CN108751233B - Method for improving sodium bicarbonate crystal size - Google Patents
Method for improving sodium bicarbonate crystal size Download PDFInfo
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- CN108751233B CN108751233B CN201811011839.XA CN201811011839A CN108751233B CN 108751233 B CN108751233 B CN 108751233B CN 201811011839 A CN201811011839 A CN 201811011839A CN 108751233 B CN108751233 B CN 108751233B
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- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 title claims abstract description 402
- 229910000030 sodium bicarbonate Inorganic materials 0.000 title claims abstract description 196
- 235000017557 sodium bicarbonate Nutrition 0.000 title claims abstract description 195
- 239000013078 crystal Substances 0.000 title claims abstract description 163
- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000007788 liquid Substances 0.000 claims abstract description 203
- 238000001816 cooling Methods 0.000 claims abstract description 106
- 239000000243 solution Substances 0.000 claims abstract description 88
- 239000002002 slurry Substances 0.000 claims abstract description 80
- 239000002994 raw material Substances 0.000 claims abstract description 54
- 239000012047 saturated solution Substances 0.000 claims abstract description 49
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims abstract description 28
- 239000000110 cooling liquid Substances 0.000 claims abstract description 10
- 229920006395 saturated elastomer Polymers 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 abstract description 62
- 239000000047 product Substances 0.000 description 50
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 26
- 239000007789 gas Substances 0.000 description 19
- 238000001035 drying Methods 0.000 description 18
- 230000008569 process Effects 0.000 description 17
- 238000004519 manufacturing process Methods 0.000 description 16
- 238000000926 separation method Methods 0.000 description 15
- 239000003513 alkali Substances 0.000 description 14
- 238000002425 crystallisation Methods 0.000 description 13
- 230000008025 crystallization Effects 0.000 description 13
- 238000009826 distribution Methods 0.000 description 13
- 229910000029 sodium carbonate Inorganic materials 0.000 description 12
- 235000017550 sodium carbonate Nutrition 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 10
- 230000000149 penetrating effect Effects 0.000 description 10
- 238000003763 carbonization Methods 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 5
- 238000010276 construction Methods 0.000 description 5
- 238000000746 purification Methods 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 4
- 238000007873 sieving Methods 0.000 description 4
- 230000008719 thickening Effects 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 3
- 239000012527 feed solution Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000004806 packaging method and process Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000012216 screening Methods 0.000 description 3
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 206010039509 Scab Diseases 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000005262 decarbonization Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 238000005243 fluidization Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
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- 230000001788 irregular Effects 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 230000009711 regulatory function Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D7/00—Carbonates of sodium, potassium or alkali metals in general
- C01D7/38—Preparation in the form of granules, pieces or other shaped products
- C01D7/40—Influencing the crystallisation process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Fodder In General (AREA)
Abstract
The invention discloses a method for improving the crystal size of sodium bicarbonate, which comprises the following steps: preparing a saturated solution or a supersaturated solution of sodium bicarbonate; and introducing a saturated solution or a supersaturated solution of sodium bicarbonate into the device for increasing the crystal size of sodium bicarbonate through a raw material liquid inlet. The device for improving the crystal size of the sodium bicarbonate comprises a tank body and a central return pipe; the tank body is provided with a raw material liquid inlet, a crystal slurry outlet, a circulating cooling liquid axial flow pump outlet and an overflow port. The outlet of the circulating cooling feed liquid axial flow pump is arranged at the middle upper part of the tank body and is used for leading out and cooling the feed liquid in the tank body; the central return pipe is used for introducing the cooled feed liquid into the tank body, and the outlet of the cooling feed liquid return pipe of the central return pipe is arranged at the middle lower part of the tank body, so that the feed liquid is cooled circularly, and a sodium bicarbonate product with the particle size of 180-380 mu m is prepared to meet the requirement on the sodium bicarbonate product with the large particle size.
Description
Technical Field
The invention belongs to the technical field of sodium bicarbonate production, and particularly relates to a device and a method for improving the crystal grain size of sodium bicarbonate.
Background
Sodium Bicarbonate, often called baking soda, also called Sodium Bicarbonate, is a white or opaque monoclinic crystal, known as Sodium Bicarbonate, with the chemical formula NaHCO3And has certain solubility in water. Sodium bicarbonate is an important inorganic chemical product and is widely applied to the fields of chemical industry, light industry, medicine, textile, food, fine chemical industry and the like.
