Waste incineration flue gas online monitoring system

Abstract

The utility model belongs to the field of flue gas on-line monitoring, and particularly discloses a waste incineration flue gas on-line monitoring system, which comprises a sampling unit, a purging and standard gas unit, a sample introduction unit and an on-line monitor, and is characterized in that the sampling unit comprises a sampling point, a first control valve, a first sampling pump and a second control valve which are connected in sequence; the second control valve is connected with the sampling unit; the first sampling pump is also connected with the tail gas processor; the purging and standard gas unit comprises a three-way electromagnetic valve, a standard gas assembly, a purging gas assembly, a rotor flow meter and a second sampling pump, a port I of the three-way electromagnetic valve is connected with the standard gas assembly and the purging gas assembly, a port II of the three-way electromagnetic valve is sequentially connected with the rotor flow meter, a port III of the three-way electromagnetic valve and the sampling unit, and one end of the second sampling pump is connected with the rotor flow meter. The other end is connected with the tail gas treater; and the sample introduction unit is connected with the online monitor. The system can automatically execute the working process of purging, stabilizing, collecting, stabilizing and calibrating, so as to realize the online monitoring of the waste incineration flue gas.

Description

Technical Field

[0001] The present application relates to the field of online flue gas monitoring, and more specifically, to an online flue gas monitoring system for waste incineration. Background Art

[0002] With the development of the economy and society and the continuous improvement of people's living standards, the generation and emission of industrial solid waste, hazardous waste, urban domestic waste and medical waste are also increasing year by year, and the safe disposal of solid waste faces major challenges. The traditional treatment method based on landfill has secondary pollution problems and safety hazards. Landfill occupies land resources and cannot be reused. Incineration has the advantages of reduction, harmlessness and resource utilization. In recent years, it has gradually replaced landfill and become an important method of solid waste disposal vigorously developed by countries around the world. However, in the process of solid waste incineration, toxic and harmful substances such as acidic gases, fly ash, heavy metals and organic compounds will inevitably be released. The emission of persistent organic pollutants represented by dioxins has attracted widespread attention from countries around the world.

[0003] The traditional method for dioxin detection is the EPA-1613 method recommended by the U.S. Environmental Protection Agency (EPA), which uses isotope dilution high-resolution gas chromatography / high-resolution mass spectrometry (HRGC / HRMS) technology to analyze 4-8 chloro-PCDD / Fs. The standard method for determining dioxins from fixed sources includes complex sampling, Soxhlet extraction, purification, volume determination, and analysis. This method is accurate but time-consuming (more than one week), and the cost of detection is very high. Generally, only 1-2 spot checks can be conducted on waste incinerators each year. Therefore, this method cannot meet the public's requirements for real-time information on dioxin emissions, nor can it adjust incinerators based on real-time dioxin data to control dioxin emissions. Dioxin online monitoring technology is of great significance to the development of dioxin emission monitoring and emission reduction control technologies. Utility Model Content

[0004] In view of the defects of the prior art, the present application provides an online monitoring system for waste incineration flue gas, aiming to solve the problem that the existing dioxin monitoring method cannot perform real-time monitoring.

[0005] The present application provides an online monitoring system for waste incineration flue gas, which specifically includes a sampling unit, a purge and standard gas unit, a sampling unit and an online monitor, wherein: the sampling unit includes a sampling point, a first control valve, a first sampling pump and a second control valve connected in sequence according to the gas flow direction, the second control valve is connected to the sampling unit, and the first sampling pump is also connected to the exhaust gas processor; the purge and standard gas unit includes a three-way solenoid valve, a standard gas component, a purge gas component, a rotor flowmeter and a second sampling pump, the I port of the three-way solenoid valve is respectively connected to the standard gas component and the purge gas component, the II port of the three-way solenoid valve is connected to the rotor flowmeter, the III port of the three-way solenoid valve is connected to the sampling unit, one end of the second sampling pump is connected to the rotor flowmeter (10), and the other end thereof is connected to the exhaust gas processor; the sampling unit is connected to the online monitor.

