Method for purifying ethanol from crude ethanol prepared from coal gasification methanol

Abstract

The invention discloses a method for purifying ethanol from a crude ethanol product prepared from coal gasification methanol, and is used to solve the technical problem that the purity and purification conversion rate of ethanol purified from the crude ethanol product prepared from coal gasification methanol in the prior art need to be further improved. The invention comprises the following steps: a separation aid liquid with a temperature of 90-95 DEG C is input into the middle and upper part of an ethanol distillation tower filled with aminated porous fillers, and flows from top to bottom in the ethanol distillation tower, and the crude ethanol product enters the interior of the ethanol distillation tower from a feed pipe, and the crude ethanol product contacts and mixes with the separation aid liquid; the invention adopts the aminated porous filler as the filler of the ethanol distillation tower, and cooperates with the separation aid liquid, and optimizes the distillation conditions, so as to effectively improve the purity of an ethanol product obtained by distilling and purifying the crude ethanol product, and also improve the purification yield of ethanol.

Description

Technical Field

[0001] The invention relates to the technical field of ethanol purification, and in particular to a method for purifying ethanol from crude ethanol prepared from coal gasification methanol. Background Art

[0002] Gasification methanol is a kind of methanol produced by comprehensive utilization of coke oven gas and regeneration and conversion of coke oven gas. In actual production tests, methanol exhaust gas is used as raw material, and after carbon supplementation through gasification, the methanol output can be further increased. However, the preparation of ethanol from methanol as raw material requires a series of chemical reactions such as dimethyl ether, carbonylation, and hydrogenation separation, and then the prepared crude ethanol is purified to obtain finished ethanol.

[0003] In the prior art, impurities in crude ethanol prepared from coal gasification methanol mainly include impurities in the raw materials, such as water, and also include incompletely converted methanol, aldehydes, ketones, esters, and other alcohol impurities such as propanol and butanol. The crude ethanol is often purified by distillation. However, water, acidic impurities or other impurities that can azeotropy with ethanol contained in the crude ethanol are difficult to separate from ethanol during the distillation process, resulting in the purity of ethanol to be further improved. The traditional method of using high towers or multi-stage distillation will increase the purification cost of ethanol, increase the loss of ethanol, and result in a decrease in the purification conversion rate of ethanol.

[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0005] The object of the present invention is to provide a method for purifying ethanol from crude ethanol prepared from coal gasification methanol, so as to solve the technical problem in the prior art that the purity and purification conversion rate of ethanol purified from crude ethanol prepared from coal gasification methanol need to be further improved.

[0006] The object of the present invention can be achieved by the following technical scheme: A method for purifying ethanol from crude ethanol prepared from coal gasification methanol comprises the following steps:

[0007] S1, inputting the separation aid liquid at a temperature of 90-95°C into the middle and upper part of the ethanol distillation tower filled with aminated porous filler, and flowing from top to bottom in the ethanol distillation tower;

[0008] S2, crude ethanol enters the interior of the ethanol distillation tower from the feed pipe, the crude ethanol is contacted and mixed with the separation aid liquid, the low boiling point molecules in the mixture are vaporized, and then continue to flow upward, the ethanol molecules are sampled from the ethanol side sampling pipe, and the remaining gas molecules are discharged from the tower top discharge pipe, and the high boiling point molecules are mixed with the separation aid liquid and collected at the bottom of the ethanol distillation tower;

[0009] S3. The separation aid liquid collected at the bottom of the ethanol distillation tower is regenerated by a regeneration system coordinated with the ethanol distillation tower and then enters the ethanol distillation tower for recycling.

[0010] Furthermore, the number of plates of the ethanol distillation tower is 100, and from bottom to top, the temperature of the first plate to the thirty-fifth plate layer is 110-120°C, the temperature of the thirty-fifth plate to the sixty-fifth plate layer decreases layer by layer to 90-95°C, the temperature of the sixty-fifth plate to the eightieth plate layer decreases layer by layer to 80-83°C, the temperature of the eightieth plate to the hundredth plate layer is kept at 80-83°C, and the operating pressure of the ethanol distillation tower is 0.02-0.03MPa.

