Continuous heating kiln

Abstract

The invention discloses a continuous heating kiln which comprises a kiln body and further comprises a fuel gas combustion system and an electric heating system, the fuel gas combustion system comprises hot gas heating pipelines, the hot gas heating pipelines comprise first hot gas pipelines and second hot gas pipelines, the first hot gas pipelines are arranged on the upper side and the lower side in the kiln body, and the second hot gas pipelines are arranged on the upper side and the lower side in the kiln body. The second hot air pipelines are arranged on the left side and the right side in the furnace body in the conveying direction of the kiln, the electric heating system comprises electric heating elements used for heating, compensating and temperature adjusting, and the electric heating elements are arranged on the upper side and the lower side or / and the left side and the right side in the furnace body. The basic temperature is provided for heating the kiln by arranging the gas combustion system, and then the temperature in the kiln is compensated and accurately regulated by arranging the electric heating system, so that low-cost rapid temperature rise in the kiln and accurate regulation of the temperature in the kiln are realized at the same time, the production cost is greatly reduced, and the service life of an electric heating component is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of heat treatment / material sintering equipment, and in particular relates to a heating kiln. Background Art

[0002] For continuous heating kilns, taking roller kilns as an example, the heating elements pass through the furnace horizontally from the top and bottom, and the materials and the rollers on which the materials are placed are placed between the upper and lower heating elements. Electric heating is a widely used heating method for continuous heating kilns. Electric heating kilns can accurately and quickly control the heating temperature, have good sintering effects on materials, especially temperature-sensitive materials, have high yields, and have little impact on the environment. They can be widely used in powder metallurgy, petrochemicals, electronics, light industry, daily chemicals, and pharmaceuticals.

[0003] Before the material enters the kiln, the kiln needs to be heated to the required temperature. Although the electric heating roller kiln can accurately control the heating temperature, the cost of electricity is relatively high for production processes that require kiln preheating, long-term continuous operation, and shutdown for insulation, especially for developed areas where industrial electricity is relatively expensive. In addition, the volume of the continuous heating kiln is generally large, and the heat dissipation loss is also large. The electricity cost has become one of the main cost components of its products. Manufacturers of new energy material sintering, heat treatment, etc. with large output are generally large energy consumers in their regions. In the energy classification system, electric energy is the highest quality form of energy with the highest exergy value. Direct conversion into thermal energy for use is a waste of high-quality energy.

[0004] Humans have a long history of using kilns that use low-cost fossil fuels such as coal and natural gas. my country has been using coal as a fuel for kilns for sintering ceramics since the Song Dynasty, while foreign countries began to use coal and natural gas as fuels in industrial kilns after the first industrial revolution. Coal reserves are abundant, widely distributed, and easy to obtain, but its combustion has a greater impact on the environment. Natural gas is cleaner and has a higher calorific value. It has been one of the main energy sources in industrial society for more than 100 years, and its storage, transportation, and use technologies are very mature.

[0005] Using natural gas to heat the kiln has a fast heating speed and high efficiency, and the cost is about 40% of electric heating at the same calorific value. Although the current natural gas combustion heating technology is relatively mature, it still cannot meet the use requirements in occasions where high temperature control accuracy is required. For heat treatment or sintering of temperature-sensitive materials, it will lead to problems such as poor product consistency and low production efficiency.

[0006] In view of the problems existing in the electric heating and natural gas heating methods in the existing kiln heating technology, a heating kiln is needed that can fully utilize their respective advantages and effectively solve these problems at the same time. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a continuous heating kiln with fast heating speed, high efficiency, uniform temperature in the furnace, high temperature control accuracy and low cost.

[0008] In order to solve the above technical problems, the technical solution proposed by the present invention is: A continuous heating kiln includes a furnace body, a gas combustion system and an electric heating system, the gas combustion system includes a hot gas heating pipeline, the hot gas heating pipeline includes a first hot gas pipeline and a second hot gas pipeline, the first hot gas pipeline is arranged at the upper and lower sides of the furnace body, the second hot gas pipeline is arranged at the left and right sides of the furnace body along the kiln conveying direction, and the electric heating system includes an electric heating element for heating compensation and temperature adjustment, the electric heating element is arranged at the upper and lower sides or / and the left and right sides of the furnace body. The gas combustion system first provides a basic temperature for the furnace through the hot gas heating pipeline, and after each temperature zone reaches the basic temperature, the electric heating system is started to perform heating compensation and adjustment on each temperature zone to meet the process temperature requirements and temperature uniformity requirements.

