WO2021119871A1 - System and method for improving the combustion process of a solid fuel by means of an inert porous medium - Google Patents

System and method for improving the combustion process of a solid fuel by means of an inert porous medium Download PDF

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Publication number
WO2021119871A1
WO2021119871A1 PCT/CL2020/050179 CL2020050179W WO2021119871A1 WO 2021119871 A1 WO2021119871 A1 WO 2021119871A1 CL 2020050179 W CL2020050179 W CL 2020050179W WO 2021119871 A1 WO2021119871 A1 WO 2021119871A1
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WO
WIPO (PCT)
Prior art keywords
combustion
inert porous
solid fuel
porous medium
hearth
Prior art date
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PCT/CL2020/050179
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Spanish (es)
French (fr)
Inventor
Mario Gonzalo TOLEDO TORRES
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Universidad Técnica Federico Santa María
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Application filed by Universidad Técnica Federico Santa María filed Critical Universidad Técnica Federico Santa María
Priority to CA3168332A priority Critical patent/CA3168332A1/en
Priority to PE2022001112A priority patent/PE20221616A1/en
Publication of WO2021119871A1 publication Critical patent/WO2021119871A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B60/00—Combustion apparatus in which the fuel burns essentially without moving
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B90/00—Combustion methods not related to a particular type of apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
    • F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M20/00—Details of combustion chambers, not otherwise provided for, e.g. means for storing heat from flames
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00—Stoves or ranges
    • F24B1/18—Stoves with open fires, e.g. fireplaces
    • F24B1/191—Component parts; Accessories
    • F24B1/197—Hearths

Definitions

  • the present invention refers to a system and method that comprise the use of an inert porous material arranged in the vicinity of a solid fuel, inside a combustion hearth, to improve the combustion process of said solid fuel.
  • solid fuels such as biomass, coal or others.
  • One of the ways that exist to improve the efficiency of the solid fuel combustion process is to maximize the delivery and utilization of the calorific value of said solid fuel (for example, from firewood).
  • the common approach to achieve this technical effect is to use equipment specially designed for combustion, operated according to methods appropriate to the type of fuel.
  • combustion hearths it is common to use heat-resistant materials and the implementation of appropriate designs for the hearth, which allow to reduce losses to the outside, maintaining a high and constant temperature inside the home.
  • patent document CL 2014-01778 uses a mixture of an inert porous medium (alumina spheres) with a solid fuel (biomass, coal or other) for the generation of synthesis gas.
  • alumina spheres alumina spheres
  • solid fuel biomass, coal or other
  • the invention relates to a combustion system and method to improve the efficiency of the solid fuel combustion process.
  • the solid fuel combustion system of the present invention comprises: a combustion hearth that contains solid fuel inside, wherein said solid fuel is subjected to a combustion process inside the combustion hearth; an inert porous medium arranged inside said hearth, wherein said inert porous medium is in the vicinity of the solid fuel; and flow control means arranged in the combustion hearth.
  • the flow control means are arranged to control the operation of at least one air inlet and at least one exhaust gas outlet, arranged in the fireplace.
  • the air inlet is designed or configured to inject intake air into the home.
  • the gas outlet is designed or configured to release unreacted combustion gases to the outside of the home, in the form of exhaust gases, where said combustion gases are generated by the combustion process that occurs inside the home.
  • the flow control means are designed or configured to generate a flow of intake air and combustion gases into the combustion hearth, between the at least one air inlet and the at least one exhaust gas outlet.
  • the flow of intake air and combustion gases forms a premix of intake air and combustion gases to the interior of the fireplace.
  • the flow control means and the inert porous medium are configured to circulate said premix through the inert porous medium.
  • the premix circulates through the pores of the inert porous medium, which causes the preheating of the intake air and the acceleration of the reaction of the combustion gases within said pores. With this, the circulating premix is combusted within the pores of the inert porous medium.
  • the present invention does not intend to describe with the usual components of solid fuel combustion systems, such as the intake air flow control means and combustion gases, or the use of double chambers and others. mechanisms currently implemented in different systems, such as the wood-burning stoves that exist today. Indeed, the elements described are those that have a direct participation in obtaining the advantages proposed by the invention, associated with the use of inert porous media in the combustion process.
  • the solid fuel combustion method of the present invention comprises the following stages: a) arranging solid fuel and arranging an inert porous medium inside a combustion hearth of a solid fuel combustion system, wherein the Inert porous medium is arranged in the vicinity of the solid fuel; b) injecting intake air into the combustion hearth, through at least one air inlet arranged in the combustion hearth, wherein the injection of said intake air is controlled by flow control means arranged in the combustion hearth; c) igniting the solid fuel, subjecting said solid fuel to a combustion process inside the combustion hearth; d) generating a flow of intake air and combustion gases between the at least one air inlet and at least one exhaust gas outlet also arranged in the combustion hearth, wherein said flow of intake air and combustion gases it is controlled by said flow control means, forming a premix of intake air and combustion gases inside the combustion hearth; e) circulating the premix through the inert porous medium, in particular, through the pores of said inert porous medium, to
  • the arrangement of the inert porous medium in the vicinity of the solid fuel allows establishing a thermal contact between said inert porous medium and said solid fuel, whereby thermal contact should be understood as the occurrence of heat transfer mechanisms between the inert porous medium and the fuel. solid.
  • the step of injecting intake air is controlled according to the amount of air desired for the combustion process, by controlling the at least one air inlet.
  • the amount of air desired for the combustion process can be selected according to the state of the combustion process inside the home, either by measuring the temperature inside the home and / or combustion gases towards the at least one outlet.
  • the amount of air that is injected into the home depends on the oxygen required for the chemical reactions involved in the combustion process, seeking to avoid imperfect combustion of solid fuel.
  • the stage of injecting intake air and / or the stage of releasing exhaust gases are controlled. according to the desired premix circulation through the inert porous medium, by controlling the at least one air inlet and the at least one exhaust gas outlet.
  • the circulation of the premix through the pores of the inert porous medium allows the combustion gases, generated as gases from the devolatilization of the solid fuel, to mix with the intake air, favoring the formation of the premix and its combustion inside the pores.
  • the step of arranging the solid fuel comprises arranging two or more solid units that form said solid fuel.
  • Solid units may or may not be of different dimensions and may or may not be randomly positioned inside the home.
  • solid fuel, and the solid units that form it are selected from biomass, coal or a combination of both.
  • biomass should be understood as: wood, in any of its presentations, for example, logs, pellets, sawdust, etc .; wheat residues, straw, nut shells, or other natural fibrous materials;
  • the present invention also considers different types of coal as solid fuel, independent of their humidity, amount of ash and / or calorific value.
  • Some types of coal are lignite, sub-bituminous coal, coal (fat, semi-fat and / or dry), bituminous coal, anthracite and coking coal, among others.
  • solid fuels that can also be used by the present invention, in addition to biomass and coal, can be peat, combustible waste or other natural or artificial solid fuels.
  • the step of arranging the inert porous medium inside the combustion hearth comprises placing at least one inert porous unit inside the combustion hearth. Said at least one inert porous unit forming the inert porous medium.
  • the inert porous medium within the combustion hearth comprises two or more inert porous units, said two or more inert porous units arranged inside the combustion hearth at different positions.
  • Preferred embodiments of the invention comprise placing the inert porous unit (s) in physical contact with the solid fuel, in positions that maximize and ensure said physical contact with the solid fuel.
  • the physical contact between the solid fuel and the inert porous medium which generates a thermo-physical contact, intensifies the transfer of heat, mainly by conduction, convection and radiation, and therefore the solid fuel manages to burn at a higher temperature and in a more efficient.
  • a first inert porous unit is positioned between the solid fuel and a side wall of the combustion hearth and a second inert porous unit is positioned between the solid fuel and another side wall. of the combustion hearth.
  • a combustion hearth having at least four walls, two side walls, a rear wall and a front wall, comprises inert porous units arranged at least between the solid fuel and the side walls of the hearth.
  • a third inert porous unit is positioned between the solid fuel and a rear wall of the combustion hearth. This lateral and rear location of the inert porous units reduces the emission of particulate material by 50%, considering the stove without inert porous medium as a point of comparison.
  • the front wall is also the access door to the interior of the hearth, usually comprising a glass. Then, the operation of the fourth inert porous unit arranged towards said front wall will be affected by the opening / closing operations of the access door to the hearth and / or by the greater heat transfer that occurs from said front wall to the outside. of home.
  • the position where the inert porous medium is placed in contact with the solid fuel should not only favor the generation of the premix and its combustion, as is achieved with the lateral and rear positions indicated above, but also it should favor an optimal cleaning of the ashes generated after the combustion process.
  • inert porous units towards the upper wall of the hearth, this has proven not to be as effective or functional compared to the dissipations towards the side and rear walls.
  • each inert porous unit can be formed by one or more inert porous elements, said elements usually presented in the form of discs with the appearance of sponges. porous.
  • the inert porous medium can be of a ceramic material, and can comprise a porosity of at least 50% and a pore density of at least 20 ppi.
  • a data acquisition unit for executing a step of acquiring operating data of the combustion system.
  • the present invention makes it possible to generate a combustion process with the active participation of the inert porous medium, which intensifies the heat transfer mechanisms (conduction, convection and radiation).
  • the active participation of the inert porous medium allows the air required for the combustion process to be preheated and the volatile combustion gases, a product of the devolatilization of solid fuel, to mix with the air and react rapidly inside the pores.
  • Figures 1a, 1b and 1c show right side, front, and left side views of a diagram representing the interior of the combustion hearth, according to an embodiment of the invention.
  • Figure 2 is a diagram of the wood burning process.
