Summary of the invention
The invention provides the two circulation Wet Limestone Desulfurization device and methods of a kind of double tower, solve that existing Wet Limestone Desulfurization technology can't reach that very high desulfuration efficiency, gypsum moisture content is high, desulfurizer transform idle time long, to the technical problem of ature of coal bad adaptability.
For achieving the above object, the present invention adopts following technical scheme: the two circulation Wet Limestone Desulfurization devices of a kind of double tower, comprise the gas cleaning part, the absorbent supply section, slurries oxidizing and crystallizing part and gypsum slurries dehydration part, it is characterized in that: described gas cleaning part is made of one-level circulating absorption tower and secondary circulating absorption tower, and the one-level circulating flue gas at one-level circulating absorption tower top outlet is communicated with secondary circulating flue gas entrance in the middle part of the secondary circulating absorption tower through transmitting flue, and the secondary at the secondary circulating absorption tower top clean exhanst gas outlet that circulates is communicated with atmosphere by exit flue;
The inside hypomere of described one-level circulating absorption tower has one-level circulating absorption tower slurry pool, epimere has one-level circulating absorption tower spraying layer and one-level circulation demister, and one-level circulation demister is positioned at the top of one-level circulating absorption tower spraying layer, the one-level circulation circulation line that the shower of one-level circulating absorption tower spraying layer connects outward is connected with one-level circulating absorption tower slurry pool, is connected with one-level circulation circulating pump on this one-level circulation circulation line.
The inside hypomere of described secondary circulating absorption tower has secondary circulating absorption tower slurry pool, epimere has secondary circulating absorption tower spraying layer and secondary circulation demister, and secondary circulation demister is positioned at the top of secondary circulating absorption tower spraying layer, the secondary circulation circulation line that the shower of secondary circulating absorption tower spraying layer connects outward is connected with secondary circulating absorption tower slurry pool, is connected with secondary circulation circulating pump on this secondary circulation circulation line.
Described absorbent supply section is made of lime stone slurry case, lime stone slurry supply pump and flow inlet road, and the discharging opening of lime stone slurry case is communicated with one-level circulating absorption tower slurry pool, secondary circulating absorption tower slurry pool by lime stone slurry supply pump and flow inlet road.
Described slurries oxidizing and crystallizing part is made of oxidation fan, one-level circulating absorption tower oxidation spray gun, secondary circulating absorption tower oxidation spray gun and oxidation air pipeline, and oxidation fan is communicated with one-level circulating absorption tower slurry pool by oxidation air pipeline and one-level circulating absorption tower oxidation spray gun, and oxidation fan is communicated with secondary circulating absorption tower slurry pool by oxidation air pipeline and secondary circulating absorption tower oxidation spray gun.
Described gypsum slurries dehydration part is made of one-level circulation gypsum excavationg pump, gypsum cyclone and vacuum dehydration belt feeder, described one-level circulating absorption tower slurry pool is provided with the gypsum slurries outlet, and the gypsum slurries outlet is connected with the charging aperture of pipeline with the gypsum cyclone by the gypsum excavationg pump, and the discharging opening of gypsum cyclone is communicated with the charging aperture of vacuum dehydration belt feeder again.
Described secondary circulating absorption tower slurry pool is provided with the gypsum slurries Returning outlet, and the gypsum slurries Returning outlet returns pump by secondary circulation gypsum slurries and pipeline is communicated with one-level circulating absorption tower slurry pool.
Described secondary circulating absorption tower slurry pool is provided with the plaster serum rotational flow outlet, and the plaster serum rotational flow outlet is communicated with the charging aperture of slurries circulation cyclone by secondary circulation plaster serum rotational flow pump and pipeline, and the discharging opening of slurries circulation cyclone is communicated with one-level circulating absorption tower slurry pool, secondary circulating absorption tower slurry pool by pipeline again.
Be provided with one-level circulating absorption tower agitator in the described one-level circulating absorption tower slurry pool, be provided with secondary circulating absorption tower agitator in the secondary circulating absorption tower slurry pool.
