Process for separating and recovering epoxy isobutane from industrial by-product waste liquid

Abstract

The present application provides a process for separating and recovering epoxy isobutane from industrial by-product waste liquid. The method obtains high-purity IBO product from a by-product waste liquid of isobutane co-oxidation (PO / TBA) through separation and purification, so as to meet the use of downstream perfume customers. Compared with the prior art, the present application reduces the waste liquid amount of the device, reduces carbon emissions, turns waste into treasure, saves the production cost of IBO, and improves the economic efficiency of the device. On the other hand, compared with the chlorohydrination method and the epoxidation method used in the industry, the method has lower cost, simpler process, and higher market competitiveness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of separation technology, and particularly relates to a process method for separating and recovering industrial by-product waste liquid of epoxy isobutane (IBO). BACKGROUND

[0002] Propylene oxide (PO) is the third largest propylene derivative after polypropylene and acrylonitrile, and is mainly used for producing polyether polyols, propylene glycol, alcohol ether and other products in the downstream, and is extended to the fields of automobiles, furniture, home appliances, high-speed rail, building insulation and daily chemicals. There are four existing production methods, including chlorohydrination method, co-oxidation method, single production method / CHP and direct oxidation method HPPO. The co-oxidation method is mainly divided into isobutane co-oxidation method (PO / TBA) and ethylbenzene co-oxidation method (PO / SM). A large amount of waste liquid is by-produced in the industrial co-oxidation method (PO / TBA) device. The composition of the waste liquid is complex, and in addition to containing a large amount of acetone, the main impurities are epoxy isobutane (IBO), methanol, tertiary butanol and the like. Since the boiling points of the components are small, there are multiple azeotropes such as methanol / acetone, acetone / epoxy isobutane, tertiary butanol / water, and the like, and the conventional separation cannot achieve satisfactory separation effect. Therefore, the utilization of this material is severely limited, and it is generally used as organic waste for incineration to recover part of the heat, and the utilization value is very limited.

[0003] Patents CN201610878107.5 and CN201610875280.X mention the utilization of acetone in the waste liquid by-produced in the co-oxidation method (PO / MTBE) device. In the patents, acetone is converted into methyl isobutyl ketone through condensation dehydration and hydrogenation reaction, so as to realize efficient utilization of the waste liquid, but the epoxy isobutane in the waste liquid is not purified and utilized, and the utilization value of the heat value recovered by incineration is limited.

[0004] Epoxy isobutane (IBO) is an important organic intermediate, which can be used as a raw material to prepare linear musk. Linear musk is a new type of musk that can be degraded by human body, conforms to the trend of green development, and has unique and long-lasting fragrance. At present, it is mainly added to high-end perfumes and is deeply loved by consumers, and the demand is increasing year by year. Epoxy isobutane, as an important raw material for linear musk, has great development potential.

[0005] At present, there are two methods for preparing IBO, namely chlorohydrination method and epoxidation method, and the raw materials for both methods are isobutene. The chlorohydrination method uses isobutene, chlorine and water as raw materials, and goes through three steps of chlorohydrination, saponification and product purification and refining to finally obtain qualified products. A large amount of saponification waste liquid and waste residue are generated in the production process, which pollutes the environment. The epoxidation method uses isobutene and peroxide as raw materials to directly epoxidize isobutene into epoxy isobutane. Although the treatment cost of three wastes is low, the amount of by-products is large, and the profitability of the device is restricted by the market of co-products.

[0006] In summary, the cost of using isobutylene as raw material to prepare IBO is high, and there is no literature report on the purification of IBO from industrial by-product waste liquid, so it is necessary to seek a process method for separating and recovering epoxy isobutane from industrial by-product waste liquid, which can reduce the amount of waste liquid incineration and carbon emission, and can also turn waste into treasure and improve the economic efficiency of the device. SUMMARY

[0007] The purpose of the present application is to provide a process method for separating and recovering epoxy isobutane from industrial by-product waste liquid, in particular, a by-product waste liquid from isobutane co-oxidation method (PO / TBA), which is obtained by separation and purification method to obtain high-purity IBO product with purity ≥97% and water content ≤0.1%, so as to meet the use of downstream perfume customers.

