Separation system and method for fusel in Fischer-Tropsch synthesis water

Abstract

The invention provides an efficient and energy-saving system and method for separating fusel from Fischer-Tropsch synthesis water, the system comprises a raw material storage tank, a pressure pump, a preheater, a heater, a membrane separation unit, a vacuum condensation assembly, a back pressure valve and a product cooler, the membrane separation technology and the vacuum condensation technology are combined, efficient separation of the fusel and the water is achieved, and the separation efficiency of the fusel and the water is improved. By means of selective permeability of the membrane separation unit and vacuum pressure provided by the vacuum unit, water permeates from raw materials and is condensed and discharged through the vacuum condensation assembly, uncondensed materials are further treated, the system further has a heat recovery function, heat energy of low-water-content materials is reused for preheating the raw materials, energy consumption is reduced, and compared with a traditional rectification method, the energy consumption is reduced. According to the invention, the separation efficiency is obviously improved, the steam consumption is reduced, the equipment investment and the operation cost are reduced, and the method is suitable for Fischer-Tropsch synthesis water and other related separation processes.

Description

Technical Field

[0001] The present invention relates to the technical field of fusel alcohol separation, and in particular to a system and method for separating fusel alcohols in Fischer-Tropsch synthesis water. Background Art

[0002] With the continuous development and application of Fischer-Tropsch synthesis technology, the separation of water and fusel alcohols has become an important process link. The water and fusel alcohols generated by the Fischer-Tropsch synthesis reaction are usually contained in the synthesis gas product and have different physical and chemical properties. In the process of Fischer-Tropsch synthesis, the separation of water and fusel alcohols is difficult, and the separation efficiency directly affects the subsequent product quality, catalyst stability and reaction economy. Therefore, the development of an efficient and reliable separation method has become a key demand in the industry.

[0003] Existing separation methods mainly include distillation, liquid-liquid extraction, membrane separation, adsorption and other technologies. However, these traditional methods all have certain limitations. As a common separation technology, distillation relies on the relative volatility difference of substances to achieve separation, but water and fusel alcohols are often close in boiling point, resulting in a large amount of energy consumption in the distillation process and low separation efficiency. In addition, the distillation method is complicated to operate and requires a high temperature environment, which not only increases energy consumption, but may also lead to degradation or incomplete separation of certain heat-sensitive substances.

[0004] Although the liquid-liquid extraction method can effectively separate water and fusel alcohols under certain conditions, it often relies on organic solvents, which brings about the problem of solvent recovery and waste disposal. The use of solvents increases the complexity of the separation process and also brings potential environmental pollution risks. The selection and amount of solvents used need to be strictly controlled, and excessive solvents may have a negative impact on the economic efficiency of the separation process.

[0005] Membrane separation technology has been applied to a certain extent in recent years, but it still faces many challenges in the separation of water and fusel alcohols in Fischer-Tropsch synthesis. The choice of membrane material has a decisive influence on the separation performance, but the membrane materials that can withstand high temperatures, are corrosion-resistant and have high selectivity are relatively limited on the market. The efficiency of the membrane separation process is also restricted by factors such as membrane fouling and flux decline, making it difficult to ensure its stability and economy in long-term applications.

[0006] Adsorption is a common separation technology that uses solid adsorbents to adsorb target substances from the liquid phase. However, the selection and regeneration of adsorbents remain difficult issues in the adsorption method. Although some adsorbent materials have high selectivity, adsorbents have poor reusability and may become saturated during the adsorption process, which will affect the stability and continuity of the separation process.

[0007] In addition, the existing technology usually requires complex equipment and process conditions during the treatment process, which not only increases the complexity of the system, but also increases the operating cost. In the process of separating water and fusel alcohol, how to reduce energy consumption, reduce the complexity of equipment, and improve the stability of the process while ensuring efficient separation is still a difficult problem in the development of technology.

[0008] In summary, the existing technologies in the separation process of water and fusel alcohol generally have problems such as high energy consumption, low separation efficiency, complex operation, and difficult equipment maintenance, and various separation methods have certain limitations. Therefore, a new separation technology is urgently needed that can overcome the shortcomings of the existing technology, reduce energy consumption and equipment complexity while ensuring separation efficiency, and improve the sustainability of the separation process. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a separation system for fusel alcohols in Fischer-Tropsch synthesis water, so as to solve the shortcomings of low energy efficiency, poor separation efficiency, complex operation and high energy consumption in the prior art.

[0010] In order to overcome the defects of the above prior art, the present invention provides a separation system for fusel alcohols in Fischer-Tropsch synthesis water, the separation system comprising a raw material storage tank, a pressure pump, a preheater, a heater, a membrane separation unit, a vacuum condensation component, a back pressure valve and a product cooler; The raw material storage tank is used to store the aqueous solution containing fusel alcohol, and the raw material outlet of the raw material storage tank is connected to the pressure pump; The pressure pump is used to transport raw materials, the inlet of which is connected to the raw material outlet of the raw material storage tank, and the outlet is connected to the cold material inlet of the preheater; The preheater is provided with a first material inlet, a first material outlet, a second material inlet, and a second material outlet, and the first material outlet is connected to the inlet of the heater; The heater is used to heat the raw material delivered by the first material outlet of the preheater, and the outlet of the heater is connected to the inlet of the membrane separation unit; The outlet of the membrane separation unit is connected to the inlet of the vacuum condensation component, and the membrane separation unit is provided with a low-water-content material outlet and a high-water-content material outlet, and the high-water-content material outlet is connected to the inlet of the vacuum condensation component, and the low-water-content material outlet is connected to the second material inlet of the preheater; The vacuum condensation component is used to condense materials with high water content, and its outlet is connected to the outside; The inlet of the back pressure valve is connected to the second material outlet, and the outlet of the back pressure valve is connected to the inlet of the product cooler; The product cooler is used for cooling the obtained low water-containing organic solvent.

