CN212383462U - Wet flue gas desulfurization system - Google Patents
Wet flue gas desulfurization system Download PDFInfo
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- CN212383462U CN212383462U CN202020833183.6U CN202020833183U CN212383462U CN 212383462 U CN212383462 U CN 212383462U CN 202020833183 U CN202020833183 U CN 202020833183U CN 212383462 U CN212383462 U CN 212383462U
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Abstract
The utility model relates to the technical field of desulphurization devices, in particular to a wet flue gas desulphurization system, which comprises a pulping device, a slurry conveying device, an absorption device and a slurry recovery device which are sequentially communicated; the pulping device comprises a carbide slag powder bin, a limestone powder bin and a pulping tank; the bottom ends of the carbide slag powder bin and the limestone powder bin are respectively communicated with the pulping groove, and the communicated passages are respectively provided with a discharging valve; the pulping tank is communicated with the absorption device through the pulp conveying device; the slurry conveying device comprises a conveying pipeline and a large-flow slurry supply pump and a fine-flow slurry supply pump which are arranged in parallel on the conveying pipeline, and the pulping groove passes through the conveying pipeline and the absorption device. The wet desulphurization system can independently use the carbide slag or the limestone as the desulfurizer to operate, can also use the carbide slag and the limestone as the mixed desulfurizer to operate, and can realize the mutual safe switching between the desulfurizers.
Description
Technical Field
The utility model belongs to the technical field of desulphurization unit technique and specifically relates to a wet flue gas desulfurization system is related to.
Background
The energy composition of China is mainly coal, and the consumption amount of the coal accounts for about 70 percent of the total consumption amount of primary energy. Coal is used as a main fuel in coal-fired power plants in China to generate electricity, the coal is directly combusted to release a large amount of sulfur dioxide, and according to statistics, the sulfur dioxide discharged by the coal serving as a main dye accounts for about 70 percent of the total national sulfur dioxide discharge.
At present, nearly two hundred kinds of desulfurization methods exist in power plants at home and abroad, the desulfurization methods mainly comprise three main types of dry desulfurization, wet desulfurization and semi-dry desulfurization, and the desulfurization stages of coal can be divided into desulfurization before combustion, desulfurization during combustion and desulfurization after combustion. The wet desulphurization technology using calcium as a desulfurizer can meet the requirement of near zero emission under most flue gas conditions, has the advantages of high utilization rate of the desulfurizer, mature technical development, stable operation and the like, and is widely applied to coal-fired power plants.
In the calcium-based wet flue gas desulfurization, the main desulfurizer is limestone which comes from a limestone mine, and the mined limestone is crushed into 250-350-mesh limestone powder for a flue gas desulfurization system. However, due to the long-term exploitation and ecological protection, limestone ore is increasingly difficult to exploit, correspondingly, limestone powder is increasingly expensive, and the unit cost of flue gas desulfurization operation is increased. Therefore, the search for alternative desulfurizing agents capable of replacing limestone, and applicable to electric power and industrial desulfurization, is a major problem faced by the current wet desulfurization technology.
The carbide slag is solid waste slag generated in the alkali recovery process of the paper industry or generated in the alkali production process of an alkali factory. The carbide slag discharged by the alkali-making industry only reaches millions of tons every year, and the carbide slag discharged by the paper-making industry is more. The main component of the carbide slag is calcium hydroxide, which has the advantages of high solubility, high reaction speed, high desulfurization efficiency and the like, and can be used as a calcium source for wet flue gas desulfurization.
However, the carbide slag is a byproduct of industrial production, the source of the carbide slag is influenced by the production stability of chemical enterprises, and the carbide slag has the risk of fluctuation of supply quantity. That is, when the production of chemical enterprises stops or the yield decreases, the supply of carbide slag stops or decreases, which is very easy to cause the problem of desulfurizer supply interruption or insufficient supply for enterprises using carbide slag as desulfurizer. Therefore, for desulfurization enterprises, the desulfurizing agent needs to be replaced when necessary, that is, the carbide slag desulfurizing agent is switched to the limestone desulfurizing agent, or the limestone desulfurizing agent is switched to the carbide slag desulfurizing agent after the carbide slag desulfurizing agent is normally supplied, so as to ensure the stability of the flue gas desulfurization production process.
