Evaporative crystallization system for tryptophan mvr

Abstract

The utility model discloses a tryptophan MVR evaporation crystallization system, including one -effect evaporator, two -effect evaporator and single -effect evaporator who links the communication in proper order along the material flow direction, adopt double -effect evaporator to combine single -effect evaporator to tryptophan solution and carry out evaporation crystallization, when tryptophan solution concentration low boiling point is low, adopt double -effect evaporator evaporation crystallization, when tryptophan solution concentration high boiling point is high, adopt single -effect evaporator evaporation crystallization, and the evaporation technology that double -effect evaporator combines single -effect evaporator can effectively reduce the steam utilization amount, improve evaporation efficiency and evaporation effect, reduce the cost. The utility model discloses double -effect evaporator and single -effect evaporator all adopt the central circulation pipe type evaporator of adding agitator, and the central circulation pipe type evaporator can realize self -circulation evaporation after solution is heated, need not set up circulating pump additionally, in addition, the central circulation pipe type evaporator adds agitator, improves the solution flowability, avoids the deposit, reduces the blockage.

Description

Technical Field

[0001] This utility model relates to the field of tryptophan production technology, specifically to a tryptophan MVR evaporation crystallization system. Background Technology

[0002] L-Tryptophan is one of the eight essential amino acids required for human and animal life activities. It plays a vital role in the growth, development, and metabolism of humans and animals, and is known as the second essential amino acid. It is widely used in the pharmaceutical, food, and feed industries. The most common method for producing L-Tryptophan is microbial fermentation. The main processes include fermentation, filtration, sterilization, decolorization, concentration, crystallization, centrifugation, and drying. Specifically, the fermentation broth containing L-Tryptophan produced by microbial fermentation is filtered, sterilized, and decolorized to obtain a clear solution containing L-Tryptophan. The concentration of the L-Tryptophan solution is approximately 1.5% to 2.5%, which is very low. Therefore, the L-Tryptophan solution must undergo a concentration and crystallization process to form a crystal slurry. This crystal slurry is then centrifuged and dried to obtain L-Tryptophan crystals.

[0003] Currently, when producing L-tryptophan using microbial fermentation, a multi-effect evaporation system is typically used to concentrate and crystallize the L-tryptophan solution. However, due to the low concentration and high water content of the L-tryptophan solution, evaporation and concentration are difficult, requiring a large amount of high-temperature steam. Furthermore, the boiling point of L-tryptophan solution increases with increasing concentration. A multi-effect evaporation system consists of multiple evaporators connected in series. The first-effect evaporator uses high-temperature live steam as a heat source to evaporate, concentrate, and crystallize the L-tryptophan solution. Subsequent evaporators use secondary steam generated by the preceding evaporator as their heat source. In this evaporation, concentration, and crystallization method, the temperature of the live steam in the first-effect evaporator is the highest, while the temperature of the secondary steam in subsequent evaporators decreases with each effect. However, the concentration of the L-tryptophan solution increases with each effect, and consequently, the boiling point increases with each effect. The secondary steam entering the last-effect evaporator has the lowest temperature, while the solution entering the last-effect evaporator has the highest boiling point. This low heat source temperature coupled with a high boiling point results in poor evaporation performance, low evaporation efficiency, and difficulty in evaporation. To ensure the evaporation effect of the multi-effect evaporation system, current technicians typically increase the supply of high-temperature steam entering the system, further increasing steam consumption, increasing the cost of L-tryptophan solution concentration and crystallization, and significantly increasing the production cost of L-tryptophan. Utility Model Content

[0004] In summary, to overcome the shortcomings of existing technologies, this invention provides a tryptophan MVR evaporation and crystallization system. This system utilizes MVR mechanical vapor recompression technology, employing a combination of a double-effect evaporator and a single-effect evaporator to evaporate and crystallize the tryptophan solution. When the tryptophan concentration is low and the boiling point is low, a double-effect evaporator is used for evaporation and crystallization; when the tryptophan concentration is high and the boiling point is high, a single-effect evaporator is used. This combined evaporation process effectively reduces the amount of live steam used, improves evaporation efficiency and effect, and lowers costs.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A tryptophan MVR evaporation crystallization system, comprising a first-effect evaporator, a second-effect evaporator, and a single-effect evaporator connected in series along the material flow direction. The inlet of the single-effect evaporator is connected to the outlet of the feed pump, and the inlet of the feed pump is connected to the raw material tank storing low-concentration tryptophan. The outlet of the single-effect evaporator is connected to the inlet of the discharge pump, and the outlet of the discharge pump is connected to the single-effect discharge pipeline. The air inlet of the first-effect evaporator and the air inlet of the single-effect evaporator are both connected to a compressed steam pipeline, which is connected to the air outlet of a steam compressor. The air outlet of the first-effect evaporator is connected to the air inlet of the second-effect evaporator, and the air outlets of the second-effect evaporator and the single-effect evaporator are both connected to the air inlet of a steam compressor. The non-condensable gas outlet of the first-effect evaporator is connected to the inlet of the second-effect evaporator. The non-condensable gas outlets of both the second-effect evaporator and the single-effect evaporator are connected to the inlet of the condenser. The outlet of the condenser is connected to the inlet of the vacuum pump, and the outlet of the vacuum pump is used for venting. The compressed steam pipeline is connected to a steam source via a live steam pipeline. The condensate outlets of the first-effect evaporator, the second-effect evaporator, the single-effect evaporator, and the condenser are all connected to the inlet of the condensate tank. The outlet of the condensate tank is connected to the inlet of the condensate pump, and the outlet of the condensate pump is connected to the condensate delivery pipeline.

[0006] Furthermore, the outlet of the feed pump is connected to the inlet of the first preheater through a feed pipeline, the outlet of the first preheater is connected to the inlet of the second preheater, the outlet of the second preheater is connected to the inlet of the first-effect evaporator through a first-effect feed pipeline, the inlet of the preheating medium of the second preheater is connected to the condensate delivery pipeline through a preheating pipeline, the outlet of the preheating medium of the second preheater is connected to the inlet of the preheating medium of the first preheater, and the outlet of the preheating medium of the first preheater is connected to the drain pipeline. A preheating valve and a preheating flow meter are installed on the preheating pipeline.