[0011] Furthermore, one end of the feed pipe extending into the interior of the ethanol distillation tower is located at the top of the 35th tower plate layer, and one end of the ethanol side sampling pipe extending into the interior of the ethanol distillation tower is located at the top of the 80th tower plate layer.

[0012] Furthermore, the auxiliary separation liquid is composed of ethylene glycol, dimethyl sulfoxide, and 3-amino-1,2-propylene glycol in a volume ratio of 3:10:2, and the volume ratio of the auxiliary separation liquid and the crude ethanol product input into the ethanol distillation tower is 3-5:9.

[0013] Furthermore, the regeneration system includes a shell-and-tube thin film evaporator, a connecting pipe 1 installed at the input end of the shell-and-tube thin film evaporator, and a connecting pipe 2 installed at the output end of the shell-and-tube thin film evaporator, the other end of the connecting pipe 1 is connected to the inner bottom of the ethanol distillation tower, a heat exchanger is installed on the connecting pipe 2, one end of the connecting pipe 2 away from the shell-and-tube thin film evaporator is connected to the interior of the ethanol distillation tower, and the connecting pipe 2 is located at the top of the sixty-fifth tower plate layer inside the ethanol distillation tower.

[0014] Furthermore, the operating temperature of the shell-and-tube thin film evaporator is 145-150° C., the pressure is normal pressure, and an air guide pipe connected to the condenser is provided on the top of the shell-and-tube thin film evaporator.

[0015] Furthermore, the preparation method of the aminated porous filler is: mix the porous filler, anhydrous ethanol and 3-aminopropyltriethoxysilane, ultrasonically disperse for 30-50 minutes, stir, increase the temperature of the reaction system to 50-60°C, add ammonia water to the reaction system, keep the reaction warm for 60-90 minutes, and post-treat to obtain the aminated porous filler.

[0016] The synthetic reaction mechanism of aminated porous filler is:

[0017] During the preparation process, ultrasonic dispersion is used to promote the uniform dispersion of 3-aminopropyltriethoxysilane molecules and porous fillers. In an alkaline environment, the siloxane bonds on the 3-aminopropyltriethoxysilane molecules are hydrolyzed to form silanol groups that chemically bond with active sites on the surface of the porous filler particles, thereby preparing an amino-modified aminated porous filler.

[0018] Furthermore, the amount ratio of the porous filler, anhydrous ethanol, 3-aminopropyltriethoxysilane and ammonia water is 5g:50mL:2g:10mL, the mass fraction of the ammonia water is 5-8%, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80°C, and vacuum dried to constant weight to obtain an aminated porous filler.

[0019] Furthermore, the porous filler is obtained by processing the following steps:

[0020] A1. Mix fly ash, cement, calcium hydroxide and cellulose to obtain a mixture;

[0021] A2. Add deionized water to the mixture, stir evenly, and transfer it to a disc granulator for granulation to obtain a filler blank with a particle size of 5-8 mm;

[0022] A3. Place the filler blank in an environment with a temperature of 45-55°C, cure for 5 days, and then calcine to obtain a porous filler.

[0023] The synthetic reaction mechanism of porous fillers is:

[0024] During the preparation process, the mixture goes through the granulation and wet curing stages. The active ingredients in the fly ash dissolve and react with cement to form a hydration reaction. Calcium hydroxide acts as an alkaline activator to promote the reaction of aluminosilicates in the fly ash to form a preliminary particle structure. During the high-temperature roasting stage, the cement hydration products, aluminosilicates in the fly ash and calcium hydroxide react chemically to form a stable mineral phase. At the same time, cellulose decomposes to produce pores, eventually forming a porous filler.

[0025] Furthermore, in step A1, the weight ratio of fly ash, cement, calcium hydroxide and cellulose is 7-8:0.9-1.3:2.1-2.5:1.2-1.5; in step A2, the dosage ratio of the mixture and deionized water is 10g:2-3mL; in step A3, the roasting temperature is 380-400°C and the roasting time is 3-5h.

