System for regulating and controlling low-nitrogen combustion of coal-fired boiler through plastic pyrolysis gas

Abstract

The utility model discloses a system for regulating and controlling low-nitrogen combustion of a coal-fired boiler through plastic pyrolysis gas. The system comprises a waste plastic crushing device, a plastic pyrolysis device, a DCS system, a one-way valve control device and an intelligent control system, a discharge port of the waste plastic crushing device is connected with a feed port of the plastic pyrolysis device, a gas outlet of the plastic pyrolysis device is connected to a coal-fired boiler hearth burnout area, the DCS system is located at the position of the coal-fired boiler hearth burnout area, and the one-way valve control device is connected with the DCS system. And the one-way valve control device is connected with the intelligent control system. The device has the advantages that volatile components generated by waste plastic pyrolysis can be effectively utilized to regulate and control nitrogen oxides in a boiler burnout area, and real-time detection of the nitrogen oxides and real-time regulation and control of plastic pyrolysis gas are realized.

Description

Technical Field

[0001] The utility model belongs to the field of low-nitrogen combustion of coal-fired boilers and thermal treatment of solid wastes, and in particular relates to a system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas. Background Art

[0002] Coal has always been the main primary energy source in my country. Thermal power generation accounts for 71.13% of the total power generation and is the most important and reliable energy source. When coal is burned, a large amount of nitrogen oxides will be produced, causing environmental pollution. The new version of the "Boiler Air Pollutant Emission Standard" stipulates that the nitrogen oxide emissions should be reduced to 80mg / m 3 At the same time, in the treatment of solid waste, the effective recycling of waste plastics has always been a hot topic and one of the problems to be solved urgently. During the pyrolysis process of plastics, pyrolysis gas containing hydrogen, hydrocarbons and other products will be produced. This type of pyrolysis gas can effectively reduce nitrogen oxides and will have a wide range of applications for low-nitrogen combustion of pulverized coal in coal-fired boilers. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a system for regulating low-nitrogen combustion of a coal-fired boiler by means of plastic pyrolysis gas, which effectively overcomes the defects of the prior art.

[0004] The technical solution of the utility model to solve the above technical problems is as follows:

[0005] A system for regulating low-nitrogen combustion of a coal-fired boiler by using plastic pyrolysis gas, comprising waste plastic crushing equipment, a plastic pyrolysis device, a coal-fired boiler furnace, a DCS system and an intelligent control system;

[0006] The plastic crushing equipment has a feed inlet and a discharge port, the discharge port is connected to the feed inlet of the plastic pyrolysis device through a pipeline, the gas outlet of the plastic pyrolysis device is connected to the burnout zone of the coal-fired boiler furnace through a pipeline, and the DCS system is arranged on the inner wall of the coal-fired boiler furnace and connected to the intelligent control system;

[0007] The plastic pyrolysis device comprises a pyrolysis chamber, a pyrolysis mechanism is arranged in the pyrolysis chamber, a feed port is arranged at the upper end of the pyrolysis chamber, a discharge port is arranged at the lower end of the pyrolysis chamber, a volatile matter outlet is arranged in the pyrolysis chamber, and the volatile matter outlet of the pyrolysis chamber is connected to the burnout zone of the furnace of the coal-fired boiler through a pipeline.

[0008] A further improvement of the utility model is that a one-way valve and a one-way valve control device are arranged in the pipeline connecting the plastic pyrolysis device and the furnace of the coal-fired boiler.

[0009] A further improvement of the utility model is that the amount of pyrolysis gas introduced is regulated by the one-way valve and the one-way valve control device according to the DCS system feedback and the intelligent control system.

[0010] A further improvement of the utility model is that the plastic pyrolysis device also includes a pyrolysis coke collection device.

[0011] A further improvement of the utility model is that the plastic pyrolysis device also includes a pyrolysis gas purge device for continuously introducing air to blow the plastic pyrolysis gas into the furnace of the coal-fired boiler.

[0012] A further improvement of the utility model is that the plastic crushing equipment is used to crush waste plastics into powder.