China is an important production country of sodium bicarbonate, and the scale of more than million tons is formed up to now. However, most of the traditional sodium bicarbonate is prepared by soda ash carbonation method, the main raw materials are soda ash and carbon dioxide, and the chemical reaction formula is as follows: na (Na)2CO3(aq)+CO2(g)+H2O(l)＝2NaHCO3(s)。
The key process of preparing sodium bicarbonate by carbonating soda ash is the carbonating of soda ash, the key equipment is a carbonating tower, which is surrounded by the carbonating operation, besides the preparation of necessary raw material liquid and raw material gas, a series of complicated auxiliary production processes such as purification treatment are required. The process mainly comprises the following steps: preparing and purifying a soda saturated solution; CO22Preparing, purifying and compressing gas; carbonation reaction and crystal precipitation; treating carbonized tail gas; taking out the crystallization suspension to be thick and separated; drying, screening and packaging the wet sodium bicarbonate crystals. Its main production equipment includes soda dissolving tank, wet decomposing tower, clarifying filter, carbonizing tower set, tail gas washing tower, thickener, centrifugal machine, airflow drying pipe, sieving machine and packing machine. In addition to the use for the preparation of CO2A decarbonization analysis system of raw gas or a series of auxiliary equipment such as a lime kiln, a dust remover, a compressor and the like.
The production steps of the traditional process mainly comprise: preparing solid sodium carbonate or sodium carbonate solution serving as a sodium carbonate raw material meeting the requirement into a sodium carbonate supersaturated solution reaching the required index (a high-temperature wet decomposition process needs to be added when the content of sodium bicarbonate is high), clarifying and purifying the sodium carbonate supersaturated solution, pumping the sodium carbonate supersaturated solution into a carbonization tower group (3 towers or 4 towers are commonly used for alternate operation/cleaning), and mixing the obtained CO with the prepared CO subjected to dust removal and purification2Compressing the raw material gas, and performing a carbonation reaction in a countercurrent manner to generate sodium bicarbonate; with the continuous reaction and the further reduction of the temperature, the sodium bicarbonate is gradually separated out from the solution in a crystallization form after reaching the supersaturation; taking out the suspension containing the sodium bicarbonate crystals, separating, drying, screening and packaging to prepare a solid sodium bicarbonate product. The sodium bicarbonate prepared by soda carbonation method is needle-shaped irregular powder, and has small hardness and fine granularity, and the granularity is usually less than 100 μm. This is forSome enterprises with special requirements on the particle size can not meet the requirements of sodium bicarbonate prepared by the traditional soda carbonation method if sodium bicarbonate products with the particle size of 150-300 mu m or even larger particle size are required.
Disclosure of Invention
The invention provides a device and a method for improving the crystal particle size of sodium bicarbonate, aiming at the problems that the particle size of sodium bicarbonate prepared by the traditional soda carbonate method is small and the application of the sodium bicarbonate in a certain particle size requirement range is limited.
The invention also provides a method for improving the crystal size of sodium bicarbonate, which uses a device for improving the crystal size of sodium bicarbonate to recrystallize sodium bicarbonate, and comprises the following steps:
preparing a saturated solution or a supersaturated solution of sodium bicarbonate;
introducing said saturated or supersaturated solution of sodium bicarbonate into said means for increasing the crystal size of sodium bicarbonate through said feed solution inlet;
the device for improving the crystal size of the sodium bicarbonate comprises a tank body and a central return pipe;
the tank body is provided with a raw material liquid inlet, a crystal slurry outlet, a circulating cooling liquid axial flow pump outlet and an overflow port;
the raw material liquid inlet is used for introducing a saturated solution or a supersaturated solution of sodium bicarbonate;
the crystal slurry outlet is used for leading the crystal slurry out of the tank body;
the outlet of the circulating cooling feed liquid axial flow pump is arranged at the middle upper part of the tank body and is used for leading out and cooling the feed liquid in the tank body;
the overflow port is arranged at the top of the tank body and used for discharging excessive feed liquid in the tank body;
the central return pipe is used for introducing cooled feed liquid into the tank body, and a cooling feed liquid return pipe outlet of the central return pipe is arranged at the middle lower part of the tank body.
In one embodiment, the crystal slurry outlet is arranged on the tank body opposite to the raw material liquid inlet.
In one embodiment, the raw material liquid inlet is arranged at 1/4-1/2 of the height of the tank body.
In one embodiment, the central return pipe is arranged in the tank, and the cooling feed liquid return pipe outlet of the central return pipe is lower than the raw material liquid inlet.
In one embodiment, the outlet of the axial flow pump of the circulating cooling feed liquid is arranged at the top of the tank body, and the outlet of the cooling feed liquid return pipe of the central return pipe is arranged at the bottom of the tank body.
In one embodiment, the device for increasing the crystal size of the sodium bicarbonate further comprises a driver, and the driver provides driving force for the circulating cooling feed liquid to be led out of the tank body.
