A fly ash operating resistivity online monitoring device and method

Abstract

The present invention proposes an online monitoring device and method for fly ash operating resistivity. The online monitoring device includes an air inlet elbow, a fly ash collecting bin, a driving mechanism, a backflush system, a sampling gun, an induced draft fan, a high resistance tester and a temperature and humidity tester. A plurality of movable electrodes are arranged in the fly ash collecting bin. The driving mechanism is used to drive the electrodes in the fly ash collecting bin to switch positions. The first air inlet end, the first air outlet end, the second air inlet end and the second air outlet end of the fly ash collecting bin are respectively connected to the air inlet elbow, the sampling gun, the backflush system and a cleaning box. The outlet of the sampling gun is connected to the induced draft fan. The high resistance tester and the temperature and humidity tester are both connected to the sampling gun and are used to measure the operating resistivity of the fly ash and the temperature and humidity of the flue gas, respectively, thereby realizing online monitoring of the operating resistivity. The switching positions of the electrodes in the fly ash collecting bin are controlled by the driving mechanism, so that multiple electrodes can be switched for use.

Description

[Technical field]

[0001] The invention relates to the technical field of flue gas monitoring devices, and in particular to an online monitoring device and method for fly ash operating condition specific resistance. [Background technology]

[0002] Flue gas treatment systems are used to treat industrial waste gas and are widely used in thermal power generation and chemical industries. In flue gas treatment systems, the operating resistivity and experimental resistivity of fly ash are often measured. The operating resistivity refers to the resistivity measured when the flue gas treatment system is operating normally, while the experimental resistivity is the resistivity obtained by measuring the sampled flue gas. Both resistivity are of reference value, so that technicians can formulate reasonable flue gas treatment processes. Current fly ash operating resistivity monitoring devices mostly adopt on-site sampling and laboratory measurement to obtain the operating resistivity. Not only can the operating resistivity not be accurately measured, but it is also impossible to achieve online measurement. Here, an online monitoring device and method for fly ash operating resistivity are proposed. [Summary of the invention]

[0003] The purpose of the present invention is to solve the problems in the prior art and to provide an online monitoring device and method for fly ash operating resistivity, which can realize online real-time measurement of operating resistivity.

[0004] To achieve the above-mentioned purpose, the present invention proposes an online monitoring device for fly ash operating resistivity, comprising an air inlet elbow, a fly ash collecting bin, a driving mechanism, a back-blowing system, a sampling gun, an induced draft fan, a high resistance tester and a temperature and humidity tester. At least two movable electrodes are arranged in the fly ash collecting bin. The driving mechanism is transmission-connected to the fly ash collecting bin and is used to drive the electrodes in the fly ash collecting bin to switch positions. The first air inlet end of the fly ash collecting bin is connected to the outlet of the air inlet elbow, the first air outlet end of the fly ash collecting bin is connected to the inlet of the sampling gun, the outlet of the sampling gun is connected to the induced draft fan, the high resistance tester and the temperature and humidity tester are both connected to the sampling gun and are used to measure the fly ash operating resistivity and the temperature and humidity of the flue gas, respectively. The second air inlet end of the fly ash collecting bin is connected to the outlet of the back-blowing system, and the second air outlet end of the fly ash collecting bin is connected to the inlet of a cleaning box. When one electrode in the fly ash collecting bin is switched to be connected to the air inlet elbow and the sampling gun, at least one of the remaining electrodes is connected to the back-blowing system and the cleaning box.

[0005] Preferably, the driving mechanism controls the switching position of each electrode by driving the fly ash collection bin to translate or rotate.

[0006] Preferably, two electrodes are arranged in the fly ash collection bin, namely a first electrode and a second electrode. The driving mechanism is transmission-connected to the fly ash collection bin and is used to drive the first electrode and the second electrode to switch positions. When one of the first electrode and the second electrode is connected to the air intake elbow and the sampling gun, the other is connected to the backflush system and the cleaning box.

[0007] Preferably, the fly ash collection bin further comprises an outer shell and an insulating installation body, wherein the insulating installation body is arranged in the inner cavity of the outer shell, and a plurality of chambers for installing electrodes are provided in the insulating installation body.

[0008] Preferably, the insulating mounting body is provided with a plurality of circumferentially distributed chambers, the driving mechanism comprises a motor and a rotating shaft, one end of the rotating shaft is mounted at the axis center of the insulating mounting body, and the other end is transmission-connected to the motor.

