Improved evaporative crystallization treatment system

Abstract

The utility model relates to the field of hazardous waste treatment equipment, in particular to an improved evaporative crystallization treatment system, which comprises a multi-effect evaporation unit, a stock solution supply unit, a solid-liquid separation unit and a cleaning unit, the stock solution supply unit is communicated with a liquid inlet of a first-effect evaporation device of the multi-effect evaporation unit through a liquid conveying pipeline, a heat exchanger is arranged on the liquid conveying pipeline, and a steam output port of a last-effect evaporation device of the multi-effect evaporation unit is connected to an input port of a heat conduction pipe of the heat exchanger through a steam conveying pipeline. The cleaning unit is provided with a cleaning liquid conveying pipe, a cleaning liquid conveying pump and a cleaning liquid output pipe and is connected to the multi-effect evaporation unit through a second adapter valve and a first adapter valve, and a heat exchanger is utilized to enable steam waste heat discharged by a last-effect evaporation device to preheat stock solution provided by the stock solution supply unit; the cleaning unit is used for washing the interior of the multi-effect evaporation unit, so that energy can be saved, and the treatment efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of hazardous waste treatment equipment, and particularly relates to an improved evaporation crystallization treatment system. BACKGROUND

[0002] After pretreatment, industrial wastewater, especially high-salinity wastewater, is often treated by evaporation crystallization to evaporate and separate the solvent in the mother liquor, and the solid matter after crystallization is recycled. Considering that a large amount of heat energy is required for evaporation crystallization, the mother liquor is usually treated by a multi-effect, such as a two-effect, three-effect or four-effect evaporation device, to repeatedly heat and evaporate the solution, and then a centrifuge is used to centrifugally treat the concentrated liquid after evaporation to separate the solid matter. However, the terminal steam after multi-effect evaporation still contains some heat energy. To avoid the impact on the surrounding environment caused by unorganized discharge, the terminal steam is generally condensed to form condensed water, which is then discharged or collected. Although this method does not affect the environment, the heat energy of the terminal steam is not further collected and utilized, resulting in resource waste. In addition, a cold source needs to be constantly provided during condensation, which increases the processing cost and resource consumption. Furthermore, the high-salinity mother liquor is prone to scaling in the multi-effect evaporation device during treatment. Although there is a disclosed technology of adding a forced circulation pump between each heating chamber and evaporation chamber to increase the flow rate of the mother liquor and slow down the scaling rate, the internal mother liquor will naturally crystallize or precipitate to form dirt when the device is not in use, which affects the processing efficiency of the evaporation crystallization treatment system. Therefore, if the evaporation crystallization treatment system can be improved to provide heat energy to the raw liquid by heat exchange using the residual heat in the terminal steam, the resource utilization can be further improved and the energy consumption can be reduced. If the multi-effect evaporation device is additionally provided with a forced cleaning function to reduce internal precipitation and scaling, the energy consumption can be saved and the processing efficiency can be improved. SUMMARY

[0003] The utility model discloses an improved evaporation crystallization treatment system, including multi -effect evaporation unit, raw liquid supply unit, solid -liquid separation unit and cleaning unit, the multi -effect evaporation unit contains from front to back and is arranged in proper order several effect evaporation device and is communicated by liquid conveying pipeline and vapor conveying pipeline between adjacent evaporation device, raw liquid supply unit is communicated with the liquid inlet of the first effect evaporation device of multi -effect evaporation unit with liquid conveying pipeline, is equipped with the heat exchanger of heat pipe on this liquid conveying pipeline, the steam output of the last effect evaporation device of multi -effect evaporation unit is connected to the input of the heat pipe of heat exchanger with vapor conveying pipeline, and cleaning unit is equipped with cleaning liquid delivery pipe and cleaning liquid delivery pump and is connected to the liquid inlet of the first effect evaporation device of multi -effect evaporation unit with second switching valve, and cleaning unit is also equipped with cleaning liquid output pipe and is connected to the liquid outlet of the last effect evaporation device of multi -effect evaporation unit with first switching valve.

