Recovery apparatus for isopropanol and cellulose production system

Abstract

The application discloses a recovery device for isopropyl alcohol, which comprises a liquid supply assembly, a first evaporator, a demisting mechanism, a separation mechanism, a first condenser and a second evaporator. The first evaporator is connected with the liquid supply assembly; the demisting mechanism is connected with a gas phase outlet of the first evaporator; the separation mechanism is connected with the demisting mechanism; the first condenser is connected with the separation mechanism; the second evaporator is connected with a liquid phase outlet of the first evaporator, and a gas phase outlet of the second evaporator is connected with the separation mechanism. The residual liquid generated by the first evaporator can be evaporated again by the second evaporator with a higher evaporation rate, so that the isopropyl alcohol in the residual liquid is collected while the solid phase material is removed, the isopropyl alcohol wasted with the solid phase material is effectively reduced, and the recovery rate of the isopropyl alcohol is improved. In addition, the solid phase material is a cellulose product, which can be collected after being separated from the isopropyl alcohol solution, so as to avoid being wasted, and the yield of the cellulose product is improved.

Description

Technical Field

[0001] This application belongs to the technical field of cellulose preparation equipment, specifically relating to a device for isopropanol recovery and a cellulose preparation system. Background Technology

[0002] In the preparation of certain functional cellulose products, isopropanol solution is typically used for the reaction. After the reaction, purified isopropanol (isopropanol content ≥98%) may be used to purify the cellulose product and clean the reaction vessel. To avoid isopropanol waste, a recovery system is usually installed to recover the reaction solution (isopropanol solution), the purified solution (purified isopropanol), and the cleaning solution (purified isopropanol).

[0003] Solid cellulose products are typically present in reaction solutions, purification solutions, and washing solutions. Existing devices for recovering isopropanol waste liquid containing solid impurities usually involve filtering the waste liquid first. For example, in patent CN113943209B, for the recovery of isopropanol waste liquid containing solid impurities after semiconductor cleaning, the isopropanol waste liquid is first filtered to remove solid impurities. This patent uses a filter to remove solid impurities, but when too much solid impurity accumulates in the filter, it needs to be cleaned. During cleaning, some isopropanol may be discharged along with the solid impurities, affecting the isopropanol recovery rate. Utility Model Content

[0004] The technical problem to be solved by this application is that existing isopropanol recovery devices use filters to filter solid impurities. When cleaning solid impurities, isopropanol is discharged along with the solid impurities, which affects the recovery rate of isopropanol. In order to solve this technical problem, an isopropanol recovery device and cellulose preparation system that can improve the recovery rate of isopropanol are provided.

[0005] The technical solution proposed in this application is as follows:

[0006] An apparatus for recovering isopropanol, comprising:

[0007] Liquid supply assembly for conveying waste liquid;

[0008] The first evaporator, connected to the liquid supply assembly, is used to evaporate the waste liquid to form gaseous substances and residual liquid.

[0009] A demisting mechanism is connected to the gas phase outlet of the first evaporator and is used to remove impurities from the gas phase substance;

[0010] A separation mechanism, connected to the demisting mechanism, is used to separate isopropanol and water from gaseous substances;

[0011] The first condenser, connected to the separation mechanism, is used to condense isopropanol;

[0012] The second evaporator is connected to the liquid phase outlet of the first evaporator and is used to evaporate the residual liquid to form solid and gaseous substances.

[0013] The second evaporator has a higher evaporation rate than the first evaporator, and the gas phase outlet of the second evaporator is connected to the separation mechanism.

