CN2606262Y - A low-pollution waste incineration system - Google Patents

Abstract

The utility model provides a low-pollution refuse burning system, comprising a rotary kiln (2), a secondary combustion chamber (7), a high temperature air combustion device and an ash melting treatment device (1), wherein, one end of the rotary kiln (2) is connected with the secondary combustion chamber (7), while the other end is connected with the ash melting treatment device (1); the high temperature air combustion device is connected respectively with the rotary kiln (2) and the secondary combustion chamber (7). The low-pollution refuse burning system adopts an air inlet sectionalizing rotary kiln as a primary combustion chamber and heats air by using the waste hot of flue gas so as to make the system achieve the best combustion efficiency and reduce the amount of auxiliary fuel; meanwhile, improves combustion temperature and reduces the discharge of dioxin, furan and other pollutants in flue gas; additionally, applies melting treatment on slag and fly ash, and effectively controls the discharge of dioxin, furan and other pollutants. Therefore, the utility model has the advantages of high treatment efficiency and good environmental protection effect, can be widely applied to city domestic refuse treatment, and is broad in application prospect.

Description

A low-pollution waste incineration system

Technical field

The utility model relates to garbage treatment technology, in particular to a low-pollution garbage incineration system.

Background technique

The dumping of urban garbage has the following obvious hazards: polluting water sources, polluting farmland and soil, polluting the atmosphere, becoming a breeding source for mosquitoes, mice, and pathogens, and occupying land. Municipal solid waste usually contains: paper, cloth, plastic, rubber, kitchen waste, vegetation, bricks, sand, metal, glass, etc. However, the content of each component varies with the living habits, economic development level, and climate conditions of each region. In developed countries, the output of municipal solid waste is large, of which food waste, paper, cloth, plastic and other organic matter account for a large proportion, with high combustible content and high calorific value. Generally speaking, the content of inorganic substances in garbage in our country is relatively high, but in recent years, with the improvement of living standards and the popularization of city gas, the organic components in garbage are also gradually increasing, with a decrease in bulk density and an increase in calorific value. At the same time, the output of garbage is also increasing year by year. These characteristics of garbage at home and abroad show that the traditional landfill and composting treatment can no longer meet the needs, because the two methods have poor volume reduction and volume reduction effects, while the incineration method has been developed rapidly due to its advantages.

The furnace types suitable for solid waste incineration developed abroad mainly include: Martin Furnace, two-stage furnace, two-chamber furnace, rotary kiln, fluidized bed, refuse derived fuel, controlled air oxidation, direct-current arc melter, thermal plasma arc vitrification and high temperature or Low temperature cracking (high/low temperature decomposition), etc. A comparison of several common waste incinerator types is as follows:

(1) Mechanical grate type: It is mainly used in Europe, the United States, and Japan. The processing capacity is above 200t/d. The design, manufacturing, operation and maintenance technologies are mature. Except for bulky waste, it is not classified and shredded. Its advantages are: suitable for large capacity, easy to handle pollution, and reliable combustion; disadvantages are: high cost, high operation and maintenance costs, continuous operation, and high technical requirements for operation and operation.

(2) Modular type: mainly used in the United States and Japan, the processing capacity is below 200t/d, and the design, manufacturing, operation and maintenance technology is mature, so it cannot handle bulky waste. Its advantages are: suitable for small capacity, simple structure, movable device and high mobility; disadvantages are: incomplete combustion, low combustion efficiency, short service life, and high average construction cost.

(3) Rotary kiln type: mainly used in the United States and Denmark, with a processing capacity of more than 200t/d, limited suppliers, and no need for classification and crushing except for bulky waste. Its advantages are: good garbage mixing and drying, suitable for medium and large capacity, high temperature combustion, and small residual ash particles. The disadvantages are: the connection transmission device is complicated, and the refractory material in the furnace is easily damaged.

(4) Fluidized bed type: mainly used in Japan, the processing capacity is below 150t/d, the suppliers are limited, and it needs to be classified and crushed to below 5cm. Its advantages are: suitable for medium capacity, low combustion temperature, good thermal conductivity, low pollution, and good combustion efficiency. The disadvantages are: high operating technology, limited fuel types, need to add flow media, small feed particles, high power required per unit of processing capacity, and hearth materials are easily eroded and damaged.

In practice, people have gradually realized that direct incineration has the following disadvantages:

(1) Garbage has high moisture content and is difficult to burn stably and completely;

(2) Emission of chlorinated dibenzodioxins and chlorinated dibenzofurans;

(3) The technology of domestic grate manufacturing is immature, and the imported grate is expensive;

(4) High temperature corrosion of waste heat boiler equipment.