[0013] A further improvement of the utility model is that the pyrolysis temperature in the plastic pyrolysis device is in the range of 400-600°C.

[0014] The utility model is further improved in that the setting value of the nitrogen oxide content in the furnace of the coal-fired boiler is 300-500 mg / Nm 3 .

[0015] The utility model has at least the following beneficial technical effects:

[0016] Since the volatile matter after plastic pyrolysis contains a large number of hydrocarbon small molecular groups with strong reducing properties, it can form graded combustion and reduce the generated nitrogen oxides when introduced into the coal-fired boiler. Therefore, based on the requirement of regulating the low-nitrogen combustion of coal-fired boilers with plastic pyrolysis gas, a device system that can effectively couple plastic pyrolysis treatment and coal-fired boiler combustion is designed. According to the nitrogen oxide generation during coal-fired boiler combustion, the amount of plastic pyrolysis gas introduced is regulated on site, which can effectively utilize the volatile matter generated by plastic pyrolysis to regulate the nitrogen oxides generated in the furnace of the coal-fired boiler and reduce the nitrogen oxide generation of the coal-fired boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model is a structural schematic diagram of a system for regulating low-nitrogen combustion in a coal-fired boiler using plastic pyrolysis gas.

[0018] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0019] 1. Waste plastic crushing equipment; 2. Plastic pyrolysis device; 3. Coal-fired boiler furnace; 4. DCS system; 5. Intelligent control system; 6. One-way valve; 7. One-way valve control device; 8. Pyrolysis chamber; 9. Pyrolysis coke collection device; 10. Pyrolysis gas purge device. DETAILED DESCRIPTION

[0020] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0021] Example: Figure 1As shown, a system for regulating low-nitrogen combustion of a coal-fired boiler by using plastic pyrolysis gas in this embodiment includes a waste plastic crushing device 1, a plastic pyrolysis device 2, a coal-fired boiler furnace 3, a DCS system 4 and an intelligent control system 5. The plastic crushing device 1 has a feed inlet and a discharge port, and the discharge port is connected to the feed inlet of the plastic pyrolysis device 2 through a pipeline. The gas outlet of the plastic pyrolysis device 2 is connected to the burnout zone of the coal-fired boiler furnace 3 through a pipeline. The DCS system 4 is arranged on the inner wall of the coal-fired boiler furnace 3 and is connected to the intelligent control system 5.

[0022] The plastic pyrolysis device 2 includes a pyrolysis chamber 8, in which a pyrolysis mechanism is provided. The upper end of the pyrolysis chamber 8 is provided with a feed inlet, the lower end is provided with a discharge port, and the pyrolysis chamber 8 is provided with a volatile matter outlet. The volatile matter outlet of the pyrolysis chamber 8 is connected to the burnout zone of the coal-fired boiler furnace 3 through a pipeline.

[0023] The pipeline connecting the plastic pyrolysis device 2 and the coal-fired boiler furnace 3 is provided with a check valve 6 and a check valve control device 7. The amount of pyrolysis gas introduced is regulated by the check valve 6 and the check valve control device 7 according to the feedback of the DCS system 4 and the intelligent control system 5.

[0024] The plastic pyrolysis device 2 also includes a pyrolysis coke collection device 9 .

[0025] The plastic pyrolysis device 2 further comprises a pyrolysis gas blowing device 10 for continuously introducing air to blow the plastic pyrolysis gas into the furnace 3 of the coal-fired boiler.

[0026] The actual production process of the utility model is as follows:

[0027] Waste plastics enter the plastic crushing equipment 1, are crushed into powder, and then enter the plastic pyrolysis device 2. The pyrolysis gas generated by the pyrolysis of plastics is carried by the air in the pyrolysis gas purge device 10 into the burnout zone of the coal-fired boiler furnace 3. The amount of pyrolysis gas introduced is regulated by the one-way valve 6 and the one-way valve control device 7 according to the feedback of the DCS system 4 and the intelligent control system 5. The whole system structure is reasonably designed and can effectively use the plastic pyrolysis gas for boiler low-nitrogen combustion.