[0008] In order to achieve the above purpose of the application, the technical scheme adopted by the present application is as follows:

[0009] A process method for separating and recovering epoxy isobutane from industrial by-product waste liquid, the method comprises the following steps:

[0010] (S1) extractive distillation: removing all or most of the polar substances from the industrial by-product waste liquid by extractive distillation;

[0011] (S2) distillation: removing components with lower boiling point than IBO first, and then removing components with higher boiling point than IBO; or: removing components with higher boiling point than IBO first, and then removing components with lower boiling point than IBO.

[0012] In the present application, the industrial by-product waste liquid in S1 comes from isobutane co-oxidation device, more specifically from PO / TBA device, and based on the quality of by-product waste liquid, its composition contains 10wt%-90wt% of acetone, 5wt%-70wt% of IBO, 0.5wt%-8wt% of water, 0.01wt%-15wt% of methanol, 0.01wt%-10wt% of MTBE, 0.01wt%-5wt% of tert-butyl alcohol, 0wt%-5wt% of formate, 0.01wt%-5wt% of C3-C5 hydrocarbons, 0.01wt%-10wt% of C6 hydrocarbons, and 0.01wt%-5wt% of C7-C8 hydrocarbons.

[0013] In the present application, extractive distillation is used in S1, and the extractant is selected from one or more mixtures of water, formamide, acetonitrile, monoethanolamine, alcohol and the like, and the alcohol mainly includes methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol and the like. The mass ratio of extractant to raw material is 0.5:1-10:1.

[0014] In the present application, the extractive distillation column used in S1 is operated under the conditions of absolute pressure of 10-500 KPa, preferably 80-300 KPa; the number of theoretical plates is 5-80 plates, preferably 15-50 plates; the feed position is the 3rd-60th plate (from top to bottom, same below), preferably the 10th-35th plate; the reflux ratio is 0.1-10, preferably 2-5; the column top temperature is 20-110 DEG C, and the column bottom temperature is 40-180 DEG C.

[0015] In the preferred embodiment of the present application, the packing of the extractive distillation column in S1 is modified packing, the modified packing is coated with hydroxyethyl cellulose (HEC) on the surface of the metal packing by plasma coating method, the HEC is concentrated on the surface of the packing by using nitrogen as carrier gas in the plasma coating, and the coating thickness is 100-800 nm. The packing can be any one of structured packing and random packing, and the material is selected from 304, 316, 316L, duplex steel and the like.

[0016] In the present application, the molar substitution degree MS of the HEC is 2.4-3, the uniform substitution degree DS is 1.2-1.8, and MS / DS is 1.5-2.

[0017] In the present application, the surface of the packing is coated to increase the content of the polar components on the surface of the metal, and then the wettability of the polar organic matter to the packing is improved, so that the plate height of the extractive column is greatly reduced, and the extraction effect is improved. If the molar substitution degree MS of the coated HEC is lower than 2.4, the viscosity is too low, and the adhesion on the surface of the packing is not firm; if the molar substitution degree MS of the coated HEC is higher than 3, the viscosity is too high, the adhesion on the surface of the packing is not uniform, and the coating thickness is not easy to control between 100-800 nm. If the uniform substitution degree DS of the coated HEC is lower than 1.2, the water solubility of the HEC is poor, the coating on the surface of the packing is not increased greatly in the wettability of the polar organic matter; if the uniform substitution degree DS of the coated HEC is higher than 1.8, the water solubility of the HEC is strong, and the coating is seriously lost in the extraction process. In addition, MS / DS is preferably controlled between 1.5-2, if MS / DS is lower than 1.5, it means that the hydroxyl on the sugar ring of the cellulose is substituted by more hydroxymethyl, but the generated substituted ether group is not much, so that the wettability of the coated HEC to the organic matter is poor; if MS / DS is higher than 2, it means that the hydroxyl on the sugar ring of the cellulose is substituted by less hydroxymethyl, but the generated substituted ether group is more, so that the coated HEC is unstable, easy to be enzymatically hydrolyzed, and poor in transparency.

