Air conveying system and air flow adjusting method

Abstract

The invention discloses an air conveying system which comprises a fan capable of adjusting the conveying amount, the fan is connected with an absorption tower slurry pool used for oxidizing HSO3 <-> in slurry in the absorption tower slurry pool into SO4 < 2->, and the absorption tower slurry pool is connected with a sulfite analyzer used for measuring the concentration of the HSO3 <-> in the slurry in the absorption tower slurry pool. The air conveying system further comprises a control system connected with the fan and the sulfite analyzer. The invention further discloses an air flow adjusting method. According to the air conveying system disclosed by the invention, the conveying capacity of the oxidation fan is adjusted through the fan capable of adjusting the conveying capacity, and meanwhile, the slurry in the slurry tank of the absorption tower is in an optimal oxidation reaction state under the cooperation of the fan and the sulfite analyzer, so that the desulfurization efficiency is improved; the problem that the air volume of an oxidation fan adopted by a limestone-gypsum wet desulphurization system in the prior art cannot be adjusted is solved.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas desulfurization treatment, and in particular to an air conveying system and an air flow regulating method. Background Art

[0002] With the release of the "Aluminum Industry Pollutant Emission Standard" GB 25465 and its amendments, the electrolytic aluminum industry has gradually added flue gas desulfurization systems. Among them, the limestone-gypsum wet desulfurization process has been widely used due to its mature technology and high desulfurization efficiency. The sulfur dioxide in the flue gas of electrolytic aluminum mainly comes from the pre-baked anode, the raw material of its production. Under the high temperature environment of the pre-baked anode in the tank, the sulfur in the anode carbon block is oxidized to generate SO2 and enter the flue gas. At present, the concentration of SO2 in the electrolytic flue gas is mostly 200mg / m 3 -350mg / m 3 It is impossible to meet the emission limit requirements of the "Aluminum Industry Pollutant Emission Standard" and its amendment. According to statistics, there are more than 10 mature and economically scientific process technologies for industrial flue gas desulfurization at home and abroad. Limestone-gypsum wet desulfurization process technology is widely used in the world, among which oxidation blower is the main power equipment of the desulfurization system.

[0003] When the limestone-gypsum wet desulfurization system is running, the oxidation fan compresses the air and blows it into the middle part of the absorption tower slurry pool. The O2 in the air absorbs the HSO3 in the slurry in the absorption tower. - Oxidized to SO4 2- It reacts with CaCO3 in limestone and crystallizes to form gypsum (CaSO4·2H2O). When the sulfur content or flue gas volume in the desulfurized flue gas changes, the required oxidation air volume also changes. Generally, the air volume of the oxidation fan is selected according to the designed flue gas volume and sulfur content, but the actual required oxidation air volume is greatly affected by the total flue gas volume, inlet SO2 concentration and oxidation absorption rate.

[0004] In the existing technology, most of the limestone-gypsum wet desulfurization systems in the domestic electrolytic aluminum industry use traditional Roots blowers, which are fixed-volume types and cannot be adjusted in real time according to actual operating conditions, resulting in a large waste of energy. Summary of the invention

[0005] The object of the present invention is to provide an air conveying system and an air flow regulating method, which are used to solve the technical problem that the oxidation fan used in the limestone-gypsum wet desulfurization system in the prior art cannot adjust the air volume.

[0006] To achieve the above object, an embodiment of the present invention provides an air delivery system, including a fan with adjustable delivery volume, the fan is connected to a device for removing HSO3 in the slurry in the absorption tower slurry pool. - Oxidized to SO4 2-The absorption tower slurry pool is connected to a device for measuring HSO3 in the slurry in the absorption tower slurry pool. - The air delivery system also includes a control system connected with the fan and the sulfite analyzer.

[0007] One of the preferred solutions of the present invention is that the sulfite analyzer includes an analyzer body, which is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the absorption tower slurry pool through a pipeline, and a valve is provided on the pipeline. The liquid outlet is connected to a discharge pipe.

[0008] In one of the preferred solutions of the present invention, an anti-corrosion layer is provided inside the sulfite analyzer.

