NUCLEAR THERMOCHEMICAL PRODUCTION OF HYDROGEN WITH A LOWER-TEMPERATURE IODINE-WESTINGHOUSE-ISPRA SULFUR PROCESS

摘要

Thermochemical processes are the primary candidates to produce hydrogen (H_2) using high-temperature heat from nuclear reactors. The leading thermochemical processes have the same high-temperature chemical reaction (dissociation of sulphuric acid into H_2O, O_2, and SO_2) and thus all require heat inputs at temperatures of -850℃. The processes differ in that they have different lower-temperature chemical reactions. The high temperatures are at the upper limits of high-temperature nuclear reactor technology. If peak temperatures can be reduced by 100 to 150℃, existing reactor technology can be used to provide the necessary heat for H_2 production and the H_2 produced using nuclear reactors becomes a much more viable near-term industrial option. If process pressures can be increased, significant reductions in capital cost and improvements in efficiency may be possible. The use of inorganic separation membranes is proposed to drive the dissociation reaction to completion at lower temperatures and higher pressures. ORNL has developed a variety of inorganic membranes for commercial applications and has initiated a program to develop a membrane to separate SO_3 from its dissociation products. The basis for using such membranes is described herein. A test loop is being constructed, and membrane testing is expected to be initiated before the end of 2003.