CN118079823A - Thiourea synthesis system and method for preparing thiourea - Google Patents
Thiourea synthesis system and method for preparing thiourea Download PDFInfo
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- CN118079823A CN118079823A CN202410466688.6A CN202410466688A CN118079823A CN 118079823 A CN118079823 A CN 118079823A CN 202410466688 A CN202410466688 A CN 202410466688A CN 118079823 A CN118079823 A CN 118079823A
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- China
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- thiourea
- mother liquor
- liquid
- tank
- water
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- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 title claims abstract description 495
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 247
- 238000003786 synthesis reaction Methods 0.000 title claims abstract description 83
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 79
- 238000000034 method Methods 0.000 title claims abstract description 31
- 239000012452 mother liquor Substances 0.000 claims abstract description 90
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 87
- 239000007788 liquid Substances 0.000 claims abstract description 74
- MYFXBBAEXORJNB-UHFFFAOYSA-N calcium cyanamide Chemical compound [Ca+2].[N-]=C=[N-] MYFXBBAEXORJNB-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000000843 powder Substances 0.000 claims abstract description 37
- 238000001816 cooling Methods 0.000 claims abstract description 29
- 238000001914 filtration Methods 0.000 claims abstract description 27
- 239000007789 gas Substances 0.000 claims abstract description 26
- 238000002425 crystallisation Methods 0.000 claims abstract description 19
- 230000008025 crystallization Effects 0.000 claims abstract description 19
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims abstract description 18
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims abstract description 17
- 230000001502 supplementing effect Effects 0.000 claims abstract description 10
- 238000001035 drying Methods 0.000 claims abstract description 8
- 238000006243 chemical reaction Methods 0.000 claims description 38
- 239000012224 working solution Substances 0.000 claims description 25
- 230000002194 synthesizing effect Effects 0.000 claims description 24
- 239000013078 crystal Substances 0.000 claims description 22
- 239000000706 filtrate Substances 0.000 claims description 22
- 239000012535 impurity Substances 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 15
- 238000003860 storage Methods 0.000 claims description 14
- YAECNLICDQSIKA-UHFFFAOYSA-L calcium;sulfanide Chemical compound [SH-].[SH-].[Ca+2] YAECNLICDQSIKA-UHFFFAOYSA-L 0.000 claims description 9
- 239000012295 chemical reaction liquid Substances 0.000 claims description 8
- 239000000047 product Substances 0.000 claims description 7
- 230000035484 reaction time Effects 0.000 claims description 7
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 6
- 239000000920 calcium hydroxide Substances 0.000 claims description 6
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 3
- 239000013589 supplement Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000000926 separation method Methods 0.000 abstract description 4
- 238000002360 preparation method Methods 0.000 abstract description 3
- 238000004064 recycling Methods 0.000 abstract description 3
- 239000004480 active ingredient Substances 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 9
- 239000012071 phase Substances 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- 239000000428 dust Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000010413 mother solution Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 239000002341 toxic gas Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000008396 flotation agent Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C335/00—Thioureas, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C335/02—Thiourea
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/04—Combinations of filters with settling tanks
- B01D36/045—Combination of filters with centrifugal separation devices
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0059—General arrangements of crystallisation plant, e.g. flow sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/02—Crystallisation from solutions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00002—Chemical plants
- B01J2219/00004—Scale aspects
- B01J2219/00006—Large-scale industrial plants
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of thiourea synthesis, in particular to a thiourea synthesis system and a thiourea preparation method. The thiourea synthesis system comprises a thiourea synthesis kettle, wherein the thiourea synthesis kettle is connected with a thiourea mother liquor collecting tank, a water adding pipeline, a hydrogen sulfide pipeline, a lime nitrogen powder pipeline and a filtering device, and the filtering device is sequentially connected with a cooling crystallization device and a centrifugal device; the centrifugal device is connected with a thiourea mother liquor tank which is connected with a thiourea mother liquor collecting tank and a water supplementing pipeline; the device also comprises a water ring vacuum pump, wherein the water ring vacuum pump is connected with the thiourea synthesis kettle, the thiourea mother liquid tank and a gas-liquid separator, and the gas-liquid separator is connected with the tail gas treatment device and the thiourea mother liquid collecting tank. The method comprises the following steps: adding water for the first time; lime nitrogen is added for the first time; introducing hydrogen sulfide; lime nitrogen is added again; filtering; cooling and crystallizing; centrifugal separation and drying; and recycling the thiourea mother liquor. The invention simultaneously utilizes the temperature of the thiourea mother liquor and the active ingredients, thereby reducing the energy consumption and improving the production efficiency.