[0009] In one of the preferred solutions of the present invention, a flow meter is provided between the fan and the absorption tower slurry pool, and the flow meter is connected to the control system.

[0010] In one of the preferred solutions of the present invention, the fan is connected to the absorber slurry pool through a pipe-grid type pipeline, and the flow meter is located at one end of the pipe-grid type pipeline away from the absorber slurry pool.

[0011] In one of the preferred solutions of the present invention, the fan is an air suspension fan.

[0012] Based on an air delivery system disclosed in the present invention, the present invention also discloses an air flow adjustment method, comprising the following steps:

[0013] The control system calculates the oxidation air volume required for the absorption tower slurry pool by obtaining the flue gas volume at the absorption tower slurry pool inlet and the measured value of SO2 concentration, and adjusts the speed of the fan according to the calculated oxidation air volume.

[0014] In one of the preferred solutions of the present invention, the air flow regulation method further comprises the control system regulating the rotation speed of the fan by obtaining the sulfite analysis value of the absorption tower slurry pool.

[0015] In one of the preferred solutions of the present invention, the calculation formula for the oxidation air volume required for the absorption tower slurry pool is:

[0016]

[0017] Where Q is the oxidation air volume required for the absorber slurry pool, η is the desulfurization efficiency, γ is the flue gas flow rate, δ is the SO2 concentration, α is the natural oxidation rate, and β is the oxygen utilization rate.

[0018] In one of the preferred solutions of the present invention, the control system is preset with an alarm value, and when the slurry in the absorption tower slurry pool is insufficiently oxidized, the control system will sound an alarm.

[0019] In summary, the beneficial effects of the present invention are:

[0020] 1. The air delivery system of the present invention realizes the regulation of the delivery amount of the oxidation fan through the fan with adjustable delivery amount. At the same time, with the cooperation of the fan and the sulfite analyzer, the slurry in the absorption tower slurry pool is in the optimal oxidation reaction state, thereby improving the desulfurization efficiency and solving the problem that the oxidation fan used in the limestone-gypsum wet desulfurization system in the prior art cannot adjust the air volume.

[0021] 2. In the air flow regulation method of the present invention, the control system calculates the oxidation air volume required by the absorption tower slurry pool by obtaining the flue gas volume at the absorption tower slurry pool inlet and the measured value of SO2 concentration, and adjusts the speed of the fan according to the calculated oxidation air volume, thereby adjusting the air volume entering the absorption tower slurry pool, improving the real-time adjustability of the air delivery system, making the fan run at the optimal speed to provide a more appropriate oxidation air volume, thereby reducing the power consumption of the wet desulfurization process.

[0022] 3. The fan in the air delivery system of the present invention is an air suspension fan. The air suspension fan has a simple structure, without transmission devices such as a gear box and a coupling, and its efficiency is about 30% higher than that of a constant volume Roots blower.

[0023] 4. In the air delivery system of the present invention, a flow meter is provided between the fan and the absorber slurry pool, and the flow meter is connected to the control system. The flow meter is used to measure the amount of air delivered by the fan to the absorber slurry pool in real time, so as to facilitate the subsequent control system to accurately adjust the amount of air delivered by the fan, thereby providing further guarantee for the slurry in the absorber slurry pool to be in the best oxidation reaction state. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic structural diagram of an air delivery system according to an embodiment of the present invention.

[0025] Among them, 1-fan, 2-air filter sound absorber, 3-flow meter, 4-pipe grid pipeline, 5-absorption tower slurry pool, 6-control system, 7-sulfite analyzer. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0027] The present invention provides an air delivery system, such as Figure 1As shown, it includes a fan 1 with adjustable delivery volume, where the fan 1 is an air suspension fan. The air suspension fan has a simple structure, without a gear box, coupling and other transmission devices, and its efficiency is about 30% higher than that of the constant volume Roots fan 1. The fan 1 is connected to a device for removing HSO3 in the slurry in the absorption tower slurry pool 5. - Oxidized to SO4 2- The absorption tower slurry pool 5 is connected to a device for measuring HSO3 in the slurry in the absorption tower slurry pool 5. - The air delivery system also includes a control system 6 connected to the fan 1 and the sulfite analyzer 7. The control system 6 also has a real-time data display function, which can display the data in the air delivery system in real time for users to view.