[0004] To achieve the above object, the technical scheme adopted by the utility model is as follows:

[0005] An improved evaporation crystallization treatment system, including multi -effect evaporation unit, the multi -effect evaporation unit contains from front to back and is arranged in proper order several effect evaporation device and is communicated by liquid conveying pipeline and vapor conveying pipeline that can transport liquid between adjacent evaporation device, it is characterized by: still including raw liquid supply unit and cleaning unit, the liquid inlet of the first effect evaporation device of multi -effect evaporation unit is communicated with raw liquid supply unit with liquid conveying pipeline, is equipped with the heat exchange component of heat pipe on the liquid conveying pipeline of raw liquid supply unit, the steam output of the last effect evaporation device of multi -effect evaporation unit is connected on the input of the heat pipe of heat exchange component on the liquid conveying pipeline of raw liquid supply unit, and the steam waste heat of the last effect evaporation device of multi -effect evaporation unit can preheat the raw liquid transported in the liquid conveying pipeline of raw liquid supply unit, the cleaning unit is equipped with two liquid conveying pipelines and is communicated with the liquid inlet of the first effect evaporation device and the liquid outlet of the last effect evaporation device of multi -effect evaporation unit respectively, and cleaning unit can transport cleaning water liquid to the inside of multi -effect evaporation unit and flush the inside of multi -effect evaporation unit and can recover the residual liquid after flushing.

[0006] The multi-effect evaporation unit comprises a first effect evaporation group, a second effect evaporation group and a third effect evaporation group connected in sequence from front to back, each of the first effect evaporation group, the second effect evaporation group and the third effect evaporation group comprises a heating chamber and an evaporation chamber communicated with the heating chamber, the steam output port of the evaporation chamber of the former effect in the two adjacent effect evaporation groups is communicated with the steam input port of the heating chamber of the latter effect by a steam pipeline, the mother liquor output port of the evaporation chamber of the former effect is communicated with the mother liquor input port of the evaporation chamber of the latter effect by a liquid pipeline, a mother liquor backflow pipe is arranged between the evaporation chamber and the heating chamber of each of the first effect evaporation group, the second effect evaporation group and the third effect evaporation group, and a forced circulation pump is arranged on the mother liquor backflow pipe, the steam input port of the first effect evaporation group is provided with a live steam input pipe, the liquid inlet of the heating chamber of the first effect evaporation group is provided with a liquid inlet pipe, the steam output port of the third effect evaporation group is provided with a terminal steam delivery pipe, and the condensate water output ports of the first effect evaporation group, the second effect evaporation group and the third effect evaporation group are all connected to a condensate water delivery pipe arranged on the multi-effect evaporation unit.

[0007] The multi-effect evaporation unit further comprises a first switching valve, which is a switching member provided with two outlets and one inlet and capable of making any one of the outlets communicated with the inlet and the other outlet closed by rotating the valve core, the two outlets are respectively set as f port and g port, and the inlet is set as e port, and the e port of the first switching valve is connected to the liquid outlet of the third effect evaporation group.

[0008] The raw liquid supply unit comprises a raw liquid storage pool, a raw liquid delivery pump, a heat exchanger and a condensate water collection pool, the raw liquid storage pool is externally provided with a raw liquid delivery pipe communicated with the raw liquid storage pool, the raw liquid delivery pump and the heat exchanger are both connected to the raw liquid delivery pipe, the heat exchanger is a tubular cavity body provided with a spiral heat conduction pipe on the inner wall thereof, both ends of the heat conduction pipe are communicated with the raw liquid delivery pipe, the input port of the heat conduction pipe is connected to the terminal steam delivery pipe, the output port of the heat conduction pipe is provided with a residual steam and water output pipe, and the residual steam and water output pipe extends into the condensate water collection pool, and the condensate water delivery pipe of the multi-effect evaporation unit extends into the condensate water collection pool.

[0009] The raw liquid supply unit further comprises a second switching valve, which is a switching member provided with two inlets and one outlet and capable of making any one of the inlets communicated with the outlet and the other inlet closed by rotating the valve core, the two inlets are respectively set as b port and c port, and the inlet is set as a port, the raw liquid delivery pipe is connected to the b port, and the a port of the second switching valve is connected to the liquid inlet pipe.

[0010] The cleaning unit comprises a cleaning liquid supply pool, a cleaning liquid recovery pool and a cleaning liquid delivery pump, the cleaning liquid supply pool is provided with a cleaning liquid delivery pipe above, one end of the cleaning liquid delivery pipe extends into the cleaning liquid supply pool, the other end of the cleaning liquid delivery pipe is connected with the c port of the second adapter valve, the cleaning liquid delivery pump is connected with the cleaning liquid delivery pipe, the cleaning liquid recovery pool is provided with a cleaning liquid output pipe above, one end of the cleaning liquid output pipe extends into the cleaning liquid recovery pool, the other end of the cleaning liquid output pipe is connected with the g port of the first adapter valve.

