CN114805026A - Process for recycling crude methanol in propylene oxide production process - Google Patents
Process for recycling crude methanol in propylene oxide production process Download PDFInfo
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- CN114805026A CN114805026A CN202210409175.2A CN202210409175A CN114805026A CN 114805026 A CN114805026 A CN 114805026A CN 202210409175 A CN202210409175 A CN 202210409175A CN 114805026 A CN114805026 A CN 114805026A
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- Prior art keywords
- methanol
- crude
- crude methanol
- rectifying tower
- recycling
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 title claims abstract description 414
- 238000000034 method Methods 0.000 title claims abstract description 49
- 238000004064 recycling Methods 0.000 title claims abstract description 24
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 238000002156 mixing Methods 0.000 claims abstract description 5
- 238000010992 reflux Methods 0.000 claims description 15
- 239000000872 buffer Substances 0.000 claims description 5
- 238000005086 pumping Methods 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 3
- 238000003860 storage Methods 0.000 claims description 3
- GBMDVOWEEQVZKZ-UHFFFAOYSA-N methanol;hydrate Chemical compound O.OC GBMDVOWEEQVZKZ-UHFFFAOYSA-N 0.000 claims description 2
- 238000000746 purification Methods 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract description 2
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 12
- 230000008901 benefit Effects 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 5
- HWOWEGAQDKKHDR-UHFFFAOYSA-N 4-hydroxy-6-(pyridin-3-yl)-2H-pyran-2-one Chemical compound O1C(=O)C=C(O)C=C1C1=CC=CN=C1 HWOWEGAQDKKHDR-UHFFFAOYSA-N 0.000 description 4
- 238000010924 continuous production Methods 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- ARXJGSRGQADJSQ-UHFFFAOYSA-N 1-methoxypropan-2-ol Chemical compound COCC(C)O ARXJGSRGQADJSQ-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 241000208125 Nicotiana Species 0.000 description 1
- 235000002637 Nicotiana tabacum Nutrition 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- XASUTLWDRZFPII-UHFFFAOYSA-N hydrogen peroxide;prop-1-ene Chemical compound OO.CC=C XASUTLWDRZFPII-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/02—Synthesis of the oxirane ring
- C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
- C07D301/12—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with hydrogen peroxide or inorganic peroxides or peracids
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
- C07D303/02—Compounds containing oxirane rings
- C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
Abstract
The invention provides a process for recycling crude methanol in the production process of propylene oxide, and relates to the technical field of propylene oxide production. The crude methanol recycling process mainly comprises the steps of mixing crude methanol in a methanol removing tower with feed of a methanol rectifying tower, rectifying, purifying and recycling, wherein the mode can realize two modes of continuous operation and intermittent operation aiming at actual production. The invention overcomes the defects of the prior art, effectively recycles the crude methanol by simply processing the crude methanol, changes the current situation of crude methanol waste, and simultaneously improves the environmental protection and safety of the production process.
Description
Technical Field
The invention relates to the technical field of propylene oxide production, in particular to a process for recycling crude methanol in the production process of propylene oxide.
Background
Propylene oxide is an important basic organic chemical raw material, and is the third largest organic chemical product with the yield second to that of polypropylene and acrylonitrile in propylene derivatives. The derivative is mainly used for producing polyether polyol, propylene glycol, polyurethane and the like, the derivative is also widely applied to industries such as food, tobacco, pesticide, cosmetics and the like, and the downstream products of the derivative are nearly hundreds of kinds and are important raw materials of fine chemical products.
The propylene hydrogen peroxide direct oxidation process (HPPO process) uses propylene and hydrogen peroxide as raw materials and methanol as a solvent to produce propylene oxide, and only a small amount of propylene glycol byproduct is produced. Compared with other processes, the HPPO method has the advantages of simple device design, environmental protection, only generating end products of propylene oxide and water in the production process, only generating a small amount of propylene glycol as a byproduct, and the like. An industrial structure adjustment instruction directory (2019) lists a process for producing propylene oxide by a direct oxidation method (HPPO method) as an incentive.
In the production process of propylene oxide by an HPPO method, propylene glycol and propylene glycol methyl ether are respectively separated from wastewater through a series of separation operations and sold as byproducts, so that the economic benefit of the device is improved, the concentration of organic matters in the wastewater can be reduced, and the difficulty in wastewater treatment is reduced. Wherein, a share of waste water is conveyed to the upper part of the methanol removing tower by a pump for rectification, rising steam at the tower top enters a reflux tank of the methanol removing tower after being cooled by a condenser of the methanol removing tower, one share of waste water is taken as reflux to enter the tower top of the methanol removing tower after being output by a reflux pump of the methanol removing tower, and the other share of waste water is conveyed to a crude methanol tank for caching. And conveying the crude methanol in the crude methanol tank to a crude methanol tank outside the device area through a crude methanol pump for harm or low-quality treatment. Therefore, the waste of crude methanol is caused, the cost is increased, and the equipment investment and the occupied area are increased due to the arrangement of a storage tank, a pump and the like which are matched with each other.
