CN111187016A - System and process for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum and product thereof - Google Patents
System and process for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum and product thereof Download PDFInfo
- Publication number
- CN111187016A CN111187016A CN202010043588.4A CN202010043588A CN111187016A CN 111187016 A CN111187016 A CN 111187016A CN 202010043588 A CN202010043588 A CN 202010043588A CN 111187016 A CN111187016 A CN 111187016A
- Authority
- CN
- China
- Prior art keywords
- gypsum
- strength
- filtrate
- reaction
- semi
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000010440 gypsum Substances 0.000 title claims abstract description 77
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 76
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 63
- 239000000706 filtrate Substances 0.000 claims abstract description 48
- 238000006243 chemical reaction Methods 0.000 claims abstract description 40
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims abstract description 38
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 34
- 230000023556 desulfurization Effects 0.000 claims abstract description 34
- 239000002002 slurry Substances 0.000 claims abstract description 25
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000003546 flue gas Substances 0.000 claims abstract description 24
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000011575 calcium Substances 0.000 claims abstract description 22
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 22
- 239000012066 reaction slurry Substances 0.000 claims abstract description 21
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000011010 flushing procedure Methods 0.000 claims abstract description 18
- 238000001035 drying Methods 0.000 claims abstract description 16
- 230000008569 process Effects 0.000 claims abstract description 13
- 239000012043 crude product Substances 0.000 claims abstract description 12
- 239000000047 product Substances 0.000 claims abstract description 9
- 239000007788 liquid Substances 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 238000000926 separation method Methods 0.000 claims abstract description 6
- 238000005406 washing Methods 0.000 claims description 37
- 238000003860 storage Methods 0.000 claims description 18
- 239000007789 gas Substances 0.000 claims description 17
- 239000012266 salt solution Substances 0.000 claims description 17
- 239000001110 calcium chloride Substances 0.000 claims description 13
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 12
- 239000007787 solid Substances 0.000 claims description 10
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 7
- 150000004683 dihydrates Chemical class 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 239000003245 coal Substances 0.000 claims 1
- 238000004064 recycling Methods 0.000 abstract description 5
- 150000003839 salts Chemical class 0.000 description 6
- 239000002912 waste gas Substances 0.000 description 5
- 239000000428 dust Substances 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 229910001424 calcium ion Inorganic materials 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- KIUKXJAPPMFGSW-DNGZLQJQSA-N (2S,3S,4S,5R,6R)-6-[(2S,3R,4R,5S,6R)-3-Acetamido-2-[(2S,3S,4R,5R,6R)-6-[(2R,3R,4R,5S,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-2-carboxy-4,5-dihydroxyoxan-3-yl]oxy-5-hydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-3,4,5-trihydroxyoxane-2-carboxylic acid Chemical compound CC(=O)N[C@H]1[C@H](O)O[C@H](CO)[C@@H](O)[C@@H]1O[C@H]1[C@H](O)[C@@H](O)[C@H](O[C@H]2[C@@H]([C@@H](O[C@H]3[C@@H]([C@@H](O)[C@H](O)[C@H](O3)C(O)=O)O)[C@H](O)[C@@H](CO)O2)NC(C)=O)[C@@H](C(O)=O)O1 KIUKXJAPPMFGSW-DNGZLQJQSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920002674 hyaluronan Polymers 0.000 description 1
- 229960003160 hyaluronic acid Drugs 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 238000011165 process development Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229920001285 xanthan gum Polymers 0.000 description 1
- 239000000230 xanthan gum Substances 0.000 description 1
- 229940082509 xanthan gum Drugs 0.000 description 1
- 235000010493 xanthan gum Nutrition 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
- C04B11/262—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke waste gypsum other than phosphogypsum
- C04B11/264—Gypsum from the desulfurisation of flue gases
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Treating Waste Gases (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a system, a process and a product for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum, wherein the process comprises the steps of mixing underflow slurry of a cyclone of a calcium-based wet flue gas desulfurization system and a calcium chloride solution in a reaction kettle for reaction, carrying out solid-liquid separation and two-stage flushing on the reaction slurry through a vacuum belt conveyor after the reaction is finished to obtain a α -semi-hydrated gypsum crude product, a reaction slurry filtrate, a first-stage flushing water filtrate and a second-stage flushing water filtrate, drying the α -semi-hydrated gypsum crude product to obtain the high-strength α -semi-hydrated gypsum, recycling the reaction slurry filtrate and the first-stage flushing water filtrate for preparing the calcium chloride solution, and recycling the second-stage flushing water filtrate for preparing the calcium chloride solution.
