Wet flue gas purification and material recovery device and method for kiln bypass
By adopting wet flue gas purification and material recovery devices in industrial kilns, the problems of crust blockage and emissions inadequate standards caused by the increase in potassium, sodium, chlorine content are solved, flue gas purification and potassium salt recycling are achieved, and the operation efficiency and economicality of the kilns are improved.
Patent Information
- Application Number
- CN202411694849.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-25
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Industrial kilns, especially cement furnaces, use alternative fuels or coordinated disposal of garbage, lead to increased potassium, sodium, and chlorine content, resulting in clogging of crust, increased operating energy consumption and insufficient emissions.
The kiln bypass wet flue gas purification and material recovery device is adopted, including a multi-stage washing and purification chamber and a three-fold channel mist degreaser. Through spray washing and degreasing treatment technology, the flue gas is purified and valuable potassium salt is recovered.
It effectively reduces the emission concentration of ammonia oxides and dust, meets the standards for emissions, and at the same time recovers potassium salt, reduces waste treatment costs, and improves the operating efficiency of the kiln.
Smart Images
Figure CN119499857A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of energy conservation and environmental protection, and specifically relates to a kiln bypass wet flue gas purification and material recovery device and method. Background Art
[0002] Industrial kilns, especially cement kilns that use alternative fuels or co-dispose of waste, usually bring unfavorable factors to the stable operation of the kiln because the alternative fuels or waste contain higher content of potassium, sodium and chlorine elements than the original fuel. The most common one is the blockage of the furnace wall and the channel under high temperature environment, which causes the channel cross-sectional area to decrease, and the operating energy consumption and failure rate to increase.
[0003] For this reason, for example, cement kilns have introduced dry bypass ventilation technology, that is, through negative pressure suction of fuel-containing exhaust gas in the combustion furnace and mixing and cooling with blown air, solid ash containing potassium and sodium is obtained outside the system to reduce the crusting phenomenon caused by alkaline components such as potassium and chlorine in the dense furnace. Because a large amount of air needs to be blown in for cooling, the operating load of the additional system is large, and at the same time, ammonia oxides cannot be purified, resulting in substandard emissions, which limits the ability of this technology to purify gas-solid hot melts. Therefore, this method is suitable for situations where the concentration or enrichment of potassium, sodium and chlorine in the kiln is not high.
[0004] Industrial kilns, especially cement kilns, have been continuously increasing the proportion of alternative fuels in recent years. In addition, in order to reduce costs and increase efficiency, most kilns will jointly dispose of hazardous wastes, domestic garbage and other solid wastes, which has caused the potassium, sodium and chlorine content in the kilns to continue to rise. For this reason, the kilns need to further increase the air volume. If the traditional dry bypass air release technology is continued to be used, on the one hand, the load of the treatment system will be difficult to continue to increase, and on the other hand, the large amount of potassium, sodium and chlorine solid ash collected will be difficult to digest, and the cost of external transportation and disposal is quite high. In addition, potassium salt has a certain economic value, which causes waste.
[0005] Although the existing patent CN116123878A provides a new type of water-cooled bypass venting coupled SNCR system, in which the excessive harmful components in the cement kiln system are harmlessly disposed of to solve the problem of crusting and blockage caused by the circulation and enrichment of harmful components in the system, in fact, the invention does not carry out the harmless treatment of harmful components. At the same time, it is found through use that the invention does not take into account the serious problem of crusting of the desulfurization temperature range and the combustion flue gas in this temperature range. Summary of the invention
[0006] In view of the problems in the related art, the present invention proposes a kiln bypass wet flue gas purification and material recovery device and method to overcome the above-mentioned technical problems existing in the existing related art.
[0007] To this end, the specific technical scheme adopted by the present invention is as follows: a kiln bypass wet flue gas purification and material recovery device, comprising: a tank body, the bottom of the tank body is respectively provided with a fuel waste gas inlet and a waste water outlet, and the top is provided with a purified gas outlet; the tube wall of the tank body is an annular cavity, and the interior of the tank body is sequentially provided with a multi-stage washing and purification chamber and a three-fold channel demister from bottom to top, and the multi-stage washing and purification chamber is connected to each other The washing and purification chambers are stacked together; each washing and purification chamber is connected to an annular cavity, and the annular cavity is also connected to the wastewater outlet to form a wastewater discharge circuit, wherein is a positive integer; Also includes: Water mist spray assembly and A temperature sensor is installed in the The washing and purification chamber is provided with a washing and purification group; wherein the Room temperature threshold for group washing cleanroom The gradient decreases from bottom to top; an induced draft fan connected to the purified gas outlet through a pipeline; A chimney is connected to the induced draft fan through a pipeline; an online flue gas monitor is installed in the chimney; The air blower is installed between the fuel exhaust gas inlet and the smoke chamber through a pipeline; the execution instruction of the air blower comes from the smoke online monitor.
