CN1153482A - Improved wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents - Google Patents
Improved wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents Download PDFInfo
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- CN1153482A CN1153482A CN 95194199 CN95194199A CN1153482A CN 1153482 A CN1153482 A CN 1153482A CN 95194199 CN95194199 CN 95194199 CN 95194199 A CN95194199 A CN 95194199A CN 1153482 A CN1153482 A CN 1153482A
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Abstract
The method is more effective and more economical in respect of the capital and operational costs for scrubbing of exhaust gases after burning from sulphur oxides (SOx) with hydrous lime-stone suspensions. In single-passage open anticurrent lime-stone wet gas scrubbing towers the velocities of the flue gases flow are increased considerably, whilst the values of the liquid/gas ratio and the time of staying in the reactor tank are reduced. These advantages are also ensured from a drip pan separator of improved design, new arrangement and a step between the nozzles and the employment of a hydrocyclone which separates and recycles the minute particles of limestone from the gypsum turned out as a byproduct. The limestone is in the form of very fine particles, e. g. under 8 , and in more than 99% of the total amount particles smaller than 44, is used as scrubber suspension in contact with the SOx-containing exhaust gas. The reactivity of the scrubber suspension, even in lowered pH value, is maintained by a permanently operating hydrocyclone ensuring molar ratio of the calcium-containing to the sulphur-containing compositions larger than 1.3. At the same time low chloride and inert solid particles content is maintained. The hydrocyclone removes the larger-size calcium sulphate particles and ensures recirculation flow of fine calcium carbonate and inert solid particle flow which is discharged, if needed, in order to maintain the required low content of chlorides and inert solid substances.
Description
The present invention relates to remove sulfur oxide (SO in the burnt gas
x) improvement, it has higher efficient and investment and the operation cost is all more economical.
The burning of the considerable carbonaceous material of sulfur content such as fossil fuel and refuse worldwide just is being subjected to the strictness control of government.The burning of these materials can cause the atomic group combination at high temperature of sulphur and oxygen, generates various sulfur oxides, and they are the SO of indication just
xMany countries also implement various rules and reduce the sulfur oxide that is discharged in the atmosphere, thereby alleviate the problem relevant with acid rain.
At present, just taking multiple strategy to reduce the SO that is discharged in the atmosphere
x, it has the method for removing sulphur in the fuel before burning; Use the method for chemical method " passivation " sulphur in the combustion process; With the method for from burnt gas, removing sulfur oxide.These treatment of combustion flue gas are removed SO
xMethod be that wet method or dry method are cleaned.The wet-cleaning technical development is good, and is also very effective; Yet, need the very big proportional rising of equipment cost.
Eliminate SO in the burnt gas with wet-cleaning
xTechnology the solution-air contact of multiple different structure form is provided.The topmost tower that single cycle and two circulation upstream injection tower is arranged and adopt following current and countercurrent zone.
Adopt calcium carbonate and SO
xSingle cycle, the open type Tower System of reaction are the simplest in structure and operating aspect.The common optimised employing of these systems because their in when operation pressure reduce, and the trend of fouling or obstruction of producing is little.Yet their better way advantages are offset by their large-size in some occasion.For example, because they adopt any tower tray or filler to improve waste gas and clean contact between the tower, tower height is very high usually, and adopts the multilayer nozzle to guarantee excellent contact.
In the open type spray tower, cleaning fluid absorbs SO from gas
xAbility depend on the effective alkalinity of liquid.On the most effective source of wet-cleaning system neutral and alkali is common is calcium carbonate.Yet, improving with the alkalescence of washing lotion, the solubility property of calcium carbonate descends usually.The tower that has filler and tower tray improves absorption by making calcium carbonate in the solution-air contact zone stop long period, thereby provides mechanism for dissolving more, and the result just can use cleaning fluid more efficiently.On the other hand, the open type spray tower designs higherly usually, thereby be provided long as far as possible time of contact, uses a plurality of jetted layers so that most effectively cleaning fluid is introduced in the tower usually.
People wish improve to adopt calcium carbonate to handle to contain SO
xThe single cycle of burnt gas, open type tower wet-cleaning promptly by improving process efficiency, and the corresponding high processing benefit of bringing, reduces the appearance and size of tower simultaneously; Improve the utilization rate of calcium carbonate, keep high reliability, reduce energy consumption; With obtain high productivity ratio and high SO
xReducing percentage realizes.
People also wish to adopt calcium carbonate to handle to contain SO by not relying on chemical addition agent to improve to clean the method for the respond of slurry, improving
xSingle cycle, the open type tower moisture ablution of burnt gas.
Rader and Bakke have discussed design and the operation of adopting the single cycle upstream injection tower of lime stone in " Incorporating Full-Scale Experience Into AdvancedLimestone Wet FGD Designs " literary composition, what deliver on this paper IGCI Forum91 that to be on September 12nd, 1991 hold in the Washington D.C. (was that industrial waste gas cleans association in the past, be clean air Gesellschaft now, in the Washington D.C.).Open type spray tower (just, those do not have filler, and tower tray and other are realized the tower of gas-liquid contact device) design is got up very simple, and high reliability can be provided.They are used in particular for coal fired power plant, and wherein muriatic generation and development have brought some problems, and it comprises: reduced the respond of cleaning fluid and to cleaning the heavy corrosion of tower inside.Like utilizing another factor of open type tower to be low pressure drop and the thing followed blower fan dynamic economics that they are intrinsic.
The someone advises using various reactants, still, best reactant be those use very effective, do not need high interpolation layer, low price, storage and transportation not to have the reactant of specific (special) requirements again.Calcium carbonate (various ways is arranged on the market, comprise lime stone) is a kind of selectable material, because it satisfies these requirements.When suitably handling, the process byproducts of generation is landfill disposal simply, or is used as gypsum and sells.
The sort of single cycle, adverse current, open type in Rader and Bakke discussion are cleaned in the tower, and the cleaning fluid of calcium carbonate-base flows downward, and contains SO
xWaste gas upwards flow.They have summed up empirical value for some parameters, comprise that (provided minimum of a value is 6 feet per seconds to the speed that absorbs gas, maximum is 15 feet per seconds, just about 2 meter per seconds arrive less than between 5 meter per seconds), it is very little to the influence of liquid-gas ratio example (L/G) to indicate the speed that absorbs gas, and L/G is than a key factor that is investment and operation cost.In these towers, the height of injection contact zone does not provide, but typical value is removed at least 95% SO 6～15 meters magnitude reliably one of design is expected to give up from burning
xEfficient system the time, it is considered to an important factor always.
In such existing tower, the ratio of slurries amount and gas flow (L/G) is considered to unique most important design parameter, L/G cost and other operation and the economic factor than the cost that influences pump, pans.The cost of pumping lime white and the height of tower are proportional.Preferably reduce the requirement of L/G and the height of attenuating open type spray tower.
Sulfur oxide (SO
x), mainly be SO
2, be absorbed into and clean in the slurry, and collect in the retort, form solid-state calcium sulfite and solid-state calcium sulfate here.Best, oxygenation in the retort is to force to generate sulfate.In case vitriol is long to enough big, separates in their slurries from retort.
One piece of " THE BISCHOFF FLUE GASDESULFURIZATION PROCESS " (Bischof process waste gas process for sulfur removal by name being shown at K.R.Hegemann etc., deliver in first waste gas sulphur removal jointly hosting by EPA and EPRI on October 25th～28,1988 and the sulfur dioxide control associating seminar) paper in, introduced a kind of cleaning tower, it comprises a hydrocyclone circulation, this circulation handle is from one calcium plaster in the wet-cleaning tower, be separated into one thick efflux of solids and one thin efflux of solids, and thin efflux of solids is sent back in the cleaning tower.At U.S. Pat No.5,215, in 672, Rogers etc. have introduced a similar technical process of being introduced with Hegemann etc., wherein, it adopts a hydrocyclone to be used as a main dehydrator, under latter event, after from the thick efflux of solids that is rich in gypsum, isolating thin efflux of solids, water as the part of multiviscosisty thread is handled, simultaneously, remove at least a portion thread, yet two kinds of methods all do not show how to adopt hydrocyclone to improve entire process efficient and corresponding higher processing benefit and reduce the overall dimensions requirement of tower when the dehydrator of deciding, improve the utilization of reactant, keep high reliability, reduce energy consumption, and obtain high productivity ratio and high SO
xLower percentage.