Therefore, whether it can burn stably and completely under the condition of no or less oil input; can it effectively control corrosion and the formation of pollutants such as dioxins and furans; key to technological development.

Contents of Invention

The purpose of the utility model is to overcome the disadvantages and deficiencies of the prior art, to provide a fuel tank that can effectively improve combustion efficiency, reduce the amount of auxiliary fuel, reduce the discharge of pollutants such as dioxin and furan in the flue gas, and reduce the impact on environmental pollution. Low pollution waste incineration system.

The purpose of this utility model is achieved through the following technical solutions: the low-pollution waste incineration system includes a rotary kiln, a second combustion chamber, a high-temperature air combustion device, and ash melting treatment device. One end of the rotary kiln is connected with the second combustion chamber, and the other end is connected with the second combustion chamber. The ash melting treatment device is connected, and the high-temperature air combustion device is respectively connected with the rotary kiln and the second combustion chamber.

The rotary kiln is divided into four sections, and stainless steel rollers are used to connect and seal the sections. Among them, the first and third sections are relatively short, which are fixed feeding section and air inlet section, which are used for feeding and supplying air; the second and fourth sections are rotating sections, driven by gears or rollers, and the gears or rollers are Driven by a motor, the speed of the motor is steplessly adjustable, and the actual operation is controlled at 3 to 5 rpm. The inclination angle of the rotary kiln body is 2°. The end of the rotary kiln is connected to a high-temperature air combustion device, and the air inlet section in the middle is connected to a blower for air supply. The blower is driven by a motor, and the speed of the motor can be adjusted according to needs to adjust the air supply volume.

At present, the existing rotary kiln is incinerated by air supply at one end, and most of them are arranged downstream, so that the temperature in the rotary kiln is low and the combustion is unstable; The amount of air required is not large, but a higher gas temperature is required to facilitate rapid heating and drying. Therefore, in the first combustion chamber, the flow of air and flue gas is opposite to the forward direction of the solid, and a countercurrent arrangement is adopted; due to the strong intermediate reaction, an additional configuration Wind, supplementary oxygen; the rotary kiln with graded air distribution can overcome the shortcomings of traditional rotary kiln air distribution and the organization of combustion conditions in the first combustion chamber, and optimize the air supply temperature and air supply volume according to the combustion characteristics in the rotary kiln. It is beneficial to improve the temperature distribution and waste incineration conditions in the rotary kiln, so as to achieve the effect of stable and complete combustion of waste.

The flue gas inlet of the second combustion chamber is tangent to the casing of the second combustion chamber; that is, the second combustion chamber adopts a tangential air intake method, and a swirl combustion working condition is organized in the second combustion chamber.

In existing pyrolysis and gasification furnaces, such as the secondary combustion chamber of the CAO system with controlled oxygen combustion, axial or radial air intake is adopted, and there is no swirling flow in the secondary combustion chamber, so that the supply of the secondary combustion chamber The mixture of wind and combustible gas is not good, and there are combustion dead angles and some low-temperature areas, which are not conducive to combustion. At the same time, the residence time of combustibles in the secondary combustion chamber is not enough. If the length of the secondary combustion chamber is increased, the furnace body will be huge and the investment will increase. ; In this technical solution, the second combustion chamber adopts a tangential air intake method, and the swirl combustion working condition is organized in the second combustion chamber to strengthen the stirring and mixing in the furnace, prolong the residence time of combustibles in the furnace, and make the combustible components of the flue gas It can be fully burned and is conducive to the decomposition of pollutants such as dioxins and furans.

The high-temperature air combustion device includes an air preheater and a waste heat boiler, and the waste heat boiler is connected with the secondary combustion chamber through the air preheater.

The existing waste incineration treatment equipment adopts the arrangement of "incinerator-waste heat boiler-air preheater", or uses steam to preheat the air. The air preheating temperature is low, and some even do not preheat the air, and the waste contains water. The rate is high, which is easy to cause low furnace temperature, difficulty in ignition, unstable combustion, and incomplete combustion; in addition, the combustion temperature is low, and the trace organic compounds such as dioxin and furan cannot be decomposed, and are discharged into the atmosphere from the flue gas , forming secondary pollution. In this technical solution, the layout of "incinerator-air preheater-waste heat boiler" is adopted, so that the waste heat of flue gas generated by incineration of garbage can first heat the air, which can greatly increase the temperature of the air supply; then, use high-temperature air to incinerate Garbage, increase the reaction temperature, reduce the consumption of auxiliary fuel, and reduce the emission of pollutants such as dioxins and furans in the flue gas.