[0014] Using the aforementioned isopropanol recovery device, the first evaporator evaporates the waste liquid, forming a gaseous substance and residual liquid. A demister removes impurities entrained in the gaseous substance, which then enters a separation mechanism. The residual liquid from the first evaporator is fed into a second evaporator for further evaporation, producing a gaseous substance that enters the separation mechanism. The separation mechanism separates the gaseous isopropanol from water vapor, and the gaseous isopropanol is fed into a first condenser to form liquid isopropanol, which is then collected. Because the residual liquid from the first evaporator can be further evaporated in the second evaporator with a higher evaporation rate, the isopropanol in the residual liquid can be collected, effectively reducing the waste of isopropanol discharged with the solid phase and improving the isopropanol recovery rate. Furthermore, the solid phase is a cellulose product, which can be collected after separation from the isopropanol solution, preventing waste and thus increasing the yield of the cellulose product.

[0015] Furthermore, the first evaporator is a horizontal evaporator, and the second evaporator is a scraped evaporator.

[0016] Furthermore, it also includes a preheating mechanism, which is connected to the liquid supply assembly and is used to preheat the waste liquid.

[0017] Furthermore, the preheating mechanism is the first condenser, which is a heat exchanger; the heat exchanger includes a shell side and a tube side, the shell side is connected to the separation mechanism, and the tube side is connected to the liquid supply assembly.

[0018] Furthermore, the separation mechanism includes a separation membrane assembly, a second condenser, and a vacuum pump;

[0019] The separation membrane assembly is connected to the demister mechanism and is used to separate isopropanol and water in the gas phase. The first condenser and the second condenser are both connected to the separation membrane assembly. The second condenser is used to condense water. The vacuum pump is connected to the second condenser and is used to guide the water in the separation membrane assembly to the second condenser.

[0020] Furthermore, the separation membrane assembly is a pervaporation membrane separator, and the separation membrane assembly has a gas phase outlet and a permeate outlet, the first condenser is connected to the gas phase outlet, and the second condenser is connected to the permeate outlet.

[0021] Furthermore, the demisting mechanism includes a housing and a demister. The housing is connected to the gas phase outlet of the first evaporator, the separation mechanism is connected to the housing, and the demister is disposed inside the housing.

[0022] Furthermore, the demisting mechanism includes at least two demisters, which are spaced apart within the housing along the gas phase material transport direction.

[0023] Furthermore, the liquid supply assembly includes a delivery pump and a liquid supply pipeline, wherein the delivery pump is connected to the first evaporator through the liquid supply pipeline.

[0024] A cellulose preparation system, including the aforementioned isopropanol recovery device. Attached Figure Description

[0025] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0026] Figure 1 This is a schematic diagram of the structure of an isopropanol recovery device provided in an embodiment of this application.

[0027] Label Explanation:

[0028] 110. Liquid supply assembly; 111. Transfer pump; 112. Liquid supply pipeline; 120. First evaporator; 130. Demisting mechanism; 131. Housing; 132. Demister; 140. Separation mechanism; 141. Separation membrane assembly; 142. Second condenser; 143. Vacuum pump; 150. First condenser; 160. Second evaporator. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] On the one hand, this application provides a device for recovering isopropanol, which can recover isopropanol used in the preparation of cellulose products.

[0032] like Figure 1 As shown, in one embodiment, the recovery device includes a liquid supply assembly 110, a first evaporator 120, a demisting mechanism 130, a separation mechanism 140, and a first condenser 150.

[0033] The liquid supply assembly 110 is used to transport waste liquid. In this embodiment, the waste liquid includes isopropanol solution and solid cellulose product. A first evaporator 120 is connected to the liquid supply assembly 110 to receive the waste liquid transported by the liquid supply assembly 110, and the first evaporator 120 is used to evaporate the waste liquid to form a gaseous substance and residual liquid. The gaseous substance includes gaseous isopropanol and water vapor, and may contain entrained droplets and solids. The entrained droplets include water mist and a small amount of isopropanol, and the entrained solids are small-sized cellulose products. The residual liquid includes isopropanol solution and solid cellulose product.

[0034] The demister 130 is connected to the gas phase outlet of the first evaporator 120. Gaseous material enters the demister 130, which removes impurities. The separation mechanism 140 is connected to the demister 130, allowing the impurity-removed gaseous material to enter and separate gaseous isopropanol and water vapor. The first condenser 150 is connected to the separation mechanism 140 to collect and condense the separated gaseous isopropanol, thereby achieving liquefied collection of isopropanol.

