Dehydration method of high-viscosity collodion cotton

Abstract

The invention discloses a dehydration method of high-viscosity collodion cotton, which is characterized by comprising the following steps: step 1, putting a collodion cotton material into a thickener, and the height of the liquid level of the cotton material is 45-55% of the height of a feeding groove of the thickener; 2, the collodion cotton material is heated to 56-60 DEG C at the heating rate of 1 DEG C / min; and step 3, conveying the heated collodion cotton material into a dehydration centrifugal machine for dehydration, reducing the liquid level of the cotton material to 50%, and heating the cotton material to a target temperature at a heating rate of 1 DEG C / min, so that the retention time of the cotton material in a thickener is shortened, the damage of viscosity at a relatively high temperature is slowed down, and the viscosity of the cotton material is reduced by utilizing the short-time high temperature of the cotton material. The problem of difficult dehydration and the damage of high temperature to viscosity are solved, and the viscosity index and the moisture index of the finished product are ensured to be qualified.

Description

Technical Field

[0001] The invention belongs to the technical field of nitrocellulose, and in particular relates to a dehydration method for high-viscosity explosive colloid cotton. Background Art

[0002] High viscosity explosive cotton is a special variety of nitrocellulose products. After nitration, boiling, washing, and fine cutting, the cotton material (10% nitrocellulose pulp aqueous solution) enters the dehydration link for dehydration and packaging. In the packaging process, because the viscosity of the product is particularly high and the finished product moisture index requirement is relatively low, the finished product moisture requirement is 30-35%. Under this moisture index, the cotton material needs to be heated to ensure that the dehydration moisture is qualified, otherwise the product with qualified moisture index cannot be obtained. In the existing dehydration process, the cotton material is first heated to 50-55℃, and then the cotton material is pumped to the centrifuge for dehydration and packaging. However, at this temperature, the moisture content of the finished product is 35-36%, which does not meet the qualified requirements. In order to ensure that the moisture content of the finished product is qualified, the centrifuge water drive temperature needs to be increased. After the cotton material is heated to a higher temperature, the cotton fiber expands, the water filtration effect is good, and the centrifuge is easy to dehydrate, that is, the moisture removal rate is high. However, when the temperature exceeds 55℃, the excessively high temperature has a particularly great impact on the viscosity of the cotton material, resulting in a significant degradation of the inherent viscosity of the cotton material. At 55-60℃, the viscosity of the finished product drops by about 40%. In the actual dehydration process, there is often either unqualified moisture or a large drop in viscosity when the moisture is qualified, resulting in unqualified key indicators of product viscosity and failure to deliver qualified products. Summary of the invention

[0003] The purpose of the present invention is to provide a dehydration method for high-viscosity explosive rubber cotton, which is used to produce a high-viscosity explosive rubber cotton finished product with a moisture content of 32-35% and a viscosity of 7000-9000mPa.s.

[0004] The technical solution adopted by the present invention is a dehydration method of high-viscosity explosive cotton, comprising the following steps:

[0005] Step 1, adding explosive cotton to the concentrator, the cotton material liquid level height is 45-55% of the height of the concentrator feed tank;

[0006] Step 2, heating the explosive cotton material to 56-60°C within 25-30 minutes;

[0007] Step 3, conveying the heated exploded cotton material to a dehydration centrifuge for dehydration.

[0008] The present invention is also characterized in that:

[0009] The cotton concentration of the explosive cotton material in step 1 is 10-13%.

[0010] In step 2, heating is performed using a concentrator steam heating tube.

[0011] The heating in step 2 uses a uniform heating rate.

[0012] The feeding speed in the dehydration centrifuge in step 3 is 15-17 kg / min.

[0013] In step 3, the dehydration centrifuge 5 adopts a P60 centrifuge.

[0014] The heated explosive cotton material in step 3 is transported through a cotton material transport pump.

[0015] The speed of the cotton material conveying pump is 300-330r / min.

[0016] The cotton material liquid level height is 50% of the height of the concentrator feed trough, and the explosive cotton material is heated to 58°C within 30 minutes.

[0017] The beneficial effects of the present invention are:

[0018] The present invention reduces the liquid level of the explosive rubber cotton material in the concentrator from the original 2 / 3 to 1 / 2, and at the same time increases the heating speed of the cotton material in the concentrator, shortens the heating time, and slows down the damage to the viscosity caused by the long heating time, thereby ensuring the improvement of the dehydration rate at high temperature and reducing the loss of the viscosity of the explosive rubber cotton, thereby achieving the production of high-viscosity explosive rubber cotton with qualified moisture index and viscosity index.

