Fractal bubble generating device for enhancing sulfuric acid tail gas absorption

Abstract

The utility model discloses a fractal bubble generating device for strengthening sulfuric acid tail gas absorption, and relates to the technical field of fractal bubble generating devices, the side wall of the device is provided with a radial liquid phase inlet, the bottom end of the device is provided with an axial gas phase inlet, and the device is provided with a throat pipe which is communicated with the liquid phase inlet and the gas phase inlet and has a certain length. A throat pipe through hole is formed in the throat pipe along the axial center of the throat pipe, an annular cutting channel with the height smaller than that of the throat pipe through hole is formed in the throat pipe in an annular cutting mode with the axial center of the throat pipe through hole as the center, a cylindrical body with the height consistent with that of the annular cutting channel is obtained, and radial conical through holes which are evenly distributed are formed around the cylindrical body in the annular direction. The conical through hole is opposite to the liquid phase inlet, and the liquid phase inlet, the girdling channel, the conical through hole and the throat pipe through hole are communicated. The device disclosed by the utility model has the effect of improving the SO2 absorption efficiency so as to reduce the alkali consumption.

Description

Technical Field

[0001] The utility model relates to the technical field of fractal bubble generating devices, and more specifically, to a fractal bubble generating device for strengthening the absorption of sulfuric acid tail gas. Background Art

[0002] With the continuous improvement of economic and industrial levels, SO 2 The emission volume also shows an increasing trend. The large-scale emission of sulfur dioxide gas has led to the intensification of acid rain, which will not only cause serious harm to the natural environment, but also have a direct impact on human health. If it cannot be effectively treated, it will aggravate the acidification of soil and water bodies, destroy the ecological balance, and affect biodiversity. With the enhancement of environmental awareness and the popularization of environmental protection laws and regulations, most of my country's sulfuric acid companies have increased their investment in sulfuric acid tail gas treatment. Relevant companies should comprehensively consider economic issues such as technical maturity, the source of desulfurizers, the outlet of by-products, and investment and operating costs, and choose a suitable tail gas desulfurization plan. At present, there are an estimated 200 flue gas desulfurization technologies being researched, developed and commercially applied in countries around the world.

[0003] According to the dry and wet forms of the desulfurization products, flue gas desulfurization can be divided into three processes: wet, semi-dry and dry. Among them, semi-dry and dry desulfurization processes are mainly aimed at power plant desulfurization. The wet flue gas desulfurization technology is the most mature, most practically applied and most stable desulfurization process among the desulfurization methods. The wet flue gas desulfurization process is a gas-liquid reaction. Its desulfurization reaction speed is fast and the desulfurization efficiency is high. It can reach a desulfurization efficiency of more than 90%, which is suitable for flue gas desulfurization in large coal-fired boiler chemical plants. In the wet flue gas desulfurization process, the desulfurization tower is the key equipment of the entire desulfurization system. In industry, there are many forms of desulfurization towers, such as packed towers, liquid column towers, spray towers, bubbling towers, etc. Among them, the spray tower, packed tower, jet bubbling tower and other technologies have problems such as large resistance loss, high requirements for desulfurizer particle size, scaling and clogging, large back mixing inside the liquid phase, large system resistance and large footprint. The liquid column tower has the characteristics of simple structure, large gas-liquid contact area, few circulating pumps and high desulfurization efficiency. For high-concentration sulfur-containing flue gas, a parallel-current and countercurrent liquid column tower can be used to obtain a high desulfurization rate and high dust removal effect. The absorption tower can be made into a square shape, which is convenient for arranging the spraying pipe, and is also convenient for maintenance and construction.

[0004] Schematic diagram of liquid column jet absorption tower Figure 1As shown in the figure, the waste gas enters from the gas-phase inlet 200 at the top of the absorption tower 100. Near the liquid-phase inlet 300 in the tower, there are several nozzles 400. The absorption liquid (alkali solution) enters the tower from the liquid-phase inlet 300 and through the nozzles 400. The absorption liquid in the packed column forms a fountain shape. Each nozzle 400 forms a liquid column, which is ejected upward and then falls in an umbrella shape from top to bottom. The speed at the top of the liquid column is zero. The waste gas enters the tower and collides with the upward-sprayed liquid droplets. The gas-liquid collision area is the absorption zone 500. The falling liquid droplets collide with the upward liquid droplets to form finer liquid droplets, thus increasing the gas-liquid contact. When the absorption liquid is sprayed upward, a turbulent flow is formed, accelerating the absorption of SO 2 The soot is strongly impacted and washed, and the dust removal and desulfurization effects are relatively high.