[0009] Preferably, the electrodes include a positive electrode and a negative electrode, and insulating polytetrafluoroethylene is disposed at the top of the negative electrode, the bottom of the positive electrode, and between the walls of the positive electrode and the negative electrode.

[0010] Preferably, the negative electrode of the electrode is a mesh structure with a built-in ceramic filter.

[0011] Preferably, the air inlet elbow is gooseneck-shaped, and the inlet end of the air inlet elbow has a streamlined sampling nozzle.

[0012] Preferably, the back-blowing system is provided with a blower, and the air outlet of the blower is connected to the second air inlet end of the fly ash collection bin.

[0013] The present invention also proposes an online monitoring method for fly ash operating resistivity and a calculation method for fly ash operating resistivity, which specifically include the following steps:

[0014] S1. Use the following algorithm to calculate the volume resistivity and surface resistivity of fly ash:

[0015] ρ v =exp(-1.8916ln X-0.9696ln Y+1.237ln Z+3.62876-0.069078E+9980.58 / T) (1)

[0016] ρ s =exp[27.59774-2.233348lnX-0.00176W-0.069078E-0.00073895Wexp(2303.3 / T)] (2)

[0017] In the formula, ρ v , sare the volume resistivity and surface resistivity of fly ash respectively; X, Y, and Z are the atomic mass fractions of Li+Na, Fe, and Mg+Ca respectively; E is the electric field intensity; T is the temperature; and W is the water vapor content.

[0018] S2. When Z>3.5% or K<1.0%, where K is the atomic mass fraction of potassium, the total specific resistance is calculated as:

[0019]

[0020] S3. Operating resistivity When considering the influence of sulfuric acid mist deposited on the fly ash surface on its resistivity, the correction amount is expressed by the following formula:

[0021]

[0022] At this time, the working condition specific resistance calculation formula is:

[0023]

[0024] Beneficial effects of the present invention: The present invention realizes online monitoring of the working condition specific resistance by cooperating with the air intake elbow, fly ash collection bin, driving mechanism, back-blowing system, sampling gun, induced draft fan, high resistance tester and temperature and humidity tester, etc. The high resistance tester is used to measure the working condition specific resistance of fly ash, and the temperature and humidity tester is used to measure and record the temperature and humidity of flue gas. After the test is completed, the driving mechanism can be used to control the switching position of each electrode in the fly ash collection bin, so that the electrode filled with fly ash is switched to the state connected with the back-blowing system, and the back-blowing system is used to clean it and put it aside, thereby realizing the switching use of multiple electrodes.

[0025] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0026] Figure 1 It is a structural schematic diagram of an online monitoring device for fly ash operating resistivity according to the present invention;

[0027] Figure 2 It is a side view of the internal structure of a fly ash collection bin of an online monitoring device for fly ash operating resistivity according to the present invention. [Specific implementation method]

[0028] See also Figure 1 to Figure 2The present invention discloses an online monitoring device for fly ash working condition specific resistance, comprising an air intake elbow 1, a fly ash collecting bin 2, a driving mechanism 3, a backflush system 4, a sampling gun 5, an induced draft fan 6, a high resistance tester 7 and a temperature and humidity tester 8. At least two movable electrodes 20 are arranged in the fly ash collecting bin 2. The driving mechanism 3 is transmission-connected to the fly ash collecting bin 2 and is used to drive each electrode 20 in the fly ash collecting bin 2 to switch positions. The first air intake end of the fly ash collecting bin 2 is connected to the outlet of the air intake elbow 1, and the first air outlet end of the fly ash collecting bin 2 is connected to the sampling The inlet of the sampling gun 5, the outlet of the sampling gun 5 is connected to the induced draft fan 6, the high resistance tester 7 and the temperature and humidity tester 8 are connected to the sampling gun 5, and are respectively used to measure the fly ash working resistivity and the temperature and humidity of the flue gas. The second air inlet end of the fly ash collecting bin 2 is connected to the outlet of the backflush system 4, and the second air outlet end of the fly ash collecting bin 2 is connected to the inlet of the cleaning box. When one electrode 20 in the fly ash collecting bin 2 is switched to be connected with the air inlet elbow 1 and the sampling gun 5, at least one of the remaining electrodes 20 is connected with the backflush system 4 and the cleaning box.