Description
Technical Field
The invention relates to the technical field of thiourea synthesis, in particular to a thiourea synthesis system and a thiourea preparation method.
Background
Thiourea is an important chemical product, and can be used as a raw material for manufacturing medicines, dyes, resins, molding powder and the like, and also can be used as a vulcanization accelerator for rubber, a flotation agent for metal minerals and the like. The lime nitrogen method is an important method for producing thiourea, and the technological process of the lime nitrogen method is that water and lime nitrogen are added into a thiourea synthesis kettle for mixing, then H 2 S gas is added into the thiourea synthesis kettle for reaction to generate calcium hydrosulfide, then lime nitrogen is continuously added into a reaction kettle for heating reaction to generate thiourea, and finally thiourea crystals are obtained through cooling crystallization, centrifugal separation and drying links.
In the process for synthesizing thiourea by using a lime nitrogen method, because gaseous reactants are extremely toxic gases and solid reactants are powdery solids, a water ring vacuum pump is required to be connected with a thiourea synthesizing kettle in order to prevent the extremely toxic gases from leaking and provide power for feeding the powdery solids, and the thiourea synthesizing kettle is kept in a negative pressure state in the whole course in the reaction process. The water ring vacuum pump generally uses desalted water as working solution, during operation, the working solution is wrapped with gas phase medium pumped out from the thiourea synthesis kettle and enters a subsequent gas-liquid separator, after gas-liquid separation, the gas phase medium enters a tail gas treatment device for innocent treatment, and the liquid phase medium needs to be cooled by cooling equipment (such as a heat exchanger) and then enters the water ring vacuum pump as working solution for recycling.
However, on one hand, because the synthesis of thiourea is an exothermic reaction, the temperature of a gas-phase medium sucked by the water ring vacuum pump is generally 50-80 ℃, so that the working solution of the water ring vacuum pump is seriously heated, a large amount of cooling resources such as circulating water are consumed for cooling, and the energy consumption is high; on the other hand, as the working solution is recycled in the prior art, the impurities such as ammonia gas, hydrogen sulfide, calcium hydrosulfide, lime nitrogen dust and the like mixed in the gas-phase medium can be gradually enriched in the working solution, and after a period of circulation, the working solution is extremely easy to block pipelines and machine pumps and damage impellers, so that the use effect of the water ring vacuum pump is seriously influenced, and the service life of the water ring vacuum pump is shortened; in addition, the existing thiourea synthesis process can generate a large amount of low-temperature thiourea mother liquor, the thiourea mother liquor is saturated thiourea solution containing impurities, which remains after cooling crystallization and filtering separation of thiourea crystallization, and the thiourea mother liquor cannot be effectively recycled, so that resource waste is caused.
Disclosure of Invention
Aiming at the problems that a large amount of cooling resources are required to be consumed in the process of maintaining the negative pressure environment of a reaction kettle in the existing thiourea synthesis process by a lime nitrogen method to cool the working solution of a water ring vacuum pump, the energy consumption is high; impurity enrichment in the working solution circulation process shortens the service life of the water ring vacuum pump; the invention provides a thiourea synthesis system and a method for preparing thiourea, which can generate a large amount of low Wen Liuniao mother liquor, and the thiourea mother liquor cannot be recycled, so that the technical problem of resource waste is solved; the working solution is discontinuously circulated, the impurities are not enriched, and the service life of the water ring vacuum pump is prolonged; meanwhile, the available components in the thiourea mother liquor are fully recycled, so that the resource utilization rate is improved, and the production efficiency is improved.