[0018] In the present application, if water is used as the extractant, the adsorption dehydration process is preferably added in S2. The adsorption dehydration process can be added at any stage after the extractive rectification tower. Specifically, the adsorption dehydration process can be before the light component removal tower, after the light component removal tower, before the heavy component removal tower, or after the heavy component removal tower. The adsorbent used is one or more of alumina, molecular sieve, and diatomite, preferably molecular sieve. The adsorption pressure is 100-1000 KPa, and the temperature is 10-60℃.

[0019] In the present application, the IBO light component removal tower is used to remove components with a boiling point lower than that of IBO in S2. The tower is operated at an absolute pressure of 10-1000 KPa, preferably 50-500 KPa; the theoretical plate number is 20-100 plates, preferably 40-80 plates; the feed position is the 5th-80th plate, preferably the 20th-50th plate; the reflux ratio is 1-100, preferably 10-50; the tower top temperature is 10℃-100℃, and the tower bottom temperature is 30℃-150℃.

[0020] The IBO heavy component removal tower is used to remove components with a boiling point higher than that of IBO. The tower is operated at an absolute pressure of 10-500 KPa, preferably 50-200 KPa; the theoretical plate number is 20-100 plates, preferably 40-80 plates; the feed position is the 5th-80th plate, preferably the 20th-50th plate; the reflux ratio is 0.1-20, preferably 1-5; the tower top temperature is 10℃-120℃, and the tower bottom temperature is 30℃-130℃.

[0021] The IBO product with a purity of ≥97% and a water content of ≤0.1% can be prepared by using the above-mentioned preferred separation method.

[0022] Compared with the prior art, the present application has the following positive effects:

[0023] (1) The IBO is extracted from the waste liquid of the isobutane co-oxidation device by using the above-mentioned method, which reduces the waste liquid discharge and the carbon emission of the device, and reduces the treatment cost of the three wastes of the device.

[0024] (2) The present application turns waste into treasure, saves the production cost of IBO, and improves the comprehensive economic benefit of the device.

[0025] (3) The present application has lower raw material cost and simpler process than the chlorohydrination method and the epoxidation method used in industry, and is more competitive in the market. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with examples. These examples are only used to illustrate the present application, and do not limit the scope of the present application.

[0027] The main raw material information is as follows:

[0028] Raw material name Specification Factory Raw material PO / TBA device by-product Molecular sieve 4A Union carbide company Molecular sieve 3A Union carbide company Alumina 2-4mm Zhengzhou Jinbang environmental protection technology Co., Ltd. Diatomaceous earth 325-500 mesh Lingshou Shengya mineral Co., Ltd. Hydroxyethyl cellulose ether Asia Lan Chemical Co., Ltd.

[0029] The device information is as follows:

[0030] Equipment name Equipment specification Equipment factory Heat collecting constant temperature magnetic stirring bath HWCL-3 Zhengzhou Great Wall Science and Technology Co., Ltd. Rectifying column Changshun Fine Chemicals Co., Ltd. Science and Technology Institute Diaphragm vacuum pump SC920 Germany KNF

[0031] The gas chromatography analysis conditions are as follows:

[0032] Analysis instrument: Shimadzu HP-PONA (specification: 50 m x 0.2 mm x 0.5 μm);

[0033] Gas analysis method: correction normalization method;

[0034] Gas analysis conditions: vaporization chamber temperature: 230°C, detector temperature: 300°C, column temperature: programmed temperature rise: 40°C, 8 min; 10°C / min to 240°C.

