PROCESS FOR REFINING ETHYLENE GLYCOL NOT DERIVED FROM PETROLEUM

Abstract

The invention provides a process for refining non-petroleum ethylene glycol, in which impurities with a boiling point close to that of ethylene glycol are removed. In the process, C5-C20 oleophilic alcohol compounds, C5-C20 alkanes, and / or C4-C20 oleophilic ketone compounds are azeotropically treated with non-petroleum ethylene glycol to produce an ethylene glycol-containing azeotrope. The azeotropic agent is then separated and removed from the azeotrope to obtain a crude ethylene glycol product, which is further purified to yield ethylene glycol.

Description

PROCESS FOR REFINING ETHYLENE GLYCOL NOT DERIVED FROM PETROLEUM FIELD OF INVENTION The invention relates to a process for refining ethylene glycol. In particular, it relates to a process for refining non-petroleum-derived ethylene glycol comprising impurities including butanediol, pentanediol, hexanediol, and optionally, etc., having a boiling point close to that of ethylene glycol, and impurities including traces of acids, ethers, aldehydes, ketones, and / or alcohols, etc., that affect the ultraviolet transmittance of ethylene glycol. BACKGROUND OF THE INVENTION In recent years, non-petroleum-based technologies, such as ethylene glycol production from coal and biomass feedstocks, have developed rapidly due to oil price uncertainty and increased focus on sustainable development. However, due to differences in the synthetic pathways, ethylene glycol production using non-petroleum-based methods produces different byproducts than those from petroleum-based methods. These byproducts include alcohol impurities such as butanediol, pentanediol, hexanediol, and similar compounds, as well as trace amounts of acids, ethers, aldehydes, ketones, and / or alcohols, all of which affect the ultraviolet transmittance of ethylene glycol. These impurities may be present in quantities below the detection limit of gas chromatography.A traditional method for purifying liquid-phase compounds is rectification, which separates substances based on their different boiling points. However, the boiling points of these impurities are close to that of ethylene glycol. For example, alcohol impurities such as butanediol, hexanediol, pentanediol, and similar substances, as well as impurities containing traces or even amounts below the gas chromatography detection limit of acids, ethers, aldehydes, ketones, and / or alcohols, etc., which affect the ultraviolet transmittance of ethylene glycol, have physical properties similar to ethylene glycol and boiling points very close to it. Therefore, separating ethylene glycol from alcohol impurities by direct rectification would lead to a low distillation yield of ethylene glycol and high energy consumption.Furthermore, the ultraviolet transmittance of ethylene glycol obtained by rectification cannot directly meet the requirements of fiber-grade and bottle-grade polyesters, as it still contains some traces of impurities. The documents US4935102, US4966658, US5423955 and US8906205 describe QFQZnn / ί7P7 / E / YILI technologies for separating ethylene glycol from butanediol using different azeotropic agents. An azeotropic agent has an azeotropic point with ethylene glycol. Generally, the temperature of an azeotropic point is apparently lower than the boiling point of ethylene glycol. Therefore, a distinct temperature difference occurs between the boiling point of an ethylene glycol azeotrope and an azeotropic agent and that of impurities such as butanediol. The separation of ethylene glycol and butanediol can be achieved economically by rectification. The production of ethylene glycol using non-petroleum-derived methods will produce alcohol impurities in addition to ethylene glycol, such as pentanediol and hexanediol, which have boiling points very close to that of ethylene glycol, and impurities including traces, or even amounts below the gas chromatography detection limit, of acids, ethers, aldehydes, ketones, and / or alcohols that affect the ultraviolet transmittance of ethylene glycol. However, the literature mentioned above only describes the effects of separating ethylene glycol from butanediol using an azeotropic agent, without mentioning the effects of separating ethylene glycol from pentanediol, hexanediol, etc., after using an azeotropic agent.Nor do they mention the effects of separating ethylene glycol from traces or even quantities below the gas chromatography detection limit of impurities such as acids, ethers, aldehydes, ketones, and / or alcohols that affect the ultraviolet transmittance of ethylene glycol. Therefore, these patents do not mention that the ultraviolet transmittance of ethylene glycol can be improved. CN106946654A describes an adsorption bed with porous carbon adsorbents for adsorbing impurities from biomass-derived ethylene glycol to achieve ethylene glycol refining effects. This technique