Unit for continuous production of steelmaking coal and energy using microwave-assisted pyrolysis

Abstract

The present invention patent application relates to a reactor and its peripheral equipment, referred to as a unit for continuous production of steelmaking coal and energy, used in the production of charcoal, oil and non-condensable gases from the transformation of wood by means of pyrolysis assisted by non-ionising microwaves on a metal conveyor belt and in a controlled atmosphere, characterised in that it uses several low-power microwave-generating sources distributed along the cavity, characterised in that it uses an automatic control system that guarantees the safety of the charcoal production, ensuring stable physical and chemical properties. It is distinguished by its high production capacity; full utilisation of the timber, transforming it into (3) products; the absence of pollutants; a reduction in the industrial process cycle from (288) hours to (3) hours; a control system capable of estimating the physical and chemical parameters of the coal, and a safety and self-diagnosis system.

Description

Continuous Production Unit for Metallurgical Coal and Energy by Microwave-Assisted Pyrolysis FIELD OF THE INVENTION

[0001] The invention described in this patent application relates to an automatic device, called a Continuous Production Unit for Metallurgical Coal and Energy, and its peripherals for the production of charcoal, oil, and non-condensable gases from the continuous pyrolysis of wood through the application of non-ionizing electromagnetic microwave energy. FUNDAMENTALS OF THE INVENTION

[0002] Traditionally, charcoal production is done using large kilns built of masonry or metal materials in various shapes and sizes, but the operating principle is the same for all: some burn part of the spilled wood to generate the energy needed for carbonization, while others use external combustion to generate the necessary heat. The process is known as carbonization.

[0003] These kilns are loaded and unloaded manually, with a production cycle of ten to fifteen days, the quality and quantity of charcoal produced varying according to their size. The production process is basically composed of three distinct phases: the first consists of drying the wood; the second, the carbonization itself; and the last, the cooling of the charcoal.

[0004] In conventional processes, wood carbonization occurs through the supply of energy inside the furnace, by burning part of the spilled wood, raising its internal temperature and triggering a process of water release and volatilization of holocellulose and lignin molecules. Up to a temperature of around 270°C, this physicochemical process is endothermic, requiring an energy supply, and exothermic at higher temperatures, where energy is generated from the carbonization reactions, becoming a self-sustaining process. These physicochemical transformations give rise to two types of products: charcoal and smoke. The latter is composed of two products: non-condensable gases (NCG), a mixture of carbon monoxide, carbon dioxide, REPLACEMENT SHEET (RULE 26) methane, nitrogen and hydrogen; and another made up of pyroligneous acids and tars, known as bio-oil, pyrolysis oil or simply oil.

[0005] Traditional furnaces typically release this smoke into the atmosphere, producing large quantities of highly polluting greenhouse gases. Since there are no other economically viable technologies for coal production, steel industries are forced to use these processes with various variations, but attempting to reduce the environmental impact through smoke combustion, which increases production costs.

[0006] The basic difference between wood pyrolysis and carbonization processes lies in the fact that the former promotes the thermal degradation of wood in an oxygen-free atmosphere, while the latter does not, as it requires air injection to burn part of the spilled wood. The pyrolysis chemical reaction is activated by the application of external thermal energy, transforming the wood into charcoal.

[0007] Because pyrolysis does not allow air into the furnaces, the effluent gases have a high calorific value compared to the smoke from a conventional carbonization furnace. This is because when air is allowed in, in addition to burning some of the wood and the smoke generated, a large amount of nitrogen (an inert gas) is injected, reducing the energy density of the effluents and making the use of the smoke practically unfeasible. It should be noted that air contains 21% oxygen, 78% nitrogen, and 1% other components.

[0008] In masonry kilns, approximately 13% of the poured mass of wood is burned to supply energy to the process. Ignition is achieved using embers and kindling placed through holes in the kilns, called "tatus" (a type of fire hole). The combustion process extends throughout the wood bed by controlling the air intake. The hot gases generated by combustion rise due to density differences, creating flows that pass through the rest of the wood, transferring heat to the bed. After the drying phase, the wood thermally degrades, giving rise to charcoal. The carbonization cycle lasts around 3 to 5 days, varying depending on the humidity and size of the wood blocks, the climate, the maintenance of the kilns, and the internal temperature.

[0009] After carbonization, cooling can be natural or forced. For natural cooling, all holes are sealed with clay, waiting for the kiln to reach the appropriate temperature for discharge, which is between 60 and 80°C. REPLACEMENT SHEET (RULE 26) This type of cooling can take between 7 and 10 days, depending on the dimensions of the kiln. However, for forced cooling, the waiting time is 5 to 7 days, and it is carried out by injecting sprayed water inside the kiln. The volume of water injected represents a consumption of approximately 200 liters per cubic meter of charcoal produced. Thus, the average production cycle per masonry kiln is around 12 days.

[0010] This patent application proposes the construction of an industrial pyrolysis reactor that replaces the conventional heat source used, wood burning, with an electric one, derived from microwaves, where heat is generated by the action of the waves on the component particles of wood (lignin, cellulose, hemicellulose and extractives), causing intense molecular vibration, rapid heating and thermal degradation of the wood, transforming it into charcoal, non-condensable gases (NCG) and oil. This technological substitution produces spectacular effects in reducing the production cycle from 12 days or 288 hours to 3 to 4 hours per reactor. This is a reduction of almost 90% in the production cycle.

