Experimental verification of the mercury--iodine thermochemical cycle for the production of hydrogen from water, ANL-4

Conference · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6604091

Appelman, E. H.; Schreiner, F.; Abraham, B. M.

The thermochemical hydrogen-producing cycle ANL-4 consists of the reactions: 2NH/sub 3/ + 2KI + 2CO/sub 2/ + 2H/sub 2/O ..-->.. 2NH/sub 4/I + 2KHCO/sub 3/, 2KHCO/sub 3/ ..-->.. K/sub 2/CO/sub 3/ + CO/sub 2/ + H/sub 2/O, Hg + 2NH/sub 4/I ..-->.. 2NH/sub 3/ + HgI/sub 2/ + H/sub 2/, and HgI/sub 2/ + K/sub 2/CO/sub 3/ ..-->.. 2KI + Hg + CO/sub 2/ + 1/20/sub 2/. The maximum temperature required by the cycle is 1000 K. The calcination reaction is well-known to take place around 475 K and has been described in the literature. The other three reactions have been subjected to experimental verification, and yields and reaction rates have been measured. A flow diagram for the cycle has been constructed, and an overall practical efficiency of 28% in terms of ..delta..G/sub f/(H/sub 2/O)/(total heat input) has been estimated from the new data. A substantial portion of the total heat input is required for the isolation of the ammonium iodide. Our results indicate that the cycle should be capable of producing hydrogen from water with reasonable efficiency and without requiring heat at an unduly high temperature. The cycle should therefore be suitable for a practical demonstration of the technical feasibility of thermochemical hydrogen generation.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6604091
• Report Number(s): CONF-780807-11
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080102* -- Hydrogen-- Production-- Thermochemical Processes
ALKALI METAL COMPOUNDS
CRYOGENIC FLUIDS
DIAGRAMS
EFFICIENCY
ELEMENTS
FLOWSHEETS
FLUIDS
HALIDES
HALOGEN COMPOUNDS
HALOGENS
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
INORGANIC PHOSPHORS
IODIDES
IODINE
IODINE COMPOUNDS
MERCURY
METALS
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
PHOSPHORS
POTASSIUM COMPOUNDS
POTASSIUM IODIDES
PRODUCTION
THERMOCHEMICAL PROCESSES
WATER