Liquid drop sampling system of wet desulphurization demister and slurry drop content calculation method

Abstract

The invention relates to the technical field of wet desulphurization, in particular to a wet desulphurization demister liquid drop sampling system and a slurry drop content calculation method.The wet desulphurization demister liquid drop sampling system comprises a flue gas and dust instrument and a liquid drop catcher, and the liquid drop catcher comprises a shell; the interior of the shell is divided into a first cavity for arranging a trapezoidal folding pipe and a second cavity for arranging a coiled pipe and a filter screen, an inlet of the trapezoidal folding pipe is communicated with a sampling nozzle arranged on the outer surface of the first cavity, and an outlet of the trapezoidal folding pipe is communicated with an inlet of the coiled pipe; the filter screen is arranged on the rear side of the outlet of the coiled pipe, and the outlet end of the second cavity is detachably installed on the smoke and dust instrument. By applying the wet desulphurization demister droplet sampling system and the slurry droplet content calculation method, accurate sampling of droplets can be realized in practical application, and the slurry droplet content in flue gas can be further accurately calculated.

Description

Technical Field

[0001] The invention relates to the technical field of wet desulfurization, and in particular to a wet desulfurization demister droplet sampling system and a slurry droplet content calculation method. Background Art

[0002] Limestone-gypsum wet desulfurization technology is the most mature, reliable and widely used desulfurization technology among existing desulfurization technologies, accounting for more than 85% of coal-fired power plants. However, due to the low temperature of the net flue gas at the outlet of the demister after desulfurization, the temperature of the flue gas is further reduced after it is discharged into the atmosphere, and the gaseous water condenses into small droplets of liquid saturated water and falls. The small droplets contain gypsum slurry and solid particles, which will form gypsum rain. Gypsum rain is not only corrosive to the flue and chimney, but also pollutes the environment.

[0003] Therefore, there is an urgent need for a wet flue gas desulfurization demister droplet sampling system and a slurry droplet content calculation method to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the problem in the prior art that the exhaust of flue gas from the outlet of a wet desulfurization demister will form corrosive gypsum rain, and to provide a wet desulfurization demister droplet sampling system and a slurry droplet content calculation method.

[0005] In order to achieve the above-mentioned objectives, the first aspect of the present invention provides a wet flue gas and dust meter droplet sampling system, which includes a flue gas and dust meter and a droplet collector. The droplet collector includes a shell, the interior of the shell is divided into a first cavity for arranging a trapezoidal folded tube and a second cavity for arranging a serpentine tube and a filter. The inlet of the trapezoidal folded tube is connected to a sampling nozzle arranged on the outer surface of the first cavity, and the outlet is connected to the inlet of the serpentine tube. The filter is arranged on the rear side of the serpentine tube outlet, and the outlet end of the second cavity is detachably mounted on the flue gas and dust meter.

[0006] Preferably, the diameter of the trapezoidal folded tube is 8-16 mm and the bending angle is 35-60°, the diameter of the serpentine tube is 4-8 mm, and the droplet filtration accuracy of the filter is 15-25 μm.

[0007] Preferably, a filter membrane is provided at the air-facing end of the filter screen; the sampling nozzle comprises a nozzle and a tube body connected to the nozzle, the diameter of the nozzle is 4-20 mm, and the diameter of the tube body is 6-10 mm.

[0008] Preferably, the flue gas and dust instrument comprises a sampling smoke gun and an analysis and measurement device, and the outlet end of the second cavity is detachably mounted on a droplet collector mounting tube of the sampling smoke gun.

[0009] Preferably, the droplet catcher is made of stainless steel or titanium alloy.

