CN114704833B

CN114704833B - Method and system for cooperatively treating hazardous waste by rotary kiln-sintering machine

Info

Publication number: CN114704833B
Application number: CN202210552367.9A
Authority: CN
Inventors: 叶恒棣; 颜旭; 李谦; 魏进超; 柴立元; 周浩宇; 沈维民
Original assignee: Central South University; Zhongye Changtian International Engineering Co Ltd
Current assignee: Central South University; Zhongye Changtian International Engineering Co Ltd
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2023-03-10
Anticipated expiration: 2042-05-20
Also published as: CN114704833A; WO2023221337A1

Abstract

A method for co-disposing hazardous waste with a rotary kiln-sintering machine, the method comprising: 1) Pyrolysis: high-volatile hazardous waste enters the rotary kiln from the kiln head, combustion-supporting air enters the rotary kiln from the kiln tail, and the high-volatile hazardous waste is pyrolyzed in the pyrolysis chamber; 2) And (3) incineration: the material residues and pyrolysis gas after pyrolysis enter an incineration chamber, and are mixed with combustion air and combusted; 3) Flue gas circulation: circulating part of the burned flue gas into the rotary kiln from the kiln head; 4) And (3) cooling: cooling the burned hot slag to obtain cold slag; 5) And (3) sintering: distributing the cold slag on a sintering trolley, and igniting and sintering; in the step 3), calculating the proportion of the circulating flue gas amount entering the rotary kiln to the total flue gas amount according to the combustible content and the flue gas temperature in the incinerated flue gas. The invention adopts the technical scheme of the counter-flow rotary kiln-sintering machine, effectively relieves the ring formation and slag bonding phenomenon when the rotary kiln burns the iron-containing solid waste, and realizes the accurate control of the circulating flue gas volume in the rotary kiln.

Description

Method and system for cooperatively treating hazardous waste by rotary kiln-sintering machine

Technical Field

The invention relates to a hazardous waste disposal process, in particular to a method and a system for cooperatively disposing hazardous waste by using a rotary kiln and a sintering machine, and belongs to the technical field of hazardous waste cooperative sintering treatment.

Background

Generally, the rotary incineration kiln can be used for incinerating hazardous wastes and is an important component device of a hazardous waste incineration system. The hazardous waste contains organic matters and has a certain calorific value, so that the hazardous waste is suitable for being treated in an incineration mode, the purpose of reducing the volume of the hazardous waste can be achieved, the heat energy in the waste can be recovered, and the comprehensive utilization of resources is achieved.

The existing hazardous waste incineration rotary kiln is mainly used for incinerating municipal hazardous waste, including organic resin, municipal sludge and the like, but with the requirement of 'solid waste does not leave factory' of steel enterprises improved, part of steel plants begin to build hazardous waste incineration engineering in the plants for incinerating hazardous waste generated by the steel enterprises. But the dangerous waste that iron and steel enterprise produced contains iron content higher, appears slagging scorification easily, the phenomenon of caking, simultaneously, the current municipal administration danger is useless burns the rotary kiln and also has the phenomenon that temperature distribution is inhomogeneous, and incineration efficiency is than low.

In the prior art, the rotary kiln is used for treating municipal hazardous waste and has low iron content. The method generally adopts the hazardous waste incineration and flue gas purification treatment processes of a rotary kiln, a secondary combustion chamber, a waste heat boiler (SNCR denitration), flue gas quenching, dry deacidification (spraying lime hydrate and activated carbon), a cloth bag dust remover, a draught fan, a prewashing tower, a wet washing tower, a flue gas reheater and a chimney. The process mainly aims at fully burning organic matters in the hazardous waste, and adopts incineration equipment as a rotary kiln as shown in figure 1. In the figure, the area I is a kiln head feeding area, the area II is an incineration area, a hazardous waste feeding hole and an air inlet are formed in the kiln head feeding area, and a material outlet is formed in the kiln tail. In practical application, the rotary kiln has an inclination angle of about 5 degrees (the left is higher than the right in figure 1), so that the material and air enter the rotary kiln from the kiln head (zone I) together, under the action of the rotation and the inclination angle of the kiln body, the material moves towards the kiln tail, is mixed with the air and is combusted, and finally, the residue is discharged out of the rotary kiln from the material outlet. At present, residues in the market are directly dropped into a water tank for wet cooling after being discharged out of a rotary kiln, and the cooled residues are fished out and then solidified for landfill.

The main burning temperature of the dangerous waste in the rotary kiln is about 850-950 ℃, the retention time is 30-40 min, and under the condition, the organic matters in the dangerous waste can be fully burned. According to the current standard and environmental evaluation requirements, the ignition loss of the incineration residue must reach below 5%.

In the prior art, the main treatment object of the hazardous waste incineration technology is municipal hazardous waste, however, when the hazardous waste of the steel plant is treated, the iron content in the hazardous waste of the steel plant is high, such as steel rolling oil sludge, the iron content of the steel rolling oil sludge reaches 50% -60%. If the prior art is still adopted to burn the iron-containing oil sludge, the iron element and the metal oxide in the ash form a low-temperature eutectic substance, and slag and ring formation is very easy to occur in the rotary kiln at the burning temperature of 850-950 ℃. The iron-containing residues are agglomerated in large blocks in the rotary kiln, have high strength, cause blockage of the rotary kiln and cannot be normally produced.

All organic matters in the prior art are fully burned in the rotary kiln to release heat, and although the waste incineration disposal line of the rotary kiln is provided with a waste heat boiler to recover waste heat, the heat dissipation of the rotary kiln is large, and the heat utilization rate of the organic matters is low.

In the prior art, incineration residues and fly ash of municipal hazardous wastes usually adopt cement, lime and water for simple and stable solidification and then are safely buried due to the fact that the incineration residues and the fly ash contain high heavy metals and certain dioxin pollutants, and the treatment process is waste of residue resources, particularly high in iron resource content in hazardous wastes of iron and steel plants, high in recovery value, and the iron resources are not effectively recycled. And the landfill also does not completely eliminate the environmental impact, and the risk of secondary pollution still exists.

In addition, aiming at the process of disposing hazardous wastes in the rotary kiln, a technical scheme for accurately controlling the smoke gas volume or the air intake in the rotary kiln is still lacked at present.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method and a system for co-processing hazardous wastes by combustion of a rotary kiln-sintering machine. According to the invention, the rotary kiln can perform forward flow and reverse flow dual purposes aiming at different types of hazardous wastes, and the adaptability of the rotary kiln to different materials is enlarged. When the materials to be treated are high-volatile hazardous wastes, the method for treating the high-volatile hazardous wastes is a method for cooperatively treating hazardous wastes based on a counter-flow rotary kiln-sintering machine. When the material to be treated is low-volatile hazardous waste, the method for treating the low-volatile hazardous waste is a method for treating hazardous waste based on the concurrent rotary kiln-sintering machine. The invention also distributes the incineration residue generated after the hazardous waste is incinerated in the rotary kiln to a sintering machine for disposal, and the residual organic matters in the incineration residue can be utilized in sintering.

The invention also provides a technical scheme of uniformly arranging a plurality of secondary air channels on the kiln head, and the scheme can ensure the air inlet uniformity of the circulating flue gas when the counter-flow rotary kiln is used for treating high-volatile-component hazardous waste, and enhance the gas uniform mixing effect in the kiln, thereby improving the pyrolysis and incineration effect in the kiln. The scheme can also ensure the uniformity of primary air inlet of the kiln head when the downstream rotary kiln is used for treating low-volatile hazardous wastes, enhance the uniformity of contact between gas and materials in the kiln and accelerate combustion reaction.

Based on the technical scheme that a plurality of secondary air channels are uniformly arranged on the kiln head, in the scheme that the counter-flow rotary kiln is used for treating high-volatile hazardous waste, the invention also provides a calculation formula of the proportion of circulating flue gas circulating from the incinerated flue gas to the rotary kiln through the secondary air channels; in the scheme of treating low-volatile hazardous waste in the downstream rotary kiln, the invention also provides a calculation formula of the air volume proportion entering the rotary kiln from the kiln head through the secondary air duct, thereby realizing the accurate control of the circulating flue gas volume or the air intake volume in the rotary kiln.

According to a first embodiment of the present invention, a method for rotary kiln-sinter machine co-disposal of hazardous waste is provided.

A method for rotary kiln-sintering machine cooperative disposal of hazardous waste, the method comprising the steps of:

1) Pyrolysis: high-volatile matter hazardous waste is conveyed into the rotary kiln through a material inlet of the kiln head. Combustion-supporting air enters the rotary kiln through a discharge air duct at the kiln tail and a kiln tail air duct. High-volatile matter hazardous waste firstly enters a pyrolysis chamber of the rotary kiln for drying and pyrolysis. And feeding the material residues and pyrolysis gas after pyrolysis into the incineration chamber.

2) And (3) incineration: the material residue, the pyrolysis gas and the combustion-supporting air are mixed in the incineration chamber and are combusted. And discharging the burned hot slag out of the rotary kiln through a material outlet at the tail of the kiln. The burned flue gas is discharged out of the rotary kiln through the air duct in the kiln, the annular air duct and the primary air duct.

3) Flue gas circulation: and 2) part of the flue gas entering the primary air channel in the step 2) enters the rotary kiln again through a plurality of secondary air channels uniformly distributed on the kiln head, and pyrolysis and incineration processes are completed together with the materials in the rotary kiln.

4) And (3) cooling: in the process of discharging the hot slag out of the rotary kiln in the step 2), the combustion-supporting air entering the discharge air duct firstly cools the hot slag once. Meanwhile, heated combustion air enters the rotary kiln to participate in pyrolysis and incineration of materials. And the hot slag after primary cooling enters a hot slag cooler and exchanges heat with a cooling medium introduced into the hot slag cooler, and cold slag and the heating medium are obtained after heat exchange is finished.

5) And (3) sintering: distributing the cold slag and the sintering raw material obtained in the step 4) on a sintering trolley, and igniting and sintering.

Wherein: in the step 3), a gas analyzer arranged on the primary air channel detects the combustible content in the burned smoke and records the content as C _g % of the amount of the compound (b). Simultaneously obtaining the temperature T of the burned flue gas _g And K. And calculating the ratio Z and% of the flow of the circulating flue gas entering the rotary kiln through the secondary air duct to the total flow of the burned flue gas. Namely, the method comprises the following steps:

in the above formula, the temperature T of the flue gas after incineration is calculated _g The logarithm operation of the difference value with 273K only carries out logarithm processing on the numerical value, and the unit does not participate in formula operationAnd (4) calculating.

