High temperature methanation in the long-distance nuclear energy transport system

Abstract

In this review, the general concepts of chemical energy transport processes are discussed. The particular case of the NFE (long-distance energy transport) system, the ADAM and EVE project, is described and results obtained from the ADAM 1 pilot plant and related experiments are reviewed. The methanation pilot plant, ADAM I, fed with about 600 m 3 h −1 (STP) dry synthesis gas from the reformer pilot plant EVA I, has been in operation for 1500 h. In the first adiabatic fixed-bed reactor of the plant, the temperature increase was controlled between 300 and 600°C by product gas recycling during the test run which is described and to between 300 and 700°C in other test runs. The shift of the reaction zone during the operating time of 1500 h was negligible but the length was influenced by changes of gas velocity. Standard activity tests of used catalysts in separate equipment at low temperatures (200–300°C) showed a loss of catalyst activity with respect to methane production compared to the fresh catalyst, but the activity remaining was sufficient for stable operation of ADAM I.