Device for separating liquid containing methanol, water, hydrazine hydrate and toluene
By combining multi-tower continuous distillation with a thin-film evaporator, the problem of efficiently separating mixed waste liquid containing methanol, toluene, and hydrazine hydrate in existing technologies has been solved, achieving low-energy consumption and high-efficiency separation, and obtaining qualified methanol, toluene, and hydrazine hydrate products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technologies are insufficient for efficiently and with low energy consumption to separate mixed waste liquids containing methanol, toluene, and hydrazine hydrate, leading to their classification as hazardous solid waste, which is neither environmentally friendly nor economical.
A multi-tower continuous distillation method is adopted, combining a thin-film evaporator and a water washing tower. Through the combination of a first distillation tower, a water washing tower, a second distillation tower, and a third distillation tower, methanol, water, hydrazine hydrate, and toluene are separated. High-boiling impurities are removed by vacuum evaporation using a thin-film evaporator, and methanol and toluene are extracted in layers using a water washing tower.
It achieves low-energy consumption and high-efficiency recovery of methanol, toluene, and hydrazine hydrate, with good safety, high equipment stability, high separation efficiency, and avoids the generation of high-boiling-point impurities.
Smart Images
Figure CN224056696U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of waste liquid recycling and separation, and in particular to a device for separating liquids containing methanol, water, hydrazine hydrate and toluene. Background Technology
[0002] Hydrazine hydrate, also known as hydrated ammonia, has the molecular formula H6N2O (N2H4·H2O). It is a colorless, transparent, oily liquid with a faint ammonia odor, and is strongly alkaline and hygroscopic. As an important fine chemical raw material, hydrazine hydrate has wide applications in industry, such as in the synthesis of foaming agents like ADC (azodicarbonamide), DIPA (diisopropyl azodicarbonate), and TSH (p-toluenesulfonyl hydrazine); it is also used as a deoxygenating and decarbonizing cleaning agent for boilers and reactors; in the pharmaceutical industry, it is used to produce anti-tuberculosis, anti-diabetic, and antitumor drugs; in the pesticide industry, it is used to produce herbicides, plant growth regulators, and fungicides, insecticides, and rodenticides; in addition, it can be used in the production of rocket fuel, diazo fuel, rubber additives, automotive airbags, and liquid crystal intermediates.
[0003] The synthesis of a certain intermediate generates a mixed waste liquid containing methanol, toluene, and hydrazine hydrate, as well as trace amounts of o-chlorotoluene and other impurities. Without separation, this waste liquid is considered hazardous solid waste, which is neither environmentally friendly nor economical. Simple distillation cannot achieve the desired separation.
[0004] The existing method involves concentrating the mixed wastewater after oxidation treatment by distillation, and then extracting the salts from the concentrated wastewater after evaporation by centrifugation. The recovered salts are then used in the chlor-alkali industry, but this method is energy-intensive.
[0005] Therefore, it is necessary to design a separation device to achieve low-energy consumption and high-efficiency recovery of methanol, toluene, and hydrazine hydrate. Summary of the Invention
[0006] The purpose of this invention is to provide an apparatus for separating liquids containing methanol, water, hydrazine hydrate and toluene.
[0007] To achieve the objective of this utility model, the technical solution is as follows:
[0008] An apparatus for separating a liquid containing methanol, water, hydrazine hydrate, and toluene, the apparatus comprising a first distillation column, a water washing column, a second distillation column, an evaporator, and a third distillation column; wherein the top of the first distillation column is connected to the bottom of the water washing column; the reboiler of the first distillation column is connected to the middle of the second distillation column, the reboiler of the second distillation column is connected to the evaporator, the outlet of the evaporator is connected to the inlet of the third distillation column; and the bottom outlet of the water washing column is connected to the inlet of the first distillation column.
[0009] Furthermore, the tops of the first distillation column, the second distillation column, and the third distillation column are each equipped with a condenser, a reflux tank, and a transfer pump connected in sequence.
[0010] Furthermore, the top of the first distillation column is connected in sequence to the first condenser, the first reflux tank, and the first transfer pump. The output end of the first transfer pump is divided into two pipelines. One pipeline is connected to the top of the first distillation column, and the other pipeline is connected to the bottom of the water washing column through the first distillate storage tank and the first distillate transfer pump, which are set in sequence. The top of the water washing column is also equipped with a water washing column storage tank and a toluene pump to collect the separated toluene.
