ADIABATIC UT-3 THERMOCHEMICAL PROCESS FOR HYDROGEN-PRODUCTION

The UT-3 thermochemical hydrogen producing cycle is a four step proces s developed at the University of Tokyo. In the process, only solid and gas reactants/products are used and the maximum temperature is 1033 K . In this paper, a new UT-3 process has been developed in which all fo ur reactions are carried out adiabatically using a heat carrier vector (steam or an inert gas). The new process has been evaluated using the ASPEN-PLUS process code. The first law efficiency of the cycle has be en determined as 48.9% and the second law efficiency as 53.2% The proc ess can be realized using conventional materials for the reactors, whi ch can be packed bed, honeycomb or fluidized bed type. In the latter c ase. it is found that the flow rate of the heat carrier fluid is suffi cient to Fluidize all four reactors. For a plant producing 30,000 Nm(3 ) per hour or 2.68 x 10(6) GJ H-2 per year, the plant sizing has been carried out, its operation is discussed and its advantages are present ed. Copyright (C) 1996 International Association for Hydrogen Energy