Device and method for separating water and trihydroxy propionaldehyde through heat pump rectification

Abstract

The invention discloses a device and method for separating water and trihydroxy propionaldehyde through heat pump rectification. The device comprises a water recovery tower, a heat exchanger, a trihydroxy formaldehyde water separation tank, a compressor, a tower bottom condenser, a tower top condenser, a water separation tank, a reflux pump and a trihydroxy propionaldehyde recovery tower. By utilizing the characteristic that the temperature of the tower top and the tower kettle of a rectifying tower for separating crude trihydroxy propionaldehyde does not exceed 20 DEG C, a heat pump rectification technology is used, low-grade heat of distillates at the tower top of a water recovery tower is changed into a high-grade heat source through a compressor, heat in the system is fully used through heat integration in the system, and consumption of external public works is reduced. A small amount of power consumption is used, a large amount of steam consumption is saved, and the effect of saving the operation cost of the device is achieved.

Description

Technical Field

[0001] The present application relates to the field of preparing trihydroxypropionaldehyde by acrolein hydration and chemical energy-saving technology, and specifically to a device and method for separating water and trihydroxypropionaldehyde by heat pump distillation. Background Art

[0002] Trihydroxypropionaldehyde is an important organic chemical raw material with a wide range of uses. It is the main raw material for the preparation of biological sterilants, anti-infective therapeutic agents, biological cross-linking agents, and new biomaterials. 3-Hydroxypropionaldehyde (3-HPA) is not only an effective antibacterial agent that can be used for food preservation and auxiliary treatment, but also a synthetic precursor for many organic compounds such as acrolein, acrylic acid and 1,3-propylene glycol. It has broad application prospects and market prospects in the chemical industry.

[0003] The industrial production method of trihydroxypropionaldehyde mainly produces 3-HPA through ethylene oxide carbonylation, acrolein hydration and bioconversion from glycerol.

[0004] The process conditions for preparing trihydroxypropionaldehyde by acrolein hydration are mature and the yield is high. Due to the decreasing non-renewable resources such as petroleum and the increasing world population and environmental pressure, the application value of 3-HPA in the chemical industry has attracted people's attention. The acrolein hydration reaction is the addition of acrolein to water under the action of a catalyst to obtain 3-HPA. The use of multi-phase catalytic reaction for acrolein hydration can obtain a higher conversion rate and selectivity and is easy to separate. The conversion rate and selectivity of the hydration reaction are both above 85%.

[0005] The document ELSC.201300122 proposes an extractive distillation process for separating trihydroxypropionaldehyde from a raw material mixture, and proposes several types of extractants and distillation methods, but the extractive separation effects are not significant and the extractant consumption is high.

[0006] Patent CN1116041162A proposes a method for separating and recovering acrolein from a product system of 3-hydroxypropionaldehyde. The method utilizes vacuum distillation and thin film evaporation to separate acrolein, wherein the residence time of the product system in the distillation tower can be reduced by the advantage of thin film evaporation, thereby greatly reducing the content of cyclic dimers or linear polymer by-products, thereby reducing the difficulty of subsequent separation, so that acrolein and 3-hydroxypropionaldehyde can be separated from the product system of 3-hydroxypropionaldehyde prepared by hydration of acrolein with high stability, and impurities such as acetaldehyde, propionaldehyde, and acetone in acrolein are removed by a multi-tower distillation scheme, but the method has high operating costs and increases the complexity of control.

[0007] Patent CN109704950A proposes a relatively simple process for treating a crude aqueous solution containing 3-hydroxypropionic acid by combining extraction and recrystallization to greatly improve the purity of the recovered 3-hydroxypropionic acid. However, this method has a small processing capacity and cannot be used for continuous production.

[0008] In summary, the prior art has many problems in the crude trihydroxypropionaldehyde separation process: (1) poor separation effect: even if a variety of extractants are tried in the extraction distillation method, the separation effect is not ideal and the extraction cost is high; (2) high operating cost: although the vacuum distillation and thin film evaporation methods can reduce the generation of by-products, the equipment investment and operating costs are high and the control is complex; (3) small processing volume and cannot be continuously produced: although the recrystallization method can improve the purity, the processing volume is small and is not suitable for large-scale industrial production. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a device and method for separating water and trihydroxypropionaldehyde by heat pump distillation, so as to solve the problems of poor separation effect, high energy consumption, small processing capacity, high operating cost and difficulty in by-product treatment in the prior art.

[0010] In order to solve the above technical problems, this application adopts the following technical solutions:

[0011] A device for separating water and trihydroxypropionaldehyde by heat pump distillation, comprising a water recovery tower, a heat exchanger, a trihydroxyformaldehyde water separation tank, a compressor, a bottom condenser, a top condenser, a water separation tank, a reflux pump and a trihydroxypropionaldehyde recovery tower;

[0012] Among them, the bottom of the water recovery tower is connected to the heat exchanger fluid through a pressure reducing valve; the heat exchanger is connected to the trihydroxypropionaldehyde water separation tank fluid, the top of the trihydroxypropionaldehyde water separation tank obtains water vapor phase I, and the bottom obtains trihydroxypropionaldehyde and by-products; the top of the trihydroxyformaldehyde water separation tank is connected to the bottom condenser fluid through a compressor, and the bottom condenser is connected to the bottom fluid of the water recovery tower; the bottom of the trihydroxyformaldehyde water separation tank is connected to the bottom fluid of the trihydroxypropionaldehyde recovery tower through a reflux pump, and the top of the trihydroxypropionaldehyde recovery tower is connected to the bottom fluid of the water recovery tower.

[0013] Preferably, a reboiler is also included, and the bottom distillate of the trihydroxypropionaldehyde recovery tower returns to the bottom of the trihydroxypropionaldehyde recovery tower after passing through the reboiler, and the reboiler provides heat for the kettle of the trihydroxypropionaldehyde recovery tower.

[0014] Preferably, a plurality of tower plates are provided inside the water recovery tower, and the number of the tower plates is 15 to 30.

[0015] Preferably, the number of plates in the trihydroxypropionaldehyde recovery tower is 2 to 10.

