CN113701166A

CN113701166A - Plasma furnace and metal-containing waste plasma melting treatment system and method

Info

Publication number: CN113701166A
Application number: CN202111061796.8A
Authority: CN
Inventors: 陈中华; 俞孝冬
Original assignee: Zhongye Environmental Protection Technology Chongqing Co ltd
Current assignee: Zhongye Environmental Protection Technology Chongqing Co ltd
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2021-11-26

Abstract

The invention discloses a plasma furnace and a plasma melting treatment system and method for metal-containing waste; the plasma furnace includes a furnace body, and the furnace body includes a furnace top, a furnace wall and a furnace bottom, and the center of the furnace top is provided with a furnace body. There is a feeding port; a first plasma torch is installed on the top of the furnace, the first plasma torches are evenly distributed with the feeding port as the center, and the first plasma torch is installed downward to the central axis of the furnace body. The angle between the first plasma torch and the vertical direction is 10-60°; the second plasma torch is installed on the furnace wall, the second plasma torches are evenly distributed along the furnace wall, and the second plasma torch points downwards The central axis of the furnace body is installed, and the included angle between the second plasma torch and the horizontal direction is 0-45°. The invention can solve the problem that the unbalanced space temperature field in the plasma furnace affects the heating of materials, and can also solve the problems that the furnace type cannot be enlarged, the processing scale is small, and the single furnace productivity is low.

Description

Plasma furnace and metal-containing waste plasma melting treatment system and method

Technical Field

The invention belongs to the technical field of waste treatment, and particularly relates to a plasma furnace, a plasma fusion treatment system for metal-containing waste and a method.

Background

Metal-containing wastes are widespread, among which the metal-containing wastes generated due to human production activities are mainly tailings, kiln ashes, electroplating sludge, and the like. The metal-containing waste needs to be treated, the existing method mainly comprises the steps of recycling the metal-containing waste with simple variety, large amount and high market value, and the method mainly comprises the steps of harmless treatment such as landfill or cement kiln cooperation, wherein the variety is numerous and complicated, the mixing is serious, the metal-containing waste contains harmful components, the amount is small, and the market value is low.

In recent years, foreign plasma technology has been introduced or used for domestic reference for the disposal of metal-containing waste. The plasma furnace mainly has two forms, one is a plasma torch furnace and the other is a graphite electrode furnace. The former uses plasma torch to provide heating function similar to burner, the furnace is normally aerobic environment, which is more suitable for organic waste treatment; the whole furnace of the furnace is changed into a torch (a graphite electrode is used as a cathode, an anode is arranged at the bottom of the furnace body, discharge is carried out between the two electrodes, ionized working gas forms plasma), the plasma directly penetrates through materials, the heat transfer efficiency is higher, the heat distribution is more uniform, the atmosphere in the furnace is easier to control, the furnace is more suitable for melting inorganic wastes such as electroplating sludge, incineration ash and the like, the graphite electrode is used as a cathode of a consumable material, and the economic safety is also very good.

In the prior art, the graphite electrode furnace has the following disadvantages: firstly, plasma is generated through discharge between an electrode (cathode) on the top of the furnace and an electrode (anode) on the bottom of the furnace, a high-temperature and high-energy-density core area is only limited to the central part of a plasma arc, materials directly enter the furnace from the vicinity of the electrode on the top of the furnace, and only part of the materials pass through the high-temperature core area and are insufficiently heated in the process of falling to a molten pool; secondly, materials are directly fed from a feeding hole at the top of the furnace, the materials are not dispersed enough, so that the heat absorption area of the materials is not large enough, and the materials do not exchange heat fully before entering a molten pool; thirdly, the temperature distribution of the molten pool is not uniform, and the temperature difference between the middle part and the edge is overlarge; and fourthly, the graphite electrode is consumed along with use, and needs to be replaced after a period of time, so that the cost is increased, and the furnace temperature is fluctuated due to the fact that heat supply is stopped during replacement.

