Cooling system for hot biocoal

Abstract

An apparatus for cooling pyrolysis coal, the apparatus comprising: - a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and - a spraying device configured to disperse water; wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

Description

TECHNICAL FIELD

[0001] The present disclosure is directed generally to the field of pyrolysis coal handling apparatuses.BACKGROUND OF THE INVENTION:

[0002] As the demand for sustainable and renewable energy sources continues to grow, biocoal, a solid fuel derived from biomass through pyrolysis, has emerged as a promising alternative to traditional coal in various industrial applications. Biocoal offers several advantages, including a lower carbon footprint and the potential to utilize waste materials. The utilization of biocoal in energy production, but also for carburizing iron in steel production and for gasification presents unique challenges in terms of efficient and reliable material handling. For example, existing conveyor systems, designed primarily for conventional coal, may face limitations when tasked with conveying hot biocoal due to differences in material characteristics and processing requirements. One significant challenge in the production and handling of biocoal is managing its high temperatures post-production.

[0003] During the production process, biocoal can reach extremely high temperatures, often exceeding 300°C. This residual heat poses several issues, including the risk of spontaneous combustion, degradation of material quality, and safety hazards for handling and storage. Effective cooling mechanisms are, therefore, critical to mitigate these risks and ensure the safe and efficient use of biocoal. In response to the need for innovative solutions tailored to the distinct properties of hot biocoal, the present invention introduces a dedicated cooling system. This system is designed to efficiently and reliably prepare hot biocoal for subsequent handling in industrial settings, addressing the challenges posed by its combustibility, the abrasive nature, variable particle sizes, and elevated temperatures associated with this renewable fuel.

[0004] Conventional coal handling systems have been widely employed for material handling in various industries, including coal transportation. However, existing handling technologies are often optimized for handling materials with specific characteristics, and their adaptability to hot biocoal may be limited. The prior art lacks specialized handling systems explicitly designed for the unique challenges posed by treating hot biocoal.

[0005] For example, pneumatic conveyor systems have been used in industrial applications for their flexibility and ability to handle abrasive materials. The specific demands of conveying hot biocoal have not been comprehensively addressed in the prior art. Existing solutions may not adequately consider factors such as temperature control, minimizing material degradation, and optimizing energy efficiency in the context of conveying hot biocoal.

[0006] Within the framework of this application, hot coal or hot biocoal is coal or biocoal having a temperature above its ignition temperature.

[0007] WO 2021 / 018794 describes a torrefaction method comprising forwarding biomass through a process chamber; heating the biomass in the process chamber to a predetermined temperature and pyrolyzing the biomass to release syngas from the biomass, wherein the syngas contains at least 20% of the power contained in the flow of the biomass; and oxidizing the syngas to heat the biomass in the process chamber.

[0008] EP 3 771 739 A1 describes an apparatus for handling hot coal, comprising a cooling structure arranged to receive coal from a process chamber and to cool the coal in an atmosphere impeding ignition; and a pneumatic conveyor system arranged to move coal by air pressure. The cooling structure is configured to cool the coal to a surface temperature allowing the pneumatic conveyor system to convey the coal across a predetermined distance without the coal igniting.SUMMARY

[0009] While the invention is defined in the independent claims, further aspects of the invention are set forth in the dependent claims, the drawings and the following description.BRIEF DESCRIPTION OF THE FIGURES

[0010] These and other aspects will now be described with reference to the following drawing in which: Fig. 1 is a schematic illustration showing a processing apparatus according to an embodiment of the invention.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Fig. 1 shows a handling apparatus for coal comprising a cooling structure 10, a pneumatic conveyor system 20 and a bulk storage 30. Before explaining the handling apparatus in detail, some general aspects of the invention will be discussed.

[0012] According to an aspect, an apparatus for cooling pyrolysis coal is provided, the apparatus comprising: a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and a spraying device configured to disperse water; wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

[0013] An objective of the present invention is to cool pyrolysis coal to a temperature safe for handling. In this context, pyrolysis coal is a carbon material derived from biomass through pyrolysis, such as biocoal or charcoal. In various embodiments the carbon material is derived from biomass in a torrefaction process. The invention aims to overcome the limitations of existing technologies by introducing a dedicated approach to cool pyrolysis coal that considers the unique characteristics and challenges associated with hot pyrolysis coal particularly produced in torrefaction.

[0014] Objectives of the invention may include safe handling, optimizing energy efficiency, minimizing material degradation, and / or ensuring temperature control. By addressing these objectives, the invention contributes to the advancement of material handling technologies in the growing field of sustainable energy production, facilitating the integration of pyrolysis coal into industrial processes with improved efficiency and environmental sustainability.

[0015] The inventors have realized that pyrolysis coal exiting a pyrolysis reactor is exothermal and may continue heating itself unless its temperature drops below a threshold temperature. In various embodiments the threshold temperature is between 270 °C and 290 °C, preferably 280 °C. The pyrolysis coal above the threshold temperature typically is exothermal due to exothermic thermal decomposition, wherein chemical bonds breaking down to form new bonds while releasing volatile gases such as hydrogen, carbon monoxide and various hydrocarbons, and / or wherein rearrangements of carbon molecules into more stable char configurations (carbonization). Both types of thermal decomposition reactions may also take place when oxygen is essentially absent.

[0016] While water is usually an effective coolant, the required amount of water as primary coolant is high, significantly increases the water content of the resulting pyrolysis coal and the generated steam is difficult to clean from dust particles picked up from the pyrolysis coal. The generated steam thus is difficult to use for energy recuperation, such that a significant part of the thermal energy form the pyrolysis coal is lost. Water cooling of pyrolysis coal implies that essentially all the water used for cooling changes to steam.

[0017] Dry cooling of the pyrolysis coal is less effective than water and it was found that it is not always sufficiently effective. Particularly, when pyrolysis coal is above the threshold temperature, the energy released as heat may exceed the energy removed by the dry cooling of the pyrolysis coal. This may render the dry cooling essentially ineffective. That is, the pyrolysis coal keeps heating up despite the dry cooling. Without being bound by theory, it is believed that variations in the size and composition of the pyrolysis coal cause some particles to remain exothermal and to not cool down sufficiently. Insufficiently cooled pyrolysis coal particles ignite once contacting air prior to reaching the safe atmosphere. Once one pyrolysis coal particle ignites, the released heat ignites adjacent pyrolysis coal particles, igniting further adjacent pyrolysis coal particles in turn. This is only stopped once all ignited coal particles reach the safe atmosphere or any resupply is shut off so that no new pyrolysis coal particles reach the ignited pyrolysis coal particles.

[0018] The inventors have realized that applying a reduced amount of water at the pyrolysis coal may be enough to drop the temperature of the pyrolysis coal below the threshold temperature. The pyrolysis coal below the threshold temperature stops being exothermal and the dry cooling can effectively cool the pyrolysis coal. Once the pyrolysis coal is below the threshold temperature, the pyrolysis coal does not heat itself. The dry cooling more reliably cools the pyrolysis coal to below its ignition temperature.

[0019] The water enters the cooling structure and changes to steam particularly when contacting the hot pyrolysis coal. In various embodiments all the dispersed water evaporates. Due to the phase change of the water from the liquid phase to the gas phase sufficient thermal energy is removed from the pyrolysis coal. The dispersed water not only aids in cooling by evaporation but also helps in dust control and passivation of the gas surrounding the pyrolysis coal by generating steam. This works as follows: many types of torrefaction and pyrolysis reactors operate with pressure below atmospheric pressure created by a fan. As a result the outfeed end draws / sucks in gas to fulfil the mass balance requirement. To make sure that essentially no oxygen is present in that gas, nitrogen is supplied. Nitrogen is costly. When the present method of water evaporation is provided, the nitrogen can substantially be replaced by the steam that is generated which in turn contributes to the balancing of the mass required by the fan that creates the pressure below atmospheric pressure. This also reduces the risk of dust explosions. The dispersed water takes out dust of pyrolysis coal. In various embodiments the dust of pyrolysis coal agglutinates to form larger pyrolysis coal particles. This reduces the surface area to contact air and to receive thermal radiation from other pyrolysis coal particles. The water and / or steam also sometimes passivates the pyrolysis coal by displacing air or oxygen in the surroundings of the pyrolysis coal after release from the cooling structure. In contrast to conventional water cooling, according to the invention the amount of water applied to the hot pyrolysis coal is so low that it can remain with the pyrolysis coal and does not need to be discharged separately. In various embodiments the spraying device is configured to supply an amount of water that is essentially evaporated when the pyrolysis coal has passed from the coal inlet until half the distance to the coal outlet.

[0020] In various embodiments the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in the first half, preferably in the first third, more preferably in the first quarter, more preferably in the first tenth, of the path from the coal inlet to the coal outlet. In the following, the coal inlet is also referred to as cooling inlet. In the following, the coal outlet is also referred to as cooling outlet.

[0021] In various embodiments dry cooling applies heat dissipation for removing thermal energy from the pyrolysis coal, the heat dissipation being selected from the group consisting of a solid cooling structure and a cooling gas, the solid structure preferably comprising an inner wall of the cooling structure.

[0022] That is, dry cooling means cooling without water in the liquid phase contacting the pyrolysis coal. In various embodiments, the cooling structure comprises a vessel to accommodate the pyrolysis coal. In various embodiments with the heat dissipation being the solid cooling structure, the cooling structure comprises the vessel and a shell enclosing the vessel and being spaced apart from the vessel so as to provide a flow path for a cooling fluid between the vessel and the shell. The inner wall of the vessel thus forms the inner wall of the cooling structure and is configured to apply heat dissipation as claimed. The inner wall is configured to transfer the thermal energy from the pyrolysis coal to the cooling fluid. In various embodiments, the cooling fluid is a liquid such as water, glycol, molten salt or mineral oil. In various embodiments the cooling fluid is a gas, such as an inert gas such as nitrogen, argon or sulfur hexafluoride. As the cooling fluid does not contact the pyrolysis coal, the cooling fluid can be recirculated with limited recycling and cleaning, if at all.