[0008] In a further embodiment, the first group of washing and purification chambers to the The structures of the washing and purification chambers of the two groups are the same, and both include: a first guide plate, a second guide plate, a guide support and a chamber support; wherein, ; No. The washing and purification chamber comprises: a first guide plate, a second guide plate and a guide support; Wherein, the connecting end of the first guide plate is inclined at a predetermined angle on the inner wall surface of the tube wall; a first guide gap is left between the movable end of the first guide plate and the inner wall surface of the adjacent tube wall; The second guide plate is located above the first guide plate and is arranged opposite to the first guide plate; the connecting end of the second guide plate is arranged on the inner wall surface of the tube wall at an inclined angle according to a predetermined angle; a second guide gap is left between the movable end of the second guide plate and the inner wall surface of the tube wall adjacent thereto; Correspondingly, the guide support is used to connect the first guide plate and the second guide plate in the same group of washing and purification chambers, and the chamber support is used to connect the first guide plate and the second guide plate in the adjacent groups of washing and purification chambers.
[0009] In a further embodiment, the annular cavity is formed by an inner wall surface and an outer wall surface having a predetermined distance; There are several circles of holes on the inner wall surface, and each circle of holes is respectively opened above the connection between the first guide plate and the inner wall surface, or above the connection between the second guide plate and the inner wall surface.
[0010] In a further embodiment, the three-fold channel demister comprises: Two sets of sealing plates are symmetrically filled in the tank body; the sealing plates have a predetermined thickness; A plurality of cooling water flow channels are radially arranged in parallel between the two groups of sealing plates according to a predetermined gap; two adjacent groups of cooling water flow channels are connected by channel connecting pipes, and the channel connecting pipes of the two adjacent groups are staggered, and the predetermined gap forms a smoke flow channel.
[0011] In a further embodiment, the cooling water flow passage is axially "S"-shaped; correspondingly, the smoke flow passage is axially "S"-shaped; the "S"-shaped is formed by multiple arc segments connected end to end, and the central angle of the arc ranges from 55° to 70°; Wherein, the cooling water flow channel located at the edge is provided with a circulating cooling water inlet.
[0012] In a further embodiment, the water mist spray assembly comprises: At least one group of atomizing nozzles is arranged below the first guide plate and / or the second guide plate in each group of washing and purification chambers; The distribution water pipe is connected to the atomizing nozzle correspondingly; the distribution water pipe is provided with a control magnetic valve.
[0013] In a further embodiment, the apparatus further comprises: An inclined plate sedimentation tank, connected to the wastewater discharge outlet; A stirring tank, the input end of which is connected to the output end of the inclined plate sedimentation tank; The input end of the centrifugal dehydrator is connected to the output end of the stirring tank; the output end of the centrifugal dehydrator is respectively connected to the liquid treatment equipment and the sedimentation treatment equipment.
[0014] The purification and recovery method using the kiln bypass wet flue gas purification and material recovery device as described above comprises the following steps: Start the water mist spray assembly in advance to create the required flue gas washing environment in the multi-stage washing and purification chamber; start the induced draft fan to draw the fuel exhaust gas from the smoke chamber into the tank body through the fuel exhaust gas inlet; the fuel exhaust gas flows upward from bottom to top through the multi-stage washing and purification chamber, and the following steps are performed each time it passes through a group of washing and purification chambers: Construct a model for calculating the residence time of the scrubbing and purification chambers to calculate the residence time of the fuel exhaust gas in each group of scrubbing and purification chambers. Stay time within ; At the same time, a water injection calculation system is created based on the current parameters and real-time temperature of the fuel exhaust gas Calculate the washing and purification room The amount of water sprayed inside ; By the residence time and water spray volume Control corresponding washing and purification room Chamber outlet temperature close to a given room temperature threshold ,in, ; The wastewater washed by each group of washing and purification chambers is discharged through the wastewater discharge circuit, and the fuel waste gas is washed and cooled by the multi-stage washing and purification chambers, and then defogged by the three-fold channel demister and discharged into the chimney through the purified gas outlet; The flue gas online monitor detects the nitrogen oxide concentration to obtain the test results, and feeds the test results back to the air blower to control the air supply in the tank.
[0015] In a further embodiment, the construction process of the washing and cleaning chamber residence time calculation model is as follows: According to the two adjacent groups of washing and purification rooms and washing and purification room Chamber outlet temperature , Calculate the current washing and purification room The arithmetic mean of the inlet and outlet temperature differences ; Get the height-to-diameter ratio of the straight pipe section of the tank , cross-sectional diameter and internal standard pressure ; The following formula is used to express the calculation model of the washing and purification chamber residence time: ; In the formula, It is the standard dry flow rate of fuel exhaust gas, expressed by absolute dry air in standard state; Correspondingly, the total residence time T of the fuel exhaust gas in the tank is calculated as follows: .
