Multi-effect evaporation apparatus and maltose production plant
By combining co-current and counter-current modes in a multi-effect evaporator, the problem that existing evaporators for heat-sensitive and high-viscosity materials cannot simultaneously improve thermal energy utilization and evaporation efficiency has been solved, thus achieving efficient and low-cost maltose production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DANISCO SWEETENERS (ANYANG) CO LTD
- Filing Date
- 2025-07-07
- Publication Date
- 2026-06-05
AI Technical Summary
Existing multi-effect evaporators cannot simultaneously achieve high thermal energy utilization and high evaporation efficiency when processing heat-sensitive and high-viscosity materials such as maltose.
A multi-effect evaporation device is adopted, which combines co-current and counter-current modes. The front evaporator is in co-current mode and the rear evaporator is in counter-current mode. They are connected by a series steam pipe. Each evaporator uses the secondary steam of the previous effect as the heating medium. The material flows in opposite or the same direction in different groups of evaporators, thus optimizing the heat transfer effect.
It improves thermal efficiency and evaporation efficiency, reduces the residence time of materials in high-temperature areas, lowers energy consumption and production costs, and enhances product quality.
Smart Images
Figure CN224321028U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of evaporation equipment technology, and in particular to a multi-effect evaporation device and maltose preparation equipment. Background Technology
[0002] In industrial production, evaporators are devices that vaporize part of the solvent in a solution, separating the solute and solvent to increase the solution concentration. Multi-effect evaporators are a type of highly efficient and energy-saving evaporation equipment. By connecting multiple evaporators in series, the secondary steam generated in the first effect can be used as a heat source for the subsequent effects, significantly reducing energy consumption. Its core principle is the cascade utilization of heat; that is, after live steam enters the first-effect evaporator to heat the material, the generated secondary steam drives the subsequent first-effect evaporators, achieving the reuse of the latent heat of steam.
[0003] Based on the flow direction of materials and steam, existing multi-effect evaporators disclose two operating modes: co-current and counter-current. The co-current mode, as disclosed in Chinese Utility Model Patent CN209188148U, involves a dual single-effect series MVR evaporation system where the material is transported along the steam path. The counter-current mode, as disclosed in Chinese Utility Model Patent CN204671916U, involves a seven-effect segmented evaporator assembly for concentrating sodium aluminate solution. In this multi-effect evaporation structure, the material is divided into two parts for evaporation and concentration, reducing live steam consumption. The material's transport path in both parts is against the steam path.
[0004] The co-current mode is suitable for low-viscosity materials and has excellent thermal energy utilization because the steam and liquid flow in the same direction, conforming to the heat transfer temperature gradient, which can fully utilize the steam heat energy, improve thermal efficiency, and reduce energy consumption. However, it has the following disadvantages: 1. Poor heat transfer effect: As the liquid evaporates and concentrates in each effect, its boiling point gradually increases, while the temperature of the heating steam decreases, resulting in a gradual decrease in the heat transfer temperature difference and a gradual deterioration in the heat transfer effect. 2. Not suitable for high-viscosity materials: The flow of the liquid between effects is driven by pressure difference. For high-viscosity materials, the flow resistance is large, which may cause the material to stay in the low-temperature evaporator of the later effect for too long, affecting production efficiency. The counter-current mode is suitable for high-viscosity solutions and has the following advantages: 1. High evaporation efficiency: Because the liquid and steam flow in opposite directions, the boiling point of the liquid and the temperature difference of the heating steam in each effect are relatively stable, resulting in good heat transfer effect, which can improve evaporation efficiency and shorten evaporation time. 2. Suitable for high-viscosity materials, as the material flows from a low-temperature, low-concentration efficiency zone to a high-temperature, high-concentration efficiency zone. At high temperatures, the material viscosity decreases, improving fluidity and facilitating evaporation of high-viscosity materials. It can handle materials with various properties. However, counter-current evaporation has the disadvantage of lower thermal efficiency. Since steam and liquid flow in opposite directions, the temperature difference between them is significant in the low-temperature section, resulting in insufficient heat utilization and a slightly lower thermal efficiency than co-current evaporation. Therefore, for the evaporation of heat-sensitive and high-viscosity materials, such as maltose, currently available multi-effect evaporators cannot achieve both full utilization of thermal energy and relatively improved evaporation efficiency. Utility Model Content
[0005] In view of this, the purpose of this utility model is to provide a multi-effect evaporation device that can balance high heat utilization (reduced energy consumption) and high evaporation efficiency (shortened processing time).