[0035] Furthermore, the recovery device also includes a second evaporator 160, which has a higher evaporation rate than the first evaporator 120. The second evaporator 160 is connected to the liquid phase outlet of the first evaporator 120 to receive the residual liquid produced by the first evaporator 120 and evaporate it to form a solid phase and a gaseous phase. The solid phase is a solid cellulose product, and the gaseous phase includes gaseous isopropanol and water vapor. The gaseous outlet of the second evaporator 160 is connected to a separation mechanism 140 so that the evaporated gaseous material enters the separation mechanism 140. Under the action of the separation mechanism 140, the gaseous isopropanol and water vapor are separated. The separated gaseous isopropanol also enters the first condenser 150 to condense into a liquid and is collected.

[0036] Using the aforementioned isopropanol recovery device, the first evaporator 120 evaporates the waste liquid, forming a gaseous substance and residual liquid. The demister 130 removes impurities entrained in the gaseous substance, and the impurity-free gaseous substance enters the separation mechanism 140. The residual liquid in the first evaporator 120 is fed into the second evaporator 160 for further evaporation. The gaseous substance produced in the second evaporator 160 enters the separation mechanism 140. The separation mechanism 140 separates the gaseous isopropanol from the water vapor, and the gaseous isopropanol is fed into the first condenser 150 to form liquid isopropanol, which is then collected. Because the residual liquid produced by the first evaporator 120 can be further evaporated by the second evaporator 160, which has a higher evaporation rate, the collection of isopropanol in the residual liquid is achieved, effectively reducing the waste of isopropanol discharged with the solid substance and improving the isopropanol recovery rate. Furthermore, the solid substance is a cellulose product, which can be collected after separation from the isopropanol solution, avoiding waste and thus improving the yield of the cellulose product.

[0037] It should be noted that if existing equipment for isopropanol recovery is used, employing a single-stage evaporator to vaporize the isopropanol, it is impossible to recover cellulose products. This application incorporates a second evaporator 160 downstream of the first evaporator 120 for further evaporation, thereby enabling the collection of cellulose products.

[0038] In a preferred embodiment, the first evaporator 120 is a horizontal evaporator, and the second evaporator 160 is a scraped evaporator. It should be noted that the flow rate of waste liquid entering the first evaporator 120 is relatively large, while the amount of residual liquid produced by the first evaporator 120 is much smaller than the amount of waste liquid; therefore, the flow rate of residual liquid entering the second evaporator 160 is relatively small. In a specific embodiment, the waste liquid flow rate is 1800 kg / h, the evaporation temperature in the first evaporator 120 is controlled at 95-100℃, and the pressure is controlled at 0.15-0.20 MPa; the waste liquid flow rate is 50 kg / h, and the evaporation temperature in the second evaporator 160 is controlled at 110-125℃.

[0039] In one embodiment, the liquid supply assembly 110 includes a delivery pump 111 and a liquid supply pipe 112. The delivery pump 111 is connected to the first evaporator 120 through the liquid supply pipe 112, and the delivery pump 111 can be connected to a container containing waste liquid to pump the waste liquid to the first evaporator 120.

[0040] In one embodiment, the demisting mechanism 130 includes a housing 131 and a demister 132. The housing 131 is connected to the gas phase outlet of the first evaporator 120, and the separation mechanism 140 is connected to the housing 131. The demister 132 is disposed inside the housing 131 and is used to remove impurities from the gas phase substances flowing through the housing 131.

[0041] Furthermore, the demisting mechanism 130 includes at least two demisters 132, which are spaced apart within the housing 131 along the direction of gaseous material transport to provide a removal effect for impurities in the gaseous material. It is understood that the demisters 132 can be cleaned or replaced later to avoid clogging.