[0026] The present invention has the following beneficial effects:

[0027] 1. The present invention uses aminated porous fillers as fillers for an ethanol distillation tower, optimizes distillation conditions, and uses a separation aid composed of ethylene glycol, dimethyl sulfoxide, and 3-amino-1,2-propylene glycol to promote the separation of impurity molecules with high boiling points, acidity, and other properties from ethanol during the distillation process of crude ethanol, thereby improving the purity of the ethanol product and the purification yield of ethanol.

[0028] 2. The present invention is a mixture composed of fly ash, cement, calcium hydroxide and cellulose, which is then hydrated, granulated and cured to promote the cement hydration product in the filler blank to form a stable mineral phase with materials such as silicate. At the same time, cellulose is used as a porogen to decompose at high temperature to form porous filler balls. The porous structure of the filler provides a large number of adsorption sites for impurities. The active ingredients therein, such as calcium hydroxide, have strong alkalinity to form ionic bonds with acidic impurities in crude ethanol, thereby promoting the separation of acidic impurities from ethanol in the crude ethanol. At the same time, the nitrogen atoms on the amino functional groups modified on the porous filler particles have lone pairs of electrons, which can form chemical adsorption with impurities containing carboxyl groups, aldehyde groups, etc. in the crude ethanol, thereby enhancing the interaction between the porous filler and the impurities in the crude ethanol, promoting the separation effect of impurities and ethanol in the filler layer, and improving the separation effect of impurities.

[0029] 3. The present invention optimizes the distillation conditions and regulates the temperature of the distillation sections of different tower plates to promote the mixing of the crude ethanol product with the separation aid liquid in the distillation tower. After the impurities in the crude ethanol product are adsorbed and separated, the ethylene glycol, dimethyl sulfoxide and 3-amino-1,2-propylene glycol in the separation aid liquid have good permeability and hydrophilicity, and can form a mixed system with the water in the crude ethanol product, thereby increasing the azeotropic point of water in the crude ethanol product, thereby effectively promoting the separation of water in the crude ethanol product from the crude ethanol product. At the same time, dimethyl sulfoxide and 3-amino-1,2-propylene glycol can promote the separation of impurities in the crude ethanol product by chemical adsorption. In addition, each component of the separation aid liquid has a high boiling point, and the impurities in the separation aid liquid can be removed by high-temperature treatment, thereby realizing the recycling of the separation aid liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a process flow chart of the present invention.

[0032] In the figure: 100, ethanol distillation tower; 101, feed pipe; 102, ethanol side sampling pipe; 103, tower top discharge pipe; 104, connecting pipe 1; 200, shell and tube thin film evaporator; 201, connecting pipe 2; 202, heat exchanger. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The fly ash in the present invention is Class F fly ash and the cement is Portland cement.

[0035] Example 1

[0036] This embodiment provides a method for preparing an aminated porous filler for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0037] A1. Mix fly ash, cement, calcium hydroxide and cellulose in a weight ratio of 7:0.9:2.1:1.2 to obtain a mixture.

[0038] A2. Weigh: add 2L of deionized water to 10kg of the mixed material, stir evenly, transfer it to a disc granulator, granulate, and obtain a filler blank with a particle size of 5-8mm.

[0039] A3. Place the filler blank in an environment with a temperature of 45°C and a humidity of 50%. After curing for 5 days, transfer it to a tubular furnace with a temperature of 380°C, keep it warm and bake it for 3 hours, cool it naturally to room temperature, and discharge it to obtain a porous filler.

[0040] A4. Weigh: 1 kg of porous filler, 10 L of anhydrous ethanol and 400 g of 3-aminopropyltriethoxysilane, add them into a plastic barrel, and perform ultrasonic dispersion for 30 min. Transfer the mixed system to a stirring tank and stir. The temperature of the stirring tank is raised to 50° C., 2 L of 5 wt % ammonia water is added to the stirring tank, and the mixture is kept warm for 60 min. The temperature of the stirring tank is lowered to room temperature, and the mixture is filtered. The filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 70° C. and vacuum dried to constant weight to obtain an aminated porous filler.

