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248 Gas PuriJication

separated by internal bypasses which let unfiltered amine solution flow to the next layer. It is
claimed that the multiple layers of filtration media provide 15 times more capacity than a
string-wound cartridge and more than 7 times the capacity of a conventional bag filter
(Anon., 1989). Since one bag filter is equivalent to 15 string-wound cartridge filters, consid-
erable operating labor savings can be achieved during a filter element changeout. Ease of
replacement can enhance operator acceptance, and disposal costs are also often less for bag
filters due to their comparatively smaller volume.
Etched Disk and Sintered Metal Fiber Filters

Either cartridge or bag filters are usually acceptable for small to medium amine systems;
however, larger systems (1,000 gpm or greater amine circulation or more than about 100
LT/day of sulfur production) may require considerable operating labor per filter element
changeout. Operator acceptance of cartridges and bag filters in these larger systems is also
often problematic. For these reasons, some operators of large systems have installed etched
disk or sintered metal fiber filters. Figure 3-25 depicts a fully automated etched disk filter in
a large Canadian gas plant. This 350 gpm filter consists of two parallel filter housings each
containing seven 25-gpm, 10-micron, etched disk elements. These totally automated systems
require little or no operator attention.

Figure 3-25.350-gpm automated Vacco Etched Disc amine filter in a Canadian gas
processing plant. Two 175-gpm filter housings (7 elements per housing) are located on
either side of the control panel. A solution decant tank is to concentrate filtered
particulates located on the right. Courtesy PTl Technologies, Newbury Park, CA