This technology also provides packed tower, though Radar and Bakke point out that with regard to some advantage that reduced cost, there is other danger in such tower simultaneously.Filler and other solution-air mixing arrangement may stop up or corrode, and cause beyond thought bypass or pressure to fall, and cause the prolongation of downtime.Best, adopt a kind of open type tower, the advantage that it has packed tower does not but need filler, and littler than the open type tower of existing structure.
Prior art does not directly point out to obtain the required technical essential of following improvement, is being used to reduce SO
xSingle cycle, open type tower, adverse current lime stone moisture clean tower, its effect can compare favourably with the effect of packed tower gained, but without filler, also the problem relevant with it not.
Clean in the tower in the sort of single cycle, adverse current, open type that Rader and Bakke discussed, the cleaning slurry that comprises calcium carbonate, calcium sulfate, calcium sulfite and other non-reaction solid flows downward, and simultaneously, contains SO
xWaste gas upwards flow.SO
x, mainly be SO
2, be absorbed in the cleaning slurry of decline, collect in the retort, form calcium sulfite and calcium sulfate at this.Best, oxygenation in the retort is forced from calcium sulfite generation calcium sulfate.In case the sulfide crystal is long to enough big, they take away from retort and separate from slurries.Return molten impurity,, also be drawn out of as chloride.These tower manufacturings and operation are got up both economical, but the respond of cleaning slurry is depended in the cost aspect these two.On the practical work, these costs are subjected to cleaning the adverse effect of the chloride concentration of the high dissolution in the slurry, and it has suppressed the respond of calcium carbonate.
People know that adopting blowdown stream to reduce cleans muriatic content in the slurry.Typically, resulting recycle-water during blowdown stream reclaims from retort or from gypsum in the technical process.
For example, at U.S. Pat No.3, Downs etc. absorbs from one and extracts slurries out the storage tank in 995,006, and it is delivered in the hydrocyclone, isolates the stream that one is rich in thin calcium sulfite particles from one is rich in the stream of bigger calcium carbonate granule.After separating the second time of calcium sulfite, give off one multiviscosisty that contains calcium sulfite stream.In most of the cases, give off a large amount of water in this way and come muriatic gathering in the control system.Yet,, do not wish to discharge a large amount of water from environment and economic angle.
At U.S. Pat No.5, Rogers etc. has introduced the similar treatment process that a kind of and Downs etc. are introduced in 215,672, wherein, it adopt a hydrocyclone from by with from burnt gas, clean under SO
xIsolate non-reactive calcium carbonate in the calcium salt that reacts and form.In this case, isolate the thick efflux of solids that is rich in gypsum from one after one thin efflux of solids, when having at least a particulate to be pulled away, water is handled as the part of multiviscosisty thread.If enough water is pulled away, come blowdown to be enough to muriatic accumulation in the control system so in this way, this method can be removed a high proportion of particulate amount.Rogers etc. make every effort to these particulates are used as waste disposal.Yet, from introduction of the present invention, can obviously find out, revise this strategy, still discharge a certain proportion of water simultaneously and control chloride, can help the respond in the increase system.
Step in the 93rd phase chimney exhaust control bimonthly report of group of Consultation Center (the 93 rd Bimonthly Report of the Stack Gas Emissions Control CoordinationCenter Group) article in July, 1989 Rosenberg and Koch one piece, a hydrocyclone circulation of installing in a FGD of Holland (exhuast gas desulfurization flue gasdesulfurization) factory, introduced as Rogers etc., one is isolated one thick efflux of solids and one thin efflux of solids from the calcium plaster that moisture cleans tower, allow all thin efflux of solids turn back to and clean in the tower.By moving in this way, not blowdown from this plume, but must be in other local blowdown.Artwork shown in Figure 2 in this article is expressed, from a vacuum belt filter blowdown.Chloride is controlled in this point place draining in technical process, but it takes away the water yield more than requirement by this method, dilutes because the water of draining like this is used to wash the fresh supplemented water of gypsum.
Be used to reduce SO
xSingle cycle, open type tower, adverse current limestone wet-process clean in the tower, prior art is not directly pointed out the required technical essential of realization response ability improvement.
An object of the present invention is to be wet-cleaning waste gas,, provide improved method and apparatus to remove sulfur oxide particularly from the waste gas of coal-burning boiler.
Another purpose of one embodiment of the present invention provides the improved SO that is used to reduce
xSingle cycle, open type tower, adverse current limestone wet-process clean tower.
Another object of the present invention is to make single cycle, open type tower, adverse current limestone wet-process clean the state that tower runs on low L/G value.
Still a further object of the present invention is the size that reduces single cycle, open type tower, adverse current limestone wet-process cleaning tower.
It is to increase the exhaust flow velocity that gas cleans tower through single cycle, open type tower, adverse current limestone wet-process that the present invention also has specific purposes.
The present invention's another purpose again is to improve design and the position that single cycle, open type tower, adverse current limestone wet-process are cleaned separator and demister in the tower, thus effectively to waste gas demist through cleaning, and with its direction from cleaning the cat head turn-off of tower.
The present invention's another purpose again is to improve single cycle, open type tower, adverse current limestone wet-process cleaning tower, reduces the holdup time of gypsum crystal in cleaning tower, and can use hydrocyclone that they are separated from littler limestone particle.
Another purpose of one embodiment of the present invention be from reduce gypsum crystal during cleaning tower holdup time and utilize hydrocyclone remain on operation under high calcium and the sulphur equivalent proportion state, simultaneously promote efficiently to utilize calcium carbonate aspect improve the operation of single cycle, open type tower, adverse current limestone wet-process cleaning tower.
Another purpose of the preferred embodiment of the present invention is by using less jetted layers to realize contact between effective liquids and gases at the cleaning area of the height that reduces, and improves the operating procedure efficient that single cycle, open type tower, adverse current limestone wet-process are cleaned tower.
It is that minimally reduces undressed gas throughput and obtains the mode that effective solution-air contacts with less nozzle by the arrangement that improves nozzle that one embodiment of the present invention also has a purpose in addition, improves the operation of single cycle, open type tower, adverse current limestone wet-process cleaning tower.
One embodiment of the present invention have more in addition a purpose be by keep cleaning slurry high respond, improve the utilization of lime stone and overall improvement on the treatment effeciency be provided, improve the operation that single cycle, open type tower, adverse current limestone wet-process are cleaned tower.
Further object of the present invention is to be used for removing the operation that muriatic device improves single cycle, open type tower, adverse current wet-cleaning tower from cleaning fluid by employing.
The present invention has realized these purposes and other purpose, and it particularly resembles the fuel of coal and the such sulfur-bearing of solid waste for wet-cleaning the cleaning of burnt gas provides improved method and apparatus.
On the one hand, the present invention has improved and has been used for reducing waste gas SO
x(mainly be SO
2) the wet stone method cleaning method of single cycle, open type tower, adverse current lime base of concentration.On the other hand, the invention provides a kind of above-mentioned improved device that reaches, will describe in detail it below.To sum up, this method comprises: (a) guiding contains SO
xWaste gas stream with greater than 4.5 meter per seconds, the bulk velocity that preferably can arrive 6 meter per seconds is vertically cleaned tower by one and is upwards flowed; (b) the water pulping liquid droplets of introduction calcium carbonate in small, broken bits, calcium sulfate, calcium sulfite and other non-reaction solid in a vertical cleaning area of above-mentioned tower, calcium carbonate preferably has 6 μ or littler weighted average particle diameter (weight median diameter), calculate by weight 99% particle less than 44 μ, and the mol ratio of the compound of the compound of calcic and sulfur-bearing is at least 1.1 to 1.2 in the solid, contacts with waste gas when the contrary waste gas flow path direction of these liquid droplets lands downwards by tower; (c), the liquid slurry is collected in the retort with after gas contacts; (d) Extract slurry from retort is preferably extracted out later at 8 hours or still less mean residence time; (e) the liquid slurry of extracting out is carried out processed from retort, preferably in a hydrocyclone, carry out, thereby a circular flow is provided, and it comprises a hydrocyclone overflow of being rich in thin calcium carbonate granule, and the overall mol ratio of calcium containing compound and sulfur-containing compound is at least 1.3; With another stream, it comprises a hydrocyclone underflow that is rich in calcium sulfate particle, and preferably the weighted average diameter of calcium sulfate particle (f) is advanced the circular flow foldback that is rich in calcium carbonate in the processing procedure between about 25～about 55 μ; And (g) in system, introduce new calcium carbonate and other non-reaction solid as feed, its quantity be enough to remedy be drawn out of and not have to utilize and dissolved and with the SO that in cleaning tower liquid phase, absorbs
xThe calcium of reaction, above-mentioned introducing calcium carbonate granule weighted average in small, broken bits size is less than 10 μ.
