Forced circulation continuous crystallization system with mechanical vapor recompression function

[0013] like figure 1 As shown, the forced circulation continuous crystallizer with mechanical vapor recompression includes a crystallizer 1, a compressor 2, a heater 4, a circulation pipe 16 at the bottom of the crystallizer 1, a circulation pump 11 on the circulation pipe 16, and after the circulation pump 11 There is a discharge pipe 17, a discharge pump 10 is arranged behind the discharge pipe 17, a finished product tank 9 is provided at the end of the discharge pipe 17, the top of the crystallizer 1 is connected to the inlet of the compressor 2 through a pipe 27, and the lower part of the heater 4 is provided with a lower part. The upper part of the head 28 is provided with an upper head 29, the bottom of the lower head 28 is connected with the circulation pipe 16, a feed pipe 30 is arranged on one side of the lower head 28, and the feed pipe 30 is provided with a flow meter 13, a ball valve 31 and a feed pump 12. The end of the feed pipe 30 is connected to the raw material tank 14, the upper head 29 is connected to the crystallizer 1 through the pipeline 18, the shell side 33 of the heater 4 is connected to the outlet of the compressor 2 through the pipeline 19, and the shell side 33 of the heater 4 is connected to the outlet of the compressor 2. The bottom is provided with an evacuation pipe 20 and a condensed water discharge pipe 21. The evacuation pipe 20 is provided with a balance pipe 22, a ball valve 5 and a vacuum pump 6. The balance pipe 22 is provided with a ball valve 23. The discharge pipe 21 is provided with a sight pipe 7 and a ball valve 25, the end of the condensate water discharge pipe 21 is connected with the condensation tank 24, the bottom of the condensation tank 24 is provided with an emptying pipe, and the emptying pipe is provided with a ball valve (26) and an emptying pump (8). ).

[0014] The feed liquid in the raw material tank 14 is heated and preheated to the boiling point by the heat exchanger 15 and then continuously enters the heater 4 to be heated and evaporated. After the heated feed liquid is sent to the crystallizer 1 for separation, the concentrated feed liquid falls to the crystallizer 1. The crystal slurry is formed at the bottom of the crystal slurry, and the crystal slurry enters the discharge pipe 17 through the circulating pipe 16 and the circulating pump 11, and the crystal slurry is continuously discharged to the finished product tank 9 through the discharging pump 10, and the other part continues to participate in the circulation. The secondary steam separated in the crystallizer 1 is sent to the compressor 2 through the pipeline 27, and is compressed and heated by the compressor 2, and then sent to the heater tube side to release the latent heat to heat the solution in the heat exchange tube 35. The condensed water is discharged to the condensing tank 24 through the condensing water discharge pipe 21. The lower part of the condensing water pipe is equipped with an emptying pipe. The emptying pipe is provided with a ball valve 26 and an emptying pump 8. Condensate drains. The inlet and outlet of the compressor are connected by a bypass pipe 32, and a ball valve 3 is arranged on the bypass pipe, which can protect the compressor from being overloaded due to excessive load when starting and stopping. In order to make the material liquid evaporate at low temperature, the vacuum degree maintenance of the system and the discharge of non-condensable gas are completed by the vacuum pump 6 on the evacuation pipe 20, and a ball valve 5 is provided on the evacuation pipe before the vacuum pump to control the vacuum degree of the system, A balance pipe 22 connected to the condensing tank is arranged in front of the evacuation pipe ball valve, and a ball valve 23 is arranged on the balance pipe.