The existing plasma torch furnace is generally a shaft furnace with a large height-diameter ratio, the plasma torch is generally arranged at the lower part of the furnace, the problem that the unbalance of temperature fields of the upper space and the lower space in the furnace affects the heating of materials also exists, and the plasma torch furnace is mainly used for treating organic wastes, provides heat to gasify organic components and melts inorganic components, and generally does not consider the recovery of metals, so the plasma torch furnace is actually a gasification melting plasma furnace; occasionally, the plasma torch furnace with the plasma torches arranged at other positions is low in heat load, the furnace type cannot be large, the processing scale is small, and the single furnace capacity is low because heat required for melting materials is provided by only a limited number of plasma torches. At present, the plasma torch furnace applied to the market is less than 30 tons/day.

Disclosure of Invention

The invention aims to provide a plasma furnace, a metal-containing waste plasma melting treatment system and a metal-containing waste plasma melting treatment method, which can solve the problem that the unbalance of a temperature field of a furnace space influences the heating of materials, and can also solve the problems that a plasma torch furnace cannot be large in size, small in treatment scale and low in single furnace capacity.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention discloses a plasma furnace, which comprises a furnace body, wherein the furnace body comprises a furnace top, a furnace wall and a furnace bottom, and a feed inlet is formed in the center of the furnace top; the furnace top is provided with first plasma torches, the first plasma torches are uniformly distributed by taking the feed port as a center, the first plasma torches are installed downwards to the central axis of the furnace body, and the included angle between the first plasma torches and the vertical direction is 10-60 degrees; the furnace wall is provided with second plasma torches, the second plasma torches are uniformly distributed along the furnace wall, the second plasma torches are installed downwards and point to the central axis of the furnace body, and the included angle between the second plasma torches and the horizontal direction is 0-45 degrees; on the horizontal projection plane of the furnace body, the second plasma torch points to the gap between the adjacent first plasma torches.

Preferably, the number of the first plasma torches is 2 or more, and the number of the second plasma torches is 2 or more.

As a preferred technical solution, the angle of the first plasma torch is adjustable, and the angle of the second plasma torch is adjustable.

As a preferable technical scheme, the plasma furnace also comprises a furnace distributor, and the furnace distributor is suspended at a feed inlet in the furnace body.

According to a preferable technical scheme, the furnace body sequentially comprises a steel shell, a heat insulation material layer and a refractory material layer from outside to inside.

According to the preferable technical scheme, the cross section of the furnace body is circular, and the height-diameter ratio of the furnace body is 0.5-2.

According to a preferable technical scheme, a tail gas outlet is formed in the upper portion of the furnace wall, a molten glass overflow port is formed in the lower portion of the furnace wall, and the second plasma torch is located above the molten glass overflow port; the side of the furnace bottom is provided with a molten metal discharge port, and the middle part of the furnace bottom is provided with a molten liquid discharge port.

The invention also discloses a metal-containing waste plasma melting treatment system, which comprises the plasma furnace, a feeding device and a tail gas combustion chamber, wherein the feeding device comprises a stokehole bin and a screw feeder, the lower part of the stokehole bin is connected with the screw feeder, the screw feeder is connected with a feeding hole of the plasma furnace, and a tail gas outlet of the plasma furnace is connected with the tail gas combustion chamber.

The invention also discloses a method for carrying out plasma fusion treatment on the metal-containing waste by using the metal-containing waste plasma fusion treatment system, which comprises the following steps:

(1) materials including metal-containing waste, fluxing agent and reducing agent are added into a stokehole bin after being mixed, and the materials are conveyed to a feeding hole of a plasma furnace by a screw feeder;

(2) the material receives the heat radiation of the first plasma torch and the second plasma torch in the falling process in the plasma furnace, the material is melted to form molten glass under the action of a fluxing agent, and partial metal ions are reduced to metal simple substances to form alloy under the action of a reducing agent; discharging molten glass obtained from the upper layer at the bottom of the plasma furnace in a continuous overflow mode, and discharging molten metal obtained from the lower layer at the bottom of the plasma furnace in an intermittent mode;

(3) the tail gas of the plasma furnace is discharged to the tail gas combustion chamber from the tail gas outlet, the tail gas is combusted in the tail gas combustion chamber, and the flue gas generated by the tail gas combustion chamber is treated in a rear-sequence flue gas treatment system and is discharged after reaching the standard.

