CN102198369A - Swirling inlet type electrostatic spraying wet flue gas desulphurization dedusting apparatus - Google Patents

Abstract

The invention relates to a swirling air intake type electrostatic spray wet flue gas desulfurization and dust removal device for exhaust gas purification, which includes a spray reaction tower, an electrostatic spray device, a demister, a flow controller, a control signal sensor, an induced draft fan, an exhaust gas inlet and Waste collection port. The electrostatic spray method of inductive charging and corona charging combined with ring electrodes and needle electrodes further refines the slurry droplets, makes the droplets charged and uncharged high-voltage polarized, and generates additional mass transfer driving force ; and the air intake adopts the swirling air intake method to increase the contact time between the flue gas and the mist droplets; the concentration online monitoring device is used to realize the automatic adjustment of the electrostatic voltage and the slurry flow rate to ensure that the desulfurization efficiency remains within a certain range. While meeting emission standards, enhance economic benefits. The flue gas desulfurization and dust removal efficiency involved in the invention is high, the liquid-gas ratio is reduced, the operation cost is low, and the price is moderate, so it is an ideal environmental protection equipment.

Description

A swirl air intake type electrostatic spray wet flue gas desulfurization and dust removal device

technical field

The invention relates to a flue gas desulfurization and dust removal device.

Background technique

Wet calcium flue gas desulfurization technology began in 1909, and the world's first lime flue gas desulfurization system was built in 1931. Since the 1960s, the United States, Japan, and Germany have successively carried out large-scale research work, and gradually implemented and improved flue gas desulfurization technology (FGD), of which wet flue gas desulfurization technology (WFGD) accounts for more than 85%. my country's flue gas desulfurization technology started relatively late, mainly by introducing more mature FGD technology from abroad, and gradually absorbing and realizing the localization of FGD technology. From a technical point of view, coal desulfurization can be controlled in three ways: pre-combustion, during combustion and post-combustion. The comprehensive application of the above three stages of desulfurization technology can completely solve the problem of SO ₂ pollution. For economic considerations, flue gas desulfurization technology (FGD) will play an important role. FGD is divided into dry method, semi-dry method and wet method, and calcium wet method flue gas desulfurization technology still occupies the dominant position. Dry methods mainly include furnace dry injection desulfurization method, high-energy electron activation oxidation method, charged dry powder injection desulfurization method (CDSI), and activated carbon absorption method. The most widely used semi-dry methods are rotary spray drying (SDA), flue gas circulating fluidized bed flue gas desulfurization technology (CFB-FGD), flue injection desulfurization technology and humidified ash desulfurization technology (NID). Wet desulfurization mainly includes the following processes, limestone-gypsum method, phosphorus-ammonia compound fertilizer method (PAFP) method, ammonia absorption method, seawater desulfurization method, double alkali method, magnesium oxide method, etc.

Wet flue gas desulfurization technology has the characteristics of good desulfurization effect, relatively simple process, high utilization of absorbent, and stable and reliable operation, so it is the most widely used. However, in the actual operation process, the liquid gas is relatively large, which causes a great waste of water resources, and the treatment of wastewater is extremely difficult, and the formation of acidic droplets causes great corrosion to the desulfurization equipment. In order to effectively improve the astonishing water consumption of wet flue gas desulfurization, the key point is to refine the desulfurizer slurry droplets to ensure that the total contact area between the flue gas and the slurry droplets remains unchanged when the liquid-gas ratio is reduced, which can Effectively improve the desulfurization effect and ensure that the mist will not form powder in the desulfurization process, but a slurry-like residue. At the same time, the wet flue gas desulfurization also has the function of dust removal.

