The dichloroethane double cone rotary vacuum dryer is a drying device that integrates mixing and vacuum drying. The process of vacuum drying is to place the material to be dried in a sealed cylinder, and vacuum the vacuum system to continuously heat the material to be dried, so that the moisture inside the material diffuses to the surface through pressure difference or concentration difference, water molecules (or other The non-condensable gas) obtains sufficient kinetic energy on the surface of the material, diffuses into the low pressure space of the vacuum chamber after overcoming the mutual attraction between the molecules, and is evacuated by the vacuum pump to complete the separation from the solid. Therefore, the dichloroethane double cone rotary vacuum dryer exhibits the following characteristics:
(1) During the vacuum drying process, the pressure in the cylinder is always lower than the atmospheric pressure, the number of gas molecules is small, the density is low, and the oxygen content is low, so that the medicine which is easy to oxidize can be dried, and the chance of contamination of the material is reduced.
(2) Since the moisture content is proportional to the steam pressure during the vaporization process, the moisture content in the material can be vaporized at a low temperature during vacuum drying to achieve low temperature drying, and is particularly suitable for the production of a drug having heat sensitive materials.
(3) Vacuum drying can eliminate the surface hardening phenomenon easily caused by atmospheric hot air drying. This is because the pressure difference between the vacuum drying material and the surface is large. Under the pressure gradient, the moisture quickly moves to the surface without surface. hardening.
(4) Due to the small temperature gradient between the inside and outside of the material during vacuum drying, the moisture can be moved and collected by itself due to the reverse osmosis, effectively overcoming the dispersion caused by hot air drying.
The apex angle of the product parameters of the dichloroethane double-cone rotary vacuum dryer is 90°～60° (depending on the angle of repose of the material), and the filling rate of the material is 30%-50%. The speed of the equipment is generally determined by N ≤ 42.3D?r/min (D is the large swing diameter of zui). The heat transfer coefficient U of the jacket is independent of the operating pressure, U=116～140W/(m?·K) for the non-bonded material, U=80～93W/(m?·K) for the bonding material. The heat transfer area is based on the area of ​​the material contacting the cylinder wall. The cylinder of the dryer is designed according to the pressure vessel, the inner cylinder is subjected to external pressure, and the outer cylinder is subjected to internal pressure.
The selection of products can be produced in many domestic factories. This kind of dryer is mainly used to select some problems that should be paid attention to.
Characteristics of the material 1) Viscosity of the material. The viscosity of the material changes with its moisture content. The viscosity allows the material to agglomerate into pieces and adhere to the wall of the cylinder. After drying, it tends to adhere to the dust collector and the pipe wall. Pneumatic vibration and crushing devices can be used.
2) Allowable temperature of the material. The allowable temperature is the high temperature at which the material can withstand. Exceeding this temperature will result in a change in material potency, decomposition or discoloration.
3) Bulk density of material The mass of material per unit volume is called the bulk density. Since the material is a mixture of the dry material and the moisture, the dry material tends to be a granular, powdery or solid material, and the gap between the dry material particles varies with the moisture content in the material. There is a big difference in the bulk density of the raw wet material and the drying process. Care should be taken when selecting the dryer.
4) When stacking granular or powdery materials at the slip angle of the material, when the angle between the inclined surface of the material pile and the bottom surface increases to a certain angle, the side material will slide down. The angle between the slope of the material falling off and the bottom surface is called the slip angle of the material. The slip angle is related to material composition, moisture content, particle size and viscosity. When selecting a double cone dryer, you can select the angle of the cone by referring to the slip angle of the material.
The drying temperature varies depending on the physical properties of the material, and an appropriate temperature can be selected. Generally, a variable temperature drying method can be selected, and the temperature is low at the initial stage of drying, and the temperature is gradually increased to increase the drying rate.
When the vacuum is started and heated, the drying speed is slow. When the material is heated above the vaporization temperature of the water, the drying speed will suddenly increase, and the material will be heated to the vaporization temperature under the corresponding pressure within the allowable temperature range and vaporized in a large amount. The temperature remains unchanged, the added heat is used for the heat of vaporization and various heat losses, and the vacuum system continuously discharges the vaporized vapor to maintain the pressure difference between the evaporation surface and the space, so that the drying continues. The moisture content of the material is reduced to a certain extent, and the water evaporated from the material is reduced. When the heating amount is constant, the temperature of the material begins to rise, the pressure difference between the evaporation surface and the space decreases, and the drying shifts into the deceleration phase. The drying speed gradually decreases until it reaches zero.