only describes the improvement of the ultraviolet transmittance of ethylene glycol, but does not describe its ability to separate butanediol (a compound with the following molecular formula), pentanediol, hexanediol, and other alcohol impurities. BRIEF DESCRIPTION OF THE INVENTION The invention provides a process for refining non-petroleum-derived ethylene glycol, in which impurities with a boiling point close to that of ethylene glycol are separated. The process can increase the purity of said ethylene glycol to 99.90% or more, preferably 99.95% or more, under conditions of a high ethylene glycol recovery rate of 95% or more, preferably 97% or more, and particularly preferably 98% or more. Furthermore, the ultraviolet transmissions of ethylene glycol obtained at wavelengths of 220 nm, 275 nm, and 350 nm are improved to 75% or more, 92% or more, and 99% or more, respectively. QFQZnn / ίZΠZ / Β / YΙΛΙ The term "non-petroleum ethylene glycol" refers to ethylene glycol produced by non-petroleum means, particularly ethylene glycol produced from coal or biomass. It comprises, but is not limited to, ethylene glycol, butanediol, pentanediol, and hexanediol. Preferably, the non-petroleum ethylene glycol further comprises a compound having the following molecular formula: [formula missing in original text]. The butanediol is preferably 1,2-butanediol, the pentanediol is preferably 1,2-pentanediol, and the hexanediol is preferably 1,2-hexanediol. In the process of the invention, one, two, or more C5-C20 oleophilic alcohol compounds, C5-C20 alkanes, and C4-C20 oleophilic ketone compounds are subjected to azeotropy as an azeotropic agent together with non-petroleum-derived ethylene glycol to obtain an ethylene glycol-containing azeotrope. Water is then added to dissolve the ethylene glycol in the azeotrope. The water-insoluble azeotropic agent is separated from the aqueous ethylene glycol solution, and the ethylene glycol is obtained by dehydration and refining of the resulting aqueous ethylene glycol solution. In one embodiment of the invention, the C5-C20 oleophilic alcohol compounds are preferably C6-C15 oleophilic alcohol compounds, more preferably C7-C12 oleophilic alcohol compounds, and particularly preferably C7-C10 oleophilic alcohol compounds. The oleophilic alcohol compounds may be aliphatic alcohols and alcohols containing heterocycles. Examples of oleophilic alcohol compounds include pentanol and its isomers, hexanol and its isomers, heptanol and its isomers, octanol and its isomers, nonanol and its isomers, decanol and its isomers, undecanol and its isomers, lauryl alcohol and its isomers, and benzyl alcohol. Most preferably, these oleophilic alcohol compounds are heptanol, isoheptanol, octanol, isooctanol, nonanol, isononanol, decanol, and isodecanol. In another embodiment of the invention, the C5-C20 alkanes are preferably C5-C15 alkanes, preferably C5-C12 alkanes, and particularly preferably C5-C10 alkanes. The alkanes may be straight-chain alkanes, branched alkanes, cycloalkanes, or alkanes containing a benzene ring. Examples of alkanes are pentane and its isomers, hexane and its isomers, heptane and its isomers, octane and its isomers, nonane and its isomers, decane and its isomers, undecane and its isomers, dodecane and its isomers, cyclopentane and cyclohexane, and ethylbenzene and its isomers. Most preferably, the alkanes are hexane, heptane, octane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, and ethylbenzene. In another embodiment of the invention, said C4-C20 oleophilic ketone compounds are preferably C5-C15 oleophilic ketone compounds, more preferably C6-C12 oleophilic ketone compounds, particularly preferably Ce oleophilic ketone compounds QFQZnn / ίZΠZ / Β / YΙΛΙ Cío. Ketones can be aliphatic ketones or alicyclic ketones. Especially preferred ketones are heptanone, diisobutyl ketone, cyclohexanone, and 2-nonanone. The biomass according to the invention preferably refers to first-generation edible biomass, including corn, sugarcane, etc., and second-generation non-food biomass from agricultural and forestry waste, including straw, wood, bagasse, etc. Preferably, the non-petroleum ethylene glycol of the invention comprises, but is not limited to, ethylene glycol, butanediol (preferably 1,2-butanediol), pentanediol (preferably 1,2-pentanediol), hexanediol (preferably 1,2-hexanediol), and propylene glycol, glycerol, and / or sorbitol. More preferably, said non-petroleum ethylene glycol comprises, but is not limited to: 1-100% by weight of ethylene glycol (excluding the 100% by weight endpoint), preferably 1-99% by weight of ethylene glycol, more preferably 5-99% by weight of ethylene glycol and particularly preferably 10-95% by weight of ethylene glycol; 0-95% by weight, preferably 0-50% by weight, more preferably 0-30% by weight, particularly preferably 0-10% by weight of butanediol (preferably 1,2-butanediol, excluding the 0 endpoint); 