highly dependent on the flow of material through it, which in turn is dependent on the packing and how the flow is managed. Electrical tomography may be used to observe the distribution of liquids at different cross sections of the vessel, or indeed the flow pattern throughout the packed column. Depending on the nature of the materials, capacitance or resistance tomography may be used. See also Height of a theoretical plate (HETP) Continuous distillation Kozeny-Carman equation Fluidized bed Industrial Tomography Systems Dixon rings Random column packing Bibliography References Distillation Chemical equipment