[0005] At present, an important factor restricting the operation cost of enterprises is the high alkali consumption cost, and the on-site demand of enterprises for reducing the alkali consumption cost is relatively high. And the packed column consumes the most alkali consumption, and this part of the alkali consumption is used to absorb SO 2 . That is to say, in order to reduce the alkali consumption, it is necessary to consider how to improve the absorption efficiency of SO 2 . Utility Model Content

[0006] Aiming at this problem in practical applications, the purpose of the present utility model is to propose a fractal bubble generating device starting from increasing the gas-liquid contact area to replace the nozzles of the original traditional packed column, and to strengthen the absorption of sulfuric acid tail gas by increasing the absorption liquid film area in the absorption zone, so as to improve the absorption efficiency and thus reduce the alkali consumption. The specific scheme is as follows:

[0007] A fractal bubble generating device for strengthening the absorption of sulfuric acid tail gas, the side wall of the device is provided with a radial liquid-phase inlet, and the bottom end is provided with an axial gas-phase inlet. A throat pipe with a certain length connecting the liquid-phase inlet and the gas-phase inlet is arranged on the device. A throat pipe through hole is axially opened in the center of the throat pipe along its axis. A circumferential cutting channel with a height less than the throat pipe through hole is formed by circumferential cutting in the throat pipe around the axial center of the throat pipe through hole, and a columnar body with a height consistent with the height of the circumferential cutting channel is obtained. Radial conical through holes are uniformly distributed in the circumferential direction around the columnar body, and the conical through holes are opposite to the liquid-phase inlet, wherein the liquid-phase inlet, the circumferential cutting channel, the conical through holes and the throat pipe through hole are connected and communicated.

[0008] Further, the device adopts a Venturi tube, the Venturi tube has a diffuser section, a throat section and a converging section connected in sequence from top to bottom. The diameter of the throat section is the narrowest diameter of the Venturi tube, and the ratio of the diameter of the throat section to the length of the throat section is 1:10. Channels are arranged inside the diffuser section and the converging section along their axes. The throat pipe through hole is connected and communicated with the channels inside the diffuser section and the converging section.

[0009] Further, the liquid phase inlet is a cylinder with a through hole opened along its axial center. The liquid phase inlet is arranged on the outer side wall of the throat pipe. The cylindrical liquid phase inlet with a through hole inside is tangent to the cylindrical throat pipe so that the axis of the liquid phase inlet is perpendicular to the axis of the throat pipe. The liquid phase inlet faces the circumferential cutting channel. When viewed from the front of the liquid phase inlet, the connection between the liquid phase inlet and the circumferential cutting channel is a rectangular groove, and the width of the rectangular groove is the same as the height of the circumferential cutting channel or the columnar body. Liquid enters through the liquid phase inlet, passes through the rectangular groove and the circumferential cutting channel, enters the conical through hole, and after a period of acceleration, enters the throat pipe through hole.

[0010] Further, the diameter of the circular cross-section of the conical through hole at the end facing the throat pipe is smaller than the diameter of the circular cross-section at the end close to the liquid phase inlet, which is a tapered conical hole; wherein, the ratio of the diameter of the large conical hole to the diameter of the small conical hole is 1:0.8.

[0011] The sizes of the conical through holes uniformly distributed around the columnar body are the same. The conical through holes in the same cross-section are called a group of conical through holes. The device includes 1 group or 2 groups of conical through holes; the number of conical through holes in each group is 4 or 6.

[0012] In the same group of the conical through holes, the central axis of the conical through hole is perpendicular to the central axis of the columnar body; when the number of the conical through holes is 2 groups, the positions of the two groups of conical through holes are symmetrically distributed with the center point of the height of the columnar body as the center, and the central axes of the conical holes between the two groups of conical through holes are aligned one by one.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0014] (1) Aiming at the problem of insufficient absorption mass transfer, fractal bubbles that can promote efficient mass transfer and efficient droplet dispersion are introduced into the liquid column injection pipe: Based on the existing conditions of the circulating pump of the caustic scrubbing system and the process characteristics of the injection pipe, through the development of the injection pipe structure, a certain amount of air or tail gas bubbles are injected into the injection liquid column; firstly, the bubbles increase the mass transfer area and strengthen the interfacial diffusion in the injection liquid column. In addition, the rupture of the bubbles at the gas-liquid interface of the liquid column will continuously generate thin film interfaces at different height positions of the entire liquid column; the thin film interfaces and the generated micro-droplets will provide a huge absorption surface area, realizing the SO absorption with the concentration gradient matching in the bottom space of the lower spray pipe and the liquid column tower, improving the SO absorption efficiency, and thus reducing the caustic consumption; 2 absorption, improving the SO 2 absorption efficiency, thereby reducing the caustic consumption;