[0016] In a further embodiment, the steps of establishing the water spray volume calculation system are as follows: Washing and purification room The amount of water sprayed inside Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ; In the formula, is the outlet temperature of the m+1th stage washing and purification chamber, is the chamber outlet temperature of the m-th stage washing and purification chamber; All washing and purification rooms The amount of water sprayed Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ; In the formula, is the specific heat of flue gas, represents the specific heat of dust particles, It is expressed in terms of absolute dry air under standard conditions. is the wastewater temperature collected during step cooling. is the specific heat of water, is the initial temperature of the spray water, represents the inlet temperature of the three-fold channel demister, Indicates the initial flue gas temperature.
[0017] Beneficial effects of the present invention: The main body of the temperature-controlled spray washing device of the present invention is a circular tank structure, which consists of an external annular cavity chamber and an internal flue gas washing and purification chamber. Inclined guide plates are arranged vertically and overlapped in the purification chamber. The angle of the inclined guide plates is not less than 5°, and the value range is [5°~10°]. The flue gas at the bottom enters and then flows upflow along the way. Pipe fittings and atomizing nozzles are inserted directly below the connection between the guide plate and the wall of the device to flow in the same direction as the flue gas, and the flue gas is mixed with the atomized water droplets by utilizing the turbulent state of the flue gas deflection. At the same time, a hole is opened at the upper part of the connection to facilitate the sedimentation and collection of wastewater to flow into the external wastewater diversion chamber. A temperature sensor is inserted into the wall directly opposite the nozzle to monitor the temperature and adjust the atomization water spray volume.
[0018] After the purification processes such as spray washing of solids and migration of ammonia oxides and melt water, the flue gas needs to be cooled and dehumidified by the three-fold channel demister. The circulating water channel and the humid air flow channel are separated, and the material components do not interfere with the heat conduction only through the partition wall. The height difference H of the circulating cooling water inlet connecting the pipeline is not less than 0.5m, which can ensure the closed circulating water flow pipe to overcome friction and flow normally. The three-fold bend angle value is designed in the range of 55°~70° to significantly increase the probability of inertial collision between water droplets and particle droplets, and the removal efficiency is high.
[0019] The main body of the temperature-controlled spray fume purification device of the present invention is provided with a plurality of washing and purification chambers, and the ideal residence time is obtained by calculation to avoid secondary production of crusting in the temperature range of 200-400°C. At the same time, a temperature sensor is installed at the bottom of the atomizing nozzle to better monitor the temperature and adjust the water spraying amount, and it is not affected by the water spraying and scaling at the top.
[0020] At the same time, the bypass connection design is optimized, specifically: the exhaust volume of the present invention can reach 5% to 15% of the total standard dry flue gas volume of the coal-fired kiln flue gas, and is particularly suitable for the purification and material recovery of the bypass exhaust volume of more than 10% of the cement kiln.
[0021] The purification and material recovery of hot flue gas containing solids in bypass ventilation is realized by a two-stage process method. First, the air oxidation and water-soluble migration of nitrogen oxides are completed in the main body of the temperature-controlled spray flue gas purification device; in addition, the high-temperature molten gaseous potassium, sodium and chlorine components in the hot flue gas are fully contacted with the sprayed water mist to cool down, forming uniform and smaller solids, which are washed by the water mist and fall together with the particulate matter contained in the flue gas. After the droplets and particles are collided and collected by the three-fold channel demister at the top of the device, they flow into the wastewater collection pipe. The concentration of nitrogen oxides in the discharged flue gas is reduced by no less than 80% and the dust concentration is low to meet the emission standards, and the emptying temperature does not exceed 50°C. Secondly, the wastewater collected by the device undergoes precipitation, neutralization flocculation, solid-liquid separation and evaporation crystallization processes to obtain potassium salt and dehydrated mineral powder, which can be recycled and reused as resources.
[0022] The online flue gas monitor is linked to the air blower. The air supply of the blower is controlled by analyzing the concentration of ammonia oxides in the exhaust flue gas. The amount of air blown in is about 10% to 15% of the total standard dry weight of the bypass flue gas to ensure that there is sufficient oxygen content in the environment for oxidizing ammonia oxides.
[0023] In the main structure of the temperature-controlled spray flue gas purification device, the wall temperature sensor and the PLC controller are used to control the valve opening on the distribution water pipe and adjust the water spray volume in a timely manner. The wastewater sedimentation uses an inclined plate sedimentation tank, which has high separation efficiency, a large contact surface with the air, and is easy to dissipate heat, and has high space utilization under the same floor area. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a connection diagram of the kiln bypass wet flue gas purification and material recovery device.
[0025] Figure 2 It is a partial connection diagram of the kiln bypass wet flue gas purification and material recovery device.
[0026] Figure 3 It is a schematic diagram of a multi-stage washing purification chamber.
[0027] Figure 4 It is a partial enlarged view of the inner wall of the device.
[0028] Figure 5 It is a transverse cross-section of a three-fold channel demister.
[0029] Figure 6 It is a longitudinal section view of a three-fold channel demister.