In a first aspect, the invention provides a thiourea synthesis system, which comprises a thiourea synthesis kettle, wherein a first liquid inlet, a second liquid inlet, an air inlet and a powder feed inlet are arranged on the thiourea synthesis kettle, a discharge port is arranged at the bottom of the thiourea synthesis kettle, and a negative pressure air outlet is arranged at the top of the thiourea synthesis kettle; the first liquid inlet is connected with a water adding pipeline, the air inlet is connected with a hydrogen sulfide pipeline, the powder inlet is connected with a lime nitrogen storage tank through a lime nitrogen powder pipeline, and the discharge port is sequentially connected with a filtering device, a cooling crystallization device and a centrifugal device; the liquid outlet of the centrifugal device is connected with a thiourea mother liquor tank, the thiourea mother liquor tank is connected with a thiourea mother liquor collecting tank, and the thiourea mother liquor collecting tank is connected with a second liquid inlet; the thiourea mother liquid tank is connected with a water supplementing pipeline; still include the water ring vacuum pump, be provided with negative pressure air inlet, working solution inlet and mixed export on the water ring vacuum pump, negative pressure air inlet is connected with the negative pressure gas outlet, and the working solution inlet is connected with thiourea mother liquor jar, and mixed export is connected with gas-liquid separator, and gas outlet and the tail gas processing apparatus of gas-liquid separator are connected, and gas-liquid separator's liquid outlet is connected with thiourea mother liquor collecting vat.
Furthermore, the stirring device is arranged in the thiourea synthesis kettle, so that reactants can be stirred in the reaction process, and the reaction efficiency and the product yield are improved.
Further, the filtering device comprises a coarse filter and a fine filter which are sequentially connected, the filtering precision of the coarse filter is 15-30 mu m, the filtering precision of the fine filter is 0.5-10 mu m, the discharge port of the thiourea synthesis kettle is sequentially connected with the coarse filter and the fine filter, the reaction product of the thiourea synthesis kettle can be subjected to coarse filtration firstly to remove large-particle solids, then fine filtration is performed to further remove small-particle solids, and the filter is prevented from being blocked while the purity of thiourea in the subsequent link is improved.
In a second aspect, the present invention provides a method for preparing thiourea using the thiourea synthesis system described above, comprising the steps of:
(1) Adding water for the first time, adding water into the thiourea synthesis kettle by a water adding pipeline, and adding water into the thiourea mother liquor tank by a water supplementing pipeline;
(2) Firstly adding lime nitrogen, starting a water ring vacuum pump to enable the thiourea synthesis kettle to maintain a negative pressure environment, and simultaneously adding lime nitrogen powder into the thiourea synthesis kettle through a lime nitrogen powder pipeline by a lime nitrogen storage tank, wherein the lime nitrogen powder is mixed with water; the gas-liquid mixture absorbed by the water ring vacuum pump is separated by a gas-liquid separator, the liquid is introduced into a thiourea mother liquor collecting tank, and the gas enters a tail gas treatment device for treatment;
(3) Introducing hydrogen sulfide into the thiourea synthesis kettle through a hydrogen sulfide pipeline for reaction;
(4) Lime nitrogen is added again, and the lime nitrogen storage tank is used for adding lime nitrogen powder again into the thiourea synthesis kettle through a lime nitrogen powder pipeline for continuous reaction to obtain a solid-liquid mixture;
in the steps (2) - (4), continuously maintaining a negative pressure condition in the thiourea synthesis kettle for reaction;
(5) Filtering, namely filtering the solid-liquid mixture by a filtering device, and introducing filtrate into a cooling crystallization device;
(6) Cooling crystallization is carried out, and the filtrate is cooled and crystallized by a cooling crystallization device, so that thiourea crystals are separated out;
(7) Centrifugally separating and drying, namely introducing filtrate containing thiourea crystals into a centrifugal device, centrifugally separating the filtrate into thiourea crystals and thiourea mother liquor, introducing the thiourea mother liquor into a thiourea mother liquor tank, and collecting and drying the thiourea crystals to obtain a thiourea product;
(8) Recycling thiourea mother liquor, and using a small part of thiourea mother liquor in a thiourea mother liquor tank as working solution of a water ring vacuum pump; introducing residual thiourea mother liquor into a thiourea mother liquor collecting tank, and then introducing the thiourea mother liquor into a thiourea synthesizing kettle through a second liquid inlet to serve as reaction liquid for the subsequent thiourea synthesizing process;
repeating the steps (2) - (8) to realize continuous preparation of thiourea.
