CN201058277Y - Cross-flow double-cycle wet flue gas desulfurization device in the flue - Google Patents

Abstract

Cross-flow double-cycle wet flue gas desulfurization device in the flue, including flue, slurry tank, partition, air compressor, slurry pump, sprayer, masking angle, demister, feeding tank, evaporative cooling section, condensation discharge The hot section and circulation pump are characterized in that there is a slurry tank connected to the flue under the flue; the spray desulfurization is carried out in the flue, and the flue is equipped with a primary sprayer and a secondary sprayer. The circulation system enables the two-stage spraying to operate at different pH values; a cover angle is provided at the front end of the two-stage spraying device and the upper end of the middle flue, and a demister is provided at the rear of the secondary sprayer. The utility model has simple structure, low cost, can reduce system resistance, and is beneficial to improve system operation efficiency and desulfurization efficiency.

Description

Cross-flow double-cycle wet flue gas desulfurization device in the flue

1. Technical field

The utility model belongs to the field of industrial waste gas purification, environmental protection and energy, in particular to a cross-flow double-circulation wet flue gas desulfurization device in a flue gas duct for flue gas purification.

2. Background technology

Flue gas desulfurization is an effective method widely used at home and abroad to control SO ₂ in coal-fired flue gas. Among them, the wet flue gas desulfurization process is the most widely used and most effective flue gas desulfurization process in the world. However, the wet flue gas desulfurization process devices commonly used at present still have the following problems: (1) the flue gas is introduced from the flue to the desulfurization tower for desulfurization and then sent back to the flue, the system resistance increases greatly, and the system is complicated and the construction cost is high; (2) ) using a single cycle system, the dissolution of limestone, the oxidation of CaSO ₃ ·1/2H ₂ O and the absorption of SO ₂ cannot be operated under optimal reaction conditions. Because the pH value of the slurry in the wet desulfurization system not only affects the solubility of limestone, CaSO ₄ ·2H ₂ O and CaSO ₃ ·1/2H ₂ O, but also affects the absorption of SO ₂ . Low pH value is beneficial to the dissolution of limestone and oxidation of CaSO ₃ ·1/2H ₂ O, while high pH value is beneficial to SO ₂ absorption. It is difficult to solve this contradiction by single cycle.

Although many devices have been designed to overcome the above two problems at home and abroad, these devices can only overcome one of the problems at present, such as the U-shaped absorption zone advection absorption tower with domestic application number 200710019337.7 and other spraying technologies in the flue Or the device, although it can solve the problems of flue gas introduction and extraction, large system resistance, and high construction cost to a certain extent, it still adopts a single-cycle system, which cannot solve the problems caused by the above-mentioned single-cycle system; another example is the United States. Nuoer double-circulation wet flue gas desulfurization process and domestic application (patent) No. 200620200307.7 dual-circulation limestone/lime-gypsum wet flue gas desulfurization device, application (patent) No. 200610200285.9 dual-circulation limestone/lime-gypsum Although the wet flue gas desulfurization method uses a double-cycle system to solve the problems caused by the above-mentioned single-cycle system, these methods are complex and still need to introduce the flue gas into a large desulfurization tower and then return it, which cannot solve the problem of large system resistance, Problems such as high construction costs.

3. Contents of the invention

The utility model provides a cross-flow double-circulation wet flue gas desulfurization device in a flue, and its purpose is to solve the above-mentioned problems existing in the current wet flue gas desulfurization process device: the spray desulfurization is carried out in the flue, and the construction of a large desulfurization tower is cancelled. and the introduction and extraction of flue gas, only a slurry pool integrated with the flue is provided under the flue to reduce system resistance and construction costs. Dissolution of limestone, oxidation of CaSO ₃ 1/2H ₂ O and absorption of SO ₂ operate under their respective optimal conditions; cross-flow spraying is adopted in the flue, and diversion devices are installed in front and in the middle of each spraying section , to avoid the short-circuit phenomenon of flue gas in desulfurization, and improve the desulfurization efficiency; in addition, according to different situations, different forms of heating devices are installed in the flue gas to heat the flue gas after desulfurization.

The utility model is achieved through the following technical solutions:

A cross-flow double-cycle wet flue gas desulfurization device in the flue, including a flue, a slurry tank, a partition, an air compressor, a slurry pump, a sprayer, a masking angle, a demister, a feeding tank, an evaporative cooling section, Condensation and heat release section, circulation pump, characterized in that there is a slurry tank connected with the flue under the flue, a primary sprayer and a secondary sprayer are arranged in the flue, and the middle of the spraying devices at both ends The upper end of the flue is provided with a cover angle, and a demister is provided at the rear of the secondary sprayer; the above-mentioned slurry tank is divided into a primary slurry tank and a secondary slurry tank by a partition, and the lower end of the partition is provided with a Connecting door; the primary sprayer is connected to the primary slurry tank through the pipeline and the slurry circulating pump; the secondary sprayer is connected to the secondary slurry tank through the pipeline and the slurry circulating pump; the evaporative cooling section before the primary sprayer and the secondary The condensing and exothermic section behind the stage sprayer is respectively equipped with a series split heat pipe reheater, and a circulation pump is installed on the pipeline of the condensed liquid.