[0010] The second aspect of the present invention provides a method for calculating the droplet content of a slurry in a wet desulfurization mist eliminator, which is applied to the droplet sampling system described above. The method for calculating the droplet content of the slurry comprises the following steps:

[0011] S1. Determine the specifications of the sampling nozzle of the droplet collector according to the flow rate of the flue gas in the flue duct at the outlet of the demister;

[0012] S2, installing the droplet collector on the droplet collector mounting tube of the sampling gun of the flue gas and smoke instrument;

[0013] S3, using the analysis and measurement device of the flue gas and dust meter to perform parallel automatic sampling, and keeping the suction speed of the sampling nozzle equal to the air flow speed at the measurement point during the sampling process, and at the same time turning on the heating device of the sampling smoke gun to keep the temperature of the droplet collector and the sampling tube of the sampling smoke gun at 100-120° C.;

[0014] S4. After the flue gas sampling is completed, the droplet catcher is removed, and the inside of the droplet catcher is rinsed with deionized water in a laboratory environment. The washing liquid is collected in a volumetric flask, and concentrated nitric acid is added to acidify it, and the volume is fixed to the mark with deionized water to obtain the magnesium ion concentration C1 of the droplet catcher absorption solution; at the same time, the magnesium ion concentration C2 of the slurry liquid phase of the desulfurization absorption tower is collected;

[0015] S5. Calculate the slurry droplet content in the flue gas based on the obtained magnesium ion concentration C1 of the droplet collector absorption solution and the magnesium ion concentration C2 of the slurry liquid phase in the desulfurization absorption tower.

[0016] Preferably, the slurry droplet content C in the flue gas is yd The calculation formula is:

[0017]

[0018] Among them, C yd is the slurry droplet content in the flue gas, mg / m 3 ; C1 is the magnesium ion concentration of the droplet collector absorption solution, mg / L; V d is the fixed volume of the droplet collector absorption solution, mL; C2 is the magnesium ion concentration of the absorption tower slurry liquid phase, mg / L; V g is the volume of flue gas (standard, dry), m 3 ; C x is the solid content of the absorber slurry expressed as mass fraction, %.

[0019] Preferably, the solid content C of the absorber slurry expressed as mass fraction is x The calculation formula is:

[0020]

[0021] Among them, C s is the solid content of slurry, g / L; ρ t is the density of the slurry at temperature t℃, kg / L.

[0022] Preferably, the slurry solid content C s The calculation formula is:

[0023]

[0024] Where ρ1 is the density of the aqueous solution in the slurry at temperature t℃, kg / L; ρ s is the true density of slurry solid matter, kg / L.

[0025] Preferably, in step S1, the formula for determining the specifications of the sampling nozzle of the droplet collector according to the flow rate of the flue gas in the flue duct at the outlet of the demister includes:

[0026]

[0027] Where, d is the diameter of the sampling nozzle, mm; Q' r is the rotor flowmeter reading of the constant speed sampling flow, L / min; V s is the gas velocity at the measuring point, m / s; B a is atmospheric pressure, Pa; P s is the exhaust static pressure, Pa; P r is the gas pressure before the rotor flowmeter, Pa; t s is the exhaust temperature, °C; t r is the gas temperature before the rotor flowmeter, ℃; X sw is the volume percentage of moisture content in the exhaust gas, %.

[0028] Preferably, before step S2, the method further includes: soaking and cleaning the droplet collector with potassium dichromate solution, then rinsing it with deionized water, drying it at 100-110° C. for 1-3 hours, and finally installing it after cooling it to room temperature.

[0029] According to the above technical scheme, based on the wet flue gas desulfurization demister droplet sampling system and the slurry droplet content calculation method, in actual application, by designing a droplet collector for use with the flue gas and dust meter, the collected demister outlet flue gas can be freely colliding under the action of the trapezoidal folding tube and the serpentine tube, and the droplets can be intercepted under the action of the filter, thereby achieving accurate capture of the target droplets in the flue gas, and further by measuring the slurry droplet content in the collected target droplets, it is possible to accurately judge whether the demister outlet flue gas will cause gypsum rain based on the measured slurry droplet content, and timely take corresponding treatment measures when the slurry droplet content exceeds the emission standard and will cause gypsum rain. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the droplet sampling system of the wet desulfurization demister;

[0031] Figure 2 It is a schematic diagram of the structure of the droplet collector of the droplet sampling system of the wet desulfurization demister;

[0032] Figure 3 It is a flow chart of the method for calculating the slurry droplet content of the wet desulfurization demister.