The proportion of the flow of the circulating flue gas which enters the rotary kiln again through the secondary air duct to the total flow of the flue gas after burning is controlled to be Z by the air extractor and the air flow control valve.

In the invention, in the step 2), the iron content w,%, of the high-volatile hazardous waste entering the rotary kiln is detected by a material iron content detection device. Controlling the combustion temperature T in the incineration chamber according to the detected iron content of the material ₀ At deg.C. The method specifically comprises the following steps:

when w is more than 50%, T ₀ Is 550-650 ℃.

When w is more than 25% and less than or equal to 50%, T ₀ Is 650-750 ℃.

When w is more than or equal to 5% and less than or equal to 25%, T ₀ Is 750-850 ℃.

When w is less than 5%, T ₀ Is 850-950 ℃.

According to a second embodiment of the present invention, a method for rotary kiln-sinter machine co-disposal of hazardous waste is provided.

a) And conveying the low-volatile hazardous waste into the rotary kiln through a material inlet of the kiln head. Combustion-supporting air enters the rotary kiln through a plurality of secondary air ducts uniformly distributed on the kiln head. Meanwhile, combustion-supporting air also enters the incineration chamber of the rotary kiln through the primary air duct, the annular air duct and the air duct in the kiln. The low-volatile hazardous waste and combustion-supporting air are mixed in the hearth and are combusted.

b) And discharging the burned hot slag out of the rotary kiln through a material outlet at the tail of the kiln. And the burned flue gas is discharged out of the rotary kiln through a discharge air duct and a kiln tail air duct.

c) Conveying the hot slag discharged from the rotary kiln in the step b) to a hot slag cooler, and introducing a cooling medium into the hot slag cooler. And carrying out heat exchange between the hot slag and the cooling medium in the hot slag cooler, and obtaining cold slag and the heating medium after the heat exchange is finished.

d) Distributing the cold slag and the sintering raw material obtained in the step c) on a sintering trolley, and igniting and sintering.

Wherein: in the step a), calculating the proportion L and percent of the air quantity entering the rotary kiln from the kiln head to the total air quantity required by the rotary kiln through the secondary air duct according to the heat value Q and kcal/kg of the materials of the low-volatile-component hazardous waste conveyed to the rotary kiln. Namely, the method comprises the following steps:

it should be noted that, in the above formula calculation, the exponential operation of the calorific value Q of the material entering the rotary kiln only processes the numerical value thereof, and the unit thereof does not participate in the formula operation.

The proportion of the air quantity entering the rotary kiln from the kiln head to the total air quantity required by the rotary kiln through the secondary air duct is controlled to be L by the air exhaust device and the air quantity control valve.

According to a third embodiment of the present invention, a system for rotary kiln-sinter machine co-disposal of hazardous waste is provided.

A system for rotary kiln-sinter co-disposal of hazardous waste for use in the method of the first or second embodiment, the system comprising a rotary kiln and a sinter disposed downstream of the rotary kiln. And a material inlet is formed in the kiln head of the rotary kiln. And a material outlet and a discharge air duct are arranged on the kiln tail of the rotary kiln. The material outlet is positioned at the bottom of the kiln tail. The discharge air duct is positioned at the upper part of the material outlet and is communicated with the material outlet. And the material outlet is connected to the sintering machine. The kiln body of the rotary kiln comprises a furnace lining and a hearth. Along the material trend, the furnace is divided into a pyrolysis chamber and an incineration chamber. And an air duct in the kiln is arranged in the furnace lining corresponding to the pyrolysis chamber. One end of the air duct in the kiln extends into the kiln head, and the other end is communicated with the incineration chamber. An annular air duct is also arranged on the kiln head. The air duct in the kiln is communicated with a primary air duct arranged outside the rotary kiln through an annular air duct. A plurality of secondary air ducts are separated from the primary air duct. And the plurality of secondary air channels penetrate through the kiln head and are communicated with the pyrolysis chamber. The plurality of secondary air channels are uniformly distributed on the kiln head of the rotary kiln.

In the invention, m secondary air ducts are separated from the primary air duct. The m secondary air ducts are annularly distributed around the material inlet. Wherein: m is 2 to 16.

In the invention, n kiln air ducts are arranged in the rotary kiln. The n air ducts in the kiln are uniformly distributed along the circumferential direction of the rotary kiln. Each kiln inner air duct is communicated with an annular air duct arranged at the kiln head. Wherein: n is 2 to 30.

Preferably, m is 4 to 10.

Preferably, n is 3 to 20.

Preferably, the system further comprises a hot slag cooler disposed between the rotary kiln and the sintering machine. The hot slag cooler is provided with a hot slag inlet, a cold slag outlet, a cold medium inlet and a hot medium outlet. And a material outlet of the rotary kiln is connected to a hot slag inlet of the hot slag cooler. And a cold slag outlet of the hot slag cooler is connected to the sintering machine.

In the invention, a three-way valve is arranged at the position on the primary air channel, which is divided into the secondary air channels. An air extractor and an air control valve are arranged on the secondary air duct.

In the invention, the kiln tail of the rotary kiln is also provided with a heat supplementing burner and a kiln tail air duct. The concurrent heating burner and the kiln tail air duct are both arranged in the middle of the kiln tail, namely the concurrent heating burner and the kiln tail air duct are arranged at the position close to the middle of the cross section of the kiln tail, namely the concurrent heating burner and the kiln tail air duct are arranged at the position close to the central axis at the kiln tail.

In the invention, a temperature detection device is arranged in the incineration chamber of the rotary kiln. And a material iron content detection device is arranged at a material inlet of the kiln head. And a gas analyzer is arranged on the primary air duct and close to the annular air duct.

In the prior art, the hazardous waste incineration rotary kiln is mainly used for incinerating municipal hazardous waste including organic resin, municipal sludge and the like, but with the requirement of 'solid waste does not leave factory' of steel enterprises being increased, part of steel plants begin to build hazardous waste incineration projects in the plants for incinerating hazardous waste generated by the steel enterprises. But the dangerous waste that iron and steel enterprise produced contains iron content higher, appears slagging scorification easily, the phenomenon of caking, causes the rotary kiln to block up, and simultaneously, current municipal administration danger is useless burns the rotary kiln and also has the phenomenon that temperature distribution is inhomogeneous, and incineration efficiency is than low. In addition, in the prior art, all organic matters in the hazardous waste are fully incinerated in the rotary kiln to release heat, and although the waste heat recovery is carried out by the waste heat boiler arranged in the dangerous waste incineration disposal line of the rotary kiln, the heat dissipation of the rotary kiln is large, so that the heat utilization rate of the organic matters is low. In addition, because incineration residues and fly ash of municipal hazardous wastes contain high heavy metals and certain dioxin pollutants, cement, lime and water are usually adopted for simple and stable solidification and then are safely buried, the treatment process is waste of residue resources, particularly, the iron resource content in hazardous wastes of steel plants is high, the recovery value is high, and the iron resource is not effectively recycled. And the landfill also does not completely eliminate the environmental impact, and the risk of secondary pollution still exists. In addition, aiming at the process of disposing hazardous wastes in the rotary kiln, a technical scheme for accurately controlling the smoke gas volume or the air intake in the rotary kiln is still lacked at present.

Aiming at the defects in the dangerous waste disposal process in the prior art, the invention provides a method for co-disposing dangerous waste by combustion of a rotary kiln and a sintering machine. When the material to be treated is high-volatile hazardous waste, the method for treating the high-volatile hazardous waste is a method for treating hazardous waste based on the cooperation of a counter-flow rotary kiln and a sintering machine. The high-volatile matter hazardous waste is hazardous waste with the mass percentage content of dry-based volatile matters more than or equal to H%. Wherein: h is 6 to 12, preferably 7 to 10. The method mainly comprises the steps (or working procedures) of pyrolysis, incineration, flue gas circulation, cooling, sintering and the like. Aiming at the problems that the rotary kiln in the prior art basically burns at 850-950 ℃ and the phenomena of slag formation and caking are very easy to occur when the high-iron-content hazardous waste of a steel plant is treated, the method adjusts and controls the temperature in a burning chamber (namely a main burning area) of the rotary kiln according to the iron content of the hazardous waste, so that the hazardous waste is burned under the low-temperature eutectic point, and the ring formation and slag formation phenomena when the rotary kiln burns the iron-content solid waste are effectively relieved.

When the material to be treated is high-volatile hazardous waste (such as iron-containing oil sludge), the rotary kiln can be used as a pyrolysis-incineration two-section type counter-flow rotary kiln, wherein a kiln head, a pyrolysis chamber, an incineration chamber,The kiln tail is correspondingly provided with a feeding section, a material pyrolysis section, a sufficient incineration section and a discharging section. High volatile content hazardous waste is fed into the rotary kiln from a material inlet of the kiln head in a hydraulic push rod or other forms, and combustion-supporting air reversely (opposite to the material direction) enters the rotary kiln from a discharge air duct and a kiln tail air duct of the kiln tail. The high-volatile hazardous waste entering the rotary kiln firstly enters a pyrolysis chamber for drying and pyrolysis. The pyrolysis chamber is an oxygen-deficient, high temperature environment having a temperature of about 200 to 550 c (preferably 300 to 500 c). The heat source of the pyrolysis chamber is mainly the heat exchange of high-temperature flue gas generated in the burning process to the hearth after entering the air duct in the kiln. The high volatile matter hazardous waste is dried and pyrolyzed in the pyrolysis chamber, and the volatile matter in the material is CH ₄ 、H ₂ And CO and other combustible gases are precipitated. The airflow direction of the material pyrolysis section is from the kiln head to the kiln tail, namely, the pyrolyzed material residues and pyrolysis gas enter the full incineration section, and the material residues, the pyrolysis gas and combustion-supporting air entering the incineration chamber are mixed and violently combusted. The burned hot slag is discharged out of the rotary kiln through a material outlet at the tail of the kiln, and the burned flue gas is discharged out of the rotary kiln through an air duct in the kiln, an annular air duct and a primary air duct, and provides heat required by pyrolysis for the pyrolysis chamber in the process.