[0007] Furthermore, the first-effect feed pipeline is equipped with a first-effect feed valve and a first-effect flow meter, and the first-effect evaporator is equipped with a first-effect level gauge to monitor the liquid level inside the first-effect evaporator. The first-effect level gauge is electrically connected to the first-effect feed valve, and the first-effect feed valve is controlled and adjusted through the first-effect level gauge.

[0008] Furthermore, the outlet of the first-effect evaporator is connected to the inlet of the first-effect conveying pump, the outlet of the first-effect conveying pump is connected to the first-effect discharge pipeline, the first-effect discharge pipeline is connected to the first-effect return pipeline and the second-effect feed pipeline, the first-effect return pipeline is connected to the return port of the first-effect evaporator, and a first-effect return valve is installed on the first-effect return pipeline, the second-effect feed pipeline is connected to the inlet of the second-effect evaporator, and a second-effect feed valve is installed on the second-effect feed pipeline, the second-effect evaporator is equipped with a second-effect level gauge for monitoring the liquid level inside the second-effect evaporator, the second-effect level gauge is electrically connected to the second-effect feed valve, and the second-effect feed valve is controlled and adjusted by the second-effect level gauge.

[0009] Furthermore, the outlet of the double-effect evaporator is connected to the inlet of the double-effect conveying pump, the outlet of the double-effect conveying pump is connected to the double-effect discharge pipeline, the double-effect discharge pipeline is connected to the double-effect return pipeline and the single-effect feed pipeline respectively, the double-effect return pipeline is connected to the return port of the double-effect evaporator, and a double-effect return valve is installed on the double-effect return pipeline, the single-effect feed pipeline is connected to the inlet of the single-effect evaporator, and a single-effect feed valve is installed on the single-effect feed pipeline, the single-effect evaporator is equipped with a single-effect level gauge to monitor the liquid level inside the single-effect evaporator, the single-effect level gauge is electrically connected to the single-effect feed valve, and the single-effect feed valve is controlled and adjusted by the single-effect level gauge.

[0010] Furthermore, the single-effect discharge pipeline is connected to the return port of the single-effect evaporator via the single-effect return pipeline. A single-effect return valve is installed on the single-effect return pipeline. The single-effect discharge pipeline is connected to the discharge pipeline. A discharge valve and a discharge mass flow meter are installed on the discharge pipeline. A mass density meter for monitoring the discharge concentration is installed on the single-effect discharge pipeline. The mass density meter is electrically connected to the discharge valve, and the discharge valve is adjusted by controlling the discharge concentration.

[0011] Furthermore, the inlet of the feed pump is connected to a raw material tank storing low-concentration tryptophan via a material pipeline, and a material valve is installed on the material pipeline. The inlet of the feed pump is connected to a cleaning water tank via a cleaning pipeline, and a cleaning valve is installed on the cleaning pipeline. The outlet of the first-effect evaporator is connected to the inlet of the cleaning drainage pump via a first-effect cleaning drainage pipeline, and a first-effect drain valve is installed on the first-effect cleaning drainage pipeline. The outlet of the second-effect evaporator is connected to the inlet of the cleaning drainage pump via a second-effect cleaning drainage pipeline, and a second-effect drain valve is installed on the second-effect cleaning drainage pipeline. The outlet of the single-effect evaporator is connected to the inlet of the cleaning drainage pump via a single-effect cleaning drainage pipeline, and a single-effect drain valve is installed on the single-effect cleaning drainage pipeline. The outlet of the cleaning drainage pump is connected to the raw material tank via a return material pipeline, and a return material valve is installed on the return material pipeline. The outlet of the cleaning drainage pump is connected to the cleaning water tank via a return water pipeline, and a return water valve is installed on the return water pipeline.

[0012] Furthermore, the inlet of the first-effect conveying pump is connected to the hot cleaning water tank through a first-effect hot cleaning pipeline, and a first-effect hot cleaning valve is installed on the first-effect hot cleaning pipeline. The inlet of the second-effect conveying pump is connected to the hot cleaning water tank through a second-effect hot cleaning pipeline, and a second-effect hot cleaning valve is installed on the second-effect hot cleaning pipeline. The inlet of the discharge pump is connected to the hot cleaning water tank through a single-effect hot cleaning pipeline, and a single-effect hot cleaning valve is installed on the single-effect hot cleaning pipeline.

[0013] Furthermore, a steam valve and a steam flow meter are installed on the live steam pipeline, and a first-effect pressure sensor is installed on the first-effect evaporator to monitor the pressure inside the first-effect evaporator. The first-effect pressure sensor is electrically connected to the steam valve, and the steam valve is controlled and adjusted by the pressure inside the first-effect evaporator.

[0014] Furthermore, the condensate delivery pipeline is connected to the flushing water inlet of the steam compressor through a flushing pipeline. The flushing pipeline is equipped with a flushing valve and a flushing flow meter. The flushing flow meter is electrically connected to the flushing valve, and the flushing valve is controlled and adjusted by the flushing flow meter.

[0015] Furthermore, the condenser is equipped with a condensing pressure sensor for monitoring the pressure inside the condenser. The pipe connecting the condenser's outlet to the vacuum pump's inlet is connected to a pressure regulating pipe, which is connected to the atmosphere. A pressure regulating valve is installed on the pressure regulating pipe, and the condensing pressure sensor is electrically connected to the pressure regulating valve. The pressure regulating valve is adjusted by controlling the pressure inside the condenser.