[0016] The present application also provides a method for separating water and trihydroxypropionaldehyde by heat pump distillation, wherein the method uses the above-mentioned device to separate water and trihydroxypropionaldehyde, and the method specifically includes the following circuits:

[0017] Loop 1: Crude trihydroxypropionaldehyde enters from the top of the water recovery tower, and the bottom material enters the heat exchanger for heat exchange after being decompressed by the pressure reducing valve, and then enters the trihydroxypropionaldehyde water separation tank to obtain a water vapor phase I and a mixture of trihydroxypropionaldehyde and by-products;

[0018] Loop 2: The water vapor phase I obtained in loop 1 is compressed by a compressor and then enters the bottom condenser for cooling, and then returns to the water recovery tower after cooling;

[0019] Loop 3: The mixture of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower through a reflux pump; at the same time, the trihydroxypropionaldehyde recovery tower supplies heat to its bottom through a reboiler;

[0020] Loop 4: The distillate I from the top of the water recovery tower enters the heat exchanger for heat exchange and provides heat for the bottom of the water recovery tower. After heat exchange, the distillate I from the top of the tower enters the top condenser for cooling, and then enters the water separation tank for separation. The bottom of the water separation tank produces recovered water, and the water vapor phase II produced from the top of the water separation tank enters the water recovery tower from the top of the tower.

[0021] Loop 5: The top distillate II produced from the top of the trihydroxypropionaldehyde recovery tower enters the water recovery tower from the bottom of the tower, and the bottom product enters the subsequent separation device.

[0022] Preferably, the operating temperature of the water recovery tower is 100° C. to 135° C., and the operating pressure is -0.05 MPa to 1 MPa.

[0023] Preferably, the operating pressure of the water recovery tower is -0.05MPa to 0.3MPa, the top temperature is 80°C to 90°C, and the bottom temperature is 90°C to 120°C; in loop 2, the position where the water vapor phase I enters the water recovery tower is the position of the first tower plate in the tower.

[0024] Preferably, the operating pressure of the trihydroxypropionaldehyde recovery tower is -0.05MPa~0.3MPa, the top temperature is 100℃~120℃, and the bottom temperature is 140℃~180℃; in loop 3, the position where the mixture of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower is the position of the first tower plate in the tower.

[0025] Preferably, the outlet pressure of the compressor is 0.1 MPa to 0.2 MPa, and the outlet temperature is 110° C. to 130° C.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] 1. This application designs a device for separating water and trihydroxypropionaldehyde using heat pump distillation technology. By taking advantage of the fact that the temperature of the top and bottom of the distillation tower for separating crude trihydroxypropionaldehyde does not exceed 20°C, the heat pump distillation technology is used to convert the low-grade heat of the distillate from the top of the water recovery tower into a high-grade heat source through a compressor, and through heat integration within the system, the heat inside the system is fully utilized to reduce the consumption of external utilities. That is, a small amount of electricity consumption is used, a large amount of steam consumption is saved, and the effect of saving the operating cost of the device is achieved.

[0028] 2. The device described in the present application passes the distillate from the top of the water recovery tower through a heat exchanger, and then transfers the heat of the high-temperature logistics (top distillate) to the low-temperature logistics (bottom logistics of the water recovery tower) through countercurrent heat exchange, thereby reducing the external heating demand and improving energy efficiency; at the same time, the heat of the water vapor phase I is effectively recovered through the condenser to reduce energy consumption; and the water vapor phase and trihydroxypropionaldehyde and by-products are effectively separated through the trihydroxypropionaldehyde water separation tank, thereby improving the purity of the product and further reducing the difficulty of subsequent processing; further, a closed-loop system is formed between the water recovery tower and the trihydroxypropionaldehyde recovery tower, thereby realizing multiple recycling of materials, reducing material waste, and improving the overall material utilization rate.

[0029] 3. The method described in the present application has good operational flexibility and stability. The bottom pressure of the tower is controlled by a pressure reducing valve to keep the pressure in the tower within a set range, thereby preventing operational problems caused by overpressure or underpressure and ensuring the operational stability and safety of the water recovery tower. The reflux amount of trihydroxypropionaldehyde and by-products is controlled by a reflux pump, so the operating conditions in the tower can be flexibly adjusted to improve the separation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flowchart of the method described in the present application.

[0031] In the figure: water recovery tower 1, pressure reducing valve 2, heat exchanger 3, trihydroxypropionaldehyde water separation tank 4, compressor 5, bottom condenser 6, top condenser 7, water separation tank 8, reflux pump 9, trihydroxypropionaldehyde recovery tower 10, crude trihydroxypropionaldehyde A, top distillate IB, recovered water C, water vapor phase ID, mixture of trihydroxypropionaldehyde and by-products E, top distillate II F, bottom output G. DETAILED DESCRIPTION

[0032] This application will combine the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on this application belong to the scope of protection of this application.

[0033] Unless otherwise indicated in specific cases in this application, the numerical ranges listed herein include the upper and lower limits, as well as all integers and fractions within the range, and are not limited to the specific values ​​listed when defining the range.

[0034] 1. A device for separating water and trihydroxypropionaldehyde by heat pump distillation

[0035] The device described in the present application includes a water recovery tower 1, a heat exchanger 3, a trihydroxyformaldehyde water separation tank 4, a compressor 5, a bottom condenser 6, a top condenser 7, a water separation tank 8, a reflux pump 9 and a trihydroxypropionaldehyde recovery tower 10.

[0036] Among them, the bottom of the water recovery tower 1 is fluidly connected to the heat exchanger 3 through a pressure reducing valve 2; the heat exchanger 3 is fluidly connected to the trihydroxypropionaldehyde water-dividing tank 4, the top of the trihydroxypropionaldehyde water-dividing tank 4 obtains water vapor phase I, and the bottom thereof obtains trihydroxypropionaldehyde and by-products; the top of the trihydroxyformaldehyde water-dividing tank 4 is fluidly connected to the bottom condenser 6 through a compressor 5, and the bottom condenser 6 is fluidly connected to the bottom of the water recovery tower 1; the bottom of the trihydroxyformaldehyde water-dividing tank 4 is fluidly connected to the bottom of the trihydroxypropionaldehyde recovery tower 10 through a reflux pump 9, and the top of the trihydroxypropionaldehyde recovery tower 10 is fluidly connected to the bottom of the water recovery tower 1.