It is worth noting that the kiln head is provided with the secondary air duct, which has the main functions of: combustible pyrolysis gas (from the kiln head to the kiln tail) pyrolyzed from the pyrolysis chamber is intensively mixed and combusted with mixed gas (from the kiln tail to the kiln head) of air and flue gas from the incineration chamber, but part of the combustible gas is possibly still unburnt and directly brought into an air channel in the kiln, so that the flue gas contains a large amount of combustible substances, and when the flue gas passes through a three-way valve at the connecting position of a primary air channel and a secondary air channel, part of the flue gas is pumped into the secondary air channel by an air pumping device (such as an air pumping pump) and returns to the rotary kiln again for re-reaction. The circulating flue gas also has the following functions: the pyrolysis gas volume that the material pyrolyzed in the pyrolysis chamber produced compares with the mist of flue gas and air that the burning of the material produced in the burning chamber, and the tolerance of pyrolysis gas is very little, and when mixing with the mist of flue gas and air like this, pyrolysis gas velocity of flow undersize, is difficult to reach fine mixing combustion effect, and circulation flue gas mixes with pyrolysis gas can increase the tolerance of pyrolysis gas, increases the kinetic energy that pyrolysis gas moved to kiln tail direction, strengthens the gas mixing effect in the kiln, accelerates combustion reaction. Meanwhile, the circulating flue gas can also provide a part of heat for material pyrolysis.

The applicant of the present invention proposes a prior application entitled "system and method for co-processing hazardous organic waste by temperature-controlled and oxygen-controlled combustion", which aims to alleviate the ring-forming and slag-bonding phenomenon of the rotary kiln when burning the solid waste containing iron organic materials by temperature-controlled and oxygen-controlled combustion. During subsequent research and practical operation, the applicant finds that the solution of the prior application has the following defects:

(1) in the prior application, part of the burned flue gas enters the rotary kiln through the secondary air duct to participate in pyrolysis and burning of materials in consideration of the fact that the burned flue gas contains combustible materials, but the problem of uniformity of air inlet of the circulating flue gas entering the rotary kiln is ignored in the prior application. On the one hand, the inhomogeneous meeting of circulation flue gas inlet leads to the kiln in the temperature distribution inhomogeneous, and then influences the pyrolysis and the efficiency of burning of the interior material of pyrolysis chamber, simultaneously, also can influence circulation flue gas help pyrolysis gas increase to kiln tail direction motion's kinetic energy, improve the effect of the gas flow rate, and then influence the mixing effect of pyrolysis gas and flue gas, air to the effect of burning in the chamber is burned in the influence.

Aiming at the problem, the application provides a technical scheme for arranging a plurality of secondary air channels, and the plurality of secondary air channels are uniformly distributed at the kiln head of the rotary kiln. Generally, the material inlet is arranged in the middle of the cross section of the kiln head (namely, the material inlet is positioned at the kiln head and close to the central axis), and preferably, the plurality of secondary air channels are uniformly distributed annularly around the material inlet. So set up, the circulation flue gas that gets into the rotary kiln through the circulation of secondary wind channel then can get into the pyrolysis chamber of rotary kiln uniformly in, realize the homogeneity of admitting air of circulation flue gas for temperature distribution is even in the kiln, strengthens the gaseous mixing effect in the kiln simultaneously, thereby improves pyrolysis and incineration efficiency, optimizes the pyrolysis and the effect of burning in the kiln.

(2) This application has add the row's material wind channel on the basis of prior application. The discharge air channel is positioned at the upper part of the material outlet and is communicated with the material outlet. The hot slag obtained after the burning procedure is discharged out of the rotary kiln through a material outlet at the kiln tail, and combustion-supporting air entering the rotary kiln from the discharge air duct firstly cools the hot slag in the discharge process of the hot slag, namely the combustion-supporting air is equivalent to primary cooling air of the hot slag. The primary cooling air can also blow the dust in the hot slag into the rotary kiln again, and the dust is discharged and collected through the air duct in the kiln, the annular air duct and the primary air duct, so that the problem of dust overflow at the slag discharge position at the tail of the kiln is solved. Meanwhile, combustion-supporting air heated by the hot slag enters the rotary kiln to participate in pyrolysis and incineration of materials, namely the heated combustion-supporting air is equivalent to incineration air in the kiln, so that the combustion reaction is accelerated, and the combustion-supporting effect is improved.

And the hot slag after the primary cooling of the combustion air entering the discharge air duct enters a hot slag cooler for secondary cooling, and cold slag and hot medium are obtained after the cooling is finished. And then distributing the cold slag to a sintering machine for disposal. The method provided by the invention has the advantages that the organic matters remained in the incineration residues are subjected to cooperative treatment by utilizing the sintering process of an iron and steel plant, so that the iron element in the iron-containing solid waste is effectively recovered, and the heavy metals in the residues are treated by the sintering process, so that the environmental influence and the secondary pollution risk of the solid waste are thoroughly eliminated. Compared with the prior art, the temperature-controlled incineration in the rotary kiln also enables the organic matters in the hazardous waste to be partially preserved and fully utilized in the sintering process, and the heat energy utilization rate is also improved.

In addition, the cooling medium adopted by the hot slag cooler can adopt air or water according to the heat exchange capacity or the actual requirement, if the air is adopted as the cooling medium, cold air enters the hot slag cooler to be changed into hot air, and then the hot air can be sent into the rotary kiln through a kiln tail air duct of the rotary kiln to be used as combustion-supporting air; if water is used as the cooling medium, the heated hot water can also be used as boiler feed water in the plant. Therefore, the heat energy recovery of the hot slag can be realized no matter air or water is used as a cooling medium.

In the present invention, consideration is given to the content of different charged organic materialsThe components and the contents of the volatile matters are different, and the conditions that the volatile matters are combusted in the furnace (namely in the rotary kiln) after entering the furnace are different, so that the content of combustible matters in the burnt smoke can be changed. Theoretically, the higher the combustible content and the higher the temperature in the flue gas are, the higher the combustible content and the higher the temperature are, the value of circulation is only realized, and if the combustible components in the flue gas are not too much and the flue gas temperature is too low, the too large circulation amount of the flue gas only increases the power consumption of a circulating fan and reduces the reactant concentration in the furnace. Therefore, the proportion of the circulating flue gas should be adjusted according to the temperature of the flue gas and the composition of the flue gas. Obtaining combustible substance (H) according to smoke components measured by a gas analyzer arranged on the primary air channel ₂ +CO+CH ₄ ) Content C of _g (the general range is 10-40%) and the flue gas temperature T is obtained at the same time _g (K) In that respect According to the energy conservation theorem and by combining with production practice data fitting, the proportion Z of the circulating flue gas flow entering the rotary kiln through the secondary air duct to the total flue gas flow after burning is obtained by calculating according to the following formula:

and controlling the proportion of the flow of the circulating flue gas which enters the rotary kiln again through the secondary air duct to the total flow of the burned flue gas to be Z by using an air extractor and an air flow control valve.

A group of calculation examples are calculated according to the formula:

C _g	0	10％	20％	30％	40％
						T _gas (K)	298	425	523	689	865
Z	0	0.101	0.247	0.423	0.620

therefore, according to the components and the temperature of the burned flue gas and the production data fitting formula, the proportion of the circulating flue gas is adjusted, so that the accurate control of the amount of the circulating flue gas in the rotary kiln is realized, and the circulating flue gas can be ensured to exert the maximum effect.

In the invention, the iron content w of the high-volatile hazardous waste entering the rotary kiln is detected by an iron content detection device arranged at a material inlet, and the combustion temperature T in the incineration chamber is controlled according to the detected iron content of the material ₀ . The method for adjusting and controlling the combustion temperature in the incineration chamber mainly comprises the steps of controlling the air quantity (namely combustion-supporting air quantity) entering the rotary kiln hearth and the material quantity, and adjusting the heat compensation quantity of the heat compensation burner when necessary. The method specifically comprises the following steps:

when w is more than 50%, T ₀ Is 550-650 ℃.

When w is more than 25% and less than or equal to 50%, T ₀ Is 650-750 ℃.

When w is less than 5%When, T ₀ Is 850-950 ℃.

And then the combustion temperature in the incineration chamber is monitored in real time through a temperature detection device. The detected real-time combustion temperature T in the incineration chamber and the combustion temperature T required to be controlled in the incineration chamber ₀ A comparison is made. If T = T ₀ And at this moment, the incineration process is normally operated, namely the combustion temperature in the current incineration chamber does not need to be adjusted, and the temperature detection device continues to monitor.

If T is less than T ₀ In this case, the temperature in the incineration chamber is low and needs to be raised. If T > T ₀ In this case, the temperature in the incineration chamber is too high, and it is necessary to lower the temperature in the incineration chamber. At the moment, the real-time oxygen content and the real-time combustible component content in the burned flue gas are detected by a gas analyzer, so that the air quantity and the material quantity entering the hearth of the rotary kiln or the heat supplement quantity of the heat supplement burner are adjusted, and finally T = T ₀ 。

According to the temperature adjusting strategy, after the combustion temperature is adjusted according to the iron content of the material, the retention time of the material in the kiln can not be obviously changed theoretically because the rotating speed of the rotary kiln is unchanged. Compared with the prior art, after the combustion temperature is reduced, the situation that hazardous waste residues are insufficiently burned and organic matter remains may occur. In addition, theoretically, the lower the temperature is, the more the organic matters in the residue are left, and the requirement that the burning reduction rate of the residue is less than 5% in the existing incineration technology cannot be met. However, the requirement that the ignition loss of the residues is less than 5% in the prior incineration technology is to solve the current situation that the incineration residues are generally used for safe landfill at present. In the technical scheme, the incineration residue continues to enter a sintering system for disposal, the residual organic matters can be utilized in sintering, and the residue can be utilized in a grading manner according to different residual organic matters in the residue.

Practical experience shows that organic matters in the incineration residue with the incineration temperature of above 850 ℃ basically disappear, and only iron resources in the residue can be sintered and utilized, so that the residue can be called carbon-free residue. The incineration residue with the incineration temperature within 650 ℃ has more organic matter residues and the residual quantity can reach more than 5 percent, and is called high-carbon residue. The incineration residue with the incineration temperature of 650-850 ℃ has relatively reduced organic matter content, is between high-carbon residue and carbon-free residue, and is called low-carbon residue.

That is, the difference of the iron content of the material corresponds to different combustion temperatures, and the different combustion temperatures correspond to different types of residues after the incineration is finished. The method specifically comprises the following steps:

when T is ₀ At 550-650 deg.c, the cold slag obtained after incineration and cooling is high carbon residue.

When T is ₀ And when the temperature is 650-850 ℃, obtaining low-carbon residue from the cold slag after the incineration is finished and the cooling is carried out.

When T is ₀ When the temperature is 850-950 ℃, the cold slag obtained after incineration and cooling is carbon-free residue.