[0016] Furthermore, the single-effect evaporator, double-effect evaporator, and all three are centrally circulating tube evaporators, comprising a tank, an intermediate tube, a heating tube, an upper baffle, and a lower baffle. The lower part of the tank is equipped with an upper and lower baffle arranged vertically, and a central tube is located at the center of the lower part of the tank. The upper and lower baffles are fixedly connected to the upper and lower ends of the central tube, respectively. The upper and lower baffles and the central tube divide the inner cavity of the tank into a separation chamber, a heating chamber, and a circulation chamber. The separation chamber is the inner cavity above the upper baffle within the tank, and the heating chamber is the lower inner wall and the central circulation chamber of the tank. The cavity is formed by the outer wall of the pipe, the upper baffle, and the lower baffle. The circulation chamber is the inner cavity of the middle pipe and the inner cavity of the tank below the lower baffle. The heating chamber is equipped with a heating pipe. The upper and lower ends of the heating pipe are fixedly connected to the upper baffle and the lower baffle, respectively. The heating pipe connects the separation chamber above the upper baffle of the tank body with the circulation chamber below the lower baffle. The upper end of the separation chamber is provided with a secondary steam outlet, and the lower part of the separation chamber is provided with a feed inlet and a return outlet. The heating chamber is provided with an air inlet, a condensate outlet, and a non-condensable gas outlet that communicate with the heating chamber. The lower end of the tank body is provided with a discharge outlet.

[0017] Furthermore, the tank is equipped with a stirring device, which includes stirring blades, a stirring shaft, and a stirring power device. The stirring blades are located in the lower part of the intermediate tube, and the stirring shaft enters the tank from the lower end of the tank. Its upper end is connected to the stirring blades located in the intermediate tube, and the lower end of the stirring shaft is located on the outer side of the lower end of the tank and connected to the output shaft of the stirring power device.

[0018] Furthermore, a scraper is provided in the circulation chamber below the lower partition of the tank body. The scraper is fixedly connected to the stirring shaft and is in contact with the inner bottom surface of the tank body.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. This utility model utilizes MVR (Mechanical Vapor Recompression) technology, employing a combination of a double-effect evaporator and a single-effect evaporator to evaporate and crystallize tryptophan solution. When the tryptophan solution concentration is low and the boiling point is low, a double-effect evaporator is used for evaporation and crystallization; when the tryptophan solution concentration is high and the boiling point is high, a single-effect evaporator is used for evaporation and crystallization. The evaporation process combining the double-effect and single-effect evaporators can effectively reduce the amount of live steam used, improve evaporation efficiency and evaporation effect, and reduce costs.

[0021] 2. Both the double-effect evaporator and the single-effect evaporator of this utility model adopt a central circulation tube evaporator with an agitator. The central circulation tube evaporator can achieve self-circulation evaporation after the solution is heated, without the need for an additional circulation pump. In addition, the agitator installed in the central circulation tube evaporator improves the fluidity of the solution, avoids sedimentation, and reduces clogging.

[0022] 3. The central circulation tube evaporator of this utility model has a scraper fixedly connected to the stirring shaft in the circulation chamber of the tank. As the stirring shaft rotates, the scraper can scrape up the tryptophan crystals that have settled on the bottom of the tank, making it difficult for the crystals in the solution to settle and effectively preventing the outlet from being blocked.

[0023] 4. This invention employs a double-effect evaporator to evaporate and crystallize low-concentration tryptophan. In the double-effect evaporator, the first-effect evaporator uses high-temperature compressed steam from the outlet of a steam compressor as a heat source to heat the solution, while the second-effect evaporator uses secondary steam from the first-effect evaporator as a heat source. After evaporation and crystallization in the double-effect evaporator, the concentration of the tryptophan solution increases, and consequently, its boiling point rises. Therefore, the increased-concentration tryptophan solution enters a single-effect evaporator for further evaporation and crystallization. The inlet of the single-effect evaporator is connected to the outlet of the steam compressor, and the steam entering the single-effect evaporator is high-temperature compressed steam. Using this high-temperature compressed steam as a heat source for evaporation and crystallization of the increased-concentration tryptophan solution results in a high heat source temperature, fast evaporation rate, and high evaporation efficiency. The evaporation system combining a double-effect evaporator and a single-effect evaporator effectively improves production efficiency and reduces costs.

[0024] 5. The inlet of the feed pump of this utility model is connected to the cleaning water tank through a cleaning pipeline. The feed pump delivers cleaning water to the entire system, which can clean the entire system. The first-effect conveying pump, the second-effect conveying pump and the discharge pump of this utility model are connected to the hot cleaning water tank through pipelines, which can deliver hot cleaning water to the system and perform hot water cleaning on the entire system. The hot cleaning water tank and the cleaning water tank can perform chemical cleaning or hot water cleaning on the system as needed or at regular intervals, reducing cleaning time and cleaning costs, avoiding serious scaling and blockage, and ensuring the safety and stability of the system.

[0025] 6. This invention controls the feed valve of the first-effect evaporator by adjusting the liquid level within the first-effect evaporator. When the tryptophan solution level in the first-effect evaporator is low, the opening of the feed valve is increased; when the level is high, the opening is appropriately decreased, thereby controlling the feed flow rate. Similarly, the feed valve of the second-effect evaporator is adjusted by controlling the liquid level within the second-effect evaporator, and the feed valve of the single-effect evaporator is adjusted by controlling the liquid level within the single-effect evaporator. By controlling the feed flow rate, a constant liquid level is maintained in each evaporator. The discharge pipeline of this invention is equipped with a discharge mass flow meter and a discharge valve, and the single-effect discharge pipeline is equipped with a mass density meter to monitor the discharge concentration. The discharge valve is adjusted by controlling the discharge concentration. This invention has a high degree of automation; the cooperation between the sensors and valves at various control points enables automatic operation and automatic cleaning.

[0026] 7. This utility model has a simple structure, is easy to use, has low cost and high degree of automation. It can effectively realize the evaporation and crystallization of low-concentration tryptophan solution. Compared with the existing triple-effect evaporation system used for tryptophan solution, it has low evaporation energy consumption, good crystallization effect, high evaporation efficiency, low production cost and is not easy to clog pipes. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of the central circulation tube evaporator of this utility model. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a tryptophan MVR evaporation crystallization system includes a first-effect evaporator 7, a second-effect evaporator 10, and a single-effect evaporator 14 connected in series along the material flow direction; a raw material tank 1 for storing low-concentration tryptophan; the outlet of the raw material tank 1 is connected to the inlet of a feed pump 3 via a material pipeline; a material valve 2 is installed on the material pipeline; the outlet of the feed pump 3 is connected to the inlet of a first preheater 4 via a feed pipeline; the outlet of the first preheater 4 is connected to the inlet of a second preheater 5; and the outlet of the second preheater 5 is connected to the inlet of the first-effect evaporator 7 via a first-effect feed pipeline. The feed pipeline is equipped with a first-effect feed valve 6 and a first-effect flow meter. The first-effect evaporator 7 is equipped with a first-effect level gauge 8 to monitor the liquid level inside the first-effect evaporator 7. The first-effect level gauge 8 is electrically connected to the first-effect feed valve 6. The first-effect feed valve 6 is controlled and adjusted by the first-effect level gauge 8. The preheating medium inlet of the second preheater 5 is connected to the condensate delivery pipeline 34 through the preheating pipeline. The preheating medium outlet of the second preheater 5 is connected to the preheating medium inlet of the first preheater 4. The preheating medium outlet of the first preheater 4 is connected to the drain pipeline. The preheating pipeline is equipped with a preheating valve 51 and a preheating flow meter.

