Hot gas flow control valve, coke combustion process, coking oven and industrial plant.

Description

10 Hot gas flow control valve, coke combustion process, coking oven and industrial plant. Field of Invention

[001] The present invention relates to a hot gas flow control valve for coking ovens: high thermal resistance and adverse conditions, in particular a butterfly type valve designed to operate in extreme temperature and pressure conditions, as well as in corrosive environments, being applicable to gas flow control in industrial ovens, especially in battery ovens for coke production.

[002] In addition to optimizing internal thermal control, the invention aims to improve the residence time of combustion gases, reduce the coke formation cycle, and produce a high-quality material for metallurgical use. The valve can also be employed for use in refineries and high-temperature furnaces in the steel and cement industries. Background of the Invention

[003] In heat recovery furnace systems (HRSG), also known as horizontal coke ovens (1), the gas flow is essential for controlling coal carbonization and for process efficiency.

[004] The heating system for coking in Heat Recovery type furnaces is supplied by the volatile material that is released by the coal. The volatile matter consists of tar, hydrocarbon, hydrogen, carbon monoxide and other gases that are burned in the coking chambers of the furnaces.

[005] In these furnaces, volatiles are burned through a section of descending channels just below the dome called down comers, as well as under the floor of the chambers. Thus, coking of the coal occurs both at the top of the coal cake and at the bottom of the cake. The air needed to burn the volatile matter is supplied using air holes in the dome (top air) and Petition 870250006263, dated 01 / 27 / 2025, page 8 / 23 / 10 supported by induced and controlled injection through decarbonization lances.

[006] Heat Recovery furnaces (HRSG) necessarily operate under negative pressure, where collection ducts (2) connect several coking chambers (3) and transport the hot gases to feed a power generation system at the end of each battery.

[007] However, each time the doors (4) are opened for unloading and subsequent loading, a significant volume of fresh air is drawn into the chamber due to the negative pressure of the furnace, generating a loss of temperature and a consequent reduction in the heat stored in the chamber walls. Furthermore, the injection of fresh air being drawn directly through the uptakers (5) causes a feedback of the combustion of volatiles inside these collector ducts (2), causing an overheating of the gases and a considerable increase in temperature on the surface of the refractory lining of these ducts, often causing catastrophic failure of the same.

[008] Frequent failures in the refractory material result in high costs, maintenance shutdowns, and a direct impact on the quality of the coke produced.

[009] Some current systems lack effective devices to control gas flow precisely, especially under extreme operating conditions.

[0010] Coke is produced in the coking chambers (3) by first loading the coal “cake” (8) into the chamber, heating this cake in an oxygen-controlled environment, extracting the volatiles from the coal and oxidizing the volatiles to generate heat inside the chamber in a process that can last from 48 to 76 h depending on the volume of the “cake” (8) to be processed. The burning of the volatiles releases heat to regeneratively process the coking of the coal and maintain the chamber walls (6) with an adequate energy charge. Petition 870250006263, dated 01 / 27 / 2025, page 9 / 23 / 10

[0011] The coking cycle begins from the first moment the coal cake (8) is introduced into the chamber. The temperatures of the walls (6) and, especially, of the hearth (7) must be high in order to start the ignition of the coal immediately. 50% of the total heat transfer is radiated from the dome (9) and walls (6) to the upper surface of the coal cake and 50% is transferred by conduction through the hearth (7) which in turn is heated by the burning of volatiles that enter the channels of the downcomers.

[0012] Thus, all surfaces of the coal “cake” receive energy for the carbonization process of the coal plastic flow, forming a high-strength, high-carbon content coke.

[0013] Therefore, precisely controlling the internal system pressure and the residence time of the gases resulting from the combustion of volatiles in the coking chambers becomes a pressing need for obtaining high-quality coke.

[0014] The state of the art presents some alternative solutions to improve the coking process. In this regard, we can cite documents CN 118085892 and CN 115143796. These documents relate to a type of flow diversion valve quite different from the valve of the present invention.

