Granulation cooling water circulation system

Abstract

The utility model discloses a pelletizing cooling water circulation system in the technical field of chinlon 6 pelletizing process, which comprises a pelletizer, a filter, a water storage tank, a circulating pump and a fine filter which are sequentially connected, achieves the effect of continuously recycling cooling water, filters the cooling water, prevents caprolactam from excessively crystallizing in the circulating water, and improves the quality of the cooling water. And the heat exchanger is additionally arranged to continuously cool circulating water, and the device can filter, collect, cool and recycle cooling water. The cooling water is subjected to subsequent treatment, the problems of waste of the cooling water and environmental pollution are avoided, caprolactam generated during pelletizing can be recycled, and loss is reduced; the spray tower is additionally arranged, so that water vapor mixed smoke of caprolactam can be subjected to spray washing treatment, the generated smoke is subjected to spray dissolution and dust removal, caprolactam in gas is dissolved in water and then treated and recycled, water vapor generated subsequently is not wasted, and cooling is performed to form water recycling.

Description

Technical Field

[0001] This utility model relates to the field of nylon 6 pelletizing technology, and in particular to a pelletizing cooling water circulation system. Background Technology

[0002] Currently, pelletizing circulating water treatment uses a polymerization process. The caprolactam melt after the polymerization reaction is at 250°C and needs to be pelletized. However, caprolactam is in a molten state at high temperatures, which is viscous and not hard enough, making it impossible to meet the pelletizing conditions. Therefore, it is necessary to immerse the caprolactam melt in low-temperature water at 14-17°C to allow the caprolactam melt to cool and harden rapidly, making it easier to pelletize.

[0003] After heat exchange, the pelletizing water will be heated by the caprolactam melt, and as the processing progresses, a large amount of caprolactam will continuously dissolve in the cooling water, forming a caprolactam aqueous solution, and the concentration will continue to increase. When the temperature drops or the concentration approaches saturation, the caprolactam will crystallize and adhere to the pelletizing and cooling water tank walls, affecting the pelletizing operation.

[0004] When high-temperature caprolactam melt comes into contact with cooling water, it evaporates a small amount of water vapor and also forms fumes. Some of the fumes dissolve in the cooling water, while some evaporates to the top of the equipment. The fumes contain a large amount of caprolactam, which mixes with the water vapor to form a mixed gas. This gas is not abundant, and in the past, when we did not understand its properties, it was treated as water vapor. However, after it was transported through pipelines, we found that caprolactam crystals and scale would adhere to the subsequent water vapor treatment equipment.

[0005] The problems encountered in the pelletizing equipment mentioned above need to be effectively resolved. Not only does the cooling water need to be recycled to reduce the loss of caprolactam solution and avoid direct discharge that pollutes the environment, but the mixed steam also needs to be centrally treated to protect the environment and prevent caprolactam from adhering and causing scaling and damage to the steam recovery equipment.

[0006] Based on this, the present invention designs a pelletizing cooling water circulation system to solve the above problems. Utility Model Content

[0007] The purpose of this invention is to provide a pelletizing cooling water circulation system. This device can filter, collect, cool, and recycle cooling water. This achieves subsequent treatment of the cooling water, avoiding waste and environmental pollution. It also recovers and reuses caprolactam generated during pelletizing, reducing losses. Furthermore, it sprays and washes the water vapor mixture of caprolactam, dissolving and removing dust from the generated fumes. The caprolactam in the gas is dissolved in water for further treatment and recycling, effectively recovering and utilizing caprolactam and preventing environmental pollution. The water vapor generated is not wasted but cooled and recycled.

[0008] This utility model is implemented as follows: a pelletizing cooling water circulation system, comprising:

[0009] Pelletizer, filter, water storage tank, spray tower, circulating pump and fine filter;

[0010] The pelletizer is a closed cooling water tank. The blades of the pelletizer are below the liquid surface of the tank. An exhaust hood is installed on the top of the cooling water tank of the pelletizer. The exhaust port of the exhaust hood is connected to the inner cavity of the spray tower. The drain ports of the pelletizer and the spray tower are both connected to the inlet of the filter.

[0011] The water storage tank is a single tank body. A partition is vertically installed inside the water storage tank, which divides the water storage tank into two separate tank bodies that are isolated from each other. The water outlets of the two tank bodies are connected to the same water outlet pipe through a T-junction.