[0041] Example 2

[0042] This embodiment provides a method for preparing an aminated porous filler for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0043] A1. Evenly mix fly ash, cement, calcium hydroxide and cellulose in a weight ratio of 7.5:1.1:2.3:1.4 to obtain a mixture.

[0044] A2. Weigh: add 2.5L of deionized water to 10kg of the mixed material, stir evenly, transfer it to a disc granulator, granulate, and obtain a filler blank with a particle size of 5-8mm.

[0045] A3. Place the filler blank in an environment with a temperature of 50°C and a humidity of 50%. After curing for 5 days, transfer it to a tubular furnace with a temperature of 390°C, keep it warm and bake it for 4 hours, cool it naturally to room temperature, and discharge it to obtain a porous filler.

[0046] A4. Weigh: 1 kg of porous filler, 10 L of anhydrous ethanol and 400 g of 3-aminopropyltriethoxysilane, add them into a plastic barrel, and perform ultrasonic dispersion for 40 min. Transfer the mixed system to a stirring tank and stir. The temperature of the stirring tank is raised to 55° C., 2 L of 7 wt % ammonia water is added to the stirring tank, and the reaction is kept warm for 75 min. The temperature of the stirring tank is lowered to room temperature, and the filter cake is filtered. The filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 75° C. and vacuum dried to constant weight to obtain an aminated porous filler.

[0047] Example 3

[0048] This embodiment provides a method for preparing an aminated porous filler for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0049] A1. Evenly mix fly ash, cement, calcium hydroxide and cellulose in a weight ratio of 8:1.3:2.5:1.5 to obtain a mixture.

[0050] A2. Weigh: add 3L of deionized water to 10kg of the mixed material, stir evenly, transfer it to a disc granulator, granulate, and obtain a filler blank with a particle size of 5-8mm.

[0051] A3. Place the filler blank in an environment with a temperature of 55°C and a humidity of 50%. After curing for 5 days, transfer it to a tubular furnace with a temperature of 400°C, keep it warm and bake it for 5 hours, cool it naturally to room temperature, and discharge it to obtain a porous filler.

[0052] A4. Weigh: 1 kg of porous filler, 10 L of anhydrous ethanol and 400 g of 3-aminopropyltriethoxysilane, add them into a plastic barrel, and perform ultrasonic dispersion for 50 min. Transfer the mixed system to a stirring tank and stir. The temperature of the stirring tank is raised to 60° C., 2 L of 8 wt % ammonia water is added to the stirring tank, and the reaction is kept warm for 90 min. The temperature of the stirring tank is lowered to room temperature, and the filter cake is filtered. The filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 80° C. and vacuum dried to constant weight to obtain an aminated porous filler.

[0053] Example 4

[0054] See also Figure 1 This embodiment provides a method for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0055] S1. The aminated porous filler prepared in Example 1 is placed on the top of each plate layer of an ethanol distillation tower 100 having 100 plates. The operating pressure of the ethanol distillation tower 100 is set to 0.02 MPa. From bottom to top, the temperature of the first plate to the thirty-fifth plate layer is increased to 110° C., the temperature of the thirty-fifth plate to the sixty-fifth plate layer is gradually reduced to 90° C., the temperature of the sixty-fifth plate to the eightieth plate layer is gradually reduced to 80° C., and the temperature of the eightieth plate to the hundredth plate layer is kept at 80° C.

[0056] S2. The separation liquid with a temperature of 90° C. is transported to the top of the sixty-fifth plate layer of the ethanol distillation tower 100, and the crude ethanol product enters the top of the thirty-fifth plate layer of the ethanol distillation tower 100 from the feed pipe 101. The crude ethanol product contacts and mixes with the separation liquid, and the low-boiling point molecules in the mixture are vaporized and then continue to flow upward. The ethanol molecules are sampled from the ethanol side sampling pipe 102 located at the top of the eightieth plate layer, and the remaining gas molecules are discharged from the tower top discharge pipe 103. The high-boiling point molecules are mixed with the separation liquid and collected at the bottom of the ethanol distillation tower 100, wherein the separation liquid is composed of ethylene glycol, dimethyl sulfoxide, and 3-amino-1,2-propylene glycol in a volume ratio of 3:10:2, and the volume ratio of the separation liquid and the crude ethanol product input to the ethanol distillation tower is 3:9.

