阅读说明：本技术 等离子体熔融炉及其使用方法 (Plasma melting furnace and method of using the same ) 是由 李磊 李运杰 韦永庆 李亮 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种等离子体熔融炉及其使用方法,其用于焚烧类危险废弃物的处理,等离子体熔融炉包括炉体、炉盖、物料入口、烟气出口、熔融金属排出口、熔融玻璃体排出口、等离子体炬以及石墨电极；炉盖设置在炉体上,炉体和炉盖内部构成炉膛；物料入口和烟气出口都设置在炉盖上；熔融金属排出口设置在炉体的下部；熔融玻璃体排出口设置在炉体上,且位置高于熔融金属排出口；等离子体炬可伸缩地设置在炉盖上,等离子体炬能够深入至炉膛内并向炉膛内喷射等离子高温焰流；石墨电极可伸缩地设置在炉盖上,石墨电极能够深入至炉膛内并在炉膛内产生交流电弧。本发明的等离子体熔融炉可以用于焚烧类危险废弃物的处理,并能大大降低二次废物的生成率。(The invention discloses a plasma melting furnace and a using method thereof, which are used for treating incineration type dangerous wastes, wherein the plasma melting furnace comprises a furnace body, a furnace cover, a material inlet, a smoke outlet, a molten metal discharge port, a molten glass discharge port, a plasma torch and a graphite electrode; the furnace cover is arranged on the furnace body, and the furnace body and the inside of the furnace cover form a hearth; the material inlet and the smoke outlet are both arranged on the furnace cover; the molten metal outlet is arranged at the lower part of the furnace body; the molten glass body outlet is arranged on the furnace body and is higher than the molten metal outlet; the plasma torch is telescopically arranged on the furnace cover and can penetrate into the hearth and jet plasma high-temperature flame flow into the hearth; the graphite electrode is telescopically arranged on the furnace cover and can penetrate into the hearth and generate an alternating current arc in the hearth. The plasma melting furnace can be used for treating incineration type dangerous wastes, and can greatly reduce the generation rate of secondary wastes.)

1. A plasma fusion furnace for the treatment of incineration-like hazardous waste, characterized in that it comprises:

a furnace body;

the furnace cover is arranged on the furnace body, and the furnace body and the inside of the furnace cover form a hearth;

a material inlet arranged on the furnace cover;

a flue gas outlet disposed on the furnace lid;

a molten metal discharge port provided at a lower portion of the furnace body;

a molten glass body discharge port provided in the furnace body and positioned higher than the molten metal discharge port;

the plasma torch is telescopically arranged on the furnace cover and can penetrate into the hearth and jet plasma high-temperature flame flow into the hearth; and

the graphite electrode is telescopically arranged on the furnace cover and can penetrate into the hearth to generate an alternating current arc in the hearth.

2. The plasma-melting furnace as claimed in claim 1, further comprising a pure oxygen blowing means for blowing external oxygen into the inside of said furnace chamber through a pure oxygen blowing port provided at the bottom of said furnace body.

3. A plasma fusion furnace as claimed in claim 1, characterized in that the pure oxygen blowing means is made of a special silicon nitride material.

4. The plasma melting furnace of claim 1 further comprising a temperature sensor disposed at the flue gas outlet, the temperature sensor configured to monitor a flue gas temperature at the flue gas outlet, the temperature sensor in data communication with a feeding device disposed at the material inlet, the feeding device initiating feeding to the material port when the flue gas temperature is above an upper limit of a set range, and the feeding device ceasing feeding to the material port when the flue gas temperature is below a lower limit of the set range.

5. A plasma fusion furnace as in claim 1 further including a layer of corrosion resistant and thermal shock resistant refractory lining the interior walls of the hearth.

6. A method of using the plasma melting furnace of claims 1 to 5, comprising:

a material putting step: starting the feeding device, and feeding the materials subjected to the pretreatment process into the hearth of the plasma melting furnace through the material inlet;

cold starting: the plasma torch extends into the hearth from the top of the hearth, the plasma torch is started to generate plasma high-temperature flame flow to perform high-temperature melting on materials, so that the materials entering the hearth at the initial stage are heated and dissolved, a liquid molten pool is preliminarily formed in the hearth, and the whole hearth is slowly heated;

an electric arc heating step: after a liquid molten pool is formed, the plasma torch withdraws from the top of the hearth, at the moment, the liquid molten pool forms a stable conductive channel, and a graphite electrode is started to generate an alternating current arc to further heat and melt the liquid molten pool; and

material layering step: in the process that the material is heated by plasma high-temperature flame flow and alternating current electric arc, according to the difference of phase properties, the material is layered from top to bottom in the hearth by a scum layer, a molten glass liquid layer and a molten metal layer.

