CN102172472A - Method for smoke desulphurization by utilizing dolomitic lime - Google Patents
Method for smoke desulphurization by utilizing dolomitic lime Download PDFInfo
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- CN102172472A CN102172472A CN2011100393312A CN201110039331A CN102172472A CN 102172472 A CN102172472 A CN 102172472A CN 2011100393312 A CN2011100393312 A CN 2011100393312A CN 201110039331 A CN201110039331 A CN 201110039331A CN 102172472 A CN102172472 A CN 102172472A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
The invention relates to a method for smoke desulphurization by utilizing dolomitic lime. Dolomitic lime is hydrolyzed and digested into lime cream; the lime cream reacts with a MgCl2 solution, so that Ca(OH)2 is converted into CaCl2 to enter a liquid phase, but Mg(OH)2 enters a solid phase, thus calcium-magnesium separation is realized; partial Mg(OH)2 filter cakes are blended and pulped to be sent into an adsorption unit to covert SO2 and SO3 into MgSO4 so as to achieve the purpose of desulphurization; the residual parts of Mg(OH)2 filter cakes are dried to obtain Mg(OH)2 or calcined to obtain MgO; a MgSO4 solution obtained by desulphurization reacts with a CaCl2 solution obtained by calcium-magnesium separation, thereby forming a CaSO4.2H2O precipitate and the MgCl2 solution so as to obtain CaSO4.1/2H2O building gypsum; and the MgCl2 solution and the dolomitic lime cream are subjected to calcium-magnesium separation. The method has the advantages of abundant and cheap raw material and quick process; and a byproduct has higher use value and market prospect, and zero emission of solid and waste water can be realized.
Description
Technical field
The present invention relates to a kind of flue gas desulfurization technique, especially a kind of is raw material with the calcined dolomite in powder, removes in the flue gas particularly SO in the coal-fired flue-gas
2Process.
Background technology
Sulfur dioxide is to cause one of air-polluting main matter, and is very big to environment, ecology, economic development and human health damage.China has classified sulfur dioxide as a kind of main regulatory control air pollutants, and with the concentration level of sulfur dioxide in the atmosphere as an important indicator estimating air quality, form the high pressure situation of rigid management and examination.
For obtaining the desulfur technology that is fit to national conditions, country is from " the Seventh Five-Year Plan ", a series of corresponding brainstorm subjects have been arranged, a series of improvement technology have been researched and developed, since " eight or five ", begin from external introduction improvement technology, built large quantities of power plant, steel mill and industrial boiler desulfurizing test, demonstrative project in China, but still can't practical requirement.
At present, generally approve both at home and abroad and what take is lime method and two kinds of main sulfur removal technology principles of magnesium oxide/hydroxide method.
Lime method sweetening process basic principle is with the SO in the lime slurry absorption flue gas
2, generate calcium sulfite, be calcium sulfate with calcium sulfite oxidation then.Its sulfur removal technology principle and characteristics are:
Ca(OH)
2+SO
2→CaSO
3·1/2H
2O
2CaSO
3·1/2H
2O+O
2+H
2O→2CaSO
4·2H
2O
Magnesium oxide/hydroxide is to absorb SO in the flue gas with the slurry that magnesium oxide/hydroxide is made as the sweetening process of desulfurizing agent
2Generate magnesium sulfite, entering the air oxidation magnesium sulfite is the bigger magnesium sulfate of solubility.Its sulfur removal technology principle and characteristics are:
SO
2+H
2O→H
2SO
3
MgSO
3+H
2SO
3→Mg(HSO
3)
2
Mg(HSO
3)
2+Mg(OH)
2→2MgSO
3+2H
2O
MgSO
3+2O
2→MgSO
4
The characteristics that the characteristics of lime method desulfurization are desulfuration efficiency height, technology maturation, the absorbent price is low, but there is the problem that floor space is big, construction investment is many, main problem is that this process pipe, nozzle and desulfurizing tower encrustation are serious, cause the tower internal volume to diminish, desulfuration efficiency reduces.And the reaction main feature of magnesium oxide/hydroxide desulfurization is that the reactive desulfurizing agent activity is big, the desulfuration efficiency height, the comprehensive method of investment is low, the advantage that operating cost is little, but, also there is the subject matter of two aspects: the one, the product magnesium sulfate after the desulfurization is the material that a kind of solubility is very big, use value is very low, though can not produce fouling and obstruction in equipment, can directly discharge after the doctor solution dehydration and enter the sea, but for numerous interior ground enterprises, be worthless; The 2nd, what raw materials of magnesium oxide adopted mostly is magnesite, and this resource reserves are fewer and feweri and price is more and more higher, also form obstacle for being extensive use of this technology.