[0030] The outlet of the first-effect evaporator 7 is connected to the inlet of the first-effect conveying pump 9, and the outlet of the first-effect conveying pump 9 is connected to the first-effect discharge pipeline. The first-effect discharge pipeline is connected to the first-effect return pipeline and the second-effect feed pipeline. The first-effect return pipeline is connected to the return port of the first-effect evaporator 7, and a first-effect return valve 54 is installed on the first-effect return pipeline. The second-effect feed pipeline is connected to the inlet of the second-effect evaporator 10, and a second-effect feed valve 11 is installed on the second-effect feed pipeline. The second-effect evaporator 10 is equipped with a second-effect level gauge 13 for monitoring the liquid level inside the second-effect evaporator 10. The second-effect level gauge 13 is electrically connected to the second-effect feed valve 11, and the second-effect feed valve 11 is controlled and adjusted by the second-effect level gauge 13. The outlet of the double-effect evaporator 10 is connected to the inlet of the double-effect conveying pump 12, and the outlet of the double-effect conveying pump 12 is connected to the double-effect discharge pipeline. The double-effect discharge pipeline is connected to the double-effect return pipeline and the single-effect feed pipeline. The double-effect return pipeline is connected to the return port of the double-effect evaporator 10, and a double-effect return valve 53 is installed on the double-effect return pipeline. The single-effect feed pipeline is connected to the inlet of the single-effect evaporator 14, and a single-effect feed valve 16 is installed on the single-effect feed pipeline. The single-effect evaporator 14 is equipped with a single-effect level gauge 15 for monitoring the liquid level inside the single-effect evaporator 14. The single-effect level gauge 15 is electrically connected to the single-effect feed valve 16, and the single-effect feed valve 16 is controlled and adjusted by the single-effect level gauge 15. The discharge port of the single-effect evaporator 14 is connected to the inlet of the discharge pump 17, and the outlet of the discharge pump 17 is connected to the single-effect discharge pipeline. The single-effect discharge pipeline is connected to the return port of the single-effect evaporator 14 through the single-effect return pipeline. A single-effect return valve 52 is installed on the single-effect return pipeline. The single-effect discharge pipeline is connected to the discharge pipeline 20 for discharge. A discharge valve 18 and a discharge mass flow meter are installed on the discharge pipeline 20. The discharge mass flow meter is electrically connected to the discharge valve 18. The discharge valve 18 is adjusted by controlling the discharge flow rate. A mass density meter 19 for detecting the discharge concentration is installed on the single-effect discharge pipeline. The mass density meter 19 detects the solution concentration in the single-effect discharge pipeline and controls the opening and closing of the discharge valve 18. When the solution concentration in the single-effect discharge pipeline reaches the discharge concentration requirement, the mass density meter 19 controls the discharge valve 18 to open for discharge.

[0031] The air inlet of the first-effect evaporator 7 and the air inlet of the single-effect evaporator 14 are both connected to the compressed steam pipeline 21, which is connected to the outlet of the steam compressor 22. The compressed steam pipeline 21 is connected to the steam source 24 via the live steam pipeline 23. A steam valve 25 and a steam flow meter are installed on the live steam pipeline 23. The first-effect evaporator 7 is equipped with a first-effect pressure sensor 26 that monitors the pressure inside the first-effect evaporator 7. The first-effect pressure sensor 26 is electrically connected to the steam valve 25, and the steam valve 25 is adjusted based on the pressure inside the first-effect evaporator 7. The air outlet of the first-effect evaporator 7 is connected to the air inlet of the second-effect evaporator 10. The air outlets of the second-effect evaporator 10 and the single-effect evaporator 14 are both connected to the steam compressor. The air inlet of the evaporator 22 is connected to the air inlet of the first-effect evaporator 7, and the non-condensable gas outlet of the first-effect evaporator 7 is connected to the air inlet of the second-effect evaporator 10. The non-condensable gas outlets of the second-effect evaporator 10 and the single-effect evaporator 14 are both connected to the air inlet of the condenser 27. The air outlet of the condenser 27 is connected to the inlet of the vacuum pump 28, and the outlet of the vacuum pump 28 is vented. A condensing pressure sensor 29 for monitoring the internal pressure of the condenser 27 is installed on the condenser 27. The pipeline connecting the air outlet of the condenser 27 and the inlet of the vacuum pump 28 is connected to a pressure regulating pipeline, which is connected to the atmosphere. A pressure regulating valve 30 is installed on the pressure regulating pipeline, and the condensing pressure sensor 29 is electrically connected to the pressure regulating valve 30. The pressure regulating valve 30 is adjusted by controlling the pressure inside the condenser 27.

[0032] The condensate outlets of the first-effect evaporator 7, the second-effect evaporator 10, the single-effect evaporator 14, and the condenser 27 are all connected to the inlet of the condensate tank 31. The outlet of the condensate tank 31 is connected to the inlet of the condensate pump 32, and the outlet of the condensate pump 32 is connected to the condensate delivery pipeline 34. The condensate tank 31 is equipped with a condensate level gauge 33 to monitor its internal liquid level. The condensate level gauge 33 is electrically connected to the condensate pump 32, and the condensate pump 32 is adjusted by controlling the liquid level in the condensate tank 31. The condensate delivery pipeline 34 is connected to the flushing water inlet of the steam compressor 22 via a flushing pipeline 35. The flushing pipeline 35 is equipped with a flushing valve 36 and a flushing flow meter 37. The flushing flow meter 37 is electrically connected to the flushing valve 36, and the flushing valve 36 is adjusted by controlling the flushing flow meter 37.

