A multi-effect falling film evaporator reflux concentration system

Abstract

The utility model is suitable for starch sugar production and processing technical field, proposes a kind of multi-effect falling-film evaporator reflux concentration system, including the feeding tank of sequential intercommunication, plate heat exchanger, one-effect evaporator, two-effect evaporator, three-effect evaporator, four-effect evaporator, five-effect evaporator, condenser;It further includes the forced reflux pipeline of being arranged on one-effect evaporator, two-effect evaporator, three-effect evaporator, four-effect evaporator, five-effect evaporator, and mass flowmeter is equipped on the discharge pipeline of five-effect evaporator. Above all, the utility model utilizes evaporator forced reflux to increase evaporator heat exchange time, improve heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of starch sugar production and processing technology, and in particular to a multi-effect falling film evaporator reflux concentration system. Background Technology

[0002] In a multi-effect falling film evaporator, the feed liquid is added from the top tube side of the heating chamber and evenly distributed into each heat exchange tube by a liquid distribution and film-forming device. Under the action of gravity and vacuum, it flows uniformly in a film form from top to bottom along the inner wall of the heat exchange tube. During the flow, the heated medium is heated and vaporized, and the generated steam and liquid phase enter the separation chamber of the evaporator together. After thorough separation, the steam enters the heating chamber of the next effect evaporator as the heating medium, completing the evaporation and concentration process of the feed liquid. However, in existing multi-effect falling film evaporators, the contact time between the heating medium entering the heating chamber and the feed liquid in the heat exchange tube is short, resulting in low heat exchange efficiency and energy waste.

[0003] In the production of starch sugars, the sugar solution concentration is very low after decolorization and ion exchange treatment following low-concentration saccharification. Evaporation of water from the sugar solution is then necessary to increase the syrup concentration. Since the temperature of the sugar solution after ion exchange treatment is relatively low, around 55°C, and evaporation and concentration require a large amount of heat, this increases the production cost of starch sugars. Utility Model Content

[0004] In view of this, this utility model proposes a multi-effect falling film evaporator reflux concentration system to solve the problem that starch sugar evaporation requires a large amount of heat, but the short contact time between the heating medium and the liquid in the evaporator and the low heat exchange efficiency lead to increased production costs.

[0005] The technical solution of this utility model is implemented as follows:

[0006] This utility model provides a multi-effect falling film evaporator reflux concentration system, comprising a feed tank, a plate heat exchanger, a first-effect evaporator, a second-effect evaporator, a third-effect evaporator, a fourth-effect evaporator, a fifth-effect evaporator, and a condenser connected in sequence. It also includes forced reflux pipes installed on the first-effect, second-effect, third-effect, fourth-effect, and fifth-effect evaporators, and a mass flow meter installed on the discharge pipe of the fifth-effect evaporator.

[0007] Based on the above technical solutions, preferably, the discharge pipes of the first-effect evaporator, second-effect evaporator, third-effect evaporator, fourth-effect evaporator, and fifth-effect evaporator are all equipped with automatic regulating valves and discharge pumps.

[0008] Based on the above technical solutions, preferably, the inlet of the forced reflux pipe is connected before the automatic regulating valve of the discharge pipe of each evaporator, and the outlet is connected to the top of the heating chamber of each evaporator.

[0009] Based on the above technical solutions, the preferred option is to install an automatic regulating valve on the feed pipe of the single-effect evaporator.

[0010] Based on the above technical solutions, preferably, the forced reflux pipes of the first-effect evaporator, second-effect evaporator, third-effect evaporator, and fourth-effect evaporator are equipped with manual valves, and the forced reflux pipes of the fifth-effect evaporator are equipped with automatic regulating valves.

[0011] Based on the above technical solutions, preferably, the bottom of the separation chamber of the first-effect, second-effect, third-effect, fourth-effect, and fifth-effect evaporators is equipped with a level gauge. The mass flow meter, automatic regulating valve, discharge pump, and level gauge are all connected to the control system.

[0012] Based on the above technical solutions, preferably, an electromagnetic flow meter is also installed on the discharge pipe of the five-effect evaporator.

