Position in Process Flow Sheet Direct Recovery

One of the most important initial decisions regarding the adoption of an affinity separation technique in a recovery flow sheet is the selection of the point when that step should occur. Considerations of the expense and fragility of affinity ligands have often resulted in affinity separations being reserved for the later stages of a separation procedure, where, in general, the feedstocks are cleaner and the volume of liquid to be processed is less. Under such circumstances, affinity adsorbents would be expected to be able to be used for more cycles of operation, and each cycle of operation could be conducted in a smaller bed. Both these features would reduce process costs. However, this conservatism often results in under-utilization of the potential resolving power of the affinity separation technique. The possibility of using a highly selective adsorbent for the capture and purification of an adsorbate from a very crude feedstock logically dictates that such a technique should be used at a very early stage in a separation protocol, thus eliminating the need for a series of less selective separation steps, each involving additional expense and a reduction of overall yield. However, the early stages of a separation protocol often involve feedstocks that contain particulates, including whole cells, pieces of broken cells and subcellular structures. The application of such feedstocks directly to packed beds results in the clogging of the bed arising from the capture of the particulates within the bed voids. Such feedstocks are typically pre-clarified by centrifugation or microfiltration, i.e. the use of techniques that not only may have expensive capital and running costs, but also may result in significant reductions in product yields. Recent advances in biochemical engineering have led to the development of a new technique to overcome the need for pre-clarification of the feed before application to an adsorbent bed. Expanded bed adsorption involves the use of beds with greater void volumes created by fluidizing the adsorbent beads in a stable manner as a result of upwards flow of liquid through the bed. Affinity ligands have been used with success in expanded bed adsorption techniques in order to achieve capture, concentration, clarification and purification in a single stage process.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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