Preferably the liquid slurry is introduced from jet blower, and nozzle is staggered in direction up and down on the jetted layers of about 1-2 rice at two.The whole tower height that is preferably in the injection contact zone is less than about 6 meters, and preferably height is less than about 4 meters, because confirmed elimination 95% or more SO from burnt gas
x, tower height is not important like that.The diameter that an advantage of the invention is tower can be less, thereby, only calculating and ignore injector head and the shared area of nozzle by cross-sectional area, waste gas vertically is no less than 4.5 meter per seconds by the overall operation speed of spraying the contact zone, preferably to 6 meter per seconds.This higher speed provide a kind of in tower the mode of suspension liquid, and do not need to increase tower height, also not needing increases filler and tower tray for containing the carrier fluid body, and the liquid that suspends like this is owing to increased the time of dissolving calcium carbonate, so have more reagency.So obvious advantage of the present invention is to have increased the time of contact of tower and the height that do not increase tower, also keeping the simplicity of design, construction, operation and the maintenance of open type spray tower simultaneously.
In more preferred embodiment, the mean size of calcium carbonate is maintained at about between about 6 μ of 2-in the retort, and the calcium carbonate weighted average granular size of being introduced is less than about 8 μ, and the particle of calculating by weight at least 99% (as 99.5%) is less than 44 μ.
All adverse current open type towers, packed tower or the tower that has a tower tray preferably clean the mol ratio height of the compound of the compound of calcic in the solid phase of slurry and sulfur-bearing.This mol ratio higher position can be useful on removes SO
xStronger alkalescence, so, improved liquid absorption capacity.Yet in present treatment process, this mol ratio height is uneconomic, because the compound of expensive calcic specifically is meant calcium carbonate, will be wasted with the compound of removing sulphur by dewatering system.The present invention allows the following cleaning slurry of utilization in spray tower, and economically viable concentration is much higher in other system of the concentration ratio of its solid-state calcium carbonate.When using the preferential granular size that adopts contact with solution-air, the relative concentration of hydrocyclone effective calcium in increasing jar and alkaline aspect be effectively.
In a preferred embodiment, clean in the tower and comprise at least one first separator (entrainmentseparator), be used to remove the mist carried secretly in a large number and the direction of waste gas is turned at least 30 ° from vertical axes.In the preferential embodiment that adopts, diameter is less than most of drop of 100 μ or by allowing them fall from waste gas, or the method that allows their cohesions form the larger particles that can remove easily with a downstream demister is removed.There is the demister of an approximate vertical the best first separator back.
On the other hand, the invention provides a kind of waste gas SO that is used for reducing
xThe improvement wet scrubbing method of concentration, it comprises: (a) guide exhaust gas flow upwards flows by a cleaning tower; (b) introduce calcium carbonate in small, broken bits, calcium sulfate, calcium sulfite and the water of non-reaction solid and become jetting slurry, its contrary airflow direction passes tower and lands downwards; The weighted average diameter of calcium carbonate granule is between about 2～about 6 μ; (c) with after waste gas contacts, the liquid slurry is collected in the retort; (d) Extract slurry from retort, and in a hydrocyclone, it is handled, and form two plumes, be rich in the fine grained of calcium carbonate and non-reaction solid in one circular flow, another plume is rich in calcium sulfate, all contains the chloride of dissolving in above-mentioned two plumes, will discharge with a part that is rich in the circular flow of calcium carbonate and non-reaction solid as the calcium sulfate of solid, thereby remove the chloride and the non-reaction solid of dissolving, keep the high respond of liquid slurry in this way; (f) introduce new calcium carbonate as feed in system, its quantity is enough to remedy because the calcium carbonate that the circular flow discharge of the separation of above-mentioned calcium sulfate and above-mentioned part is taken away, and the weighted average granular size of the calcium carbonate in small, broken bits of above-mentioned introducing is less than about 10 μ.
Above-mentioned treatment process method also can be moved under the pH value that improves respond, and preferably, the pH value of liquid slurry is preferably between about 5.8～about 6.3 between about 5.0～about 6.3 in the retort.
Desirable is that the mol ratio of the compound of the compound of calcic and sulfur-bearing should keep greater than 1.3, more preferably greater than 1.4 in the circular flow.In addition, keep the concentration of suspended solid in the circular flow should be less than about 15%, preferably less than about 5%.Preferably, this method also comprises following each step, determines the content of chlorine compound in the liquid slurry, then gives off a part of circular flow if this value surpasses a predetermined maximum chloride concentration.Be more preferably, this method also comprises following each step, determines the concentration of solid in the circular flow, and as long as solid concentration surpasses an expectant control value, just discharges a part of circular flow.In this last mode, the content of non-reaction solid is controlled.
On the other hand, the invention provides a kind of improved waste gas SO that is used for reducing
xThe wet-cleaning device of concentration, it comprises: (a) cleaning tower, it comprises a gas access flue, a gas vent flue and a vertical cleaning area, contains SO in order to guiding
xWaste gas stream upwards flow by above-mentioned cleaning area; (b) injection apparatus array that is positioned at cleaning area, this array becomes jetting slurry in order to introduce calcium carbonate in small, broken bits, calcium sulfate, calcium sulfite and the water of non-reaction solid, and its contrary waste gas stream lands downwards by tower; (c) retort, it is positioned under the above-mentioned injection apparatus array, and it can contact a period of time to collect the liquid slurry afterwards with waste gas in above-mentioned vertical cleaning area, and the size of above-mentioned retort is fit to allow SO
xForm following gypsum crystal with calcium carbonate reaction, its weighted average particle diameter is the twice as the calcium carbonate granule diameter of feed adding at least; (d) in described retort as the device of feed supply calcium carbonate, the weighted average diameter of calcium carbonate is less than about 10 μ, at least 99% particle is less than about 44 μ; (e) device that jetting slurry is provided, it comprises at least one pump and duct coupling, starches in the above-mentioned injection apparatus array that is sent in the above-mentioned cleaning area in order to the slurry of Extract from retort with liquid; (f) liquid slurry quality keeps system, and it comprises that one is separated into the hydrocyclone of two plumes to the above-mentioned liquid slurry in the above-mentioned retort, and this two plume is rich in the fine grained of calcium carbonate and non-reaction solid and bigger calcium sulfate particle respectively; Be used for delivering at least one pump and duct coupling the hydrocyclone from retort Extract slurry and with it; A circulating line, it connect above-mentioned hydrocyclone and above-mentioned retort and from above-mentioned hydrocyclone transmission be rich in the circular flow of calcium carbonate and non-reaction solid; A calcium sulfate recovery channel, it is drawn from above-mentioned hydrocyclone and drains the liquid that is rich in calcium sulfate and starch from above-mentioned hydrocyclone; With a blow-off line, it is connected with above-mentioned circulating line, and is used for discharging a part of circular flow of above-mentioned circulating line.
The weight and volume that a this improved effect is a tower is that present open type is cleaned the only about half of of tower.Both improved treatment effeciency, and also improved the processing benefit, simultaneously, the utilization of reactant also is improved, and has improved reliability, has reduced energy consumption, reaches high productivity ratio, and has reduced SO significantly
xContent.
By following introduction, particularly Xia Mian accompanying drawing just can be understood the present invention and advantage thereof better, and these accompanying drawings comprise:
Fig. 1 is the schematic diagram of the preferred embodiment of the inventive method, and it has adopted a single cycle, open type tower, adverse current limestone wet-process to clean tower;
Fig. 2 is the detail drawing of the cleaning tower of type shown in Figure 1;
Fig. 3 is the partial side view of nozzle arrangement in two jetted layers shown in Figure 2;
Fig. 4 is the nozzle bottom view that is used for two jetted layers of spray tower of type shown in Figure 2;
Fig. 5 is the perspective view of separator shown in Fig. 1 and Fig. 2 spray tower.
Improvement among the present invention preferentially is used in the civil boiler waste gas of making fuel with coal, and is in some aspects right The perchloride operation that resembles incinerator and so on is very effective. Although this advantage to the operation of the type the most Obviously, but the present invention is not limited to these application. Burnt gas from all types carbonaceous material all can To process, also comprise natural gas, synthesis gas, fuel oil, pitch and residual fuel oil, family or industrial solid Or other incendivity waste material, and the like material.