[0030] Figures 1 to 6The labels in are: tank 1, fuel exhaust gas inlet 2, wastewater outlet 3, multi-stage washing and purification chamber 4, three-fold channel demister 5, induced draft fan 6, chimney 7, flue gas online monitor 8, air blower 9, atomizing nozzle 10, distribution water pipe 11, temperature sensor 12, inclined plate sedimentation tank 13, stirring tank 14, centrifugal dehydrator 15, temporary storage tank 16, heat exchanger 17, evaporator 18, steam compressor 19, separator 20, plate and frame filter press 21, Control magnetic valve 22, annular cavity 101, inner wall surface 101-a, hole 101-b, first group of washing and purification chambers 401, second group of washing and purification chambers 402, third group of washing and purification chambers 403, fourth group of washing and purification chambers 404, first guide plate 405, second guide plate 406, guide support 407, chamber support 408, sealing plate 501, cooling water flow channel 502, channel connecting pipe 503, flue gas flow channel 504. DETAILED DESCRIPTION
[0031] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention.
[0032] Example 1 like Figure 1 As shown, this embodiment provides a kiln bypass wet flue gas purification and material recovery device, including a tank body 1. The tank body 1 in this embodiment is a round tank structure, and a fuel exhaust gas inlet 2 and a wastewater outlet 3 are respectively opened at the bottom, and a purified gas outlet is arranged on the top. In conjunction with the figure, the purified gas outlet is connected to an induced draft fan 6 through a pipeline, and the induced draft fan 6 is used to control the air discharge volume inside the device, that is, the flow rate of the fuel exhaust gas in the device. The induced draft fan 6 transports the purified gas to the chimney 7 for discharge. In order to further ensure that the exhaust gas is a qualified gas, an online flue gas monitor 8 is installed in the chimney 7. The online flue gas meter is used to monitor the concentration of ammonia oxides, and the signal processor feeds back to the air blower 9 for operating frequency adjustment to ensure sufficient air volume to oxidize NO x It is NO2, which is easy to dissolve in water and migrate to purify flue gas.
[0033] Correspondingly, the fuel exhaust gas inlet 2 is connected to the smoke chamber via a pipeline and an air blower 9 is installed therebetween. The execution instructions of the air blower 9 are derived from the smoke online monitor 8 .
[0034] In order to achieve efficient collection and treatment of wastewater, the tube wall of the tank body 1 of this embodiment is an annular cavity 101. In other words, the tube wall itself is a hollow structure formed by an inner wall surface 101-a and an outer wall surface with a predetermined distance.
[0035] At the same time, considering that the fuel exhaust gas has a certain amount of heat and impurity particles, a multi-stage washing and purification chamber 4 and a three-fold channel demister 5 are sequentially arranged in the interior of the tank body 1 from bottom to top; the multi-stage washing and purification chamber 4 is composed of interconnected The plurality of washing and purification chambers are stacked. Each group of washing and purification chambers is connected to the annular cavity chamber 101, and the annular cavity chamber 101 is also connected to the wastewater discharge port 3 to form a wastewater discharge loop, where n is a positive integer. In other words, the fuel exhaust gas is graded and reduced by the multi-stage washing and purification chambers in this embodiment, and finally the three-fold channel demister 5 is used for demisting.
[0036] To ensure the effectiveness of washing and cooling, it also includes: Water mist spray assembly and A temperature sensor 12 is installed correspondingly in the In the washing purification room, Temperature threshold for the cleaning room There is a decreasing gradient from bottom to top.
[0037] like Figure 2 and Figure 3 As shown, this embodiment takes n=4 as an example, that is, the washing and purification chambers are stacked in four groups from bottom to top, including: a first group of washing and purification chambers 401, a second group of washing and purification chambers 402, a third group of washing and purification chambers 403 and a fourth group of washing and purification chambers 404. , the second set of washing and purification chamber 402 , the third group of washing and purification chamber 403 , the fourth group of washing and purification chamber 404 It can be seen that the room temperature thresholds of the four groups of washing and purification rooms are It shows a gradient decreasing trend from bottom to top, which is beneficial to ensure the process effect.
[0038] The setting of the above temperature thresholds needs to meet the following requirements: the setting of the temperature threshold of the second group of washing and purification chambers 402 is to ensure that the solid particles are formed quickly and are relatively uniform and small, which is conducive to the migration of potassium, sodium and chlorine alkaline components dissolved in water; the setting of the temperature threshold of the third group of washing and purification chambers 403 is to ensure the required residence time and avoid the secondary production of dioxins in the temperature range of 200-400°C. For specific temperature threshold settings, please refer to Example 2.
[0039] In a further embodiment, the first group of washing and purification chambers to the first group of washing and purification chambers are shown in FIG. The structures of the washing and purification chambers of the groups are the same, and both include: a first guide plate 405, a second guide plate 406, a guide support 407 and a chamber support 408; wherein, ; That is, the first group of washing and purification chambers 401, the second group of washing and purification chambers 402 and the third group of washing and purification chambers 403 shown in the figure.
[0040] No. The group of washing and purification chambers includes: a first guide plate 405, a second guide plate 406, and a guide support 407; that is, the fourth group of washing and purification chambers 404 shown in the figure.