[0028] It should be noted that: in this embodiment, the pyrolysis temperature in the plastic pyrolysis device 2 is in the range of 400-600°C.

[0029] As a preferred embodiment, the pipeline between the plastic pyrolysis device 2 and the coal-fired boiler furnace 3 is provided with an insulation layer to keep the pipeline temperature higher than 150° C. to avoid condensation and blockage of the pipeline by volatile matter.

[0030] In the above embodiment, the set value of the nitrogen oxide content in the furnace 3 of the coal-fired boiler is 300-500 mg / Nm 3The DCS system detected that the nitrogen oxide content in the furnace of the coal-fired boiler exceeded the set value of 300-500mg / Nm 3 range, it will be fed back to the intelligent control system 5, which will adjust the one-way valve 6 through the one-way valve control system 7 to pass the plastic pyrolysis gas. When the nitrogen oxide content is set to 300-500mg / Nm 3 When the value is within the range or below, the one-way valve 6 is closed.

[0031] Of course, in this embodiment, a pyrolysis coke collection device 9 can be configured at the pyrolysis coke outlet, and the pyrolysis coke collection device 9 is connected to the pyrolysis coke outlet of the plastic pyrolysis device 2 to realize the collection and processing of pyrolysis coke. Although the embodiments of the utility model have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the utility model. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the utility model.

Claims

1. A system for regulating low-nitrogen combustion in coal-fired boilers using plastic pyrolysis gas, characterized in that: It includes waste plastic crushing equipment (1), plastic pyrolysis device (2), coal-fired boiler furnace (3), DCS system (4) and intelligent control system (5); The plastic crushing device (1) has a feed inlet and a discharge port, the discharge port is connected to the feed inlet of the plastic pyrolysis device (2) through a pipeline, the gas outlet of the plastic pyrolysis device (2) is connected to the burnout zone of the coal-fired boiler furnace (3) through a pipeline, and the DCS system (4) is arranged on the inner wall of the coal-fired boiler furnace (3) and connected to the intelligent control system (5); The plastic pyrolysis device (2) comprises a pyrolysis chamber (8), a pyrolysis mechanism is arranged in the pyrolysis chamber (8), a feed inlet is arranged at the upper end of the pyrolysis chamber (8), a discharge outlet is arranged at the lower end of the pyrolysis chamber (8), a volatile matter outlet is arranged in the pyrolysis chamber (8), and the volatile matter outlet of the pyrolysis chamber (8) is connected to the burnout zone of the furnace (3) of a coal-fired boiler through a pipeline.

2. A system for regulating low-nitrogen combustion in coal-fired boilers using plastic pyrolysis gas according to claim 1, characterized in that: A one-way valve (6) is provided in the pipeline connecting the plastic pyrolysis device (2) and the furnace (3) of the coal-fired boiler.

3. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 2, characterized in that: A one-way valve control device (7) is also provided in the pipeline connecting the plastic pyrolysis device (2) and the furnace (3) of the coal-fired boiler.

4. A system for regulating low-nitrogen combustion in coal-fired boilers by using plastic pyrolysis gas according to claim 3, characterized in that: The amount of pyrolysis gas introduced is regulated by a one-way valve (6) and a one-way valve control device (7) according to feedback from a DCS system (4) and an intelligent control system (5).

5. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 1 is characterized in that: The plastic pyrolysis device (2) also includes a pyrolysis coke collection device (9).

6. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 1, characterized in that: The plastic pyrolysis device (2) also includes a pyrolysis gas purge device (10) for continuously introducing air to blow the plastic pyrolysis gas into the furnace (3) of the coal-fired boiler.

7. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 1, characterized in that: The plastic crushing equipment (1) is used to crush waste plastic into powder.

8. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 1, characterized in that: The pyrolysis temperature in the plastic pyrolysis device (2) is in the range of 400-600°C.

9. The system for regulating low-nitrogen combustion of coal-fired boilers by using plastic pyrolysis gas according to claim 1, characterized in that: The set value of nitrogen oxide content in the furnace (3) of the coal-fired boiler is 300-500 mg / Nm 3 .

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