[0011] Heating dielectric materials with microwave energy has been known for a long time. For example, one can cite the patent granted in 1946 to WESTINGHOUSE ELECTRIC CO for this purpose: US2466853 - APPARATUS FOR MICROWAVE HEATING OF DIELECTRIC MATERIALS. And there are many others such as: US2612596 / 1947 - MICROWAVE HEATING (RAYTHEON MFG CO); US2495170 / 1950 - MICROWAVE HEATING OF DIELECTRIC MATERIALS (WESTINGHOUSE ELECTRIC CO).

[0012] Specifically for wood heating, there is a reference in the patent granted in 1965 in the United Kingdom to the company HUSQVARNA VAPENFABRIKS AB, GB1 112641 - IMPROVEMENTS IN OR RELATING TO APPARATUS FOR HEAT TREATMENT OF ARTICLES. “It is a microwave heating apparatus comprising a tunnel with a slot arranged longitudinally on a wide side symmetrically about the longitudinal centerline of the wider side, means for conveying materials (tobacco, wood, food) through the tunnel, and a microwave generator connected to the slot. Portions of materials are fed in any desired sequence by pistons into the tunnel and conveyed through variable chain rollers. Energy from two REPLACEMENT SHEET (RULE 26) Microwave generators located in cabinets are guided through waveguides to the tunnel.

[0013] The oldest international patent granted for drying and pyrolysis of wood was CN102776008 / 2012 - CONTINUOUS PRODUCTION LINE DEVICE FOR MICROWAVE DRY-DISTILLING AND CRACKING BIOMASS. The invention discloses a continuous production line device for microwave dry distillation and cracking of biomass. The continuous production line device comprises a carbonization furnace housing and a conveyor and transmission belt, wherein the conveyor and transmission belt are arranged in the carbonization furnace housing; the carbonization furnace housing is divided into a microwave distillation and cracking chamber and a cooling chamber; microwave units are arranged in the microwave distillation and dry distillation chamber housing; air ducts are respectively arranged above a preheating region and a drying region;The ends of the air ducts are connected to air blowers controlled by a voltage-controlled frequency inverter; a nitrogen gas cooling heat exchanger is arranged inside the cooling region; an air inlet pipe is configured at one end of the nitrogen gas cooling heat exchanger; an air outlet pipe is connected at the other end of the nitrogen gas cooling heat exchanger; the air outlet pipe is connected respectively to the frequency-controlled air blowers in the preheating and drying regions; an air outlet is arranged in a high-temperature dry distillation region with micro-positive pressure;The air outlet is connected to air blowers. Although the process appears continuous, it should be noted that in-line cooling greatly reduces the conveyor speed, as the cooling time of the coal, even if forced, is much longer than that of pyrolysis. This characteristic prevents the use of this equipment in steelmaking. Furthermore, there is a huge difference in the heating dynamics of microwaves and convection. Redirecting the heated nitrogen to the pyrolysis chamber does not contribute to energy reduction, since one phenomenon is much faster than the other. This preheating proposal is unnecessary. REPLACEMENT SHEET (RULE 26)

[0014] There are other patent applications for the production of charcoal using microwaves: • BR 112012022133-7 / 2012 - METHOD FOR TREATING BIOMASS MATERIAL, CARBONIZED SOLID PRODUCT AND / OR PYROLYSIS GAS, USE OF CARBONIZED SOLID PRODUCT, COMPRESSED PRODUCT, AND METHOD FOR PROCESSING A CARBONIZED SOLID PRODUCT that describes a microwave-assisted batch pyrolysis system in a cylindrical cavity with nitrogen injection, processing pieces of wood up to 30 cm in size. 3 That is, wood chips of uniform size, which must be agitated during the process, obtaining charcoal with fixed carbon content on the order of 31%, which is very low by industrial standards. • US20130032464 / 2013 - MICROWAVE ASSISTED FLASH PYROLYSIS SYSTEM AND METHOD USING THE SAME, describes an industrial-use equipment for rapid pyrolysis that produces powdered charcoal, non-condensable gases, and bio-oil. The present invention provides a rotary microwave-assisted rapid pyrolysis system to perform pyrolysis on an industrial scale. The finely ground raw material is admitted by means of augers into the cavity where it will receive the microwave action. The carbonized material is removed by gravity, and the gases exit through a specific orifice. The production of powdered charcoal does not meet the needs of the steel industry, which requires charcoal with a much larger particle size so that the gases in the blast furnaces have a certain permeability and pass through the charcoal and iron ore. This application bears some resemblance to US patent BR 1 12012022133-7 / 2012. • CN104927885 / 2015 - METHOD FOR PRODUCTION Charcoal according to microwave technology, which describes a method of applying microwaves to REPLACEMENT SHEET (RULE 26) The production of charcoal, but applied to small particles of wood, requires the wood to be crushed and dried before the process. The application does not mention how to obtain the charcoal, only stating that applying microwaves to dry wood particles will produce charcoal, but it does not refer to the physicochemical specifications of the resulting product. Patents over 20 years old already mentioned microwave heating, which consequently implies the pyrolysis of the material. • CN 1 10655937 / 2020 - MICROWAVE CHARCOAL This project, titled "Preparation Device Capable of Recycling Biomass Oil," describes a household microwave oven transformed into laboratory pyrolysis equipment for the recovery of non-condensable oils and gases. The project aims to produce small quantities of charcoal for pharmaceutical use and is not applicable to the iron and steel industry. • W02020064598 / 2020 - MICROWAVE PYROLYSIS REACTOR, this Norwegian invention provides a microwave pyrolysis reactor comprising a vertical inner tube element and a housing, wherein the inner tube is made of a microwave-transparent material and is disposed within a cavity and comprises a first open end and a second open end; the housing comprises a first inner surface, enclosing an annular space around the inner tube element, a waste inlet, a solids outlet, a gas outlet and a port for a microwave waveguide. The vertical cylindrical tube has a configuration similar to a furnace or blast furnace, albeit with small dimensions, but presents serious design problems as it does not explain how the material will be removed from inside the tube, since the tar produced by the chemical reaction of pyrolysis will adhere to the inner walls. REPLACEMENT SHEET (RULE 26) making product removal difficult, and some of it will be carried away by gravity along with the tar-contaminated coal.