7. The method of using a plasma melting furnace of claim 6, further comprising a periodic tapping step of periodically tapping the glassy liquid of the molten glass liquid layer from the molten glass body tapping port and the liquid metal of the molten metal layer from the molten metal tapping port.

8. The method of claim 6, further comprising a step of controlling the temperature of the exhaust fumes, wherein when the temperature of the exhaust fumes is higher than the upper limit of the set range, the temperature transmitter sends a feeding signal to the feeding device and starts feeding the material inlet to return the temperature of the exhaust fumes to the set range, and when the temperature of the exhaust fumes is lower than the lower limit of the set range, the feeding device stops feeding the material inlet.

9. The method of using a plasma melting furnace according to claim 8, wherein the set range of the exhaust gas temperature is 400 to 500 ℃.

10. The method of using a plasma fusion furnace as defined in claim 6, further comprising a pure oxygen blowing step of blowing external oxygen into the inside of the furnace chamber through a pure oxygen blowing port provided at the bottom of the furnace body, the pure oxygen blowing step supplying oxygen to the pure oxygen blowing port using a pure oxygen blowing means made of a special silicon nitride material.

Technical Field

The invention relates to the field of post-treatment of hazardous wastes, in particular to a plasma melting furnace for treating secondary wastes (fly ash and bottom slag) generated after incineration of hazardous wastes and a using method thereof.

Background

At present, the mainstream method for treating hazardous waste of incineration in China is a rotary kiln, and the kiln has the phenomena of low combustion temperature, high generation rate (generally about 25 percent) of secondary waste (such as fly ash, bottom slag and the like), high dioxin content and the like; these secondary wastes are traditionally produced using either landfill or cement kiln co-ordinated disposal processes. The landfill belongs to a process route which can not be continuously developed due to the scarcity of land resources.

The cement kiln is coordinated to treat more fly ash by adopting a mixing and diluting mode, the treatment temperature is insufficient, harmful substances such as dioxin, heavy metal and the like are not treated fundamentally and still exist in finished cement, the problems of reduced cement grade, insufficient strength and the like are caused in future engineering application of the batch of cement, and the problem of production safety accidents is caused by the fact that the quality of the cement produced by the process does not reach the standard in some areas.

The plasma melting process is taken as a hot spot technology for treating fly ash and bottom slag at present, and has been applied in a large number of attempts in engineering application.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide a plasma melting furnace which is used for treating incineration type dangerous waste and reducing the generation rate of secondary waste.

Another object of the present invention is to provide a method for using a plasma melting furnace, which can efficiently dispose secondary wastes (fly ash and bottom slag) generated after incineration of hazardous wastes, greatly improve the process parameters and safety of the overall incineration hazardous waste disposal system on the basis of thorough harmlessness, and improve the economy and efficiency of the system.

In order to achieve the above object, the present invention provides a plasma melting furnace for treatment of incineration-type hazardous waste, the plasma melting furnace comprising a furnace body, a furnace cover, a material inlet, a flue gas outlet, a molten metal discharge port, a molten glass discharge port, a plasma torch, and a graphite electrode; the furnace cover is arranged on the furnace body, and the furnace body and the inside of the furnace cover form a hearth; the material inlet and the smoke outlet are both arranged on the furnace cover; the molten metal outlet is arranged at the lower part of the furnace body; the molten glass body outlet is arranged on the furnace body and is higher than the molten metal outlet; the plasma torch is telescopically arranged on the furnace cover and can penetrate into the hearth and jet plasma high-temperature flame flow into the hearth; the graphite electrode is telescopically arranged on the furnace cover and can penetrate into the hearth and generate an alternating current arc in the hearth.

In a preferred embodiment, the plasma melting furnace further comprises a pure oxygen blowing device which blows external oxygen into the interior of the furnace chamber through a pure oxygen blowing port provided at the bottom of the furnace body.

In a preferred embodiment, the pure oxygen blowing device is made of a special silicon nitride material.

In a preferred embodiment, the plasma melting furnace further comprises a temperature sensor arranged at the flue gas outlet, the temperature sensor is used for monitoring the smoke exhaust temperature of the flue gas outlet, the temperature sensor is in data connection with a feeding device arranged at the material inlet, when the smoke exhaust temperature is higher than the upper limit of the set range, the feeding device starts feeding materials to the material port, and when the smoke exhaust temperature is lower than the lower limit of the set range, the feeding device stops feeding materials to the material port.