[0029] Furthermore, the driving mechanism 3 controls the switching position of each electrode 20 by driving the fly ash collection bin 2 to translate or rotate.

[0030] Furthermore, two electrodes 20 are arranged in the fly ash collection bin 2, namely the first electrode and the second electrode. The driving mechanism 3 is in transmission connection with the fly ash collection bin 2, and is used to drive the first electrode and the second electrode to switch positions. When one of the first electrode and the second electrode is connected to the air intake elbow 1 and the sampling gun 5, the other is connected to the backflush system 4 and the cleaning box. The fly ash collection bin 2 also includes an outer shell 21 and an insulating mounting body 22. The insulating mounting body 22 is arranged in the inner cavity of the outer shell 21, and a plurality of chambers for mounting the electrodes 20 are arranged in the insulating mounting body 22.

[0031] Furthermore, in this embodiment, the insulating mounting body 22 is provided with a plurality of circumferentially distributed chambers, the driving mechanism 3 includes a motor 31 and a rotating shaft 32, one end of the rotating shaft 32 is installed at the axis of the insulating mounting body 22, and the other end is connected to the motor 31. The two electrodes are connected and used in turn, and are switched back and forth through the intermediate rotating shaft 32; the electrode 20 includes a positive electrode 201 and a negative electrode 202, and insulating polytetrafluoroethylene is provided at the top of the negative electrode 202, the bottom of the positive electrode 201, and the wall surfaces of the positive electrode 201 and the negative electrode 202.

[0032] Furthermore, the negative electrode of the electrode 20 is a mesh structure and has a built-in ceramic filter element 200. The ceramic filter element mainly plays a filtering role, retaining fly ash particles in the electrode slot, allowing airflow to pass smoothly.

[0033] Furthermore, the air inlet elbow 1 is gooseneck-shaped, and the inlet end of the air inlet elbow 1 has a streamlined sampling nozzle to ensure that the fly ash particles enter at a uniform speed with the airflow during isokinetic sampling, and the particle size distribution is uniform and consistent with that in the flue.

[0034] Furthermore, the back-blowing system 4 is provided with a blower, and the air blowing port of the blower is connected to the second air inlet end of the fly ash collecting bin 2 .

[0035] The present invention provides an online monitoring device for fly ash operating resistivity. During use, the motor 31 controls the switching of the first electrode and the second electrode. The switching time is signaled by the filling of the fly ash in the electrode slot, that is, when the pressure of the induced draft fan 6 reaches the set resistance value, the air extraction is stopped, and the high resistance tester 7 (shell grounded) is started to measure the fly ash operating resistivity, and the temperature and humidity of the flue gas at this time are measured and recorded by the temperature and humidity tester 8, and automatically stored; after the test is completed and stored, the motor 31 is started to switch the electrode 20, and the next sampling measurement is carried out. The electrode 20 that has completed the measurement and is filled with fly ash is switched to a state connected to the backflush system 4, and is cleaned by opening the backflush system 4 and then put into use.

[0036] The system is equipped with an automatic working condition specific resistance verification system. The working condition specific resistance calculation formula is as follows. The calculation result and the measured value are simultaneously presented on the electrostatic precipitator host computer for reference by the commissioning personnel. The present invention also proposes a method for calculating the working condition specific resistance of fly ash, which specifically includes the following steps:

[0037] S1. Use the following algorithm to calculate the volume resistivity and surface resistivity of fly ash:

[0038] ρ v =exp(-1.8916ln X-0.9696ln Y+1.237ln Z+3.62876-0.069078E+9980.58 / T) (1)

[0039] ρ s =exp[27.59774-2.233348lnX-0.00176W-0.069078E-0.00073895Wexp(2303.3 / T)] (2)

[0040] In the formula, ρ v , s are the volume resistivity and surface resistivity of fly ash (Ω·cm), respectively; X, Y, and Z are the atomic mass fractions (%) of Li+Na, Fe, and Mg+Ca, respectively; E is the electric field intensity (kV / cm); T is the temperature (K); and W is the water vapor content (%).