There are similar products and technologies at home and abroad at present, but there are still many shortcomings. For example, the rotary charged spray semi-dry desulfurization device adopts the method of charging the droplets after rotary atomization to improve the dispersion degree of the droplets in space, so as to overcome the fine particles of alkaline droplets formed by the rotation of the high-speed rotary sprayer. It is easy to collide and condense into large particles of liquid droplets in the flue gas. This patent can effectively improve the atomization effect of the slurry, but it is unfavorable for the continuous and stable charging of the slurry. This patent adopts a new type of electrode, and adopts the combination of needle-shaped and ring-shaped electrodes to realize the stability and durability of the droplet charging process. And use the smoke concentration online monitoring and feedback system to control and adjust the slurry flow through the signal when the smoke concentration changes, so as to achieve the emission target, and make full use of the slurry to reduce the cost of energy saving and emission reduction.

Among the existing technologies retrieved, there are mainly Chinese patents with the application number of 200720006066 "rotary charged spray semi-dry desulfurization device" and "test of charged spray desulfurization" ([J]. Journal of Jiangsu University: Natural Science Edition, 2007, 28 (5)), "Charged Spray Desulfurization Experiment and Mechanism Analysis" ([J]. Journal of Environmental Science, 2001, 21 (5)) are relatively close to the present invention.

Contents of the invention

The purpose of the present invention is to provide a swirling air intake type electrostatic spray wet flue gas desulfurization device, especially an electrostatic spray wet flue gas desulfurization and dust removal system that can effectively control the emission of sulfur dioxide and dust in the waste gas and How to use it. It can overcome the shortcomings of high liquid-to-gas ratio, huge water consumption and uneven concentration of alkaline droplets during transportation in the wet flue gas desulfurization system. Under the action, an additional mass transfer driving force is generated, which enhances the ability of the mist to absorb SO ₂ and dust.

According to the above purpose, an electrostatic spray flue gas desulfurization and dust removal system is designed, including spray reaction tower, electrostatic spray device, mist eliminator, flow controller, control signal sensor, induced draft fan, waste gas inlet and waste collection port. The exhaust gas inlet is located at the bottom of the spray reaction tower. The shape of the exhaust gas inlet is rectangular, and 3-5 swirl baffles are evenly arranged in the horizontal direction within the rectangle, and the angle of the deflector is adjusted from 0 to 90 degrees. The electrostatic spraying device includes atomizing nozzles, high-voltage electrostatic generators, electrodes, interconnected pipelines and electrode power lines; the atomizing nozzles use low-pressure swirling atomizing nozzles, and a combination of ring electrodes and needle electrodes is arranged outside the atomizing nozzles The electrode assists the atomization of the spray area. The diameter of the ring electrode is 100-300mm, and the distance between the plane of the ring electrode and the plane of the nozzle bottom can be adjusted in the range of 0-100mm; the atomizing nozzle and the electrode are set on the upper part of the spray reaction tower, and the high-voltage electrostatic generator is located outside the spray reaction tower. The generator is connected to the nozzle and the ring electrode respectively through the pipeline and the electrode power line through the spray reaction tower body. The mist eliminator is located on the top of the spray reaction tower body. The mist eliminator is a double-layer mist eliminator, and the first layer is sparser than the second layer. The induced draft fan is connected with the outlet at the top of the spray reaction tower through a pipeline. The waste collection port is set at the bottom of the spray reaction tower. The flow controller is located outside the tower body of the spray reaction tower, the flow controller is connected with the atomizing nozzle through a pipeline, and the flow controller is provided with a slurry inlet. The control signal sensor is respectively connected to the flow controller and the high-voltage electrostatic generator, and the control signal sensor is connected to the concentration measuring device. Concentration Measuring Device Concentration measuring probes are respectively arranged at the exhaust gas inlet and the exhaust gas outlet. The control signal sensor adjusts the flow controller according to the signal provided by the concentration measuring device to adjust the flow rate of the slurry; the concentration measuring device detects the sulfur dioxide concentration and dust concentration at the inlet and outlet in real time, and calculates the desulfurization rate η ₁ and dust removal efficiency η ₂ , When the desulfurization rate η ₁ and dust removal efficiency η ₂ are not within the rated value range, a signal (slurry flow or voltage is effectively adjusted) will be sent to the high-voltage electrostatic generator or flow automatic adjustment device for adjustment through the control signal sensor, so that It meets the rated removal rate range of SO ₂ and dust.