  • Figures 1 a, 1 b and 1 c show views of a representative diagram of the combustion hearth (10) according to an embodiment of the invention.
  • Figures 1 a and 1 c which show the right and left side views, respectively, allow to appreciate a schematic arrangement of the solid fuel (11) with respect to the inert porous medium (12) inside the combustion hearth (10).
  • the circulation of intake air and combustion gases (13) is schematized, including the formation of the premix (14) that circulates through the inert porous medium (12), for its combustion within the pores of said inert porous medium (12).
  • Figures 1 a and 1 c also show an inner plate (15) as a flow control means, in this case represented as a double chamber, which allows directing the flow of intake air and combustion gases towards an outlet (16), for the release of unreacted combustion gases, or exhaust gases (17).
  • an inner plate (15) as a flow control means, in this case represented as a double chamber, which allows directing the flow of intake air and combustion gases towards an outlet (16), for the release of unreacted combustion gases, or exhaust gases (17).
  • figure 1 b which shows the front view of the scheme of the combustion hearth (10), allows to identify how the solid fuel (12) is surrounded, by the inert porous medium (12), represented by lateral porous units first and second (12 ', 12 ”) and by a third subsequent inert porous unit (12"').
  • the present invention is implemented in a combustion system that uses wood as a solid fuel.
  • Firewood is not a homogeneous fuel, like oil or natural gas.
  • several reaction phases are identified in the wood combustion process:
  • the exterior surface of the wood receives heat by radiation from the flames, heating the water contained in the wood above its evaporation point. At this point the drying process begins, releasing moisture in the form of water vapor. This drying process consumes a significant fraction of the energy released in the combustion process. The higher the initial water content of the firewood, the more energy will be consumed in this drying process and the slower the first stage of heating the firewood becomes;
  • the solid carbon When the volatile matter is completely released from the wood, the solid carbon remains as a residual product together with the non-combustible ash.
  • This solid compound is equivalent to wood charcoal and is characterized by its superficial combustion with a red glow and a very small flame generating a high temperature between 600 and 1,000 [° C].
  • Coal is a clean fuel that burns easily with presence of sufficient oxygen without generating fumes, but nevertheless generating carbon monoxide (CO).
  • FIG. 1 shows a diagram of the three phases of wood combustion, occurring simultaneously.
  • a minimum residence time of the combustion gases inside the home must be guaranteed. For example, if temperatures are higher than 900 ° C, the minimum residence time must exceed 0.5 seconds.
  • a residential heater equivalent to that of the base test was arranged, and the solid fuel to be placed inside the combustion hearth of said heater was prepared, in a manner equivalent to the base test.
  • the useful volume of the hearth or combustion chamber of the heater tested does not exceed 0.02 m 3
  • 3 pieces of eucalyptus wood with a length of 0.25 m were dimensioned, with variable width to achieve the mass required for the test.
  • the useful volume of the combustion chamber based on a volumetric charge density of 112 ⁇ 11.2 kg / m 3 .
  • an inert porous medium made of Silicon Carbide (SiC) material was incorporated in the form of a disc with a diameter of 200 mm, a thickness of 30 mm and a porosity of 82.5%.
  • SiC Silicon Carbide
  • the heat delivered by the combustion of wood to the environment through the walls of the heater was notably higher when using the inert porous medium, reaching a maximum of approximately 1000 W, compared to the maximum of 500 W of the heater without inert porous medium, this using maximum air intake.
  • This is due to the increase in the average temperature of the combustion chamber when using inert porous medium, which causes a greater flow of heat by radiation and convection towards the environment.
  • the increase in the temperature of the heater walls is due to the heat transfer phenomenon present between the reaction of the air-fuel premix and the inert porous medium, which generates an increase in temperature of the inert porous medium as a result of the heat transferred. from the reaction of the air-fuel premix, achieving an increase in the temperature of the combustion hearth.
  • the configuration of test 2 exhibits a better performance with respect to the emission of CO compared to the configuration of test 1.
  • This difference is due to the configuration of the inert porous media in each test, inside the combustion chamber, since in test 2 said inert porous media covers a greater height of the hearth, also causing heat transfer by convection from the reaction of the air-fuel premix to the porous medium, whereby the combustion gases as they rise and come into contact with the ceramic semi-discs increase their temperature and are burned again by lowering the CO concentration.
  • the configuration of test 1 with the inert porous medium under the solid fuel, causes the pores to become saturated when the ash is produced during the combustion process, making it difficult for the air-fuel premix to circulate through said porous medium. inert.
  • the base test which does not use inert porous medium, has a thermal efficiency of 68.91%, while test 1 has a yield of 81.41% and test 2 has a yield of 91.04%. .
  • test 1 has a yield of 81.41%
  • test 2 has a yield of 91.04%.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Physics & Mathematics (AREA)
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Abstract

The invention relates to a solid fuel combustion system and method that use an inert porous medium in the combustion process. The system comprises: a combustion chamber containing solid fuel, the solid fuel being subjected to a combustion process inside the chamber, generating combustion gases; an inert porous medium disposed inside the combustion chamber, the porous medium being near the solid fuel; and flow control means disposed in the combustion chamber. The flow control means are disposed to control the operation of: at least one air inlet in the combustion chamber, for injecting intake air into the combustion chamber; and at least one exhaust gas outlet in the combustion chamber, for releasing exhaust gases from the combustion chamber. The flow control means generate a flow of intake air and combustion gases between the at least one air inlet and the at least one exhaust gas outlet, forming a premixture of intake air and combustion gases inside the chamber. The flow control means and inert porous medium circulate the premixture through the inert porous medium, particularly through the pores of the inert porous medium, causing the preheating of the intake air and the acceleration of the reaction of the combustion gases inside the pores, burning the premixture in the interior of the pores of the inert porous medium.

Description

SISTEMA Y MÉTODO PARA MEJORAR EL PROCESO DE COMBUSTIÓN DE UN COMBUSTIBLE SÓLIDO MEDIANTE MEDIO POROSO INERTE SYSTEM AND METHOD TO IMPROVE THE COMBUSTION PROCESS OF A SOLID FUEL THROUGH INERT POROUS MEDIA
La presente invención se refiere a un sistema y método que comprenden el uso de un material poroso inerte dispuesto en la cercanía de un combustible sólido, al interior de un hogar de combustión, para mejorar el proceso de combustión de dicho combustible sólido. The present invention refers to a system and method that comprise the use of an inert porous material arranged in the vicinity of a solid fuel, inside a combustion hearth, to improve the combustion process of said solid fuel.
Antecedentes Background
En la actualidad, uno de los combustibles más utilizados en sistemas de generación de calor, como estufas de calefacción u otro tipo de hornos, son los combustibles sólidos, como por ejemplo, biomasa, carbón u otros. At present, one of the most widely used fuels in heat generation systems, such as heating stoves or other types of furnaces, are solid fuels, such as biomass, coal or others.
Por lo general, el amplio uso de los combustibles sólidos como medio combustible al interior de un hogar de combustión, se debe a que ellos son usualmente más económicos que los combustibles líquidos o gaseosos. Sin embargo, la gran desventaja de los combustibles sólidos radica en la baja eficiencia del proceso de combustión, que resulta en una mayor emisión de gases de escape y material particulado contaminantes en comparación con el uso de combustibles líquidos o gaseosos. In general, the wide use of solid fuels as a fuel medium within a combustion hearth is due to the fact that they are usually cheaper than liquid or gaseous fuels. However, the great disadvantage of solid fuels lies in the low efficiency of the combustion process, which results in a higher emission of exhaust gases and polluting particulate matter compared to the use of liquid or gaseous fuels.
En este contexto, es común la necesidad de mejorar la eficiencia de los procesos de combustión para combustibles sólidos, que permitan reducir considerablemente la emisión de gases de escape y material particulado contaminantes contenientes en sistemas de combustión que empleen dicho tipo de combustibles. In this context, there is a common need to improve the efficiency of combustion processes for solid fuels, which make it possible to considerably reduce the emission of exhaust gases and contaminating particulate matter contained in combustion systems that use said type of fuels.
Una de las maneras que existen para mejorar la eficiencia del proceso de combustión de combustibles sólidos es maximizar la entrega y utilización del poder calorífico de dicho combustible sólido (por ejemplo, de la leña). La aproximación común para lograr dicho efecto técnico es utilizar equipos especialmente diseñados para la combustión, operados según métodos adecuados al tipo de combustible. Por ejemplo, en los hogares de combustión es común el uso de materiales resistentes al calor y la implementación de diseños apropiados para el hogar, que permitan reducir las pérdidas hacia el exterior, manteniendo una alta temperatura y constante al interior del hogar. One of the ways that exist to improve the efficiency of the solid fuel combustion process is to maximize the delivery and utilization of the calorific value of said solid fuel (for example, from firewood). The common approach to achieve this technical effect is to use equipment specially designed for combustion, operated according to methods appropriate to the type of fuel. For example, in combustion hearths it is common to use heat-resistant materials and the implementation of appropriate designs for the hearth, which allow to reduce losses to the outside, maintaining a high and constant temperature inside the home.
Entre los diseños de hogares más utilizados se encuentran la implementación de controles apropiados de entrada de aire, que a menudo aumentan le eficiencia del proceso de combustión. Además, los hogares modernos incorporan paredes metálicas en sus caras laterales y disponen de un espacio entre la carcasa del hogar y los muros colindantes donde este se encuentra, por ejemplo la cara posterior de una estufa a leña, lo que permite la libre circulación de aire entre la estufa y los muros colindantes. Among the most widely used fireplace designs are the implementation of appropriate air intake controls, which often increase the efficiency of the combustion process. In addition, modern hearths incorporate metal walls on their side faces and have a space between the housing of the hearth and the adjoining walls where it is located, for example the back face of a wood stove, which allows free air circulation. between the stove and the adjoining walls.