[0015] In general, it is observed that all previous patent applications lack technical characteristics that meet the needs of the metallurgical coal production industry, such as: intense and continuous coal production or large batch production, scalability of production capacity according to industry needs, production control to ensure process repeatability and product quality, as well as safety against explosions and utilization of pyrolysis effluents to avoid environmental liabilities.

[0016] Charcoal is basically composed chemically of carbon, volatiles, ash, and moisture. The ratio of carbon mass to charcoal mass is known as the fixed carbon content, given as a percentage, and the stability of this ratio is one of the most important indicators for quality control of metallurgical coal.

[0017] The wood to be processed in charcoal production equipment is basically composed of lignin, hemicellulose, and cellulose. The mass of each component in the wood varies depending on the species, age at harvest, and soil where it was planted. Therefore, industrial equipment must be insensitive to variations in the chemical characteristics of the wood and produce charcoal with stable physicochemical characteristics, especially fixed carbon and mechanical strength within the specifications desired for an industrial blast furnace.

[0018] Metallurgical coal has severe limitations regarding mechanical strength and physicochemical composition, as it is used as a reducing agent for iron ore (Fe2O3) in pig iron. In simple terms, the carbon in the coal combines with the oxygen in the iron ore inside the blast furnace, transforming it into liquid iron (Fe) and releasing CO2 into the atmosphere. Therefore, the amount of carbon in the coal mass, fixed carbon, is fundamental to the efficiency of the production process. The higher the fixed carbon content, the greater the iron production, but the coal must have a certain mechanical resistance to compression to support the iron ore load inside the blast furnace. There is an inversely proportional relationship between fixed carbon content and the mechanical strength of charcoal; that is, the higher the carbon content, the greater the resistance. REPLACEMENT SHEET (RULE 26) The lower the mechanical resistance, the lower the carbon content. Therefore, industrial charcoal production processes need control systems that guarantee a balance between fixed carbon content and mechanical resistance. This is something that is not mentioned in any of the previous patent applications. The absence of an intelligent control system renders any invention unviable for industrial use.

[0019] Furthermore, any method of heating wood above 270 degrees Celsius, with low ventilation, will transform it into charcoal, whether in a bonfire, an electric oven, a wood-fired oven, a microwave oven, or any other system. Microwave heating itself does not constitute an invention, but the controlled application of microwaves with the intention of obtaining charcoal with specific physicochemical characteristics for use in the steel industry demonstrates inventive activity and industrial applicability, which is the focus of this patent application.

[0020] In a concise analysis of the inventions described above, several common points can be listed that prevent the use of these inventions in the steel industry. These are: • None of them have an intelligent production control system, which implies charcoal production with high physicochemical variability and low repeatability; • No patent presents a truly continuous coal production process; all use batch reactors, even those with tunnels, because cooling occurs in line with the conveyor belt; • They do not clearly describe how the furnaces are fed and discharged, except for one that uses auger screws and another that uses a piston, both of which present operational difficulties if the biomass particle size deviates from the appropriate dimensions, something common in the day-to-day operations of the industry; • The lack of automation in feeding wood into the reactors increases labor costs, moving in the opposite direction of the financial sustainability of an industrial project; REPLACEMENT SHEET (RULE 26) • All of them work with biomass with low particle size, generally producing powdered charcoal, although in steelmaking processes a larger particle size is desirable, preferably pieces with minimum edges of 5 cm; • The inventions produce charcoal quickly compared to traditional processes. However, they have a small production capacity, which is further reduced by the fact that the charcoal is cooled in the cavity where it was processed. Only one application has a nitrogen cooling chamber, but integrated into the equipment; • They do not continuously produce non-condensable gases and oil, which makes it difficult to reuse these pyrolysis effluents, creating an environmental liability according to Brazilian legislation; • Some inventions inject nitrogen to obtain an inert atmosphere and prevent explosions, but it mixes with the pyrolysis vapors, drastically reducing the calorific value of the non-condensed gases and increasing the cost of production; • The absence of continuous gas and oil production prevents the use of Brayton-Rankine combined cycle renewable energy generation; • The absence of a safety system against operational errors and explosions prevents the use of the inventions described in a safe industrial environment, since the atmosphere inside the reactors is explosive; • Currently, any industrial equipment requires integration with asset management systems and needs to integrate with Industry 4.0 technologies. Therefore, inventions focused on industry must be born with intense automation and process control, something that doesn't make sense for equipment with small production runs like those presented in the previous patents. REPLACEMENT SHEET (RULE 26)

[0021] Another difficulty found in all patents lies in the lack of study on microwave propagation in pyrolysis cavities. One patent proposes a cylindrical cavity that is not suitable for propagation, as there is too much wave reflection on the magnetron antennas, leading to their burnout. Magnetron tubes are electrical devices that emit energy through electromagnetic microwaves. There is no mention of a study on microwave propagation within furnaces or reactors. For example, cylindrical cavities promote wave cancellation when installed diametrically opposite each other in a tube, or, due to the cavity geometry, there will be microwave reflection on the magnetron tube antennas, leading to their rapid deterioration.Therefore, a study of microwave propagation in cavities is a necessary requirement to obtain equipment with efficient microwave distribution so that each piece of wood receives the same amount of energy, producing charcoal with homogeneous physicochemical characteristics. This is a fundamental and necessary condition for any invention that aims for large-scale production with low energy consumption and high durability.