Concentrate below and introduce preferred embodiment shown in Figure 1, it is to be used for removing sulfur oxide from burnt gas, mainly is SO
2, single cycle, open type tower, adverse current limestone wet-process clean running.
Lime stone is the preferential employing form of calcium carbonate, still, if necessary, also can substitute with other form.Except lime stone, other form of calcium carbonate comprises oyster shell, cloud tints stone, calcite, chalk, marble, plaster and travertine.They can be exploited, and also can make.In this piece of writing was introduced, two terms of calcium carbonate and lime stone can change mutually.
Must be pointed out that importantly nearly all form that collects of the calcium carbonate that occurring in nature is found contains the material of a spot of comparatively inertia, as the oxide of elemental silicon, magnesium carbonate or dolomite, iron, aluminium oxide or the like.In principle, always wish to find very pure calcium carbonate for the limestone wet-process cleaning, still, in fact, often have some impurity, they form non-reaction solid in wet clean process.Other sources that enter the non-reaction solid in the processing procedure are to overflow from particle collector 10 and be trapped in the flying dust that cleans among the tower 100.
Agstone is broken into smalls, preferably utilizes following Ginding process, is 10 μ or littler and reach weighted average diameter, and wherein 99% below 44 μ.For the wet-cleaning in the open type tower with lime white adverse current, this powder is superfine.Commonplace grind size is that weighted average diameter is 15 μ or still less in the prior art, wherein is no more than 95% particle less than 44 μ.Do further relatively with prior art, as can be seen the preferential grind size that adopts of the present invention be the weighted average particle size less than 8 μ, wherein the particle of 90% (as 99.5%) uses the preferential granularity that adopts that some advantages are arranged less than 44 μ by weight.
The technological design of preferential employing shown in Figure 1 shows, exhaust gas discharged enters a device 10 that is fit to that is used to remove grit the civilian or Industrial Boiler from fire coal, and as electrostatic precipitator or fabric filter, device 10 is disposed entrained solids to a great extent.Enter wet-cleaning tower 100 through a flue 20 then through the contrary gas of dedusting, here gas upwards flows, and becomes jetting slurry formation adverse current by the water that contains the fine powder lime stone of discharging from two-layer nozzle in the vertical cleaning area 110.Waste gas continues to flow and process gas vent flue 120 from cleaning area 110.The structure guide exhaust gas flow of tower upwards flows by vertical cleaning area.The slurries that fall by vertical cleaning area 100 are collected in the retort 130.The size of retort 130 preferably can be suitable for allowing SO
2Generate the gypsum crystal of following granularity with calcium carbonate reaction, at least 2 times of its weighted average diameter are preferably 5～10 times to the calcium carbonate granule that adds as charging.
The difference that guarantees this granularity helps the preferred embodiment, it requires preferably to extract one slurries after about 6 hours mean residence time, and from calcium carbonate (become fine silt, preferably weighted average diameter is less than 6 μ) content, come the concentrate slurry and remove gypsum.
Vertically cleaning area 110 comprises an injection apparatus array that is positioned at wherein.The water that the structure of this array can be introduced fine powder calcium carbonate becomes the lime jetting slurry and contrary waste gas flows down.Show one group of nozzle among the figure, as shown in the figure, it comprises two-layer 112,112 ' nozzle.To each nozzle 114 (see figure 2) supply with from shower nozzle 116,116 ' or 116 " in the liquid slurry.Typically, also comprise the 3rd a layer of nozzle usually, and allow one deck have a rest repairing or cleaning, but have two-layer still in running.
Preferably between each layer of nozzle 1～2 meter spacing is arranged, and on certain one deck adjacent nozzle direction alternately up and down.The preferred embodiment of the present invention has reduced the spacing between the nozzle, reduces the number of plies that comes into operation whenever (being preferably 2 layers), has increased the speed that gas upwards flows along vertical cleaning area.The preferred form of the type of flow of the waste gas that has shown jetting slurry among Fig. 4 and upwards flowed along tower.
The preferential employing form of nozzle is a kind of rotarytype injector, and it forms a jetting slurry, and its angle [alpha] is preferably about 120 ° between about 90 °-Yue 140 °.A kind of suitable nozzle is the nozzle of Whirljet 300 gallon per minute, and it can have been bought from the Spraying System Co. of the Wheaton of Illinois.The drop size is preferably about 6000 μ of about 100-, is generally about 2000 μ, and its Sauter average diameter is measured by the Malvem grain analyser.
Shower nozzle on the framed bent of each shower nozzle 116 and next the upper and lower is angled, when adopting two-layer or three layers time, being preferably 90 °.
One of the present invention new with improved feature is, the commercial values of the holdup time in retort from common 15 hours or more hours was reduced to about 8 hours, typically was approximately 6 hours.This is by the rate of dissolution of the broken calcium carbonate granule of fine powder that improves and is brought by the speed of calcium sulfate precipitation faster that forms gypsum particle to a certain extent.Thus, isolate calcium sulfate in the calcium carbonate from liquid slurry and calcium carbonate is recycled into the slurries of the fine grained formula of very fast dissolving in retort, improve the respond of liquid slurry.The minimizing of holdup time has active influence to some advantages of the aspects such as quality of simplicity, instrument size and the by-produced gypsum of overall treatment efficiency and processing in retort.
The whole air velocity of the waste gas that flows by vertical cleaning area 110 preferably can reach about 6 meter per seconds greater than 4.5 meter per seconds.The application facet that this air velocity is cleaned in the tower for single cycle, open type tower wet method lime stone is very high, and preferably makes together by the present invention and other reform measure and be used for improving overall process efficiency.Preferred cleaning tower of the present invention can enough quite low pressure falls and the relative quantity of lower water pulping, recently handles waste gas as low L/G.
Sulfur oxide is absorbed in the liquid phase of liquid slurry in the waste gas, forms bisulfite ions and hydrogen ion.Some bisulfites is oxidized to sulfate, discharges more hydrogen ion simultaneously.When becoming saturated along with hydrogen ion in the drop, the dissolution velocity of calcium carbonate begins to accelerate, and forms calcium ion and bicarbonate.Fine powder calcium carbonate can absorb hydrogen ion very effectively, so improved the absorbability of liquid phase in the tower inlet zone.Used high gas flow speed among the present invention, and the preferential spray regime that adopts can make drop maintain certain fluidisation degree, and be contacted preferably.
Shown in Fig. 1, lime stone carries out fine grinding in a grinder 170, by a cyclone separator 172 classification, is collected in one bag of shape chamber (bag house) 174, and through an air-lock 176 meterings, enters the compressed air stream in the pipeline 178.Before just entering the cleaning tower lime stone is ground, the introducing retort can be prepared into very thin with the lime stone that replenishes calcium carbonate, wherein do not contain the bulky grain greater than 44 μ.In fact, the weighted average granularity that can obtain the dry-ground whiting particle generally speaking is less than 8 μ, and 99% or more particles less than 44 μ.Removing bulky grain the lime stone in retort is a key character, and it allows the used retort of the present invention little more many than used retort in the existing cleaning tower.
Air in the pipeline 178 provides oxygen for sulphite and bisulfite ions are oxidized to sulfate.The most handy existing apparatus of jar stirs, and does not show this device among the figure.
Method of the present invention is as shown in Figure 1 extracted slurries out and is concentrated the calcium carbonate that can react so that reclaim the content of using and reduce solid again on the other hand from retort 130, this mainly is to finish by removing gypsum.The slurry of liquid shown in Fig. 1 is to extract from retort 130 by pipeline 183, and is sent in the hydrocyclone 181.Hydrocyclone is of the present invention in service very effective, because it can be fast and effeciently the bigger calcium sulfate particle and the unusual lime stone of fine powder are separated.The weighted average diameter of calcium sulfate particle is preferably between about 25 μ-Yue 55 μ.Isolate that less limestone particle forms one circular flow that is rich in calcium carbonate 174 and one is rich in the discharge stream 176 of calcium sulfate.Preferably, in the retort and in the circular flow 184 the weighted average granular size of calcium carbonate between about 6 μ of about 2-.
Fig. 1 has shown the form of the preferred embodiment of the present invention, and wherein the content of calcium carbonate and useful processing water is improved in hydrocyclone 181 in the circular flow.Preferably the weighted average diameter of calcium carbonate granule is between about 6 μ of about 2-.The weighted average diameter of calcium sulfate particle is between about 55 μ of about 25-.
