A plasma melting furnace and a solid waste treatment method

Abstract

The present invention relates to the technical field of solid waste treatment melting furnaces, and specifically discloses a plasma melting furnace and a solid waste treatment method. The melting furnace includes a furnace body and a furnace cover. The interior of the furnace body is divided into two melting pools by a partition wall. A melting pool connection passage is provided at the lower end of the partition wall. A feed inlet is provided on the furnace body above the partition wall. Metal discharge outlets and bottom electrodes are provided at the bottoms of both melting pools. Electrodes are provided on the furnace cover directly above the two melting pools. A flow passage is opened at the upper end of the furnace body, and both ends of the flow passage are communicated with the upper ends of the two melting pools. A molten material discharge outlet is opened at the bottom of the flow passage. The present invention organically combines the integrated heating of arc plasma and slag ohmic heating, making full use of the high temperature of the plasma and the characteristics of Joule heat. It can not only make the temperature distribution of the molten material in the melting pool uniform, but also efficiently utilize heat, solving problems such as difficult slag discharge caused by temperature difference and low energy utilization rate.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment melting furnaces, and specifically discloses a plasma melting furnace and a solid waste treatment method. Background Art

[0002] The plasma melting furnace is a core device for melting industrial solid waste. Currently, the plasma melting furnaces used for solid waste treatment in the industry more refer to the furnace type design of electric arc furnaces.

[0003] For example, the invention patent with the application number 200910184971.5 discloses a device and method for treating solid waste by thermal plasma, including a plasma melting pyrolysis furnace, a thermal plasma generating device, a working gas preparation and supply device, a feeding device, a slag discharge and molten metal discharge device, a tail gas purification and treatment system, and a corresponding measurement and control system; this device can completely destroy the toxic and harmful organic components in various solid wastes through the plasma melting pyrolysis furnace, and at the same time basically convert the wastes into useful gases, stable glassy slag without leaching toxicity, and recyclable metal components, effectively realizing the effective treatment of industrial solid waste. However, this traditional plasma melting pyrolysis furnace still has deficiencies: First, when dealing with solid waste mainly composed of non-metals, since the non-molten slag is non-conductive, when using this melting furnace to melt the non-metal-based slag, there will be great problems when encountering emergencies and needing to restart the furnace; Second, even though this melting furnace adopts a circular electric arc furnace structure, the temperature field inside it is also unevenly distributed. Due to the too low temperature at the slag discharge port, the viscosity of the melt is too high and the fluidity becomes poor, which in turn makes slag discharge difficult, and at the same time its treatment scale for solid waste is limited. Based on this, the present application proposes a plasma melting furnace for treating solid waste mainly composed of non-metals, and effectively solves the above problems and deficiencies existing in the traditional plasma melting pyrolysis furnace. Summary of the Invention

[0004] The purpose of the present invention is to provide a plasma melting furnace and a solid waste treatment method to solve the problems such as difficult furnace start-up, large temperature field difference, difficult slag discharge, and insufficient treatment scale when the traditional or existing plasma melting furnace treats solid waste mainly composed of non-metals.

[0005] The present invention is realized through the following technical solutions:

[0006] A plasma melting furnace includes a furnace body and a furnace cover. The interior of the furnace body is divided into two melting pools by a partition wall. A melting pool connection channel for connecting the two melting pools is provided at the lower end of the partition wall. A feed port is provided on the furnace body above the partition wall. Metal discharge ports and bottom electrodes are provided at the bottoms of the two melting pools, and a switch is connected between the two bottom electrodes through a wire. An electrode or an arc plasma torch for generating arc plasma is provided on the furnace cover directly above the two melting pools;

[0007] A flow channel is opened at the upper end of the furnace body. Both ends of the flow channel are connected to the upper ends of the two melting pools. A molten material discharge port is opened at the bottom of the flow channel, and a plug is provided in the molten material discharge port.

