A process for the recycle of a fixed bed of fusel oil hydrolysis products
Patent Information
- Application Number
- CN202510572121.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2026-10-30
AI Technical Summary
合成气通过草酸酯法生产乙二醇或乙醇酸甲酯，都会在工艺过程中产生大量的混合醇及多元醇，有些废液中杂质组分较多，各物质的沸点接近，还有一些以共沸物形式存在，导致各组分难以分离
[0009]本发明的方法解决了草酸酯法合成路线上的杂醇油的处理问题，在杂醇油醇解后回收高附加值组分(乙醇酸甲酯和乙二醇)。保证醇解反应选择性的同时，减少杂质累计循环，减少能耗，使杂醇油醇解技术能很好的嵌入到乙醇酸甲酯生产工艺中，不影响后续产品质量，经济实用性好，操作灵活性强，最大程度增产乙醇酸酯类及乙二醇，提高经济效益。
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Figure CN123003373A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fusel oil processing technology, and more specifically, to a method for recycling fusel oil fixed-bed alcoholysis products. Background Technology
[0002] With the large-scale industrial application of coal-to-ethylene glycol (CGE) technology via syngas in my country, and the increasingly sophisticated hydrogenation technology for dimethyl oxalate (DMO), researchers have further developed coal-to-methyl glycolate (MG) technology. This involves further direct polymerization of MG (or hydrolysis and crystallization of MG to obtain glycolic acid (GA) followed by polymerization) to prepare the biodegradable material PGA. The production of CGE or methyl glycol from syngas via the oxalate ester process generates large quantities of mixed alcohols and polyols. Some waste liquids contain numerous impurities with similar boiling points, and some exist as azeotropes, making separation difficult. Fusel oil from CGE production is almost always sold directly (without recycling), resulting in low market prices and increasingly large stockpiles, becoming a concern and burden for production. There is an urgent need to explore a comprehensive utilization method for fusel oil from this process route. Summary of the Invention
[0003] The purpose of this invention is to provide a fixed-bed alcoholysis product recycling method for fusel oil. This method solves the problem of fusel oil treatment in the oxalate ester synthesis route, recovering high-value-added components after fusel oil alcoholysis. While ensuring the selectivity of the alcoholysis reaction, it reduces the accumulation of impurities during recycling, reduces energy consumption, and allows the fusel oil alcoholysis technology to be well integrated into the methyl glycolate production process without affecting the quality of subsequent products. It is economical, practical, and highly flexible in operation, maximizing the production of glycolates and ethylene glycol, thereby improving economic efficiency.
[0004] To achieve the above objectives, the present invention provides a method for recycling fusel oil fixed-bed alcoholysis products, the method comprising:
[0005] (1) Fusel oil and methanol from the separation unit of the original methyl glycolate production unit are fed into the fixed-bed alcoholysis reaction unit.
[0006] (2) The product of the fixed-bed alcoholysis reaction unit is fed into the fixed-bed alcoholysis separation unit, and the light component, the circulating methanol stream, the methyl glycol-rich, ethylene glycol and methanol stream, and the ethylene glycol and recombinant fraction are separated by the fixed-bed alcoholysis separation unit.
[0007] (3) The circulating methanol stream is returned to the fixed-bed alcoholysis reaction unit, and the methyl glycolate, ethylene glycol and methanol stream is returned to the separation unit of the original methyl glycolate production unit; preferably, the content of the residual heavy components in the methyl glycolate, ethylene glycol and methanol stream is less than 5 wt% based on the total weight of the methyl glycolate, ethylene glycol and methanol stream.
[0008] The technical solution of the present invention has the following beneficial effects:
[0009] The method of this invention solves the problem of fusel oil treatment in the oxalate synthesis route, recovering high-value-added components (methyl glycolate and ethylene glycol) after the alcoholysis of the fusel oil. While ensuring the selectivity of the alcoholysis reaction, it reduces the accumulation and recycling of impurities, reduces energy consumption, and allows the fusel oil alcoholysis technology to be well integrated into the methyl glycolate production process without affecting the quality of subsequent products. It is economical, practical, and highly flexible in operation, maximizing the production of glycolates and ethylene glycol, thereby improving economic efficiency.
