CN101584957A - Integrated coupling device for flue gas desulfurization and dedusting - Google Patents

Abstract

An integrated coupling device for flue gas desulfurization and dust removal in the technical field of boiler flue gas desulfurization, comprising: a tower body, a tangential air inlet, a flue gas outlet, a bottom swirl plate, an inward spray plate, a spray layer, and a lower defogging plate And the upper mist eliminator, the central overflow pipe is located in the center of the inward spraying plate, and several spraying blades are fixed on the outer edge of the central overflowing pipe in an oblique and layer-by-layer manner in the form of a regular polygon. End fixed connection. The invention utilizes a uniquely designed inward jetting plate to organically couple spraying and swirling flow methods. The inward jetting plate has multiple functions of desulfurization and dust removal, improvement of air distribution and collection of desulfurization liquid, so that the invented device has high-efficiency desulfurization and dust removal. , and significantly reduce the liquid-gas ratio and airflow resistance.

Description

Flue gas desulfurization and dust removal integrated coupling device

technical field

The invention relates to a device in the technical field of boiler flue gas desulfurization, in particular to an integrated coupling device for flue gas desulfurization and dust removal.

Background technique

my country is the country with the largest coal consumption in the world, and the total amount of sulfur dioxide emitted by coal burning ranks first in the world. Therefore, the Chinese government is gradually implementing strict coal-fired flue gas emission standards, and implementing flue gas desulfurization and dust removal treatment for power plant boilers, industrial boilers and kilns.

There are various flue gas desulfurization methods. Currently, wet desulfurization devices widely used include bottom swirl plate tower, spray tower, bubble tower, Venturi absorber, etc.; large-scale thermal power desulfurization mostly uses spray tower, because of its gas path It has the least resistance and can adapt to different boiler loads, but it needs to adopt a higher liquid-gas ratio, and the dust removal effect is not ideal. The advantage of the bottom swirling plate tower is that it has high-efficiency dust removal and can achieve high efficiency at low liquid-to-gas ratio; but when the boiler load is low, the efficiency of the single plate is low and the desulfurization efficiency is not high enough. The combination of spray washing and swirl technology is beneficial to play the advantages of both.

After searching the existing technical literature, it was found that Zhang Guangxin's "Design and Application of 75t/h Boiler Flue Gas Desulfurization Device" (Metallurgical Power, 2003, 3: 637-639) modified the water film dust collector (Zhang Guangxin, 75t/h Design and application of boiler flue gas desulfurization device. Metallurgical Power, 2003, 3: 637-639), the spray section and the bottom swirl plate are respectively placed in two towers, so that the flue gas first flows in the spray tower gas-liquid After the contact, it is introduced into the bottom swirl plate column for gas-liquid countercurrent contact. However, this method is only a simple combination of the two, the process is long, multi-stage liquid supply is required, and the primary utilization rate of circulating liquid is low.

Patent application number: 200810120375, publication number CN101342455A, which records a "spray swirl combined desulfurization device", which divides the spray and bottom swirl plates into two sections in the same tower - the upper spray, the lower Swirling flow, the liquid inlet of the two stages is supplied by two sets of independent pumps. This kind of desulfurization device is relatively compact, and while ensuring the desulfurization efficiency, the airflow resistance can be significantly reduced. However, since the sprayed desulfurization liquid mostly flows along the tower wall to the overflow tank of the bottom swirl plate before reaching the lower bottom swirl plate, this part of the liquid cannot be used any longer, resulting in a relatively low primary utilization rate of the circulating liquid . At the same time, the flow field of the swirling upward airflow in the tower is unevenly distributed, which affects the spray washing effect.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides an integrated coupling device for flue gas desulfurization and dust removal, which uses an inward injection plate to organically combine swirling flow and spraying methods to form a new integrated desulfurization and dust removal device, thereby ensuring In the case of high-efficiency desulfurization and dust removal, the circulation volume of slurry is reduced, energy consumption is reduced, and the operating range is wider.

The present invention is achieved through the following technical solutions, the present invention includes: a tower body, a tangential air inlet, a flue gas outlet, a bottom swirl plate, an inward injection plate, a spray layer, a lower demister plate and an upper demister, Among them: the tangential air inlet is located on the side of the lower end of the tower body, the bottom swirl plate, the inward injection plate, the spray layer, the lower demister plate and the upper demister are arranged in parallel in the tower body from bottom to top, and the flue gas The outlet is located at the top of the tower body.

The swirl plate is located below the inward spray plate, and the special-shaped overflow pipe of the conventional swirl plate is removed, leaving a gap of 3-10mm between its outer edge and the tower wall;

The inward jetting plate is provided with: jetting blades, a central overflow pipe and a support rib, wherein: the central overflow pipe is located in the center of the inward jetting plate, and several jetting blades are fixedly arranged on the The outer edge of the central overflow pipe and the supporting rib are fixedly connected with the two ends of each spray blade.

