Paraformaldehyde concentrating and drying system

Abstract

The utility model belongs to the technical field of high-molecular compounds, and particularly relates to a paraformaldehyde concentrating and drying system which comprises a falling-film evaporator, the falling-film evaporator is connected with a granulation tank, a liquid distributor and a falling-film channel are arranged in the falling-film evaporator, the bottom of the falling-film evaporator is connected with a shell-and-tube heat exchanger, and the shell-and-tube heat exchanger is connected with the liquid distributor. An air heater is arranged on the lower portion of the granulation tank, an air guide pipe and a material spraying nozzle are arranged in the granulation tank, the air guide pipe is communicated with the air heater, a material conveying pump is arranged between the falling film evaporator and the granulation tank, a heat exchange sleeve is arranged outside the granulation tank, and an air pump is connected to the top of the granulation tank. According to the utility model, paraformaldehyde is concentrated and dried to obtain granular paraformaldehyde products.

Description

Technical Field

[0001] This invention belongs to the field of polymer compound technology, specifically relating to a paraformaldehyde concentration and drying system. Background Technology

[0002] Concentration and drying of paraformaldehyde is a core step in the paraformaldehyde production process, directly affecting the degree of polymerization, purity, and physical form of the final product. External heating provides energy, causing moisture and a small amount of formaldehyde to evaporate, while simultaneously disrupting the equilibrium of the "formaldehyde-water-paraformaldehyde" system, driving the polymerization reaction towards the formation of higher molecular weight solid paraformaldehyde.

[0003] In modern industry, spray drying is the dominant method, its core being the use of instantaneous high temperatures to achieve a balance between rapid dehydration and deep polymerization. The key to spray drying lies in overcoming a series of challenges, including wall adhesion, dust explosions, product degradation, and environmental impact assessments. Through precise equipment design and strict process control, high-quality, stable paraformaldehyde products are ultimately obtained. However, currently used paraformaldehyde concentration and drying equipment suffers from problems such as complex operation and low efficiency. Utility Model Content

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a paraformaldehyde concentration and drying system that can obtain paraformaldehyde particles with uniform particle size and improve the production efficiency of paraformaldehyde particles.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] The paraformaldehyde concentration and drying system of this utility model includes a falling film evaporator connected to a granulation tank. The falling film evaporator is equipped with a liquid distributor and a falling film channel inside. A shell-and-tube heat exchanger is connected to the bottom of the falling film evaporator and is connected to the liquid distributor. A hot air fan is installed at the bottom of the granulation tank. A gas guide pipe and a material spray nozzle are installed inside the granulation tank. The gas guide pipe is connected to the hot air fan. A feed pump is installed between the falling film evaporator and the granulation tank. A heat exchange jacket is installed outside the granulation tank. An air pump is connected to the top of the granulation tank.

[0007] in:

[0008] The liquid distributor is positioned above the falling film channel.

[0009] The liquid distributor includes an upper dispersion baffle and a bottom guide channel, and the dispersion baffle is provided with several through holes.

[0010] A flow divider plate is provided at the bottom of the flow guide channel. The two ends of the flow divider plate are fixed to the inner wall of the flow guide channel. The flow divider plate is arranged in an inverted V shape.

[0011] The spray nozzle is located in the middle of the side wall of the granulation tank, and the air guide pipe is vertically located on the side of the granulation tank away from the spray nozzle. The spray nozzle and the air guide pipe are arranged opposite each other.

[0012] The spray nozzle is triangular in shape, and the spray direction of the spray nozzle is inclined upward.

[0013] The tilt angle of the spray nozzle is 15-30°.

[0014] The air duct is provided with several air outlets.

[0015] The bottom of the granulation tank is funnel-shaped, and a discharge port is provided at the center of the bottom of the funnel-shaped structure.