[0010] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0011] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
[0012] Figure 1 A flowchart of a fixed-bed alcoholysis product recycling method for fusel oil according to an embodiment of the present invention is shown.
[0013] Figure 2 A flowchart of a fixed-bed alcoholysis product recycling method for fusel oil according to a comparative example is shown. Detailed Implementation
[0014] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.
[0015] This invention provides a method for recycling fusel oil fixed-bed alcoholysis products, the method comprising:
[0016] (1) Fusel oil and methanol from the separation unit of the original methyl glycolate production unit are fed into the fixed-bed alcoholysis reaction unit.
[0017] (2) The product of the fixed-bed alcoholysis reaction unit is fed into the fixed-bed alcoholysis separation unit, and the light component, the circulating methanol stream, the methyl glycol-rich, ethylene glycol and methanol stream, and the ethylene glycol and recombinant fraction are separated by the fixed-bed alcoholysis separation unit.
[0018] (3) The circulating methanol stream is returned to the fixed-bed alcoholysis reaction unit, and the methyl glycolate, ethylene glycol and methanol stream is returned to the separation unit of the original methyl glycolate production unit; preferably, the content of the residual heavy components in the methyl glycolate, ethylene glycol and methanol stream is less than 5 wt% based on the total weight of the methyl glycolate, ethylene glycol and methanol stream.
[0019] In this invention, preferably, the heavy components include: high-boiling polymers, optional other diols, and optional heavy impurities; the content of the heavy components remaining in the methyl glycolate, ethylene glycol, and methanol streams is less than 5 wt% based on the total weight of the methyl glycolate, ethylene glycol, and methanol streams.
[0020] According to the present invention, preferably, the fusel oil comprises: small molecule compounds, high-boiling polymers, and optional heavy impurities;
[0021] The small molecule compounds include: ethylene glycol, optionally glycolic acid, optionally methyl glycolate, and optionally other diols;
[0022] The high-boiling polymer is a polymer generated by polymerization of at least one of ethylene glycol, glycolic acid, and methyl glycolate.
[0023] Preferably, the pH value of the fusel oil is 2-6.
[0024] According to the present invention, preferably, the content of the high-boiling polymer is not less than 5 wt%, and more preferably 10-80 wt%, based on the total weight of the fusel oil;
[0025] The content of ethylene glycol is 15-80 wt%, the content of methyl glycolate is 0-30 wt%, the content of glycolic acid is 0-10 wt%, the content of other diols is 0-40 wt%, and the content of heavy impurities is 0-5 wt%.
[0026] In this invention, depending on the source of the fusel oil, in addition to the aforementioned common components, the fusel oil may optionally contain trace amounts of non-common components, such as dimethyl oxalate.
[0027] In this invention, the separation method used in the fixed-bed alcoholysis separation unit can be distillation, distillation concentration, adsorption, or extraction, etc.; preferably, it is distillation; the distillation can be atmospheric distillation, vacuum distillation, or pressurized distillation; according to this invention, more preferably, the separation method used in the fixed-bed alcoholysis separation unit is atmospheric distillation or vacuum distillation;
[0028] Preferably, the atmospheric distillation is carried out under conditions of 101-201 kPa and 60-240°C; the vacuum distillation is carried out under conditions of 5 Pa-100 kPa and 40-220°C.
[0029] According to the present invention, preferably, the content of methanol in the light components is <99 wt% based on the total weight of the light components;
[0030] Based on the total weight of the circulating methanol stream, the content of circulating methanol in the circulating methanol stream is ≥99wt%.
[0031] According to the present invention, preferably, the amount of recycled methanol contained in the recycled methanol stream accounts for 10-95 wt% of the methanol content in the reaction product of the fixed-bed alcoholysis reaction unit, preferably 20-95 wt%, and more preferably 40-90 wt%.
[0032] According to the present invention, preferably, the fixed-bed alcoholysis reaction unit is a fixed-bed alcoholysis reactor.
[0033] According to the present invention, preferably, the reaction pressure in the fixed-bed alcoholysis reaction unit is 0.1-4 MPa;
[0034] The reaction temperature is 80-250℃.