[0022] The use of conveyor belts for microwave equipment is not new, and its use can be observed in a patent registered in 1957, number 2,887,584, serial number 687,632 in the USA, entitled ELECTRON IRRADIATION APPARATUS, and in Great Britain in 1959 as GB823545 - NEW PROCESS FOR EXTRACTING OIL FROM CASHEW-NUTS AND APPARATUS FOR CARRYING THIS OUT, a continuous process for extracting cashew nut oil. The container is replaced by a tunnel or cavity with a geometry suitable for the process, but always with a transparent microwave-resistant conveyor belt. Note that the tunnel is suitable for the process and not for the propagation of microwaves. A compromise must be struck between the two.

[0023] The use of a material conveyor belt appears more recently in Brazil in application number PI 0104918-6 B1 / 2001 - PROCESS FOR STERILIZING WOOD OR BAMBOO PRODUCTS, which also uses a transparent microwave conveyor belt, in this case, made of fiberglass or fiberglass with Teflon. This is not feasible for large equipment processing several tons, as fiberglass and Teflon belts do not have adequate mechanical resistance, and are only applicable to small equipment. REPLACEMENT SHEET (RULE 26)

[0024] Finally, none of the published patents make any reference to the efficiency of the methods and equipment, energy consumption as a function of the mass of material to be pyrolyzed, or the final quality of the charcoal: fixed carbon content, moisture, ash, mechanical resistance, and control of pollution generated by the release of gases into the atmosphere. They use microwave generating sources with energy applied at focal points. They also do not use refined power control to minimize energy consumption per cubic meter of charcoal.

[0025] This application, in addition to not presenting the drawbacks described above, was designed to work with various microwave generating sources arranged along a metallic cavity, through a detailed study of microwave propagation, using a high-strength, non-transparent metallic conveyor belt to transport wood logs, 20 cm high and of variable diameter, to be pyrolyzed. This is controlled by a temperature and conveyor movement control system with multiple process control loops with negative feedback, in order to guarantee a specific wood heating curve and obtain charcoal with desired physicochemical characteristics. The control system regulates the amount of energy each portion of wood receives and possesses the necessary characteristics for integration with Industry 4.0 technologies.

[0026] The Continuous Metallurgical Coal and Energy Production Unit innovates in the following aspects: firstly, in the process, reducing the carbonization cycle time of industrial equipment from 10 to 15 days to 3 to 4 hours. It presents an electricity consumption 3 times lower than that generated by pyrolysis effluents: 1 MWh of electricity is consumed per ton of coal produced, and 3.3 MWh of electricity is generated with pyrolysis residues in a combined cycle power plant. That is, there is a surplus of 2.3 MWh for each ton of charcoal produced. It evolves the batch process to a continuous one, allowing the installation of a state-of-the-art industrial process control system and meeting the requirements of Industry 4.0 and the most stringent environmental legislation, since all effluents are used as energy sources for a thermoelectric power generation system.Secondly, the equipment is industrial-grade with an estimated lifespan of 20 years; it uses a conveyor belt. REPLACEMENT SHEET (RULE 26) Non-transparent carbon steel metallic microwave tunnel with lengths exceeding 36 m, which may be greater or less depending on production capacity; it has a tunnel-shaped cavity in carbon steel with dimensions varying from 1.2 m to 2.4 m in width and variable height depending on the type of conveyor belt, not limited to these dimensions; thermal insulation along the entire tunnel; use of several microwave generating sources installed at the top of the tunnel, at a frequency of 2.4 MHz, low power, 1 to 3 kW, distributed along the cavity at a distance of 2 or 3 wavelengths (24 cm or 36 cm) between them and at a distance of 2 or 3 wavelengths between the sources and the bed of material to be treated; it has a continuous and automatic wood feeding and air extraction system; wood detection sensor on the conveyor belt; continuous coal discharge system; forced extraction of pyrolysis gases;System for separating the liquid fraction (oil) from the non-condensable fraction; control system with advanced inferential control technique for fixed carbon or gravimetric yield, automatically adjustable according to the final objective of pyrolysis; with temperature measurements along the cavity; conveyor speed control, allowing the production of charcoal with stable physicochemical characteristics within pre-specified parameters; it also has a positive pressure control system; safety valves with anti-explosion control system; automatic cleaning system for the cavity and conveyor; hot-swapping of electrical components and high production capacity: 150 to 300 tons of charcoal per month, 160 to 330 tons of oil and 140 to 280 tons of non-condensable gas with low nitrogen content.

[0027] The present invention was created in modules to facilitate increasing the size of the reactor, in order to add more modules according to the needs of the charcoal production industry and reduce production costs. Each module has a length of 6 meters and a width of 1.2 to 2.4 meters, with variable height, but ensuring that the distance between the microwave emitting valves and the metal conveyor belt is 24 or 36 cm, with no intermediate values. Always values ​​that are multiples of a wavelength for the frequency of 2.4 GHz.

[0028] Since the inventions cited in this application do not have production capacity compatible with the industry, the invention proposed here will be... REPLACEMENT SHEET (RULE 26) Compared to an industrial masonry kiln model with a monthly production capacity of 140 cubic meters of charcoal or 28 tons, it is common for charcoal-producing industries to use batteries with 400 masonry kilns. It is important to remember that conventional carbonization burns part of the discarded wood to generate heat for the process, which reduces the wood's beneficiation capacity, lowering the gravimetric yield (the ratio between the dry mass of charcoal and the dry mass of discarded wood) to average values ​​of 25%, and impoverishing the gases produced. These kilns have only two monthly production cycles, each lasting an average of 12 days. Normally, to avoid releasing greenhouse gases into the atmosphere, producers burn them to reduce the environmental impact.This implies that a planted forest, considering the mass of the wood, will only produce the equivalent mass of 25% of the planted area. Thus, % of the forest will literally be transformed into polluting and toxic smoke. No industrial process can withstand such losses, but it does because there is no technology available to solve this problem, which this invention definitively solves.

