so that the or each temperature sensor is configured to, in use, measure a temperature inside the biochar kiln.

The biomass pyrolysis apparatus may include first and second temperature sensors, wherein the first and second temperature sensors may be configured to, in use, measure temperatures at different heights inside the biochar kiln. Preferably the first and second temperature sensors may be operably coupled to the biochar kiln at different heights so that the first and second temperature sensors are configured to, in use, measure temperatures at different heights inside the biochar kiln. The ability to perform in-situ measurement of temperatures at different heights inside the biochar kiln enables accurate characterisation of the different stages of the biochar production process from start to end.

Preferably the data capture device may be configured to, in use, start recording the temperature data obtained by the or each temperature sensor and the weight data obtained by the or each weight sensor when the lower of the first and second temperature sensors detects a first predefined temperature above ambient temperature and/or stop recording the temperature data obtained by the or each temperature sensor and the weight data obtained by the or each weight sensor when, or following a pre-determined period of time after, the lower of the first and second temperature sensors detects a second predefined temperature above ambient temperature. The former automatically takes place when the biochar kiln is heated up to a predefined temperature at the start of the biochar production process, while the latter automatically takes place after a predetermined period of time following when the biochar kiln cools down to a predefined temperature at the end of the biochar production process. This not only ensures that the start and/or end points of the biochar production process are properly captured by the data capture device but provides a way of reducing energy consumption by ensuring that the data capture device only records temperature and weight data when required to do so. The first and second predefined temperatures above ambient temperature may be the same temperature or may be different temperatures.

In further embodiments of the invention, the weight data may include weight time-series data. This enables real-time characterisation of the biochar production process in terms of changes in biomass weight over time arising from biomass addition due to loading and biomass reduction due to pyrolysis.

Optionally the biomass pyrolysis apparatus may include a plurality of weight sensors operably coupled to different points of the biochar kiln so that the plurality of weight sensors is configured to, in use, measure a change in weight of biomass inside the biochar kiln. This not only enables a more accurate measurement of the change in weight of biomass in larger biochar kilns but also permits the use of smaller weight sensors, as opposed to a single large weight sensor (e.g. a weight scale), to accommodate the larger biochar kilns.

In further embodiments of the invention, the data capture device may include a wireless transmitter for transmitting the recorded temperature and weight data. This allows the recorded temperature and weight data to be retrieved from the data capture device from a distance, which is not only beneficial from a safety perspective but also permits real-time retrieval of the recorded temperature and weight data instead of waiting to retrieve the data from the data capture device after the end of the biochar production process.

Optionally the data capture device may include a switch operable to selectively turn the wireless transmitter on and off. Further optionally the biomass pyrolysis apparatus may include a magnetic device configured for magnetically operating the switch to selectively turn the wireless transmitter on and off. This prevents unauthorised retrieval of the recorded temperature and weight data from the data capture device.

In further embodiments of the invention, the data capture device may include an electronic reference identifier for identifying the biomass pyrolysis apparatus. Non-limiting examples of the reference identifier are described throughout the specification. The purpose of the reference identifier is to enable the recorded temperature and weight data to be linked to the correct data capture device and therefore the correct biomass pyrolysis apparatus, which is important to ensure proper characterisation and certification of the biochar production process.

The biochar kiln is preferably, but is not limited to, a flame curtain kiln or a retort kiln.

According to a second aspect of the invention, there is provided a biochar kiln comprising a trough and a heat shield wall, wherein the trough is shaped as a quadrilateral frustum (e.g. a pyramidal frustum), wherein the heat shield wall is suspended from walls of the trough so that the heat shield wall surrounds the trough.

The heat shield wall may include at least one overhang section that is arranged inwards towards the trough, wherein the or each overhang section is positioned above the trough. The or each overhang section may be fabricated by, e.g. bending, tilting or hemming a portion of the heat shield wall.

The trough's quadrilateral shape makes it more practical to manufacture the heat shield wall (such as cutting and welding), facilitates more efficient use of construction material, and makes it easier to transport and operate the biochar kiln.

In particular, the trough's quadrilateral shape makes it easier to design and manufacture the or each overhang section to have a greater level of overhang in order to improve upward flow of air more effectively into and towards the centre of the biochar kiln, which improves the vortex flow of potentially unburned gases from the biochar kiln to increase pyrolysis efficiency, reduce emissions and improve safety.

The biochar kiln may include a plurality of reinforcement members. The reinforcement members may be attached along the walls of the trough so as to reinforce the walls of the trough. Each reinforcement member may be attached or coupled to the heat shield wall. During the biochar production process, the walls of the trough may expand, contract or distort due to heating or quenching. The reinforcement members, assisted by their attachment to the surrounding heat shield wall, act to maintain the shape of the walls of the trough during heating and cooling cycles of the biochar production process.