[0033] The inlet of the feed pump 3 is connected to the cleaning water tank 38 via a cleaning pipe 39, and a cleaning valve 40 is installed on the cleaning pipe 39. The outlet of the first-effect evaporator 7 is connected to the inlet of the cleaning drainage pump 41 via a first-effect cleaning drainage pipe, and a first-effect drain valve 42 is installed on the first-effect cleaning drainage pipe. The outlet of the second-effect evaporator 10 is connected to the inlet of the cleaning drainage pump 41 via a second-effect cleaning drainage pipe, and a second-effect drain valve 43 is installed on the second-effect cleaning drainage pipe. The outlet of the single-effect evaporator 14 is connected to the inlet of the cleaning drainage pump 41 via a single-effect cleaning drainage pipe, and a single-effect drain valve 44 is installed on the single-effect cleaning drainage pipe. The outlet of the cleaning drainage pump 41 is connected to the raw material tank 1 via a return material pipe, and a return material valve 45 is installed on the return material pipe. The outlet of the cleaning drainage pump 41 is connected to the cleaning water tank 38 via a return water pipe, and a return water valve 46 is installed on the return water pipe.

[0034] The inlet of the first-effect conveying pump 9 is connected to the hot cleaning water tank 47 through a first-effect hot cleaning pipeline, and a first-effect hot cleaning valve 48 is installed on the first-effect hot cleaning pipeline. The inlet of the second-effect conveying pump 12 is connected to the hot cleaning water tank 47 through a second-effect hot cleaning pipeline, and a second-effect hot cleaning valve 49 is installed on the second-effect hot cleaning pipeline. The inlet of the discharge pump 17 is connected to the hot cleaning water tank 47 through a single-effect hot cleaning pipeline, and a single-effect hot cleaning valve 50 is installed on the single-effect hot cleaning pipeline.

[0035] like Figure 2As shown, the single-effect evaporator 7, the double-effect evaporator 10, and the single-effect evaporator 14 are all centrally circulating tube evaporators, including a tank 101, an intermediate tube 102, a heating tube 103, an upper baffle 104, and a lower baffle 105. The lower part of the tank 101 is provided with the upper baffle 104 and the lower baffle 105 arranged vertically. The intermediate tube 102 is located at the center of the lower part of the tank 101. The upper baffle 104 and the lower baffle 105 are fixedly connected to the upper and lower ends of the intermediate tube 102, respectively. The upper baffle 104, the lower baffle 105, and the intermediate tube 102 divide the inner cavity of the tank 101 into a separation chamber 106, a heating chamber 107, and a circulation chamber 108. The separation chamber 106 is the inner cavity above the upper baffle 104 within the tank 101, and the heating chamber 107 is located in the lower part of the tank 101. The cavity is formed by the inner wall, the outer wall of the intermediate pipe 102, the upper partition 104, and the lower partition 105. The circulation chamber 108 is the inner cavity of the intermediate pipe 102 and the inner cavity of the tank 101 below the lower partition 105. The heating chamber 107 is provided with a heating pipe 103. The upper and lower ends of the heating pipe 103 are fixedly connected to the upper partition 104 and the lower partition 105, respectively. The heating pipe 103 connects the separation chamber 106 above the upper partition 104 of the tank 101 with the circulation chamber 108 below the lower partition 105. The upper end of the separation chamber 106 is provided with a secondary steam outlet. The lower part of the separation chamber 106 is provided with a feed inlet and a return outlet. The heating chamber 107 is provided with an air inlet, a condensate outlet, and a non-condensable gas outlet that communicate with the heating chamber 107. The lower end of the tank 101 is provided with a discharge outlet. A stirring device is provided on the tank body 101. The stirring device includes stirring blades 111, stirring shaft 110, and stirring power device 109. The stirring blades 111 are located in the lower part of the intermediate tube 102. The stirring shaft 110 enters the tank body 101 from the lower end, and its upper end is connected to the stirring blades 111 located in the intermediate tube 102. The lower end of the stirring shaft 110 is located on the outer side of the lower end of the tank body 101 and is connected to the output shaft of the stirring power device 109. A scraper 112 is provided in the circulation chamber 108 below the lower partition 105 in the tank body 101. The scraper 112 is fixedly connected to the stirring shaft 110 and is in contact with the inner bottom surface of the tank body 101.

[0036] During initial system startup, since no material enters the first-effect evaporator 7, the second-effect evaporator 10, and the single-effect evaporator 14, and no secondary steam is generated, the steam compressor 22 cannot provide high-temperature compressed steam. At this time, the first-effect evaporator 7 and the single-effect evaporator 14 use the live steam provided by the steam source 24 as their heat source. The vacuum pump 28 is then started, and the live steam provided by the steam source 24 enters the compressed steam pipeline 21 along the live steam pipeline 23, and then enters the first-effect evaporator 7 and the single-effect evaporator 14 along the compressed steam pipeline 21. Open material valve 2, first-effect feed valve 6, and start feed pump 3. The low-concentration tryptophan solution in raw material tank 1 enters the first preheater 4, second preheater 5, and first-effect evaporator 7 sequentially under the action of feed pump 3. Since no condensate is generated during the initial start-up of the system, the first preheater 4 and second preheater 5 cannot preheat the material. The low-concentration tryptophan solution entering the first-effect evaporator 7 is heated by live steam, and the water in the solution evaporates. The solution undergoes its first evaporation and crystallization in the first-effect evaporator 7. The evaporated secondary steam enters the second-effect evaporator 10. After evaporation and crystallization in the first-effect evaporator 7, the concentration increases and it enters the second-effect evaporator 10. In the second-effect evaporator 10, the secondary steam heats the solution, and the solution undergoes its second evaporation and crystallization, increasing the concentration again. Then the solution enters the single-effect evaporator 14, which uses live steam as a heat source to carry out the third evaporation and crystallization of the solution.