[0013] The multi-effect falling film evaporator reflux concentration system of this invention has the following advantages over the prior art:

[0014] Increase the feed temperature of the evaporator, control the evaporation flow rate by monitoring the discharge concentration of the five-effect evaporator, adjust the automatic regulating valve of the feed of the first-effect evaporator and the automatic regulating valve of the discharge pipeline of the first to fourth-effect evaporators by adjusting the liquid level of each separation chamber, and use the forced reflux of the evaporator to increase the heat exchange time and improve the heat exchange efficiency, resulting in high utilization of the heating medium and reduced production costs. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is a diagram of the multi-effect falling film evaporator reflux concentration system in this utility model;

[0017] In the diagram: 1. Feed tank; 2. Plate heat exchanger; 3. First-effect evaporator; 4. Second-effect evaporator; 5. Third-effect evaporator; 6. Fourth-effect evaporator; 7. Fifth-effect evaporator; 8. Condenser; 9. Forced reflux pipe; 10. Mass flow meter; 11. Automatic regulating valve; 12. Discharge pump; 13. Manual valve; 14. Electromagnetic flow meter. Detailed Implementation

[0018] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0019] The multi-effect falling film evaporator includes a feed tank 1, a plate heat exchanger 2, a first-effect evaporator 3, a second-effect evaporator 4, a third-effect evaporator 5, a fourth-effect evaporator 6, a fifth-effect evaporator 7, and a condenser 8, connected in sequence. As is known to those skilled in the art, each evaporator includes a heating chamber and a separation chamber.

[0020] In this utility model, the multi-effect falling film evaporator reflux concentration system is equipped with forced reflux pipes 9 on the first-effect evaporator 3, the second-effect evaporator 4, the third-effect evaporator 5, the fourth-effect evaporator 6, and the fifth-effect evaporator 7, and a mass flow meter 10 is installed on the discharge pipe of the fifth-effect evaporator 7.

[0021] The low-temperature liquid in feed tank 1 exchanges heat with the high-temperature liquid after jet liquefaction via plate heat exchanger 2. After heat exchange, the low-temperature liquid in feed tank 1 can reach above 80°C.

[0022] After heat exchange, the evaporated liquid sequentially enters the first-effect evaporator 3, the second-effect evaporator 4, the third-effect evaporator 5, the fourth-effect evaporator 6, and the fifth-effect evaporator 7. In each evaporator, the liquid is refluxed through the forced reflux pipe 9, allowing for secondary evaporation and enabling the liquid to come into secondary contact with the heating medium, thereby increasing the heat exchange time and improving the heat exchange efficiency.

[0023] The steam after passing through the five-effect evaporator 7 enters the condenser 8, and the concentrated liquid enters the post-evaporation tank for storage.

[0024] In this utility model, the discharge pipes of the first-effect evaporator 3, the second-effect evaporator 4, the third-effect evaporator 5, the fourth-effect evaporator 6, and the fifth-effect evaporator 7 are all equipped with an automatic regulating valve 11 and a discharge pump 12; the inlet of the forced reflux pipe 9 is connected before the automatic regulating valve 11 of the discharge pipe of each evaporator, and the outlet is connected to the top of the heating chamber of each evaporator.

[0025] Preferably, an automatic regulating valve 11 is provided on the feed pipe of the single-effect evaporator 3.

[0026] Preferably, the forced reflux pipes 9 of the first-effect evaporator 3, the second-effect evaporator 4, the third-effect evaporator 5, and the fourth-effect evaporator 6 are equipped with manual valves 13, and the forced reflux pipes 9 of the fifth-effect evaporator 7 are equipped with automatic regulating valves 11.

[0027] Preferably, level gauges are installed at the bottom of the separation chambers of the first-effect evaporator 3, second-effect evaporator 4, third-effect evaporator 5, fourth-effect evaporator 6, and fifth-effect evaporator 7. The mass flow meter 10, automatic regulating valve 11, discharge pump 12, and level gauges are all connected to the control system. The level gauges monitor the liquid level in the separation chambers of each evaporator in real time and transmit the data to the control system.

[0028] The mass flow meter 10 monitors the discharge concentration online. By comparing the set standard concentration value with the online detection concentration value, it controls the automatic regulating valve 11 on the discharge pipe of the five-effect evaporator 7. If the online detection concentration is inconsistent with the standard concentration value, the automatic regulating valve 11 on the discharge pipe of the five-effect evaporator 7 will automatically open or close. Then, according to the opening degree of the automatic regulating valve 11, the opening degree of the manual valve 13 on the forced reflux pipe 9 will be adjusted.