[0037] Considering the many problems existing in the prior art, the present application conceives to improve the separation device. The primary purpose of the conception is to achieve energy recovery and utilization, reduce the demand for external heating, and thus achieve the purpose of reducing energy consumption; secondly, to improve the recycling rate of materials, and then achieve a higher separation and purification effect through reduced steps; furthermore, the present application also needs to consider reducing the generation of by-products, improving product purity, and the entire process can be continuously produced, providing a basis for industrial application. On the basis of this concept, the present application adopts a combination of a heat exchanger and a bottom condenser, and the bottom of the water recovery tower 1 is connected to the heat exchanger 3 fluid through a pressure reducing valve 2. This design makes full use of the waste heat of the bottom flow, and transfers the heat to the top distillate I through the heat exchanger 3, realizing efficient recovery and utilization of energy, reducing the demand for external heating, and thus achieving the purpose of reducing energy consumption. Then, the trihydroxypropionaldehyde water-dividing tank is used to effectively separate the water vapor phase I from the trihydroxypropionaldehyde and the by-products, and the water vapor phase I obtained at the top of the water-dividing tank 4 is sent to the bottom condenser 6 by the compressor 5, and the condensed water returns to the bottom of the water recovery tower 1, and this design ensures the efficient recovery and reuse of water, and reduces the waste of water resources; At the same time, the bottom of the water-dividing tank 4 sends the trihydroxypropionaldehyde and the by-products to the trihydroxypropionaldehyde recovery tower 10 by the reflux pump 9, realizes the recycling of materials, and improves the overall material utilization rate. Then, the present application adopts the synergistic effect of the compressor and the bottom condenser, and the compressor 5 compresses the water vapor phase I at the top of the water-dividing tank 4, improves its pressure and temperature, and then sends it to the bottom condenser 6, and the bottom condenser 6 condenses the compressed water vapor phase I into liquid water, and then sends it back to the bottom of the water recovery tower 1, and in this process, not only water is recovered, but also the heat released in the compression process is utilized, and the energy utilization efficiency is further improved. Subsequently, trihydroxypropionaldehyde recovery tower 10 is used to further separate and purify trihydroxypropionaldehyde and by-products, and the overhead distillate II is returned to the bottom of the water recovery tower 1, which not only realizes the recycling of materials, improves the purity of trihydroxypropionaldehyde, reduces the generation of by-products, but also reduces the difficulty of processing the bottom output. Finally, the present application can achieve continuous production through reasonable logistics design and equipment configuration, and the material recycling between the water recovery tower 1 and the trihydroxypropionaldehyde recovery tower 10, as well as the synergistic effect of the compressor 5 and the bottom condenser 6, ensure the stable operation of the system. In addition, through the automatic control system, the operating parameters of each device can be monitored and adjusted in real time to ensure the efficiency and stability of the separation process.

[0038] In some embodiments of the present application, a reboiler 11 is further included. The bottom distillate of the trihydroxypropionaldehyde recovery tower 10 returns to the bottom of the trihydroxypropionaldehyde recovery tower 10 after passing through the reboiler 11. The reboiler 11 provides heat energy for the trihydroxypropionaldehyde recovery tower 10 to evaporate the bottom flow and maintain the distillation process in the tower.

[0039] In some embodiments of the present application, the water recovery tower is provided with a plurality of plates, and the number of the plates is 15 to 30. When the number of plates is less than 15, the contact area between the gas and liquid phases will be insufficient, the mass transfer efficiency will be low, the separation effect will be poor, and the incomplete separation will require more processing steps to improve the purity, which will undoubtedly increase the overall energy consumption; when the number of plates is higher than 30, the pressure drop in the tower will increase, and a higher operating pressure and a larger pumping power will be required, which will undoubtedly increase the energy consumption; at the same time, the operating conditions will become more complicated, and the excessive number of plates will cause the material to stay in the tower for too long, increase the generation of by-products (such as cyclic dimers and linear polymers), and affect the quality and yield of the final product; it will also lead to extended start-up and shutdown time, affecting production efficiency and equipment utilization. Therefore, the number of plates can be 15, 18, 20, 24, 27, 29, 30, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0040] In some embodiments of the present application, the number of plates in the trihydroxypropionaldehyde recovery tower is 2 to 10. Below this number, the mass transfer efficiency of the trihydroxypropionaldehyde recovery tower will be low, the separation will not be thorough, and the operation will be unstable, which will further increase energy consumption and reduce equipment utilization; while above this number, by-products will be more likely to be produced, especially cyclic dimers and linear polymers, which will be more likely to generate by-products than water recovery towers, thereby affecting the final yield quality and yield. Therefore, the number of plates in the trihydroxypropionaldehyde recovery tower can be 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0041] 2. A method for separating water and trihydroxypropionaldehyde by heat pump distillation

[0042] The method described in the present application adopts the above-mentioned device, and the method specifically includes the following circuit:

[0043] Loop 1: Crude trihydroxypropionaldehyde enters from the top of the water recovery tower, and the bottom material enters the heat exchanger 3 for heat exchange after being decompressed by the pressure reducing valve 2, and enters the trihydroxypropionaldehyde water separation tank 4 after heat exchange to obtain a water vapor phase I and a mixture of trihydroxypropionaldehyde and by-products. The bottom material enters the heat exchanger 3 after being decompressed by the pressure reducing valve 2, and transfers the heat to the top distillate I, realizing internal energy recovery, reducing the need for external heating, and reducing energy consumption; at the same time, the water vapor phase I and the mixture of trihydroxypropionaldehyde and by-products are effectively separated by the trihydroxypropionaldehyde water separation tank 4, thereby improving the purity and recovery rate of the material; the pressure reducing valve 2 ensures the stability of the bottom pressure, avoids operational problems caused by pressure fluctuations, and improves operational stability.

[0044] Loop 2: The water vapor phase I obtained in loop 1 is compressed by compressor 5 and then enters the bottom condenser 6 for cooling, and then returns to the water recovery tower 1 after cooling. In this loop, the water vapor phase I is compressed by compressor 5 to increase its pressure and temperature, and then condensed into liquid water in the bottom condenser 6 and returned to the water recovery tower 1, thereby realizing efficient recovery and reuse of water; at the same time, the heat released during the compression process is recovered by the bottom condenser 6, further improving the energy utilization efficiency.

[0045] Loop 3: The mixture of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9; at the same time, the trihydroxypropionaldehyde recovery tower 10 supplies heat to its bottom through the reboiler. In this loop, the mixture of trihydroxypropionaldehyde and by-products is sent to the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, which realizes the recycling of materials and improves the material utilization rate; and the trihydroxypropionaldehyde recovery tower 10 supplies heat to its bottom through the reboiler, ensuring the operating conditions in the tower and improving the purity and yield of trihydroxypropionaldehyde; the use of the reboiler allows the bottom temperature of the tower to be flexibly adjusted to adapt to different operating conditions and improve the operational flexibility.