[0033] Description of Reference Numerals

[0034] 1. Flue; 2. Pitot tube; 3. Droplet collector; 31. Shell; 32. Sampling nozzle; 33. Trapezoidal folding tube; 34. Serpentine tube; 35. Filter; 4. Droplet collector mounting tube; 5. Heating device; 6. Sampling tube; 7. Smoke gun control device; 8. Analytical and measuring device. DETAILED DESCRIPTION

[0035] The specific implementation of the embodiment of the present invention is described in detail below. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0036] The first aspect of the present invention provides a wet desulfurization mist eliminator droplet sampling system, such as Figure 1-2 As shown, the wet flue gas desulfurization mist demister droplet sampling system includes a flue gas and dust meter and a droplet collector 3, the droplet collector 3 includes a shell 31, the interior of the shell 31 is divided into a first cavity for arranging a trapezoidal folded tube 33 and a second cavity for arranging a serpentine tube 34 and a filter 35, the inlet of the trapezoidal folded tube 33 is connected to a sampling nozzle 32 arranged on the outer surface of the first cavity, and the outlet is connected to the inlet of the serpentine tube 34, the filter 35 is arranged on the rear side of the outlet of the serpentine tube 34, and the outlet end of the second cavity is detachably mounted on the flue gas and dust meter.

[0037] According to the above technical scheme, based on the wet desulfurization demister droplet sampling system, in the actual application process, by designing a droplet collector for use with the flue gas and dust meter, the collected demister outlet flue gas can be freely colliding under the action of the trapezoidal folding tube and the serpentine tube, and the droplets can be intercepted under the action of the filter, thereby achieving accurate capture of the target droplets in the flue gas, and further by measuring the slurry droplet content in the collected target droplets, it is possible to accurately judge whether the demister outlet flue gas will cause gypsum rain based on the measured slurry droplet content, and timely collect corresponding treatment measures when the slurry droplet content exceeds the emission standard and will cause gypsum rain.

[0038] In the wet desulfurization demister droplet sampling system of the present invention, preferably, as Figure 2 As shown, the diameter of the trapezoidal folded tube 33 is 8-16mm and the bending angle is 35-60°. Specifically, the bending angle of the trapezoidal folded tube 33 is preferably 40-50°, and most preferably 45°. The diameter of the serpentine tube 34 is 4-8mm, preferably 5-7mm, and most preferably 6mm. The droplet filtration accuracy of the filter 35 is 15-25μm, preferably 18-22μm, and most preferably 20μm, thereby further improving the capture accuracy of the target droplets in the flue gas based on free impact. In another preferred embodiment, a filter membrane is provided at the air-facing end of the filter 35, so as to better intercept and capture the target droplets, prevent the target droplets from escaping and affecting the collection accuracy.

[0039] In the wet flue gas desulfurization mist eliminator droplet sampling system described in the present invention, preferably, the sampling nozzle 32 includes a nozzle and a tube body connected to the nozzle, the diameter of the nozzle is 4-20mm, and the diameter of the tube body is 6-10mm, so as to effectively avoid the turbulence of the airflow near the sampling nozzle and better realize isokinetic sampling. In a specific embodiment, the diameter of the tube body of the sampling nozzle 32 is preferably fixed to 8mm, so its different specifications here are determined by the diameter of its nozzle. Specifically, the diameter of the nozzle can be 4mm, 5mm, 6mm, 8mm, 10mm and 12mm, etc., so as to select the sampling nozzle 32 with a nozzle of appropriate diameter for sampling according to the predicted flow rate, thereby saving time and improving the accuracy and efficiency of isokinetic sampling.