[0042] Additionally, it should be noted that, as Figure 1 As shown, the housing 131 is directly connected to the top of the first evaporator 120, and the temperature inside the housing 131 is the same as the evaporation temperature inside the first evaporator 120. Therefore, as described above, the liquid impurities in the gaseous substance flowing through the demister 132 are mainly water mist, and very little isopropanol remains on the demister 132, which will not affect the recovery rate of isopropanol.

[0043] In one embodiment, the separation mechanism 140 includes a separation membrane assembly 141, a second condenser 142, and a vacuum pump 143. The separation membrane assembly 141 is connected to a demisting mechanism 130. After gaseous substances enter the separation membrane assembly 141, it separates gaseous isopropanol and water vapor from the gaseous substances. Both the first condenser 150 and the second condenser 142 are connected to the separation membrane assembly 141. The first condenser 150 is used to collect the gaseous isopropanol separated by the separation membrane assembly 141 and condense it into liquid. The second condenser 142 is used to collect the water vapor separated by the separation membrane assembly 141 and condense it into liquid water. The vacuum pump 143 is connected to the second condenser 142 and is used to guide the water vapor in the separation membrane assembly 141 to the second condenser 142.

[0044] In practical applications, the separation membrane assembly 141 is a pervaporation membrane separator. The separation membrane assembly 141 has a gas phase outlet and a permeate outlet. The first condenser 150 is connected to the gas phase outlet, and the second condenser 142 is connected to the permeate outlet. The vacuum pump 143 guides water vapor to permeate through the vaporization membrane and enter the second condenser 142 for condensation.

[0045] In one specific embodiment, the shell temperature of the separation membrane module 141 is controlled at 95-100℃, the pressure is controlled at 0.28-0.32MPa, the vacuum pump 143 is a three-stage Roots vacuum pump 143, and the negative pressure at the permeate outlet of the separation membrane module 141 is -0.098-0.1MPa.

[0046] In one embodiment, the recycling device further includes a preheating mechanism connected to the liquid supply assembly 110 for preheating the waste liquid. For example, the waste liquid is preheated to 50-60°C by the preheating mechanism, thus facilitating the subsequent evaporation treatment of the waste liquid by the first evaporator 120. It should be noted that the preheating mechanism can be located upstream of the liquid supply assembly 110, in which case the waste liquid is preheated first, and then the liquid supply assembly 110 conveys the preheated waste liquid to the first evaporator 120; alternatively, it can be located between the liquid supply assembly 110 and the first evaporator 120, that is, the waste liquid conveyed to the first evaporator 120 is preheated and then directly input into the first evaporator 120.

[0047] It should be explained that, for the first evaporator 120, since the evaporation temperature of the first evaporator 120 is 95-100℃ and the evaporation pressure is 0.15-0.20MPa, the waste liquid, after being preheated, will rapidly boil and vaporize upon entering the first evaporator 120, resulting in severe gas-liquid entrainment. Therefore, a demisting mechanism 130 is required. For the second evaporator 160, the evaporation temperature is controlled at 110-125℃ and the evaporation pressure is 0.15-0.20MPa. Due to the high solid content in the residual liquid and the slower vaporization rate in the second evaporator 160, the gas-liquid entrainment is not significant. Therefore, a demisting mechanism is not required between the second evaporator 160 and the separation mechanism 140.

[0048] Furthermore, the preheating mechanism is a first condenser 150, which is specifically a heat exchanger. The first condenser 150 includes a shell side and a tube side. Its shell side is connected to the separation mechanism 140, and its tube side is connected to the liquid supply assembly 110. The recovered isopropanol separated from the separation mechanism 140 is used to preheat the waste liquid flowing through the first evaporator 120 via the liquid supply assembly 110, and the waste liquid is also used as a refrigerant to cool the isopropanol.