Further, in the steps (2) - (4), the air pressure in the thiourea synthesis kettle is kept at-20 kpa to-80 kpa.
Further, the reaction temperature in the step (3) is 50-100 ℃ and the reaction time is 30-120 min.
Further, the reaction temperature in the step (4) is 60-120 ℃ and the reaction time is 90-240 min.
Further, in the step (5), the temperature of the filtrate is reduced to 7-15 ℃.
Further, in the step (7), the impurity content of the thiourea mother liquor is 1wt.% to 3wt.%, and the impurities include calcium hydrosulfide, calcium hydroxide and other unavoidable impurities.
Further, the method also comprises the step (9): when the thiourea mother liquor in the thiourea mother liquor collecting tank is insufficient as the reaction liquid in the thiourea synthesizing kettle, a water adding pipeline is started to supplement water into the thiourea synthesizing kettle.
The invention has the beneficial effects that:
1. According to the invention, the low Wen Liuniao mother solution is used as the working solution of the water ring vacuum pump, on one hand, the low temperature of the thiourea mother solution is fully utilized, the temperature of the reaction solution of the water ring vacuum pump is low, the efficiency of maintaining negative pressure is improved, and the energy consumption is reduced; on the other hand, the working fluid passing through the water ring vacuum pump is not required to be cooled, and the running cost of the system is further reduced.
2. According to the invention, the working solution flowing through the water ring vacuum pump is directly introduced into the thiourea mother liquor collecting tank to serve as the reaction solution for the subsequent thiourea synthesis reaction, the working solution mixed with the gas phase medium is not directly returned to the water ring vacuum pump for circulation, and impurities such as ammonia, hydrogen sulfide, calcium hydrosulfide, lime nitrogen dust and the like are not enriched in the working solution, so that the service life of the water ring vacuum pump can be prolonged.
3. According to the invention, the thiourea mother liquor obtained by ending the thiourea synthesis reaction and separating the thiourea crystal is used as the reaction liquid to be reused in the thiourea synthesis reaction, so that the available components in the thiourea mother liquor, such as thiourea, calcium hydroxide, calcium hydrosulfide and the like, can be fully recycled, the utilization rate of resources is improved, the consumption of raw materials is reduced, and meanwhile, the thiourea synthesis reaction can be promoted, and the production efficiency is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic structural view of embodiment 1 of the present invention.
In the figure, a 1-thiourea mother liquor tank, a 2-water ring vacuum pump, a 3-gas-liquid separator, a 4-thiourea mother liquor collecting tank, a 5-thiourea synthesizing tank, a 6-filtering device, a 7-cooling crystallization device, an 8-centrifuging device, a 9-water adding pipeline, a 10-lime nitrogen storage tank, a 11-lime nitrogen powder pipeline, a 12-hydrogen sulfide pipeline, a 13-tail gas treatment device and a 14-water supplementing pipeline.