The design of the biochar kiln of the invention permits minimisation of construction materials so as to reduce kiln weight, cost and carbon footprint relative to biochar production throughput.

According to a third aspect of the invention, there is provided a biomass pyrolysis apparatus according to any one of the first aspect of the invention and its embodiments wherein the biochar kiln is in accordance with any one of the second aspect of the invention and its embodiments.

The features and advantages of the preceding aspects of the invention and its embodiments apply mutatis mutandis to the biomass pyrolysis apparatus of the third aspect of the invention and its embodiments.

According to a fourth aspect of the invention, there is provided a biomass pyrolysis system comprising a biomass pyrolysis apparatus in accordance with any one of the first and third aspects of the invention and their embodiments, the biomass pyrolysis system including a processor, the biomass pyrolysis system configurable so that the processor receives the recorded temperature and weight data from the data capture device of the biomass pyrolysis apparatus, wherein the processor is programmed to process the recorded temperature and weight data to generate a characterisation profile of the biochar production process.

The features and advantages of the preceding aspects of the invention and their embodiments apply mutatis mutandis to the biomass pyrolysis system of the fourth aspect of the invention and its embodiments.

In addition, the inclusion of the processor in the biomass pyrolysis system of the invention enables automatic generation of the characterisation profile, which can then be used in subsequent analysis and processes. This reduces or eliminates the need for manual intervention to generate the characterisation profile.

In embodiments of the invention, the processor may be, may include or may form part of one or more of an electronic device, a portable electronic device, a portable telecommunications device, a mobile phone, a personal digital assistant, a tablet, a phablet, a laptop computer, a server, a cloud computing network, a smartphone, a smartwatch, smart eyewear, and a module for one or more of the same. It will be appreciated that references to a memory or a processor in this specification may encompass a plurality of memories or processors.

When the biomass pyrolysis system includes a plurality of biomass pyrolysis apparatus, each biomass pyrolysis apparatus in accordance with any one of the first and third aspects of the invention and their embodiments, the biomass pyrolysis system may be configurable so that the processor receives the recorded temperature and weight data from the data capture device of each of the plurality of biomass pyrolysis apparatus,

S

wherein the processor may be programmed to process the recorded temperature and weight data to generate a respective characterisation profile of the biochar production process carried out by each of the plurality of biomass pyrolysis apparatus.

The multiple biomass pyrolysis apparatus may be located at the same site or at different sites.

Gathering and aggregating the temperature and weight data from a distributed network of biomass pyrolysis apparatus in this manner enables a centralised approach to the characterisation of the biochar production processes of the multiple biomass pyrolysis apparatus that can overcome local quality assurance limitations whilst meeting stringent validation requirements of carbon capture methodologies. Furthermore, aggregation of multiple datasets provides a statistically robust source of apparatus performance data to permit the certification of carbon credits.

The processor may be local to or remote from the site of the biomass pyrolysis apparatus. For example, the processor may be or may form part of a computer, a smartphone or a tablet located in the vicinity of the biomass pyrolysis apparatus, or alternatively the processor may be a remote computer or server that is located in, for example, a different country.

Optionally the biomass pyrolysis system may be configurable so that the processor receives the recorded temperature and weight data from the or each data capture device via a telecommunications network. For example, the processor may be or may form part of a remote computer or server, and the recorded temperature and weight data is transmitted from the data capture device(s) to the remote computer or server via the telecommunications network, e.g. the internet. A mobile electronic device, such as a smartphone, a tablet or a laptop, may be used to connect the data capture device(s) to the telecommunications network.

It will be understood that, whilst it is possible for the processor to receive the recorded temperature and weight data from the data capture device(s) in real-time, the invention encompasses the storage of the recorded temperature and weight data in real-time and subsequent transmission of the recorded temperature and weight data to the processor at a later time or date. Also, the processor may be configured to receive the recorded temperature and weight data instantaneously or in predefined data series or data blocks. Individual time/data points can be interrogated in an ad-hoc manner for process monitoring purposes. In semi-automated operations carried out by an authorised user or personnel, the communication between the data capture device(s) and the processor may take place after the data has been captured in a data file.

According to a fifth aspect of the invention, there is provided a method of characterising a biochar production process carried out by a biomass pyrolysis apparatus, the biomass pyrolysis apparatus comprising: a biochar kiln; at least one temperature sensor configured to, in use, measure a temperature inside the biochar kiln; and at least one weight sensor operably coupled to the biochar kiln so that the or each weight sensor is configured to, in use, measure a change in weight of biomass inside the biochar kiln, wherein the method comprises the step of recording temperature data obtained by the or each temperature sensor and weight data obtained by the or each weight sensor.