[0057] S3. The liquid collected at the bottom of the ethanol distillation tower 100 enters the interior of the shell-and-tube thin film evaporator 200 with a temperature of 145°C through the connecting pipe 104. After heat exchange and evaporation, the low-boiling substances in the liquid are vaporized and evaporated, and are discharged through the top air guide pipe and condensed. The regenerated liquid collected at the bottom of the shell-and-tube thin film evaporator 200 is maintained at 68°C after heat exchange in the heat exchanger 202 with the help of an external liquid delivery pump, and then re-enters the ethanol distillation tower 100 to realize the regeneration cycle of the separation aid liquid.

[0058] Example 5

[0059] See also Figure 1 This embodiment provides a method for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0060] S1. The aminated porous filler prepared in Example 2 is placed on the top of each plate layer of an ethanol distillation tower 100 having 100 plates. The operating pressure of the ethanol distillation tower 100 is set to 0.025 MPa. From bottom to top, the temperature of the first plate to the thirty-fifth plate layer is increased to 115° C., the temperature of the thirty-fifth plate to the sixty-fifth plate layer is gradually reduced to 93° C., the temperature of the sixty-fifth plate to the eightieth plate layer is gradually reduced to 82° C., and the temperature of the eightieth plate to the hundredth plate layer is kept at 82° C.

[0061] S2. The separation liquid with a temperature of 93° C. is transported to the top of the sixty-fifth plate layer of the ethanol distillation tower 100, and the crude ethanol product enters the top of the thirty-fifth plate layer of the ethanol distillation tower 100 from the feed pipe 101. The crude ethanol product contacts and mixes with the separation liquid, and the low-boiling point molecules in the mixture are vaporized and then continue to flow upward. The ethanol molecules are sampled from the ethanol side sampling pipe 102 located at the top of the eightieth plate layer, and the remaining gas molecules are discharged from the tower top discharge pipe 103. The high-boiling point molecules are mixed with the separation liquid and collected at the bottom of the ethanol distillation tower 100, wherein the separation liquid is composed of ethylene glycol, dimethyl sulfoxide, and 3-amino-1,2-propylene glycol in a volume ratio of 3:10:2, and the volume ratio of the separation liquid and the crude ethanol product input to the ethanol distillation tower is 4:9.

[0062] S3. The liquid collected at the bottom of the ethanol distillation tower 100 enters the interior of the shell-and-tube thin film evaporator 200 with a temperature of 147°C through the connecting pipe 104. After heat exchange and evaporation, the low-boiling substances in the liquid are vaporized and evaporated, and are discharged through the top air guide pipe and condensed. The regenerated liquid collected at the bottom of the shell-and-tube thin film evaporator 200 is maintained at 71°C after heat exchange in the heat exchanger 202 with the help of an external liquid delivery pump, and then re-enters the ethanol distillation tower 100 to realize the regeneration cycle of the separation aid liquid.

[0063] Example 6

[0064] See also Figure 1 This embodiment provides a method for purifying ethanol from crude ethanol prepared from coal gasification methanol, comprising the following steps:

[0065] S1. The aminated porous filler prepared in Example 3 is placed on the top of each plate layer of an ethanol distillation tower 100 having 100 plates. The operating pressure of the ethanol distillation tower 100 is set to 0.03 MPa. From bottom to top, the temperature of the first plate to the thirty-fifth plate layer is increased to 120° C., the temperature of the thirty-fifth plate to the sixty-fifth plate layer is gradually reduced to 95° C., the temperature of the sixty-fifth plate to the eightieth plate layer is gradually reduced to 83° C., and the temperature of the eightieth plate to the hundredth plate layer is kept at 83° C.