Description
Technical Field
The invention relates to the technical field of industrial waste recycling, in particular to a system and a process for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum and a product thereof.
Background
In recent ten years, the calcium-based wet flue gas desulfurization process has become domesticThe largest flue gas desulfurization process, thereby producing a large amount of desulfurization byproducts, mainly desulfurization gypsum. If the desulfurized gypsum is not properly disposed and comprehensively utilized, the desulfurized gypsum is bound to become solid waste, possibly causes secondary pollution to the environment, and can restrict the development of the calcium-based wet flue gas desulfurization process. Therefore, SO can be fundamentally solved only by realizing effective resource utilization of the desulfurized gypsum2The method has the advantages of increasing the selection space of the flue gas desulfurization method, improving the technical level of wet flue gas desulfurization, expanding the environmental capacity of process development, realizing the conversion from 'resource-product-waste discharge and tail end treatment' to 'resource-product-renewable resource and recycling' mode, and promoting the credit-worthwhile circulation of the desulfurization industry.
The patent specification with the publication number of CN 107572571A discloses a preparation method of high-strength sheet α -semi-hydrated gypsum, which comprises the steps of mixing desulfurized gypsum, water, sulfate (potassium sulfate or aluminum sulfate) and a biomacromolecule polysaccharide crystal transformation agent (hyaluronic acid or xanthan gum), stirring and refluxing for 2-4 hours in a reactor under the conditions of normal pressure, 93-97 ℃ and pH value of 4.5-7.5, and finally dehydrating, washing and drying to obtain α -semi-hydrated gypsum.
The patent specification with the publication number of CN 107399755A discloses a method for preparing high-whiteness short-column α -hemihydrate gypsum from desulfurized gypsum, which comprises the steps of mixing concentrated hydrochloric acid, water, calcium chloride and desulfurized gypsum, heating to 95-100 ℃ for reaction, aging after the reaction is finished, filtering, washing to be neutral, drying, mixing with water, NaCl and succinic acid, adjusting the pH value of slurry to 7-12, placing the slurry in a crystallization kettle for reaction, filtering, and drying to obtain the high-whiteness short-column α -hemihydrate gypsum.
The patent specification with the publication number of CN 100345788C discloses a preparation method of α type high-strength gypsum, 0.1-1% of a medium crystal agent and 10-15% of water are mixed into desulfurized gypsum and uniformly stirred, the mixture is mechanically pressed into a sphere or a block, the sphere or the block is placed into an autoclave to be autoclaved at the temperature of 135-160 ℃ for 1-3 hours under the saturated steam condition, the temperature is kept at 80-100 ℃, and finally the dried and crushed product is α type high-strength gypsum.
Disclosure of Invention
Aiming at the defects in the field, the invention provides a process for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum, which takes underflow slurry of a cyclone of a coal-fired flue gas calcium-based wet desulphurization system as a raw material and prepares the high-strength α -semi-hydrated gypsum by a normal-pressure salt solution method, and the subsequent operation process of the whole process does not need to supplement salt solution and generates no new secondary pollutants, so that the investment and operation cost is low, the problem of difficult treatment of desulfurized gypsum can be solved, and the final product, namely the high-strength α -semi-hydrated gypsum, also has extremely high application value.