[0011] The improved evaporation crystallization treatment system further comprises a solid-liquid separation unit, the solid-liquid separation unit comprises a cyclone thickener, a centrifuge, a concentrated liquid delivery pump, a clear liquid return pump, a solid collection pool and a separation liquid collection pool, the solid collection pool and the separation liquid collection pool are arranged side by side, the cyclone thickener, the centrifuge and the solid collection pool are sequentially arranged from top to bottom, the cyclone thickener is provided with a concentrated liquid input port, a cycloned clear liquid output port and a thickened material output port, a concentrated liquid delivery pipe is connected with the concentrated liquid input port of the cyclone thickener, the other end of the concentrated liquid delivery pipe is connected with the f port of the first adapter valve, the concentrated liquid delivery pump is connected with the concentrated liquid delivery pipe, a clear liquid return pipe is connected with the clear liquid output port of the cyclone thickener, the other end of the clear liquid return pipe is connected with a clear liquid receiving port arranged in the third evaporation group, the thickened material output port of the cyclone thickener is connected with the input port of the centrifuge, the solid output port and the separation liquid output port of the centrifuge are respectively connected with the solid collection pool and the separation liquid collection pool.

[0012] All liquid delivery pipes and steam delivery pipes for delivering liquid and steam in the improved evaporation crystallization treatment system are provided with check valves.

[0013] From the above description, the improved evaporation crystallization treatment system has the advantages that: first, a heat exchanger with a heat conducting pipe is arranged on the liquid conveying pipeline of the raw liquid supply unit, and the steam output port of the last-effect evaporation device of the multi-effect evaporation unit is connected to the input port of the heat conducting pipe of the heat exchanger through a steam conveying pipeline, so that the waste heat of the steam discharged by the last-effect evaporation device is used to preheat the raw liquid conveyed in the liquid conveying pipeline of the raw liquid supply unit, thereby further utilizing the waste heat and reducing energy consumption; second, the second switching valve and the first switching valve are arranged on the liquid inlet and the liquid outlet of the first-effect and last-effect evaporation devices of the multi-effect evaporation unit respectively, and the cleaning liquid conveying pipeline and the cleaning liquid output pipeline of the cleaning unit are connected to the two switching valves respectively, so that the cleaning liquid conveying pipeline, the cleaning liquid conveying pump, the cleaning liquid output pipeline and the two switching valves connected thereto are switched to flush the inside of the multi-effect evaporation unit and recycle the residual liquid after flushing to reduce internal precipitation and scaling, and the heating and evaporation efficiency is higher.

[0014] The utility model discloses the design is reasonable, simple structure, low in cost, and convenient to promote. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is the working principle diagram of an improved evaporation crystallization treatment system of the utility model;

[0016] Figure 2 It is the working principle diagram of a multi-effect evaporation unit;

[0017] Figure 3 It is the working principle diagram of a raw liquid supply unit;

[0018] Figure 4 It is the enlarged schematic diagram of a heat exchanger;

[0019] Figure 5 It is the working principle diagram of a solid-liquid separation unit;

[0020] Figure 6 It is the working principle diagram of a cleaning unit.

[0021] REFERENCE NUMERALS:

[0022] 1. Multi-effect evaporation unit; 11. I-effect evaporation group; 12. II-effect evaporation group; 13. III-effect evaporation group; 14. Forced circulation pump; 15. First transfer valve; 2. Raw liquid supply unit; 21. Raw liquid storage tank; 22. Raw liquid delivery pump; 23. Heat exchanger; 24. Second transfer valve; 25. Condensate collection tank; 3. Solid-liquid separation unit; 31. Cyclone thickener; 32. Centrifuge; 33. Concentrate delivery pump; 34. Clear liquid return pump; 35. Solid matter collection tank; 36. Separated liquid collection tank; 4. Cleaning unit; 41. Cleaning liquid supply tank; 42. Cleaning liquid recovery tank; 43. Cleaning liquid delivery pump; L1. Liquid inlet pipe; L2. Raw liquid delivery pipe; L3. Concentrate delivery pipe; S1. Raw steam inlet pipe; S2. Terminal steam delivery pipe; S3. Residual steam-water output pipe; W1. Condensate delivery pipe; W2. Clear liquid reflux pipe; R1. Cleaning liquid delivery pipe; R2. Cleaning liquid output pipe. DETAILED DESCRIPTION

[0023] The present invention is further described below through specific implementation methods.