Summary of the invention
Purpose of the present invention just provides a kind of lime method, two kinds of sulfur removal technologies of magnesium oxide/hydroxide method of combining, sufficient raw, cheap, fast, the accessory substance of reaction has higher use value and market prospects, solids and waste water realize that the calcined dolomite in powder of zero-emission standard is used for the method for flue gas desulfurization.
The technology that the inventive method is taked may further comprise the steps:
1. digest purification step: it is the calcined dolomite in powder breast that the calcined dolomite in powder hydrolytic digestion is also made with extra care;
2. calcium magnesium separating step: described calcined dolomite in powder breast adds the MgCl of capacity
2Solution reacts, the CaCl of generation
2Enter liquid phase, Mg (OH)
2Enter solid phase;
3. SO
2, SO
3Remove step: with 2. gained Mg (OH) of step
2Reconcile into slurry, be transported to SO in absorptive unit and the flue gas
2, SO
3, O
2Desulfurization is carried out in reaction, makes SO
2And SO
3Transform and form MgSO
4The aqueous solution;
4. the dry decomposition step of gypsum deposition: with 3. gained MgSO of step
4Solution and step be the CaCl of the capacity of gained 2.
2Liquid reacts, and forms CaSO
42H
2O precipitation and MgCl
2Solution, sediment is through sedimentation or filtration washing and obtain CaSO dry the decomposition
41/2H
2The O plaster of Paris, MgCl
2Solution is sent into step and is 2. recycled;
5. drying and dehydrating and calcining and decomposing step: with 2. gained Mg (OH) of step
2Dry evaporation makes Mg (OH)
2Finished product, perhaps calcining and decomposing makes the MgO finished product.
The inventive method is at first also made with extra care the calcined dolomite in powder hydrolytic digestion and is the calcined dolomite in powder breast; MgCl with capacity
2Solution carries out calcium magnesium separating reaction, makes the Ca (OH) in calcined dolomite in powder Ruzhong
2Be transformed into the high CaCl of solubility
2Liquid enters liquid phase, makes the Mg (OH) in calcined dolomite in powder Ruzhong
2Enter solid phase, washing has realized that calcium magnesium separates after filtration; With the isolated Mg of a part (OH)
2The filter cake dilution reconciles into slurry, is transported to absorptive unit flue gas is carried out desulfurization, makes SO
2And SO
3Transform and form MgSO
4The aqueous solution reaches the desulfurization purpose; With the isolated Mg of another part (OH)
2The filtration cakes torrefaction transpiring moisture makes high activity Mg (OH)
2Finished product, perhaps calcining and decomposing obtains highly active chemical grade MgO finished product; MgSO with desulfurization formation
4The CaCl of solution and the capacity that obtains during calcium magnesium separates
2Liquid carries out the gypsum deposition reaction, forms CaSO
42H
2O precipitation and MgCl
2Solution, after sedimentation or filtration washing separation, sediment or the decomposition of filter cake drying obtain CaSO
41/2H
2O plaster of Paris, and MgCl
2Solution and calcined dolomite in powder breast carry out calcium magnesium separating reaction again, make the present invention repeat to realize.
Use the MgCl of capacity
2Solution carries out calcium magnesium separating reaction, can promote CaO thoroughly to be converted into the high CaCl of solubility
2Solution realizes that calcium magnesium separates, and also can prevent Ca (OH) as far as possible
2Enter the SO in desulfurization process and the flue gas
2And SO
3Reaction generates insoluble calcium sulfite and calcium sulfate, avoids blocking pipe, absorption tower nozzle and fouling, has also prevented to influence byproduct CaSO to greatest extent
41/2H
2O plaster of Paris and Mg (OH)
2Quality.