Mixing and reacting rotational flow underflow slurry of a calcium-based wet flue gas desulfurization system and calcium chloride solution in a reaction kettle, carrying out solid-liquid separation and two-stage flushing on the reaction slurry through a vacuum belt conveyor after the reaction is finished to obtain α -semi-hydrated gypsum crude product, reaction slurry filtrate, first-stage flushing water filtrate and second-stage flushing water filtrate, and drying α -semi-hydrated gypsum crude product to obtain the high-strength α -semi-hydrated gypsum;
and recovering the reaction slurry filtrate and the first-stage washing water filtrate to prepare the calcium chloride solution, and recovering the second-stage washing water filtrate to use the calcium-based wet flue gas desulfurization system.
The conventional technology is to prepare α -semi-hydrated gypsum by taking dehydrated desulfurized gypsum as a raw material, and the invention changes the production process of coal-fired flue gas calcium-based wet desulfurized gypsum, cyclone underflow slurry does not directly enter a vacuum belt conveyor, but enters a reaction kettle first, and generates α -semi-hydrated gypsum crude product under the action of calcium chloride solution and then enters the vacuum belt conveyor, so that the dehydration and washing processes can be saved, the investment and operation cost can be reduced, the water balance of the whole system can be ensured, and no new wastewater is generated.
The coal-fired flue gas usually contains chlorine-containing gas such as HCl and the like, and is absorbed by the desulfurization slurry after calcium-based wet flue gas desulfurization, and the main components of the desulfurization slurry are calcium sulfate dihydrate and calcium carbonate, so that the cyclone underflow slurry often contains a large amount of chloride ions and calcium ions, and the calcium chloride carried away by the α -hemihydrate gypsum and the second-stage flushing water can be supplemented by the chloride ions and the calcium ions in the cyclone underflow slurry, so that the concentration balance of the salt solution of the whole system is realized, new calcium chloride does not need to be supplemented, and the operation cost can be reduced.
Preferably, the solid content of the cyclone underflow slurry is 40-60%, and the purity of the dihydrate gypsum in the solid matter is more than 85%.
In order to prevent the calcium chloride solution from crystallizing out, the temperature of the calcium chloride solution is preferably 25-40 ℃, and the mass fraction of the calcium chloride is preferably 40-50%.
Preferably, the volume ratio of the cyclone underflow slurry to the calcium chloride solution is 1: 0.8-3.
Preferably, the reaction temperature is 90-98 ℃, and the reaction time is 2-5 h.
Preferably, in the two-stage washing, the volume ratio of the first-stage washing water to the reaction slurry is 1: 6-40, and the volume ratio of the second-stage washing water to the reaction slurry is 1: 0.5-1.5. The secondary washing water filtrate is recycled and used for the calcium-based wet flue gas desulfurization system, and can be used for specifically using as water for slurrying, washing of a demister of a desulfurization tower and the like, so that on one hand, not only is the water required for slurrying and washing of the demister of the desulfurization tower originally saved, but also the water balance of the whole system can be ensured, no new waste water is generated, on the other hand, the secondary washing water filtrate finally enters the cyclone to become a part of the cyclone underflow slurry, circulation is formed, and the cost is reduced.
Preferably, the α -hemihydrate gypsum crude product has an attached water content of 5% to 30%.
Preferably, the drying temperature is 100-150 ℃, and when the drying temperature is too high, α -hemihydrate gypsum is dehydrated to form anhydrous gypsum.
The invention also provides high-strength α -semi-hydrated gypsum prepared by the process, wherein the high-strength α -semi-hydrated gypsum has the attached water content of less than 3 percent, the whiteness of more than 70 and the flexural strength of more than 25 MPa.