In the process of switching the limestone desulfurizer to the carbide slag desulfurizer, after the supply of the limestone desulfurizer is cut off and the carbide slag desulfurizer is supplied instead, the carbide slag desulfurizer can maintain the pH state required by the desulfurization slurry after switching due to the high activity of the carbide slag desulfurizer, thereby ensuring that the flue gas desulfurization efficiency is not reduced in the switching process. However, after the carbide slag desulfurizer is switched to the limestone desulfurizer, due to high activity and high viscosity of the carbide slag desulfurizer, limestone in the desulfurization slurry is easily wrapped by the carbide slag after switching, SO that the content of effective limestone components in the slurry is low, the desulfurization efficiency of the desulfurization system cannot maintain the initial state, the desulfurization efficiency is reduced, and further the clean flue gas emission SO is caused2Rise and may take a longer time to re-establish a stable limestone desulfurization state, with the risk of longer periods of overproof desulfurization system emissions.
Therefore, it is an urgent technical problem to develop a flue gas desulfurization system suitable for limestone and carbide slag desulfurizer to solve the risk in the desulfurizer switching process.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a wet flue gas desulfurization system, this wet flue gas desulfurization system can the exclusive use carbide slag or lime stone move as the desulfurizer, also can use carbide slag and lime stone to mix the desulfurizer operation to can realize switching over each other safely between the desulfurizer, in order to adapt to the desulfurizer supply change condition.
The utility model provides a wet flue gas desulfurization system, which comprises a pulping device, a slurry conveying device, an absorption device and a slurry recovery device which are sequentially communicated;
the pulping device comprises a carbide slag powder bin, a limestone powder bin and a pulping tank;
the bottom ends of the carbide slag powder bin and the limestone powder bin are respectively communicated with the pulping groove, and the communicated passages are respectively provided with a discharging valve;
the pulping tank is communicated with the absorption device through the pulp conveying device;
the slurry conveying device comprises a conveying pipeline and a large-flow slurry supply pump and a fine-flow slurry supply pump which are arranged in parallel on the conveying pipeline, and the pulping groove passes through the conveying pipeline and the absorption device.
In a wet flue gas desulfurization system, limestone slurry or carbide slag slurry or mixed slurry of limestone and carbide slag is prepared by a pulping device, then the slurry in the pulping device is conveyed to an absorption device by a conveying device, and SO in flue gas is finished in the absorption device2The slurry after the desulfurization reaction is discharged into a slurry recovery device, and is further recovered and treated by the slurry recovery device. In practice, in order to solve the problems that the desulfurization efficiency in the absorption device cannot be maintained in the initial state and the desulfurization efficiency is reduced due to the low activity of limestone and the low content of effective limestone components in the desulfurization slurry after switching in the process of switching the carbide slag slurry and the limestone slurry, and a stable limestone desulfurization state may need to be reestablished for a long time,there is a risk that the emissions of the desulfurization system will exceed standards for a longer period of time. Therefore, for solving the above problem the utility model discloses an among the wet flue gas desulfurization system, slurrying device includes carbide slag powder storehouse, limestone powder storehouse and slurrying groove to the bottom of carbide slag powder storehouse and limestone powder storehouse respectively with the slurrying groove intercommunication, from this slurrying groove can prepare the limestone slurry or carbide slag slurry or the mixed slurry between them of arbitrary concentration. The slurry conveying device comprises a conveying pipeline, a large-flow slurry supply pump and a fine-flow slurry supply pump which are arranged on the conveying pipeline in parallel, and therefore slurry in the pulping tank can be conveyed to the absorption device through the conveying pipeline and can be adjusted to enter the absorption device through the large-flow slurry supply pump and the fine-flow slurry supply pump according to the operation condition of the absorption device. The wet flue gas desulfurization system can realize the independent operation of the limestone or carbide slag desulfurizer, also can realize the operation of the mixed desulfurizer of the limestone and the carbide slag, and can realize the safe switching of the carbide slag and the limestone desulfurizer so as to adapt to the change requirement of the desulfurizer.
Further, the absorption device comprises an absorption tower and a circulating pump arranged outside the absorption tower;
a slurry pool, a spraying layer and a demister are sequentially arranged in the absorption tower along the direction from the tower bottom to the tower top;
the pulping tank is communicated with the slurry pool through the conveying pipeline;
and the inlet and the outlet of the circulating pump are respectively communicated with the slurry tank and the spraying layer through pipelines.
The absorption device comprises an absorption tower and a circulating pump arranged outside the tower, slurry in the pulping tank is conveyed to a slurry tank at the bottom of the absorption tower, and then is supplied in an interval manner due to the supply of limestone slurry, and the carbide slag is supplied in a continuous manner, SO that the circulating pump outside the tower can pump the slurry in the slurry tank to a spraying layer, the atomization and the spraying of the slurry are realized by the spraying layer, the slurry falling down interacts with the entering flue gas, and the SO in the flue gas is realized2The flue gas with sulfide removed is discharged from the bottom end of the absorption tower after passing through a demister.
