Waste heat recovery system and method for discharged liquid calcium carbide

Abstract

The invention discloses a discharged liquid calcium carbide waste heat recovery system and a recovery method thereof. The system comprises a calcium carbide furnace, a heat exchange granulator and a waste heat recovery device, the heat exchange granulator comprises a rotary drum, an inner container, a lifting granulation plate, a medium coil pipe and a power device for driving the rotary drum to rotate; an inner container is coaxially and fixedly arranged in the rotary drum, a liquid outlet of the launder is formed in one end in the inner container, and a plurality of material raising and granulating plates are fixed on the inner wall of the inner container; a medium coil pipe is fixedly arranged between the rotary drum and the inner container, and a cold medium outlet of the medium coil pipe is communicated with a heating medium inlet of the waste heat recovery device; the recovery method comprises the following steps: (1) feeding; (2) contact heat exchange; and (3) granulating and exchanging heat. The waste heat recovery system has the beneficial effects that the waste heat recovery system is simple in connecting structure and easy to implement; the liquid calcium carbide is good in waste heat recovery effect and high in recovery rate; the calcium carbide granulation effect is achieved; effective utilization of waste heat is achieved, and the fuel cost of steam production is reduced.

Description

Technical field:

[0001] The patent of this invention belongs to the technical field of waste heat recovery of high-temperature liquid calcium carbide, and specifically relates to a waste heat recovery system and a recovery method of liquid calcium carbide. Background technology:

[0002] Calcium carbide is produced by the endothermic reaction of quicklime (CaO) and carbon (C) in a calcium carbide furnace. After the calcium carbide is produced, it is discharged from the furnace eye of the calcium carbide furnace and flows into the calcium carbide pot. At this time, the calcium carbide is in liquid state with a temperature of about 1800°C. The calcium carbide pot is pulled into the cooling plant by a winch. The cooling plant occupies a large area. The calcium carbide is placed in the cooling plant for 48-72 hours to naturally cool to less than 100°C, and then it is crushed and transported to the downstream process for use. In this process, there is a lot of heat, which is naturally dissipated into the air, resulting in heat waste. In order to solve the above problem, the patent No. CN201811331256.5 discloses a molten calcium carbide one-time cooling granulation molding system and a waste heat recovery method, wherein the molten calcium carbide is first pre-cooled by a calcium carbide granulation device, and the small pieces of calcium carbide formed enter the heat collector and are driven by the radiation recovery module conveyor device. Moving forward, the calcium carbide block with a higher temperature releases all the latent heat and part of the sensible heat of the calcium carbide by radiation heat exchange, and the supercooled water in the cooling water pipe is heated by the above heat and sent to the boiler system of the waste heat recovery device; while the waste heat recovery effect of molten calcium carbide is not good by using the radiation heat exchange method, and the recovery rate can only reach about 30%; the patent with application number CN202111076401.1 discloses a system and method for recovering the heat of liquid calcium carbide from the furnace by absorbing heat from the working fluid, wherein the high-temperature calcium carbide liquid flows out from the calcium carbide furnace into the calcium carbide pot, and the high-temperature flue gas is emitted from the high-temperature calcium carbide liquid and heats the condensate through the smoke hood to realize the recovery of waste heat, but the above patent only realizes the recovery of the heat of the high-temperature flue gas, and does not directly recover the heat of the high-temperature calcium carbide liquid, so the waste heat recovery effect of the high-temperature calcium carbide liquid is not good, and the waste heat recovery rate is low. This paper uses the method of conductive heat recovery to recover this part of the heat more efficiently, while achieving the purpose of calcium carbide granulation. Summary of the invention:

[0003] The first object of the present invention is to provide a liquid calcium carbide waste heat recovery system which has a simple structure, good liquid calcium carbide waste heat recovery effect, and realizes calcium carbide granulation.

[0004] The second object of the present invention is to provide a method for recovering waste heat of liquid calcium carbide discharged from the furnace, which simplifies the process flow and realizes waste heat recovery.