In one embodiment, the temperature difference between the saturated solution or the supersaturated solution entering the device and the feed liquid entering the central return pipe after cooling is 5-25 ℃.
In one embodiment, the temperature of the saturated solution or the supersaturated solution is 50-70 ℃.
The method for improving the crystal size of the sodium bicarbonate comprises the steps that a saturated solution or a supersaturated solution of the sodium bicarbonate enters a tank body and then is converged with a solution in the tank body, wherein sodium bicarbonate crystal seeds are added in advance, the solution is led out of a system together through a circulating cooling feed liquid axial flow pump, and the solution returns to the tank body from a central return pipe after cooling is completed. With the continuous cooling of the feed liquid, the feed liquid in the tank is in a fluidized state from bottom to top. In the contact process of the cooled feed liquid and the original sodium bicarbonate seed crystal in the tank, the supersaturation degree gradually disappears, the crystal continuously grows, and a fluidized crystal slurry layer of the sodium bicarbonate is formed at the lower part of the tank. The raw material liquid continuously enters, the circulating cooling is continuously carried out, and the crystallization is continuously grown. When the crystals grow to the target particle size, the crystals are led out from the crystal slurry outlet, and sodium bicarbonate products with various target particle sizes are prepared through the processes of thickening separation, drying, sieving classification and the like. According to the device, crystals are continuously grown to a target particle size by passing a sodium bicarbonate saturated solution or a supersaturated solution through a crystal slurry layer through circulating cooling, so that a sodium bicarbonate product with the particle size of 180-380 mu m is prepared, and the requirement on a sodium bicarbonate product with a large particle size is met.
Drawings
FIG. 1 is a schematic diagram of an apparatus for increasing the crystal size of sodium bicarbonate according to an embodiment of the present invention;
FIG. 2 is a flow chart of a process for preparing sodium bicarbonate products by a traditional carbonation method;
FIG. 3 is a process flow chart of the method for increasing the crystal size of sodium bicarbonate to prepare sodium bicarbonate products.
Wherein, 110-tank body; 111-feed solution inlet; 112-crystal slurry outlet; 113-circulating cooling feed liquid axial flow pump outlet; 114-an overflow port; 120-central return pipe; 121-outlet of cooling feed liquid reflux pipe; 200-inlet of central return pipe of circulating cooling feed liquid.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1 and 3, a method for increasing the crystal size of sodium bicarbonate according to an embodiment of the present invention uses an apparatus for increasing the crystal size of sodium bicarbonate to recrystallize sodium bicarbonate, and includes the following steps:
preparing a saturated solution or a supersaturated solution of sodium bicarbonate;
a saturated or supersaturated solution of sodium bicarbonate is introduced into the means for increasing the particle size of the sodium bicarbonate through feed inlet 111.
The device for improving the crystal size of the sodium bicarbonate comprises a tank body 110 and a central return pipe 120, wherein the tank body 110 is provided with a raw material liquid inlet 111, a crystal slurry outlet 112, a circulating cooling liquid axial flow pump outlet 113 and an overflow port 114. The raw material liquid inlet 111 is used for introducing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal slurry outlet 112 is used for leading the crystal slurry out of the tank body 110, the circulating cooling feed liquid axial flow pump outlet 113 is arranged at the middle upper part of the tank body 110 and is used for leading the feed liquid in the tank body 110 out for cooling, the overflow port 114 is arranged at the top of the tank body 110 and is used for discharging the excessive feed liquid in the tank body 110, the central return pipe 120 is used for leading the cooled feed liquid into the tank body 110, and the cooling feed liquid return pipe outlet 121 of the central return pipe 120 is arranged at the middle lower part of the tank body.
In the method for improving the crystal size of the sodium bicarbonate, the feed liquid in the tank body 110 is led out through the circulating cooling feed liquid axial flow pump outlet 113, is cooled by external cooling equipment, and then returns to the tank body 110 from the cooling feed liquid return pipe outlet 121 of the central return pipe 120 through the circulating cooling feed liquid central return pipe inlet 200. After the sodium bicarbonate saturated solution or supersaturated solution introduced from the raw material solution inlet 111 is cooled, it passes through the fluidized layer containing sodium bicarbonate seed crystals, and the supersaturation degree disappears, so that crystals grow. With the continuous introduction of the raw material liquid, the solution in the tank is circularly cooled, the supersaturation degree disappears continuously when the cooled material liquid passes through the fluidized crystal slurry layer, and the crystal grows continuously. When the crystals grow to the target particle size, the crystals can be led out from the crystal slurry outlet 112, and sodium bicarbonate products with various target particle sizes are prepared through the processes of thickening separation, drying, sieving classification and the like. According to the device, crystals are continuously grown to a target particle size by passing a sodium bicarbonate saturated solution or a supersaturated solution through a crystal slurry layer through circulating cooling, so that a sodium bicarbonate product with the particle size of 180-380 mu m is prepared, and the requirement on a sodium bicarbonate product with a large particle size is met.
