Pressure Drop Data

The design of any air pollution control device can vary greatly depending on the industrial process conditions. Great consideration should be given to the selection of the style of plastic random packing for a given system. The physical properties of the plastic random packing including it’s size, geometric surface area, packing factor, void space percentage and material of construction will effect the performance of a system. Kempac plastic random packing offers high performance due to its design and is manufactured utilizing high-end resins.

Pressure drop is typically used to specify packed tower capacity and it is the frictional losses through a series of openings and therefore proportional to the gas flow rate. In plastic random packing the openings are randomly sized and located so the pressure drop is due to expansion, contraction and changes in direction. As the liquid flow rate increases, the liquid occupies some of the random packing’s open space resulting in less room for gas flow. For all liquid flow rates, as gas flow rate is raised, a point is reached when the gas velocity begins to interfere with the free drainage of liquid. Liquid will start to accumulate or load the packed bed. The accumulation of liquid reduces the cross-section area available for gas flow and increases pressure drop throughout the system. As the gas rate increases, more liquid builds, until the liquid surface becomes continuous across the top of the plastic random packing. Liquid rate increases with the gas rate. Proper liquid distribution above the packed bed is essential in order to ensure maximum efficiency of your plastic random packing and helps to keep the pressure drop of a system to a minimum. Good wetting of the scrubber packing increases mass
transfer and improves efficiency. The maximum operational capacity refers to the maximum vapor rate that provides normal efficiency of a plastic random packing. Factors that determine the maximum operational capacity include liquid distribution and vapor distribution. Pressure drop is used to specify packed scrubber capacity. Pressure drop varies in small packed scrubbers or scrubbers with a diameter of three feet or less. With plastic scrubber packing, the smaller the tower diameter the lower the pressure drop. The pressure drop also varies depending in the size and geometry of the plastic random packing. For example, the Kempac Tri-pack plastic random packing offers an efficient geometric design, has an excellent surface area to void space ratio, and is offered in three different sizes. The Tri-pack has a unique network of ribs, struts and dip rods which have been proven to give the Tri-pack a distinct advantage in providing excellent wetting qualities and maintaining liquid distribution throughout the packed bed. The Tri-pack offers an optimum surface area to open area ratio which yields excellent mass transfer efficiency and reduced operating cost. The packing factor of a particular plastic tower packing can be considered in evaluating its performance or efficiency in a specific system. The packing factor is an empirical constant determined for each specific style of plastic tower packing. The packing factor along with other factors can be used to predict pressure drop in a packed scrubber as well as the overall efficiency of a system. In addition to manufacturing the Tri-packs plastic random packing, Kemflo also manufactures a plastic pall ring and plastic saddles packing style.

For more information regarding Kemflo’s plastic tower packing products please visit our website at www.kempac-packing.com.