Liquid phase adsorption nondestructive regeneration method for preparing electronic grade ethanol from industrial ethanol

Abstract

The invention discloses a liquid phase adsorption nondestructive regeneration method for preparing electronic grade ethanol from industrial ethanol, which achieves the purpose of obtaining an electronic grade ethanol product through the design and operation of heat exchange balance between a heating regeneration system and a cooling regeneration system and material balance of regenerated carrier gas. According to the invention, ethanol liquid-phase adsorption deep dehydration drying and zero circulation loss rate of regenerated carrier gas are realized, an adsorbent bed layer is regenerated completely and penetration is avoided, the water content of an electronic grade ethanol product produced by a liquid-phase adsorption system is ensured to reach the standard, and zero emission of organic matter ethanol in the whole liquid-phase adsorption process is realized.

Description

Technical Field

[0001] This invention belongs to the field of preparing electronic-grade ethanol by liquid-phase adsorption, drying and dehydration of industrial ethanol, and more specifically relates to a non-destructive regeneration method for preparing electronic-grade ethanol by liquid-phase adsorption of industrial ethanol. Background Technology

[0002] Electronic-grade ethanol (EGE) is a high-purity, colorless, and transparent organic solvent widely used in cleaning, electrolyte, and etching processes in electronic products such as semiconductors, photovoltaic solar cells, lithium batteries, and LED flat panel displays. As a cleaning agent, electrolyte, and organic solvent in the electronics industry, it is essential for cleaning chips and other electronic components during semiconductor and battery manufacturing. Lithium batteries require organic solvents as electrolytes to ensure high-quality electronic products. Therefore, electronic-grade ethanol must have a purity of 99.95% (w) or 99.99% (v) or higher. In China, anhydrous ethanol is defined by the national standard GB / T678-2023 as having a water content of less than or equal to 100 ppm and an acid content of no more than 0.001%. The Semiconductor Equipment and Materials International (SEMI) standard specifies a water content of less than or equal to 50 ppm.

[0003] Among the many methods for dehydrating and purifying anhydrous ethanol and electronic-grade ethanol from industrial ethanol synthesized with a water content of less than or equal to 5% (v) (GB6820-2016) or industrial alcohol fermented with a water content of less than or equal to 5% (v) (GB / T394.1-2008), liquid-phase adsorption is superior to other methods such as special distillation, pervaporation membrane, gas phase temperature and pressure swing adsorption (TSA / PSA), membrane adsorption combining gas phase adsorption and membrane separation, and adsorption distillation combining adsorption and distillation, due to its deep dehydration depth and high product yield. In particular, liquid-phase adsorption is currently one of the only methods that can achieve a dehydration depth of less than or equal to 10-50 ppmv of ethanol while maintaining good technical and economic efficiency. Although dehydration by pervaporation membrane or liquid-phase permeation membrane can also achieve this dehydration depth target, the flux of membrane separation is very small, and to achieve the same dehydration depth, more membrane area is required, which is expensive and has poor technical and economic efficiency.

[0004] Although the liquid-phase adsorption method for preparing electronic-grade ethanol from industrial ethanol has certain advantages, the depth of dehydration during liquid-phase adsorption is closely related to the desorption and regeneration process. First, due to the extremely low water pressure in liquid-phase adsorption and the high required dehydration depth, incomplete adsorbent regeneration can easily lead to penetration, resulting in substandard ethanol in the non-adsorbed phase. Second, for trace amounts of adsorbed water, the contradiction between adsorption and desorption is even more pronounced. The more favorable the adsorption, for example, to achieve a dehydration depth of 50 ppm, the lower the adsorption temperature needs to be. However, the lower the adsorption temperature, the more difficult desorption becomes, requiring more regeneration energy and a longer regeneration time. This leads to a poorer match between adsorption and desorption cycles, sometimes necessitating more adsorption towers to maintain the necessary steps for desorption and to complete the cycle, increasing investment costs. Third, the mass transfer process in liquid-phase adsorption is greatly affected by heat transfer. The large difference between endothermic and exothermic heat during the adsorption and desorption cycles, often with a lag, makes... The large temperature difference within the adsorption tower significantly impacts mass transfer. Therefore, the regeneration carrier gas, regeneration temperature, and regeneration process during desorption and regeneration aim to minimize temperature fluctuations during the cyclic operation within the adsorption tower, ensuring a perfect match between adsorption and desorption cycles. Fourth, in liquid-phase adsorption, adsorbed moisture accumulates in the adsorbent bed, particularly at the bottom. During desorption and regeneration, the different flow directions of the regeneration carrier gas often lead to the re-adsorption of desorbed moisture by the upper adsorbent layer, resulting in incomplete desorption and regeneration. Fifth, the regeneration carrier gas load required for liquid-phase adsorption is significantly higher than that for gas-phase adsorption, leading to a higher loss rate of regeneration carrier gas during the cyclic operation, resulting in substantial heat load losses. In summary, the desorption and regeneration method is crucial for achieving effective production of electronic-grade ethanol in the liquid-phase adsorption process. Therefore, this invention employs the following technical solution to address the desorption and regeneration challenges of liquid-phase adsorption for electronic-grade ethanol:

[0005] A non-destructive regeneration method for preparing electronic-grade ethanol from industrial ethanol via liquid-phase adsorption is characterized by the following steps: Industrial ethanol with a concentration of 20-60% is fed into a distillation column for concentration. Water flows out from the bottom of the column and is discharged, while ethanol vapor, representing an ethanol-water binary azeotrope, flows out from the top. The ethanol concentration is 95%, the water content is 5%, the temperature is 70-90℃, and the pressure is 0.01-0.3 MPa. Alternatively, the vapor can be condensed and cooled before entering an intermediate product unit composed of a liquid-phase permeation membrane to obtain an anhydrous ethanol with a water content of 200-600 ppm. Alternatively, the ethanol vapor can be heated to 90-130℃ and then entered into an intermediate product unit composed of gas-phase pressure swing adsorption to obtain an anhydrous ethanol with a water content of 200-500 ppm. Ethanol, an intermediate product from the intermediate product unit, either directly or after being cooled to 60–90°C, enters a heating and regeneration system consisting of three adsorption towers (labeled A, B, and C) loaded with adsorbent, corresponding programmable valve groups, pipelines, and a heating and regeneration system consisting of an electric heater for online heating of the adsorbent bed, a steam heater, a regeneration carrier gas feed, and corresponding pipelines and control valves; a cooling and regeneration system consisting of a circulating liquid tank for online cooling of the adsorbent bed, a cooler, a regeneration gas-liquid separator, a circulating liquid compressor, a circulating dryer, a dilute phase circulating pump, a balance gas feed, and corresponding pipelines and control valves; and pipelines connecting the upper and lower inlet and outlet flows of the adsorption towers and the heating and regeneration systems. The liquid phase adsorption and desorption regeneration unit, composed of switching connection pipelines, performs liquid phase adsorption dehydration and desorption regeneration. Each adsorption tower successively performs adsorption, heating regeneration, cooling regeneration, rinsing, and sequential discharge / final charging steps. Specifically, the intermediate product enters from the bottom of one of the adsorption towers, A, for adsorption. The water in the intermediate product is adsorbed by the adsorbent loaded in adsorption tower A. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower A is less than or equal to 50-100 ppmv, and it is output as electronic-grade ethanol product into the electronic-grade ethanol product storage tank. After the adsorption step in adsorption tower A, the intermediate product entering the bottom of adsorption tower A is automatically switched off by a program control valve and transferred to adsorption tower B, entering from the bottom of adsorption tower B to continue adsorption dehydration. The moisture in the intermediate product is adsorbed by the adsorbent loaded in adsorption tower B. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower B is less than or equal to 50-100 ppmv. This is then continuously output as electronic-grade ethanol into the electronic-grade ethanol product tank. After the adsorption step is completed in adsorption tower B, the intermediate product at the bottom of adsorption tower B is automatically switched off by a programmable control valve and transferred to adsorption tower C. It then continuously undergoes adsorption and dehydration from the bottom of adsorption tower C. The moisture in the intermediate product is adsorbed by the adsorbent loaded in adsorption tower C. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower C is less than or equal to 50-100 ppmv. This is then continuously output as electronic-grade ethanol into the electronic-grade ethanol product tank. When adsorption tower C completes the adsorption step...The intermediate product entering the bottom of adsorption tower C is automatically switched off by a programmable control valve and transferred to adsorption tower A, where it enters from the bottom for a new adsorption cycle, thus ensuring the continuous production of electronic-grade ethanol. During the adsorption time in adsorption tower A, one of the adsorption towers, B, undergoes regeneration cooling, rinsing, and final charging steps sequentially, while adsorption tower C undergoes desorption regeneration after adsorption is complete, involving heating and regeneration. Specifically, after adsorption tower C stops adsorption, the electronic-grade ethanol product outlet valve is immediately closed, and the forward discharge valve is opened to perform forward discharge final charging on adsorption tower B, which is in the forward discharge final charging step. This is to allow a small amount of regeneration carrier gas remaining in adsorption tower B to be discharged and to bring adsorption tower B to the operating temperature and pressure required for the next adsorption step, preparing it for subsequent adsorption. During this process, if the forward discharge liquid supplied from adsorption tower C is insufficient, it is supplemented with either intermediate product or electronic-grade ethanol. After the initial flow of column B is completed, a heating regeneration carrier gas, heated to 160-250°C by ambient nitrogen gas heated by an electric heating and steam heater in the heating regeneration system, is introduced from the top of the column for heating regeneration. This process desorbs the water adsorbed on the adsorbent, thus regenerating the adsorbent. After heating regeneration, the hot regeneration gas flowing out from the bottom passes through a circulating liquid tank, cooler, regeneration gas-liquid separator, ambient nitrogen balance gas, circulating compressor, circulating dryer, and dilute phase circulating pump for heat exchange, gas-liquid separation, and drying of the circulating regeneration carrier gas. The water-enriched dilute phase obtained from the bottom of the gas-liquid separator is returned to the distillation column via the dilute phase circulating pump for further recovery of ethanol from the dilute phase. The nitrogen regeneration gas flowing out from the top of the gas-liquid separator... After further drying by a nitrogen circulating compressor and a circulating dryer, the nitrogen regeneration carrier gas is recycled and reused. It is then heated to 160–250°C and returned to the adsorption tower undergoing heating regeneration for further heating and regeneration. Simultaneously, unheated nitrogen regeneration carrier gas, or nitrogen regeneration carrier gas after heat exchange with the heated regeneration gas, is introduced into adsorption tower B, which is in the cooling regeneration and rinsing stage, for cooling regeneration and rinsing. The resulting rinsing waste gas undergoes heat exchange and gas-liquid separation via a circulating liquid tank, cooler, and regeneration gas-liquid separator. A portion of the ambient temperature nitrogen regeneration carrier gas directly enters the circulating liquid tank as a balancing gas to prevent the release of ethanol or other pollutants. Water escapes in a gaseous phase, disrupting the liquid level and volume of the circulating liquid tank. The water-enriched dilute phase obtained from the bottom of the gas-liquid separator is returned to the distillation column via a dilute phase circulation pump for further recovery of ethanol from the dilute phase. Nitrogen regeneration gas flows from the top of the gas-liquid separator. After further drying by a nitrogen circulation compressor and circulation dryer, it is used as nitrogen regeneration carrier gas. Alternatively, it is heated to 160–250°C and returned to the adsorption tower undergoing heating regeneration for heating regeneration. Or, it is used as regeneration carrier gas and flushing gas in the adsorption tower undergoing cooling regeneration and flushing stages. The nitrogen regeneration carrier gas is recycled. After cooling regeneration and flushing are completed in adsorption tower B, it undergoes a final charge in the forward direction, preparing it for the next round of adsorption steps.After adsorption tower A completes its adsorption step, its electronic-grade ethanol product outlet valve and intermediate product feed valve are closed. Immediately, the system automatically switches and opens the electronic-grade ethanol product outlet valve and intermediate product feed valve of adsorption tower B. Adsorption tower B then enters its adsorption step, while adsorption tower A enters its heating regeneration step. Adsorption tower C subsequently enters its cooling regeneration, rinsing, and final charging steps, thus continuously producing electronic-grade ethanol product with a yield greater than or equal to 99%. Furthermore, the nitrogen regeneration carrier gas is recycled, resulting in zero loss and achieving non-destructive regeneration of the liquid phase adsorption.