[0023] In various embodiments with the heat dissipation being the cooling gas, the cooling gas is within the cooling structure and directly contacts the pyrolysis coal. In various embodiments the cooling gas is an inert gas such as nitrogen, argon or sulfur hexafluoride. As the cooling gas does not undergo a phase change with the implied sudden expansion, the cooling gas does not raise as much dust as the water cooling. The cooling gas thus can be recirculated with limited recycling and cleaning.

[0024] Dry cooling often does not release as much dust as water cooling, as there is no phase change from liquid to gas with the implied sudden expansion of volume of the water. Accordingly, for embodiments with the heat dissipation being a solid cooling structure, the dust remains essentially with the pyrolysis coal, such that this dry cooling maintains the energy content of the pyrolysis coal.

[0025] In the present context, pyrolysis coal mostly having a temperature above its ignition temperature means that the amount of pyrolysis coal having a temperature above the ignition temperature is larger than the amount of pyrolysis coal having a temperature below the ignition temperature. Unless specified differently herein, the term "water" means water in the liquid phase, and the term "steam" means water in the gas phase.

[0026] In various embodiments, the apparatus further comprises a pneumatic conveyor system configured to receive the pyrolysis coal from the cooling structure and to move pyrolysis coal by means of an airflow; and a gaslock arranged to allow pyrolysis coal to pass from the cooling structure into the pneumatic conveyor system and to impede communicating fluid exchange between the cooling structure and the pneumatic conveyor system, the gaslock preferably being a rotary gaslock.

[0027] In various embodiments a further objective of the present invention is to provide a pneumatic conveyor system with improved transportation safety of hot pyrolysis coal and / or enhancing the overall reliability of the pneumatic conveyor system for hot pyrolysis coal. Previously it was found that hot pyrolysis coal particles can be conveyed by means of a pneumatic conveyor if they are cooled enough so that its surface temperature is below an ignition temperature. If the distance along which the coal is conveyed is sufficiently short and the coal is thereafter received in a safe atmosphere that impedes ignition, the risk of pyrolysis coal igniting during pneumatic conveying is substantially reduced. A typical safe atmosphere that impedes ignition may be a container filled with inert gas.

[0028] Even though pneumatic conveyors with hot pyrolysis coal work mostly well and safe, there remains a risk that some of the pyrolysis coal particles ignite in the pneumatic conveyor. As the ignited coal particles are usually received in an inert atmosphere, they stop burning, and safe handling and storing of the coal particles is still possible. However, such occasional ignition is not only a safety hazard, it also reduces the energy content of the processed pyrolysis coal and thus, the efficiency of the production of biocoal from biomass. In various embodiments, the pneumatic conveyor system's design considers factors such as temperature control, minimizing material degradation, and optimizing energy efficiency of the resulting pyrolysis coal, which are essential when conveying hot pyrolysis coal.

[0029] In various embodiments the apparatus further comprises a gaslock arranged to allow coal to pass from the cooling structure into the pneumatic conveyor system and to impede communicating fluid exchange between the cooling structure and the pneumatic conveyor system, the gaslock preferably being a rotary gaslock. Such a rotary gaslock is usually arranged much like a revolving door, that is with at least three panels arranged on a common rotary shaft and at least two panels at any point in time sealing against opposite inside walls of cylinder sections such that fluid communication through the airlock is permanently prevented or reduced. Other types of gaslocks can also be used. For example, a sliding gate valve or a double-flap valve could be employed to achieve the same function of allowing pyrolysis coal transfer while impeding fluid exchange between the cooling structure and the pneumatic conveyor system.

[0030] In various embodiments the spraying device is configured to disperse the water as a mist. Such a water mist has a comparably large surface area per volume and thus evaporates in the vicinity of the pyrolysis coal particularly effectively.

[0031] In various embodiments the spraying device comprises a spray nozzle spraying in a direction transversal to the conveying direction of the coal. This configuration exposes most coal to the evaporative of the sprayed water and cools the coal effectively.

[0032] In various embodiments the spraying device is configured to disperse water in a flat fan pattern extending transversal to a conveying direction of the coal. Spraying the water in a flat fan pattern extends a wetted portion across an extended part of a cross section of the conveyed coal. Such pattern can be achieved by selecting a corresponding spray nozzle and / or by arranging a series of spray nozzles in a corresponding pattern. In various embodiments, the spraying device comprises a pressure regulation mechanism. This pressure regulation mechanism allows for control over the water pressure, which affects the size and intensity of the mist as well as the overall flow expressed in liter per hour.

[0033] In various embodiments the spraying device is configured to disperse water in a conical pattern spraying in a direction transversal to a conveying direction of the coal.

[0034] In various embodiments the spraying device is configured to adjust a flow rate, a droplet size in the mist and / or a pattern of the dispersed water. In various embodiments, the spraying device may utilize different mechanisms to disperse water as a mist. For example, instead of using a nozzle-based system, the apparatus may employ ultrasonic technology to create the mist. Ultrasonic misting devices utilize high-frequency vibrations to break down water into droplets, resulting in a mist-like spray. Other embodiments may involve the use of a rotating disc or drum within the spraying device. This rotating component has a perforation or opening that allows water to be expelled as a mist when the disc or drum spins.

[0035] In various embodiments the spraying device is configured to increase a water content of the pyrolysis coal by less than 3%-points, preferably by less than 2%-points. For example, when the pyrolysis coal has a water content of 2% when entering the cooling structure, the spraying device increases the water content to a total amount of less than 5%, preferably less than 4%.The inventors have realized that this amount of water is enough to sufficiently reduce the temperature of the pyrolysis coal so that exothermal reactions are not continuing heating the pyrolysis coal while undergoing dry cooling. In various embodiments the spraying device is configured to disperse 20-50 l of water per hour per 1-1.5 metric ton of pyrolysis coal per hour. In various embodiments, the spraying device is configured to disperse 30 litres of water per ton of pyrolysis coal per hour.

[0036] In various embodiments the cooling structure is configured to cool the pyrolysis coal to a surface temperature below its ignition temperature.

[0037] In various embodiments the spraying device comprises a control unit including a microprocessor and a memory, the memory comprising instructions which, when executed by the microprocessor, cause the microprocessor to control the of any preceding embodiment, particularly to control the cooling structure, the pneumatic conveyor system and / or the spraying device. In various embodiments, the control unit, the microprocessor and the memory a digital circuits processing a computer program particularly written in a formal language. In further embodiments, the control unit, the microprocessor and the memory are configured as analogue circuitry implicitly storing the instructions.

[0038] In various embodiments the instructions for controlling the cooling structure comprise instructions for detecting a temperature of the pyrolysis coal and for adjusting a cooling action depending on the temperature. Adjusting the cooling action according to a detected temperature allows economizing the cooling action while allowing for extended operation times of the cooling structure.

[0039] In various embodiments the cooling structure comprises a conveyor to move the pyrolysis coal towards the coal outlet and the instructions for controlling the cooling structure comprise instructions for adjusting the movement of the conveyor depending on the temperature of the pyrolysis coal. In various embodiments the conveyor is a conveying screw moving the pyrolysis coal through the vessel of the cooling structure. In various embodiments the instructions for controlling the cooling structure comprise instructions for the conveyor to move the pyrolysis coal faster to the coal outlet, if the temperature of the pyrolysis coal is sufficiently low, and to move the pyrolysis coal slower to the coal outlet, if the temperature of the pyrolysis coal is too higher for being released earlier.

[0040] In various embodiments the instructions for controlling the pneumatic conveyor system comprise instructions for detecting an airflow velocity and / or an airflow temperature, and for adjusting at the pneumatic conveyor, the airflow velocity and / or a throughput of the coal. An increased airflow velocity at a given coal input reduces the amount of conveyed coal in a given section of the pneumatic conveyor system and thus reduces the number of coal particles that can ignite. Likewise reducing a throughput of coal reduces the number of coal particles that can ignite in a given section of the pneumatic conveyor system.

[0041] In various embodiments the instructions for controlling the spraying device comprise instructions for detecting a temperature of the coal and for adjusting water dispersing at the spraying device. If the coal temperature is below a threshold temperature, water dispersing can be reduced such that water can be saved and less water needs to dry off from the coal.

[0042] In various embodiments the apparatus further comprises a temperature sensor configured to detect a temperature of the coal inside the pneumatic conveyor and to indicate the temperature to the microprocessor, the temperature sensor preferably being sensitive to electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm.

[0043] In various embodiments the temperature sensor is arranged in a conveying direction of the coal prior to the spraying device, and the spraying device is configured to selectively spray the coal when the temperature sensor detects that the coal passes a temperature threshold.

[0044] In various embodiments the apparatus further comprises a torrefaction installation configured to provide pyrolysis coal into the cooling structure.

[0045] According to another aspect, a method for handling pyrolysis coal is provided, the method comprising: receiving pyrolysis coal mostly having a temperature above its ignition temperature; after receiving the pyrolysis coal, dispersing water at the pyrolysis coal; and after dispersing water, dry cooling the pyrolysis coal in an atmosphere impeding ignition.

[0046] An atmosphere impeding ignition particularly is an atmosphere having no oxygen. Dry cooling according to this aspect thus takes place in the absence of oxygen.

[0047] In various embodiments, the pyrolysis coal is received at a temperature to react exothermally. After dispersing water, the pyrolysis coal does not react exothermally.