And a lower layer material distributing machine, a middle layer material distributing machine and an upper layer material distributing machine are sequentially arranged above the sintering trolley positioned at the feeding section of the sintering machine along the material trend. Along the running direction of the sintering trolley, the lower stream of the distributing machine is the ignition holding furnace. The lower part of the sintering machine is provided with a main sintering exhaust fan, and a sintering pallet is not shown in the drawing. In the existing sintering production, because of the air draft effect of the main exhaust fan in the advancing process of the sintering trolley, a heat storage effect exists in a lower sintering material layer, namely, the heat distribution is more at the bottom and less at the top, which may result in that the heat of an upper material layer is not enough and more raw materials are available, while the lower material layer is over-melted due to too much heat, and even because of too much lower heat, the grate bars of the trolley may be burnt out.

Based on the sintering principle and practical experience, in the process of utilizing the incineration residues, the carbon-free residues can be placed into the lower-layer material distributor, and the carbon-free residues are laid on the lower layer of the sintering material to play a role in laying a bottom material, so that the heat of the lower layer of the sintering is effectively reduced, and the grate bars of the trolley are protected. The low-carbon residue and the sintering raw material can be uniformly mixed and then placed into a middle-layer distributing machine to generate a co-mineralization effect with the sintering raw material. Can put into upper cloth material machine with high carbon residue, can increase upper heat, and promote the ignition effect. Through such layering cloth, can alleviate the inhomogeneous current situation of heat distribution in the original sintering bed of material, effectively reduce energy resource consumption, reduce sintering return mine. The sintering process of the invention carries out cascade utilization and layered material distribution on the residues after incineration at different temperatures, relieves the heat storage effect of the existing sinter bed, promotes uniform heat sintering and improves the sintering quality.

It should be noted that the counter-flow type burning rotary kiln in the above scheme is directed to high volatile matter and high iron content hazardous waste. However, the system of the invention can be used for two purposes, and is also a set of equipment, and under the condition that the system is not changed, the rotary kiln can also be changed into a downstream rotary kiln aiming at the incineration of low-volatile hazardous wastes. Because the volatile content of the low-volatile-content hazardous waste is not high, if the low-volatile-content hazardous waste is pyrolyzed, the low-volatile-content hazardous waste cannot generate much volatile content, and the meaning of firstly passing through the pyrolysis section is not great. The application range of the system of the invention to the incinerated hazardous waste is enlarged by changing into a forward flow rotary kiln.

When the materials to be treated are low-volatile hazardous wastes, the method for treating the low-volatile hazardous wastes is a method for cooperatively treating hazardous wastes based on a forward-flow rotary kiln-sintering machine. The low-volatile matter hazardous waste is hazardous waste with the mass percentage content of dry-basis volatile matters less than H%. Wherein: h is 6 to 12, preferably 7 to 10. The method does not need a pyrolysis stage of materials, so that the kiln head, the pyrolysis chamber, the incineration chamber and the kiln tail are correspondingly a feeding section, a primary incineration section, a secondary incineration section and a discharging section at the moment, wherein the secondary incineration section is a main combustion area. Correspondingly, the method mainly comprises the steps (or working procedures) of primary incineration, secondary incineration, cooling, sintering and the like.

When low-volatile matter hazardous waste is incinerated, as shown in fig. 6, the primary air duct is changed from the exhaust passage of the incinerated flue gas to a passage through which combustion-supporting air enters the rotary kiln, and the secondary air duct is changed from the circulating flue gas passage to another passage through which combustion-supporting air enters the rotary kiln, and at this time, the source of the combustion-supporting air can still be the heat medium (i.e., hot air or hot air) exhausted from the hot slag cooler. The secondary air duct conveys combustion-supporting air from the kiln head into the rotary kiln, and the primary air duct conveys the combustion-supporting air from the kiln body into the rotary kiln through the annular air duct and the air duct in the kiln. The discharging air duct and the kiln tail air duct are changed into a discharging channel of the burned flue gas from a channel for combustion air to enter the rotary kiln. When the low-volatile matter hazardous waste is treated by adopting the downstream rotary kiln shown in fig. 6, the direction of the flue gas and the air in the primary air duct, the discharge air duct and the kiln tail air duct is only required to be reversed on the basis of the upstream rotary kiln, and the upstream rotary kiln is changed into the downstream rotary kiln (namely the material direction is the same as the direction of combustion air). The low-volatile matter hazardous waste still enters the rotary kiln from a material inlet of the kiln head, primary air enters a pyrolysis cavity of the rotary kiln from a secondary air channel of the kiln head, and the low-volatile matter hazardous waste and combustion-supporting air are incinerated in the pyrolysis cavity for one time. The proportion of the primary air to the theoretical air quantity needed in the kiln is adjusted by an air extractor and an air quantity control valve on the secondary air duct, and the rest air quantity enters the incineration chamber of the kiln body through the primary air duct, the annular air duct and the air duct in the kiln in the form of secondary air for further incineration. The burned residues are discharged from a material outlet at the tail of the kiln and enter a hot slag cooler for cooling, and the burned flue gas is discharged from a discharge air duct and a kiln tail air duct. And conveying the cooled slag to a sintering process for utilization. The functions of other parts in the rotary kiln are consistent with those of the counter-flow rotary kiln, the secondary burning section corresponding to the burning chamber is a main burning area, the temperature of the main burning area can be regulated by regulating the temperature according to the iron content of the materials, and the original temperature regulation rule is still applicable.

In the scheme of disposing low-volatile hazardous waste through the concurrent rotary kiln, the technical scheme of the multiple secondary air ducts is also applicable. Many secondary air channels are at the kiln head evenly distributed of rotary kiln, then can guarantee to get into the intake uniformity of the combustion-supporting air of rotary kiln through the secondary air channel from the kiln head, strengthen the homogeneity of gaseous and material contact in the kiln to make temperature distribution in the kiln even, accelerate combustion reaction, thereby improve the combustion effect of the section of once burning, and then improve holistic danger and useless the processing effect.

In the invention, the forward flow rotary kiln directly uses the original reverse flow rotary kiln to change the direction of air and flue gas, and the forward flow rotary kiln changes the original external heating type flue gas heat exchange pipeline (namely an air channel in the kiln) into a secondary air supply pipeline, thereby realizing the secondary air supply of the kiln body, changing the situation that the original combustion-supporting air enters from the kiln head, leading to the violent combustion of the kiln head and the higher temperature, and leading to the less air at the kiln tail and the lower temperature, namely the secondary air supply of the kiln body reduces the air inlet at the kiln head, reduces the temperature at the kiln head, improves the temperature at the kiln tail, ensures that the temperature distribution of the rotary kiln is more uniform, and is favorable for reducing nitrogen oxides.

Under such conditions, there is a clear advantage over conventional rotary kilns for the incineration of hazardous waste. The heat value of the traditional rotary kiln for the materials fed into the kiln is required to be more than 2000kcal/kg, the rotary kiln is a soaking kiln, and the temperature for thoroughly burning the wastes is guaranteed to be 850-950 ℃. If the calorific value of the material fed into the kiln is too low, such high temperature cannot be maintained, and additional supplementary fuel is required. The invention adopts sectional air intake, the primary burning section after entering the kiln is low-temperature burning, the temperature is 400-600 ℃, the secondary burning section can still maintain 850-950 ℃, or the temperature of the main burning area is adjusted according to the iron content of the material. Because the temperature of the primary incineration section is reduced compared with the prior art, the requirement on the calorific value of the fuel is reduced. The key of the two-stage combustion lies in the distribution of the graded air intake to the air quantity. The proportion of the primary air (air entering from the kiln head) and the secondary air (air entering from the kiln body) to the total air volume is set as L and L', obviously

L+L’＝1。

According to the heat balance calculation of the rotary kiln and the correction of production actual data, the relation between L and the heat value Q (kcal/kg) of materials fed into the kiln is calculated by the following formula:

(wherein Q is more than or equal to 1000 and less than or equal to 2000).

One set of examples obtained from the above formula is:

Q	1000	1200	1500	1800	2000
						L	0.55	0.21	0.11	0.07	0.06

the analysis by combining the formula can show that when the heat value of the kiln feeding material is less than 1000kcal/kg, the adjustment of the proportion of the primary air volume to the total air volume required by the rotary kiln can not meet the requirement of the kiln feeding heat; when the heat value of the materials entering the kiln is more than 2000kcal/kg, the materials entering the kiln can meet the requirement of soaking in the whole kiln without grading air intake.

Therefore, according to the heat value of the materials entering the kiln and the combination of a production data fitting formula, the primary air intake entering the rotary kiln from the kiln head is adjusted, the accurate control of the air intake in the rotary kiln is realized, and the optimal distribution proportion of the primary air volume and the secondary air volume is further achieved; moreover, after the secondary air intake device and the air quantity distribution method are adopted, the requirement of the heat value of the hazardous waste entering the kiln is reduced from the original 2000kcal/kg to 1000kcal/kg, the requirement of the hazardous waste entering the kiln is reduced, the adaptability of raw materials is expanded, and the energy consumption of waste disposal is saved.

Based on the method for the rotary kiln-sintering machine cooperative disposal of the hazardous waste, the invention also provides a system matched with the rotary kiln-sintering machine cooperative disposal of the hazardous waste. The system includes a rotary kiln and a sintering machine disposed downstream of the rotary kiln. The rotary kiln comprises a kiln head, a kiln body and a kiln tail. The kiln head is provided with a material inlet, the kiln body comprises a furnace lining and a hearth, and the kiln tail is provided with a material outlet and a discharge air duct. The material outlet is positioned at the bottom of the kiln tail. The discharging air channel is positioned at the upper part of the material outlet and is communicated with the material outlet. The material outlet is connected to a sintering machine. Along the material course, the furnace is divided into a pyrolysis chamber and an incineration chamber. And an air duct in the kiln is arranged in the furnace lining corresponding to the pyrolysis chamber, one end of the air duct in the kiln extends into the kiln head, and the other end of the air duct in the kiln is communicated with the incineration chamber. An annular air duct is also arranged on the kiln head. The air duct in the kiln is communicated with a primary air duct arranged outside the rotary kiln through an annular air duct. And a secondary air channel is separated from the primary air channel and penetrates through the kiln head to be communicated with the pyrolysis chamber. Wherein: a plurality of secondary air channels are separated from the primary air channel. The plurality of secondary air channels are uniformly distributed on the kiln head of the rotary kiln. In the invention, the rotary kiln can perform concurrent flow and countercurrent flow aiming at different types of hazardous wastes.

