Preheating recovery unit for starch liquefaction

Abstract

The invention relates to a preheating recovery unit for starchiness liquefaction, which belongs to the technical field of energy recovery and comprises a first heat exchanger, a second heat exchanger and a third heat exchanger. A liquefier, a maintainer, a flash separator and a buffer which are sequentially connected end to end are arranged at a material output part of the first heat exchanger, and a heat exchange tube input part of the first heat exchanger is connected with a tail gas emission part of the flash separator; the heat exchange tube input part of the second heat exchanger is connected to the heat exchange tube output part of the first heat exchanger, and the material output part of the second heat exchanger is connected to the material input part of the liquefier; the heat exchange tube input part of the third heat exchanger is connected to the heat exchange tube output part of the second heat exchanger, and the material input part of the third heat exchanger is connected to the material output part of the buffer. According to the invention, heat in starch liquefaction is fully recovered and is applied to a material preheating process, so that the waste of heat is reduced, and the use of external heat by materials is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of energy recovery, in particular to a preheating recovery unit for starch liquefaction. Background Art

[0002] The starch liquefaction process generally includes adding amylase to starch milk, adjusting the starch milk to a preset pH value, and then transporting it to the next stage after liquefaction, maintenance, flash evaporation, and cooling.

[0003] For the above technical process, the material temperature after pH adjustment is generally 25-45°C, and the material needs to be heated to above 110°C during the liquefaction process. At the same time, the temperature of about 100°C is also required in the subsequent maintenance, flash evaporation, laminar flow and other sections. Since the temperature required in some sections is relatively high, if there is a lack of recovery of the waste heat in the section, a large amount of heat energy will be wasted. Therefore, the inventors have proposed a preheating recovery unit that can recover the waste heat in the section and use it to preheat the material. Summary of the invention

[0004] The purpose of the present invention is to provide a preheating recovery unit for starch liquefaction, so as to fully recover the heat in starch liquefaction and apply the heat to the process of material preheating, thereby reducing the waste of heat and reducing the use of external heat by the material.

[0005] The present invention provides a preheating recovery unit for starch liquefaction, which adopts the following technical solution: A preheating recovery unit for starch liquefaction, comprising a first heat exchanger, a second heat exchanger and a third heat exchanger; The material output part of the first heat exchanger is provided with a liquefier, a maintainer, a flash separator and a buffer connected in sequence end to end, and the heat exchange pipe input part of the first heat exchanger is connected to the tail gas discharge part of the flash separator; The heat exchange tube input part of the second heat exchanger is connected to the heat exchange tube output part of the first heat exchanger, and the material output part of the second heat exchanger is connected to the material input part of the liquefier; The heat exchange tube input part of the third heat exchanger is connected to the heat exchange tube output part of the second heat exchanger, and the material input part of the third heat exchanger is connected to the material output part of the buffer.

[0006] Preferably, the heat exchange tube output portion of the third heat exchanger is connected to a steam recovery unit.

[0007] Preferably, a circulating fluid is wound around the pipe between the heat exchange pipe output portion of the second heat exchanger and the heat exchange pipe input portion of the third heat exchanger.

[0008] Preferably, an ejector is provided in the pipeline between the heat exchange tube input part of the first heat exchanger and the flash separator; The ejector end of the ejector is connected to the output part of the steam recovery unit.

[0009] Preferably, the material input part of the first heat exchanger and the material input part of the second heat exchanger are connected to the same material source.

[0010] Preferably, a power fan is connected to the pipeline between the heat exchange tube output part of the first heat exchanger and the heat exchange tube input part of the second heat exchanger.

[0011] Preferably, the first heat exchanger, the second heat exchanger and the third heat exchanger are shell and tube heat exchangers.

[0012] Preferably, the circulating fluid is condensed water.