Use the CaCl of capacity
2Liquid carries out the gypsum deposition reaction, is in order to promote MgSO
4Thoroughly be converted into sediment CaSO
42H
2The O precipitation prevents that as far as possible the sulfate ion in the liquid from following MgCl
2The Ca (OH) in solution returns calcium magnesium when separating and calcined dolomite in powder Ruzhong
2Reaction generates CaSO
42H
2The O precipitation enters Mg (OH)
2Filter cake and influence Mg (OH)
2The quality of filter cake.
The MgCl that uses in the process
2And CaCl
2And MgSO
4Solution all is the product that generates in the system, and also being needs the product that consumes in the respective process, and the molecular amounts of its generation is suitable with the molecular amounts of consumption.Owing to generate MgCl in the process
2Solution, so, except initial period adds a certain amount of MgCl
2Outside the solution, in practical operation, need only the MgCl that replenishes small loss
2Solution can satisfy MgCl
2The needs of solution.
Wash Mg (OH) in the process
2The washing lotion of filter cake contains CaCl
2Liquid component, this washing lotion or and CaCl
2The liquid merging is used in MgSO
4Aqueous solution precipitation reaction perhaps is used for the hydrolytic digestion of calcined dolomite in powder and obtains utilization as the prescription water.When being used for the hydrolytic digestion of calcined dolomite in powder as the prescription water, CaCl
2Itself do not participate in reaction, and be enriched to newly-generated CaCl at ensuing calcium magnesium separating step
2In the solution.
Wash CaSO in the process
42H
2O filter cake or sedimentary washing lotion contain MgCl
2Solution composition, this washing lotion or and MgCl
2Solution merges the calcium magnesium separating reaction that is used in the calcined dolomite in powder breast, perhaps is used for the hydrolytic digestion of calcined dolomite in powder and obtains utilization as the prescription water, can also be used for Mg (OH) as the prescription water
2The filter cake dilution reconciles into slurry.
The MgCl that generates in the system
2Solution can directly be used for the hydrolytic digestion of calcined dolomite in powder as the prescription water, moisture in the minimizing system makes the MgCl in the system
2Obtain enrichment, reduced calcium magnesium separating step MgCl
2The addition of solution improves MgCl
2The concentration of solution; The MgCl that generates in the system
2Solution also can directly be used for Mg (OH) as the prescription water
2The filter cake dilution reconciles into slurry, and moisture in the minimizing system makes the MgCl in the system
2Obtain enrichment, reduced calcium magnesium separating step MgCl
2The addition of solution improves MgCl
2The concentration of solution.In the actual implementation process, newly-generated MgCl in the system
2The concentration of solution has tangible reduction, can pass through newly-generated MgCl
2Solution or be used for the hydrolytic digestion of calcined dolomite in powder, perhaps MgCl as the prescription water
2Solution directly is used for Mg (OH) as the prescription water
2The filter cake dilution reconciles into slurry, perhaps utilizes the mode of fume afterheat evaporation to reduce MgCl
2The moisture of solution keeps MgCl
2The concentration level of solution.MgCl
2Solution is used for the hydrolytic digestion of calcined dolomite in powder as the prescription water, the calcium magnesium separating reaction that part shifts to an earlier date can occur, and this helps enforcement direction of the present invention and matching process principle.MgCl
2Solution directly is used for Mg (OH) as the prescription water consumption
2The filter cake dilution reconciles into slurry, MgCl in sweetening process
2Do not participate in reacting and in system, retaining, and generating new MgCl
2The time obtain enrichment, and keep MgCl
2Solution concentration and first filling MgCl
2Solution concentration is suitable.In like manner, contain MgCl
2The cleaning solution of composition also can utilize in this way.
CaSO
42H
2O filter cake or sediment also can obtain containing a small amount of MgCl without the direct drying decomposition of washing
2The CaSO of composition
41/2H
2The O plaster of Paris.