The working vacuum is usually 10?~10?Pa. The vacuum is high, the moisture vaporization temperature in the material is low, and the drying speed is fast. However, the vacuum is too high, which leads to an increase in the cost of the pumping system, and the price of the material after drying increases, which is economically uneconomical.
Although the rotation speed of the cylinder is faster, the drying speed is higher. However, in the early stage of drying, if the rotation speed is faster, it is easy to cause the material to stick to agglomerate. Therefore, a lower rotation speed is used in the initial stage of drying, and the rotation speed of the cylinder is increased when the surface of the material is dry. In the later stage of drying, as the water content of the material decreases, the rotation speed should also be appropriately reduced. At this time, increasing the rotation speed is not beneficial to the improvement of the drying speed. Therefore, the staff should be regulated at any time according to the material conditions during the drying process.
Influencing factors (1) The condition of the material to be dried (such as material shape, size, stacking method), the moisture content, density, viscosity and other properties of the material itself. In addition, if the method is adopted to increase the initial temperature of the material, pre-treatment by vacuum filtration, and reduce the moisture content of the material, the vacuum drying speed can be increased.
Bulk density of material: The bulk density of a material refers to the mass of material per unit volume. Since the material is a mixture of the dry material and the moisture, the dry material is often in the form of granules or powder, and the gap between the particles of the dry material is different due to the difference in moisture content in the material. Therefore, the bulk density of the raw wet materials and the drying process are also very different, which is especially important in the preparation of raw materials.
Allowable temperature of the material: The allowable temperature is the high temperature of the material that the material can withstand. Exceeding this temperature will cause the material to change, decompose or discolor. Thermosensitive drugs can generally be used around ≤60 °C.
Viscosity of the material: The viscosity of the material changes with the moisture content. The viscosity allows the material to agglomerate into pieces and adhere to the wall of the cylinder. After drying, it tends to adhere to the dust collector and the tube. In order to solve this problem, Jiangsu Zhifang Drying Equipment Co., Ltd. has recently developed a suspension type using a pneumatic vibrating and crushing device.
Slip angle of material: When stacking granular or powdery materials, when the material pile is inclined and the angle between the bottom and the bottom surface increases to a certain angle, the side material will fall down. The angle at which the material slips and the angle to the bottom refers to the slip angle of the material. The slip angle is related to material composition, moisture content, particle size and viscosity. Therefore, when designing and selecting, the angle of the double cone of the cylinder should be selected according to the slip angle of the material.
The higher the degree of vacuum, the more favorable the vaporization of water at lower temperatures, but the higher the degree of vacuum is not conducive to heat conduction, affecting the heating effect on the material. In order to improve the drying speed of the material, the degree of vacuum should be considered comprehensively according to the characteristics of the material. Generally, the degree of vacuum should not be less than 10?Pa.
Operation procedure of double cone rotary vacuum drying in the south 1. Check before driving: a. Turn on the vacuum pump to check whether the pipe joint and the stuffing box are leaking, whether the inlet and outlet ports are sealed well, and whether the vacuum gauge reaction is sensitive. b. Open the cooling water valve to check the connection of the heat transfer pipe, whether the stuffing box leaks, and whether the pressure gauge reaction is sensitive. c. Check whether the instruments, buttons and indicators of the electric control cabinet are normal, check whether the grounding wire is good, whether there is leakage or not, and the short circuit exists. d. Fill the oil cup with grease, start the motor running, and listen to the noise. If it is not normal, check the source of noise and eliminate it.
2. Add the dry material to the container (powder, fine granular, slurry material using vacuum feed), then close the feed hole cover. 3. After closing the vacuum valve, open the vacuum pump to make the dry container under negative pressure (600 – 755 mmHg).
4. Close the power switch, start the motor, press the work button, and the dryer starts to rotate.
5. Open the heat carrier valve, let the heat carrier enter the sandwich of the dry container, and test according to the process requirements.
6. After the material is dried, first close the heat carrier valve, then inject cooling water into the interlayer. After the material is cooled to normal temperature, stop vacuuming. Open the vacuum valve, turn off the motor, stop the dryer from rotating, and open the hole cover to discharge.
This machine is suitable for vacuum drying and mixing of powder and granular materials in the pharmaceutical, food, chemical and other industries. It is especially suitable for materials with the following requirements:
1, can not accept high-temperature heat-sensitive materials; 2, easy to oxidize, hazardous materials; 3, the need to recover solvents and toxic gases; 4, requires a minimum of volatile volatile materials; 5, requires adequate mixing, uniform materials.
