CN101874938A - Forced circulation continuous crystallization system with mechanical vapor recompression function - Google Patents

Abstract

The forced circulation continuous crystallization system with mechanical vapor recompression relates to a continuous crystallization system, including a crystallizer, a compressor, and a heater. The bottom of the crystallizer is connected to a circulation pipe, and the other end of the circulation pipe is connected to a circulation pump The feed port of the circulating pump is connected to the discharge pipe, the other end of the discharge pipe is connected to the feed port of the discharge pump, the discharge port of the discharge pump is connected to the finished product tank, and the top of the crystallizer is connected to the The inlet of the compressor is connected, the lower head is connected to the circulation pipe, one side of the lower head is connected to the feed pipe, the feed pipe is equipped with a ball valve and a feed pump, and the other end of the feed pipe is connected to the raw material tank; the upper head is passed through the pipeline It is connected with the crystallizer, and a shell side is arranged outside the heater, and the shell side is connected with the outlet of the compressor through a pipeline, the heater is connected with an evacuation pipeline, and the shell side is connected with a condensed water discharge pipe. The invention can meet the crystallization production requirement of continuous feeding and discharging, adopts a compressor to collect secondary steam, and saves energy.

Description

Forced circulation continuous crystallization system with mechanical vapor recompression

technical field

The invention relates to a continuous crystallization system, in particular to an energy-saving continuous crystallizer, that is, a forced circulation continuous crystallization system with mechanical steam recompression.

Background technique

The traditional crystallization equipment is to first put the solution to be crystallized into the crystallizer, and then run the equipment for a period of time. When the solution is concentrated and concentrated to a certain crystallization amount, turn on the discharge pump to discharge the crystal slurry, and wait for the crystal slurry to be emptied again. Open the feed valve to load the stock solution, repeat the above process. This makes continuous production impossible for production gaps. In addition, traditional crystallization equipment usually discharges the secondary steam generated by the crystallizer directly or discharges it after being condensed by a condensing device. This not only wastes the latent heat of the secondary steam and wastes energy, but also has to add a set of condensing equipment for condensing the secondary steam, which not only increases investment but is not environmentally friendly and economical. Also, traditional crystallization equipment generally evaporates under normal pressure, which is unfavorable for some heat-sensitive materials that require low-temperature evaporation. For this reason, crystallizers that can produce continuously, save energy and evaporate at low temperature have become a research hotspot.

Contents of the invention

The purpose of the present invention is to provide a continuous crystallizer capable of continuous feeding and discharging, saving energy and evaporating at a lower temperature.

The object of the present invention is achieved like this: the forced circulation continuous crystallization system with mechanical vapor recompression, comprises crystallizer, also comprises compressor, is provided with the heater of lower sealing head (28) and upper sealing head (29), so The bottom of the crystallizer (1) is connected to the circulation pipe (16), the other end of the circulation pipe is connected to the feed port of the circulation pump (11), and the discharge port of the circulation pump is connected to the discharge pipe (17). The other end of the pipe (17) is connected to the feed port of the discharge pump (10), and the discharge port of the discharge pump (10) is connected to the finished product tank (9), and the top of the crystallizer is connected to the compressor inlet through a pipeline (27). The lower head (28) of the heater is connected to the circulation pipe (16), and one side of the lower head is connected to the feed pipe (30). The feed pipe is provided with a ball valve (31) and a feed pump (12). The other end of the pipe is connected with the raw material tank; the upper head of the heater is connected with the crystallizer through a pipeline (18), and a shell side is arranged outside the heater, and the shell side is communicated with the outlet of the compressor (2) through a pipeline (19). The heater is connected to the evacuation pipe (20), and the shell side is connected to the condensed water discharge pipe (21).

The equipment provided by the present invention can meet the crystallization production requirements of continuous feeding and discharging, adopts the compressor to collect the secondary steam, reuses the latent heat of the secondary steam, saves energy, saves the condensing equipment, and reduces the consumption of cooling water. The dosage reduces the cost of the enterprise and increases the income of the enterprise. The water circulation vacuum pump is used to pump out the non-condensable gas and maintain the vacuum in the system to ensure that the solution boils and evaporates at a lower saturation temperature.

In order to maintain the vacuum degree of the system, a balance pipe (22), a ball valve (5) and a vacuum pump (6) are successively arranged on the described evacuation pipe, a ball valve (23) is arranged on the described balance pipe, and the end of the balance pipe is connected with the condensation tank (24 ) connected.

In order to discharge the condensed water after steam condensation, the condensed water discharge pipe is provided with a sight tube (7) and a ball valve (25) in sequence, the end of the condensed water discharge pipe is connected with the condensation tank, and the bottom of the condensation tank is provided with an emptying pipe. A ball valve (26) and an emptying pump (8) are successively arranged on the emptying pipe.

In order to maintain pressure balance, the compressor is a Roots compressor, the inlet and outlet of the compressor are provided with a bypass pipe (32), and the bypass pipe is provided with a ball valve (3).