[0040] In the wet flue gas desulfurization mist demister droplet sampling system described in the present invention, preferably, the flue gas and smoke meter includes a sampling smoke gun and an analysis and measurement device 8, and the outlet end of the second cavity is detachably mounted on the droplet catcher mounting tube 4 of the sampling smoke gun, so that the accurate capture of target droplets can be achieved by using the flue gas and smoke meter and the droplet catcher 3 in combination. In a specific embodiment, the sampling smoke gun includes a Pitot tube 2, a droplet catcher mounting tube 4, a heating device 5, a sampling tube 6 and a smoke gun control device 7, and the smoke gun control device 7 is connected to the analysis and measurement device 8, so that in actual application, when the flue gas and smoke meter and the droplet catcher 3 are used as Figure 1 After the installation is completed, the sampling nozzle 31 can be used to suck in flue gas for automatic sampling through the analysis and measurement device 8. The flue gas and dust meter is a direct application of the prior art, and the improvement here is that a droplet catcher mounting tube 4 is designed for detachably mounting the droplet catcher 3, so it will not be described in detail. In a more specific embodiment, the droplet catcher 3 and the droplet catcher mounting tube 4 are connected by threads, that is, matching threads are set at the outlet end of the second cavity and the screw-in end of the droplet catcher mounting tube 4.

[0041] In the wet flue gas desulfurization demister droplet sampling system of the present invention, preferably, the droplet collector 3 is made of stainless steel or titanium alloy, so as to be better suitable for the needs of on-site sampling and has the advantages of being resistant to high temperatures, not easy to break and easy to clean.

[0042] The second aspect of the present invention provides a method for calculating the droplet content of a wet desulfurization mist eliminator slurry, which is applied to the droplet sampling system described above. Figure 3 As shown, the slurry droplet content calculation method includes the following steps:

[0043] S1. Determine the specification of the sampling nozzle 32 of the droplet collector 3 according to the flow rate of the flue gas in the flue gas duct at the demister outlet;

[0044] S2, installing the droplet collector 3 on the droplet collector mounting tube 4 of the sampling gun of the flue gas and smoke instrument;

[0045] S3, using the analysis and measurement device 8 of the flue gas and dust meter to perform parallel automatic sampling, and keeping the suction speed of the sampling nozzle 32 equal to the air flow speed at the measuring point during the sampling process, and at the same time turning on the heating device 5 of the sampling smoke gun to keep the temperature of the droplet catcher 3 and the sampling tube 6 of the sampling smoke gun at 100-120° C. Specifically, by keeping the temperature of the droplet catcher 3 and the sampling tube 6 of the sampling smoke gun at 100-120° C., it is possible to effectively avoid the non-target droplets in the flue gas from condensing after being cooled, thereby affecting the sampling accuracy of the target droplets;

[0046] S4. After the flue gas sampling is completed, the droplet catcher 3 is removed, and the inside of the droplet catcher 3 is rinsed with deionized water in a laboratory environment. The washing liquid is collected in a volumetric flask, and concentrated nitric acid is added to acidify it, and the volume is fixed to the mark with deionized water to obtain the magnesium ion concentration C1 of the droplet catcher absorption solution; at the same time, the magnesium ion concentration C2 of the slurry liquid phase of the desulfurization absorption tower is collected;

[0047] S5. Calculate the slurry droplet content in the flue gas based on the obtained magnesium ion concentration C1 of the droplet collector absorption solution and the magnesium ion concentration C2 of the slurry liquid phase in the desulfurization absorption tower.

[0048] According to the above technical scheme, based on the slurry droplet content calculation method, in the actual application process, by designing a droplet collector for use with the flue gas and dust meter, the collected flue gas at the demister outlet can be freely colliding under the action of the trapezoidal folding tube and the serpentine tube, and the droplets can be intercepted under the action of the filter, thereby achieving accurate capture of the target droplets in the flue gas, and further by measuring the slurry droplet content in the collected target droplets, it is possible to accurately judge whether the demister outlet flue gas will cause gypsum rain based on the measured slurry droplet content, and timely take corresponding treatment measures when the slurry droplet content exceeds the emission standard and will cause gypsum rain.