En el contexto de las estufas residenciales a leña, en el mercado existen diferentes tipos de estufas que utilizan leña como combustible, entre las cuales están: chimeneas, salamandras, estufas de combustión lenta y estufas de combustión lenta con doble cámara. Los diseños más utilizados comprenden una entrada de aire cerca del piso del inmueble, y una salida de aire cerca de la repisa de la estufa (ubicada en la parte superior de la puerta del hogar). Este diseño se traduce en una circulación convectiva de aire caliente, además del calor por radiación del hogar en sí. Sin embargo, la técnica de admisión de aire por la parte inferior del hogar, que da paso al ascenso de aire caliente a través del lecho del hogar, para luego escapar por los ductos de salida de la estufa, resulta ser ineficiente. En efecto, se ha descubierto que para calentar eficientemente, los gases combustibles liberados durante el proceso de combustión de la leña, o gases de combustión, deben ser mezclados con una gran cantidad de oxígeno a una temperatura mínima de 1100QC. Además, para una combustión completa de los gases combustibles liberados por la madera, se debe suministrar alrededor de un 80% más de la cantidad de aire necesitado para el combustible. In the context of residential wood-burning stoves, there are different types of stoves that use wood as fuel on the market, among which are: fireplaces, salamanders, slow-burning stoves and slow-burning dual-chamber stoves. The most commonly used designs include an air inlet near the floor of the building, and an air outlet near the stove top (located at the top of the fireplace door). This design results in a convective circulation of hot air, in addition to the radiation heat of the home itself. However, the air intake technique through the lower part of the hearth, which allows hot air to rise through the hearth bed, to then escape through the stove's outlet ducts, turns out to be inefficient. Indeed, it has been found that to heat efficiently combusting combustible gases released during the combustion of wood, or flue gas, they should be mixed with a large amount of oxygen at a temperature of 1100 Q C. In addition, for For a complete combustion of the combustible gases released by the wood, about 80% more than the amount of air needed for the fuel must be supplied.
En este contexto, la conveniencia de tener un suministro de aire por sobre el lecho del hogar, que permita calentar los gases combustibles liberados durante el proceso de combustión, ha llevado a diseñar equipos de calefacción de “aire descendente”. Tales equipos fuerzan la circulación de los gases combustibles a través de estructuras internas dispuestas como “laberintos”, donde son mezclados con una corriente de aire caliente, logrando una combustión prácticamente completa, reduciendo los contaminantes en los gases de escape. En los equipos menos eficientes, estos gases combustibles escapan por la chimenea en la forma de gases de escape, o se depositan en el ducto en forma de hollín y/o creosota. In this context, the convenience of having an air supply above the hearth bed, which allows heating the combustible gases released during the combustion process, has led to the design of "down-air" heating equipment. Such equipment forces the circulation of combustible gases through internal structures arranged as "labyrinths", where they are mixed with a stream of hot air, achieving practically complete combustion, reducing pollutants in the exhaust gases. In teams Less efficient, these combustible gases escape through the chimney in the form of exhaust gases, or are deposited in the duct in the form of soot and / or creosote.
En los últimos años el desarrollo de nuevas tecnologías para mejorar la eficiencia de la combustión ha logrado grandes avances, como en el caso de la aplicación de medios porosos inertes. Por ejemplo, el documento de patente CL 2014-01778 utiliza una mezcla de medio poroso inerte (esferas de alúmina) con un combustible sólido (biomasa, carbón u otro) para la generación de gas de síntesis. Sin embargo, dicho documento no se focaliza en mejorar la eficiencia del proceso de combustión ni en la producción de calor, sino que solo busca generar gas de síntesis a partir de la gasificación del propio combustible sólido. In recent years the development of new technologies to improve combustion efficiency has made great strides, as in the case of the application of inert porous media. For example, patent document CL 2014-01778 uses a mixture of an inert porous medium (alumina spheres) with a solid fuel (biomass, coal or other) for the generation of synthesis gas. However, said document does not focus on improving the efficiency of the combustion process or on the production of heat, but only seeks to generate synthesis gas from the gasification of the solid fuel itself.
Otra solución de combustión que emplea materiales inertes se describe en el documento de patente US 10401023 B2. Dicho documento se refiere a un quemador que comprende una cámara de combustión con un material poroso mejorado con una composición catalítica de perovskita que recubre los poros del material poroso, produciéndose una combustión estable de una mezcla de gas natural y aire. Si bien dicho documento se refiere al uso de materiales porosos para estabilizar la combustión, no se refiere a la producción de calor, sino que solo busca aumentar la superficie de contacto entre la composición catalítica y la mezcla de gas natural y aire, utilizando para ello los poros del material inerte. Por lo tanto, resulta necesario contar con un sistema y método de combustión para mejorar la eficiencia del proceso de combustión de combustibles sólidos, disminuyendo las emisiones contaminantes de dicho tipo de combustibles sólidos. Descripción de la invención Another combustion solution using inert materials is described in patent document US 10401023 B2. Said document refers to a burner that comprises a combustion chamber with a porous material enhanced with a perovskite catalytic composition that covers the pores of the porous material, producing a stable combustion of a mixture of natural gas and air. Although said document refers to the use of porous materials to stabilize combustion, it does not refer to the production of heat, but only seeks to increase the contact surface between the catalytic composition and the mixture of natural gas and air, using for this the pores of the inert material. Therefore, it is necessary to have a combustion system and method to improve the efficiency of the solid fuel combustion process, reducing the polluting emissions of said type of solid fuels. Description of the invention
La invención se refiere a un sistema y método de combustión para mejorar la eficiencia del proceso de combustión de combustibles sólidos. The invention relates to a combustion system and method to improve the efficiency of the solid fuel combustion process.
En particular, el sistema de combustión de combustibles sólidos de la presente invención comprende: un hogar de combustión que contiene combustible sólido en su interior, en donde dicho combustible sólido es sometido a un proceso de combustión al interior del hogar de combustión; un medio poroso inerte dispuesto al interior de dicho hogar, en donde dicho medio poroso inerte está en la cercanía del combustible sólido; y medios de control de flujo dispuestos en el hogar de combustión. In particular, the solid fuel combustion system of the present invention comprises: a combustion hearth that contains solid fuel inside, wherein said solid fuel is subjected to a combustion process inside the combustion hearth; an inert porous medium arranged inside said hearth, wherein said inert porous medium is in the vicinity of the solid fuel; and flow control means arranged in the combustion hearth.
Los medios de control de flujo se disponen para controlar la operación de al menos una entrada de aire y al menos una salida de gases de escape, dispuestas en el hogar. La entrada de aire está diseñada o configurada para inyectar aire de admisión hacia el interior del hogar. La salida de gases está diseñada o configurada para liberar gases de combustión no reaccionados hacia el exterior del hogar, en la forma de gases de escape, en donde dichos gases de combustión se generan por el proceso de combustión que ocurre al interior del hogar. The flow control means are arranged to control the operation of at least one air inlet and at least one exhaust gas outlet, arranged in the fireplace. The air inlet is designed or configured to inject intake air into the home. The gas outlet is designed or configured to release unreacted combustion gases to the outside of the home, in the form of exhaust gases, where said combustion gases are generated by the combustion process that occurs inside the home.
Los medios de control de flujo están diseñados o configurados para generar un flujo de aire de admisión y gases de combustión al interior del hogar de combustión, entre la al menos una entrada de aire y la al menos una salida de gases de escape. El flujo de aire de admisión y gases de combustión forma una premezcla de aire de admisión y gases de combustión al interior del hogar. Adicionalmente, los medios de control de flujo y el medio poroso inerte están configurados para hacer circular dicha premezcla a través del medio poroso inerte. En particular, la premezcla circula a través de los poros del medio poroso inerte, lo que provoca el precalentamiento del aire de admisión y la aceleración de la reacción de los gases de combustión dentro de dichos poros. Con ello, la premezcla circulante se combustiona al interior de los poros del medio poroso inerte. The flow control means are designed or configured to generate a flow of intake air and combustion gases into the combustion hearth, between the at least one air inlet and the at least one exhaust gas outlet. The flow of intake air and combustion gases forms a premix of intake air and combustion gases to the interior of the fireplace. Additionally, the flow control means and the inert porous medium are configured to circulate said premix through the inert porous medium. In particular, the premix circulates through the pores of the inert porous medium, which causes the preheating of the intake air and the acceleration of the reaction of the combustion gases within said pores. With this, the circulating premix is combusted within the pores of the inert porous medium.
En este punto es importante destacar que la presente invención no pretende describir con los componentes usuales de los sistemas de combustión de combustibles sólidos, como los medios de control de flujo de aire de admisión y gases de combustión, o el uso de doble cámaras y otros mecanismos actualmente implementados en distintos sistemas, como las estufas a leña que existen en la actualidad. En efecto, los elementos descritos son aquellos que tienen una directa participación en la obtención de las ventajas que propone la invención, asociadas al uso de medios porosos inertes en el proceso de combustión. At this point it is important to note that the present invention does not intend to describe with the usual components of solid fuel combustion systems, such as the intake air flow control means and combustion gases, or the use of double chambers and others. mechanisms currently implemented in different systems, such as the wood-burning stoves that exist today. Indeed, the elements described are those that have a direct participation in obtaining the advantages proposed by the invention, associated with the use of inert porous media in the combustion process.
