阅读说明：本技术 一种利用燃煤锅炉掺烧危废的节能型系统及方法 (Energy-saving system and method for utilizing coal-fired boiler to mix and burn hazardous waste ) 是由 孙宁 贺帅 佘艳 马国保 黄河 周志江 王兴琦 于 2021-09-14 设计创作，主要内容包括：本发明公开了一种利用燃煤锅炉掺烧危废的节能型系统及方法,系统包括煤粉进料单元、危废进料单元、送风单元及燃煤锅炉；煤粉进料单元包括封闭式煤粉仓；危废进料单元包括依次连接的封闭式危废料坑、干燥装置、破碎装置及粉碎装置,粉碎装置与燃煤锅炉连接；送风单元包括空气预热器以及分别与空气预热器连接的一次风机和二次风机；一次风机和二次风机分别通过一次送风管路和二次送风管路依次与空气预热器和燃煤锅炉连接；封闭式煤粉仓与空气预热器及燃煤锅炉之间的一次送风管路连接；干燥装置与空气预热器及燃煤锅炉之间的二次送风管路连接。本发明利用二次风中的热量对危废进行干燥,减少了烘干所需额外热源的使用,降低了系统的能源消耗。(The invention discloses an energy-saving system and method for co-burning hazardous waste by using a coal-fired boiler, wherein the system comprises a pulverized coal feeding unit, a hazardous waste feeding unit, an air supply unit and the coal-fired boiler; the coal powder feeding unit comprises a closed coal powder bin; the hazardous waste feeding unit comprises a closed hazardous waste pit, a drying device, a crushing device and a crushing device which are connected in sequence, and the crushing device is connected with the coal-fired boiler; the air supply unit comprises an air preheater, and a primary fan and a secondary fan which are respectively connected with the air preheater; the primary air blower and the secondary air blower are respectively connected with the air preheater and the coal-fired boiler in sequence through a primary air supply pipeline and a secondary air supply pipeline; the closed pulverized coal bin is connected with a primary air supply pipeline between the air preheater and the coal-fired boiler; the drying device is connected with a secondary air supply pipeline between the air preheater and the coal-fired boiler. The invention utilizes the heat in the secondary air to dry the hazardous waste, reduces the use of an extra heat source required by drying and reduces the energy consumption of the system.)

1. An energy-saving system for co-combustion of hazardous waste by using a coal-fired boiler is characterized by comprising a pulverized coal feeding unit, a hazardous waste feeding unit, an air supply unit and the coal-fired boiler (11);

the coal powder feeding unit comprises a closed coal powder bin (10); the hazardous waste feeding unit comprises a closed hazardous waste pit (1), a drying device (2), a crushing device (3) and a crushing device (4) which are connected in sequence, and the crushing device is connected with the coal-fired boiler; the air supply unit comprises an air preheater (7), and a primary fan (5) and a secondary fan (6) which are respectively connected with the air preheater;

the primary air fan and the secondary air fan are respectively connected with the air preheater and the coal-fired boiler in sequence through a primary air supply pipeline (8) and a secondary air supply pipeline (9); the closed pulverized coal bin is connected with a primary air supply pipeline between the air preheater and the coal-fired boiler; and the drying device is connected with a secondary air supply pipeline between the air preheater and the coal-fired boiler.

2. The energy-saving system for co-burning hazardous waste by using the coal-fired boiler as claimed in claim 1, wherein the secondary air supply pipeline between the air preheater and the coal-fired boiler comprises a first branch (901) and a second branch (902), the first branch is directly connected with the air preheater and the coal-fired boiler, and the second branch is sequentially connected with the air preheater, the drying device and the coal-fired boiler.

3. The energy-saving system for co-combustion of hazardous waste by using a coal-fired boiler according to claim 1, wherein the pulverized coal feeding unit further comprises a first feeding device (12) respectively connected with the closed pulverized coal bunker and the primary air supply pipeline.

4. The energy-saving system for co-burning hazardous wastes in the coal-fired boiler according to claim 3, wherein a mixer (13) is arranged on a primary air supply pipeline between the air preheater and the coal-fired boiler, and the mixer is connected with the first feeding device.

5. The energy-saving system for blending hazardous wastes with a coal-fired boiler according to claim 1, wherein the hazardous waste feeding unit further comprises a second feeding device (14) respectively connected with the crushing device and the coal-fired boiler.