[0029] Preferably, the discharge pipe of the five-effect evaporator 7 is also equipped with an electromagnetic flow meter 14 for online monitoring of the discharge flow rate.

[0030] During the work process:

[0031] According to the online detection of syrup concentration by mass flow meter 10, when the online detected concentration is lower than the standard concentration value, the automatic regulating valve 11 on the discharge pipe of the five-effect evaporator 7 closes slightly, while the automatic regulating valve 11 on the forced reflux pipe 9 of the five-effect evaporator 7 opens slightly. The liquid level in the separation chamber of the five-effect evaporator 7 rises. If the level gauge detects that the liquid level exceeds the set value, it transmits the data to the control system. The control system then controls the automatic regulating valve 11 on the discharge pipe of the four-effect evaporator 6 to close slightly, and so on. The automatic regulating valve 11 on the discharge pipe of the three-effect evaporator 5 closes slightly, the automatic regulating valve 11 on the discharge pipe of the two-effect evaporator 4 closes slightly, the automatic regulating valve 11 on the discharge pipe of the one-effect evaporator 3 closes slightly, and the automatic regulating valve 11 on the feed pipe of the one-effect evaporator 3 closes slightly.

[0032] During normal use, the manual valves 13 on the forced reflux pipes 9 of the first-effect evaporator 3, second-effect evaporator 4, third-effect evaporator 5, and fourth-effect evaporator 6 should be adjusted to their maximum opening. When the automatic regulating valves 11 are closed, the discharge flow rate decreases, and the forced reflux flow rate increases. This increases the forced reflux flow rate of the first-effect evaporator 3, second-effect evaporator 4, third-effect evaporator 5, fourth-effect evaporator 6, and fifth-effect evaporator 7, increases the heat exchange time, improves the evaporation and concentration effect, and thus increases the discharge concentration.

[0033] In this process, the electromagnetic flow meter 14 only assists the mass flow meter 10 in monitoring the discharge flow of the entire system, so that the forced return flow reaches the maximum and the heat exchange effect is the best, while ensuring the stable operation of the system.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multi-effect falling film evaporator reflux concentration system, comprising a feed tank (1), a plate heat exchanger (2), a first-effect evaporator (3), a second-effect evaporator (4), a third-effect evaporator (5), a fourth-effect evaporator (6), a fifth-effect evaporator (7), and a condenser (8) connected in sequence; characterized in that: Forced reflux pipes (9) are provided on the first-effect evaporator (3), second-effect evaporator (4), third-effect evaporator (5), fourth-effect evaporator (6), and fifth-effect evaporator (7), and a mass flow meter (10) is provided on the discharge pipe of the fifth-effect evaporator (7).

2. The multi-effect falling film evaporator reflux concentration system as described in claim 1, characterized in that: The discharge pipes of the first-effect evaporator (3), second-effect evaporator (4), third-effect evaporator (5), fourth-effect evaporator (6), and fifth-effect evaporator (7) are all equipped with automatic regulating valves (11) and discharge pumps (12).

3. The multi-effect falling film evaporator reflux concentration system as described in claim 2, characterized in that: The inlet of the forced reflux pipe (9) is connected before the automatic regulating valve (11) of the discharge pipe of each evaporator, and the outlet is connected to the top of the heating chamber of each evaporator.

4. The multi-effect falling film evaporator reflux concentration system as described in claim 1, characterized in that: The feed pipe of the single-effect evaporator (3) is equipped with an automatic regulating valve (11).

5. The multi-effect falling film evaporator reflux concentration system as described in claim 1, characterized in that: The forced reflux pipes (9) of the first-effect evaporator (3), second-effect evaporator (4), third-effect evaporator (5), and fourth-effect evaporator (6) are equipped with manual valves (13), and the forced reflux pipes (9) of the fifth-effect evaporator (7) are equipped with automatic regulating valves (11).

6. The multi-effect falling film evaporator reflux concentration system as described in claim 1, characterized in that: The bottom of the separation chambers of the first-effect evaporator (3), second-effect evaporator (4), third-effect evaporator (5), fourth-effect evaporator (6), and fifth-effect evaporator (7) are all equipped with level gauges.

7. The multi-effect falling film evaporator reflux concentration system as described in claim 1, characterized in that: The discharge pipe of the five-effect evaporator (7) is also equipped with an electromagnetic flow meter (14).

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