[0006] Compared with the prior art, the above technical scheme conceived by the present application, since the present application sets up a sampling unit, a standard gas unit and a sampling unit, and optimizes the specific structure of the standard gas unit, can automatically execute the work process of purge-stabilization-collection-stabilization-calibration, thereby realizing online monitoring of waste incineration flue gas.

[0007] As a further preferred embodiment, the waste incineration flue gas online monitoring system includes more than two sampling units, and the access positions of the sampling points in each sampling unit include after the boiler, after the economizer, after the deacidification tower, after the bag filter, before the SCR device, after the SCR device, before the SNCR device, after the SNCR device, and at the chimney outlet.

[0008] As further preferred, the sampling unit comprises a sampling capillary, one end of which is connected to the sample delivery unit and the purge and standard gas unit through a flue gas pipeline, and the other end of which is connected to an online monitor.

[0009] As a further preference, the various devices in the sampling unit are connected via a flue gas pipeline.

[0010] As a further preference, the outer side of the flue gas pipeline is coated with a heat-insulating member.

[0011] As a further preference, at least one filter is arranged inside the flue gas pipeline.

[0012] As a further preference, the standard gas assembly includes standard gas and a first mass flow meter and a control component, and the first mass flow meter and the control component are connected to port I of the three-way solenoid valve.

[0013] As further preferred, the standard gas is one or more of monochlorobenzene, dichlorobenzene, trichlorobenzene, benzene, toluene, xylene, dichloroethylene, tetrachloroethylene and hexachlorobutadiene.

[0014] As further preferred, the purge gas assembly includes a purge gas and a second mass flow meter and a control component, and the second mass flow meter and the control component are connected to port I of the three-way solenoid valve.

[0015] As further preferred, the purge gas is one or more of nitrogen, helium and air.

[0016] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art:

[0017] 1. This application sets a sampling unit, a standard gas unit and a sample injection unit, and optimizes the structure of the standard gas unit, so as to automatically execute the work flow of purge-stabilization-collection-stabilization-calibration, thereby realizing the online monitoring of waste incineration flue gas, ensuring the accuracy, stability and convenience of online monitoring. At the same time, this application directly introduces the waste incineration flue gas into the analysis and detection instrument, without the need for complex sampling and pre-treatment, which can effectively reduce the detection cost;

[0018] 2. In particular, the present application can realize online monitoring of flue gas at different locations by setting more than two sampling units and optimizing the access positions of the sampling points, making it easier to adjust the incineration parameters later, and has the advantages of simple operation and practical effectiveness;

[0019] 3. In addition, the present application can avoid pipeline condensation and adsorption problems by setting up insulation parts on the outside of the flue gas pipeline, thereby ensuring the accuracy of the monitoring data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a waste incineration flue gas online monitoring system provided in an embodiment of the present application;

[0021] Figure 2 is a schematic diagram of a power plant provided in an embodiment of the present application;

[0022] Figure 3 It is a typical spectrum of the SCR inlet flue gas and the SCR outlet flue gas in Example 4 of the present application;

[0023] Figure 4 This is a dynamic emission characteristic diagram of benzene series in the SCR inlet flue gas and the SCR outlet flue gas over time in Example 4 of the present application.