6. The energy-saving system for blending and burning hazardous waste by using a coal-fired boiler as claimed in claim 1, wherein the crushing device and the crushing device are respectively provided with a gas-collecting hood (15), and the gas-collecting hood, the closed pulverized coal bunker and the closed hazardous waste pit are connected with the coal-fired boiler through a gas-collecting pipeline (16).

7. A method for blending hazardous waste with the system according to any one of claims 1 to 6, which is characterized by comprising the following steps:

(1) mixing the oily sludge and the vinasse in a closed hazardous waste pit, feeding the mixture into a drying device, and drying the mixture by secondary air provided by a secondary fan;

(2) crushing and crushing the dried mixture to obtain dangerous waste powder;

(3) and sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration.

8. The method for co-firing hazardous waste according to claim 7, wherein the mass ratio of the oily sludge to the vinasse in the step (1) is 35-40: 15, wherein the water content of the oily sludge is 30-35%, and the water content of the vinasse is 60-70%.

9. The method for co-burning hazardous waste according to claim 7 or 8, wherein the mass ratio of the hazardous waste powder to the pulverized coal is 20: 80-30: 70.

10. The method for blending burning hazardous waste according to claim 7, wherein the temperature of the secondary air is 200-250 ℃.

Technical Field

The invention relates to the technical field of hazardous waste treatment, in particular to an energy-saving system and method for co-burning hazardous waste by using a coal-fired boiler.

Background

Hazardous waste refers to waste having various toxic, flammable, explosive, corrosive, chemical reactivity and infectivity characteristics, as set forth in the national hazardous waste list or recognized according to the national hazardous waste identification standards and methods. Hazardous waste is of a wide variety and complex composition, with potential and delayed contamination. With the continuous and rapid development of economy in China, the living standard of people is continuously improved, the requirements of people on safety and environmental protection are more urgent than ever before, and the safe treatment and disposal of hazardous wastes are the only way for eliminating the harmfulness of the hazardous wastes.

The hazardous waste is mixed into the fire coal to be used as fuel, so that the volume reduction, weight reduction and resource utilization of the hazardous waste can be realized, the fire coal cost is reduced, and the method is an economical and feasible hazardous waste treatment method. When the hazardous waste and the coal are mixed and burnt, because the hazardous waste materials are generally complex in dry and wet shapes, the hazardous waste materials need to be dried before burning and then burnt after being crushed. For example, the patent document of china discloses "a system and a method for blending solid hazardous waste and reducing dioxin discharge in a chain grate furnace", which is published under the publication number CN111457388A, and the system comprises a chain grate, a pyrolysis reactor, a dryer, a water spray desuperheater, an ash collector, a tail flue and a chimney.

In the prior art, when the hazardous waste and the coal are co-burned, the hazardous waste is generally dried by using an external energy source, so that the consumption of the energy source for co-burning the hazardous waste by using the coal-fired boiler is high, and the economic and social benefits of hazardous waste disposal are reduced.

Disclosure of Invention

The invention provides an energy-saving system and method for co-burning hazardous waste by using a coal-fired boiler, aiming at overcoming the problem that the energy consumption is large in the treatment process because the hazardous waste needs to be dried by using an external energy source firstly and then crushed and burned when the coal-fired boiler is used for co-burning the hazardous waste in the prior art, and the heat in secondary air is used for drying the hazardous waste, so that the use of an additional heat source required by drying is reduced, and the energy consumption of the system is reduced.

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

an energy-saving system for co-combustion of hazardous waste by using a coal-fired boiler comprises a pulverized coal feeding unit, a hazardous waste feeding unit, an air supply unit and the coal-fired boiler; the coal powder feeding unit comprises a closed coal powder bin; the hazardous waste feeding unit comprises a closed hazardous waste pit, a drying device, a crushing device and a crushing device which are connected in sequence, and the crushing device is connected with the coal-fired boiler; the air supply unit comprises an air preheater, and a primary fan and a secondary fan which are respectively connected with the air preheater; the primary air fan and the secondary air fan are respectively connected with the air preheater and the coal-fired boiler in sequence through a primary air supply pipeline and a secondary air supply pipeline; the closed pulverized coal bin is connected with a primary air supply pipeline between the air preheater and the coal-fired boiler; and the drying device is connected with a secondary air supply pipeline between the air preheater and the coal-fired boiler.

