2设备参数对中药有机溶剂喷雾干燥机粘壁性的影响 喷雾干燥是流化干燥技术用于液体物料的一种较好的方法，其流程是利用雾化器将一定浓度的液体物料喷射成雾状液滴，在干燥的介质中进行热交换使雾状液滴中的溶剂迅速蒸发，获得粉状和颗粒状制品。中药成分因理化性质不同，其传质和传热的速率也存在较大差异，造成不同程度粘壁现象。在充分掌握中药提取物的理化性质的前提下，通过调整喷雾干燥设备的参数可改善粘壁的情况。
2．1 有机溶剂喷雾干燥机喷嘴安装 在喷雾干燥过程中，增加物料的分散度，可加速传热和传质过程。喷嘴的安装对喷雾设备是非常重要的。当雾滴群离开喷嘴时，其形状是个被压缩空气心充满的锥形薄膜，雾滴应均匀分布在喷雾锥中；喷雾锥是对称的，如果不同心就会偏离中心线，进而影响雾化效果，导致雾滴直径增大，严重时会出现液线，造成粘壁现象。因此，在使用的过程中必须保证同心度。
2．2 热风量 风量控制的好坏，zui终体现在干燥物料的含水量，与粘壁有直接的关系。由于喷雾干燥过程是在微负压下操作，雾滴能否达到干燥效果并抽走干燥物料取决于热风量。同时雾滴直径大小可用热风量来调节。随着热风量的增加，雾滴直径减小，干燥加快，粘壁的可能就相对减小。但气流量过大，所得粉体的吸湿性增强，喷雾过程中会发生粘壁现象；气流量过小，导致雾径偏大，干燥不充分，发生粘壁现象。
2．3有机溶剂喷雾干燥机进风温度 进风温度的高低，也是影响粘壁性的主要因素。研究表明：如果在开启设备时就将空气加热器全开，这样就会造成出口温度很快上升，而实际塔体温度并没有均衡升上来．温度不均匀，此时开始喷雾就很容易产生粘壁现象。若温度过高，会对中药有效成分造成破坏或者改变某种成分的性质；温度过低，不能充分干燥，发生粘壁现象。在适宜的范围内，进风温度越高，溶剂蒸发越快，粘壁现象减轻。如果中药浸膏含粘性成分较多，应适当降低进风温度和出风温度，这样就能使喷雾干燥顺利进行，因为糖类成分受高热后粘性增加．则产生粘壁现象，适当降低温度则可减轻粘壁情况。
2．4供液速度 供液速度与粘壁现象的发生也有重要。在其他条件没有改变的情况下，供液速度加快，会导致雾滴未处在流化状态，因干燥不充分而粘于壁上或底部。如提高*微囊的供液速度，虽对其吸湿性的影响不大，但会使其分散率明显下降””。造成雾滴粒径过大，干燥不充分而粘壁。影响喷雾干燥的因素很多，除上述因素外，还存在药液温度、负压大小、负压的稳定性等因素，因此在实际操作中应综合考虑上述影响因素对喷雾干燥工艺的影响。
3 有机溶剂喷雾干燥机关于中药提取物防粘壁的思考 辅料可通过改善物料的吸湿性、提高物料的软化点、增强提取液的流动性、改善提取液的雾化效果、对易吸湿造成粘壁的成分进行包裹等，以发挥其防粘壁作用。因辅料在改善中药提取物性质方面起着重要作用，所以有机溶剂喷雾干燥机喷雾干燥过程中的应用显得尤为重要。对于复方提取物而言，因其理化性质较为复杂，通过单一辅料进行改性所发挥的作用有限．而通过多种辅料联合应用，则可从多方面共同发挥防粘壁作用。对有机溶剂喷雾干燥机，适当提高进风El的温度，可减少粘壁现象的发生。喷雾干燥所用压缩空气的压力应保持恒定，压力的波动会产生严重的粘壁现象。喷嘴进料速度和喷嘴的压缩空气量应匹配，正常操作中应随时检查喷嘴雾化效果，以减少粘壁的发生。但通过调整参数来发挥粘壁作用比辅料的应用所发挥的作用要小，参数的调整范围也很有限。鉴于中药成分的复杂性，在整个喷雾干燥工艺的研究过程中，要充分分析和了解物料的性质，通过辅料的应用和喷雾干燥设备参数的调整，总结防粘壁规律，以解决中药粘壁问题，zui终得到科学、合理、可行的喷雾干燥工艺。
?2 Effect of device parameters on traditional Chinese medicine organic solvent spray dryer wall sticking of spray drying is fluidized drying technology for a better method of liquid material, the process is the use of liquid atomizer to certain concentration of spraying droplets, heat exchange of droplets in the solvent evaporates quickly in the dry the medium for powdery and granular products. Because of the different physical and chemical properties of Chinese medicine, the mass transfer and heat transfer rate also differ greatly, resulting in different degrees of adhesion to the wall. On the premise of fully grasping the physicochemical properties of the extract of traditional Chinese medicine, the conditions of the adhesive wall can be improved by adjusting the parameters of the spray drying equipment.
2.1 the nozzle of the organic solvent spray dryer is installed in the spray drying process, increasing the dispersion of the material, and accelerating the heat transfer and mass transfer process. The installation of the nozzle is very important for the spray equipment. When the droplets from the nozzle, its shape is a compressed air heart with tapered film, droplet should be distributed evenly in the spray cone; the spray cone is symmetrical, if not concentric will deviate from the center line, thereby affecting the atomization effect, cause droplet diameter and liquid line will be serious, caused by wall sticking phenomenon. Therefore, the concentricity must be guaranteed in the process of use.
2.2 the control of the quantity of hot air volume is reflected in the water content of the dry material, which has a direct relationship with the wall of the sticky wall. Because the spray drying process is operated under the micro negative pressure, whether the droplet can reach the drying effect and remove the dry material depends on the amount of hot air. At the same time, the diameter of the droplet can be adjusted by the amount of hot air. As the amount of hot air increases, the droplet diameter decreases, the drying speed increases, and the wall adhesion may be relatively reduced. However, if the gas flow rate is too large, the moisture absorption of the powder will be enhanced, and the sticking phenomenon will occur in the spray process. If the gas flow rate is too small, the fog diameter will be too large and the drying will not be enough.
2.3 the inlet temperature of the air inlet temperature of the organic solvent spray dryer is also the main factor affecting the wall adhesion. Guo Jianbo research shows that if the air heater is fully opened when opening the device, it will cause the outlet temperature to rise rapidly, and the actual tower temperature is not balanced up. The temperature is uneven. At this time, the spray will easily produce sticky walls. If the temperature is too high, it will cause damage to the effective components of Chinese medicine or change the properties of some components; the temperature is too low and can not be fully dried, and the phenomenon of wall sticking occurs. In the suitable range, the higher the air inlet temperature is, the faster the solvent evaporation, the viscosity of the wall is reduced. If the extract of Chinese medicine contains more viscous components, the inlet air temperature and outlet temperature should be reduced appropriay, so that the spray drying can be carried out smoothly, because the carbohydrate components are increased after the high heat viscosity, resulting in sticky wall phenomenon. Decreasing the temperature appropriay can reduce the sticky condition.
2.4 the velocity of feeding liquid supply is also closely related to the phenomenon of wall sticking. When the other conditions are not changed, the speed of the feed is accelerated, which causes the droplets not to be in the flow state and stick to the wall or bottom because of the insufficient drying. as