In a preferred embodiment, the plasma melting furnace further comprises a layer of corrosion and thermal shock resistant refractory material lining the inner walls of the hearth.

In order to achieve the other object, the present invention also provides a method for using the plasma melting furnace, which comprises the following steps: a material putting step: starting a feeding device, and feeding the materials subjected to the pretreatment process into a hearth of the plasma melting furnace through a material inlet; cold starting: the plasma torch extends into the hearth from the top of the hearth, the plasma torch is started to generate plasma high-temperature flame flow to perform high-temperature melting on the materials, so that the materials entering the hearth at the initial stage are heated and dissolved, a liquid molten pool is preliminarily formed in the hearth, and the whole hearth is slowly heated; an electric arc heating step: after a liquid molten pool is formed, the plasma torch withdraws from the top of the hearth, at the moment, the liquid molten pool forms a stable conductive channel, and the graphite electrode is started to generate an alternating current arc to further heat and melt the liquid molten pool; and material layering: in the process of heating materials by plasma high-temperature flame flow and alternating current electric arc, the materials are layered from top to bottom in a hearth according to different phase properties.

In a preferred embodiment, the method of using the plasma melting furnace further comprises a periodic discharging step of periodically discharging the glassy liquid of the molten glass liquid layer from the molten glass body discharge port and the liquid metal of the molten metal layer from the molten metal discharge port.

In a preferred embodiment, the use method of the plasma melting furnace further comprises a smoke exhaust temperature control step, when the smoke exhaust temperature is higher than the upper limit of the set range, the temperature transmitter sends a feeding signal to the feeding device and starts feeding to the material outlet so that the smoke exhaust temperature is restored within the set range, and when the smoke exhaust temperature is lower than the lower limit of the set range, the feeding device stops feeding to the material outlet.

In a preferred embodiment, the set range of the exhaust gas temperature is 400-500 ℃.

In a preferred embodiment, the method for using the plasma melting furnace is characterized by further comprising a pure oxygen blowing step of blowing external oxygen into the furnace chamber through a pure oxygen blowing port provided at the bottom of the furnace body, wherein the pure oxygen blowing step uses a pure oxygen blowing device made of a special silicon nitride material to supply oxygen to the pure oxygen blowing port.

Compared with the prior art, the plasma melting furnace and the using method have the following beneficial effects: this scheme adopts cold top technology, with flue gas temperature control at 400 ~ 500 degrees, the flue gas volume only conventional half to two-thirds, promotion equipment security that like this can be very big reduces the flue gas treatment cost. According to the requirements of working conditions, a cold top process is adopted, the input energy and material quantity are reasonably controlled, the upper temperature of the uppermost dross layer is ensured to be kept at a lower temperature all the time, the temperature of a smoke outlet of a melting furnace can be controlled below 500 ℃ (the whole furnace body of the traditional melting furnace is over 1200 ℃, the energy loss is large, and the service life of refractory materials is short), the furnace body temperature of the plasma melting furnace is greatly reduced, the system safety is improved, and the operation and maintenance cost is greatly reduced. By adopting the cold top process, more salt substances, volatile heavy metal mercury, lead and other substances in the treated substances stay in the molten pool and are solidified in the glass body, and more smoke can not enter. The processing pressure of the flue gas system is reduced, and the system cost is reduced. Adopt special pure oxygen to blow in the back with outside oxygen from the bottom of furnace, can be in the inside violent combustion reaction that forms of liquid molten bath, burn totally to unburned carbon to promote the system burn-off rate, the charcoal of burning can also provide the heat, reduces the required energy consumption of heating, and the oxygen blowing in-process forms the inside disturbance of molten bath, can aggravate the heat transfer, makes the inside temperature of molten bath more even, promotes the vitreous body quality of coming out. The plasma torch is used as a heat source device at the initial starting stage, the starting is fast, pollution is avoided, special conductive materials do not need to be added, and the plasma torch is convenient, simple and reliable. When the graphite electrode works stably, the graphite electrode adopts an alternating current arc mode, so that the energy consumption is low, and the temperature of a molten pool is more uniform.

Drawings

FIG. 1 is a schematic view of the equipment layout of a plasma melting furnace according to an embodiment of the present invention;

FIG. 2 is a schematic flow diagram of a treatment process according to one embodiment of the present invention.