A kind of two circulation Wet Limestone Desulfurization methods of double tower of having used the two circulation Wet Limestone Desulfurization devices of double tower, it is characterized in that step is as follows: steps A, it is inner that the former smoke inlet of former flue gas through one-level circulating absorption tower middle part enters the one-level circulating absorption tower, flue gas flow rate is controlled at 3.0~3.5m/s, gypsum slurries in the one-level circulating absorption tower stock tank is delivered in the shower on the one-level circulating absorption tower spraying layer by one-level circulation circulating pump and one-level circulation circulation line, then former flue gas is washed and falls in the one-level circulating absorption tower stock tank, the pH value of the gypsum slurries in this one-level circulating absorption tower stock tank is controlled at 4.6~5.0, the slurries stay cycle is controlled to be 5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours.
Step B, flue gas behind the once washing is upwards through the demist of one-level circulation demister, enter secondary circulating absorption tower inside through transmitting flue again, flue gas flow rate is controlled at 3.3~3.8m/s, gypsum slurries in the secondary circulating absorption tower stock tank is delivered in the shower on the secondary circulating absorption tower spraying layer by secondary circulation circulating pump and secondary circulation circulation line, then the flue gas behind the once washing is carried out secondary washing and fall in the secondary circulating absorption tower stock tank, the pH value of the gypsum slurries in this secondary circulating absorption tower stock tank is controlled at 5.8~6.4, the slurries stay cycle is controlled to be 4~5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours.
Flue gas after step C, the secondary washing is upwards through the demist of secondary circulation demister, removes behind the large drop again by the exit flue qualified discharge.
Gypsum slurries in the step D, one-level circulating absorption tower stock tank also is delivered to the gypsum cyclone by one-level circulation gypsum excavationg pump, and then eddy flow is delivered to the dehydration of vacuum dehydration belt feeder after concentrated again, finally obtains moisture content less than 10% gypsum crystal.
When carrying out steps A, step B, step C, gypsum slurries in the secondary circulating absorption tower slurry pool also returns pump by secondary circulation gypsum slurries and is delivered in the one-level circulating absorption tower stock tank, controls the liquid level equilibrium of one-level circulating absorption tower stock tank and secondary circulating absorption tower slurry pool with this.
When carrying out steps A, step B, step C, gypsum slurries in the secondary circulating absorption tower slurry pool is delivered to slurries circulation cyclone by secondary circulation plaster serum rotational flow pump, then eddy flow is concentrated by be delivered to respectively one-level circulating absorption tower stock tank, secondary circulating absorption tower slurry pool by pipeline, controls the serum density balance of one-level circulating absorption tower stock tank and secondary circulating absorption tower slurry pool with this.
The preparation method of the two circulation Wet Limestone Desulfurization devices of a kind of double tower, it is characterized in that step is as follows: step a, a newly-built circulating absorption tower with spraying layer and demister make this circulating absorption tower as the secondary circulating absorption tower; Step b, remove the exhanst gas outlet at top and being connected of exit flue of the circulating absorption tower in the Wet Limestone Desulfurization device of traditional single tower structure; Step c, the exhanst gas outlet at the top of the circulating absorption tower in the Wet Limestone Desulfurization device of traditional single tower structure is communicated with the secondary circulating flue gas entrance at secondary circulating absorption tower middle part, the secondary at the secondary circulating absorption tower top clean exhanst gas outlet that circulates is communicated with exit flue, and the circulating absorption tower in the Wet Limestone Desulfurization device of single tower structure that this moment is traditional becomes the one-level circulating absorption tower; Steps d, absorbent supply section, slurries oxidizing and crystallizing part and gypsum slurries dehydration part are set.
In described steps d, the gypsum slurries Returning outlet is set, secondary circulation gypsum slurries returns pump and pipeline, make the gypsum slurries Returning outlet return pump by secondary circulation gypsum slurries and pipeline is communicated with one-level circulating absorption tower slurry pool.