[0024] In all the drawings, the same figure marks are used to represent the same elements or structures, among which: 1-sampling point, 2-flue gas pipeline, 3-insulation part, 4-first control valve, 5-first sampling pump, 6-exhaust processor, 7-filter plate, 8-standard gas, 9-first mass flow meter and control part, 10-rotor flowmeter, 11-three-way solenoid valve, 12-injection capillary, 13-online monitor, 14-purge gas, 15-second mass flow meter and control part, 16-second control valve, 17-second sampling pump, 18-boiler, 19-desulfurization tower, 20-bag collector, 21-SCR device, 22-chimney. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] like Figure 1 As shown, the present application provides an online monitoring system for waste incineration flue gas, which specifically includes a sampling unit, a purge and standard gas unit, a sampling unit and an online monitor 13, wherein: the sampling unit includes a sampling point 1, a first control valve 4, a first sampling pump 5 and a second control valve 16 connected in sequence according to the gas flow direction, the second control valve 16 is connected to the sampling unit, and the first sampling pump 5 is also connected to the exhaust gas processor 6, and the excess flue gas will be sent to the exhaust gas processor 6 for processing; the purge and standard gas unit includes a three-way solenoid valve 11, a standard gas component, a purge gas The three-way solenoid valve 11 has a port I connected to the standard gas component and the purge gas component respectively, and a port II connected to the rotor flowmeter 10. The second sampling pump 17 is used as a secondary pump to introduce the flue gas into the sampling unit. One end of the second sampling pump 17 is connected to the rotor flowmeter 10, and the other end is connected to the exhaust gas processor 6 to send excess flue gas into the exhaust gas processor 6 for treatment. The port III of the three-way solenoid valve 11 is connected to the sampling unit; the sampling unit is connected to the online monitor 13.

[0027] During long-term online monitoring, in order to facilitate the operation of monitoring personnel, extend the service life of the instrument, and ensure the stability of monitoring, the online monitor 13 is usually placed in a room with a stable and controllable environment. Therefore, the present application designs a complete online monitoring system to effectively introduce the flue gas from the waste incineration system into the online monitor 13, overcoming problems such as adsorption and condensation during long-distance transmission of flue gas.

[0028] The waste incineration flue gas online monitoring system provided by the present application has a purge mode, a sampling mode and a calibration mode when working. When the port I of the three-way solenoid valve 11 is connected to the port III, it is in the standard mode or the purge mode, and the standard gas component or the purge gas component passes the standard gas into the online monitor 13 through the sampling unit for calibration or purge gas for purge; when the port II of the three-way solenoid valve 11 is connected to the port III, it is in the sampling mode, and the second sampling pump 17 is used as a secondary pump to send the flue gas into the online monitor 13 through the sampling unit to realize the online monitoring of the flue gas, and then the purge gas, flue gas and standard gas can be alternately introduced into the online monitor 13, and the purge-stabilization-collection-stabilization-calibration sequence is executed, thereby realizing the online monitoring of waste incineration flue gas. In the purge mode, the purge time is 1min to 30min, and the purge gas flow rate is 100mL / min to 1000mL / min. In sampling mode, the airflow needs to be stabilized before signal acquisition, and the stabilization time is one of 10s, 20s, 30s, 40s, 50s, and 60s. The acquisition time of flue gas sample signal is 1min to 30min. In calibration mode, the airflow needs to be stabilized before calibration, and the stabilization time is one of 10s, 20s, 30s, 40s, 50s, and 60s. The calibration gas signal acquisition time is 1s to 60s. The calibration gas flow rate is 100mL / min to 3000mL / min, and the calibration gas concentration is 10ppb to 1000ppb.

[0029] Furthermore, the waste incineration flue gas online monitoring system includes more than two sampling units, and the access positions of the sampling points 1 in each sampling unit include after the boiler 18, after the economizer, after the deacidification tower 19, after the bag filter 20, before the SCR device 21, after the SCR device 21, before the SNCR device, after the SNCR device, and the chimney 22 outlet. During operation, by controlling the first control valve 4, the second control valve 16, and the first sampling pump 5, the switching of different sampling units can be realized, and then the flue gas at different points of the waste incineration system can be monitored online. When a point is detected, the first control valve 4 and the first sampling pump 5 in the sampling unit of the point are always in the open state, and the opening and closing of the second control valve 16 controls whether the flue gas enters the online monitor 13; when the detection of one point is completed and the next point needs to be detected, the first control valve 4, the first sampling pump 5, and the second control valve 16 in the sampling unit of the point are always in the closed state.

[0030] Furthermore, the sampling unit comprises a sampling capillary 12 , one end of which is connected to the sample delivery unit and the purge and standard gas unit through the flue gas pipeline 2 , and the other end of which is connected to the online monitor 13 .

[0031] Furthermore, the various components in the sampling unit are connected via the flue gas pipeline 2, wherein the first sampling pump 5 is installed at the front end, middle part or rear end of the flue gas pipeline.