[0013] In summary, the present invention includes the following beneficial technical effects: 1. In the starch liquefaction process of the present application, the flash temperature of the flash separator is generally about 100-102°C, and the high-temperature tail gas of the flash separator is transported to the first heat exchanger through the tail gas discharge part of the flash separator to heat the material in the first heat exchanger. The temperature at the material input part of the first heat exchanger is generally 35-45°C, and the material input from the first heat exchanger to the liquefier reaches above 95°C after heat exchange, and the liquefier needs to heat the material to 110-112°C, thereby reducing the input of steam; The tail gas discharged from the flash separator still has temperature after passing through the first heat exchanger, and then heats the material in the second heat exchanger to fully utilize the temperature of the tail gas from the flash separator; The flash separator tail gas after passing through the second heat exchanger enters the third heat exchanger. At this time, the temperature of the flash separator tail gas in the third heat exchanger is lower than the temperature of the buffer, thereby cooling the material from the buffer entering the third heat exchanger to enter the next process section.

[0014] 2. The present application accelerates the speed at which the exhaust gas discharged from the flash separator enters the first heat exchanger by setting an ejector, thereby reducing the heat loss during the transmission process. The ejector end of the ejector is connected to the output part of the steam recovery unit. Since the exhaust gas temperature of the flash separator in the steam recovery unit is higher than the outdoor ambient air temperature, the impact on the exhaust gas temperature of the flash separator in the ejector is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a preheating recovery unit for starch liquefaction provided by an embodiment of the present invention.

[0016] Explanation of the reference numerals: 1. first heat exchanger; 11. ejector; 12. power fan; 2. second heat exchanger; 3. third heat exchanger; 4. liquefier; 5. maintainer; 6. flash separator; 7. buffer; 8. circulating fluid; 9. steam recovery unit. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1 The present invention is described in further detail.

[0018] The present invention provides a preheating recovery unit for starch liquefaction, referring to Figure 1 , including a first heat exchanger 1, a second heat exchanger 2 and a third heat exchanger 3. In this embodiment, the first heat exchanger 1, the second heat exchanger 2 and the third heat exchanger 3 are preferably shell and tube heat exchangers; the material input ends of the first heat exchanger 1 and the second heat exchanger 2 are connected to the same material source, that is, the materials are transported to the first heat exchanger 1 and the second heat exchanger 2 at the same time, and the material output parts of the first heat exchanger 1 and the second heat exchanger 2 are connected to the same liquefier 4, and the material output part of the liquefier 4 is provided with a maintainer 5, a flash separator 6 and a buffer 7 (in an actual working environment, a laminar flow tank group is also provided between the flash separator 6 and the buffer 7, and the laminar flow tank group is not shown in this figure), that is, the liquefier 4, the maintainer 5, the flash separator 6 and the buffer 7 are connected end to end along the flow direction of the material; the third heat exchanger 3 is used to recover the steam output by the second heat exchanger 2.

[0019] Reference Figure 1 The heat exchange pipe input part of the first heat exchanger 1 is connected to the tail gas discharge part of the flash separator 6 to heat the material in the first heat exchanger 1. Since the flash temperature of the flash separator 6 is generally 100-102°C, the high-temperature tail gas is transported to the first heat exchanger 1 to heat the material in the first heat exchanger 1. Since the temperature required by the liquefier 4 is generally 110-112°C, the heat-exchanged material is transported to the liquefier 4, which greatly reduces the steam demand of the liquefier 4.

[0020] Reference Figure 1 The heat exchange pipe input part of the second heat exchanger 2 is connected to the heat exchange pipe output part of the first heat exchanger 1, that is, the tail gas passing through the flash separator 6 of the first heat exchanger 1 enters the second heat exchanger 2, and the tail gas still has temperature after passing through the first heat exchanger 1, so that the material in the second heat exchanger 2 can be heated to increase the material temperature of the material input part of the liquefier 4.