The features and advantages of the preceding aspects of the invention and their embodiments apply mutatis mutandis to the method of the fifth aspect of the invention and its embodiments.

The method of the invention may include the step of processing the recorded temperature and weight data to generate a characterisation profile of the biochar production process.

In embodiments of the method of the invention, the biomass pyrolysis apparatus may include first and second temperature sensors, wherein the first and second temperature sensors may be configured to, in use, measure temperatures at different heights inside the biochar kiln. In such embodiments, the characterisation profile may include a decrease in temperature measured by the lower temperature sensor and an increase in temperature measured by the upper temperature sensor towards an end of the biochar production process.

In further embodiments of the method of the invention, the characterisation profile may include variations in biomass weight that indicate addition and reduction of biomass from the biochar kiln at different points of the biochar production process.

According to a sixth aspect of the invention, there is provided a method of characterising a plurality of biochar production processes respectively carried out by a plurality of biomass pyrolysis apparatus, the method comprising the steps of carrying out the method of any one of the fifth aspect of the invention and its embodiments in respect of each biomass pyrolysis apparatus, wherein the method includes the step of obtaining the recorded temperature and weight data of each of the plurality of biomass pyrolysis apparatus via a telecommunications network.

The features and advantages of the preceding aspects of the invention and their embodiments apply mutatis mutandis to the method of the sixth aspect of the invention and its embodiments.

The method of the invention may include the step of obtaining the recorded temperature and weight data and an electronic reference identifier of each of the plurality of biomass pyrolysis apparatus via the telecommunications network, wherein each of the plurality of biomass pyrolysis apparatus is associated with a respective unique electronic reference identifier.

It will be appreciated that the method according to embodiments of the invention may be performed using one or more biomass pyrolysis apparatus or systems according to embodiments of the invention.

It will also be appreciated that the use of the terms "first" and "second", and the like, in this patent specification is merely intended to help distinguish between similar features and is not intended to indicate the relative importance of one feature over another feature, unless otherwise specified.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, and the claims and/or the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and all features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

Preferred embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings in which: Figure 1 shows a biomass pyrolysis apparatus according to an embodiment of the invention; Figures 2 and 3 respectively show front and rear views of the biomass pyrolysis apparatus of Figure 1 when front and rear sections of a heat shield wall are omitted for illustrative purposes; Figures 4a, 4b and 5 respectively show front and top close-up views of suspension brackets and angle iron struts of the biomass pyrolysis apparatus of Figure 1; Figures 6 and 7 illustrate the manufacture of a biochar kiln from steel sheets; Figures 8 and 9 show inlet and outlet pipes connected to a base of a trough of a biochar kiln; Figure 10 shows a configuration of a data capture device, temperature sensors and weight sensors of the biomass pyrolysis apparatus of Figure 1; Figure 11 shows a thermocouple covered by a shielding bracket; Figure 12 shows a device for turning a wireless transmitter on and off; and Figures 13 to 15 respectively show characterisation profiles of biochar production processes.

The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interests of clarity and conciseness.

The following embodiments of the invention are described with reference to a flame curtain kiln (also known as a Kon-Tiki kiln) but it will be appreciated that the following embodiments of the invention apply mutatis mutandis to other biochar kilns, such as a retort kiln.

A biomass pyrolysis apparatus according to an embodiment of the invention is shown in Figure 1 and is designated generally by the reference numeral 30. The biomass pyrolysis apparatus 30 is for carrying out a biochar production process. The biomass pyrolysis apparatus 30 comprises a biochar kiln 32, a plurality of temperature sensors 34, a plurality of weight sensors 36 and a data capture device 38.

The biochar kiln 32 includes a trough 40, a heat shield wall 42 and a plurality of suspension brackets 44. The trough 40 is shaped as a rectangular pyramidal frustum.

In Figures 2 and 3, the trough 40 is supported on a steel frame 46 (such as a ladder) that itself is supported at three points by adjustable axle stands 48, which may be operated to tilt the trough 40 to assist drainage of water from the trough 40. Other types of support structures and equipment may be used to keep the trough 40 elevated above the ground.

The suspension brackets 44 are bolted or otherwise secured to the heat shield wall 42 and are arranged to engage top edges of walls 50 of the trough 40 so that the heat shield wall 42 is suspended from the walls 50 of the trough 40 so as to surround the trough 40, as shown in Figures 2 to 5. The suspension brackets 44 are dimensioned such that the heat shield wall 42 is spaced apart from the trough 40 to create an air flow channel 52 between the heat shield wall 42 and the walls 50 of the trough 40. Support rods 54 extending from the steel frame 46 may be attached to the heat shield wall 42 to provide additional reinforcement.