[0015] (2) The fractal bubble generating device is small in volume and easy to replace. To improve the absorption efficiency of the liquid column tower, there is no need to replace large devices, reducing the cost of enterprises. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of a liquid column injection absorption tower in the prior art;

[0017] Figure 2 Schematic diagram of the liquid column spray absorption tower in the present utility model;

[0018] Figure 3 Schematic three - dimensional structure diagram of the present utility model;

[0019] Figure 4 Front view of the present utility model;

[0020] Figure 5 For the present utility model Figure 4 Cross - sectional view at A - A in;

[0021] Figure 6 Side view of the present utility model;

[0022] Figure 7 For the present utility model Figure 6 Cross - sectional view at B - B in;

[0023] Figure 8 Schematic diagram of the SO 2 absorption efficiency varying with the liquid volume in Test Example 1 of the present utility model.

[0024] Reference numerals: 100, absorption tower; 200, gas phase inlet; 300, liquid phase inlet; 400, nozzle; 500, absorption zone;

[0025] 1, expansion section; 2, throat; 3, contraction section; 4, throat through - hole; 5, liquid phase inlet; 6, gas phase inlet; 7, circumferential cutting channel; 8, columnar body; 9, rectangular groove; 10, conical through - hole. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. It should be understood that the following embodiments are only used to further illustrate the present utility model and should not be construed as limiting the protection scope of the present utility model. Some non - essential improvements and adjustments made by those skilled in the art based on the content of the present utility model still fall within the protection scope of the present utility model.

[0027] Embodiment 1

[0028] A fractal bubble generating device for enhancing the absorption of sulfuric acid tail gas, the device structure is as Figure 2-7 shown. Using the fractal bubble generating device in this application to absorb sulfuric acid tail gas to replace the traditional nozzle, see Figure 2 . The fractal bubble generating device blows air into the device from the gas phase inlet 6 through an air compressor, and the reaction alkali liquid enters the fractal bubble generating device from the liquid phase inlet 5. The two are mixed in the mixing chamber at the throat 2 and then sprayed out from the upper end of the device.

[0029] Specifically, the fractal bubble generating device adopts a Venturi tube, which has a diffuser section 1, a throat 2, and a converging section 3 connected in sequence from top to bottom. Preferably, the throat 2 is a cylinder, and the diameter of the throat 2 is the diameter of the narrowest part of the Venturi tube. The ratio of the diameter of the throat 2 to the length of the throat 2 is 1:10.

[0030] The diffuser section 1 and the converging section 3 are both internally provided with channels (not shown in the figure) along their axial directions. A throat through-hole 4 is axially opened in the center of the throat 2 along its axial direction, and the throat through-hole 4 is communicated with the channels in the diffuser section 1 and the converging section 3.

[0031] A radial liquid inlet 5 is provided on the side wall of the throat 2, and an axial gas inlet 6 is provided at the bottom end of the converging section 3. The throat 2 communicates the liquid inlet 5 and the gas inlet 6. Among them, the liquid inlet 5 is a cylinder axially provided with a through-hole in the center. The liquid inlet 5 is arranged on the outer side wall of the throat 2, and the cylindrical liquid inlet 5 with an internal through-hole is tangent to the cylindrical throat 2 so that the axis of the liquid inlet 5 is perpendicular to the axis of the throat 2.

[0032] A circumferential cutting channel 7 with a height less than that of the throat through-hole 4 is formed by circumferential cutting inside the throat 2 with the axial center of the throat through-hole 4 as the center, and a column 8 with a height consistent with that of the circumferential cutting channel 7 is obtained. Moreover, the height center points of the circumferential cutting channel 7 and the column 8 are consistent with the height center point of the throat through-hole 4. Preferably, the column 8 is a cylinder, and the circumferential cutting channel 7 is a circular ring channel. It should be noted that the column 8 can also be a regular polygon column, etc., and the circumferential cutting channel 7 can also be a regular polygon channel, etc., and no limitation is made thereto here.

[0033] The liquid inlet 5 faces the circumferential cutting channel 7. When viewed from the front of the liquid inlet 5, the connection between the liquid inlet 5 and the circumferential cutting channel 7 is a rectangular groove 9, and the width of the rectangular groove 9 is consistent with the height of the circumferential cutting channel 7 or the column 8.