0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of pentanediol (preferably 1,2-pentanediol, excluding the 0 endpoint); 0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of hexanediol (preferably 1,2-hexanediol, excluding the 0 endpoint), and optionally 0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of Said non-petroleum-derived ethylene glycol also optionally comprises: 0-95% by weight, preferably 0.1-50% by weight of 1,2-propanediol, 0-50% by weight, preferably 0.01-10% by weight of 2,3-butanediol, 0-20% by weight, preferably 0.01-10% by weight of glycerol, and / or 0-20% by weight, preferably 0.01-10% by weight of sorbitol. In the process of the invention, the azeotropic agent forms an azeotrope by azeotropism with ethylene glycol. There is a clear temperature difference between the boiling point of the azeotrope and that of impurities such as butanediol, pentanediol, hexanediol, and traces of other acids, ethers, aldehydes, ketones, and / or alcohols, etc. QFQZnn / įZРZ / В / YILI affect ultraviolet transmittance. Therefore, ethylene glycol can be purified economically, for example, by a rectification process. The azeotropic agent can be separated from an aqueous solution containing ethylene glycol by an extraction process after mixing the azeotrope with water. This aqueous solution containing ethylene glycol is then refined after dehydration to obtain ethylene glycol. BRIEF DESCRIPTION OF THE FIGURES Figure I is a flow diagram of the azeotropic refining process of non-petroleum-derived ethylene glycol of the invention. Figure 2 is a flow diagram of the traditional rectification process of non-petroleum-derived ethylene glycol. DETAILED DESCRIPTION OF THE INVENTION In combination with Figure 1, the refinement process of the invention is described as follows: A mixed alcohol feed and an azeotropic agent feed are mixed before entering the azeotropic tower, which is a rectification tower. The weight ratio of the azeotropic agent feed to ethylene glycol in the mixed alcohol feed is 0.1:1–20:1, preferably 0.2:1–10:1, and more preferably 0.5:1–10:1. The operating pressure of the azeotropic tower is 1 kPa (absolute) - 101 kPa (absolute), and the weight ratio of the reflux material to the material extracted in the azeotropic tower (i.e., reflux ratio) is 0.1:1-15:1. There, most of the ethylene glycol and a small amount of other impurities in the mixed alcohol feed are extracted from the top of the azeotropic tower along with the azeotropic agent (i.e., stream 1) and enter a phase separator for products from the top of the azeotropic tower.Impurities from heavy components including, but not limited to, butanediol, pentanediol, hexanediol and, optionally, , and a small amount of azeotropic agent are extracted from the bottom of the azeotropic tower (i.e., stream 8) and enter the evaporator. Stream 1 and fresh water, and optionally recycled water (i.e., stream 4), are mixed and stratified in the phase separator for products from the top of the azeotropic tower. A layer of azeotropic agent (i.e., stream 2) is recycled to the azeotropic tower, while the water layer (i.e., stream 3) enters a dewatering tower for products from the top of the azeotropic tower. In the dewatering tower for products from the top of the azeotropic tower, the water in stream 3 is extracted from the top of the tower (i.e., stream 4) and recycled to the phase separator for the products from the top of the tower QFQZnn / Lznz / E / YILI azeotropic. Ethylene glycol containing light component impurities (i.e., stream 5) is drawn off via the side line and enters the ethylene glycol refinery tower. Heavy component impurities (i.e., stream 6) at the bottom of the tower are discharged from the system. Stream 5 is refined to purify ethylene glycol in the ethylene glycol refinery tower, and the ethylene glycol is extracted from the side line of the tower. Both the purity and ultraviolet transmittance of the resulting ethylene glycol product meet the requirements for fiber-grade and bottle-grade polyesters. Other impurities from the lighter components are extracted from the top of the ethylene glycol refinery tower. Impurities from the heavier components are extracted from the bottom of the ethylene glycol refinery tower. The materials at the bottom of the azeotropic tower (i.e., stream 8) enter the evaporator, where impurities of heavy components that have an extremely high boiling point, such as glycerol and sorbitol, are separated from the bottom of the evaporator and discharged from the system (i.e., stream 9). Stream 10, comprising, but not limited to, an azeotropic agent, butanediol, pentanediol, hexanediol, and optionally, enters the phase separator for bottom products from the azeotropic tower, and is then mixed with fresh water and optionally recycled water (i.e., stream 13), and then stratified. There, the azeotropic agent layer (i.e., stream 11) is recycled to the azeotropic tower, while the