The heat shield wall 42 has an overall rectangular shape that is similar to the rectangular shape of the trough 40. A top rim 56 of the heat shield wall 42 is bent to form an overhang section that is tilted inwards towards the trough 40 and surrounds the trough 40. The overhang section is positioned above the trough 40, i.e. higher than the trough 40. Bottom edges 58 of the heat shield wall 42 are bent to tilt inwards towards the trough 40 to confer further rigidity to the heat shield wall 42. The tilted bottom edges 58 are positioned below the trough 40, i.e. lower than the trough 40. In the embodiment shown, the angle of tilt of the top rim 56 and the bottom edges 58 is 45° but the angle of tilt may vary in other embodiments. Alternatively the bottom edges 58 may be hemmed to confer the desired further rigidity to the heat shield wall 42 and also to prevent sharp bottom edges that could hurt a nearby user upon contact.

The heat shield wall 42 directs air to flow up the sides of the outwardly sloping walls 50 of the trough 40, while the tilted top rim 56 helps to direct the air to form vortices to maximise the amount of air flowing towards the centre of the trough 40 instead of escaping into the atmosphere above. At the same time the heat shield wall 42 acts as a safety wall to protect an operator from heat during the biochar production process.

The biochar kiln 32 includes a plurality of reinforcement members in the form of angle iron struts 60, as shown in Figures 2 to 5. The angle iron struts 60 are attached along the outside of the walls 50 of the trough 40, from the base of the trough 40 to the top of the trough 40, so as to reinforce the walls 50 of the trough 40. An end of each angle iron strut 60 protrudes above the top of the trough 40. The protruding end of each angle iron strut 60 is bolted or otherwise secured to a respective one of the suspension brackets 44. Since the suspension brackets 44 are attached to the surrounding, cooler heat shield wall 42, the configuration of the angle iron struts 60 and the suspension brackets 44 maintains the shape of the walls 50 of the trough 40, which would otherwise expand, contract or distort during heating and quenching steps of the biochar production process (e.g. without reinforcement, the walls 50 may splay out to form a U-shaped cross-sectional profile, away from their original truncated V-shaped cross-sectional profile. Even worse, without reinforcement, the walls 50 may buckle and collapse). As a result the trough 40 can be designed to use thinner walls 50 to reduce cost and weight because, despite the resulting drop in strength of the walls 50, the angle iron struts 60 provide the required reinforcement to maintain the shape of the walls 50 throughout multiple heating and cooling cycles. The number of reinforcement members on each side of the trough 40 may vary, e.g. it may be one, two, three, four, five or more. Furthermore the angle iron struts 60 provide minimal interference to vertical air flow between the walls 50 and the heat shield wall 42.

Figure 4a shows a configuration of the suspension brackets 44 having straight cantilever sections 45a that rest on top of the walls 50 of the trough 40. Figure 4b shows another configuration of the suspension brackets 44 having cantilever sections 45b that are shaped to follow the incline of the walls 50 of the trough 40 so that the walls 50 are arranged between the suspension brackets 44 and the angle iron struts 60.

The trough 40, the suspension brackets 44 and the heat shield wall 42 may be made of mild steel or stainless steel. The thickness of the walls 50 of the trough 40 may be 3 mm. The trough 40 and the suspension brackets 44 may be made from the same steel sheet 62, with the trough 40 made from a main portion 64 of the steel sheet and with the suspension brackets 44 being made from cut-out portions 66 of the steel sheet, as shown in Figure 6. The heat shield wall 42 may be made of another steel sheet 68, as shown in Figure 7. In the embodiment shown, the heat shield wall 42 is constructed of four separate walls 70, with a respective angle iron strut 72 bolted or otherwise secured to the outside of a respective one of the four walls 70, where the angle iron struts 72 are bolted or otherwise secured to each other to form the heat shield wall 42 from the four separate walls 70. The provision of the angle iron struts 72 provide the heat shield wall with the required strength to reinforce the walls 50 of the trough 40 via the suspension brackets 44 and the angle iron struts 60, which allows the walls 50 to expand and contract naturally during the biochar production process to reduce stress while providing sufficient support to prevent major failure of the overall shape of the trough 40. In contrast, a sufficiently strong reinforcement structure directly attached and positioned closer to the walls 50 of the trough 40 would not only interfere more with vertical air flow between the walls 50 and the heat shield wall 42 but also may introduce significant stresses and strains as the trough 40 is heated and cooled.

