A major Middle Eastern export refinery on the Red Sea recently increased refining capacity that required the addition of two large amine loops for sulfur recovery. The filtration of solids coming from the amine loops, mainly FeS agglomerates, pipe scale and degradation products can be one of the most difficult filter applications in refinery operations, as the solids form impervious layers that will smear off any filter material.
The Dahlmam Terraced Filter Technology selected by the refiner and Korean contractor had been developed in cooperation between Shell and Dahlman. According to Dahlman, the advantage of these filters for this amine application are that one filter equals or replaces 36 pcs string wound cartridges; operator involvement is significantly reduced; low OPEX and short downtimes; filtration from inside to outside minimizes risk from environmental pollution during element change-outs; extensive pilot plant and commercial data base optimizes operating conditions; coreless construction elements are fully incinerable; unique Quick O-ring sealing device assures filtration integrity and super fast change-out times;
filter is completely drainable and there is negligible product loss; specially developed needle felt filter material combines surface and depth filtration.
Cartridge type filters have been traditionally selected for this application. However, from Dahlman’s point of view, cartridge filters means filters based on replaceable disposable filter elements. The dirt is settled in or outside these elements. If the pressure drop is too high the elements have to be replaced with new ones. The Dahlman terraced filters are also based on replaceable disposable elements but designed in a way that has more advantages compared to “normal cartridge filters.” In fact, it is an improvement of the standard technology.