[0048] Coming back to Fig. 1 the cooling structure according to the depicted embodiment is arranged to receive coal from a process chamber 1. In various embodiments the process chamber 1 is arranged to generally increase carbon density of organic- or fossil fuel-based carbonaceous materials. To that end a number of techniques are known, usually they include heat exposure of the carbonaceous material. In various embodiments the carbonaceous material undergoes a pyrolysis process. In some embodiments the carbonaceous material undergoes a torrefaction process such as the one described in WO 2015 / 084162 A1. In various embodiments the carbonaceous material enters the process chamber 1 as biomass, such as wood, bark, leaves or grass.

[0049] Once the carbonaceous material is turned into a predetermined grade of coal, that is, the carbonaceous material has the predetermined mass energy density, the coal usually has a temperature above its ignition temperature. Thus, before exposing the coal to air, it needs to be cooled. In the embodiment, the carbonaceous material is biomass such that the resulting coal will be referred to as pyrolysis coal in the following. The pyrolysis coal thus passes from the process chamber 1 to the cooling structure 10. In the cooling structure 10 the pyrolysis coal is cooled such that torrefaction is stopped and the pyrolysis coal has consistent characteristics once exiting the cooling chamber 10. In various embodiments the cooling structure 10 comprises a dry cooling element promoting a temperature decrease of the pyrolysis coal. In various embodiments the dry cooling element comprises a cooling liquid circulation structure for water or an oil based coolant (thermo oil). In various embodiments the dry cooling element comprises at least one channel allowing circulation of a cooling fluid adjacent to an inner surface of the cooling structure 10.

[0050] In various embodiments the interior of the process chamber 1 and at least a part of the interior of the cooling structure 10 are in fluid communication. In various embodiments the cooling structure 10 comprises a cooling chamber 11. In various embodiments the pyrolysis coal passes from the process chamber 1 to the cooling chamber 11.In various embodiments, the cooling chamber 11 comprises a cooling inlet 11a and a cooling outlet 11b. In various embodiments the dry cooling element forms a portion of the cooling chamber 11, the cooling chamber preferably forming an inner wall comprising the at least one channel allowing circulation of the cooling fluid adjacent to an inner surface of the cooling chamber 11. The inner wall comprises an inner surface for interfacing with the pyrolysis coal.

[0051] In various embodiments the process chamber 1 and the cooling chamber 11 are in fluid communication. Alternatively, the cooling chamber 11 comprises a gaslock at the cooling inlet 11a, such that fluid exchange between the process chamber 1 and the cooling chamber 11 is prevented and the pyrolysis coal passes from the process chamber 1 to the cooling chamber 11 through the gaslock. The gaslock is configured to allow the pyrolysis coal to pass while preventing gas exchange between the process chamber 1 and the cooling chamber 11.

[0052] In various embodiments the cooling chamber 11 comprises a conveying element 15. In some embodiments, the cooling chamber 11 comprises a conveying element 15 arranged to convey the pyrolysis coal from the cooling inlet 11a of the cooling chamber 11 to the cooling outlet 11b of the cooling chamber 11. In various embodiments the conveying element is a conveying screw 15 or a chain conveyor. In various embodiments the conveying screw 15 in the cooling chamber 11 is configured to continuously move and mix the pyrolysis coal such that different portions of the pyrolysis coal are in contact with the inner surface of the cooling chamber 11. Where the inner surface is cooled, particularly by the dry cooling element, the pyrolysis coal dissipates heat and cools down. In some embodiments the screw 15 has a shaft containing a passage for cooling fluid circulation. While only depicted to extend through a portion of the cooling chamber 11 in Fig. 1, in various embodiments the conveying element 15 extends from the cooling inlet 11a to the cooling outlet 11b.

[0053] In various embodiments the cooling chamber 11 comprises a purging arrangement dispensing an inert gas into the cooling chamber 11. The inert gas reduces oxygen exposure and impedes that the pyrolysis coal ignites. The inert gas cools down the pyrolysis coal in the cooling chamber 11. In various embodiments the inert gas is nitrogen or carbon dioxide.

[0054] In various embodiments the cooling structure 10 comprises a spraying device 14 configured to dispense water into the cooling chamber 11. The spraying device 14 is arranged in proximity to the cooling inlet 11a. The inventors have realized that the pyrolysis coal coming from the process chamber 1 has a temperature in a range that the pyrolysis coal can continue an exothermic reaction even inside the cooling chamber 11. That is, due to the exothermic reaction the pyrolysis coal continues to generate heat. In various embodiments the exothermic reaction generates more thermal power than the thermal power removed by the dry cooling element particularly constituted by the inner surface of the cooling chamber 11. The exothermic reaction thus may prevent the cooling of the pyrolysis coal. The inventors have further realized that spraying water on the pyrolysis coal effects a steep temperature drop such that the exothermic reaction is reduced or terminated.

[0055] In various embodiments the spraying device 14 is configured to disperse at least enough water that the combined cooling by the sprayed water and the dry cooling element reduces the temperature of the pyrolysis coal. In various embodiments the spraying device 14 is configured to disperse the water as a mist. The water mist effectively absorbs the heat from the pyrolysis coal, causing rapid evaporation and cooling. This process helps bringing the surface temperature of the pyrolysis coal below its ignition temperature. In various embodiments the spraying device 14 comprises a spray nozzle. In various embodiments the spray nozzle is configured to disperse water in a conical pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal. In various embodiments the spray nozzle is configured to disperse water in a flat fan pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal and extending transversal to a conveying direction of the conveying element 15. In various embodiments the spraying device 14 comprises a water supply such as a water tank and / or a connection to a public water source. In various embodiments the spraying device 14 comprises a pressurizing member, such as a water pump, configured to force water from the water supply through the spray nozzle into the cooling chamber 11.

[0056] In various embodiments the cooling structure 10 comprises at least two cooling chambers each cooling chamber configured to receive the pyrolysis coal from the process chamber 1 and / or from a preceding cooling chamber. In various embodiments each cooling chamber comprises a cooling inlet and a cooling outlet. In various embodiments each cooling inlet comprises a gaslock. Each gaslock is configured to allow the pyrolysis coal to pass while preventing gas exchange with the cooling chambers. The cooling chambers essentially correspond to the cooling chamber 11 described in the previous and following paragraphs. In some embodiments the cooling chambers are configured to move the pyrolysis coal upslope to allow gravity feeding through the following gaslock. In various embodiments only the first cooling chamber is configured with a water spraying device.

[0057] In various embodiments the handling apparatus comprises a control structure 16 configured to control an operation of the process chamber 1, the cooling structure 10, the pneumatic conveyor system 20 and / or the bulk storage 30. In various embodiments the control structure 16 comprises a microprocessor 16a and a memory 16b. The memory 16b comprises instructions which, when executed by the microprocessor 16a, cause the microprocessor 16a to control the process chamber 1, the cooling structure 10, the pneumatic conveyor 20 and / or the bulk storage 30. In various embodiments the control structure 16 is configured to control the spraying device 14, the dry cooling element and / or the conveying element 15.

[0058] In various embodiments the pneumatic conveyor system 20 comprises an inlet chute 21, a conveying channel 22 and a fan 24. The pneumatic conveyor system 20 is arranged to create an airflow strong enough to carry at least parts of the pyrolysis coal across some distance through the conveying channel 22. In various embodiments the pneumatic conveyor system 20 is arranged to convey pyrolysis coal from the cooling structure 10 to the bulk storage 30.

[0059] The inlet chute 21 is arranged to receive the pyrolysis coal from the cooling structure 10 through the cooling outlet 11b. In various embodiments the cooling structure 10 comprises a gaslock 13. The gaslock 13 is arranged between the cooling chamber 11 and the inlet chute 21. In various embodiments the cooling outlet 11b is arranged above the inlet chute 21 such that gravity causes the pyrolysis coal to move from the cooling outlet 11b into the inlet chute 21. In various embodiments the gaslock 13 is arranged between the cooling outlet 11b and the inlet chute 21. The gaslock 13 is arranged to allow pyrolysis coal to pass from the cooling chamber 11 into the inlet chute 21 of the pneumatic conveyor system 20 and to impede communicating fluid exchange between the cooling chamber 11 and the pneumatic conveyor system 20 as well as ambient air.

[0060] In some embodiments the conveying element 15 is configured to move the pyrolysis coal upslope to allow gravity feeding through the gaslock 13 and into the inlet chute 21.

[0061] In various embodiments the inlet chute 21 has a top opening 21c to receive the pyrolysis coal, an airflow outlet 21b opening towards the conveying channel 22 and an airflow inlet 21a arranged opposite to the airflow outlet 21b and allowing ambient air to enter the inlet chute 21 and the conveying channel 22. Pyrolysis coal disposed in the inlet chute 21 is dragged with the airflow 25 and conveyed through the conveying channel 22 towards the fan 24. In various embodiments the fan 24 is configured to create an airflow 25 through the pneumatic conveyor system 20, particularly through the conveying channel 21. In various embodiments the fan 24 is configured to operate accounting for the time the surface temperature of the pyrolysis coal is below the ignition temperature of the pyrolysis coal once cooling is stopped. Please note that in the airflow 25 the pyrolysis coal also cools at least initially as long as the velocity of the airflow 25 is different from the velocity of the pyrolysis coal.

[0062] In various embodiments the control structure 16 is configured to control the gaslock 13, the fan 24, and / or the airflow 25. In various embodiments the pneumatic conveyor system 20 comprises a temperature sensor 28 configured to detect a temperature of the pyrolysis coal inside the conveying channel 22. In various embodiments the temperature sensor is configured to indicate the temperature to the control structure 16. In various embodiments, the temperature sensor is sensitive to electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm. In various embodiments, the temperature sensor is an infrared radiation sensor. In various embodiments the control structure 16 is configured to adjust operations of the fan 24, the airflow 25, and / or the spraying device 14 dependent on the indication of the temperature sensor 28.