[0024] like Figure 1 As shown, the improved evaporation crystallization processing system described in the present invention includes a multi-effect evaporation unit 1, a raw liquid supply unit 2, a solid-liquid separation unit 3 and a cleaning unit 4. The multi-effect evaporation unit 1 includes a plurality of effect evaporation devices arranged in sequence from front to back, and adjacent evaporation devices are connected by a liquid delivery pipeline that can deliver liquid and a steam delivery pipeline that can deliver steam. The raw liquid supply unit 2 is connected to the liquid inlet of the first effect evaporation device of the multi-effect evaporation unit 1 by a liquid delivery pipeline. A heat exchange component with a heat conduction pipe is provided on the liquid delivery pipeline of the raw liquid supply unit 2. The multi-effect evaporation unit The steam output port of the last-effect evaporation device of the multi-effect evaporation unit 1 is connected to the input port of the heat conduction pipe of the heat exchange component on the liquid infusion pipeline of the raw liquid supply unit 2. The waste heat of the steam discharged from the last-effect evaporation device of the multi-effect evaporation unit 1 can preheat the raw liquid transported in the liquid infusion pipeline of the raw liquid supply unit 2. The cleaning unit 4 is provided with two liquid infusion pipelines and is respectively connected to the liquid inlet of the first-effect evaporation device and the liquid outlet of the last-effect evaporation device of the multi-effect evaporation unit 1. The cleaning unit 4 can transport cleaning water into the interior of the multi-effect evaporation unit 1 to flush the interior of the multi-effect evaporation unit 1 and can recover the residual liquid after flushing.

[0025] like Figure 1 and Figure 2As shown in the utility model discloses the multiple effect evaporation unit 1 contains from front to rear and connects the first I effect evaporation group 11, the second effect evaporation group 12, the third effect evaporation group 13, the first I effect evaporation group 11, the second effect evaporation group 12 and the third effect evaporation group 13 each contain heating chamber and with heating chamber intercommunication's evaporation chamber, the evaporation chamber's steam output of the preceding effect in adjacent two effect evaporation groups with the steam input of the heating chamber of the following effect is communicated with steam pipeline, the mother liquor output of the preceding effect's evaporation chamber with the mother liquor input of the evaporation chamber of the following effect is communicated with liquid pipeline, the evaporation chamber of the first I effect evaporation group 11, the second effect evaporation group 12 and the third effect evaporation group 13 each's heating chamber between the evaporation chamber is equipped with mother liquor backflow pipe and is equipped with forced circulation pump 14 on mother liquor backflow pipe, the steam input of the first I effect evaporation group 11 is equipped with live steam input pipe S1, and the inlet of the heating chamber of the first I effect evaporation group 11 is equipped with liquid inlet pipe L1, the steam output on the third effect evaporation group 13 is equipped with terminal steam delivery pipe S2, the condensate water output of the first I effect evaporation group 11, the second effect evaporation group 12 and the third effect evaporation group 13 are all connected on the condensate water delivery pipe W1 that multiple effect evaporation unit 1 is provided with.

[0026] As Figures 1 to 4 shown, the utility model discloses the raw liquid supply unit 2 includes raw liquid storage pool 21, raw liquid delivery pump 22, heat exchanger 23 and condensate collection pool 25, the raw liquid storage pool 21 outside be provided with with raw liquid storage pool 21 intercommunication's raw liquid delivery pipe L2, raw liquid delivery pump 22 and heat exchanger 23 all are connected on raw liquid delivery pipe L2, the heat exchanger 23 be the tubular cavity body that is equipped with spiral heat conduction pipe on its inner wall, both ends all with raw liquid delivery pipe L2 intercommunication, its heat conduction pipe's input and terminal steam delivery pipe S2 are connected, and heat conduction pipe's output is equipped with residual steam water output pipe S3, and residual steam water output pipe S3 extends to condensate collection pool 25, and the condensate water delivery pipe W1 of multiple effect evaporation unit 1 extends to condensate collection pool 25. The raw liquid supply unit 2 still includes second adapter valve 24, and the second adapter valve 24 is equipped with two inlets and an outlet and can make any one inlet and the outlet intercommunication while the other inlet is closed by the rotation of the valve core, and two inlets are respectively equipped as b mouth and c mouth, and one inlet is equipped as a mouth, the raw liquid delivery pipe L2 is connected on b mouth, and the a mouth of second adapter valve 24 is connected with liquid inlet pipe L1.