[0011] Compared with the prior art, the present invention provides a system for separating fusel alcohols from Fischer-Tropsch synthesis water, which has the following advantages: the separation efficiency is significantly improved: the prior art usually adopts the traditional distillation method or other complex chemical separation methods, which have limited separation effect and high energy consumption. The present invention adopts the membrane separation unit and vacuum condensation technology, which can efficiently separate fusel alcohols from water, and the process is simplified, reducing the intermediate links and operation steps; Significant energy-saving effect: Traditional distillation requires a large amount of low-pressure steam for heating and fractionation, which consumes a lot of energy. The present invention reduces energy consumption to a minimum through membrane separation technology, and achieves effective utilization of heat by recycling heat, reducing steam consumption and achieving significant energy-saving effect;

[0012] Easy operation and strong adaptability: Compared with the traditional distillation tower system, the integrated design of the membrane separation unit and the vacuum condensation component of the present invention makes the operation easier, not only shortening the separation cycle, but also having strong adaptability, and being able to flexibly adjust the operating conditions according to the changes in the properties of the raw materials; Reduced equipment investment and operating costs: Since the membrane separation unit and vacuum condensation system are more efficient and energy-saving than traditional distillation devices, the system of the present invention can reduce steam consumption while reducing dependence on high-temperature and high-pressure equipment, thereby reducing equipment investment and operating costs; In the present invention, water molecules selectively diffuse through the membrane layer under the impetus of the pressure difference of components on both sides of the membrane, thereby realizing continuous and efficient separation of fusel alcohol and water under steady-state conditions. The vacuum condensation technology ensures the pressure difference of components on both sides of the membrane through the low-pressure environment provided by the vacuum unit.

[0013] In a possible embodiment, the vacuum condensation component is composed of a vacuum condenser and a vacuum unit, and the vacuum condenser is provided with an inlet, a gas outlet and a liquid outlet, the inlet of the vacuum condenser is connected to the permeate outlet of the membrane separation unit, and the gas outlet of the vacuum condenser is connected to the inlet of the vacuum unit.

[0014] Compared with the prior art, the above technical solution can more effectively remove moisture from the high-water-content material in the membrane separation unit under low-pressure conditions through the coordinated use of a vacuum condenser and a vacuum unit. The vacuum unit provides a low-pressure environment to reduce the boiling point of the material, so that the moisture can be effectively evaporated at a lower temperature and discharged through the gas outlet, thereby avoiding energy consumption and operational complexity under high-temperature and high-pressure environments. Compared with the traditional distillation tower system and method, the separation system and method of the present invention requires less energy consumption (including low-pressure steam, circulating water and other public works) for dehydration using molecular sieve membranes while achieving the same effect. This is because the traditional distillation tower in the prior art needs to heat all the substances multiple times, while the liquid phase molecular sieve membrane in the above separation system of the present invention only needs to heat the extracted permeate portion, and at the same time, it can avoid the formation of azeotropes between fusel alcohols and water, and the temperature is too high. The method of the present invention can achieve efficient separation of fusel alcohol and water at lower energy consumption by using membrane separation technology and vacuum condensation technology, and can significantly reduce the consumption of low-pressure steam by combining the heat exchange of the preheater and the setting and control of the various components and methods in the present invention. Compared with the traditional distillation method, the system of the present invention can save up to 64% of low-pressure steam; compared with the traditional separation method (such as distillation), the use of the vacuum condensation component in the present invention can significantly reduce energy consumption; the traditional distillation method requires a large amount of heat energy to evaporate and separate water, and by adopting vacuum condensation technology, not only can low pressure be used to reduce heat consumption, but also condensed water under low temperature conditions can be effectively collected, reducing the consumption of external energy, and by adjusting the pressure in the system by the vacuum unit, the condensation effect can be flexibly adjusted under different working conditions. Controlling the change of pressure allows the system to adapt to different material characteristics and production requirements, thereby improving the applicability of the system and the possibility of industrial application. The vacuum condensation component of the present invention makes the separation process more concise and efficient. Traditional methods may require multiple heat exchange and condensation steps, while vacuum condensers directly condense high-water-content materials at low temperatures, greatly simplifying the steps and equipment requirements in the separation process, and improving the convenience of operation and the reliability of the system.

[0015] In a possible implementation, the liquid outlet of the vacuum condenser is connected to a sewage treatment system, and the outlet of the vacuum unit is connected to a pipeline of an exhaust gas treatment system.

[0016] Compared with the prior art, the above-mentioned technical scheme is adopted to effectively recycle and treat wastewater and tail gas, which not only improves the recycling rate of resources in the production process and reduces environmental pollution, but also can further optimize the operating cost and efficiency of the system. Compared with traditional technology, this design makes the present invention more sustainable and economical in industrial applications.

[0017] In a possible implementation, the membrane separation unit includes at least one membrane assembly, a liquid phase molecular sieve membrane is disposed in the membrane assembly, and a vacuum pipeline is disposed on the membrane assembly.