[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:
[0007] A multi-effect evaporation device includes multiple evaporators connected in series. The steam outlet of the first evaporator is connected to the steam inlet of the second evaporator through a secondary steam pipe. The steam inlet of the first evaporator is connected to a primary steam pipe. According to the series sequence, the multiple evaporators located at the front constitute the first group of multi-effect evaporators, and the multiple evaporators located at the rear constitute the second group of multi-effect evaporators.
[0008] The outlet of the feed pipe of the material to be evaporated is connected to the material inlet of the first evaporator in the second group of multi-effect evaporators. The material outlet of the first evaporator in the second group of multi-effect evaporators is connected to the material inlet of the next evaporator. The material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators. The material outlet of the last evaporator in the first group of multi-effect evaporators is connected to the material inlet of the first evaporator.
[0009] More preferably, the steam outlet of the last evaporator in the second group of multi-effect evaporators is connected to the heat exchanger of the cooling water system.
[0010] More preferably, the material outlet of the foremost evaporator in the first group of multi-effect evaporators is connected to the feed inlet of the flash evaporator, a flash discharge pump is installed on the flash discharge pipe of the flash evaporator, and a mass flow meter is also installed on the flash discharge pipe.
[0011] More preferably, the flash discharge pipe is further connected to a reflux pipe and a discharge pipe after the mass flow meter. A reflux valve is installed on the reflux pipe, and a discharge valve is installed on the discharge pipe.
[0012] More preferably, the inlet of the feed pipe is connected to the pre-evaporation tank, and both the pre-evaporation tank and the flash evaporator are equipped with level gauges.
[0013] More preferably, the feed pipe is connected to an evaporation feed pump, a flow meter, and a bag filter.
[0014] More preferably, the material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators through multiple preheaters, and the material outlet of the last evaporator in the first group of multi-effect evaporators is connected to the material inlet of the previous evaporator through the preheater, wherein the preheater is a material preheater or a material preheater and a hot water preheater.
[0015] More preferably, each of the evaporators includes an evaporator body, a separator, and a discharge pump, with the middle part of the evaporator body connected to the middle part of the separator, and the lower outlet of the evaporator body and the lower outlet of the separator both connected to the discharge pump;
[0016] The steam outlet is located at the top of the separator, the steam inlet is located on the evaporator body, the material inlet is located at the top of the evaporator body, and the material outlet is located at the rear of the outlet of the discharge pump.
[0017] More preferably, the multi-effect evaporator includes nine evaporators connected in series, with the first five of the nine evaporators forming the first group of multi-effect evaporators and the last four forming the second group of multi-effect evaporators.
[0018] This utility model also provides a maltose preparation device, including the multi-effect evaporation device described in any of the preceding claims.
[0019] The multi-effect evaporation device provided by this utility model has the advantages of high thermal efficiency, high evaporation efficiency, and improved product quality. The maltose preparation equipment provided by this utility model, since it includes a multi-effect evaporation device, possesses the beneficial effects of such a device, which will not be elaborated further here. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of a multi-effect evaporation device provided in a specific embodiment of the present invention.
