(118c) Development of Membranes for Hydrogen Production From Coal

We are developing dense hydrogen transport membranes (HTMs) for separating hydrogen from product streams generated during coal gasification. Among the various HTMs we developed, membranes made of 50 vol.% Pd with Y₂O₃-stabilized ZrO₂ have been extensively studied. Hydrogen separation with these membranes is nongalvanic (i.e., requires no electrical power), and the hydrogen separated from the feed stream is of high purity, making post-separation purification steps unnecessary. Using various feed gas mixtures, we measured the hydrogen permeation rate for the membranes in the temperature range of 400-900°C. This rate varied linearly with the inverse of membrane thickness and reached ≈26 and ≈50 cm³ [STP]/min-cm² at 400 and 900°C, respectively, for a ≈20-μm-thick membrane supported on porous substrate when 90% H₂ at ambient pressure was used as the feed gas. The long-term chemical stability of these membranes has been measured under various simulated coal gases and temperatures. We are also developing non-precious metallic membranes that have the potential to meet DOE flux and cost targets at 350°C. The present status of membrane development will be presented in this talk.