In the prior art, most of propylene oxide is produced by externally adding supplementary methanol, for example, as disclosed in application No. CN202110738373.9, namely 'a system and a method for continuously producing propylene oxide by using methanol in a two-step method', continuous production of propylene oxide is realized by adding methanol in a continuous phase system, although the continuity of propylene oxide production is ensured to a certain extent, a large amount of methanol is wasted in actual production, and certain pressure is brought to production and environmental protection.
In view of this, it is important to explore a process method for recycling crude methanol, which is flexible and stable in operation and simple in production process.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a process for recycling crude methanol in the production process of propylene oxide, which effectively recycles the crude methanol by simply processing the crude methanol, changes the current situation of crude methanol waste, and simultaneously improves the environmental protection and safety of the production process.
In order to achieve the above purpose, the technical scheme of the invention is realized by the following technical scheme:
a process for recycling crude methanol in the production process of propylene oxide comprises the following steps:
(1) mixing the crude methanol of the methanol removing tower with the feed of a methanol rectifying tower;
(2) and the mixed methanol enters a methanol rectifying tower for purification and then is used as circulating methanol.
Preferably, the purity of the crude methanol in the methanol removing tower is 70-95%, the flow rate is 0.1-5t/h, and the temperature is 30-60 ℃.
Preferably, the feeding flow rate of the methanol rectifying tower is 150-350t/h, the purity is 70-80%, the temperature is 90-110 ℃, and the pressure is 0.5-1.0 MPaG.
Preferably, the crude methanol and the feed of the methanol rectifying tower are uniformly mixed in a mixer and then enter the methanol rectifying tower as raw materials for methanol-water separation.
Preferably, the crude methanol recycling process can flexibly adjust an intermittent operation mode and a continuous operation mode according to production working conditions.
Wherein the intermittent operation mode is as follows: a coarse methanol buffer tank is arranged, and when the coarse methanol in the buffer tank reaches a certain storage amount, the coarse methanol is conveyed to a mixer by a pump to be mixed.
The continuous operation mode is: and directly pumping the crude methanol in the reflux tank of the methanol removing tower into a mixer to be mixed with the feed of the methanol rectifying tower.
Preferably, the methanol concentration obtained at the top of the methanol rectification column is 97% or more, and then the methanol is recycled.
The invention provides a process for recycling crude methanol in the production process of propylene oxide, which has the advantages compared with the prior art that:
(1) the method for recycling the crude methanol provided by the invention has the advantages that the crude methanol and the feed material of the methanol rectifying tower are directly mixed by the mixer and then purified by the rectifying tower to be used as the recycled methanol, the specific process flow is simple, the operation is flexible and convenient, the safety is high, the investment is small, and the method is suitable for being directly transformed on the existing equipment.
(2) The crude methanol recycling scheme provided by the invention can be operated intermittently or continuously, can temporarily store crude methanol when the methanol rectifying tower is in an abnormal working condition during intermittent operation, improves the safety, and is stable in overall operation during continuous operation, thereby being beneficial to the stable operation of the device.
(3) The crude methanol recycling scheme provided by the invention has the advantages of simple process flow and small operation difficulty; the equipment investment is small, the safety factor is high, the upgrading and reconstruction difficulty is small, and the implementation is easy.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
the continuous process for recycling the crude methanol comprises the following steps:
the continuous operation process comprises the following steps:
pumping crude methanol with the purity of 75%, the flow rate of 0.5t/h and the temperature of 50 ℃ into a mixer through a reflux pump of a methanol removal tower, mixing the crude methanol with the feed of a methanol rectifying tower, wherein the feed flow rate of the methanol rectifying tower is 300t/h, the purity of 75% and the temperature of 90 ℃, feeding the mixed material into the methanol rectifying tower for rectification, condensing the gas-phase methanol at the top of the tower, flowing into a reflux tank, taking part of the gas-phase methanol as reflux methanol, and taking part of the gas-phase methanol as circulating methanol for example.
Example 2:
the continuous process for recycling the crude methanol comprises the following steps:
the intermittent operation process comprises the following steps:
pumping crude methanol with the purity of 80%, the flow rate of 3t/h and the temperature of 40 ℃ into a mixer through a reflux pump of a methanol removal tower, mixing the crude methanol with the feed of a methanol rectifying tower, wherein the feed flow rate of the methanol rectifying tower is 200t/h, the purity of 80% and the temperature of 100 ℃, feeding the mixed material into the methanol rectifying tower for rectification, condensing gas-phase methanol at the top of the tower, flowing into a reflux tank, taking part of the gas-phase methanol as reflux methanol and taking part of the gas-phase methanol as circulating methanol for example;
in the operation, after the crude methanol tank buffers 100 hours of crude methanol, the extraction port is opened for recycling, and the time is 20 hours.