[0037] The secondary steam separated from the double-effect evaporator 10 and the single-effect evaporator 14 enters the steam compressor 22 along the secondary steam pipeline. The steam compressor 22 compresses and heats the secondary steam, and the generated high-temperature compressed steam enters the compressed steam pipeline 21. The high-temperature compressed steam then re-enters the first-effect evaporator 7 and the single-effect evaporator 14 along the compressed steam pipeline 21 to heat the solution. As the system operates, more and more secondary steam enters the steam compressor 22, and more and more high-temperature compressed steam is generated. Once the system operation is stable, the high-temperature compressed steam alone can meet the system's needs, and the live steam provided by the steam source 24 can be used only as supplementary steam.

[0038] After the system stabilizes, the low-concentration tryptophan solution in raw material tank 1 enters the tube side of the first preheater 4 under the action of feed pump 3, where it exchanges heat with the condensate in the shell side of the first preheater 4. After the condensate cools down, it is discharged, and the tryptophan solution absorbs the heat from the condensate and heats up. The tryptophan solution is preheated for the first time. After that, the tryptophan solution enters the tube side of the second preheater 5 and exchanges heat with the condensate in the shell side of the second preheater 5. Since the condensate enters the second preheater 5 first and then the first preheater 4, the temperature of the condensate in the second preheater 5 is higher than that in the first preheater 4. Therefore, the tryptophan solution is reheated in the second preheater 5, and the tryptophan solution is preheated for the second time.

[0039] The preheated tryptophan solution enters the first-effect evaporator 7 via the first-effect feed pipe. Inside the first-effect evaporator 7, high-temperature compressed steam evaporates and crystallizes the tryptophan solution, increasing its concentration. The liquid level in the second-effect evaporator 10 remains constant. When no feeding is needed, the first-effect transfer pump 9 re-enters the solution flowing from the outlet of the first-effect evaporator 7 via the first-effect return pipe, continuing heating and evaporation for crystallization. When the liquid level in the second-effect evaporator 10 falls below the set level, the second-effect level gauge 13 controls the second-effect feed valve 11 to open. The tryptophan solution flowing from the outlet of the first-effect evaporator 7, under the action of the first-effect transfer pump 9, enters the second-effect evaporator 10 via the second-effect feed pipe. The secondary steam separated from the first-effect evaporator 7 enters the second-effect evaporator 10, where it heats the tryptophan solution, causing it to evaporate and crystallize again, further increasing its concentration.

[0040] When the liquid level in the single-effect evaporator 14 decreases, the single-effect level gauge 15 controls the single-effect feed valve 16 to open. The tryptophan solution discharged from the second-effect evaporator 10 enters the single-effect evaporator 14 along the single-effect feed pipeline. The high-temperature compressed steam from the steam compressor 22, after being pressurized and heated, enters the single-effect evaporator 14 along the compressed steam pipeline 21. Inside the single-effect evaporator 14, the high-temperature compressed steam heats the tryptophan solution, causing it to evaporate and crystallize. Due to the high concentration of the tryptophan solution entering the single-effect evaporator 14, its boiling point is correspondingly higher. Therefore, the single-effect evaporator 14 uses high-temperature compressed steam to evaporate and concentrate the crystal slurry, which can meet the boiling point requirements. The crystal slurry flowing out of the outlet of the single-effect evaporator 14 flows out along the single-effect discharge pipeline under the action of the discharge pump 17. The single-effect discharge pipeline is equipped with a mass density meter 19 to detect the concentration of the crystal slurry. When the concentration of the crystal slurry reaches the required level, the discharge valve 18 is opened and the crystal slurry is discharged along the discharge pipeline 20. When the concentration of the crystal slurry does not reach the required level, the crystal slurry re-enters the single-effect evaporator 14 along the single-effect return pipeline to continue evaporation and crystallization.

[0041] After the crystal slurry from the single-effect evaporator 14 is discharged from the discharge pipe 20, the liquid level in the single-effect evaporator 14 drops. The single-effect level gauge 15 controls the single-effect feed valve 16 to open. The tryptophan solution in the second-effect evaporator 10 enters the single-effect evaporator 14 along the single-effect feed pipe, causing the liquid level in the second-effect evaporator 10 to drop. The second-effect level gauge 13 controls the second-effect feed valve 11 to open. The tryptophan solution in the first-effect evaporator 7 enters the second-effect evaporator 10 along the second-effect feed pipe, causing the liquid level in the first-effect evaporator 7 to drop. The first-effect level gauge 8 controls the first-effect feed valve 6 to open, and the feed pump 3 feeds the first-effect evaporator 7. The interlocking of the level gauge and the feed valve achieves a constant liquid level in the system, maintaining system stability.

[0042] The non-condensable gas discharged from the non-condensable gas outlet of the first-effect evaporator 7 enters the second-effect evaporator 10, where it participates in the evaporation and crystallization of the solution, realizing the recovery and utilization of heat in the non-condensable gas of the first effect. The non-condensable gas discharged from the non-condensable gas outlet of the second-effect evaporator 10 and the non-condensable gas outlet of the single-effect evaporator 14 enters the shell side of the condenser 27, and the circulating cooling water enters the tube side of the condenser 27. The condenser 27 uses the circulating cooling water to condense the non-condensable gas. After the non-condensable gas is cooled down, it is vented under the action of the vacuum pump 28, and the condensed water enters the condensate tank 31 for storage.

[0043] The condensate outlets of the first-effect evaporator 7, the second-effect evaporator 10, the single-effect evaporator 14, and the condensate outlet of the condenser 27 are all connected to the inlet of the condensate tank 31. The condensate tank 31 collects and stores condensate. Under the action of the condensate pump 32, the condensate in the condensate tank 31 enters the preheating pipeline and the flushing pipeline 35 along the condensate delivery pipeline 34. The preheating valve 51 is opened, and the condensate delivered by the condensate delivery pipeline 34 enters the second preheater 5 to preheat the low-concentration tryptophan solution for the second time. After that, the condensate enters the first preheater 4 to preheat the low-concentration tryptophan solution for the first time. The flushing valve 36 is opened, and the blades of the steam compressor 22 are flushed with condensate. The flushed condensate and the condensate in the secondary steam pipeline enter the compressor drain tank, and then re-enter the condensate tank 31 under the action of the compressor drain pump.