The ash slag melting treatment device includes a shell, an ash hopper, a fuel burner, a smoke outlet, and a slag outlet. The ash hopper and the fuel burner pass through the upper surface of the shell and are fixedly connected with the shell. On the side of the upper end face, the slag port is located on the bottom side of the shell. The principle of this ash melting treatment device is: ash and fly ash fall from the ash hopper into the furnace in the casing, fuel oil is injected from the fuel burner to melt the ash and fly ash, and the processed flue gas is discharged from the The smoke is discharged from the exhaust port, and the waste residue is discharged from the slag port.

In some existing waste incinerators, including Martin furnace, fluidized bed, CAO, rotary kiln, etc., the ablation amount in ash is usually higher than 5%, which means that the combustion is not sufficient and the availability of slag is also very low. In addition, trace amounts of organic compounds such as dioxins and furans in ash and fly ash have not been effectively controlled, and are directly discharged into soil, water sources and the atmosphere, causing serious secondary pollution. In this technical solution, a high-temperature ash melting treatment device is used to process ash and fly ash, and the ash and fly ash are melted to eliminate the discharge of pollutants such as dioxin and furan in the ash and fly ash; at the same time , the molten ash can be used as construction and road construction materials.

Compared with the prior art, the utility model has the following advantages and effects: the low-pollution garbage incineration system adopts a rotary kiln with segmental air intake as a combustion chamber, and uses the waste heat of the flue gas to heat the air, so that the system can achieve the best combustion efficiency and reduce the amount of auxiliary fuel; at the same time, increase the combustion temperature to reduce the emission of pollutants such as dioxin and furan in the flue gas; in addition, melt the ash and fly ash to effectively control the ash and fly ash Discharge of pollutants such as dioxin, furan, etc. Therefore, it has the advantages of high treatment efficiency and good environmental protection effect, and can be widely used in the treatment of urban domestic waste, with a wide application prospect.

Description of drawings

Fig. 1 is a system flow chart of the low-pollution waste incineration system of the present invention.

Fig. 2 is a schematic structural diagram of the rotary kiln in the low-pollution waste incineration system shown in Fig. 1 .

Fig. 3 is a schematic structural view of the secondary combustion chamber in the low-pollution waste incineration system shown in Fig. 1 .

Fig. 4 is a schematic structural view of the air preheater in the low-pollution waste incineration system shown in Fig. 1 .

Figure 5 is a diagram of the ash melting treatment device in the low-pollution waste incineration system shown in Figure 1

Detailed ways

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto.

Example

Fig. 1～Fig. 5 has shown the specific structure of the present utility model, and by Fig. 1, this waste incineration system comprises rotary kiln (one combustion chamber) 2, two combustion chambers 7, air preheater 8, waste heat boiler 9, ash The slag melting treatment device 1, one end of the rotary kiln 2 is connected with the second combustion chamber 7, the other end is connected with the ash melting treatment device 1, the waste heat boiler 9 is connected with the second combustion chamber 7 through the air preheater 8, and the air is preheated Device 8 is connected with one end of rotary kiln 2 at the same time. In addition, in Fig. 1, 3 is a blower, 4 is a feeding mechanism, 5 is a garbage hopper, 6 is a fuel nozzle, and 10 is a chimney.

The structure of the rotary kiln 2 is divided into four sections as shown in Figure 2, and each section is connected by stainless steel rollers and sealed with a sealing cover; wherein, the first and third sections are shorter and are fixed feed sections 2-1 And the air inlet section 2-3 is used for feeding and supplying air; the second and fourth sections 2-2 and 2-4 are rotating sections, driven by gears or rollers, which are driven by motors, and the motor speed Stepless adjustable, controlled at 3 to 5 rpm during actual operation; the inclination angle of the rotary kiln 2 furnace body is 2°, and the air preheater 8 connected to the end of the rotary kiln 2 is fed with high-temperature air for preheating, and the middle part The air inlet section 2-3 is connected to the blower 3 for air supply, and the blower 3 is driven by a motor whose speed can be adjusted according to needs to adjust the air supply volume.