water layer (i.e., stream 12), comprising, but not limited to, water, butanediol, pentanediol, and hexanediol, enters the dewatering tower for bottom products from the azeotropic tower for dehydration. The water in the water layer (i.e., stream 12) of the phase separator for bottom products of the azeotropic tower is separated in the dewatering tower for bottom products of the azeotropic tower, extracted from the top of the tower (i.e., stream 13), and then recycled to the phase separator for bottom products of the azeotropic tower. Impurities comprising, but not limited to, butanediol, pentanediol, and hexanediol are extracted from the bottom of the dewatering tower for bottom products of the azeotropic tower and discharged from the system. The technology of the invention can separate ethylene glycol from impurities comprising, but not limited to, butanediol, pentene glycol, hexanediol, and optionally, under the condition of a high ethylene glycol recovery rate of 95% or more, preferably 97% or more, and particularly preferably 98% or more. Meanwhile, the purity of the ethylene glycol is improved to 99.90% or more, preferably 99.95% or more, and the ultraviolet transmissions of the obtained ethylene glycol are improved to 75% or more, 92% or more, and 99% or more at wavelengths of 220 nm, 275 nm, and 350 nm, respectively. Therefore, the problem that the separation of impurities such as butanediol, pentanediol, hexanediol and, optionally, cannot be achieved simultaneously with the improvement of ultraviolet transmittance in the technology of the previous technique of purification of non-petroleum-derived ethylene glycol is solved. Examples The present invention is further described by the following examples. However, the present invention is not limited to them. Example 1 According to the flow diagram illustrated in Figure 1, the mixed alcohol feed was the material obtained from the dehydration and removal of light components from the mixed product produced from the biomass feedstock. The material consisted of, by weight percentage, 85.1% ethylene glycol, 6.6% 1,2-propanediol, 2.2% 1,2-butanediol, 0.4% 2,3-butanediol, 0.7% 1,4-butanediol, 0.2% 1,2-pentanediol, 0.2% 1,2-hexanediol, 0.1% [unspecified], 0.5% glycerol, 0.5% sorbitol, and 3.5% other light and heavy components. The mixed alcohol feed and the fresh azeotropic agent isoectanol were mixed and entered the 45th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including the fresh and recycled azeotropic agent, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 3.39:1. There were a total of 90 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 40th theoretical plate, respectively. The operating pressure of the azeotropic tower was 50 kPa (absolute), and the reflux ratio was 0.5:1.Stream 1 from the upper tower separated by the azeotropic tower was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, and other light components, respectively in weight percent of 74.97%, 22.18%, 2.54%, 0.11%, 0.08%, 0%, 0%, 0%, 0% and 0.12%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for products from the bottom of the azeotropic tower entered the phase separator for products from the QFQZnn / ίZРZ / B / YILI bottom of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11) which was a recycled azeotropic agent was recycled to the azeotropic tower; the water layer (i.e., stream 12) which was a mixture of alcohol and water entered the dehydration tower for products from the bottom of the azeotropic tower for dehydration, and the water (i.e., stream 13) was recycled to the phase separator for products from the bottom of the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the water layer stream (i.e., stream 3) entered the dewatering tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from sideline 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 20:1 and an operating pressure of 10 kPa (absolute). The ethylene glycol product was extracted from the 80th theoretical plate of the ethylene glycol refinery tower.When analyzed using the methods of the national standards GB / T4649-2008 and the US standards ASTM E2409 and ASTM E2139, the purity of the refined ethylene glycol was 99.96% by weight, and the ultraviolet transmissions were 83.2% at a wavelength of 220 nm, 96.0% at a wavelength of 275 nm, and 99.0% at a wavelength of 350 nm, respectively. The overall ethylene glycol rectification yield was 98.2%. Example 2 According to the flow diagram illustrated in Figure 1, the mixed alcohol feed was the material obtained from the dehydration and removal of light components from the mixed product produced from the biomass feedstock. The material was composed, by weight percentage, of 23.2% ethylene glycol, 55.09% 1,2-propanediol, 4.60% 1,2-butanediol, 1.40% 2,3-butanediol, 0.60% 1,4-butanediol, 0.31% 1,2-pentanediol, 0.49% 1,2-hexanediol, 0.15% glycerol, 10% sorbitol, and 10.16% other light and heavy components. The