[0006] Furthermore, in the aforementioned non-destructive regeneration method for preparing electronic-grade ethanol from industrial ethanol via liquid-phase adsorption, the liquid-phase adsorption and desorption regeneration unit, composed of the inlet and outlet pipelines connecting the upper and lower parts of the adsorption tower and the switching pipelines for the heating and cooling regeneration systems, allows the heating or cooling regeneration carrier gas to be introduced into the adsorption tower for regeneration from top to bottom, from bottom to top, or alternately from top to bottom and from bottom to top, thereby ensuring complete desorption and regeneration of the adsorbent bed within the adsorption tower.

[0007] Furthermore, in the aforementioned non-destructive regeneration method for preparing electronic-grade ethanol by liquid-phase adsorption of industrial ethanol, the regeneration carrier gas, rinsing, and final charging steps in the adsorption and desorption cycle are all replaced by electronic-grade ethanol products instead of nitrogen, efflux liquid, or intermediate products. The efflux step is eliminated, and the nitrogen circulating compressor, dryer, and regeneration gas-liquid separator are also eliminated. All circulating liquid generated from the circulating liquid tank is returned to the distillation column, and the corresponding desorption and regeneration operation temperature is less than 200°C. As a result, the obtained electronic-grade ethanol product has a water content of less than or equal to 10-50 ppmv. Under these conditions, the direction of the heating and cooling regeneration ethanol carrier gas entering the adsorption column is limited to top to bottom.