[0066] S2. The separation liquid with a temperature of 95° C. is transported to the top of the sixty-fifth plate layer of the ethanol distillation tower 100, and the crude ethanol product enters the top of the thirty-fifth plate layer of the ethanol distillation tower 100 from the feed pipe 101. The crude ethanol product contacts and mixes with the separation liquid, and the low-boiling point molecules in the mixture are vaporized and then continue to flow upward. The ethanol molecules are sampled from the ethanol side sampling pipe 102 located at the top of the eightieth plate layer, and the remaining gas molecules are discharged from the tower top discharge pipe 103. The high-boiling point molecules are mixed with the separation liquid and collected at the bottom of the ethanol distillation tower 100, wherein the separation liquid is composed of ethylene glycol, dimethyl sulfoxide, and 3-amino-1,2-propylene glycol in a volume ratio of 3:10:2, and the volume ratio of the separation liquid and the crude ethanol product input to the ethanol distillation tower is 5:9.

[0067] S3. The liquid collected at the bottom of the ethanol distillation tower 100 enters the interior of the shell-and-tube thin film evaporator 200 with a temperature of 150°C through the connecting pipe 104. After heat exchange and evaporation, the low-boiling substances in the liquid are vaporized and evaporated, and are discharged through the top air duct and condensed. The regenerated liquid collected at the bottom of the shell-and-tube thin film evaporator 200 is maintained at 74°C after heat exchange in the heat exchanger 202 with the help of an external liquid delivery pump, and then re-enters the ethanol distillation tower 100 to realize the regeneration cycle of the separation aid liquid.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 6 is that the aminated porous filler used in step S1 is replaced by the porous filler in Example 1.

[0070] Comparative Example 2

[0071] The difference between this comparative example and Example 6 is that, in the preparation process, step A1, no calcium hydroxide is added to the aminated porous filler used in step S1.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 6 is that in step S2, no 3-amino-1,2-propanediol is added to the separation aid liquid.

[0074] Comparative Example 4

[0075] The difference between this comparative example and Example 6 is that in step S1, the operating pressure is normal pressure.

[0076] Performance Testing:

[0077] The ethanol content, moisture content, acid content, aldehyde content and methanol concentration of the ethanol samples prepared in Examples 4-6 and Comparative Examples 1-4 were measured with reference to the standard GB / T 6820-2016 "Industrial Ethanol";

[0078] Reference formula , the purification yield of ethanol prepared by purifying crude ethanol in Examples 4-6 and Comparative Examples 1-4 is determined, wherein, is the ethanol production, is the mass fraction of ethanol product, is the amount of crude ethanol added, is the mass fraction of ethanol in crude ethanol. The specific test results are shown in Table 1 below.

[0079] Table 1-Performance test data of the sample

[0080]

[0081] Data Analysis:

[0082] A comparative analysis of the data in Table 1 above shows that the content of the finished ethanol prepared by the present invention reaches 99.95%, the moisture content is reduced to 0.06%, the acid content is reduced to 7.51 mg / L, the aldehyde content is reduced to 8.84 mg / L, the methanol concentration is reduced to 23.3 mg / L, the content of C4+C5 alcohol is reduced to 11.8 mg / L, the purification yield reaches 92.3%, and all performance test data are better than those of the comparative example. The present invention uses aminated porous filler as the filler of the ethanol distillation tower and cooperates with the separation aid liquid to distill and purify the crude ethanol prepared from coal gasification methanol under optimized distillation conditions, which not only effectively improves the purity of the ethanol product obtained by the distillation and purification of the crude ethanol product, but also improves the purification yield of ethanol.

[0083] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for purifying ethanol from crude ethanol prepared from coal gasification methanol, characterized in that: The following steps are involved: S1, inputting the separation aid liquid at a temperature of 90-95° C. into the middle and upper part of the ethanol distillation tower (100) filled with aminated porous filler, and flowing from top to bottom in the ethanol distillation tower (100); S2, crude ethanol enters the interior of the ethanol distillation tower (100) from the feed pipe (101), the crude ethanol contacts and mixes with the separation aid liquid, the low boiling point molecules in the mixture are vaporized, and then continue to flow upward, the ethanol molecules are sampled from the ethanol side sampling pipe (102), the remaining gas molecules are discharged from the tower top discharge pipe (103), and the high boiling point molecules are mixed with the separation aid liquid and collected at the bottom of the ethanol distillation tower (100); S3. The separation aid liquid collected at the bottom of the ethanol distillation tower (100) is regenerated by a regeneration system coordinated with the ethanol distillation tower (100) and then enters the ethanol distillation tower (100) for recycling.

2. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 1, characterized in that: The ethanol distillation tower (100) has 100 plates. From bottom to top, the temperature of the first plate to the thirty-fifth plate is 110-120° C., the temperature of the thirty-fifth plate to the sixty-fifth plate is gradually reduced to 90-95° C., the temperature of the sixty-fifth plate to the eightieth plate is gradually reduced to 80-83° C., and the temperature of the eightieth plate to the hundredth plate is kept at 80-83° C. The operating pressure of the ethanol distillation tower (100) is 0.02-0.03 MPa.

3. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 1, characterized in that: One end of the feed pipe (101) extending into the interior of the ethanol distillation tower (100) is located at the top of the thirty-fifth tower plate layer, and one end of the ethanol side sampling pipe (102) extending into the interior of the ethanol distillation tower (100) is located at the top of the eightieth tower plate layer.

4. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 1, characterized in that: The auxiliary separation liquid is composed of ethylene glycol, dimethyl sulfoxide and 3-amino-1,2-propylene glycol in a volume ratio of 3:10:

2. The volume ratio of the auxiliary separation liquid and the crude ethanol product input into the ethanol distillation tower (100) is 3-5:

9.

5. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 1, characterized in that: The regeneration system comprises a shell-and-tube thin film evaporator (200), a connecting pipe 1 (104) installed at the input end of the shell-and-tube thin film evaporator (200), and a connecting pipe 2 (201) installed at the output end of the shell-and-tube thin film evaporator (200), the other end of the connecting pipe 1 (104) being in communication with the inner bottom of an ethanol distillation tower (100), a heat exchanger (202) being installed on the connecting pipe 2 (201), one end of the connecting pipe 2 (201) away from the shell-and-tube thin film evaporator (200) being in communication with the interior of the ethanol distillation tower (100), and the connecting pipe 2 (201) being located at the top of the sixty-fifth tower plate layer inside the ethanol distillation tower (100).

6. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 5, characterized in that: The operating temperature of the shell-and-tube thin film evaporator (200) is 145-150° C., and the pressure is normal pressure. The top of the shell-and-tube thin film evaporator (200) is provided with an air guide pipe connected to the condenser.

7. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 1, characterized in that: The preparation method of the aminated porous filler is as follows: the porous filler, anhydrous ethanol and 3-aminopropyltriethoxysilane are mixed, ultrasonically dispersed for 30-50 minutes, stirred, the temperature of the reaction system is increased to 50-60°C, ammonia water is added to the reaction system, the reaction is kept warm for 60-90 minutes, and post-processed to obtain the aminated porous filler.

8. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 7, characterized in that: The amount ratio of the porous filler, anhydrous ethanol, 3-aminopropyltriethoxysilane and ammonia water is 5g:50mL:2g:10mL, the mass fraction of the ammonia water is 5-8%, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven with a temperature of 70-80°C, and vacuum dried to constant weight to obtain an aminated porous filler.

9. The method for purifying crude ethanol prepared from coal gasification methanol according to claim 7, characterized in that: The porous filler is processed by the following steps: A1. Mix fly ash, cement, calcium hydroxide and cellulose to obtain a mixture; A2. Add deionized water to the mixture, stir evenly, and transfer it to a disc granulator for granulation to obtain a filler blank with a particle size of 5-8 mm; A3. Place the filler blank in an environment with a temperature of 45-55°C, cure for 5 days, and then calcine to obtain a porous filler.

10. The method for purifying ethanol from crude ethanol prepared from coal gasification methanol according to claim 9, characterized in that: In step A1, the weight ratio of fly ash, cement, calcium hydroxide and cellulose is 7-8: 0.9-1.3:2.1-2.5:1.2-1.5; in step A2, the dosage ratio of the mixture to deionized water is 10g:2-3mL; in step A3, the roasting temperature is 380-400°C, and the roasting time is 3-5h.

Images