[0041] The specific installation form is as follows: the connecting end of the first guide plate 405 is inclined at a predetermined angle on the inner wall surface 101-a of the tube wall; a first guide gap is left between the movable end of the first guide plate 405 and the inner wall surface 101-a of the adjacent tube wall.
[0042] The second guide plate 406 is located above the first guide plate 405 and is arranged opposite to the first guide plate 405; the connecting end of the second guide plate 406 is inclined at a predetermined angle on the inner wall surface 101-a of the tube wall; a second guide gap is left between the movable end of the second guide plate 406 and the inner wall surface 101-a of the adjacent tube wall. Correspondingly, the guide support 407 is used to connect the first guide plate 405 and the guide plate in the same group of washing and purification chambers, and the chamber support 408 is used to connect the first guide plate 405 and the guide plate in the adjacent group of washing and purification chambers.
[0043] The predetermined angle is , and more preferably 5°. The selection of this angle takes into account the relationship between the size and shape of the solids in the confluent wastewater and the diversion angle, that is, it is conducive to the flow of the washing wastewater to the wall surface.
[0044] It is worth mentioning that the first guide plate 405 and the second guide plate 406 in the first group of washing and purification chambers 401, the second group of washing and purification chambers 402, the third group of washing and purification chambers 403 and the fourth group of washing and purification chambers 404 are all installed in the same staggered and inclined manner. At the same time, taking the guide support 407 in the first group of washing and purification chambers 401 as an example, it is used to connect the first guide plate 405 and the second guide plate 406 in the first group of washing and purification chambers 401. And the chamber support 408 in the first group of washing and purification chambers 401 is used to support the second guide plate 406 of the first group of washing and purification chambers 401 and the first guide plate 405 of the second group of washing and purification chambers 402, so as to be staggered and connected.
[0045] The fourth group of washing and purification chambers 404 is arranged at the top layer, so it is different from other groups of washing and purification chambers in that it does not include chamber support 408. The flow guide support 407 and chamber support 408 are arranged at intervals so as not to affect the flow of wastewater. In addition, the atomized water droplets and the air flow flow in the same direction to reduce the system resistance and realize the long-distance deflection of all solid hot flue gas.
[0046] The above technical solution realizes that the flue gas at the bottom enters and flows in an upward flow pattern. The pipe and the atomizing nozzle 10 are extended directly below the connection between the first guide plate 405, the second guide plate 406 and the wall of the device, and flow in the same direction as the flue gas, and the flue gas is mixed with the atomized water droplets by utilizing the turbulent flow of the flue gas.
[0047] Suitable for it, such as Figure 4 As shown, the annular cavity 101 is formed by an inner wall surface 101-a and an outer wall surface having a predetermined distance; wherein, the inner wall surface 101-a is provided with a plurality of circles of holes 101-b, and each circle of holes 101-b is respectively provided above the connection between the first guide plate 405, the second guide plate 406 and the inner wall surface 101-a.
[0048] That is, in order to ensure that all wastewater is collected, circle holes 101-b are correspondingly arranged above each first guide plate 405 and second guide plate 406, and holes are opened at the top of the connection to facilitate the sedimentation and collection of wastewater to flow into the external wastewater diversion chamber.
[0049] Combination Figure 5 and Figure 6 The three-fold channel demister 5 includes: two groups of sealing plates 501 symmetrically filled in the tank body 1, and the sealing plates 501 have a predetermined thickness. It also includes: a plurality of cooling water flow channels 502 arranged in parallel between the two groups of sealing plates 501 along the radial direction according to a predetermined gap, and the two adjacent groups of cooling water flow channels 502 are connected through channel connecting pipes 503, and the two adjacent groups of channel connecting pipes 503 are staggered. The predetermined gap forms a flue gas flow channel 504. After the purification process such as spray washing solids and ammonia oxide melt water migration, the flue gas needs to be cooled and dehumidified by the three-fold channel demister 5 demister, and the circulating water channel and the humid air flow channel are separated, and the material components do not interfere with the heat conduction of the partition wall.
[0050] In order to increase the defog effect, the cooling water flow channel 502 is "S"-shaped along the axial direction, and correspondingly, the smoke flow channel 504 is "S"-shaped in the axial direction; the "S" shape is formed by multiple arc sections connected end to end, and the central angle range of the arc is 55°~70°; wherein, the cooling water flow channel 502 located at the edge is provided with a circulating cooling water inlet.
[0051] Among them, the height difference H of the circulating cooling water inlet connecting pipe is not less than 0.5m, which can ensure the closed circulating water flow pipe to overcome friction and flow normally. The design range of the three-bend angle value is 55°~70°, which significantly reduces the flue gas temperature and gas humidity, so that the moisture content, particulate matter concentration and air temperature of the purified gas are low, especially the dilution after connecting to the kiln tail emission chimney 7, so that the emission can meet the standard.