mixed alcohol feed and the new 2-nonanone azeotropic agent were mixed and fed into the 30th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including the new and recycled azeotropic agents, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 7.04:1. There were a total of 90 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 25th theoretical plate, respectively. The operating pressure of the azeotropic tower was 30 kPa (absolute), and the reflux ratio was 2.5:1.Stream 1 from the upper tower, separated by the azeotropic tower, was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, and other light components, respectively in weight percentages of 64.96%, 9.23%, 24.98%, 0.20%, 0.32%, 0%, 0%, 0%, 0%, and 0.31%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for products from the bottom of the azeotropic tower entered the phase separator for products from the bottom of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11), which was recycled azeotropic agent, was recycled to the azeotropic tower; the water layer (i.e., stream 12), which was a mixture of alcohol and water, entered the dewatering tower for products from the bottom of the azeotropic tower for dewatering; and the water (i.e., stream 13) was recycled to the phase separator for products from the bottom of the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the water layer stream (i.e., stream 3) entered the dewatering tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from sideline 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 20:1 and an operating pressure of 10 kPa (absolute). The ethylene glycol product was extracted from the 80th theoretical plate of the ethylene glycol refinery tower.When analyzed using the methods of the national standards GB / T4649-2008 and the US standards ASTM E2409 and ASTM E2139, the purity of the refined ethylene glycol was 99.95% by weight, and the ultraviolet transmissions were 76.1% at a wavelength of 220 nm, 95.5% at a wavelength of 275 nm, and 99.0% at a wavelength of 350 nm, respectively. The overall ethylene glycol rectification yield was 98.8%. Example 3. According to the flow diagram illustrated in Figure 1, the mixed alcohol feed was the material obtained from the dehydration and removal of light components from the mixed product produced from the biomass feedstock. The material consisted of, by weight percentage, 92.50% ethylene glycol, 4.89% 1,2-propanediol, QFQZnn / ίZΠZ / Β / YΙΛΙ 1.42% of 1,2-butanediol, 0.17% of 2,3-butanediol, 0.12% of 1,4-butanediol, 0.06% of 1,2-pentanediol, 0.24% of 1,2-hexanediol, 0.07% of, and 0.53% of other light and heavy components. The mixed alcohol feed and the new azeotropic agent n-decanol were mixed and entered the 30th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including the new and recycled azeotropic agent, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 0.60:1. There were a total of 90 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 25th theoretical plate, respectively. The operating pressure of the azeotropic tower was 20 kPa (absolute), and the reflux ratio was 3:1. Stream 1 of the upper tower separated by the azeotropic tower was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol.1,2-hexanediol and other light components, respectively in weight percentages of 35.81%, 60.45%, 3.15%, 0.44%, 0.02%, 0%, 0%, 0%, 0%, 0.13%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for products from the bottom of the azeotropic tower entered the phase separator for products from the bottom of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11), which was recycled azeotropic agent, was recycled to the azeotropic tower; the water layer (i.e., stream 12), which was a mixture of alcohol and water, entered the dewatering tower for products from the bottom of the azeotropic tower for dewatering; and the water (i.e., stream 13) was recycled to the phase separator for products from the bottom of the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the water layer stream (i.e., stream 3) entered the dewatering tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from sideline 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 40:1 and an operating pressure of 20 kPa (absolute). The product of Ethylene glycol was extracted from the 80th theoretical plate of the ethylene glycol refinery tower. Analyzed using the methods of the national standards GB / T4649-2008 and the US standards ASTM E2409 and ASTM E2139, the purity of the refined ethylene glycol was 99.96% by weight, and the ultraviolet transmissions were 76.0% at a wavelength of 220 nm, 95.4% at a wavelength of 275 nm, and 99.0% at a wavelength of 350 nm. The overall ethylene glycol rectification yield was 96.5%. Example 4 According to the process illustrated in Figure 1, the mixed alcohol feed was the same as the mixed alcohol feed in Example 3. The mixed alcohol feed and the new azeotropic agent 2-heptanol were mixed and fed