Comprise that slurry enters the water of system, part is evaporated in flue gas desulfurization, and part is evaporated in filtration cakes torrefaction, calcining; Calcined dolomite in powder that drops into and the MgCl that replenishes
2Solution finally has been made into Mg (OH)
2Perhaps MgO finished product and CaSO
41/2H
2The O plaster of Paris has been realized the zero-emission of sweetening process discarded object and waste water.
The chemical principle of foundation of the present invention is:
Hydrolytic digestion MgOCaO+2H
2O → Mg (OH)
2Ca (OH)
2
Calcium magnesium separates Mg (OH)
2Ca (OH)
2+ MgCl
2→ 2Mg (OH)
2↓+CaCl
2
SO
2Remove Mg (OH)
2+ SO
2+ O
2→ MgSO
4+ H
2O
SO
3Remove Mg (OH)
2+ SO
3→ MgSO
4+ H
2O
Gypsum deposition MgSO
4+ CaCl
2+ 2H
2O → CaSO
42H
2O ↓+MgCl
2
The dry CaSO that decomposes
42H
2O → CaSO
41/2H
2O+3/2H
2O
Drying and dehydrating Mg (OH)
2H
2O → Mg (OH)
2+ H
2O
Calcining and decomposing Mg (OH)
2→ MgO+H
2O
The preferred processing step of the present invention is:
1. digest purification step: with calcined dolomite in powder and water according to 1: 3-8 weight ratio batching, reinforced while stirring in digestive shelf, be the calcined dolomite in powder breast with the calcined dolomite in powder hydrolytic digestion.This is the step that is easy to realize, and is lower to conditional requests such as calcined dolomite in powder activity, reaction temperatures, certainly, uses the active high calcined dolomite in powder of hot water and employing more to help reaction and carries out.Then the calcined dolomite in powder breast is separated with spinning liquid by sieving and make with extra care, remove the sand grains and the dolomite in dedust Ruzhong and give birth to impurity such as piece, obtain the refining calcined dolomite in powder breast of solids content 10-20%;
2. calcium magnesium separating step: the MgCl that will make with extra care calcined dolomite in powder breast and the concentration 5-20% of capacity
2Solution carries out calcium magnesium to be separated, and makes the Mg (OH) in calcined dolomite in powder Ruzhong
2Sediment keeps solid phase, and Ca (OH)
2Then reaction forms CaCl
2Liquid enters liquid phase, through filtration washing the two is separated and obtains Mg (OH) respectively
2Filter cake and CaCl
2Solution; Wash Mg (OH) in this process
2The washing lotion of filter cake contains CaCl
2Liquid component, this washing lotion or and CaCl
2The liquid merging is used in MgSO
4Aqueous solution precipitation reaction perhaps is used for the hydrolytic digestion of calcined dolomite in powder as the prescription water.
3. SO
2, SO
3Remove step: with Mg (OH)
2Filter cake and water are according to 1: the dilution of 2-8 weight ratio reconciles into slurry, is transported to SO in absorptive unit and the flue gas
2And SO
3And the O in the flue gas
2Desulfurization is carried out in reaction, makes SO
2And SO
3Transform the MgSO that forms high-dissolvability
4Solution; With MgSO
4The Mg (OH) that the part that solution and desulfuration absorbing tower bottom are compiled does not react completely
2Sediment separates by separation means such as sedimentation separation, isolated by filtration, and supernatant that obtains or filtrate are MgSO
4Solution is transported to down step gypsum deposition process, the unreacted Mg (OH) that obtains
2Slurry or filter cake return this step and reconcile into slip for reusing;
4. the dry decomposition step of gypsum deposition: with the MgSO that forms after the desulfurization
4The CaCl of the capacity that solution and calcium magnesium separating step obtain
2Solution carries out the precipitation reaction of dihydrate gypsum, forms CaSO
42H
2O precipitation and MgCl
2The supernatant of solution; CaSO
42H
2Behind process washing of O precipitation or the filtration washing, filter cake obtains CaSO through 150-250 ℃ of drying and crushing again
41/2H
2The O plaster of Paris.This step cleaning solution or with newly-generated MgCl
2Solution turns back to calcium magnesium separating step and uses, and perhaps turns back to calcined dolomite in powder hydrolytic digestion step as the prescription water, perhaps directly is used for Mg (OH) as the prescription water
2The filter cake dilution reconciles into slurry, perhaps utilizes the mode of fume afterheat evaporation to reduce MgCl
2The moisture of solution keeps MgCl
2The concentration level of solution.Newly-generated MgCl
2When solution concentration is low, can pass through newly-generated MgCl
2Solution or be used for the hydrolytic digestion of calcined dolomite in powder, perhaps MgCl as the prescription water
2Solution directly is used for Mg (OH) as the prescription water
2The filter cake dilution reconciles into slurry, perhaps utilizes the mode of fume afterheat evaporation to reduce MgCl
2The moisture of solution keeps MgCl
2The concentration level of solution.