[0015] Another document relevant to the technical field in question is PI 0603433-0, relating to a charcoal furnace which in no way interferes with the valve of the present invention. Summary of the Invention

[0016] In a first aspect, the present invention provides a valve capable of controlling the flow of hot gases in a furnace.

[0017] Specifically, the valve (10) of the present invention is capable of controlling certain variables that create disturbances in the system affecting a series of variables, controlling both the entry of hot gases through the channels Petition 870250006263, dated 01 / 27 / 2025, page 10 / 23 / 10 ascenders (up takers) as well as restricting the entry of cold air into the chamber that possibly enters through the gaps between the door and buckstay / lintel.

[0018] The present invention aims to: 1. Regulate the flow of gases in the uptakers during loading and unloading operations, ensuring the optimization of the system's thermal efficiency through precise control of gas fluid dynamics, minimization of energy losses, and maintenance of ideal operating conditions; 2. Control the residence time of combustion gases by optimizing operational parameters, aiming to maximize the system's energy efficiency and minimize coke formation time, promoting more homogeneous and controlled coking; 3. Optimize the combustion efficiency of volatile compounds, ensuring that the down-comers to the hearth remain unobstructed, and promote uniform heat distribution across the hearth walls, contributing to operational stability and maximizing the thermal performance of the system; 4. Extend the service life of refractories (6) by selecting and applying high-performance materials, ensuring high resistance to abrasion, corrosion and, above all, thermal shock. Refractories must be able to withstand temperatures up to 1500°C and operate under a negative pressure of 200 Pascal, guaranteeing the structural integrity and operational reliability of the system; 5. Ensure the thermal compatibility of the valve's internal elements with the operating temperatures to which they will be subjected, preventing thermal shock and consequently extending the service life of the valve obturator. This requires the use of materials with appropriate coefficients of thermal expansion and a design that minimizes gradients. Petition 870250006263, dated 27 / 01 / 2025, page 11 / 23 / 10 excessive thermal stresses during the operational cycles to which they are subjected 6. Reduce the structural impact resulting from the valve's weight, ensuring that its installation does not require resizing existing support structures. This can be achieved by optimizing the valve design, using materials with high mechanical strength and low specific weight, without compromising the structural integrity and functionality of the equipment. 7. Implement an automated control system, integrating the hot gas flow control valves (10) into a central control, allowing continuous monitoring and precise adjustment of operating parameters. This automation aims to optimize process efficiency, reduce the need for manual interventions and ensure a quick response to variations in operating conditions; 8. Reduce carbon and particulate matter emissions through optimization of combustion processes and advanced emissions control, contributing to the environmental sustainability of the system. These improvements aim to meet current environmental regulations, minimize environmental impact, and improve air quality around the facilities.

[0019] In a further aspect, the present invention also provides furnaces comprising the valves (10) described herein, and plants comprising the furnaces optimized with the valves (10). These furnaces are then optimized furnaces that provide better coke combustion.

[0020] In a further aspect, the present invention introduces an optimized coke burning process, in which the incorporation of valves (10) in the coking ovens allows for more precise control of the gas flow, resulting in an increase in the thermal and operational efficiency of the system. This improvement contributes to more efficient combustion, reducing energy losses and optimizing the quality of the coke produced. Petition 870250006263, dated 01 / 27 / 2025, page 12 / 23 / 10

[0021] These and other objects of the invention will be better detailed in the following description. Brief Description of the Figures

[0022] Figure 1 shows a state-of-the-art heat recovery furnace.

[0023] Figure 2 shows a cross-sectional view of a heat recovery furnace, illustrating the ascending channels (5), sole flue (7) and dome (9).

[0024] Figure 3 shows a perspective view of the coking chamber (3) of a heat recovery furnace.

[0025] Figure 4 shows a cross-sectional view of the ascending channels, illustrating the positioning of the valve (10).

[0026] Figure 5 shows a perspective view of the valve (10) of the present invention.

[0027] Figure 6 shows a detail of the obturator (11) and the intermediate twist tube (12) of the valve (10).

[0028] Figure 7 shows a cross-sectional view of the upper region of the valve (10), detailing the valve movement system (10). Detailed Description of the Invention

[0029] The detailed description below is intended only to exemplify some of the numerous ways of carrying out the invention, and should not be considered restrictive, but rather explanatory.