[0009] In the above-mentioned continuous heating kiln, preferably, the first hot air pipe and the electric heating element are evenly spaced and alternately arranged. This arrangement can ensure that the first hot air pipe and the electric heating element are evenly distributed in the entire kiln heating area, thereby achieving a more uniform heating effect, and secondly, the heat generated by the electric heating element can be more effectively utilized, reducing heat waste, improving overall thermal efficiency, and helping to avoid damage to materials or affecting product quality due to overheating in local areas, ensuring the stability and safety of the heating process.

[0010] In the above continuous heating kiln, preferably, the gas combustion system further includes an air inlet main pipe for conveying hot gas to the hot gas heating pipeline and an air outlet main pipe for outputting the hot gas from the hot gas heating pipeline for heat recovery, and the air inlet main pipe and the air outlet main pipe are arranged outside the furnace body. This arrangement facilitates maintenance and repair of the pipeline, reduces the risk and complexity of entering the furnace body for operation, and helps to quickly locate and deal with leakage or other problems, thereby improving the safety of the entire kiln.

[0011] In the above continuous heating kiln, preferably, an air inlet main pipe and an air outlet main pipe are respectively arranged on the left and right sides of the furnace body, and the adjacent hot gas heating pipes are respectively connected to the air inlet main pipe and the air outlet main pipe. Through this arrangement, the gas flow directions of the two adjacent hot gas heating pipes can be opposite, so that the temperature in the furnace body can be better and more accurately adjusted and the temperature uniformity can be ensured.

[0012] In the above continuous heating kiln, preferably, the electric heating system further comprises a plurality of heating resistors wound around the air inlet main pipe at intervals. This arrangement can accurately assist in heating the hot air entering the furnace body in sections, and heat the area that needs temperature compensation to ensure that the temperature inside the furnace body meets the requirements and ensures temperature uniformity.

[0013] In the above-mentioned continuous heating kiln, preferably, the electric heating system further comprises a temperature sensor for collecting temperature information of each area in the furnace body, and the temperature sensor is electrically connected to the electric heating element and the heating resistance wire through a controller. The temperature sensor can monitor the temperature in the furnace in real time, and the controller adjusts the working state of the electric heating element and the heating resistance wire according to these data to achieve precise temperature control, avoid unnecessary energy consumption, and achieve energy saving.

[0014] In the above continuous heating kiln, preferably, the electric heating element is a continuous heating rod. The continuous heating rod has a wide heating range, a fast heating speed, and can make the temperature in the furnace more uniform.

[0015] In the above-mentioned continuous heating kiln, preferably, the furnace body includes a high temperature zone and a low temperature zone, and the gas combustion device is arranged in the high temperature zone. The gas combustion device is arranged in the high temperature zone where the furnace temperature is high and the heat demand is large, and the hot gas heated in the high temperature zone can be transported to the low temperature zone where the heat demand is small by flowing in the furnace or by setting a hot gas channel, so as to realize the step-by-step utilization of heat.

[0016] In the above continuous heating kiln, preferably, the furnace body includes a furnace shell and a refractory layer, the refractory layer is attached to the inner wall of the furnace shell, and the hot gas heating pipeline is arranged in the refractory layer. This arrangement can make more effective use of space, especially in the case of limited space, it can maximize the utilization efficiency of the area, and the refractory layer has a certain temperature uniformity effect, which can further improve the uniformity of the temperature in the furnace.

[0017] In the above continuous heating kiln, preferably, burners or nozzles with control valves are arranged at intervals on the hot gas heating pipeline. This arrangement can make the furnace quickly reach a high temperature in a short time, and if the material to be heated or sintered has high requirements for the atmosphere and cannot be heated by direct combustion or hot gas, the burner or nozzle can be closed by the control valve, and then indirect heating can be achieved through the hot gas heating pipeline, which has wide applicability.