As shown in Figure 8, inlet and outlet pipes 74,76 are attached to a base of the trough 40 to permit the trough 40 to be filled with water via the inlet pipe 74 for quenching and to be drained via the outlet pipe 76 afterwards. The pipes 74,76 are dimensioned and positioned to be above a floor of the trough 40 to avoid damage during transportation. The pipes 74,76 may be threaded to permit attachment or fitment of taps or hoses. A water container 78 is connected to the inlet pipe 74 to fill the trough 40 with water. A water collector 80 is connected to the outlet pipe 76 to collect the drained water. Flow valves 82,84 are provided on the inlet and outlet pipes 74,76 to control the flow of water through the inlet and outlet pipes 74,76. The water can be recycled for multiple biochar production processes. In other embodiments, a single pipe may be used for filling and draining the trough 40. Alternatively the inlet pipe 74 may be replaced by multiple inlet pipes and/or the outlet pipe 76 may be replaced by multiple outlet pipes. In still other embodiments, a drain hole may additionally be included in the floor of the trough 40 so that the drain hole can be used to fully drain water from the trough 40, which may be present as a result of rainfall despite not being in use. A bolt and nut arrangement may be used to make the drain hole watertight during use, where the bolt is removable to permit water to drain through the drain hole. In still further other embodiments, one of the walls 50 of the trough 40 may be shaped to have a vertical wall section 86, where the inlet and outlet pipes 74,76 are connected to the vertical wall section 86, as shown in Figure 9.

Figure 10 shows a configuration of the data capture device 38, the thermocouples 34 and the weight sensors 36 of the biomass pyrolysis apparatus 30.

The plurality of temperature sensors 34 are in the form of first and second thermocouples 34. The first and second thermocouples 34 are inserted into holes in a wall 50 of the trough 40 at different heights, one above the other, so that the first and second thermocouples 34 are configured to, in use, measure temperatures at different heights inside the trough 40. The thermocouples 34 are threaded so that they can be secured in place using nuts. It is envisaged that, in other embodiments of the invention, a different number, a different type and/or a different configuration of temperature sensors may be employed.

Each thermocouple 34 is covered by a metal shielding bracket 88 for protection against physical damage within the trough 40, as shown in Figure 11. The metal shielding bracket 88 includes an opening to permit convection of heat past the thermocouples 34 for measurement purposes. The metal shielding bracket 88 is bolted or otherwise secured to the wall 50 of the trough 40.

The plurality of weight sensors 36 are in the form of three weight sensors 36. Each weight sensor 36 is mounted between an adjustable axle stand 48 and the steel frame 46. This enables the plurality of weight sensors 36 to, in use, measure a change in weight of biomass inside the trough 40. It is envisaged that, in other embodiments of the invention, a different number, a different type and/or a different configuration of weight sensors 36 may be employed.

The data capture device 38 is mounted onto a thermally insulative plate 90 to protect the data capture device 38 from heat. The data capture device 38 is coupled to the thermocouples 34 and the weight sensors 36 using wired electrical connections in order to enable transmission of data from the sensors to the data capture device 38. In other embodiments, the data capture device 38 may be coupled to the thermocouples 34 and the weight sensors 36 using wireless connections.

The data capture device 38 includes analogue to digital converters for converting the analogue electrical signals from the sensors into digital electrical signals, a timer to enable recordal of temperature and weight time-series data, and a wireless transmitter (e.g. a Wi-Fi transmitter) assembled on a printed circuit board. In this way a data capture device 38 can record temperature data obtained by the thermocouples 34 and weight data obtained by the weight sensors 36 during the biochar production process, and transmit data to an external receiver.

The data capture device 38 includes an electronic reference identifier, such as an alphanumeric serial code, that is unique to the data capture device 38 and the biomass pyrolysis apparatus 30. Including the electronic reference identifier in any data transmitted by the data capture device 38 allows the transmitted data to be linked to the correct data capture device 38 and therefore the correct biomass pyrolysis apparatus 30.

The data capture device 38 includes an in-built battery that can be recharged by connecting to an external battery or using a renewable energy device, such as a solar panel. To conserve energy, the data capture device 38 may be programmed to be in deep sleep mode when it is not required to capture or transmit data. The level of charge in the battery may be displayed using an external indicator that responds to the press of a test button.

A secure method of switching the wireless transmitter on and off is provided in order to ensure that data is collected only by authorised personnel. As shown in Figure 12, a bracket 92 containing a slot is provided, wherein a magnetic device 94 in the form of a token with a magnet can be fitted into and rotated within the slot. A Hall Effect sensor in the data capture device 38 senses the magnet and provides a control signal that depends on the sensed polarity of the magnet, which changes by rotating the token inside the slot. This in effect enables the Hall Effect sensor to act as a switch to selectively turn the wireless transmitter on and off, e.g. switch between two transmission modes: the transmission of instantaneous data; and the transmission of a complete data series or data block. Turning the wireless transmitter on permits transmission of data from the data capture device 38, while turning the wireless transmitter off disables transmission of data from the data capture device 38 to prevent unauthorised extraction of data and reduce battery energy consumption.