[0011] Furthermore, the bottom of the water washing tower storage tank is also provided with an outlet; the outlet is connected to the pipeline connecting the bottom discharge port of the water washing tower and the inlet of the first distillation tower.
[0012] Furthermore, the top of the second distillation column is connected in sequence to the second condenser, the second reflux tank, and the second transfer pump. The output end of the second transfer pump is divided into two pipelines, one of which is connected to the top of the second distillation column, and the other is connected to the second column top cooler, the second distillate storage tank, and the second distillate transfer pump, which are arranged in sequence to collect the separated methanol.
[0013] Furthermore, the evaporator is a thin-film evaporator. The reboiler of the second distillation column is connected to the evaporator. The pipeline connecting the outlet of the evaporator to the inlet of the third distillation column also includes a superheater and a second reboiler pump. The reboiler of the second distillation column is connected to the second reboiler pump, the second reboiler pump is connected to the thin-film evaporator, the thin-film evaporator is connected to the superheater, and the outlet of the superheater is connected to the inlet of the third distillation column.
[0014] Furthermore, the top of the third distillation column is connected in sequence to the third condenser, the third reflux tank, and the third transfer pump. The output end of the third transfer pump is divided into two pipelines, one of which is connected to the top of the third distillation column, and the other is connected to the third column top cooler, the third distillate storage tank, and the third distillate transfer pump, which are arranged in sequence, to obtain hydrazine hydrate from the bottom of the third distillation column.
[0015] The significant advantages of this invention compared to existing technologies are:
[0016] 1. By using a thin-film evaporator for reduced pressure evaporation, high-boiling impurities (o-chlorotoluene and other high-boiling-point impurities) in the mother liquor are removed by draining the residual liquid because they are difficult to vaporize. The material refined by evaporation achieves the separation of hydrazine hydrate and high-boiling-point impurities.
[0017] 2. By setting an outlet at the bottom of the water washing tower storage tank and connecting it to the bottom outlet of the water washing tower and the inlet of the first distillation tower, the toluene collected is further stratified through the water washing tower storage tank, and the water and methanol placed at the bottom of the water washing tower storage tank are carried away.
[0018] 3. This application features simple operation, no introduction of a third component, high separation efficiency, good safety, and stable equipment. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the device structure of this utility model.
[0020] Wherein, 1 is the first distillation column, 11 is the first condenser, 12 is the first reflux distributor, 13 is the first distillate storage tank, 14 is the first distillate transfer pump, 2 is the water washing column, 21 is the water washing column storage tank, 22 is the toluene pump, 3 is the second distillation column, 31 is the second condenser, 32 is the second reflux tank, 33 is the second transfer pump, 34 is the second column top cooler, 35 is the second distillate storage tank, 36 is the second distillate transfer pump, 37 is the second column bottom pump, 4 is the thin film evaporator, 41 is the superheater, 5 is the third distillation column, 51 is the third condenser, 52 is the third reflux tank, 53 is the third transfer pump, 54 is the third column top cooler, 55 is the third distillate storage tank, and 56 is the third distillate transfer pump. Detailed Implementation
[0021] The embodiments of this utility model are described in detail below with reference to the accompanying drawings.
[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0023] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0024] In the description of this utility model embodiment, the water washing tower 2 achieves phase separation by washing the mixture with water and allowing it to stand and separate into layers; therefore, it can also be called a "phase separator".
[0025] An apparatus for separating a liquid containing methanol, water, hydrazine hydrate, and toluene includes a first distillation column 1, a water washing column 2, a second distillation column 3, an evaporator, and a third distillation column 5. The top of the first distillation column is connected to the bottom of the water washing column 2; the bottom of the first distillation column is connected to the second distillation column 3; the bottom of the second distillation column 3 is connected to the evaporator; and the outlet of the evaporator is connected to the inlet of the third distillation column 5.
[0026] Furthermore, the bottom outlet of the water washing tower 2 is connected to the inlet of the first distillation tower.
[0027] The above-described apparatus can separate liquids containing methanol, water, hydrazine hydrate, and toluene, as well as o-chlorotoluene and other impurities with boiling points greater than 200°C. In a specific embodiment, the liquid contains 77.5 wt.% methanol, 10 wt.% water, 10 wt.% hydrazine hydrate, 1.25 wt.% toluene, 0.5 wt.% o-chlorotoluene, and 0.75 wt.% other impurities with boiling points greater than 200°C.