When the material to be treated is high volatile matter danger useless (for example, including iron fatlute), the rotary kiln can regard as pyrolysis-two segmentation countercurrent rotary kilns of burning, and kiln head, pyrolysis cavity, burning cavity, kiln tail correspond promptly at this moment and are feeding section, material pyrolysis section, fully burn section, row's material section. High-volatile hazardous waste is sent into the rotary kiln from a material inlet of the kiln head in a hydraulic push rod or other forms, and combustion-supporting air reversely (opposite to the material direction) enters the rotary kiln from the discharge air duct and the kiln tail air duct. The high-volatile hazardous waste entering the rotary kiln firstly enters a pyrolysis chamber for drying and pyrolysis. The airflow direction of the material pyrolysis section is from the kiln head to the kiln tail, namely, the pyrolyzed material residues and pyrolysis gas enter the full incineration section, and the material residues, the pyrolysis gas and combustion-supporting air entering the incineration chamber are mixed and violently combusted. The burned hot slag is discharged out of the rotary kiln through a material outlet at the tail of the kiln, and the burned flue gas is discharged out of the rotary kiln through an air duct in the kiln, an annular air duct and a primary air duct, and provides heat required by pyrolysis for the pyrolysis chamber in the process. The invention arranges a secondary air duct at the kiln head position, and circulates part of the burned flue gas to the rotary kiln for subsequent pyrolysis and burning. The invention also provides a technical scheme that a plurality of secondary air channels are uniformly arranged on the kiln head of the rotary kiln, and preferably, the plurality of secondary air channels are uniformly and annularly distributed around the material inlet. So set up, the circulation flue gas that gets into the rotary kiln through the circulation of secondary wind channel then can get into the pyrolysis chamber of rotary kiln uniformly in, realize the homogeneity of admitting air of circulation flue gas for temperature distribution is even in the kiln, strengthens the gaseous mixing effect in the kiln simultaneously, thereby improves pyrolysis and incineration efficiency, optimizes the pyrolysis and the effect of burning in the kiln.

The invention also adds a discharging air duct on the basis of the prior application. The discharge air channel is positioned at the upper part of the material outlet and is communicated with the material outlet. The hot slag obtained after the burning procedure is discharged out of the rotary kiln through a material outlet at the tail of the kiln, and combustion-supporting air entering the rotary kiln from a discharge air duct firstly cools the hot slag once in the discharge process of the hot slag, namely the combustion-supporting air is equivalent to primary cooling air of the hot slag. The primary cooling air can also blow the dust in the hot slag into the rotary kiln again, and the dust is discharged and collected through the air duct in the kiln, the annular air duct and the primary air duct, so that the problem of dust overflow at the slag discharge position at the tail of the kiln is solved. Meanwhile, combustion-supporting air heated by the hot slag enters the rotary kiln to participate in pyrolysis and incineration of materials, namely the heated combustion-supporting air is equivalent to incineration air in the kiln, so that the combustion reaction is accelerated, and the combustion-supporting effect is improved.

When the material to be treated is low-volatile hazardous waste (such as converter sludge), the rotary kiln can be directly changed into a concurrent rotary kiln without any change. Because the volatile matter of low volatile matter danger useless itself is not high, even also can not produce how much volatile matter through the pyrolysis, therefore the meaning of passing through material pyrolysis section earlier is not big, and kiln head, pyrolysis cavity, incineration chamber, kiln tail correspond promptly and are feeding section, once burn section, secondary and burn section, row's material section this moment, and wherein the secondary burns the section and is the main combustion zone. The low-volatile hazardous waste is fed into the rotary kiln from a material inlet of the kiln head in a hydraulic push rod or other forms, part of combustion-supporting air enters the rotary kiln from a secondary air duct of the kiln head in the same direction (the direction is the same as that of the material), and the rest of combustion-supporting air enters the incineration chamber through the primary air duct, the annular air duct and an air duct in the kiln, namely the rest of combustion-supporting air enters the rotary kiln from the middle of the kiln body. The low-volatile hazardous waste entering the rotary kiln is firstly mixed with combustion-supporting air in a pyrolysis chamber (namely a primary incineration section) and is subjected to primary combustion, and then enters an incineration chamber (namely a secondary incineration section) and is mixed with the combustion-supporting air entering from the kiln body for further combustion. The burned hot slag is discharged out of the rotary kiln through a material outlet at the kiln tail, and the burned smoke is discharged out of the rotary kiln through a discharge air duct and a kiln tail air duct.

Therefore, in the invention, the forward flow rotary kiln can be directly obtained by reversing combustion air and burned flue gas by using the original reverse flow rotary kiln, the original rotary kiln is changed into a forward flow and reverse flow dual-purpose rotary kiln, the forward flow rotary kiln is used for treating low volatile matter hazardous waste, the reverse flow rotary kiln is used for treating high volatile matter hazardous waste, and the adaptability of the rotary kiln to different materials is improved.

The technical scheme of the multiple secondary air ducts provided by the application is also applicable to the scheme of disposing low-volatile hazardous waste through the downstream rotary kiln. Many secondary air channels are at the kiln head evenly distributed of rotary kiln, then can guarantee to get into the intake uniformity of the combustion-supporting air of rotary kiln through the secondary air channel from the kiln head, strengthen the homogeneity of gaseous and material contact in the kiln to make temperature distribution in the kiln even, accelerate combustion reaction, thereby improve the combustion effect of the section of once burning, and then improve holistic danger and useless the processing effect. In the actual production process, the specific number and size of the secondary air ducts are determined according to the flow rate (or air volume) of flue gas and the size of the rotary kiln. In general, the number of secondary air ducts may be 2-16, preferably 4-10, for example 4, 8, 12.

In the present invention, the sintering machine is disposed downstream of the rotary kiln. And a material outlet at the tail of the kiln is connected to a feeding section of the sintering machine. Preferably, a lower layer material distributing machine, a middle layer material distributing machine and an upper layer material distributing machine are sequentially arranged above the sintering trolley positioned at the feeding section of the sintering machine along the material trend (the number of the specific material distributing machines can be set according to the specific sintering process). And a material outlet of the rotary kiln is connected to a lower-layer distributing machine, a middle-layer distributing machine or an upper-layer distributing machine. The method conveys the incineration residues generated after the rotary kiln incinerates the hazardous wastes to a sintering machine for disposal, and selectively distributes the incineration residues to the lower layer, the middle layer or the upper layer of the sintering trolley according to the incineration degree of the hazardous wastes and the residual condition of organic matters in the incineration residues. The incineration residues incinerated in the rotary kiln are cooperatively treated by utilizing the sintering process of a steel plant, so that iron elements in the iron-containing solid waste can be effectively recovered, heavy metals in the residues are treated by the sintering process, and the environmental influence and the secondary pollution risk of the solid waste are thoroughly eliminated. Compared with the prior art, the rotary kiln adopts temperature control and oxygen control incineration, so that organic matters in hazardous waste can be partially stored and fully utilized in a sintering process, and the heat energy utilization rate is improved.

In the invention, because the residue after the incineration of the rotary kiln is treated in a sintering machine in a synergistic way, if the humidity of the residue is too high, the residue can cause great influence on sintering production, and therefore, the residue needs to be dried before being mixed into the sintering. Based on this, the system of the invention also comprises a hot slag cooler arranged between the rotary kiln and the sintering machine (in the scheme of the counter-flow rotary kiln, the hot slag cooler is used for secondary cooling of the hot slag). The hot slag cooler is a dry hot slag cooler, such as a recuperator. The dry hot slag cooler does not increase the humidity of the residue as compared to the conventional wet cooling.

In the invention, a plurality of kiln air ducts are arranged in the rotary kiln, and the plurality of kiln air ducts are uniformly distributed along the circumferential direction of the rotary kiln, namely the plurality of kiln air ducts are uniformly arranged in the rotary kiln in a rotational symmetry manner. Each kiln air duct is communicated with the annular air duct, namely each kiln air duct is communicated with the primary air duct through the annular air duct. In the actual production process, the specific number and size of the air ducts in the kiln are determined according to the flue gas flow (or air volume) and the size of the rotary kiln. Generally, the number of air ducts in the kiln may be between 2 and 30, preferably between 3 and 20, for example 12, 16, 20.

In order to facilitate the discharge of the flue gas burned in the counter-flow rotary kiln through the primary air duct and the circulation of the flue gas into the rotary kiln through the secondary air duct, and to facilitate the transportation of the combustion-supporting air of the forward-flow rotary kiln into the rotary kiln through the primary air duct and the secondary air duct, respectively, a three-way valve is arranged at the position on the primary air duct where the secondary air duct is separated, and an air extraction device (such as an air extraction pump or a circulation fan) and an air flow control valve are arranged on the secondary air duct to control the amount of the flue gas which circularly enters the rotary kiln, and the air extraction device and the air flow control valve in the forward-flow rotary kiln can control the amount of the combustion-supporting air which enters the rotary kiln through the secondary air duct. In the application, a total air extracting device and a total air volume control valve (as shown in fig. 2) are arranged at the position before the secondary air channels are divided into a plurality of secondary air channels, or an air extracting device and an air volume control valve are arranged on each secondary air channel uniformly distributed on the kiln head.

Compared with the prior art, the invention has the following beneficial technical effects:

1. the invention provides a forward flow and reverse flow dual-purpose rotary kiln, which adopts different combustion forms aiming at different raw materials, burns low-volatile hazardous wastes by forward flow and high-volatile hazardous wastes by reverse flow, and enlarges the adaptability of the rotary kiln to different materials.

2. The invention provides a technical scheme of uniformly arranging a plurality of secondary air channels on a kiln head, which can ensure the air inlet uniformity of circulating flue gas when a counter-flow rotary kiln is used for treating high-volatile hazardous waste and enhance the gas uniformly-mixing effect in the kiln, thereby improving the pyrolysis and incineration effects in the kiln; the scheme can also ensure the uniformity of primary air inlet of the kiln head when the downstream rotary kiln is used for treating low-volatile hazardous wastes, enhance the uniformity of contact between gas and materials in the kiln and accelerate combustion reaction.

3. In the invention, the discharge air duct is arranged at the upper part of the material outlet, and combustion-supporting air entering the rotary kiln from the discharge air duct firstly cools the hot slag once in the discharge process of the hot slag, so that the cooling effect of the hot slag is enhanced; the part of combustion-supporting air can also blow the dust in the hot slag into the rotary kiln again, and the dust is discharged and collected through an air duct in the kiln, an annular air duct and a primary air duct, so that the problem of dust overflow at the slag discharge position at the tail of the kiln is solved; meanwhile, combustion-supporting air heated by the hot slag enters the rotary kiln to participate in pyrolysis and incineration of materials, so that the combustion reaction is accelerated, and the combustion-supporting effect is improved.

4. The invention provides a pyrolysis-incineration two-section type countercurrent incineration rotary kiln aiming at the hazardous waste with high volatile components, and the incineration temperature in the rotary kiln is controlled, so that the hazardous waste is incinerated under the low-temperature eutectic point, and the ring formation and slag bonding phenomena when the iron-containing solid waste is incinerated in the rotary kiln are effectively relieved.