[0035] The compositions of the raw materials used in each of the comparative examples and the examples are shown in Table 1:

[0036] Table 1 Composition of raw materials (wt%)

[0037] Raw material 1 Raw material 2 Raw material 3 Raw material 4 Acetone 50 10 90 20 IBO 10 70 5 27 Water 3 0.5 4.94 8 Methanol 2.5 11.5 0.01 15 MTBE 8 2 0.01 10 Tert-butyl alcohol 5 1 0.01 3 Formate 5 1 0 2 C3-C5 hydrocarbon 3 1 0.01 5 C6 hydrocarbon 10 2 0.01 5 C7-C8 hydrocarbon 3.5 1 0.01 5

[0038] Comparative Example 1

[0039] Comparative Example 1 only uses rectification to separate the byproduct waste liquid, and the composition of the raw material is shown in Table 1 as raw material 1. The material in raw material 1 is subjected to light removal and heavy removal through two rectification towers, and the operating conditions of the light removal tower and the heavy removal tower are consistent with those in Example 1. After rectification through the two towers, the purity of the IBO product is 55.8%, and the water content is 0.05%.

[0040] Example 1

[0041] The 252Y structured packing of 304 material is soaked in ethanol at room temperature for 2 h, and then dried in an explosion-proof oven at 50-80°C for 6 h. The HEC with a molar substitution degree MS of 2.4, a uniform substitution degree DS of 1.2, and an MS / DS of 2 is placed in a plasma spraying machine, and nitrogen is used as the carrier gas to uniformly spray it onto the surface of the packing. The spraying thickness is controlled to be 100 nm, and the modified packing 1 is obtained.

[0042] Raw material 1 is subjected to extraction rectification tower to remove most of the acetone, water, methanol and tert-butyl alcohol, and the extraction rectification tower is filled with modified packing 1. The extractant is hexanediol, and the mass ratio of hexanediol to raw material 1 is 2.5:1.

[0043] The overhead material of the extraction rectification tower is subjected to a light removal tower, and formate esters and C3-C5 hydrocarbons are removed at the top. The column bottom liquid enters a heavy removal tower, and IBO product is obtained at the top, and the column bottom is mainly heavy components. The operating conditions of the extraction tower, the light removal tower and the heavy removal tower are shown in Table 2. Finally, the product purity is 97.5%, and the water content is 0.002%.

[0044] Table 2 Operating conditions

[0045] Extractive distillation column Light removal column Heavy removal column Pressure, KPa 100 500 50 Theoretical plate number 40 80 70 Feeding position 20 40 40 Reflux ratio 5 50 5 Overhead temperature, ℃ 49.0 74.9 31.5 Bottom temperature, ℃ 75.1 111.8 34.6

[0046] Example 2

[0047] The BX structured packing of 316L material was soaked in ethanol at room temperature for 2 h, and then dried in an explosion-proof oven at 50-80°C for 6 h. The HEC with a molar substitution degree MS of 2.8, a uniform substitution degree DS of 1.6, and MS / DS of 1.75 was placed in a plasma spraying machine, and uniformly sprayed onto the surface of the packing by using nitrogen as the carrier gas. The spraying thickness was controlled to be 400 nm, and modified packing 2 was obtained.

[0048] The raw material 2 was subjected to extraction rectification tower to remove most of the acetone, water, methanol and tert-butyl alcohol, and the extraction rectification tower was filled with modified packing 2. The extractant was ethylene glycol, and the mass ratio of ethylene glycol to raw material 2 was 2:1.

[0049] The overhead material was subjected to a light-removing tower, and the overhead was removed from the formate and C3-C5 hydrocarbons. The tower bottom liquid was subjected to a heavy-removing tower, and the tower bottom was removed from the components heavier than IBO. The operating conditions of the extraction rectification tower, the light-removing tower and the heavy-removing tower are shown in Table 3. Finally, the product purity was 98.2%, and the water content was 0.03%.