Further, the absorption device also comprises an oxidation fan arranged outside the absorption tower, and the oxidation fan is communicated with the bottom of the slurry pool through an air pipe;
and the air pipe positioned in the slurry pool is vertical to the axial direction of the absorption tower, and a plurality of first nozzles are equidistantly arranged on the air pipe.
CaCO in slurry3Or Ca (OH)2With SO in flue gas2CaSO is generated after the reaction3Therefore, in order to fully oxidize the sulfite and convert the sulfite into sulfate, an oxidation fan is arranged outside the absorption tower and is communicated with the bottom of the slurry pool through an air pipe to supplement air with enough quantity for the slurry in the slurry pool. And in order to ensure that the blown air is fully contacted with the slurry, the air pipe positioned in the slurry pool is vertical to the axial direction of the absorption tower, and a plurality of first nozzles are arranged on the air pipe at equal intervals.
Furthermore, a demister washing component is also arranged in the absorption tower;
the demister flushing component is arranged above the demister;
and a plurality of second nozzles are arranged on the demister washing part at equal intervals.
Smuggle a large amount of fog grains and thick liquid secretly in the flue gas after the desulfurization, the droplet in the flue gas is strikeed and is laid on the defroster blade and collect, and the droplet collects and forms rivers, because of the action of gravity, falls to the thick liquid pond in, and the particulate matter in the fog grain can be attached to on the blade of defroster, consequently, still is provided with the defroster and washes the part in the top of defroster to and clear away the particulate matter on the defroster blade in time. In order to improve the contact area between the flushing liquid and the demister blades, a plurality of second nozzles are arranged on the demister flushing component at equal intervals.
Further, the slurry recovery device comprises a slurry discharge pump, a gypsum cyclone, a vacuum belt conveyor and a filtrate tank;
the inlet end and the outlet end of the slurry discharge pump are respectively and correspondingly communicated with the bottom end of the slurry tank and the inlet end of the gypsum cyclone, and the overflow outlet end of the gypsum cyclone is communicated with the slurry tank;
the outlet end at the bottom of the gypsum cyclone is arranged above the vacuum belt conveyor, and the liquid outlet end of the vacuum belt conveyor is communicated with the filtrate tank;
the filtrate tank is communicated with the pulping tank in a reverse direction.
The slurry recovery device comprises a slurry discharge pump, a gypsum cyclone, a vacuum belt conveyor and a filtrate tank, wherein the slurry discharge pump discharges the slurry at the bottom of the slurry tank to the gypsum cyclone, in the gypsum cyclone, because of the particle size difference between coarse particles and fine particles in the slurry, when the slurry is subjected to centrifugal force, centripetal buoyancy and the like, under the action of centrifugal sedimentation, most of the fine particles can flow back to the slurry tank, most of the coarse particles are discharged to the vacuum belt conveyor from the bottom end of the gypsum cyclone, liquid-solid separation is realized, the filtrate is discharged into the filtrate tank for pulping or discharge, and the solid gypsum is transported outwards.
Further, the device also comprises a process water tank;
the process water tank is communicated with the demister flushing component.
The cleaning liquid of the demister flushing part and the process water required for the dilution liquid in the pulping tank can be taken from the process water tank.
Furthermore, slurrying device still includes the air compressor machine, the gas output end of air compressor machine respectively with carbide slag powder storehouse with the bottom intercommunication of lime stone powder storehouse.
In order to prevent the bottoms of the carbide slag powder bin and the limestone powder bin from being blocked, an air compressor is further arranged in the pulp making device, and the air compressor can provide compressed air for the material outlet ends at the bottoms of the carbide slag powder bin and the limestone powder bin so as to loosen materials.
Further, a stirrer and a densimeter are arranged inside the pulping tank.
In order to monitor the preparation concentration of the slurry in the pulping tank in real time, a densimeter is arranged in the pulping tank.
Further, a side-feeding stirrer, a pH meter, a density meter and a liquid level meter are arranged inside the slurry pool.
A side entry agitator inside the slurry tank may promote thorough mixing of the air blown by the oxidation fan with the slurry.