[0018] Compared with the existing technology, the above-mentioned technical solution, by introducing a vacuum pipeline into the membrane separation unit, can significantly improve the separation efficiency without increasing the operating pressure, while reducing energy consumption and optimizing the working state and stability of the membrane component. Compared with the existing technology, this solution not only improves the separation accuracy and efficiency, but also reduces the energy consumption and maintenance requirements of the equipment, ensuring that the system maintains good performance during long-term operation, and enhancing the separation performance through at least one membrane component.

[0019] In a possible implementation, the membrane separation unit is a liquid phase molecular sieve membrane.

[0020] Compared with the prior art, the above technical solution is adopted, through the liquid phase molecular sieve membrane, the physical separation mechanism is adopted, and the energy consumption can be significantly reduced compared with the traditional thermodynamic method (such as distillation). The liquid phase molecular sieve membrane only needs to heat part of the permeate, without heating the entire material flow, thereby reducing the waste of heat energy. Especially in the case of combining with vacuum condensation technology, low temperature conditions can be effectively used for evaporation and condensation of water, further reducing the energy consumption of the system, and the liquid phase molecular sieve membrane can also effectively separate substances according to molecular size and shape. Compared with traditional membrane materials, the molecular sieve membrane can accurately screen fusel alcohol and water molecules, providing higher separation efficiency and more accurate separation results. By using a liquid phase molecular sieve membrane, fusel alcohol can be more effectively separated from Fischer-Tropsch synthesis water, avoiding the problem of insufficient selectivity in traditional membrane separation methods. By using a molecular sieve membrane, the present invention can provide higher selectivity, separation accuracy and processing efficiency in the separation process, and further synergistically reduce the energy consumption of the system, while improving the stability and durability of the system. Compared with existing technologies, molecular sieve membranes can improve separation effects while reducing energy consumption, providing a more efficient, energy-saving and durable technical solution for the separation of fusel alcohols in Fischer-Tropsch synthesis water.

[0021] Another technical problem to be solved by the present invention is to provide a method for separating fusel alcohols in Fischer-Tropsch synthesis water to solve the shortcomings of low energy efficiency, poor separation efficiency, complex operation and high energy consumption in the prior art.

[0022] In order to overcome the above defects of the prior art, the present invention provides a method for separating fusel alcohols in Fischer-Tropsch synthesis water, wherein the separation method is implemented by the above separation system, comprising the following steps: S1: The aqueous solution containing fusel alcohol is transported to a pressure pump through a raw material storage tank, energy is applied to the raw material by the pressure pump, and the raw material is transported to a preheater; S2: transporting the pressurized raw materials to a preheater and heating the raw materials; S3: The preheated raw material is transported to the heater, where the raw material is further heated to the operating temperature; S4: The raw material treated by the heater is transported to the membrane separation unit, and the membrane separation unit separates the material by the selective permeability of the membrane, and the water content of the permeate is removed; S5: On the water permeation side of the membrane separation unit, the vacuum pressure provided by the vacuum unit is used to promote the permeation of water from the raw material; S6: The high-water-content material on the permeate side is sent to the vacuum condenser. At this stage, the material is condensed into liquid, and the condensed permeate is discharged outside the boundary. The uncondensed material is sent to the vacuum unit; S7: returning the low-water-content organic solvent that has passed through the membrane separation unit to the preheater for heat recovery, and the low-water-content organic solvent flows into the preheater to further exchange heat with the raw material that has just passed into the preheater; S8: Use a back pressure valve to adjust the material pressure on the raw material side of the membrane separation unit to ensure the operation of the membrane separation unit and further guide the low-water organic solvent to the product cooler; S9: The low water content organic solvent is cooled by a product condenser and then stored or used later.

[0023] Compared with the prior art, the present invention has the following advantages: High-efficiency energy consumption control: Compared with the traditional distillation method, the present invention significantly reduces energy consumption by combining membrane separation technology with a vacuum condensation system. During the separation process, the traditional method often requires a large amount of heat energy for distillation, while the present invention utilizes the selective permeability of the membrane and the low-pressure environment provided by the vacuum unit to efficiently remove moisture and reduce the demand for external energy. Specifically, the following advantages are also included: Simplified operation steps: Compared with the existing complex chemical reactions or multi-stage distillation steps, the membrane separation technology used in the present invention reduces the use of chemical substances in the separation process through the physical separation principle, simplifies the operation process, and can achieve efficient separation in a shorter time; Improve separation accuracy: By precisely controlling the pressure and temperature in the membrane separation unit, the present invention can more accurately control the separation effect of water and fusel alcohol, ensuring higher separation accuracy. Compared with traditional thermodynamic methods, membrane separation technology can achieve higher selective separation, especially when dealing with complex substances, it can significantly improve separation efficiency;

[0024] Compact equipment, saving space: By integrating multiple functional units such as membrane separation unit, vacuum condensation assembly and back pressure valve, the present invention can integrate multiple steps into a compact device, reducing the equipment footprint, and reducing equipment investment and maintenance costs for industrial production; Improve resource recovery rate: The method of the present invention can effectively recover the heat energy of low-water-content materials and use it for raw material heating by setting up an efficient heat recovery mechanism. This energy efficiency utilization greatly improves the overall energy utilization rate of the system and further reduces operating costs.