[0034] Radial conical through-holes 10 are evenly distributed in the circumferential direction around the column 8. The conical through-holes 10 are opposite to the liquid inlet 5, and among them, the liquid inlet 5, the circumferential cutting channel 7, the conical through-holes 10, and the throat through-hole 4 are communicated. The liquid enters through the liquid inlet 5, enters the conical through-holes 10 through the rectangular groove 9 and the circumferential cutting channel 7, and then enters the throat through-hole 4 after a period of acceleration.

[0035] During operation, gas such as air or tail gas is injected into the device from the gas inlet 6, and liquid for reaction such as lye is injected into the device from the liquid inlet 5. The gas enters from the gas inlet 6 and passes through the converging section 3 to reach the throat 2, forming an upward flow. The liquid phase enters through the liquid inlet 5, enters the conical through-holes 10 through the circumferential cutting channel 7 and reaches the throat 2. The gas and the liquid are mixed at the mixing cavity of the throat through-hole 4 inside the throat 2, and then the liquid flows out of the fractal bubble generating device along with the gas flow, collides with the waste gas at a certain height of the nozzle to achieve convective absorption, and the absorbed sewage falls freely.

[0036] In the above process, gas enters the device to form bubbles. The bubbles increase the mass transfer area and strengthen the interfacial diffusion in the injection liquid column of the device. In addition, the rupture of the bubbles in the injection liquid column will continuously generate thin film interfaces at different height positions of the entire liquid column. The thin film interfaces and the generated micro-droplets will provide a huge absorption surface area to achieve the SO absorption with a concentration gradient matching in the bottom space of the lower spray pipe and the empty column of the liquid column. 2 In addition, the liquid is accelerated through the conical through-hole 10. The accelerated liquid phase collides with the gas in the throat through-hole 4 and is ejected from the device together with the gas. The ejected high-speed liquid column impacts the baffle in the absorption tower to generate a large number of tiny droplets, increasing the gas-liquid contact area and causing turbulence in the flow field in the tower, further promoting the absorption of SO. 2 Absorption.

[0037] When using the fractal bubble generating device, the absorption efficiency will be increased by about 3 - 7%, which is specifically determined according to the actual liquid column tower, working environment and the processing accuracy of the fractal bubble generating device.

[0038] Furthermore, the diameter of the circular cross-section of the conical through-hole 10 at the end facing the throat 2 is smaller than the diameter of the circular cross-section at the end close to the liquid phase inlet 5, which is a tapered conical hole; among them, the ratio of the diameter of the large conical hole to the small conical hole is 1:0.8.

[0039] The sizes of the respective conical through-holes 10 uniformly distributed around the columnar body 8 are the same. The conical through-holes 10 in the same cross-section are called a group of conical through-holes. The device includes 1 group or 2 groups of conical through-holes; the number of conical through-holes 10 in each group is 4 or 6.

[0040] In the same group of conical through-holes, the central axis of the conical through-hole 10 is perpendicular to the central axis of the columnar body 8; when the number of conical through-holes 10 is 2 groups, the positions of the two groups of conical through-holes are symmetrically distributed with the center point of the height of the columnar body 8 as the center, and the central axes of the conical holes between the two groups of conical through-holes are aligned one by one.

[0041] Test Example 1

[0042] The main equipment of the experimental device for the experiment includes 1 variable-frequency fan, 1 bottle of SO gas cylinder (equipped with a sulfur dioxide pressure reducing valve), 1 gas flowmeter, 2 SO sensors, 1 liquid flowmeter, 1 centrifugal pump, 1 8mm ordinary spray pipe, and several fractal internal parts. The main functional parameters of the device are shown in Table 1. 2 1 bottle of gas cylinder, 1 gas flowmeter, 2 SO sensors, 1 liquid flowmeter, 1 centrifugal pump, 1 8mm ordinary spray pipe, and several fractal internal parts. The main functional parameters of the device are shown in Table 1. 2 During the test process, the system operation from left to right is as follows:

[0043]

[0044] Table 1

[0045] During the test process, the system operation from left to right is as follows:

[0046] 1. The fan sucks air into the device through negative pressure;

[0047] 2. The gas flow regulating valve controls the sulfur dioxide concentration;

[0048] 3. The sulfur dioxide gas mixes with air at the inlet and then enters the absorption tower from the upper part;

[0049] 4. The absorption tower is made of plexiglass and consists of two parts: a reverse spray pipe and a liquid storage tank;

[0050] 5. A Venturi ejector is installed at the lower part of the reverse spray pipe, and the sprayed absorption liquid reacts with SO 2 ;

[0051] 6. The reacted gas is discharged from the upper part of the liquid storage tank;

[0052] 7. The absorption liquid in the liquid storage tank circulates and reacts under the action of a centrifugal pump;

[0053] 8. Sulfur dioxide sensors are installed at the tail gas inlet and outlet respectively to measure the absorption efficiency of sulfur dioxide.