[0008] Furthermore, the aforementioned non-destructive regeneration method for liquid-phase adsorption in the preparation of electronic-grade ethanol from industrial ethanol includes an adsorption and desorption regeneration system comprising four adsorption towers loaded with adsorbent. Two towers are in the adsorption step, one tower is in the heating regeneration step, and one tower is in the cooling regeneration, rinsing, and desorption / final charging desorption regeneration step. The two towers in the adsorption step may simultaneously or alternately undergo the desorption step to match the other two towers in the desorption / final charging desorption regeneration step. The desorbed liquid meets the demand of the towers in the desorption / final charging step. Under this condition, the adsorption capacity is increased by 15-25% compared to the three-tower operation mode.

[0009] Furthermore, in the aforementioned non-destructive regeneration method for preparing electronic-grade ethanol from industrial ethanol via liquid-phase adsorption, the raw material liquid is finished industrial-grade ethanol, i.e., industrial ethanol synthesized with a water content of less than or equal to 5% (v) or industrial alcohol fermented with a water content of less than or equal to 5% (v). The industrial-grade ethanol raw material stream is transported directly into the intermediate product unit via a raw material pump at a temperature of 20–80°C and a pressure of atmospheric or low pressure. After obtaining the intermediate product, it enters the adsorption and desorption regeneration unit to obtain electronic-grade ethanol with a water content of less than or equal to 50–100 ppmv. The water-enriched dilute phase obtained from the regeneration gas-liquid separator is mixed with the water-enriched dilute phase obtained from the intermediate product unit and transported via a dilute phase circulation pump to a newly added post-distillation column. The ethanol-water azeotrope ethanol vapor flowing out from the top of the distillation column is treated and mixed with the raw material liquid before entering the intermediate product unit for further ethanol recovery. Water flows out from the bottom of the distillation column and is discharged.

[0010] Compared with the prior art, the main advantages of the present invention are:

[0011] (1) During the desorption and regeneration process of the adsorbent bed in the adsorption tower, the loss rate of nitrogen or electronic grade ethanol products as regeneration carrier gas is basically zero. At the same time, the adsorbent bed can be completely regenerated, avoiding penetration, ensuring that the water content of the electronic grade ethanol products produced by the liquid phase adsorption system meets the standard, and the organic ethanol in the entire liquid phase adsorption process is zero-emission.

[0012] (2) The heating regeneration carrier gas or cooling regeneration carrier gas can be introduced into the adsorption tower for regeneration from top to bottom or from bottom to top, or alternately from top to bottom or from bottom to top, through the upper and lower inlet and outlet material pipelines of the adsorption tower and the switching connection pipelines for the heating regeneration system and the cooling regeneration system, so as to ensure the complete desorption and regeneration of the adsorbent bed in the adsorption tower.

[0013] (3) By using electronic-grade ethanol products as the medium for regeneration, rinsing, and final charging, this invention further reduces the operating temperature of desorption regeneration. It can produce electronic-grade ethanol products that meet the strict standards of the Semiconductor Equipment and Materials International (SEMI), with a dehydration depth of up to 10 ppm, exceeding the SEMI standard of 50 ppm. It can also significantly reduce the equipment investment and energy consumption of the desorption regeneration system.

[0014] (4) The present invention can switch the 3-tower operation process in the adsorption and desorption regeneration process to a 4-tower operation process, which can improve the processing capacity and ensure the complete regeneration of the adsorbent bed. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the process in Example 1.

[0016] Figure 2 This is a schematic diagram of the process in Example 2.

[0017] Figure 3 This is a schematic diagram of the process in Example 3. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0019] Example 1

