FG boiling dryer uses hot air flow to suspend wet particles, fluidized boiling makes heat exchange of materials, and carries evaporating water or organic dissolved coal away through hot air. It uses hot air flow to carry out gas-solid two-phase suspension contact of mass and heat transfer to achieve the purpose of drying wet particles. Fluidized bed drying technology involves two mutual processes of heat transfer and mass transfer. In the process of convection drying, hot air transfers heat energy to the surface of the material through contact with the wet material, and then transfers heat from the surface to the inside of the material, which is a heat transfer process. After the wet material is heated, the surface water is first vaporized, and most of the water is diffused to the surface of the material in liquid or gaseous form, and is continuously vaporized into the air, so that the water of the material is gradually reduced, and the drying is completed, which is a mass transfer process.
FG boiling in the dryer air distribution plate has two functions, one is to support the material layer, the other is to make the gas distribution uniform. The size, shape, distribution situation and opening rate of the distribution plate all play a crucial role in the distribution of fluid. The uneven distribution of gas will make the circulation in the bed, which is more than easy to make some parts of the bed appear "ditch flow", while the rest of the bed is dead, then most of the gas along some channels in the bed in the form of ditch flow short circuit through the bed to leave, so that the gas-solid contact is greatly worsened, which should be avoided, good distribution plate design, It should be able to inhibit the non-uniformity in the bed, that is, when the pressure drop is reduced in some parts of the bed and the airflow speed is increased, the resistance generated by the distribution plate should be able to inhibit the increase of the airflow, thus inhibiting the deterioration of the fluidization.
The extraction port of hot air is generally installed in the auxiliary room, and the heating device and noise reduction device are installed together. The auxiliary room and the clean area are not provided with direct doors and Windows, and the air in the auxiliary room is clean. The net level is often relatively low, which will affect the quality of medicinal hot air, which requires the equipment itself to have a good purification device, otherwise the unpurified air will pollute the drug, it is difficult to meet the GMP requirements, at present, many domestic equipment on the air treatment unit configuration is: effective filter, medium effect filter, steam heating (or electric heating), filter, Although the air treatment system is equipped with primary, middle and filter, but with the continuous increase of running time, the filter will be blocked or damaged, at present, it can only be judged by the appearance of the sign to replace, the lack of theoretical basis, early replacement will increase the cost, and the replacement will bring the risk of air quality peak, thus affecting the quality of the product.
Suggestion: Add the differential pressure display device before and after the filter, when the differential pressure reaches a certain value, the alarm prompts replacement.
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