5. drying and dehydrating and calcining and decomposing step: the Mg (OH) that calcium magnesium separating step is obtained through washing
2Filter cake carries out drying and crushing at 400-600 ℃ and obtains having highly active Mg (OH)
2Finished product obtains highly active chemical grade MgO finished product with this filter cake through 800-1000 ℃ of calcining.
The series of chemical that the invention process process is related, under common flue gas treatment conditions, be swift in response thoroughly, less demanding to temperature, concentration, pressure condition, can be applied in a flexible way according to concrete fume indication and raw material supply condition in the practice, whole process mass transport is smooth and easy, easy to operate is advisable to satisfy.Principle of the invention process can also effectively remove in the flue gas harmful substances such as solid grit except can realizing the desulfurization purpose, realize the zero-emission of discarded object and waste water.Implement when of the present invention, flue gas can pass through dust removal process earlier, and this can help more guaranteeing that the quality of byproduct satisfies certain quality and requires and improved the economic benefit of smoke gas treatment.
The present invention has following remarkable advantage:
Compare with lime method desulfurization, magnesium oxide/hydroxide sulfur removal technology, the present invention has overcome product blocking pipe after the lime method desulfurization, nozzle and scale problems, also overcome the restriction of magnesium oxide/hydroxide desulfurization principle and technology product magnesium sulfate conditions of discharge, and combine the advantage of lime method, two kinds of sulfur removal technologies of magnesium oxide/hydroxide method, with two kinds of technology combinations, not only by cheap MgCl
2The ingenious calcined dolomite in powder calcium magnesium separation problem that solved of solution, also feasible calcined dolomite in powder that drops into and the MgCl that replenishes
2Solution finally has been made into Mg (OH)
2Perhaps MgO finished product and CaSO
41/2H
2The O plaster of Paris, greatly reduced desulphurization cost, truly solving sweetening process discarded object and wastewater zero discharge requirement, the advantage that also has abundant, the cheap and technological principle science of raw material sources, supporting enforcement is convenient, simple to operate and invests aspect such as little provides strong technical support for realizing energy-saving and emission-reduction, environmental improvement task object.
The specific embodiment
Now be described in further detail with regard to the present invention by embodiment.
1. the inventive method comprises the steps: that containing 5% sand grains and dolomite with 100 kilograms gives birth to the calcined dolomite in powder of impurity such as piece to stir digestion while feed in raw material according to 1: 6 weight ratio with water in digestive shelf be the calcined dolomite in powder breast, makes MgOCaO and water generation Mg (OH)
2Ca (OH)
2Aqueous mixtures.Remove the sand grains and the dolomite in grey Ruzhong by screen and give birth to impurity such as piece, 695 kilograms of the ash breasts after obtaining making with extra care, wherein, refining grey Ruzhong Mg (OH)
2Ca (OH)
2Growing amount be 130.63 kilograms, solids content percentage is 18.8%.