[0035] According to the present invention, preferably, the space velocity in the fixed-bed alcoholysis reaction unit is 0.5-5 h⁻¹. -1 .
[0036] According to the present invention, preferably, the catalyst used in the fixed-bed alcoholysis reaction unit is a metal oxide catalyst, preferably a zinc oxide catalyst and / or a copper oxide catalyst, and more preferably a zinc oxide catalyst.
[0037] The fusel oil in methyl glycolate production plants is rich in various esters and oligomers. The method of this invention employs a fixed-bed catalytic alcoholysis technology, which can achieve efficient alcoholysis of high-boiling-point substances such as esters and oligomers, recovering glycolates and ethylene glycol. While ensuring the selectivity of the alcoholysis reaction, it reduces the accumulation and recycling of impurities, reduces energy consumption, and allows the fusel oil alcoholysis technology to be well integrated into the methyl glycolate production process without affecting product quality. It is economical, practical, and highly flexible in operation, maximizing the production of glycolates and ethylene glycol.
[0038] The present invention is further illustrated by the following examples:
[0039] In the following embodiments and comparative examples:
[0040] The catalyst used in the fixed-bed alcoholysis reaction unit is a zinc oxide catalyst, purchased from Beijing Research Institute of Chemical Industry, with the brand name brici-zn-01.
[0041] The composition of the components was determined using gas chromatography according to the normalization method. The type and content of each component were determined by chromatographic peaks. The specific molecular structures of heavy impurities and high-boiling polymers were difficult to determine. However, their retention times in the chromatograms were fixed, and the content of high-boiling polymers decreased significantly after the reaction, while the content of heavy impurities increased slightly before and after the reaction. This allowed for the determination of the type and content of each component.
[0042] Example 1
[0043] The mass flow rate of the separation unit from the original methyl glycolate production unit was 1643 kg / h. The fusel oil, based on its total weight, consisted of 6.5 wt% other diols, 58.25 wt% ethylene glycol, 0.25 wt% heavy impurities, and 35.00 wt% high-boiling polymers. The fusel oil had a pH of 3.1. Additionally, 1950 kg / h of methanol and 5000 kg / h of circulating methanol from the fixed-bed alcoholysis separation unit were fed into the fixed-bed alcoholysis reaction unit (fixed-bed alcoholysis reactor). The reaction was carried out at a temperature of 180°C, a pressure of 2 MPa, and a space velocity of 1 h⁻¹. -1 Under these conditions, the flow rate of the liquid-phase alcoholysis reaction product was 8593 kg / h, and the composition was 73.56 wt% methanol, 7 wt% methyl glycolate, 17.24 wt% ethylene glycol, 1.31 wt% other diols, 0.16 wt% methyl acetate, 0.47 wt% high-boiling polymer, and 0.26 wt% heavy impurities.
[0044] The product from the fixed-bed alcoholysis reaction unit is fed into a fixed-bed alcoholysis separation unit (distillation column). Under conditions of a top temperature of 72.0°C, a bottom temperature of 213.0°C, a pressure of 135 kPa, 70 trays, and a top reflux ratio of 20, methanol with a mass flow rate of 280 kg / h and a purity of 96.6 wt% is collected from the top of the column as a light component. Methanol with a mass flow rate of 5000 kg / h and a purity of 99.89 wt% is collected from the side stream and returned to the fixed-bed alcoholysis reaction unit as a circulating methanol stream. The side stream, with a mass flow rate of 3050 kg / h, comprises, by weight, 34.63 wt% methanol, 19.8 wt% methyl glycolate, 43.21 wt% ethylene glycol, 1.5 wt% other diols, 0.39 wt% high-boiling polymers, and 0.47 wt% heavy impurities. This liquid phase is used as the methyl glycolate-rich, ethylene glycol-rich, and methanol-rich stream. A 264 kg / h ethylene glycol and heavy fraction stream is collected from the bottom of the column. By weight, this stream comprises 61.86 wt% ethylene glycol, 25 wt% other diols, 10.8 wt% high-boiling polymers, and 2.34 wt% heavy impurities (the other diols, high-boiling polymers, and heavy impurities are heavy components). The methyl glycolate-rich, ethylene glycol-rich, and methanol-rich stream is returned to the separation unit of the original methyl glycolate production unit.
