CN102992951B - Method for preparing high-purity refined methanol by three-tower rectification - Google Patents
Method for preparing high-purity refined methanol by three-tower rectification Download PDFInfo
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- CN102992951B CN102992951B CN201210559385.6A CN201210559385A CN102992951B CN 102992951 B CN102992951 B CN 102992951B CN 201210559385 A CN201210559385 A CN 201210559385A CN 102992951 B CN102992951 B CN 102992951B
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 title claims abstract description 558
- 238000000034 method Methods 0.000 title claims abstract description 50
- 239000000047 product Substances 0.000 claims abstract description 40
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 30
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000012043 crude product Substances 0.000 claims abstract description 24
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 19
- 238000000605 extraction Methods 0.000 claims abstract description 19
- 238000009835 boiling Methods 0.000 claims abstract description 12
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 239000007788 liquid Substances 0.000 claims abstract description 12
- 239000008234 soft water Substances 0.000 claims abstract description 10
- 239000002699 waste material Substances 0.000 claims abstract description 9
- 238000007599 discharging Methods 0.000 claims abstract description 8
- 238000000926 separation method Methods 0.000 claims description 50
- 238000004821 distillation Methods 0.000 claims description 49
- 239000000470 constituent Substances 0.000 claims description 23
- 230000006835 compression Effects 0.000 claims description 16
- 238000007906 compression Methods 0.000 claims description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 8
- 238000007670 refining Methods 0.000 claims description 7
- 229910021529 ammonia Inorganic materials 0.000 claims description 5
- 230000006837 decompression Effects 0.000 claims description 5
- 238000000895 extractive distillation Methods 0.000 claims description 5
- 238000004064 recycling Methods 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 239000000126 substance Substances 0.000 abstract description 4
- 238000010992 reflux Methods 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 18
- 239000012535 impurity Substances 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 7
- 238000000746 purification Methods 0.000 description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- 150000001412 amines Chemical class 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 description 2
- 150000001299 aldehydes Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 150000002576 ketones Chemical class 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000000203 mixture Substances 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
- 238000009825 accumulation Methods 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 150000001728 carbonyl compounds Chemical class 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- CATSNJVOTSVZJV-UHFFFAOYSA-N heptan-2-one Chemical compound CCCCCC(C)=O CATSNJVOTSVZJV-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 239000000618 nitrogen fertilizer Substances 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 239000012476 oxidizable substance Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000000066 reactive distillation Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000000052 vinegar Substances 0.000 description 1
- 235000021419 vinegar Nutrition 0.000 description 1
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for preparing high-purity refined methanol by three-tower rectification, which is used for preparing high-purity refined methanol by treating a methanol crude product by using a three-tower rectification method. The method comprises the steps of: based on diluted alcohol water or soft water as an extraction agent, distilling in a pre-separating tower to remove low-boiling substances in the methanol crude product and water-insoluble gas so as to obtain pre-separated methanol; sending pre-separated methanol into a pressurizing tower for pressurized rectification treatment, cooling light components at the tower top of the pressurizing tower, returning a part of the light components to the tower top of the pressurizing tower for refluxing, and collecting the rest of the light components as the refined methanol product; sending heavy components at the tower bottom of the pressurizing tower into a main rectifying tower for rectification, cooling light components at the tower top of the main rectifying tower, returning a part of the light components to the tower top of the main rectifying tower for refluxing, and collecting the rest of the light components as the refined methanol product; and discharging the main rectifying tower bottom liquid as waste liquid. By using the 'three-tower rectification' method, the problem that methanol azeotropes cannot be separated in the methanol products is effectively solved, the purity of the obtained refined methanol product reaches more than 99.9%, the mass percent concentration of methanol in the discharged waste liquid is smaller than 1.0%, and the pollution of effluents to the environment is reduced because the methanol content is low.