[0041] S2. When Z>3.5% or K<1.0%, where K is the atomic mass fraction of potassium, the total specific resistance is calculated as:

[0042]

[0043] S3. When the operating resistivity needs to consider the influence of sulfuric acid mist deposited on the fly ash surface on its resistivity, the correction amount can be expressed by the following formula:

[0044]

[0045] Among them, C SO3 Indicates the sulfur trioxide concentration in flue gas (ppm),

[0046] At this time, the working condition specific resistance calculation formula is:

[0047]

[0048] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. An online monitoring device for fly ash specific resistivity under working conditions, characterized in that: The invention comprises an air intake elbow (1), a fly ash collection bin (2), a driving mechanism (3), a backflush system (4), a sampling gun (5), an induced draft fan (6), a high resistance tester (7) and a temperature and humidity tester (8); at least two movable electrodes (20) are arranged in the fly ash collection bin (2); the driving mechanism (3) is transmission-connected to the fly ash collection bin (2) and is used to drive each electrode (20) in the fly ash collection bin (2) to switch positions; a first air intake end of the fly ash collection bin (2) is connected to the outlet of the air intake elbow (1); a first air outlet end of the fly ash collection bin (2) is connected to the inlet of the sampling gun (5); the outlet of the sampling gun (5) is connected to the induced draft fan (6); the high resistance tester (7) and the temperature and humidity tester (8) are both connected to the sampling gun (5) and are used to measure the fly ash working condition specific resistance and the flue gas humidity, respectively. temperature and humidity, the second air inlet end of the fly ash collection bin (2) is connected to the outlet of the backflush system (4), the second air outlet end of the fly ash collection bin (2) is connected to the inlet of the cleaning box, when one electrode (20) in the fly ash collection bin (2) is switched to be connected to the air inlet elbow (1) and the sampling gun (5), at least one of the remaining electrodes (20) is connected to the backflush system (4) and the cleaning box; two electrodes (20) are arranged in the fly ash collection bin (2), namely a first electrode and a second electrode; the driving mechanism (3) is transmission-connected to the fly ash collection bin (2) and is used to drive the first electrode and the second electrode to switch positions; when one of the first electrode and the second electrode is connected to the air inlet elbow (1) and the sampling gun (5), the other is connected to the backflush system (4) and the cleaning box; the calculation steps of the fly ash working condition specific resistance are as follows: S1. Calculate the volume resistivity and surface resistivity of fly ash using the following algorithm: (1)； (2)； In the formula, ρ v , s are the volume resistivity and surface resistivity of fly ash respectively; X, Y, and Z are the atomic mass fractions of Li+Na, Fe, and Mg+Ca respectively; E is the electric field intensity; T is the temperature; and W is the water vapor content; S2. When Z>3.5% or K<1.0%, where K is the atomic mass fraction of potassium, the total specific resistance is calculated as: (3)； S3. Operating resistivity When considering the effect of sulfuric acid mist deposited on the fly ash surface on its resistivity, the correction amount is expressed by the following formula: (4)； in, C SO3 Indicates the sulfur trioxide concentration in flue gas. At this time, the working condition specific resistance calculation formula is: (5)。 2. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The driving mechanism (3) controls the switching position of each electrode (20) by driving the fly ash collection bin (2) to translate or rotate.

3. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The fly ash collection bin (2) further comprises an outer shell (21) and an insulating installation body (22); the insulating installation body (22) is arranged in the inner cavity of the outer shell (21); and a plurality of chambers for installing electrodes (20) are arranged in the insulating installation body (22).

4. The fly ash operating resistivity online monitoring device according to claim 3, characterized in that: The insulating mounting body (22) is provided with a plurality of circumferentially distributed chambers, and the driving mechanism (3) comprises a motor (31) and a rotating shaft (32), wherein one end of the rotating shaft (32) is mounted at the axis of the insulating mounting body (22), and the other end is drivingly connected to the motor (31).

5. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The electrode (20) comprises a positive electrode (201) and a negative electrode (202), and insulating polytetrafluoroethylene is provided at the top end of the negative electrode (202), the bottom end of the positive electrode (201), and between the walls of the positive electrode (201) and the negative electrode (202).

6. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The negative electrode of the electrode (20) is a mesh structure and has a built-in ceramic filter element (200).

7. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The air inlet elbow (1) is in the shape of a gooseneck, and the inlet end of the air inlet elbow (1) is provided with a streamlined sampling nozzle.

8. The fly ash operating resistivity online monitoring device according to claim 1, characterized in that: The back-blowing system (4) is provided with a blower, and the air outlet of the blower is connected to the second air inlet end of the fly ash collection bin (2).

Images