According to the preferable technical scheme, the temperature in the plasma furnace is 1200-1800 ℃, the temperature of a lower molten pool molten layer is 1400-1800 ℃, and the temperature of an upper plasma gas melting space is 1200-1600 ℃; the tail gas is burnt for more than 2s at the temperature of more than 1100 ℃ in the tail gas combustion chamber. The invention has the beneficial effects that:

1. according to the invention, the first plasma torches are uniformly arranged by taking a feed port at the top of the plasma furnace as a center, the second plasma torches are uniformly arranged on the furnace wall, and the first plasma torches and the second plasma torches are designed in a vertically staggered manner, so that the first plasma torches and the second plasma torches both point to scattered materials, and the second plasma torches also point to a molten pool.

2. The feed inlet is arranged in the center of the furnace top, the distributor in the furnace is arranged at the feed inlet, materials are fed into the furnace body from the feed inlet, and the materials are scattered along the distributor in the furnace in the falling process, are fully dispersed, quickly absorb high-temperature heat generated by a plurality of plasma torches, fully absorb heat energy, quickly melt and fall into a molten pool, are fully fused with molten pool melt, and are favorable for complete melting and melt layering (the upper layer is molten glass, and the lower layer is molten metal).

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a schematic longitudinal sectional view of a plasma furnace according to the present invention;

FIG. 2 is a schematic top view of a plasma furnace according to the present invention;

FIG. 3 is a schematic diagram of a plasma fusion processing system of the present invention.

Detailed Description

The present invention is further described with reference to specific examples to enable those skilled in the art to better understand the present invention and to practice the same, but the examples are not intended to limit the present invention.

As shown in fig. 1 and 2, the plasma furnace comprises a furnace body 1, wherein the furnace body 1 comprises a furnace top, a furnace wall and a furnace bottom, a feed inlet 2 is arranged in the center of the furnace top, a tail gas outlet 3 is arranged at the upper part of the furnace wall, a molten glass overflow port 4 is arranged at the lower part of the furnace wall, a molten metal discharge port 5 is arranged on the side surface of the furnace bottom, and a molten metal discharge port 6 is arranged in the middle of the furnace bottom; the furnace top is provided with first plasma torches 7, the first plasma torches 7 are uniformly distributed with the feed port 2 as the center, the first plasma torches 7 point downwards to the central axis of the furnace body 1 and are installed, the included angle between the first plasma torches 7 and the vertical direction is 10-60 degrees, and the angle can be adjusted; the furnace wall is provided with second plasma torches 8, the second plasma torches 8 are uniformly distributed along the furnace wall, the second plasma torches 8 point downwards to the central axis of the furnace body 1 and are arranged, the included angle between the second plasma torches 8 and the horizontal direction is 0-45 degrees, the angle is adjustable, and the second plasma torches 8 are located above the molten glass overflow port 4; on the horizontal projection plane of the furnace body 1, the second plasma torch 8 points to the gap between the adjacent first plasma torches 7.

The number of the first plasma torches 7 is more than 2, and the number of the second plasma torches 8 is more than 2, such as 2, 3, 4, 5, or 6, or even more, respectively, according to the furnace heat load requirement. The first plasma torch 7 and the second plasma torch 8 may not be thermally loaded.

The plasma furnace also comprises a furnace internal distributor 9, wherein the furnace internal distributor 9 is suspended at the feed inlet 2 in the furnace body 1. The distributor 9 in the furnace is generally made of metal or ceramic and can be cooled by water cooling or air cooling.

