Fig. 2: Scheme of sustained release of hydrogen via KES and selective extraction to promote the production of extra-heavy olefins.
From: Direct synthesis of extra-heavy olefins from carbon monoxide and water
The green arrow represents WGS. The azure arrows represent FTS, containing chain propagation and hydrogenation. The dark violet arrow represents hydrogenation of dissolved olefins. For KES, hydrogen accumulates through WGS and is gradually consumed through FTS. Water by-produced from FTS serves again as reactant of WGS. Hence a relatively high CO/H2 ratio, which thermodynamically favors the production of C12+=, is maintained. Besides, a phase-transfer agent (PEG) with an affinity to olefins extracts olefin intermediates from surfaces of FTS catalysts to inhibit their further hydrogenation.