Detailed Description
In order to make the technical solution of the present invention better understood by those skilled in the art, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
Example 1
The thiourea synthesis system comprises a thiourea synthesis kettle 5, wherein a stirring device is arranged in the thiourea synthesis kettle 5, a first liquid inlet, a second liquid inlet, an air inlet and a powder feed inlet are arranged on the thiourea synthesis kettle 5, a discharge port is arranged at the bottom of the thiourea synthesis kettle 5, and a negative pressure air outlet is arranged at the top of the thiourea synthesis kettle 5; the first liquid inlet is connected with a water adding pipeline 9, the air inlet is connected with a hydrogen sulfide pipeline 12, the powder material inlet is connected with a lime nitrogen storage tank 10 through a lime nitrogen powder material pipeline, and the discharge port is sequentially connected with a filtering device 6, a cooling crystallization device 7 and a centrifugal device 8; the filtering device 6 comprises a coarse filter and a fine filter which are connected in sequence, wherein the filtering precision of the coarse filter is 15 mu m, and the filtering precision of the fine filter is 0.5 mu m; the liquid outlet of the centrifugal device 8 is connected with a thiourea mother liquid tank 1, the thiourea mother liquid tank 1 is connected with a thiourea mother liquid collecting tank 4, and the thiourea mother liquid collecting tank 4 is connected with a second liquid inlet; the thiourea mother liquor tank 1 is connected with a water supplementing pipeline 14; still include water ring vacuum pump 2, be provided with negative pressure air inlet, working solution inlet and mixed export on the water ring vacuum pump 2, negative pressure air inlet is connected with the negative pressure gas outlet, and the working solution inlet is connected with thiourea mother liquor jar 1, and mixed export is connected with gas-liquid separator 3, and gas-liquid separator 3's gas outlet is connected with tail gas processing apparatus 13, and gas-liquid separator 3's liquid outlet is connected with thiourea mother liquor collecting vat 4.
Example 2
A method of performing thiourea synthesis using the thiourea synthesis system of example 1, the steps comprising:
(1) The water adding pipeline 9 adds water into the thiourea synthesis kettle 5, and the water supplementing pipeline 14 adds water into the thiourea mother liquid tank 1;
(2) Starting a water ring vacuum pump 2 to keep a negative pressure environment in the thiourea synthesis kettle 5, and simultaneously adding lime nitrogen powder into the thiourea synthesis kettle 5 through a lime nitrogen powder pipeline 11 by a lime nitrogen storage tank 10, wherein the lime nitrogen powder is mixed with water; the gas-liquid mixture absorbed by the water ring vacuum pump 2 is separated by the gas-liquid separator 3, the liquid is introduced into the thiourea mother liquor collecting tank 4, and the gas enters the tail gas treatment device 13 for treatment;
(3) The hydrogen sulfide pipeline 12 is used for introducing hydrogen sulfide into the thiourea synthesis kettle 5 for reaction, wherein the reaction temperature is 50 ℃, and the reaction time is 30min;
(4) Lime nitrogen powder is added into the thiourea synthesis kettle 5 again through a lime nitrogen powder pipeline 11 by the lime nitrogen storage tank 10 for continuous reaction at the reaction temperature of 60 ℃ for 90min to obtain a solid-liquid mixture;
in the steps (2) - (4), the thiourea synthesis kettle 5 is continuously kept under the negative pressure condition for reaction, and the air pressure is kept at-20 kpa;
(5) Filtering the solid-liquid mixture by a filtering device 6, and introducing the filtrate into a cooling crystallization device 7;
(6) The cooling crystallization device 7 is used for cooling and crystallizing the filtrate, and cooling to 7 ℃ to precipitate thiourea crystals;
(7) Introducing filtrate containing thiourea crystals into a centrifugal device 8, centrifugally separating the filtrate into thiourea crystals and thiourea mother liquor, introducing the thiourea mother liquor into a thiourea mother liquor tank 1, wherein the impurity content of the thiourea mother liquor is 2.35wt.%, and the impurities comprise calcium hydrosulfide, calcium hydroxide and other unavoidable impurities; collecting and drying thiourea crystals to obtain thiourea products;
(8) Part of thiourea mother liquor in the thiourea mother liquor tank 1 is used as working solution of a water ring vacuum pump 2; the residual thiourea mother liquor is introduced into a thiourea mother liquor collecting tank 4 and then is introduced into a thiourea synthesizing kettle 5 through a second liquid inlet to be used as a reaction solution for the subsequent thiourea synthesizing process;
Repeating the steps (2) - (8);
(9) When the thiourea mother liquor in the thiourea mother liquor collecting tank 4 is insufficient as the reaction liquid in the thiourea synthesizing tank 5, the water-adding pipe 9 is opened to replenish water into the thiourea synthesizing tank 5.