[0020] like Figure 1As shown, a non-destructive regeneration method for preparing electronic-grade ethanol via liquid-phase adsorption from industrial ethanol is described. 25% industrial ethanol is used as the feed liquid and fed into a distillation column for concentration. Water flows out from the bottom of the column and is discharged, while ethanol vapor, representing an ethanol-water binary azeotrope, flows out from the top. The ethanol concentration is 95%, the water content is 5%, the temperature is 70–90°C, and the pressure is 0.03–0.04 MPa. The ethanol vapor, heated to 90–130°C, enters an intermediate product unit composed of gas-phase pressure swing adsorption to obtain an anhydrous ethanol intermediate product with a water content of 200–300 ppm. The intermediate product from the intermediate product unit is then... The liquid, cooled to 60–90°C, enters a liquid-phase adsorption and desorption regeneration unit consisting of three adsorption towers (A, B, and C, respectively) loaded with adsorbent, corresponding programmable valve groups, pipelines, and heating and cooling regeneration systems. During operation, the switching valves on the inlet and outlet pipelines of the heating and cooling regeneration systems are closed. The intermediate product enters from the bottom of adsorption tower A for adsorption. The water in the intermediate product is adsorbed by the adsorbent in adsorption tower A. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower A is less than or equal to 50–100%. The intermediate product, with a concentration of 00 ppmv, is output as electronic-grade ethanol and enters the electronic-grade ethanol product storage tank. After the adsorption step in adsorption tower A, the intermediate product at the bottom of adsorption tower A is automatically switched off by a programmable control valve and transferred to adsorption tower B, where it continues to undergo adsorption and dehydration from the bottom. The water in the intermediate product is adsorbed by the adsorbent loaded in adsorption tower B. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower B is less than or equal to 50-100 ppmv. This intermediate product continues to be output as electronic-grade ethanol and enters the electronic-grade ethanol product tank. After the adsorption step in adsorption tower B is completed, the intermediate product at the bottom of adsorption tower B passes through a process... The sequential control valve automatically switches to stop the feed and transfers the product to adsorption tower C. The intermediate product enters adsorption tower C from the bottom for continuous adsorption and dehydration. The water in the intermediate product is adsorbed by the adsorbent loaded in adsorption tower C. The water content in the non-adsorbed phase fluid flowing out from the top of adsorption tower C is less than or equal to 50-100 ppmv. This is continuously output as electronic-grade ethanol into the electronic-grade ethanol product tank. After adsorption tower C completes its adsorption step, the intermediate product entering the bottom of adsorption tower C is automatically switched to stop by the program control valve and transferred to adsorption tower A from the bottom for a new adsorption cycle. This ensures the continuous production of electronic-grade ethanol. During the adsorption time in adsorption tower A, one of the adsorption towers, B, undergoes regeneration cooling, rinsing, and final charging steps sequentially. One of the adsorption towers, C, undergoes desorption regeneration (heat regeneration) after adsorption is complete. That is, after adsorption tower C stops its adsorption step, the electronic-grade ethanol product outlet valve is immediately closed, and the forward discharge valve is opened to perform forward discharge final charging of adsorption tower B, which is in the forward discharge final charging step.The purpose is to remove a small amount of regeneration carrier gas retained in adsorption tower B and to bring adsorption tower B to the operating temperature and pressure required for the adsorption step, preparing it for subsequent adsorption. During this process, if the effluent from adsorption tower C is insufficient, it can be supplemented with intermediate products or electronic-grade ethanol. After the effluent from adsorption tower B is complete, heated regeneration carrier gas (heated to 200-220°C by electric heating and steam heating in the regeneration system) is introduced from the top of the tower for regeneration. This process desorbs the hydrolysate adsorbed onto the adsorbent, thus regenerating the adsorbent. The hot regeneration gas flowing from the bottom after regeneration passes through a circulating liquid tank, cooler, regeneration gas-liquid separator, ambient temperature nitrogen balance gas, and circulating compressor. A circulating dryer and a dilute phase circulating pump perform heat exchange, gas-liquid separation, and drying of the regenerated carrier gas. The water-enriched dilute phase obtained from the bottom of the gas-liquid separator is returned to the distillation column via the dilute phase circulating pump for further recovery of ethanol from the dilute phase. The nitrogen regeneration gas flowing out from the top of the gas-liquid separator is further dried by a nitrogen circulating compressor and a circulating dryer, and then used as nitrogen regeneration carrier gas for recycling. After being heated to 200-220°C by a heater, it is returned to the adsorption tower undergoing heating regeneration for further heating regeneration. The nitrogen regeneration carrier gas is thus recycled. Simultaneously, unheated nitrogen regeneration carrier gas or nitrogen regeneration carrier gas that has undergone heat exchange with the heated regeneration gas is introduced into adsorption tower B, which is in the cooling regeneration and rinsing stage, for cooling regeneration and rinsing. The flushing exhaust gas undergoes heat exchange and gas-liquid separation in a circulating liquid tank, cooler, and regeneration gas-liquid separator. A portion of the ambient temperature nitrogen regeneration carrier gas is directly introduced into the circulating liquid tank as a balancing gas, preventing some ethanol or water from escaping in the gaseous phase and disrupting the tank's level and volume. The water-rich dilute phase obtained from the bottom of the gas-liquid separator is returned to the distillation column via a dilute phase circulation pump for further ethanol recovery. The nitrogen regeneration gas flowing from the top of the gas-liquid separator is further dried by a nitrogen circulation compressor and circulation dryer, and then used as nitrogen regeneration carrier gas. Alternatively, it can be heated to 200–220°C and returned to the adsorption tower undergoing heating regeneration, or used as regeneration carrier gas and flushing gas for cooling regeneration and returned to the adsorption tower undergoing cooling regeneration. In the cooling, regeneration, and rinsing stages of the adsorption tower, the nitrogen regeneration carrier gas is recycled. After adsorption tower B completes cooling, regeneration, and rinsing, it undergoes a final purging in the forward direction, preparing it for the next adsorption step. When adsorption tower A completes its adsorption step, its electronic-grade ethanol product outlet valve and intermediate product feed valve are closed. Immediately afterward, the electronic-grade ethanol product outlet valve and intermediate product feed valve of adsorption tower B are automatically switched and opened, and adsorption tower B enters the adsorption step. Simultaneously, adsorption tower A enters the heating regeneration step, while adsorption tower C successively enters the cooling, regeneration, rinsing, and final purging steps. This continuously yields electronic-grade ethanol product with a yield greater than or equal to 99%. Furthermore, the nitrogen regeneration carrier gas is recycled, resulting in zero loss, achieving non-destructive regeneration of liquid-phase adsorption.