[0045] Example 2
[0046] The mass flow rate of the separation unit from the original methyl glycolate production unit was 1688 kg / h. The fusel oil, based on its total weight, consisted of 11.4 wt% other diols, 54.09 wt% ethylene glycol, 0.61 wt% heavy impurities, and 33.9 wt% high-boiling polymers. The fusel oil had a pH of 3.3. It was fed into the fixed-bed alcoholysis reaction unit (fixed-bed alcoholysis reactor) along with 5950 kg / h of methanol and a 1000 kg / h circulating methanol stream from the fixed-bed alcoholysis separation unit. The reaction was carried out at a temperature of 180°C, a pressure of 2 MPa, and a space velocity of 1 h⁻¹. -1 Under these conditions, the flow rate of the liquid-phase alcoholysis reaction product was 8638 kg / h, and the composition was 72.94 wt% methanol, 6.96 wt% methyl glycol, 16.6 wt% ethylene glycol, 2.29 wt% other diols, 0.36 wt% methyl acetate, 0.46 wt% high-boiling polymer, and 0.39 wt% heavy impurities.
[0047] The product from the fixed-bed alcoholysis reaction unit is fed into a fixed-bed alcoholysis separation unit (distillation column). Under conditions of a top temperature of 72.0°C, a bottom temperature of 211.0°C, a pressure of 135 kPa, 70 trays, and a top reflux ratio of 10, methanol with a mass flow rate of 300 kg / h and a purity of 96.0 wt% is collected from the top of the column as a light component. Methanol with a mass flow rate of 1000 kg / h and a purity of 99.8 wt% is collected from the side stream and returned to the fixed-bed alcoholysis reaction unit as a circulating methanol stream. The side stream, with a mass flow rate of 7000 kg / h, comprises, by weight, 71.63 wt% methanol, 8.6 wt% methyl glycolate, 16.82 wt% ethylene glycol, 1.97 wt% other diols, 0.24 wt% methyl acetate, 0.36 wt% high-boiling polymers, and 0.38 wt% heavy impurities. This liquid phase is used as the methyl glycol-, ethylene glycol-, and methanol-rich stream. The bottom stream, consisting of 338 kg / h of ethylene glycol and a heavy component fraction, comprises, by weight, 76.05 wt% ethylene glycol, 17.71 wt% other diols, 4.32 wt% high-boiling polymers, and 1.92 wt% heavy impurities (the other diols, high-boiling polymers, and heavy impurities are heavy components). The methyl glycol-, ethylene glycol-, and methanol-rich stream is returned to the separation unit of the original methyl glycolate production unit.
[0048] Comparative Example 1
[0049] The mass flow rate of the separation unit from the original methyl glycolate production unit was 2418 kg / h. The fusel oil, based on its total weight, consisted of 30.31 wt% other diols, 43.68 wt% ethylene glycol, 3 wt% heavy impurities, and 23.00 wt% high-boiling polymers. The fusel oil had a pH of 3.2. It was fed into the fixed-bed alcoholysis reaction unit (fixed-bed alcoholysis reactor) along with 4950 kg / h of methanol and a 1000 kg / h circulating methanol stream from the fixed-bed alcoholysis separation unit. The reaction was carried out at a temperature of 180°C, a pressure of 2 MPa, and a space velocity of 1 h⁻¹. -1 Under these conditions, the liquid-phase alcoholysis reaction product flow rate was 7368 kg / h, and the composition was 58.56 wt% methanol, 8.18 wt% methyl glycolate, 21.43 wt% ethylene glycol, 10.01 wt% other diols, 0.26 wt% methyl acetate, 0.3 wt% high-boiling polymer, and 1.26 wt% heavy impurities.