[0029] Figure 1 shows two graphs, the first comparing the gravimetric yields obtained by the two technologies: pyrolysis performed by the invention presented here and conventional industrial furnaces. The second compares the amount of carbon recovered from wood for industrial use, whether in the production of thermoelectric energy or in its use by the steel industry as a reducing agent for blast furnaces.

[0030] Considering the mass of wood A, Figure 1, fed into both pieces of equipment, it can be compared that invention B produces three products: charcoal, oil, and non-condensable gas in proportions of 33%, 40%, and 27% of the original mass of wood, which may vary depending on the industrial objective for the charcoal. In C, the average gravimetric yield of conventional kilns can be read as being around 25% in relation to the mass of wood. This implies that this invention produces 32% more charcoal. This means that the planted area could be 32% smaller, freeing up significant financial resources applied to the forest. Furthermore, the conventional process produces nothing but smoke, which will require consuming wood to be burned and avoid environmental impacts. While this invention, REPLACEMENT SHEET (RULE 26) It also produces oil, with an average calorific value of around 4800 kcal / kg, and gas with an average calorific value of 980 kcal / kg.

[0031] Figure 2 illustrates the use of pyrolysis effluents from invention F in the production of electrical energy through the use of a gas turbine G, fueled by pyrolysis oil and gases, and a boiler and steam turbine generator set H, fueled by the combustion gases from the gas turbine. As mentioned earlier, the surplus of renewable electrical energy produced is on the order of 2.3 MWh, shown in I in Figure 2, per ton of charcoal produced. This implies that a company with a battery of 400 furnaces, producing 1,200 tons of charcoal per month, fails to produce the equivalent of 25,760 MWh of energy, or 25.76 GWh / month. It is truly a waste to use these archaic technologies.

[0032] In terms of comparing the number of industrial equipment, considering that this invention can produce 300 tons of charcoal per month, the number of kilns, originally 400, would be reduced to 37, implying a drastic reduction in the number of employees and production costs, without considering the financial gains from energy generation, the economic gains from higher gravimetric yield, and the lower demand for planted area. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention could be better understood through the following detailed description, in accordance with the attached Figures, where: Figure 1 presents two graphs that allow a comparison of production between two industrial technologies: the invention and that of industrial masonry furnaces. Figure 2 illustrates an energy balance of the use of effluents in the production of electrical energy using the Brayton / Rankine combined cycle using a cascaded gas turbine with a boiler and steam turbogenerator. Figure 3 presents an overview of the invention, a horizontal pyrolysis reactor showing the inlet, drying and pyrolysis modules, gas outlet modules and charcoal discharge. Figure 4 highlights the input module for wood feeding. Figure 5 shows an automatic wood log feeding system for the target reactor of this invention. REPLACEMENT SHEET (RULE 26) Figure 6 illustrates details of the operation of the automatic pellet feeding system in the reactor. Figure 7 shows the locations where the microwave emitter kits are installed. Figure 8 highlights the gas outlet module with the safety valve and activated carbon. Figure 9 shows how gases are collected from the reactor and the system for separating liquids and non-condensable gases. Figure 10 identifies the electrical control and operation panels. Figure 11 shows the simulation results of a cavity designed to reduce energy consumption and improve the distribution of microwaves over the wood inside the invention. Figure 12 presents a synthetic diagram of the control and automation system architecture of the industrial plant. Figure 13 shows the screen of the Supervision and Control System that allows remote operation of the reactor. DESCRIPTION OF THE INVENTION

[0034] The Continuous Metallurgical Coal and Energy Production Unit, Figure 3, is a horizontal, continuous pyrolysis reactor constructed of 3 / 8 inch or 9.5 mm thick carbon steel plates, composed of four parts: wood feeding module 1, cavity modules with conveyor belt 2 and microwave emitter kit installation 3, walkways for access to the back of the equipment 4, output module 5, containing two outlets 6 for capturing pyrolysis gases, an explosion-proof valve 7 and a charcoal collection subsystem 8. The wood introduced into the feeding module 1 is transported by a metal conveyor belt driven by a geared motor assembly 9 inside the hermetic cavities 2, receiving energy, in a controlled manner, from microwaves 3 installed along the cavity modules 2, ultimately producing 8 metallurgical charcoal with a pre-determined physicochemical specification, pyrolysis oil and non-condensable gases extracted in 6.To operate the microwave emitting valves 3, microwave kits 26 are used, Figure 7, and the energy is supplied by means of electrical cables that pass through the cable trays 10 installed along all the cavities 2 that come out of the panels 1 1 that contain the electrical drive and protection devices. REPLACEMENT SHEET (RULE 26)

[0035] The conveyor belt used in this invention is a commercially available product widely used in the sugar and alcohol industry. It possesses the necessary robustness and is driven by chains attached to the underside, pulled by a toothed wheel on shafts arranged along the cavities. The last shaft, in the output module, is coupled to a geared motor with the necessary power and torque for the function. Each shaft has a speed sensor so that the control system is informed and ensures that all shafts have the same speed. The slightest variation in speed between shafts will indicate serious problems. The equipment will need to be stopped for maintenance.

