Process design and economic analysis of the zinc selenide thermochemical hydrogen cycle

Technical Report · Wed Sep 06 04:00:00 EDT 1978

OSTI ID:6569052

Otsuki, H H; Krikorian, O H

A detailed preliminary design for a hydrogen production plant has been developed based on an improved version of the ZnSe thermochemical cycle for decomposing water. In the latest version of the cycle, ZnCl/sub 2/ is converted directly to ZnO through high temperature steam hydrolysis. This eliminates the need for first converting ZnCl/sub 2/ to ZnSO/sub 4/ and also slightly reduces the overall heat requirement. Moreover, it broadens the temperature range over which prime heat is required and improves the coupling of the cycle with a nuclear reactor heat source. The ZnSe cycle is driven by a very-high-temperature nuclear reactor (VHTR) proposed by Westinghouse that provides a high-temperature (1283 K) helium working gas for process heat and power. The plant is sized to produce 27.3 Mg H/sub 2//h (60,000 lb H/sub 2//h) and requires specially designed equipment to perform the critical reaction steps in the cycle. We have developed conceptual designs for several of the important process steps to make cost estimates, and have obtained a cycle efficiency of about 40% and a hydrogen production cost of about $14/GJ. We believe that the cost is high because input data on reaction rates and equipment lifetimes have been conservatively estimated and the cycle parameters have not been optimized. Nonetheless, this initial analysis serves an important function in delineating areas in the cycle where additional research is needed to increase efficiency and reduce costs in a more advanced version of the cycle.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6569052
• Report Number(s): UCRL-52546
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080102* -- Hydrogen-- Production-- Thermochemical Processes
CHALCOGENIDES
CRYOGENIC FLUIDS
ECONOMIC ANALYSIS
ECONOMICS
ELEMENTS
ENRICHED URANIUM REACTORS
EXPERIMENTAL REACTORS
FLUIDS
GAS COOLED REACTORS
GRAPHITE MODERATED REACTORS
HELIUM COOLED REACTORS
HTGR TYPE REACTORS
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
METALS
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
POWER REACTORS
PROCESS HEAT REACTORS
PRODUCTION
REACTORS
RESEARCH AND TEST REACTORS
SELENIDES
SELENIUM
SELENIUM COMPOUNDS
SEMIMETALS
THERMAL REACTORS
THERMOCHEMICAL PROCESSES
VHTR REACTOR
WATER
ZINC
ZINC COMPOUNDS
ZINC SELENIDES