SISTEMA DE FORNALHA COM CÂMARA DE PIRÓLISE E PÓS-COMBUSTÃO PARA QUEIMA TOTAL DE BIOMASSA AGRÍCOLA E OUTROS MATERIAIS

Description

/ 4 Furnace system with pyrolysis chamber and post-combustion for complete combustion of agricultural biomass and other materials. TECHNICAL FIELD

[001] The present utility model relates to the field of thermal equipment applied to agricultural drying and energy recovery from plant biomass, particularly combustion systems intended for the controlled burning of low-density agricultural residues.

[002] The model applies especially to the burning of coffee straw and equivalent organic materials, and can operate in direct or indirect grain drying processes or in other industrial thermal equipment. STATE OF THE ART

[003] Conventional systems exhibit incomplete combustion, intense smoke emission, low thermal efficiency, and require significant human intervention. The present solution overcomes these limitations with a primary pyrolysis chamber, forced post-combustion, automatic feeding, and internal mechanical control with low smoke emission. Different combustion systems are known for both agricultural drying and energy recovery from plant residues. However, these solutions do not fully meet the operational and environmental requirements associated with burning low-density biomass, such as coffee straw, nor do they offer effective mechanisms for complete combustion of gases and smoke reduction.

[004] Patent MU 8900605-4 describes a carbonization furnace system coupled to a furnace with a post-combustion duct intended for burning gases from carbonization. Although there is reference to the complementary burning of gases, this arrangement is primarily aimed at the production of charcoal and does not include automatic feeding, internal mechanical control of the biomass, or a primary chamber operating as a pyrolysis reactor dedicated to light agricultural residues.

[005] Document PI 0606008-0, relating to a coffee dryer, describes a furnace that operates at high temperatures (800-1000 °C) to reduce smoke emission. Although it mentions a reduction in particulate matter, it is a solution based on Petition 870260022314, dated 11 / 03 / 2026, p. 6 / 34 / 4 temperature increase, without the existence of a primary pyrolysis chamber, a secondary post-combustion chamber, directed, or mechanisms designed to prevent biomass compaction during burning.

[006] Patent MU 9002171-1 presents a coffee dryer with a fan and heated air conduction, but does not incorporate a pyrolysis chamber, does not address the recombustion of pyrolytic gases, nor does it propose a specific solution for agricultural biomass that is difficult to burn, such as coffee straw. Additionally, patent MU 8302750-5 describes an indirect flame furnace for grain dryers and aerators, establishing already known indirect fire principles. However, this solution does not address the controlled thermal decomposition of biomass, does not have a chamber dedicated to the recombustion of gases with supplementary directed air injection, and does not address internal mechanisms for homogenizing flammable material, such as mechanical agitators.Thus, although the cited documents contribute to the existing technological landscape, none of them presents the specific combination of elements proposed in this application: a primary chamber operating as a pyrolysis reactor, an integrated automatic feeder, an internal mechanical agitator, a secondary chamber and a post-combustion chamber dedicated to the recombustion of pyrolysis gases, and supplementary air injection strategically positioned to promote complete combustion and substantially reduce the emission of smoke and particulates resulting from the burning of coffee straw.

[007] Thus, known equipment does not have a construction capable of promoting successive combustion of gases generated by the pyrolysis of light agricultural biomass. TECHNICAL PROBLEM

[008] Burning low-density agricultural biomass produces a large volume of smoke and particulates, reducing thermal efficiency and hindering its continuous use in agricultural processes.

[009] Incomplete combustion causes energy loss, operational instability and the need to replace it with commercial fuels. Petition 870260022314, dated 11 / 03 / 2026, page 7 / 34 / 4

[010] There is therefore a need for a construction system that enables the progressive combustion of gases generated by biomass, increasing thermal efficiency and reducing emissions. PROPOSED SOLUTION

[011] The model comprises a furnace consisting of a primary chamber (A2) configured as a pyrolysis reactor, in which biomass is subjected to controlled combustion with initial oxygen limitation.

[012] The primary chamber (A2) receives biomass by means of an automatic feeder (B) through the inlet hole (A10).

[013] Inside the primary chamber there is a mechanical agitator (A7) designed to move the combustible material and prevent compaction during pyrolysis.

[014] The generated gases are conducted to a secondary chamber (A3) located above and in continuous flow with the post-combustion chamber (A5).

[015] At least one supplemental air injector (A4) provides additional oxygen directly into the gas path, promoting successive recombustion.