[0005] On the one hand, the technical solution of the present invention discloses a waste heat recovery system for liquid calcium carbide discharged from a furnace, which comprises a calcium carbide furnace, a heat exchange granulator and a waste heat recovery device; the liquid outlet of the calcium carbide furnace is connected to the liquid inlet of the heat exchange granulator through a flow channel; the heat exchange granulator comprises a rotating drum, an inner tank, a material lifting and granulation plate, a medium coil and a power device for driving the rotating drum to rotate; the inner tank is coaxially fixedly arranged in the rotating drum, the liquid outlet of the flow channel is placed at one end of the inner tank, and a plurality of the material lifting and granulation plates are fixed on the inner wall of the inner tank; the medium coil is fixedly arranged between the rotating drum and the inner tank, and the cold medium outlet of the medium coil is connected to the heating medium inlet of the waste heat recovery device.

[0006] Furthermore, the material-lifting and granulating plate is in a triangular shape, and the tip of the material-lifting and granulating plate faces the center of the inner container.

[0007] Furthermore, tugboat assemblies are respectively sleeved on the outer walls of the rotating drum on both sides of the power device, and the power device includes a motor, a gear and a gear ring; the gear sleeve is fixed on the rotating shaft of the motor; the gear ring is sleeved and fixed on the outer wall of the rotating drum, and the outer periphery of the gear ring is provided with meshing teeth that mesh with the gear for transmission.

[0008] Furthermore, a feed hopper is fixedly connected to the feed end of the inner container; the liquid outlet of the flow channel is placed in the small-diameter end of the feed hopper; and the large-diameter end of the feed hopper is connected to the inner container.

[0009] Furthermore, the length of the feed hopper is 1.8m-2.0m, the radius of the small diameter end of the feed hopper is 1.45m-1.55m, the length of the drum is 30m-40m, the diameter of the inner liner is 1.9-2.1m, and the rotation speed of the drum is 5-10 revolutions per minute.

[0010] Furthermore, it also includes a heat transfer oil storage tank, the oil outlet of the heat transfer oil storage tank is connected to the cold medium inlet of the medium coil, and the heating medium outlet of the waste heat recovery device is connected to the oil inlet of the heat transfer oil storage tank.

[0011] Furthermore, the waste heat recovery device includes a waste heat boiler and an emergency cooling device, the cold medium outlet of the medium coil is respectively connected to the heating medium inlet of the waste heat boiler and the emergency cooling device, and the heating medium outlet of the waste heat boiler and the emergency cooling device are both connected to the oil inlet of the heat transfer oil storage tank.

[0012] Another aspect of the present invention also discloses a method for recovering waste heat of liquid calcium carbide discharged from a furnace, which comprises the following steps:

[0013] (1) Feeding: Liquid calcium carbide with a temperature of 1800℃ to 2200℃ from the outlet of the calcium carbide furnace enters the feed hopper of the rotating heat exchange granulator by gravity;

[0014] (2) Contact heat exchange: The liquid calcium carbide in step (1) enters the inner tank and directly contacts the inner wall of the inner tank. The heat transfer oil in the medium coil is heated by metal heat conduction, and the calcium carbide is quickly cooled to below 500°C. After cooling and shrinking, the calcium carbide is peeled off from the inner wall of the inner tank to form calcium carbide blocks;

[0015] (3) Granulation heat exchange: The calcium carbide blocks in step (2) are transferred to the top of the inner tank along with the lifting granulation plate, and then fall to the tip of the lifting granulation plate to be crushed. This process is repeated to form calcium carbide particles. During the crushing process, the calcium carbide continues to exchange heat with the heat transfer oil in the medium coil until the temperature is below 240°C and the material is discharged.

[0016] Furthermore, the heat transfer oil after absorbing heat in step (2) and step (3) is introduced into a waste heat recovery device.

[0017] Advantages of the present invention:

[0018] 1. The waste heat recovery system of the present invention has a simple connection structure and is easy to implement. When high-temperature liquid calcium carbide enters the rotating heat exchange granulator, the liquid calcium carbide directly contacts the inner wall of the inner tank, and the heat transfer oil in the metal heat conduction heating medium coil is absorbed by the heat transfer oil. The waste heat recovery effect of the liquid calcium carbide is good and the recovery rate is high.