Preferably the data capture device 38 is programmed to, in use, start recording the temperature data obtained by the thermocouples 34 and the weight data obtained by the weight sensors 36 when the lower of the thermocouples 34 detects a predefined temperature (e.g. 50°C) that is above ambient temperature, because the temperature towards the bottom of the inside of the trough 40 will be higher than the temperature towards the top of the inside of the trough 40 at the start of the biochar production process. This allows the temperature inside the trough 40 to act as a trigger to initiate data capture by the data capture device 38.

Preferably the data capture device 38 is programmed to, in use, stop recording the temperature data obtained by the thermocouples 34 and the weight data obtained by the weight sensors 36 when the lower of the thermocouples 34 detects a predefined temperature (e.g. 50°C) that is above ambient temperature, as the inside of the trough 40 cools down towards the end of the biochar production process. This allows the temperature inside the trough 40 to act as a trigger to stop data capture by the data capture device 38. Alternatively the data capture device may be programmed to continue capturing the temperature and weight data for a set period of time following the trigger to stop data capture, to ensure that the full pyrolysis process throughout the biochar kiln is fully characterised before the data capture ends.

The data capture device 38 may include a data storage device or medium for storing the recorded temperature and weight data as well as the associated time data in the form of data files. The data capture device 38 may be programmed to, upon turn-on of the wireless transmitter, automatically transmit a saved data file or wait for a incoming command before transmitting a saved data file.

Data may be captured by the data capture device 38 at regular intervals (e.g. a measurement per minute).

Figures 13 and 14 show temperature time-series data recorded from different biochar production processes. As mentioned above, the temperature towards the bottom of the inside of the trough 40 will be higher than the temperature towards the top of the inside of the trough 40 at the start of the biochar production process. This is because the trough 40 is not fully loaded with biomass at the start of the biochar production process, which means that the higher thermocouple 34 is unable to accurately detect the temperature of the biochar production process. As more biomass is added to the trough 40, the build-up of biomass inside the trough 40 then enables the higher thermocouple 34 to more accurately detect the temperature of the biochar production process. In this manner, in addition to measuring the pyrolysis temperatures of the biochar production process, the temperature measurements 96,98 by the two thermocouples 34 at lower and upper regions inside the trough 40 provide a way of tracking the loading of biomass from the bottom up over the duration of the biochar production process, typically several hours. Different ways of loading the biomass into the trough 40 and the associated heat and flames can result in different thermocouple 34 temperature measurement profiles.

A higher number and/or a different arrangement of the thermocouples 34 may be used to provide more temperature information about the pyrolysis temperatures and the loading of the biomass into the trough 40 over time.

Figures 13 to 15 show weight time-series data 100 recorded from different biochar production processes. As more biomass is added to the trough 40, the build-up of biomass inside the trough 40 is detected by the weight sensors 36 as an increase in biomass weight inside the trough 40. At the same time, the pyrolysis of the biomass results in part of the biomass being released as energy and the other part of the biomass being converted into biochar. The resulting reduction in biomass inside the trough 40 is detected by the weight sensors 36 as a decrease in biomass weight inside the trough 40. Due to the time intervals between measurements, the increases in biomass weight inside the trough 40 are detected as step ups in weight 102, while the decreases in biomass weight inside the trough 40 are detected as step downs in weight 104. In this manner the weight measurements by the weight sensors 36 provide a way of tracking the loading of biomass into the trough 40 and the pyrolysis of the biomass over the duration of the biochar production process.

Quenching the biomass with water initiates a rapid drop in temperature alongside a rapid increase in weight that can be detected by the thermocouples 34 and the weight sensors 36.

Using the wireless transmitter, the data capture device 38 transmits the recorded temperature and weight time-series data and the electronic reference identifier to a mobile electronic device, which in this example may be a smartphone or a laptop. The mobile electronic device then transmits the recorded temperature and weight time-series data over the internet to a remote computing device, which in this example is a server. The computing device includes a processor and memory including computer program code. The memory and computer program code are configured to, with the processor, enable the computing device to carry out various processing functions.