The utility model also discloses an operation method of above-mentioned wet flue gas desulfurization system, including following step:
after preparing the slurry in the slurry preparation tank, conveying the slurry to an absorption device through a conveying pipeline, adjusting the pH value of the slurry in the absorption device through a large-flow slurry supply pump and a fine-flow slurry supply pump, finishing the flue gas desulfurization process of the slurry in the absorption device, and feeding the slurry subjected to desulfurization treatment into a slurry recovery device;
wherein, when the wet flue gas desulfurization system adopts limestone as a desulfurizing agent to operate, the concentration of limestone slurry is 1-30%;
when the wet flue gas desulfurization system adopts the carbide slag as a desulfurizing agent to operate, the mass concentration of carbide slag slurry is 1-30%, and the pH value of the slurry in the absorption device is 5-6;
when the wet flue gas desulfurization system adopts limestone and carbide slag as the mixed desulfurizer to operate, the mass concentration of the slurry of the mixed desulfurizer is 1-40%, wherein the mass concentration of the limestone is 1-25%, the mass concentration of the carbide slag is 1-25%, and the pH value of the slurry in the absorption device is 5-6;
when the wet flue gas desulfurization system is switched from a limestone desulfurizer to a carbide slag desulfurizer, after the last limestone slurry is supplied, 1-30% of carbide slag slurry with mass concentration is supplied to the absorption device, and the pH of the slurry in the absorption device is controlled to be 5-6;
when the wet flue gas desulfurization system is switched from the carbide slag desulfurizer to the limestone desulfurizer, the change of the concentration of the desulfurizer in the slurrying tank comprises an initial stage, a middle stage, a later stage and a complete switching stage,
in the initial stage, the mass concentration of the carbide slag in the mixed desulfurizer is 10-25%, and the mass concentration of the limestone is 10-20%;
in the intermediate stage, the mass concentration of the carbide slag in the mixed desulfurizer is 5-15%, and the mass concentration of the limestone is 5-25%;
in the later stage, the mass concentration of the carbide slag in the mixed desulfurizer is 5-10%, and the mass concentration of the limestone is 5-30%;
and in the complete switching stage, the supply of the mixed desulfurizer is stopped when the mass concentration of calcium carbonate in the slurry is detected to be more than 10%, and the limestone slurry with the mass concentration of 5-30% is switched.
The utility model discloses a wet flue gas desulfurization system, when using the lime stone as the desulfurizer operation, the powder transport vechicle sends the lime stone powder into lime stone powder storehouse, sends into the slurrying groove through the unloading valve, adds the process water simultaneously, and the preparation concentration is 1-30% lime stone thick liquid, then according to the needs of desulfurization in the absorption tower, supplies the thick liquid pond of thick liquid pump sending to the absorption tower through large-traffic for flue gas SO2Absorption;
when the carbide slag is used as a desulfurizer to operate, the carbide slag powder is conveyed into a limestone powder bin by a powder conveying vehicle, conveyed into a slurrying tank through a blanking valve, simultaneously added with process water to prepare carbide slag slurry with the concentration of 1-30%, and conveyed to a slurry tank in an absorption tower through a fine flow slurry supply pump for flue gas SO2Absorbing, wherein the pH value of the slurry in the absorption tower is controlled by adjusting the flow of the fine flow slurry supply pump, and the set value is 5-6;
when limestone and carbide slag are used as the mixed desulfurizer to operate, mixed desulfurizer slurry with the mass concentration of 1-40% is prepared in a slurry preparation tank, wherein the mass concentration of the limestone is 1-25%, the mass concentration of the carbide slag is 1-25%, and the mixed desulfurizer slurry is conveyed to a slurry pool in an absorption tower through a large-flow slurry supply pump and a fine-flow slurry supply pump and is used for SO in flue gas2The pH value of the slurry in the slurry pool is 5-6, and the flow can be controlled by a fine flow supply pump. The supply of the mixed desulfurizer slurry can adopt an intermittent type or a continuous type according to different compositions of the mixed desulfurizer slurry;
when the limestone desulfurizer is switched to the carbide slag desulfurizer, because the supply of limestone desulfurizer slurry is in an intermittent manner, after the last limestone slurry supply, carbide slag slurry with the mass concentration of 1-30% is supplied to the absorption device, and the pH of the slurry in the absorption device is controlled to be 5-6, so that the desulfurizer is switched, preferably, the mass concentration of the carbide slag is 5-25%;
when the carbide slag desulfurizer is switched to the limestone desulfurizer, firstly, 1-30% of slurry of the carbide slag desulfurizer is prepared in a slurry preparation tank, the mass concentration of the carbide slag is preferably 1-15%, then, limestone powder in a limestone powder bin is fed into the slurry preparation tank to prepare slurry with the mass concentration of the limestone being 1-30%, the mass concentration of the limestone is preferably 15-25%, the total mass concentration of the mixed desulfurizer is 15-40%, the slurry of the mixed desulfurizer is conveyed to an absorption tower through a large-flow slurry supply pump and a fine-flow slurry supply pump, the running pH of the slurry in the absorption tower is controlled to be 5-6, and when the mass content of calcium carbonate in the slurry in a slurry pool exceeds 10%, the mixed desulfurizer is stopped to be supplied and switched to the limestone slurry.