In described steps d, plaster serum rotational flow outlet, secondary circulation plaster serum rotational flow pump, slurries circulation cyclone and pipeline are set, the plaster serum rotational flow outlet is communicated with the charging aperture of slurries circulation cyclone by secondary circulation plaster serum rotational flow pump and pipeline, and the discharging opening of slurries circulation cyclone is communicated with one-level circulating absorption tower slurry pool, secondary circulating absorption tower slurry pool by pipeline again.
Compared with prior art the present invention has following characteristics and beneficial effect: the present invention advanced person that possesses skills, and equipment is reliable, and the ratio of performance to price is high, and coal-fired sulfur is had the characteristics such as good adaptability.Its cardinal principle is the sulfur dioxide (SO that utilizes in twice of lime stone (CaO) front and back and the flue gas
2) reaction, be aided with simultaneously oxidation air, with sulfur dioxide (SO
2) catch and the final gypsum (CaSO that generates
4.2H
2O), twice sulfur dioxide (SO
2) the clearance stack, thereby reach a very high desulfuration efficiency, realize the reduction of discharging of sulfur dioxide and the purpose that purifies air.
Two circulating absorption towers in the desulfurizer of the present invention are relatively independent, the control of the cyclic process in two circulating absorption towers also is independently, avoid the mutual restriction between the parameter, course of reaction is optimized more, can adapt to fast coal type change and load variations.
Used after the present invention, flue gas through preliminary treatment, has reduced the content of dirt, HCL, HF in one-level circulation, is conducive to the secondary circulation and reaches high desulfurization efficiency.
Flue gas flow rate in the one-level circulating absorption tower among the present invention is controlled at 3.0~3.5m/s, and the PH of the gypsum slurries in the one-level circulating absorption tower slurry pool is controlled at 4.6~5.0, and the slurries stay cycle is controlled to be 5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours.The benefit of doing like this is, under sour environment, oxidation efficiency can be very high, can guarantee excellent calcium sulfite oxidation effect and sufficient gypsum crystallization time, be conducive to the dissolving of lime stone and the crystallization of gypsum, can improve gypsum qualitt, improve the gypsum dehydration rate, can access the very high gypsum of quality; Simultaneously, under sour environment, the oxidation air coefficient can reduce greatly, and the oxidation air consumption can be reduced, so can significantly reduce the power consumption of oxidation fan.
Flue gas flow rate in the secondary circulating absorption tower among the present invention is controlled at 3.3~3.8m/s, and the PH of the gypsum slurries in the secondary circulating absorption tower stock tank 33 is controlled at 5.8~6.4, and the slurries stay cycle is controlled to be 4~5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours.The benefit of doing like this is that high pH value can guarantee very high desulfuration efficiency, and can greatly reduce the recycle slurry liquid measure, reduces the circulating pump liquid-gas ratio, reduces energy consumption.
Sulfur method of the present invention is because adopted the two-stage absorption tower, so the volume of dump stock tank is less than the volume of the dump stock tank in traditional Wet Limestone Desulfurization technology.
The independent control of each circulation of sulfur method of the present invention is easy to optimize and rapid adjustment, can adapt to the significantly variation of sulfur content and load, and the adaptive capacity of traditional Wet Limestone Desulfurization technology is less.
Traditional Wet Limestone Desulfurization technology all adopts the desulfurization of single tower single cycle, has that the absorption tower height is high, the capacious shortcoming of stock tank, is the two-stage absorption tower and the present invention adopts, so their height is lower, the stock tank volume is little, takes up room little.
Traditional Wet Limestone Desulfurization technology all adopts the desulfurization of single tower single cycle, only has a stock tank, so should obtain high-quality gypsum, obtain again high desulfurization efficiency, can make the control of plasm PH value become a contradiction, be difficult to reach balance, therefore generally can only satisfy a requirement, and sulfur method of the present invention can obtain high-quality gypsum, can obtain high desulfurization efficiency again.
Traditional Wet Limestone Desulfurization technology all adopts the desulfurization of single tower single cycle, and the desulfurization of single tower single cycle can only be selected single anticorrosion material, and every tower in the sulfur method of the present invention can be selected different suitable anticorrosion materials according to different PH.