[0027] As Figures 1 to 3 ,Figure 6 As shown in the washing unit 4, the utility model discloses a cleaning liquid supply pool 41, cleaning liquid recovery pool 42 and cleaning liquid delivery pump 43, the upper of cleaning liquid supply pool 41 is equipped with cleaning liquid delivery pipe R1, one end of cleaning liquid delivery pipe R1 extends to cleaning liquid supply pool 41, the other end of cleaning liquid delivery pipe R1 is connected with the c mouth of second adapter valve 24, cleaning liquid delivery pump 43 is connected on cleaning liquid delivery pipe R1, the upper of cleaning liquid recovery pool 42 is equipped with cleaning liquid output pipe R2, one end of cleaning liquid output pipe R2 extends to cleaning liquid recovery pool 42, the other end of cleaning liquid output pipe R2 is connected with the g mouth of first adapter valve 15.

[0028] As shown in the washing unit 4, the utility model discloses a cleaning liquid supply pool 41, cleaning liquid recovery pool 42 and cleaning liquid delivery pump 43, the upper of cleaning liquid supply pool 41 is equipped with cleaning liquid delivery pipe R1, one end of cleaning liquid delivery pipe R1 extends to cleaning liquid supply pool 41, the other end of cleaning liquid delivery pipe R1 is connected with the c mouth of second adapter valve 24, cleaning liquid delivery pump 43 is connected on cleaning liquid delivery pipe R1, the upper of cleaning liquid recovery pool 42 is equipped with cleaning liquid output pipe R2, one end of cleaning liquid output pipe R2 extends to cleaning liquid recovery pool 42, the other end of cleaning liquid output pipe R2 is connected with the g mouth of first adapter valve 15. Figure 1 、 Figure 2 and Figure 5 As shown in the washing unit 4, the utility model discloses a cleaning liquid supply pool 41, cleaning liquid recovery pool 42 and cleaning liquid delivery pump 43, the upper of cleaning liquid supply pool 41 is equipped with cleaning liquid delivery pipe R1, one end of cleaning liquid delivery pipe R1 extends to cleaning liquid supply pool 41, the other end of cleaning liquid delivery pipe R1 is connected with the c mouth of second adapter valve 24, cleaning liquid delivery pump 43 is connected on cleaning liquid delivery pipe R1, the upper of cleaning liquid recovery pool 42 is equipped with cleaning liquid output pipe R2, one end of cleaning liquid output pipe R2 extends to cleaning liquid recovery pool 42, the other end of cleaning liquid output pipe R2 is connected with the g mouth of first adapter valve 15.

[0029] All the liquid delivery pipes and steam delivery pipes for delivering liquid and steam in the present evaporation crystallization treatment system are provided with check valves for limiting the reverse flow of liquid or steam, and the check valves are not shown in the drawings.

[0030] When the evaporation crystallization treatment system is used, the valve core of the second switching valve 24 and the first switching valve 15 is driven to rotate, and the b port is communicated with the a port, and the e port is communicated with the f port. Then the raw liquid conveying pump 22 of the raw liquid supply unit 2 is started to send the wastewater raw liquid to be treated into the multi-effect evaporation unit 1, and the live steam is sent into the multi-effect evaporation unit 1 from the live steam input pipe S1 to carry out multi-effect heating and evaporation, and the steam discharged from the terminal of the multi-effect evaporation unit 1 is sent into the heat conduction pipe of the heat exchanger 23 from the terminal steam conveying pipe S2 to preheat the raw liquid flowing in the raw liquid conveying pipe L2, so that the raw liquid is in a hot state before being sent into the multi-effect evaporation unit 1, thereby reducing the consumption of live steam when the multi-effect evaporation unit 1 works. After the terminal steam transmits heat energy to the raw liquid through the heat exchanger 23, the temperature of the terminal steam is reduced, and the terminal steam can be collected or discharged without cooling, thereby saving the consumption of cold source.