[0025] Through the above-mentioned technical means, the present invention can provide an efficient and energy-saving method for separating fusel alcohols in Fischer-Tropsch synthesis water, which not only solves the problems of high energy consumption and low separation efficiency in the prior art, but also ensures the simplification of equipment and maximum utilization of energy in industrial applications.

[0026] In a possible implementation, in step S2, the preheater is heated by recovering heat from the high-temperature, low-water-content material produced by the membrane separation unit for heating.

[0027] In a possible implementation, in step S3, the temperature of the preheated raw material is 70-80°C, and the condition for further heating to the operating temperature is to heat the raw material to 105-115°C by low-pressure steam.

[0028] Compared with the prior art, the present invention adopts the above technical solution, and by combining low-pressure steam and heat recovery of high-temperature and low-water-content materials produced by the membrane separation unit, it can simultaneously utilize energy sources during the raw material preheating process, thereby maximizing the energy utilization efficiency. The low-pressure steam in the heater provides a stable heat source, and the high-temperature and low-water-content materials produced by the membrane separation unit recover their heat and absorb it in the preheater, further reducing the dependence on external energy and reducing the overall energy consumption of the system. The above implementation method maximizes energy utilization, reduces operating costs, improves the overall efficiency of the system, and enhances the stability and life of the equipment by combining low-pressure steam heating and heat recovery of high-temperature and low-water-content materials produced by the membrane separation unit in the preheater. This solution has obvious advantages in energy conservation, emission reduction and cost control, and provides efficient technical support for industrial applications.

[0029] In a possible implementation, in step S5, the vacuum pressure is above 8000 Pa.A.

[0030] Compared with the prior art, the above technical solution can create a greater driving force on the water permeation side of the membrane separation unit by setting the vacuum pressure to above 8000Pa.A. This higher vacuum pressure helps to accelerate the removal of water from the raw material through the selective permeability of the membrane, significantly increasing the water permeation rate during the membrane separation process, thereby speeding up the overall separation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the separation system of fusel alcohols in Fischer-Tropsch synthesis water in the present invention; In the figure, 1. raw material storage tank; 2. pressure pump; 3. preheater; 4. heater; 5. membrane separation unit; 6. vacuum condensation component; 61. vacuum condenser; 62. vacuum unit; 7. back pressure valve; 8. product condenser. DETAILED DESCRIPTION

[0032] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0033] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0034] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The present invention provides a separation system for fusel alcohols in Fischer-Tropsch synthesis water, the separation system comprising a raw material storage tank 1, a pressure pump 2, a preheater 3, a heater 4, a membrane separation unit 5, a vacuum condensation component 6, a back pressure valve 7 and a product cooler; The raw material storage tank 1 is used to store an aqueous solution containing fusel alcohol, and the raw material outlet of the raw material storage tank 1 is connected to the pressure pump 2; The pressure pump 2 is used to transport raw materials, and its inlet is connected to the raw material outlet of the raw material storage tank 1, and its outlet is connected to the cold material inlet of the preheater 3; The preheater 3 is provided with a first material inlet, a first material outlet, a second material inlet, and a second material outlet, and the first material outlet is connected to the inlet of the heater 4; The heater 4 is used to heat the raw material delivered by the first material outlet of the preheater 3, and the outlet of the heater 4 is connected to the inlet of the membrane separation unit 5; The outlet of the membrane separation unit 5 is connected to the inlet of the vacuum condensation component 6, and the membrane separation unit 5 is provided with a low-water-content material outlet and a high-water-content material outlet, and the high-water-content material outlet is connected to the inlet of the vacuum condensation component 6, and the low-water-content material outlet is connected to the second material inlet of the preheater 3; The vacuum condensation component 6 is used to condense high-water-content materials, and its outlet is connected to the outside; The inlet of the back pressure valve 7 is connected to the second material outlet, and the outlet of the back pressure valve 7 is connected to the inlet of the product cooler; The product cooler is used for cooling the obtained low water-containing organic solvent.

[0036] As a preferred solution, the vacuum condensation component 6 consists of a vacuum condenser 61 and a vacuum unit 62, and the vacuum condenser 61 is provided with an inlet, a gas outlet and a liquid outlet, the inlet of the vacuum condenser 61 is connected to the high-water-content material outlet of the membrane separation unit 5, and the gas outlet of the vacuum condenser 61 is connected to the inlet of the vacuum unit 62.

[0037] As a preferred solution, the liquid outlet of the vacuum condenser 61 is connected to a sewage treatment system, and the outlet of the vacuum unit 62 is connected to a pipeline of an exhaust gas treatment system.

[0038] As a preferred solution, the membrane separation unit 5 includes at least one membrane assembly, and a vacuum pipeline is provided on the membrane assembly. If the number of membrane assemblies is two or more, the membrane separation unit 5 is formed by connecting them in series.

[0039] As a preferred solution, the membrane separation unit 5 is a liquid phase molecular sieve membrane.

[0040] In the structural description of the above dehydration system, the parts that can be determined by the technicians in this field through the existing technology in the field are not described. These parts can be exemplified by but not limited to: pipes for connecting various devices, materials for storing and / or supplying organic solvent aqueous solutions, product storage tanks for receiving / processing fusel alcohol products, etc. In addition, combined with the above description, the technicians in this field can determine the most appropriate equipment selection and model selection according to the design needs and requirements under the guidance of the existing technology, and it is unnecessary to elaborate.