[0022] The following labels are shown in the attached diagram:
[0023] 1. Pre-evaporation tank; 2. Evaporation feed pump; 3. Flow meter; 4. Bag filter; 5. Feed pipe; 6. Primary steam pipe; 7. First-effect evaporator; 8. First-effect separator; 9. Second-effect evaporator; 10. Second-effect separator; 11. Third-effect evaporator; 12. Third-effect separator; 13. Fourth-effect evaporator; 14. Fourth-effect separator; 15. Fifth-effect evaporator; 16. Fifth-effect separator; 17. Sixth-effect evaporator; 18. Sixth-effect separator; 19. Seventh-effect evaporator; 20. Seventh-effect separator; 21. Eighth-effect evaporator; 22. Eighth-effect separator; 23. Ninth-effect evaporator. 24. Separator; 25. Single-effect discharge pump; 26. Double-effect discharge pump; 27. Triple-effect discharge pump; 28. Quadruple-effect discharge pump; 29. Five-effect discharge pump; 30. Six-effect discharge pump; 31. Seven-effect discharge pump; 32. Eight-effect discharge pump; 33. Nine-effect discharge pump; 34. Secondary steam pipeline; 35. Hot water preheater; 36. Material preheater; 37. Cooling water system; 38. Vacuum pump; 39. Flash evaporator; 40. Flash discharge pump; 41. Mass flow meter; 42. Reflux valve; 43. Reflux pipeline; 44. Discharge valve; 45. Discharge pipeline. Detailed Implementation
[0024] The core of this utility model is to provide a multi-effect evaporation device and a maltose preparation equipment, which effectively solves the problem that existing multi-effect evaporators cannot fully utilize thermal energy while relatively improving evaporation efficiency.
[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0026] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a multi-effect evaporation device provided in a specific embodiment of the present invention.
[0027] In one specific embodiment, the multi-effect evaporation device provided by this utility model includes multiple evaporators connected in series. The steam outlet of the preceding evaporator is connected to the steam inlet of the following evaporator via a secondary steam pipe 34. The steam inlet of the foremost evaporator is connected to a primary steam pipe and is located at the forefront in the steam supply direction. Preferably, a pressure gauge and a thermometer are installed on the primary steam pipe. According to the series sequence, the multiple evaporators at the front constitute the first group of multi-effect evaporators, and the multiple evaporators at the rear constitute the second group of multi-effect evaporators. The outlet of the feed pipe of the material to be evaporated is connected to the material inlet of the foremost evaporator in the second group of multi-effect evaporators. The material outlet of the preceding evaporator in the second group of multi-effect evaporators is connected to the material inlet of the following evaporator. The material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators. The material outlet of the following evaporator in the first group of multi-effect evaporators is connected to the material inlet of the preceding evaporator.
[0028] In the multi-effect evaporation device provided by this utility model, the material and steam flow in the same direction in the second group of multi-effect evaporators, meaning the second group of multi-effect evaporators operates in a co-current mode. In the first group of multi-effect evaporators, the material and steam flow in opposite directions, meaning the first group of multi-effect evaporators operates in a counter-current mode. Therefore, the multi-effect evaporation device in this embodiment can firstly combine the heat transfer advantages of both co-current and counter-current modes of multi-effect evaporators. In the initial co-current stage, the steam and liquid flow in the same direction, meeting the temperature gradient requirements for heat transfer, fully utilizing the steam's thermal energy, improving thermal efficiency, reducing energy consumption, and ensuring stable operation and initial utilization of thermal energy. In the subsequent counter-current stage, the liquid and steam flow in opposite directions. At higher material concentrations, the large temperature difference in counter-current evaporation heat transfer enhances heat transfer efficiency and ensures evaporation efficiency.
[0029] Secondly, the multi-effect evaporator in this embodiment combines co-current and counter-current flow. In the early stage, the advantages of co-current flow can be used to avoid excessive heating and local overheating of materials. In the later stage, counter-current flow can ensure the uniformity of product concentration. This is because high temperature can reduce the viscosity of materials, thereby helping to improve the stability of product quality.
[0030] Furthermore, in this embodiment, when the multi-effect evaporator is used for the evaporation of heat-sensitive materials and high-viscosity materials such as maltose syrup, the material first enters the effect body with a lower temperature for preliminary concentration at a low temperature, and then gradually enters the effect body with a higher temperature. This can reduce the residence time of the material in the high-temperature region, reduce the risk of material deterioration due to excessive heating time, and the material viscosity decreases and the fluidity is good at high temperatures, which is conducive to the evaporation of the material.
[0031] Therefore, the multi-effect evaporator in this embodiment has the advantages of high thermal efficiency, high evaporation efficiency, and improved product quality.