Example 3
A method of performing thiourea synthesis using the thiourea synthesis system of example 1, the steps comprising:
(1) The water adding pipeline 9 adds water into the thiourea synthesis kettle 5, and the water supplementing pipeline 14 adds water into the thiourea mother liquid tank 1;
(2) Starting a water ring vacuum pump 2 to keep a negative pressure environment in the thiourea synthesis kettle 5, and simultaneously adding lime nitrogen powder into the thiourea synthesis kettle 5 through a lime nitrogen powder pipeline 11 by a lime nitrogen storage tank 10, wherein the lime nitrogen powder is mixed with water; the gas-liquid mixture absorbed by the water ring vacuum pump 2 is separated by the gas-liquid separator 3, the liquid is introduced into the thiourea mother liquor collecting tank 4, and the gas enters the tail gas treatment device 13 for treatment;
(3) The hydrogen sulfide pipeline 12 is used for introducing hydrogen sulfide into the thiourea synthesis kettle 5 for reaction, wherein the reaction temperature is 100 ℃, and the reaction time is 120min;
(4) Lime nitrogen powder is added into the thiourea synthesis kettle 5 again through a lime nitrogen powder pipeline 11 by the lime nitrogen storage tank 10 for continuous reaction at the reaction temperature of 120 ℃ for 240min to obtain a solid-liquid mixture;
in the steps (2) - (4), the thiourea synthesis kettle 5 is continuously kept under the negative pressure condition for reaction, and the air pressure is kept at-80 kpa;
(5) Filtering the solid-liquid mixture by a filtering device 6, and introducing the filtrate into a cooling crystallization device 7;
(6) The cooling crystallization device 7 is used for cooling and crystallizing the filtrate, cooling to 15 ℃ and separating out thiourea crystals;
(7) Introducing filtrate containing thiourea crystals into a centrifugal device 8, centrifugally separating the filtrate into thiourea crystals and thiourea mother liquor, introducing the thiourea mother liquor into a thiourea mother liquor tank 1, wherein the impurity content of the thiourea mother liquor is 1.21wt.%, and the impurities comprise calcium hydrosulfide, calcium hydroxide and other unavoidable impurities; collecting and drying thiourea crystals to obtain thiourea products;
(8) Part of thiourea mother liquor in the thiourea mother liquor tank 1 is used as working solution of a water ring vacuum pump 2; the residual thiourea mother liquor is introduced into a thiourea mother liquor collecting tank 4 and then is introduced into a thiourea synthesizing kettle 5 through a second liquid inlet to be used as a reaction solution for the subsequent thiourea synthesizing process;
Repeating the steps (2) - (8);
(9) When the thiourea mother liquor in the thiourea mother liquor collecting tank 4 is insufficient as the reaction liquid in the thiourea synthesizing tank 5, the water-adding pipe 9 is opened to replenish water into the thiourea synthesizing tank 5.
Example 4
A method of performing thiourea synthesis using the thiourea synthesis system of example 1, the steps comprising:
(1) The water adding pipeline 9 adds water into the thiourea synthesis kettle 5, and the water supplementing pipeline 14 adds water into the thiourea mother liquid tank 1;
(2) Starting a water ring vacuum pump 2 to keep a negative pressure environment in the thiourea synthesis kettle 5, and simultaneously adding lime nitrogen powder into the thiourea synthesis kettle 5 through a lime nitrogen powder pipeline 11 by a lime nitrogen storage tank 10, wherein the lime nitrogen powder is mixed with water; the gas-liquid mixture absorbed by the water ring vacuum pump 2 is separated by the gas-liquid separator 3, the liquid is introduced into the thiourea mother liquor collecting tank 4, and the gas enters the tail gas treatment device 13 for treatment;
(3) The hydrogen sulfide pipeline 12 is used for introducing hydrogen sulfide into the thiourea synthesis kettle 5 for reaction, wherein the reaction temperature is 70 ℃, and the reaction time is 90min;
(4) Lime nitrogen powder is added into the thiourea synthesis kettle 5 again through a lime nitrogen powder pipeline 11 by the lime nitrogen storage tank 10 for continuous reaction at the reaction temperature of 100 ℃ for 150min to obtain a solid-liquid mixture;