[0021] Reference Figure 1, the heat exchange tube input of the third heat exchanger 3 is connected to the heat exchange tube output of the second heat exchanger 2, the material input of the third heat exchanger 3 is connected to the material output of the buffer 7, and the temperature of the tail gas of the flash separator 6 in the third heat exchanger 3 is lower than the temperature of the buffer 7, so that the material entering the third heat exchanger 3 from the buffer 7 can be cooled down, so that the material can enter the next stage. The pipeline between the heat exchange tube output of the second heat exchanger 2 and the heat exchange tube input of the third heat exchanger 3 is wound with a circulating fluid 8. The circulating fluid 8 in this embodiment is preferably condensed water, so as to cool down the tail gas of the flash separator 6 transported from the second heat exchanger 2 to the third heat exchanger 3, so as to accelerate the cooling speed of the third heat exchanger 3 for the input material of the buffer 7.

[0022] Reference Figure 1 , the heat exchange tube output of the third heat exchanger 3 is connected to a steam recovery unit 9 for recovering the steam from the heat exchange tube output of the third heat exchanger 3. The pipeline between the heat exchange tube input of the first heat exchanger 1 and the flash separator 6 is connected to an ejector 11. The ejector 11 in this embodiment is an existing device, which is a power source device that uses a high-speed and high-energy flow to eject another low-speed and low-energy flow. The ejector end of the ejector 11 is connected to the output of the steam recovery unit 9. Since the tail gas temperature of the flash separator 6 in the steam recovery unit 9 is greater than the outdoor ambient air temperature, the connection mode of the ejector end connecting to the air source is replaced by the connection mode of the ejector end connecting to the steam recovery unit 9, thereby reducing the influence of the ejector source on the tail gas temperature of the flash separator 6 in the ejector 11. At the same time, in order to speed up the transmission speed of the tail gas of the flash separator 6 between the first heat exchanger 1 and the second heat exchanger 2, a power fan 12 is connected to the pipeline between the heat exchange tube output of the first heat exchanger 1 and the heat exchange tube input of the second heat exchanger 2.

[0023] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preheating recovery unit for starch liquefaction, characterized in that: It comprises a first heat exchanger (1), a second heat exchanger (2) and a third heat exchanger (3); The material output portion of the first heat exchanger (1) is provided with a liquefier (4), a maintainer (5), a flash separator (6) and a buffer (7) which are connected end to end in sequence, and the heat exchange pipe input portion of the first heat exchanger (1) is connected to the tail gas discharge portion of the flash separator (6); The heat exchange pipe input part of the second heat exchanger (2) is connected to the heat exchange pipe output part of the first heat exchanger (1), and the material output part of the second heat exchanger (2) is connected to the material input part of the liquefier (4); The heat exchange tube input part of the third heat exchanger (3) is connected to the heat exchange tube output part of the second heat exchanger (2), and the material input part of the third heat exchanger (3) is connected to the material output part of the buffer (7).

2. A preheating recovery unit for starch liquefaction according to claim 1, characterized in that: The heat exchange pipe output portion of the third heat exchanger (3) is connected to a steam recovery unit (9).

3. A preheating recovery unit for starch liquefaction according to claim 2, characterized in that: A circulating fluid (8) is provided in the pipeline between the heat exchange tube output portion of the second heat exchanger (2) and the heat exchange tube input portion of the third heat exchanger (3).

4. A preheating recovery unit for starch liquefaction according to claim 2, characterized in that: The pipeline between the heat exchange pipe input part of the first heat exchanger (1) and the flash separator (6) is provided with an ejector (11); The ejector end of the ejector (11) is connected to the output portion of the steam recovery unit (9).

5. The preheating recovery unit for starch liquefaction according to claim 1, characterized in that: The material input part of the first heat exchanger (1) and the material input part of the second heat exchanger (2) are connected to the same material source.

6. A preheating recovery unit for starch liquefaction according to claim 1, characterized in that: The pipeline between the heat exchange tube output portion of the first heat exchanger (1) and the heat exchange tube input portion of the second heat exchanger (2) is connected to a power fan (12).

7. The preheating recovery unit for starch liquefaction according to claim 1, characterized in that: The first heat exchanger (1), the second heat exchanger (2) and the third heat exchanger (3) are shell and tube heat exchangers.

8. The preheating recovery unit for starch liquefaction according to claim 3, characterized in that: The circulating fluid (8) is condensed water.

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