The diameter of the central overflow pipe is 20%-40% of the diameter of the support plate.

The elevation angle between the spray blade and the horizontal plane is 20°～60°, so that the jet direction of the airflow points to the center; the width of the spray blade is 20～120mm, and the spray blade is made of whole plate cutting, sheet metal or multi-blade combination welding , according to the diameter of each plate, the number of sides of the regular polygon formed by the blades is 3-12.

The width of the support rib is 20-120mm;

The inward injection plate sprays the desulfurization liquid sprayed on the plate and the desulfurization liquid flowing down the tower wall inward again to achieve the effect of desulfurization and dust removal, and its desulfurization and dust removal efficiency of the single plate is close to that of the bottom swirl plate;

Compared with the prior art, the present invention utilizes the uniquely designed inward jetting plate to organically couple the spraying and swirling flow methods. The inward jetting plate has multiple functions of desulfurization and dust removal, improvement of air distribution and collection of desulfurization liquid, making the invention The device has high-efficiency desulfurization and dust removal, and significantly reduces the liquid-gas ratio and airflow resistance.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic diagram of the structure of the inward injection plate;

In the figure: a is the bottom view of the inward jetting plate; b is the side view of the inward jetting plate;

Among them: 1 tangential flue gas inlet, 2 tower body, 3 water film dust removal section, 4 bottom swirl plate, 5 inward spray plate, 6 spray layer and nozzle, 7 lower defogging plate, 8 spare spray pipe, 9 Upper demister, 10 flue gas outlet, 11 desulfurization liquid discharge outlet, 12 desulfurization circulation pump, 13 central overflow pipe (with water seal), 14 spray vanes and 15 support ribs.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

As shown in Figure 1, this embodiment includes: tangential flue gas inlet 1, tower body 2, water film dust removal section 3, bottom swirl plate 4, inward spray plate 5, spray layer and nozzle 6, lower defogging plate 7. Spare spray pipe 8, upper demister 9, flue gas outlet 10, desulfurization liquid discharge port 11 and desulfurization circulation pump 12, wherein: the tangential air inlet is located at the lower end side of the tower body, the bottom swirl plate, inward The injection plate, the spray layer, the first defogging plate and the second defogging plate are arranged in parallel in the tower body from bottom to top in sequence, and the flue gas outlet is located at the top of the tower body.

The special-shaped overflow pipe of the conventional swirl plate is removed from the bottom swirl plate, and a gap of 6mm is left between its outer edge and the tower wall.

As shown in Figure 2, the inward jetting plate 5 is provided with: a central overflow pipe 13, jetting blades 14 and support ribs 15, wherein: the central overflow pipe 13 is located at the center of the inward jetting plate 5, and 42 jetting The blades 14 are divided into 7 layers obliquely in a hexagonal manner, and are fixedly arranged on the outer edge of the central overflow pipe 13 layer by layer, and the supporting ribs 15 are fixedly connected to both ends of each spray blade 14 . The number of sides of the regular polygon formed by the leaves is 6.

The diameter of the central overflow pipe 13 is 30% of the diameter of the support rib 15 .

The elevation angle between the spray vane 14 and the horizontal plane is 30°, so that the jetting direction of the airflow points to the center; the width of the spray vane 14 is 100 mm, and the spray vane 14 is welded with multiple blades.

The width of described support rib 15 is 100mm;

The inward injection plate 5 sprays the desulfurization liquid sprayed on the plate and the desulfurization liquid flowing down the tower wall inward again to achieve the effect of desulfurization and dust removal, and its single plate desulfurization and dust removal efficiency is close to that of the bottom swirl plate 4;

This embodiment realizes flue gas desulfurization through the following process:

The flue gas containing soot and sulfur dioxide enters the absorption tower tangentially through the inlet flue 1, and performs pre-dust removal in the water film area 3 of the absorption tower. formed by the gap. Next, the air flow passes through the bottom swirl plate 4 at the bottom and sprays into contact with the liquid thin layer on the bottom swirl plate for desulfurization and dust removal. What flows to its blind plate is then sprayed and diffused around. Afterwards, the airflow continues to rise through the inward spraying plate 5, and sprays the desulfurization liquid layer on the plate inward, and continues desulfurization and dust removal during the spraying process. The desulfurization liquid on the inward injection plate mainly comes from the direct spraying with the spray layer and the liquid left along the tower wall. The desulfurization liquid is collected by the inward injection to the central overflow pipe and flows to the blind plate of the bottom swirl plate in the lower layer. Afterwards, the air flow passes through the spraying section and contacts with the desulfurization liquid droplets sprayed by the nozzles of the spray layer in countercurrent gas-liquid contact to continue the desulfurization process. After that, the flue gas passes through the lower defogging plate and the defogging plate to fully defog, and flows out of the absorption tower through the gas outlet. In the above process, the desulfurization liquid is transported to the spray layer by using a special desulfurization circulation pump.