[0032] Furthermore, the flue gas pipeline 2 is made of corrosion-resistant stainless steel, and the outside of the flue gas pipeline 2 is covered with a heat preservation member 3 , and the heat preservation temperature is 50° C. to 250° C. At least one filter sheet 7 is arranged inside the flue gas pipeline 2 .

[0033] Furthermore, the standard gas assembly includes standard gas 8 and a first mass flow meter and a control component 9, which are connected to port I of the three-way solenoid valve 11, and are used to control the opening and closing and flow of the standard gas. The standard gas 8 is one or more of monochlorobenzene, dichlorobenzene, trichlorobenzene, benzene, toluene, xylene, dichloroethylene, tetrachloroethylene and hexachlorobutadiene. When working, calibration using the standard gas assembly can further improve the detection accuracy.

[0034] Further, the purge gas assembly includes a purge gas 14 and a second mass flow meter and a control unit 15, the second mass flow meter and the control unit 15 are connected to the port I of the three-way solenoid valve 11, and the second mass flow meter and the control unit 15 are used to control the opening and closing and flow rate of the purge gas. The purge gas 14 is one or more of nitrogen, helium and air. When working, the purge gas is used to purge the gas in the sampling unit and the pipeline of the online monitor 13 to ensure the accuracy of the detection.

[0035] The waste incineration flue gas online monitoring system provided in this application can be applied to Figure 2 The waste incineration system shown includes a boiler 18, a desulfurization tower 19, a bag filter 20, an SCR device 21 and a chimney 22 connected in sequence, and a sampling point 1 can be set between the boiler 18 and the desulfurization tower 19, between the desulfurization tower 19 and the bag filter 20, between the bag filter 20 and the SCR device 21, and at the outlet of the chimney 22. The raw materials of the waste incineration system include but are not limited to industrial solid waste, hazardous waste, municipal solid waste and medical waste.

[0036] The technical solution provided in this application is further described below based on specific embodiments.

[0037] Example 1

[0038] The specific working method of the present invention for online monitoring of boiler post-incineration flue gas is as follows:

[0039] A sampling point 1 is set in the pipeline between the boiler 18 and the desulfurization tower 19;

[0040] BAccording to Figure 1 The scheme shown builds an online monitoring system;

[0041] After C is turned on, it automatically executes the purge-stabilization-collection-stabilization-calibration sequence according to the unattended execution sequence to conduct online monitoring of the post-incineration flue gas of boiler 18.

[0042] Example 2

[0043] The specific working method of the present invention for online monitoring of the post-incineration flue gas of the deacidification tower is as follows:

[0044] A sampling point 1 is set in the pipeline between the desulfurization tower 19 and the bag filter 20;

[0045] BAccording to Figure 1 The scheme shown builds an online monitoring system;

[0046] After C is turned on, it automatically executes the purge-stabilization-collection-stabilization-calibration sequence according to the unattended execution sequence to conduct online monitoring of the incineration flue gas after the deacidification tower 19.

[0047] Example 3

[0048] The specific working method of the present invention for online monitoring of the combustion flue gas at the chimney is as follows:

[0049] A. Set sampling point 1 at chimney 22;

[0050] BAccording to Figure 1 The scheme shown builds an online monitoring system;

[0051] After C is turned on, it automatically executes the purge-stabilization-collection-stabilization-calibration sequence according to the unattended execution sequence to conduct online monitoring of the post-incineration flue gas at chimney 22.

