CO conversion features

The shift section is designed to maximise the hydrogen output and reduce the CO level in the synthesis gas, thus reducing the inert level in the ammonia synthesis.

The shift section consists of a high temperature shift reactor (HTS) followed by a low temperature shift reactor (LTS).

CO conversion process

The CO conversion section in an ammonia plant is located downstream the secondary reformer.

The performance of the carbonmonoxide (CO) conversion section strongly affects the overall plant energy efficiency, as unconverted carbonmonoxide will consume hydrogen and form CH4 in the methanator, reducing the feedstock and increasing the inert gas level in the synthesis loop.

CO conversion catalysts

The HTS and LTS catalysts convert the carbon monoxide (CO) to carbon dioxide (CO2) and produce more hydrogen. Topsoe's HTS catalyst SK 201 2 is proven in industry to provide exceptional long lifetime due to its high activity and strength. The LTS catalysts LK-821-2 and LK-823 (low temperature shift) are market leaders in the ammonia and hydrogen plant industry.

Topsoe's HTS catalyst SK-201-2 and LTS catalyst system LK-821-2/LK-823 offer the combination of excellent mechanical strength and superior activity and selectivity, which ensures optimal and efficient performance of the shift section.

In addition the SK-201-2 comes with a negligible content of sulphur and hexavalent chromium which makes the initial activation of the catalyst fast and smooth as neither a desulphurisation period nor a reduction procedure for reducing the hexavalent chromium is required.

The LK-823 is a low-methanol catalyst and industrial experience has shown that an eight-fold cut in methanol by-product formation is achieved without any sacrifice of activity or mechanical strength.