[0021] Example 2

[0022] like Figure 2 As shown, a non-destructive regeneration method for preparing electronic-grade ethanol from industrial ethanol via liquid-phase adsorption is described. In the adsorption and desorption cycle operation, the regeneration carrier gas, rinsing, and final charging steps all use electronic-grade ethanol products to replace nitrogen, effluent, or intermediate products, eliminating the effluent step and eliminating the nitrogen circulation compressor, dryer, and regeneration gas-liquid separator. All circulating liquid generated from the circulating liquid tank is returned to the distillation column, and the corresponding desorption and regeneration operation temperature is less than 200°C. As a result, the obtained electronic-grade ethanol product has a water content of less than or equal to 10-50 ppmv. Under these conditions, the direction of the heating regeneration and cooling regeneration ethanol carrier gas entering the adsorption column is limited to top to bottom.

[0023] Example 3

[0024] like Figure 3 As shown, a non-destructive regeneration method for preparing electronic-grade ethanol from industrial ethanol via liquid-phase adsorption is disclosed. The raw material is purchased finished industrial-grade ethanol, i.e., the water content in the ethanol is less than or equal to 5% (v). The industrial-grade ethanol raw material stream is transported directly into the intermediate product unit via a raw material pump at a temperature of 20-80℃ and a pressure of atmospheric or low pressure. After obtaining the intermediate product, it enters the adsorption and desorption regeneration unit to obtain electronic-grade ethanol with a water content of less than or equal to 50-100 ppmv. The water-enriched dilute phase obtained from the regeneration gas-liquid separator is mixed with the water-enriched dilute phase obtained from the intermediate product unit and transported to a newly added post-distillation column via a dilute phase circulation pump. The ethanol-water azeotrope vapor flowing out from the top of the distillation column is treated and mixed with the raw material before entering the intermediate product unit for further ethanol recovery. Water flows out from the bottom of the distillation column and is discharged.

[0025] Obviously, the embodiments described above are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments described in this invention, all other embodiments obtained by those skilled in the art without creative effort, or structural changes made under the guidance of this invention, that have the same or similar technical solutions as this invention, all fall within the protection scope of this invention.

