Water repellent device and water repellent method for recovering nitrocellulose

Abstract

The application discloses a water removal device for recycling nitrocellulose, which comprises a water-cotton concentration tank, a centrifuge inlet connected to the water-cotton concentration tank through a water-cotton pump, a concentrated alcohol tank connected to the centrifuge inlet, and a uniform mixer connected to a centrifuge outlet; and the application also discloses a water removal method for recycling nitrocellulose, which comprises the following steps: conveying recycled nitrocellulose to a vertical centrifuge, and adjusting the concentration of water removal alcohol and the water removal process to replace and prolong the water removal time, so as to realize safe production and normal water removal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nitrocellulose dewatering process, and relates to a dewatering device for recycling nitrocellulose.

[0002] The application also relates to a dewatering method for recycling nitrocellulose. BACKGROUND

[0003] In the production process of nitrocellulose, a large amount of water is needed for boiling, washing and dewatering, and therefore a considerable amount of fine nitrocellulose enters the wastewater, which brings difficulty to wastewater treatment and increases the production cost. Therefore, the nitrocellulose in the wastewater is recycled, and the recycled nitrocellulose is dewatered and packaged, which is a key link in the production process. Because the fiber is fine, it is difficult to realize dewatering through normal product supply, and therefore the dewatering process (alcohol adding time, dewatering time and centrifuge speed) of the recycled nitrocellulose is obviously strengthened compared with that of normal products (non-recycled nitrocellulose), otherwise the qualified moisture result cannot be achieved. However, prolonging the dewatering time and increasing the amount of alcohol (alcohol adding time) brings safety risks, and therefore a set of recycling cellulose dewatering process method is researched, which can realize the dewatering target without adopting the conventional dewatering process method. SUMMARY

[0004] The application aims to provide a dewatering device for recycling nitrocellulose, and solves the problem of long dewatering time in the prior art.

[0005] Another object of the application is to provide a dewatering method for recycling nitrocellulose.

[0006] The first technical solution adopted by the application is a dewatering device for recycling nitrocellulose, which comprises a water-cotton concentration tank, the water-cotton concentration tank is connected with a centrifuge inlet through a water-cotton pump, the centrifuge inlet is also connected with a concentrated alcohol tank, and the centrifuge outlet is connected with a uniform mixer.

[0007] The second technical solution adopted by the application is a dewatering method for recycling nitrocellulose, which adopts the dewatering device for recycling nitrocellulose and is implemented according to the following steps.

[0008] Step 1, the recycled nitrocellulose is put into the water-cotton concentration tank and is pumped into the vertical centrifuge through the water-cotton pump.

[0009] Step 2, the concentrated alcohol is prepared and is added into the centrifuge to start the dehydration work.

[0010] Step 3, the dehydrated nitrocellulose is put into the uniform mixer for stirring, discharging and packaging.

[0011] The second technical solution adopted by the application has the following characteristics.

[0012] The concentration of the concentrated alcohol in step 2 is 92%-93% V / V.

[0013] The dehydration time in step 2 is 50s-60s.

[0014] The concentrated alcohol adding time in step 2 is 150s, and the water removal time is 300s-350s.

[0015] In step 3, the dehydrated nitrocellulose is put into the homogenizer for stirring for 2min-3min, and then discharged and packaged.

[0016] The beneficial effects of the present application are

[0017] The water removal device for recycling nitrocellulose of the present application uses the improved new process, which not only saves the amount of alcohol, shortens the water removal production time, but also more importantly reduces the risk of safe production. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic view of the water removal device for recycling nitrocellulose of the present application.