According to the difference of granular size between calcium carbonate and the gypsum, will introduce the device that is used to separate gypsum and concentrate calcium carbonate in detail below, the concentration that is reached in the counter-flow designs of the solid concentration of calcium carbonate than prior art increases about 20% to about 50%.The present invention also has an advantage to be, compares with existing system, and the equivalent proportion of its calcium containing compound and sulfur-containing compound is higher, is generally at least 1.3, is preferably about 1.4 or bigger.This system comprises at least one pump 182 and duct coupling 183, is used for delivering to the hydrocyclone from retort Extract slurry with the liquid slurry.
Sulfur oxide vertically is being absorbed in the liquid phase of liquid slurry in the cleaning area 110 in the waste gas, and and the hydroxide ion reaction that is alkalescence generate bisulfites, wherein the part bisulfites can be in cleaning area 110 oxidation and in retort, almost completely be oxidized to sulfate.Alkalescence mainly generates bicarbonate and hydroxide ion from the hydrolysis of calcium carbonate, and it both can also can take place in retort 130 in cleaning area 110.Identical with prior art, preferably adopt a kind of plurality of oxygen injectors to guarantee sufficient reaction, although also can obtain some oxygen in the waste gas from cleaning area 110 itself.In the drop that falls certain reaction taking place also, but mainly is to react in the retort 130 of collecting the liquid slurry.New and an improved feature of the present invention are the holdup time in retort to reduce to about 6 hours from about 15 hours of typical industrial usefulness.In the retort holdup time reduce at the aspects such as quality of handling easy, instrument size and by-produced gypsum some advantages are arranged.
The pH value of liquid slurry should be preferably between about 5.8～about 6.3 between about 5.0～about 6.3 in the retort 130.High pH value representation liquid slurry has stronger effective alkalescence, correspondingly has stronger absorption SO
2Ability.This is an advantage of the present invention, because the calcium carbonate that is provided is fine particle, and also with the recovery that circulates of fine particle form, this point will be introduced in the back, so can obtain higher effective alkalinity.Usually adopt low pH value to increase the reaction speed of calcium carbonate in the Previous System, still, reduce common like this can reducing in cleaning area SO owing to effectively alkaline
2Absorption.Small particle size of the present invention has improved effective alkalescence, even under than the also low situation of desirable pH value, thereby reduced the influence of low pH to a great extent to liquid slurry cleansing power.
What link to each other with injection apparatus array in retort 130 and the vertical cleaning area 110 is a jetting slurry generator, it comprises at least one pump 122 and duct coupling 124, is used for extracting slurries out and transmitting slurries to the injection apparatus array that is arranged in vertical cleaning area from retort 110.
Shown in Fig. 1, lime stone is worn into fine powder in a grinder 170, by a cyclone separator 172 classification, be collected in bag shape chamber 174, and enter compressed air stream in the pipeline 178 through air-lock 176 metering, then it directly sprays into again and cleans in the tower 100 or the next-door neighbour cleans in the flue 20 of tower upstream.On the other hand, can in one jar, mix, be pumped into then in the retort 130 from the lime stone in the bag shape chamber 174.By grinding lime stone in spray site or its contiguous place, the size of comminution of material can strict be controlled.Granular size is very crucial to the present invention.Preferably, about 8 μ of weighted average granular size of the supply of calcium carbonate stream or littler, the particle more than 99% add to replenish because and SO less than 44 μ
xReaction, the calcium carbonate that by-produced gypsum and solvable chloride lost, this point will be introduced in the back.
Air in the pipeline 178 helps to supply with and is used for sulfite oxidation is become the oxygen of sulfate.Retort is preferably stirred with traditional device, and this does not illustrate in the drawings.
The slurries quality that also has that is connected with retort 130 keeps system, by label 180 expressions.For the high respond in the maintenance system, the calcium carbonate that is provided is the particle of being introduced in small, broken bits, and removes part slurries in the retort 130 with hydrocyclone 181, thereby the fine particle of concentrate calcium carbonate comes Recycling and discharges gypsum.Slurries in the hydrocyclone autoreaction jar in 181 future are divided into two strands, and one is to be rich in calcium carbonate and the fine grain circular flow 184 of non-reaction solid; Another strand contains the big relatively calcium sulfate particle of major part.Best, the weighted average diameter of the granularity of calcium carbonate and non-reaction solid is between about 1～about 8 μ, preferably between about 6 μ of about 2-.The weighted average diameter of calcium sulfate particle is between about 25～about 55 μ.Best, the weighted average diameter of calcium sulfate is bigger at least 2 times than calcium carbonate granule, and preferably 5-10 doubly.This system comprises a pump 182 and duct coupling 183 at least, is used for extracting slurries out and transmitting slurries to hydrocyclone from retort.
Circulating line shown in the figure 184, it is connected to hydrocyclone 181 on the retort 130, and sends one circular flow that is rich in calcium carbonate from hydrocyclone.A key character of native system is i.e. blowdown from circular flow 184 from the circulation overflow.What link to each other with circulating line 184 is a discharge conduit 185, and it is applicable to drains a part of circular flow from circulating line.Be preferably on the pipeline 183 or other place provides a slurries chloride content monitor, the slurries amount that control is discharged from pipeline 185, thereby in the reasonable scope with chloride content control in the slurries, as be lower than 30,000mg/l, preferably less than 20,000mg/l, high chloride content can reduce the dissolution velocity of calcium carbonate, has also reduced effective alkalescence of cleaning slurry.Muriatic concentration is the highest in the stream 185, and it is identical with chloride concentration in the retort, so it is the best approach that chloride is eliminated in the system.
Form by relatively little particle with calcium carbonate or the non-reaction solid that is clipped in the system that enters in the air-flow 20 in the retort 130, its weighted average granularity is between 4-12 μ, these non-reaction solids will constantly accumulate in circular flow 184, and its concentration increases in circulating tank 130 thereupon.Can pass through chemical method (analytical characteristics material just, for example, silicon, iron or other) or physical method (just, or using the particle size distribution analysis, overall granule density, or with other suitable method) and monitor the non-reaction solid in the circular flow.A feature of the present invention is to regulate blowdown stream 185 in such a way, promptly controls above-mentioned chloride, the concentration of non-reaction solid in the control retort, or control above-mentioned two aspects simultaneously.The preferential control method that adopts is to regulate the flow velocity of stream 185 on request up or down, satisfies the strictest limit value of chloride or non-reaction solid.Preferably can in retort 130, keep the common weight ratio of content of non-reaction solid to be lower than 20% of total solid, preferably below 15%.
Can handle together with blowdown liquid by the solid that pipeline 185 removes away from retort, from liquid, separate, or handle and make it be suitable for abandoning or make other purposes with other method.Blowdown liquid also can make this stream abandon or do other purposes with handling someway.The present invention never limits the possible processing method of blowdown stream 185, and still, know has many methods can handle it, and it is separated into multiply, whole circulation or part Recycling, or the like.Be used to handle these class methods of stream 185 and install not within category of the present invention.
In addition, also provide calcium sulfate slurry recovery channel 186, it links to each other with hydrocyclone, and removes calcium sulfate from hydrocyclone, and wherein, the particle of calcium sulfate is bigger than calcium carbonate granule.
Fig. 1 has shown the preferential embodiment that adopts of the present invention, and wherein circular flow 184 turns back in the retort 130.According to the present invention, Yun Hang advantage is can increase considerably and contain SO like this
xEffective alkalescence of the drop of waste gas contact.By using directly from the circular flow of hydrocyclone, also can in very short time of contact, handle the waste gas that is rich in sulfur oxide, this circular flow height is rich in very tiny calcium carbonate granule, high pH value and the high calcium and the equivalent proportion of sulphur.
Best, calcium containing compound and sulfur-containing compound, are preferably between about 1.3-about 1.4 between about 1.2-about 2.0 with equivalent proportion in the circular flow 184.The concentration of suspended solid is generally between the 1-10% percentage by weight in the circular flow, and the most common is about 2-about 6%.From lime stone, isolate most of calcium sulfate with hydrocyclone 182,, also reduced the content of solid in the liquid slurry simultaneously except improving above-mentioned equivalent when the effective alkali.