[0049] In the method for calculating the slurry droplet content of the wet desulfurization demister of the present invention, preferably, the slurry droplet content C in the flue gas is yd The calculation formula is:

[0050]

[0051] Among them, C yd is the slurry droplet content in the flue gas, mg / m 3 ; C1 is the magnesium ion concentration of the droplet collector absorption solution, mg / L; V d is the fixed volume of the droplet collector absorption solution, mL; C2 is the magnesium ion concentration of the absorption tower slurry liquid phase, mg / L; V g is the volume of flue gas (standard, dry), m 3 ; C x is the solid content of the absorber slurry expressed as mass fraction, %. Where, V g Directly acquired by the analytical measuring device 8;

[0052] Further preferably, the solid content C of the absorption tower slurry expressed in mass fraction is x The calculation formula is:

[0053]

[0054] Among them, C s is the solid content of slurry, g / L; ρ tis the density of the slurry at temperature t℃, kg / L.

[0055] Further preferably, the slurry solid content C s The calculation formula is:

[0056]

[0057] Where ρ1 is the density of the aqueous solution in the slurry at temperature t℃, kg / L; ρ s is the true density of slurry solid matter, kg / L.

[0058] Specifically, in practical applications, the slurry drop content in the flue gas can be accurately calculated based on the above formula, so that it can be accurately determined whether the flue gas at the demister outlet will cause gypsum rain based on the calculated slurry drop content, and then the corresponding treatment measures can be taken in time when the slurry drop content exceeds the emission standard and causes gypsum rain. Specifically, for example, the demister can be replaced or modified.

[0059] In the method for calculating the droplet content of the wet desulfurization demister slurry of the present invention, preferably, in step S1, the formula for determining the specifications of the sampling nozzle 32 of the droplet collector 3 according to the flow rate of the flue gas in the demister outlet flue includes:

[0060]

[0061] Where, d is the diameter of the sampling nozzle, mm; Q' r is the rotor flowmeter reading of the constant speed sampling flow, L / min; V s is the gas velocity at the measuring point, m / s; B a is atmospheric pressure, Pa; P s is the exhaust static pressure, Pa; P r is the gas pressure before the rotor flowmeter, Pa; t s is the exhaust temperature, °C; t r is the gas temperature before the rotor flowmeter, ℃; X sw is the volume percentage of moisture content in the exhaust gas, %.

[0062] Specifically, it can be seen from the above formula that: when a sampling nozzle with a small diameter nozzle is selected, the sampling flow rate will be reduced, the relative error of the flow reading will increase, and the volume of flue gas collected per unit time will be smaller, and sufficient samples cannot be obtained; at the same time, if the diameter of the sampling nozzle is too small, larger particles will be excluded, thereby causing system errors; when a sampling nozzle with a large diameter nozzle is selected, the sampling flow rate will inevitably increase, which may cause the required flow rate to not be achieved due to the load limitation of the instrument sampling power; therefore, in actual applications, it is necessary to select a sampling nozzle with a suitable diameter nozzle to improve the accuracy of droplet capture.

[0063] In the method for calculating the droplet content of the wet desulfurization mist eliminator of the present invention, preferably, before step S2, it also includes: soaking and cleaning the droplet collector 3 with potassium dichromate washing solution, then rinsing it with deionized water, drying it at 100-110°C for 1-3h, and finally installing it after cooling to room temperature, so as to improve the sampling accuracy of the target droplets in the flue gas. In another preferred embodiment, before step S3, it also includes: checking the air tightness of the entire droplet sampling system to avoid unqualified air tightness and affecting the sampling accuracy of the target droplets.