As detailed above, the recorded temperature time-series data tracks the pyrolysis temperatures and the loading of biomass from the bottom up over the duration of the biochar production process, while the recorded weight time-series data tracks the loading of biomass into the trough 40 and the pyrolysis of the biomass over the duration of the biochar production process. As a result, the computing device is able to process the recorded temperature and weight time-series data to generate the characterisation profile of the biochar production process. The distinctly different patterns of temperature data captured by each of the two thermocouples 34 provides vital information on the manner of operation and the attainment of the high temperatures of the biochar production process in order to assess biochar carbon long-term stability, especially when correlated with the changing pattern of biomass weight as biomass is loaded and simultaneously being pyrolysed. This is illustrated by the characterisation profiles of Figures 13 to 15 that are generated from temperature and weight time-series data from different biochar production processes. It was observed by the inventors that the biochar production process is characterised by a reduction in temperature 96 measured by the lower thermocouple 34 alongside an increase in temperature 98 measured by the higher thermocouple 34 towards the end of the biochar production process, as shown in Figures 13 and 14. Furthermore, Figure 15 shows that the biomass weight addition and the biomass weight reduction can be collated 106 to determine the total biomass weight addition and the total biomass weight reduction as a way of characterising the biochar production process.

A distributed network of multiple biomass pyrolysis apparatus 30 in different sites may be provided. In such a distributed network, the recorded temperature and weight time-series data from each biomass pyrolysis apparatus 30 is transmitted to a central computing device that then processes the temperature and weight time-series data to generate a respective characterisation profile of the biochar production process carried out by each of the multiple biomass pyrolysis apparatus 30. Verification of the recorded temperature and weight time-series data can be performed using the unique electronic reference identifier provided by each data capture device 38. The recorded temperature and weight time-series data preferably includes date and time-of-day stamp data. Therefore, the central computing device can automatically monitor every biochar production process by each biomass pyrolysis apparatus 30 to collect and aggregate biochar production data from the multiple, uniquely identifiable biomass pyrolysis apparatus 30. The generation of the characterisation profiles enable analysis of the biochar production process carried out by each of the multiple biomass pyrolysis apparatus 30 in order to assess biochar production performance and identify potential improvements that are unique to each of the multiple biomass pyrolysis apparatus 30.

The distributed network of multiple biomass pyrolysis apparatus 30 in accordance with the invention enables worldwide production of biochar with high quality control and verification mechanisms in place to realise its potential as a globally significant carbon removal mechanism and environmental sustainability improver. The aggregation of multiple datasets not only helps to overcome local quality assurance limitations whilst meeting the stringent validation requirements of carbon capture methodologies but also provides a statistically robust source of performance data to permit the certification of carbon credits. Moreover, the distributed network of multiple biomass pyrolysis apparatus 30 in accordance with the invention empowers smallholders and smaller commercial operators (or larger operators with remote operations) worldwide to contribute to, and benefit from, the atmospheric carbon dioxide removals derivable from biochar generation and its many applications.

The invention is applicable to other types of biochar kilns, such as a retort kiln or larger commercial biochar kilns.

The listing or discussion of an apparently prior published document or apparently prior published information in this specification should not necessarily be taken as an acknowledgement that the document or information is part of the state of the art or is common general knowledge.

Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.