[0063] In various embodiments the conveying channel 22 is arranged with a separator 23. The separator 23 is arranged to remove solid particles from the airflow 25 conveyed through the conveying channel 22. In various embodiments the separator 23 is arranged to remove solid particles from the airflow 25 without using a filter. In some embodiments the separator 23 comprises a cyclone separator operating through vortex separation and / or a baffle assembly. The separator 23 is arranged to guide the pyrolysis coal into the bulk storage 30 and to allow the airflow 25 to pass towards the fan 24. In various embodiments the conveying channel 22 is arranged with a filter 26 between the separator 23 and the fan 24. In various embodiments the fan 24 is configured to supply enough pressure drop to account for the length, diameter and structure of the conveying channel 22, for the pressure drop across the separator 23 and the filter 26.

[0064] In various embodiments the bulk storage 30 is arranged to further cool the pyrolysis coal after conveying. The bulk storage 30 stores the pyrolysis coal at least until the remaining heat is insufficient to ignite the pyrolysis coal. In various embodiments the bulk storage comprises a container vessel 32. In various embodiments the bulk storage contains an inert gas impeding air exposure of the pyrolysis coal. With too little air, the pyrolysis coal cannot ignite even if the temperature is high. The inert gas in the container vessel 32 provides a safe atmosphere. In various embodiments the container vessel 32 is filled with nitrogen.

[0065] In various embodiments, the pyrolysis coal thus is processed in the following way: Pyrolysis coal produced by some process involving pyrolytic cracking of carbonaceous materials passes from a process chamber 1 to the cooling structure 10. In various embodiments the pyrolysis coal passes through a gaslock into the cooling structure 10. In various embodiments the pyrolysis coal passes into the cooling chamber 11. In various embodiments the spraying device 14 dispenses water into the cooling chamber 11 and onto the pyrolysis coal in proximity to the cooling inlet 11a. In various embodiments the pyrolysis coal contacts the dry cooling element. In various embodiments the cooling chamber 11 comprises a purging structure purging the pyrolysis coal with an inert gas. The inert gas may impede ignition of the pyrolysis coal and / or cool the pyrolysis coal. In various embodiments the conveying element 15 forwards the pyrolysis coal through the cooling chamber 11. In various embodiments the conveying element 15 mixes the pyrolysis coal to expose different portions of the pyrolysis coal to the dry cooling element, particularly the cooled inner wall of the cooling chamber 11. The conveying element 15 supports cooling of the pyrolysis coal.

[0066] In various embodiments the spraying device 14 disperses the water as a mist. In various embodiments the spray nozzle of the spraying device 14 disperses water in a conical pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal. In various embodiments the spray nozzle of the spraying device 14 disperses water in a flat fan pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal and extending transversal to a conveying direction of the conveying element 15. In various embodiments the spraying device 14 receives water from a water tank and / or a public water source.

[0067] In various embodiments the cooling chamber 11 cools the surface of the pyrolysis coal to a temperature below an ignition temperature of the pyrolysis coal. In various embodiments the cooling chamber 11 cools the surface of the pyrolysis coal to a temperature of below 100 °C to stop torrefaction, preferably below 40 °C, more preferably below 20 °C. In various embodiments the residence time of the pyrolysis coal in the cooling chamber 11 is adjusted to control the resulting temperature of the pyrolysis coal. In various embodiments the pyrolysis coal passes from the cooling chamber 11 through the gaslock 13. In various embodiments the pyrolysis coal is gravity fed from the cooling outlet 11b of the cooling chamber 11 through the gaslock 13 and into the inlet chute 21. In some embodiments the conveying element 15 moves the pyrolysis coal upslope to allow gravity feeding through the gaslock 13 and into the inlet chute 21. In various embodiments the pyrolysis coal passes from the cooling chamber 11 to the pneumatic conveyor system 20.

[0068] In various embodiments the cooling chamber 11 is filled between 40% and 60% with pyrolysis coal. This allows for an earlier contact of the biocoal with the dry cooling element of the cooling chamber 11 than when the cooling chamber 11 is almost entirely filled.

[0069] In embodiments having at least two cooling chambers consecutive chambers have increased fill with the last cooling chamber preferably being filled more than 90% with pyrolysis coal. This maximizes residence time and cooling and thus occupancy rate of the last cooling chamber. In some embodiments the filling of the last cooling chamber also impedes air passing from the inlet chute 21 into a cooling chamber.

[0070] The pneumatic conveyor system 20 provides the airflow 25 from the airflow inlet 21a to the separator 23 and the fan 24 via the conveying channel 22. In various embodiments the pyrolysis coal is dropped from above into the airflow 25. As long as there is significant relative movement between the airflow 25 and the pyrolysis coal therein, the airflow 25 further cools the pyrolysis coal. The pyrolysis coal moves along the conveying channel 22 towards the separator 23. In the separator 23, the pyrolysis coal is removed from the airflow 25 such that the airflow passes towards the fan 24 and the pyrolysis coal passes to the bulk storage 30. The airflow within the conveying channel 22 aids in distributing the water evenly across the pyrolysis coal particles, improving thorough cooling.

[0071] In various embodiments the pyrolysis coal passes into the safe atmosphere of the container vessel 32. The pyrolysis coal remains in the container vessel 32 preferably until the remaining heat is insufficient to ignite the pyrolysis coal even in an atmosphere of ambient air. Once the pyrolysis coal is sufficiently cooled, the pyrolysis coal can be discharged to the outside of the container vessel 32. The cooled pyrolysis coal is allowed to contact ambient air for prolonged periods of time. In various embodiments the pyrolysis coal is discharged towards a transport means 35.

[0072] In various embodiments the control structure 16 controls the operation of the process chamber 1, the cooling structure 10, the pneumatic conveyor system 20 and / or the bulk storage 30. In various embodiments the microprocessor 16a controls the process chamber 1, the cooling structure 10, the pneumatic conveyor 20 and / or the bulk storage 30. In various embodiments the control structure 16 controls the spraying device 14 and / or the conveying element 15. In various embodiments the control structure 16 controls the gaslock 13, the fan 24, and / or the airflow 25. In various embodiments the temperature sensor 28 detects a temperature of the pyrolysis coal inside the conveying channel 22. In various embodiments the temperature sensor indicates the temperature to the control structure 16. In various embodiments, the temperature sensor detects electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm. In various embodiments the control structure 16 adjusts operations of the gaslock 13, the fan 24, the airflow 25, and / or the spraying device 14 dependent on the indication of the temperature sensor 28. In various embodiments, the control structure 16 adjusts the spraying device 14 to obtain a desired cooling rate and / or moisture content of the pyrolysis coal. In various embodiments the spraying device 14 is configured to increase a water content of the pyrolysis coal by less than 3%-points, preferably by less than 2%-points. It was found that with the spraying device being arranged close to the cooling inlet 11a and with the water dispersing taking place before most of the dry cooling takes place, only a small amount of water is sufficient to reduce the temperature of the pyrolysis coal and thus render dry cooling effective.

[0073] In various embodiments the pyrolysis coal is transferred to a power plant for energy or heat production. In further embodiments the pyrolysis coal is used to store carbon, to produce steel and / or to upgrade soil and / or to feed a gassifier.

[0074] While this description of the inventive process refers to some pyrolysis coal at specific process steps, please note that in various embodiments the handling apparatus is operated continuously such that pyrolysis coal is present at different stages of the handling apparatus at the same time. While this description primarily refers to pyrolysis coal, also different types of coal produced according to conventional processes may be handled in the apparatus according to the invention.

Examples

Embodiment Construction

[0011]Fig. 1 shows a handling apparatus for coal comprising a cooling structure 10, a pneumatic conveyor system 20 and a bulk storage 30. Before explaining the handling apparatus in detail, some general aspects of the invention will be discussed.

[0012]According to an aspect, an apparatus for cooling pyrolysis coal is provided, the apparatus comprising:

a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and a spraying device configured to disperse water;

wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

[0013]An objective of the present invention is to cool pyrolysis coal to a temperature safe f...

TECHNICAL FIELD

[0001] The present disclosure is directed generally to the field of pyrolysis coal handling apparatuses.BACKGROUND OF THE INVENTION:

[0002] As the demand for sustainable and renewable energy sources continues to grow, biocoal, a solid fuel derived from biomass through pyrolysis, has emerged as a promising alternative to traditional coal in various industrial applications. Biocoal offers several advantages, including a lower carbon footprint and the potential to utilize waste materials. The utilization of biocoal in energy production, but also for carburizing iron in steel production and for gasification presents unique challenges in terms of efficient and reliable material handling. For example, existing conveyor systems, designed primarily for conventional coal, may face limitations when tasked with conveying hot biocoal due to differences in material characteristics and processing requirements. One significant challenge in the production and handling of biocoal is managing its high temperatures post-production.

[0003] During the production process, biocoal can reach extremely high temperatures, often exceeding 300°C. This residual heat poses several issues, including the risk of spontaneous combustion, degradation of material quality, and safety hazards for handling and storage. Effective cooling mechanisms are, therefore, critical to mitigate these risks and ensure the safe and efficient use of biocoal. In response to the need for innovative solutions tailored to the distinct properties of hot biocoal, the present invention introduces a dedicated cooling system. This system is designed to efficiently and reliably prepare hot biocoal for subsequent handling in industrial settings, addressing the challenges posed by its combustibility, the abrasive nature, variable particle sizes, and elevated temperatures associated with this renewable fuel.

[0004] Conventional coal handling systems have been widely employed for material handling in various industries, including coal transportation. However, existing handling technologies are often optimized for handling materials with specific characteristics, and their adaptability to hot biocoal may be limited. The prior art lacks specialized handling systems explicitly designed for the unique challenges posed by treating hot biocoal.