The utility model discloses a wet flue gas desulfurization system compares with prior art, has following advantage:
the wet flue gas desulfurization system of the utility model comprises a pulping device, a conveying device, an absorption device and a slurry recovery device, the slurry making device is provided with a carbide slag powder bin, a limestone powder bin and a slurry making tank, the slurry making tank can prepare limestone slurry or carbide slag slurry or mixed slurry of the limestone slurry and the carbide slag slurry with any concentration, and is conveyed to the absorption device through a conveying pipeline, and the conveying flow can be adjusted by a large-flow slurry supply pump and a fine-flow slurry supply pump on the conveying pipeline, therefore, the wet desulphurization system can be operated by independently using carbide slag or limestone as a desulfurizer, and can also be operated by using a mixed desulfurizer of carbide slag and limestone, and mutual safe switching between the desulfurizing agents can be realized, so that the desulfurizing agent supply change condition is adapted, and the problems that the desulfurizing efficiency is reduced and the discharge exceeds the standard risk exists in the carbide slag and limestone slurry switching process are solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a simplified diagram of a wet flue gas desulfurization system according to the present invention;
fig. 2 is a schematic diagram of the wet flue gas desulfurization system of the present invention.
Description of reference numerals:
1: a pulping device; 2: a slurry delivery device; 3: an absorption device; 4: a slurry recovery device; 5: a carbide slag powder bin; 6: a limestone powder bin; 7: a pulping groove; 8: a discharge valve; 9: a delivery conduit; 10: a large-flow slurry supply pump; 11: a fine flow slurry supply pump; 12: an absorption tower; 13: a circulation pump; 14: a slurry tank; 15: a spray layer; 16: a demister; 17: an oxidation fan; 18: an air duct; 19: a first nozzle; 20: a demister flushing component; 21: a second nozzle; 22: a slurry discharge pump; 23: a gypsum cyclone; 24: a vacuum belt conveyor; 25: a filtrate tank; 26: a process water tank; 27: an air compressor; 28: a stirrer; 29: a densitometer; 30: a side entry agitator; 31: a pH meter; 32: a liquid level meter.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
As shown in fig. 1-2, the wet flue gas desulfurization system of the present invention comprises a slurry preparation device 1, a slurry delivery device 2, an absorption device 3 and a slurry recovery device 4 which are sequentially connected; the pulping device 1 comprises a carbide slag powder bin 5, a limestone powder bin 6 and a pulping tank 7; the bottom ends of the carbide slag powder bin 5 and the limestone powder bin 6 are respectively communicated with the pulping groove 7, and the communicated passages are respectively provided with a discharging valve 8; the pulping tank 7 is communicated with the absorption device 3 through the slurry conveying device 2; slurry conveying device 2 includes pipeline 9 and parallel arrangement is in large-traffic slurry supply pump 10 and meticulous flow slurry supply pump 11 on pipeline 9, slurrying groove 7 passes through pipeline 9 with absorbing device 3 intercommunication.
In the wet flue gas desulfurization system of the present invention, when only limestone or carbide slag desulfurizer is used, only the material in the limestone powder bin 6 or carbide slag powder bin 5 needs to be put down into the slurrying trough 7, and then conveyed to the absorption device 3 through the conveying pipeline 9, and the conveying flow is regulated by the large-flow slurry supply pump 10 or the fine-flow slurry supply pump 11; when the mixed slurry of the limestone powder and the carbide slag is used, a certain amount of materials in the limestone powder bin 6 or the carbide slag powder bin 5 are put into the pulping tank 7 according to the concentration of the preset slurry, the mixed slurry is prepared in the pulping tank 7, and the mixed slurry is conveyed into the absorption device 3; when the limestone desulfurizer is required to be switched into the carbide slag desulfurizer, the supply of the limestone desulfurizer can be directly cut off, and the carbide slag desulfurizer is supplied instead, so that the carbide slag desulfurizer can maintain the required pH of the desulfurization slurry after switching due to higher activity of the carbide slag desulfurizer, and the flue gas desulfurization efficiency is not reduced in the switching process; when the carbide slag desulfurizer is switched to the limestone desulfurizer, the carbide slag has high activity and coats limestone, so that the concentration of the supplied carbide slag is higher than that of the limestone at the initial switching stage to ensure that the desulfurization efficiency is not reduced, and along with the addition of the carbide slag and the limestone, when the mass content of calcium carbonate in the slurry exceeds 10 percent, the supply of the mixed desulfurizer is stopped, and the limestone desulfurizer is switched to be only supplied. Therefore, the utility model discloses a wet flue gas desulfurization system can realize carbide slag or the independent operation of lime stone desulfurizer, also can realize lime stone and the mixed desulfurizer operation of carbide slag to, switch the in-process at lime stone and carbide slag, can not influence desulfurization efficiency.