[0016] The heat exchange jacket is provided with a heat exchange inlet at the top and a heat exchange outlet at the bottom. The top of the falling film evaporator is connected to the heat exchange inlet of the heat exchange jacket.

[0017] The beneficial effects of this utility model are:

[0018] This invention concentrates and dries paraformaldehyde to obtain granular paraformaldehyde products. The concentration process uses falling film evaporation, which increases the concentration of the paraformaldehyde solution and reduces the water content evaporated during the subsequent granulation process. The liquid distributor ensures that the paraformaldehyde solution entering the falling film evaporator falls evenly and is not affected by the feed rate. The liquid-feed circulation formed between the tube heat exchanger and the falling film evaporator greatly increases the flow rate of the paraformaldehyde solution, promoting the continuous evaporation and discharge of water from the paraformaldehyde solution. In the granulation tank, the concentrated paraformaldehyde solution is dispersed into smaller droplets and sprayed upwards at an angle, forming convection with the hot air sprayed from the upper part of the air guide pipe. Subsequently, as the paraformaldehyde falls, it is further dried by the hot air sprayed from the middle of the air guide pipe, ensuring the formation of paraformaldehyde particles and guaranteeing the uniformity of particle size. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the liquid distributor structure of this utility model;

[0021] Figure 3 This is a schematic diagram of the flow guiding channel structure of this utility model;

[0022] In the diagram: 1. Falling film evaporator; 2. Granulation tank; 3. Hot air blower; 4. Liquid distributor; 5. Air guide pipe; 6. Feed pump; 7. Spray nozzle; 8. Heat exchange jacket; 9. Air pump; 10. Falling film channel; 11. Shell and tube heat exchanger; 201. Discharge port; 401. Dispersion baffle; 402. Flow guide channel; 403. Flow divider; 501. Air outlet. Detailed Implementation

[0023] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0024] Example 1

[0025] like Figure 1-3 As shown, the paraformaldehyde concentration and drying system of this utility model includes a falling film evaporator 1, a granulation tank 2 connected to the falling film evaporator 1, a liquid distributor 4 and a falling film channel 10 inside the falling film evaporator 1, a shell-and-tube heat exchanger 11 connected to the bottom of the falling film evaporator 1, the shell-and-tube heat exchanger 11 being connected to the liquid distributor 4, a hot air blower 3 being installed at the bottom of the granulation tank 2, a gas guide pipe 5 and a material spray nozzle 7 being installed inside the granulation tank 2, the gas guide pipe 5 being connected to the hot air blower 3, a material pump 6 being installed between the falling film evaporator 1 and the granulation tank 2, a heat exchange jacket 8 being installed outside the granulation tank 2, and a vacuum pump 9 being connected to the top of the granulation tank 2.

[0026] The liquid distributor 4 is positioned above the falling film channel 10.

[0027] The liquid distributor 4 includes an upper dispersion baffle 401 and a bottom guide channel 402, and the dispersion baffle 401 is provided with several through holes.

[0028] A flow divider plate 403 is provided at the bottom of the flow guide channel 402. The two ends of the flow divider plate 403 are fixed on the inner wall of the flow guide channel 402. The flow divider plate 403 is arranged in an inverted V shape.

[0029] The spray nozzle 7 is located in the middle of the side wall of the granulation tank 2, and the air guide pipe 5 is vertically located on the side of the granulation tank 2 away from the spray nozzle 7. The spray nozzle 7 and the air guide pipe 5 are arranged opposite to each other.

[0030] The spray nozzle 7 is arranged in a triangular shape, and the spray direction of the spray nozzle 7 is tilted upward.

[0031] The tilt angle of the spray nozzle 7 is 15-30°.

[0032] The air duct 5 is provided with several air outlets 501.

[0033] The bottom of the granulation tank 2 is funnel-shaped, and a discharge port 201 is provided at the center of the bottom of the funnel-shaped structure.