[0031] If the evaporation crystallization treatment system needs to be suspended or stopped for maintenance, after the system is stopped, the valve core of the second switching valve 24 and the first switching valve 15 is driven to rotate, and the c port is communicated with the a port, and the e port is communicated with the g port. Then the cleaning liquid conveying pump 43 of the cleaning unit 4 is started to send the water liquid containing cleaning agent into the multi-effect evaporation unit 1 to carry out high-pressure flushing, and the forced circulation pump 14 can be started to carry out circulation flushing, and if necessary, the live steam can be sent into the multi-effect evaporation unit 1 from the live steam input pipe S1 to heat the water liquid containing cleaning agent to enhance the flushing effect, and the residual liquid after flushing is discharged from the cleaning liquid output pipe R2 for recovery.

[0032] The evaporation crystallization treatment system is improved, the heat exchanger 23 with a heat conduction pipe is arranged on the liquid conveying pipeline of the raw liquid supply unit 2, the steam output port of the last-effect evaporation device of the multi-effect evaporation unit 1 is connected to the input port of the heat conduction pipe of the heat exchanger 23 through a steam conveying pipeline, the heat exchanger 23 with a heat conduction pipe is used to preheat the raw liquid conveyed in the liquid conveying pipeline of the raw liquid supply unit 2 by the steam waste heat discharged from the last-effect evaporation device, so that the waste heat is further utilized and the energy consumption is reduced, the second switching valve 24 and the first switching valve 15 are arranged on the liquid inlet and the liquid outlet of the first-effect and last-effect evaporation devices of the multi-effect evaporation unit 1, the cleaning liquid conveying pipe R1 and the cleaning liquid output pipe R2 of the cleaning unit 4 are connected to the two switching valves respectively, the cleaning liquid conveying pipe R1, the cleaning liquid conveying pump 43, the cleaning liquid output pipe R2 and the two switching valves connected thereto of the cleaning unit 4 are used for cooperation and switching, so that the inside of the multi-effect evaporation unit 1 can be flushed and the residual liquid after flushing can be recovered to reduce internal deposition and scaling, thereby saving energy and improving treatment efficiency.

[0033] The above is only one specific embodiment of the utility model, but the design concept of the utility model is not limited to this, and any non-substantial change of the utility model by using the concept should belong to the behavior of infringing the protection range of the utility model.

Claims

1. An improved evaporative crystallization process system comprising a multiple effect evaporation unit (1) comprising a plurality of effect evaporation devices arranged in series from front to back and connected by liquid transfer conduits and vapor transfer conduits between adjacent effect evaporation devices, characterized in that: The application also comprises a raw liquid supply unit (2) and a cleaning unit (4), the raw liquid supply unit (2) is communicated with the liquid inlet of the first effect evaporation device of the multi-effect evaporation unit (1) through a liquid conveying pipeline, a heat exchange component with a heat conducting pipe is arranged on the liquid conveying pipeline of the raw liquid supply unit (2), the steam output port of the last effect evaporation device of the multi-effect evaporation unit (1) is connected to the input port of the heat conducting pipe of the heat exchange component on the liquid conveying pipeline of the raw liquid supply unit (2), the steam waste heat discharged by the last effect evaporation device of the multi-effect evaporation unit (1) can preheat the raw liquid conveyed in the liquid conveying pipeline of the raw liquid supply unit (2), the cleaning unit (4) is provided with two liquid conveying pipelines and is respectively communicated with the liquid inlet of the first effect evaporation device and the liquid outlet of the last effect evaporation device of the multi-effect evaporation unit (1), the cleaning unit (4) can convey cleaning water to the inside of the multi-effect evaporation unit (1) to flush the inside of the multi-effect evaporation unit (1) and can recycle the residual liquid after flushing.

2. An improved evaporative crystallization process system as claimed in claim 1, wherein: The multi-effect evaporation unit (1) comprises a first effect evaporation group (11), a second effect evaporation group (12) and a third effect evaporation group (13) connected in sequence from front to back, the first effect evaporation group (11), the second effect evaporation group (12) and the third effect evaporation group (13) each comprise a heating chamber and an evaporation chamber communicated with the heating chamber, the steam input port of the first effect evaporation group (11) is provided with a live steam input pipe (S1), the liquid inlet of the heating chamber of the first effect evaporation group (11) is provided with a liquid inlet pipe (L1), the steam output port of the third effect evaporation group (13) is provided with a terminal steam conveying pipe (S2), and the condensate water outlets of the first effect evaporation group (11), the second effect evaporation group (12) and the third effect evaporation group (13) are all connected to a condensate water conveying pipe (W1) arranged on the multi-effect evaporation unit (1).

