Sorption-enhanced methanol steam reforming for hydrogen production by combined copper-based catalysts with hydrotalcites

Abstract

Hydrogen is stored in liquid methanol to ensure safe transportation, and when needed, hydrogen is produced in situ through methanol steam reforming at a relatively low temperature (about 473 K–573 K), which is considered as a significant breakthrough in the storage and transport system of hydrogen energy. To improve methanol conversion, the process intensification technology, called as sorption enhanced methanol steam reforming, is developed, where the configuration between catalyst and sorbent is investigated experimentally in this work. Catalyst is commercial CuO/ZnO/Al2O3 catalyst, and sorbent is K2CO3 promoted hydrotalcite (K-hydrotalcite). Two kinds of packed modes in the reactor are tested and compared with each other, one packed mode with the mixture of catalyst particles and sorbent particles, and the other packed mode with composite sorbent-catalyst particles pelleted with the mixture of catalyst powders and sorbent powders. According to the experimental results, it is found that CO2 adsorption by K-hydrotalcites enhances significantly methanol steam reforming in both packing modes. When combined CuO/ZnO/Al2O3 catalyst with K-hydrotalcite into one-body composite pellet, the methanol conversion reduces due to the loss of catalytic activities under the alkaline atmosphere of K-hydrotalcites. Therefore, attention should be paid on the synergic relationship between catalysts and sorbents for sorption enhanced reaction.