Kellogg Brown Root Advanced Ammonia Process-Plus KAAP

Kellogg Brown Root Advanced Ammonia Process - Plus (KAAP) 

The first application in 1992 used a two-bed, hot-wall KAAP reactor that featured a low pressure drop and radial flow. Because of the KAAP catalyst s high activity, thin beds are necessary to keep operating temperatures within the desired range203. In 2002 the KAAP reactor had evolved to a four-bed design. A magnetite catalyst is used in the first bed of the synthesis loop when the ammonia concentration is below 2% of the feed. Then the ruthenium catalyst is used in the next three beds to bring the ammonia level up to 18% or more215. 

In most radial-flow converters, the upper portion of the bed is sealed with excess, unused catalyst. This design prevents feed gas from by-passing the reaction section when the catalyst settles. The KAAP reactor uses a proprietary sealing system to overcome this problem. This sealing system avoids the catalyst maldistribution that can lead to formation of hot spots in the catalyst bed. The system also allows 100% of the loaded catalyst volume to be utilized for the ammonia conversion reaction203. 

For start-up the KAAP catalyst is loaded in the oxidized state. It is reduced by passing fresh synthesis gas over the catalyst beds and heating them to 300° C203. 

The KAAP catalyst generates a smaller amount of water during reduction because it contains much less metals than conventional iron catalysts. For this reason, the catalyst reduction proceeds swiftly and required 19 hours in one installation. (Iron catalyst reduction usually requires 36 to 48 hours.)203 

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KAAP plus An improved version of KAAP, announced by Kellogg Brown Root in 1999. It combines the features of the KBR Advanced Ammonia Process, the KBR Reforming Exchanger System, and the KBR Purifier technology. The catalyst is the same as that used in KAAP. In 2003, more than 200 large-scale plants were operating or had been contracted. 

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