[0036] Continuous wood feeding occurs in two ways: manually or automatically, depending on the industry's preference. Manual feeding, Figure 4, is simple, quick, and practical, but is only recommended for use with a maximum of 4 reactors in parallel. When this number is greater, it is recommended to use the automatic feeding system, Figure 5, as it reduces labor costs. Manual feeding is done by means of a device, Figure 4, which allows the wood logs to be placed on the table 12 and the operator to manually open the gate valve 13, pushing the pieces of wood into the compartment 14 of the inlet module 1. The valve 13 is activated to be closed, then the air is removed by suction at 15 and the piston 16 is activated, lowering the wood to the level of the metal conveyor belt.Next, piston number 17 pushes the batch of logs onto conveyor belt 18 of the reactor, and subsequently they are compacted by a mechanical system with springs 19 to eliminate any empty space or prevent any log from tipping over. After the operator has fed the wood logs into 14, Figure 4, the remaining operations are automatic and monitored by sensors to ensure that the actuators, pistons, are activated in the correct sequence and timing. The dimensions of this module must match those of the cavity. If the cavity is 1.2 m wide, the feeding table must also have this dimension, as well as all gate valves used in this module.

[0037] The automatic feeding system, Figures 5 and 6, recommended when there are more than 4 reactors in parallel, involves the use of a log organization system known in the timber industry that arranges all the logs upright on a conveyor belt 20. This set of logs is organized on this conveyor belt 20 external to the furnace, connected to the feeding module 1, in such a way as to REPLACEMENT SHEET (RULE 26) Fill compartment 14 exactly. The set of logs is received by a device 22 that keeps them upright and informs the wood presence sensor installed on the conveyor belt to open the gate valve 13, which, once activated, causes the device 22 to rise and, subsequently, activates the piston 23 that pushes the set of logs into compartment 14. Once the logs are inside compartment 14, the process continues exactly as described in the manual and previously.

[0038] Before piston 17 is activated, the conveyor belt stops for one second until the stroke of piston 17 is complete and is automatically restarted. There is synchronization between the feed speed of the wood billets and the speed of the conveyor belt, so the interruptions are only to allow the activation of piston 17.

[0039] The wood is transported to the first microwave module of the reactor, Figure 7. The reactor can have several modules depending on the desired production capacity. Each module, as already mentioned, has dimensions that are multiples of a wavelength (12 cm), either in height or width. The thickness of the carbon steel sheets is 9.5 mm, but not limited to this, and is covered with a 50 mm thick rock wool insulation blanket, which is protected by a 3 mm thick sheet, although it can be thicker.

[0040] When the material presence sensor on the conveyor belt detects the wood chunks, it informs the process controller, which then activates the microwave emitter kits above the chunks, rapidly heating them through the action of microwaves on the water particles within the wood. To prevent heat from escaping the reactor, the 24 modules, called cavities, have thermal insulation to withstand temperatures up to 750°C. eC. There are also several windows 25 on the back of the modules for installing the waveguide assembly with the microwave emitter kits 26, where the generator valves are located. Kits with power up to 1 kW are air-cooled by fans, and with higher power, cooling is done by a closed circuit with water and a cooling tower. Except for the first module, all have at least two temperature sensors 28 installed that measure the ambient temperature near the billets. To have fine adjustment in temperature control, four temperature sensors are installed in the last module. There is a computer program that performs a REPLACEMENT SHEET (RULE 26) The internal temperature of the log is inferred from the external temperature measurement and reported to the control system.

[0041] When the material reaches the end of the last module 5, Figure 3 (usually five to six modules with microwaves are used), it will already be completely pyrolyzed and transformed into charcoal. Pyrolysis smoke will be extracted by vacuum through orifices 29, Figure 8, of the outlet module 5, Figure 1. Upon reaching the end of the conveyor belt, the charcoal falls onto a system with two gate valves 30, Figure 8, which are never opened simultaneously. First, the first valve opens and the charcoal is discharged onto the second, closed valve. Then, the second valve closes and the second valve opens so that the charcoal falls into container 31, which will be taken outside the building to be cooled in the open air. This procedure ensures that no air enters the reactor when the charcoal is discharged, which could cause a strong explosion, since the internal atmosphere is full of gases heated to 400°C. eC with high calorific value. Due to the presence of such hot gases, even the slightest air intake could cause an internal explosion, momentarily raising the pressure to levels that could damage the equipment. Therefore, there is a safety valve 32 to relieve abrupt pressure increases resulting from explosions caused by human error.

[0042] Furthermore, to make the invention operationally viable, the gate valves installed in the outlet module have electrically heated bands. When the reactor is shut down for maintenance, they need to remain heated to prevent them from sticking due to the solidification of the tars contained in the pyrolysis smoke that deposit on the entire internal surface of the last reactor module. The same applies to safety valve 32 and to the valves installed at the smoke outlet before the exhaust fans.

[0043] The smoke produced continuously inside the reactor has a high energy density because no nitrogen has entered. It is extracted at the beginning of the outlet module 5, Figure 3, through orifices 29, Figure 9, by means of exhaust fans that create a slight depression. There are two gate valves installed upstream and downstream of the exhaust fans to allow for their maintenance. And there are always two because they operate under severe temperature and fouling (tar) conditions. This smoke exits the reactor at 400 e C and will be conducted through stainless steel pipes 33 to the two coolers 34. At this point, the condensables are separated, REPLACEMENT SHEET (RULE 26) The oil is stored in tank 35 and pumped to coolers 34 to aid in cooling, and part of it is directed to be emulsified with 4% ethanol in reactor 36. Pyrolysis oil is a two-phase fluid, and emulsification provides chemical stability for long-term storage. If the thermoelectric power generation unit is located on the same site as the coal reactors, this emulsification step is not necessary. The emulsified oil is directed to a storage tank 37, and the non-condensable gases go to a gasometer.