Description
Technical field
The present invention relates to methanol production technical field, be specifically related to a kind of method that three-tower rectification prepares high purity extractive methyl alcohol.
Background technology
Methyl alcohol, as one of important basic organic chemical industry raw material, plays a very important role in world economy.Increasingly in short supply along with world energy sources, methyl alcohol progressively develops into again important energy substitution product, is that the Chemicals industries such as Material synthesis dme, alkene have also been obtained and develop rapidly with methyl alcohol.At present, 1/4 of China's methyl alcohol production capacity Yi Zhan world aggregated capacity, total capacity exceedes 2,900 ten thousand t/a.Develop the application with methanol fuel rapidly along with carbinol derivatives and derived product thereof, methanol demands amount also can be increasing, therefore improves methanol product quality, reduces the concern of producing and consuming and just more and more causing enterprise.Methanol rectification purification is last procedure of methanol production, and its energy consumption accounts for about 20% of methanol production total energy consumption.Because methanol rectification technology is directly connected to final obtained methanol product quality, be therefore also one important procedure in methanol production.Selecting appropriate rectification process, is reduce methanol production cost, energy-saving and cost-reducing, the Important Action that improves Business Economic Benefit and the market competitiveness.
At home and abroad after deliberation for a long time, disclosed technical publications is also more for refining methanol technology, and also has a lot of producer and research unit both at home and abroad also constantly studying this technology, also makes some progress.Refining methanol technology foreign study present situation: extract crude carbinol mainly through making extraction agent with water, removes the lower-boiling impurity such as ether, aldehyde, ketone lower than methyl alcohol boiling point, then rectifying separation water and Methanol obtain methanol product; Also have and adopting on the basis using water as extraction agent extracting rectifying removing lower-boiling impurity, then on rectifying tower subsequently, offer side line remove the impurity such as the ethanol of enrichment further, thus obtain the methyl alcohol of higher degree.Domestic research at present: use 732 type Zeo-karbs to eliminate readily oxidizable substance, organic substance (as aldehyde, ketone) and hydrogen, amine etc. in methyl alcohol, improve the purity of methyl alcohol, Be very effective; Or the process for purification of the thick alcohol adopting connection alcohol method to produce, adopt lateral line discharging, discharge wherein C
6~ C
10the alcohol dissolubility impurity accumulation such as higher alkane, increase the light constituent of the pre-tower of methanol rectification and the volatility of methyl alcohol, and increase the light constituent impurity such as condensation dynamics and the removal of pre-tower quantity of reflux dme, formaldehyde, methylamine, acetaldehyde, methyl-formiate, realize the object of refining methanol; Or by impurity such as the minor amount of water, acetone, first vinegar, formaldehyde, formic acid and the acetic acid that contain in batch reactive distillation integrated purification technology removing industrial methanol; Or by increasing the composition in the pre-tower of methyl alcohol and water-and-oil separator shared by extraction agent water, effectively improve water-soluble for methanol product of connection alcohol legal system.
The common issue that current methanol rectification faces is that methanol azeotrope impurity in crude carbinol is as dimethyl carbonate etc., the mixture that the meeting of these impurity is identical with the formation of methanol boiling point, extremely difficult separation, current rectification and purification method cannot isolate these methanol azeotrope impurity, so that the purity of methanol product cannot improve, obtained methanol product best level also can only reach purity 99.5%, and quality is difficult to stable.And alcohol content is high in methanol rectified raffinate, in raffinate, methanol quality percentage concentration is generally more than 3%, serious environment pollution in the process of discharge.Steam consumption cannot make a breakthrough all the time in addition, and current ton methanol rectification consumes steam generally at 1.5 ~ 1.8 tons.
Summary of the invention
The object of this invention is to provide a kind of method that three-tower rectification prepares high purity extractive methyl alcohol.