2. with 1. 695 kilograms of calcined dolomite in powder breasts of gained of step, add 940.1 kilogram 10% MgCl
2Solution promptly makes the Mg (OH) of generation in calcined dolomite in powder Ruzhong
2Sediment keeps solid phase, and Ca (OH)
2Then reaction forms CaCl
2Liquid enters liquid phase, obtains moisture about 70% Mg (OH) respectively through filtering, wash to separate
2382.67 kilograms of filter cakes and 8.12% CaCl
21352.43 kilograms of solution, wherein CaCl
2Comprise 100 kilograms of slurries in the solution.
Step 2. in, adopt the MgCl of capacity
2Can promote CaO thoroughly to be converted into the high CaCl of solubility
2Solution realizes that calcium magnesium separates, and also can prevent Ca (OH) as far as possible
2Enter the SO in desulfurization process and the flue gas
2And SO
3Reaction generates insoluble calcium sulfite and calcium sulfate, avoids blocking pipe, absorption tower nozzle and fouling, has also prevented to influence byproduct CaSO to greatest extent
41/2H
2O plaster of Paris and Mg (OH)
2Quality.
3. with 2. moisture about 70% the Mg of gained (OH) of step
2Promptly 191.34 kilograms of half of filter cake reconcile into 956.7 kilograms of slurries according to 1: 4 weight ratio water, are transported to SO in absorptive unit and the flue gas
2, SO
3, O
2Desulfurization is carried out in reaction, makes SO
2And SO
3Transform the MgSO that forms high-dissolvability
4Solution, in this step, Mg (OH)
2191.34 kilograms of 20% moisture in the slurry are evaporated by high-temperature flue gas and discharge, and form 765.36 kilograms of concentration and be 15.52% MgSO
4Solution is with MgSO
4The Mg (OH) that the part that solution and desulfuration absorbing tower bottom are compiled does not react completely
2Sediment is by sedimentation separation, and the supernatant that obtains is MgSO
4Solution is transported to next step gypsum deposition process, the unreacted Mg (OH) that obtains
2Slurry returns this step, and reconciles into the slip repeated use.
4. the dry decomposition step of gypsum deposition: 765.36 kilograms of concentration that 3. step is formed after the desulfurization are 15.52% MgSO
4Solution is with 2. 8.12% CaCl of the capacity that obtains of calcium magnesium separating step of step
21352.43 kilograms of precipitation reaction of carrying out dihydrate gypsum of solution form moisture 30% CaSO
42H
2The MgCl of 240.34 kilograms of O precipitations and 1877.45 kilogram 5%
2Solution after sediment separated through twice washing of 100 kg of water, turns back to the calcined dolomite in powder digestion step with cleaning solution as the prescription water, will precipitate CaSO completely
42H
2O obtains 143.5 kilograms of CaSO through 200 ℃ of drying and crushing
41/2H
2The O plaster of Paris.
Step 4. in, adopt the CaCl of capacity
2Be in order to promote MgSO
4Thoroughly be converted into sediment CaSO
42H
2O prevents that as far as possible the sulfate ion in the liquid from following MgCl
2The Ca (OH) in solution returns calcium magnesium when separating and calcined dolomite in powder Ruzhong
2Reaction generates CaSO
42H
2The O precipitation enters Mg (OH)
2Filter cake and influence Mg (OH)
2The quality of filter cake.
5. drying and dehydrating and calcining and decomposing step: moisture about 71% the Mg (OH) that 2. step is obtained through washing
2Promptly 191.34 kilograms of second half of filter cake carry out drying and crushing at 500 ℃ and obtain having highly active Mg (OH)
257.4 kilograms of finished products obtain 39.59 kilograms of highly active chemical grade MgO finished products with this filter cake through 900 ℃ of calcinings.In this step, Mg (OH)
2Filter cake contains 70% the moisture of having an appointment and is evaporated in dry run.