The invention also provides a system for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum, which comprises a coal-fired boiler and a calcium-based wet flue gas desulfurization system, wherein the calcium-based wet flue gas desulfurization system comprises a cyclone, and the system further comprises:
the saline solution storage tank is provided with a first temperature control device and is used for preparing and storing the calcium chloride solution;
the top of the reaction kettle is communicated with the cyclone underflow pipe and the salt solution storage tank, and the bottom of the reaction kettle is provided with a discharge port;
a material inlet is communicated with the discharge port, a first section of washing water spray head and a second section of washing water spray head are sequentially arranged above a belt of the vacuum belt along the material advancing direction, a front section of filtrate collecting tank and a rear section of filtrate collecting tank are arranged at the bottom of the vacuum belt, the front section of filtrate collecting tank is communicated with the saline solution storage tank and is used for recovering the reaction slurry filtrate and the first section of washing water filtrate, and the rear section of filtrate collecting tank is connected with the calcium-based wet flue gas desulfurization system and is used for recovering the second section of washing water filtrate;
and the dryer is used for drying the α -semi-hydrated gypsum coarse product, the top of the dryer is provided with a gas outlet and a feed inlet communicated with the material outlet of the vacuum belt conveyor, and the bottom of the dryer is provided with a discharge hole and a gas inlet for high-temperature drying gas to enter.
Preferably, the gas outlet is in communication with a main flue of the coal-fired boiler. The waste gas of the dryer enters a main flue of the coal-fired boiler through a gas outlet, and is discharged after being treated by purification equipment (such as a dust remover and the like).
Compared with the prior art, the invention has the main advantages that:
1. the normal-pressure salt solution method is adopted as a reaction mode, so that the investment is low, the energy consumption is low, high-pressure equipment is not required, and the method is safe and stable.
2. The invention can be seamlessly butted with the existing coal-fired flue gas calcium-based wet desulphurization, and continuous production operation is realized.
3. The high-strength α -hemihydrate gypsum is prepared by using the underflow slurry of the cyclone as a raw material, so that one dewatering and washing process can be saved, the investment and operation cost can be reduced, and the water balance of the whole system can be ensured.
4. By recycling the filtrate and utilizing chloride ions and calcium ions in the cyclone underflow slurry to supplement calcium chloride carried away by α -hemihydrate gypsum and secondary washing water, the balance of the salt solution concentration of the whole system is realized, new calcium chloride does not need to be supplemented, and the operation cost is reduced.
5. The waste gas at the outlet of the dryer is directly introduced into the flue of the main boiler body, so that subsequent waste gas purification equipment can be omitted, and the investment and the operation cost are saved.
Drawings
FIG. 1 is a schematic diagram of a system for producing high strength α -hemihydrate from desulfurized gypsum of an example;
in the figure, a desulfurization system 1, a cyclone 2, a salt solution storage tank 3, a salt bin 4, a reaction kettle 5, a vacuum belt conveyor 6, reaction slurry filtrate and first-stage flushing water filtrate 7, second-stage flushing water filtrate 8, a dryer 9, high-temperature drying gas 10, a main flue 11, α -a semi-hydrated gypsum bin 12.
Detailed Description
The invention is further described with reference to the following drawings and specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are conducted under conditions not specified, usually according to conventional conditions, or according to conditions recommended by the manufacturer.
As shown in fig. 1, the system for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum of the embodiment comprises a coal-fired boiler and a corresponding calcium-based wet flue gas desulfurization system (desulfurization system for short) 1, wherein the coal-fired boiler is provided with a main flue 11, and the calcium-based wet flue gas desulfurization system 1 comprises a cyclone 2, and the system further comprises a salt solution storage tank 3, a salt bin 4, a reaction kettle 5, a vacuum belt conveyor 6, a dryer 9, α -semi-hydrated gypsum bin 12.
Salt storehouse 4 is used for storing and supplying with calcium chloride, and the bottom is equipped with the electric control valve who takes metering function, the feed rate of steerable calcium chloride, and 4 bottom calcium chloride exports in salt storehouse are located 3 tops of salt solution storage tank, and pass through the tube coupling with 3 tops of salt solution storage tank. The salt bin 4 conveys calcium chloride to the salt solution storage tank 3 when the first reaction and the system operation are abnormal, and the concentration of the calcium chloride in the salt solution storage tank 3 is ensured to be within a reasonable range.