The invention arranges a primary fan and a secondary fan in an air supply unit, wherein primary air provided by the primary fan is heated by an air preheater and then is used for conveying coal dust in a closed coal dust bin into a coal-fired boiler through a primary air supply pipeline; the secondary air provided by the secondary fan is heated by the air preheater and then enters the coal-fired boiler for supplementing oxygen for the combustion of the pulverized coal and the hazardous waste, enhancing the disturbance of air flow, promoting the backflow of high-temperature flue gas, promoting the mixing of the pulverized coal, the hazardous waste and the oxygen, improving the combustion efficiency and providing conditions for complete combustion. Meanwhile, the drying device in the hazardous waste feeding unit is connected with the secondary air supply pipeline, the hazardous waste is dried by using the heat in the secondary air, and then the secondary air enters the coal-fired boiler; the secondary air has higher temperature and higher air speed, can quickly bring out higher-content water in the target hazardous waste, reduces the use of an additional heat source required by drying the hazardous waste and reduces the energy consumption of a system; volatile organic compounds and moisture generated in the drying process enter the coal-fired boiler again along with the air supply unit through the secondary air supply pipeline to be incinerated, so that secondary pollution is avoided. The dried hazardous waste is crushed into powder by the crushing device and then enters the coal-fired boiler to be co-fired with the pulverized coal, so that the volume reduction, weight reduction and resource recycling of the hazardous waste are realized.

Preferably, the secondary air supply pipeline between the air preheater and the coal-fired boiler comprises a first branch and a second branch, the first branch is directly connected with the air preheater and the coal-fired boiler, and the second branch is sequentially connected with the air preheater, the drying device and the coal-fired boiler. According to the invention, the two branches are arranged on the secondary air supply pipeline, so that the secondary air heated by the air preheater is divided into two paths, one path directly enters the coal-fired boiler to provide oxygen for combustion, and the other path firstly passes through the drying device to dry hazardous waste and then enters the coal-fired boiler, thereby being beneficial to ensuring that the temperature of the secondary air entering the boiler can meet the combustion requirement.

Preferably, the ratio of the air supply amount of the first fan to the air supply amount of the second fan is 50:50 to 60: 40. By adopting the air distribution mode, the coal-fired boiler has good combustion stability and combustion efficiency, and slag bonding is reduced.

Preferably, the pulverized coal feeding unit further comprises a first feeding device respectively connected with the closed pulverized coal bin and the primary air supply pipeline.

Preferably, a mixer is arranged on a primary air supply pipeline between the air preheater and the coal-fired boiler, and the mixer is connected with the first feeding device.

According to the invention, the feeding device and the mixer are arranged in the coal powder feeding unit, so that the primary air and the coal powder can be uniformly mixed, and the combustion stability of the coal-fired boiler can be improved. When the coal powder mixer works, coal powder in the closed coal powder bin enters the mixer through the first feeding device, is mixed with primary air which is output by the primary fan and heated by the air preheater in the mixer, and is conveyed into the coal-fired boiler by the primary air.

Preferably, the hazardous waste feeding unit further comprises a second feeding device which is respectively connected with the crushing device and the coal-fired boiler.

Preferably, the crushing device and the crushing device are respectively provided with a gas collecting hood, and the gas collecting hood, the closed pulverized coal bunker and the closed hazardous waste pit are connected with the coal-fired boiler through a gas collecting pipeline. The gas collecting hood is arranged on the crushing device and the crushing device to seal the crushing device and the crushing device, so that the whole process is carried out under a totally closed condition, and the gas in the closed coal dust bin and the closed hazardous waste pit and the gas collected by the gas collecting hood are collected together through the gas collecting pipeline and sent into the coal-fired boiler to be combusted, so that the pollution of volatile organic compounds to the environment and the operation space in the treatment process is avoided.

The invention also provides a method for blending burning hazardous wastes by using the system, which comprises the following steps:

(1) mixing the oily sludge and the vinasse in a closed hazardous waste pit, feeding the mixture into a drying device, and drying the mixture by secondary air provided by a secondary fan;

(2) crushing and crushing the dried mixture to obtain dangerous waste powder;

(3) and sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration.