[0046] Loop 4: The top distillate I of the water recovery tower 1 enters the heat exchanger 3 for heat exchange and provides heat for the bottom of the water recovery tower 1. After heat exchange, the top distillate I enters the top condenser 7 for cooling, and then enters the water separation tank 8 for separation; the bottom of the water separation tank 8 produces recovered water, and the top produces water vapor phase II which enters the water recovery tower 1 from the top of the tower. The top distillate I transfers heat to the bottom flow through the heat exchanger 3, realizing internal energy recovery, reducing the need for external heating, and reducing energy consumption; the water vapor phase II and the recovered water are effectively separated through the top condenser 7 and the water separation tank 8, improving the purity and recovery rate of the material; the water vapor phase II re-enters the water recovery tower 1 from the top of the tower, realizing the recycling of water and reducing resource waste.

[0047] Loop 5: The overhead distillate II produced at the top of the trihydroxypropionaldehyde recovery tower 10 enters the water recovery tower 1 from the bottom of the tower, and the bottom product enters the subsequent separation device. In this loop, the overhead distillate II produced at the top of the trihydroxypropionaldehyde recovery tower 10 enters the water recovery tower 1 from the bottom of the tower, further improving the purity and yield of trihydroxypropionaldehyde; through reasonable logistics design, the continuous flow of materials is achieved, and the production efficiency and equipment utilization are improved.

[0048] The method described in the present application utilizes the coordination of various circuits to achieve internal energy recovery through heat exchangers and condensers, thereby reducing the need for external heating and lowering energy consumption; water and trihydroxypropionaldehyde are effectively separated through a water separation tank and a condenser, thereby improving the purity and recovery rate of the material; the pressure reducing valve and reboiler ensure the stability of the operating conditions and improve the operational stability; and the circulation design of the reflux pump and the tower achieves the recycling of materials and improves the utilization rate of materials. The design of each circuit has its unique advantages. Through reasonable logistics design, the continuous flow of materials is achieved, and the production efficiency and equipment utilization rate are improved, which together constitute an efficient, energy-saving and environmentally friendly trihydroxypropionaldehyde separation and recovery system.

[0049] In some embodiments of the present application, the operating temperature of the water recovery tower is preferably in the range of 100°C to 135°C, and the operating pressure is in the range of -0.05MPa to 1MPa, and is further preferably in the range of -0.05MPa to 0.3MPa. If the operating temperature and operating pressure exceed the range described in the present application, the energy-saving effect of the heat pump will be reduced and the operating cost will increase. Therefore, the operating temperature of the water recovery tower can be 100°C, 110°C, 120°C, 130°C, 135°C, etc., as well as all ranges and sub-ranges between the above values; the operating pressure of the water recovery tower can be -0.05MPa, 0, 0.12MPa, 0.14MPa, 0.15MPa, 0.2MPa, 0.24MPa, 0.25MPa, 0.26MPa, 0.3MPa , 0.5MPa, 1MPa, etc., and all ranges and sub-ranges between the above values; the water recovery tower top temperature preferably ranges from 80°C to 90°C, which can be 80°C, 85°C, 90°C, etc., and all ranges and sub-ranges between the above values; the tower bottom temperature preferably ranges from 90°C to 120°C, which can be 90°C, 100°C, 110°C, 120°C, etc., and all ranges and sub-ranges between the above values; it should be understood that in the embodiment, any of the above ranges can be combined with any other ranges. In loop 2, the position where the water vapor phase I enters the water recovery tower is the position of the first tray in the tower. The water recovery tower top compressor 5 is used to increase the temperature of the water recovery tower top distillate I, so that the water recovery tower 1 bottom can be heated by the heat exchanger 3, thereby realizing the internal recovery of energy, reducing the demand for external heating, and reducing energy consumption. Among them, the operating temperature refers to the average temperature range inside the entire tower, which determines the overall thermal state of the material in the tower and ensures its effective gas-liquid separation. The tower top temperature is the temperature of the tower top distillate I, and the tower bottom temperature is the temperature of the tower bottom stream.

[0050] In some embodiments of the present application, the temperature and pressure of the trihydroxypropionaldehyde recovery tower exceed the range described in the present application, which will lead to reduced energy-saving effect of the heat pump and increased operating costs. The operating pressure of the trihydroxypropionaldehyde recovery tower 10 is preferably in the range of -0.05MPa to 0.3MPa, which can be -0.05MPa, 0, 0.12MPa, 0.14MPa, 0.15MPa, 0.2MPa, 0.24MPa, 0.25MPa, 0.26MPa, 0.3MPa, etc., as well as the above All ranges and sub-ranges between the values; the preferred range of the top temperature of the trihydroxypropionaldehyde recovery tower is 100°C to 120°C, which can be 100°C, 110°C, 120°C, etc., and all ranges and sub-ranges between the above values; the preferred range of the bottom temperature is 140°C to 180°C, which can be 140°C, 150°C, 160°C, 170°C, 180°C, etc., and all ranges and sub-ranges between the above values; it should be understood that in the embodiment, any of the above ranges can be combined with any other ranges. In loop 3, the position where the mixture of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower is the position of the first tower plate in the tower. The trihydroxypropionaldehyde and its by-products flowing out of the trihydroxypropionaldehyde water separation tank 8 are separated by the trihydroxypropionaldehyde recovery tower 10 to obtain dehydrated trihydroxypropionaldehyde and by-products.

[0051] In some embodiments of the present application, the outlet pressure of the compressor will affect the compression efficiency and energy consumption of the compressor, thereby reducing the stability of the entire process, thereby further affecting subsequent operations. The outlet pressure of the compressor is preferably in the range of 0.1MPa to 0.2MPa, which can be 0.1MPa, 0.12MPa, 0.14MPa, 0.15MPa, 0.17MPa, 0.2MPa, etc., and all ranges and sub-ranges between the above values; the outlet temperature is preferably in the range of 110°C to 130°C, which can be 110°C, 115°C, 120°C, 125°C, 130°C, etc., and all ranges and sub-ranges between the above values; it should be understood that, in the implementation scheme, any of the above ranges can be combined with any other ranges.

[0052] 3. Examples and Comparative Examples

[0053] The crude trihydroxypropionaldehyde obtained by the trihydroxypropionaldehyde production unit of acrolein hydration method in a certain factory was simulated by Aspen V14 Plus process as an example. The composition of the crude trihydroxypropionaldehyde is shown in Table 1:

[0054] Table 1

[0055] name Crude trihydroxypropionaldehyde Temperature, °C 105 Pressure, MPa 0.15 Mass flow, kg / hr 42391 Composition, water mass fraction % 90.17 Composition, trihydroxypropionaldehyde mass fraction % 8.15

[0056] Example 1

[0057] The crude trihydroxypropionaldehyde A from the upstream device enters the water recovery tower 1, and the operating pressure of the water recovery tower 1 is 0.14MPa and the operating temperature is 105°C.

