CN117143303A - Production process method of paraformaldehyde - Google Patents
Production process method of paraformaldehyde Download PDFInfo
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- CN117143303A CN117143303A CN202311035001.5A CN202311035001A CN117143303A CN 117143303 A CN117143303 A CN 117143303A CN 202311035001 A CN202311035001 A CN 202311035001A CN 117143303 A CN117143303 A CN 117143303A
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- 229930040373 Paraformaldehyde Natural products 0.000 title claims abstract description 74
- 229920002866 paraformaldehyde Polymers 0.000 title claims abstract description 74
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 20
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 100
- 238000001035 drying Methods 0.000 claims abstract description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 33
- 238000009835 boiling Methods 0.000 claims abstract description 22
- 238000005469 granulation Methods 0.000 claims abstract description 14
- 230000003179 granulation Effects 0.000 claims abstract description 14
- 239000007864 aqueous solution Substances 0.000 claims abstract description 13
- 239000008098 formaldehyde solution Substances 0.000 claims abstract description 13
- 238000004806 packaging method and process Methods 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 239000007789 gas Substances 0.000 claims description 9
- 239000002994 raw material Substances 0.000 claims description 9
- 238000010521 absorption reaction Methods 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 8
- 238000012216 screening Methods 0.000 claims description 7
- 238000001704 evaporation Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 5
- AVXURJPOCDRRFD-UHFFFAOYSA-N Hydroxylamine Chemical compound ON AVXURJPOCDRRFD-UHFFFAOYSA-N 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- 239000011552 falling film Substances 0.000 claims description 4
- 238000007738 vacuum evaporation Methods 0.000 claims description 4
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 2
- 239000002245 particle Substances 0.000 abstract description 12
- 239000007787 solid Substances 0.000 abstract description 9
- 239000010419 fine particle Substances 0.000 abstract description 7
- 238000003860 storage Methods 0.000 abstract description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 239000000243 solution Substances 0.000 description 14
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 239000012086 standard solution Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000002808 molecular sieve Substances 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 3
- 229940001482 sodium sulfite Drugs 0.000 description 3
- 235000010265 sodium sulphite Nutrition 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- CKFGINPQOCXMAZ-UHFFFAOYSA-N methanediol Chemical compound OCO CKFGINPQOCXMAZ-UHFFFAOYSA-N 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- DHKHKXVYLBGOIT-UHFFFAOYSA-N acetaldehyde Diethyl Acetal Natural products CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 description 1
- 125000002777 acetyl group Chemical class [H]C([H])([H])C(*)=O 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229940101006 anhydrous sodium sulfite Drugs 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- 239000003899 bactericide agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 238000007265 chloromethylation reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 239000000645 desinfectant Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000010813 internal standard method Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
- C08G2/08—Polymerisation of formaldehyde
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a production process method of paraformaldehyde, which belongs to the technical field of paraformaldehyde production, and the production method of paraformaldehyde disclosed by the invention comprises the steps of enabling concentrated formaldehyde aqueous solution to be in contact with fine-grained paraformaldehyde serving as seeds in a boiling granulator, and enabling solid particles to float in the air to form a boiling state, so that good contact is obtained between gas and solid; the formaldehyde solution deposits the film on the solid particle surface, water in the film is evaporated, the paraformaldehyde is heated, polymerized and solidified on the particle surface, the granularity is continuously increased, then the screened fine paraformaldehyde still participates in continuous boiling granulation as seed fine particles, the large-particle paraformaldehyde is sent to a packaging system, the performances of difficult caking and the like are achieved, the storage and the transportation are facilitated, the product quality is high, the product quality is stable, the automation level is high, the production efficiency is high, the drying time is short, the particle size of the prepared paraformaldehyde is adjustable, the operation is flexible, and the prepared paraformaldehyde has good fluidity, solubility and dispersibility.
Description
Technical Field
The invention belongs to the technical field of paraformaldehyde production, and particularly relates to a production process method of paraformaldehyde.