[0034] The heat exchange jacket 8 has a heat exchange inlet at the top and a heat exchange outlet at the bottom. The top of the falling film evaporator 1 is connected to the heat exchange inlet of the heat exchange jacket 8.

[0035] Working principle and process:

[0036] During concentration, the paraformaldehyde solution is dispersed into the falling film evaporator 1 through the liquid distributor 4 and flows within the falling film channel 10 of the falling film evaporator 1, forming a liquid film. The paraformaldehyde solution flowing to the bottom of the falling film evaporator 1 is then dispersed again through the liquid distributor 4 after heat exchange in the tube heat exchanger 11. The paraformaldehyde solution circulates and concentrates in the tube heat exchanger 11 and the falling film evaporator 1. The vapor generated from the concentration can be used to heat the granulation tank 2. The concentrated paraformaldehyde solution is then transported to the granulation tank 2 for spraying. In the mist granulation process, the concentrated paraformaldehyde solution is sprayed upwards at an angle through the spray nozzle 7. The hot air is introduced into the air duct 5 by the hot air blower 3 and the air outlet 501 evenly sprays the hot air into the granulation tank 2, where it forms convection with the concentrated paraformaldehyde solution, causing the water in the paraformaldehyde solution to evaporate instantly. The high-temperature steam is then extracted by the vacuum pump 9 to prevent the high-temperature steam from accumulating inside the granulation tank 2, ultimately forming paraformaldehyde particles. The paraformaldehyde particles fall to the bottom of the granulation tank 2, tilt down, and are discharged through the discharge port 201.

Claims

1. A paraformaldehyde concentration and drying system, comprising a falling film evaporator (1), characterized in that, The falling film evaporator (1) is connected to the granulation tank (2). The falling film evaporator (1) is equipped with a liquid distributor (4) and a falling film channel (10). The bottom of the falling film evaporator (1) is connected to a shell and tube heat exchanger (11). The shell and tube heat exchanger (11) is connected to the liquid distributor (4). The bottom of the granulation tank (2) is equipped with a hot air blower (3). The granulation tank (2) is equipped with a gas guide pipe (5) and a material spray nozzle (7). The gas guide pipe (5) is connected to the hot air blower (3). A material pump (6) is installed between the falling film evaporator (1) and the granulation tank (2). A heat exchange jacket (8) is installed outside the granulation tank (2). A vacuum pump (9) is connected to the top of the granulation tank (2).

2. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The liquid distributor (4) is positioned above the falling film channel (10).

3. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The liquid distributor (4) includes an upper dispersion baffle (401) and a bottom guide channel (402), and the dispersion baffle (401) is provided with several through holes.

4. The paraformaldehyde concentration and drying system according to claim 3, characterized in that, A diverter plate (403) is provided at the bottom of the flow channel (402). The two ends of the diverter plate (403) are fixed on the inner wall of the flow channel (402). The diverter plate (403) is arranged in an inverted V shape.

5. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The spray nozzle (7) is located in the middle of the side wall of the granulation tank (2), and the air guide pipe (5) is vertically located on the side of the granulation tank (2) away from the spray nozzle (7). The spray nozzle (7) and the air guide pipe (5) are arranged opposite to each other.

6. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The spray nozzle (7) is arranged in a triangular shape, and the spray direction of the spray nozzle (7) is tilted upward.

7. The paraformaldehyde concentration and drying system according to claim 6, characterized in that, The tilt angle of the spray nozzle (7) is 15-30°.

8. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The air duct (5) is provided with several air outlets (501).

9. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The bottom of the granulation tank (2) is set in a funnel shape, and a discharge port (201) is set at the center of the bottom of the funnel-shaped structure.

10. The paraformaldehyde concentration and drying system according to claim 1, characterized in that, The heat exchange jacket (8) has a heat exchange inlet at the top and a heat exchange outlet at the bottom. The top of the falling film evaporator (1) is connected to the heat exchange inlet of the heat exchange jacket (8).

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