in the steps (2) - (4), the thiourea synthesis kettle 5 is continuously kept under the negative pressure condition for reaction, and the air pressure is kept at-50 kpa;
(5) Filtering the solid-liquid mixture by a filtering device 6, and introducing the filtrate into a cooling crystallization device 7;
(6) The cooling crystallization device 7 is used for cooling and crystallizing the filtrate to 10 ℃ to precipitate thiourea crystals;
(7) Introducing filtrate containing thiourea crystals into a centrifugal device 8, centrifugally separating the filtrate into thiourea crystals and thiourea mother liquor, introducing the thiourea mother liquor into a thiourea mother liquor tank 1, wherein the impurity content of the thiourea mother liquor is 1.45wt.%, and the impurities comprise calcium hydrosulfide, calcium hydroxide and other unavoidable impurities; collecting and drying thiourea crystals to obtain thiourea products;
(8) Part of thiourea mother liquor in the thiourea mother liquor tank 1 is used as working solution of a water ring vacuum pump 2; the residual thiourea mother liquor is introduced into a thiourea mother liquor collecting tank 4 and then is introduced into a thiourea synthesizing kettle 5 through a second liquid inlet to be used as a reaction solution for the subsequent thiourea synthesizing process;
Repeating the steps (2) - (8);
(9) When the thiourea mother liquor in the thiourea mother liquor collecting tank 4 is insufficient as the reaction liquid in the thiourea synthesizing tank 5, the water-adding pipe 9 is opened to replenish water into the thiourea synthesizing tank 5.
Although the present invention has been described in detail by way of preferred embodiments with reference to the accompanying drawings, the present invention is not limited thereto. Various equivalent modifications and substitutions may be made in the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and it is intended that all such modifications and substitutions be within the scope of the present invention/be within the scope of the present invention as defined by the appended claims.
Claims (10)
1. The thiourea synthesis system comprises a thiourea synthesis kettle, and is characterized in that a first liquid inlet, a second liquid inlet, an air inlet and a powder feed inlet are formed in the thiourea synthesis kettle, a discharge port is formed in the bottom of the thiourea synthesis kettle, and a negative pressure air outlet is formed in the top of the thiourea synthesis kettle; the first liquid inlet is connected with a water adding pipeline, the air inlet is connected with a hydrogen sulfide pipeline, the powder inlet is connected with a lime nitrogen storage tank through a lime nitrogen powder pipeline, and the discharge port is sequentially connected with a filtering device, a cooling crystallization device and a centrifugal device; the liquid outlet of the centrifugal device is connected with a thiourea mother liquor tank, the thiourea mother liquor tank is connected with a thiourea mother liquor collecting tank, and the thiourea mother liquor collecting tank is connected with a second liquid inlet; the thiourea mother liquid tank is connected with a water supplementing pipeline; still include the water ring vacuum pump, be provided with negative pressure air inlet, working solution inlet and mixed export on the water ring vacuum pump, negative pressure air inlet is connected with the negative pressure gas outlet, and the working solution inlet is connected with thiourea mother liquor jar, and mixed export is connected with gas-liquid separator, and gas outlet and the tail gas processing apparatus of gas-liquid separator are connected, and gas-liquid separator's liquid outlet is connected with thiourea mother liquor collecting vat.
2. The thiourea synthesis system of claim 1, wherein a stirring device is provided in the thiourea synthesis tank.
3. The thiourea synthesis system of claim 1, wherein the filter device comprises a coarse filter and a fine filter connected in sequence, the filter accuracy of the coarse filter is 15-30 μm, and the filter accuracy of the fine filter is 0.5-10 μm.