[0041] The present invention also provides a method for separating fusel alcohols in Fischer-Tropsch synthesis water, which is implemented by the above separation system and comprises the following steps: S1: The aqueous solution containing fusel alcohol is transported to the pressure pump 2 through the raw material storage tank 1, the pressure pump 2 is used to apply energy to the raw material, and the raw material is transported to the preheater 3; S2: conveying the pressurized raw material to the preheater 3 and heating the raw material; S3: The preheated raw material is transported to the heater 4, where the raw material is further heated to the operating temperature; S4: The raw material treated by the heater 4 is transported to the membrane separation unit 5, and the membrane separation unit 5 separates the material by the selective permeability of the membrane, and the water content of the permeate is removed; S5: On the water permeation side of the membrane separation unit 5, the vacuum pressure provided by the vacuum unit 62 is used to promote the permeation of water from the raw material; S6: The high water content material on the permeate side is sent to the vacuum condenser 61, during which the material is condensed into liquid, the condensed water is discharged, and the uncondensed material is sent to the vacuum unit 62; S7: returning the low-water-content organic solvent that has passed through the membrane separation unit 5 to the preheater 3 for heat recovery, and the low-water-content organic solvent flows into the preheater 3 to further exchange heat with the raw material that has just passed into the preheater 3; S8: Use the back pressure valve 7 to adjust the material pressure on the feedstock side of the membrane separation unit 5 to ensure the operation of the membrane separation unit 5 and further guide the low-water organic solvent to the product cooler; S9: The low-water-content organic solvent is cooled by the product condenser 8 and then stored or used later.

[0042] As a preferred solution, in step S2, the preheater 3 is heated by recovering heat from the high-temperature and low-water-content material produced by the membrane separation unit 5 for heating.

[0043] As a preferred solution, in step S3, the temperature of the preheated raw material is 70-80°C, and the condition for further heating to the operating temperature is to heat the raw material to 105-115°C by low-pressure steam.

[0044] As a preferred solution, in step S5, the vacuum pressure is above 1000 Pa.A.

[0045] The following provides specific embodiments in combination with the above-mentioned technical solutions to further illustrate the technical solutions of the present invention: Embodiment 1: This embodiment provides a system and method for separating fusel alcohols in Fischer-Tropsch synthesis water, the separation system comprising: A raw material storage tank 1, a pressure pump 2, a preheater 3, a heater 4, a membrane separation unit 5, a vacuum condensation component 6, a back pressure valve 7 and a product cooler; the vacuum condensation component 6 is composed of a vacuum condenser 61 and a vacuum unit 62, and the vacuum condenser 61 is provided with an inlet, a gas outlet and a liquid outlet, the inlet of the vacuum condenser 61 is connected to the high water content material outlet of the membrane separation unit 5, and the gas outlet of the vacuum condenser 61 is connected to the inlet of the vacuum unit 62; The raw material storage tank 1 is used to connect the raw material with the pipeline outside the boundary area, and is provided with a raw material outlet connected to the pressure pump 2; The booster pump 2 is used to impart energy to the raw material and transport the material, and its inlet and outlet are respectively connected to the raw material storage tank 1 and the inlet of the preheater 3; The raw material of the preheater 3 is cold material, and the hot material is the high-temperature and low-water material of the membrane separation unit 5. Part of the heat can be recovered in the preheater 3, and the heat of the raw material and the high-temperature and low-water material is exchanged, thereby reducing steam energy consumption and saving costs; The raw material of the heater 4 after the preheater 3 is cold material, and the heating method is low-pressure steam heating, which is used to further heat the raw material to the operating temperature; The membrane separation unit 5 is composed of one or more membrane modules in series, the material inlet of the first membrane module is connected to the outlet of the heater 4, the material outlet of the last membrane module is connected to the inlet of the vacuum condenser 61, and a vacuum pipeline is provided on one side of each module; The vacuum condenser 61 is used to condense the material coming out of the permeate side of the membrane separation unit 5. The permeate material is hot material, and the cold material is cooling circulating water. The hot material inlet of the vacuum condenser 61 is connected to the vacuum outlet collection pipe of the membrane separation unit 5. The condensed material of the vacuum condenser 61 is connected to the high-water condensate pipeline on the permeate side and then discharged to the sewage treatment system. The vacuum unit 62 is used to provide vacuum to the water permeation side of the membrane separation unit 5 and extract uncondensed materials, and is provided with a material inlet connected to the outlet of the vacuum condenser 61, and a material outlet for connecting to the tail gas treatment system pipeline; The backup pressure valve is used to assist in imparting pressure to the material on the raw material side of the membrane separation unit 5, and is provided with an inlet connected to the material outlet of the membrane separation unit 5 through the preheater 3, and is provided with an outlet connected to the inlet of the product condenser 8; The hot material in the product condenser 8 is a low-water content product that has been cooled by waste heat recovery, and the cold material is circulating water used for product cooling; In this embodiment, Fischer-Tropsch synthesis water containing 30.00 wt% of water is used, the feed rate is 1000 kg / h, and the water content of the product is less than 15 wt%; The following are the separation methods using this system: S1: The Fischer-Tropsch synthesis water raw material containing 30.00 wt% of water is transported from the raw material storage tank 1 to the pressure pump 2, and energy is given to the material through the pressure pump 2.

[0046] S2: After passing through the pressure pump 2, the raw material enters the preheater 3. In the preheater 3, the raw material and the high-temperature material are heat-recovered, and the temperature rises to 75°C.