[0052] In another embodiment, n groups of water mist spraying assemblies are correspondingly installed in n groups of washing and purification chambers, and the water mist spraying assemblies include: At least one group of atomizing nozzles 10 is arranged below the first guide plate 405 or / and the second guide plate 406 in each group of washing and purification chambers; the atomizing nozzles 10 are connected to the distribution pipes 11, and the distribution pipes 11 are equipped with control magnetic valves 22. Further, the temperature sensor 12 is correspondingly installed below the atomizing nozzles.
[0053] Specifically, the first group of washing and purification chambers 401 to the The first group of washing and purification chambers 401 to the second group of washing and purification chambers are equipped with atomizing nozzles 10 in the first guide gap and the second guide gap, and the atomizing nozzles 10 are correspondingly located below the first guide plate 405 or the second guide plate 406. Two groups of atomizing nozzles 10 are arranged in the washing and purification chamber.
[0054] No. The washing and purification chamber is provided with an atomizing nozzle 10 in the first guide gap.
[0055] At the same time, in order to ensure the accuracy of temperature acquisition, a temperature sensor 12 is installed below the atomizing nozzle 10 adjacent to the outlet, so as to better monitor the temperature and adjust the water spraying amount without being affected by the upper water spraying and scaling.
[0056] In other embodiments, in combination Figure 1 The device also includes: an inclined plate sedimentation tank 13 connected to the wastewater discharge port 3, a stirring tank 14 connected to the output end of the inclined plate sedimentation tank 13, and a centrifugal dehydrator 15 connected to the stirring tank 14. The output end of the centrifugal dehydrator 15 is respectively connected to the liquid treatment equipment and the sedimentation treatment equipment, wherein the liquid treatment equipment can be a temporary storage tank 16, a heat exchanger 17, an evaporator 18, a steam compressor 19, a separator 20, etc. The sedimentation treatment equipment can be a plate and frame filter press 21, etc. The treated water is used for other municipal needs.
[0057] In this embodiment, after the hot flue gas is vented through the bypass for process optimization and material recovery, the original chimney 7 is used for reception, that is, all the waste gas is discharged into the chimney 7 at the end of the kiln. The existing emission indicators will face certain pressure, especially the oxides. Usually, the NOx volume fraction in the kiln smoke chamber is about 0.10%, and the oxygen content is 6-8%. The traditional dry technology cannot purify and remove the ammonia oxides. The present invention adopts the "wet water reaction combined with air oxidation" technology to maximize the migration of ammonia oxides into the wastewater, ensuring that the purified flue gas is diluted by the original chimney 7, and can still meet the emission standards.
[0058] The main chemical reactions involved are as follows: 2NO+O2=2NO2; 3NO2+H2O=2HNO3+NO; The oxygen content in the air is 21%, far exceeding the 6-8% oxygen content in the dense furnace smoke chamber. The nitrogen oxide value can be monitored online by the dense tail chimney, and the signal is fed back to the air blower operating frequency, and the air volume is determined by the chemical equation calculation formula. Ammonia oxides are finally dissolved in the wastewater (NO2, N2O3; soluble in water), and nitrogen oxides are transferred from the flue gas to the liquid water for subsequent treatment to purify the flue gas.
[0059] Example 2 Based on the kiln bypass wet flue gas purification and material recovery device disclosed in Example 1, this embodiment discloses a purification and recovery method, including the following process: Start the water mist spray assembly in advance to create the required flue gas washing environment in the multi-stage washing and purification chamber; start the induced draft fan to draw the fuel exhaust gas from the smoke chamber into the tank body through the fuel exhaust gas inlet; the fuel exhaust gas flows upward from bottom to top through the multi-stage washing and purification chamber, and the following steps are performed each time it passes through a group of washing and purification chambers: Construct a model for calculating the residence time of the scrubbing and purification chambers to calculate the residence time of the fuel exhaust gas in each group of scrubbing and purification chambers. Stay time within ; At the same time, a water injection calculation system is created based on the current parameters and real-time temperature of the fuel exhaust gas Calculate the washing and purification room The amount of water sprayed inside ; By the residence time and water spray volume Control corresponding washing and purification room Chamber outlet temperature close to a given room temperature threshold ,in, ; The wastewater washed by each group of washing and purification chambers is discharged through the wastewater discharge circuit, and the fuel waste gas is washed and cooled by the multi-stage washing and purification chambers, and then defogged by the three-fold channel demister and discharged into the chimney through the purified gas outlet; The flue gas online monitor detects the nitrogen oxide concentration to obtain the test results, and feeds the test results back to the air blower to control the air supply in the tank.
[0060] Furthermore, the construction process of the washing and purification chamber residence time calculation model is as follows: According to the two adjacent groups of washing and purification rooms and washing and purification room Chamber outlet temperature , Calculate the current washing and purification room The arithmetic mean of the inlet and outlet temperature differences ; It can be further understood as the difference between two adjacent temperature sensors divided by 2.
[0061] Get the height-to-diameter ratio of the straight pipe section of the tank , cross-sectional diameter and internal standard pressure ; Among them, the height-to-diameter ratio of the straight pipe section The value range is (2~4):1.