[0008] As a further setting of the above solution, an air injection port connected to the melting pool is provided on the side of the furnace body, and a flue gas discharge port is provided on the furnace cover.

[0009] As a further setting of the above solution, the feed port is centered directly above the partition wall, and a dividing block for evenly distributing the materials input into the feed port is provided at the top of the partition wall.

[0010] As a further setting of the above solution, a baffle is provided at the position where the flow channel is connected to the melting pool. The upper end of the baffle is connected to the furnace cover, and a certain distance is left between the lower end and the bottom wall of the flow channel.

[0011] As a further setting of the above solution, the flow channel is in a long strip shape and is separated into two sides by a refractory partition wall in the middle. The molten material discharge port is provided at the turning position of the flow channel.

[0012] As a further setting of the above solution, the turning position of the flow channel is set in a U shape or a semicircle, and the molten material discharge port is provided in the middle of the turning position of the flow channel.

[0013] As a further setting of the above solution, cooling water jackets are provided around both of the electrodes or the arc plasma torches for generating arc plasma.

[0014] The present invention also discloses a solid waste treatment method using the above plasma melting furnace, including the following steps:

[0015] (1) Cover the bottoms of the two melting pools with a conductive material, and close the switch to connect the circuits of the two bottom electrodes to form a loop;

[0016] (2) Push the two electrodes or the arc plasma torch downward until they contact the conductive material. Then turn on the power supply of the electrode or the arc plasma torch and slowly lift it upward to form a plasma arc to heat the conductive material and melt it into a molten liquid. Then disconnect the bottom electrode circuit to make the current of the molten liquid in the two molten pools conduct through the molten pool connection channel;

[0017] (3) Uniformly input the solid waste to be processed into the two molten pools so that it is melted by the heat energy generated by the plasma arc and forms a melt. The melt rises and enters the flow channel. When the flow channel is completely covered with the melt, it will contact the two electrodes or the arc plasma torch to form a circuit. At this time, the input solid waste is first quickly melted by the plasma arc, and then continuously heated and insulated by the Joule heat in the circuit. Then, when the melt in the flow channel reaches a certain amount, open the melt discharge port to discharge the melt;

[0018] (4) As time goes by, the metal layer in the molten pool will rise. At this time, contact the electrode or the arc plasma torch with the bottom of the molten pool, and then slowly lift the electrode or the arc plasma torch upward. Observe the voltage change of the electrode or the arc plasma torch, and calculate the depth of the metal layer in combination with the lifting speed. After the depth of the metal layer reaches the preset value, open the metal discharge port to discharge the metal layer.

[0019] As a further setting of the above solution, it also includes that when an unexpected situation occurs and it is determined that it cannot be solved in a short time, immediately stop feeding the solid waste, and immediately open the metal discharge port to quickly discharge all the molten materials in the molten pool.

[0020] As a further setting of the above solution, when the molten pool in step (3) melts the solid waste, air is continuously input into the molten pool to play a role in stirring and organic matter oxidation.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The plasma melting furnace disclosed by the present invention combines the integrated heating of arc plasma and slag ohm organically, making full use of the high temperature of the plasma and the characteristics of Joule heat. In the prior art, when using plasma to process non-metallic solid waste, more use of Joule heat. In the present invention, after the solid waste enters, it is first melted by the high temperature of the plasma arc, and then enters the molten pool and is affected by Joule heat, maintaining uniform temperature, so as to more effectively utilize energy and reduce energy consumption.

[0023] In the furnace body of the present invention, the molten pool and the flow channel are designed in a stepped manner up and down, which can effectively construct a slag ohmic integrated heating channel artificially, thereby ensuring uniform temperature distribution of the melt inside the molten pool, efficiently utilizing heat, and avoiding temperature differences of the melt inside the molten pool, thus causing problems such as difficult slag discharge and low energy utilization rate.

