The flagship of the Porocel Claus catalyst line is Maxcel 727, a pure activated alumina product. It has high surface area, good strength, and excellent macroporosity (Table 1). The macroporosity was conferred by a proprietary Porocel technique.
Claus catalysts are mainly used for delivering improved sulfur recovery. They are used as sulfur recovery catalysts in natural gas plants, refineries, and smelters. Claus catalyst must deliver good performance at a variety of process conditions. While the main
task is to convert H2S and SO2 to sulfur, the claus catalyst must also have good activity for conversion of
CS2 and COS. They perform well in facilities that employ Claus process plants, as well as other types of sulfur recovery plants.
Claus catalyst owes its activity to its very high surface area, generally over 300 m2/g for alumina. Over time, the surface area declines due to the adverse effects of temperature and water vapor, and the activity correspondingly declines. For most Claus plants, the rate of surface area loss is quite slow, and the catalysts can be used for years.
Two main types of catalysts are used in conventional Claus units: activated alumina and titania catalysts They vary in their capability to hydrolyze. These Claus catalysts may be used alone or in combination beds, depending upon performance requirements.
The catalyst delivers excellent results when H2S is the primary compound to be removed from the feed gas. Our new-generation activated alumina Claus catalyst, claus catalyst are preferable for use in the first reactor of a typical Claus plant.
CS2 is a side product that forms in the Claus reaction furnace from hydrocarbon contaminants
present in acid gas.1 It is a significant problem in many locations that have relatively high hydrocarbon
concentrations.2 CS2 must be destroyed to maximize sulfur recovery. This is done catalytically
by hydrolysis in the first converter. Since CS2 is difficult to convert, high temperatures are
required to obtain the required reaction rates.
COS forms from CO2, CO, and possibly from conversion of CS2. Although it can be a problem, this
component contains only half as much sulfur as CS2, and is easier to destroy at first converter
conditions. In almost all cases, if CS2 can be satisfactorily reduced, COS will not be an issue. CS2
and COS both form H2S on decomposition.