[0049] To facilitate understanding of the technical solution of this application, this document combines... Figure 1 The process flow of the isopropanol recovery device in the above embodiments is described as follows:

[0050] The transfer pump 111 delivers isopropanol waste liquid through the liquid supply pipeline 112. After the preheating mechanism preheats the isopropanol waste liquid, it is delivered to the first evaporator 120. The first evaporator 120 evaporates the waste liquid, and the resulting gaseous substance enters the separation membrane group 141 after passing through the demister 132. The demister 132 removes impurities from the gaseous substance. The residual liquid produced by the first evaporator 120 enters the second evaporator 160, which evaporates the residual liquid. The resulting gaseous substance also enters the separation membrane group 141, while the resulting solid substance can be discharged and collected. The gaseous isopropanol in the separation membrane group 141 enters the first condenser 150 and is condensed into liquid and collected. The water vapor in the separation membrane group 141 is discharged from the permeate port to the second condenser 142 under the action of the vacuum pump 143. The second condenser 142 condenses the water vapor and collects or discharges it.

[0051] On the other hand, this application also provides a cellulose product preparation system, which includes the isopropanol recovery device described in the above embodiments. Therefore, the preparation process of this cellulose product requires the use of isopropanol as a reaction solution and also as a cleaning solution. The aforementioned waste liquids include both the reaction solution and the cleaning solution.

[0052] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for the recovery of isopropyl alcohol, characterized in that, include: Liquid supply assembly for conveying waste liquid; The first evaporator, connected to the liquid supply assembly, is used to evaporate the waste liquid to form gaseous substances and residual liquid. A demisting mechanism is connected to the gas phase outlet of the first evaporator and is used to remove impurities from the gas phase substance; A separation mechanism, connected to the demisting mechanism, is used to separate isopropanol and water from gaseous substances; The first condenser, connected to the separation mechanism, is used to condense isopropanol; The second evaporator is connected to the liquid phase outlet of the first evaporator and is used to evaporate the residual liquid to form solid and gaseous substances. The second evaporator has a higher evaporation rate than the first evaporator, and the gas phase outlet of the second evaporator is connected to the separation mechanism.

2. The recovery apparatus for isopropyl alcohol according to claim 1, characterized by, The first evaporator is a horizontal evaporator, and the second evaporator is a scraped evaporator.

3. The recovery apparatus for isopropyl alcohol according to claim 1, characterized by, It also includes a preheating mechanism, which is connected to the liquid supply assembly and is used to preheat the waste liquid.

4. The isopropanol recovery apparatus according to claim 3, characterized in that, The preheating mechanism is the first condenser, which is a heat exchanger; the heat exchanger includes a shell side and a tube side, the shell side is connected to the separation mechanism, and the tube side is connected to the liquid supply assembly.

5. The isopropanol recovery apparatus according to claim 1, characterized in that, The separation mechanism includes a separation membrane assembly, a second condenser, and a vacuum pump; The separation membrane assembly is connected to the demister mechanism and is used to separate isopropanol and water in the gas phase. The first condenser and the second condenser are both connected to the separation membrane assembly. The second condenser is used to condense water. The vacuum pump is connected to the second condenser and is used to guide the water in the separation membrane assembly to the second condenser.

6. The isopropanol recovery apparatus according to claim 5, characterized in that, The separation membrane assembly is a pervaporation membrane separator, and the separation membrane assembly has a gas phase outlet and a permeate outlet. The first condenser is connected to the gas phase outlet, and the second condenser is connected to the permeate outlet.

7. The isopropanol recovery apparatus according to claim 1, characterized in that, The demisting mechanism includes a housing and a demister. The housing is connected to the gas phase outlet of the first evaporator, the separation mechanism is connected to the housing, and the demister is disposed inside the housing.

8. The isopropanol recovery apparatus according to claim 7, characterized in that, The demisting mechanism includes at least two demisters, which are arranged at intervals within the housing along the gas phase material transport direction.

9. The isopropanol recovery apparatus according to claim 1, characterized in that, The liquid supply assembly includes a delivery pump and a liquid supply pipeline, and the delivery pump is connected to the first evaporator through the liquid supply pipeline.

10. A cellulose preparation system, characterized in that, Includes the isopropanol recovery apparatus according to any one of claims 1-9.

Images