[0050] The product from the fixed-bed alcoholysis reaction unit is fed into a fixed-bed alcoholysis separation unit (distillation column). Under conditions of a top temperature of 71.0°C, a bottom temperature of 75.0°C, a pressure of 135 kPa, 70 trays, and a top reflux ratio of 60, methanol with a mass flow rate of 400 kg / h and a purity of 95.35 wt% is collected from the top of the column as a light component. Methanol with a mass flow rate of 1000 kg / h and a purity of 99.96 wt% is collected from the side stream and returned to the fixed-bed alcoholysis reaction unit as a circulating methanol stream. The mass flow rate of the bottom product from the tower is 5968 kg / h. Based on the total weight of the liquid phase, the composition is 49.15 wt% methanol, 10.1 wt% methyl glycol, 26.46 wt% ethylene glycol, 12.32 wt% other diols, 0.37 wt% high-boiling polymers, and 1.6 wt% heavy impurities. This liquid phase, rich in methyl glycol, ethylene glycol, methanol, and other diols, is sent to the separation unit of the original methyl glycol production unit to increase the production of methyl glycol and ethylene glycol.
[0051] Comparative Example 2
[0052] The mass flow rate of the separation unit from the original methyl glycolate production unit was 3988 kg / h. The fusel oil, based on its total weight, consisted of 21.31 wt% other diols, 62.59 wt% ethylene glycol, 2.1 wt% heavy impurities, and 14.00 wt% high-boiling polymers. The fusel oil had a pH of 3. It was fed into the fixed-bed alcoholysis reaction unit (fixed-bed alcoholysis reactor) along with 6950 kg / h of methanol and a 1000 kg / h circulating methanol stream from the fixed-bed alcoholysis separation unit. The reaction was carried out at a temperature of 180°C, a pressure of 2 MPa, and a space velocity of 1 h⁻¹. -1Under these conditions, the flow rate of the liquid-phase alcoholysis reaction product was 10938 kg / h, and the composition was 57.6 wt% methanol, 5.5 wt% methyl glycol, 27.62 wt% ethylene glycol, 7.8 wt% other diols, 0.25 wt% methyl acetate, 0.2 wt% high-boiling polymer, and 1.23 wt% heavy impurities.
[0053] The product from the fixed-bed alcoholysis reaction unit is fed into a fixed-bed alcoholysis separation unit (distillation column). Under conditions of a top temperature of 72.0°C, a bottom temperature of 75.0°C, a pressure of 135 kPa, 70 trays, and a top reflux ratio of 10, methanol with a mass flow rate of 400 kg / h and a purity of 97.6 wt% is collected from the top of the column as a light component. Methanol with a mass flow rate of 1000 kg / h and a purity of 99.89 wt% is collected from the side stream and returned to the fixed-bed alcoholysis reaction unit as a circulating methanol stream. The mass flow rate of the bottom product from the tower is 9538 kg / h. Based on the total weight of the liquid phase, the composition is 51.5 wt% methanol, 6.36 wt% methyl glycol, 31.68 wt% ethylene glycol, 8.96 wt% other glycols, 0.23 wt% high-boiling polymers, and 1.27 wt% heavy impurities. This liquid phase, rich in methyl glycol, ethylene glycol, methanol, and other glycols, is sent to the separation unit of the original methyl glycol production unit to increase the production of methyl glycol and ethylene glycol.
[0054] The light component stream can remove low-boiling-point esters (methyl acetate) from the alcoholysis products. These substances can affect the selectivity of the fusel oil alcoholysis reaction. The heavy component stream can remove heavy impurities generated during the alcoholysis reaction and / or contained in the separation unit of the original methyl glycolate production unit, preventing the accumulation of impurities in the system. The heavy component stream can also remove other diol components besides ethylene glycol, reducing their accumulation in the cycle and thus reducing unit energy consumption. In Example 1, the circulating methanol stream has a large output, allowing a large amount of methanol to be separated in the downstream fixed-bed alcoholysis separation unit. In Example 2, the circulating methanol stream has a small output, allowing a large amount of methanol to return to the upstream original methyl glycolate production unit separation unit along with the methyl glycolate-rich, ethylene glycol, and methanol streams for separation. The total methanol circulation volume can be adjusted between the two paths, enhancing the unit's adjustment flexibility to meet the load limitations of the original methyl glycolate production unit separation unit. This allows the fixed-bed alcoholysis technology to be better integrated into the original production unit, thereby solving the fusel oil treatment problem in situ in the oxalate ester route. Meanwhile, in Example 2, the small circulating methanol stream leads to a large amount of methyl glycolate, ethylene glycol and methanol side streams being extracted, making it difficult to extract the heavy components. Compared with Example 1, this results in a higher ethylene glycol content in the ethylene glycol and heavy component streams, and increased ethylene glycol loss.