[0054] Among them, the gas flow rate and the liquid flow rate are 200 m 3 / h and 1 - 2 m 3 / h respectively, and this value is scaled down in proportion to simulate the actual working conditions. The absorption liquid used in the experiment is a NaHSO 3 solution with a mass concentration of 15%, and sodium hydroxide is added to adjust the pH. The tail gas concentration is the same as the tail gas SO 2 concentration in the actual process flow, which is 1500 mg / m 3 (570 ppm), and the air volume of the fan is 200 m 3 / h. During the experiment, the absorption liquid flow rate is adjusted to 1 m 3 / h, 1.5 m 3 / h, and 2 m 3 / h respectively.

[0055] According to the above conditions, the SO 2 absorption performance of the spray pipe and the fractal internals is tested under three conditions of pH being 6, 7, and 8 respectively. The experimental results are obtained from the experiment. It can be seen from the experimental results that under the same conditions, the absorption effect of the fractal internals is better than that of the spray pipe. Figure 8 Figure shows the spraying effect diagrams of the two internals under different liquid volumes. At low liquid volume (1 m 3 / h), the liquid column spraying heights of the two internals are about 1 m. At this time, the fractal internals are better than the spray pipe because the fractal internals will self - absorb to generate fractal bubbles. When these bubbles coalesce and burst, it will increase the liquid film absorption area and at the same time cause disturbance to the air flow, thereby improving the absorption efficiency of SO 2 . At high liquid volume (2 m 3 / h), mainly because a large number of tiny droplets are generated when the high-speed liquid column impacts the baffle, increasing the gas-liquid contact area and causing turbulence in the tower internal flow field, thereby promoting the absorption of SO 2 .

[0056] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A fractal bubble generating device for strengthening the absorption of sulfuric acid tail gas, characterized in that: The device has a radial liquid inlet on its side wall and an axial gas inlet on its bottom end. The device has a throat of a certain length connecting the liquid inlet and the gas inlet. A throat through hole is provided in the throat along its axial center. An annular channel with a height less than the throat through hole is formed by circumferential cutting in the throat with the axial center of the throat through hole as the center, and a columnar body with a height consistent with the height of the annular channel is obtained. Uniformly distributed radial conical through holes are provided in the annular direction around the columnar body, and the conical through hole is opposite to the liquid inlet, wherein the liquid inlet, the annular channel, the conical through hole and the throat through hole are connected.

2. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 1, characterized in that: The device adopts a venturi tube, which has an expansion section, a throat and a tapered section connected in sequence from top to bottom. The diameter of the throat is the diameter of the narrowest part of the venturi tube, the ratio of the throat diameter to the throat length is 1:10, and the throat through hole is connected to the expansion section and the channel inside the tapered section.

3. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 1 or 2, characterized in that, The liquid phase inlet is arranged on the outer side wall of the throat and is perpendicular to the axis of the throat. The liquid phase inlet is opposite to the annular channel. When viewed from the front, the connection between the liquid phase inlet and the annular channel is a rectangular groove, and the width of the rectangular groove is consistent with the height of the annular channel or the columnar body.

4. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 3, characterized in that: The throat and the columnar body are both cylindrical, the liquid phase inlet is tangent to the cylinder of the throat, and the annular channel is an annular channel.

5. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 4, characterized in that: The conical through holes evenly distributed around the column have the same size, and the conical through holes on the same cross section are called a group of conical through holes. The device includes 1 or 2 groups of conical through holes; the number of conical through holes in each group is 4 or 6.

6. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 5, characterized in that: In the same group of the conical through holes, the central axis of the conical through holes is perpendicular to the central axis of the columnar body.

7. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 6, characterized in that: When the number of the conical through holes is 2, the positions of the two groups of conical through holes are symmetrically distributed with the center point of the columnar height as the center; and the two groups of conical through holes are aligned one by one with the central axes of the conical holes between the groups.

8. The fractal bubble generating device for strengthening sulfuric acid tail gas absorption according to claim 7, characterized in that: The diameter of the circular cross section of the conical through hole facing the throat is smaller than the diameter of the circular cross section of the end close to the liquid phase inlet, and it is a tapered conical hole; wherein the ratio of the diameter of the large conical hole to the small conical hole is 1:0.8.

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