The method for improving the crystal size of the sodium bicarbonate adopts a physical recrystallization method in the sodium bicarbonate crystallization process, realizes the granulation function of the sodium bicarbonate crystallization only by using two main devices, namely a device for improving the crystal size of the sodium bicarbonate and an alkali dissolving tank, and has simple flow and convenient operation. Compared with the traditional carbonation reaction process, the method replaces the traditional carbonation tower group with 3 towers or 4 towers in grouping and alternating operation, cancels the complex switching process and obviously improves the equipment utilization rate. Because of no carbonation reaction of alkali liquor, the system does not need CO2The participation of raw material gas eliminates complicated and lengthy production processes such as gas making, purification, compression, carbonization, tail gas treatment and the like and a series of related equipment, and lightens the environmentThe pressure is maintained, the constraint that independent factory building is not easy is eliminated, the restriction of relevant devices on the production energy of the sodium bicarbonate is avoided, the process flow is greatly simplified, the project land is reduced, the construction investment is saved, and the risk and the operation difficulty of project construction are greatly reduced.
More closely, the device that improves sodium bicarbonate crystal grain size has stronger buffering regulatory function, can produce the sodium bicarbonate product of different particle size ranges through the regulation and control of technological parameter, and then satisfies different users' special demand.
Referring to fig. 2, in the conventional process for preparing sodium bicarbonate by using a carbonization tower, carbonization and crystallization are simultaneously performed in the carbonization tower, and precipitated sodium bicarbonate crystals are almost needle-shaped, so that coarse crystal particles are difficult to prepare, and the application of sodium bicarbonate products with certain particle size is limited. In addition, because the carbonization tower plays a dual role of chemical reaction and crystallization, scabbing in the production process is inevitable, and in order to realize the production continuity, the operation mode of alternately carrying out operation/cleaning on the tower grouping has to be used, so that the carbonization system has dense pipelines, complicated control and complex operation.
The method for improving the crystal size of the sodium bicarbonate enables the sodium bicarbonate saturated solution or supersaturated solution to continuously grow and crystallize by utilizing the fluidized crystal slurry layer, greatly reduces the scabbing phenomenon, realizes the production continuity and reduces the production control difficulty for preparing the sodium bicarbonate crystal with large particle size.
Further, in the case of sodium bicarbonate by carbonation, soda ash and CO are used for the carbonation reaction2Are two essential basic raw materials, and CO2The raw material gas is obtained either by attaching to a decarbonization section of an ammonia synthesis device or by building a lime kiln to produce gas. The system not only has complicated process and long flow and large system operation difficulty, but also has the production capacity of the device often influenced by the CO of the whole plant2Balancing and restricting an air source; and the complicated and fussy gas making and the purification treatment of various tail gases brought by the method not only have high investment and large construction land, but also are closely related to regional environmental protection, thereby causing great difficulty in project site selection. In CO2On the premise of deficient gas source, limited construction site and high environmental protection requirement, the device for improving the crystallization particle size of the sodium bicarbonate can prepare the sodium bicarbonate product with large particle size only by a physical mode without depending on a CO2 gas source, can independently build a plant to avoid the site limitation, can not generate harmful gas or excessive sewage, and reduces the environmental protection pressure and the maintenance cost.
As an alternative embodiment, because the circulating cooling liquid axial flow pump outlet 113 of the device is arranged at the middle upper part of the tank body 110, and the cooling liquid return pipe outlet 121 of the central return pipe 120 is arranged at the middle lower part of the tank body 110, the liquid in the tank body 110 naturally forms a flow from bottom to top, and a crystal slurry layer is formed at the lower part of the tank body due to the gravity relationship. The crystal slurry outlet 112 and the raw material liquid inlet 111 are respectively arranged on the tank body 110 and are oppositely arranged on two sides of the tank body 110, so that on one hand, the problem that the crystal slurry layer formed in the tank is disturbed by saturated solution or supersaturated solution introduced from the inlet 111 to influence the growth of crystals is avoided; on the other hand, a stable crystal slurry layer is kept, so that the extraction of the well-grown sodium bicarbonate crystal is more convenient. Alternatively, the slurry outlet 112 and the raw material liquid inlet 111 may be disposed on the wall of the tank 110 in other manners, such as dispersing the raw material liquid inlet 111 on the wall of the tank 110 to avoid disturbance to the material liquid in the tank 110, thereby affecting the stability of the slurry layer.