[0005] For example, pneumatic conveyor systems have been used in industrial applications for their flexibility and ability to handle abrasive materials. The specific demands of conveying hot biocoal have not been comprehensively addressed in the prior art. Existing solutions may not adequately consider factors such as temperature control, minimizing material degradation, and optimizing energy efficiency in the context of conveying hot biocoal.

[0006] Within the framework of this application, hot coal or hot biocoal is coal or biocoal having a temperature above its ignition temperature.

[0007] WO 2021 / 018794 describes a torrefaction method comprising forwarding biomass through a process chamber; heating the biomass in the process chamber to a predetermined temperature and pyrolyzing the biomass to release syngas from the biomass, wherein the syngas contains at least 20% of the power contained in the flow of the biomass; and oxidizing the syngas to heat the biomass in the process chamber.

[0008] EP 3 771 739 A1 describes an apparatus for handling hot coal, comprising a cooling structure arranged to receive coal from a process chamber and to cool the coal in an atmosphere impeding ignition; and a pneumatic conveyor system arranged to move coal by air pressure. The cooling structure is configured to cool the coal to a surface temperature allowing the pneumatic conveyor system to convey the coal across a predetermined distance without the coal igniting.SUMMARY

[0009] While the invention is defined in the independent claims, further aspects of the invention are set forth in the dependent claims, the drawings and the following description.BRIEF DESCRIPTION OF THE FIGURES

[0010] These and other aspects will now be described with reference to the following drawing in which: Fig. 1 is a schematic illustration showing a processing apparatus according to an embodiment of the invention.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Fig. 1 shows a handling apparatus for coal comprising a cooling structure 10, a pneumatic conveyor system 20 and a bulk storage 30. Before explaining the handling apparatus in detail, some general aspects of the invention will be discussed.

[0012] According to an aspect, an apparatus for cooling pyrolysis coal is provided, the apparatus comprising: a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and a spraying device configured to disperse water; wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

[0013] An objective of the present invention is to cool pyrolysis coal to a temperature safe for handling. In this context, pyrolysis coal is a carbon material derived from biomass through pyrolysis, such as biocoal or charcoal. In various embodiments the carbon material is derived from biomass in a torrefaction process. The invention aims to overcome the limitations of existing technologies by introducing a dedicated approach to cool pyrolysis coal that considers the unique characteristics and challenges associated with hot pyrolysis coal particularly produced in torrefaction.

[0014] Objectives of the invention may include safe handling, optimizing energy efficiency, minimizing material degradation, and / or ensuring temperature control. By addressing these objectives, the invention contributes to the advancement of material handling technologies in the growing field of sustainable energy production, facilitating the integration of pyrolysis coal into industrial processes with improved efficiency and environmental sustainability.

[0015] The inventors have realized that pyrolysis coal exiting a pyrolysis reactor is exothermal and may continue heating itself unless its temperature drops below a threshold temperature. In various embodiments the threshold temperature is between 270 °C and 290 °C, preferably 280 °C. The pyrolysis coal above the threshold temperature typically is exothermal due to exothermic thermal decomposition, wherein chemical bonds breaking down to form new bonds while releasing volatile gases such as hydrogen, carbon monoxide and various hydrocarbons, and / or wherein rearrangements of carbon molecules into more stable char configurations (carbonization). Both types of thermal decomposition reactions may also take place when oxygen is essentially absent.

[0016] While water is usually an effective coolant, the required amount of water as primary coolant is high, significantly increases the water content of the resulting pyrolysis coal and the generated steam is difficult to clean from dust particles picked up from the pyrolysis coal. The generated steam thus is difficult to use for energy recuperation, such that a significant part of the thermal energy form the pyrolysis coal is lost. Water cooling of pyrolysis coal implies that essentially all the water used for cooling changes to steam.

[0017] Dry cooling of the pyrolysis coal is less effective than water and it was found that it is not always sufficiently effective. Particularly, when pyrolysis coal is above the threshold temperature, the energy released as heat may exceed the energy removed by the dry cooling of the pyrolysis coal. This may render the dry cooling essentially ineffective. That is, the pyrolysis coal keeps heating up despite the dry cooling. Without being bound by theory, it is believed that variations in the size and composition of the pyrolysis coal cause some particles to remain exothermal and to not cool down sufficiently. Insufficiently cooled pyrolysis coal particles ignite once contacting air prior to reaching the safe atmosphere. Once one pyrolysis coal particle ignites, the released heat ignites adjacent pyrolysis coal particles, igniting further adjacent pyrolysis coal particles in turn. This is only stopped once all ignited coal particles reach the safe atmosphere or any resupply is shut off so that no new pyrolysis coal particles reach the ignited pyrolysis coal particles.

[0018] The inventors have realized that applying a reduced amount of water at the pyrolysis coal may be enough to drop the temperature of the pyrolysis coal below the threshold temperature. The pyrolysis coal below the threshold temperature stops being exothermal and the dry cooling can effectively cool the pyrolysis coal. Once the pyrolysis coal is below the threshold temperature, the pyrolysis coal does not heat itself. The dry cooling more reliably cools the pyrolysis coal to below its ignition temperature.

[0019] The water enters the cooling structure and changes to steam particularly when contacting the hot pyrolysis coal. In various embodiments all the dispersed water evaporates. Due to the phase change of the water from the liquid phase to the gas phase sufficient thermal energy is removed from the pyrolysis coal. The dispersed water not only aids in cooling by evaporation but also helps in dust control and passivation of the gas surrounding the pyrolysis coal by generating steam. This works as follows: many types of torrefaction and pyrolysis reactors operate with pressure below atmospheric pressure created by a fan. As a result the outfeed end draws / sucks in gas to fulfil the mass balance requirement. To make sure that essentially no oxygen is present in that gas, nitrogen is supplied. Nitrogen is costly. When the present method of water evaporation is provided, the nitrogen can substantially be replaced by the steam that is generated which in turn contributes to the balancing of the mass required by the fan that creates the pressure below atmospheric pressure. This also reduces the risk of dust explosions. The dispersed water takes out dust of pyrolysis coal. In various embodiments the dust of pyrolysis coal agglutinates to form larger pyrolysis coal particles. This reduces the surface area to contact air and to receive thermal radiation from other pyrolysis coal particles. The water and / or steam also sometimes passivates the pyrolysis coal by displacing air or oxygen in the surroundings of the pyrolysis coal after release from the cooling structure. In contrast to conventional water cooling, according to the invention the amount of water applied to the hot pyrolysis coal is so low that it can remain with the pyrolysis coal and does not need to be discharged separately. In various embodiments the spraying device is configured to supply an amount of water that is essentially evaporated when the pyrolysis coal has passed from the coal inlet until half the distance to the coal outlet.

[0020] In various embodiments the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in the first half, preferably in the first third, more preferably in the first quarter, more preferably in the first tenth, of the path from the coal inlet to the coal outlet. In the following, the coal inlet is also referred to as cooling inlet. In the following, the coal outlet is also referred to as cooling outlet.

[0021] In various embodiments dry cooling applies heat dissipation for removing thermal energy from the pyrolysis coal, the heat dissipation being selected from the group consisting of a solid cooling structure and a cooling gas, the solid structure preferably comprising an inner wall of the cooling structure.

[0022] That is, dry cooling means cooling without water in the liquid phase contacting the pyrolysis coal. In various embodiments, the cooling structure comprises a vessel to accommodate the pyrolysis coal. In various embodiments with the heat dissipation being the solid cooling structure, the cooling structure comprises the vessel and a shell enclosing the vessel and being spaced apart from the vessel so as to provide a flow path for a cooling fluid between the vessel and the shell. The inner wall of the vessel thus forms the inner wall of the cooling structure and is configured to apply heat dissipation as claimed. The inner wall is configured to transfer the thermal energy from the pyrolysis coal to the cooling fluid. In various embodiments, the cooling fluid is a liquid such as water, glycol, molten salt or mineral oil. In various embodiments the cooling fluid is a gas, such as an inert gas such as nitrogen, argon or sulfur hexafluoride. As the cooling fluid does not contact the pyrolysis coal, the cooling fluid can be recirculated with limited recycling and cleaning, if at all.

[0023] In various embodiments with the heat dissipation being the cooling gas, the cooling gas is within the cooling structure and directly contacts the pyrolysis coal. In various embodiments the cooling gas is an inert gas such as nitrogen, argon or sulfur hexafluoride. As the cooling gas does not undergo a phase change with the implied sudden expansion, the cooling gas does not raise as much dust as the water cooling. The cooling gas thus can be recirculated with limited recycling and cleaning.

[0024] Dry cooling often does not release as much dust as water cooling, as there is no phase change from liquid to gas with the implied sudden expansion of volume of the water. Accordingly, for embodiments with the heat dissipation being a solid cooling structure, the dust remains essentially with the pyrolysis coal, such that this dry cooling maintains the energy content of the pyrolysis coal.

[0025] In the present context, pyrolysis coal mostly having a temperature above its ignition temperature means that the amount of pyrolysis coal having a temperature above the ignition temperature is larger than the amount of pyrolysis coal having a temperature below the ignition temperature. Unless specified differently herein, the term "water" means water in the liquid phase, and the term "steam" means water in the gas phase.

[0026] In various embodiments, the apparatus further comprises a pneumatic conveyor system configured to receive the pyrolysis coal from the cooling structure and to move pyrolysis coal by means of an airflow; and a gaslock arranged to allow pyrolysis coal to pass from the cooling structure into the pneumatic conveyor system and to impede communicating fluid exchange between the cooling structure and the pneumatic conveyor system, the gaslock preferably being a rotary gaslock.