Background
Paraformaldehyde is a high molecular polymer, namely, a linear polymer which is aliased polymerized formaldehyde and solid formaldehyde, has a molecular formula of HO (CH 2O) nH, is white or colorless combustible crystalline powder or granular or flaky solid, has formaldehyde smell and is formaldehyde. Has no fixed melting point, and is decomposed by heating. The melting point is 120-170 ℃. Is easily soluble in hot water and emits formaldehyde, slowly soluble in cold water, soluble in caustic alkali and alkali carbonate solutions, insoluble in alcohol and ether, and highly insoluble in water. Formaldehyde-like reactions, such as chloromethylation, acetal formation with alcohols, and the like, can occur. Is used for synthetic resin, adhesive, medicine, bactericide, pesticide, disinfectant, etc. The paraformaldehyde powder generally refers to a solid formaldehyde product with low polymerization degree, is a powder with the content of more than or equal to 95% and is a granular or powdery product with the content of 91% -93%, and is convenient to store and transport. Paraformaldehyde is generally prepared from industrial formaldehyde by vacuum concentration, polymerization, dehydration, drying and other procedures. The selection of the manufacturing process and the control of the operation conditions influence the molecular weight and various index performances of the paraformaldehyde, particularly the water solubility, the depolymerization is carried out in the water dissolution process of the paraformaldehyde, so that formaldehyde hydrate with lower molecular weight is depolymerized, the good water solubility means good dissociation property, the paraformaldehyde with good water solubility is easy to release formaldehyde when being decomposed by heat, and the reaction using the paraformaldehyde as a raw material usually takes part in the reaction directly, so that the good water solubility means high reaction activity. Therefore, many industries using paraformaldehyde desire paraformaldehyde products with good water solubility. After 2006, the chinese paraformaldehyde industry has entered a fast-growing period, the technical level gradually overtakes foreign enterprises, the productivity has been rapidly expanded, and by 2011, the chinese paraformaldehyde productivity has broken through 50 ten thousand tons, accounting for more than half of the global total productivity. Vacuum rake drying method: haroldF. Research reports that a stirring paddle dryer is adopted to adjust a certain vacuum degree to prepare paraformaldehyde, the aldehyde content can reach 95%, and a traditional PF process route for preparing PF by vacuum rake drying is developed, wherein the process comprises formaldehyde vacuum concentration, formaldehyde polymerization, rake drying, screening, crushing and packaging. The process has the advantages of vacuum drying and stirring drying, and has the advantages of energy saving, high efficiency, low investment, less dust and no loss of a large amount of aldehyde. Disadvantages: dead corners exist, discharging is troublesome, product lumps are difficult to crush, the production period is long, the traditional old production process is basically eliminated abroad, and only a few factories and families only produce paraformaldehyde by the method at present. Those skilled in the art are urgent to develop a process for producing paraformaldehyde to meet the existing application market and performance requirements.
Disclosure of Invention
In view of the above, the present invention provides a process for producing paraformaldehyde.
A method for producing paraformaldehyde, comprising the following steps:
step one, raw material preparation: in a primary dryer, evaporating and concentrating formaldehyde aqueous solution with the mass concentration of 45-50% at the temperature of 45-48 ℃ until the formaldehyde weight concentration is 70-82%, preheating in an evaporator, then, performing vacuum evaporation and concentration in a flash evaporation separator, pumping into a secondary dryer after concentrating to 73-75%, and concentrating to 80-85% in a falling film evaporator; step two, boiling granulation: the concentrated formaldehyde solution after being concentrated to 80 to 85 percent is sent into a boiling granulator, and fine grain paraformaldehyde accounting for 5 to 10 percent of the mass ratio of the concentrated formaldehyde solution is continuously introduced into the granulator for continuous granulation; thirdly, drying after granulating to obtain paraformaldehyde with the concentration of 92% -96%, conveying the paraformaldehyde to a vibrating screen for screening through inert nitrogen flow, conveying the paraformaldehyde to a packaging system after screening, and packaging the paraformaldehyde.