Por otra parte, el método de combustión de combustibles sólidos de la presente invención comprende las siguientes etapas: a) disponer combustible sólido y disponer un medio poroso inerte al interior de un hogar de combustión de un sistema de combustión de combustibles sólidos, en donde el medio poroso inerte se dispone en la cercanía del combustible sólido; b) inyectar aire de admisión hacia el interior del hogar de combustión, a través de al menos una entrada de aire dispuesta en el hogar de combustión, en donde la inyección de dicho aire de admisión es controlada por medios de control de flujo dispuestos en el hogar de combustión; c) encender el combustible sólido, sometiendo dicho combustible sólido a un proceso de combustión al interior del hogar de combustión; d) generar un flujo de aire de admisión y gases de combustión entre la al menos una entrada de aire y al menos una salida de gases de escape también dispuesta en el hogar de combustión, en donde dicho flujo de aire de admisión y gases de combustión es controlado por dichos medios de control de flujo, formándose una premezcla de aire de admisión y gases de combustión al interior del hogar de combustión; e) hacer circular la premezcla a través del medio poroso inerte, en particular, a través de los poros de dicho medio poroso inerte, para precalentar el aire de admisión y acelerar la reacción de los gases de combustión dentro de dichos poros, en donde la circulación de la premezcla es controlada por dichos medios de control de flujo y dicho medio poroso inerte, y en donde dicha premezcla se combustiona al interior de los poros del medio poroso inerte; y f) liberar gases de combustión no reaccionados hacia el exterior del hogar de combustión, en la forma de gases de escape, en donde la liberación de dichos gases de escape es controlada por dichos medios de control de flujo. On the other hand, the solid fuel combustion method of the present invention comprises the following stages: a) arranging solid fuel and arranging an inert porous medium inside a combustion hearth of a solid fuel combustion system, wherein the Inert porous medium is arranged in the vicinity of the solid fuel; b) injecting intake air into the combustion hearth, through at least one air inlet arranged in the combustion hearth, wherein the injection of said intake air is controlled by flow control means arranged in the combustion hearth; c) igniting the solid fuel, subjecting said solid fuel to a combustion process inside the combustion hearth; d) generating a flow of intake air and combustion gases between the at least one air inlet and at least one exhaust gas outlet also arranged in the combustion hearth, wherein said flow of intake air and combustion gases it is controlled by said flow control means, forming a premix of intake air and combustion gases inside the combustion hearth; e) circulating the premix through the inert porous medium, in particular, through the pores of said inert porous medium, to preheat the intake air and accelerate the reaction of the combustion gases within said pores, where the circulation of the premix is controlled by said flow control means and said inert porous medium, and wherein said premix is combusted within the pores of the inert porous medium; and f) releasing unreacted combustion gases to the outside of the combustion hearth, in the form of exhaust gases, where the release of said exhaust gases is controlled by said flow control means.
La disposición del medio poroso inerte en la cercanía del combustible sólido permite establecer un contacto térmico entre dicho medio poroso inerte y dicho combustible sólido, en donde por contacto térmico debe entenderse la ocurrencia de mecanismos de transferencia de calor entre el medio poroso inerte y el combustible sólido. The arrangement of the inert porous medium in the vicinity of the solid fuel allows establishing a thermal contact between said inert porous medium and said solid fuel, whereby thermal contact should be understood as the occurrence of heat transfer mechanisms between the inert porous medium and the fuel. solid.
De acuerdo con una modalidad de la invención, la etapa de inyectar aire de admisión es controlada según la cantidad de aire deseada para el proceso de combustión, mediante el control de la al menos una entrada de aire. La cantidad de aire deseada para el proceso de combustión puede ser seleccionada de acuerdo a el estado del proceso de combustión al interior del hogar, ya sea mediante mediciones de temperatura al interior del hogar y/o gases de combustión hacia la al menos una salida. Preferentemente, la cantidad de aire que se inyecta al hogar depende del oxígeno requerido para las reacciones químicas involucradas en el proceso de combustión, buscando evitar la combustión imperfecta del combustible sólido. According to one embodiment of the invention, the step of injecting intake air is controlled according to the amount of air desired for the combustion process, by controlling the at least one air inlet. The amount of air desired for the combustion process can be selected according to the state of the combustion process inside the home, either by measuring the temperature inside the home and / or combustion gases towards the at least one outlet. Preferably, the amount of air that is injected into the home depends on the oxygen required for the chemical reactions involved in the combustion process, seeking to avoid imperfect combustion of solid fuel.
Sin perjuicio de lo anterior, y en el entendido que el proceso de combustión usualmente implica una combustión imperfecta, evitando el exceso de aire que genera pérdidas calóricas, la etapa de inyectar aire de admisión y/o la etapa de liberar gases de escape son controladas según la circulación de premezcla deseada a través del medio poroso inerte, mediante el control de la al menos una entrada de aire y de la al menos una salida de gases de escape. En este sentido, la circulación de la premezcla a través de los poros del medio poroso inerte permite que los gases de combustión, generados como gases de la desvolatilización del combustible sólido, se mezclen con el aire de admisión, favoreciendo la formación de la premezcla y su combustión en el interior de los poros. Notwithstanding the foregoing, and with the understanding that the combustion process usually involves imperfect combustion, avoiding excess air that generates heat losses, the stage of injecting intake air and / or the stage of releasing exhaust gases are controlled. according to the desired premix circulation through the inert porous medium, by controlling the at least one air inlet and the at least one exhaust gas outlet. In this sense, the circulation of the premix through the pores of the inert porous medium allows the combustion gases, generated as gases from the devolatilization of the solid fuel, to mix with the intake air, favoring the formation of the premix and its combustion inside the pores.
De acuerdo con una modalidad de la invención, la etapa de disponer el combustible sólido comprende disponer dos o más unidades sólidas que forman dicho combustible sólido. Las unidades sólidas pueden o no ser de diferentes dimensiones y pueden o no ser posicionadas de forma aleatoria al interior del hogar. De acuerdo con las distintas modalidades de la invención, el combustible sólido, y las unidades sólidas que lo forman, se seleccionan entre biomasa, carbón o una combinación de ambos. A modo de ejemplo, por biomasa debe entenderse: madera, en cualquiera de sus presentaciones, por ejemplo, leños, pellets, aserrín, etc.; residuos de trigo, paja, cáscaras de nueces, u otros materiales fibrosos naturales; According to an embodiment of the invention, the step of arranging the solid fuel comprises arranging two or more solid units that form said solid fuel. Solid units may or may not be of different dimensions and may or may not be randomly positioned inside the home. According to the different embodiments of the invention, solid fuel, and the solid units that form it are selected from biomass, coal or a combination of both. By way of example, biomass should be understood as: wood, in any of its presentations, for example, logs, pellets, sawdust, etc .; wheat residues, straw, nut shells, or other natural fibrous materials;
Además, la presente invención también considera como combustible sólido distintos tipos de carbón, independiente de su humedad, cantidad de ceniza y/o poder calorífico. Algunos tipos de carbón son el lignito, carbón sub-bituminoso, la hulla (grasa, semigrasa y/o seca), el carbón bituminoso, la antracita y el carbón coque, entre otros. Furthermore, the present invention also considers different types of coal as solid fuel, independent of their humidity, amount of ash and / or calorific value. Some types of coal are lignite, sub-bituminous coal, coal (fat, semi-fat and / or dry), bituminous coal, anthracite and coking coal, among others.
Otros combustibles sólidos que también pueden ser utilizados mediante la presente invención, además de la biomasa y el carbón, pueden ser la turba, desechos combustibles u otros combustibles sólidos naturales o artificiales. Other solid fuels that can also be used by the present invention, in addition to biomass and coal, can be peat, combustible waste or other natural or artificial solid fuels.
De acuerdo con una modalidad de la invención, la etapa de disponer el medio poroso inerte al interior del hogar de combustión comprende disponer al menos una unidad porosa inerte al interior del hogar de combustión. Dicha al menos una unidad porosa inerte formando el medio poroso inerte. Alternativamente, el medio poroso inerte al interior del hogar de combustión comprende dos o más unidades porosas inertes, dichas dos o más unidades porosas inertes dispuestas al interior del hogar de combustión en diferentes posiciones. Modalidades preferentes de la invención comprenden disponer la o las unidades porosas inertes en contacto físico con el combustible sólido, en posiciones que maximicen y aseguren dicho contacto físico con el combustible sólido. El contacto físico entre el combustible sólido y el medio poroso inerte, que genera un contacto termo-físico, intensifica la transferencia de calor, por conducción principalmente, convección y radiación, y por ende el combustible sólido logra combustionarse a una mayor temperatura y de manera más eficiente. According to one embodiment of the invention, the step of arranging the inert porous medium inside the combustion hearth comprises placing at least one inert porous unit inside the combustion hearth. Said at least one inert porous unit forming the inert porous medium. Alternatively, the inert porous medium within the combustion hearth comprises two or more inert porous units, said two or more inert porous units arranged inside the combustion hearth at different positions. Preferred embodiments of the invention comprise placing the inert porous unit (s) in physical contact with the solid fuel, in positions that maximize and ensure said physical contact with the solid fuel. The physical contact between the solid fuel and the inert porous medium, which generates a thermo-physical contact, intensifies the transfer of heat, mainly by conduction, convection and radiation, and therefore the solid fuel manages to burn at a higher temperature and in a more efficient.