[0027] In various embodiments a further objective of the present invention is to provide a pneumatic conveyor system with improved transportation safety of hot pyrolysis coal and / or enhancing the overall reliability of the pneumatic conveyor system for hot pyrolysis coal. Previously it was found that hot pyrolysis coal particles can be conveyed by means of a pneumatic conveyor if they are cooled enough so that its surface temperature is below an ignition temperature. If the distance along which the coal is conveyed is sufficiently short and the coal is thereafter received in a safe atmosphere that impedes ignition, the risk of pyrolysis coal igniting during pneumatic conveying is substantially reduced. A typical safe atmosphere that impedes ignition may be a container filled with inert gas.

[0028] Even though pneumatic conveyors with hot pyrolysis coal work mostly well and safe, there remains a risk that some of the pyrolysis coal particles ignite in the pneumatic conveyor. As the ignited coal particles are usually received in an inert atmosphere, they stop burning, and safe handling and storing of the coal particles is still possible. However, such occasional ignition is not only a safety hazard, it also reduces the energy content of the processed pyrolysis coal and thus, the efficiency of the production of biocoal from biomass. In various embodiments, the pneumatic conveyor system's design considers factors such as temperature control, minimizing material degradation, and optimizing energy efficiency of the resulting pyrolysis coal, which are essential when conveying hot pyrolysis coal.

[0029] In various embodiments the apparatus further comprises a gaslock arranged to allow coal to pass from the cooling structure into the pneumatic conveyor system and to impede communicating fluid exchange between the cooling structure and the pneumatic conveyor system, the gaslock preferably being a rotary gaslock. Such a rotary gaslock is usually arranged much like a revolving door, that is with at least three panels arranged on a common rotary shaft and at least two panels at any point in time sealing against opposite inside walls of cylinder sections such that fluid communication through the airlock is permanently prevented or reduced. Other types of gaslocks can also be used. For example, a sliding gate valve or a double-flap valve could be employed to achieve the same function of allowing pyrolysis coal transfer while impeding fluid exchange between the cooling structure and the pneumatic conveyor system.

[0030] In various embodiments the spraying device is configured to disperse the water as a mist. Such a water mist has a comparably large surface area per volume and thus evaporates in the vicinity of the pyrolysis coal particularly effectively.

[0031] In various embodiments the spraying device comprises a spray nozzle spraying in a direction transversal to the conveying direction of the coal. This configuration exposes most coal to the evaporative of the sprayed water and cools the coal effectively.

[0032] In various embodiments the spraying device is configured to disperse water in a flat fan pattern extending transversal to a conveying direction of the coal. Spraying the water in a flat fan pattern extends a wetted portion across an extended part of a cross section of the conveyed coal. Such pattern can be achieved by selecting a corresponding spray nozzle and / or by arranging a series of spray nozzles in a corresponding pattern. In various embodiments, the spraying device comprises a pressure regulation mechanism. This pressure regulation mechanism allows for control over the water pressure, which affects the size and intensity of the mist as well as the overall flow expressed in liter per hour.

[0033] In various embodiments the spraying device is configured to disperse water in a conical pattern spraying in a direction transversal to a conveying direction of the coal.

[0034] In various embodiments the spraying device is configured to adjust a flow rate, a droplet size in the mist and / or a pattern of the dispersed water. In various embodiments, the spraying device may utilize different mechanisms to disperse water as a mist. For example, instead of using a nozzle-based system, the apparatus may employ ultrasonic technology to create the mist. Ultrasonic misting devices utilize high-frequency vibrations to break down water into droplets, resulting in a mist-like spray. Other embodiments may involve the use of a rotating disc or drum within the spraying device. This rotating component has a perforation or opening that allows water to be expelled as a mist when the disc or drum spins.

[0035] In various embodiments the spraying device is configured to increase a water content of the pyrolysis coal by less than 3%-points, preferably by less than 2%-points. For example, when the pyrolysis coal has a water content of 2% when entering the cooling structure, the spraying device increases the water content to a total amount of less than 5%, preferably less than 4%.The inventors have realized that this amount of water is enough to sufficiently reduce the temperature of the pyrolysis coal so that exothermal reactions are not continuing heating the pyrolysis coal while undergoing dry cooling. In various embodiments the spraying device is configured to disperse 20-50 l of water per hour per 1-1.5 metric ton of pyrolysis coal per hour. In various embodiments, the spraying device is configured to disperse 30 litres of water per ton of pyrolysis coal per hour.

[0036] In various embodiments the cooling structure is configured to cool the pyrolysis coal to a surface temperature below its ignition temperature.

[0037] In various embodiments the spraying device comprises a control unit including a microprocessor and a memory, the memory comprising instructions which, when executed by the microprocessor, cause the microprocessor to control the of any preceding embodiment, particularly to control the cooling structure, the pneumatic conveyor system and / or the spraying device. In various embodiments, the control unit, the microprocessor and the memory a digital circuits processing a computer program particularly written in a formal language. In further embodiments, the control unit, the microprocessor and the memory are configured as analogue circuitry implicitly storing the instructions.

[0038] In various embodiments the instructions for controlling the cooling structure comprise instructions for detecting a temperature of the pyrolysis coal and for adjusting a cooling action depending on the temperature. Adjusting the cooling action according to a detected temperature allows economizing the cooling action while allowing for extended operation times of the cooling structure.

[0039] In various embodiments the cooling structure comprises a conveyor to move the pyrolysis coal towards the coal outlet and the instructions for controlling the cooling structure comprise instructions for adjusting the movement of the conveyor depending on the temperature of the pyrolysis coal. In various embodiments the conveyor is a conveying screw moving the pyrolysis coal through the vessel of the cooling structure. In various embodiments the instructions for controlling the cooling structure comprise instructions for the conveyor to move the pyrolysis coal faster to the coal outlet, if the temperature of the pyrolysis coal is sufficiently low, and to move the pyrolysis coal slower to the coal outlet, if the temperature of the pyrolysis coal is too higher for being released earlier.

[0040] In various embodiments the instructions for controlling the pneumatic conveyor system comprise instructions for detecting an airflow velocity and / or an airflow temperature, and for adjusting at the pneumatic conveyor, the airflow velocity and / or a throughput of the coal. An increased airflow velocity at a given coal input reduces the amount of conveyed coal in a given section of the pneumatic conveyor system and thus reduces the number of coal particles that can ignite. Likewise reducing a throughput of coal reduces the number of coal particles that can ignite in a given section of the pneumatic conveyor system.

[0041] In various embodiments the instructions for controlling the spraying device comprise instructions for detecting a temperature of the coal and for adjusting water dispersing at the spraying device. If the coal temperature is below a threshold temperature, water dispersing can be reduced such that water can be saved and less water needs to dry off from the coal.

[0042] In various embodiments the apparatus further comprises a temperature sensor configured to detect a temperature of the coal inside the pneumatic conveyor and to indicate the temperature to the microprocessor, the temperature sensor preferably being sensitive to electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm.

[0043] In various embodiments the temperature sensor is arranged in a conveying direction of the coal prior to the spraying device, and the spraying device is configured to selectively spray the coal when the temperature sensor detects that the coal passes a temperature threshold.

[0044] In various embodiments the apparatus further comprises a torrefaction installation configured to provide pyrolysis coal into the cooling structure.

[0045] According to another aspect, a method for handling pyrolysis coal is provided, the method comprising: receiving pyrolysis coal mostly having a temperature above its ignition temperature; after receiving the pyrolysis coal, dispersing water at the pyrolysis coal; and after dispersing water, dry cooling the pyrolysis coal in an atmosphere impeding ignition.

[0046] An atmosphere impeding ignition particularly is an atmosphere having no oxygen. Dry cooling according to this aspect thus takes place in the absence of oxygen.

[0047] In various embodiments, the pyrolysis coal is received at a temperature to react exothermally. After dispersing water, the pyrolysis coal does not react exothermally.

[0048] Coming back to Fig. 1 the cooling structure according to the depicted embodiment is arranged to receive coal from a process chamber 1. In various embodiments the process chamber 1 is arranged to generally increase carbon density of organic- or fossil fuel-based carbonaceous materials. To that end a number of techniques are known, usually they include heat exposure of the carbonaceous material. In various embodiments the carbonaceous material undergoes a pyrolysis process. In some embodiments the carbonaceous material undergoes a torrefaction process such as the one described in WO 2015 / 084162 A1. In various embodiments the carbonaceous material enters the process chamber 1 as biomass, such as wood, bark, leaves or grass.

[0049] Once the carbonaceous material is turned into a predetermined grade of coal, that is, the carbonaceous material has the predetermined mass energy density, the coal usually has a temperature above its ignition temperature. Thus, before exposing the coal to air, it needs to be cooled. In the embodiment, the carbonaceous material is biomass such that the resulting coal will be referred to as pyrolysis coal in the following. The pyrolysis coal thus passes from the process chamber 1 to the cooling structure 10. In the cooling structure 10 the pyrolysis coal is cooled such that torrefaction is stopped and the pyrolysis coal has consistent characteristics once exiting the cooling chamber 10. In various embodiments the cooling structure 10 comprises a dry cooling element promoting a temperature decrease of the pyrolysis coal. In various embodiments the dry cooling element comprises a cooling liquid circulation structure for water or an oil based coolant (thermo oil). In various embodiments the dry cooling element comprises at least one channel allowing circulation of a cooling fluid adjacent to an inner surface of the cooling structure 10.