[0019] In the figure, 1 is a water cotton concentration tank, 2 is a water cotton pump, 3 is a centrifuge, 4 is a concentrated alcohol tank, and 5 is a homogenizer. DETAILED DESCRIPTION

[0020] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0021] The present application provides a water removal device for recycling nitrocellulose, as shown in Figure 1 Specifically includes a centrifuge 3, the centrifuge 3 inlet is connected with a water cotton concentration tank 1 and a concentrated alcohol tank 4 respectively, the water cotton concentration tank 1 is connected with the centrifuge 3 through a water cotton pump 2, and the centrifuge 3 outlet is connected with a homogenizer 5; the present application is to deliver the recycled nitrocellulose to a vertical centrifuge, and to realize safe production and normal water removal by adjusting the water removal alcohol concentration and replacing the prolonged water removal time.

[0022] The present application also provides a water removal method for recycling nitrocellulose, which uses the improved new process, not only saves the amount of alcohol, shortens the water removal production time, but also more importantly reduces the risk of safe production, the original water removal time is reduced from 600s-1500s to 300s-350s, and the safety of production is improved.

[0023] The recycled nitrocellulose is difficult to be dewatered because of the fine cotton powder, low nitrogen content (low molecular weight) and easy dissolution in alcohol during the dewatering process. Therefore, the alcohol input is increased and the dewatering time is prolonged to meet the quality requirements. Based on the product characteristics, low-concentration alcohol dewatering is adopted to reduce the product dissolution and shorten the dewatering time. The specific implementation steps are as follows:

[0024] Step 1: The nitrocellulose product is recovered from the wastewater or recycled water in the front process of the nitrocellulose production process, and is fed into the dewatering thickener, i.e. water cotton thickening tank 1, to increase the product concentration and facilitate the dewatering of the centrifuge. The water cotton pump 2 is used to feed the product into the vertical centrifuge 3 at a low speed of 300-350 R / min. If the speed is too high, the product is too fine and difficult to be dewatered.

[0025] Step 2: Considering that the conventional dewatering adopts alcohol with a concentration of 95% V / V, the product is prone to dissolution during the dewatering process due to the high alcohol concentration, which leads to adhesion to the screen and is not conducive to dewatering. Therefore, the alcohol concentration is reduced. After several tests, the alcohol concentration is not too low, and the final concentration of the prepared concentrated alcohol is 92%-93% V / V. The amount of alcohol is determined according to the production requirements. The preparation process is realized by calculation and water addition in the alcohol tank 4. The dewatering work starts directly by feeding the alcohol into the centrifuge 3. The dewatering time is 50-60 s, the alcohol addition time is 150 s, and the dewatering time is 300-350 s. The dewatering time of the conventional recycled nitrocellulose is 600-1500 s. The specific dewatering time is determined according to the quality indicators of the product after dewatering. The moisture content is usually controlled below 7%, and the wetting agent is 28-32%. Generally, 300-350 s is sufficient. The centrifuge speed is the same as that of the normal product. After dewatering, the product is directly discharged.

[0026] Step 3: The dewatered nitrocellulose is fed into the homogenizer for stirring for 2-3 min, and then is discharged and packaged.

Claims

1. A water-removing method for recovering nitrocellulose, characterized in that, The water-driving device used for recycling nitrocellulose includes a water-cellulose concentration tank (1), which is connected to the inlet of a centrifuge (3) via a water-cellulose pump (2). The inlet of the centrifuge (3) is also connected to a concentrated wine tank (4), and the outlet of the centrifuge (3) is connected to a homogenizer (5). The specific steps are as follows: Step 1: The recovered nitrocellulose is fed into the water-coated thickening tank (1) and pumped into the vertical centrifuge (3) by the water-coated pump (2). Step 2: Prepare concentrated alcohol in the concentrated liquor tank (4) and add it to the centrifuge (3) to start the dehydration process; Step 3: The dehydrated nitrocellulose is fed into a homogenizer (5) for mixing, discharging, and packaging. In step 2, the concentration of concentrated alcohol is 92%-93% V / V; The dehydration time in step 2 is 50s~60s; In step 2, the concentrated alcohol is added at a time of 150 seconds, and the water removal time is 300 to 350 seconds. In step 3, the dehydrated nitrated cellulose is fed into a homogenizer and stirred for 2 to 3 minutes before being discharged and packaged.

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