As an alternative embodiment, the raw material liquid inlet 111 is arranged at 1/4-1/2 of the height of the tank body 110, so that the saturated solution or the supersaturated solution of the sodium bicarbonate can have a larger flowing distance, and the saturated solution or the supersaturated solution of the sodium bicarbonate can be fully mixed with the raw material liquid in the tank body 110.
As an alternative embodiment, central return pipe 120 is disposed inside tank 110, and cooling feed liquid return pipe outlet 121 of central return pipe 120 is lower than feed liquid inlet 111. Because the outlet 121 of the cooling feed liquid return pipe of the central return pipe 120 is lower than the inlet 111 of the raw material liquid, when the feed liquid flows in the tank 110, the cooled feed liquid enters the tank 110 from the outlet 121 of the cooling feed liquid return pipe and flows from bottom to top, so as to be mixed with the saturated solution or supersaturated solution of sodium bicarbonate entering from a higher position, so that the temperature of the solution is reduced, and the solution is further crystallized and grown into crystals with larger grain diameter in a crystal slurry layer. In other embodiments, center return line 120 may be disposed outside tank 110 and extend into tank 110 through the bottom of tank 110 such that cooling feed liquid return line outlet 121 of center return line 120 is located within tank 110 and below feed liquid inlet 111.
Optionally, the outlet 113 of the axial-flow pump for circulating cooling liquid is disposed at the top of the tank 110, and the outlet 121 of the return pipe for cooling liquid of the central return pipe 120 is disposed at the bottom of the tank 110, so that the liquid in the tank 110 flows in the whole height of the tank 110, and the liquid in the tank 110 sufficiently drives the introduced saturated solution or supersaturated solution of sodium bicarbonate to mix.
Alternatively, the tank 110 may be a cylindrical tank 110 with different diameters, and preferably, the inner diameter of the tank 110 is gradually increased from bottom to top, so that the rising speed of the feed liquid in the tank 110 is gradually reduced, thereby facilitating the layering of crystals and liquid.
As an alternative embodiment, the device for increasing the crystal size of sodium bicarbonate further comprises a driver, and the driver provides driving force for the circulating cooling feed liquid to be led out of the tank body 110. Alternatively, the driver may be an axial flow pump. The axial flow pump pumps the feed liquid in the tank 110 to exchange heat with the external cooling device to cool the feed liquid, and then the cooled feed liquid is returned to the tank 110 through the central return pipe 120, thereby forming the circulating cooling of the feed liquid in the tank 110 and the external cooling device and the fluidization of the feed liquid in the tank 110.
In the device for improving the crystallization particle size of the sodium bicarbonate, the feed liquid in the tank body 110 is led out from the circulating cooling feed liquid axial flow pump outlet 113, cooled and then returned to the tank body 110 from the cooling feed liquid return pipe outlet 121 of the central return pipe 120, the cooled feed liquid enables the lower part of the tank body to form a sodium bicarbonate crystallization fluidized layer, the sodium bicarbonate saturated solution or supersaturated solution entering from the feed liquid inlet 111 contacts with the feed liquid layer containing the seed crystals, the supersaturation degree disappears, and the crystals continuously grow. With the continuous introduction of the sodium bicarbonate saturated solution or supersaturated solution from the raw material solution inlet 111, the cooled material solution is continuously circulated in the tank 110, and the supersaturation degree gradually disappears when the sodium bicarbonate saturated solution or supersaturated solution passes through the crystal slurry layer, so that the crystal is continuously grown. When the crystals grow to the target particle size, the crystals can be led out from the crystal slurry outlet 112, and the sodium bicarbonate product with the target particle size is prepared through the processes of thickening separation, drying, sieving classification and the like. The device enables crystals of the crystal slurry layer to continuously grow to a target particle size when the sodium bicarbonate saturated solution or supersaturated solution continuously flows through the crystal slurry layer, so that sodium bicarbonate crystals with larger particle size are prepared, and a sodium bicarbonate product with the particle size of 180-380 mu m is obtained.
The processes of thick separation, drying, screening and grading, mixing and packaging and the like can be carried out by adopting the traditional process, and the influence on the preparation of the sodium bicarbonate product with large particle size is small.
As shown in fig. 2 and fig. 3, compared with the conventional carbonation reaction process, the method for increasing the sodium bicarbonate crystal size according to the present invention replaces the conventional carbonation tower group with a group of 3 towers or a group of 4 towers and performs a grouping and alternating operation, thereby eliminating a complicated switching process and significantly increasing the equipment utilization rate. In addition, the system does not need CO due to no carbonation reaction of alkali liquor2The participation of the raw material gas cancels the tedious and lengthy production processes of gas making, purification, compression and carbonization, tail gas treatment and the like, lightens the environmental protection pressure, gets rid of the constraint of difficult independent plant construction, avoids the restriction of related devices on the production energy of the sodium bicarbonate, greatly simplifies the process flow, and has simple flow and convenient operation.