Wherein, the slurry supply flow of the large-flow slurry supply pump 10 is 5-100 times of that of the fine-flow slurry supply pump 11, and preferably, the slurry supply flow of the large-flow slurry supply pump 10 is 5-50 times of that of the fine-flow slurry supply pump 11. When the independent limestone slurry is supplied, a large-flow slurry supply pump 10 is used; when the carbide slag slurry is supplied, a fine flow supply pump 11 is used; in the slurry mixing and slurry switching process, a combined supply method is used.
On the basis of the technical scheme, the absorption device 3 further comprises an absorption tower 12 and a circulating pump 13 arranged outside the absorption tower; a slurry pool 14, a spraying layer 15 and a demister 16 are sequentially arranged in the absorption tower 12 along the direction from the tower bottom to the tower top; the pulping tank 7 is communicated with the slurry pool 14 through the conveying pipeline 9; the inlet and the outlet of the circulating pump 13 are respectively communicated with the slurry tank 14 and the spraying layer 15 through pipelines.
Since the supply method of the limestone slurry is intermittent type, the supply method of the carbide slag is continuous type, and the supply method of the mixed slurry is intermittent type or continuous type, therefore,the circulating pump 13 is arranged outside the absorption tower 12, and the circulating pump 13 can pump the slurry in the slurry pool 14 into the spraying layer 15, atomize and then fall down in the absorption tower 12. The raw flue gas enters the absorption tower 12 from the inlet flue of the tower, moves from bottom to top in the absorption tower 12, and contacts with slurry flowing downwards in a counter-current manner to complete flue gas washing and SO (sulfur oxide) separation2And absorbing, wherein the purified flue gas passes through a demister 16 and then is discharged out through a chimney.
In order to promote the calcium sulfite in the slurry to be fully oxidized into calcium sulfate, the absorption device 3 further comprises an oxidation fan 17 arranged outside the absorption tower 12, and the oxidation fan 17 is communicated with the bottom of the slurry tank 14 through an air pipe 18; an air pipe 18 positioned in the slurry tank 14 is perpendicular to the axial direction of the absorption tower 12, and a plurality of first nozzles 19 are arranged on the air pipe 18 at equal intervals.
On the basis of the above preferred technical solution, further, a demister washing unit 20 is further provided inside the absorption tower 12; the demister flushing unit 20 is disposed above the demister 16; the demister washing unit 20 has a plurality of second nozzles 21 equidistantly formed. The demister washing unit 20 disposed above the demister 16 can remove particulate matter attached to the demister 16 in time.
In order to improve the utilization rate of the slurry, the slurry recovery device 4 comprises a slurry discharge pump 22, a gypsum cyclone 23, a vacuum belt conveyor 24 and a filtrate tank 25; the inlet end and the outlet end of the slurry discharge pump 22 are respectively and correspondingly communicated with the bottom end of the slurry tank 14 and the inlet end of the gypsum cyclone 23, and the overflow outlet end of the gypsum cyclone 23 is communicated with the slurry tank 14; the outlet end at the bottom of the gypsum cyclone 23 is arranged above the vacuum belt conveyor 24, and the liquid outlet end of the vacuum belt conveyor 24 is communicated with the filtrate tank 25; the filtrate tank 25 is in reverse communication with the slurrying tank 7.
On the basis of the above preferred technical scheme, further, the system further comprises a process water tank 26; the process water tank 26 is in communication with the demister flushing unit 20.
In order to solve the problem that the bottoms of the carbide slag powder bin 5 and the limestone powder bin 6 are blocked, the pulping device 1 further comprises an air compressor 27, and the gas output end of the air compressor 27 is communicated with the bottoms of the carbide slag powder bin 5 and the limestone powder bin 6 respectively.
In addition to the above preferred technical solution, more preferably, a stirrer 28 and a densimeter 29 are provided inside the slurrying tank 7; inside the slurry tank 14 are provided a side entry mixer 30, a pH meter 31, a density meter 29 and a level meter 32.
The wet flue gas desulfurization system in the preferred technical scheme is applied to the flue gas desulfurization technology of a certain power plant. The carbide slag and limestone used in the following examples are commercially available products.
