Closed cycle and continuous operation by a thermo-chemical water-splitting IS process

Kubo, Shinji  ; Ohashi, Hirofumi ; Kanagawa, Akihiro; Kasahara, Seiji  ; Imai, Yoshiyuki  ; Fukui, Hiroshi*; Nishibayashi, Toshiki*; Shimazaki, Masanori*; Miyashita, Reiko*; Tago, Yasuhiro*; Onuki, Kaoru

For a stable hydrogen production, essential problems with the closed-cycle operation are declared, and the cycle can ensure these are retained in a steady state in case the H production rate, O production rate and HO supply rate have equivalent values. Process control methods used to maintain the mass balance of the process were devised, involving the installation of accumulators for the total system, techniques to maintain the Bunsen reaction composition and so on. For the plant operation, both controlled and manipulated variables were determined, while computer simulation and the bench scale H production test were used to confirm control methods. For closed cycle operation for water splitting driven by helium gas heat, the method is discussed to allocate heat for the O and H production sections in strict proportion. Finally, the use of computer simulation for the O production system allowed the key to maintaining heat balance within a cascade heat absorption system to be confirmed.