[0012] The rear end of the water outlet pipe is connected to the spray pump and the circulation pump respectively via a tee, and the spray pump and the circulation pump are installed on two different pipelines.

[0013] The rear end of the spray pump is also connected to the inlet of the spray tower and the filter, respectively.

[0014] The outlet of the filter is individually connected to the left and right sides of the water storage tank.

[0015] The left and right sides of the water storage tank are also connected to the same water supply pipe through separate water pipes; the water supply pipe is connected to an external demineralized water supply.

[0016] A fine filter is also installed at the rear end of the circulating pump, and the outlet of the fine filter is connected to the inlet of the pelletizer.

[0017] Furthermore, a smoke exhaust fan is installed inside the exhaust hood.

[0018] Furthermore, the filter is a box-type filter.

[0019] Furthermore, the device also includes a heat exchanger, which is a shell-and-tube heat exchanger; the heat exchanger is installed on the connecting pipe between the fine filter and the pelletizer inlet.

[0020] Furthermore, a three-way valve is installed at the outlet end of the water outlet pipe, and the spray pump and circulation pump are connected to the water outlet pipe through the three-way valve.

[0021] The beneficial effects of this utility model are: 1. This utility model adds a complete water circulation pipeline system, which can recycle and reuse the cooling water in the pelletizer cooling water tank. The cooling water is filtered through a filter, collected through a storage tank, and transported and cooled again through a circulation pump and heat exchanger to achieve the purpose of cooling water recycling. The entire water circulation pipeline can separate and dissolve caprolactam in the cooling water and recycle it. It can also cool the pelletizer water tank and keep it in a cooling state.

[0022] 2. A fine filter has been added, which can continuously filter the circulating water, effectively separate and recover caprolactam dissolved in the cooling water, and the recovery and separation are more convenient.

[0023] 3. This device also includes a spray tower, which can adsorb and purify caprolactam fumes, dissolving caprolactam in water mist and spray water jets. It can also cool the water vapor in the fumes, turning it back into liquid water, thus achieving the goal of simultaneously recycling water and caprolactam without any waste or exhaust emissions. This protects the environment while reducing the additional consumption of water and caprolactam. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic diagram of the structure of this utility model.

[0026] The attached diagram lists the components represented by each number as follows:

[0027] 1-Pelletizer, 11-Exhaust hood, 12-Drain pipe, 2-Filter, 3-Water storage tank, 31-Baffle, 32-Outlet pipe, 33-Make-up pipe, 34-Three-way valve, 4-Spray tower, 41-Spray pump, 5-Circulation pump, 51-Fine filter, 52-Heat exchanger. Detailed Implementation

[0028] Please see Figure 1 As shown, this utility model provides a pelletizing cooling water circulation system. To better understand the above technical solution, the following will describe the above technical solution in detail with reference to the accompanying drawings and specific embodiments.

[0029] In a specific embodiment of the technical solution of this utility model:

[0030] Includes pelletizer 1, filter 2, water storage tank 3, spray tower 4, circulating pump 5, and fine filter 51;

[0031] The pelletizer 1 is a closed cooling water tank. The blades of the pelletizer 1 are located below the water surface in the tank. An exhaust hood 11 is installed on the top of the cooling water tank of the pelletizer 1. The exhaust port of the exhaust hood 11 is connected to the inner cavity of the spray tower 4. The drain ports of both the pelletizer 1 and the spray tower 4 are connected to the inlet of the filter 2. The drain ports of the pelletizer 1 and the spray tower 4 are connected to the inlet of the filter 2 through a T-junction. An exhaust fan is installed inside the exhaust hood 11 to facilitate the timely delivery of the smoke generated by the pelletizer 1 into the spray tower 4. The exhaust fan of the exhaust hood 11 will also discharge the smoke into the bottom of the inner cavity of the spray tower 4, which will facilitate the flushing with the water mist, effectively dissolving caprolactam and recovering water vapor.

[0032] The water tank 3 is a tank body. A partition 31 is vertically installed inside the water tank 3. The water tank 3 is divided into two separate tanks on the left and right sides by the partition 31. The water outlets of the two tanks on the left and right sides of the water tank 3 are connected to the same water outlet pipe 32 through a T-junction.