EXAMPLE 1 limestone flue gas desulfurization
The process water 10m is put into a pulping tank 7 with a stirrer and a diameter of 2.5m and a height of 2.5m3And then 2.5 tons of 350-mesh limestone desulfurizer is put down from a limestone powder bin 6 to obtain limestone desulfurization slurry with the mass concentration of 20 percent. The diameter of the absorption tower 12 is 2.5m, the height is 25m, and 5 spraying layers 15 are arranged in the absorption tower. Limestone slurry in the pulping groove 7 is intermittently fed into the absorption tower 12 through a large-flow slurry supply pump 10, and the conveying flow is 600L/min. The amount of flue gas from the boiler is 40000m3The original gas fume of/h enters an absorption tower 12, the temperature of the gas fume is 150 ℃, and SO is arranged at an inlet2At a concentration of 1500mg/Nm3. Under the state that the three spraying layers 15 are opened, the liquid-gas ratio is 10, the desulfurization efficiency is up to 85 percent, the pH value of slurry in the desulfurization tower is within the range of 5.5-6.2, and the slurry density is less than 1.2. The slurry after the completion of desulfurization is discharged out intermittently through a gypsum cyclone 23 and a vacuum belt conveyor 24 at a flow rate of 500L/min.
EXAMPLE 2 carbide slag flue gas desulfurization
The process water 9m is put into a pulping tank 7 with a stirrer and a diameter of 2.5m and a height of 2.5m3And then putting down 1 ton of powdery carbide slag desulfurizer from the carbide slag powder bin 5 to obtain 10% mass concentration carbide slag desulfurization slurry, wherein the pH value of the carbide slag desulfurizer slurry in the slurrying tank 7 is 12.3. The diameter of the absorption tower 12 is 2.5m, the height is 25m, and 5 spraying layers 15 are arranged. The carbide slag slurry in the slurry making tank 7 is continuously fed into an absorption tower 12 through a fine flow supply pump 11, and the conveying flow is 9.0-10.5L/min. From boiler flue gasesThe amount is 40000m3The original per hour flue gas enters an absorption tower 12, the temperature of the flue gas is 150 ℃, and the concentration of SO2 at an inlet is 1500mg/Nm3And the pH value of the slurry in the desulfurizing tower is controlled within the range of 5.0-6.0 by adjusting the slurry conveying flow, the liquid-gas ratio is 10 under the state that the three spraying layers 15 are opened, the desulfurizing efficiency is higher than 90%, and the slurry density is less than 1.1. And continuously discharging the desulfurized slurry through a gypsum cyclone 23 and a vacuum belt conveyor 24 at the flow rate of 9-10L/min.
Example 3 flue gas desulfurization with limestone and carbide slag mixed desulfurizing agent
The process water 10m is put into a pulping tank 7 with a stirrer and a diameter of 2.5m and a height of 2.5m3Then, 2.5 tons of 350-mesh limestone desulfurizer and 0.1 ton of powdery carbide slag desulfurizer are respectively put down from a limestone powder bin 6 and a carbide slag powder bin 5 to obtain mixed desulfurizer slurry with the mass concentration of limestone being 20 percent and the mass concentration of carbide slag being 1 percent, the pH value of the mixed desulfurizer slurry is 12.1, and the total mass concentration of the desulfurizer is 20.6 percent. The diameter of the absorption tower 12 is 2.5m, the height is 25m, and 5 spraying layers 15 are arranged in the absorption tower. The mixed desulfurizer slurry in the pulping groove 7 is continuously fed into the absorption tower 12 through a large-flow slurry supply pump 10 and a fine-flow slurry supply pump 11, wherein the conveying flow of the large-flow slurry supply pump 10 is 90L/min, and the conveying flow of the fine-flow slurry supply pump 11 is 9-10L/min. The amount of flue gas from the boiler is 40000m3The original gas fume of/h enters an absorption tower 12, the temperature of the gas fume is 150 ℃, and SO is arranged at an inlet2The concentration is 1500mg/Nm3. Under the state that three-layer spraying is started, the liquid-gas ratio is 10, the desulfurization efficiency is higher than 90%, the conveying flow is adjusted by a fine flow slurry supply pump 11, the pH value of slurry in the absorption tower 12 is controlled to be maintained at 5.0-6.0, and the slurry density is less than 1.2. The slurry after the completion of desulfurization was discharged intermittently through a gypsum cyclone 23 and a vacuum belt conveyor 24 at a flow rate of 600L/min.
Example 4 switching limestone desulfurization to carbide slag desulfurization
In the limestone desulfurization operation mode in example 1, to switch to the carbide slag desulfurization operation mode, the carbide slag desulfurizer slurry is prepared according to the method in example 2, and then the slurry supply and discharge modes in example 2 are directly switched, that is, the switching from limestone desulfurization to carbide slag desulfurization is completed. The desulfurization efficiency of the whole switching process is higher than 85%.