[0032] Specifically, such as Figure 1 As shown, the multi-effect evaporator provided in this embodiment includes nine evaporators connected in series. The first five evaporators form the first group of multi-effect evaporators, namely, evaporator 7 (first effect), evaporator 9 (second effect), evaporator 11 (third effect), evaporator 13 (fourth effect), and evaporator 15 (fifth effect). The last four form the second group of multi-effect evaporators, namely, evaporator 17 (sixth effect), evaporator 19 (seventh effect), evaporator 21 (eighth effect), and evaporator 23 (ninth effect). This multi-effect evaporator, by employing multi-effect evaporation, can effectively utilize secondary steam, improve thermal energy utilization, and reduce the processing cost of secondary steam.
[0033] Each evaporator includes an evaporator body, a separator, and a discharge pump. Specifically, a single-effect evaporator 7 includes a single-effect evaporator body, a single-effect separator 8, and a single-effect discharge pump 25; a double-effect evaporator 9 includes a double-effect evaporator body, a double-effect separator 10, and a double-effect discharge pump 26; a triple-effect evaporator 11 includes a triple-effect evaporator body, a triple-effect separator 12, and a triple-effect discharge pump 27; a quadruple-effect evaporator 13 includes a quadruple-effect evaporator body, a quadruple-effect separator 14, and a quadruple-effect discharge pump 28; and a five-effect evaporator... Unit 15 includes a five-effect evaporator body, a five-effect separator 16, and a five-effect discharge pump 29; Unit 17 includes a six-effect evaporator body, a six-effect separator 18, and a six-effect discharge pump 30; Unit 19 includes a seven-effect evaporator body, a seven-effect separator 20, and a seven-effect discharge pump 31; Unit 21 includes an eight-effect evaporator body, an eight-effect separator 22, and an eight-effect discharge pump 32; Unit 23 includes a nine-effect evaporator body, a nine-effect separator 24, and a nine-effect discharge pump 33.
[0034] Preferably, each evaporator is equipped with a pressure gauge on its evaporator body, and the separator is equipped with both a pressure gauge and a thermometer. A frequency converter is installed on the discharge pump. The middle section of the evaporator body connects to the middle section of the separator, and both the lower outlet of the evaporator body and the lower outlet of the separator are connected to the discharge pump. The steam outlet is located at the top of the separator, the steam inlet is located on the evaporator body, the material inlet is located at the top of the evaporator body, and the material outlet is located at the rear of the discharge pump outlet.
[0035] During operation, the first-effect evaporator 7 is connected to a primary steam pipe 6, located at the forefront of the steam supply direction. Live steam or waste heat steam serves as the heating source, entering the first-effect evaporator 7 through the primary steam pipe 6. The waste heat steam can originate from other processes. When the material enters from the top of the first-effect evaporator 7, it forms a thin film and is heated along the tube side to the solvent's boiling point, during which the solvent evaporates. The concentrated liquid and evaporated steam enter the first-effect separator 8 for vapor-liquid separation. The separated secondary steam enters the second-effect evaporator 9 through the secondary steam pipe 34 as the heating medium for the second-effect evaporator. The secondary steam generated by the second-effect evaporator 9 is used as the heating medium for the third-effect evaporator 11; the secondary steam generated by the third-effect evaporator 11 is used as the heating medium for the fourth-effect evaporator 13; the secondary steam generated by the fourth-effect evaporator 13 is used as the heating medium for the fifth-effect evaporator 15; the secondary steam generated by the fifth-effect evaporator 15 is used as the heating medium for the sixth-effect evaporator 17; the secondary steam generated by the sixth-effect evaporator 17 is used as the heating medium for the seventh-effect evaporator 19; the secondary steam generated by the seventh-effect evaporator 19 is used as the heating medium for the eighth-effect evaporator 21; and the secondary steam generated by the eighth-effect evaporator 21 is used as the heating medium for the ninth-effect evaporator 23.
[0036] In this embodiment, the material conveying direction is different from the steam transfer direction. The material enters the six-effect evaporator 17 from the pre-evaporation tank 1 through the feed pipe 5. The material enters from the top of the six-effect evaporator 17 and enters the six-effect separator 18 for vapor-liquid separation. The concentrated liquid enters the seven-effect evaporator 19 through the six-effect discharge pump 30 for further evaporation. After separation by the seven-effect separator 20, it enters the eight-effect evaporator 21, and then sequentially enters the nine-effect evaporator 23, the five-effect evaporator 15, the four-effect evaporator 13, the three-effect evaporator 11, the two-effect evaporator 9, and the one-effect evaporator 7.