The plasma furnace is vertically arranged, the furnace body 1 is divided into an upper furnace body and a lower furnace body, the upper furnace body is provided with a top cover, the lower furnace body is provided with a molten pool, and the upper furnace body and the lower furnace body are connected through flanges; the furnace body 1 comprises a steel shell, a heat insulation material layer and a refractory material layer from outside to inside in sequence; the top cover of the furnace body 1 can be of a dome or flat top structure, the molten pool at the bottom of the furnace body 1 can be of a pan bottom or flat bottom structure, the furnace body 1 is generally of a short and fat shape, the cross section of the furnace body 1 is generally circular (or other shapes), and the height-diameter ratio of the furnace body 1 is 0.5-2 (if waste containing more organic components is treated, the height-diameter ratio can be increased again).

A plasma smelting treatment system for metal-containing waste as shown in fig. 3, the plasma smelting treatment system comprises a plasma furnace as defined in claim 7, a feeding device and a tail gas combustion chamber 12, the feeding device comprises a stokehole bin 10 and a screw feeder 11, the screw feeder 11 is connected to the lower part of the stokehole bin 10, the screw feeder 11 is connected to the feeding port 2 of the plasma furnace, and the tail gas outlet 3 of the plasma furnace is connected to the tail gas combustion chamber 12.

The vertical setting of tail gas combustion chamber 12, tail gas combustion chamber 12 is refractory material, heat insulating material, insulation material, steel sheet from inside to outside in proper order, and the steel sheet welds into cylindricly, 12 tops of tail gas combustion chamber are equipped with urgent chimney 13, and upper portion is equipped with exhanst gas outlet 14, be equipped with supplementary combustor, high calorific value waste liquid spray gun and wind spout in the tail

gas combustion chamber

12, 12 bottoms of tail gas combustion chamber are equipped with ash storehouse 15, and the ash sediment can return stokehold feed bin 10 in the ash storehouse 15.

A method of plasma fusion processing metal-containing waste using the metal-containing waste plasma fusion processing system, comprising the steps of:

(1) materials including metal-containing waste, fluxing agent and reducing agent are added into a stokehole bin 10 after being mixed, and the materials are conveyed to a feeding hole 2 of a plasma furnace through a screw feeder 11;

(2) the materials are scattered along a distributor 9 in the furnace in the falling process, are fully dispersed, and quickly absorb the heat radiation of a first plasma torch 7 and a second plasma torch 8, wherein the temperature in the furnace of the plasma furnace is 1200-1800 ℃, the temperature of a molten pool molten layer at the lower part is 1400-1800 ℃, and the temperature of a plasma gas melting space at the upper part is 1200-1600 ℃; melting the materials under the action of a fluxing agent to form molten glass, and reducing partial metal ions into a metal simple substance under the action of a reducing agent to form an alloy; the molten glass obtained at the upper layer of the bottom of the plasma furnace is discharged from a molten glass overflow port 4 in a continuous overflow mode, and the molten metal obtained at the lower layer of the bottom of the plasma furnace is discharged from a molten metal discharge port 5 in a batch mode;

(3) the tail gas of the plasma furnace is discharged from a tail gas outlet 3 to a tail gas combustion chamber 12, the tail gas is combusted in the tail gas combustion chamber 12, the tail gas combustion chamber 12 is burnt by natural gas or other combustion-supporting fuels with peroxide, the temperature is kept above 1100 ℃, under the condition of 3T + E, the tail gas containing small molecular organic matters is fully combusted, the formed flue gas is kept for at least more than 2s before leaving the tail gas combustion chamber 12, the organic matters and dioxin are thoroughly decomposed and incinerated, and the flue gas is further treated by a subsequent flue gas treatment system after leaving a flue gas outlet 14 of the tail gas combustion chamber 12 and then is discharged after reaching the standard.

In the above treatment process, the vitrification process of the metal-containing waste plasma fusion treatment is as follows: qualified incoming metal-containing waste (pre-treatment stage) -molten vitrified product (plasma furnace stage); after the metal-containing waste is vitrified, the obtained glass liquid is water-quenched or air-cooled to form a glass body with better quality, which can easily reach the national standard of vitrified products to be issued, and the alloy metal can be sent to be further refined.