As a further improvement of the present invention, there is a baffle plate (36) at the top of the crystallizer, and the pipeline (18) entering the crystallizer is provided with an elbow (33) deep to the center line of the crystallizer and upwards along the center line, A conical funnel (37) is arranged at the end, and this structure can control the size of crystal particles to meet production requirements.

In order to preheat the raw material, a heat exchanger (15) is arranged inside the raw material tank.

Description of drawings

Fig. 1 is a kind of structure diagram of the present invention.

Among them, 1-crystallizer, 2-compressor, 3-ball valve, 4-heater, 5-ball valve, 6-vacuum pump, 7-sight tube, 8-emptying pump, 9-finished product tank, 10-discharging pump , 11-circulation pump, 12-feed pump, 13-flow meter, 14-raw material tank, 15-heat exchanger, 16-circulation pipe, 17-outlet pipe, 18-pipeline, 19-pipeline, 20-evacuation Pipeline, 21-condensate discharge pipe, 22-balance pipe, 23-ball valve, 24-condensation tank, 25-ball valve, 26-ball valve, 27-pipeline, 28-lower head, 29-upper head, 30-inlet Material pipe, 31-ball valve, 32-bypass pipe, 33-shell side.

Detailed ways

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

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. The heated feed liquid is sent to the crystallizer 1 for separation, and the concentrated feed liquid falls to the crystallizer 1 The crystal slurry is formed at the bottom of the bottom, and a part of the crystal slurry enters the discharge pipe 17 through the circulation pipe 16 and the circulation pump 11, and the crystal slurry is continuously discharged to the finished product tank 9 through the discharge 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 after being compressed by the compressor 2 to increase the temperature and pressure, it is sent to the heater tube side to release latent heat to heat the solution in the heat exchange tube 35. The condensed water is discharged to the condensate tank 24 through the condensate discharge pipe 21. The lower part of the condensate pipe is equipped with an emptying pipe. The emptying pipe is provided with a ball valve 26 and an emptying pump 8. When the condensing tank is full, it can be drained by the emptying pump. Condensate drained. The inlet and outlet of the compressor are connected to each other by a bypass pipe 32, and the bypass pipe is provided with a ball valve 3, which can protect the compressor from being overloaded due to excessive load when starting and stopping. In order to evaporate the feed liquid at low temperature, the vacuum 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 installed on the evacuation pipe in front of the vacuum pump to control the vacuum degree of the system. Before the ball valve of the evacuation pipe, there is a balance pipe 22 connected to the condensation tank, and a ball valve 23 is arranged on the balance pipe.

Claims (7)

1. A forced circulation continuous crystallization system with mechanical vapor recompression, comprising a crystallizer, is characterized in that: it also includes a compressor, a heater provided with a lower head (28) and an upper head (29), and the crystallizer (1) the bottom is connected to the circulation pipe (16), the other end of the circulation pipe is connected to the feed inlet of the circulation pump (11), and the discharge port of the circulation pump is connected to the discharge pipe (17), and the discharge pipe (17) ) is connected to the feed port of the discharge pump (10), the discharge port of the discharge pump (10) is connected to the finished product tank (9), the top of the crystallizer is connected with the compressor inlet by a pipeline (27), and the heater's The lower head (28) is connected to the circulation pipe (16), one side of the lower head is connected to the feed pipe (30), the feed pipe is provided with a ball valve (31) and a feed pump (12), and the other end of the feed pipe It is connected with the raw material tank; the upper head of the heater is connected with the crystallizer through the pipeline (18), and the shell side is arranged outside the heater, and the shell side is communicated with the outlet of the compressor (2) through the pipeline (19), and the heater Connect the evacuation pipe (20), and connect the condensed water discharge pipe (21) to the shell side. 2. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: the evacuation pipeline is successively provided with a balance pipe (22), a ball valve (5) and a vacuum pump (6). A ball valve (23) is arranged on the balance pipe, and the end of the balance pipe is connected with the condensation tank (24). 3. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: the condensed water discharge pipe is successively provided with a sight tube (7) and a ball valve (25), and the condensed water discharge pipe The end is connected with the condensation tank, and the bottom of the condensation tank is provided with an emptying pipe, and a ball valve (26) and an emptying pump (8) are sequentially arranged on the emptying pipe. 4. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: the compressor is a Roots compressor, and the inlet and outlet of the compressor are provided with bypass pipes (32 ), and a ball valve (3) is provided on the bypass pipe. 5. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: there is a baffle (36) at the top of the crystallizer. 6. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: pipeline (18) is arranged on the central axis of crystallizer at the inner end of crystallizer, and the end of pipeline (18) Connect a conical funnel (37) that opens upwards. 7. The forced circulation continuous crystallization system with mechanical vapor recompression according to claim 1, characterized in that: a heat exchanger (15) is arranged in the raw material tank.

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