[0050] In various embodiments the interior of the process chamber 1 and at least a part of the interior of the cooling structure 10 are in fluid communication. In various embodiments the cooling structure 10 comprises a cooling chamber 11. In various embodiments the pyrolysis coal passes from the process chamber 1 to the cooling chamber 11.In various embodiments, the cooling chamber 11 comprises a cooling inlet 11a and a cooling outlet 11b. In various embodiments the dry cooling element forms a portion of the cooling chamber 11, the cooling chamber preferably forming an inner wall comprising the at least one channel allowing circulation of the cooling fluid adjacent to an inner surface of the cooling chamber 11. The inner wall comprises an inner surface for interfacing with the pyrolysis coal.

[0051] In various embodiments the process chamber 1 and the cooling chamber 11 are in fluid communication. Alternatively, the cooling chamber 11 comprises a gaslock at the cooling inlet 11a, such that fluid exchange between the process chamber 1 and the cooling chamber 11 is prevented and the pyrolysis coal passes from the process chamber 1 to the cooling chamber 11 through the gaslock. The gaslock is configured to allow the pyrolysis coal to pass while preventing gas exchange between the process chamber 1 and the cooling chamber 11.

[0052] In various embodiments the cooling chamber 11 comprises a conveying element 15. In some embodiments, the cooling chamber 11 comprises a conveying element 15 arranged to convey the pyrolysis coal from the cooling inlet 11a of the cooling chamber 11 to the cooling outlet 11b of the cooling chamber 11. In various embodiments the conveying element is a conveying screw 15 or a chain conveyor. In various embodiments the conveying screw 15 in the cooling chamber 11 is configured to continuously move and mix the pyrolysis coal such that different portions of the pyrolysis coal are in contact with the inner surface of the cooling chamber 11. Where the inner surface is cooled, particularly by the dry cooling element, the pyrolysis coal dissipates heat and cools down. In some embodiments the screw 15 has a shaft containing a passage for cooling fluid circulation. While only depicted to extend through a portion of the cooling chamber 11 in Fig. 1, in various embodiments the conveying element 15 extends from the cooling inlet 11a to the cooling outlet 11b.

[0053] In various embodiments the cooling chamber 11 comprises a purging arrangement dispensing an inert gas into the cooling chamber 11. The inert gas reduces oxygen exposure and impedes that the pyrolysis coal ignites. The inert gas cools down the pyrolysis coal in the cooling chamber 11. In various embodiments the inert gas is nitrogen or carbon dioxide.

[0054] In various embodiments the cooling structure 10 comprises a spraying device 14 configured to dispense water into the cooling chamber 11. The spraying device 14 is arranged in proximity to the cooling inlet 11a. The inventors have realized that the pyrolysis coal coming from the process chamber 1 has a temperature in a range that the pyrolysis coal can continue an exothermic reaction even inside the cooling chamber 11. That is, due to the exothermic reaction the pyrolysis coal continues to generate heat. In various embodiments the exothermic reaction generates more thermal power than the thermal power removed by the dry cooling element particularly constituted by the inner surface of the cooling chamber 11. The exothermic reaction thus may prevent the cooling of the pyrolysis coal. The inventors have further realized that spraying water on the pyrolysis coal effects a steep temperature drop such that the exothermic reaction is reduced or terminated.

[0055] In various embodiments the spraying device 14 is configured to disperse at least enough water that the combined cooling by the sprayed water and the dry cooling element reduces the temperature of the pyrolysis coal. In various embodiments the spraying device 14 is configured to disperse the water as a mist. The water mist effectively absorbs the heat from the pyrolysis coal, causing rapid evaporation and cooling. This process helps bringing the surface temperature of the pyrolysis coal below its ignition temperature. In various embodiments the spraying device 14 comprises a spray nozzle. In various embodiments the spray nozzle is configured to disperse water in a conical pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal. In various embodiments the spray nozzle is configured to disperse water in a flat fan pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal and extending transversal to a conveying direction of the conveying element 15. In various embodiments the spraying device 14 comprises a water supply such as a water tank and / or a connection to a public water source. In various embodiments the spraying device 14 comprises a pressurizing member, such as a water pump, configured to force water from the water supply through the spray nozzle into the cooling chamber 11.

[0056] In various embodiments the cooling structure 10 comprises at least two cooling chambers each cooling chamber configured to receive the pyrolysis coal from the process chamber 1 and / or from a preceding cooling chamber. In various embodiments each cooling chamber comprises a cooling inlet and a cooling outlet. In various embodiments each cooling inlet comprises a gaslock. Each gaslock is configured to allow the pyrolysis coal to pass while preventing gas exchange with the cooling chambers. The cooling chambers essentially correspond to the cooling chamber 11 described in the previous and following paragraphs. In some embodiments the cooling chambers are configured to move the pyrolysis coal upslope to allow gravity feeding through the following gaslock. In various embodiments only the first cooling chamber is configured with a water spraying device.

[0057] In various embodiments the handling apparatus comprises a control structure 16 configured to control an operation of the process chamber 1, the cooling structure 10, the pneumatic conveyor system 20 and / or the bulk storage 30. In various embodiments the control structure 16 comprises a microprocessor 16a and a memory 16b. The memory 16b comprises instructions which, when executed by the microprocessor 16a, cause the microprocessor 16a to control the process chamber 1, the cooling structure 10, the pneumatic conveyor 20 and / or the bulk storage 30. In various embodiments the control structure 16 is configured to control the spraying device 14, the dry cooling element and / or the conveying element 15.

[0058] In various embodiments the pneumatic conveyor system 20 comprises an inlet chute 21, a conveying channel 22 and a fan 24. The pneumatic conveyor system 20 is arranged to create an airflow strong enough to carry at least parts of the pyrolysis coal across some distance through the conveying channel 22. In various embodiments the pneumatic conveyor system 20 is arranged to convey pyrolysis coal from the cooling structure 10 to the bulk storage 30.

[0059] The inlet chute 21 is arranged to receive the pyrolysis coal from the cooling structure 10 through the cooling outlet 11b. In various embodiments the cooling structure 10 comprises a gaslock 13. The gaslock 13 is arranged between the cooling chamber 11 and the inlet chute 21. In various embodiments the cooling outlet 11b is arranged above the inlet chute 21 such that gravity causes the pyrolysis coal to move from the cooling outlet 11b into the inlet chute 21. In various embodiments the gaslock 13 is arranged between the cooling outlet 11b and the inlet chute 21. The gaslock 13 is arranged to allow pyrolysis coal to pass from the cooling chamber 11 into the inlet chute 21 of the pneumatic conveyor system 20 and to impede communicating fluid exchange between the cooling chamber 11 and the pneumatic conveyor system 20 as well as ambient air.

[0060] In some embodiments the conveying element 15 is configured to move the pyrolysis coal upslope to allow gravity feeding through the gaslock 13 and into the inlet chute 21.

[0061] In various embodiments the inlet chute 21 has a top opening 21c to receive the pyrolysis coal, an airflow outlet 21b opening towards the conveying channel 22 and an airflow inlet 21a arranged opposite to the airflow outlet 21b and allowing ambient air to enter the inlet chute 21 and the conveying channel 22. Pyrolysis coal disposed in the inlet chute 21 is dragged with the airflow 25 and conveyed through the conveying channel 22 towards the fan 24. In various embodiments the fan 24 is configured to create an airflow 25 through the pneumatic conveyor system 20, particularly through the conveying channel 21. In various embodiments the fan 24 is configured to operate accounting for the time the surface temperature of the pyrolysis coal is below the ignition temperature of the pyrolysis coal once cooling is stopped. Please note that in the airflow 25 the pyrolysis coal also cools at least initially as long as the velocity of the airflow 25 is different from the velocity of the pyrolysis coal.

[0062] In various embodiments the control structure 16 is configured to control the gaslock 13, the fan 24, and / or the airflow 25. In various embodiments the pneumatic conveyor system 20 comprises a temperature sensor 28 configured to detect a temperature of the pyrolysis coal inside the conveying channel 22. In various embodiments the temperature sensor is configured to indicate the temperature to the control structure 16. In various embodiments, the temperature sensor is sensitive to electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm. In various embodiments, the temperature sensor is an infrared radiation sensor. In various embodiments the control structure 16 is configured to adjust operations of the fan 24, the airflow 25, and / or the spraying device 14 dependent on the indication of the temperature sensor 28.

[0063] In various embodiments the conveying channel 22 is arranged with a separator 23. The separator 23 is arranged to remove solid particles from the airflow 25 conveyed through the conveying channel 22. In various embodiments the separator 23 is arranged to remove solid particles from the airflow 25 without using a filter. In some embodiments the separator 23 comprises a cyclone separator operating through vortex separation and / or a baffle assembly. The separator 23 is arranged to guide the pyrolysis coal into the bulk storage 30 and to allow the airflow 25 to pass towards the fan 24. In various embodiments the conveying channel 22 is arranged with a filter 26 between the separator 23 and the fan 24. In various embodiments the fan 24 is configured to supply enough pressure drop to account for the length, diameter and structure of the conveying channel 22, for the pressure drop across the separator 23 and the filter 26.

[0064] In various embodiments the bulk storage 30 is arranged to further cool the pyrolysis coal after conveying. The bulk storage 30 stores the pyrolysis coal at least until the remaining heat is insufficient to ignite the pyrolysis coal. In various embodiments the bulk storage comprises a container vessel 32. In various embodiments the bulk storage contains an inert gas impeding air exposure of the pyrolysis coal. With too little air, the pyrolysis coal cannot ignite even if the temperature is high. The inert gas in the container vessel 32 provides a safe atmosphere. In various embodiments the container vessel 32 is filled with nitrogen.