Optionally, the saturated solution or supersaturated solution of sodium bicarbonate is prepared by taking powdered sodium bicarbonate as a raw material, adding a certain amount of water into an alkali dissolving tank, and heating for dissolving. Alternatively, the feed liquid recovered from the overflow port 114 may be used to replace part of the water to prepare a saturated solution or a supersaturated solution of sodium bicarbonate, and the filtrate obtained by separating the magma through thickening may be used to replace part of the water to prepare a saturated solution or a supersaturated solution of sodium bicarbonate, so as to improve the utilization efficiency of the raw materials and the yield of the large-particle-size sodium bicarbonate product. The saturated solution or supersaturated solution of sodium bicarbonate is pumped into the tank 110 through the raw material liquid inlet 111, the saturated solution or supersaturated solution of sodium bicarbonate in the tank 110 is continuously sent into a cooler arranged outside through the circulating cooling feed liquid axial flow pump outlet 113 by the top axial flow pump for cooling, and is returned into the tank 110 through the central return pipe 120. With the circulation of the large amount of the feed liquid, the feed liquid containing the seed crystal is mixed with the saturated solution or supersaturated solution of sodium bicarbonate entering the tank 110, and a crystal slurry layer is formed. When the crystal grain size of the crystal slurry layer reaches the target grain size, the crystal slurry layer can be led out of the tank body 110 through the crystal slurry outlet 112. Alternatively, since the raw material liquid inlet is provided on the tank 110 opposite to the slurry outlet 112, the flow rate of the raw material liquid inlet 111 and the slurry outlet 112 is controlled so that the sodium bicarbonate slurry containing the target particle size can be continuously drawn out of the tank 110.
As an alternative embodiment, the temperature difference between the solution in the tank and the feed solution entering central return line 120 after cooling is 1 ℃. The temperature difference between the solution in the tank before cooling and the feed liquid entering the central return pipe 120 after cooling will affect the crystallization rate and the particle size, the larger the temperature difference is, the faster the crystallization rate is, but the smaller the particle size of the formed crystal is; the smaller the temperature difference, the slower the crystallization rate, but crystals of larger particle size can be formed. Through a large number of researches and experimental verification, when the temperature difference before and after the feed liquid is cooled is 1 ℃, sodium bicarbonate crystals with the particle size larger than 150 meshes can be formed in a large proportion, and particularly when the temperature difference is smaller than 1 ℃, the proportion of sodium bicarbonate products with large particle size is higher.
Further optionally, the temperature of the saturated solution or the supersaturated solution is 50-70 ℃. The temperature of the saturated or supersaturated solution affects the amount of sodium bicarbonate dissolved in the solution, with higher temperatures causing more sodium bicarbonate to be dissolved, but at temperatures too high, the rate of decomposition of sodium bicarbonate to sodium carbonate will increase substantially. The temperature of the saturated solution or the supersaturated solution is controlled to be 50-70 ℃, so that the content of the sodium bicarbonate in the solution is as much as possible, the decomposition rate of the sodium bicarbonate can be reduced as much as possible, the quality of the prepared sodium bicarbonate product is higher, and the comprehensive cost is lower.
The research finds that the flow ratio of the axial flow pump outlet 113 of the circulating cooling feed liquid to the raw material liquid inlet 111 influences the granularity of the prepared sodium bicarbonate product, and the larger the flow ratio is, the more fully the sodium bicarbonate saturated solution or supersaturated solution is contacted with crystal nuclei in the feed liquid, and the larger the crystals are formed.