Further, the second-step boiling granulator sprays feed liquid at the surface temperature of an internal heater of 50-60 ℃ according to the air inlet temperature of 50-60 ℃ and the bed temperature of 40-45 ℃ according to the area of 0.66-0.73 m per square bed 3 And/h, the pressure of the compressed gas is 0.25-0.3 MPa, and the environment is 20-25 ℃.
Further, triethanolamine or hydroxylamine with a mass content of 0.5 to 1% is added to the raw material of the formaldehyde aqueous solution with a mass concentration of 45 to 50% at a temperature of 45 to 48 ℃.
Furthermore, the formaldehyde and water vapor mixture extracted from the tops of the primary dryer and the secondary dryer in the first step is sent into an absorption tower, and water is used as absorption liquid.
Further, the drying in the third step is divided into primary drying or primary drying and secondary drying of a belt dryer, wherein the primary drying heating temperature is 60-65 ℃, the discharging temperature is 40-45 ℃, the secondary drying heating temperature is 80-90 ℃, and the discharging temperature is 50-55 ℃.
Further, the heating medium of the belt dryer is water or steam, the laying thickness is 2.5-4 mm, the vacuum degree is-97 to-90 kPa, the conveyor belt speed is 0.1-0.15 m/min, the number of drying layers is 3-5, the effective drying section is 8-10 m, and the net bandwidth is 1.2-2 m.
The invention has the beneficial effects that:
the invention discloses a method for producing paraformaldehyde, which comprises the steps of putting concentrated formaldehyde aqueous solution into a boiling granulator to be contacted with fine paraformaldehyde serving as seeds, and floating solid particles in the air to form a boiling state, so that good contact between gas and solid is obtained. The formaldehyde solution deposits a film on the surface of solid particles, water in the film is evaporated, paraformaldehyde is solidified on the surface of the particles, and the granularity is continuously increased. The larger particles fall downward and are again blown upward. And (3) circulating until the granularity reaches the requirement, screening, wherein the screened fine-particle paraformaldehyde still serves as seed fine particles to participate in continuous boiling granulation, and conveying the large-particle paraformaldehyde to a packaging system to package the paraformaldehyde. The granular paraformaldehyde produced by the boiling granulation technology has the performances of difficult caking and the like, is favorable for storage and transportation, has high product quality and lower production cost.
Compared with the prior art, the invention has the following advantages:
in the past, the harrow type air harrow type drying method is used for producing paraformaldehyde, the product blocks are difficult to crush, the production period is long, the energy consumption is high, the cost is high, the product quality is poor, and the scale is not easy to go. In daily production practice, it is found that in the boiling granulator, part of paraformaldehyde fine particles are introduced and used as seeds for granulation, the paraformaldehyde fine particles are contacted with formaldehyde concentrated solution, so that the production efficiency is high, the reaction speed can be improved, the product quality is stable, the automation level is high, the production efficiency is high, the drying time is short, the prepared paraformaldehyde is adjustable in particle size, flexible in operation, good in fluidity, solubility and dispersibility, the production cost and efficiency, and the equipment cost and energy consumption are greatly reduced.
