Furnace gas external circulation electromagnetic induction heating large-scale furnace kiln

Abstract

The invention discloses a furnace gas external circulation electromagnetic induction heating large-scale furnace kiln, which adopts a furnace gas external circulation and external electromagnetic induction heating furnace gas mode to improve the heat efficiency of a large-scale electric heating furnace kiln. According to the technical scheme, the large kiln is composed of a kiln body, a temperature control system and an electromagnetic heat supply unit; wherein the electromagnetic heat supply unit forms a furnace gas closed circulation path by a circulating fan, an electromagnetic heater, a heat supply nozzle and a connecting pipeline. The operation process is as follows: the circulating fan extracts gas in the furnace hearth out of the furnace hearth, the gas is sent to the electromagnetic heater outside the furnace body through the connecting pipeline, the electromagnetic heater heats the extracted gas to the temperature required by the process, and the gas is sent back to the furnace hearth through the heat supply nozzle. The invention has the following advantages: 1, heat supply of a large-scale furnace adopts an electromagnetic induction heating technology outside the furnace, so that the maintenance is convenient and fast; workpieces or materials are separated from the heating element, the influence of local high temperature on the workpieces or the materials is reduced, the heating temperature is uniform, and energy is saved.

Description

Technical Field

[0001] The invention relates to the field of electric heating industrial furnaces, and in particular to a large furnace with electromagnetic induction heating using furnace gas external circulation. Background Art

[0002] At present, electric heating industrial furnaces use resistance heating elements or electromagnetic induction heating elements to convert electrical energy into heat to heat workpieces or materials. Resistance heating elements are generally arranged in the same heating space as workpieces or materials. The size of the furnace is not limited, and its overall thermal efficiency is generally 60% to 85%; electromagnetic induction heating is to place the workpiece or material in the middle of the induction heating coil and use the heat energy generated by the change in the direction of the magnetic lines of force to heat the workpiece or material. Due to equipment conditions, electromagnetic induction heating furnaces are generally small in size, but the thermal efficiency can reach more than 88%. It is a technical problem to be solved for large electric heating furnaces to use electromagnetic induction heating to improve thermal efficiency. Summary of the invention

[0003] The invention discloses a large-scale furnace kiln with external circulation of furnace gas and electromagnetic induction heating of furnace gas, which improves the thermal efficiency of the large-scale electric heating furnace kiln by adopting the external circulation of furnace gas and the external electromagnetic induction heating of furnace gas.

[0004] The technical solution of the present invention:

[0005] The large furnace with electromagnetic induction heating of furnace gas external circulation is composed of a furnace body, a temperature control system and an electromagnetic heating unit; the furnace body is composed of a steel structure, refractory materials, and a transmission system, and a furnace is formed in the furnace body; the temperature control system is composed of a furnace temperature detection and control system and a hot air temperature detection and control system; the electromagnetic heating unit is composed of a circulating fan, an electromagnetic heater, a heating nozzle, and connecting pipes, forming a closed circulation passage for furnace gas. According to the heating capacity of the furnace and the process requirements, a number of furnace gas discharge points are set at the upper part of the furnace, and corresponding furnace gas discharge points are set at the lower part, and electromagnetic heaters, furnace gas closed circulation connecting pipes and nozzles are configured between the corresponding upper and lower discharge points and discharge points.

[0006] The operation process of the furnace with external circulation of furnace gas and electromagnetic induction heating is as follows: the circulating fan draws the gas in the furnace out of the furnace and sends it to the electromagnetic heater outside the furnace through the connecting pipeline. The electromagnetic heater heats the drawn gas to the temperature required by the process and sends it back to the furnace through the heating nozzle.

[0007] The present invention has the following advantages:

[0008] 1. Large furnaces and kilns use external electromagnetic induction heating technology for heating, which is convenient for maintenance.

[0009] 2. The workpiece or material is separated from the heating element to reduce the impact of local high temperature on the workpiece or material, and the heating temperature is uniform and energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the cross section of an electromagnetic induction heating furnace with external circulation of furnace gas;

[0011] Figure 2 It is a schematic diagram of the cross-section of an electromagnetic induction baking oven with external circulation of furnace gas.

[0012] Icon description: Steel structure 1, refractory material 2, transmission system 3, furnace temperature detection and control system 4, hot air temperature detection and control system 5, circulating fan 6, electromagnetic heater 7, connecting pipeline 8, heating nozzle 9, supporting frame 10. DETAILED DESCRIPTION

[0013] like Figure 1 As shown, the large furnace kiln heated by electromagnetic induction with external circulation of furnace gas is composed of a furnace body, a temperature control system and an electromagnetic heating unit; the furnace body is composed of a steel structure (1), a refractory material (2), and a transmission system (3); the temperature control system is composed of a furnace temperature detection and control system (4), a hot air temperature detection and control system (5); the electromagnetic heating unit is composed of a circulating fan (6), an electromagnetic heater (7), a connecting pipe (8), and a heating nozzle (9), forming a closed circulation passage for furnace gas; the large furnace kiln heated by electromagnetic induction with external circulation of furnace gas can be used for a variety of high and low temperature furnaces. All calculation formulas and coefficient values ​​in this specific implementation are derived from the "Industrial Furnace Design Manual".

[0014] Calculate the total installed power as shown in Formula 1

[0015] P=kV 2 / 3 —Formula 1

[0016] P-KW installation power

[0017] k-empirical coefficient

[0018] Vm 3 Furnace volume

[0019] Calculate the heating capacity of a single nozzle as shown in Formula 2

[0020] Q=P÷(L÷L1)—Formula 2

[0021] Q-KW single nozzle heating capacity

[0022] P-KW Installation power

[0023] Lm furnace length

[0024] L1-m nozzle air flow channel spacing (0.8m-0.9m)

[0025] Example 1

[0026] like Figure 1As shown, taking a trolley furnace with an effective size of 7m×2m×2m as an example, the furnace temperature is 1000℃ and the furnace gas is circulated externally with electromagnetic induction heating.