Changzhou City Drying Equipment Co., Ltd. provides annual spot supply, 300 liters, 500 liters, and 1000 liters.
It is a drying equipment that integrates mixing and vacuum drying. The process of vacuum drying is to place the material to be dried in a sealed cylinder, and vacuum the vacuum system to continuously heat the material to be dried, so that the moisture inside the material diffuses to the surface through pressure difference or concentration difference, water molecules (or other The non-condensable gas) obtains sufficient kinetic energy on the surface of the material, diffuses into the low pressure space of the vacuum chamber after overcoming the mutual attraction between the molecules, and is evacuated by the vacuum pump to complete the separation from the solid. So, the performance is as follows:
(1) During the vacuum drying process, the pressure in the cylinder is always lower than the atmospheric pressure, the number of gas molecules is small, the density is low, and the oxygen content is low, so that the medicine which is easy to oxidize can be dried, and the chance of contamination of the material is reduced.
(2) Since the moisture content is proportional to the steam pressure during the vaporization process, the moisture content in the material can be vaporized at a low temperature during vacuum drying to achieve low temperature drying, and is particularly suitable for the production of a drug having heat sensitive materials.
(3) Vacuum drying can eliminate the surface hardening phenomenon easily caused by atmospheric hot air drying. This is because the pressure difference between the vacuum drying material and the surface is large. Under the pressure gradient, the moisture quickly moves to the surface without surface. hardening.
(4) Due to the small temperature gradient between the inside and outside of the material during vacuum drying, the moisture can be moved and collected by itself due to the reverse osmosis, effectively overcoming the dispersion caused by hot air drying.
The apex angle of the product parameters is 90° to 60° (depending on the angle of repose of the material), and the filling rate of the material is 30% to 50%. The speed of the equipment is generally determined by N ≤ 42.3D?r/min (D is the large swing diameter of zui). The heat transfer coefficient U of the jacket is independent of the operating pressure, U=116～140W/(m?·K) for the non-bonded material, U=80～93W/(m?·K) for the bonding material. The heat transfer area is based on the area of ​​the material contacting the cylinder wall. The cylinder of the dryer is designed according to the pressure vessel, the inner cylinder is subjected to external pressure, and the outer cylinder is subjected to internal pressure.
The selection of products can be produced in many domestic factories. This kind of dryer is mainly used to select some problems that should be paid attention to.
Characteristics of the material 1) Viscosity of the material. The viscosity of the material changes with its moisture content. The viscosity allows the material to agglomerate into pieces and adhere to the wall of the cylinder. After drying, it tends to adhere to the dust collector and the pipe wall. Pneumatic vibration and crushing devices can be used.
2) Allowable temperature of the material. The allowable temperature is the high temperature at which the material can withstand. Exceeding this temperature will result in a change in material potency, decomposition or discoloration.
3) Bulk density of material The mass of material per unit volume is called the bulk density. Since the material is a mixture of the dry material and the moisture, the dry material tends to be a granular, powdery or solid material, and the gap between the dry material particles varies with the moisture content in the material. There is a big difference in the bulk density of the raw wet material and the drying process. Care should be taken when selecting the dryer.
4) When stacking granular or powdery materials at the slip angle of the material, when the angle between the inclined surface of the material pile and the bottom surface increases to a certain angle, the side material will slide down. The angle between the slope of the material falling off and the bottom surface is called the slip angle of the material. The slip angle is related to material composition, moisture content, particle size and viscosity. When selecting a double cone dryer, you can select the angle of the cone by referring to the slip angle of the material.
The drying temperature varies depending on the physical properties of the material, and an appropriate temperature can be selected. Generally, a variable temperature drying method can be selected, and the temperature is low at the initial stage of drying, and the temperature is gradually increased to increase the drying rate.
When the vacuum is started and heated, the drying speed is slow. When the material is heated above the vaporization temperature of the water, the drying speed will suddenly increase, and the material will be heated to the vaporization temperature under the corresponding pressure within the allowable temperature range and vaporized in a large amount. The temperature remains unchanged, the added heat is used for the heat of vaporization and various heat losses, and the vacuum system continuously discharges the vaporized vapor to maintain the pressure difference between the evaporation surface and the space, so that the drying continues. The moisture content of the material is reduced to a certain extent, and the water evaporated from the material is reduced. When the heating amount is constant, the temperature of the material begins to rise, the pressure difference between the evaporation surface and the space decreases, and the drying shifts into the deceleration phase. The drying speed gradually decreases until it reaches zero.