into the 30th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including the new and recycled azeotropic agent, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 8.35:1. There were a total of 90 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 25th theoretical plate, respectively. The operating pressure of the azeotropic tower was 50 kPa (absolute), and the reflux ratio was 3:1. Stream 1 of the upper tower separated by the azeotropic tower was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol.1,2-hexanediol and other light components, respectively in weight percentage of 88.15%, 11.21%, 0.55%, 0%, 0%, 0%, 0%, 0%, 0%, 0.09%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for bottom products of the azeotropic tower entered the phase separator for bottom products of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11), which was a recycled azeotropic agent, was recycled to the azeotropic tower; the water layer (i.e., stream 12), which was a mixture of alcohol and water, entered the dewatering tower for bottom products of the azeotropic tower for dewatering; and the water (i.e., stream 13) was recycled to the phase separator for bottom products of the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the stream from the layer of The QFQZnn / ίZРZ / B / YILI water (i.e., stream 3) entered the dehydration tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from side line 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 20:1 and an operating pressure of 20 kPa (absolute). The ethylene glycol product was extracted from the 80th theoretical plate of the ethylene glycol refinery tower. When analyzed respectively through the method of the national standards GB / T4649-2008 and ASTM E2409 and ASTM E2139 of the USA, the purity of the refined ethylene glycol in weight percent was 99.96%, and the ultraviolet transmissions were 76.6% at a wavelength of 220 nm, 92.1% at a wavelength of 275 nm and 99.5% at a wavelength of 350 nm, respectively.The overall rectification yield of ethylene glycol was 97.0%. Example 5 According to the process illustrated in Figure 1, the mixed alcohol feed was the same as the mixed alcohol feed in Example 3. The mixed alcohol feed and the new n-octane azeotropic agent were mixed and entered the 30th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including the new and recycled azeotropic agents, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 9.1:1. There were a total of 63 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 25th theoretical plate, respectively. The operating pressure of the azeotropic tower was 101 kPa (absolute), and the reflux ratio was 5:1. Stream 1 of the upper tower, separated by the azeotropic tower, was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol and other light components, respectively in weight percentages of 89.55%, 9.86%, 0.51%, 0.01%, 0.01%, 0%, 0%, 0%, 0%, 0.06%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for products from the bottom of the azeotropic tower entered the phase separator for products from the bottom of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11), which was recycled azeotropic agent, was recycled to the azeotropic tower; the water layer (i.e., stream 12), which was a mixture of alcohol and water, entered the dewatering tower for products from the bottom of the azeotropic tower for dewatering; and the water (i.e., stream 13) was recycled to the phase separator for products from the bottom of the azeotropic tower. QFQZnn / ίΖΠΖ / Β / ΥΙΛΙ the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the water layer stream (i.e., stream 3) entered the dewatering tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from sideline 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 40:1 and an operating pressure of 20 kPa (absolute). The ethylene glycol product was extracted from the 80th theoretical plate of the ethylene glycol refinery tower.When analyzed using the methods of the national standards GB / T4649-2008 and the US standards ASTM E2409 and ASTM E2139, the purity of the refined ethylene glycol was 99.96% by weight, and the ultraviolet transmissions were 75.3% at a wavelength of 220 nm, 93.0% at a wavelength of 275 nm, and 99.2% at a wavelength of 350 nm, respectively. The overall ethylene glycol rectification yield was 97.1%. Example 6 According to the process illustrated in Figure 1, the mixed alcohol feed was a blended product produced from coal as a raw material. The material consisted of, by weight percentage, 77.94% ethylene glycol, 0.86% 1,2-propanediol, 17.15% 1,2-butanediol, 0.60% 2,3-butanediol, 0.01% 1,4-butanediol, 0.02% 1,2-pentanediol, 0.01% 1,2-hexanediol, and 3.41% other light and heavy components. The mixed alcohol feed and fresh isoectanol from the azeotropic agent were mixed and entered the 30th theoretical plate of the azeotropic tower. The weight ratio of the azeotropic agent (including fresh and recycled azeotropic