The present invention is a kind of novel Wet Limestone Desulfurization technology, can on the basis of the Wet Limestone Desulfurization device of traditional single tower structure, form by capacity-increasing transformation, its advantage have following some.1, in the capacity-increasing transformation process, can take full advantage of the relevant device of original desulfurizer, avoided tearing open the least favorable situation that tower weight is built.2, in the capacity-increasing transformation process, in the situation that do not change desulfurizing agent, can effectively improve desulfuration efficiency, strengthen transforming contacting of newly added equipment and existing equipment, improved the reliability of whole desulphurization system, reduce cost.3, in the capacity-increasing transformation process, normal influence on system operation to existing desulfurizer is less, the idle time of existing desulfurizer is shorter, and desulphurization system can be moved continually and steadily after transforming, and the start and stop of desulphurization system and normal operation all do not affect the safe operation of unit and carrying out production strictly in line with rules and regulations of power plant.
The specific embodiment
Embodiment is referring to shown in Figure 1, and the two circulation Wet Limestone Desulfurization devices of this double tower comprise gas cleaning part, absorbent supply section, slurries oxidizing and crystallizing part and gypsum slurries dehydration part.
Described gas cleaning part is made of one-level circulating absorption tower 1 and secondary circulating absorption tower 2, and the one-level circulating flue gas at one-level circulating absorption tower 1 top outlet 26 is communicated with the secondary circulating flue gas entrance 27 at secondary circulating absorption tower 2 middle parts through transmitting flue 29, and the secondary at the secondary circulating absorption tower 2 tops clean exhanst gas outlet 28 that circulates passes through exit flue 34 and is communicated with atmosphere.
The inside hypomere of described one-level circulating absorption tower 1 has one-level circulating absorption tower slurry pool 32, epimere has one-level circulating absorption tower spraying layer 5 and one-level circulation demister 7, and one-level circulation demister 7 is positioned at the top of one-level circulating absorption tower spraying layer 5, the one-level circulation circulation line 23 that the shower of one-level circulating absorption tower spraying layer 5 connects outward is connected with one-level circulating absorption tower slurry pool 32, is connected with one-level circulation circulating pump 3 on this one-level circulation circulation line 23.
The inside hypomere of described secondary circulating absorption tower 2 has secondary circulating absorption tower slurry pool 33, epimere has secondary circulating absorption tower spraying layer 6 and secondary circulation demister 8, and secondary circulation demister 8 is positioned at the top of secondary circulating absorption tower spraying layer 6, the secondary circulation circulation line 24 that the shower of secondary circulating absorption tower spraying layer 6 connects outward is connected with secondary circulating absorption tower slurry pool 33, is connected with secondary circulation circulating pump 4 on this secondary circulation circulation line 24.
Described absorbent supply section is made of lime stone slurry case 17, lime stone slurry supply pump 18 and flow inlet road 31, and the discharging opening of lime stone slurry case 17 is communicated with one-level circulating absorption tower slurry pool 32, secondary circulating absorption tower slurry pool 33 by lime stone slurry supply pump 18 and flow inlet road 31.
Described slurries oxidizing and crystallizing part is made of oxidation fan 16, one-level circulating absorption tower oxidation spray gun 11, secondary circulating absorption tower oxidation spray gun 12 and oxidation air pipeline 30, and oxidation fan 16 is communicated with one-level circulating absorption tower slurry pool 32 by oxidation air pipeline 30 and one-level circulating absorption tower oxidation spray gun 11, and oxidation fan 16 is communicated with secondary circulating absorption tower slurry pool 33 by oxidation air pipeline 30 and secondary circulating absorption tower oxidation spray gun 12.That is to say, oxidation fan 16 passes into respectively the inside of one-level circulating absorption tower slurry pool 32 and the inside of secondary circulating absorption tower slurry pool 33 via oxidation air pipeline 30 and by one-level circulating absorption tower oxidation spray gun 11 and secondary circulating absorption tower oxidation spray gun 12 with air.