The working vacuum is usually 10?~10?Pa. The vacuum is high, the moisture vaporization temperature in the material is low, and the drying speed is fast. However, the vacuum is too high, which leads to an increase in the cost of the pumping system, and the price of the material after drying increases, which is economically uneconomical.
Although the rotation speed of the cylinder is faster, the drying speed is higher. However, in the early stage of drying, if the rotation speed is faster, it is easy to cause the material to stick to agglomerate. Therefore, a lower rotation speed is used in the initial stage of drying, and the rotation speed of the cylinder is increased when the surface of the material is dry. In the later stage of drying, as the water content of the material decreases, the rotation speed should also be appropriately reduced. At this time, increasing the rotation speed is not beneficial to the improvement of the drying speed. Therefore, the staff should be regulated at any time according to the material conditions during the drying process.
Influencing factors (1) The condition of the material to be dried (such as material shape, size, stacking method), the moisture content, density, viscosity and other properties of the material itself. In addition, if the method is adopted to increase the initial temperature of the material, pre-treatment by vacuum filtration, and reduce the moisture content of the material, the vacuum drying speed can be increased.
Bulk density of material: The bulk density of a material refers to the mass of material per unit volume. Since the material is a mixture of the dry material and the moisture, the dry material is often in the form of granules or powder, and the gap between the particles of the dry material is different due to the difference in moisture content in the material. Therefore, the bulk density of the raw wet materials and the drying process are also very different, which is especially important in the preparation of raw materials.
Allowable temperature of the material: The allowable temperature is the high temperature of the material that the material can withstand. Exceeding this temperature will cause the material to change, decompose or discolor. Thermosensitive drugs can generally be used around ≤60 °C.
Viscosity of the material: The viscosity of the material changes with the moisture content. The viscosity allows the material to agglomerate into pieces and adhere to the wall of the cylinder. After drying, it tends to adhere to the dust collector and the tube. In order to solve this problem, Jiangsu Zhifang Drying Equipment Co., Ltd. has recently developed a suspension type using a pneumatic vibrating and crushing device. [1]
Slip angle of material: When stacking granular or powdery materials, when the material pile is inclined and the angle between the bottom and the bottom surface increases to a certain angle, the side material will fall down. The angle at which the material slips and the angle to the bottom refers to the slip angle of the material. The slip angle is related to material composition, moisture content, particle size and viscosity. Therefore, when designing and selecting, the angle of the double cone of the cylinder should be selected according to the slip angle of the material.
2 The higher the degree of vacuum, the more favorable the vaporization of water at a lower temperature, but the higher the degree of vacuum is not conducive to heat conduction, affecting the heating effect on the material. In order to improve the drying speed of the material, the degree of vacuum should be considered comprehensively according to the characteristics of the material. Generally, the degree of vacuum should not be less than 10?Pa.
Operation procedure of double cone rotary vacuum drying in the south 1. Check before driving: a. Turn on the vacuum pump to check whether the pipe joint and the stuffing box are leaking, whether the inlet and outlet ports are sealed well, and whether the vacuum gauge reaction is sensitive. b. Open the cooling water valve to check the connection of the heat transfer pipe, whether the stuffing box leaks, and whether the pressure gauge reaction is sensitive. c. Check whether the instruments, buttons and indicators of the electric control cabinet are normal, check whether the grounding wire is good, whether there is leakage or not, and the short circuit exists. d. Fill the oil cup with grease, start the motor running, and listen to the noise. If it is not normal, check the source of noise and eliminate it.
2. Add the dry material to the container (powder, fine granular, slurry material using vacuum feed), then close the feed hole cover. 3. After closing the vacuum valve, open the vacuum pump to make the dry container under negative pressure (600 – 755 mmHg).
4. Close the power switch, start the motor, press the work button, and the dryer starts to rotate.
5. Open the heat carrier valve, let the heat carrier enter the sandwich of the dry container, and test according to the process requirements.
6. After the material is dried, first close the heat carrier valve, then inject cooling water into the interlayer. After the material is cooled to normal temperature, stop vacuuming. Open the vacuum valve, turn off the motor, stop the dryer from rotating, and open the hole cover to discharge.
This machine is suitable for vacuum drying and mixing of powder and granular materials in the pharmaceutical, food, chemical and other industries. It is especially suitable for materials with the following requirements:
1, can not accept high-temperature heat-sensitive materials; 2, easy to oxidize, hazardous materials; 3, the need to recover solvents and toxic gases; 4, requires a minimum of volatile volatile materials; 5, requires adequate mixing, uniform materials.
Changzhou Feima Drying Equipment Co., Ltd. provides annual stock, 300 liters, 500 liters, 1000 liters.
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