[0047] S3: The preheated raw material enters the heater 4 through the first material outlet of the preheater 3. Through the heater 4, the raw material is further heated to an operating temperature of 110° C. under the heating effect of low-pressure steam, and enters the membrane separation unit 5 in a liquid state.

[0048] S4: After the material enters the raw material side of the membrane separation unit 5, it begins to be dehydrated by the selective permeability of the membrane and is dehydrated to below 15.0 wt%.

[0049] S5: On the water permeation side of the membrane separation unit 5, the vacuum pressure (8000 Pa.A) provided by the vacuum unit 62 promotes the permeation of water from the raw material.

[0050] S6: The material on the permeate side enters the vacuum condenser 61 for condensation, and the condensed material is discharged to the sewage treatment system through the high water content condensate pipeline, and the uncondensed material enters the inlet of the vacuum unit 62. The cold material is the cooling circulating water.

[0051] S7: The high-temperature, low-water content product extracted from the membrane separation unit 5 enters the preheater 3 for heat recovery. The hot stream is the extracted high-temperature product, and the cold stream is the raw material that has obtained heat.

[0052] S8: Use the back pressure valve 7 to adjust the material pressure on the feedstock side of the membrane separation unit 5 , the inlet of the back pressure valve 7 is connected to the hot material outlet of the preheater 3 , and the outlet is connected to the hot material inlet of the product condenser 8 .

[0053] S9: The low-water-content organic solvent cooled by the product condenser 8 enters the storage tank or is used in other processes, and the cold material is circulating water.

[0054] In the above embodiment, the water content of Fischer-Tropsch water is reduced from 30% to below 15%, and a total of 817 kg / h of low-water Fischer-Tropsch water is obtained. The low-pressure steam consumption is 0.34 t / t product, which can save 64% of low-pressure steam per ton of product compared with the conventional distillation process in Comparative Example 1 (low-pressure steam consumption is 0.95 t / t product). If the daily output of Fischer-Tropsch water is 76 tons, 48.64 tons of low-pressure steam can be saved every day, and the low-pressure steam consumption can be reduced by about 17,510 tons per year.

[0055] Embodiment 2: This embodiment provides a system and method for separating fusel alcohols in Fischer-Tropsch synthesis water. The separation system is the same as that in Embodiment 1. The separation method comprises the following steps: S1: The Fischer-Tropsch synthesis water raw material (feed rate of 1000 kg / h) containing 28.00 wt% of water is transported from the raw material storage tank 1 to the booster pump 2, and the booster pump 2 imparts energy to the material.

[0056] S2: After passing through the pressure pump 2, the raw material enters the preheater 3. In the preheater 3, the raw material and the high-temperature material are heat-recovered, and the temperature rises to 70°C.

[0057] S3: The preheated raw material enters the heater 4 through the first material outlet of the preheater 3. Through the heater 4, the raw material is further heated to an operating temperature of 105° C. under the heating effect of low-pressure steam, and enters the membrane separation unit 5 in a liquid state.

[0058] S4: After the material enters the raw material side of the membrane separation unit 5, it begins to be dehydrated by the selective permeability of the membrane and is dehydrated to below 12.0 wt%.

[0059] S5: On the water permeation side of the membrane separation unit 5, the vacuum pressure (8500 Pa.A) provided by the vacuum unit 62 promotes the permeation of water from the raw material.

[0060] S6: The material on the permeate side enters the vacuum condenser 61 for condensation, and the condensed material is discharged to the sewage treatment system through the high water content condensate pipeline, and the uncondensed material enters the inlet of the vacuum unit 62. The cold material is the cooling circulating water.

[0061] S7: The high-temperature, low-water content product extracted from the membrane separation unit 5 enters the preheater 3 for heat recovery. The hot stream is the extracted high-temperature product, and the cold stream is the raw material that has obtained heat.

[0062] S8: Use the back pressure valve 7 to adjust the material pressure on the feedstock side of the membrane separation unit 5 , the inlet of the back pressure valve 7 is connected to the hot material outlet of the preheater 3 , and the outlet is connected to the hot material inlet of the product condenser 8 .

[0063] S9: The low-water-content organic solvent cooled by the product condenser 8 enters the storage tank or is used in other processes, and the cold material is circulating water.

[0064] In the above embodiment, the water content of Fischer-Tropsch water is reduced from 28% to below 12%, and a total of 880 kg / h of low-water Fischer-Tropsch water is obtained. The low-pressure steam consumption is 0.38 t / t product, which can save 60% of low-pressure steam per ton of product compared with the conventional distillation process in Comparative Example 1 (low-pressure steam consumption is 0.95 t / t product). If the daily output of Fischer-Tropsch water is 76 tons, 45.6 tons of low-pressure steam can be saved every day, and the low-pressure steam consumption can be reduced by about 16,656 tons per year.

[0065] Embodiment 3: This embodiment provides a system and method for separating fusel alcohols in Fischer-Tropsch synthesis water. The separation system is the same as that in Embodiment 1. The separation method comprises the following steps: S1: The Fischer-Tropsch synthesis water raw material (feed rate of 1000 kg / h) containing 32.00 wt% of water is transported from the raw material storage tank 1 to the booster pump 2, and energy is imparted to the material through the booster pump 2.

[0066] S2: After passing through the pressure pump 2, the raw material enters the preheater 3. In the preheater 3, the raw material and the high-temperature material are heat-recovered, and the temperature rises to 80°C.