Example 5 switching of carbide slag desulfurization to limestone desulfurization
The operation mode of carbide slag desulfurization in example 2 was switched to the operation mode of limestone desulfurization in example 1, and a mixed desulfurization agent slurry of limestone and carbide slag was prepared in the same manner as in example 3, and was switched to the operation mode of example 3, and when the concentration of calcium carbonate in the desulfurization slurry in the absorption tower 12 reached 10% or more, the operation mode was switched to the operation mode of limestone desulfurization in example 1. The desulfurization efficiency of the whole switching process is higher than 85%.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.
Claims (9)
1. A wet flue gas desulfurization system is characterized by comprising a pulping device (1), a slurry conveying device (2), an absorption device (3) and a slurry recovery device (4) which are sequentially communicated;
the pulping device (1) comprises a carbide slag powder bin (5), a limestone powder bin (6) and a pulping tank (7);
the bottom ends of the carbide slag powder bin (5) and the limestone powder bin (6) are respectively communicated with the pulping groove (7), and the communicated passages are respectively provided with a discharging valve (8);
the pulping tank (7) is communicated with the absorption device (3) through the pulp conveying device (2);
slurry conveying device (2) are in including pipeline (9) and parallel setting large-traffic confession stuff pump (10) and meticulous flow confession stuff pump (11) on pipeline (9), slurrying groove (7) are passed through pipeline (9) with absorbing device (3) intercommunication.
2. The wet flue gas desulfurization system according to claim 1, wherein the absorption device (3) comprises an absorption tower (12) and a circulation pump (13) disposed outside the tower;
a slurry pool (14), a spraying layer (15) and a demister (16) are sequentially arranged in the absorption tower (12) along the direction from the bottom of the tower to the top of the tower;
the pulping tank (7) is communicated with the slurry pool (14) through the conveying pipeline (9);
and the inlet and the outlet of the circulating pump (13) are respectively communicated with the slurry pool (14) and the spraying layer (15) through pipelines.
3. The wet flue gas desulfurization system of claim 2, wherein the absorption device (3) further comprises an oxidation fan (17) disposed outside the absorption tower (12), the oxidation fan (17) being in communication with the bottom of the slurry tank (14) through an air duct (18);
an air pipe (18) positioned in the slurry tank (14) is vertical to the axial direction of the absorption tower (12), and a plurality of first nozzles (19) are arranged on the air pipe (18) at equal intervals.
4. The wet flue gas desulfurization system of claim 3, wherein a demister washing unit (20) is further disposed inside the absorption tower (12);
the demister flushing unit (20) is arranged above the demister (16);
and a plurality of second nozzles (21) are equidistantly arranged on the demister washing component (20).
5. The wet flue gas desulfurization system of claim 4, wherein the slurry recovery device (4) comprises a slurry discharge pump (22), a gypsum cyclone (23), a vacuum belt conveyor (24) and a filtrate tank (25);
the inlet end and the outlet end of the slurry discharge pump (22) are respectively and correspondingly communicated with the bottom end of the slurry tank (14) and the inlet end of the gypsum cyclone (23), and the overflow outlet end of the gypsum cyclone (23) is communicated with the slurry tank (14);
the bottom outlet end of the gypsum cyclone (23) is arranged above the vacuum belt conveyor (24), and the liquid outlet end of the vacuum belt conveyor (24) is communicated with the filtrate tank (25);
the filtrate tank (25) is reversely communicated with the pulping tank (7).
6. The wet flue gas desulfurization system of claim 5, further comprising a process water tank (26); the process water tank (26) is in communication with the demister flushing component (20).
7. The wet flue gas desulfurization system of claim 1, wherein the slurry preparation device (1) further comprises an air compressor (27), and a gas output end of the air compressor (27) is respectively communicated with the bottoms of the carbide slag powder bin (5) and the limestone powder bin (6).
8. The wet flue gas desulfurization system of claim 7, characterized in that an agitator (28) and a densitometer (29) are provided inside the slurrying tank (7).
9. The wet flue gas desulfurization system according to any one of claims 2 to 6, characterized in that a side-entry agitator (30), a pH meter (31), a density meter (29) and a level meter (32) are provided inside the slurry tank (14).
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| CN111450675A (en) * | 2020-05-19 | 2020-07-28 | 大唐环境产业集团股份有限公司 | Wet flue gas desulfurization system and system operation method |
| CN111450675B (en) * | 2020-05-19 | 2023-11-21 | 大唐环境产业集团股份有限公司 | Wet flue gas desulfurization system and system operation method |
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