What causes the drying efficiency of the boiling dryer to be affected

What causes the drying efficiency of the fluidized bed dryer to be affected? The principle of the fluidized bed dryer is that bulk granular solid materials are added to the fluidized bed dryer by the feeder The filtered clean air is contacted by the solid material heated by the bottom of the blower to form the heat and mass transfer of fluidized gas-solid two-phase The dry matter is discharged from the unloading port, and the exhaust gas is discharged from the high-level fluidized bed storm and the recovered solid powder after filtration So what are the factors that sometimes affect the drying effect of the boiling dryer? Let's introduce it to you If the material is not properly dried from the boiling dryer, check whether there is enough space in the drying bin to provide sufficient and effective drying time In fact, the effective drying time refers to the exposure of dry particles to the appropriate temperature and dew point If the particle's residence time in the bunker is not enough, proper drying will not be obtained Therefore, we should pay attention to the size and shape of particles or broken materials, which will affect the dry matter accumulation density and residence time In the dry gas path, the drying temperature should be at the inlet of this test, in order to compensate the heat loss of the boiling dryer tube The inlet air temperature of this device is low, which may be due to the lack of improper supervision controller and insulation layer, or the failure of heating element, heating contactor, thermocouple or controller In addition, it is also important to monitor the drying temperature of the whole drying process and observe the temperature fluctuation of the desiccant The bent hose or clogged filter can restrict the air flow and affect the performance of the boiling dryer Therefore, if you check the boiling dryer and find no such problem, you are not sure whether there is enough air Here, there is a quick, simple and effective method to detect the sufficient air flow of the boiling dryer, that is, to measure the vertical temperature curve of the material in this dry state It is assumed that the drying time recommended by the material supplier is 4 hours, and the processing capacity of 100 lbs / h = 0.4536 kg (1 lb) Determine if the flow of the boiling dryer is sufficient to measure the drying temperature curve in the bunker, where it is important to pay special attention to the temperature of 4 hours (400 pounds) If the dry tank 400 lbs is inside the temperature reaches the set value, you can say that the gas flow is enough As long as 1 hour, 2 hours of drying book or 3 hours of material is fully heated, it shows that the air flow can not complete the heating and drying of production materials Lack of heating may indicate that productivity, too small oven, or air clogged or damaged hoses due to filters, etc., are also limited Too large volume will also cause problems, not only waste energy, and lead to high return air temperature, desiccant performance damage The return air filter can prevent the contamination of desiccant and the influence of filamentous substances on its hygroscopicity These filters must be kept clean to ensure adequate air flow When dry air comes from the top of the boiling dryer, most of the heat is released When the temperature of desiccant is in the range of 150 ~ 120, the boiling dryer can work effectively If the return air dryer is overheated, its ability to absorb moisture from the dried air will be reduced Check the return air temperature When the return air temperature is high, it may indicate productivity, too large size, or high temperature when the dry material enters the trash, for example, pet crystallization occurs before drying, or only some materials (such as PET) drying temperature is higher than the normal temperature range In order to prevent the return air temperature from becoming higher, as long as the heat exchanger is installed, the return air can be ensured that the desiccant can effectively remove the moisture in the air and dry The drying speed of the boiling dryer depends on the surface evaporation rate and moisture diffusion rate The drying rate decreases from diffusivity and moisture content, which is called the drying rate decreasing stage In the early stage, the drying rate is usually controlled by the evaporation rate of the surface; then, as long as the external conditions continue to dry, the drying rate and the surface temperature are stable, this stage is called the constant rate drying stage; when the moisture content of the material decreases to a certain extent, the diffusion rate of the water surface decreases, and the specific surface evaporation rate.