[0028] The sulfite analyzer 7 can monitor the slurry in the oxidation reaction zone of the absorber slurry pool 5 online, and directly measure the sulfite (mainly calcium sulfite) ion concentration in the slurry using electrochemical principles. Its measurement range is 0-1000ppm, and the power input is 24VDC±15%, 9.6W, which is converted into a 4-20mA standard signal and uploaded to the above-mentioned control system 6 for real-time display. The sulfite analyzer 7 includes an analyzer body, and the analyzer body is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the absorber slurry pool 5 through a pipeline, and a valve is provided on the pipeline. The liquid outlet is connected to a discharge pipe, and the discharge pipe is connected to the trench; at the same time, an anti-corrosion layer is also provided inside the sulfite analyzer 7, and the anti-corrosion layer is provided to prevent the sulfite analyzer 7 from being corroded by the slurry, thereby extending the service life of the sulfite analyzer 7; the sulfite analyzer 7 is also equipped with a grounding wire to ensure reliable grounding.

[0029] A flow meter 3 is provided between the fan 1 and the absorption tower slurry pool 5, and the flow meter 3 is connected to the control system 6. The flow meter 3 is located at the air outlet of the fan 1, and is used to measure the amount of air delivered by the fan 1 to the absorption tower slurry pool 5 in real time, so that the subsequent control system 6 can accurately adjust the amount of air delivered by the fan 1, thereby providing further guarantee for the slurry in the absorption tower slurry pool 5 to be in the optimal oxidation reaction state. When adjusting the air delivery amount of the fan 1, the rotation speed of the fan 1 is adjusted by the value displayed on the flow meter 3, thereby adjusting the air delivery amount of the fan 1. An air inlet is provided at one end of the fan 1 away from the flow meter 3, and air enters the fan 1 through the air inlet, and an air filter absorber 2 is also provided between the fan 1 and the air inlet. The air filter absorber 2 is provided to filter impurities in part of the air, thereby protecting the fan 1.

[0030] The fan 1 is connected to the absorber slurry pool 5 through the tube-grid pipe 4, and the flow meter 3 is located at one end of the tube-grid pipe 4 away from the absorber slurry pool 5. The fan 1 conveys the air entering from the air inlet to the absorber slurry pool 5 through the tube-grid pipe 4.

[0031] Working process: The fan 1 transports the air entering from the air inlet to the absorption tower slurry pool 5 through the pipe grid pipe 4. The slurry in the absorption tower slurry pool 5 removes HSO3 in the slurry under the action of air. - Oxidized to SO4 2- At the same time, the sulfite analyzer 7 connected to the absorption tower slurry pool 5 measures the sulfite ion concentration in the slurry in the absorption tower slurry pool 5 in real time, and feeds back the measurement result to the control system 6. The control system 6 adjusts the speed of the fan 1 in real time according to the measurement result of the sulfite analyzer 7, thereby adjusting the amount of air delivered by the fan 1 to the absorption tower slurry pool 5, so that the slurry in the absorption tower slurry pool 5 is in the best oxidation reaction state.

[0032] Based on an air delivery system, the present invention also provides an air flow regulation method, comprising the following steps:

[0033] The control system 6 calculates the oxidation air volume required by the absorption tower slurry pool 5 by obtaining the flue gas volume at the inlet of the absorption tower slurry pool 5 and the measured value of SO2 concentration, and adjusts the rotation speed of the fan 1 according to the calculated oxidation air volume; specifically, the control system 6 calculates the oxidation air volume required by the absorption tower slurry pool 5 by obtaining the flue gas volume at the inlet of the absorption tower slurry pool 5 and the measured value of SO2 concentration, and adjusts the rotation speed of the fan 1 according to the calculated oxidation air volume, so that the data displayed on the flow meter 3 connected to the fan 1 meets the calculated oxidation air volume;