The technical effect verification of this embodiment is as follows:

Using a test tower body with an inner diameter of 300 mm, it is combined into a spray and swirl integrated device as shown in Figure 1. The flue gas volume used in the test is 1000m ³ /h, the flue gas temperature is 90°C, the inlet flue gas SO ₂ concentration is 2600mg/Nm ³ , and the dust content is 1400mg/Nm ³ .

Remove the inward plate first, use only one spray layer and one bottom swirl plate, and supply desulfurization liquid to the tower through the spray layer, when the pH value of the liquid is 9 and the liquid-gas ratio is 2.0L/ ^m3 The measured desulfurization efficiency is about 82%, and the dust removal efficiency is 95%. The airflow resistance of the whole tower is only about 780Pa.

In the same situation, if the inward injection plate is placed between the bottom swirl plate and the spray layer, the desulfurization efficiency under similar conditions will be reduced to about 96%, and the airflow resistance of the whole tower will rise to about 900 Pa. It can be seen that the combination of the inward injection plate and the bottom swirl plate and spraying technology can significantly improve the purification degree of flue gas.

Example 2

For a coal-fired boiler with an evaporation capacity of 20t/h, the designed flue gas volume is 55000m ³ /h, the flue gas temperature is 150°C, the inlet flue gas SO ₂ concentration is 2200mg/Nm ³ , and the smoke dust content is 1200mg/Nm ³ . The device of the present invention adopts the device shown in Fig. 1 according to actual working conditions, and the inner diameter of the tower is 2200mm. Sodium-calcium double-alkali flue gas desulfurization process is adopted. The vane elevation angle of the bottom swirl plate is 28°, and the opening ratio is 32%; the elevation angle of the inward jet plate is 32°, and the opening ratio is 36%.

When the boiler load is 90%, and the liquid-gas ratio is 1.8L/m ³ , the measured desulfurization efficiency is 96.3%, and the dust removal efficiency is greater than 97% (the dust concentration of the outlet flue gas is lower than 50mg/Nm ³ ) . The airflow resistance of the whole tower is only about 800Pa.

Example 3 adopts the same structure as that of Example 1 to treat the coal-fired flue gas of a 40t/h coal-fired boiler. The flue gas is pre-dusted by a multi-tube dust collector, and then desulfurized and further dusted by a magnesium oxide desulfurization process. The flue gas volume to be treated is 120000m ³ /h, and the sulfur dioxide concentration is 3500mg/Nm ³ . The diameter of the absorption tower is 3500mm. The results show that when the liquid-gas ratio is 2.2L/m ³ , the desulfurization rate is 97%. No fouling and clogging occurred during the continuous operation of the equipment for 6 months.

Claims (8)

1, a kind of integrated coupling device for flue gas desulfurization and dedusting, comprise: tower body, the tangential admission mouth, exhanst gas outlet, bottom eddy flow plate, interior to jet tray, spraying layer, the first demist plate and the second demist plate, the tangential admission mouth is positioned at the lower end side of tower body, bottom eddy flow plate, interior to jet tray, spraying layer, the first demist plate and the second demist plate from bottom to top are set in parallel in tower body inside successively, exhanst gas outlet is positioned at the top of tower body, it is characterized in that: interiorly be provided with: eject blade to jet tray, center overflow pipe and gripper shoe muscle, wherein: the center overflow pipe is positioned at the central authorities to jet tray, some eject blades are with the oblique outer that successively is fixedly set in the center overflow pipe of polygon mode, and the gripper shoe muscle is fixedlyed connected with the two ends of each sheet eject blade.

2, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, described bottom eddy flow plate has been removed the special-shaped overflow pipe of conventional eddy flow plate, leaves the space of 3-10mm between its outer rim and the tower wall.

3, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, described interior diameter to the center of jet tray overflow pipe is 20%～40% of a gripper shoe muscle diameter.

4, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, is 20 °～60 ° to the eject blade of jet tray and the elevation angle that horizontal plane is in described.

5, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, is 20～120mm to the width of the eject blade of jet tray in described.

6, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, described interior eject blade to jet tray is made for whole plate cutting, panel beating or multiple-blade Combination Welding.

7, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, is 20～120mm to the width of the gripper shoe muscle of jet tray in described.

8, integrated coupling device for flue gas desulfurization and dedusting according to claim 1 is characterized in that, is 3-12 to the regular polygon limit number that the blade of jet tray is formed in described.

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