In the present invention, under the action of the high-voltage electrostatic field, the particle size of the droplets in the slurry spray reactor is further reduced, and the degree of dispersion in the space is increased under the action of Coulomb repulsion, which effectively increases the contact area and effect of the droplets and the exhaust gas. time; in the present invention, the waste gas enters the reaction tower through the swirl device, forming a spiral air flow, which increases the effective action time of the mist and the waste gas; The extra force of flying dust improves the desulfurization and dust removal effect of fog droplets; under the action of high-voltage electric field, the distribution of ions in fog droplets will be significantly improved, which will be beneficial to the ionization of calcium-based ions in fog droplets, thereby improving the desulfurization efficiency . On the basis of previous studies, the present invention improves the traditional ring electrode and uses the electrode form combining ring and needle to ensure the stability and continuity of the droplet charging process and avoid the simple ring electrode charging in the spray area. of instability.

The on-line concentration monitoring and flow regulating device of the present invention achieves the discharge standard of waste gas while fully utilizing the slurry. Under the premise of energy saving and emission reduction, the desulfurization efficiency is similar to that of conventional wet flue gas desulfurization, but the liquid-gas ratio is 1/3 of that of conventional spraying method, which effectively saves water resources and protects the natural environment.

Description of drawings

Fig. 1 is a schematic diagram of the structure of an embodiment of the present invention.

Fig. 2 is a schematic diagram of the exhaust gas inlet cyclone device.

Figure 3 is the charging electrode (combination of ring and needle).

Figure 1, 1 spray reaction tower; 2 electrodes; 3 atomizing nozzle; 4 demister; 5 flow control valve; 6 slurry inlet; 7 high voltage electrostatic generator; 8 control signal sensor; ; 11 waste gas inlet; 12 waste collection port; 13 swirl baffle.

Detailed ways

When the patent of the present invention is in use, the exhaust gas (flue gas and dust) produced by coal combustion passes through the exhaust gas inlet 11, passes through the swirl baffle 13, and the swirl baffle can be adjusted according to the angle, rotates and flows into the spray reaction tower 1, and passes through the swirl baffle 13. The slurry inlet 6 flows through the flow control valve 5, sprayed out from the nozzle 3, and the mist droplets charged by the ring-shaped and needle-shaped charging electrode 2 remove SO ₂ and dust. After the mist is sprayed through the pressure nozzle, it will generate secondary atomization under the action of the charged electrode to form finer mist. Under the action of the high-voltage electrostatic field, it will chemically react with the mist to remove SO ₂ , and Remove dust from exhaust gas. When the ring and needle electrodes are used for charging, the charging effect of the ring electrodes on the droplets is inductive charging when the humidity of the droplets is low. The corona charging effect is generated, thereby overcoming the deficiency of a single charging method. The induced draft fan 9 provides the power for flue gas movement, and the concentration measuring device 10 obtains the desulfurization efficiency and dust removal rate by measuring the content of SO ₂ and dust in the inlet and outlet. The control signal sensor 8 controls the high-voltage electrostatic generator 7 and the flow controller 5 by sensing changes in desulfurization efficiency and dust removal rate. Example: when the concentration of _SO2 passing through the exhaust gas inlet 11 increases, the concentration detection device detects that the concentration difference between the inlet and outlet increases, and the desulfurization efficiency decreases. The generator 7 and the flow controller 5 transmit signals to increase the flow rate to increase the calcium-sulfur ratio and electrostatic voltage to increase the absorption efficiency of SO ₂ . When the desulfurization efficiency and dust removal rate meet the rated efficiency, the control signal sensor 8 stops working. When the concentration of _SO2 passing through the exhaust gas inlet 11 decreases, the concentration detection device detects that the concentration difference between the inlet and outlet decreases, and the desulfurization efficiency increases. When it is higher than a certain rated efficiency, in order to ensure the economy of the desulfurization system, the signal sensor is controlled. 8 starts to transmit signals to the high-voltage electrostatic generator 7 and flow controller 5 to reduce the flow rate to increase the calcium-sulfur ratio and electrostatic voltage to moderate the absorption efficiency of SO ₂ and make it work under rated conditions.