[0019] 2. The heat exchange granulator of the waste heat recovery system of the present invention is provided with a material raising granulation plate, which can effectively break up calcium carbide blocks to form calcium carbide granules, thereby achieving the effect of calcium carbide granulation.

[0020] 3. The waste heat recovery device of the waste heat recovery system of the present invention includes a waste heat boiler and an emergency cooling device. The high-temperature heat transfer oil after absorbing the waste heat goes to the waste heat boiler to heat deoxygenated water for steam production, thereby realizing the effective utilization of waste heat and reducing the fuel cost of steam production.

[0021] 4. The method for recovering the waste heat of liquid calcium carbide disclosed in the present invention is simple and effectively realizes the recovery of the waste heat of liquid calcium carbide. At the same time, it realizes the granulation of calcium carbide, and there is no need for subsequent crushing, which simplifies the process flow. Description of the drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of the system according to Embodiment 1 of the present invention.

[0023] Calcium carbide furnace 1, heat exchange granulator 2, rotating drum 21, inner tank 22, material lifting granulation plate 23, medium coil 24, power device 25, motor 251, gear 252, gear ring 253, tugboat assembly 26, feed hopper 27, waste heat recovery device 3, waste heat boiler 31, emergency cooling device 32, thermal oil storage tank 4, flow channel 5. Specific implementation method:

[0024] The present invention will be further described in detail below through embodiments in conjunction with the accompanying drawings.

[0025] Example 1: Figure 1 As shown, a waste heat recovery system for liquid calcium carbide discharged from a furnace comprises a calcium carbide furnace 1, a heat exchange granulator 2, a waste heat recovery device 3 and a heat transfer oil storage tank 4; the liquid outlet of the calcium carbide furnace 1 is connected to the liquid inlet of the heat exchange granulator 2 through a flow channel 5; the heat exchange granulator 2 comprises a rotating drum 21, an inner liner 22, a material lifting and granulation plate 23, a medium coil 24 and a power device 25 for driving the rotating drum 21 to rotate; the inner liner 22 is coaxially fixedly arranged in the rotating drum 21, the liquid outlet of the flow channel 5 is placed at one end of the inner liner 22, and a plurality of The lifting and granulation plate 23 is triangular in shape, with the tip of the lifting and granulation plate 23 facing the center of the inner tank 22, which can effectively break the calcium carbide blocks to form calcium carbide particles, thereby achieving the effect of calcium carbide granulation; a medium coil 24 is fixedly arranged between the rotating drum 21 and the inner tank 22, and the cold medium outlet of the medium coil 24 is connected to the heating medium inlet of the waste heat recovery device 3; the oil outlet of the thermal oil storage tank 4 is connected to the cold medium inlet of the medium coil 24, and the heating medium outlet of the waste heat recovery device 3 is connected to the oil inlet of the thermal oil storage tank 4.

[0026] The waste heat recovery system of the present invention has a simple connection structure and is easy to implement; high-temperature liquid calcium carbide enters the rotating heat exchange granulator 2, and the liquid calcium carbide directly contacts the inner wall of the inner tank 22. The heat transfer oil in the metal heat conduction heating medium coil 24 is absorbed by the heat transfer oil and a large amount of waste heat of the calcium carbide is taken away, so that the waste heat recovery effect of the liquid calcium carbide is good.

[0027] Embodiment 2: It is the same as Embodiment 1 as a whole, except that tugboat assemblies 26 are respectively sleeved on the outer walls of the drum 21 on both sides of the power device 25, and the power device 25 includes a motor 251, a gear 252 and a gear ring 253; the gear 252 is sleeved and fixed on the rotating shaft of the motor 251; the gear ring 253 is sleeved and fixed on the outer wall of the drum 21, and the outer periphery of the gear ring 253 is provided with meshing teeth that mesh with the gear 252 for transmission.