[0044] Figure 10 shows panels 38 and 39 where the process controllers, switching, control and protection devices are located. Power and industrial network cables that activate the microwave generator kits 26 (Figure 7) come out of panel 39. Each kit has an address on the control network and receives an identification to facilitate maintenance or component replacement. The use of the industrial network brings many benefits to the invention, as it gives it self-diagnostic capability, identifying and immediately communicating to the industrial plant supervisor, via cell phone messages, that a certain component has failed and needs to be replaced. Thus, the operational availability time of the equipment is increased to values ​​above 86%.

[0045] No equipment designed for use with microwaves in an enclosed environment can avoid a detailed study of microwave propagation. In this invention, the geometry of the cavities was developed with the aid of computational simulation resources to design a cavity that allows a homogeneous distribution of energy throughout all zones within the cavities, ensuring that each piece of wood receives the same amount. In Figure 11, simulation 40 can be compared with 41, and it can be observed that in 40 there are zones 42 with low energy density, while geometry 41 clearly shows a fairly uniform distribution with low energy reflection at the microwave valve antennas. Thus, the charcoal produced in region 42 will have completely different characteristics from the others.In addition to reducing electricity consumption, the simulation allows the control system to manage the temperature profile of each region to ensure the quality of the coal produced in terms of the aforementioned physical and chemical aspects. REPLACEMENT SHEET (RULE 26)

[0046] The reactor automation system consists of controlling analog variables, such as temperature and internal pressure in each module, conveyor speed, and exhaust fan rotation speed, and discrete variables such as: limit switches for the gate valves, sensors for the presence of materials in the inlet chamber of the first module, presence sensors along the conveyor belt, position of inspection and cleaning windows, presence or absence of the coal receiving vessel, status of magnetron valves, status of the safety valve, and many other sensors spread throughout the reactor to ensure interlocking between control variables and operational safety, preventing human operating errors. Interlocking refers to the momentary blocking between, for example, two control valves that cannot be open at the same time. Thus, if one is open, the other will be deactivated and cannot be opened.This blocking is ensured by a process logic controller assisted by position sensors installed on the valve pistons.

[0047] To support such a large number of sensors and actuators, an automation architecture similar to that shown in Figure 12 was used, where the presence of two computers is immediately noticeable. To guarantee the quality of the charcoal produced, a first computer 43 must execute a program that will calculate the temperature set-points in each reactor module based on the control objective, which can be twofold: controlling the reactor by choosing a specific gravimetric yield or by the fixed carbon content in the charcoal. For these calculations, the operator will need to provide the program with the following data: moisture content of the wood, average diameter, lignin content, cellulose content, and hemicellulose content of the wood to be processed.Thus, depending on what is desired to be produced, the program will generate temperature references for each module and send them to the supervisory system 44, which will forward them to the programmable logic controller 45, where: A = CPU; B = POWER SUPPLY; C and D = 32 Dl (24 Vdc); E and F = 32 DO (24 Vdc); G = MAINS (Inverters); H = 16 Al (4 to 20 mA); I = MODBUS MAINS.

[0048] The programmable logic controller has several cards or modules to support the different types of sensors and actuators used in the reactor. For the analog sensors, there are dedicated readout cards for these measured variables, such as temperatures. For the various analog actuators, REPLACEMENT SHEET (RULE 26) As a geared motor that drives the conveyor belt and others, a dedicated Modbus 46 control network is used for these types of devices, where: J = Conveyor belt; K = Exhaust fan 1; L = Exhaust fan 2; M = Burner 1; N = Burner 2; O = Box elevator. This network has several functions and allows diagnosing the health of each instrument connected to the industrial network. For the activation of the microwave emitter kits, another dedicated Modbus network is used with several multiplexers or remote units installed in each panel 39, Figure 10. In each module there are thirty-two wave emitter kits. In total, there are at least 360 kits activated individually or together. The activation method is determined by the control strategy programmed in the logic controller 45.Basically, the main functionalities of the automation system are: automatic registration of kits in operation in the supervisory system; automatic registration of kits with faults in the supervisory system, with fault identification; remote activation of kits, individually, in-line or in groups, via the supervisory system, through controllers installed in each kit; conveyor displacement control system (manual / automatic); billet feeding system (manual / automatic); coal discharge system (manual / automatic); carbonization gas exhaust system (manual / automatic); and interlocking between control variables and final control devices.

[0049] The logic controller 45 receives information from the sensors in the field, calculates the position of each final control element, and sends the command signals. All of this is monitored by the computer 44 through the supervisory and control system, Figure 13, where: I = “The power supply system is operating in mode. 1 'II = “The furnace is operating in mode:”; III = “The discharge system is operating in mode:”. Each control variable, for example, the temperature of the first sensor, is controlled separately from the others through a negative feedback regulatory control strategy. Although the process control works in isolation for each measured variable, they are interrelated to ensure coal quality and interlocked to prevent erroneous operations.

[0050] The monitoring and control system screen shown in Figure 13 allows the operator to have a panoramic view of the entire reactor or reactor complex. Everything is in real time, and operation can take place locally or anywhere in the world if there is an internet connection. Reference values ​​for the temperatures in each module are displayed at the bottom of screen 49 so that REPLACEMENT SHEET (RULE 26) The operator can compare it with the temperatures measured and indicated along the reactor 50. The difference between these indications is handled by the logic controller 45, Figure 12, which will act by switching the kits on or off so that the two indications are always as close as possible. Using graph 51, the operator can monitor the evolution of the variables controlled by the control system and intervene if any anomaly is noticed, switching the logic controller 45, Figure 12, to manual operation 52. From then on, the operator is responsible for activating or deactivating each final control element, whether kit, geared motor or others. It is necessary that the operator be well trained to safely conduct the process in manual mode, despite the safety interlock that is never deactivated.