5. In the scheme of the counter-flow rotary kiln, the proportion of the circulating flue gas is adjusted according to the components and the temperature of the incinerated flue gas and a production data fitting formula, so that the accurate control of the circulating flue gas amount in the rotary kiln is realized, and the circulating flue gas can be ensured to exert the maximum effect.

6. In the scheme of the concurrent rotary kiln, the method adjusts the primary air intake entering the rotary kiln from the kiln head according to the heat value of the materials entering the kiln and by combining a production data fitting formula, realizes the accurate control of the air intake in the rotary kiln, and further achieves the optimal proportion of the primary air intake to the secondary air intake; moreover, the invention reduces the requirements on materials entering the kiln, expands the adaptability of raw materials and reduces the energy consumption of waste disposal.

7. The method carries out cooperative treatment on the incineration residues of the rotary kiln by utilizing the sintering process of the steel plant, can effectively recover iron elements in the iron-containing solid waste, and thoroughly eliminates the environmental influence and the secondary pollution risk of the solid waste because heavy metals in the residues are treated by the sintering process. Compared with the prior art, the temperature-controlled and oxygen-controlled burning in the rotary kiln also enables the organic matters in the hazardous waste to be partially preserved and fully utilized in the sintering process, and the heat energy utilization rate is also improved. The sintering process of the invention carries out cascade utilization and layered material distribution on the residues after incineration at different temperatures, relieves the heat storage effect of the existing sinter bed, promotes uniform heat sintering and improves the sintering quality.

8. In the invention, the forward flow rotary kiln directly uses the original reverse flow rotary kiln to change the direction from air to flue gas, and the forward flow rotary kiln changes the original external heating type flue gas heat exchange pipeline into a secondary air supply pipeline, thereby realizing secondary air intake of the kiln body, changing the situation that the original combustion-supporting air enters from the kiln head, causing the kiln head to be violently combusted, the temperature to be higher, and the kiln tail air to be lower, namely the kiln body secondary air intake reduces the kiln head air intake, the kiln head temperature is reduced, the kiln tail temperature is improved, the indexing distribution of the rotary kiln is more uniform, and the reduction of nitrogen oxides is facilitated.

Drawings

FIG. 1 is a schematic structural diagram of a hazardous waste incineration rotary kiln in the prior art;

FIG. 2 is a schematic structural diagram of a counter-flow rotary kiln for treating high-volatile hazardous wastes in the present invention;

FIG. 3 isbase:Sub>A cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 5 is a schematic structural diagram of a system for co-processing hazardous wastes by a counter-flow rotary kiln-sintering machine in the invention;

FIG. 6 is a schematic structural diagram of a downstream rotary kiln for disposing low-volatile hazardous wastes in the present invention;

FIG. 7 is a schematic structural diagram of a system for co-processing hazardous wastes by using a concurrent rotary kiln and a sintering machine in the invention.

Reference numerals:

c1: a rotary kiln; 1: a kiln head; 101: a material inlet; 2: a kiln body; 201: a furnace lining; 202: a hearth; 20201: a pyrolysis chamber; 20202: an incineration chamber; 3: a kiln tail; 301: a material outlet; 302: a discharge air duct; 303: a heat supplementing burner; 304: a kiln tail air duct; 4: an air duct inside the kiln; 5: an annular air duct; 6: a primary air duct; 7: a secondary air duct; c2: sintering machine; 8: a hot slag cooler; 801: a hot slag inlet; 802: a cold slag outlet; 803: a cold medium inlet; 804: a thermal medium outlet; 9: a three-way valve; 10: an air extraction device; 11: an air volume control valve; 12: a temperature detection device; 13: a material iron content detection device; 14: a gas analyzer.

Detailed Description

The technical solution of the present invention is illustrated below, and the claimed scope of the present invention includes, but is not limited to, the following examples.

According to an embodiment of the present invention, a system for the co-disposal of hazardous waste from a rotary kiln-sintering machine is provided.

A system for rotary kiln-sintering machine cooperative disposal of hazardous waste comprises a rotary kiln C1 and a sintering machine C2 disposed downstream of the rotary kiln C1. And a kiln head 1 of the rotary kiln C1 is provided with a material inlet 101. A material outlet 301 and a discharge air duct 302 are arranged on the kiln tail 3 of the rotary kiln C1. The material outlet 301 is positioned at the bottom of the kiln tail 3. Discharge air duct 302 is located at the upper portion of material outlet 301, and discharge air duct 302 is communicated with material outlet 301. The material outlet 301 is connected to the sintering machine C2. The body 2 of the rotary kiln C1 includes a furnace lining 201 and a hearth 202. Along the material path, the furnace 202 is divided into a pyrolysis chamber 20201 and an incineration chamber 20202. An in-kiln air duct 4 is arranged inside the furnace lining 201 corresponding to the pyrolysis chamber 20201. One end of the air duct 4 in the kiln extends into the kiln head 1, and the other end is communicated with the incineration chamber 20202. The kiln head 1 is also provided with an annular air duct 5. The kiln air duct 4 is communicated with a primary air duct 6 arranged outside the rotary kiln C1 through an annular air duct 5. A plurality of secondary air ducts 7 are separated from the primary air duct 6. The secondary air ducts 7 penetrate through the kiln head 1 and are communicated with the pyrolysis chamber 20201. The plurality of secondary air ducts 7 are uniformly distributed on the kiln head 1 of the rotary kiln C1.

In the present invention, m secondary air ducts 7 are branched from the primary air duct 6. The m secondary air ducts 7 are annularly distributed around the material inlet 101. Wherein: m is 2 to 16.

In the invention, n kiln air ducts 4 are arranged in the rotary kiln C1. The n in-kiln air ducts 4 are uniformly distributed along the circumferential direction of the rotary kiln C1. Each kiln inner air duct 4 is communicated with an annular air duct 5 arranged on the kiln head 1. Wherein: n is 2 to 30.

Preferably, m is 4 to 10.

Preferably, n is 3 to 20.

Preferably, the system further includes a hot slag cooler 8 disposed between the rotary kiln C1 and the sintering machine C2. The hot slag cooler 8 is provided with a hot slag inlet 801, a cold slag outlet 802, a cold medium inlet 803 and a hot medium outlet 804. The material outlet 301 of the rotary kiln C1 is connected to the hot slag inlet 801 of the hot slag cooler 8. The cold slag outlet 802 of the hot slag cooler 8 is connected to the sintering machine C2.

In the present invention, a three-way valve 9 is disposed at a position on the primary air duct 6 from which the secondary air duct 7 branches. The secondary air duct 7 is provided with an air extractor 10 and an air volume control valve 11.

In the invention, a kiln tail 3 of the rotary kiln C1 is also provided with a heat supplementing burner 303 and a kiln tail air duct 304. The heat supplementing burner 303 and the kiln tail air duct 304 are both arranged in the middle of the kiln tail 3.

In the present invention, a temperature detection device 12 is provided in the incineration chamber 20202 of the rotary kiln C1. A material iron content detection device 13 is arranged at the material inlet 101 of the kiln head 1. A gas analyzer 14 is disposed on the primary air duct 6 near the annular air duct 5.

Example 1

As shown in fig. 2-3 and 5, a system for the cooperative disposal of hazardous waste by a rotary kiln-sintering machine includes a rotary kiln C1. The rotary kiln C1 comprises a kiln head 1, a kiln body 2 and a kiln tail 3. The kiln head 1 is provided with a material inlet 101. The kiln body 2 comprises a furnace lining 201 and a hearth 202. A material outlet 301 and a discharging air duct 302 are arranged on the kiln tail 3. The material outlet 301 is positioned at the bottom of the kiln tail 3. Discharge air duct 302 is located at the upper portion of material outlet 301, and discharge air duct 302 is communicated with material outlet 301. Along the material path, the furnace 202 is divided into a pyrolysis chamber 20201 and an incineration chamber 20202. An in-kiln air duct 4 is arranged inside the furnace lining 201 corresponding to the pyrolysis chamber 20201. One end of the air duct 4 in the kiln extends into the kiln head 1, and the other end is communicated with the incineration chamber 20202. The kiln head 1 is also provided with an annular air duct 5. The kiln air duct 4 is communicated with a primary air duct 6 arranged outside the rotary kiln C1 through an annular air duct 5. A secondary air duct 7 branches off from the primary air duct 6. The secondary air duct 7 passes through the kiln head 1 and is communicated with the pyrolysis chamber 20201. The system also includes a sintering machine C2 disposed downstream of the rotary kiln C1. The material outlet 301 is connected to a sintering machine C2.

Wherein: a plurality of secondary air ducts 7 are branched from the primary air duct 6. The plurality of secondary air ducts 7 are uniformly distributed on the kiln head 1 of the rotary kiln C1.

Example 2

Example 1 was repeated except that 4 secondary air ducts 7 were branched from the primary air duct 6. The 4 secondary air ducts 7 are annularly distributed around the material inlet 101.

Example 3

Example 2 was repeated except that 10 in-kiln air ducts 4 were provided in the rotary kiln C1. The 10 in-kiln air ducts 4 are uniformly distributed along the circumferential direction of the rotary kiln C1. Each kiln inner air duct 4 is communicated with an annular air duct 5 arranged on the kiln head 1.

Example 4

Example 1 was repeated except that 8 secondary air ducts 7 were branched from the primary air duct 6. The 8 secondary air ducts 7 are annularly distributed around the material inlet 101.

Example 5

As shown in fig. 4, example 4 was repeated except that 16 in-kiln ducts 4 were provided in the rotary kiln C1. The 16 in-kiln air ducts 4 are uniformly distributed along the circumferential direction of the rotary kiln C1. Each kiln inner air duct 4 is communicated with an annular air duct 5 arranged on the kiln head 1.

Example 6

Example 5 was repeated except that the system further included a hot slag cooler 8 disposed between the rotary kiln C1 and the sintering machine C2. The hot slag cooler 8 is provided with a hot slag inlet 801, a cold slag outlet 802, a cold medium inlet 803 and a hot medium outlet 804. The material outlet 301 of the rotary kiln C1 is connected to the hot slag inlet 801 of the hot slag cooler 8. The cold slag outlet 802 of the hot slag cooler 8 is connected to the sintering machine C2.

Example 7

Example 6 is repeated except that a three-way valve 9 is provided at a position on the primary air duct 6 from which the secondary air duct 7 is branched. The secondary air duct 7 is provided with an air extractor 10 and an air volume control valve 11.

Example 8

Example 7 is repeated, except that the kiln tail 3 of the rotary kiln C1 is further provided with a concurrent heating burner 303 and a kiln tail air duct 304. The heat supplementing burner 303 and the kiln tail air duct 304 are both arranged in the middle of the kiln tail 3.