[0058] Crude trihydroxypropionaldehyde A enters the first plate of water recovery tower 1. The theoretical number of plates of water recovery tower 1 is 16, and the operating pressure is 0.14MPa. Part of crude trihydroxypropionaldehyde is extracted from the bottom of water recovery tower 1, with a flow rate of 53470kg / hr. It is first reduced to 0.12MPa by pressure reducing valve 2, and then passes through heat exchanger 3 to exchange heat of 14362.7KW before entering trihydroxypropionaldehyde water separation tank 4. The water vapor phase ID extracted from the top of trihydroxypropionaldehyde water separation tank 4 enters compressor 5 and is compressed to 0.14MPa. Finally, it exchanges heat of 767.9KW through bottom condenser 6, and returns to the 17th plate of water recovery tower after cooling to 105°C, with a flow rate of 23836.9kg / h.

[0059] The distillate IB from the top of the water recovery tower has a flow rate of 45829 kg / hr and enters the heat exchanger 3 to provide heat for the crude trihydroxypropionaldehyde, exchanging 14362.7 kW of heat. After the heat exchange, it enters the top condenser 7 in turn with a heat load of -14398.5 kW, and is cooled to 105°C. Part of the water vapor phase II is extracted through the water separator 8 with a flow rate of 38233 kg / h. The remaining water vapor phase II is circulated back to the first plate of the water recovery tower 1 with a flow rate of 7596 kg / h.

[0060] The mixture E of trihydroxypropionaldehyde and by-products extracted from the bottom of the trihydroxypropionaldehyde water separation tank 4 enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, and enters the first plate of the trihydroxypropionaldehyde tower 10, with a flow rate of 29632.8 kg / h. The distillate II F at the top of the trihydroxypropionaldehyde reflux tower 10 enters the 17th plate of the water recovery tower 1 for heating, with a flow rate of 25475 kg / h and a temperature of 109°C. The heat load of the reboiler 11 is 14697.9 kW. The mixture E of trihydroxypropionaldehyde and by-products is extracted from the bottom of the trihydroxypropionaldehyde recovery tower 10, with a flow rate of 4158 kg / h and a temperature of 169°C.

[0061] Table 2 Composition of recycled water obtained in Example 1

[0062] name Recycled water Temperature, °C 99.65 Pressure, MPa 0.14 Mass flow, kg / hr 38232.02 Composition, mass fraction% Water, 99.97

[0063] Compared with Comparative Example 1, the present application uses a heat pump distillation process to convert the heat of low-grade overhead distillate I into high-grade heat, and through heat integration within the system, fully utilizes the energy within the system, only increases power consumption by 350kW, and reduces steam load by 28726kW, significantly reducing the operating cost of the device.

[0064] Example 2

[0065] The crude trihydroxypropionaldehyde A from the upstream device enters the water recovery tower 1, and the operating pressure of the water recovery tower is 0.25MPa and the operating temperature is 126°C.

[0066] Crude trihydroxypropionaldehyde A enters the first plate of water recovery tower 1. The theoretical number of plates of water recovery tower 1 is 14, and the operating pressure is 0.25MPa. Part of crude trihydroxypropionaldehyde is extracted from the bottom of water recovery tower 1, with a flow rate of 64591kg / hr. It is first reduced to 0.2MPag by pressure reducing valve 2, and then passes through heat exchanger 3 to exchange heat of 16775.1KW before entering trihydroxypropionaldehyde water separation tank 4. The water vapor phase ID extracted from the top of trihydroxypropionaldehyde water separation tank 4 enters compressor 5 and is compressed to 0.25MPa. Finally, it exchanges heat of 1737KW through bottom condenser 6, and returns to the first plate of water recovery tower 1 after cooling to 129°C, with a flow rate of 10448kg / h.

[0067] The distillate IB from the top of the water recovery tower has a flow rate of 53260 kg / hr and enters the heat exchanger 3 to provide heat for the crude trihydroxypropionaldehyde, exchanging 16775.1 kW of heat. After the heat exchange, it enters the top condenser 7 in turn with a heat load of -15508 kW and is cooled to 127°C. Part of the water vapor phase II is extracted through the water separator 8 with a flow rate of 42812 kg / h. The remaining water vapor phase II is circulated back to the first plate of the water recovery tower 1 with a flow rate of 10449 kg / h.

[0068] The mixture E of trihydroxypropionaldehyde and by-products extracted from the bottom of the trihydroxypropionaldehyde water separation tank 4 enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, and enters the first plate of the trihydroxypropionaldehyde tower 10, with a flow rate of 35770kg / h. The distillate II F at the top of the trihydroxypropionaldehyde reflux tower 10 enters the 15th plate of the water recovery tower 1 for heating, with a flow rate of 28211kg / h and a temperature of 130°C. The heat load of the reboiler 11 is 17288KW. The mixture E of trihydroxypropionaldehyde and by-products is extracted from the bottom of the trihydroxypropionaldehyde recovery tower 10, with a flow rate of 4158kg / h and a temperature of 199°C.

[0069] Table 3 Composition of recycled water obtained in Example 2

[0070] name Recycled water Temperature, °C 99.65 Pressure, MPa 0.14 Mass flow, kg / hr 38232.02 Composition, mass fraction% Water, 99.98

[0071] Compared with Comparative Example 2, this embodiment uses a heat pump distillation process to convert the heat of low-grade overhead distillate I into high-grade heat, and through heat integration within the system, fully utilizes the energy within the system, only increases power consumption by 456kW, and reduces steam load by 33550KW, thereby significantly reducing the operating cost of the device.

[0072] Comparative Example 1

[0073] A plate distillation tower is directly used to separate trihydroxypropionaldehyde and water: crude trihydroxypropionaldehyde A from the upstream device enters the crude trihydroxypropionaldehyde plate separation tower, and the operating pressure of the crude trihydroxypropionaldehyde plate separation tower is 0.14MPa and the temperature is 100°C.