[0019] Furthermore, the present invention increases the feed amount of the cotton material conveying pump, specifically controls the feed amount of the cotton material conveying pump by controlling the rotation speed of the cotton material conveying pump, thereby increasing the original rotation speed of 280-290r / min to the current rotation speed of 300-330r / min, thereby accelerating dehydration, reducing the residence time of the cotton material in the concentrator, and further slowing down the destruction of viscosity at higher temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of the present invention.

[0021] 1. Concentrator, 2. Concentrator steam heating pipe, 3. Cotton material conveying pump, 4. Cotton conveying pipeline, 5. Dehydration centrifuge, 6. Centrifugal discharge pipe. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, the present invention utilizes a dehydration device for high-viscosity explosive cotton for dehydration, the device comprises a concentrator 1, a concentrator steam heating tube 2 is installed in the concentrator 1, a cotton material conveying pump 3 is connected to the bottom of the concentrator 1 through a pipeline, the cotton material conveying pump 3 is connected to a dehydration centrifuge 5 through a cotton conveying pipeline 4, a centrifugal discharge pipe 6 is provided at the outlet of the dehydration centrifuge 5, and the dehydration centrifuge 5 adopts a P60 centrifuge.

[0024] When in use, the cotton material is put into the concentrator 1, and the steam heating pipe 2 is turned on to heat the cotton material. After heating, the cotton material with high temperature is easier to dehydrate than the cotton material with low temperature. The heated cotton material is then pumped to the dehydration centrifuge 5 for dehydration and packaging through the cotton material delivery pump 3. The concentrator 1 serves as a feed tank for stably supplying cotton material to the dehydration centrifuge, and has the function of sedimentation, drainage and concentration.

[0025] The dehydration method of high-viscosity explosive cotton provided by the present invention specifically comprises the following steps:

[0026] Step 1, feeding into the concentrator 1, the feeding liquid level is 45-55% of the height of the concentrator feed tank;

[0027] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to increase its temperature at a heating rate of 0.8-1.2°C / min, and heat the material to 56-60°C within 25-30min;

[0028] Step 3, start the cotton material conveying pump 3 and the dehydration centrifuge 5, control the rotation speed of the cotton material conveying pump 3 to 300-330r / min, and transport the material in the concentrator 1 to the dehydration centrifuge 5 through the cotton conveying pipeline 4 for dehydration.

[0029] Example 1

[0030] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0031] Step 1, put the qualified explosive cotton material (cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 50%;

[0032] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 58° C. within 30 minutes;

[0033] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 330r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 17kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0034] Example 2

[0035] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0036] Step 1, put the qualified explosive cotton material (the cotton content in water is 10-13%) into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 55%;

[0037] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 57° C. within 30 minutes;

[0038] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 330r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 17kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0039] Example 3

[0040] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0041] Step 1, put the qualified explosive cotton material (the cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 52%;

[0042] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 60° C. within 30 minutes;

[0043] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 300r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 15kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0044] Example 4

[0045] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0046] Step 1, put the qualified explosive cotton material (the cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 48%;

[0047] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 59° C. within 30 minutes;

[0048] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 310r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 16kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0049] Example 5

[0050] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0051] Step 1, put the qualified explosive cotton material (cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 45%;

[0052] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 56° C. within 25 minutes;

[0053] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 300r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 15kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0054] Example 6

[0055] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0056] Step 1, put the qualified explosive cotton material (the cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 47%;

[0057] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 58° C. within 28 minutes;

[0058] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 330r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 17kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0059] Comparative Example 1:

[0060] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0061] Step 1, put the qualified explosive cotton material (cotton content in water is 10-13%) prepared and analyzed into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 50%;

[0062] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 60° C. within 30 minutes;

[0063] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 330r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 17kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0064] Comparative Example 2:

[0065] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0066] Step 1, put the qualified explosive cotton material (cotton content in water is 10-13%) into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 66%;

[0067] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 55° C. within 30 minutes;

[0068] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 300r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 15kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0069] Comparative Example 3:

[0070] A dehydration method for high-viscosity explosive cotton comprises the following steps:

[0071] Step 1, put the qualified explosive cotton material (cotton content in water is 10-13%) into the concentrator 1, and the liquid level height of the feed tank of the concentrator 1 is 66%;

[0072] Step 2, turn on the concentrator steam heating tube 2 to heat the material in the feed tank to raise its temperature, and raise the temperature of the material to 50° C. within 1 hour;

[0073] Step 3, turn on the cotton material delivery pump 3 and the dehydration centrifuge 5, the rotation speed of the cotton material delivery pump 3 is set to 290r / min, at this time, the material discharge speed in the dehydration centrifuge 5 is 14kg / min, and the finished product is discharged from the centrifugal discharge pipe of the dehydration centrifuge 5.

[0074] The finished products of the above-mentioned embodiments 1-6 and comparative examples 1-3 were sampled, and the moisture content of the finished products was analyzed using an oven method. The viscosity of the explosive cotton material before and after dehydration was analyzed using a WJ-2006 rolling ball viscometer. The results are shown in Table 1 below.

[0075] Table 1

[0076]

[0077]

[0078] The test results show that after using the method of the present invention, the dehydration moisture of high-viscosity explosive cotton can reach 32-34% at one time, ensuring that the moisture and viscosity are qualified at one time. The viscosity decreases slightly after dehydration, at 24-29%, compared with the traditional method, which is 35-40%. The present invention greatly reduces the effect of the viscosity of the product. At the same time, the dehydration output is increased from 12-14kg / min to 15-17kg / min, and the production efficiency is improved.

[0079] The invention solves the conflicting problem that cotton material is easy to dehydrate at high temperature and viscosity is easily damaged at high temperature: in order to ensure the qualified moisture content of finished products, cotton material must be heated and the heating temperature exceeds 50-55°C of the original conventional process and is required to reach 56-60°C; the viscosity of cotton material is related to temperature and heating time, and the longer the residence time is in a high temperature environment, the greater the reduction of cotton material viscosity; the existing concentrator generally has a dehydration time of about 1 hour, and the volume liquid level is 2 / 3 of the concentrator; the invention shortens the liquid level height of the concentrator, reduces the liquid level from 2 / 3 to 1 / 2, and simultaneously improves the cotton material heating speed of the concentrator, shortens the heating time, and reduces the original 1-hour dehydration time to 30 minutes, that is, the residence time of cotton material under the condition of 56-60°C is reduced by half an hour, and the damage of viscosity caused by long heating time is slowed down; in addition, the invention also increases the feed amount of the cotton material conveying pump, accelerates dehydration, and reduces the residence time of cotton material in the concentrator, and further slows down the damage of viscosity at a higher temperature. The feed amount of the cotton material conveying pump is controlled by the speed, increasing the original speed of 280-290r / min to the current speed of 300-330r / min.

[0080] The present invention adopts high-temperature rapid dehydration to replace the traditional low-temperature and slow dehydration, and reduces the residence time of the material at high temperature in the concentrator by lowering the feed liquid level and reducing the time for the material to heat up, thereby reducing the influence of the longer heating time on the viscosity.

Claims

1. A method for dehydrating high-viscosity explosive cotton, characterized in that: The following steps are involved: Step 1, adding explosive cotton to the concentrator, the cotton material liquid level height is 45-55% of the height of the concentrator feed tank; Step 2, heating the explosive cotton material to 56-60°C within 25-30 minutes; Step 3, conveying the heated exploded cotton material to a dehydration centrifuge for dehydration.

2. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: The cotton concentration of the collodion cotton material in step 1 is 10-13%.

3. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: In step 2, heating is performed using a concentrator steam heating tube.

4. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: The heating in step 2 uses a uniform heating rate.

5. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: The feeding speed in the dehydration centrifuge in step 3 is 15-17 kg / min.

6. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: In the step 3, the dehydration centrifuge 5 is a P60 centrifuge.

7. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: The heated explosive cotton material in step 3 is transported through a cotton material transport pump.

8. The dehydration method of high-viscosity explosive cotton according to claim 7, characterized in that: The rotation speed of the cotton material conveying pump is 300-330r / min.

9. The dehydration method of high viscosity explosive cotton according to claim 1, characterized in that: The cotton material liquid level height is 50% of the height of the concentrator feed tank, and the explosive cotton material is heated to 58° C. within 30 minutes.

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