In order to realize above object, the technical solution adopted in the present invention is: a kind of three-tower rectification prepares the method for high purity extractive methyl alcohol, comprises the following steps:
(1) pre-separation tower extractive distillation
With rare alcohol water or soft water for extraction agent, methyl alcohol crude product is preheated to 70 ~ 90 DEG C, send in the middle part of pre-separation tower, add extraction agent on pre-separation tower top, the flow of extraction agent is 20 ~ 40% of methyl alcohol crude product flow, and it is 30 ~ 60Kpa that pre-separation tower tower bottom pressure controls, column bottom temperature is 78 ~ 84 DEG C, tower top temperature is 65 ~ 72 DEG C, and by distillation methanol removal crude product, low-boiling point material is as ethers, amine etc., the gas being insoluble in water simultaneously in methanol removal crude product is as CO, CO
2, CH
4deng, obtained pre-separation methyl alcohol, pre-separation column overhead recycling of condensed steam, noncondensable gas emptying;
(2) pressurizing tower compression rectification process
Pre-separation methyl alcohol is heated to 100 ~ 120 DEG C, in the middle part of pressurizing tower, send into pressurizing tower carry out compression rectification, it is 500 ~ 700Kpa that pressurizing tower internal pressure controls, pressurizing tower column bottom temperature is 120 ~ 135 DEG C, tower top temperature is 115 ~ 125 DEG C, compression rectification improves the envrionment temperature that methanol azeotrope is separated, methanol azeotrope detachment dynamic significantly improves, the light constituent that pressurizing tower tower top obtains turns back to pressurizing tower trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, the restructuring obtained at the bottom of pressurizing tower tower is divided into rarer methanol solution,
(3) main distillation column rectification process
The heavy constituent obtained at the bottom of pressurizing tower tower carries out rectifying by sending into main distillation column in the middle part of main distillation column after decompression, main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 15 ~ 50Kpa that tower internal pressure controls, the light constituent that main distillation column tower top obtains turns back to main distillation column trim the top of column through cooling rear portion, and remainder collects methyl alcohol pan tank, obtains high purity extractive methanol product, non-condensable gas emptying, main distillation column kettle base solution is as discharging of waste liquid.
What described rare alcohol water was that in synthetic ammonia connection alcohol technique copper washing-refining post water wash column produces is the soft water of 2 ~ 5% containing methanol quality percentage ratio.
In step (1), the proportion of the pre-separation methyl alcohol obtained is 0.82 ~ 0.87g/cm
3.
The pH value of pre-separation methyl alcohol is 6.5 ~ 8.5.In order to impel the decomposition of amine in methyl alcohol crude product, carbonyl class, carbonyl compound, prevent the organic acid in methyl alcohol crude product from producing corrosion to rectifying device, the pH value of pre-separation methyl alcohol controls to be 6.5 ~ 8.5.
Purity >=99.9% of the high purity extractive methanol product obtained.
Mass percent concentration≤1.0% of methyl alcohol in main distillation column kettle base solution.
In step (1), the consumption of extraction agent controls very crucial, control suitable consumption and can ensure that effect of extracting is good, effectively can remove the low-boiling point material in methyl alcohol crude product and the gas being insoluble in water, in the present invention, the flow control of extraction agent is 20 ~ 40% of methyl alcohol crude product flow.