A modo de ejemplo, una primera unidad porosa inerte se posiciona entre el combustible sólido y una pared lateral del hogar de combustión y una segunda unidad porosa inerte se posiciona entre el combustible sólido y otra pared lateral del hogar de combustión. De este modo, un hogar de combustión que tiene al menos cuatro paredes, dos paredes laterales, una pared posterior y una pared frontal, comprende unidades porosas inertes dispuestas al menos entre el combustible sólido y las paredes laterales del hogar. Alternativamente, una tercera unidad porosa inerte se posiciona entre el combustible sólido y una pared posterior del hogar de combustión. Esta ubicación lateral y posterior de las unidades porosas inertes permite disminuir la emisión de material particulado en un 50%, considerando la estufa sin medio poroso inerte como punto de comparación. By way of example, a first inert porous unit is positioned between the solid fuel and a side wall of the combustion hearth and a second inert porous unit is positioned between the solid fuel and another side wall. of the combustion hearth. Thus, a combustion hearth having at least four walls, two side walls, a rear wall and a front wall, comprises inert porous units arranged at least between the solid fuel and the side walls of the hearth. Alternatively, a third inert porous unit is positioned between the solid fuel and a rear wall of the combustion hearth. This lateral and rear location of the inert porous units reduces the emission of particulate material by 50%, considering the stove without inert porous medium as a point of comparison.
Si bien es posible agregar una cuarta unidad porosa inerte dispuesta entre el combustible sólido y la pared frontal del hogar, en los sistemas de combustión convencionales la pared frontal es también la puerta de acceso al interior del hogar, comprendiendo usualmente un cristal. Luego, el funcionamiento de la cuarta unidad porosa inerte dispuesta hacia dicha pared frontal se verá afectado por las operaciones de apertura/cierre de la puerta de acceso al hogar y/o por la mayor transferencia de calor que ocurre desde dicha pared frontal hacia el exterior del hogar. Although it is possible to add a fourth inert porous unit arranged between the solid fuel and the front wall of the hearth, in conventional combustion systems the front wall is also the access door to the interior of the hearth, usually comprising a glass. Then, the operation of the fourth inert porous unit arranged towards said front wall will be affected by the opening / closing operations of the access door to the hearth and / or by the greater heat transfer that occurs from said front wall to the outside. of home.
En este contexto, la posición donde se coloca el medio poroso inerte en contacto con el combustible sólido no solo debe favorecer la generación de la premezcla y la combustión de la misma, como se logra con las posiciones laterales y posterior indicadas anteriormente, sino que también debe favorecer una limpieza óptima de las cenizas generadas posterior al proceso de combustión. Al respecto, si bien es también posible ubicar unidades porosas inertes hacia la pared superior del hogar, ello ha mostrado no ser tan efectivo ni funcional en comparación con las disipaciones hacia las paredes laterales y posterior. Por otra parte, respecto de la pared inferior del hogar, si bien es posible mejorar el proceso de combustión al usar dicha ubicación para unidades porosas inertes, ubicar una o más unidades porosas inertes bajo el combustible sólido impide una limpieza óptima de cenizas, saturándose los poros del medio poroso inerte con dicha ceniza y perdiéndose rápidamente las ventajas de usar el medio poroso inerte al interior del hogar. In this context, the position where the inert porous medium is placed in contact with the solid fuel should not only favor the generation of the premix and its combustion, as is achieved with the lateral and rear positions indicated above, but also it should favor an optimal cleaning of the ashes generated after the combustion process. In this regard, although it is also possible to locate inert porous units towards the upper wall of the hearth, this has proven not to be as effective or functional compared to the dissipations towards the side and rear walls. On the other hand, regarding the lower wall of the hearth, although it is possible to improve the combustion process by using said location for inert porous units, placing one or more inert porous units under the solid fuel prevents optimal ash cleaning, saturating the pores of the inert porous medium with said ash and rapidly losing the advantages of using the inert porous medium inside the home.
En este punto es relevante destacar que cada unidad porosa inerte puede estar formada por uno o más elementos porosos inertes, dichos elementos usualmente presentados en la forma de discos con la apariencia de esponjas porosas. En este sentido, el medio poroso inerte puede ser de un material cerámico, y puede comprender una porosidad de al menos el 50% y una densidad de poros de al menos 20 ppi. At this point it is relevant to highlight that each inert porous unit can be formed by one or more inert porous elements, said elements usually presented in the form of discs with the appearance of sponges. porous. In this sense, the inert porous medium can be of a ceramic material, and can comprise a porosity of at least 50% and a pore density of at least 20 ppi.
De acuerdo con una modalidad de la invención, se proporciona una unidad de adquisición de datos, para ejecutar una etapa de adquirir datos de operación del sistema de combustión. According to an embodiment of the invention, a data acquisition unit is provided, for executing a step of acquiring operating data of the combustion system.
En este contexto, la presente invención permite generar un proceso de combustión con la activa participación del medio poroso inerte, lo que intensifica los mecanismos de transferencia de calor (conducción, convección y radiación). Además, la activa participación del medio poroso inerte permite precalentar el aire requerido para el proceso de combustión y que los gases de combustión volátiles, producto de la desvolatilización del combustible sólido, se mezclen con el aire y reaccionen rápidamente al interior de los poros. In this context, the present invention makes it possible to generate a combustion process with the active participation of the inert porous medium, which intensifies the heat transfer mechanisms (conduction, convection and radiation). In addition, the active participation of the inert porous medium allows the air required for the combustion process to be preheated and the volatile combustion gases, a product of the devolatilization of solid fuel, to mix with the air and react rapidly inside the pores.
Breve descripción de las figuras Brief description of the figures
Como parte de la presente invención se presentan las siguientes figuras representativas de la misma, las que enseñan configuraciones preferentes de la invención y, por lo tanto, no deben considerarse como limitantes a la definición de la materia reivindicada. As part of the present invention, the following representative figures of the same are presented, which teach preferred configurations of the invention and, therefore, should not be considered as limiting the definition of the claimed matter.
Las figuras 1a, 1 b y 1 c muestras vistas lateral derecha, frontal, y lateral izquierda de un esquema que representa el interior del hogar de combustión, de acuerdo con una modalidad de la invención. Figures 1a, 1b and 1c show right side, front, and left side views of a diagram representing the interior of the combustion hearth, according to an embodiment of the invention.
La figura 2 es un esquema del proceso de combustión de la madera. Figure 2 is a diagram of the wood burning process.
Descripción detallada de las figuras Detailed description of the figures
Las figuras 1 a, 1 b y 1 c muestran vistas de un esquema representativo del hogar de combustión (10) de acuerdo con una modalidad de la invención. Las figuras 1 a y 1 c, que muestran las vistas laterales derecha e izquierda, respectivamente, permiten apreciar una disposición esquemática del combustible sólido (11 ) respecto del medio poroso inerte (12) al interior del hogar de combustión (10). Además, en dichas figuras se esquematiza la circulación de aire de admisión y gases de combustión (13), incluyendo la formación de la premezcla (14) que circula a través del medio poroso inerte (12), para su combustión dentro de los poros de dicho medio poroso inerte (12). Figures 1 a, 1 b and 1 c show views of a representative diagram of the combustion hearth (10) according to an embodiment of the invention. Figures 1 a and 1 c, which show the right and left side views, respectively, allow to appreciate a schematic arrangement of the solid fuel (11) with respect to the inert porous medium (12) inside the combustion hearth (10). In addition, in said figures the circulation of intake air and combustion gases (13) is schematized, including the formation of the premix (14) that circulates through the inert porous medium (12), for its combustion within the pores of said inert porous medium (12).
Por otra parte, las figuras 1 a y 1 c muestran también una placa interior (15) como medio de control de flujo, en este caso representado como una doble cámara, que permite dirigir la circulación del flujo de aire de admisión y gases de combustión hacia una salida (16), para la liberación de los gases de combustión no reaccionados, o gases de escape (17). On the other hand, Figures 1 a and 1 c also show an inner plate (15) as a flow control means, in this case represented as a double chamber, which allows directing the flow of intake air and combustion gases towards an outlet (16), for the release of unreacted combustion gases, or exhaust gases (17).
Por otra parte, la figura 1 b, que muestra la vista frontal del esquema del hogar de combustión (10), permite identificar cómo el combustible sólido (12) es rodeado, por el medio poroso inerte (12), representado por unidades porosas laterales primera y segunda (12', 12") y por una tercera unidad porosa inerte posterior (12"'). On the other hand, figure 1 b, which shows the front view of the scheme of the combustion hearth (10), allows to identify how the solid fuel (12) is surrounded, by the inert porous medium (12), represented by lateral porous units first and second (12 ', 12 ") and by a third subsequent inert porous unit (12"').
Debe entenderse que las figuras anteriores son esquemas representativos del hogar de combustión, buscando facilitar la visualización de los componentes del sistema de combustión que se reclama, y no mostrar una modalidad preferente de la disposición o diseño de dichos componentes. It should be understood that the previous figures are representative diagrams of the combustion hearth, seeking to facilitate the visualization of the components of the combustion system that is claimed, and not to show a preferred modality of the arrangement or design of said components.