Claims

1. A method for lossless regeneration of liquid phase adsorption of electronic grade ethanol from industrial ethanol, characterized in that, The industrial ethanol with concentration of 20-60% as raw material liquid enters a rectifying column for concentration, water is discharged from the bottom of the rectifying column, ethanol-water binary azeotrope ethanol vapor is discharged from the top of the rectifying column, the concentration of ethanol is 95%, the water content is 5%, the temperature is 70-90℃, and the pressure is 0.01-0.3MPa, or the ethanol vapor is cooled and condensed to enter an intermediate product unit composed of a liquid phase permeation membrane to obtain an intermediate product of anhydrous ethanol with water content of 200-600ppm, or the ethanol vapor is heated to 90-130℃ to enter an intermediate product unit composed of a gas phase pressure swing adsorption to obtain an intermediate product of anhydrous ethanol with water content of 200-500ppm, the intermediate product produced by the intermediate product unit, or the liquid directly or after being cooled to 60-90℃, enters a liquid phase adsorption and desorption regeneration unit composed of three adsorption columns A, B and C loaded with adsorbents, corresponding program control valve groups, pipelines, a heating regeneration system composed of an electric heater, a steam heater, a regenerative carrier gas feeding and corresponding pipelines and control valve groups for online heating and regenerating the adsorbent bed by the regenerative carrier gas, a cooling regeneration system composed of a circulating liquid tank, a cooler, a regenerative gas-liquid separator, a circulating liquid compressor, a circulating dryer, a dilute phase circulating pump, a balance gas feeding and corresponding pipelines and control valve groups for online cooling and regenerating the adsorbent bed by the circulating liquid, and switching pipelines connecting the inlet and outlet flow pipelines of the adsorption columns and the inlet and outlet flow of the heating regeneration system and the cooling regeneration system, to carry out liquid phase adsorption dehydration and desorption regeneration, each adsorption column successively carries out adsorption, heating regeneration, cooling regeneration, flushing and order release / terminal filling steps, the specific process is that the intermediate product enters one of the adsorption columns A from the bottom to carry out adsorption, the water in the intermediate product is adsorbed by the adsorbent loaded in the adsorption column A, the water content in the non-adsorbed phase fluid discharged from the top of the adsorption column A is less than or equal to 50-100ppmv, which is output as an electronic grade ethanol product into an electronic grade ethanol product tank, after the adsorption step of the adsorption column A, the intermediate product entering the bottom of the adsorption column A is automatically switched to stop feeding by the program control valve to enter the adsorption column B and continue to carry out adsorption dehydration from the bottom of the adsorption column B, the water in the intermediate product is adsorbed by the adsorbent loaded in the adsorption column B, the water content in the non-adsorbed phase fluid discharged from the top of the adsorption column B is less than or equal to 50-100ppmv, which is continuously output as an electronic grade ethanol product into an electronic grade ethanol product tank, after the adsorption step of the adsorption column B is completed, the intermediate product entering the bottom of the adsorption column B is automatically switched to stop feeding by the program control valve to enter the adsorption column C and continuously carry out adsorption dehydration from the bottom of the adsorption column C, the water in the intermediate product is adsorbed by the adsorbent loaded in the adsorption column C, the water content in the non-adsorbed phase fluid discharged from the top of the adsorption column C is less than or equal to 50-100ppmv, which is continuously output as an electronic grade ethanol product into an electronic grade ethanol product tank, when the adsorption step of the adsorption column C is completed,The intermediate product entering the bottom of the adsorption tower C is automatically switched off by the program control valve and transferred to the adsorption tower A and enters the bottom of the adsorption tower A to start a new adsorption cycle, thus ensuring the continuous production of the electronic grade ethanol product. During the adsorption of the adsorption tower A, one of the adsorption towers B is in the steps of regeneration cooling, flushing and final charging in turn, and one of the adsorption towers C is in the step of heating and desorption regeneration after the adsorption is completed, that is, after the adsorption tower C stops the adsorption step, the electronic grade ethanol product outlet valve is closed and the order discharge valve is opened to discharge the adsorption tower B in the order discharge final charging step, the purpose is to make the adsorption tower B discharge a small amount of regeneration carrier gas and make the adsorption tower B reach the operating temperature and pressure of the adsorption step, to prepare for the next adsorption, during which, if the order discharge liquid from the adsorption tower C is not enough, or the intermediate product or the electronic grade ethanol product is used to supplement, after the adsorption tower B completes the order discharge, the heating regeneration carrier gas heated by the electric heater and the steam heater in the heating regeneration system is introduced from the top of the adsorption tower B to heat the regeneration carrier gas with a temperature of 160-250℃, the hydrolysis adsorbed on the adsorbent is desorbed, and the adsorbent is regenerated, the hot regeneration gas flowing out from the bottom of the adsorption tower B after heating regeneration is subjected to heat exchange, gas-liquid separation and drying of the circulating regeneration carrier gas through the circulating liquid tank, cooler, regeneration gas-liquid separator, normal temperature nitrogen balance gas, circulating compressor, circulating dryer and dilute phase circulating pump, the dilute phase rich in water obtained from the bottom of the gas-liquid separator is returned to the rectifying tower through the dilute phase circulating pump to further recover the ethanol in the dilute phase, the nitrogen regeneration gas flowing out from the top of the gas-liquid separator is further dried by the nitrogen circulating compressor and the circulating dryer, and is used as the nitrogen regeneration carrier gas, and is heated to 160-250℃ by the heater and returned to the adsorption tower in the heating regeneration to perform heating regeneration, the nitrogen regeneration carrier gas is recycled, at the same time, the unheated nitrogen regeneration carrier gas or the nitrogen regeneration carrier gas after heat exchange with the heating regeneration gas is introduced into the adsorption tower B in the cooling regeneration and flushing stage to perform cooling regeneration and flushing, the flushing waste gas is subjected to heat exchange and gas-liquid separation through the circulating liquid tank, cooler and regeneration gas-liquid separator, wherein a part of the normal temperature nitrogen regeneration carrier gas is directly introduced into the circulating liquid tank as a balance gas to prevent part of the ethanol or water from escaping in gas phase to destroy the liquid level and volume of the circulating liquid tank, the dilute phase rich in water obtained from the bottom of the gas-liquid separator is returned to the rectifying tower through the dilute phase circulating pump to further recover the ethanol in the dilute phase, the nitrogen regeneration gas flowing out from the top of the gas-liquid separator is further dried by the nitrogen circulating compressor and the circulating dryer, and is used as the nitrogen regeneration carrier gas, or is heated to 160-250℃ by the heater and returned to the adsorption tower in the heating regeneration to perform heating regeneration, or is returned to the adsorption tower in the cooling regeneration and flushing stage as the cooling regeneration carrier gas and flushing gas, the nitrogen regeneration carrier gas is recycled, after the adsorption tower B completes the cooling regeneration and flushing, the order discharge final charging is performed to make it in the next adsorption step state.When the adsorption tower A completes the adsorption step, its electronic grade ethanol product outlet valve and intermediate product feeding valve are closed, and the electronic grade ethanol product outlet valve and intermediate product feeding valve of the adsorption tower B are automatically switched and opened immediately, the adsorption tower B enters the adsorption step, while the adsorption tower A enters the heating regeneration step, and the adsorption tower C enters the cooling regeneration, flushing and desorption final filling steps in turn, thereby continuously obtaining the electronic grade ethanol product with a yield greater than or equal to 99%, and the nitrogen regeneration carrier gas is recycled, and its loss rate is zero, realizing lossless regeneration of liquid phase adsorption.