[0033] A three-way valve 34 is installed at the outlet end of the water outlet pipe 32. The rear end of the water outlet pipe 32 is connected to the spray pump 41 and the circulation pump 5 through the three-way valve 34. The spray pump 41 and the circulation pump 5 are installed on two different pipelines.

[0034] The rear end of the spray pump 41 is also connected to the inlet of the spray tower 4 and the filter 2 respectively;

[0035] Filter 2 is a box-type filter, and the outlet of filter 2 is connected to the left and right sides of the water storage tank 3 separately.

[0036] The left and right sides of the water storage tank 3 are also connected to the same water supply pipe 33 via separate water pipes; the water supply pipe 33 is connected to an external demineralized water supply and can also purify the circulating water. When needed, demineralized water can be injected to quickly reduce the caprolactam concentration in the circulating water;

[0037] A fine filter 51 is installed at the rear end of the circulating pump 5, and the outlet of the fine filter 51 is connected to the inlet of the pelletizer 1. The fine filter 51 can be a separation tower, allowing the entire fine filter 1 to easily recover caprolactam. A heat exchanger 52 is installed at the rear end of the fine filter 51. The heat exchanger 52 is a shell-and-tube heat exchanger; the heat exchanger 52 is installed on the connecting pipe between the fine filter 51 and the inlet of the pelletizer 1.

[0038] It should be noted that:

[0039] 1. The water tank of pelletizer 1 is generally designed according to the length of the pelletizing process. To cool the pellets quickly, its capacity is usually not too small. However, the coarse filter 2, which serves as a temporary transition tank for the pelletizing water, has a relatively small capacity. This makes it difficult to control the flow of cooling water and the liquid level in the storage tank of pelletizer 1, easily leading to overflow. This device adds a water storage tank 3 to store and guide the cooling water from filter 2 and pelletizer 1, and to achieve a buffering and initial cooling effect. 2. During prolonged operation of the pelletizer, crystal particles continuously crystallize in the subsequent water circulation system, especially after the water cools down, the amount of crystallization increases continuously. In addition, the water storage tank needs to be cleaned frequently. When switching between cleaning, the water flow control is unstable, which can easily cause the water tank of pelletizer 1 to run out of water and stop, or it may overflow, affecting production. 3. Because the water storage tank 3 is difficult to clean, the cleaning frequency is generally reduced as much as possible. This can easily lead to bacterial fermentation and scale formation in the water storage tank 3. The scale adheres to the pipe wall and the inner wall of the equipment, affecting the water flow and heat exchange effect. The scale in the pelletizing cooling water is hard, which will put a burden on the entire water circulation pipeline. The treatment effect is not good, which can easily cause pelletizer 1 to stop frequently. It can also flow into the water tank of pelletizer 1, causing severe wear of the cutter blade, ultimately affecting the stability of production.

[0040] In use, molten caprolactam is continuously extruded through an extrusion hole and a screw conveyor to form a long strip shape, which is then continuously fed into the water tank of the pelletizer 1. The molten caprolactam is cooled and solidified by the cooling water in the pelletizer 1. At this time, the high-temperature caprolactam at 250°C comes into contact with the cooling water, and it evaporates the cooling water to form water vapor. The caprolactam itself also volatilizes into a gaseous state due to the high temperature, and the bubbles rise rapidly. The bubbles and the cooling water form an ion membrane. The gas is difficult to dissolve in a large amount of water, and most of it floats to the surface and is collected by the exhaust hood 11. It is then transported to the spray tower 4 through the exhaust pipe by the exhaust fan. The water flow or water mist sprayed by the spray pump 41 absorbs and cools the smoke, dissolves the caprolactam smoke in the water, and cools the water vapor back to liquid water, thereby completely absorbing the smoke without exhaust gas emission. The aqueous solution of the spray tower 4 is then sent to the filter 2 to recover the smoke.

[0041] Caprolactam forms a brittle, hard solid within pelletizer 1. Pelletizer 1 cuts the solidified caprolactam into slices. For example... Figure 1 As shown, the materials are transported from left to right to the next process stage.

[0042] The cooling water will heat up during the continuous pelletizing process, making it difficult to continue to achieve rapid cooling. Therefore, the cooling water in the pelletizer 1 water tank of this device is continuously circulated to keep the cooling water at a suitable water temperature for a long time.