Claims (2)
1. a calcined dolomite in powder is used for the method for flue gas desulfurization, it is characterized in that, may further comprise the steps:
1. digest purification step: it is the calcined dolomite in powder breast that the calcined dolomite in powder hydrolytic digestion is also made with extra care;
2. calcium magnesium separating step: described calcined dolomite in powder breast adds the MgCl of capacity
2Solution reacts, the CaCl of generation
2Enter liquid phase, Mg (OH)
2Enter solid phase;
3. SO
2, SO
3Remove step: with 2. gained Mg (OH) of step
2Reconcile into slurry, be transported to SO in absorptive unit and the flue gas
2, SO
3, O
2Desulfurization is carried out in reaction, makes SO
2And SO
3Transform and form MgSO
4The aqueous solution;
4. the dry decomposition step of gypsum deposition: with 3. gained MgSO of step
4Solution and step be the CaCl of the capacity of gained 2.
2Liquid reacts, and forms CaSO
42H
2O precipitation and MgCl
2Solution, sediment is through sedimentation or filtration washing and obtain CaSO dry the decomposition
41/2H
2The O plaster of Paris, MgCl
2Solution is sent into step and is 2. recycled;
5. drying and dehydrating and calcining and decomposing step: with 2. gained Mg (OH) of step
2Dry evaporation makes Mg (OH)
2Finished product, perhaps calcining and decomposing makes the MgO finished product.
2. calcined dolomite in powder according to claim 1 is used for the method for flue gas desulfurization, it is characterized in that, may further comprise the steps:
1. digest purification step: with calcined dolomite in powder and water according to 1: 3-8 weight ratio batching, in digestive shelf, stir while feed in raw material, be the calcined dolomite in powder breast with calcined dolomite in powder digestion; The calcined dolomite in powder breast separated with spinning liquid by sieving make with extra care, remove the impurity such as sand grains rock ballast in the milk of lime, obtain the refining calcined dolomite in powder breast of solids content 10-20%;
2. calcium magnesium separating step: with the MgCl of described refining calcined dolomite in powder breast with the concentration 5-20% of capacity
2Solution carries out calcium magnesium to be separated, and makes the Mg (OH) in calcined dolomite in powder Ruzhong
2Sediment keeps solid phase, the CaCl of formation
2Liquid enters liquid phase, through filtration washing the two is separated and obtains Mg (OH) respectively
2Filter cake and CaCl
2Solution; Wash Mg (OH) in this process
2The washing lotion of filter cake contains CaCl
2Liquid component, this washing lotion or and CaCl
2The liquid merging is used in MgSO
4Aqueous solution precipitation reaction perhaps is used for the hydrolytic digestion of calcined dolomite in powder as the prescription water;
3. SO
2, SO
3Remove step: with Mg (OH)
2Filter cake and water are according to 1: the dilution of 2-8 weight ratio reconciles into slurry, is transported to SO in absorptive unit and the flue gas
2, SO
3, O
2Desulfurization is carried out in reaction, makes SO
2, SO
3Change into MgSO
4Solution; With MgSO
4The Mg (OH) that the part that solution and desulfuration absorbing tower bottom are compiled does not react completely
2Sediment separates by sedimentation, filtration etc., and supernatant that obtains or filtrate are MgSO
4Solution, the unreacted Mg (OH) that obtains
2Slurry or filter cake return this step and reconcile into slip for recycling;
4. the dry decomposition step of gypsum deposition: the MgSO that 3. step is formed
4The CaCl of the capacity that 2. solution and step obtain
2Solution carries out the precipitation reaction of dihydrate gypsum, forms CaSO
42H
2O precipitation and MgCl
2The supernatant of solution; CaSO
42H
2Behind process washing of O precipitation or the filtration washing, filter cake obtains CaSO through 150-250 ℃ of drying and crushing again
41/2H
2The O plaster of Paris; This step cleaning solution or with newly-generated MgCl
2Solution turns back to step and 2. carries out the separation of calcium magnesium, perhaps turns back to step as the prescription water and 1. carries out calcined dolomite in powder digestion, and perhaps directly conduct is filled a prescription water for Mg (OH)