[0064] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0065] Example 1

[0066] Use Figure 1-2 The wet flue gas desulfurization mist eliminator droplet sampling system shown is implemented, specifically, the wet flue gas desulfurization mist eliminator droplet sampling system includes a flue gas dust meter and a droplet collector 3, the droplet collector 3 includes a shell 31, the interior of the shell 31 is divided into a first cavity for arranging a trapezoidal folded tube 33 and a second cavity for arranging a serpentine tube 34 and a filter 35, the inlet of the trapezoidal folded tube 33 is connected to a sampling nozzle 32 arranged on the outer surface of the first cavity, and the outlet is connected to the inlet of the serpentine tube 34, the filter 35 is arranged at the rear side of the outlet of the serpentine tube 34, and the outlet end of the second cavity is detachably mounted on the flue gas dust meter;

[0067] The diameter of the trapezoidal folded tube 33 is 10 mm, the diameter of the serpentine tube 34 is 6 mm, and the droplet filtration accuracy of the filter 35 is 20 μm; the flue gas and smoke meter includes a sampling smoke gun and an analysis and measurement device 8, and the outlet end of the second cavity can be detachably mounted on the droplet collector mounting tube 4 of the sampling smoke gun; the droplet collector 3 is made of stainless steel.

[0068] In practical application, S1, the specification of the sampling nozzle 32 of the droplet collector 3 is determined according to the flow rate of the flue gas in the flue gas duct at the outlet of the demister;

[0069] S2, installing the droplet collector 3 on the droplet collector mounting tube 4 of the sampling gun of the flue gas and smoke instrument, and Figure 1 Settings shown;

[0070] S3, using the analysis and measurement device 8 of the flue gas and dust instrument to perform parallel automatic sampling, and keeping the suction speed of the sampling nozzle 32 equal to the air flow speed at the measuring point during the sampling process, and at the same time turning on the heating device 5 of the sampling smoke gun to keep the temperature of the droplet collector 3 and the sampling tube 6 of the sampling smoke gun at 110° C.;

[0071] S4. After the flue gas sampling is completed, the droplet catcher 3 is removed, and the inside of the droplet catcher 3 is rinsed with deionized water in a laboratory environment. The washing liquid is collected in a 100 ml volumetric flask, 1 ml of concentrated nitric acid is added to acidify, and the volume is fixed to the mark with deionized water to obtain the droplet catcher absorption solution magnesium ion concentration C1; at the same time, the desulfurization absorption tower slurry liquid phase magnesium ion concentration C2 is collected;

[0072] S5. Calculate the slurry droplet content in the flue gas based on the obtained magnesium ion concentration C1 of the droplet collector absorption solution and the magnesium ion concentration C2 of the slurry liquid phase in the desulfurization absorption tower;

[0073] Slurry droplet content in flue gas C yd The calculation formula is:

[0074]

[0075] Among them, C yd is the slurry droplet content in the flue gas, mg / m 3 ; C1 is the magnesium ion concentration of the droplet collector absorption solution, mg / L; V d is the fixed volume of the droplet collector absorption solution, mL; C2 is the magnesium ion concentration of the absorption tower slurry liquid phase, mg / L; V g is the volume of flue gas (standard, dry), m 3 ; C x is the solid content of the absorber slurry expressed as mass fraction, %;

[0076] Absorber slurry solid content C expressed as mass fraction x The calculation formula is:

[0077]

[0078] Among them, C s is the solid content of slurry, g / L; ρ t is the density of the slurry at temperature t℃, kg / L;

[0079] Slurry solid content C s The calculation formula is:

[0080]

[0081] Where ρ1 is the density of the aqueous solution in the slurry at temperature t℃, kg / L; ρ s is the true density of slurry solid matter, kg / L.

[0082] After testing, it is found that the wet flue gas desulfurization demister droplet sampling system and slurry droplet content calculation method described in the present invention can not only realize the accurate capture of target droplets in the flue gas at the demister outlet, but also can further accurately measure and calculate the slurry droplet content in the flue gas based on the collected target droplets. Therefore, it is possible to accurately judge whether the flue gas at the demister outlet will cause gypsum rain based on the measured slurry droplet content, and timely take corresponding treatment measures when the slurry droplet content exceeds the emission standard and will cause gypsum rain.