Described gypsum slurries dehydration part is made of one-level circulation gypsum excavationg pump 13, gypsum cyclone 14 and vacuum dehydration belt feeder 15; Described one-level circulating absorption tower slurry pool 32 is provided with the gypsum slurries outlet, and the gypsum slurries outlet is connected with the charging aperture of pipeline with gypsum cyclone 14 by gypsum excavationg pump 13, and the discharging opening of gypsum cyclone 14 is communicated with the charging aperture of vacuum dehydration belt feeder 15 again.
Described secondary circulating absorption tower slurry pool 33 is provided with the gypsum slurries Returning outlet, and the gypsum slurries Returning outlet returns pump 20 by secondary circulation gypsum slurries and pipeline is communicated with one-level circulating absorption tower slurry pool 32.It is the liquid level equilibrium of control one-level circulating absorption tower stock tank 32 and secondary circulating absorption tower slurry pool 33 that the purpose that gypsum slurries Returning outlet and secondary circulation gypsum slurries return pump 20 is set.
Described secondary circulating absorption tower slurry pool 33 is provided with the plaster serum rotational flow outlet, and the plaster serum rotational flow outlet is communicated with the charging aperture of slurries circulation cyclone 22 by secondary circulation plaster serum rotational flow pump 21 and pipeline, and the discharging opening of slurries circulation cyclone 22 is communicated with one-level circulating absorption tower slurry pool 32, secondary circulating absorption tower slurry pool 33 by pipeline again.The purpose that plaster serum rotational flow outlet, secondary circulation plaster serum rotational flow pump 21 and slurries circulation cyclone 22 are set is to control the serum density balance of one-level circulating absorption tower stock tank 32 and secondary circulating absorption tower slurry pool 33.
Be provided with one-level circulating absorption tower agitator 9 in the described one-level circulating absorption tower slurry pool 32, be provided with secondary circulating absorption tower agitator 10 in the secondary circulating absorption tower slurry pool 33.
This two circulation Wet Limestone Desulfurization methods of double tower of having used the two circulation Wet Limestone Desulfurization devices of above-mentioned double tower, its step is as follows.
Steps A, the former smoke inlet 25 of former flue gas through one-level circulating absorption tower 1 middle part enters one-level circulating absorption tower 1 inside, flue gas flow rate is controlled at 3.0~3.5m/s, gypsum slurries in the one-level circulating absorption tower stock tank 32 is delivered in the shower on the one-level circulating absorption tower spraying layer 5 by one-level circulation circulating pump 3 and one-level circulation circulation line 23, then former flue gas is washed and falls in the one-level circulating absorption tower stock tank 32, the pH value of the gypsum slurries in this one-level circulating absorption tower stock tank 32 is controlled at 4.6~5.0, the slurries stay cycle is controlled to be 5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours, this process can remove in the former flue gas 30%~80% SO
2
Step B, flue gas behind the once washing is upwards through 7 demists of one-level circulation demister, enter secondary circulating absorption tower 2 inside through transmitting flue 29 again, flue gas flow rate is controlled at 3.3~3.8m/s, gypsum slurries in the secondary circulating absorption tower stock tank 33 is delivered in the shower on the secondary circulating absorption tower spraying layer 6 by secondary circulation circulating pump 4 and secondary circulation circulation line 24, then the flue gas behind the once washing is carried out secondary washing and fall in the secondary circulating absorption tower stock tank 33, the pH value of the gypsum slurries in this secondary circulating absorption tower stock tank 33 is controlled at 5.8~6.4, the slurries stay cycle is controlled to be 4~5 minutes, CaCO
3Dissolution time be controlled at more than 30 minutes, the crystallization time of gypsum was controlled at more than 12 hours, this process can remove and remain SO in the flue gas
290%-97%.
Flue gas after step C, the secondary washing is upwards through 8 demists of secondary circulation demister, removes behind the large drop again by exit flue 34 qualified discharges.