agent, streams 2 and 11) to ethylene glycol in the mixed alcohol feed was 3.26:1. There were a total of 90 theoretical plates in the azeotropic tower. Stream 2 of recycled azeotropic agent from the top of the tower and stream 11 of recycled azeotropic agent from the bottom of the tower entered the azeotropic tower from the 25th theoretical plate, respectively. The operating pressure of the azeotropic tower was 77 kPa (absolute), and the reflux ratio was 2:1.Stream 1 from the upper tower separated by the azeotropic tower was composed of an azeotropic agent, ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol and other light components, respectively in weight percent of 76.07%, 23.35%, 0.15%, 0.03%, 0.23%, 0%, 0%, 0%, 0.17%. Stream 9 of heavy components that have a high boiling point was separated from stream 8 by an evaporator. Streams 10 and 13 from the top of the dewatering tower for products from the bottom of the azeotropic tower entered the phase separator for products from the bottom of the azeotropic tower. The layer of stratified azeotropic agent (i.e., stream 11), which was recycled azeotropic agent, was recycled to the azeotropic tower; the water layer (i.e., stream 12), which was a mixture of alcohol and water, entered the dewatering tower for products from the bottom of the azeotropic tower for dewatering; and the water (i.e., stream 13) was recycled to the phase separator for products from the bottom of the azeotropic tower. Stream 1 from the top of the azeotropic tower, along with stream 4 from the top of the dewatering tower for products from the top of the azeotropic tower, entered the phase separator for products from the top of the azeotropic tower. After separation by the phase separator, the water layer stream (i.e., stream 3) entered the dewatering tower for products from the top of the azeotropic tower for dehydration. After dehydration, the stream from sideline 5 entered the 60th theoretical plate of the ethylene glycol refinery tower. The ethylene glycol refinery tower had a total of 90 theoretical plates with a reflux ratio of 20:1 and an operating pressure of 20 kPa (absolute). The ethylene glycol product was extracted from the 80th theoretical plate of the ethylene glycol refinery tower.When analyzed using the methods of the national standards GB / T4649-2008 and the US standards ASTM E2409 and ASTM E2139, the purity of the refined ethylene glycol was 99.98% by weight, and the ultraviolet transmissions were 77.1% at a wavelength of 220 nm, 95.0% at a wavelength of 275 nm, and 99.2% at a wavelength of 350 nm. The overall ethylene glycol rectification yield was 98.5%. Comparative Example 1 The material obtained from the dehydration and removal of light components from the mixed product produced from the blomass feedstock in Example 1 was used as the feedstock for the mixed alcohol. The separation was carried out using the traditional rectification method, as illustrated in Figure 2. Since no azeotropic agent was added in the traditional rectification process, and no extraction section was required, there was no need for a phase separator for top-of-the-tower products, a phase separator for bottom-of-the-tower products, a dehydration tower for top-of-the-tower products, a dehydration tower for bottom-of-the-tower products, or an evaporator.In comparison with Example 1, the total theoretical plates and operating conditions of the tower for removing heavy components in ethylene glycol were the same as those of the azeotropic tower; the total theoretical plates and the. QFQZnn / Lznz / E / YILI The operating conditions of the tower for removing light components in ethylene glycol in Comparative Example 1 were the same as those of the ethylene glycol refinery tower of Example 1. The ethylene glycol product consisted of ethylene glycol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol and 1,2-hexanediol and in weight percent of 99.45%, 0%, 0.25%, 0%, 0%, 0.02%, 0.21% and 0.07%, respectively. The ultraviolet transmissions were 56.1% at a wavelength of 220 nm, 87.2% at a wavelength of 275 nm, and 96.8% at a wavelength of 350 nm. The overall rectification yield of low-purity ethylene glycol was 93.0%. Experimental results show that traditional rectification without an azeotropic agent cannot effectively separate impurities from 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol and optionally etc. in ethylene glycol. An increased reflux ratio and higher energy consumption are required to achieve a purity of 99.9%. Furthermore, the ultraviolet transmittance cannot be effectively improved. The process of the invention can effectively increase the purity of said ethylene glycol to 99.90% or more, under the condition of high ethylene glycol yield. In addition, the ultraviolet transmittance of the obtained ethylene glycol at wavelengths of 220 nm, 275 nm, and 350 nm can be increased to 75% or more, 92% or more, and 99% or more, respectively.