The oily sludge belongs to HW08 waste in national hazardous waste records, contains a large amount of aged crude oil, wax, asphaltene, benzene series, phenols, anthracene, heavy metal and other substances, and is easy to cause secondary pollution if not treated properly; the invention mixes the oily sludge into the coal dust for incineration, and can achieve the aim of harmless treatment of the oily sludge. However, because the oily sludge contains a large amount of N, S, P, C, O, heavy metals and other elements, a large amount of harmful flue gas can be generated in the combustion process, and NO in the flue gas is increased when coal is fired_X、SO₂And heavy metal discharge amount, not meeting the standard requirement; therefore, it isIn order to control the emission of flue gas, the invention also mixes vinasse and oily sludge together with coal powder for mixed combustion. The incorporation of distiller's grains can exert sulfur fixing effect, and can improve CO and H₂、CH₄The amount of reducing gas generated is equal to the amount of NO generated_XReduction of (3) to reduce SO₂And NO_XDischarging; meanwhile, the vinasse is rich in various mineral components capable of trapping heavy metals, so that a chemical adsorption site can be provided for the heavy metals, volatilization of the heavy metals and leaching concentration of the heavy metals are reduced, and enrichment and stabilization of the heavy metals in ash can be realized. Therefore, the invention realizes the harmless and resource treatment of the oil-containing sludge and the vinasse by mixing and burning the oil-containing sludge, the vinasse and the coal powder, changes the current situation that the coal-fired boiler singly treats hazardous waste, improves the utilization rate of the coal-fired boiler and obtains more economic benefits.

Preferably, the mass ratio of the oily sludge to the vinasse in the step (1) is 35-40: 15, wherein the water content of the oily sludge is 30-35%, and the water content of the vinasse is 60-70%.

Preferably, the mass ratio of the hazardous waste powder to the pulverized coal is 20: 80-30: 70.

Because the water content of the vinasse is high, the vinasse is not easy to dry, if the adding amount of the vinasse is too much, the water content of the dried hazardous waste powder is high, and the combustion efficiency is reduced; and the addition of too little vinasse can cause NO in smoke_X、SO₂And the discharge amount of heavy metals cannot be effectively controlled; and the addition of the vinasse and the oily sludge can reduce the melting point of ash, so that the slag is easy to form in the combustion process; therefore, the mixing amount of the oil-containing sludge and the vinasse has great influence on the combustion condition and the discharge of pollutants, and the invention controls the mixing ratio of the oil-containing sludge, the vinasse and the coal powder to ensure that the oil-containing sludge and the vinasse can be effectively dried under the action of secondary air, improve the combustion efficiency and simultaneously reduce NO in the combustion process_X、SO₂And the discharge of heavy metal reduces the slag bonding phenomenon.

Preferably, the temperature of the secondary air is 200-250 ℃. The temperature of the secondary air is in the range, so that the temperature of the secondary air entering the boiler after drying can meet the combustion requirement, and meanwhile, the moisture in the oily sludge and the vinasse can be effectively brought out, and the hazardous waste is dried.

Therefore, the invention has the following beneficial effects:

(1) the oily sludge, the vinasse and the coal powder are mixed and burnt, so that the harmless and resource treatment of the oily sludge and the vinasse is realized, the current situation that the coal-fired boiler singly treats hazardous waste is changed, the utilization rate of the coal-fired boiler is improved, and more economic benefits are obtained;

(2) the drying device in the hazardous waste feeding unit is connected with the secondary air supply pipeline, the hazardous waste is dried by using the heat in the secondary air, and then the secondary air enters the coal-fired boiler, so that the use of an additional heat source required by hazardous waste drying is reduced, and the energy consumption of a system is reduced;

(3) the whole process is carried out under the totally closed condition, volatile organic compounds volatilized by all devices are collected by the gas collecting pipeline and are sent into the coal-fired boiler together for combustion, and the pollution of the volatile substances to the environment and the operation space is avoided.

Drawings

Fig. 1 is a schematic view of a connection structure of the present invention.

In the figure: the device comprises a closed hazardous waste pit 1, a drying device 2, a crushing device 3, a crushing device 4, a primary fan 5, a secondary fan 6, an air preheater 7, a primary air supply pipeline 8, a secondary air supply pipeline 9, a first branch 901, a second branch 902, a closed coal dust bin 10, a coal-fired boiler 11, a first feeding device 12, a mixer 13, a second feeding device 14, a gas collecting hood 15 and a gas collecting pipeline 16.