Ejemplo de aplicación Application example
A modo de ejemplo, se implementa la presente invención en un sistema de combustión que utiliza leña como combustible sólido. La leña no es un combustible homogéneo, como el petróleo o gas natural. En comparación a combustibles líquidos y gaseosos, en el proceso de combustión de la madera se identifican varias fases de reacción: By way of example, the present invention is implemented in a combustion system that uses wood as a solid fuel. Firewood is not a homogeneous fuel, like oil or natural gas. Compared to liquid and gaseous fuels, several reaction phases are identified in the wood combustion process:
Secado de la madera: Wood drying:
Inicialmente la superficie exterior de leña recibe calor por radiación de las llamas, calentando el agua contenida en la madera por sobre su punto de evaporación. En este momento se inicia el proceso de secado, liberando la humedad en forma de vapor de agua. Este proceso de secado consume una fracción importante de la energía liberada en el proceso de combustión. Mientras mayor sea el contenido de agua inicial de la leña, una mayor cantidad de energía se consumirá en este proceso de secado y más lento se torna la primera etapa de calentamiento de la leña; Initially, the exterior surface of the wood receives heat by radiation from the flames, heating the water contained in the wood above its evaporation point. At this point the drying process begins, releasing moisture in the form of water vapor. This drying process consumes a significant fraction of the energy released in the combustion process. The higher the initial water content of the firewood, the more energy will be consumed in this drying process and the slower the first stage of heating the firewood becomes;
Gasificación y oxidación del material volátil: Gasification and oxidation of volatile material:
Al calentarse la madera seca por encima del punto de ebullición del agua, se inicia la segunda fase de pirólisis con la liberación de la materia volátil o desvolatilización. En esta etapa, la leña comienza a humear. El humo es el resultado visible de la descomposición térmica de la madera y se compone principalmente de una nube de gotitas combustibles de gases e hidrocarburos (alquitrán). Éstos se oxidan sólo bajo altas temperaturas y si además existe presencia de suficiente oxígeno. Este proceso de combustión con liberación de calor produce llamas largas y brillantes, que son características de la combustión de la leña seca.As dry wood is heated above the boiling point of water, the second phase of pyrolysis begins with the release of volatile matter or devolatilization. At this stage, the firewood begins to smoke. Smoke is the visible result of the thermal decomposition of wood and consists mainly of a cloud of combustible gas and hydrocarbon droplets (tar). These oxidize only under high temperatures and if there is also the presence of sufficient oxygen. This heat-releasing combustion process produces long, bright flames, which are characteristic of dry wood burning.
Si la materia volátil no se quema por completo al interior del fogón, se emitirán gases no quemados o gases de combustión, que condensarán sobre las paredes frías de los ductos de evacuación, formando los depósitos de creosota. También estos compuestos no quemados serán emitidos posteriormente como humo de color visible con una fuerte contaminación atmosférica en el área. El humo también representa una pérdida de eficiencia, porque contiene una gran parte de la energía presente en la madera. If the volatile matter is not completely burned inside the stove, unburned gases or combustion gases will be emitted, which will condense on the cold walls of the evacuation ducts, forming creosote deposits. Also these unburned compounds will be emitted later as visible colored smoke with strong air pollution in the area. Smoke also represents a loss of efficiency, because it contains a large part of the energy present in wood.
Quemado del carbón residual: Burning of residual coal:
Al liberarse completamente la materia volátil de la madera, permanece como producto residual el carbón sólido junto a la ceniza no combustible. Este compuesto sólido equivale al carbón de madera y se caracteriza por su combustión superficial con un resplandor rojo y llama muy pequeña generando una alta temperatura entre 600 y 1.000 [°C]. El carbón es un combustible limpio que se quema fácilmente con presencia de suficiente oxígeno sin generar humos, pero que sin embargo, genera monóxido de carbono (CO). When the volatile matter is completely released from the wood, the solid carbon remains as a residual product together with the non-combustible ash. This solid compound is equivalent to wood charcoal and is characterized by its superficial combustion with a red glow and a very small flame generating a high temperature between 600 and 1,000 [° C]. Coal is a clean fuel that burns easily with presence of sufficient oxygen without generating fumes, but nevertheless generating carbon monoxide (CO).
En la práctica, las tres fases de combustión de madera anteriormente descritas ocurren simultáneamente. Esto significa que los gases de la materia volátil pueden estar quemándose con largas llamas mientras que sobre la superficie del combustible el carbón se quema con el característico resplandor rojo y el agua en el centro de la leña se evapora lentamente. En la figura 2 se muestra un esquema de las tres fases de la combustión de la madera, ocurriendo simultáneamente. In practice, the three phases of wood combustion described above occur simultaneously. This means that the gases of the volatile matter may be burning with long flames while on the surface of the fuel the coal burns with the characteristic red glow and the water in the center of the firewood slowly evaporates. Figure 2 shows a diagram of the three phases of wood combustion, occurring simultaneously.
Para lograr una combustión completa de los productos de la descomposición térmica de la madera se requieren las siguientes condiciones, que se resumen en la regla “3T's” conocida en el campo técnico de la combustión. To achieve a complete combustion of the products of the thermal decomposition of wood, the following conditions are required, which are summarized in the rule "3T's" known in the technical field of combustion.
- Temperatura: La temperatura mínima que se requiere mantener al interior de un hogar para garantizar la combustión completa de los productos gaseosos debe ser lo más alta posible. En la literatura se indican valores promedios en la zona de combustión de mínimo 800 °C a máximo 1 .000 °C. - Temperature: The minimum temperature that is required to be maintained inside a home to guarantee the complete combustion of gaseous products must be as high as possible. The literature indicates average values in the combustion zone from a minimum of 800 ° C to a maximum of 1,000 ° C.
- Tiempo: Para lograr una combustión completa se debe garantizar un tiempo mínimo de residencia de los gases de combustión al interior del hogar. Por ejemplo, si se presentan temperaturas mayores a 900 °C, el tiempo de residencia mínimo debe superar los 0,5 segundos. - Time: To achieve complete combustion, a minimum residence time of the combustion gases inside the home must be guaranteed. For example, if temperatures are higher than 900 ° C, the minimum residence time must exceed 0.5 seconds.
- Turbulencia: La última condición necesaria para asegurar una combustión óptima se relaciona con una intensa turbulencia requerida para mezclar el oxígeno con la materia volátil en combustión. Para intensificar este proceso de mezcla se acostumbra inyectar aire secundario precalentado directamente en la zona de combustión por encima de la cama de combustible. - Turbulence: The last condition necessary to ensure optimal combustion is related to the intense turbulence required to mix the oxygen with the burning volatile matter. To intensify this mixing process, it is customary to inject preheated secondary air directly into the combustion zone above the fuel bed.
Solamente si se cumple con estas tres reglas básicas de temperatura mínima, tiempo de residencia mínimo y alta turbulencia se puede generar las condiciones para realizar una combustión óptima de la leña con la mínima emisión de contaminantes. El desafío de un diseño óptimo de una estufa o una cocina es conjugar estas tres condiciones básicas permitiendo garantizar siempre una combustión completa, minimizando las emisiones de contaminantes. En especial se deberá considerar las características de humedad, densidad, tamaño y especie de madera para dimensionar correctamente el volumen y forma de la cámara de combustión. Sólo de esta forma se podrán lograr altas eficiencias y gases de escape limpios sin la presencia de humos visibles. Luego, con la aplicación del medio poroso inerte dentro de la estufa, se aumenta la temperatura del hogar de combustión, lo que produce una mejora en la combustión de la madera. Only if these three basic rules of minimum temperature, minimum residence time and high turbulence are complied with, can the conditions be generated for optimal firewood combustion with the minimum emission of pollutants. The challenge of an optimal design of a stove or a kitchen is to combine these three basic conditions allowing to always guarantee a complete combustion, minimizing pollutant emissions. In particular, the characteristics of humidity, density, size and species of wood must be considered to correctly size the volume and shape of the combustion chamber. Only in this way can high efficiencies and clean exhaust gases be achieved without the presence of visible fumes. Then, with the application of the inert porous medium inside the stove, the temperature of the combustion hearth is increased, which produces an improvement in the combustion of the wood.
En función de lo anterior, y teniendo como ensayo base el proceso de combustión de leña sin medio poroso inerte, se procede a realizar dos ensayos de configuraciones de medios porosos inertes en el interior de un mismo hogar de combustión. Based on the foregoing, and having as a base test the wood burning process without inert porous medium, two tests of inert porous medium configurations are carried out inside the same combustion hearth.
Ensayo 1 Essay 1
En este contexto, en el presente ensayo se dispuso un calefactor residencial equivalente al del ensayo base, y se preparó el combustible sólido a disponer dentro del hogar de combustión de dicho calefactor, en forma equivalente al ensayo base. Como el volumen útil del hogar o cámara de combustión del calefactor ensayado no excede los 0,02 m3, se dimensionaron 3 trozos de madera de eucalipto de un largo de 0,25 m, con ancho variable para lograr la masa requerida para el ensayo, según el volumen útil de la cámara de combustión, basándose en una densidad de carga volumétrica de 112±11 ,2 kg/m3. In this context, in the present test a residential heater equivalent to that of the base test was arranged, and the solid fuel to be placed inside the combustion hearth of said heater was prepared, in a manner equivalent to the base test. As the useful volume of the hearth or combustion chamber of the heater tested does not exceed 0.02 m 3 , 3 pieces of eucalyptus wood with a length of 0.25 m were dimensioned, with variable width to achieve the mass required for the test. , according to the useful volume of the combustion chamber, based on a volumetric charge density of 112 ± 11.2 kg / m 3 .