[0062] The following formula is used to express the calculation model of the washing and purification chamber residence time: ; In the formula, It is the standard dry flow rate of fuel exhaust gas, expressed in standard state absolute dry air; Nm 3 / h; Correspondingly, the total residence time T of the fuel exhaust gas in the tank is calculated as follows: .
[0063] The steps for establishing the water spray volume calculation system are as follows: Washing and purification room The amount of water sprayed inside Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ; In the formula, is the outlet temperature of the m+1th stage washing and purification chamber, is the chamber outlet temperature of the m-th stage washing and purification chamber; All washing and purification rooms The amount of water sprayed Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ; In the formula, is the specific heat of flue gas, and the value in this embodiment is 0.3714 kcal / Nm 3 / ℃; represents the specific heat of dust particles, and the value of this embodiment is 0.244 kcal / kg / ℃; It is expressed in terms of absolute dry air under standard conditions. is the wastewater temperature collected during step cooling. is the specific heat capacity of water, and the value in this embodiment is 1.0 kcal / kg / ℃; is the initial temperature of the spray water, represents the inlet temperature of the three-fold channel demister, Indicates the initial flue gas temperature. In summary, compared with the traditional dry bypass ventilation technology, the wet technology has a better water cooling effect and synchronous water washing and desalination to recover materials.
[0064] The present invention has the advantages of large process system load and simple process, and can be applied to scenes with large air volume. In addition, the wet method only has obvious resistance loss in the temperature-controlled spray flue gas purification device, and the overall resistance is small.
[0065] Specifically, the hot flue gas containing solids is sucked by negative pressure, and in the process of mixing with the sprayed water mist, ammonia oxides are oxidized by air and dissolved in water are transferred, and particulate matter is washed and dissolved in water is captured for purification, so that the flue gas pollutants can be discharged in compliance with the standards.
[0066] Table 1 Application data in three different scenarios The concentration of ammonia oxides is monitored by an online flue gas meter and fed back to the air blower through a signal processor for frequency adjustment to ensure sufficient air volume, oxygen, NO x It is NO2, which is convenient for dissolved water to migrate and purify flue gas; The spray water mist used can elute the potassium, sodium and chloride salt components in the solid-containing flue gas and dissolve them in the wastewater. The wastewater with higher temperature is convenient for efficient evaporation and recovery of potassium salt, and the economic benefits are better than those of dry technology.
[0067] The generated wastewater is subjected to simple sedimentation and mechanical dehydration to obtain mineral powder with low moisture content, which can be directly put into the kiln for reuse. Compared with the subsequent treatment of dry technology, it is more economical. For details, please refer to Table 1, which is an analysis of the application data of the present invention in three different scenarios.
Claims
1. A kiln bypass wet flue gas purification and material recovery device, comprising: The tank body has a fuel exhaust gas inlet and a waste water outlet at the bottom, and a purified gas outlet at the top; the tank body is characterized in that the tube wall of the tank body is an annular cavity, and the inside of the tank body is sequentially provided with a multi-stage washing and purification chamber and a three-fold channel demister from bottom to top, and the multi-stage washing and purification chambers are interconnected. The washing and purification chambers are stacked together; each washing and purification chamber is connected to an annular cavity, and the annular cavity is also connected to the wastewater outlet to form a wastewater discharge circuit, wherein is a positive integer; Also includes: Water mist spray assembly and A temperature sensor is installed in the The washing and purification chamber is provided with a washing and purification group; wherein the Room temperature threshold for group washing cleanroom From bottom to top, the gradient decreases; an induced draft fan connected to the purified gas outlet through a pipeline; A chimney is connected to the induced draft fan through a pipeline; an online flue gas monitor is installed in the chimney; The air blower is installed between the fuel exhaust gas inlet and the smoke chamber through a pipeline; the execution instruction of the air blower comes from the smoke online monitor.
2. The kiln bypass wet flue gas purification and material recovery device according to claim 1 is characterized in that: The first group of washing and purification chambers to The structures of the washing and purification chambers of the two groups are the same, and both include: a first guide plate, a second guide plate, a guide support and a chamber support; wherein, ; No. The washing and purification chamber comprises: a first guide plate, a second guide plate and a guide support; Wherein, the connecting end of the first guide plate is inclined at a predetermined angle on the inner wall surface of the tube wall; a first guide gap is left between the movable end of the first guide plate and the inner wall surface of the adjacent tube wall; The second guide plate is located above the first guide plate and is arranged opposite to the first guide plate; the connecting end of the second guide plate is arranged on the inner wall surface of the tube wall at an inclined angle according to a predetermined angle; a second guide gap is left between the movable end of the second guide plate and the inner wall surface of the tube wall adjacent thereto; Correspondingly, the guide support is used to connect the first guide plate and the second guide plate in the same group of washing and purification chambers, and the chamber support is used to connect the first guide plate and the second guide plate in the adjacent groups of washing and purification chambers.