Claims

1. A process for retinning a non-petroleum-derived ethylene glycol, wherein one, two, or more C5-C20 oleophilic alcohol compounds, C5-C20 alkanes, and C4-C20 oleophilic ketone compounds are azeotropically treated together with the non-petroleum-derived ethylene glycol to obtain an ethylene glycol-containing azeotrope, water is then added to dissolve the ethylene glycol in the azeotrope, the water-insoluble azeotropic agent is separated from the aqueous ethylene glycol solution, and ethylene glycol is obtained from the dehydration and refining of the resulting aqueous ethylene glycol solution, wherein the non-petroleum-derived ethylene glycol comprises, but is not limited to, ethylene glycol, butanediol (preferably 1,2-butanediol), pentanediol (preferably 1,2-pentanediol), and hexanediol (preferably 1,2-hexanediol).

2. A process according to claim 1, wherein the C5-C20 oleophilic alcohol compounds are Ce-Ois oleophilic alcohol compounds, preferably C7-C12 oleophilic alcohol compounds and particularly preferably C7-C10 oleophilic alcohol compounds, and the oleophilic alcohol compounds can be aliphatic alcohols and alcohols containing heterocycles, for example, pentanol and its isomers, hexanol and its isomers, heptanol and its isomers, octanol and its isomers, nonanol and its isomers, decanol and its isomers, undecanol and its isomers, lauryl alcohol and its isomers, and benzyl alcohol.

3. Process according to claim 2, wherein the C5-C20 oleophilic alcohol compounds are hexanol, isohexanol, heptanol, isoheptanol, octanol, isooctanol, nonanol, isononanol, decanol and isodecanol.

4. A process according to any one of claims 1 to 3, wherein the C5-C20 alkanes are C5-C15 alkanes, preferably C5-C12 alkanes and particularly preferably C5-C10 alkanes, and the alkanes can be straight-chain alkanes, branched alkanes, cycloalkanes or alkanes containing benzene rings, for example, pentane and its isomers, hexane and its isomers, heptane and its isomers, octane and its isomers, nonane and its isomers, decane and its isomers, undecane and its isomers, dodecane and its isomers, cyclopentane, cyclohexane, ethylbenzene and its isomers, preferably hexane, heptane, octane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, ethylbenzene.

5. Process according to any of claims 1 to 4, wherein the C4-C20 oleophilic ketone compounds are C5-C15 oleophilic ketone compounds, preferably C6-C12 oleophilic ketone compounds and particularly preferably Ce-Cio oleophilic ketone compounds, and the ketones can be aliphatic ketones or alicyclic ketones, preferably heptanone, diisobutyl ketone, cyclohexanones, 2-nonone.

6. A process according to any one of claims 1 to 5, wherein the non-petroleum ethylene glycol is ethylene glycol produced from coal or ethylene glycol produced from biomass, wherein the biomass preferably refers to first-generation edible biomass including corn, sugar cane, etc., and second-generation non-food biomass from agricultural and forestry wastes including straw, wood, bagasse, etc.

7. Process according to any of claims 1 to 6, wherein the non-petroleum-derived ethylene glycol further comprises ° 8. Process according to any of claims 1 to 7, wherein the non-petroleum-derived ethylene glycol comprises propylene glycol, glycerol and / or sorbitol.

9. A process according to any one of claims 1 to 8, wherein said non-petroleum ethylene glycol comprises: 1-100% by weight of ethylene glycol, excluding the 100% by weight endpoint, preferably 1-99% by weight of ethylene glycol, more preferably 5-99% by weight of ethylene glycol and particularly preferably 10-95% by weight of ethylene glycol; 0-95% by weight, preferably 0-50% by weight, more preferably 0-30% by weight, particularly preferably 0-10% by weight of butanediol, preferably 1,2-butanediol, excluding the 0% endpoint; 0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of pentanediol, preferably 1,2-pentanediol, excluding the 0% endpoint; 0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of hexanediol, preferably 1,2-hexanediol, excluding the 0, and endpoint;0-95% by weight, preferably 0-50% by weight, more preferably 0-10% by weight, particularly preferably 0-1% by weight of °; 10. Process according to any one of claims 1 to 9, wherein said non-petroleum ethylene glycol comprises, 0-95% by weight, preferably 0.1-50% by weight of 1,2-propanediol; 0-50% by weight, preferably 0.01-10% by weight of 2,3-butanediol; 0-20% by weight, preferably 0.01-10% by weight of glycerol and / or; QFQZnn / įZРZ� / B / YILI 0-20% by weight, preferably 0.01-10% by weight of sorbitol.

11. Process according to any of claims 1 to 10, wherein said non-petroleum-derived ethylene glycol comprises impurities including a trace or even less than the gas chromatography detection limit of acids, ethers, aldehydes, ketones and / or alcohols, etc., affecting the ultraviolet transmittance of the ethylene glycol.

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