[0027] According to formula 1: P = kV 2 / 3

[0028] V = 7m × 2m × 2m = 28m 3 , take k = 80, the total power of the furnace P = 737.67KW,

[0029] According to formula 2: Q = P ÷ (L ÷ L1)

[0030] The nozzles of the eight electromagnetic induction heating units are arranged four on each side of the lower part of the furnace body in a staggered arrangement. The furnace body length L=7m, the air flow channel spacing is 0.9m, the single nozzle heating capacity is 94.84KW, the actual single nozzle heating capacity is 100KW, and the actual total furnace heating power is 800KW.

[0031] In actual use, depending on the furnace temperature uniformity, the eight electromagnetic heating units can work independently or simultaneously, with flexible control and stable operation. The furnace temperature uniformity is within ±10℃, meeting the heating requirements.

[0032] Example 2

[0033] like Figure 2 As shown, a bell-type furnace is used, and the furnace specifications are: the furnace size is 2.48m×0.826m×0.7m, and the furnace temperature is 150℃~600℃, and the furnace gas external circulation electromagnetic induction heating baking oven is used.

[0034] According to formula 1: P = kV 2 / 3

[0035] V=2.48m×0.826m×0.7m=1.4m 3 , take k = 60, the total power of the furnace P = 75.1KW, according to formula 2: Q = P ÷ (L ÷ L1)

[0036] The nozzles of the electromagnetic induction heating unit are staggered at the lower part of both sides of the furnace body. The furnace body length L=2.48m, the air flow channel spacing is 0.8m, the single nozzle heating capacity is 24.2KW, the actual single nozzle heating capacity is 25KW, and the actual total furnace heating power is 75KW.

[0037] In order to ensure the balanced flow of furnace gas, the baking oven adopts three sets of electromagnetic heating units. The materials are placed on the supporting frame (10), and the gas flow space is arranged at the bottom to facilitate the circulation of furnace gas. The furnace temperature uniformity is within ±10°C, which meets the baking temperature requirements.

Claims

1. A furnace kiln with external circulation of furnace gas and electromagnetic induction heating, characterized in that: The furnace is composed of a furnace body, a temperature control system and an electromagnetic heating unit; the furnace body includes a steel structure, refractory materials and a transmission system, and a furnace chamber is formed in the furnace body; the temperature control system includes a furnace chamber temperature detection and control system and a hot air temperature detection and control system; the electromagnetic heating unit includes a circulating fan, an electromagnetic heater, a heating nozzle and connecting pipelines to form a closed circulation passage for furnace gas.

2. The electromagnetic induction heating furnace with external circulation of furnace gas according to claim 1, characterized in that: According to the heating capacity of the furnace and the process requirements, a number of gas discharge points are set at the upper part of the furnace and corresponding gas discharge points are set at the lower part, and electromagnetic heaters, gas closed circulation connecting pipelines and nozzles are arranged between the corresponding upper and lower discharge points and discharge points.

3. The electromagnetic induction heating furnace with external circulation of furnace gas according to claim 1, characterized in that: The operation process of the furnace is as follows: the circulating fan draws the gas in the furnace out of the furnace, and sends it to the electromagnetic heater outside the furnace body through the connecting pipeline. The electromagnetic heater heats the drawn gas to the temperature required by the process, and sends it back to the furnace through the heating nozzle.

4. The electromagnetic induction heating furnace with external circulation of furnace gas according to claim 1, characterized in that: The furnace is a heating furnace with an effective size of 7m×2m×2m and a furnace temperature of 1000°C; According to formula 1: P = kV 2 / 3 V = 7m × 2m × 2m = 28m 3 , take k = 80, the total power of the furnace P = 737.67KW, According to formula 2: Q = P ÷ (L ÷ L1) The nozzles of the eight electromagnetic induction heating units are arranged four on each side of the lower part of the furnace body, in a staggered arrangement, the furnace body length L = 7m, the air flow channel spacing is 0.9m, the single nozzle heating capacity is 94.84KW, the actual single nozzle heating capacity is 100KW, and the actual furnace heating total power is 800KW; In actual use, the eight electromagnetic heating units operate stably and can work independently or simultaneously. The control is flexible and the furnace temperature uniformity is within ±10℃, meeting the heating requirements.

5. The electromagnetic induction heating furnace with external circulation of furnace gas according to claim 1, characterized in that: The furnace is a bell-type furnace with furnace specifications: furnace size 2.48m×0.826m×0.7m, and a baking box with a furnace temperature of 150°C to 600°C; According to formula 1: P = kV 2 / 3 V=2.48m×0.826m×0.7m=1.4m 3 , take k = 60, the total power of the furnace P = 75.1KW, According to formula 2: Q = P ÷ (L ÷ L1) The nozzles of the electromagnetic induction heating unit are arranged alternately at the lower part of both sides of the furnace body. The furnace body length L=2.48m, the air flow channel spacing is 0.8m, the single nozzle heating capacity is 24.2KW, the actual single nozzle heating capacity is 25KW, and the actual furnace heating total power is 75KW; In order to ensure the balanced flow of furnace gas, this baking oven adopts three sets of electromagnetic heating units. The materials are placed on the carrier rack and the gas flow space is arranged at the bottom to facilitate the circulation of furnace gas. The furnace temperature uniformity is within ±10℃, which meets the baking temperature requirements.

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