2The filter cake dilution reconciles into slurry, perhaps utilizes the mode of fume afterheat evaporation to reduce MgCl
2The moisture of solution keeps MgCl
2The concentration level of solution;
5. drying and dehydrating and calcining and decomposing step: the Mg (OH) that 2. step is obtained through washing
2Filter cake carries out drying and crushing at 400-600 ℃ and obtains having highly active Mg (OH)
2Finished product obtains highly active chemical grade MgO finished product with this filter cake through 800-1000 ℃ of calcining.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100393312A CN102172472B (en) | 2011-02-14 | 2011-02-14 | Method for smoke desulphurization by utilizing dolomitic lime |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100393312A CN102172472B (en) | 2011-02-14 | 2011-02-14 | Method for smoke desulphurization by utilizing dolomitic lime |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102172472A true CN102172472A (en) | 2011-09-07 |
| CN102172472B CN102172472B (en) | 2013-05-08 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102502724A (en) * | 2011-11-02 | 2012-06-20 | 中国科学院青海盐湖研究所 | Method for preparing magnesia for magnesium cement by using bischofite and dolomite |
| CN103566726A (en) * | 2013-11-05 | 2014-02-12 | 彭振超 | Method for preparing magnesium hydroxide, magnesium oxide and gypsum from dolomite lime denitration and desulfurization of flue gas |
| CN103922369A (en) * | 2014-03-22 | 2014-07-16 | 彭振超 | Process of producing magnesium carbonate-series products by dolomite lime smoke gas desulfurization carbon-drop power generation |
| CN103950957A (en) * | 2014-04-22 | 2014-07-30 | 彭振超 | Process method for preparing magnesium hydroxide from magnesium sulfate |
| CN107032384A (en) * | 2017-06-05 | 2017-08-11 | 中南大学 | A kind of method that calcium and magnesium is separated and recovered from Calcium magnesium minerals |
| CN108067095A (en) * | 2018-02-28 | 2018-05-25 | 沈阳化工大学 | A kind of method that dry-desulphurizer, gypsum, magnesium sulfate and magnesium hydroxide are prepared using dolomite |
| CN111701436A (en) * | 2020-06-23 | 2020-09-25 | 湖北真诚纸业有限公司 | Novel dual-alkali desulfurization method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1143535A (en) * | 1995-08-22 | 1997-02-26 | 东洋工程株式会社 | Exhaust gas desulfurization process |
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2011
- 2011-02-14 CN CN2011100393312A patent/CN102172472B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1143535A (en) * | 1995-08-22 | 1997-02-26 | 东洋工程株式会社 | Exhaust gas desulfurization process |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102502724A (en) * | 2011-11-02 | 2012-06-20 | 中国科学院青海盐湖研究所 | Method for preparing magnesia for magnesium cement by using bischofite and dolomite |
| CN103566726A (en) * | 2013-11-05 | 2014-02-12 | 彭振超 | Method for preparing magnesium hydroxide, magnesium oxide and gypsum from dolomite lime denitration and desulfurization of flue gas |
| CN103566726B (en) * | 2013-11-05 | 2016-02-03 | 彭振超 | Calcined dolomite in powder denitrating flue gas desulfurization preparing magnesium hydroxide, magnesia and gypsum method |
| CN103922369A (en) * | 2014-03-22 | 2014-07-16 | 彭振超 | Process of producing magnesium carbonate-series products by dolomite lime smoke gas desulfurization carbon-drop power generation |
| CN103950957A (en) * | 2014-04-22 | 2014-07-30 | 彭振超 | Process method for preparing magnesium hydroxide from magnesium sulfate |
| CN107032384A (en) * | 2017-06-05 | 2017-08-11 | 中南大学 | A kind of method that calcium and magnesium is separated and recovered from Calcium magnesium minerals |
| CN107032384B (en) * | 2017-06-05 | 2019-02-22 | 中南大学 | A method of separating and recovering calcium and magnesium from Calcium magnesium minerals |
| CN108067095A (en) * | 2018-02-28 | 2018-05-25 | 沈阳化工大学 | A kind of method that dry-desulphurizer, gypsum, magnesium sulfate and magnesium hydroxide are prepared using dolomite |
| CN111701436A (en) * | 2020-06-23 | 2020-09-25 | 湖北真诚纸业有限公司 | Novel dual-alkali desulfurization method |
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