A diferencia del ensayo base, se incorporó un medio poroso inerte de material Carburo de Silicio (SiC) en forma de disco de 200 mm de diámetro, 30 mm de espesor y porosidad del 82,5 %. Para este ejemplo, el disco de SiC se ubicó en forma horizontal en la pared inferior del hogar de combustión, con la carga de leña sobre dicho disco. Con esta configuración se espera que el disco genere un precalentamiento del aire primario que asciende por el calefactor y pasa a través del combustible, para mejorar la oxidación de la leña, disminuir el tiempo de evaporación de la humedad presente en la leña y disminuir el enfriamiento en la cámara de combustión causado por la entrada de aire frió; además de entregar calor mediante conducción y radiación al combustible. Ensayo 2 Unlike the base test, an inert porous medium made of Silicon Carbide (SiC) material was incorporated in the form of a disc with a diameter of 200 mm, a thickness of 30 mm and a porosity of 82.5%. For this example, the SiC disk was placed horizontally on the bottom wall of the combustion hearth, with the load of firewood on the disk. With this configuration, it is expected that the disk will generate a preheating of the primary air that rises through the heater and passes through the fuel, to improve the oxidation of the firewood, reduce the evaporation time of the moisture present in the firewood and reduce cooling. in the combustion chamber caused by the entry of cold air; in addition to delivering heat through conduction and radiation to the fuel. Essay 2
En el presente ensayo, a diferencia del ensayo 1 , se usaron dos semidiscos, preparados a partir de un disco de las mismas dimensiones que en el ejemplo 1 , los cuales fueron posicionados entre los leños de la carga de ensayo dentro de la cámara de combustión. Con esta configuración se espera que los semidiscos mediante conducción y radiación entreguen calor al combustible precalentando la mezcla aire-combustible, además de aportar calor a los gases de combustión que ascienden entre los espacios presentes entre un leño y otro. In the present test, unlike test 1, two semi-discs were used, prepared from a disc of the same dimensions as in example 1, which were positioned between the logs of the test load inside the combustion chamber. . With this configuration, it is expected that the semi-discs by conduction and radiation deliver heat to the fuel by preheating the air-fuel mixture, in addition to providing heat to the combustion gases that rise between the spaces between one log and another.
Conclusiones Conclusions
El calor entregado por la combustión de leña al ambiente mediante las paredes del calefactor fue notablemente mayor al usar el medio poroso inerte, llegando a un máximo de aproximadamente 1000 W, en comparación con el máximo de 500 W del calefactor sin medio poroso inerte, esto empleando máxima admisión de aire. Esto se debe al aumento de la temperatura promedio de la cámara de combustión al usar medio poroso inerte, lo que ocasiona un mayor flujo de calor por radiación y convección hacia el ambiente. El aumento de la temperatura de las paredes del calefactor se debe al fenómeno de transferencia de calor presente entre la reacción de la premezcla de aire-combustible y el medio poroso inerte, el cual genera un aumento de temperatura del medio poroso inerte producto del calor transferido desde la reacción de la premezcla de aire-combustible, logrando un aumento en la temperatura del hogar de combustión. The heat delivered by the combustion of wood to the environment through the walls of the heater was notably higher when using the inert porous medium, reaching a maximum of approximately 1000 W, compared to the maximum of 500 W of the heater without inert porous medium, this using maximum air intake. This is due to the increase in the average temperature of the combustion chamber when using inert porous medium, which causes a greater flow of heat by radiation and convection towards the environment. The increase in the temperature of the heater walls is due to the heat transfer phenomenon present between the reaction of the air-fuel premix and the inert porous medium, which generates an increase in temperature of the inert porous medium as a result of the heat transferred. from the reaction of the air-fuel premix, achieving an increase in the temperature of the combustion hearth.
En este contexto, la configuración del ensayo 2 presenta un mejor comportamiento con respecto a la emisión de CO en comparación con la configuración del ensayo 1 . Esta diferencia se debe a la configuración de los medios porosos inertes en cada ensayo, dentro de la cámara de combustión, ya que en el ensayo 2 dicho medio poroso inerte cubre una mayor altura del hogar, ocasionando además una transferencia de calor por convección desde la reacción de la premezcla de aire-combustible al medio poroso, por lo que los gases de combustión al ascender y entrar en contacto con los semidiscos cerámicos aumentan su temperatura y se vuelven a quemar bajando la concentración de CO. Además, la configuración del ensayo 1 , con el medio poroso inerte bajo el combustible sólido, provoca que los poros se saturen al producirse la ceniza durante el proceso de combustión, dificultando la circulación de la premezcla de aire-combustible a través de dicho medio poroso inerte. In this context, the configuration of test 2 exhibits a better performance with respect to the emission of CO compared to the configuration of test 1. This difference is due to the configuration of the inert porous media in each test, inside the combustion chamber, since in test 2 said inert porous media covers a greater height of the hearth, also causing heat transfer by convection from the reaction of the air-fuel premix to the porous medium, whereby the combustion gases as they rise and come into contact with the ceramic semi-discs increase their temperature and are burned again by lowering the CO concentration. In addition, the configuration of test 1, with the inert porous medium under the solid fuel, causes the pores to become saturated when the ash is produced during the combustion process, making it difficult for the air-fuel premix to circulate through said porous medium. inert.
En este contexto, el ensayo base, que no utiliza medio poroso inerte, presenta un rendimiento térmico de 68,91 %, mientras que el ensayo 1 presenta un rendimiento del 81 , 41 % y el ensayo 2 presenta un rendimiento del 91 ,04 %. Luego, se demuestra que el uso de los medios porosos inertes mejora considerablemente el rendimiento térmico del calefactor a leña ensayado, así como también se demuestra que posicionar el medio poroso inerte hacia las paredes laterales del calefactor, entre el combustible sólido y dichas paredes, resulta ventajosa por sobre la posición del medio poroso inerte bajo el combustible sólido. In this context, the base test, which does not use inert porous medium, has a thermal efficiency of 68.91%, while test 1 has a yield of 81.41% and test 2 has a yield of 91.04%. . Then, it is shown that the use of inert porous media considerably improves the thermal performance of the tested wood heater, as well as it is shown that positioning the inert porous media towards the side walls of the heater, between the solid fuel and said walls, results advantageous over the position of the inert porous medium under the solid fuel.

Claims

REIVINDICACIONES
1. Un sistema de combustión de combustibles sólidos, CARACTERIZADO porque comprende: un hogar de combustión que contiene combustible sólido en su interior, en donde dicho combustible sólido es sometido a un proceso de combustión al interior del hogar de combustión, generando gases de combustión; un medio poroso inerte dispuesto al interior del hogar de combustión, en donde dicho medio poroso inerte está en la cercanía del combustible sólido; y medios de control de flujo dispuestos en el hogar de combustión, en donde dichos medios de control de flujo se disponen para controlar la operación de: o al menos una entrada de aire dispuesta en el hogar de combustión, configurada para inyectar aire de admisión hacia el interior del hogar de combustión; y o al menos una salida de gases dispuesta en el hogar de combustión, configurada para liberar gases de combustión no reaccionados hacia el exterior del hogar de combustión, en la forma de gases de escape; en donde dichos medios de control de flujo están configurados para generar un flujo de aire de admisión y gases de combustión entre la al menos una entrada de aire y la al menos una salida de gases de escape, formándose una premezcla de aire de admisión y gases de combustión al interior del hogar de combustión; y en donde dichos medios de control de flujo y dicho medio poroso inerte están configurados para hacer circular dicha premezcla a través del medio poroso inerte, en particular, a través de los poros de dicho medio poroso inerte, provocando el precalentamiento del aire de admisión y la aceleración de la reacción de los gases de combustión dentro de dichos poros, combustionando la premezcla al interior de los poros del medio poroso inerte. 1. A solid fuel combustion system, CHARACTERIZED in that it comprises: a combustion hearth that contains solid fuel inside, wherein said solid fuel is subjected to a combustion process inside the combustion hearth, generating combustion gases; an inert porous medium arranged inside the combustion hearth, wherein said inert porous medium is in the vicinity of the solid fuel; and flow control means arranged in the combustion hearth, wherein said flow control means are arranged to control the operation of: o at least one air inlet arranged in the combustion hearth, configured to inject intake air towards the interior of the combustion hearth; and and or at least one gas outlet arranged in the combustion hearth, configured to release unreacted combustion gases to the outside of the combustion hearth, in the form of exhaust gases; wherein said flow control means are configured to generate a flow of intake air and combustion gases between the at least one air inlet and the at least one exhaust gas outlet, forming a premix of intake air and gases of combustion inside the combustion hearth; and wherein said flow control means and said inert porous medium are configured to circulate said premix through the inert porous medium, in particular, through the pores of said inert porous medium, causing preheating of the intake air and the acceleration of the reaction of the combustion gases within said pores, combustion of the premix within the pores of the inert porous medium.
2. El sistema de acuerdo con la reivindicación 1 , CARACTERIZADO porque la operación de la al menos una entrada de aire es controlada según la cantidad de aire deseada para el proceso de combustión. 2. The system according to claim 1, CHARACTERIZED in that the operation of the at least one air inlet is controlled according to the amount of air desired for the combustion process.
3. El sistema de acuerdo con cualquiera de las reivindicaciones 1-2,3. The system according to any of claims 1-2,
CARACTERIZADO porque la operación de la al menos una entrada de aire y/o de la al menos una salida de gases de escape son controladas según la circulación de premezcla deseada a través del medio poroso inerte. CHARACTERIZED in that the operation of the at least one air inlet and / or the at least one exhaust gas outlet are controlled according to the desired premix circulation through the inert porous medium.
4. El sistema de acuerdo con cualquiera de las reivindicaciones 1 -3,4. The system according to any of claims 1-3,
CARACTERIZADO porque el combustible sólido comprende dos o más unidades sólidas de diferentes dimensiones, posicionadas de forma aleatoria al interior del hogar de combustión. CHARACTERIZED because the solid fuel comprises two or more solid units of different dimensions, randomly positioned inside the combustion hearth.
5. El sistema de acuerdo con cualquiera de las reivindicaciones 1 -4,The system according to any of claims 1-4,
CARACTERIZADO porque el medio poroso inerte comprende al menos una unidad porosa inerte, dispuesta en contacto físico con el combustible sólido. CHARACTERIZED in that the inert porous medium comprises at least one inert porous unit, arranged in physical contact with the solid fuel.