The salt solution storage tank 3 is used for preparing and storing calcium chloride solution, is provided with a first temperature control device and is used for controlling the temperature of the calcium chloride solution in the tank. The saline solution storage tank 3 is connected with the top of the reaction kettle 5 through a pipeline.
The cyclone 2 receives the slurry from the desulfurization system 1, and the underflow outlet is positioned above the reaction kettle 5 and is connected with the top of the reaction kettle 5 through a pipeline.
The reaction kettle 5 is used as a reaction vessel for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum, is provided with a second temperature control device and is used for controlling the reaction temperature, a stirring device is also arranged in the reaction kettle 5, the bottom of the reaction kettle 5 is connected with a discharge pump, and the other end of the discharge pump is connected with a material inlet of the vacuum belt conveyor 6.
A first section of washing water spray head and a second section of washing water spray head are sequentially arranged above the belt of the vacuum belt conveyor 6 along the advancing direction of the material. The bottom of the vacuum belt conveyor 6 is provided with a front filtrate collecting tank and a rear filtrate collecting tank, the front filtrate collecting tank is connected with the saline solution storage tank 3 through a pipeline and is mainly used for recovering reaction slurry filtrate and a section of washing water filtrate 7; the rear section filtrate collecting tank is connected with the desulfurization system 1 through a pipeline and is mainly used for recovering the filtrate 8 of the second-section washing water. The material outlet of the vacuum belt conveyor 6 is connected with the material inlet at the top of the dryer 9.
The dryer 9 is used for drying α -semi-hydrated gypsum crude products, the bottom of the dryer is provided with a discharge hole connected with the α -semi-hydrated gypsum bin 12, the gas in the dryer 9 flows from bottom to top, a gas inlet at the bottom is connected with a pipeline of high-temperature dry gas 10, a gas outlet at the top is connected with a boiler main flue 11 in front of a dust remover and other purification equipment, and waste gas discharged from a gas outlet of the dryer 9 enters the main flue 11 of the coal-fired boiler and is discharged after being treated by the purification equipment (such as the dust remover and the like).
The system of the embodiment is adopted to prepare high-strength α -hemihydrate gypsum from desulfurized gypsum, and the process flow is as follows:
slurry of the desulfurization system 1 is conveyed to the cyclone 2 through a pipeline, and after cyclone layering, underflow slurry with the solid content of 40-60% (the purity of dihydrate gypsum in solid matter is more than 85%) enters a reaction kettle 5 through a pipeline; the salt bin 4 conveys calcium chloride to the salt solution storage tank 3, and the mass fraction of the calcium chloride solution in the tank is kept to be 40-50%; the temperature of the salt solution storage tank 3 is controlled to be 25-40 ℃, and the flow rate is controlled by an electric valve, so that the volume ratio of the calcium chloride solution entering the reaction kettle 5 to the underflow slurry of the cyclone 2 is controlled to be 0.8-3: 1; after the underflow slurry of the cyclone 2 and the calcium chloride solution enter the reaction kettle 5, the mixture is stirred and mixed uniformly by a stirring device arranged in the reaction kettle 5.
The reaction temperature of the reaction kettle 5 is controlled to be 90-98 ℃, and the reaction residence time is controlled to be 2-5 hours. After the reaction is finished, the obtained reaction slurry is conveyed to a vacuum belt conveyor 6 through a pipeline for solid-liquid separation.
α -semi-hydrated gypsum subjected to solid-liquid separation is washed in two sections through a washing water spray head arranged above a vacuum belt conveyor 6, the volume ratio of the first section of washing water to the reaction slurry is 1: 6-40, the volume ratio of the second section of washing water to the reaction slurry is 1: 0.5-1.5, reaction slurry filtrate obtained by solid-liquid separation and first section of washing water filtrate 7 are collected and then conveyed back to a salt solution storage tank 3 to serve as a calcium chloride solution for standby, and second section of washing water filtrate 8 is collected and then conveyed back to a desulfurization system 1 to serve as water for dissolving and washing a demister of a desulfurization tower.