[0028] Example 3: It is the same as Example 2 as a whole, except that a feed hopper 27 is fixedly connected to the feed end of the inner tank 22; the liquid outlet of the flow channel 5 is placed in the small diameter end of the feed hopper 27; the large diameter end of the feed hopper 27 is connected to the inner tank 22, the length of the feed hopper 27 is 1.8m-2.0m, the radius of the small diameter end of the feed hopper 27 is 1.45m-1.55m, the length of the drum 21 is 30m-40m, the radius of the inner tank 22 is 1.9-2.1m, and the rotation speed of the drum 21 is 5-10 revolutions / minute.

[0029] Embodiment 4: It is the same as Embodiment 3 as a whole, except that the waste heat recovery device 3 includes a waste heat boiler 31 and an emergency cooling device 32, the cold medium outlet of the medium coil 24 is respectively connected to the heating medium inlet of the waste heat boiler 31 and the emergency cooling device 32, and the heating medium outlets of the waste heat boiler 31 and the emergency cooling device 32 are both connected to the oil inlet of the thermal oil storage tank 4; the high-temperature thermal oil after absorbing the waste heat goes to the waste heat boiler 31 to heat the deoxygenated water for steam production, thereby realizing the effective utilization of waste heat and reducing the fuel cost of steam production.

[0030] Embodiment 5: A method for recovering waste heat of liquid calcium carbide discharged from a furnace using the recovery system of Embodiment 1, comprising the following steps:

[0031] (1) Feeding: Liquid calcium carbide with a temperature of 1800°C to 2200°C from the outlet of the calcium carbide furnace 1 enters the feed hopper 27 of the rotating heat exchange granulator 2 by gravity;

[0032] (2) Contact heat exchange: The liquid calcium carbide in step (1) enters the inner tank 22 and directly contacts the inner wall of the inner tank 22. The heat transfer oil in the medium coil 24 is heated by metal heat conduction, and the calcium carbide is quickly cooled to below 500°C. After the calcium carbide cools and shrinks, it peels off from the inner wall of the inner tank 22 to form calcium carbide blocks.

[0033] (3) Granulation heat exchange: The calcium carbide blocks in step (2) are transferred to the top of the inner tank 22 along the lifting granulation plate 23, and then fall to the tip of the lifting granulation plate 23 to be crushed. This process is repeated to form calcium carbide particles. During the crushing process, the calcium carbide continues to exchange heat with the heat transfer oil in the medium coil 24 until the temperature is below 240°C and the material is discharged.

[0034] The heat transfer oil after absorbing heat in step (2) and step (3) is introduced into the waste heat boiler 31 of the waste heat recovery device 3 to heat the deoxygenated water to produce steam. When the waste heat boiler 31 fails to work, the heat transfer oil is introduced into the emergency cooling device 32 to cool the heat transfer oil.

[0035] The method for recovering waste heat of liquid calcium carbide disclosed in the present invention is simple, and effectively realizes the recovery of waste heat of liquid calcium carbide, and simultaneously realizes calcium carbide granulation, and no subsequent crushing is required, thus simplifying the process flow.

[0036] The heat recovery rate is calculated according to the equipment parameters of Example 3: The calculation data is based on the current operating data, and the total heat is calculated according to the formula Q = CM (t 1 -t 2 ) calculation, heat transfer coefficient (i.e. heat recovery rate) K = Q△tm / (Ak), heat exchange area Where M = carbide mass (11200 kg), Q = total heat, C = specific heat (the specific heat of carbide is 0.26), t 1 = temperature before heat exchange, t 2 = temperature after heat exchange, K = heat transfer coefficient, k = heat transfer coefficient (the feed hopper is made of copper, and the heat transfer coefficient of copper is 400), △tm = average temperature difference, r 1 = Radius of the small end of the feed hopper, r 2 = Inner liner radius, h 1 = length of feed hopper, h 2 = liner length; after calculation, it is known that the heat recovery rate is more than 85%.