[0030] The valve (10) of the present invention is a butterfly type valve, comprising obturator (11), metal head (13), and a body (17) comprising lightweight insulating refractory materials (18).

[0031] The gas passage shutter (11) is designed to allow full flow when open, without restriction of useful area. The shutter (11) has an increased area in its radius of action in order to compensate for the thickness of the shutter and even its axis, as shown in Figure 6. Preferably, it has a rectangular shape, equipped with an intermediate torsion tube (12) that is fixed to the head (13) by means of refractory steel clamps (14) that provide a safe rotational movement around its axis. Petition 870250006263, dated 01 / 27 / 2025, page 13 / 23 / 10

[0032] The obturator (11) is preferably produced with advanced ceramic made of high-performance refractory material known in the prior art. Examples of refractories according to the present invention include, without limitation, high alumina or mullite or zirconium or mullite zirconium, silicon carbide or chemically bonded or recrystallized silicon carbide resistant to high temperatures (up to 1500°C), corrosion by metal oxides and sulfur, and thermal shock.

[0033] The metal head (13) is made of refractory steel, withstands high temperatures and chemical attack, and is designed to fix the ceramic obturator (11) and transmit the opening and closing motion. The motion transmission is made through the upper disc (15), which connects the head (13) to a roller system (16) or bearing, allowing smooth and efficient movement with low torsional force. Figure 7 illustrates a preferred embodiment of this motion transmission system.

[0034] The head (13) can be operated manually via a gearbox with a handwheel or automatically with an electric or pneumatic actuator for remote control.

[0035] The valve body (17) is constructed of carbon steel sheet metal on its exterior and coated with refractory materials that can withstand the operating conditions to which it will be subjected. Specifically, the valve (10) of the present invention uses lightweight insulating refractory materials (18) in order to reduce the total weight of the system, avoiding structural overload on the vaults of the battery chambers.

[0036] Among the various advantages of the valve of the present invention, we can mention: 1. Operational Efficiency:

[0037] Improves control of the internal temperature of the chambers, allowing for a more homogeneous and precise thermal distribution, which results in greater stability in the process and in the quality of the final product; Petition 870250006263, dated 01 / 27 / 2025, page 14 / 23 / 10

[0038] Increasing the residence time of the gases, providing better use of thermal energy and optimizing the coking process, reducing losses and improving the overall efficiency of the system. 2. Durability:

[0039] Advanced materials used ensure high resistance to mechanical, chemical and thermal wear, extending the service life of components and minimizing maintenance needs. These materials are designed to withstand extreme operating conditions, such as high temperatures, corrosive environments and intense mechanical stress, ensuring the structural integrity and long-term reliability of the system. 3. Cost Reduction:

[0040] Reduced wear on the refractory lining of the collector ducts, resulting in lower maintenance and component replacement costs, as well as improved operational efficiency by maintaining ideal operating conditions for longer;

[0041] Extends the service life of chambers and ducts, reducing the need for frequent repairs and parts replacements, and reduces the coking time of the coal "cake," speeding up the process and increasing production capacity, which contributes to a significant reduction in overall operating costs. 4. Operational Flexibility:

[0042] Enables integration with automated control systems, offering greater precision and adaptability in operations, with the ability to monitor and adjust parameters in real time to optimize process performance.

[0043] Lightweight and modular design, facilitating installation in various types of systems, including batteries with extended lifespan, allowing for simplified upgrades and maintenance, as well as providing greater flexibility in adapting to different operating conditions and production requirements. Operation Petition 870250006263, dated 01 / 27 / 2025, page 15 / 23 / 10

[0044] The valve (10) of the present invention can be installed in any pre-existing coking oven, allowing for its backward compatibility and integration with systems already in operation. Thus, ovens using the valve of the present invention are within the scope of the invention. Furthermore, these technologies can be incorporated into coking plants, extending the scope of the invention to also include plants that use this innovation.