Detailed Description
Example 1
Industrial formaldehyde, fan Qun drying equipment factory belt dryer, anhui Ruibu New Material Co., ltd; a diurnal FLZN1200 boiling granulator;
step one, raw material preparation: further, triethanolamine and hydroxylamine with the mass content of 1% are added into the raw material of the formaldehyde aqueous solution with the mass concentration of 50% at the temperature of 48 ℃, the industrial formaldehyde aqueous solution with the mass concentration of 50% at the temperature of 48 ℃ is evaporated and concentrated to the weight concentration of formaldehyde of 82% in a primary dryer, the formaldehyde aqueous solution enters an evaporator for preheating, enters a flash evaporation separator for vacuum evaporation and concentration, is pumped into a secondary dryer after being concentrated to 73% -75%, is concentrated to 85% in a falling film evaporator, and is sent into an absorption tower by a formaldehyde and water vapor mixer which is pumped out from the tops of the primary dryer and the secondary dryer, and water is adopted as absorption liquid; step two, boiling granulation: concentrating to 85%, feeding into a boiling granulator, continuously introducing 0.4mm fine particle paraformaldehyde accounting for 10% of the concentrated formaldehyde solution in the granulator, wherein the boiling granulator is used for spraying 0.66m of formaldehyde solution per square of bed area according to the air inlet temperature of 50 ℃, the surface temperature of an internal heater of 50 ℃, and the bed temperature of 40% 3 And (3) carrying out continuous granulation under the condition that the pressure of compressed gas is 0.25MPa and the environment is 20 ℃; and thirdly, drying after granulation, namely, drying the mixture into primary drying and then secondary drying, wherein the primary drying heating temperature is 65 ℃, the discharging temperature is 45 ℃, the secondary drying heating temperature is 80-90 ℃, the discharging temperature is 55 ℃, the paraformaldehyde with the concentration of 96% is obtained, the paraformaldehyde is conveyed to a vibrating screen through inert nitrogen flow to be screened, the screened paraformaldehyde is conveyed to a packaging system, the paraformaldehyde is packaged, the heating medium of the belt type dryer is water or steam, the laying thickness is 2.5mm, the vacuum degree is-97 kPa, the conveyor belt speed is 0.1m/min, the number of drying layers is 3, the effective drying section is 8m, and the network bandwidth is 1.2m.
Average 15 days product performance on production line: 96.48% formaldehyde, 0.000% acid value, 7.4 pH (90 parts water+10 parts paraformaldehyde), 0.02854% ash, 0.00013% iron; bulk density of 0.6-0.8Kg/L, true particle density of 1.4Kg/L0.6mm
The product batch performance was tested following the procedure of example 1, followed by 15 days of sampling, and the results are shown in Table 1.
Table 1 example 1 multi-batch test performance results for paraformaldehyde products
Example 2
Industrial formaldehyde, fan Qun drying equipment factory belt dryer, anhui Ruibu New Material Co., ltd; a diurnal FLZN1200 boiling granulator;
step one, raw material preparation: further, hydroxylamine with the mass content of 0.5% is added into the raw material of the formaldehyde aqueous solution with the mass concentration of 45% at the temperature of 45 ℃, the industrial formaldehyde aqueous solution with the mass concentration of 45% at the temperature of 45 ℃ is evaporated and concentrated to 70% of formaldehyde weight concentration in a primary dryer, the formaldehyde aqueous solution enters an evaporator for preheating, enters a flash evaporation separator for vacuum evaporation and concentration, is pumped into a secondary dryer after being concentrated to 73%, is concentrated to 80% in a falling film evaporator, and is sent into an absorption tower by adopting water as absorption liquid by a formaldehyde and water vapor mixer which is pumped out from the tops of the primary dryer and the secondary dryer; step two, boiling granulation: concentrating to 80%, feeding into a boiling granulator, continuously introducing 0.4mm fine particle paraformaldehyde accounting for 5% of the concentrated formaldehyde solution in the granulator, wherein the boiling granulator is used for spraying 0.73m of formaldehyde solution per square of bed area according to the air inlet temperature of 60 ℃ and the surface temperature of an internal heater of 60 ℃ and the bed temperature of 45% 3 And (3) carrying out continuous granulation under the condition that the pressure of compressed gas is 0.3MPa and the environment is 25 ℃; step three, drying after granulation, including primary drying, wherein the primary drying heating temperature is 65 ℃ and the discharging temperature is 45 ℃, so as to obtain paraformaldehyde with 92% concentration, conveying the paraformaldehyde to a vibrating screen for screening through inert nitrogen flow, conveying the screened paraformaldehyde to a packaging system, packaging the paraformaldehyde, and obtaining the productThe heating medium of the belt dryer is water or steam, the laying thickness is 4mm, the vacuum is-90 kPa, the conveyor belt speed is 0.15m/min, the number of drying layers is 5, the effective drying section is 10m, and the mesh bandwidth is 2m.