Description of the main reference numerals:

1-material inlet; 2-a plasma torch; 3-a graphite electrode; 4-scum layer; 5-molten glass liquid layer; 6-melting the metal layer; 7-molten metal discharge port; 8-a molten glass body discharge port; 9-pure oxygen blowing inlet; 10-a flue gas outlet; 11-furnace cover; 12-a furnace body; 13-corrosion and thermal shock resistant refractory material layer.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

As shown in fig. 1, a plasma melting furnace according to a preferred embodiment of the present invention for treating incinerated hazardous waste mainly comprises a material inlet 1, a plasma torch 2, a graphite electrode 3, a molten metal discharge port 7, a molten glass discharge port 8, a pure oxygen blowing port 9, a flue gas outlet 10, a furnace cover 11, a furnace body 12, a corrosion-resistant thermal shock-resistant refractory material layer 13, and the like. The furnace cover 11 is arranged on the furnace body 12, and the furnace body 12 and the inside of the furnace cover 11 form a hearth; the material inlet 1 and the smoke outlet 10 are both arranged on a furnace cover 11; the molten metal discharge port 7 is provided at the lower part of the furnace body 12; a molten glass discharge port 8 provided in the furnace body 12 and positioned higher than the molten metal discharge port 7; the plasma torch 2 is telescopically arranged on the furnace cover 11, and the plasma torch 2 can penetrate into the hearth and jet plasma high-temperature flame flow into the hearth; the graphite electrode 3 is telescopically arranged on the furnace cover 11, and the graphite electrode 3 can penetrate into a hearth and generate an alternating current arc in the hearth.

In some embodiments, the plasma melting furnace further comprises a pure oxygen blowing device which blows external oxygen into the interior of the furnace chamber through a pure oxygen blowing port 9 provided at the bottom of the furnace body 12. The pure oxygen blowing device is made of special silicon nitride materials.

In some embodiments, the plasma melting furnace further comprises a temperature sensor disposed at the flue gas outlet 10, the temperature sensor is configured to monitor the exhaust gas temperature of the flue gas outlet 10, the temperature sensor is in data connection with a feeding device disposed at the material inlet 1, the feeding device starts to feed the material to the material port when the exhaust gas temperature is higher than the upper limit of the set range, and the feeding device stops to feed the material to the material port when the exhaust gas temperature is lower than the lower limit of the set range.

In some embodiments, the plasma melting furnace further comprises a layer of corrosion and thermal shock resistant refractory material 13 lining the inner walls of the hearth.

As shown in fig. 2. In order to achieve the other purpose, the invention also provides a use method of the plasma melting furnace, which applies the plasma melting furnace to treat incineration type dangerous waste, and the use method comprises the following steps:

a. firstly, hazardous waste (fly ash and bottom slag) passes through a ton bag, is subjected to pretreatment processes such as crushing, magnetic separation and mixing, and then is fed into a hearth of a plasma melting furnace from a material inlet 1 through a feeding device.

b. In the initial stage of cold starting, the plasma torch 2 extends into the hearth from the top of the hearth, and high-temperature melting is carried out on the fed materials by using high-temperature plasma flame flow generated by the torch after starting; so that the materials coming in at the initial stage are heated and dissolved to initially form a liquid molten pool; and the temperature of the whole furnace body 12 is slowly raised.

c. After a liquid molten pool is formed, the plasma torch 2 is withdrawn from the top of the hearth; at the moment, the liquid molten pool forms a stable conductive channel, and the graphite electrode 3 is started to further heat and melt the liquid molten pool; the graphite electrode 3 adopts an alternating current arc mode, so that the temperature in the liquid molten pool is more uniform and stable, and the heat efficiency is high.

d. In the process of melting the object to be treated, depending on the nature of the phase, the object to be treated will form a layer of dross, a layer of molten glass, a layer of molten metal, or the like from top to bottom.

e. After the metal components in the processed object are melted at high temperature, the metal components will sink to form a molten metal layer (the temperature is about 1300-1400 ℃), and the part needs to be periodically emptied from a molten metal outlet 7; the discharged metal substances can be recycled after being collected;

f. the middle part is a molten glass liquid layer, most of nonmetallic components in the processed object are heated and melted to form glassy liquid (qualified glass body is stably formed under the temperature of 1300-1400 ℃), then the liquid is discharged from the position of a molten glass body discharge port 8, and the glass body is formed after water quenching; the part of the glass body can be used as building materials for resource utilization after being tested to be qualified through toxicity and leachability.