Three-tower rectification provided by the invention prepares the method for high purity extractive methyl alcohol, using rare alcohol water or soft water as extraction agent, first the low-boiling point material in methyl alcohol crude product and the gas being insoluble in water is removed, then enter pressurizing tower and carry out compression rectification process, pressurizing tower adopts bubble point temperature charging, 100 ~ 120 DEG C are heated to by pre-separation methyl alcohol, then send into pressurizing tower and carry out rectification process, feeding temperature is important control index, ensure bubble point temperature charging, the most reasonably could utilize the heat energy of reboiler, reduce steam consumption, controlling pressurizing tower internal pressure is 500 ~ 700Kpa, namely the pressure improved in rectifying tower by compression rectification improves the envrionment temperature that methanol azeotrope is separated, the column bottom temperature of compression rectification tower can reach 120 ~ 135 DEG C, the detachment dynamic of methanol azeotrope significantly improves, efficiently solve the separation problem of methanol azeotrope, the purity of product is made to reach more than 99.9%, main distillation column is adopted to carry out rectification process to the heavy constituent obtained at the bottom of liquid at the bottom of compression rectification tower tower and pressurizing tower tower afterwards, to remove the high-boiling-point impurity in liquid at the bottom of compression rectification tower tower, as different heptanone, isobutyl-wet goods, controlling main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 15 ~ 50Kpa that tower internal pressure controls, the further methyl alcohol reclaimed in heavy constituent at the bottom of pressurizing tower tower, and mass percent concentration≤1.0% of methyl alcohol in the main distillation column kettle base solution obtained can be ensured, reduce the content of methyl alcohol in relief liquor, decrease the pollution of discharge to environment.
Three-tower rectification provided by the invention is adopted to prepare the method for high purity extractive methyl alcohol, the purity of the refined methanol product that process methyl alcohol crude product obtains reaches more than 99.9%, namely in refined methanol, the mass percent concentration of methyl alcohol reaches more than 99.9%, and methanol product purity significantly improves.And the mass percent concentration discharging methyl alcohol in waste liquid and main distillation column kettle base solution is down to less than 1.0%, methanol content is low, decreases the pollution of discharge to environment.
Three-tower rectification provided by the invention prepares the method for high purity extractive methyl alcohol, improve the output more than 50% of high purity methanol, obtain more highly purified refined methanol, product purity brings up to more than 99.9% from current 99.0%, constant product quality, and reduce steam consumption, ton methyl alcohol consumption steam also drops to 0.87 ~ 1.0t from 1.5 ~ 1.8t, the discharge of methanol residue will be reduced simultaneously, in raffinate, the mass percent concentration of methyl alcohol is reduced to less than 1.0% from more than 3.0%, thus greatly reduces environmental pollution.
Three-tower rectification provided by the invention prepares the method for high purity extractive methyl alcohol, for China's methanol purification has explored a new operational path, can be national small nitrogen fertilizer business and play good exemplary role, thus drive the development of China's synthetic ammonia connection alcohol production and methyl alcohol industry.The preparation method of high purity methanol provided by the invention can be generalized to the separating methanol workshop section of other companies, and even on other organic separating technologies, there is considerable economic benefit and long-range social benefit.
Embodiment
Below by specific embodiment, technical scheme of the present invention is described in detail.
Embodiment 1
The three-tower rectification that the present embodiment provides prepares the method for high purity extractive methyl alcohol, comprises the following steps:
(1) pre-separation tower extractive distillation
With rare alcohol water for extraction agent, what this rare alcohol water was that in synthetic ammonia connection alcohol technique copper washing-refining post water wash column produces is the soft water of 2% containing methanol quality percentage ratio, methyl alcohol crude product is preheated to 70 DEG C, send in the middle part of pre-separation tower, the rare alcohol water of extraction agent is added on pre-separation tower top, the flow of rare alcohol water is 20% of methyl alcohol crude product flow, it is 40 ~ 60Kpa that pre-separation tower tower bottom pressure controls, column bottom temperature is 78 ~ 84 DEG C, tower top temperature is 65 ~ 72 DEG C, by low-boiling point material in distillation methanol removal crude product and the gas being insoluble in water, obtain pre-separation methyl alcohol, pre-separation column overhead recycling of condensed steam, noncondensable gas emptying, the proportion of pre-separation methyl alcohol is 0.84g/cm
3, the pH value of pre-separation methyl alcohol is 8.0,
(2) pressurizing tower compression rectification process
Pre-separation methyl alcohol is heated to 110 DEG C, in the middle part of pressurizing tower, send into pressurizing tower carry out compression rectification, it is 500 ~ 700Kpa that pressurizing tower internal pressure controls, pressurizing tower column bottom temperature is 120 ~ 135 DEG C, and tower top temperature is 115 ~ 125 DEG C, and the light constituent that pressurizing tower tower top obtains turns back to pressurizing tower trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, at the bottom of pressurizing tower tower, obtain heavy constituent;
(3) main distillation column rectification process
The heavy constituent obtained at the bottom of pressurizing tower tower carries out rectifying by sending into main distillation column in the middle part of main distillation column after decompression, main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 35 ~ 50Kpa that tower internal pressure controls, the light constituent that main distillation column tower top obtains turns back to main distillation column trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, main distillation column kettle base solution is as discharging of waste liquid, in main distillation column kettle base solution, the mass percent concentration of methyl alcohol is 0.9%, the purity of refined methanol product is 99.91%.