4. A method of preparing thiourea using the thiourea synthesis system of claim 1, characterized in that the steps comprise:
(1) The water adding pipeline adds water into the thiourea synthesis kettle, and the water supplementing pipeline adds water into the thiourea mother liquid tank;
(2) Starting a water ring vacuum pump to enable the thiourea synthesis kettle to keep a negative pressure environment, and simultaneously adding lime nitrogen powder into the thiourea synthesis kettle through a lime nitrogen powder pipeline by a lime nitrogen storage tank, wherein the lime nitrogen powder is mixed with water; the gas-liquid mixture absorbed by the water ring vacuum pump is separated by a gas-liquid separator, the liquid is introduced into a thiourea mother liquor collecting tank, and the gas enters a tail gas treatment device for treatment;
(3) Introducing hydrogen sulfide into the thiourea synthesis kettle through a hydrogen sulfide pipeline for reaction;
(4) Adding lime nitrogen powder again into the thiourea synthesis kettle through a lime nitrogen powder pipeline by the lime nitrogen storage tank for continuous reaction to obtain a solid-liquid mixture;
in the steps (2) - (4), continuously maintaining a negative pressure condition in the thiourea synthesis kettle for reaction;
(5) Filtering the solid-liquid mixture by a filtering device, and introducing filtrate into a cooling crystallization device;
(6) The cooling crystallization device is used for cooling and crystallizing the filtrate to separate out thiourea crystals;
(7) Introducing filtrate containing thiourea crystals into a centrifugal device, centrifugally separating the filtrate into thiourea crystals and thiourea mother liquor, introducing the thiourea mother liquor into a thiourea mother liquor tank, and collecting and drying the thiourea crystals to obtain a thiourea product;
(8) Using part of thiourea mother liquor in a thiourea mother liquor tank as working solution of a water ring vacuum pump; introducing residual thiourea mother liquor into a thiourea mother liquor collecting tank, and then introducing the thiourea mother liquor into a thiourea synthesizing kettle through a second liquid inlet to serve as reaction liquid for the subsequent thiourea synthesizing process;
Repeating the steps (2) - (8).
5. The method according to claim 4, wherein in the steps (2) to (4), the air pressure in the thiourea synthesis kettle is kept at-20 kpa to-80 kpa.
6. The method of claim 4, wherein the reaction temperature in the step (3) is 50-100 ℃ and the reaction time is 30-120 min.
7. The method of claim 4, wherein the reaction temperature in step (4) is 60-120 ℃ and the reaction time is 90-240 min.
8. The method of claim 4, wherein the step (5) is to cool the filtrate to 7-15 ℃.
9. The method of claim 4, wherein the thiourea mother liquor in step (7) has an impurity content of 1wt.% to 3wt.%, and the impurities include calcium hydrosulfide, calcium hydroxide and other unavoidable impurities.
10. The method of claim 4, further comprising the step (9) of: when the thiourea mother liquor in the thiourea mother liquor collecting tank is insufficient as the reaction liquid in the thiourea synthesizing kettle, a water adding pipeline is started to supplement water into the thiourea synthesizing kettle.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB640976A (en) * | 1947-04-02 | 1950-08-02 | Saint Gobain | Improvements in the manufacture of thiourea |
| CN102731356A (en) * | 2011-04-15 | 2012-10-17 | 中国石油化工股份有限公司 | Thiourea cleaning production method |
| CN102875434A (en) * | 2012-10-25 | 2013-01-16 | 黄河三角洲京博化工研究院有限公司 | Method for synthesizing thiocarbamide at low temperature |
| CN218451884U (en) * | 2022-08-31 | 2023-02-07 | 宁夏新锐生物科技有限公司 | Thiourea-based propionic acid crystallization system |
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- 2024-04-18 CN CN202410466688.6A patent/CN118079823B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB640976A (en) * | 1947-04-02 | 1950-08-02 | Saint Gobain | Improvements in the manufacture of thiourea |
| CN102731356A (en) * | 2011-04-15 | 2012-10-17 | 中国石油化工股份有限公司 | Thiourea cleaning production method |
| CN102875434A (en) * | 2012-10-25 | 2013-01-16 | 黄河三角洲京博化工研究院有限公司 | Method for synthesizing thiocarbamide at low temperature |
| CN218451884U (en) * | 2022-08-31 | 2023-02-07 | 宁夏新锐生物科技有限公司 | Thiourea-based propionic acid crystallization system |
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