3. An improved evaporative crystallization process system as claimed in claim 2, wherein: The multi-effect evaporation unit (1) further comprises a first switching valve (15), the first switching valve (15) is a switching component provided with two outlets and one inlet and can make any one of the outlets communicated with the inlet and the other outlet closed by rotating a valve core, and the inlet of the first switching valve (15) is connected to the liquid outlet of the third effect evaporation group (13).

4. An improved evaporative crystallization process system as claimed in claim 3, wherein: The raw liquid supply unit (2) comprises a raw liquid storage pool (21), a raw liquid conveying pump (22), a heat exchanger (23) and a condensate water collecting pool (25), the raw liquid storage pool (21) is externally provided with a raw liquid conveying pipe (L2) communicated with the raw liquid storage pool (21), the raw liquid conveying pump (22) and the heat exchanger (23) are both connected to the raw liquid conveying pipe (L2), the heat exchanger (23) is a tubular cavity body provided with a spiral heat conducting pipe on the inner wall thereof, both ends of the heat exchanger (23) are communicated with the raw liquid conveying pipe (L2), the input port of the heat conducting pipe is connected to the terminal steam conveying pipe (S2), the output port of the heat conducting pipe is provided with a residual steam and water output pipe (S3), the residual steam and water output pipe (S3) extends into the condensate water collecting pool (25), and the condensate water conveying pipe (W1) of the multi-effect evaporation unit (1) extends into the condensate water collecting pool (25).

5. An improved evaporative crystallization process system as claimed in claim 4, wherein: The raw solution supply unit (2) further comprises a second switching valve (24), which is a switching member provided with two inlets and one outlet and capable of connecting any one of the inlets with the outlet and closing the other inlet by rotating a valve core, the raw solution delivery pipe (L2) is connected to one of the inlets, and the inlet of the second switching valve (24) is connected with the liquid inlet pipe (L1).

6. An improved evaporative crystallization process system as claimed in claim 5, wherein: The cleaning unit (4) comprises a cleaning solution supply pool (41), a cleaning solution recovery pool (42) and a cleaning solution delivery pump (43), the cleaning solution delivery pipe (R1) is provided above the cleaning solution supply pool (41), one end of the cleaning solution delivery pipe (R1) extends into the cleaning solution supply pool (41), the other end of the cleaning solution delivery pipe (R1) is connected with one inlet of the second switching valve (24), the cleaning solution delivery pump (43) is connected with the cleaning solution delivery pipe (R1), the cleaning solution output pipe (R2) is provided above the cleaning solution recovery pool (42), one end of the cleaning solution output pipe (R2) extends into the cleaning solution recovery pool (42), and the other end of the cleaning solution output pipe (R2) is connected with one outlet of the first switching valve (15).

7. An improved evaporative crystallization process system as claimed in claim 6, wherein: The solid-liquid separation unit (3) further comprises a cyclone thickener (31), a centrifuge (32), a concentrated solution delivery pump (33), a clear liquid return pump (34), a solid matter collection pool (35) and a separation liquid collection pool (36), the solid matter collection pool (35) and the separation liquid collection pool (36) are arranged side by side, the cyclone thickener (31), the centrifuge (32) and the solid matter collection pool (35) are arranged in sequence from top to bottom, the cyclone thickener (31) is provided with a concentrated solution input port, a clear liquid output port after cyclone and a thick substance output port, a concentrated solution delivery pipe (L3) is connected to the concentrated solution input port, the other end of the concentrated solution delivery pipe (L3) is connected with one outlet of the first switching valve (15), the concentrated solution delivery pump (33) is connected with the concentrated solution delivery pipe (L3), a clear liquid return pipe (W2) is connected to the clear liquid output port of the cyclone thickener (31), the other end of the clear liquid return pipe (W2) is connected with a clear liquid receiving port provided in the third evaporation group (13), the thick substance output port of the cyclone thickener (31) is connected with the input port of the centrifuge (32), and the solid matter output port and the separation liquid output port of the centrifuge (32) are connected with the solid matter collection pool (35) and the separation liquid collection pool (36) respectively.

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