The method that the three-tower rectification adopting the present embodiment to provide prepares high purity extractive methyl alcohol prepares methanol product, and methanol product consumption steam per ton is 0.95 ton.
Embodiment 2
The three-tower rectification that the present embodiment provides prepares the method for high purity extractive methyl alcohol, comprises the following steps:
(1) pre-separation tower extractive distillation
With rare alcohol water for extraction agent, what this rare alcohol water was that in synthetic ammonia connection alcohol technique copper washing-refining post water wash column produces is the soft water of 5% containing methanol quality percentage ratio, methyl alcohol crude product is preheated to 80 DEG C, send in the middle part of pre-separation tower, the rare alcohol water of extraction agent is added on pre-separation tower top, the flow of rare alcohol water is 40% of methyl alcohol crude product flow, it is 30 ~ 50Kpa that pre-separation tower tower bottom pressure controls, column bottom temperature is 78 ~ 84 DEG C, tower top temperature is 65 ~ 72 DEG C, by low-boiling point material in distillation methanol removal crude product and the gas being insoluble in water, obtain pre-separation methyl alcohol, pre-separation column overhead recycling of condensed steam, noncondensable gas emptying, the proportion of pre-separation methyl alcohol is 0.82g/cm
3, the pH value of pre-separation methyl alcohol is 8.5,
(2) pressurizing tower compression rectification process
Pre-separation methyl alcohol is heated to 100 DEG C, in the middle part of pressurizing tower, send into pressurizing tower carry out compression rectification, it is 500 ~ 600Kpa that pressurizing tower internal pressure controls, pressurizing tower column bottom temperature is 120 ~ 135 DEG C, and tower top temperature is 115 ~ 125 DEG C, and the light constituent that pressurizing tower tower top obtains turns back to pressurizing tower trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, at the bottom of pressurizing tower tower, obtain heavy constituent;
(3) main distillation column rectification process
The heavy constituent obtained at the bottom of pressurizing tower tower carries out rectifying by sending into main distillation column in the middle part of main distillation column after decompression, main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 15 ~ 30Kpa that tower internal pressure controls, the light constituent that main distillation column tower top obtains turns back to main distillation column trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, main distillation column kettle base solution is as discharging of waste liquid, in main distillation column kettle base solution, the mass percent concentration of methyl alcohol is 0.86%, the purity of refined methanol product is 99.94%.
The method that the three-tower rectification adopting the present embodiment to provide prepares high purity extractive methyl alcohol prepares methanol product, and methanol product consumption steam per ton is 1.0 tons.