[0043] The cooling water from pelletizer 1 flows into filter 2, which is a coarse particle filter. It is easy to filter out the chip fragments that are trapped in the pelletizer and can be easily retrieved. Therefore, filter 2 can be a device that makes it easy to replace the filter screen.

[0044] The pre-filtered caprolactam aqueous solution enters the storage tank 3 and is then drained through the outlet pipe 32. The direction and degree of water flow are controlled by the three-way valve 34. Both sides can be opened slightly, or only one side can be opened. When the smoke from the spray tower 4 needs to be treated, the spray pump 41 is turned on to flush the smoke with water to dissolve the caprolactam and condense the water vapor into liquid water.

[0045] The circulating pump 5 delivers water to the fine filter 51, which filters or separates caprolactam and fine particles in the water, thereby separating the caprolactam aqueous solution into water and caprolactam. The circulating water is then cooled by the heat exchanger 52 and finally sent to the pelletizer 1. At this time, the purified water replenishes the cooling water in the pelletizer 1, achieving the purpose of continuous circulation of cooling water and keeping the cooling water in the pelletizer 1 clean and at a low temperature.

[0046] The water tank 3 is divided into two independent chambers, left and right, by the partition 31. It can be used independently on one side or opened simultaneously, as long as a valve is installed on the pipeline.

[0047] Especially when it is necessary to clean the water tank 3, the circulating water can be reused on one side to ensure the normal operation of the pelletizer 1, and the left and right sides can be cleaned separately in turn.

[0048] After cleaning one side of the cavity, the water supply pipe 33 is opened to inject clean demineralized water into the cleaned water storage tank 3 cavity, so that the circulating water is replenished and purified. When cleaning the other side, demineralized water is also injected. In this way, after cleaning, not only is the circulating water purified, but it is also equivalent to replacing the entire circulating water. The replaced circulating water can be discharged into the extraction water pipeline through the water storage tank 3 or the fine filter 51 for centralized treatment in subsequent processes.

[0049] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A pelletizing cooling water circulation system, characterized in that, include: Pelletizer (1), filter (2), water storage tank (3), spray tower (4), circulating pump (5) and fine filter (51); The pelletizer (1) is a closed cooling water tank. The blades of the pelletizer (1) are below the liquid surface of the tank. An exhaust hood (11) is installed on the top of the cooling water tank of the pelletizer (1). The exhaust port of the exhaust hood (11) is connected to the inner cavity of the spray tower (4). The drain ports of the pelletizer (1) and the spray tower (4) are both connected to the inlet of the filter (2). The water tank (3) is a tank body. A partition (31) is vertically installed inside the water tank (3). The water tank (3) is divided into two separate tank bodies on the left and right by the partition (31). The water outlets of the left and right tank bodies of the water tank (3) are connected to the same water outlet pipe (32) through a tee. The rear end of the water outlet pipe (32) is connected to a spray pump (41) and a circulation pump (5), respectively, and the spray pump (41) and the circulation pump (5) are set on two different pipelines; The rear end of the spray pump (41) is also connected to the inlet of the spray tower (4) and the filter (2); The outlet of the filter (2) is connected separately to the left and right sides of the water tank (3); The left and right sides of the water storage tank (3) are also connected to the same water supply pipe (33) through separate water pipes; the water supply pipe (33) is connected to an external demineralized water supply. A fine filter (51) is also provided at the rear end of the circulating pump (5), and the outlet of the fine filter (51) is connected to the inlet of the pelletizer (1).

2. The pelletizing cooling water circulation system according to claim 1, characterized in that: A smoke exhaust fan is installed inside the exhaust hood (11).

3. The pelletizing cooling water circulation system according to claim 1, characterized in that: The filter (2) is a box-type filter.

4. The pelletizing cooling water circulation system according to claim 1, characterized in that: It also includes a heat exchanger (52), which is a shell-and-tube heat exchanger; the heat exchanger (52) is installed on the connecting pipe between the fine filter (51) and the inlet of the pelletizer (1).

5. The pelletizing cooling water circulation system according to claim 1, characterized in that: A three-way valve (34) is installed at the outlet end of the water outlet pipe (32), and the spray pump (41) and the circulation pump (5) are connected to the water outlet pipe (32) through the three-way valve (34).

Images