[016] The resulting flow is directed to the exhaust duct (A6) after multiple combustion stages.

[017] The construction set establishes an upward path for the gases with progressive combustion before exiting. BRIEF DESCRIPTION OF THE DRAWINGS

[018] Figure 1 shows a view of the furnace with the air outlet identified (A6).

[019] Figure 2 shows a left side view with access to the internal chambers.

[020] Figure 3 shows a front view with access to the internal chambers.

[021] Figure 4 shows the furnace assembly with feeder and fan. DETAILED DESCRIPTION

[023] During operation, biomass is introduced into the primary chamber (A2) by the automatic feeder (B). Petition 870260022314, dated 11 / 03 / 2026, page 8 / 34 / 4

[024] A controlled combustion layer is formed where thermal decomposition of the organic material occurs.

[025] The mechanical stirrer (A7) promotes continuous or intermittent homogenization of the combustible material.

[026] The ascending pyrolytic gases reach the secondary chamber (A3).

[027] The air injector (A4) promotes turbulence and temperature increase, favoring ignition of the gases.

[028] Subsequent combustion occurs in the afterburner chamber (A5).

[029] The resulting heated air is directed to the associated thermal process and subsequently conducted to the duct (A6) for exhaust by the fan (C)

[030] After the initial external ignition, the operation becomes self-sustaining due to the recombustion of the generated gases. EXAMPLES OF IMPLEMENTATION

[031] The system can operate in direct fire mode by directing heated air directly to the dryer.

[032] Alternatively, it can operate on indirect fire by means of an associated heat exchanger.

[033] The automatic feeder (B) may have a programmable timer for feed control.

[034] The agitator (A7) can operate continuously or in cycles as needed for thermal purposes.

[035] Inspection and cleaning doors and drains (A8,A9,A11,A12) allow maintenance and removal of waste. Petition 870260022314, dated 11 / 03 / 2026, page 9 / 34

Claims

1 / 2 CLAIMS 1. Furnace system for burning agricultural biomass, characterized by comprising a primary chamber (A2) configured as a pyrolysis reactor provided with a lower grate (A14) and a biomass inlet orifice (A10) connected to an automatic feeder (B), a mechanical agitator (A7) disposed inside the primary chamber (A2) configured to promote continuous or intermittent movement of the biomass and prevent its compaction during pyrolysis, a secondary chamber (A3) positioned above the primary chamber (A2) and in direct communication with it intended for receiving the generated pyrolytic gases, a post-combustion chamber (A5) disposed above the secondary chamber (A3) and in continuous flow with it,at least one supplemental air injector (A4) associated with the secondary chamber (A3) and / or the afterburner chamber (A5) configured to introduce additional air directly into the path of the pyrolytic gases and an exhaust duct (A6) connected to the afterburner chamber (A5), wherein the constructive arrangement of the chambers (A2, A3, A5) and the supplemental air injector (A4) establishes an upward path for the gases promoting successive recombustion before exiting through the exhaust duct (A6).

2. System according to claim 1, characterized in that the automatic feeder (B) comprises a mechanism driven by an electric motor controlled by a programmable electronic timer capable of regulating the frequency and volume of biomass feed into the primary chamber (A2).

3. System according to any of the preceding claims, characterized in that the mechanical agitator (A7) comprises a rotating shaft provided with radially distributed blades or rods promoting homogenization of the combustible material inside the primary chamber (A2).

4. System according to any of the preceding claims, characterized in that the secondary chamber (A3) has an internal geometry configured to induce turbulence in the flow of pyrolytic gases, favoring their ignition and recombustion.

5. System according to any of the preceding claims, characterized by the supplementary air injector (A4) being positioned laterally or superiorly to the secondary chamber (A3) and / or the after-combustion chamber (A5) directing airflow to the pyrolytic gas passage zone.

6. System according to any of the preceding claims, characterized by comprising means of conducting the generated heat for operation in direct fire mode by conducting heated air directly to the drying process or in indirect fire mode by means of an associated heat exchanger.

7. System according to any of the preceding claims, characterized by using an external ignition source only in the initial phase of operation, subsequently maintaining self-sustained combustion through the recombustion of pyrolytic gases generated in the primary chamber (A2).

8. System according to any of the preceding claims, characterized by comprising inspection doors (A9), cleaning doors (A11, A12) and biomass relief drain (A8) arranged in the furnace structure for maintenance and operational safety. Petition 870260022314, dated 11 / 03 / 2026, page 12 / 34

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