[0037] In some embodiments, the steam outlet of the last evaporator in the second group of multi-effect evaporators is connected to the heat exchanger of the cooling water system 37. That is, the steam outlet of the nine-stage evaporator 23 can be connected to the heat exchanger of the cooling water system 37 to cool the cooling water. The cooling water system can also cool the vacuum pump 38 in other processes. Of course, the steam in the nine-stage evaporator 23 can also be recovered.
[0038] In some embodiments, the material outlet of the foremost evaporator in the first group of multi-effect evaporators is connected to the feed inlet of flash evaporator 39. A flash discharge pump 40 is installed on the flash discharge pipe of flash evaporator 39. The concentrate from the first-effect evaporator 7 enters flash evaporator 39 via first-effect discharge pump 25, is flashed to 70-75°C, and then sent to the downstream tank via flash discharge pump 40. A mass flow meter 41 is also installed on the flash discharge pipe. The mass flow meter 41 can display the material density and automatically adjust the feed flow rate and steam flow rate according to the material density, adjusting the solid content to the normal range in a short time.
[0039] In some embodiments, a reflux pipe 43 and a discharge pipe 45 are connected to the flash discharge pipe after the mass flow meter 41. A reflux valve 42 is installed on the reflux pipe, and a discharge valve 44 is installed on the discharge pipe 45. When evaporating the syrup, when the syrup solids content reaches the process instruction requirements of 40-50%, the discharge valve 44 can be opened and the reflux valve 42 closed to transport the material to the next process.
[0040] In some embodiments, the inlet of the feed pipe 5 is connected to the pre-evaporation tank 1, which is equipped with an agitator. Both the pre-evaporation tank and the flash evaporator are equipped with level gauges. The level gauges in both the pre-evaporation tank 1 and the flash evaporator 39 allow for real-time monitoring of the material volume within the equipment, facilitating operation and settings.
[0041] In some embodiments, an evaporation feed pump 2, a flow meter 3, and a bag filter 4 are connected to the feed pipe. The evaporation feed pump 2 is equipped with a flow meter 3, which can monitor the material feed rate and is interlocked with the first-effect evaporator 7 to automatically adjust the feed rate.
[0042] In some embodiments, the material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators via multiple preheaters. Similarly, the material outlet of the subsequent evaporator in the first group of multi-effect evaporators is connected to the material inlet of the preceding evaporator via a preheater, which is either a material preheater 36 or a combination of a material preheater 36 and a hot water preheater 35. The preheater further increases the material temperature, facilitating the adjustment of the boiling point of the material and the temperature difference between the material and the steam inside the evaporator, and also promoting solvent evaporation in the material.
[0043] During operation, when the liquid level in the pre-evaporation tank 1 reaches 35%, the agitator inside the pre-evaporation tank 1 is turned on, and then the evaporation feed pump 2 is started, allowing the material to enter the six-effect evaporator 17. When the liquid level in the six-effect evaporator 17 reaches 35%, the six-effect discharge pump 30 is started. When the liquid level in the seven-effect evaporator 19 reaches 35%, the seven-effect discharge pump 31 is started. Following the material flow, the material is sequentially pumped to the flash evaporator 39. When the liquid level in the flash evaporator 39 reaches 35%, the reflux valve 42 is opened, and the flash discharge pump 40 is started to return the material to the pre-evaporation tank 1, thus achieving material circulation. The circulating feed flow rate is controlled by adjusting the outlet regulating valve of the evaporation feed pump 2, and the stability of the liquid level in each evaporator is ensured by the interlocking of the liquid levels in each evaporator effect with the frequency converters of the discharge pumps.
[0044] In summary, the multi-effect evaporator provided in this embodiment has the functions of evaporation, separation, and reflux. By employing multi-effect evaporation, it effectively utilizes secondary steam, improves thermal energy utilization, and reduces the processing cost of secondary steam. Multiple monitoring devices can be added to each section, allowing the system to receive timely feedback and make adjustments, thereby improving evaporation quality and efficiency. The system also boasts a high degree of automation, effectively reducing labor costs.