Claims

CLAIMS1. A biomass pyrolysis apparatus for carrying out a biochar production process, the biomass pyrolysis apparatus comprising: a biochar kiln; at least one temperature sensor configured to, in use, measure a temperature inside the biochar kiln; at least one weight sensor operably coupled to the biochar kiln so that the or each weight sensor is configured to, in use, measure a change in weight of biomass inside the biochar kiln; and a data capture device configured to, in use, record temperature data obtained by the or each temperature sensor and weight data obtained by the or each weight sensor.
2. A biomass pyrolysis apparatus according to Claim 1 wherein the temperature data includes temperature time-series data.
3. A biomass pyrolysis apparatus according to any one of the preceding claims wherein the or each temperature sensor is operably coupled to the biochar kiln so that the or each temperature sensor is configured to, in use, measure a temperature inside the biochar kiln.
4. A biomass pyrolysis apparatus according to any one of the preceding claims including first and second temperature sensors, wherein the first and second temperature sensors are configured to, in use, measure temperatures at different heights inside the biochar kiln.
5. A biomass pyrolysis apparatus according to Claim 4 wherein the data capture device is configured to, in use, start recording the temperature data obtained by the or each temperature sensor and the weight data obtained by the or each weight sensor when the lower of the first and second temperature sensors detects a predefined temperature above ambient temperature and/or stop recording the temperature data obtained by the or each temperature sensor and the weight data obtained by the or each weight sensor when, or following a pre-determined period of time after, the lower of the first and second temperature sensors detects a second predefined temperature above ambient temperature.
6. A biomass pyrolysis apparatus according to any one of the preceding claims wherein the weight data includes weight time-series data.
7. A biomass pyrolysis apparatus according to any one of the preceding claims including a plurality of weight sensors operably coupled to different points of the biochar kiln so that the plurality of weight sensors is configured to, in use, measure a change in weight of biomass inside the biochar kiln.
8. A biomass pyrolysis apparatus according to any one of the preceding claims wherein the data capture device includes a wireless transmitter for transmitting the recorded temperature and weight data.
9. A biomass pyrolysis apparatus according to Claim 8 wherein the data capture device includes a switch operable to selectively turn the wireless transmitter on and off.
10. A biomass pyrolysis apparatus according to Claim 9 including a magnetic device configured for magnetically operating the switch to selectively turn the wireless transmitter on and off.
11. A biomass pyrolysis apparatus according to any one of the preceding claims wherein the data capture device includes an electronic reference identifier for identifying the biomass pyrolysis apparatus.
12. A biomass pyrolysis apparatus according to any one of the preceding claims wherein the biochar kiln is a flame curtain kiln or a retort kiln.
13. A biochar kiln comprising a trough and a heat shield wall, wherein the trough is shaped as a quadrilateral frustum, wherein the heat shield wall is suspended from walls of the trough so that the heat shield wall surrounds the trough.
14. A biochar kiln according to Claim 13 wherein the heat shield wall includes at least one overhang section that is arranged inwards towards the trough, wherein the or each overhang section is positioned above the trough.
15. A biochar kiln according to Claim 13 or Claim 14 including a plurality of reinforcement members, wherein the reinforcement members are attached along the walls of the trough so as to reinforce the walls of the trough, wherein each reinforcement member is attached or coupled to the heat shield wall.
16. A biomass pyrolysis apparatus according to any one of Claims 1 to 12 wherein the biochar kiln is in accordance with any one of Claims 13 to 15.
17. A biomass pyrolysis system comprising a biomass pyrolysis apparatus in accordance with any one of Claims 1 to 12 and 16, the biomass pyrolysis system including a processor, the biomass pyrolysis system configurable so that the processor receives the recorded temperature and weight data from the data capture device of the biomass pyrolysis apparatus, wherein the processor is programmed to process the recorded temperature and weight data to generate a characterisation profile of the biochar production process.
18. A biomass pyrolysis system according to Claim 17 including a plurality of biomass pyrolysis apparatus, each biomass pyrolysis apparatus in accordance with any one of Claims 1 to 12 and 16, the biomass pyrolysis system configurable so that the processor receives the recorded temperature and weight data from the data capture device of each of the plurality of biomass pyrolysis apparatus, wherein the processor is programmed to process the recorded temperature and weight data to generate a respective characterisation profile of the biochar production process carried out by each of the plurality of biomass pyrolysis apparatus.
19. A biomass pyrolysis system according to Claim 17 or Claim 18 wherein the biomass pyrolysis system is configurable so that the processor receives the recorded temperature and weight data from the or each data capture device via a telecommunications network.
20. A method of characterising a biochar production process carried out by a biomass pyrolysis apparatus, the biomass pyrolysis apparatus comprising: a biochar kiln; at least one temperature sensor configured to, in use, measure a temperature inside the biochar kiln; and at least one weight sensor operably coupled to the biochar kiln so that the or each weight sensor is configured to, in use, measure a change in weight of biomass inside the biochar kiln, wherein the method comprises the step of recording temperature data obtained by the or each temperature sensor and weight data obtained by the or each weight sensor.
21. A method according to Claim 20 including the step of processing the recorded temperature and weight data to generate a characterisation profile of the biochar production process.
22. A method according to Claim 21 wherein the biomass pyrolysis apparatus includes first and second temperature sensors, wherein the first and second temperature sensors are configured to, in use, measure temperatures at different heights inside the biochar kiln, wherein the characterisation profile includes a decrease in temperature measured by the lower temperature sensor and an increase in temperature measured by the upper temperature sensor towards an end of the biochar production process.
23. A method according to Claim 21 or 22 wherein the characterisation profile includes variations in biomass weight that indicate addition and reduction of biomass from the biochar kiln at different points of the biochar production process.
24. A method of characterising a plurality of biochar production processes respectively carried out by a plurality of biomass pyrolysis apparatus, the method comprising the steps of carrying out the method of any one of Claims 20 to 23 in respect of each biomass pyrolysis apparatus, wherein the method includes the step of obtaining the recorded temperature and weight data of each of the plurality of biomass pyrolysis apparatus via a telecommunications network.
25. A method according to Claim 24 including the step of obtaining the recorded temperature and weight data and an electronic reference identifier of each of the plurality of biomass pyrolysis apparatus via the telecommunications network, wherein each of the plurality of biomass pyrolysis apparatus is associated with a respective unique electronic reference identifier.