Detailed Description

The invention is further described with reference to the following detailed description and accompanying drawings.

In the present invention, all the equipment and materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified. The raw material coal used in the examples of the present invention was nakedful coal.

As shown in fig. 1, an energy-saving system for co-burning hazardous waste by using a coal-fired boiler used in various embodiments of the present invention includes a pulverized coal feeding unit, a hazardous waste feeding unit, an air supply unit, and a coal-fired boiler 11, wherein the coal-fired boiler employs a 200t/h circulating fluidized bed boiler.

The coal powder feeding unit comprises a closed coal powder bin 10 and a first feeding device 12 connected with a discharge hole of the closed coal powder bin. The dangerous waste feeding unit comprises a closed dangerous waste pit 1, a drying device 2, a crushing device 3, a crushing device 4 and a second feeding device 14 which are sequentially connected, and the second feeding device is connected with the coal-fired boiler. The air supply unit comprises an air preheater 7 and a primary fan 5 and a secondary fan 6 which are respectively connected with the air preheater. The primary air fan and the secondary air fan are respectively connected with the air preheater and the coal-fired boiler in sequence through a primary air supply pipeline 8 and a secondary air supply pipeline 9.

A mixer 13 is arranged on a primary air supply pipeline between the air preheater and the coal-fired boiler, and the mixer is connected with a first feeding device 12. The secondary air supply pipeline between the air preheater and the coal-fired boiler comprises a first branch 901 and a second branch 902, the first branch is directly connected with the air preheater and the coal-fired boiler, and the second branch is sequentially connected with the air preheater, the drying device and the coal-fired boiler.

The crushing device and the crushing device are respectively provided with a gas collecting hood 15, and the gas collecting hood, the closed pulverized coal bunker and the closed hazardous waste pit are connected with the coal-fired boiler through a gas collecting pipeline 16.

When the system operates, pulverized coal in the closed pulverized coal bunker enters the mixer through the first feeding device, is mixed with primary air which is output by the primary fan and is heated by the air preheater in the mixer, and is conveyed into the coal-fired boiler by the primary air; the oily sludge and the vinasse are mixed in a closed hazardous waste pit, then enter a drying device, are dried by secondary air which is output by a secondary fan and heated by an air preheater, and then are crushed into powder by a crushing device and a crushing device, and then are conveyed into a coal-fired boiler by a second feeding device to be mixed with coal powder for burning, so that the volume reduction, weight reduction and resource recycling of hazardous waste are realized. Volatile organic compounds and moisture generated in the drying process in the drying device enter the coal-fired boiler again along with the air supply unit through the secondary air supply pipeline to be incinerated; the gas in the closed pulverized coal bunker, the closed hazardous waste pit and the gas collected by the crushing device and the gas collecting hood on the crushing device are collected through the gas collecting pipeline and are sent into the coal-fired boiler together for combustion, so that the pollution of volatile organic compounds to the environment and the operation space in the treatment process is avoided.

Example 1:

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge and vinasse in a mass ratio of 38:15 in a closed hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, wherein the mass of the mixture fed into the drying device is 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

The results of analyzing the physicochemical properties of the oil-containing sludge and the lees are shown in tables 1 and 2.

Table 1: and analyzing the physicochemical property of the oil-containing sludge.

Table 2: and analyzing the physical and chemical properties of the vinasse.

Example 2:

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (with the water content of 30.5%) and vinasse (with the water content of 63.51%) in a mass ratio of 35:15 in a closed hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, and feeding the mixture into the drying device with the mass of 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 200 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 25:75, and the central temperature of a hearth is 900 ℃ during incineration.