[0067] S3: The preheated raw material enters the heater 4 through the first material outlet of the preheater 3. Through the heater 4, the raw material is further heated to an operating temperature of 115° C. under the heating effect of low-pressure steam, and enters the membrane separation unit 5 in a liquid state.

[0068] S4: After the material enters the raw material side of the membrane separation unit 5, it begins to be dehydrated by the selective permeability of the membrane and is dehydrated to below 16.0 wt%.

[0069] S5: On the water permeation side of the membrane separation unit 5, the vacuum pressure (8000 Pa.A) provided by the vacuum unit 62 promotes the permeation of water from the raw material.

[0070] S6: The material on the permeate side enters the vacuum condenser 61 for condensation, and the condensed material is discharged to the sewage treatment system through the high water content condensate pipeline, and the uncondensed material enters the inlet of the vacuum unit 62. The cold material is the cooling circulating water.

[0071] S7: The high-temperature, low-water content product extracted from the membrane separation unit 5 enters the preheater 3 for heat recovery. The hot stream is the extracted high-temperature product, and the cold stream is the raw material that has obtained heat.

[0072] S8: Use the back pressure valve 7 to adjust the material pressure on the feedstock side of the membrane separation unit 5 , the inlet of the back pressure valve 7 is connected to the hot material outlet of the preheater 3 , and the outlet is connected to the hot material inlet of the product condenser 8 .

[0073] S9: The low-water-content organic solvent cooled by the product condenser 8 enters the storage tank or is used in other processes, and the cold material is circulating water.

[0074] In the above embodiment, the water content of Fischer-Tropsch water is reduced from 32% to below 16%, and a total of 850 kg / h of low-water Fischer-Tropsch water is obtained. The low-pressure steam consumption is 0.36 t / t product, which can save 62% of low-pressure steam per ton of product compared with the conventional distillation process in Comparative Example 1 (low-pressure steam consumption is 0.95 t / t product). If the daily output of Fischer-Tropsch water is 76 tons, 46.72 tons of low-pressure steam can be saved every day, and the low-pressure steam consumption can be reduced by about 17,048 tons per year.

[0075] Comparative Example: This comparative example provides a method for separating fusel alcohols in Fischer-Tropsch synthesis water, which uses a traditional distillation tower for separation. The method comprises the following steps: S1: The Fischer-Tropsch synthesis water raw material containing 30.00 wt% of water (feed rate of 1000 kg / h) is transported from the raw material storage tank 1 to the preheater 3.

[0076] S2: After the raw material passes through the preheater 3, the raw material is heated to an operating temperature of 75°C using low-pressure steam in the heater 4 and is transported to the distillation tower unit in a liquid phase.

[0077] S3: A Fischer-Tropsch synthesis water stream with a water content of less than 15 wt% is obtained at the top of the distillation tower, and an acid water stream is obtained at the bottom of the tower. The distillation tower has 20-50 theoretical plates, a reflux ratio of 1-10, a top temperature of 70-100°C, and a bottom temperature of 80-160°C.

[0078] S4: The Fischer-Tropsch synthesis water flow produced from the top of the tower is cooled by the top condenser and then enters the subsequent process section, and the cold material is circulating water; the acid water flow at the bottom of the tower enters the subsequent process section for further treatment after passing through the bottom condenser, and the cold material is circulating water.

[0079] In the above comparative example, the water content of Fischer-Tropsch synthesis water was reduced from 30% to below 15%, and a total of 780 kg / h of low-water Fischer-Tropsch synthesis water was obtained, and the low-pressure steam (0.4-0.5 MPa G) consumption was 0.95 t / t product.

[0080] In summary, the comparison between the above embodiments and the comparative examples further proves the advantages of the embodiments of the present invention over the comparative examples, especially in terms of energy efficiency, energy saving and cost. Compared with the traditional method of the comparative example, the separation system and method of the present invention, while achieving the same effect, requires less energy consumption (specifically, public works such as low-pressure steam and circulating water) for dehydration using molecular sieve membranes. The reason is that the traditional distillation tower needs to heat all substances multiple times, while the liquid phase molecular sieve membrane in the present invention only needs to heat the extracted permeate. At the same time, it can avoid the formation of azeotropes between fusel alcohols and water, and the polymerization or decomposition of certain substances due to excessively high temperatures. The method of the present invention can achieve Efficient separation of fusel alcohol and water is achieved at lower energy consumption, and combined with the heat exchange of the preheater 3, as well as the setting and method control of each component in the present invention, the consumption of low-pressure steam is significantly reduced. Compared with the traditional distillation method, the present invention saves up to 64% of low-pressure steam. In addition, the combination of the membrane separation unit 5 improves the separation efficiency, so that the moisture content in the Fischer-Tropsch synthesis water is reduced from 30% to below 15%, and the operation process is simple and energy-efficient, reducing complex chemical treatment and energy waste. In summary, the present invention further reduces energy consumption through the design of multiple components, such as the preheater 3, which recovers energy to preliminarily heat the material, and then further heats it through the heater 4, as well as the above-mentioned liquid phase molecular sieve membrane.

[0081] In the process of the present invention, the raw material is Fischer-Tropsch synthesis water containing fusel alcohol, and the water content can be adjusted as needed. The raw material is heated and treated by devices such as a pressure pump 2, a preheater 3, and a heater 4, and then enters a membrane separation unit 5 for separation, and finally undergoes a vacuum condensation treatment to remove moisture. The core of this process is the efficient combination of membrane separation technology and a vacuum condensation system, which can quickly and effectively separate fusel alcohol and water, and recover heat to reduce waste of resources.