Example 9

Example 8 is repeated except that a temperature detecting device 12 is provided in the incineration chamber 20202 of the rotary kiln C1. A material iron content detection device 13 is arranged at the material inlet 101 of the kiln head 1. A gas analyzer 14 is arranged on the primary air duct 6 and close to the annular air duct 5.

Example 10

A method of rotary kiln-sinter machine co-disposing hazardous waste using the system described in example 9, comprising the steps of:

1) Pyrolysis: the high volatile matter hazardous waste is conveyed into the rotary kiln C1 through the material inlet 101 of the kiln head 1. Combustion air enters the rotary kiln C1 through a discharge duct 302 of the kiln tail 3 and a kiln tail duct 304. The high volatile content hazardous waste first enters the pyrolysis chamber 20201 of the rotary kiln C1 for drying and pyrolysis. The material residue and pyrolysis gas after pyrolysis enter the incineration chamber 20202.

2) And (3) incineration: the material residues, pyrolysis gas and combustion air are mixed and combusted in the incineration chamber 20202. The burned hot slag is discharged out of the rotary kiln C1 through a material outlet 301 of the kiln tail 3. The burned flue gas is discharged out of the rotary kiln C1 through an air duct 4 in the kiln, an annular air duct 5 and a primary air duct 6.

3) Flue gas circulation: and (3) part of the flue gas entering the primary air channel 6 in the step 2) enters the rotary kiln C1 again through a plurality of secondary air channels 7 uniformly distributed on the kiln head 1, and the pyrolysis and incineration processes are completed together with the materials in the rotary kiln C1.

4) And (3) cooling: in the process of discharging the hot slag from the rotary kiln C1 in the step 2), the combustion air entering the discharge air duct 302 first cools the hot slag once. Meanwhile, heated combustion air enters the rotary kiln C1 to participate in pyrolysis and incineration of materials. And the hot slag after primary cooling enters the hot slag cooler 8, and exchanges heat with a cooling medium introduced into the hot slag cooler 8 to obtain cold slag and a hot medium after heat exchange is finished.

Wherein: in the step 3), a gas analyzer 14 arranged on the primary air channel 6 detects the combustible content in the burned flue gas, and records the combustible content as C _g % of the amount of the compound (b). Simultaneously obtaining the temperature T of the burned flue gas _g And K. And calculating the proportion Z and percent of the flow of the circulating flue gas entering the rotary kiln C1 through the secondary air duct 7 to the total flow of the burned flue gas. Namely, the following steps are included:

the proportion of the flow of the circulating flue gas which enters the rotary kiln C1 again through the secondary air duct 7 to the total flow of the flue gas after incineration is controlled to be Z by the air extractor 10 and the air volume control valve 11.

Example 11

Example 10 is repeated, except that in step 4) the cooling medium introduced into the hot slag cooler 8 is cold air. The cold air is discharged from the heat medium outlet 804 after being heat-exchanged into hot air in the hot slag cooler 8, and the hot air is delivered to the kiln tail air duct 304 of the rotary kiln C1 as combustion-supporting air.

Example 12

Example 10 is repeated, except that in step 4), the cooling medium introduced into the hot slag cooler 8 is cooling water. The cooling water is converted into hot water by heat exchange in the hot slag cooler 8, and is discharged from the heat medium outlet 804, and the hot water is used as boiler feed water.

Example 13

Example 11 is repeated except that in step 2), the iron content w,%, of the high volatile matter hazardous waste entering the rotary kiln C1 is detected by the material iron content detection device 13. Controlling the combustion temperature T in the incineration chamber 20202 depending on the detected iron content of the material ₀ At deg.C. The method specifically comprises the following steps:

when w is more than 50%, T ₀ Is 550-650 ℃.

When w is more than 25% and less than or equal to 50%, T ₀ Is 650-750 ℃.

When w is less than 5%, T ₀ Is 850-950 ℃.

Example 14

A method for disposing hazardous waste in a rotary kiln-sintering machine cooperation manner, using the system described in embodiment 9, wherein the rotary kiln C1 is shown in fig. 6, and the overall system structure of the rotary kiln-sintering machine is shown in fig. 7, the method comprising the following steps:

a) The low-volatile matter hazardous waste is conveyed into the rotary kiln C1 through the material inlet 101 of the kiln head 1. Combustion air enters the rotary kiln C1 through a plurality of secondary air ducts 7 uniformly distributed in the kiln head 1. Meanwhile, combustion-supporting air also enters the incineration chamber 20202 of the rotary kiln C1 through the primary air duct 6, the annular air duct 5 and the in-kiln air duct 4. The low volatile hazardous waste mixes with the combustion air and is combusted in the furnace 202.

b) The burned hot slag is discharged out of the rotary kiln C1 through a material outlet 301 of the kiln tail 3. The burned flue gas is discharged out of the rotary kiln C1 through the discharge air duct 302 and the kiln tail air duct 304.

c) Conveying the hot slag discharged from the rotary kiln C1 in the step b) to a hot slag cooler 8, and introducing a cooling medium into the hot slag cooler 8. The hot slag and the cooling medium exchange heat in the hot slag cooler 8, and cold slag and the heating medium are obtained after the heat exchange is finished.

Wherein: only in step a), calculating the proportion L and percent of the air quantity entering the rotary kiln C1 from the kiln head 1 to the total air quantity required by the rotary kiln C1 through the secondary air duct 7 according to the heat value Q and kcal/kg of the low-volatile hazardous waste material conveyed to the rotary kiln C1. Namely, the following steps are included:

the proportion of the air quantity entering the rotary kiln C1 from the kiln head 1 through the secondary air duct 7 to the total air quantity required by the rotary kiln C1 is controlled to be L through the air extracting device 10 and the air quantity control valve 11.

Application example 1

The method of example 13 is used to dispose of high volatile hazardous waste, comprising the steps of:

1) Pyrolysis: the high volatile matter hazardous waste is conveyed into the rotary kiln C1 through the material inlet 101 of the kiln head 1. Combustion air enters the rotary kiln C1 through the discharge air duct 302 and the kiln tail air duct 304 of the kiln tail 3. The high volatile content hazardous waste first enters the pyrolysis chamber 20201 of the rotary kiln C1 for drying and pyrolysis. The material residue and pyrolysis gas after pyrolysis enter the incineration chamber 20202.

2) And (3) incineration: the material residues, the pyrolysis gas and the combustion air are mixed and combusted in the incineration chamber 20202. The burned hot slag is discharged out of the rotary kiln C1 through a material outlet 301 of the kiln tail 3. The burned flue gas is discharged out of the rotary kiln C1 through the in-kiln air duct 4, the annular air duct 5 and the primary air duct 6.

3) Flue gas circulation: and in the step 2), part of the flue gas entering the primary air channel 6 enters the rotary kiln C1 again through a plurality of secondary air channels 7 uniformly distributed on the kiln head 1, and pyrolysis and incineration processes are completed together with the materials in the rotary kiln C1.

4) And (3) cooling: in the process of discharging the hot slag in the step 2) out of the rotary kiln C1, the combustion air entering the discharge duct 302 first cools the hot slag once. Meanwhile, heated combustion air enters the rotary kiln C1 to participate in pyrolysis and incineration of materials. And the hot slag after primary cooling enters the hot slag cooler 8, and exchanges heat with a cooling medium introduced into the hot slag cooler 8 to obtain cold slag and a hot medium after heat exchange is finished.

Wherein, in the step 2), the iron content w =26% of the high volatile matter hazardous waste entering the rotary kiln C1 is detected by the material iron content detection device 13. Controlling the combustion temperature T in the incineration chamber 20202 depending on the detected iron content of the material ₀ ＝747℃。

In the step 3), a gas analyzer 14 arranged on the primary air channel 6 detects the combustible content in the burned flue gas, and records the combustible content as C _g =30%. Simultaneously obtaining the temperature T of the burned flue gas _g =689K. And calculating the proportion Z of the flow of the circulating flue gas entering the rotary kiln C1 through the secondary air duct 7 to the total flow of the burned flue gas. Namely, the method comprises the following steps:

the proportion of the flow of the circulating flue gas which enters the rotary kiln C1 again through the secondary air duct 7 to the total flow of the flue gas after incineration is controlled by the air extractor 10 and the air volume control valve 11 to be 42.3 percent.

Application example 2

Example 1 was repeated except that in step 2), the iron content of the material was measured by the measuring device 13And measuring the iron content w =4% of the high-volatile dangerous waste entering the rotary kiln C1. Controlling the combustion temperature T in the incineration chamber 20202 depending on the detected iron content of the material ₀ ＝875℃。

In the step 3), a gas analyzer 14 arranged on the primary air channel 6 detects the combustible content in the burned flue gas, and records the combustible content as C _g =10%. Simultaneously obtaining the temperature T of the burned flue gas _g =425K. And calculating the proportion Z of the flow of the circulating flue gas entering the rotary kiln C1 through the secondary air duct 7 to the total flow of the burned flue gas. Namely, the following steps are included:

the proportion of the flow of the circulating flue gas which enters the rotary kiln C1 again through the secondary air duct 7 to the total flow of the flue gas after incineration is controlled to be 10.1% by the air extractor 10 and the air volume control valve 11.

Application example 3

Example 1 was repeated except that in step 2), the high volatile content hazardous waste w =56% entering the rotary kiln C1 was detected by the material iron content detection device 13. Controlling the combustion temperature T in the incineration chamber 20202 depending on the detected iron content of the material ₀ ＝612℃。

In the step 3), a gas analyzer 14 arranged on the primary air duct 6 detects the combustible content in the burned flue gas, and the content is marked as C _g =20%. Simultaneously obtaining the temperature T of the burned flue gas _g =523K. And calculating the proportion Z of the flow of the circulating flue gas entering the rotary kiln C1 through the secondary air duct 7 to the total flow of the burned flue gas. Namely, the method comprises the following steps:

the proportion of the flow of the circulating flue gas which enters the rotary kiln C1 again through the secondary air duct 7 to the total flow of the flue gas after incineration is controlled to be 24.7 percent by the air extractor 10 and the air volume control valve 11.

Application example 4

The method of example 14 for disposing of low volatile hazardous waste, comprising the steps of:

a) The low volatile matter hazardous waste is conveyed into the rotary kiln C1 through the material inlet 101 of the kiln head 1. Combustion air enters the rotary kiln C1 through a plurality of secondary air ducts 7 uniformly distributed in the kiln head 1. Meanwhile, combustion-supporting air also enters the incineration chamber 20202 of the rotary kiln C1 through the primary air duct 6, the annular air duct 5 and the kiln air duct 4. The low volatile hazardous waste is mixed with combustion air in the furnace 202 and combusted.