Average product performance on 10 days of production line: 92.59% formaldehyde, 0.001% acid value, 6.2% pH (90 parts water+10 parts paraformaldehyde), 0.0013% ash, 0.0001% iron;
the product batch performance was tested following the procedure of example 2, followed by 15 days of sampling, and the results are shown in Table 2.
Table 2 example 2 multi-batch test performance data for paraformaldehyde products
Note that: the detection method comprises the following steps: the reagent and water used in the standard are three-stage water conforming to GB/T6682. Standard solution preparations and products used in the standard are prepared according to GB/T601, GB/T602 and GB/T603. The appearance was visually observed under natural light. Determination of formaldehyde content: the paraformaldehyde reacts with an excess of neutral sodium sulfite solution to form sodium hydroxide, which is titrated with sulfuric acid standard solution using a potentiometric titrator. Reagent and solution sodium sulfite solution: c (Na) 2 SO 3 ) 126g/L of anhydrous sodium sulfite was weighed, dissolved in water, diluted to 1L, adjusted to pH 9.3 with 1.0mol/L sulfuric acid, and shaken well for use. The solution has a period of one week. Sulfuric acid standard solution: c (1/2H) 2 SO 4 ) =1.0 mol/L. An automatic titrator for instrument potential. Analytical procedure 0.5g of sample was weighed incrementally in a 100mL titration cup to the nearest 0.0001g, 40mL of sodium sulfite solution was added, titrated to endpoint on a potentiometric auto-titrator with sulfuric acid standard solution, and the analytical results were read directly from the auto-titrator. The arithmetic average of the two replicates was taken as the measurement. The difference between the two replicates was not more than 0.7%. Principle of acidity measurementThe aqueous aldehyde solution is heated to depolymerize to formaldehyde solution, and the formic acid in the sample is neutralized with standard sodium hydroxide solution. Reagent and solution sodium hydroxide solution: c (NaOH) =0.01 mol/L. Potentiometric automatic titrator. 10g of the sample is weighed into a 250mL beaker, the sample is accurate to 0.0001g, 90mL of tertiary water is added, the sample is slowly heated on a stirring heating electric furnace, the sample is cooled to room temperature after the solution is completely dissolved, and the sample is titrated to an end point on a potentiometric automatic titrator by using a sodium hydroxide standard solution. The arithmetic average of the two replicates was taken as the measurement. The pH value of the aqueous solution is measured after heating, depolymerizing and cooling the aqueous solution. In the measurement step, 10g of paraformaldehyde sample and 90g of tertiary water are added into an abrasive flask, the upper opening of the abrasive flask is connected with a condenser pipe, the mixture is depolymerized and clear in a water bath at 90 ℃, and then the mixture is placed at room temperature for cooling, and the pH value of the solution is measured. The iron content was measured as specified in GB/T3049. 5.0g (to the nearest 0.01 g) of paraformaldehyde sample was weighed, added with 30mL of water, dissolved by heating, transferred to a 100mL volumetric flask, and the other steps were performed as specified in GB/T3049. Ash content measuring instrument muffle furnace (1200 ℃). Analysis procedure 10g of the sample were carefully weighed into a dried platinum crucible (mass m 1), burned at 600 c, the residue was placed in a desiccator for cooling and weighing (m 2). The percentage content of ash X is calculated, and the arithmetic average of the two parallel measurement results is taken as the measurement result. Determination of methanol content reagent and material nitrogen: steel cylinders with purity of more than or equal to 99.999%; hydrogen gas: the purity is more than or equal to 99.999 percent. 4.8.2 instrument a) gas chromatograph: provided with a hydrogen flame ionization detector (GC 6890); b) Chromatographic column: HP-PLOT-Q (19091P-Q04); c) Recorder instrument: agilent gas phase workstation. After the start-up of the chromatograph in measurement step a), the necessary adjustments are made to achieve the following analytical conditions: column temperature: maintaining at 100deg.C for 3min, and 25 deg.C/min to 160deg.C for 2.5min; detecting the temperature: 300 ℃; sample inlet temperature: 180 ℃; carrier gas nitrogen: the flow rate (dried and purified by a 5A molecular sieve) is 1.8mL/min; gas hydrogen: the flow rate (dried and purified by a 5A molecular sieve) is 30mL/min; air: the flow rate (dried and purified by a 5A molecular sieve) is 300mL/min;
