Finally, a comparison between the two technologies catalytic by silver and iron-molybdenum was made, merits of exhaust gas cycling technique for production of formaldehyde were shown significantly.

The paper compares the Lurgi synthesis gas purification technology with that of Linde, in which the cycling solvent methanol has a high water content and consumes considerably.

To prevent this, the wet gas that is produced is often stripped of condensate and the dry gas is reinjected into the reservoir (cycling) to maintain reservoir pressure.