Example 3:

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (water content 31.8%) and vinasse (water content 60.33%) in a mass ratio of 40:15 in a closed hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, wherein the mass of the mixture fed into the drying device is 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 250 ℃, and the ratio of primary air to secondary air is 60: 40;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 20:80, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 1 (without vinasse fired):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) the oily sludge (with the water content of 34.6%) which is the same as that in the example 1 is directly fed into a drying device, and the mixture is dried by secondary air provided by a secondary air fan, wherein the mass of the mixture fed into the drying device is 4 t/h; secondary air quantity 83527N under BMCR (maximum continuous evaporation capacity of boiler) working conditionm³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50; (2) crushing and crushing the dried oily sludge to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 2 (too much vinasse in bulk):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing the oily sludge (with the water content of 34.6%) and the vinasse (with the water content of 69.75%) which are in a mass ratio of 15:38 and are the same as those in the example 1 in a closed hazardous waste pit, feeding the mixture into a drying device, and drying the mixture by secondary air provided by a secondary air fan, wherein the mass of the mixture fed into the drying device is 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 3 (co-firing with straw instead of distillers' grains):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (with the water content of 34.6%) and straws in a mass ratio of 38:15 in a closed hazardous waste pit, enabling the mixture to enter a drying device, drying the mixture through secondary air provided by a secondary air fan, and enabling the mass of the mixture entering the drying device to be 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 4 (co-firing with bagasse instead of distillers' grains):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (with the water content of 34.6%) and bagasse in a mass ratio of 38:15 in a closed type hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, wherein the mass of the mixture fed into the drying device is 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 5 (increase of blending ratio of hazardous waste powder):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (with the water content of 34.6%) and vinasse (with the water content of 69.75%) in a mass ratio of 38:15 in a closed hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, and feeding the mixture into the drying device with the mass of 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 210 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 40:60, and the central temperature of a hearth is 900 ℃ during incineration.

Comparative example 6 (lowering secondary air temperature):

a method for blending burning hazardous waste by using the system comprises the following steps:

(1) mixing oil-containing sludge (with the water content of 34.6%) and vinasse (with the water content of 69.75%) in a mass ratio of 38:15 in a closed hazardous waste pit, feeding the mixture into a drying device, drying the mixture by secondary air provided by a secondary fan, and feeding the mixture into the drying device with the mass of 4 t/h; secondary air quantity 83527Nm under BMCR (maximum continuous evaporation capacity of boiler) working condition³The temperature of secondary air is 180 ℃, and the proportion of primary air to secondary air is 50: 50;

(2) crushing and crushing the dried mixture to 10 meshes to obtain dangerous waste powder;

(3) and (3) sending the hazardous waste powder and the coal powder into a coal-fired boiler together for incineration, wherein the mass ratio of the hazardous waste powder to the coal powder is 30:70, and the central temperature of a hearth is 900 ℃ during incineration.

The flue gas and ash components after incineration in the above examples and comparative examples were analyzed, and the results are shown in tables 3 and 4.

Table 3: and testing results of smoke components.

Table 4: and (5) testing the ash component.

As can be seen from tables 3 and 4, in the embodiments 1 to 3, the method disclosed by the invention is adopted to mix and burn the oil-containing sludge, the vinasse and the coal powder, so that the reduction of hazardous wastes can be effectively realized, and the content of each pollutant in the burned smoke meets the standard of GB 18484-2001.

In comparative example 1, only oily sludge and coal powder are mixed for burning, vinasse is not mixed for burning, and NO in smoke gas_XAnd SO₂The content is obviously improved, and the discharge amount of heavy metal is also increased; in the comparative example 2, the blending combustion proportion of the vinasse is increased, because the water content in the vinasse is higher, the secondary air can not effectively dry the dangerous waste mixture,the water content of hazardous waste powder entering the boiler is high, the burning-out of fuel is influenced, the thermal ignition loss rate of ash slag is increased, and the standard requirement is not met; in the comparative example 6, the temperature of the secondary air is reduced, the dewatering effect of hazardous waste is also influenced, the thermal ignition reduction rate of ash slag is increased, and the reduction and harmless treatment of waste are incomplete.

In comparative examples 3 and 4, straw and bagasse are used to replace vinasse and oil-containing sludge to be mixed with coal powder for burning, although NO in flue gas can also be reduced_X、SO₂And the content of pollutants is equal, but the slag bonding phenomenon can occur in the boiler, and the safety and the economical efficiency of the system operation are influenced. In the comparative example 5, the blending combustion ratio of the dangerous waste coal powder and the coal powder is improved, the content of pollutants in the flue gas is improved, and the standard requirement is not met; and the combustion efficiency is reduced, and the reduction and harmlessness of the waste are not thorough.