[0028] Furthermore, the tops of the first distillation column 1, the second distillation column 3, and the third distillation column 5 are each equipped with a condenser, a reflux tank, and a transfer pump connected in sequence. The top of the first distillation column 1 is connected to the bottom of the water washing column 2. Specifically, the top of the first distillation column 1 is connected in sequence to the first condenser 11, the first reflux tank, and the first transfer pump. The output of the first transfer pump is divided into two pipelines: one pipeline connects to the top of the first distillation column 1, and the other pipeline connects to the first distillate storage tank 13. The first distillate storage tank 13 is connected to the first distillate transfer pump 14, which is connected to the bottom of the water washing column 2. The top of the water washing column 2 is also connected to the water washing column storage tank 21, which is connected to the toluene pump 22 to collect the separated toluene. Preferably, the bottom outlet of the water washing column storage tank 21 is connected to the pipeline connecting the bottom outlet of the water washing column 2 to the inlet of the first distillation column 1. This allows for further stratification of the extracted toluene through the water washing tower storage tank 21, removing the water and methanol located at the bottom of the water washing tower storage tank 21.
[0029] The top of the second distillation column 3 is connected in sequence to the second condenser 31, the second reflux tank 32, and the second transfer pump 33. The output end of the second transfer pump 33 is divided into two pipelines, one connected to the top of the second distillation column 3 and the other connected to the second top cooler 34. The second top cooler 34 is connected to the second distillate storage tank 35. The second distillate storage tank 35 is connected to the second distillate transfer pump 36 to collect the separated methanol.
[0030] The bottom of the second distillation column 3 is connected to the bottom pump 37, which is connected to the thin film evaporator 4. The thin film evaporator 4 is connected to the superheater 41, and the outlet of the superheater 41 is connected to the inlet of the third distillation column 5.
[0031] The top of the third distillation column 5 is sequentially connected to the third condenser 51, the third reflux tank 52, and the third transfer pump 53. The output of the third transfer pump 53 is divided into two pipelines: one connects to the top of the third distillation column 5, and the other connects to the third top cooler 54. The third top cooler 54 is connected to the third distillate storage tank 55, which is connected to the third distillate transfer pump 56. Hydrazine hydrate is obtained from the bottom of the third distillation column 5.
[0032] In the aforementioned apparatus, the reflux tanks and transfer pumps located at the top of the first distillation column 1, the second distillation column 3, and the third distillation column 5 can be replaced with reflux ratio distributors as needed. For example, such as... Figure 1 As shown, a first condenser 11 and a first spool distributor are connected sequentially to the top of the first distillation column 1. After the first spool distributor, the column splits into two pipelines. One pipeline is connected to the top of the first distillation column 1, and the other pipeline is connected to the first distillate storage tank 13. The first distillate storage tank 13 is connected to the bottom of the water washing column 2.
[0033] This apparatus separates methanol, water, hydrazine hydrate, and toluene from the mother liquor through multi-tower continuous distillation. The specific separation process is as follows:
[0034] The mother liquor is first sent to the first distillation column 1 for distillation. The first distillation column 1 operates continuously at atmospheric pressure, with a temperature of 50-72℃, an absolute pressure of 106-108 kPa, and a reflux ratio of 17.5. Feed is taken from the 7th tray. An azeotrope containing water, methanol, and toluene is obtained from the top of the first distillation column 1, and a mixture containing water, hydrazine hydrate, o-chlorotoluene, and heavy impurities is obtained from the bottom of the first distillation column 1, achieving the separation of toluene from other heavy components. The top material from the first distillation column 1 is then pumped to the water washing column 2 for extraction via the first condenser 11, the first reflux ratio distributor 12, the first distillate storage tank 13, and finally the water. The water washing column 2 operates at atmospheric pressure. Crude toluene is fed from the bottom, and water is fed from the top. In the column, the material flows upwards, and the water flows downwards, continuously carrying away methanol from the material. The final product, qualified toluene, is obtained from the top of the column via the water washing column storage tank 21 and the toluene pump 22. The mixture of water and methanol obtained from the bottom of water washing tower 2 is returned to the first distillation tower 1 for processing. The bottom material of the first distillation tower 1 is sent to the second distillation tower 3 for distillation. The second distillation tower 3 operates continuously at atmospheric pressure, with a temperature of 65~107℃, an absolute pressure of 106~128KPA, a reflux ratio of 0.8, and feed from the 14th tray. The product passes through the second condenser 31, the second reflux tank 32, the second transfer pump 33, the second tower top cooler 34, the second distillate storage tank 35, and the second distillate transfer pump 36 to obtain qualified methanol product. A mixture containing water, hydrazine hydrate, o-chlorotoluene, and heavy impurities is obtained from the bottom of the second distillation tower 3, achieving the separation of methanol and other heavy components. The bottom material of the second distillation tower 3 is sent to the thin-film evaporator 4 for vacuum evaporation. High-boiling impurities (o-chlorotoluene and other high-boiling-point impurities) are difficult to vaporize and are discharged through the residual liquid discharge. The material, after evaporation and purification, achieves the separation of hydrazine hydrate and high-boiling-point impurities. After passing through superheater 41, it is sent to the third distillation column 5 for distillation. The third distillation column 5 operates continuously at atmospheric pressure, with a temperature of 103~117℃, an absolute pressure of 130~132KPA, a reflux ratio of 5, and feed from the 6th tray. The material passes from the top of the third distillation column 5 through the third condenser 51, the third reflux tank 52, the third transfer pump 53, the third top cooler 54, the third distillate storage tank 55, and the third distillate transfer pump 56 to obtain water. Hydrazine hydrate is obtained from the bottom of the third distillation column 5.