The content of the adhering water of the washed α -semi-hydrated gypsum at the outlet of the vacuum belt conveyor 6 is 5% -30%, the cleaned α -semi-hydrated gypsum is conveyed to a dryer 9 through a belt, the temperature of the dryer 9 is controlled at 100-150 ℃, a heat source is provided by high-temperature drying gas 10, the dried high-strength α -semi-hydrated gypsum enters a α -semi-hydrated gypsum bin 12, the obtained high-strength α -semi-hydrated gypsum finished product has the adhering water content of less than 3%, the whiteness is greater than 70, the flexural strength is greater than 25MPa, and the dried waste gas enters a boiler main body flue 11 in front of a dust remover and is discharged after being purified.
Application example 1
The calcium-based wet desulphurization system of a 35t/h coal-fired boiler in a self-contained power plant adopts the process and the system for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum of the embodiment, and the flow rate of the slurry of the cyclone sub-underflow is 1.05m3The solid content is 50 percent, the purity of the dihydrate gypsum in the solid matter is 92 percent, the attached water content of the high-strength α -hemihydrate gypsum finished product is 2.3 percent, the whiteness is 70, and the flexural strength is 26 MPa.
The temperature of the reaction kettle is controlled at 96 ℃, the retention time is controlled at 4 hours, the mass fraction of the calcium chloride solution is 45 percent, and the flow rate of the calcium chloride solution is 2.05m3Per h, first stage flushing water flow of 0.30m3The flow rate of the second-stage flushing water is 2.90m3The α -hemihydrate gypsum crude product at the material outlet of the vacuum belt conveyor had an attached water content of 14%.
Application example 2
The calcium-based wet desulphurization system of a 75t/h coal-fired boiler in a self-contained power plant adopts the process and the system for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum of the embodiment, and the flow rate of the slurry of the cyclone sub-underflow is 2.03m3The solid content is 50 percent, the purity of the dihydrate gypsum in the solid matter is 90.5 percent, the attached water content of the high-strength α -hemihydrate gypsum finished product is 2.5 percent, the whiteness is 75 percent, and the flexural strength is 25 MPa.
The temperature of the reaction kettle is controlled at 97 ℃, the retention time is controlled at 3.5 hours, the mass fraction of the calcium chloride solution is 50 percent, and the flow rate of the calcium chloride solution is 3.95m3Per h, first stage flushing water flow rate of 0.58m3H, the flow rate of the second-stage flushing water is 6.00m3The α -hemihydrate gypsum crude product from the material outlet of the vacuum belt conveyor had an attached water content of 16%.
Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the above description of the present invention, and equivalents also fall within the scope of the invention as defined by the appended claims.
Claims (10)
1. Mixing and reacting cyclone underflow slurry of a calcium-based wet flue gas desulfurization system and a calcium chloride solution in a reaction kettle, carrying out solid-liquid separation and two-stage flushing on the reaction slurry through a vacuum belt conveyor after the reaction is finished to obtain α -semi-hydrated gypsum crude product, reaction slurry filtrate, first-stage flushing water filtrate and second-stage flushing water filtrate, and drying α -semi-hydrated gypsum crude product to obtain the high-strength α -semi-hydrated gypsum;
and recovering the reaction slurry filtrate and the first-stage washing water filtrate to prepare the calcium chloride solution, and recovering the second-stage washing water filtrate to use the calcium-based wet flue gas desulfurization system.
2. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1, wherein the solids content of said underflow slurry of cyclone is 40-60%, and the purity of dihydrate gypsum in the solid matter is greater than 85%;
the temperature of the calcium chloride solution is 25-40 ℃, and the mass fraction of calcium chloride is 40-50%.
3. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1 or 2, wherein the volume ratio of the cyclone underflow slurry to the calcium chloride solution is 1: 0.8-3.
4. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1, wherein the reaction temperature is 90-98 ℃ and the reaction time is 2-5 h.
5. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1, wherein the volume ratio of the first-stage washing water to the reaction slurry in the two-stage washing is 1: 6-40, and the volume ratio of the second-stage washing water to the reaction slurry is 1: 0.5-1.5.
6. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1, wherein the adsorbed water content of said α -hemihydrate gypsum crude product is 5% to 30%.
7. The process for preparing high-strength α -hemihydrate gypsum from desulfurized gypsum according to claim 1, wherein the drying temperature is 100-150 ℃.
8. The high-strength α -hemihydrate gypsum prepared by the process as claimed in any one of claims 1 to 7, wherein the high-strength α -hemihydrate gypsum has an attached water content of less than 3%, a whiteness of more than 70, and a flexural strength of more than 25 MPa.
9. A system for preparing high-strength α -semi-hydrated gypsum from desulfurized gypsum, which comprises a coal-fired boiler and a calcium-based wet flue gas desulfurization system, wherein the calcium-based wet flue gas desulfurization system comprises a cyclone, and is characterized in that the process of any one of claims 1 to 7 is adopted, and the system further comprises:
the saline solution storage tank is provided with a first temperature control device and is used for preparing and storing the calcium chloride solution;
the top of the reaction kettle is communicated with the cyclone underflow pipe and the salt solution storage tank, and the bottom of the reaction kettle is provided with a discharge port;
a material inlet is communicated with the discharge port, a first section of washing water spray head and a second section of washing water spray head are sequentially arranged above a belt of the vacuum belt along the material advancing direction, a front section of filtrate collecting tank and a rear section of filtrate collecting tank are arranged at the bottom of the vacuum belt, the front section of filtrate collecting tank is communicated with the saline solution storage tank and is used for recovering the reaction slurry filtrate and the first section of washing water filtrate, and the rear section of filtrate collecting tank is connected with the calcium-based wet flue gas desulfurization system and is used for recovering the second section of washing water filtrate;
and the dryer is used for drying the α -semi-hydrated gypsum coarse product, the top of the dryer is provided with a gas outlet and a feed inlet communicated with the material outlet of the vacuum belt conveyor, and the bottom of the dryer is provided with a discharge hole and a gas inlet for high-temperature drying gas to enter.
10. The system of claim 9, wherein the gas outlet is in communication with a main flue of the coal fired boiler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010043588.4A CN111187016B (en) | 2020-01-15 | 2020-01-15 | System and process for preparing high-strength alpha-semi-hydrated gypsum from desulfurized gypsum and product thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010043588.4A CN111187016B (en) | 2020-01-15 | 2020-01-15 | System and process for preparing high-strength alpha-semi-hydrated gypsum from desulfurized gypsum and product thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111187016A true CN111187016A (en) | 2020-05-22 |
| CN111187016B CN111187016B (en) | 2022-04-29 |
Family
ID=70704388
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010043588.4A Active CN111187016B (en) | 2020-01-15 | 2020-01-15 | System and process for preparing high-strength alpha-semi-hydrated gypsum from desulfurized gypsum and product thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111187016B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1513766A (en) * | 2003-06-06 | 2004-07-21 | 浙江大学 | Techlogogy for making alpha semi-water desulfur gypsum using normal pressure salt solution method |
| CN2813074Y (en) * | 2005-08-16 | 2006-09-06 | 孙克勤 | Gypsum slurry dewatering device in wet-process flue gas desulfurizing system |
| CN101182150A (en) * | 2007-11-09 | 2008-05-21 | 浙江大学 | Industrial crystallization technique for preparing alpha-semi-hydrated gypsum directly by desulfurized gypsum slurry |
| CN101302029A (en) * | 2008-06-26 | 2008-11-12 | 武汉科技大学 | Method for preparing alpha-hemihydrate gypsum with desulfurated gypsum |