[0050] Table 3 Operating conditions

[0051] Extractive distillation column Light removal column Heavy removal column Pressure, KPa 500 100 100 Theoretical plate number 5 50 100 Feeding position 3 20 80 Reflux ratio 10 30 0.1 Overhead temperature, ℃ 100.3 51.2 52.8 Bottom temperature, ℃ 162.7 53.7 58.5

[0052] Example 3

[0053] The Pall ring bulk modified packing of 2205 material was soaked in ethanol at room temperature for 2 h, and then dried in an explosion-proof oven at 50-80°C for 6 h. The HEC with a molar substitution degree MS of 2.6, a uniform substitution degree DS of 1.73, and MS / DS of 1.5 was placed in a plasma spraying machine, and uniformly sprayed onto the surface of the packing by using nitrogen as the carrier gas. The spraying thickness was controlled to be 500 nm, and modified packing 3 was obtained.

[0054] The raw material 3 was subjected to extraction rectification tower to remove most of the acetone, water, and the extraction rectification tower was filled with modified packing 3. The extractant was water, and the mass ratio of water to raw material 3 was 0.5:1.

[0055] The overhead material was subjected to a light-removing tower, and the overhead was removed from the formate and C3-C5 hydrocarbons. The tower bottom liquid was subjected to 3A molecular sieve adsorption dehydration at an adsorption temperature of 10°C and an adsorption pressure of 100 KPa. The material after adsorption dehydration was subjected to a heavy-removing tower, and the tower bottom was removed from the components heavier than IBO. The overhead obtained IBO product. The operating conditions of the extraction tower, the light-removing tower and the heavy-removing tower are shown in Table 4. Finally, the product purity was 97.8%, and the water content was 0.04%.

[0056] Table 4 Operating conditions

[0057] Extractive distillation column Light removal column Heavy removal column Pressure, KPa 50 50 200 Theoretical plate number 50 20 50 Feeding position 30 5 20 Reflux ratio 3 100 10 Overhead temperature, ℃ 34.9 33.6 74.3 Bottom temperature, ℃ 42.8 39.7 77.7

[0058] Example 4

[0059] The raw material 4 is removed from most of the acetone, water, methanol and tert-butyl alcohol by an extractive rectification column, the extractive rectification column uses 304 material saddle ring modified packing, the packing surface is sprayed with HEC with a thickness of 800 nm, and the molar substitution degree MS of HEC is 3, the uniform substitution degree DS is 1.8, and MS / DS is 1.67. The extractant is water, and the mass ratio of water to raw material 4 is 10:1.

[0060] The overhead material is removed from formate and C3-C5 hydrocarbons by a light removal column, and the column liquid is removed from components heavier than IBO by a heavy removal column, and the overhead crude IBO is removed by 4A molecular sieve adsorption dehydration, the adsorption temperature is 60°C, the adsorption pressure is 1000KPa, and the material after adsorption dehydration. The operating conditions of the extractive column, the light removal column and the heavy removal column are shown in Table 5. Finally, the product purity is 98.6%, and the water content is 0.04%.

[0061] Table 5 Operating conditions

[0062] Extractive distillation column Light removal column Heavy removal column Pressure, KPa 150 1000 500 Theoretical plate number 80 100 20 Feeding position 60 80 5 Reflux ratio 1 1 20 Overhead temperature, ℃ 43.0 94.1 110.2 Bottom temperature, ℃ Extractive distillation column Light removal column Heavy removal column Pressure, KPa Theoretical plate number Feeding position Reflux ratio Overhead temperature, ℃ Bottom temperature, ℃ 81.3 140.6 111.8

[0063] Example 5

[0064] Compared with Example 2, the extractive rectification column uses uncoated modified packing, and the rest of the conditions are consistent with Example 2, the raw material uses raw material 2, and the material in raw material 2 is removed by an extractive rectification column, the overhead material is removed by a light removal column and a heavy removal column, and the final IBO product purity is 94.5%, of which the acetone content is 4.3%, and the water content is 0.21%.