The above-mentioned cross-flow double-circulation wet flue gas desulfurization device in the flue uses flue spray desulfurization instead of spray desulfurization in the desulfurization tower, eliminating the construction of large desulfurization towers and the introduction of flue gas, effectively reducing system resistance and construction costs .

In the cross-flow double-circulation wet flue gas desulfurization device in the above-mentioned flue, the slurry tank is opened under the flue and integrated with the flue, and the construction cost is relatively low.

The above-mentioned cross-flow double-circulation wet flue gas desulfurization device in the flue, the spraying is divided into two sections, and the pH value of the slurry sprayed in the two sections is different. Extraction from the tank.

The cross-flow double-circulation wet flue gas desulfurization device in the above-mentioned flue, the two slurry tanks are separated by a partition, and the lower end of the partition is provided with a connecting door. The upper part of the partition is replenished by overflow; the lower part of the slurry tank is equipped with a stirring device.

The above-mentioned cross-flow double-circulation wet flue gas desulfurization device in the flue adopts the cross-flow spraying method, and at the same time, a cover angle diversion device is installed in front and in the middle of each spray section in the flue to avoid the short circuit of the flue gas in the desulfurization process. , so that the flue gas is in full contact with the slurry, which is more conducive to desulfurization.

The above-mentioned cross-flow double-circulation wet flue gas desulfurization device in the flue can use different reheating devices such as split heat pipe reheaters or external heat source reheaters to reheat the flue gas after desulfurization according to different actual conditions.

The utility model overcomes the problems of large system resistance, high cost, dissolution of limestone, oxidation of CaSO ₃ 1/2H ₂ O and absorption of SO ₂ for pH value difficult to coordinate and unify in the conventional wet desulfurization process. In the case of high efficiency, the flue gas is sprayed and desulfurized in two stages in the flue through two independent and connected slurry tanks integrated with the flue to provide slurry with different pH values, which can reduce system resistance. Reduce the cost, and at the same time make the dissolution of limestone, the oxidation of CaSO ₃ 1/2H ₂ O, and the absorption of SO ₂ be carried out at different pH values, which is conducive to improving the operating efficiency of the system; there are masking angle guides in front of each spray section in the flue The flow device avoids the short circuit phenomenon of the flue gas in the desulfurization process, and forms a cross-flow phenomenon locally, which is also conducive to improving the desulfurization efficiency; at the same time, the split heat pipe reheater and external heat source reheater are set according to the actual situation. The device is flexible in setting and simple in structure, which can ensure the discharge temperature requirements of flue gas after desulfurization.

Description of drawings

Figure 1 is a schematic diagram of a cross-flow double-cycle wet flue gas desulfurization device in the flue;

Figure 2 is a schematic diagram of a split heat pipe reheater.

Among them: 1. Primary slurry tank, 2. Partition plate, 3. Secondary slurry tank, 4. Connecting door, 5. Air compressor, 6. Slurry pump, 7. Slurry circulation pump, 8. Liquid return pump, 9 .First-level sprayer, 10. Covering angle, 11. Secondary sprayer, 12. Demister, 13. Slurry circulation pump, 14. Feeding tank, 15. Evaporative cooling section, 16. Condensation heat release section, 17. Circulation pump.

Detailed ways

Example:

The structure is shown in Figure 1 and Figure 2, consisting of a flue, a slurry tank, a partition 2, an air compressor 5, a slurry pump 6, a sprayer, a cover angle 10, a demister, a feeding tank 14, and an evaporative cooling section 15 , condensing heat release section 16, and circulation pump 17. It is characterized in that a slurry tank connected with the flue is provided under the flue, and a primary sprayer and a secondary sprayer are arranged in the flue. The upper end of the middle flue of the shower device is provided with a cover angle, and a demister is provided at the rear of the secondary sprayer; the above-mentioned slurry tank is divided into a primary slurry tank 1 and a secondary slurry tank 3 by a partition, The lower end of the partition 2 is provided with a connecting door 4; the primary sprinkler is connected to the primary slurry tank 1 through the pipeline and the slurry circulation pump 7; the secondary sprinkler 11 is connected to the secondary slurry tank 3 through the pipeline and the slurry circulation pump 13; The evaporative cooling section 15 before the primary sprayer 9 and the condensing heat release section 16 after the secondary sprayer 11 are respectively provided with series split heat pipe reheaters, and a circulation pump 17 is provided on the condensate pipeline. The first-level slurry tank 1 and the second-level slurry tank 3 are separated by a partition plate 2, and the bottom is connected through a communication door 4. The slurry in the first-level slurry tank 1 is supplied by the second-level slurry tank 3 through the communication door 4 or on the partition plate. 2 The upper part is completed by overflow, and most of the desulfurization products in the secondary slurry tank 3 also enter the primary slurry tank 1, so only the oxidation device needs to be installed in the primary slurry tank 1. The solid concentration of the slurry in the primary slurry tank 1 reaches more than 15%, and is introduced into the dehydration system for treatment, and the recycled water is returned to the secondary slurry tank 3 . The desulfurized flue gas is reheated by the reheater and then discharged. The reheater can use split heat pipe reheater, external heat source reheater and other reheaters according to the actual situation. Figure 2 shows the split heat pipe reheater. Heater, this split type heat pipe reheater is composed of evaporative cooling section 15, condensation heat release section 16 and circulation pump 17. The evaporative cooling section is located in front of the primary desulfurization area. After the hot flue gas passes through the evaporative cooling section 15, the liquid in the pipe evaporates and absorbs heat, and the temperature of the flue gas decreases, which is beneficial to desulfurization; the evaporated steam enters the condensation heat release section 16, and the condensation heat release section is located at After the secondary desulfurization area, after the desulfurized flue gas contacts it, the steam in the pipe condenses and releases heat, which increases the temperature of the flue gas and facilitates discharge. The condensed liquid returns to the evaporative cooling section 16 under the action of the circulation pump 17, and accordingly cycle. If it is convenient to introduce the external heat source, an external heat source type reheater can also be used and installed after the secondary desulfurization area.