-
2020
- 2020-01-15 CN CN202010043588.4A patent/CN111187016B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1513766A (en) * | 2003-06-06 | 2004-07-21 | 浙江大学 | Techlogogy for making alpha semi-water desulfur gypsum using normal pressure salt solution method |
| CN2813074Y (en) * | 2005-08-16 | 2006-09-06 | 孙克勤 | Gypsum slurry dewatering device in wet-process flue gas desulfurizing system |
| CN101182150A (en) * | 2007-11-09 | 2008-05-21 | 浙江大学 | Industrial crystallization technique for preparing alpha-semi-hydrated gypsum directly by desulfurized gypsum slurry |
| CN101302029A (en) * | 2008-06-26 | 2008-11-12 | 武汉科技大学 | Method for preparing alpha-hemihydrate gypsum with desulfurated gypsum |
Non-Patent Citations (1)
| Title |
|---|
| 杨旭中: "《燃煤电厂脱硫装置》", 30 June 2006, 中国电力出版社 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111187016B (en) | 2022-04-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100335154C (en) | Magnesium oxide flue gas desulfurization and outgrowth thick-slurry method oxidation reclaim process | |
| WO2011041956A1 (en) | Method for preparing manganese sulfate monohydrate by desulfurizing fume with middle-low grade manganese dioxide ore | |
| CN114854457B (en) | Decarbonization and desulfurization method for mixed gas containing combustible gas | |
| CN1939840A (en) | Tail gas treatment and reutilization for calcium carbide stove | |
| JP2023530366A (en) | Quicklime production process and system with reduced carbon emissions | |
| JPH06226042A (en) | Method for removal of sulfur dioxide from heated gaseous stream containing sulfur dioxide and for production of alpha type calcined gypsum | |
| CN111187016B (en) | System and process for preparing high-strength alpha-semi-hydrated gypsum from desulfurized gypsum and product thereof | |
| CN103601630A (en) | Method utilizing calcium carbide slag and carbon monoxide to synthesize calcium formate | |
| CN109422641B (en) | Continuous production method for preparing calcium formate from yellow phosphorus tail gas | |
| CN218962222U (en) | System for recycling ammonia and by-product active calcium through ammonia-calcium desulfurization | |
| CN110563110A (en) | Production process of polyaluminum chloride | |
| CN109095731A (en) | A kind of system based on magnesium processes desulfurization wastewater high-purity magnesium hydroxide | |
| CN115006982A (en) | Method for desulfurizing and carbon-fixing coal-fired flue gas by using carbide slag slurry | |
| CN214891287U (en) | Recycling device for purifying salt-making mother liquor slurry by flue gas method | |
| CN209338324U (en) | A kind of system based on magnesium processes desulfurization wastewater high-purity magnesium hydroxide | |
| CN201932918U (en) | Device for producing nano calcium carbonate by using quicklime | |
| CN103848445A (en) | Technique for preparing magnesium sulfate heptahydrate and concentrated sulfuric acid from liquid sulfur dioxide combined with sulfur dioxide | |
| CN1070167A (en) | Preparing potassium manganate by three-phase pressurization continuous oxidation | |
| CN211169850U (en) | Sulfur dioxide resource recycling system | |
| CN217888309U (en) | Combined flotation system for removing impurities and whitening ardealite | |
| CN111003692B (en) | Sulfur dioxide recycling system and method | |
| CN209940486U (en) | System for producing baking soda from caprolactam caustic sludge | |
| CN216878716U (en) | Auxiliary facility of active coke desulfurization and denitrification equipment | |
| CN215288069U (en) | System for SRG washing wastewater catalytic desalination | |
| CN104860338A (en) | Method for extracting alumina from fly ash through sulfo ammonium salt mixing medium system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20200522 Assignee: ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION ENGINEERING CO.,LTD. Assignor: ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION TECHNOLOGY Co.,Ltd. Contract record no.: X2023330000964 Denomination of invention: Preparation of high-strength desulfurization gypsum a- The system, process, and products of hemihydrate gypsum Granted publication date: 20220429 License type: Common License Record date: 20231227 |
|
| EE01 | Entry into force of recordation of patent licensing contract |