[0065] Example 6

[0066] Compared with Example 3, there is no adsorption dehydration process, and the rest of the conditions are consistent with Example 3, the raw material liquid uses raw material 3, and part of the components in the raw material are removed by an extractive rectification column, and then the overhead components are removed by a light removal column and a heavy removal column to obtain an IBO product, and the product purity is 95.4%, and the water content is 1.3%.

Claims

1. A method for separating and recovering an industrial by-product waste liquid of isobutylene oxide, characterized by, The method comprises the following steps: (S1) extractive distillation: removing all or most of the polar substances in the industrial by-product waste liquid by extractive distillation; The industrial by-product waste liquid is from an isobutane co-oxidation device, and its composition comprises 10wt%-90wt% of acetone, 5wt%-70wt% of IBO, 0.5wt%-8wt% of water, 0.01wt%-15wt% of methanol, 0.01wt%-10wt% of MTBE, 0.01wt%-5wt% of tert-butyl alcohol, 0wt%-5wt% of formate, 0.01wt%-5wt% of C3-C5 hydrocarbons, 0.01wt%-10wt% of C6 hydrocarbons, and 0.01wt%-5wt% of C7-C8 hydrocarbons, based on the mass of the by-product waste liquid. The packing of the extractive distillation column is modified packing, the modified packing is coated with hydroxyethyl cellulose (HEC) on the surface of the metal packing by a plasma coating method, the coating thickness is 100-800nm, the molar substitution degree (MS) of the HEC is 2.4-3, the uniform substitution degree (DS) is 1.2-1.8, and the MS / DS is 1.5-2. The extractive agent for extractive distillation is selected from water and alcohol, and the alcohol is at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, propylene glycol, butanediol, pentanediol and hexanediol. (S2) distillation: removing components with lower boiling points than IBO first, and then removing components with higher boiling points than IBO.

2. The method of claim 1, wherein, The extractive distillation column is operated at an absolute pressure of 10-500KPa, the theoretical plate number is 5-80 plates, the feed position is the 3rd-60th plate, the reflux ratio is 0.1-10, the column top temperature is 20-110℃, and the column bottom temperature is 40-180℃.

3. The method of claim 2, wherein, The extractive distillation column is operated at an absolute pressure of 80-300KPa, the theoretical plate number is 15-50 plates, the feed position is the 10th-35th plate, and the reflux ratio is 2-5.

4. The method of claim 1, wherein, The IBO light-removing column is used to remove the components with lower boiling points than IBO, the column is operated at an absolute pressure of 10-1000KPa, the theoretical plate number is 20-100 plates, the feed position is the 5th-80th plate, the reflux ratio is 1-100, the column top temperature is 10-100℃, and the column bottom temperature is 30-150℃.

5. The method of claim 4, wherein, The IBO light-removing column is used to remove the components with lower boiling points than IBO, the column is operated at an absolute pressure of 50-500KPa, the theoretical plate number is 40-80 plates, the feed position is the 20th-50th plate, and the reflux ratio is 10-50.

6. The method of claim 1, wherein, The IBO heavy-removing column is used to remove the components with higher boiling points than IBO, the column is operated at an absolute pressure of 10-500KPa, the theoretical plate number is 20-100 plates, the feed position is the 5th-80th plate, the reflux ratio is 0.1-20, the column top temperature is 10-120℃, and the column bottom temperature is 30-130℃.

7. The method of claim 6, wherein, S2 said removal of components with higher boiling point than IBO using IBO heavy tower, which is operated at 50-200 KPa absolute; the number of theoretical plates is 40-80 plates; the feed position is the 20-50 plates; the reflux ratio is 1-5.

8. The method according to any one of claims 1-7, characterized in that, If water is used as the extractant, an adsorption dehydration process is added in S2, using one or more of alumina, molecular sieve, diatomite as the adsorbent, the adsorption pressure is 100-1000 KPa, and the temperature is 10-60℃.