[0074] Crude trihydroxypropionaldehyde A enters the 10th plate of the separation tower. The theoretical plate number of the crude trihydroxypropionaldehyde separation tower is 21, and the operating pressure is 0.14MPa. Trihydroxypropionaldehyde and its by-products are produced at the bottom of the crude trihydroxypropionaldehyde plate separation tower, with a flow rate of 4158kg / h and a temperature of 169°C; 38232kg / h of recycled water is produced at the top of the tower at a temperature of 100°C.

[0075] Table 4 Comparative Example 1 Recycled Water Composition

[0076] name Recycled water Temperature, °C 127.48 Pressure, MPa 0.25 Mass flow, kg / hr 38232.02 Composition, mass fraction% Water, 99.97

[0077] The traditional separation process of trihydroxypropionaldehyde and water is to directly use a plate distillation tower to separate trihydroxypropionaldehyde and water. The heat load of the top condenser is -29008KW, and the heat load of the tower bottom reboiler is 28889KW.

[0078] Comparative Example 2

[0079] A plate distillation tower is directly used to separate trihydroxypropionaldehyde and water: crude trihydroxypropionaldehyde A from the upstream device enters the crude trihydroxypropionaldehyde plate separation tower, and the operating pressure of the crude trihydroxypropionaldehyde plate separation tower is 0.25MPa and the temperature is 126°C.

[0080] Crude trihydroxypropionaldehyde A enters the 10th plate of the separation tower. The theoretical plate number of the crude trihydroxypropionaldehyde separation tower is 20, and the operating pressure is 0.25MPa. Trihydroxypropionaldehyde and its by-products are produced at the bottom of the crude trihydroxypropionaldehyde plate separation tower, with a flow rate of 4158kg / h and a temperature of 199°C; 42812.17kg / h of recycled water is produced at the top of the tower at a temperature of 127°C.

[0081] Table 5 Composition of recycled water obtained in Comparative Example 2

[0082] name Recycled water Temperature, °C 127.48 Pressure, MPa 0.25 Mass flow, kg / hr 38232.02 Composition, mass fraction% Water, 99.97

[0083] The traditional separation process of trihydroxypropionaldehyde and water is to directly use a plate distillation tower to separate trihydroxypropionaldehyde and water. The heat load of the top condenser is -32283KW, and the heat load of the tower bottom reboiler is 32782KW.

[0084] Example 3

[0085] The crude trihydroxypropionaldehyde A from the upstream device enters the water recovery tower 1, and the operating pressure of the water recovery tower 1 is 0.14MPa and the operating temperature is 100°C.

[0086] Crude trihydroxypropionaldehyde A enters the first plate of water recovery tower 1. The theoretical number of plates of water recovery tower 1 is 16, and the operating pressure is 0.14MPa. Part of crude trihydroxypropionaldehyde is extracted from the bottom of water recovery tower 1, with a flow rate of 53470kg / hr. It is first reduced to 0.12MPa by pressure reducing valve 2, and then passes through heat exchanger 3 to exchange heat of 12451.7KW before entering trihydroxypropionaldehyde water separation tank 4. The water vapor phase ID extracted from the top of trihydroxypropionaldehyde water separation tank 4 enters compressor 5 and is compressed to 0.14MPa. Finally, it exchanges heat of 532.8KW through bottom condenser 6, and returns to the 17th plate of water recovery tower after cooling to 105°C, with a flow rate of 23836.9kg / h.

[0087] The top distillate IB of the water recovery tower has a flow rate of 45829 kg / hr, enters the heat exchanger 3 to provide heat for the crude trihydroxypropionaldehyde, exchanging 12451.7 kW of heat, and enters the top condenser 7 in turn after heat exchange, with a heat load of -11398.6 kW, and is cooled to 100°C. Part of the water vapor phase II is extracted through the water separator 8 with a flow rate of 38233 kg / h, and the remaining water vapor phase II is circulated back to the first plate of the water recovery tower 1 with a flow rate of 7596 kg / h.

[0088] The mixture E of trihydroxypropionaldehyde and by-products extracted from the bottom of the trihydroxypropionaldehyde water separation tank 4 enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, and enters the first plate of the trihydroxypropionaldehyde tower 10, with a flow rate of 29632.8 kg / h. The distillate II F at the top of the trihydroxypropionaldehyde reflux tower 10 enters the 17th plate of the water recovery tower 1 for heating, with a flow rate of 25475 kg / h and a temperature of 105°C. The heat load of the reboiler 11 is 13697.9 kW. The mixture E of trihydroxypropionaldehyde and by-products is extracted from the bottom of the trihydroxypropionaldehyde recovery tower 10, with a flow rate of 4058 kg / h and a temperature of 174°C.

[0089] Table 6 Composition of recycled water obtained in Comparative Example 3

[0090] name Recycled water Temperature, °C 101.45 Pressure, MPa 0.14 Mass flow, kg / hr 39232.02 Composition, mass fraction% Water, 97.97

[0091] Example 3 studies the influence of the operating temperature of the water recovery tower 1 on the technical effect of the present scheme. Compared with Example 1, Example 3 lowers the operating temperature of the water recovery tower 1. When the operating temperature of the water recovery tower 1 is 100°C, the composition of the recovered water is compared with that of Example 1, and it is found that the mass fraction of the recovered water is reduced, the separation effect is reduced, and the actual energy saving efficiency is also reduced, which is reduced by 13.30%, close to the required range of heat pump thermal coupling.

[0092] Example 4

[0093] The crude trihydroxypropionaldehyde A from the upstream device enters the water recovery tower 1, and the operating pressure of the water recovery tower 1 is 0.14MPa and the temperature is 135°C.

[0094] Crude trihydroxypropionaldehyde A enters the first plate of water recovery tower 1. The theoretical number of plates of water recovery tower 1 is 16, and the operating pressure is 0.14MPa. Part of crude trihydroxypropionaldehyde is extracted from the bottom of water recovery tower 1, with a flow rate of 53470kg / hr. It is first reduced to 0.12MPa by pressure reducing valve 2, and then passes through heat exchanger 3 to exchange heat of 12451.7KW before entering trihydroxypropionaldehyde water separation tank 4. The water vapor phase ID extracted from the top of trihydroxypropionaldehyde water separation tank 4 enters compressor 5 and is compressed to 0.14MPa. Finally, it exchanges heat of 532.8KW through bottom condenser 6, and returns to the 17th plate of water recovery tower after cooling to 105°C, with a flow rate of 23836.9kg / h.