[0045] This embodiment of the multi-effect evaporator allows for setting the material density according to product requirements during the evaporation process. Through a feedback interlock mechanism, the valves automatically adjust and control parameters such as temperature and pressure of each evaporator. Furthermore, a sight glass is installed in the evaporation heating chamber to observe the material flow status at any time.
[0046] This embodiment also provides a maltose preparation apparatus, including the multi-effect evaporator described above. Since the maltose preparation apparatus in this embodiment includes the aforementioned multi-effect evaporator, it possesses the beneficial effects of the multi-effect evaporator, which will not be elaborated further here.
[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0048] The multi-effect evaporation device and maltose preparation equipment provided by this utility model have been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model. Therefore, this utility model is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A multi-effect evaporation device, characterized in that, It includes multiple evaporators connected in series. The steam outlet of the first evaporator is connected to the steam inlet of the second evaporator through a secondary steam pipe (34). The steam inlet of the first evaporator is connected to a primary steam pipe. According to the series sequence, the multiple evaporators at the front are the first group of multi-effect evaporators, and the multiple evaporators at the rear are the second group of multi-effect evaporators. The outlet of the feed pipe (5) of the material to be evaporated is connected to the material inlet of the first evaporator of the second group of multi-effect evaporators. The material outlet of the first evaporator in the second group of multi-effect evaporators is connected to the material inlet of the second evaporator. The material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators. The material outlet of the second evaporator in the first group of multi-effect evaporators is connected to the material inlet of the first evaporator.
2. The multi-effect evaporator according to claim 1, characterized in that, The steam outlet of the last evaporator in the second group of multi-effect evaporators is connected to the heat exchanger of the cooling water system (37).
3. The multi-effect evaporator according to claim 1, characterized in that, The material outlet of the first evaporator in the first group of multi-effect evaporators is connected to the feed inlet of the flash evaporator (39). A flash discharge pump (40) is installed on the flash discharge pipe of the flash evaporator (39), and a mass flow meter (41) is also installed on the flash discharge pipe.
4. The multi-effect evaporator according to claim 3, characterized in that, The flash discharge pipe is connected to a reflux pipe (43) and a discharge pipe (45) after the mass flow meter (41). A reflux valve (42) is installed on the reflux pipe (43), and a discharge valve (44) is installed on the discharge pipe (45).
5. The multi-effect evaporator according to claim 3, characterized in that, The inlet of the feed pipe (5) is connected to the pre-evaporation tank (1), and level gauges are installed in both the pre-evaporation tank (1) and the flash evaporator (39).
6. The multi-effect evaporator according to claim 1, characterized in that, An evaporation feed pump (2), a flow meter (3), and a bag filter (4) are connected to the feed pipe.
7. The multi-effect evaporator according to claim 1, characterized in that, The material outlet of the last evaporator in the second group of multi-effect evaporators is connected to the material inlet of the last evaporator in the first group of multi-effect evaporators through multiple preheaters. The material outlet of the last evaporator in the first group of multi-effect evaporators is connected to the material inlet of the previous evaporator through the preheater. The preheater is a material preheater (36) or a material preheater (36) and a hot water preheater (35).
8. The multi-effect evaporator according to claim 1, characterized in that, Each of the evaporators includes an evaporator body, a separator, and a discharge pump. The middle part of the evaporator body is connected to the middle part of the separator, and the lower outlet of the evaporator body and the lower outlet of the separator are both connected to the discharge pump. The steam outlet is located at the top of the separator, the steam inlet is located on the evaporator body, the material inlet is located at the top of the evaporator body, and the material outlet is located at the rear of the outlet of the discharge pump.
9. The multi-effect evaporator according to any one of claims 1-8, characterized in that, It includes nine evaporators connected in series, with the first five of the nine evaporators forming the first group of multi-effect evaporators and the last four forming the second group of multi-effect evaporators.
10. A maltose preparation device, characterized in that, The multi-effect evaporator as described in any one of claims 1-9.