[0024] When the molten pool in the present invention treats non-metallic solid waste, air is continuously blown in. It can not only effectively incinerate the non-metallic solid waste in the molten pool, release energy to reduce the energy required for its own treatment, but also the blown air can form agitation inside the molten pool, making the temperature inside the molten pool more uniform.

[0025] The plasma melting furnace and its treatment method disclosed by the present invention, through the design of the bottom electrodes at the lower ends of the two molten pools, can quickly start the melting furnace to form a melt inside when treating non-metallic solid waste, and then continuously treat the added solid waste, greatly improving the start-up speed of the entire furnace. At the same time, its internal volume is larger than that of a traditional electric arc furnace, the treatment capacity is effectively improved, and its treatment speed and treatment scale are effectively increased. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a front view internal planar structure schematic diagram of the present invention;

[0028] Figure 2 It is a side view internal planar structure schematic diagram of the present invention;

[0029] Figure 3 It is a top view internal planar structure schematic diagram of the present invention. Detailed Description of the Embodiments

[0030] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0031] It should be noted that, without conflict, the embodiments and features in the embodiments of this application can be combined with each other. The following will refer to the attached Figures 1 to 3 , and will detail this application in combination with the embodiments. Embodiment 1

[0032] Embodiment 1 discloses a plasma melting furnace for processing non-metal-based waste slag melting, including a furnace body 1 and a furnace cover 2. The inside of the furnace body 1 is surrounded by refractory materials to form two mirror-symmetrically arranged melting pools 3, and two electrodes 4 or arc plasma torches capable of generating arc plasma are provided on the furnace cover 2 above each melting pool 3. A metal discharge port 301 is provided at the bottom of each of the two melting pools 3. At the same time, a bottom electrode 5 is provided at the bottom of each of the two melting pools 3, and the two bottom electrodes 5 are connected to a switch 6 through a wire, so that after the switch 6 is closed, the two bottom electrodes 5 can form a circuit.

[0033] A partition wall 7 is provided between the two melting pools 3, and two melting pools are formed through the partition wall 7. Then, a melting pool connection channel 8 connecting the two melting pools 3 is provided at the lower end of the partition wall 7. A feed port 9 is provided at the upper end of the side of the furnace body 1, and the feed port 9 is centered directly above the partition wall 7. Then, a diversion block 10 is provided at the top of the partition wall 7, so that the materials input from the feed port 9 can be evenly distributed into the two melting pools 3 as much as possible under the action of the diversion block 10.

[0034] A flow channel 11 for connecting the upper ends of the two melting pools 3 is provided in the furnace body 1 on the side opposite to the feed port 9, and the cross-section of the flow channel 11 is designed in a U shape. Specifically, when designed, the flow channel 11 is in a long strip shape, and its two sides are separated by a refractory partition wall 12 in the middle to form a U shape. Then, a molten material discharge port 111 is opened at the bottom of the turning position of the flow channel 11, and a plug 13 that can move up and down to block or open the molten material discharge port 111 is provided in the furnace cover 2 directly above the molten material discharge port 111. In Embodiment 1, the turning position of the flow channel 11 can be designed in a U shape or a semicircle, and the molten material discharge port 111 is provided at the middle position thereof.

[0035] In addition, a baffle 14 made of refractory material is provided at the position where the flow channel 11 is connected to the upper end of the melting pool 3. The upper end of the baffle 14 is connected to the furnace cover 2, and its lower end is kept at a certain height from the bottom wall of the flow channel 11. Through the design of the baffle 14, it can intercept the unmolten solid waste on the upper layer of the melting pool 3 and prevent the solid waste from being directly discharged from the molten material discharge port 111 without being treated. At the same time, a flue gas circulation hole is opened at the upper end of the baffle 14, so that the flue gas above the melting pool 3 can enter above the flow channel 11.