[0045] The furnaces comprising the valves (10) of the present invention are consequently optimized furnaces. This optimization of the coke furnace aims to maximize the yield of the coking chambers (3) generating a coke with better quality. The yield can be defined by the difference between the amount of coal placed in the chamber (3) and the amount of coke produced. And, quality is defined by the stability of the coke after CRS reaction, average size and C content. These have been considered the most important factors for evaluating coke for use in blast furnaces.

[0046] Reactivity (CRI) and compressive strength (CSR) have also been extremely valuable items in the design and calculation of blast furnace charges. Coke with a high degree of CSR can provide a direct reduction in coke consumption. It is estimated that 1-1.5 kg of coke can be saved for each percentage point increase in the CSR index.

[0047] The coking rate can be optimized by improving the temperature profiles in the walls and hearth of the coking chambers and by maintaining the heat stored in the walls of these chambers. The temperature profiles in the walls (6) and hearth (7) are crucial for obtaining coke with good size, hardness and CSR.

[0048] Similarly, the coke burning process in a furnace comprising the valve of the present invention can be summarized as follows:

[0049] During normal operation, the valve (10) remains open to allow the continuous flow of combustible gases to the collector ducts. During loading and unloading, the valve (10) is adjusted via the reducer with handwheel or Petition 870250006263, dated 01 / 27 / 2025, page 16 / 23 / 10 automatic actuators to control the flow of gases, restricting the entry of fresh air into the uptakers that carry these gases to the main collector [2].

[0050] During the carbonization cycle of the coal, the valve (10) can be operated in order to create a slightly positive environment to increase the internal temperature and prevent fresh air from entering through the gaps in the doors or holes in the chamber.

[0051] The design and material specification of the obturator (11) and the head (13) were selected to ensure good resistance to the extreme conditions to which the valve (10) will be subjected, maintaining precise flow control and minimizing thermal losses in the chamber walls.

[0052] This control is only possible with the installation of Flow Control Valves (10) on each gas outlet of the chamber, that is, one on the up-takers (5) next to the coal cake inlet door (8) and another on the up-takers next to the door (4) on the coke side.

[0053] The valve (10) is positioned over the 4 up-takers (5) before being led to the main collector duct (2). The valves (10) are equipped with obturators (11) that can be positioned in a 90° stroke, allowing for total or partial restriction of the passage of hot gases from the coking chamber (3), providing various positions between fully open and fully closed, and the gas flow can be controlled by adjusting the relative position of the obturator according to the need for maintenance or extraction of gases from inside the chamber. Petition 870250006263, dated 01 / 27 / 2025, page 17 / 23

Claims

1 / 2 Claims 1. Hot gas flow control valve (10) characterized by comprising a shutter (11), a metal head (13), and a body (17) comprising lightweight insulating refractory materials (18).

2. Valve (10), according to claim 1, characterized in that the obturator (11) has a rectangular shape and an increased area in its radius of action.

3. Valve (10) according to claim 1, characterized by comprising an intermediate twist tube (12) that is fixed to the head (13) by means of clamps (14).

4. Valve (10), according to claim 1, characterized in that the head transmits motion by means of an upper disc (15), which connects the head (13) to a roller system (16).

5. Valve (10), according to claim 1, characterized in that the head (13) is operated manually or automatically.

6. Valve (10), according to claim 1, characterized in that the obturator is made of a material selected from high alumina, mullite, zirconium, mullite zirconium, silicon carbide, chemically bonded or recrystallized silicon carbide, and combinations thereof.

7. Coking oven characterized by comprising at least one valve (10) as defined in any one of claims 1 to 6.

8. Industrial plant characterized by comprising at least one coking oven as defined in claim 7.

9. Coke burning process characterized by comprising a step of restricting the entry of fresh air into the ascending channels by adjusting the valve (10), as defined in any of claims 1 to 6, present in the coking oven. Petition 870250006263, dated 27 / 01 / 2025, page 18 / 23 2 / 2 10. Coke burning process according to claim 9, characterized by comprising a subsequent coal carbonization step where the valve (10) creates a slightly positive environment. Petition 870250006263, dated 27 / 01 / 2025, pp. 19 / 23

Images