流化床干燥器

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流化床干燥器

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流化床干燥机(又称流化床干燥机)是制药工业中广泛使用的一种降低药粉、颗粒含水率的设备。该设备的工作原理是原料流化。

在流态化过程中,热空气在高压下通过湿固体颗粒的多孔床层引入。湿固体从底部被提起,悬浮在空气流中(流态化)。热传递是通过湿固体和热气体之间的直接接触来实现的。蒸发的液体被干燥的气体带走。有时为了节约能源,出口的气体会被部分回收。

一个典型的流化床干燥器由以下组件组成

a.空气准备单元。

b。产品容器。

c。排气过滤器。

d。排风机。

e。控制面板。

f.配风板。

G。喷嘴。H。解决方案交付。期间使用的分配器的选择和干燥过程除了确保均匀和稳定的流化还防止在某些区域的固体的1普尔流化质量在流化床干燥器。2.堵塞分配器的-perforated孔。3.从落入风箱或位于流化床下方气体室的固体。在整个经销商的压降必须足够高,以保证良好的和均匀的流动。目录[显示]参数到在流化床干燥器(系统)为了改进操作,效率,和流化床干燥器的再现控制,一些参数需要被控制。这些参数被分为:设备参数:那些由设备控制。 Process parameters: Those controlled by the process. Product parameters: Those controlled by the product. 1. Apparatus/Equipment Parameter Position of the air distribution plate: This parameter influences the pattern. Shape of the instrument: The annular based design gives a better product. Nozzle height: Nozzle height plays a vital role when fluidized bed dryers are used as a coating machine. The atomized coating solution should not get dried before reaching the tablet surface. 2. Process/Operating Parameter Temperature: Increased temperature leads to increased moisture diffusivity and hence increased drying rate and decreased drying time. The nature of the material plays an important role in choosing the operating temperature. Humidity: Faster drying is achieved when the moisture content of the inlet air is maintained at its minimum. Airflow rate/gas velocity: Increasing gas velocity increases drying rate but should be maintained at an optimized rate (not to fast or too slow). Gas velocity has no effect on particles with high internal resistance to moisture transfer. 3. Product Parameters Moisture content of the feed material. Feed rate/batch size. Product moisture content. Particle size, shape, and diameter. Read Also: Rotary Dryer Types of Fluidized-Bed Dryers There are various types of fluidized bed dryer and an individual’s familiarity with the specific characteristics of these various types enables one to make a logical and cost-effective selection of fluidized bed dryer for a drying operation. In many instances, several different types may provide similar performance at the same cost. It should be noted also that not all modified fluidized bed dryers are necessarily better than the conventional dryers in terms of product quality, or energy efficiency, or drug performance. picture of conventional fluid bed dryers 1. Conventional Fluidized Bed Dryers Conventional fluidized bed dryers include; Batch fluidized bed dryers. Semi-continuous fluidized bed dryers. Well-mixed, continuous fluidized dryers. Plug flow fluidized bed dryer. 2. Modified Fluidized Bed Dryers Various types of modified fluidized bed dryers have been developed and are applied in many industrial processes to overcome some of the problems encountered while using conventional fluidized bed dryers for a drying process. They include but not limited to; Hybrid fluidized bed dryers Pulsating fluidized bed dryers Fluidized bed dryer with immersed heat exchange. Mechanically assisted fluidized bed dryer. Vibrated fluidized bed dryer. Agitated fluidized bed dryer/swirl fluidizers. Fluidized bed dryers of inert particles. Spouted bed dryer. Recirculating fluidized bed dryer. Jetting fluidized bed dryer. Superheated steam fluidized bed dryer. Fluidized bed freeze dryer. Heat pump fluidized dryers. It should be noted that not all modified fluidized bed dryers are necessarily better than the conventional dryers in terms of product quality, or energy efficiency, or drying performance. Advantages of Fluidized-bed Dryers 1. High rates of moisture removal due to excellent gas-particle constant which results in high heat and mass transfer rates. 2. High thermal efficiency is usually achieved if part of the thermal energy for drying is supplied by the internal heat exchanger 3. Lower capital and maintenance cost 4. Reduced contact time for drying. 5. Ease of control. Disadvantages of Fluidized Dryers 1. High pressure drops results as a result of the need to suspend the entire bed in gas which equally leads to high energy consumption. 2. Requires increased gas handling due to extensive recirculation of exhaust gas for high thermal efficiency operation. 3. Poor fluidization and low flexibility especially if the feed is too wet. 4. Not the best choice of equipment when organic solvents need to be removed during drying. 5. Non-uniform product quality for certain types of fluidized bed dryers. 6. Entertainment of fine particles. 7. High potential for attrition; and in some cases agglomeration of fine particles. 8. The conventional hot air fluidized bed dryers are not a good choice of dryer when handling toxic or flammable solids since there is danger of fire or explosion of flammability limits are exceeded.

参考Arun S. Mujumdar(2015)。工业干燥手册。CRC出版社,泰勒和弗朗西斯集团,纽约。

标签:烘干机,流体床烘干机,fbd烘干机