[0036] In this Embodiment 1, an air injection port 15 communicating with the molten bath 3 is further provided on the side surface of the furnace body 1 below the flow channel 11. The air injection port 15 is approximately located at the position of 1 / 2 of the depth of the molten bath 3. Air is continuously input into the molten bath 3 through the air injection port 15, so as to stir the molten bath and oxidize a small amount of organic matter. At the same time, a flue gas discharge port 16 is further provided on the furnace cover 2. Through the flue gas discharge port 16, the flue gas generated during the melting process can be discharged directionally, and is discharged after being treated qualified by subsequent flue gas treatment equipment.

[0037] Finally, a cooling water jacket 17 is provided on the periphery of the two electrodes 4 generating arc plasma in this Embodiment 1. Cooling water is continuously introduced when the electrodes 4 operate for a long time to cool the electrodes 4, avoid the high-temperature and high-load operation of the electrodes 4, and improve the service life of the electrodes 4. Embodiment 2

[0038] Embodiment 2 discloses a method for treating solid waste using the plasma melting furnace in Embodiment 1.

[0039] First step, lay conductive materials such as steel plates, scrap iron or coke at the bottom of the two molten baths 3 to cover the bottom electrodes 5, and then close the switch 6 to connect the circuits of the two bottom electrodes 5 to form a loop.

[0040] Second step, push the two electrodes 4 or arc plasma torches generating arc plasma downward to make them contact the conductive materials laid at the bottom of the molten bath 3, then turn on the power supply of the electrodes 4 or arc plasma torches, and then slowly lift the two electrodes 4 or arc plasma torches upward to form a plasma arc to heat the conductive materials at the bottom of the molten bath 3 to melt them into a molten liquid. Finally, disconnect the switch 6 to disconnect the circuit of the bottom electrode 5, and rely on the molten bath connection channel 8 to make the current of the molten liquid in the two molten baths conduct.

[0041] Third step, put the solid waste into the furnace body through the feed port 9, and under the action of the diversion block 10, it is evenly distributed into the two molten baths, and then melted by the heat energy generated by the generated plasma arc. The generated flue gas is discharged from the furnace body through the flue gas discharge port 16 and connected to subsequent flue gas treatment equipment for treatment, and the melt stays in the molten bath 3. In addition, when treating the input solid waste, air can be continuously introduced into the molten bath 3 through the air injection port 15, so as to stir the melt in the molten bath and oxidize a small amount of organic matter at the same time.

[0042] Fourth step, continue to put the solid waste into the two melting pools 3. The liquid level of the melt will rise and enter the flow channel 11. When the melt completely covers the flow channel 11, it will contact the two electrodes 4 or the arc plasma torch to form a circuit. Then the solid waste is first quickly melted by the generated plasma arc, and then continuously kept warm and heated by the Joule heat in the circuit. After a certain amount of melt accumulates in the flow channel 11, lift the plug 13 to open the melt discharge port 111, so that the melt flows out of the furnace body from it.

[0043] Fifth step, as the operation time goes by, the metal layer in the melting pool 3 will slowly rise, thus squeezing the capacity of the melting pool and reducing the processing capacity. At this time, first lower the electrode 4 or the arc plasma torch to make it contact the bottom of the melting pool 3, then slowly lift the electrode 4 or the arc plasma torch upward, and observe the voltage change of the electrode 4 or the arc plasma torch. Combine the lifting speed to calculate the depth of the metal layer. When the depth of the metal layer reaches the preset value (such as more than 1 / 2 of the depth of the melting pool), open the metal discharge port 301 to discharge the metal layer in the melting pool 3. After the metal layer is basically emptied, plug the metal discharge port 301 again.