Example 1
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (particle size less than 100 μm) powdery sodium bicarbonate raw material into alkali dissolving tank, adding water, maintaining the temperature of mother liquor in the tank at 60 deg.C, and dissolving the powdery sodium bicarbonate raw material in water sufficiently to form saturated solution. Saturated sodium bicarbonate solution is only 0.16m3H, the small flow is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.13m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid can be recycled for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 2
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (particle size less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 50 deg.C, and dissolving the powdery sodium bicarbonate in water to form supersaturated solution. Saturated sodium bicarbonate solution at 0.12m3Flow rate of/h is introduced into the tank body 110 with the feed liquid temperature of 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3H, the feed liquid in the tank 110 is led out, cooled to below 40 ℃ by an external cooling device and returned to the tank 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120 to be slightly lower than the feed liquid in the tank 110The temperature of the feed liquid in the tank body 110 passes through the crystal slurry layer, the supersaturation degree disappears, and the crystal grows up to 0.10m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 3
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (particle size less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 70 deg.C, and dissolving the powdery sodium bicarbonate in water to obtain saturated solution. Saturated sodium bicarbonate solution at 0.20m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.17m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 4
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (particle size less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 deg.C, and dissolving the powdery sodium bicarbonate in water to obtain saturated solution. Saturated sodium bicarbonate solution at 0.16m3Flow rate of/h is introduced into the tank 110 at a feed temperature of about 40 deg.CThe circulating cooling flow rate of the outlet 113 of the circulating cooling feed liquid axial flow pump is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than that of the feed liquid in the tank body 110, and eliminating supersaturation and growing crystals. At 0.13m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 5
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.16m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.12m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 6
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
In dissolving alkaliThe powdery sodium bicarbonate raw material with 150 meshes (the granularity is less than 100 mu m) is added into the tank, water is added and the tank is heated to 60 ℃, so that the powdery sodium bicarbonate is fully dissolved in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.16m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.15m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 7
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.16m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through a crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.14m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing saturated solution or supersaturated solution of sodium bicarbonate, and the crystal mush is further subjected to thick separation and drying to obtain granular sodium bicarbonateThe particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 8
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.12m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, and penetrating through a crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, wherein the supersaturation degree disappears, and the crystal grows. At 0.11m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 9
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.14m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 4 ℃ and 0 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through a crystal slurry layer at a temperature slightly lower than that of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals.At 0.12m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 10
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.18m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.15m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Example 11
Sodium bicarbonate crystals were prepared in an apparatus for increasing the sodium bicarbonate crystal size as shown in figure 1.
Adding 150 mesh (granularity less than 100 μm) powdery sodium bicarbonate raw material into an alkali dissolving tank, adding water, heating to 60 ℃, and fully dissolving the powdery sodium bicarbonate in the water to form a supersaturated solution. Saturated sodium bicarbonate solution at 0.16m3Flow rate of/h is introduced into the tank body 110 with the temperature of the feed liquid being about 40 ℃, and the circulating cooling flow rate of the circulating cooling feed liquid axial flow pump outlet 113 is set to be 2.0m3And h, leading out the feed liquid in the tank body 110, cooling the feed liquid to be below 40 ℃ through external cooling equipment, returning the feed liquid into the tank body 110 through a cooling feed liquid return pipe outlet 121 at the bottom of the central return pipe 120, penetrating through the crystal slurry layer at a temperature slightly lower than the temperature of the feed liquid in the tank body 110, and eliminating supersaturation degree and growing crystals. At 0.13m3The flow rate of the slurry/h leads the slurry out from a slurry outlet 112, and the excessive clear liquid in the tank body 110 flows out from an overflow port 114 at the top. The clear liquid is recovered and used for preparing a saturated solution or a supersaturated solution of sodium bicarbonate, the crystal mush is further subjected to thick separation and drying to prepare a granular sodium bicarbonate product, and the particle size distribution of the granular sodium bicarbonate product is shown in table 1.
Table 1 particle size distribution of sodium bicarbonate product prepared in example
As can be seen from Table 1, the device for increasing the crystal size of sodium bicarbonate can be used for preparing sodium bicarbonate products with the particle size of more than 150 meshes, and the yield is high and is more than 99%.
Further, as can be seen from comparison of examples 1, 6 and 7, the flow rate of the magma out of the tank 110 has a certain relationship with the particle size distribution of the prepared sodium bicarbonate, and the smaller the flow rate of the magma out of the tank 110 is, the more sodium bicarbonate products with larger particle sizes tend to be formed; the greater the flow rate of the slurry out of the tank 110, the more likely a larger particle size sodium bicarbonate product will be formed.