6. El sistema de acuerdo con la reivindicación 5, CARACTERIZADO porque el medio poroso inerte comprende dos o más unidades porosas inertes, dichas dos o más unidades porosas inertes dispuestas al interior del hogar de combustión en diferentes posiciones, que aseguran el contacto físico con el combustible sólido. 6. The system according to claim 5, CHARACTERIZED in that the inert porous medium comprises two or more inert porous units, said two or more inert porous units arranged inside the combustion hearth in different positions, which ensure physical contact with the solid fuel.
7. El sistema de acuerdo con la reivindicación 6, CARACTERIZADO porque una primera unidad porosa inerte se posiciona entre el combustible sólido y una pared lateral del hogar de combustión y porque una segunda unidad porosa inerte se posiciona entre el combustible sólido y otra pared lateral del hogar de combustión. The system according to claim 6, CHARACTERIZED in that a first inert porous unit is positioned between the solid fuel and a side wall of the combustion hearth and because a second inert porous unit is positioned between the solid fuel and another side wall of the combustion hearth.
8. El sistema de acuerdo con la reivindicación 7, CARACTERIZADO porque una tercera unidad porosa inerte se posiciona entre el combustible sólido y una pared posterior del hogar de combustión. 8. The system according to claim 7, CHARACTERIZED in that a third inert porous unit is positioned between the solid fuel and a rear wall of the combustion hearth.
9. El sistema de acuerdo con cualquiera de las reivindicaciones 1 -8,The system according to any of claims 1-8,
CARACTERIZADO porque el combustible sólido se selecciona entre biomasa, carbón o una combinación de ambos. CHARACTERIZED because the solid fuel is selected from biomass, coal or a combination of both.
10. El sistema de acuerdo con cualquiera de las reivindicaciones 1 -9,The system according to any of claims 1-9,
CARACTERIZADO porque el medio poroso inerte es de material cerámico, comprendiendo una porosidad de al menos el 50% y una densidad de poros de al menos 20 ppi. CHARACTERIZED because the inert porous medium is made of ceramic material, comprising a porosity of at least 50% and a pore density of at least 20 ppi.
11. El sistema de acuerdo con cualquiera de las reivindicaciones 1-10,11. The system according to any of claims 1-10,
CARACTERIZADO porque comprende además una unidad de adquisición de datos, para adquirir datos de operación del sistema de combustión. CHARACTERIZED because it also comprises a data acquisition unit, to acquire operating data of the combustion system.
12. Un método de combustión de combustibles sólidos, CARACTERIZADO porque comprende las siguientes etapas: a) disponer combustible sólido y un medio poroso inerte al interior de un hogar de combustión de un sistema de combustión de combustibles sólidos, en donde el medio poroso inerte se dispone en la cercanía del combustible sólido; b) inyectar aire de admisión hacia el interior del hogar de combustión, a través de al menos una entrada de aire dispuesta en el hogar de combustión, en donde la inyección de dicho aire de admisión es controlada por medios de control de flujo dispuestos en el hogar de combustión; c) encender el combustible sólido, sometiendo dicho combustible sólido a un proceso de combustión al interior del hogar de combustión; d) generar un flujo de aire de admisión y gases de combustión entre la al menos una entrada de aire y al menos una salida de gases de escape también dispuesta en el hogar de combustión, en donde dicho flujo de aire de admisión y gases de combustión es controlado por dichos medios de control de flujo, formándose una premezcla de aire de admisión y gases de combustión al interior del hogar de combustión; e) hacer circular la premezcla a través del medio poroso inerte, en particular, a través de los poros de dicho medio poroso inerte, para precalentar el aire de admisión y acelerar la reacción de los gases de combustión dentro de dichos poros, en donde la circulación de la premezcla es controlada por dichos medios de control de flujo y dicho medio poroso inerte, y en donde dicha premezcla se combustiona al interior de los poros del medio poroso inerte; y f) liberar gases de combustión no reaccionados hacia el exterior del hogar de combustión, en la forma de gases de escape, en donde la liberación de dichos gases de escape es controlada por dichos medios de control de flujo. 12. A method of combustion of solid fuels, CHARACTERIZED because it comprises the following stages: a) placing solid fuel and an inert porous medium inside a combustion hearth of a solid fuel combustion system, where the inert porous medium is has in the vicinity of solid fuel; b) injecting intake air into the combustion hearth, through at least one air inlet arranged in the combustion hearth, wherein the injection of said intake air is controlled by flow control means arranged in the combustion hearth; c) igniting the solid fuel, subjecting said solid fuel to a combustion process inside the combustion hearth; d) generating a flow of intake air and combustion gases between the at least one air inlet and at least one exhaust gas outlet also arranged in the combustion hearth, wherein said flow of intake air and combustion gases it is controlled by said flow control means, forming a premix of intake air and combustion gases inside the combustion hearth; e) circulating the premix through the inert porous medium, in particular, through the pores of said inert porous medium, to preheat the intake air and accelerate the reaction of the combustion gases within said pores, where the circulation of the premix is controlled by said flow control means and said inert porous medium, and wherein said premix is combusted within the pores of the inert porous medium; and f) releasing unreacted combustion gases to the outside of the combustion hearth, in the form of exhaust gases, wherein the release of said exhaust gases is controlled by said flow control means.
13. El método de acuerdo con la reivindicación 12, CARACTERIZADO porque la etapa de inyectar aire de admisión es controlada según la cantidad de aire deseada para el proceso de combustión. The method according to claim 12, CHARACTERIZED in that the step of injecting intake air is controlled according to the amount of air desired for the combustion process.
14. El método de acuerdo con cualquiera de las reivindicaciones 12-13, CARACTERIZADO porque la etapa de inyectar aire de admisión y/o la etapa de liberar gases de escape son controladas según la circulación de premezcla deseada a través del medio poroso inerte. The method according to any of claims 12-13, CHARACTERIZED in that the step of injecting intake air and / or the step of releasing exhaust gases are controlled according to the desired premix circulation through the inert porous medium.
15. El método de acuerdo con cualquiera de las reivindicaciones 12-14, CARACTERIZADO porque la etapa de disponer el combustible sólido comprende disponer dos o más unidades sólidas que forman dicho combustible sólido, donde dichas unidades sólidas son de diferentes dimensiones y son posicionadas de forma aleatoria al interior del hogar de combustión. 15. The method according to any of claims 12-14, CHARACTERIZED in that the step of arranging the solid fuel comprises arranging two or more solid units that form said solid fuel, where said solid units are of different dimensions and are positioned in a random inside the combustion hearth.
16. El método de acuerdo con cualquiera de las reivindicaciones 12-15, CARACTERIZADO porque la etapa de disponer el medio poroso inerte al interior del hogar de combustión comprende disponer al menos una unidad porosa inerte al interior del hogar de combustión en contacto físico con el combustible sólido. 16. The method according to any of claims 12-15, CHARACTERIZED in that the step of arranging the inert porous medium inside the combustion hearth comprises placing at least one inert porous unit inside the combustion hearth in physical contact with the solid fuel.
17. El método de acuerdo con la reivindicación 16, CARACTERIZADO porque la etapa de disponer el medio poroso inerte al interior del hogar de combustión comprende disponer dos o más unidades porosas inertes al interior del hogar de combustión, dichas dos o más unidades porosas inertes dispuestas al interior del hogar de combustión en diferentes posiciones, que aseguran el contacto físico con el combustible sólido. 17. The method according to claim 16, CHARACTERIZED in that the step of arranging the inert porous medium inside the combustion hearth comprises arranging two or more inert porous units inside the combustion hearth, said two or more inert porous units arranged inside the combustion hearth in different positions, which ensure physical contact with the solid fuel.
18. El método de acuerdo con la reivindicación 17, CARACTERIZADO porque una primera unidad porosa inerte es posicionada entre el combustible sólido y una pared lateral del hogar de combustión y porque una segunda unidad porosa inerte es posicionada entre el combustible sólido y otra pared lateral del hogar de combustión. 18. The method according to claim 17, CHARACTERIZED in that a first inert porous unit is positioned between the solid fuel and a side wall of the combustion hearth and in that a second inert porous unit is positioned between the solid fuel and another side wall of the combustion hearth.
19. El método de acuerdo con la reivindicación 18, CARACTERIZADO porque una tercera unidad porosa inerte es posicionada entre el combustible sólido y una pared posterior del hogar de combustión. 19. The method according to claim 18, CHARACTERIZED in that a third inert porous unit is positioned between the solid fuel and a rear wall of the combustion hearth.
20. El método de acuerdo con cualquiera de las reivindicaciones 12-19, CARACTERIZADO porque el combustible sólido es seleccionado entre biomasa, carbón o una combinación de ambos. 20. The method according to any of claims 12-19, CHARACTERIZED in that the solid fuel is selected from biomass, coal or a combination of both.
21. El método de acuerdo con cualquiera de las reivindicaciones 12-20, CARACTERIZADO porque el medio poroso inerte es de material cerámico, comprendiendo una porosidad de al menos el 50% y una densidad de poros de al menos 20 ppi. 21. The method according to any of claims 12-20, CHARACTERIZED in that the inert porous medium is made of ceramic material, comprising a porosity of at least 50% and a pore density of at least 20 ppi.
22. El método de acuerdo con cualquiera de las reivindicaciones 12-21 , CARACTERIZADO porque comprende además la etapa de adquirir datos de operación del sistema de combustión, mediante una unidad de adquisición de datos. 22. The method according to any of claims 12-21, CHARACTERIZED in that it further comprises the step of acquiring operation data of the combustion system, by means of a data acquisition unit.
PCT/CL2020/050179 2019-12-16 2020-12-15 System and method for improving the combustion process of a solid fuel by means of an inert porous medium WO2021119871A1 (en)

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