2. A method for lossless regeneration of liquid phase adsorption of electronic grade ethanol from industrial ethanol as claimed in claim 1, wherein, The liquid phase adsorption and desorption regeneration unit is composed of the upper and lower inlet and outlet flow lines of the connecting adsorption tower, and the switching connection lines of the inlet and outlet flows of the heating regeneration system and the cooling regeneration system. The heating regeneration carrier gas or the cooling regeneration carrier gas can be introduced into the adsorption tower from top to bottom for regeneration, or from bottom to top for regeneration, or alternately from top to bottom and from bottom to top for regeneration, so as to ensure the complete desorption and regeneration of the adsorbent bed in the adsorption tower.

3. A method for lossless regeneration of liquid phase adsorption of electronic grade ethanol from industrial ethanol as claimed in claim 1, wherein, In the adsorption and desorption cycle operation, the regeneration carrier gas, flushing and final charging steps are replaced by electronic grade ethanol product instead of nitrogen, order liquid or intermediate product, the order step is cancelled, and the nitrogen circulation compressor, dryer and regeneration gas-liquid separator are cancelled. The circulating liquid generated from the circulating liquid tank is returned to the rectification tower, and the corresponding desorption and regeneration operation temperature is less than 200℃. Thus, the electronic grade ethanol product obtained has a water content of less than or equal to 10-50ppmv. In this case, the direction of the heating regeneration and cooling regeneration ethanol carrier gas introduced into the adsorption tower is limited to from top to bottom.

4. A method for lossless regeneration of liquid phase adsorption of electronic grade ethanol from industrial ethanol as claimed in claim 1, wherein, The adsorption and desorption regeneration system includes four adsorption towers loaded with adsorbent, of which two adsorption towers are in the adsorption step, one adsorption tower is in the heating regeneration step, and one adsorption tower is in the cooling regeneration, flushing and order / terminal charging desorption regeneration step. The two adsorption towers in the adsorption step perform the order step simultaneously or alternately to match the other two adsorption towers in the order / terminal charging desorption regeneration step. The order liquid meets the demand of the adsorption tower in the order / terminal charging step. Under this condition, the adsorption treatment capacity is increased by 15-25% compared with the 3-tower operation mode.

5. A method for lossless regeneration of liquid phase adsorption of electronic grade ethanol from industrial ethanol as claimed in claim 1, wherein, The raw material liquid is finished industrial grade ethanol, i.e. industrial ethanol synthesized with a water content of less than or equal to 5%(v) or industrial alcohol fermented with a water content of less than or equal to 5%(v). The industrial grade ethanol raw material stream has a temperature of 20-80℃ and a pressure of normal pressure or low pressure, is delivered by a raw material pump, directly enters the intermediate product unit and obtains an intermediate product, and then enters the adsorption and desorption regeneration unit to obtain an electronic grade ethanol product with a water content of less than or equal to 50-100ppmv. The dilute phase rich in water obtained from the regeneration gas-liquid separator is mixed with the dilute phase rich in water obtained from the intermediate product unit, and is delivered by a dilute phase circulating pump to a newly added post rectification tower. The ethanol-water azeotrope ethanol vapor flowing out of the rectification tower top is treated and mixed with the raw material liquid to enter the intermediate product unit for further recovery of ethanol, and water flows out of the rectification tower bottom. ​

Images