[0044] When the system experiences slight scaling or reaches its scheduled cleaning cycle, close material valve 2. Once the discharge pump 17 stops discharging slurry, open the first-effect drain valve 42, the second-effect drain valve 43, and the single-effect drain valve 44. Open the cleaning drain pump 41 and the return valve 45. The residual material in the pipes and evaporators returns to the raw material tank 1 via the return pipeline under the action of the cleaning drain pump 41, thus recovering the residual material. Then, open the cleaning valve 40 and the return water valve 46, and close the return valve 45. The cleaning water in the cleaning water tank 38 enters the system under the action of the feed pump 3. The cleaning water flows through the system to clean it, and then returns to the cleaning water tank 38 via the return pipeline under the action of the cleaning drain pump 41. After cleaning, close all valves. When hot water is needed for system cleaning, open the first-effect hot cleaning valve 48, the second-effect hot cleaning valve 49, and the single-effect hot cleaning valve 50. The hot cleaning water in the hot cleaning water tank 47 enters the system to flush it with hot water.

[0045] In this embodiment, the condenser 27 is equipped with a condensing pressure sensor 29 for monitoring the shell-side pressure, and a pressure regulating valve 30 is provided on the pressure regulating pipeline. The pressure regulating valve 30 is adjusted by controlling the shell-side pressure of the condenser 27, and outside air enters the shell side of the condenser 27 through the pressure regulating pipeline, thereby maintaining the shell-side pressure of the condenser 27 stable, that is, maintaining the system pressure stable.

[0046] It should be noted that the above-described embodiments are illustrative of the technical solutions of the present invention and not limiting thereof. Equivalent substitutions or other modifications made by those skilled in the art based on the prior art, as long as they do not exceed the concept and scope of the technical solutions of the present invention, should be included within the scope of the claims of the present invention.

Claims

1. A tryptophan MVR evaporation crystallization system, characterized in that: It includes a single-effect evaporator (7), a double-effect evaporator (10), and a single-effect evaporator (14) connected in series along the material flow direction. The inlet of the single-effect evaporator (7) is connected to the outlet of the feed pump (3), and the inlet of the feed pump (3) is connected to the raw material tank (1) storing low-concentration tryptophan. The outlet of the single-effect evaporator (14) is connected to the inlet of the discharge pump (17), and the outlet of the discharge pump (17) is connected to the single-effect discharge pipeline. The air inlet of the first-effect evaporator (7) and the air inlet of the single-effect evaporator (14) are both connected to the compressed steam pipeline (21), which is connected to the air outlet of the steam compressor (22). The air outlet of the first-effect evaporator (7) is connected to the air inlet of the second-effect evaporator (10), and the air outlets of the second-effect evaporator (10) and the single-effect evaporator (14) are both connected to the air inlet of the steam compressor (22). The non-condensable gas outlet of the first-effect evaporator (7) is connected to the inlet of the second-effect evaporator (10). The non-condensable gas outlets of the second-effect evaporator (10) and the single-effect evaporator (14) are both connected to the inlet of the condenser (27). The outlet of the condenser (27) is connected to the inlet of the vacuum pump (28), and the outlet of the vacuum pump (28) is vented. The compressed steam pipeline (21) is connected to the steam source (24) through the live steam pipeline (23). The condensate outlets of the first-effect evaporator (7), the second-effect evaporator (10), the single-effect evaporator (14), and the condenser (27) are all connected to the inlet of the condensate tank (31). The outlet of the condensate tank (31) is connected to the inlet of the condensate pump (32), and the outlet of the condensate pump (32) is connected to the condensate delivery pipeline (34).

2. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The outlet of the feed pump (3) is connected to the inlet of the first preheater (4) through the feed pipeline. The outlet of the first preheater (4) is connected to the inlet of the second preheater (5). The outlet of the second preheater (5) is connected to the inlet of the first-effect evaporator (7) through the first-effect feed pipeline. The inlet of the preheating medium of the second preheater (5) is connected to the condensate conveying pipeline (34) through the preheating pipeline. The outlet of the preheating medium of the second preheater (5) is connected to the inlet of the preheating medium of the first preheater (4). The outlet of the preheating medium of the first preheater (4) is connected to the drain pipeline. A preheating valve (51) and a preheating flow meter are installed on the preheating pipeline.

3. The tryptophan MVR evaporation crystallization system according to claim 2, characterized in that: The first-effect feed pipeline is equipped with a first-effect feed valve (6) and a first-effect flow meter. The first-effect evaporator (7) is equipped with a first-effect level gauge (8) to monitor the liquid level inside the first-effect evaporator (7). The first-effect level gauge (8) is electrically connected to the first-effect feed valve (6). The first-effect feed valve (6) is controlled and adjusted by the first-effect level gauge (8). The outlet of the first-effect evaporator (7) is connected to the inlet of the first-effect conveying pump (9). The outlet of the first-effect conveying pump (9) is connected to the first-effect discharge pipeline. The first-effect discharge pipeline is connected to the first-effect return pipeline and the second-effect inlet pipeline. The feed pipeline is connected to the return port of the first-effect evaporator (7). A first-effect return valve (54) is installed on the first-effect return pipeline. The second-effect feed pipeline is connected to the feed port of the second-effect evaporator (10). A second-effect feed valve (11) is installed on the second-effect feed pipeline. A second-effect level gauge (13) is installed on the second-effect evaporator (10) to monitor the liquid level inside the second-effect evaporator (10). The second-effect level gauge (13) is electrically connected to the second-effect feed valve (11). The second-effect feed valve (11) is controlled and adjusted by the second-effect level gauge (13).

4. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The outlet of the double-effect evaporator (10) is connected to the inlet of the double-effect conveying pump (12), and the outlet of the double-effect conveying pump (12) is connected to the double-effect discharge pipeline. The double-effect discharge pipeline is connected to the double-effect return pipeline and the single-effect feed pipeline respectively. The double-effect return pipeline is connected to the return port of the double-effect evaporator (10). A double-effect return valve (53) is installed on the double-effect return pipeline. The single-effect feed pipeline is connected to the inlet of the single-effect evaporator (14). A single-effect feed valve (16) is installed on the single-effect evaporator (14). A single-effect level gauge (15) is installed on the single-effect evaporator (14) to monitor the liquid level inside the single-effect evaporator (14). The single-effect level gauge (15) is electrically connected to the single-effect feed valve (16). The single-effect feed valve (16) is controlled and adjusted by the single-effect level gauge (15).

5. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The single-effect discharge pipeline is connected to the return port of the single-effect evaporator (14) through the single-effect return pipeline. The single-effect return pipeline is equipped with a single-effect return valve (52). The single-effect discharge pipeline is connected to the discharge pipeline (20). The discharge pipeline (20) is equipped with a discharge valve (18) and a discharge mass flow meter. The single-effect discharge pipeline is equipped with a mass density meter (19) for monitoring the discharge concentration. The mass density meter (19) is electrically connected to the discharge valve (18). The discharge valve (18) is adjusted by controlling the discharge concentration.

6. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The inlet of the feed pump (3) is connected to the raw material tank (1) storing low-concentration tryptophan via a material pipeline. A material valve (2) is installed on the material pipeline. The inlet of the feed pump (3) is connected to the cleaning water tank (38) via a cleaning pipeline (39). A cleaning valve (40) is installed on the cleaning pipeline (39). The outlet of the first-effect evaporator (7) is connected to the inlet of the cleaning drainage pump (41) via the first-effect cleaning drainage pipeline. A first-effect drain valve (42) is installed on the first-effect cleaning drainage pipeline. The outlet of the second-effect evaporator (10) is connected to the second-effect cleaning drainage pipeline. The inlet of the cleaning drainage pump (41) is connected to the double-effect cleaning drainage pipeline, and a double-effect drain valve (43) is installed on the double-effect cleaning drainage pipeline. The outlet of the single-effect evaporator (14) is connected to the inlet of the cleaning drainage pump (41) through the single-effect cleaning drainage pipeline, and a single-effect drain valve (44) is installed on the single-effect cleaning drainage pipeline. The outlet of the cleaning drainage pump (41) is connected to the raw material tank (1) through the return material pipeline, and a return material valve (45) is installed on the return material pipeline. The outlet of the cleaning drainage pump (41) is connected to the cleaning water tank (38) through the return water pipeline, and a return water valve (46) is installed on the return water pipeline.

7. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The discharge port of the first-effect evaporator (7) is connected to the inlet of the first-effect conveying pump (9). The inlet of the first-effect conveying pump (9) is connected to the hot cleaning water tank (47) through the first-effect hot cleaning pipeline. A first-effect hot cleaning valve (48) is installed on the first-effect hot cleaning pipeline. The discharge port of the second-effect evaporator (10) is connected to the inlet of the second-effect conveying pump (12). The inlet of the second-effect conveying pump (12) is connected to the hot cleaning water tank (47) through the second-effect hot cleaning pipeline. A second-effect hot cleaning valve (49) is installed on the second-effect hot cleaning pipeline. The inlet of the discharge pump (17) is connected to the hot cleaning water tank (47) through the single-effect hot cleaning pipeline. A single-effect hot cleaning valve (50) is installed on the single-effect hot cleaning pipeline.

8. The tryptophan MVR evaporation crystallization system according to claim 1, characterized in that: The live steam pipeline (23) is equipped with a steam valve (25) and a steam flow meter. The first-effect evaporator (7) is equipped with a first-effect pressure sensor (26) to monitor the pressure inside the first-effect evaporator (7). The first-effect pressure sensor (26) is electrically connected to the steam valve (25) and the steam valve (25) is adjusted by controlling the pressure inside the first-effect evaporator (7).

9. The tryptophan MVR evaporation crystallization system according to any one of claims 1 to 8, characterized in that: The single-effect evaporator (7), the double-effect evaporator (10), and the single-effect evaporator (14) are all centrally circulating tube evaporators, including a tank (101), an intermediate tube (102), a heating tube (103), an upper baffle (104), and a lower baffle (105). The lower part of the tank (101) is provided with an upper baffle (104) and a lower baffle (105) arranged vertically. The center of the lower part of the tank (101) is provided with an intermediate tube (102). The upper partition (104) and lower partition (105) are fixedly connected to the upper and lower ends of the intermediate tube (102), respectively. The upper partition (104), lower partition (105) and intermediate tube (102) divide the inner cavity of the tank (101) into a separation chamber (106), a heating chamber (107) and a circulation chamber (108). The separation chamber (106) is the inner cavity above the upper partition (104) in the tank (101), and the heating chamber (107) is the inner cavity above the upper partition (104) in the tank (101). The cavity is formed by the lower inner wall, the outer wall of the intermediate tube (102), the upper partition (104), and the lower partition (105). The circulation chamber (108) is the inner cavity of the tank (101) below the inner cavity of the intermediate tube (102) and the lower partition (105). The heating chamber (107) is equipped with a heating tube (103). The upper and lower ends of the heating tube (103) are fixedly connected to the upper partition (104) and the lower partition (105) respectively. The separation chamber (106) above the upper partition (104) of the tank body (101) is connected to the circulation chamber (108) below the lower partition (105). The upper end of the separation chamber (106) is provided with a secondary steam outlet, and the lower part of the separation chamber (106) is provided with a feed inlet and a return outlet. The heating chamber (107) is provided with an air inlet, a condensate outlet and a non-condensable gas outlet that are connected to the heating chamber (107). The lower end of the tank body (101) is provided with a discharge outlet.

10. The tryptophan MVR evaporation crystallization system according to claim 9, characterized in that: The tank (101) is equipped with a stirring device, which includes stirring blades (111), stirring shaft (110) and stirring power device (109). The stirring blades (111) are located in the lower part of the intermediate tube (102). The stirring shaft (110) passes through the tank (101) from the lower end of the tank (101) and its upper end is connected to the stirring blades (111) located in the intermediate tube (102). The lower end of the stirring shaft (110) is located outside the lower end of the tank (101) and is connected to the output shaft of the stirring power device (109).

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