split ratio: 25:1; sample injection amount: 1.0. Mu.L. Qualitative: the relative retention value or the pure sample addition method is adopted. The quantitative method comprises the following steps: an internal standard method is adopted. d) And (3) measuring: correction factor measurement: 25mL of three-stage water is added into a 50mL grinding conical flask, 0.1g of methanol and 0.0001g of ethanol are respectively weighed, and the mixture is uniformly shaken by a cap plug. The gas chromatograph 6890 was turned on, and 0.4uL of standard sample was fed with a microinjector under prescribed operating conditions, and data were collected and processed using an agilent workstation. Sample treatment: 25g of paraformaldehyde is weighed, 75mL of distilled water is added, the mixture is put into a round bottom flask, the mixture is heated to 80-90 ℃, and the mixture is heated and condensed until the paraformaldehyde is completely dissolved, and the mass m1 of the solution is accurately weighed. Sample measurement: 40g of the treated formaldehyde solution and 0.1g of ethanol are weighed by the same method, and the methanol content is calculated by the same operation.
Claims (5)
1. A method for producing paraformaldehyde, comprising:
step one, raw material preparation: in a primary dryer, evaporating and concentrating formaldehyde aqueous solution with the mass concentration of 45-50% at the temperature of 45-48 ℃ until the formaldehyde weight concentration is 70-82%, preheating in an evaporator, then, performing vacuum evaporation and concentration in a flash evaporation separator, pumping into a secondary dryer after concentrating to 73-75%, and concentrating to 80-85% in a falling film evaporator; step two, boiling granulation: the concentrated formaldehyde solution after being concentrated to 80 to 85 percent is sent into a boiling granulator, and fine grain paraformaldehyde accounting for 5 to 10 percent of the mass ratio of the concentrated formaldehyde solution is continuously introduced into the granulator for continuous granulation; thirdly, drying after granulating to obtain paraformaldehyde with the concentration of 92% -96%, conveying the paraformaldehyde to a vibrating screen for screening through inert nitrogen flow, conveying the paraformaldehyde to a packaging system after screening, and packaging the paraformaldehyde.
2. The method for preparing paraformaldehyde according to claim 1, wherein the second-step boiling granulator is used for spraying feed liquid at a bed area of 0.66-0.73 m per square according to an air inlet temperature of 50-60 ℃ and an internal heater surface temperature of 50-60 ℃ and a bed temperature of 40-45% 3 And/h, the pressure of the compressed gas is 0.25-0.3 MPa, and the environment is 20-25 ℃.
3. The method for producing paraformaldehyde according to claim 1, wherein triethanolamine or hydroxylamine having a mass content of 0.5 to 1% is added to a raw material of an aqueous formaldehyde solution having a mass concentration of 45 to 50% at a temperature of 45 to 48 ℃.
4. The method for preparing paraformaldehyde as claimed in claim 1, wherein the formaldehyde and water vapor mixer extracted from the top of the primary dryer and the secondary dryer in the first step are fed into an absorption tower, and water is used as the absorption liquid.
5. The method for preparing paraformaldehyde according to claim 1, wherein the drying in the third step is further divided into primary drying or primary drying and secondary drying of a belt dryer, wherein the primary drying heating temperature is 60-65 ℃, the discharging temperature is 40-45 ℃, the secondary drying time is 0-4 h, the temperature is controlled to 80-90 ℃, and the discharging temperature is 50-55 ℃.