[0051] Throughout the reactor's operation, any alarms that may occur will be displayed on screen 53, allowing the operator to recognize and resolve them. On screen 54, the operator will receive a series of reminders to assist in operating the system and taking various actions. Finally, in the navigation menu 55, the operator can change some system operating parameters, such as: alarms, graph adjustment, wood parameters and characteristics, the desired coal specification, and switch to other screens that show details of the wood feeder operation, gas outlet, and coal discharge. Each operator has a user code and password for identification. Every operation generates logs that are recorded and stored for thirty days. Thus, if necessary, all reactor operation information can be retrieved during a specific event.

[0052] Explosion detection is identified by calculating, in real time and constantly, the rate of change of each temperature from the various sensors. When the system detects a high rate or a sudden and rapid temperature rise of a few degrees, all equipment is instantly shut down and sirens sound, indicating an impending explosion. At this moment, the safety valve will break the seal and expel all gases from the explosion, relieving the pressure inside the reactor. The operator can then investigate the reason for the air ingress, whether due to a faulty actuator or open drain sensors. Once the problem is resolved, the reactor returns to normal operation. REPLACEMENT SHEET (RULE 26)

Claims

CLAIMS 1. CONTINUOUS PRODUCTION UNIT OF STEEL AND ENERGY CHARCOAL BY MICROWAVE-ASSISTED PYROLYSIS characterized by being a horizontal industrial pyrolysis reactor that works in an explosive atmosphere and with microwave-assisted modules, dedicated to the production of charcoal, pyrolysis oil and non-condensable gases, without pollutant emissions, with an advanced automatic process control system integrated with the world wide web.

2. UNIT FOR CONTINUOUS PRODUCTION OF STEEL CHARCOAL AND ENERGY BY MICROWAVE-ASSISTED PYROLYSIS, contains a metal conveyor belt dedicated to the transportation of wood logs according to claim 1, characterized by being constructed in various shapes and made of carbon steel.

3. CONTINUOUS PRODUCTION UNIT OF STEEL AND ENERGY COAL BY MICROWAVE-ASSISTED PYROLYSIS contains a microwave propagation cavity according to claims 1 and 2, characterized by being modular with a length multiple of 6 meters, width of 1.2 to 2.4 m, with a variable height, which may vary depending on the conveyor / drive assembly and with thermal insulation, protective cover and withstanding temperatures of up to 600 degrees Celsius.

4. UNIT FOR CONTINUOUS PRODUCTION OF STEEL AND ENERGY STEEL CHARCOAL BY MICROWAVE-ASSISTED PYROLYSIS contains microwave generator kits according to claims 1 and 3, characterized by having in metal boxes all the components necessary for microwave emission, as well as the waveguides and a cooling system for the components by forced ventilation or closed circuit with water or another refrigerant fluid.

5. UNIT FOR CONTINUOUS PRODUCTION OF STEEL AND ENERGY CHARCOAL BY MICROWAVE-ASSISTED PYROLYSIS has openings distributed along the cavities for the installation of microwave generator kits, according to claims 1, 3 and 4, arranged in lines and columns, with a power of 1 kW to 3 kW per kit, characterized by cavity insulation with quartz crystal windows and waveguide, and may have the quantity necessary to carry out pyrolysis, but not limited to these powers.

6. CONTINUOUS PRODUCTION UNIT FOR STEEL AND ENERGY CHARCOAL BY MICROWAVE-ASSISTED PYROLYSIS has a feeding system according to claims 1, 2 and 3, characterized by a compartmentalized device that allows the wood to be introduced manually or automatically into a first compartment where the air is extracted and then into a second compartment where it is pushed onto the conveyor belt.

7. UNIT FOR CONTINUOUS PRODUCTION OF STEEL AND CHARCOAL AND ENERGY BY MICROWAVE-ASSISTED PYROLYSIS has an automatic wood feeding system according to claims 1, 2, 3 and 6, characterized by an external device that organizes and directs the wood billets to the inlet of the reactor feeding system.

8. CONTINUOUS PRODUCTION UNIT OF STEEL AND ENERGY COAL BY MICROWAVE-ASSISTED PYROLYSIS has a billet compaction device according to claims 1, 2, 3 and 7, characterized by a set of plates pressed by springs arranged on the metal belt.

9. UNIT FOR CONTINUOUS PRODUCTION OF STEEL AND ENERGY COAL BY MICROWAVE-ASSISTED PYROLYSIS has a coal discharge device according to claims 1, 2 and 3, characterized by two guillotine valves in front to allow discharge without the entry of air into the cavity.

10. CONTINUOUS PRODUCTION UNIT OF STEEL AND ENERGY COAL BY MICROWAVE-ASSISTED PYROLYSIS has a safety valve according to claims 1 and 3, characterized by a tube of variable length with a movable cover that opens when there is an excessive increase in pressure in the cavity, avoiding material damage by relieving the pressure to the atmosphere.

11. CONTINUOUS PRODUCTION UNIT OF STEEL AND ENERGY COAL BY MICROWAVE-ASSISTED PYROLYSIS has an advanced control system according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 characterized by sensors distributed throughout the cavities, process computer, programmable logic controller, control software and supervision system for safe and remote operation of the unit through synoptic screens, graphs, buttons and event recorders.

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