In the step a), the calorific value Q =1200kcal/kg of the low-volatile matter hazardous waste material conveyed to the rotary kiln C1 is obtained, and the proportion L of the air volume entering the rotary kiln C1 from the kiln head 1 through the secondary air duct 7 to the total air volume required by the rotary kiln C1 is calculated. Namely, the method comprises the following steps:

the air quantity entering the rotary kiln C1 from the kiln head 1 through the secondary air duct 7 is controlled by the air extraction device 10 and the air quantity control valve 11 to account for 21% of the total air quantity required by the rotary kiln C1, and at the moment, the air quantity entering the rotary kiln C1 from the kiln body 2 through the primary air duct 6, the annular air duct 5 and the in-kiln air duct 4 accounts for 79% of the total air quantity required by the rotary kiln C1.

Application example 5

The example 4 is repeatedly applied, except that in the step a), the calorific value Q =1600kcal/kg of the low-volatile matter hazardous waste material conveyed to the rotary kiln C1 is obtained, and the proportion L of the air quantity entering the rotary kiln C1 from the kiln head 1 through the secondary air duct 7 to the total air quantity required by the rotary kiln C1 is calculated. Namely, the method comprises the following steps:

the air quantity entering the rotary kiln C1 from the kiln head 1 through the secondary air duct 7 is controlled by the air extraction device 10 and the air quantity control valve 11 to account for 9% of the total air quantity required by the rotary kiln C1, and at the moment, the air quantity entering the rotary kiln C1 from the kiln body 2 through the primary air duct 6, the annular air duct 5 and the in-kiln air duct 4 accounts for 91% of the total air quantity required by the rotary kiln C1.

Claims

1. A method for rotary kiln-sintering machine cooperative disposal of hazardous waste, the method comprising the steps of:

1) Pyrolysis: conveying the high-volatile hazardous waste into a rotary kiln (C1) through a material inlet (101) of the kiln head (1); combustion-supporting air enters the rotary kiln (C1) through a discharge air duct (302) and a kiln tail air duct (304) of the kiln tail (3); high-volatile hazardous waste firstly enters a pyrolysis chamber (20201) of the rotary kiln (C1) for drying and pyrolysis; the material residue and pyrolysis gas after pyrolysis enter an incineration chamber (20202);

2) And (3) incineration: the material residues, the pyrolysis gas and the combustion-supporting air are mixed in the incineration chamber (20202) and are combusted; the burned hot slag is discharged out of the rotary kiln (C1) through a material outlet (301) of the kiln tail (3); the burned flue gas is discharged out of the rotary kiln (C1) through an air duct (4) in the kiln, an annular air duct (5) and a primary air duct (6);

3) Flue gas circulation: part of the flue gas entering the primary air channel (6) in the step 2) enters the rotary kiln (C1) again through a plurality of secondary air channels (7) uniformly distributed on the kiln head (1) and completes pyrolysis and incineration procedures together with the materials in the rotary kiln (C1);

4) And (3) cooling: in the process of discharging the hot slag out of the rotary kiln (C1) in the step 2), firstly, carrying out primary cooling on the hot slag by combustion-supporting air entering a discharge air duct (302); meanwhile, heated combustion-supporting air enters the rotary kiln (C1) to participate in pyrolysis and incineration of materials; the hot slag after primary cooling enters a hot slag cooler (8) and exchanges heat with a cooling medium introduced into the hot slag cooler (8) to obtain cold slag and a hot medium after heat exchange is finished;

5) And (3) sintering: distributing the cold slag and the sintering raw material obtained in the step 4) on a sintering trolley, and igniting and sintering;

wherein: in the step 3), a gas analyzer (14) arranged on the primary air channel (6) detects the combustible content in the burned smoke and records the combustible content as C _g And (c); simultaneously obtains the temperature T of the burned flue gas _g K; calculating the proportion Z and percent of the flow of the circulating flue gas entering the rotary kiln (C1) through the secondary air duct (7) to the total flow of the burned flue gas; namely, the method comprises the following steps:

the proportion of the flow of the circulating flue gas which enters the rotary kiln (C1) again through the secondary air duct (7) to the total flow of the burned flue gas is controlled to be Z by an air extractor (10) and an air flow control valve (11);

wherein: the high-volatile matter hazardous waste is hazardous waste with the mass percentage content of dry-based volatile matter being more than or equal to H%, and H is 6-12.

2. The method of claim 1, wherein: h is 7-10.

3. The method according to claim 1 or 2, characterized in that: in the step 2), detecting the iron content w,%, of the high volatile matter hazardous waste entering the rotary kiln (C1) by a material iron content detection device (13); controlling the combustion temperature T in the incineration chamber (20202) depending on the detected iron content of the material ₀ DEG C; the method specifically comprises the following steps:

when w is more than 50%, T ₀ Is 550-650 ℃;

when w is more than 25% and less than or equal to 50%, T ₀ Is 650 to 750 ℃;

when w is more than or equal to 5% and less than or equal to 25%, T ₀ Is 750 to 850 ℃;

when w is less than 5%, T ₀ Is 850-950 ℃.

4. A method for co-disposing hazardous wastes with a rotary kiln-sintering machine, comprising the steps of:

a) Conveying the low-volatile hazardous waste into a rotary kiln (C1) through a material inlet (101) of the kiln head (1); combustion-supporting air enters the rotary kiln (C1) through a plurality of secondary air channels (7) uniformly distributed on the kiln head (1); meanwhile, combustion-supporting air enters an incineration chamber (20202) of the rotary kiln (C1) through a primary air duct (6), an annular air duct (5) and an in-kiln air duct (4); the low-volatile hazardous waste and combustion-supporting air are mixed in the hearth (202) and are combusted;

b) Discharging the burned hot slag out of the rotary kiln (C1) through a material outlet (301) of the kiln tail (3); the burned flue gas is discharged out of the rotary kiln (C1) through a discharge air duct (302) and a kiln tail air duct (304);

c) Conveying the hot slag discharged from the rotary kiln (C1) in the step b) to a hot slag cooler (8), and introducing a cooling medium into the hot slag cooler (8); carrying out heat exchange between the hot slag and the cooling medium in a hot slag cooler (8), and obtaining cold slag and the heating medium after the heat exchange is finished;

d) Distributing the cold slag and the sintering raw material obtained in the step c) on a sintering trolley, and igniting and sintering;

wherein: in the step a), calculating the proportion L and percent of the air quantity entering the rotary kiln (C1) from the kiln head (1) to the total air quantity required by the rotary kiln (C1) through the secondary air duct (7) according to the heat value Q, kcal/kg of the low-volatile hazardous waste material conveyed to the rotary kiln (C1); namely, the method comprises the following steps:

the proportion of the air quantity entering the rotary kiln (C1) from the kiln head (1) through the secondary air duct (7) to the total air quantity required by the rotary kiln (C1) is controlled to be L through an air extracting device (10) and an air quantity control valve (11);

the low-volatile component hazardous waste is hazardous waste with the mass percentage content of dry-basis volatile components less than H%, and H is 6-12.

5. The method of claim 4, wherein: h is 7-10.

6. System for the rotary kiln-sinter co-disposal of hazardous waste for the method according to any one of claims 1 to 5, comprising a rotary kiln (C1) and a sinter (C2) arranged downstream of the rotary kiln (C1); a material inlet (101) is formed in the kiln head (1) of the rotary kiln (C1); a material outlet (301) and a discharge air duct (302) are arranged on the kiln tail (3) of the rotary kiln (C1); the material outlet (301) is positioned at the bottom of the kiln tail (3); the discharging air channel (302) is positioned at the upper part of the material outlet (301), and the discharging air channel (302) is communicated with the material outlet (301); the material outlet (301) is connected to a sintering machine (C2); the kiln body (2) of the rotary kiln (C1) comprises a furnace lining (201) and a hearth (202); along the material direction, the hearth (202) is divided into a pyrolysis chamber (20201) and an incineration chamber (20202); an air duct (4) in the kiln is arranged in the furnace lining (201) corresponding to the pyrolysis chamber (20201); one end of an air duct (4) in the kiln extends into the kiln head (1), and the other end is communicated with the incineration chamber (20202); the kiln head (1) is also provided with an annular air duct (5); the kiln air duct (4) is communicated with a primary air duct (6) arranged outside the rotary kiln (C1) through an annular air duct (5); a plurality of secondary air ducts (7) are separated from the primary air duct (6); the secondary air ducts (7) penetrate through the kiln head (1) and are communicated with the pyrolysis chamber (20201); the secondary air ducts (7) are uniformly distributed on the kiln head (1) of the rotary kiln (C1).

7. The system of claim 6, wherein: m secondary air ducts (7) are separated from the primary air duct (6); the m secondary air ducts (7) are annularly distributed around the material inlet (101); wherein: m is 2 to 16; and/or

N kiln air ducts (4) are arranged in the rotary kiln (C1); the n kiln air ducts (4) are uniformly distributed along the circumferential direction of the rotary kiln (C1); each kiln inner air duct (4) is communicated with an annular air duct (5) arranged on the kiln head (1); wherein: n is 2 to 30.

8. The system of claim 7, wherein: m is 4 to 10; and/or

n is 3 to 20.

9. The system of claim 6, wherein: the system also comprises a hot slag cooler (8) arranged between the rotary kiln (C1) and the sintering machine (C2); the hot slag cooler (8) is provided with a hot slag inlet (801), a cold slag outlet (802), a cold medium inlet (803) and a hot medium outlet (804); the material outlet (301) of the rotary kiln (C1) is connected to the hot slag inlet (801) of the hot slag cooler (8); the cold slag outlet (802) of the hot slag cooler (8) is connected to the sintering machine (C2).

10. The system according to any one of claims 6-9, wherein: a three-way valve (9) is arranged at the position of the primary air duct (6) where the secondary air duct (7) is divided; an air extractor (10) and an air control valve (11) are arranged on the secondary air duct (7).

11. The system of claim 10, wherein: a heat supplementing burner (303) and a kiln tail air duct (304) are also arranged on the kiln tail (3) of the rotary kiln (C1); the concurrent heating burner (303) and the kiln tail air duct (304) are both arranged in the middle of the kiln tail (3).

12. The system of claim 11, wherein: a temperature detection device (12) is arranged in an incineration chamber (20202) of the rotary kiln (C1); a material iron content detection device (13) is arranged at a material inlet (101) of the kiln head (1); and a gas analyzer (14) is arranged on the primary air duct (6) and close to the annular air duct (5).