The demister is equipped with double layers, so that the mist droplets enter the power unit as little as possible without significantly increasing the resistance, so as to ensure that the device is not corroded by acid mist, and the stability and reliability of the operation of the device are guaranteed. The slag-containing waste liquid produced by desulfurization can be collected through the waste material collection port 12, and the residue is removed after precipitation, and the waste liquid can be recycled to improve the utilization rate of calcium.

Claims (4)

1. eddy flow air admission type electrostatic spray wet process of FGD dust arrester, it is characterized in that, comprise spraying reaction tower (1), electrostatic atomizer, demister (4), flow controller (5), control signal sensor (8), air-introduced machine (9), exhaust gas entrance (11) and garbage collection mouth (12); Described exhaust gas entrance (11) is positioned at the bottom of spraying reaction tower (1); Described electrostatic atomizer comprises atomizer (3), HV generator (7), electrode (2), interconnective pipeline and electrode power-line; Described atomizer adopts low pressure vortex atomizing nozzle (3), is furnished with electrode (2) outside the described atomizer (3) spraying area is carried out assisted atomization; Described annular electrode size diameter is 100-300mm, and described annular electrode plane and atomizer (3) base plane is apart from the 0-100mm range regulation; Described atomizer (3) and electrode (2) are arranged at the top in spraying reaction tower (1) tower body, described HV generator (7) is positioned at outside the spraying reaction tower (1), and HV generator (7) passes spraying reaction tower (1) body by pipeline and electrode power-line and links to each other with annular electrode with nozzle respectively; Described demister (4) is positioned at the top of spraying reaction tower (1) tower body, and described demister (4) is double-deck demister, and ground floor is more sparse than second layer grid; Described air-introduced machine (9) is connected by the outlet of pipeline with spraying reaction tower (1) cat head; Described garbage collection mouth (12) is arranged at the bottom of spraying reaction tower (1); Described flow controller (5) is positioned at spraying reaction tower (1) tower body outside, and described flow controller (5) is connected with atomizer (3) by pipeline, and described flow controller (5) is provided with slurries inlets (6); Described control signal sensor (8) is connection traffic controller (5) and HV generator (7) respectively.

2. a kind of eddy flow air admission type electrostatic spray wet process of FGD dust arrester according to claim 1, it is characterized in that, described exhaust gas entrance (11) is shaped as rectangle, evenly arrange 3-5 piece eddy flow baffle plate (13) in the rectangle in the horizontal direction, described eddy flow baffle plate (13) angle is regulated at the 0-90 degree.

3. eddy flow air admission type electrostatic spray wet process of FGD dust arrester according to claim 1 and 2, it is characterized in that, also comprise apparatus for measuring concentration (10), described control signal sensor (8) connects apparatus for measuring concentration (10), and described apparatus for measuring concentration (10) measurement of concetration probe is separately positioned on exhaust gas entrance (11) and waste gas outlet; Described control signal sensor (8) is regulated the flow of slurries according to the Signal Regulation flow controller (5) that apparatus for measuring concentration (10) provides.

4. eddy flow air admission type electrostatic spray wet process of FGD dust arrester according to claim 1, it is characterized in that, described electrode (2) combines with needle electrode for annular electrode, described annular electrode size diameter is 100-300mm, described annular electrode plane and nozzle bottom plan range 0-100mm range regulation.

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