[0044] In addition, in case of an emergency and it is determined that it cannot be solved in a short time, immediately stop feeding and immediately open the metal discharge port 301 to quickly discharge all the melt in the melting pool to prevent affecting the next furnace start-up.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plasma melting furnace, comprising a furnace body and a furnace cover, characterized in that, The interior of the furnace body is divided into two melting pools by a partition wall. A melting pool connection channel for connecting the two melting pools is provided at the lower end of the partition wall. A feed inlet is provided on the furnace body above the partition wall. Metal discharge outlets and bottom electrodes are provided at the bottoms of the two melting pools, and a switch is connected between the two bottom electrodes through a wire. An electrode or an arc plasma torch for generating arc plasma is provided on the furnace cover directly above the two melting pools; A flow channel is opened at the upper end of the furnace body. Both ends of the flow channel are communicated with the upper ends of the two melting pools. A molten material discharge outlet is opened at the bottom of the flow channel, and a plug is provided in the molten material discharge outlet.

2. The plasma melting furnace according to claim 1, characterized in that, An air injection port communicated with the melting pool is provided on the side of the furnace body, and a flue gas discharge port is provided on the furnace cover.

3. The plasma melting furnace according to claim 1, characterized in that, The feed inlet is centered directly above the partition wall, and a guiding block for evenly distributing the materials input into the feed inlet is provided at the top of the partition wall.

4. The plasma melting furnace according to claim 1, characterized in that, A baffle is provided at the position where the flow channel is communicated with the melting pool. The upper end of the baffle is connected to the furnace cover, and a certain distance is left between the lower end and the bottom wall of the flow channel.

5. The plasma melting furnace according to claim 1, characterized in that, The flow channel is strip-shaped and is separated into two sides by a refractory partition wall arranged in the middle. The molten material discharge outlet is arranged at the turning position of the flow channel.

6. The plasma melting furnace according to claim 5, characterized in that, The turning position of the flow channel is arranged in a U shape or a semicircle, and the molten material discharge outlet is arranged in the middle of the turning position of the flow channel.

7. The plasma melting furnace according to claim 1, characterized in that, Cooling water jackets are arranged around both of the electrodes or the arc plasma torches for generating arc plasma.

8. A solid waste treatment method using the plasma melting furnace according to any one of claims 1-7, characterized in that, It includes the following steps: (1) Cover the bottoms of the two melting pools with conductive materials, and close the switch so that the circuits of the two bottom electrodes are connected to form a loop; (2) Push the two electrodes or arc plasma torches downward until they contact the conductive materials, then turn on the power supply of the electrodes or arc plasma torches, and slowly lift them upward to form a plasma arc to heat the conductive materials to melt them into a molten liquid. Then disconnect the bottom electrode circuit, and make the current of the molten liquid in the two melting pools conduct through the melting pool connection channel; (3) Uniformly input the solid waste to be processed into the two melting pools so that it is melted by the heat energy generated by the plasma arc and forms a molten material. The molten material rises and enters the flow channel. When the flow channel is completely covered with the molten material, it will contact the two electrodes or arc plasma torches to form a loop. At this time, the input solid waste is first quickly melted by the plasma arc, and then continuously heated and insulated by the Joule heat in the loop. Then, when the molten material in the flow channel reaches a certain amount, open the molten material discharge outlet to discharge the molten material; (4) As the operation time goes by, the metal layer in the melting pool will rise. At this time, lower the electrode or arc plasma torch to contact the bottom of the melting pool, and then slowly lift the electrode or arc plasma torch upward. Observe the voltage change of the electrode or arc plasma torch, and calculate the depth of the metal layer in combination with the lifting speed. After the depth of the metal layer reaches the preset value, open the metal discharge outlet to discharge the metal layer.

9. The solid waste treatment method according to claim 8, wherein, It also includes that when an emergency occurs and it is determined that it cannot be solved in a short time, immediately stop feeding the solid waste, and immediately open the metal discharge outlet to quickly discharge all the molten materials in the melting pool.

10. The solid waste treatment method according to claim 8, wherein, When the molten pool in step (3) melts the solid waste, air is continuously input into the molten pool, thereby playing a role in stirring and oxidizing organic substances.

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