[0018] Compared with the prior art, the advantages of the present invention are: The present invention provides a basic temperature for kiln heating by setting a gas combustion system, and then compensates and accurately controls the temperature in the kiln by setting an electric heating system, thereby simultaneously realizing low-cost rapid heating in the kiln and accurate control of the temperature in the kiln, greatly reducing production costs and extending the service life of electric heating components. It has the advantages of simple control, good control effect, high temperature control accuracy, low cost, easy implementation, and easy modification of existing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic longitudinal cross-sectional view of the kiln of Example 1; Figure 2 is a schematic cross-sectional view of the kiln of Example 1; Figure 3 It is a top cross-sectional schematic diagram of the kiln of Example 1; Figure 4 It is a partial cross-sectional structural schematic diagram of the kiln air inlet main pipe of Example 1; Figure 5 It is a schematic longitudinal cross-sectional view of the kiln of Example 2; Figure 6 This is a schematic diagram of the transverse cross-section of the kiln of Example 2.

[0021] Legend 1. Furnace body; 2. First hot gas pipeline; 3. Second hot gas pipeline; 4. Air inlet main pipe; 5. Air outlet main pipe; 6. Electric heating element; 7. Heating resistance wire; 8. Burner. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0023] It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element, or it can be indirectly fixed, fixed, connected or connected to the other element through other intermediate connectors.

[0024] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0026] Embodiment 1: like Figures 1 to 4 As shown, the continuous heating kiln of this embodiment includes a furnace body 1, a gas combustion system and an electric heating system. The gas combustion system includes a hot gas heating pipe, and the hot gas heating pipe includes a first hot gas pipe 2 and a second hot gas pipe 3. The first hot gas pipe 2 is arranged at the upper and lower sides of the furnace body 1, and the second hot gas pipe 3 is arranged at the left and right sides of the furnace body 1 along the kiln conveying direction. The electric heating system includes an electric heating element 6 for heating compensation and temperature regulation, and the electric heating element 6 is arranged at the upper and lower sides of the furnace body 1.

[0027] In this embodiment, the first hot gas pipes 2 and the electric heating elements 6 are alternately arranged at even intervals.

[0028] like Figure 3 As shown, in this embodiment, the gas combustion system further includes an air inlet main pipe 4 for conveying hot gas to the hot gas heating pipeline and an air outlet main pipe 5 for outputting the hot gas of the hot gas heating pipeline for heat recovery, and the air inlet main pipe 4 and the air outlet main pipe 5 are arranged outside the furnace body 1. The exposed part outside the furnace body 1 can be covered with a heat insulating material to increase the efficiency of heat energy use.

[0029] In this embodiment, an air inlet main pipe 4 and an air outlet main pipe 5 are respectively arranged on the left and right sides of the furnace body 1, and adjacent hot gas heating pipelines are connected to the air inlet main pipe 4 and the air outlet main pipe 5 respectively.

[0030] like Figure 4 As shown, in this embodiment, the electric heating system also includes a plurality of heating resistors 7 wound around the intake main pipe 4 at intervals. The heating resistor 7 can be a spiral heating element wound around the inner wall of the intake main pipe 4. This arrangement can avoid losses associated with external heat transfer and is more energy-efficient.

[0031] In this embodiment, the electric heating system further includes a temperature sensor for collecting temperature information of each area in the furnace body 1 , and the temperature sensor is electrically connected 7 to the electric heating element 6 and the heating resistance wire through the controller.

[0032] In this embodiment, the electric heating element 6 is a continuous heating rod. Each continuous heating rod and the hollow hot gas heating pipe can be installed in a protective sleeve arranged throughout the furnace to prevent the corrosive atmosphere in the furnace from damaging the continuous heating rod and the hot gas heating pipe. The material of the electric heating element 6 can be selected from silicon carbon rods, silicon molybdenum rods, resistance wires, resistance belts, heating tubes, etc. according to different temperature, atmosphere, installation methods, etc.

[0033] In this embodiment, the furnace body 1 includes a high temperature zone and a low temperature zone, and the gas combustion device is arranged in the high temperature zone.

[0034] In this embodiment, the furnace body 1 includes a furnace shell and a refractory layer, the refractory layer is attached to the inner wall of the furnace shell, and the hot gas heating pipeline is arranged in the refractory layer. In other embodiments, the hot gas heating pipeline can be directly arranged to pass through the furnace or expose a part of it in the furnace as needed.