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Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT217214B (en) * | 1957-09-06 | 1961-09-11 | Du Pont | Process for the production of polyoxymethylene dieters |
| GB931892A (en) * | 1961-03-14 | 1963-07-24 | Ici Ltd | Stabilisation of formaldehyde |
| FR1485329A (en) * | 1965-07-02 | 1967-06-16 | Sir Soc Italiana Resine Spa | New process for preparing paraformaldehyde |
| FR1546360A (en) * | 1967-03-23 | 1968-11-15 | Sir Soc Italiana Resine Spa | Process for the production of paraformaldehyde |
| GB1234332A (en) * | 1968-03-20 | 1971-06-03 | ||
| US4550213A (en) * | 1984-06-29 | 1985-10-29 | Celanese Corporation | Method of manufacture for paraformaldehyde prills |
| GB8825238D0 (en) * | 1987-10-30 | 1988-11-30 | Synthite Ltd | Concentrating paraformaldehyde |
| DE3925966A1 (en) * | 1989-08-05 | 1991-02-07 | Leuna Werke Veb | Para-formaldehyde] granules prodn. |
| JPH09169717A (en) * | 1995-12-19 | 1997-06-30 | Toyo Eng Corp | Production of large granule urea |
| US5898087A (en) * | 1996-03-20 | 1999-04-27 | Celanese International Corporation | Addition of amine to improve parafomaldehyde |
| CN201411428Y (en) * | 2009-06-13 | 2010-02-24 | 江苏省范群干燥设备厂 | Production plant for preparation of paraformal-dehyde by condensation, polymerization, drying and granulation |
| WO2016011723A1 (en) * | 2014-07-21 | 2016-01-28 | 江苏凯茂石化科技有限公司 | Paraformaldehyde production method |
| CN109265632A (en) * | 2018-09-12 | 2019-01-25 | 重庆大学 | A kind of preparation method of paraformaldehyde |
-
2023
- 2023-08-15 CN CN202311035001.5A patent/CN117143303A/en active Pending
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT217214B (en) * | 1957-09-06 | 1961-09-11 | Du Pont | Process for the production of polyoxymethylene dieters |
| GB931892A (en) * | 1961-03-14 | 1963-07-24 | Ici Ltd | Stabilisation of formaldehyde |
| FR1485329A (en) * | 1965-07-02 | 1967-06-16 | Sir Soc Italiana Resine Spa | New process for preparing paraformaldehyde |
| FR1546360A (en) * | 1967-03-23 | 1968-11-15 | Sir Soc Italiana Resine Spa | Process for the production of paraformaldehyde |
| GB1234332A (en) * | 1968-03-20 | 1971-06-03 | ||
| US4550213A (en) * | 1984-06-29 | 1985-10-29 | Celanese Corporation | Method of manufacture for paraformaldehyde prills |
| GB8825238D0 (en) * | 1987-10-30 | 1988-11-30 | Synthite Ltd | Concentrating paraformaldehyde |
| DE3925966A1 (en) * | 1989-08-05 | 1991-02-07 | Leuna Werke Veb | Para-formaldehyde] granules prodn. |
| JPH09169717A (en) * | 1995-12-19 | 1997-06-30 | Toyo Eng Corp | Production of large granule urea |
| US5898087A (en) * | 1996-03-20 | 1999-04-27 | Celanese International Corporation | Addition of amine to improve parafomaldehyde |
| CN201411428Y (en) * | 2009-06-13 | 2010-02-24 | 江苏省范群干燥设备厂 | Production plant for preparation of paraformal-dehyde by condensation, polymerization, drying and granulation |
| WO2016011723A1 (en) * | 2014-07-21 | 2016-01-28 | 江苏凯茂石化科技有限公司 | Paraformaldehyde production method |
| CN109265632A (en) * | 2018-09-12 | 2019-01-25 | 重庆大学 | A kind of preparation method of paraformaldehyde |
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