Embodiment 3
The three-tower rectification that the present embodiment provides prepares the method for high purity extractive methyl alcohol, comprises the following steps:
(1) pre-separation tower extractive distillation
Take soft water as extraction agent, methyl alcohol crude product is preheated to 90 DEG C, send in the middle part of pre-separation tower, extraction agent soft water is added on pre-separation tower top, the flow of soft water is 30% of methyl alcohol crude product flow, it is 30 ~ 45Kpa that pre-separation tower tower bottom pressure controls, column bottom temperature is 78 ~ 84 DEG C, tower top temperature is 65 ~ 72 DEG C, by low-boiling point material in distillation methanol removal crude product and the gas being insoluble in water, obtain pre-separation methyl alcohol, pre-separation column overhead recycling of condensed steam, noncondensable gas emptying, the proportion of pre-separation methyl alcohol is 0.87g/cm
3, the pH value of pre-separation methyl alcohol is 6.5;
(2) pressurizing tower compression rectification process
Pre-separation methyl alcohol is heated to 120 DEG C, in the middle part of pressurizing tower, send into pressurizing tower carry out compression rectification, it is 550 ~ 650Kpa that pressurizing tower internal pressure controls, pressurizing tower column bottom temperature is 120 ~ 135 DEG C, and tower top temperature is 115 ~ 125 DEG C, and the light constituent that pressurizing tower tower top obtains turns back to pressurizing tower trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, at the bottom of pressurizing tower tower, obtain heavy constituent;
(3) main distillation column rectification process
The heavy constituent obtained at the bottom of pressurizing tower tower carries out rectifying by sending into main distillation column in the middle part of main distillation column after decompression, main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 20 ~ 40Kpa that tower internal pressure controls, the light constituent that main distillation column tower top obtains turns back to main distillation column trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, main distillation column kettle base solution is as discharging of waste liquid, in main distillation column kettle base solution, the mass percent concentration of methyl alcohol is 0.91%, the purity of refined methanol product is 99.97%.
The method that the three-tower rectification adopting the present embodiment to provide prepares high purity extractive methyl alcohol prepares methanol product, and methanol product consumption steam per ton is 0.87 ton.
The method adopting the three-tower rectification that provides of the embodiment of the present invention 1 to prepare high purity extractive methyl alcohol carries out the Economic and Efficiency Analysis of methanol production: should turn to example with Hunan, methanol 63651 tons in 2010, high purity methanol product production improves 50%, and by improving the quality of products, the benefit created is:
63651 × 50% × (2000-1100)=2864.3 ten thousand yuan,
In waste liquid, the mass percentage content of residual methanol drops to 0.9% from 3%, and benefit is:
63651 × (3%-0.9%) × 2000=267.3 ten thousand yuan,
Reduce ton methanol steam and consume 800kg, steam cost is by 100 yuan/ton of calculating, and benefit is:
63651 × 0.8 × 100 yuan/ton=509.2 ten thousand yuan,
Amount to wound economic benefit 3640.8 ten thousand yuan, economic benefit is considerable.
Claims (5)
1. three-tower rectification prepares a method for high purity extractive methyl alcohol, it is characterized in that, comprises the following steps:
(1) pre-separation tower extractive distillation
Methyl alcohol crude product is preheated to 70 ~ 90 DEG C, send in the middle part of pre-separation tower, with rare alcohol water for extraction agent, add described extraction agent on pre-separation tower top, the flow of extraction agent is 20 ~ 40% of methyl alcohol crude product flow, it is 30 ~ 60KPa that pre-separation tower tower bottom pressure controls, and column bottom temperature is 78 ~ 84 DEG C, and tower top temperature is 65 ~ 72 DEG C, by low-boiling point material in distillation methanol removal crude product and the gas being insoluble in water, obtain pre-separation methyl alcohol, pre-separation column overhead recycling of condensed steam, noncondensable gas emptying;
Wherein, what described rare alcohol water was that in synthetic ammonia connection alcohol technique copper washing-refining post water wash column produces is the soft water of 2 ~ 5% containing methanol quality percentage ratio;
(2) pressurizing tower compression rectification process
Pre-separation methyl alcohol is heated to 100 ~ 120 DEG C, in the middle part of pressurizing tower, send into pressurizing tower carry out compression rectification, it is 500 ~ 700KPa that pressurizing tower internal pressure controls, pressurizing tower column bottom temperature is 120 ~ 135 DEG C, and tower top temperature is 115 ~ 125 DEG C, and the light constituent that pressurizing tower tower top obtains turns back to pressurizing tower trim the top of column through cooling rear portion, remainder collects methyl alcohol pan tank, obtain high purity extractive methanol product, non-condensable gas emptying, at the bottom of pressurizing tower tower, obtain heavy constituent;
(3) main distillation column rectification process
The heavy constituent obtained at the bottom of pressurizing tower tower carries out rectifying by sending into main distillation column in the middle part of main distillation column after decompression, main distillation column column bottom temperature is 102 ~ 108 DEG C, tower top temperature is 64 ~ 66 DEG C, it is 15 ~ 50KPa that tower internal pressure controls, the light constituent that main distillation column tower top obtains turns back to main distillation column trim the top of column through cooling rear portion, and remainder collects methyl alcohol pan tank, obtains high purity extractive methanol product, non-condensable gas emptying, main distillation column kettle base solution is as discharging of waste liquid.