Furthermore, comparing examples 1 and 8-11, it can be found that the flow ratio of the raw material liquid inlet 111 to the circulating cooling liquid axial-flow pump outlet 113 has a certain influence on the particle size of the prepared sodium bicarbonate product, and the larger the flow ratio of the circulating cooling liquid axial-flow pump outlet 113 to the raw material liquid inlet 111 is, the higher the proportion of the sodium bicarbonate product with larger particle size is; the smaller the flow ratio of the circulating cooling feed liquid axial-flow pump outlet 113 to the raw material liquid inlet 111 is, the higher the proportion of the sodium bicarbonate product with smaller particle size is; however, the yield of the product with the particle size of more than 150 meshes can be maintained to be more than 97 percent in general.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (8)
1. A method for increasing the crystal size of sodium bicarbonate is characterized in that the method for increasing the crystal size of sodium bicarbonate uses a device for increasing the crystal size of sodium bicarbonate to recrystallize sodium bicarbonate, and comprises the following steps:
preparing a saturated solution or a supersaturated solution of sodium bicarbonate;
introducing said saturated or supersaturated solution of sodium bicarbonate into said means for increasing the crystal size of sodium bicarbonate through a feed inlet (111);
the device for improving the crystal size of the sodium bicarbonate comprises a tank body (110) and a central return pipe (120);
the tank body (110) is provided with a raw material liquid inlet (111), a crystal slurry outlet (112), a circulating cooling liquid axial flow pump outlet (113) and an overflow port (114);
the raw material liquid inlet (111) is used for introducing a saturated solution or a supersaturated solution of sodium bicarbonate;
the crystal mush outlet (112) is used for leading the crystal mush out of the tank body (110);
the outlet (113) of the circulating cooling feed liquid axial flow pump is arranged at the middle upper part of the tank body (110) and is used for leading out and cooling the feed liquid in the tank body (110);
the overflow port (114) is arranged at the top of the tank body (110) and is used for discharging excessive feed liquid in the tank body (110);
the central return pipe (120) is used for introducing cooled feed liquid into the tank body (110), and a cooling feed liquid return pipe outlet (121) of the central return pipe (120) is arranged at the middle lower part of the tank body (110);
the outlet (121) of the cooling feed liquid return pipe of the central return pipe (120) is lower than the inlet (111) of the raw material liquid.
2. The method for increasing the crystal size of sodium bicarbonate according to claim 1, wherein the magma outlet (112) is arranged on the tank (110) opposite to the raw material liquid inlet (111).
3. The method for increasing the crystal size of sodium bicarbonate according to claim 2, wherein the raw material liquid inlet (111) is arranged at 1/4-1/2 of the height of the tank (110).
4. The method for increasing the crystal size of sodium bicarbonate according to claim 1, wherein the central return pipe (120) is disposed inside the tank (110).
5. The method for improving the crystal size of sodium bicarbonate according to claim 4, characterized in that the outlet (113) of the axial flow pump of the circulating cooling feed liquid is arranged at the top of the tank body (110), and the outlet (121) of the cooling feed liquid return pipe of the central return pipe (120) is arranged at the bottom of the tank body (110).
6. The method for increasing the crystal size of sodium bicarbonate according to claim 5, wherein the device for increasing the crystal size of sodium bicarbonate further comprises a driver, and the driver provides driving force for the circulating cooling feed liquid to be led out of the tank body (110).
7. The method for increasing the crystal size of sodium bicarbonate according to claim 1, wherein the temperature difference between the saturated solution or the supersaturated solution entering the device and the feed liquid entering the central return pipe (120) after cooling is 5-25 ℃.
8. The method for increasing the crystal size of sodium bicarbonate according to any of claims 1 to 7, wherein the temperature of the saturated or supersaturated solution is 50 to 70 ℃.
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| CN111943234A (en) * | 2020-08-13 | 2020-11-17 | 河北华晨药业有限公司 | Method for preparing medicinal sterile sodium bicarbonate granules with large particle size |
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| CN1849263A (en) * | 2004-08-24 | 2006-10-18 | 旭硝子株式会社 | Process for producing alkali metal bicarbonate |
| CN204319821U (en) * | 2014-12-02 | 2015-05-13 | 成都华西堂投资有限公司 | A kind of sodium acid carbonate crystallizer containing central tube |
| CN108358220A (en) * | 2018-03-07 | 2018-08-03 | 武汉德泽环保科技有限公司 | A kind of method and apparatus producing sodium bicarbonate |
| CN108439434A (en) * | 2018-03-07 | 2018-08-24 | 武汉德泽环保科技有限公司 | A kind of method and apparatus producing sodium bicarbonate |
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| CN1849263A (en) * | 2004-08-24 | 2006-10-18 | 旭硝子株式会社 | Process for producing alkali metal bicarbonate |
| CN204319821U (en) * | 2014-12-02 | 2015-05-13 | 成都华西堂投资有限公司 | A kind of sodium acid carbonate crystallizer containing central tube |
| CN108358220A (en) * | 2018-03-07 | 2018-08-03 | 武汉德泽环保科技有限公司 | A kind of method and apparatus producing sodium bicarbonate |
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Effective date of registration: 20210607 Address after: 224100 2nd floor, building 1, south of Weisan road and east of Jinger Road, Dafenggang Yanchang, Dafeng District, Yancheng City, Jiangsu Province Patentee after: JIANGSU BAIJIAN ENVIRONMENTAL PROTECTION TECHNOLOGY Co.,Ltd. Address before: Room 407, Lane 498, Renmin Road, Jiangdong District, Ningbo, Zhejiang 315000 Patentee before: Gu Zhenghong |
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