[0035] In this embodiment, the specific steps may be, first, provide a basic temperature for the furnace through the gas combustion system, for example, if a certain temperature zone requires 1000°C, first use gas to heat to 800°C to maintain the temperature, and this 800°C is the basic temperature of the temperature zone, and natural gas is used to heat nitrogen through the air inlet main pipe 4, and then the furnace is heated through the hot gas heating pipeline. Natural gas heats nitrogen and heats it faster, so that the furnace can reach the basic temperature range as soon as possible. After each temperature zone reaches the basic temperature, start the electric heating system, and perform heating compensation adjustment on each temperature zone. First, the temperature is increased to the required temperature through the continuous heating rod, and then the joint control heating resistor 7 is used for auxiliary heating. At the same time, the temperature information fed back by the temperature sensor in the furnace is used to control the heating temperature of the continuous heating rod and the auxiliary heating resistor 7, so that the furnace meets the required temperature.

[0036] In this embodiment, the hot gas heating pipe is made of metal material. In other embodiments, ceramic materials with good thermal conductivity can be selected. The hot gas passing through the gas combustion system can be the combustion product of natural gas after drying, or hot gas heated by other low-cost fuels.

[0037] Embodiment 2: like Figure 5 and Figure 6 As shown, the continuous heating kiln of this embodiment is basically the same as that of Embodiment 1, except that burners 8 with control valves are arranged at intervals on the hot gas heating pipeline.

[0038] In other embodiments, nozzles with control valves may be arranged at intervals on the hot gas heating pipeline, or the burner 8 and the nozzle may be arranged at intervals.

Claims

1. A continuous heating kiln, comprising a furnace body (1), characterized in that: The invention also comprises a gas combustion system and an electric heating system, wherein the gas combustion system comprises a hot gas heating pipeline, wherein the hot gas heating pipeline comprises a first hot gas pipeline (2) and a second hot gas pipeline (3), wherein the first hot gas pipeline (2) is arranged at the upper and lower sides of the furnace body (1), and the second hot gas pipeline (3) is arranged at the left and right sides of the furnace body (1) along the kiln conveying direction, and the electric heating system comprises an electric heating element (6) for heating compensation and temperature adjustment, wherein the electric heating element (6) is arranged at the upper and lower sides or / and the left and right sides of the furnace body (1).

2. The continuous heating kiln according to claim 1, characterized in that: The first hot air pipes (2) and the electric heating elements (6) are arranged alternately and evenly spaced.

3. The continuous heating kiln according to claim 1, characterized in that: The gas combustion system further comprises an air intake main pipe (4) for conveying hot gas to the hot gas heating pipeline and an air outlet main pipe (5) for outputting the hot gas from the hot gas heating pipeline for heat recovery, wherein the air intake main pipe (4) and the air outlet main pipe (5) are arranged outside the furnace body (1).

4. The continuous heating kiln according to claim 3, characterized in that: An air inlet main pipe (4) and an air outlet main pipe (5) are respectively arranged on the left and right sides of the furnace body (1), and the adjacent hot air heating pipes are respectively connected to the air inlet main pipe (4) and the air outlet main pipe (5).

5. The continuous heating kiln according to claim 3, characterized in that: The electric heating system further comprises a plurality of heating resistance wires (7) which are wound around the air intake main pipe (4) at intervals.

6. The continuous heating kiln according to claim 5, characterized in that: The electric heating system further comprises a temperature sensor for collecting temperature information of various areas in the furnace body (1); the temperature sensor is electrically connected to the electric heating element (6) and the heating resistance wire (7) via a controller.

7. The continuous heating kiln according to any one of claims 1 to 6, characterized in that: The electric heating element (6) is a continuous heating rod.

8. The continuous heating furnace according to any one of claims 1 to 6, characterized in that: The furnace body (1) comprises a high temperature zone and a low temperature zone, and the gas combustion device is arranged in the high temperature zone.

9. The continuous heating furnace according to any one of claims 1 to 6, characterized in that: The furnace body (1) comprises a furnace shell and a refractory layer, the refractory layer is attached to the inner wall of the furnace shell, and the hot gas heating pipeline is arranged in the refractory layer.

10. The continuous heating kiln according to any one of claims 1 to 6, characterized in that: Burners (8) or nozzles with control valves are arranged at intervals on the hot gas heating pipeline.

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