[0055] In Comparative Examples 1 and 2, no ethylene glycol or recombinant fraction was extracted (it returned to the upstream original methyl glycolate production unit separation unit along with the methyl glycolate, ethylene glycol and methanol fractions), which resulted in other diols besides ethylene glycol not being separated in time during the cycle, leading to an increase in the amount of liquid phase products returning upstream and an increase in the energy consumption of the entire unit.
[0056] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A method for recycling fusel oil fixed-bed alcoholysis products, characterized in that, The method includes: (1) Fusel oil and methanol from the separation unit of the original methyl glycolate production unit are fed into the fixed-bed alcoholysis reaction unit. (2) The product of the fixed-bed alcoholysis reaction unit is fed into the fixed-bed alcoholysis separation unit, and the light component, the circulating methanol stream, the methyl glycol-rich, ethylene glycol and methanol stream, and the ethylene glycol and recombinant fraction are separated by the fixed-bed alcoholysis separation unit. (3) The circulating methanol stream is returned to the fixed-bed alcoholysis reaction unit, and the methyl glycolate, ethylene glycol and methanol stream is returned to the separation unit of the original methyl glycolate production unit; preferably, the content of the residual heavy components in the methyl glycolate, ethylene glycol and methanol stream is less than 5 wt% based on the total weight of the methyl glycolate, ethylene glycol and methanol stream.
2. The method according to claim 1, wherein, The fusel oil includes: small molecule compounds, high-boiling polymers, and optional heavy impurities; The small molecule compounds include: ethylene glycol, optionally glycolic acid, optionally methyl glycolate, and optionally other diols; The high-boiling polymer is a polymer generated by polymerization of at least one of ethylene glycol, glycolic acid, and methyl glycolate. Preferably, the pH value of the fusel oil is 2-6.
3. The method according to claim 2, wherein, The content of high-boiling polymers is not less than 5 wt%, preferably 10-80 wt%, based on the total weight of the fusel oil; The content of ethylene glycol is 15-80 wt%, the content of methyl glycolate is 0-30 wt%, the content of glycolic acid is 0-10 wt%, the content of other diols is 0-40 wt%, and the content of heavy impurities is 0-5 wt%.
4. The method according to claim 1, wherein, The fixed-bed alcoholysis separation unit employs atmospheric distillation or vacuum distillation as the separation method. Preferably, the atmospheric distillation is carried out under conditions of 101-201 kPa and 60-240°C; the vacuum distillation is carried out under conditions of 5 Pa-100 kPa and 40-220°C.
5. The method according to claim 1, wherein, Based on the total weight of the light components, the methanol content in the light components is <99 wt%; Based on the total weight of the circulating methanol stream, the content of circulating methanol in the circulating methanol stream is ≥99wt%.
6. The method according to claim 1, wherein, The amount of recycled methanol in the recycled methanol stream accounts for 10-95 wt% of the methanol content in the reaction product of the fixed-bed alcoholysis reaction unit, preferably 20-95 wt%, and more preferably 40-90 wt%.
7. The method according to claim 1, wherein, The fixed-bed alcoholysis reaction unit is a fixed-bed alcoholysis reactor.
8. The method according to claim 1, wherein, In the fixed-bed alcoholysis reaction unit, the reaction pressure is 0.1-4 MPa; The reaction temperature is 80-250℃.
9. The method according to claim 1, wherein, In the fixed-bed alcoholysis reaction unit, the space velocity of the reaction is 0.5-5 h⁻¹. -1 .
10. The method according to claim 1, wherein, The catalyst used in the fixed-bed alcoholysis reaction unit is a metal oxide catalyst, preferably a zinc oxide catalyst and / or a copper oxide catalyst, and more preferably a zinc oxide catalyst.