Interaction Between Gas-Liquid Jets and Fluidized Beds

在适当的条件下，当一个人通过分布器将加压气体注入小颗粒床中时，就会出现流态化。在流态化床中，颗粒-气体混合物的行为和处理方式就像流体一样--它们可以流动，可以泵送、加热、用于混合或分离层，并且可以连续运行。因此，它们被广泛应用于石油、制药、食品等行业。在许多工业流态化反应器中，如催化裂化装置、涂布机和催化焦化装置，反应物的进料都是以气体喷射或喷雾的形式进入系统，以达到不同的目的。例如，沥青是在流态化焦化过程中喷洒的，通过热裂解的方式来升级沥青。液体沥青和蒸汽通过喷嘴，雾化，水平注入反应堆。液体沥青覆盖在微小的固体颗粒(焦炭)上，发生化学反应产生所需的产品。重要的是要了解喷嘴和喷嘴附近的流态化床中发生的物理现象，以确保涂层均匀，不会发生不希望发生的团聚。当液体喷洒到流态化床中时，通常会发生团聚，形成颗粒团聚，其中的液体被困在其中。在某些过程中，例如在一些制药和食品加工反应器中，它可能是期望的效果，或者在焦化过程中，它可能是不期望的效果。对于所有这些过程，很重要的一点是要很好地了解射流和床层之间的相互作用，以便了解流体的分布、混合、涂层和团聚的形成和破碎。申请者将研究射流-沸腾床相互作用，并将开发描述这一过程的新的数学模型，并加强我们对所涉及的物理现象的理解。该模型在工业上的潜在应用是广泛的，因为它们允许工艺设计和操作改进，以提高反应堆的效率和产量。改进的工艺可以节省能源，减少对环境的影响。

A fluidized bed occurs, under appropriate conditions, when one injects pressurized gas into a bed of small particles through a distributor. In fluidized beds, the particle-gas mixtures behave and can be handled like fluids - they flow, can be pumped, heated, used to mix or separate layers, and can operate continuously. Therefore, they are widely used in the oil, pharmaceutical, food and other industries.In many industrial fluidized bed reactors such as fluid catalytic cracking units, coaters and fluid cokers, the reactant feed is introduced into the system in the form of a gas jet or spray for different purposes. For example, bitumen is sprayed in the fluid coking process, which upgrades bitumen by means of thermal cracking. The liquid bitumen and steam are passed through a nozzle, atomized and injected horizontally into the reactor. The liquid bitumen coats the small solid particles (coke) and chemical reactions occur that produce the desired product. It is important to understand the physical phenomena that occur in the nozzle and in the fluidized bed in the vicinity of the nozzle in order to make sure the coating is uniform and no undesired agglomeration occurs. Agglomeration occurs often when liquid is sprayed into fluidized beds and an agglomerate of particles with liquid trapped inside forms. It can be a desired effect in certain processes, for instance in some pharmaceutical and food processing reactors, or undesirable as in the coking process. For all of these processes, it is important to have a good understanding of the interaction between the jets and the fluidized beds in order to understand the fluid distribution, mixing, coating and agglomerate formation and breakup. The applicant will investigate jet-fluidized bed interaction and will develop novel mathematical models that describe the process and enhance our understanding of the physical phenomena involved. The potential applications of the model to industry are widespread because they allow for process design and operational improvements that enhance the reactor efficiency and increase yield. Improved processes lead to energy savings and less impact on the environment.