And (3) detection:
1. the methanol in the reflux tank at the top of the demethanizer, which is obtained by the continuous operation in the above example 1, was sampled and analyzed by the methanol concentration analysis method for industrial methanol in GB/T338-2011, and the specific results are shown in the following table 1:
TABLE 1
| Time/h | 1 | 5 | 10 | 20 | 50 | 100 | 150 | 200 |
| Concentration of methanol/%) | 99.4 | 98.9 | 99.2 | 99.4 | 99.2 | 99.2 | 99.1 | 99.2 |
As can be seen from Table 1, in the continuous process for recycling the crude methanol, the content of the crude methanol accounts for 0.17 percent of the mixture, the content is negligible, the operation of the methanol rectifying tower is not obviously affected, the methanol rectifying tower stably operates during the continuous operation of 200 hours, the purity of the methanol in the reflux tank is more than 99.9 percent, and the requirement of 97.8 percent of the circulating methanol is met.
2. The methanol in the reflux drum at the top of the demethanizer, which is obtained by the intermittent operation in example 2, was sampled and analyzed by the methanol concentration analysis method for industrial methanol in GB/T338-2011, and the specific results are shown in the following table 2:
TABLE 2
| Time/h | 1 | 5 | 10 | 15 | 20 |
| Concentration of methanol/%) | 98.4 | 98.6 | 98.4 | 98.7 | 98.6 |
As can be seen from Table 2, in the batch process for recycling the crude methanol, the crude methanol accounts for 1.47% of the mixture, has a small content, has a small influence on the methanol rectifying tower due to batch operation with a batch time of 20 hours, can be ignored, and can stably operate the methanol rectifying tower as a whole during the batch operation of 20 hours, the purity of the methanol in the reflux tank is more than 98.4%, and the requirement of 97.8% of the circulating methanol is met.
The detection proves that the crude methanol recycling process can realize the refining of the crude methanol, meets the use index of the circulating methanol, basically has no influence on the stable operation of the methanol rectifying tower, can realize the recycling of the crude methanol, and is an environment-friendly and economic process method.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A process for recycling crude methanol in the production process of propylene oxide is characterized by comprising the following steps:
(1) mixing the crude methanol of the methanol removing tower with the feed of a methanol rectifying tower;
(2) and the mixed methanol enters a methanol rectifying tower for purification and then is used as circulating methanol.
2. The process of claim 1, wherein the process comprises the following steps: the purity of the crude methanol in the methanol removing tower is 70-95%, the flow rate is 0.1-5t/h, and the temperature is 30-60 ℃.
3. The process of claim 1, wherein the process comprises the following steps: the feeding flow rate of the methanol rectifying tower is 150-350t/h, the purity is 70-80%, the temperature is 90-110 ℃, and the pressure is 0.5-1.0 MPaG.
4. The process for recycling crude methanol in the production process of propylene oxide according to claim 1, wherein: the crude methanol and the feed of the methanol rectifying tower enter a mixer to be uniformly mixed and then enter the methanol rectifying tower as raw materials for methanol-water separation.
5. The process of claim 1, wherein the process comprises the following steps: the crude methanol recycling process can flexibly adjust an intermittent operation mode and a continuous operation mode according to production working conditions.
6. The process of claim 5, wherein the batch mode of operation comprises:
a coarse methanol buffer tank is arranged, and when the coarse methanol in the buffer tank reaches a certain storage amount, the coarse methanol is conveyed to a mixer by a pump to be mixed.
7. The process of claim 5, wherein the continuous operation mode comprises:
and directly pumping the crude methanol in the reflux tank of the methanol removal tower into a mixer to be mixed with the feed of the methanol rectifying tower.
8. The process of claim 1, wherein the process comprises the following steps: the methanol concentration obtained from the top of the methanol rectifying tower reaches more than 97 percent and then is recycled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210409175.2A CN114805026A (en) | 2022-04-19 | 2022-04-19 | Process for recycling crude methanol in propylene oxide production process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210409175.2A CN114805026A (en) | 2022-04-19 | 2022-04-19 | Process for recycling crude methanol in propylene oxide production process |
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| Publication Number | Publication Date |
|---|---|
| CN114805026A true CN114805026A (en) | 2022-07-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210409175.2A Pending CN114805026A (en) | 2022-04-19 | 2022-04-19 | Process for recycling crude methanol in propylene oxide production process |
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| Country | Link |
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| CN (1) | CN114805026A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115490572A (en) * | 2022-09-16 | 2022-12-20 | 江苏嘉宏新材料有限公司 | Method for recycling crude methanol in propylene oxide production process |
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| CN107987037A (en) * | 2017-10-30 | 2018-05-04 | 河北美邦工程科技股份有限公司 | A kind of method that blocking prepares propylene oxide |
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| CN113968830A (en) * | 2020-07-24 | 2022-01-25 | 中国石油化工股份有限公司 | Method for separating propylene oxide stream, method for separating epoxidation reaction product, and method for epoxidizing propylene |
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2022
- 2022-04-19 CN CN202210409175.2A patent/CN114805026A/en active Pending
Patent Citations (6)
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| CN107987037A (en) * | 2017-10-30 | 2018-05-04 | 河北美邦工程科技股份有限公司 | A kind of method that blocking prepares propylene oxide |
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Application publication date: 20220729 |
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