[0065] In various embodiments, the pyrolysis coal thus is processed in the following way: Pyrolysis coal produced by some process involving pyrolytic cracking of carbonaceous materials passes from a process chamber 1 to the cooling structure 10. In various embodiments the pyrolysis coal passes through a gaslock into the cooling structure 10. In various embodiments the pyrolysis coal passes into the cooling chamber 11. In various embodiments the spraying device 14 dispenses water into the cooling chamber 11 and onto the pyrolysis coal in proximity to the cooling inlet 11a. In various embodiments the pyrolysis coal contacts the dry cooling element. In various embodiments the cooling chamber 11 comprises a purging structure purging the pyrolysis coal with an inert gas. The inert gas may impede ignition of the pyrolysis coal and / or cool the pyrolysis coal. In various embodiments the conveying element 15 forwards the pyrolysis coal through the cooling chamber 11. In various embodiments the conveying element 15 mixes the pyrolysis coal to expose different portions of the pyrolysis coal to the dry cooling element, particularly the cooled inner wall of the cooling chamber 11. The conveying element 15 supports cooling of the pyrolysis coal.

[0066] In various embodiments the spraying device 14 disperses the water as a mist. In various embodiments the spray nozzle of the spraying device 14 disperses water in a conical pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal. In various embodiments the spray nozzle of the spraying device 14 disperses water in a flat fan pattern spraying in a direction transversal to the conveying direction of the pyrolysis coal and extending transversal to a conveying direction of the conveying element 15. In various embodiments the spraying device 14 receives water from a water tank and / or a public water source.

[0067] In various embodiments the cooling chamber 11 cools the surface of the pyrolysis coal to a temperature below an ignition temperature of the pyrolysis coal. In various embodiments the cooling chamber 11 cools the surface of the pyrolysis coal to a temperature of below 100 °C to stop torrefaction, preferably below 40 °C, more preferably below 20 °C. In various embodiments the residence time of the pyrolysis coal in the cooling chamber 11 is adjusted to control the resulting temperature of the pyrolysis coal. In various embodiments the pyrolysis coal passes from the cooling chamber 11 through the gaslock 13. In various embodiments the pyrolysis coal is gravity fed from the cooling outlet 11b of the cooling chamber 11 through the gaslock 13 and into the inlet chute 21. In some embodiments the conveying element 15 moves the pyrolysis coal upslope to allow gravity feeding through the gaslock 13 and into the inlet chute 21. In various embodiments the pyrolysis coal passes from the cooling chamber 11 to the pneumatic conveyor system 20.

[0068] In various embodiments the cooling chamber 11 is filled between 40% and 60% with pyrolysis coal. This allows for an earlier contact of the biocoal with the dry cooling element of the cooling chamber 11 than when the cooling chamber 11 is almost entirely filled.

[0069] In embodiments having at least two cooling chambers consecutive chambers have increased fill with the last cooling chamber preferably being filled more than 90% with pyrolysis coal. This maximizes residence time and cooling and thus occupancy rate of the last cooling chamber. In some embodiments the filling of the last cooling chamber also impedes air passing from the inlet chute 21 into a cooling chamber.

[0070] The pneumatic conveyor system 20 provides the airflow 25 from the airflow inlet 21a to the separator 23 and the fan 24 via the conveying channel 22. In various embodiments the pyrolysis coal is dropped from above into the airflow 25. As long as there is significant relative movement between the airflow 25 and the pyrolysis coal therein, the airflow 25 further cools the pyrolysis coal. The pyrolysis coal moves along the conveying channel 22 towards the separator 23. In the separator 23, the pyrolysis coal is removed from the airflow 25 such that the airflow passes towards the fan 24 and the pyrolysis coal passes to the bulk storage 30. The airflow within the conveying channel 22 aids in distributing the water evenly across the pyrolysis coal particles, improving thorough cooling.

[0071] In various embodiments the pyrolysis coal passes into the safe atmosphere of the container vessel 32. The pyrolysis coal remains in the container vessel 32 preferably until the remaining heat is insufficient to ignite the pyrolysis coal even in an atmosphere of ambient air. Once the pyrolysis coal is sufficiently cooled, the pyrolysis coal can be discharged to the outside of the container vessel 32. The cooled pyrolysis coal is allowed to contact ambient air for prolonged periods of time. In various embodiments the pyrolysis coal is discharged towards a transport means 35.

[0072] In various embodiments the control structure 16 controls the operation of the process chamber 1, the cooling structure 10, the pneumatic conveyor system 20 and / or the bulk storage 30. In various embodiments the microprocessor 16a controls the process chamber 1, the cooling structure 10, the pneumatic conveyor 20 and / or the bulk storage 30. In various embodiments the control structure 16 controls the spraying device 14 and / or the conveying element 15. In various embodiments the control structure 16 controls the gaslock 13, the fan 24, and / or the airflow 25. In various embodiments the temperature sensor 28 detects a temperature of the pyrolysis coal inside the conveying channel 22. In various embodiments the temperature sensor indicates the temperature to the control structure 16. In various embodiments, the temperature sensor detects electromagnetic radiation in a wavelength between 1,000 nm and 14,000 nm. In various embodiments the control structure 16 adjusts operations of the gaslock 13, the fan 24, the airflow 25, and / or the spraying device 14 dependent on the indication of the temperature sensor 28. In various embodiments, the control structure 16 adjusts the spraying device 14 to obtain a desired cooling rate and / or moisture content of the pyrolysis coal. In various embodiments the spraying device 14 is configured to increase a water content of the pyrolysis coal by less than 3%-points, preferably by less than 2%-points. It was found that with the spraying device being arranged close to the cooling inlet 11a and with the water dispersing taking place before most of the dry cooling takes place, only a small amount of water is sufficient to reduce the temperature of the pyrolysis coal and thus render dry cooling effective.

[0073] In various embodiments the pyrolysis coal is transferred to a power plant for energy or heat production. In further embodiments the pyrolysis coal is used to store carbon, to produce steel and / or to upgrade soil and / or to feed a gassifier.

[0074] While this description of the inventive process refers to some pyrolysis coal at specific process steps, please note that in various embodiments the handling apparatus is operated continuously such that pyrolysis coal is present at different stages of the handling apparatus at the same time. While this description primarily refers to pyrolysis coal, also different types of coal produced according to conventional processes may be handled in the apparatus according to the invention.

Examples

Embodiment Construction

[0011]Fig. 1 shows a handling apparatus for coal comprising a cooling structure 10, a pneumatic conveyor system 20 and a bulk storage 30. Before explaining the handling apparatus in detail, some general aspects of the invention will be discussed.

[0012]According to an aspect, an apparatus for cooling pyrolysis coal is provided, the apparatus comprising:

a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and a spraying device configured to disperse water;

wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

[0013]An objective of the present invention is to cool pyrolysis coal to a temperature safe f...

Claims

1. An apparatus for cooling pyrolysis coal, the apparatus comprising: - a cooling structure with a coal inlet and a coal outlet, the cooling structure being configured to receive pyrolysis coal mostly having a temperature above its ignition temperature at the coal inlet, to maintain the pyrolysis coal separate from ambient air and to dry cool the pyrolysis coal while moving the pyrolysis coal towards the coal outlet; and - a spraying device configured to disperse water; wherein the spraying device is configured to disperse the water at the pyrolysis coal inside the cooling structure in proximity to the coal inlet.

2. The apparatus of claim 1, wherein dry cooling applies heat dissipation for removing thermal energy from the pyrolysis coal, the heat dissipation being selected from the group consisting of a solid cooling structure and a cooling gas, the solid structure preferably comprising an inner wall of the cooling structure.

3. The apparatus of any preceding claim, further comprising a pneumatic conveyor system configured to receive the pyrolysis coal from the cooling structure and to move pyrolysis coal by means of an airflow; and a gaslock arranged to allow pyrolysis coal to pass from the cooling structure into the pneumatic conveyor system and to impede communicating fluid exchange between the cooling structure and the pneumatic conveyor system, the gaslock preferably being a rotary gaslock.

4. The apparatus of any preceding claim, wherein the spraying device is configured to disperse the water as a mist.

5. The apparatus of any preceding claim, wherein the spraying device comprises a spray nozzle spraying in a direction transversal to the conveying direction of the pyrolysis coal.

6. The apparatus of any preceding claim, wherein the spraying device is configured to disperse water in a flat fan pattern extending transversal to a conveying direction of the pyrolysis coal.

7. The apparatus of claims 1 to 5, wherein the spraying device is configured to disperse water in a conical pattern spraying in a direction transversal to a conveying direction of the pyrolysis coal.

8. The apparatus of any preceding claim, wherein the spraying device is configured to increase a water content of the pyrolysis coal by less than 3%-points, preferably by less than 2%-points.

9. The apparatus of any preceding claim, wherein the cooling structure is configured to cool the pyrolysis coal to a surface temperature below its ignition temperature.

10. The apparatus of any preceding claim, further comprising a control unit including a microprocessor and a memory, the memory comprising instructions which, when executed by the microprocessor, cause the microprocessor to control the apparatus of any preceding claim.

11. The apparatus of claim 10, wherein the instructions for controlling the cooling structure comprise instructions for detecting a temperature of the pyrolysis coal and for adjusting a cooling action depending on the temperature.

12. The apparatus of claim 11, wherein the cooling structure comprises a conveyor to move the pyrolysis coal towards the coal outlet and the instructions for controlling the cooling structure comprise instructions for adjusting the movement of the conveyor depending on the temperature of the pyrolysis coal.

13. The apparatus of claims 10 to 12, wherein the instructions for controlling the spraying device comprise instructions for detecting a temperature of the pyrolysis coal and for adjusting water dispersing at the spraying device.

14. The apparatus of any preceding claim, further comprising a torrefaction installation configured to provide the pyrolysis coal into the cooling structure.

15. A method for handling pyrolysis coal, the method comprising: - receiving pyrolysis coal mostly having a temperature above its ignition temperature; - after receiving the pyrolysis coal, dispersing water at the pyrolysis coal; and - after dispersing water, dry cooling the pyrolysis coal in an atmosphere impeding ignition.

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