[0052] Example 4

[0053] The present invention performs online monitoring and comparative analysis on the inlet and outlet combustion flue gases of the SCR device respectively. The specific working method is as follows:

[0054] A takes sampling points 1 at the front and rear ends of the SCR device 21;

[0055] BAccording to Figure 1 The scheme shown builds an online monitoring system;

[0056] After C is turned on, the first control valve 4, the second control valve 16 and the first sampling pump 5 of the front-end sampling unit of the SCR device 21 are opened, and the purge-stabilization-collection-stabilization-calibration sequence is automatically executed according to the unattended execution sequence, and the combustion flue gas at the inlet of the SCR device is first monitored online;

[0057] After the flue gas monitoring at the D inlet is completed, the first control valve 4, the second control valve 16 and the first sampling pump 5 of the front-end sampling unit of the SCR device 21 are closed, and the first control valve 4, the second control valve 16 and the first sampling pump 5 of the rear-end sampling unit of the SCR device 21 are opened, and the purge-stabilization-collection-stabilization-calibration sequence is automatically executed according to the unattended execution sequence to perform online monitoring of the combustion flue gas at the outlet of the SCR device;

[0058] Typical spectra of the inlet and outlet flue gas of E SCR are as follows Figure 3 As shown;

[0059] The dynamic emission characteristics of F benzene series in the flue gas at the inlet and outlet of SCR over time are as follows: Figure 4 shown.

[0060] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0061] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A waste incineration flue gas online monitoring system, characterized in that: The waste incineration flue gas online monitoring system comprises a sampling unit, a purge and standard gas unit, a sampling unit and an online monitor (13), wherein: the sampling unit comprises a sampling point (1), a first control valve (4), a first sampling pump (5) and a second control valve (16) connected in sequence according to the gas flow direction, the second control valve (16) is connected to the sampling unit, and the first sampling pump (5) is also connected to the exhaust gas processor (6); the purge and standard gas unit comprises a three-way solenoid valve (11), a standard A gas component, a purge gas component, a rotor flowmeter (10) and a second sampling pump (17); the port I of the three-way solenoid valve (11) is connected to the standard gas component and the purge gas component respectively; the port II of the three-way solenoid valve (11) is connected to the rotor flowmeter (10); the port III of the three-way solenoid valve (11) is connected to the injection unit; one end of the second sampling pump (17) is connected to the rotor flowmeter (10), and the other end thereof is connected to the exhaust gas processor (6); the injection unit is connected to the online monitor (13).

2. The waste incineration flue gas online monitoring system according to claim 1, characterized in that: The waste incineration flue gas online monitoring system comprises more than two sampling units, and the access positions of the sampling points (1) in each sampling unit include after the boiler (18), after the economizer, after the deacidification tower (19), after the bag filter (20), before the SCR device (21), after the SCR device (21), before the SNCR device, after the SNCR device, and the chimney (22) outlet.

3. The waste incineration flue gas online monitoring system according to claim 1, characterized in that: The sampling unit comprises a sampling capillary (12), one end of which is connected to the sample delivery unit and the purge and standard gas unit via a flue gas pipeline (2), and the other end of which is connected to an online monitor (13).

4. The waste incineration flue gas online monitoring system according to claim 1, characterized in that: The various devices in the sampling unit are connected via a flue gas pipeline (2).

5. The waste incineration flue gas online monitoring system according to claim 3 or 4, characterized in that: The outer side of the flue gas pipeline (2) is coated with a heat-insulating component (3).

6. The waste incineration flue gas online monitoring system according to claim 3 or 4, characterized in that: At least one filter sheet (7) is arranged inside the flue gas pipeline (2).

7. The waste incineration flue gas online monitoring system according to claim 1, characterized in that: The standard gas assembly comprises standard gas (8) and a first mass flow meter and a control component (9), wherein the first mass flow meter and the control component (9) are connected to the port I of the three-way solenoid valve (11).

8. The waste incineration flue gas online monitoring system according to claim 7, characterized in that: The standard gas (8) is one or more of monochlorobenzene, dichlorobenzene, trichlorobenzene, benzene, toluene, xylene, dichloroethylene, tetrachloroethylene and hexachlorobutadiene.

9. The waste incineration flue gas online monitoring system according to claim 1, characterized in that: The purge gas assembly comprises a purge gas (14) and a second mass flow meter and a control component (15), wherein the second mass flow meter and the control component (15) are connected to the port I of the three-way solenoid valve (11).

10. The waste incineration flue gas online monitoring system according to claim 9, characterized in that: The purge gas (14) is one or more of nitrogen, helium and air.

Images