2. three-tower rectification according to claim 1 prepares the method for high purity extractive methyl alcohol, it is characterized in that, the proportion of described pre-separation methyl alcohol is 0.82 ~ 0.87.
3. three-tower rectification according to claim 1 prepares the method for high purity extractive methyl alcohol, it is characterized in that, the pH value of pre-separation methyl alcohol is 6.5 ~ 8.5.
4. prepare the method for high purity extractive methyl alcohol according to the arbitrary described three-tower rectification of claim 1-3, it is characterized in that, purity >=99.9% of high purity extractive methanol product.
5. three-tower rectification according to claim 4 prepares the method for high purity extractive methyl alcohol, it is characterized in that, mass percent concentration≤1.0% of methyl alcohol in main distillation column kettle base solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210559385.6A CN102992951B (en) | 2012-12-20 | 2012-12-20 | Method for preparing high-purity refined methanol by three-tower rectification |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210559385.6A CN102992951B (en) | 2012-12-20 | 2012-12-20 | Method for preparing high-purity refined methanol by three-tower rectification |
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| CN109678667A (en) * | 2019-01-22 | 2019-04-26 | 安徽昊源化工集团有限公司 | A kind of crude carbinol isolation and purification method |
| CN114426462A (en) * | 2020-10-15 | 2022-05-03 | 中国石油化工股份有限公司 | Device and method for removing trimethylamine and/or heavy alcohol in methanol |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1817836A (en) * | 2006-03-10 | 2006-08-16 | 天津大学 | Double-efficient energy-saving and water-saving rectifying system and process for methanol |
| CN1931807A (en) * | 2006-09-29 | 2007-03-21 | 浙江大学 | A method for rectifying and refining synthetic crude methanol |
| CN101130484A (en) * | 2007-09-07 | 2008-02-27 | 中国寰球工程公司 | Pressure-reducing flow-reversing dual-purpose distillation method and apparatus for refining crude methanol |
| CN101357879A (en) * | 2008-09-10 | 2009-02-04 | 兖矿鲁南化肥厂 | Methanol three-tower rectification system and technique |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1817836A (en) * | 2006-03-10 | 2006-08-16 | 天津大学 | Double-efficient energy-saving and water-saving rectifying system and process for methanol |
| CN1931807A (en) * | 2006-09-29 | 2007-03-21 | 浙江大学 | A method for rectifying and refining synthetic crude methanol |
| CN101130484A (en) * | 2007-09-07 | 2008-02-27 | 中国寰球工程公司 | Pressure-reducing flow-reversing dual-purpose distillation method and apparatus for refining crude methanol |
| CN101357879A (en) * | 2008-09-10 | 2009-02-04 | 兖矿鲁南化肥厂 | Methanol three-tower rectification system and technique |
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