[0037] The above are preferred embodiments of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A waste heat recovery system for liquid calcium carbide discharged from a furnace, characterized in that: It includes a calcium carbide furnace, a heat exchange granulator and a waste heat recovery device; the liquid outlet of the calcium carbide furnace is connected to the liquid inlet of the heat exchange granulator through a flow channel; the heat exchange granulator includes a rotating drum, an inner tank, a material lifting granulation plate, a medium coil and a power device for driving the rotating drum to rotate; the inner tank is coaxially fixedly arranged in the rotating drum, the liquid outlet of the flow channel is placed at one end of the inner tank, and a plurality of the material lifting granulation plates are fixed on the inner wall of the inner tank; the medium coil is fixedly arranged between the rotating drum and the inner tank, and the cold medium outlet of the medium coil is connected to the heating medium inlet of the waste heat recovery device.

2. The waste heat recovery system for liquid calcium carbide discharged from furnace according to claim 1 is characterized in that: The material lifting and granulation plate is in a triangular shape, and the tip of the material lifting and granulation plate faces the center of the inner container.

3. The waste heat recovery system for liquid calcium carbide discharged from furnace according to claim 1 is characterized in that: Tugboat assemblies are respectively sleeved on the outer walls of the rotating drum on both sides of the power device, and the power device includes a motor, a gear and a gear ring; the gear sleeve is fixed on the rotating shaft of the motor; the gear ring is sleeved and fixed on the outer wall of the rotating drum, and the outer periphery of the gear ring is provided with meshing teeth that mesh with the gear for transmission.

4. The waste heat recovery system for liquid calcium carbide discharged from furnace according to claim 1 is characterized in that: A feed hopper is fixedly connected to the feed end of the inner container; the liquid outlet of the flow channel is placed in the small-diameter end of the feed hopper; and the large-diameter end of the feed hopper is connected to the inner container.

5. A waste heat recovery system for liquid calcium carbide discharged from furnace according to claim 4, characterized in that: The length of the feed hopper is 1.8m-2.0m, the radius of the small diameter end of the feed hopper is 1.45m-1.55m, the length of the drum is 30m-40m, the diameter of the inner liner is 1.9-2.1m, and the rotation speed of the drum is 5-10 revolutions per minute.

6. The waste heat recovery system for liquid calcium carbide discharged from furnace according to claim 1 is characterized in that: It also includes a heat transfer oil storage tank, the oil outlet of the heat transfer oil storage tank is connected to the cold medium inlet of the medium coil, and the heating medium outlet of the waste heat recovery device is connected to the oil inlet of the heat transfer oil storage tank.

7. A waste heat recovery system for liquid calcium carbide according to claim 6, characterized in that: The waste heat recovery device includes a waste heat boiler and an emergency cooling device. The cold medium outlet of the medium coil is respectively connected to the heating medium inlet of the waste heat boiler and the emergency cooling device, and the heating medium outlets of the waste heat boiler and the emergency cooling device are both connected to the oil inlet of the heat transfer oil storage tank.

8. A method for recovering waste heat from liquid calcium carbide using the recovery system described in any one of claims 1 to 6, characterized in that: It includes the following steps: (1) Feeding: Liquid calcium carbide with a temperature of 1800℃ to 2200℃ from the outlet of the calcium carbide furnace enters the feed hopper of the rotating heat exchange granulator by gravity; (2) Contact heat exchange: The liquid calcium carbide in step (1) enters the inner tank and directly contacts the inner wall of the inner tank. The heat transfer oil in the medium coil is heated by metal heat conduction, and the calcium carbide is quickly cooled to below 500°C. After cooling and shrinking, the calcium carbide is peeled off from the inner wall of the inner tank to form calcium carbide blocks; (3) Granulation heat exchange: The calcium carbide blocks in step (2) are transferred to the top of the inner tank along with the lifting granulation plate, and then fall to the tip of the lifting granulation plate to be crushed. This process is repeated to form calcium carbide particles. During the crushing process, the calcium carbide continues to exchange heat with the heat transfer oil in the medium coil until the temperature is below 240°C and the material is discharged.

9. A method for recovering waste heat from liquid calcium carbide as claimed in claim 8, characterized in that: The heat transfer oil after absorbing heat in step (2) and step (3) is introduced into the waste heat recovery device.

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