g. The cold top technology is adopted; controlling the surface temperature of the layer above the uppermost scum layer through the height of the subsequently added materials, and controlling the upper surface temperature of the scum layer to be 400-500 ℃; the main components of the scum layer are salt-containing substances and newly added materials; after the treated object is heated in the middle-lower high-temperature area, salt substances contained in the treated object are gasified and rise, and are condensed and stay at the lower half part of the scum layer after being contacted with the newly added cold treated object, and meanwhile, the newly added material is heated; after the operation is carried out for a certain time, the furnace is required to be shut down to collect the salt substances, and the salt substances can be recycled.

h. By the layering mode, salt substances in the treated substances are cooled after being heated and stay on the scum layer all the time, so that a large amount of smoke gas cannot enter, and the pressure of the salt substances on a smoke gas system is reduced; similarly, a large amount of volatile heavy metals (mercury, lead and other substances) are also condensed after being heated, most of the volatile heavy metals stay in the scum layer and the molten glass liquid layer, the proportion of the volatile heavy metals entering the flue gas is reduced, the content of the volatile heavy metals in a flue gas system is reduced, and more volatile heavy metals are solidified into the glass body; the pressure of the flue gas system and the system cost are reduced.

i. By adopting the cold top structure, the temperature of the upper surface of the scum layer is controlled to be 400-500 degrees (monitored by the temperature sensor arranged at the smoke outlet 10) through the thickness of the newly added material, the temperature of the smoke outlet 10 is not more than 500 degrees, most of heat is concentrated inside the liquid molten pool (comprising a molten glass liquid layer and a molten metal layer), the energy loss is very small, and the heat efficiency of the system is improved.

j. According to the requirement of the working condition, the input energy (alternating current arc and the like) and the material quantity are controlled, and the flue gas temperature of the flue gas outlet 10 can be controlled within the set range of 400-500 degrees at any time.

k. The bottom of the furnace body 12 is provided with a pure oxygen blowing inlet 9, because bottom slag and fly ash which are discharged after the burning of the rotary kiln at present are not completely combusted and contain a large amount of unburned carbon, which is extremely unfavorable for the formation of the glass body; the pure oxygen blowing device made of special silicon nitride materials is adopted, and after external oxygen is blown from the blowing opening from bottom to top, violent combustion reaction can be formed in the molten pool, so that unburned carbon is burnt completely; thereby improving the burnout rate of the system, providing heat by the burning carbon and reducing the energy consumption required by heating; and moreover, disturbance inside the molten pool is formed in the oxygen blowing process, so that heat exchange can be enhanced, the temperature inside the molten pool is more uniform, and the quality of the glass body is improved.

The inside of the hearth is lined with a special corrosion-resistant thermal shock-resistant refractory material layer 13, which can greatly enhance the corrosion resistance, thermal shock resistance and high temperature resistance of the furnace wall.

After being discharged from the flue gas outlet 10, the flue gas enters a next process flue gas treatment system, and the part is not in the range described in the patent;

in summary, the plasma melting furnace and the using method of the invention have the following advantages: this scheme adopts cold top technology, with flue gas temperature control at 400 ~ 500 degrees, the flue gas volume only conventional half to two-thirds, promotion equipment security that like this can be very big reduces the flue gas treatment cost. According to the requirements of working conditions, a cold top process is adopted, the input energy and material quantity are reasonably controlled, the upper temperature of the uppermost dross layer is ensured to be kept at a lower temperature all the time, the temperature of a smoke outlet of a melting furnace can be controlled below 500 ℃ (the whole furnace body of the traditional melting furnace is over 1200 ℃, the energy loss is large, and the service life of refractory materials is short), the furnace body temperature of the plasma melting furnace is greatly reduced, the system safety is improved, and the operation and maintenance cost is greatly reduced. By adopting the cold top process, more salt substances, volatile heavy metal mercury, lead and other substances in the treated substances stay in the molten pool and are solidified in the glass body, and more smoke can not enter. The processing pressure of the flue gas system is reduced, and the system cost is reduced. Adopt special pure oxygen to blow in the back with outside oxygen from the bottom of furnace, can be in the inside violent combustion reaction that forms of liquid molten bath, burn totally to unburned carbon to promote the system burn-off rate, the charcoal of burning can also provide the heat, reduces the required energy consumption of heating, and the oxygen blowing in-process forms the inside disturbance of molten bath, can aggravate the heat transfer, makes the inside temperature of molten bath more even, promotes the vitreous body quality of coming out. The plasma torch is used as a heat source device at the initial starting stage, the starting is fast, pollution is avoided, special conductive materials do not need to be added, and the plasma torch is convenient, simple and reliable. When the graphite electrode works stably, the graphite electrode adopts an alternating current arc mode, so that the energy consumption is low, and the temperature of a molten pool is more uniform.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.