[0083] Example 2

[0084] Referring to the implementation of Example 1, the difference therefrom is that a filter membrane is provided at the air-incoming end of the filter screen 35; in step S1, the formula for determining the specification of the sampling nozzle 32 of the droplet collector 3 according to the flow rate of the flue gas in the flue gas duct at the demister outlet includes:

[0085]

[0086] Where, d is the diameter of the sampling nozzle, mm; Q' r is the rotor flowmeter reading of the constant speed sampling flow, L / min; V s is the gas velocity at the measuring point, m / s; B a is atmospheric pressure, Pa; P s is the exhaust static pressure, Pa; P r is the gas pressure before the rotor flowmeter, Pa; t s is the exhaust temperature, °C; t r is the gas temperature before the rotor flowmeter, ℃; X sw is the volume percentage of the moisture content in the exhaust gas, %; the sampling nozzle 32 includes a nozzle and a tube body connected to the nozzle, the diameter of the nozzle is calculated to be 6 mm, and the diameter of the tube body is 8 mm.

[0087] It has been tested that the wet flue gas desulfurization mist eliminator droplet sampling system and slurry droplet content calculation method described in the present invention can further effectively improve the collection accuracy of target droplets in flue gas compared with the solution in Example 1.

[0088] Example 3

[0089] Refer to Example 2 for implementation, except that, before step S2, it also includes: soaking and cleaning the droplet collector 3 with potassium dichromate lotion, then rinsing it with deionized water, drying it at 105°C for 2h, and finally installing it after cooling to room temperature; before step S3, it also includes an airtightness check of the entire sampling system.

[0090] It has been found that the wet flue gas desulfurization mist eliminator droplet sampling system and slurry droplet content calculation method described in the present invention can further improve the measurement and calculation accuracy of the slurry droplet content in the flue gas compared to the solution in Example 2.

[0091] The wet flue gas desulfurization demister droplet sampling system and slurry droplet content calculation method provided by the present invention, through the design of a droplet collector used in conjunction with the flue gas and dust meter, can make the collected flue gas at the demister outlet freely collide under the action of the trapezoidal folding tube and the serpentine tube, and carry out droplet interception under the action of the filter, thereby realizing the accurate capture of the target droplets in the flue gas, and further by measuring the slurry droplet content in the collected target droplets, it is possible to accurately judge whether the flue gas at the demister outlet will cause gypsum rain based on the measured slurry droplet content, and timely take corresponding treatment measures when the slurry droplet content exceeds the emission standard and will cause gypsum rain.

[0092] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A wet desulfurization mist eliminator droplet sampling system, characterized in that: The wet flue gas desulfurization mist demister droplet sampling system comprises a flue gas and dust meter and a droplet collector (3), wherein the droplet collector (3) comprises a shell (31), the interior of the shell (31) being divided into a first cavity for arranging a trapezoidal folded tube (33) and a second cavity for arranging a serpentine tube (34) and a filter (35), the inlet of the trapezoidal folded tube (33) being connected to a sampling nozzle (32) arranged on the outer surface of the first cavity, and the outlet being connected to the inlet of the serpentine tube (34), the filter (35) being arranged on the rear side of the outlet of the serpentine tube (34), and the outlet end of the second cavity being detachably mounted on the flue gas and dust meter.

2. The wet desulfurization demister droplet sampling system according to claim 1 is characterized in that: The diameter of the trapezoidal folded tube (33) is 8-16 mm and the bending angle is 35-60°, the diameter of the serpentine tube (34) is 4-8 mm, and the droplet filtering accuracy of the filter screen (35) is 15-25 μm.

3. The wet desulfurization demister droplet sampling system according to claim 1 or 2, characterized in that: The air-incoming end of the filter screen (35) is provided with a filter membrane; the sampling nozzle (32) comprises a nozzle and a tube body connected to the nozzle, the diameter of the nozzle is 4-20 mm, and the diameter of the tube body is 6-10 mm.

4. The wet desulfurization demister droplet sampling system according to claim 1, characterized in that: The smoke and dust instrument comprises a sampling smoke gun and an analysis and measurement device (8), and the outlet end of the second cavity is detachably mounted on a droplet collector mounting cylinder (4) of the sampling smoke gun.