[0035] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.
Claims
1. An apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene, characterized by: The device comprises a first rectifying tower (1), a water washing tower (2), a second rectifying tower (3), an evaporator and a third rectifying tower (5); wherein the top of the first rectifying tower (1) is connected with the bottom of the water washing tower (2); the tower kettle of the first rectifying tower (1) is connected with the middle of the second rectifying tower (3), the tower kettle of the second rectifying tower (3) is connected with the evaporator, the outlet of the evaporator is connected with the inlet of the third rectifying tower (5); the outlet of the bottom of the water washing tower (2) is connected with the inlet of the first rectifying tower (1).
2. The apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene as claimed in claim 1, wherein: The top of the first rectifying tower (1) is connected with a first condenser (11), a first reflux tank and a first conveying pump in sequence; the output end of the first conveying pump is divided into two pipelines, one of which is connected with the top of the first rectifying tower (1), and the other of which is connected with the bottom of the water washing tower (2) through a first distillate temporary storage tank (13) and a first distillate transfer pump (14) arranged in sequence; the top of the water washing tower (2) is further provided with a water washing tower temporary storage tank (21) and a toluene pump (22) in sequence.
3. The apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene as claimed in claim 2, wherein: The bottom of the water washing tower temporary storage tank (21) is further provided with an outlet; the outlet is connected with the pipeline connecting the outlet of the bottom of the water washing tower (2) with the inlet of the first rectifying tower (1).
4. The apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene as claimed in claim 1, wherein: The top of the second rectifying tower (3) is connected with a second condenser (31), a second reflux tank (32) and a second conveying pump (33) in sequence; the output end of the second conveying pump (33) is divided into two pipelines, one of which is connected with the top of the second rectifying tower (3), and the other of which is connected with the obtained separated methanol through a second tower top cooler (34), a second distillate temporary storage tank (35) and a second distillate transfer pump (36) arranged in sequence.
5. The apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene as claimed in claim 1, wherein: The evaporator is a thin film evaporator (4); the tower kettle of the second rectifying tower (3) is connected with the evaporator, the pipeline connecting the outlet of the evaporator with the inlet of the third rectifying tower (5) further comprises a superheater (41) and a second tower kettle pump (37); the tower kettle of the second rectifying tower (3) is connected with the second tower kettle pump (37), the second tower kettle pump (37) is connected with the thin film evaporator (4), the thin film evaporator (4) is connected with the superheater (41), and the outlet of the superheater (41) is connected with the inlet of the middle of the third rectifying tower (5).
6. The apparatus for separating a liquid containing methanol, water, hydrazine hydrate and toluene as claimed in claim 1, wherein: The top of the third rectifying tower (5) is connected with a third condenser (51), a third reflux tank (52) and a third conveying pump (53) in sequence; the output end of the third conveying pump (53) is divided into two pipelines, one of which is connected with the top of the third rectifying tower (5), and the other of which is connected with the obtained hydrazine hydrate from the tower kettle of the third rectifying tower (5) through a third tower top cooler (54), a third distillate temporary storage tank (55) and a third distillate transfer pump (56) arranged in sequence.