An advantage of used technology combination is that the equivalent proportion of calcium containing compound and sulfur-containing compound is very high in the retort in the treatment process method of the present invention, for example, between the magnitude of about 1.1-about 1.6, is preferably between about 1.2-about 1.3.When the very little advantages of the particle of this advantage and calcium carbonate is got up, just may obtain overall treatment efficiency preferably, simultaneously instrument size and raw material utilize aspect very economicals all.
Preferably from the content of solid in the stream 183 of retort 130 between about 10-about 20%, be preferably between about 13-about 17%.And the content of solid is preferably between about 30-about 55% in the stream 186.Stream 186 is fed in filter 188 or other the suitable device and removes water in the liquid slurry.The quality height of solid gypsum can be used for construction material.Filtrate can be discharged by pipeline 189, and can be recycled in the retort 130 or a part can be used as dirt and discharges, but an advantage of the invention is at native system and there is no need to discharge this stream in order to control the chloride accumulation.
Basically do not have droplets entrained in the waste gas that cleaned, and separated device 140 changes direction.Under the high gas flow speed that the present invention reaches, if do not take measures, will run into the cat head 102 of existing structure and the scale problems of demister, it is infeasible adopting more efficient demister in separator 140, because under the overall operation speed of 4.5～6 meter per seconds, still there is not practical efficient demister, blowdown can to occur bad and overflow for the commercial device of this position particular design, so, increased possibility of jamming and reduced reliability.So separator 140 is to design for specific purposes required for the present invention.
Best, separator 140 is removed the quite most mist of carrying secretly, and the waste gas flow path direction from the vertical axes of tower at least 30 ° of deflections, and be more even velocity fields of one of vertical demister 150 generation.In its preferential form that adopts, diameter can be got rid of by the bigger drop that the downstream demister is removed easily less than major part (by the important computations) drop of 100 μ or by they being dripped from waste gas or allowing them be condensed into.
Being preferably in separator 140 back is vertical demisters, shown in number in the figure 150.The separated device 140 of the bulk velocity of waste gas changes over from vertical direction and approaches horizontal direction.This has some advantages, comprise and reduce drop cleaning the collision of top of tower 102, so that prevent to form deposition, this deposition tends to grow up to a certain degree through certain hour, its meeting bulk is taken off and is split, general diameter has one meter or several meters, is not to damage shower nozzle, can fall into retort 130 exactly and finally cause layer 112 and 112 ' spray nozzle clogging.In addition, importantly, it allows to realize by vertical demister 150 the efficient demist of substantially horizontal air-flow.Blowdown is good in essence for high efficiency levels air-flow demister 150, so allow to move with higher speed than the vertical air-flow demister of similar Design.In addition, it can also obtain the good demist of horizontal gas flow orientation.Although be not unique, demist degree height is a feature of the present invention, because the horizontal gas flow demister is used in the FGD system and other industry that needs efficient demist usually.Yet senior demist is provided is unique feature by a relative even velocity field being provided for demister and finally most of droplets being condensed into before the demist bigger drop in efficient demister in the combination of separator 140 and efficient demister 150.
Fig. 5 has shown the preferred form of improved separator 140, and the vertical current that it could eliminate or condense most of droplet (just, diameter is less than the drop of 100 μ) and direct exhaust effectively departs from the upper wall surface of tower.Separator 140 that shows among Fig. 2 and the horizontal plane structure that cleans tower 100 be γ at an angle.This angle is preferably between about 10 °-Yue 45 °, for example, and about 20 °.
The structure and the orientation of assembly 144 grades all help good blowdown.Each assembly is by illustrated circular array.Assembly 144 grades preferably become the θ angle each other, between about 125～about 145 °, are preferably about 140 ° usually.Cyclone separator arrangement is supported by the member 146 that traverses each length component.Supporting construction also can adopt other design.
The structure of separator 140 allows directly to contact cleaning by fixing 147 pairs of blades of spray gun, fixedly spray gun have can be from top and following jet blower 148 towards blade direct injection rinse water.Clean usually by respectively and have and sequentially operate each cleaning head and finish with other cleaning heads.Rinse water wants quality better and the water yield enough, reduces dissolving salt level saturated on the separator table.The good blowdown that circular array provided of assembly 144 grades and use high-quality rinse water and frequent cleaning combine, and can accomplish essentially no deposition operation.
The separative efficiency that characteristics of the present invention are first separators 140 there is no need and former so high in the used multipass separator in the technology, and this is can use high efficiency, vertical demister 150 because air-flow is changed to horizontal direction from vertical direction.So, although it is desirable low that separative efficiency is cleaned than wet method, but separator only produces very little pressure to fall, for example, less than 0.15 inches of water(in H, the advantage that also has following aspect in addition, spatter property, blowdown, high whole air velocity and air-flow are from the upper wall guiding high-efficiency vertical demister 150 of tower.Demister 150 is the baffling template preferably, as " it " font deflection plate.
Through cleaning and the waste gas of demist just can be discharged in the atmosphere by resembling chimney 160 etc. then.In another preferential embodiment that adopts, waste gas process heating before discharging through demist, as in vertical gas-to-gas heat exchanger, being heated, as what do not examine, the common U.S. Patent application S.N.08/257 that transfers the possession of, 158 (attorney docket 1930-P0020), on July 9th, 1994 is with same inventor's name application.
Improved effect of the present invention is to use following single cycle, wet-cleaning open type spray tower, and its nt wt net weight approximately has only half of present used open type spray tower nt wt net weight.The improved SO that the different and combination of this size is provided by the liquid slurry
xAbsorbability has caused improving about 30% or more total treatment effeciency than existing system.Overall process efficiency is by never removing the SO of unit in the flow of process air
xThe resource value that is spent is measured.These comprise investment and operation cost.
Above introduction be intended to teach those of ordinary skill in the art and how implement the present invention, and do not lie in and introduce various obvious variation of the present invention and modification in detail, these have just come into plain view through the introduction above reading to those of ordinary skill.Yet, must be pointed out that all these tangible modifications and variations are all in by the category of the present invention that following claims limited, claims are intended to cover the key element and the step that can realize the prescription in various settings of described purpose or the order, have in addition in the text specifically except the explanation in contrast to this.
Claims (32)
1, a kind ofly is used for reducing waste gas SO
xThe single cycle of concentration, open type tower, adverse current limestone wet-process cleaning method comprise:
(a) guiding contains SO
xWaste gas stream upwards to flow by a vertical cleaning tower greater than 4.5 meter per second bulk velocities;
(b) in the vertical cleaning area in above-mentioned tower, the water of introducing calcium carbonate in small, broken bits, calcium sulfate and inert solid becomes jetting slurry, makes it contrary waste gas flow path direction by flowing downward in the tower, contacts with waste gas simultaneously;
(c), the liquid slurry is collected in the retort with after waste gas contacts;
(d) Extract slurry from retort;
(e) the liquid slurry of drawing from retort is handled, made it to be divided into two strands, one is a circular flow, and it is rich in the calcium carbonate fine grained; Be rich in calcium sulfate particle in another plume;
(f) in processing procedure, return the circular flow that major part is rich in calcium carbonate granule;
(g) in system, add fresh calcium carbonate as feed, make it be enough to remedy extract out and not Recycling and dissolving and with cleaning area in SO that liquid phase absorbed
xThe calcium of reaction.
2, the weighted average granular size of the calcium carbonate of the method for claim 1, wherein introducing as feed in small, broken bits is less than 8 μ.
3, the method for claim 1, wherein introduce the pH value of liquid slurry in the cleaning tower between about 5.0～about 6.3.
4, the method for claim 1, wherein waste gas stream reaches about 6 meter per seconds through the bulk velocity of cleaning tower.
5, the method for claim 1, wherein comprise an one way separator in the tower, it can reduce the quantity of drop effectively and the direction of air-flow be changed into can use a vertical demister efficiently.
6, method as claimed in claim 5, wherein, tower also comprises a vertical demister, and above-mentioned separator can turn at least 30 ° of angles to the direction of waste gas stream from the vertical axis of tower.
7, the method for claim 1, wherein, the liquid slurry of extracting out from retort is sent in the hydrocyclone, thereby provide one circular flow and one discharge stream, circular flow is rich in the calcium carbonate fine grained, about 6 μ of its weighted average diameter or littler, and the mol ratio of the compound of the compound of this plume calcic and sulfur-bearing is at least 1.3; Discharge stream is rich in bigger calcium sulfite particles, and its weighted average diameter is between about 25～about 55 μ.
8, the method for claim 1, wherein the liquid slurry is extracted out from retort after process was less than 8 hours mean residence time.