[0095] The top distillate IB of the water recovery tower has a flow rate of 45829 kg / hr, enters the heat exchanger 3 to provide heat for the crude trihydroxypropionaldehyde, exchanging 12451.7 kW of heat, and enters the top condenser 7 in turn after heat exchange, with a heat load of -11398.6 kW, and is cooled to 100°C. Part of the water vapor phase II is extracted through the water separator 8 with a flow rate of 38233 kg / h, and the remaining water vapor phase II is circulated back to the first plate of the water recovery tower 1 with a flow rate of 7596 kg / h.

[0096] The mixture E of trihydroxypropionaldehyde and by-products extracted from the bottom of the trihydroxypropionaldehyde water separation tank 4 enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, and enters the first plate of the trihydroxypropionaldehyde tower 10, with a flow rate of 29632.8 kg / h. The distillate II F at the top of the trihydroxypropionaldehyde reflux tower 10 enters the 17th plate of the water recovery tower 1 for heating, with a flow rate of 25475 kg / h and a temperature of 105°C. The heat load of the reboiler 11 is 13697.9 kW. The mixture E of trihydroxypropionaldehyde and by-products is extracted from the bottom of the trihydroxypropionaldehyde recovery tower 10, with a flow rate of 4058 kg / h and a temperature of 174°C.

[0097] Table 7 Composition of recycled water obtained in Comparative Example 4

[0098] name Recycled water Temperature, °C 101.45 Pressure, MPa 0.14 Mass flow, kg / hr 39232.02 Composition, mass fraction% Water, 97.97

[0099] Example 4 also studies the influence of the temperature of the water recovery tower 1 on the technical effect of the present solution. Compared with Example 1, Example 4 increases the operating temperature of the water recovery tower 1. When the operating temperature of the water recovery tower 1 is 135°C, the composition of the recovered water is compared with that of Example 1, and it is found that the mass fraction of the recovered water is reduced, the separation effect is reduced, and the actual energy saving efficiency is reduced by 13.80%, which is close to the required range of heat pump thermal coupling.

[0100] Example 5

[0101] The results of the laboratory test were used to compare this scheme, and the composition of the crude trihydroxypropanal was shown in Table 8:

[0102] Table 8

[0103] name Crude trihydroxypropionaldehyde Temperature, °C 100 Pressure, MPa 0.25 Mass flow, kg / hr 3.00 Composition, water mass fraction % 75.00 Composition, trihydroxypropionaldehyde mass fraction % 25.00

[0104] The crude trihydroxypropionaldehyde A from the upstream device enters the water recovery tower 1, and the operating pressure of the water recovery tower is 0.2MPa and the temperature is 110°C.

[0105] Crude trihydroxypropionaldehyde A enters the second plate of water recovery tower 1. The theoretical number of plates of water recovery tower 1 is 5, and the operating pressure is 0.2MPa. Part of crude trihydroxypropionaldehyde is extracted from the bottom of water recovery tower 1 with a flow rate of 3.9kg / hr. It is first reduced to 0.15MPa by pressure reducing valve 2, and then passes through heat exchanger 3 to exchange heat 925.88W before entering trihydroxypropionaldehyde water separation tank 4. The water vapor phase ID extracted from the top of trihydroxypropionaldehyde water separation tank 4 enters compressor 5 and is compressed to 0.2MPa. Finally, it exchanges heat 108.52W through bottom condenser 6, and returns to the first plate of water recovery tower 1 after cooling to 122°C, with a flow rate of 1.6kg / h.

[0106] The distillate IB from the top of the water recovery tower has a flow rate of 2.8 kg / hr and enters the heat exchanger 3 to provide heat for the crude trihydroxypropionaldehyde, exchanging 925.88 W of heat. After the heat exchange, it enters the top condenser 7 in turn with a heat load of -772.76 W and is cooled to 120.27°C. Part of the water vapor phase II is extracted through the water separator 8 with a flow rate of 2.25 kg / h. The remaining water vapor phase II is circulated back to the first plate of the water recovery tower 1 with a flow rate of 0.55 kg / h.

[0107] The trihydroxypropionaldehyde water separation tank 4, the trihydroxypropionaldehyde E extracted from the bottom of the tank enters the trihydroxypropionaldehyde recovery tower 10 through the reflux pump 9, and enters the first plate of the trihydroxypropionaldehyde tower 10, with a flow rate of 2.3kg / h. The distillate II F at the top of the trihydroxypropionaldehyde reflux tower 10 enters the fifth plate of the water recovery tower 1 for heating, with a flow rate of 1.55kg / h and a temperature of 126°C. The heat load of the reboiler 11 is 954.04W. The trihydroxypropionaldehyde E is extracted from the bottom of the trihydroxypropionaldehyde recovery tower 10, with a flow rate of 0.75kg / h and a temperature of 190°C.

[0108] Table 8 Composition of recycled water obtained in Comparative Example 5

[0109] name Recycled water Temperature, °C 120.27 Pressure, MPa 0.20 Mass flow, kg / hr 2.25 Composition, mass fraction% Water, 99.99

[0110] Example 5 Compared with the above software simulation results, this comparative example can convert the heat of low-grade overhead distillate I into high-grade heat by using a heat pump distillation process, and through heat integration within the system, fully utilize the energy inside the system, only increase the power consumption by 32W, and reduce the steam load 1 efficiency by 47.78%, significantly reducing the operating cost of the device. Because the control of the distillation tower is more complicated in practice, the experimental test results of Example 5 not only prove the authenticity of the technical scheme and technical effects described in this application, but also prove that the method described in this application has good practical application value.

[0111] Based on the above embodiments and comparative examples, it can be found that:

[0112] (1) The energy utilization efficiency of the embodiment is higher. The embodiment adopts the heat pump distillation technology described in this application, which can convert the heat of the low-grade tower top distillate into high-grade heat, thereby effectively reducing the demand for external steam. For example, in Example 1, the heat pump distillation process only increased the power consumption by 350kW, but reduced the steam load by 28726kW; in Example 2, the power consumption increased by 456kW, while the steam load decreased by 33550kW. This shows that compared with the traditional distillation method, the method described in this application significantly improves the energy utilization efficiency and reduces the operating cost.

[0113] (2) The separation effect of the embodiment is better, and the quality of the recycled water in the embodiment is higher. From the composition of the recycled water, the water mass fractions in the recycled water obtained in Example 1 and Example 2 are 99.97% and 99.98%, respectively, which are higher than the recycled water quality in the comparative example. This shows that through the method described in this application and the optimization of operating conditions (such as pressure, temperature, etc.), the process in the embodiment can more effectively remove impurities and improve the purity of the target product.