In the treatment process, the fluxing agent can be one or a mixture of sand, lime and bauxite, and the reducing agent can be one or a mixture of coke and waste activated carbon.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims

1. A plasma furnace, characterized in that: the plasma furnace comprises a furnace body, the furnace body comprises a furnace top, a furnace wall and a furnace bottom, and the center of the furnace top is provided with a feeding port; A first plasma torch is installed on it, the first plasma torches are evenly distributed with the feed port as the center, the first plasma torches are installed downwards to the central axis of the furnace body, and the first plasma torches are connected to the vertical The included angle is 10-60°; a second plasma torch is installed on the furnace wall, the second plasma torches are evenly distributed along the furnace wall, and the second plasma torch is installed downward to the central axis of the furnace body. The included angle between the second plasma torch and the horizontal direction is 0-45°; on the horizontal projection plane of the furnace body, the second plasma torch points to the gap between the adjacent first plasma torches.

2 . The plasma furnace according to claim 1 , wherein the number of the first plasma torches is two or more, and the number of the second plasma torches is two or more. 3 .

3 . The plasma furnace according to claim 1 , wherein the angle of the first plasma torch is adjustable, and the angle of the second plasma torch is adjustable. 4 .

4 . The plasma furnace according to claim 1 , wherein the plasma furnace further comprises an in-furnace distributor, and the in-furnace distributor is suspended from the feed inlet in the furnace. 5 .

5 . The plasma furnace according to claim 1 , wherein the furnace body comprises a steel shell, a heat insulating material layer, a heat insulating material layer and a refractory material layer in sequence from the outside to the inside. 6 .

6 . The plasma furnace according to claim 1 , wherein the cross section of the furnace body is circular, and the aspect ratio of the furnace body is 0.5-2. 7 .

7. The plasma furnace according to any one of claims 1 to 6, wherein the upper part of the furnace wall is provided with a tail gas outlet, the lower part of the furnace wall is provided with a molten glass overflow port, and the second The plasma torch is located above the overflow port of molten glass; the side surface of the furnace bottom is provided with a molten metal liquid discharge port, and the middle part of the furnace bottom is provided with a molten liquid discharge port.

8. A plasma melting treatment system for metal-containing waste, characterized in that: the plasma melting treatment system comprises the plasma furnace according to claim 7, a feeding device and an exhaust gas combustion chamber, and the feeding device comprises a furnace Front silo and screw feeder, the lower part of the bunker in front of the furnace is connected to the screw feeder, the screw feeder is connected to the feeding port of the plasma furnace, and the tail gas outlet of the plasma furnace is connected to the tail gas combustion chamber .

9. The method for carrying out plasma melting treatment of metal-containing waste using the metal-containing waste plasma melting treatment system of claim 8, characterized in that: comprising the following steps:

(1) Put the material including metal waste, flux and reducing agent into the silo in front of the furnace after compatibility, and the material is sent to the feeding port of the plasma furnace by the screw feeder;

(2) During the falling process of the material in the plasma furnace, the material receives the heat radiation of the first plasma torch and the second plasma torch. The material is melted under the action of the flux to form glass liquid, and some metal ions are reduced to metal under the action of the reducing agent. Elemental alloys are formed; the molten glass obtained from the upper layer of the plasma furnace is discharged in a continuous overflow mode, and the molten metal obtained from the lower layer of the plasma furnace is discharged intermittently;

(3) The tail gas of the plasma furnace is discharged from the tail gas outlet to the tail gas combustion chamber. The tail gas is burned in the tail gas combustion chamber, and the flue gas generated in the tail gas combustion chamber is processed in the subsequent flue gas treatment system and discharged after reaching the standard.

10 . The method according to claim 9 , wherein the temperature in the plasma furnace is 1200-1800° C., the temperature of the molten layer in the lower molten pool is 1400-1800° C., and the temperature of the upper plasma gas-melting space is 1200-1000° C. 11 . 1600 ℃; the exhaust gas is burned for more than 2s in the exhaust gas combustion chamber above 1100 ℃.