Introduction of RPB for process intensification

“PI technology was invented in the late 1970s and early 1980s. RPB, a typical PI equipment, was invented by Ramshaw and Mallinson (1981) for enhancing the gas–liquid mass transfer in distillation and absorption processes. The technology promotes size and weight reduction, enhances inherent safety with lower inventories, improves energy consumption, lower capital cost, and addresses environmental concerns (Jassim et al., 2007). With RPB, intensification is achieved by rotation of the equipment during operation. The associated centrifugal acceleration leads to droplet flow and film flow of liquids in the unit. This will increase interfacial area and consequently mass transfer. Based on this, vessel size will therefore be reduced significantly compared to conventional absorbers (Jassim et al., 2007Wang et al., 2011Cheng and Tan, 2011).

Trevor (1998) reported that one of the ways to get friendliness in plant design can be achieved by the use of intensification. He defined friendliness in a plant as the existence of low inventory of hazardous materials such that it may not matter if the entire inventory leaks.

The absorber rig using RPB is shown in Fig. 1. Flue gas is passed through the stainless steel shaft to the packed bed and it is contacted counter-currently with lean-MEA solution. MEA chemically absorbs CO2 in the flue gas leaving the treated gas with lower CO2 content. The treated gas is vented into the environment. The rich MEA solution stream is sent to a stripper for regeneration of the lean MEA solution.

Fig. 1. Cross-sectional view of the HIGEE rig (Jassim et al., 2007).

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