[0114] (3) The embodiments have stronger operational flexibility and can adapt to different operating conditions. The embodiments show that under different operating conditions (such as different operating pressures and temperatures), by adjusting the process parameters, high separation efficiency and product quality can still be maintained. For example, Example 1 and Example 2 were operated at pressures of 0.14 MPa and 0.25 MPa, respectively, and both achieved good separation effects. This flexibility enables the process to operate stably in different production environments and is more adaptable.

[0115] (4) The energy consumption of the comparative example is relatively high. The energy consumption of the traditional distillation method is large. Comparative Examples 1 and 2 use traditional plate distillation towers for separation. This method requires a large amount of external steam to provide heat energy. For example, the heat load of the top condenser of Comparative Example 1 is -29008kW, and the heat load of the tower bottom reboiler is 28889kW; the heat load of the top condenser of Comparative Example 2 is -32283kW, and the heat load of the tower bottom reboiler is 32782kW. These data show that the energy consumption of the traditional method is much higher than the heat pump distillation process in the embodiment. Even compared with Examples 3 and 4, which are not the optimal solutions in this application, the energy consumption of Comparative Examples 1 and 2 is relatively high, which also proves that Examples 3 and 4 have the effect of reducing energy consumption, and further proves that even if the technical solution described in this application is not the optimal solution, it can achieve the effect of reducing energy consumption compared with the traditional process.

[0116] (5) Compared with Examples 1 and 2, although the separation effect of Examples 3 and 4 is relatively poor and the recovered water quality is low, their low energy consumption is better than that of Comparative Examples 1 and 2, and the water quality of the recovered water can also reach more than 97%. From the perspective of industrial application, if the production environment does not require high purity of recovered water and is cost-sensitive, low energy consumption and low cost are priority factors. Examples 3 and 4 can meet such requirements, which also shows that the method described in the present application can meet the needs of more different industrial production scenarios.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the technical solution. Ordinary technicians in this field should understand that those modifications or equivalent substitutions of the technical solution of the present application that do not depart from the purpose and scope of the technical solution of the present application should be included in the scope of the claims of the present application.

Claims

1. A device for separating water and trihydroxypropionaldehyde by heat pump distillation, characterized in that: It comprises a water recovery tower (1), a heat exchanger (3), a trihydroxyformaldehyde water separation tank (4), a compressor (5), a tower bottom condenser (6), a tower top condenser (7), a water separation tank (8), a reflux pump (9) and a trihydroxypropanal recovery tower (10); The bottom of the water recovery tower (1) is fluidly connected to the heat exchanger (3) through a pressure reducing valve (2); the heat exchanger (3) is fluidly connected to the trihydroxypropionaldehyde water separation tank (4); the top of the trihydroxypropionaldehyde water separation tank (4) obtains a water vapor phase, and the bottom of the trihydroxypropionaldehyde water separation tank (4) obtains trihydroxypropionaldehyde and by-products; the top of the trihydroxyformaldehyde water separation tank (4) is fluidly connected to the bottom condenser (6) through a compressor (5), and the bottom condenser (6) is fluidly connected to the bottom of the water recovery tower (1); the bottom of the trihydroxyformaldehyde water separation tank (4) is fluidly connected to the bottom of the trihydroxypropionaldehyde recovery tower (10) through a reflux pump (9), and the top of the trihydroxypropionaldehyde recovery tower (10) is fluidly connected to the bottom of the water recovery tower (1).

2. The device according to claim 1, characterized in that: The method further comprises a reboiler (11), and the bottom distillate of the trihydroxypropionaldehyde recovery tower (10) is returned to the bottom of the trihydroxypropionaldehyde recovery tower (10) after passing through the reboiler (11).

3. The device according to claim 1, characterized in that: A plurality of tower plates are arranged inside the water recovery tower, and the number of the tower plates is 15 to 30.

4. The device according to claim 1, characterized in that: The number of plates in the trihydroxypropionaldehyde recovery tower is 2 to 10.

5. A method for separating water and trihydroxypropionaldehyde by heat pump distillation, characterized in that: The method adopts the device described in any of claims 1 to 4, and the method specifically comprises the following circuit: Loop 1: Crude trihydroxypropionaldehyde (A) enters from the top of the water recovery tower, and the bottom material is decompressed by the pressure reducing valve (2) and then enters the heat exchanger (3) for heat exchange. After the heat exchange, it enters the trihydroxypropionaldehyde water separation tank (4) to obtain a water vapor phase I (D) and a mixture of trihydroxypropionaldehyde and by-products (E); Loop 2: The water vapor phase I obtained in loop 1 is compressed by a compressor (5) and then enters a bottom condenser (6) for cooling, and then returns to a water recovery tower (1) after cooling; Loop 3: The mixture (E) of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower (10) through a reflux pump (9); at the same time, the trihydroxypropionaldehyde recovery tower (10) supplies heat to its bottom through a reboiler; Loop 4: The top distillate I (B) of the water recovery tower (1) enters the heat exchanger (3) for heat exchange and provides heat for the bottom of the water recovery tower (1). After the heat exchange, the top distillate I enters the top condenser (7) for cooling and then enters the water separation tank (8) for separation. The bottom of the water separation tank (8) produces recovered water (C), and the top produces water vapor phase II which enters the water recovery tower (1) from the top of the tower. Loop 5: The top distillate II (F) produced from the top of the trihydroxypropionaldehyde recovery tower (10) enters the water recovery tower (1) from the bottom of the tower, and the bottom product (G) enters the subsequent separation device.

6. The method according to claim 5, characterized in that: The operating temperature of the water recovery tower (1) is 100°C to 135°C, and the operating pressure is -0.05MPa to 1MPa.

7. The method according to claim 6, characterized in that: The operating pressure of the water recovery tower is -0.05MPa~0.3MPa, the top temperature is 80℃~90℃, and the bottom temperature is 90℃~120℃; in loop 2, the position where the water gas phase I enters the water recovery tower is the position of the first tower plate in the tower.

8. The method according to claim 5, characterized in that: The operating pressure of the trihydroxypropionaldehyde recovery tower (10) is -0.05MPa to 0.3MPa, the tower top temperature is 100°C to 120°C, and the tower bottom temperature is 140°C to 180°C; in loop 3, the position where the mixture of trihydroxypropionaldehyde and by-products obtained in loop 1 enters the trihydroxypropionaldehyde recovery tower is the position of the first tower plate in the tower.

9. The method according to claim 5, characterized in that: The outlet pressure of the compressor is 0.1MPa-0.2MPa, and the outlet temperature is 110°C-130°C.

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