The structure of the second combustion chamber 7 is as shown in Figure 3, including a housing 7-1, a smoke inlet 7-2, a smoke outlet 7-3, and an oil inlet 7-4, and the housing 7-1 is formed by a casing 7 -1A and refractory layer 7-1B, the flue gas inlet 7-2 is located at a position tangent to the shell 7-1, the flue gas outlet 7-3 and the oil inlet 7-4 are respectively located at the two sides of the shell 7-1 end.

The structure of the air preheater 8 is shown in Figure 4, the two ends of the housing 8-1 are provided with a flue gas inlet 8-2 and a flue gas outlet 8-3, and one side of the housing 8-1 is provided with an air inlet 8-4 and an air outlet 8-5; the shell 8-1 is provided with a ceramic heat exchange tube 8-6, the inside of the heat exchange tube 8-6 is an air channel, and the outside of the heat exchange tube 8-6 is a flue gas channel.

The ash melting device 1 is shown in Figure 5, comprising a housing 1-1, a fuel burner 1-2, an ash hopper 1-3, a smoke outlet 1-4, a slag outlet 1-5, an ash hopper 1 -3 and the fuel burner 1-2 pass through the upper end surface of the housing 1-1 and are fixedly connected with the housing 1-1, the smoke outlet 1-4 is located on the side of the upper end surface of the housing 1-1, and the slag outlet 1-5 Located on the bottom side of the housing 1-1.

The working principle of this low-pollution waste incineration system is: the system layout adopts the layout of "incinerator-air preheater-waste heat boiler", and an air preheater 8 is installed between the second combustion chamber 7 and the waste heat boiler 9 to recover part of the smoke. Gas waste heat, make full use of high-temperature flue gas to heat the air entering the furnace, the temperature reaches above 600°C, raise the reaction temperature of the first combustion chamber 2 to above 900°C, and the reaction temperature of the second combustion chamber 2 to above 1000°C, thereby reducing the dioxin in the flue gas , furan and other pollutants, while making the garbage stable and complete combustion, reducing the consumption of auxiliary fuel. After being treated in the first combustion chamber 2, the mechanical incomplete combustion loss q4 is below 3%; the combustible gas and smoke from the first combustion chamber 2 enter the second combustion chamber 7 in a tangential flow, and the intake velocity is maintained at 6m /s or more to ensure a certain degree of swirl; the second combustion chamber 7 is fed with high-temperature air above 600°C. Stable combustion, the swirling flow condition can strengthen the mixing in the furnace, thereby strengthening the combustion, and prolonging the residence time of combustibles in the second combustion chamber 7, ensuring that the chemical incomplete combustion loss q3 after passing through the second combustion chamber 7 is below 0.2%; The ash from the first combustion chamber 2 and the fly ash collected from the dust collector or the bottom of the chimney enter the ash melting treatment device 1. This chamber uses oil as fuel and melts the ash and fly ash at a temperature above 1500°C. Completely eliminate pollutants such as dioxins and furans in ash residue and fly ash. After passing through the ash melting treatment device, the ablation amount of the ash is below 0.1%.

Claims (5)

1, a kind of low pollution rubbish CIU, it is characterized in that: comprise rotary kiln (2), dual firing chamber (7), typed high temperature air burning device, ash melting treating apparatus (1), rotary kiln (2) one ends are connected with dual firing chamber (7), the other end is connected with ash melting treating apparatus (1), and typed high temperature air burning device is connected with dual firing chamber (7) with rotary kiln (2) respectively.

2, refuse burning system according to claim 1 is characterized in that: described rotary kiln (2) is divided into four sections, and each intersegmental employing stainless steel running roller connects and sealing; First and third section is fixing feed zone (2-1) and wind inlet section (2-2), and second, four section is rotational segment (2-2,2-4), is connected with gear or running roller.

3, low pollution rubbish CIU according to claim 1 is characterized in that: (7) gas approach (7-2) of described dual firing chamber is tangent with the housing (7-1) of dual firing chamber (7).

4, low pollution rubbish CIU according to claim 1 is characterized in that: described typed high temperature air burning device comprises air preheater (8) and waste heat boiler (9), and waste heat boiler (9) is connected with dual firing chamber (7) by air preheater (8).

5, low pollution rubbish CIU according to claim 1, it is characterized in that: described ash melting treating apparatus (1) comprises housing (1-1), oil burner (1-2), ash bucket (1-3), exhaust opening (1-4), cinder notch (1-5), ash bucket (1-3) and oil burner (1-2) pass housing (1-1) upper surface and fixedly connected with housing (1-1), exhaust opening (1-4) is positioned at housing (1-1) upper surface one side, and cinder notch (1-5) is positioned at housing (1-1) bottom one side.

Images