[0082] The present invention provides a high-efficiency, low-energy separation method and system, which is not only suitable for the separation of fusel alcohols from Fischer-Tropsch synthesis water, but also has broad industrial application prospects. It can be applied to the separation of solvents and water in multiple chemical processes, providing an optimized technical path for related industries.

[0083] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0084] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0085] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A system for separating fusel alcohols in Fischer-Tropsch synthesis water, characterized in that: The separation system comprises a raw material storage tank (1), a pressure pump (2), a preheater (3), a heater (4), a membrane separation unit (5), a vacuum condensation component (6), a back pressure valve (7) and a product cooler; The raw material storage tank (1) is used to store an aqueous solution containing fusel alcohol, and the raw material outlet of the raw material storage tank (1) is connected to the inlet of the pressure pump (2); The pressure pump (2) is used to transport raw materials, and its inlet is connected to the raw material outlet of the raw material storage tank (1), and its outlet is connected to the cold material inlet of the preheater (3); The preheater (3) is provided with a first material inlet, a first material outlet, a second material inlet, and a second material outlet, and the first material outlet is connected to the inlet of the heater (4); The heater (4) is used to heat the raw material delivered by the first material outlet of the preheater (3), and the outlet of the heater (4) is connected to the inlet of the membrane separation unit (5); The outlet of the membrane separation unit (5) is connected to the inlet of the vacuum condensation component (6), and the membrane separation unit (5) is provided with a low-water-content material outlet and a high-water-content material outlet, and the high-water-content material outlet is connected to the inlet of the vacuum condensation component (6), and the low-water-content material outlet is connected to the second material inlet of the preheater (3); The vacuum condensation component (6) is used to condense materials with a high water content, and its outlet is connected to the outside; The inlet of the back pressure valve (7) is connected to the second material outlet, and the outlet of the back pressure valve (7) is connected to the inlet of the product cooler; The product cooler is used for cooling the obtained low water-containing organic solvent.

2. The separation system of fusel alcohols in Fischer-Tropsch synthesis water according to claim 1, characterized in that: The vacuum condensation component (6) is composed of a vacuum condenser (61) and a vacuum unit (62), and the vacuum condenser (61) is provided with an inlet, a gas outlet and a liquid outlet, the inlet of the vacuum condenser (61) is connected to the high-water-content material outlet of the membrane separation unit (5), and the gas outlet of the vacuum condenser (61) is connected to the inlet of the vacuum unit (62).

3. The separation system of fusel alcohols in Fischer-Tropsch synthesis water according to claim 2, characterized in that: The liquid outlet of the vacuum condenser (61) is connected to a sewage treatment system, and the outlet of the vacuum unit (62) is connected to a pipeline of an exhaust gas treatment system.

4. The system for separating fusel alcohols in Fischer-Tropsch synthesis water according to claim 1, characterized in that: The membrane separation unit (5) comprises at least one membrane assembly, and a vacuum pipeline is provided on the membrane assembly.

5. The system for separating fusel alcohols in Fischer-Tropsch synthesis water according to claim 1, characterized in that: The membrane separation unit (5) is a liquid phase molecular sieve membrane.

6. A method for separating fusel alcohols in Fischer-Tropsch synthesis water, characterized in that: The separation method is implemented by the separation system according to any one of claims 1 to 5, comprising the following steps: S1: The aqueous solution containing fusel alcohol is transported to the pressure pump (2) through the raw material storage tank (1), energy is applied to the raw material by the pressure pump (2), and the raw material is transported to the preheater (3); S2: conveying the pressurized raw material to the preheater (3) and heating the raw material; S3: conveying the preheated raw material to the heater (4), where the raw material is further heated to the operating temperature; S4: transporting the raw material treated by the heater (4) to the membrane separation unit (5), where the membrane separation unit (5) separates the material and removes water from the permeate; S5: On the water permeation side of the membrane separation unit (5), using the vacuum pressure provided by the vacuum unit (62) to promote the permeation of water from the raw material; S6: The high-water-content material on the permeate side is sent to a vacuum condenser (61), where the material is condensed into liquid, the condensed permeate is discharged, and the uncondensed material is sent to a vacuum unit (62); S7: returning the low-water-content organic solvent that has passed through the membrane separation unit (5) to the preheater (3) for heat recovery; the low-water-content organic solvent flows into the preheater (3) and undergoes further heat exchange with the raw material that has just passed into the preheater (3); S8: using a back pressure valve (7) to adjust the material pressure on the raw material side of the membrane separation unit (5) to ensure the operation of the membrane separation unit (5) and further guide the low water content organic solvent to the product cooler; S9: The low water content organic solvent is cooled by the product condenser (8) and then stored or used later.

7. The method for separating fusel alcohols in Fischer-Tropsch synthesis water according to claim 6, characterized in that: In the step S2, the preheater (3) is heated by recovering heat from the high-temperature, low-water-content material produced by the membrane separation unit (5) for heating.

8. The method for separating fusel alcohols in Fischer-Tropsch synthesis water according to claim 6, characterized in that: In the step S3, the temperature of the preheated raw material is 70-80°C, and the condition for further heating to the operating temperature is to heat the raw material to 105-115°C by low-pressure steam.

9. The method for separating fusel alcohols in Fischer-Tropsch synthesis water according to claim 6, characterized in that: In the step S5, the vacuum pressure is above 1000 Pa.A.

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