The flue gas flows from left to right in the flue, and after entering the desulfurization area, the flow direction is adjusted by the set guide device, and then the first-stage desulfurization is carried out. At this time, the slurry is provided by the slurry tank 1 through the slurry circulation pump 7, and the pH value of the slurry is maintained between 4-5.5. After the flue gas is sprayed and desulfurized by the first-level sprayer 9, the flue gas flow mode is adjusted by the cover angle 10 to avoid the flue gas flowing away from the upper wall of the flue to cause a desulfurization short circuit and affect the desulfurization efficiency; most of the desulfurized products in this area Flow back to slurry tank 1 along the wall. The flue gas after flow adjustment enters the secondary desulfurization area. At this time, the slurry is provided by the secondary slurry tank 3 through the slurry circulation pump 13. The pH value of the slurry is between 5.5-6.5, which is very conducive to _SO2 at this pH value. Absorption, and since most of the HCl and HF in the flue gas have been removed in the primary desulfurization area, the chloride content in the circulating slurry in the secondary desulfurization area is very low, so that the removal of SO ₂ in the secondary desulfurization area can be maximized The flue gas after desulfurization is demisted through the demister 12, and the desulfurized products in the secondary desulfurization area and the demisted products flow back to the slurry tank 2. The demisted flue gas is reheated by the reheater, and then discharged from the chimney.

Since the slurry tank 1 operates at a low pH value, it is very beneficial to the dissolution of limestone, the oxidation of sulfite, and the generation of gypsum, so that the utilization rate of limestone can be improved, and the sulfite returned to the slurry tank 1 can be almost completely eliminated. to oxidize. In addition, since most of the HCl and HF in the flue gas are removed in the primary desulfurization area and flow into the slurry tank 1, it is only necessary to strengthen the anticorrosion of the slurry tank 1, and it is not necessary to use more expensive alloys for all the slurry tanks to prevent Chloride corrosion can save construction costs.

Claims (4)

1. two circulation wet flue gas desulfurizers of cross-flow in the flue, comprise flue, slurry tank, dividing plate, air compressor, slush pump, spray thrower, coverage angle, demister, charging spout, evaporative cooling section, condensation heat release section, circulating pump, it is characterized in that, below flue, be provided with the slurry tank that is connected as a single entity with flue; The spray desulfurization is carried out in flue, is furnished with one-level spray thrower and secondary spray thrower in the flue, and the slurry pH value difference of two-stage spray thrower spray; Be provided with in the front end of two ends spray equipment and middle flue upper end and cover the angle, be provided with demister in the rear positions of secondary spray thrower.

2. the two circulation wet flue gas desulfurizers of cross-flow in the flue according to claim 1, it is characterized in that described slurry tank is split up into one-level slurry tank and secondary slurry tank by dividing plate, the slurry tank bottom is provided with agitating device, the lower end of dividing plate is provided with communicating door, and the slurries of one-level slurry tank replenish and can be replenished by the overflow mode by communicating door or on dividing plate top by the secondary slurry tank.

3. the two circulation wet flue gas desulfurizers of cross-flow in the flue according to claim 1, it is characterized in that: the one-level spray thrower connects the one-level slurry tank by pipeline and slurry circulating pump; The secondary spray thrower connects the secondary slurry tank by pipeline and slurry circulating pump.

4. the two circulation wet flue gas desulfurizers of cross-flow in the flue according to claim 1, it is characterized in that: evaporative cooling section before the one-level spray thrower and the condensation heat release section behind the secondary spray thrower are respectively equipped with series connection separated heat pipe reheater, are provided with circulating pump on the pipeline of condensed fluid.

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