3. The kiln bypass wet flue gas purification and material recovery device according to claim 1, characterized in that: The annular cavity is formed by an inner wall surface and an outer wall surface having a predetermined distance; There are several circles of holes on the inner wall surface, and each circle of holes is respectively opened above the connection between the first guide plate and the inner wall surface, or above the connection between the second guide plate and the inner wall surface.
4. The kiln bypass wet flue gas purification and material recovery device according to claim 1 is characterized in that: The three-fold channel demister comprises: Two sets of sealing plates are symmetrically filled in the tank body; the sealing plates have a predetermined thickness; A plurality of cooling water flow channels are radially arranged in parallel between the two groups of sealing plates according to a predetermined gap; two adjacent groups of cooling water flow channels are connected by channel connecting pipes, and the channel connecting pipes of the two adjacent groups are staggered, and the predetermined gap forms a smoke flow channel.
5. The kiln bypass wet flue gas purification and material recovery device according to claim 4 is characterized in that: The cooling water flow passage is in an "S" shape along the axial direction; correspondingly, the smoke flow passage is in an "S" shape in the axial direction; the "S" shape is formed by multiple arcs connected end to end, and the central angle range of the arc is 55°~70°; Wherein, the cooling water flow channel located at the edge is provided with a circulating cooling water inlet.
6. The kiln bypass wet flue gas purification and material recovery device according to claim 1, characterized in that: The water mist spray assembly comprises: At least one group of atomizing nozzles is arranged below the first guide plate and / or the second guide plate in each group of washing and purification chambers; The distribution water pipe is connected to the atomizing nozzle correspondingly; the distribution water pipe is provided with a control magnetic valve.
7. The kiln bypass wet flue gas purification and material recovery device according to claim 1, characterized in that: The device also includes: An inclined plate sedimentation tank, connected to the wastewater discharge outlet; A stirring tank, the input end of which is connected to the output end of the inclined plate sedimentation tank; The input end of the centrifugal dehydrator is connected to the output end of the stirring tank; the output end of the centrifugal dehydrator is respectively connected to the liquid treatment equipment and the sedimentation treatment equipment.
8. A purification and recovery method using the kiln bypass wet flue gas purification and material recovery device as described in any one of claims 1 to 7, characterized in that: The following steps are involved: Pre-start the water mist spray assembly to create the required fume scrubbing environment in the multi-stage scrubbing purification room; Start the induced draft fan to draw the fuel exhaust gas from the smoke chamber into the tank through the fuel exhaust gas inlet; the fuel exhaust gas flows upward from bottom to top through the multi-stage washing and purification chambers, and the following steps are performed each time it passes through a group of washing and purification chambers: Construct a model for calculating the residence time of the scrubbing and purification chambers to calculate the residence time of the fuel exhaust gas in each group of scrubbing and purification chambers. Stay time within ; At the same time, a water injection calculation system is created based on the current parameters and real-time temperature of the fuel exhaust gas Calculate the washing and purification room The amount of water sprayed inside ; By the residence time and water spray volume Control corresponding washing and purification room Chamber outlet temperature close to a given room temperature threshold ,in, ; The wastewater washed by each group of washing and purification chambers is discharged through the wastewater discharge circuit, and the fuel waste gas is washed and cooled by the multi-stage washing and purification chambers, and then defogged by the three-fold channel demister and discharged into the chimney through the purified gas outlet; The flue gas online monitor detects the nitrogen oxide concentration to obtain the test results, and feeds the test results back to the air blower to control the air supply in the tank.
9. The purification and recovery method of the kiln bypass wet flue gas purification and material recovery device according to claim 8, characterized in that: The construction process of the washing and purification chamber residence time calculation model is as follows: According to the two adjacent groups of washing and purification rooms and washing and purification room Chamber outlet temperature , Calculate the current washing and purification room The arithmetic mean of the inlet and outlet temperature differences ; Get the height-to-diameter ratio of the straight pipe section of the tank , cross-sectional diameter and internal standard pressure ; The following formula is used to express the calculation model of the washing and purification chamber residence time: ； In the formula, It is the standard dry flow rate of fuel exhaust gas, expressed by absolute dry air in standard state; Correspondingly, the total residence time T of the fuel exhaust gas in the tank is calculated as follows: 。 10. The purification and recovery method of the kiln bypass wet flue gas purification and material recovery device according to claim 7, characterized in that: The steps for establishing the water spray volume calculation system are as follows: Washing and purification room The amount of water sprayed inside Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ; In the formula, is the outlet temperature of the m+1th level washing and purification chamber, is the chamber outlet temperature of the m-th stage washing and purification chamber; All washing and purification rooms The amount of water sprayed Standard dry flow rate of fuel exhaust gas The relationship between them is as follows: ； In the formula, is the specific heat of flue gas, represents the specific heat of dust particles, It is expressed in terms of absolute dry air under standard conditions. is the wastewater temperature collected during step cooling. is the specific heat of water, is the initial temperature of the spray water, represents the inlet temperature of the three-fold channel demister, Indicates the initial flue gas temperature.