[0034] Further, the air flow regulation method also includes the control system 6 adjusting the speed of the fan 1 by the obtained sulfite analysis value of the absorber slurry pool 5; specifically, the air flow regulation method also includes the control system 6 adjusting the speed of the fan 1 by the obtained sulfite analysis value of the absorber slurry pool 5, so that the slurry in the absorber slurry pool 5 is in the best oxidation reaction state, thereby improving the desulfurization efficiency;

[0035] Furthermore, the control system 6 is also preset with an alarm value. When the slurry in the absorber slurry pool 5 is insufficiently oxidized, the control system 6 will sound an alarm to increase the speed of the fan 1 to prevent slurry poisoning and excessive SO2 emissions;

[0036] Since the limestone-gypsum wet desulfurization oxidation reaction equation is:

[0037] HSO3 - +1 / 2O2→SO4 2- +H +

[0038] SO3 2- +1 / 2O2→SO4 2- ;

[0039] From the above oxidation reaction equation of sulfite ions, it can be concluded that 0.5 mol of oxygen is required for every 1 mol of sulfite ions consumed. After considering various influencing factors, the calculation formula for the oxidation air volume required by the system can be derived through the flue gas flow rate, the mass concentration of SO2 in the flue gas and the oxidation air utilization rate:

[0040]

[0041] Where Q is the oxidation air volume required for the absorber slurry pool, η is the desulfurization efficiency, γ is the flue gas flow rate, δ is the SO2 concentration, α is the natural oxidation rate, and β is the oxygen utilization rate.

[0042] In summary, the air delivery system of the present invention realizes real-time monitoring and regulation of the oxidation stage, and the slurry in the desulfurization absorption tower always operates in the optimal oxidation state. Compared with the original Roots blower of the same power, the power saving rate is 28.9%.

[0043] Although the specific implementation of the present invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An air delivery system, characterized in that: The blower comprises a blower with adjustable delivery volume, the blower is connected to a blower for removing HSO3 in the slurry in the absorber slurry pool. - Oxidized to SO4 2- The absorption tower slurry pool is connected to a device for measuring HSO3 in the slurry in the absorption tower slurry pool. - The air delivery system also includes a control system connected to the fan and the sulfite analyzer.

2. An air delivery system according to claim 1, characterized in that: The sulfite analyzer comprises an analyzer body, on which a liquid inlet and a liquid outlet are arranged, the liquid inlet is connected to the absorption tower slurry pool through a pipeline, and a valve is arranged on the pipeline, and the liquid outlet is connected to a discharge pipe.

3. An air delivery system according to claim 1 or 2, characterized in that: An anti-corrosion layer is arranged inside the sulfite analyzer.

4. An air delivery system according to claim 1, characterized in that: A flow meter is arranged between the fan and the absorption tower slurry pool, and the flow meter is connected to the control system.

5. An air delivery system according to claim 4, characterized in that: The fan is connected to the absorber slurry pool through a pipe-grid type pipeline, and the flow meter is located at one end of the pipe-grid type pipeline away from the absorber slurry pool.

6. An air delivery system according to claim 1, characterized in that: The fan is an air suspension fan.

7. An air flow regulation method for an air delivery system according to any one of claims 1 to 6, characterized in that: The following steps are involved: The control system calculates the oxidation air volume required for the absorption tower slurry pool by obtaining the flue gas volume at the absorption tower slurry pool inlet and the measured value of SO2 concentration, and adjusts the speed of the fan according to the calculated oxidation air volume.

8. An air flow regulation method as claimed in claim 7, characterized in that: The air flow regulation method also includes a control system regulating the rotation speed of the fan by obtaining the sulfite analysis value of the absorption tower slurry pool.

9. The air flow regulating method according to claim 7, characterized in that: The calculation formula for the oxidation air volume required by the absorption tower slurry pool is: Where Q is the oxidation air volume required for the absorber slurry pool, η is the desulfurization efficiency, γ is the flue gas flow rate, δ is the SO2 concentration, α is the natural oxidation rate, and β is the oxygen utilization rate.

10. The air flow regulating method according to claim 7, characterized in that: The control system is preset with an alarm value, and when the slurry in the absorption tower slurry pool is insufficiently oxidized, the control system will sound an alarm.

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