5. The wet desulfurization demister droplet sampling system according to claim 1, characterized in that: The droplet catcher (3) is made of stainless steel or titanium alloy.

6. A method for calculating the droplet content of wet desulfurization mist eliminator slurry, characterized in that: Applied to the droplet sampling system described in any one of claims 1 to 5, the slurry droplet content calculation method comprises the following steps: S1. Determine the specification of the sampling nozzle (32) of the droplet collector (3) according to the flow rate of the flue gas in the flue gas duct at the outlet of the demister; S2, installing the droplet collector (3) on the droplet collector mounting tube (4) of the sampling gun of the flue gas and smoke meter; S3, using the analysis and measurement device (8) of the flue gas and dust meter to perform parallel automatic sampling, and keeping the suction speed of the sampling nozzle (32) equal to the air flow speed at the measurement point during the sampling process, and at the same time turning on the heating device (5) of the sampling smoke gun to keep the temperature of the droplet collector (3) and the sampling tube (6) of the sampling smoke gun at 100-120° C.; S4. After the flue gas sampling is completed, the droplet catcher (3) is removed, and the inside of the droplet catcher (3) is rinsed with deionized water in a laboratory environment. The washing liquid is collected in a volumetric flask, and concentrated nitric acid is added to acidify it, and the volume is fixed to the mark with deionized water to obtain the magnesium ion concentration C1 of the droplet catcher absorption solution; at the same time, the magnesium ion concentration C2 of the slurry liquid phase of the desulfurization absorption tower is collected; S5. Calculate the slurry droplet content in the flue gas based on the obtained magnesium ion concentration C1 of the droplet collector absorption solution and the magnesium ion concentration C2 of the slurry liquid phase in the desulfurization absorption tower.

7. The method for calculating the droplet content of the wet desulfurization mist eliminator according to claim 6, characterized in that: Slurry droplet content in flue gas C yd The calculation formula is: Among them, C yd is the slurry droplet content in the flue gas, mg / m 3 ; C1 is the magnesium ion concentration of the droplet collector absorption solution, mg / L; V d is the fixed volume of the droplet collector absorption solution, mL; C2 is the magnesium ion concentration of the absorption tower slurry liquid phase, mg / L; V g is the volume of flue gas (standard, dry), m 3 ; C x is the solid content of the absorber slurry expressed as mass fraction, %.

8. The method for calculating the droplet content of the wet desulfurization mist eliminator according to claim 7, characterized in that: Absorber slurry solid content C expressed as mass fraction x The calculation formula is: Among them, C s is the solid content of slurry, g / L; ρ t is the density of the slurry at temperature t℃, kg / L.

9. The method for calculating the droplet content of the wet desulfurization mist eliminator according to claim 8, characterized in that: Slurry solid content C s The calculation formula is: Where ρ1 is the density of the aqueous solution in the slurry at temperature t℃, kg / L; ρ s is the true density of slurry solid matter, kg / L.

10. The method for calculating the droplet content of the wet desulfurization mist eliminator according to claim 6, characterized in that: In step S1, the formula for determining the specifications of the sampling nozzle (32) of the droplet collector (3) according to the flow rate of the flue gas in the flue gas duct at the outlet of the demister includes: Where, d is the diameter of the sampling nozzle, mm; Q' r is the rotor flowmeter reading of the constant speed sampling flow, L / min; V s is the gas velocity at the measuring point, m / s; B a is atmospheric pressure, Pa; P s is the exhaust static pressure, Pa; P r is the gas pressure before the rotor flowmeter, Pa; t s is the exhaust temperature, °C; t r is the gas temperature before the rotor flowmeter, ℃; X sw is the volume percentage of moisture content in the exhaust gas, %.

11. The method for calculating the droplet content of the wet desulfurization mist eliminator according to any one of claims 6 to 10, characterized in that: Before step S2, the method further includes: soaking and cleaning the droplet collector (3) with potassium dichromate solution, then rinsing it with deionized water, drying it at 100-110° C. for 1-3 hours, and finally installing it after cooling it to room temperature.

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