Gypsum slurries in step D, the one-level circulating absorption tower stock tank 32 also is delivered to gypsum cyclone 14 by one-level circulation gypsum excavationg pump 13, then eddy flow is delivered to 15 dehydrations of vacuum dehydration belt feeder after concentrated again, does like this can finally obtain moisture content less than 10% gypsum crystal.
When carrying out steps A, step B, step C, gypsum slurries in the secondary circulating absorption tower slurry pool 33 also returns pump 20 by secondary circulation gypsum slurries and is delivered in the one-level circulating absorption tower stock tank 32, and the purpose of doing like this is to control the liquid level equilibrium of one-level circulating absorption tower stock tank 32 and secondary circulating absorption tower slurry pool 33.
When carrying out steps A, step B, step C, gypsum slurries in the secondary circulating absorption tower slurry pool 33 is delivered to slurries circulation cyclone 22 by secondary circulation plaster serum rotational flow pump 21, then eddy flow is concentrated by be delivered to respectively one-level circulating absorption tower stock tank 32, secondary circulating absorption tower slurry pool 33 by pipeline, and the purpose of doing like this is to control the serum density balance of one-level circulating absorption tower stock tank 32 and secondary circulating absorption tower slurry pool 33.
Take certain test as example: the present invention is applied to the flue gas desulfurization test of 2*300MW unit, original slurries circulating absorption tower before wherein one-level circulating absorption tower or secondary circulating absorption tower can utilize and transform, every stove one cover desulfurizer, transform idle time less than one month, main operational factor is as follows: 1. SO in the former flue gas
2Mass concentration is 10947mg/ Nm
3(mark dry state, 6%O
2), clean flue gas SO
2Mass concentration is 142.3mg/m
3(mark dry state, 6%O
2), desulfuration efficiency is 98.7%; 2. former flue-gas temperature is 132 ℃, and clean flue-gas temperature is 53.2 ℃; 3. finished product gypsum moisture content is 7.52%.From the test run effect, the two circulation Wet Limestone Desulfurization methods of double tower of the present invention can reach very high desulfuration efficiency.Compare existing fume desulphurization method, obtain that the power consumption that same desulfuration efficiency consumes is low, the quality of gypsum wants high.
The preparation method of the two circulation Wet Limestone Desulfurization devices of above-mentioned double tower (being the method that a kind of Wet Limestone Desulfurization plant modification with traditional single tower structure becomes the two circulation Wet Limestone Desulfurization devices of double tower), its step is as follows.
Step a, a newly-built circulating absorption tower with spraying layer and demister make this circulating absorption tower as secondary circulating absorption tower 2.
Step b, remove the exhanst gas outlet at top and being connected of exit flue of the circulating absorption tower in the Wet Limestone Desulfurization device of traditional single tower structure.
Step c, the exhanst gas outlet at the top of the circulating absorption tower in the Wet Limestone Desulfurization device of traditional single tower structure is communicated with the secondary circulating flue gas entrance 27 at secondary circulating absorption tower 2 middle parts, the secondary at the secondary circulating absorption tower 2 tops clean exhanst gas outlet that circulates is communicated with exit flue 34, and the circulating absorption tower in the Wet Limestone Desulfurization device of single tower structure that this moment is traditional becomes one-level circulating absorption tower 1.
Steps d, absorbent supply section, slurries oxidizing and crystallizing part and gypsum slurries dehydration part are set.The gypsum slurries Returning outlet is set simultaneously, secondary circulation gypsum slurries returns pump 20 and pipeline, makes the gypsum slurries Returning outlet return pump 20 by secondary circulation gypsum slurries and pipeline is communicated with one-level circulating absorption tower slurry pool 32.Plaster serum rotational flow outlet, secondary circulation plaster serum rotational flow pump 21, slurries circulation cyclone 22 and pipeline also are set simultaneously, the plaster serum rotational flow outlet is communicated with the charging aperture of slurries circulation cyclone 22 by secondary circulation plaster serum rotational flow pump 21 and pipeline, and the discharging opening of slurries circulation cyclone 22 is communicated with one-level circulating absorption tower slurry pool 32, secondary circulating absorption tower slurry pool 33 by pipeline again.