9, the method for claim 1, wherein in the circular flow at least a portion liquid slurry be returned in the retort, the mol ratio of the compound of its calcic and the compound of sulfur-bearing is at least 1.3, and solid concentration is less than 10%.
10, method as claimed in claim 9, wherein, the mol ratio of the compound of the compound of calcic and sulfur-bearing is greater than about 1.4 in the circular flow.
11, method as claimed in claim 9, wherein, circular flow comprises at least 5% suspended solid.
12, the method for claim 1, wherein liquid slurry is introduced by nozzle, and these nozzles are lined up two-layer, and the spacing between two-layer is less than 2 meters, and the adjacent nozzles jet direction replaces up and down mutually.
13, the method for claim 1, wherein, fine powder calcium carbonate weighted average granular size in the retort is maintained at about between 2～about 6 μ, and the weighted average granular size of the calcium carbonate in small, broken bits of introducing is less than about 8 μ, calculates by weight 99% particle less than 44 μ.
14, the method for claim 1, wherein in the retort pH value of liquid slurry between about 5.8～about 6.3.
15, a kind ofly be used for reducing waste gas SO
xThe single cycle of concentration, open type tower, adverse current limestone wet-process cleaning method, it comprises:
(a) guiding contains SO
xWaste gas upwards to flow by a vertical cleaning tower to the bulk velocity of about 6 meter per seconds greater than 4.5 meter per seconds;
(b) the vertical cleaning area in above-mentioned tower, the water of introducing calcium carbonate in small, broken bits, calcium sulfate and inert solid becomes jetting slurry, and its contrary waste gas flow path direction is flowed downward by tower, contacts with waste gas simultaneously;
(c) with after waste gas contacts, the liquid slurry is collected in the retort;
(d) after less than about 8 hours mean residence time, Extract slurry from retort;
(e) liquid extracted out from retort slurry is handled and formed two strands, one is a circular flow, is rich in the calcium carbonate fine grained, and another thigh is rich in calcium sulfate particle;
(f) circular flow that major part is rich in calcium carbonate turns back in the processing procedure; And
(g) in system, introduce fresh calcium carbonate as feed, make it be enough to remedy extract out and not Recycling and dissolving and with cleaning area in SO that liquid phase absorbed
xThe calcium of reaction, the weighted average granular size of the calcium carbonate granule of introducing as feed in small, broken bits when introducing less than about 10 μ.
16, method as claimed in claim 15, wherein, the pH value of introducing the liquid slurry that cleans in the tower is between about 5.0～about 6.3.
17, method as claimed in claim 16, wherein, the pH value of liquid slurry is maintained at about between 5.8～about 6.3 in the retort.
18, method as claimed in claim 15, wherein, tower also comprises an one way separator, it can reduce the quantity of droplet effectively, and the direction of waste gas stream changed over can utilize a vertical demister efficiently.
19, method as claimed in claim 18, wherein, tower also comprises a vertical demister, and above-mentioned separator can turn at least 30 ° of angles to the waste gas flow path direction from the vertical axes of tower.
20, method as claimed in claim 15, wherein, the liquid slurry of extracting out from retort is sent in the hydrocyclone, and form one circular flow and one discharge stream, circular flow is rich in the calcium carbonate fine grained, about 8 μ of its weighted average diameter or littler, and the mol ratio of the compound of its calcic and the sulphur compound that contains is at least 1.3; Discharge stream is rich in bigger calcium sulfite particles, and its weighted average diameter is between about 25～about 55 μ.
21, method as claimed in claim 20, wherein, the liquid slurry at least a portion in the circular flow is sent back in the retort, and the mol ratio of the compound of its calcic and the sulphur compound that contains is at least 1.3.
22, method as claimed in claim 21, wherein, the mol ratio of the compound of the compound of calcic and sulfur-bearing and comprises in the circular flow and is less than 5% suspended solid greater than about 1.4 in the circular flow.
23, method as claimed in claim 15, wherein, calcium carbonate will grind before in be provided to liquid slurry as feed, to keep 99% calcium carbonate granule less than 44 μ, the weighted average size of calcium carbonate granule is between about 6 μ of about 2-in the retort, the weighted average granular size of the calcium carbonate of introducing as feed in small, broken bits is less than about 8 μ, calculates by weight 99% particle less than 44 μ.
24, a kind ofly be used for reducing waste gas SO
xThe single cycle of concentration, open type tower, adverse current limestone wet-process cleaning method, it comprises:
(a) guiding contains SO
xWaste gas stream vertically clean tower by one and upwards flow;
(b) in the vertical cleaning area in above-mentioned tower, introduce the water pulping liquid droplets of calcium carbonate in small, broken bits, calcium sulfate and inert solid, best, the weighted average diameter of calcium carbonate is about 6 μ or littler, and the mol ratio of the compound of calcic and the compound of sulfur-bearing is at least 1.1, the direction of the contrary waste gas stream of these slurries contacts with waste gas stream simultaneously by flowing downward in the tower;
(c) with after waste gas contacts, the liquid slurry is collected in the retort, the pH value of slurries is maintained at about between 5.0～about 6.3;
(d) when in retort after less than 6 hours mean residence time, Extract slurry from retort;
(e) in hydrocyclone the liquid slurry of extracting out from retort is handled, and formed two strands, one is a circular flow, and it is rich in the calcium carbonate fine grained, and its weighted average granular size is less than 6 μ; Another strand is rich in calcium sulfate particle, and its weighted average diameter is between about 25～about 55 μ;
(f) mol ratio that will be rich in the compound of the compound of calcium carbonate and calcic and the sulfur-bearing part that is at least 1.4 circular flow turns back in the processing procedure;
(g) in system, introduce fresh calcium carbonate as feed, make it to be enough to remedy extract out and not Recycling and dissolving and with the SO that is absorbed in the cleaning area liquid phase
xThe calcium of reaction, the weighted average granular size of above-mentioned calcium carbonate in small, broken bits when introducing less than about 8 μ.
25, method as claimed in claim 24, wherein, tower also comprises an one way separator, it can be changed into the direction of air-flow can use a vertical demister efficiently.
26, method as claimed in claim 24, wherein, liquid slurry is introduced vertical cleaning area by nozzle, and these nozzles are lined up two-layer, and the spacing between two-layer is less than 2 meters, and the flow direction of two adjacent nozzles is interlaced up and down.
27, method as claimed in claim 24, wherein, calcium carbonate will grind before adding the liquid slurry as feed, the calcium carbonate granule of maintenance 99% is less than 44 μ, the weighted average size of calcium carbonate is maintained at about between 2～about 6 μ in the retort, the weighted average granular size of the calcium carbonate in small, broken bits that adds as feed is less than about 8 μ, calculates by weight 99% particle less than 44 μ.
28, a kind ofly be used for reducing waste gas SO
xThe single cycle of concentration, open type tower, adverse current limestone wet-process cleaning method, it comprises:
(a) guiding contains SO
xWaste gas stream vertically clean tower with whole flow velocity by one and upwards flow greater than 4.5 meter per seconds;
(b) in the vertical cleaning area in above-mentioned tower, introduce the water pulping liquid droplets of calcium carbonate in small, broken bits, calcium sulfate and inert solid, it is contacted with waste gas and flow downward by the contrary waste gas flow path direction of tower, above-mentioned liquid slurry is introduced by jet blower, these jet blowers are divided into two-layer, two interlamellar spacings are less than about 2 meters, and the flow direction of adjacent nozzle is staggered up and down;
(c), the liquid slurry is collected in the retort with after waste gas contacts;
(d) Extract slurry from retort;
(e) liquid of discharging from retort slurry is handled and formed two strands, one is a circular flow, and it is rich in calcium carbonate granule; And another plume is rich in calcium sulfate particle;
(f) circular flow that at least a portion is rich in calcium carbonate turns back to processing procedure;
(g) introduce fresh calcium carbonate as feed in system, its quantity extracts and not Recycling and dissolving and the SO that absorbed with the cleaning area liquid phase to remedy
xThe calcium of reaction.
29, a kind ofly reduce SO in the waste gas by wet-cleaning
xThe method of concentration, it comprises:
(a) guiding contains SO
xWaste gas stream clean tower by one and upwards flow;
(b) water of introducing calcium carbonate in small, broken bits, calcium sulfate and calcium sulfite and non-reaction solid becomes jetting slurry, makes it to pass the contrary waste gas of tower and flows to current downflow, and the weighted average size of calcium carbonate is between about 1～about 8 μ;
(c), the liquid slurry is collected in the retort with after waste gas contacts;
(d) Extract slurry and the liquid slurry of extracting out delivered to handle in the hydrocyclone and form two plumes from retort, one is a circular flow, it is rich in the calcium carbonate fine grained, another strand liquid is rich in calcium sulfate, all comprise the chloride of dissolving in two strands of liquid streams, and will discharge, thereby remove the chloride or the non-reaction solid of dissolving as the calcium sulfate of solid and the part of circular flow, perhaps the both is removed, and keeps the high respond of slurries with said method; And
(e) introduce fresh calcium carbonate as feed in system, its quantity is enough to remedy because the calcium that the discharge of the separation of above-mentioned calcium sulfate and above-mentioned a certain proportion of circular flow consumes, during the weighted average granular size introducing of above-mentioned calcium carbonate in small, broken bits less than about 10 μ.
30, a kind ofly reduce SO in the burnt gas
xThe method of concentration, it comprises:
(a) provide a cleaning tower, it comprises a gas feed flue, a gas vent flue and a vertical cleaning area, is configured to upwards to flow by above-mentioned vertical cleaning area by steering current;
(b) mix an injection apparatus array in above-mentioned cleaning area, above-mentioned array is used to introduce calcium carbonate in small, broken bits, calcium sulfate, calcium sulfite and the water of non-reaction solid and becomes jetting slurry, makes it contrary airflow direction and flows downward by tower;
(c) supply with the calcium carbonate of weighted average granular size as feed less than 8 μ;
(d) provide a retort below above-mentioned injection apparatus array, it can collect the liquid slurry in above-mentioned vertical cleaning area with after waste gas contacts a period of time, and described retort has suitable size, to allow SO
xWith calcium carbonate reaction, and form calcium sulphate crystal, at least 2 times of the weighted average particle diameters of this calcium sulphate crystal are to the particle diameter of the calcium carbonate that adds as feed;
(e) Extract slurry from retort is delivered to the injection apparatus array that is arranged in above-mentioned cleaning area with the liquid slurry; And
(f) Extract slurry from above-mentioned retort, the liquid extracted out in retort slurry delivered in the hydrocyclone and form two plumes, one is a circular flow, it is rich in the calcium carbonate fine grained, be rich in bigger calcium sulfate in another plume, determine muriatic content in the circular flow, discharge a part of circular flow, keep the low chloride content of liquid slurry in the retort with this according to fixed chloride content.
31, a kind ofly reduce SO in the waste gas by wet-cleaning
xThe method of concentration, it comprises:
(a) guiding contains SO
xWaste gas stream clean tower by one and upwards flow;
(b) introduce calcium carbonate in small, broken bits, calcium sulfate, calcium sulfite and the water of non-reaction solid and become jetting slurry, make it contrary waste gas flow path direction and land downwards by tower, the pH value of liquid slurry is between about 5.0～about 6.3 in the retort;
(c) the liquid slurry is collected in the retort;
(d) Extract slurry from above-mentioned retort, the liquid that to extract out from retort slurry is delivered in the hydrocyclone and is formed two plumes, one is a circular flow, it is rich in the calcium carbonate fine grained, another plume is rich in bigger calcium sulfate particle, determine chloride content in the circular flow, discharge a part of circular flow, keep the low chloride content of liquid slurry in the retort with this according to this chloride content.
(e) return part circulation and flow in the retort, the mol ratio of the compound of this stream calcic and the compound of sulfur-bearing is greater than 1.3;
(f) from hydrocyclone, extract the stream that is rich in calcium sulfate out and reclaim calcium sulfate; And
(g) introduce fresh calcium carbonate in system, its quantity is enough to remedy the calcium of discharge, and the weighted average granular size of above-mentioned calcium carbonate in small, broken bits is less than about 10 μ.
32, a kind ofly be used for reducing waste gas SO
xThe wet-cleaning device of concentration, it comprises:
(a) cleaning tower, it comprises a gas access flue; A gas vent flue and a vertical cleaning area are configured to and can direct exhaust upwards flow by above-mentioned cleaning area;
(b) injection apparatus array, it is positioned at above-mentioned cleaning area, becomes the contrary airflow direction of jetting slurry to land by tower downwards in order to the water that guides calcium carbonate in small, broken bits;
(c) retort, it is positioned at below the above-mentioned injection apparatus array, and with it can collect the liquid slurry after gas contacted a period of time, the size of above-mentioned retort is suitable for allowing calcium carbonate and SO in above-mentioned vertical cleaning area
2Reaction and form gypsum crystal, the weighted average particle diameter of this gypsum crystal liken at least 2 times greatly of the calcium carbonate granules that add into feed to;
(d) provide the device of calcium carbonate, the weighted average granular size that joins the calcium carbonate in the above-mentioned retort as feed is less than about 10 μ;
(e) jetting slurry generator, it comprises at least one pump and duct coupling, is used for starching and deliver to the injection apparatus array that is arranged in above-mentioned cleaning area from the retort Extract;
(f) a liquid slurry quality keeps system, and it comprises, a hydrocyclone, and this hydrocyclone can be divided into two plumes to the above-mentioned liquid slurry in the retort, and one is rich in the calcium carbonate granule, and another strand is rich in the calcium sulfate of larger particles; At least one pump and duct coupling are used for starching and delivering to the hydrocyclone from the retort Extract; A circulating line, it connects above-mentioned hydrocyclone and above-mentioned retort and send the circular flow that one is rich in calcium carbonate from above-mentioned hydrocyclone; A discharge tube, it links to each other with above-mentioned circulating line, is suitable for discharging from above-mentioned circulating line a part of circular flow; With a calcium sulfate liquid slurry recovery approach, it is connected with above-mentioned hydrocyclone and discharges calcium sulfate liquid and starch from above-mentioned hydrocyclone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95194199 CN1153482A (en) | 1994-06-09 | 1995-06-07 | Improved wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/257,698 | 1994-06-09 | ||
| US08/257,160 | 1994-06-09 | ||
| CN 95194199 CN1153482A (en) | 1994-06-09 | 1995-06-07 | Improved wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1153482A true CN1153482A (en) | 1997-07-02 |
Family
ID=5082616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95194199 Pending CN1153482A (en) | 1994-06-09 | 1995-06-07 | Improved wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents |
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| Country | Link |
|---|---|
| CN (1) | CN1153482A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101641553B (en) * | 2007-03-13 | 2012-02-15 | 阿尔斯托姆科技有限公司 | Improved direct sorbent preparation/feed apparatus and method for circulating fluidized bed boiler systems |
| CN102395417A (en) * | 2009-02-06 | 2012-03-28 | R·J·安维科 | System, apparatus and method for carbon dioxide sequestration |
| CN105289169A (en) * | 2012-08-21 | 2016-02-03 | 美铝公司 | Systems for removing particulate matter from a gas stream |
| CN106139873A (en) * | 2016-08-22 | 2016-11-23 | 哈尔滨蔚蓝环保设备制造有限公司 | A kind of desulfurization by lime gypsum method device |
| CN106731618A (en) * | 2017-02-14 | 2017-05-31 | 哈尔滨蔚蓝环保设备制造有限公司 | Boiler SNCR urea method denitrating systems |
| CN106745153A (en) * | 2016-09-23 | 2017-05-31 | 封祁宁 | denitration gypsum cleaning device and method |
-
1995
- 1995-06-07 CN CN 95194199 patent/CN1153482A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101641553B (en) * | 2007-03-13 | 2012-02-15 | 阿尔斯托姆科技有限公司 | Improved direct sorbent preparation/feed apparatus and method for circulating fluidized bed boiler systems |
| CN102395417A (en) * | 2009-02-06 | 2012-03-28 | R·J·安维科 | System, apparatus and method for carbon dioxide sequestration |
| CN105289169A (en) * | 2012-08-21 | 2016-02-03 | 美铝公司 | Systems for removing particulate matter from a gas stream |
| CN106139873A (en) * | 2016-08-22 | 2016-11-23 | 哈尔滨蔚蓝环保设备制造有限公司 | A kind of desulfurization by lime gypsum method device |
| CN106745153A (en) * | 2016-09-23 | 2017-05-31 | 封祁宁 | denitration gypsum cleaning device and method |
| CN106731618A (en) * | 2017-02-14 | 2017-05-31 | 哈尔滨蔚蓝环保设备制造有限公司 | Boiler SNCR urea method denitrating systems |
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