Method for operating a methanation reactor

Operating a methanization reactor, comprises methanizing a reactant gas containing carbon dioxide and hydrogen in a first operating mode, along a flow path of the reactor with a first catalytic conversion rate to produce a methane-rich product gas (2), and guiding a methane-rich gas stream at least at the beginning of the flow path in a second operating mode with a lower or negligible second conversion rate. Independent claims are also included for: (1) methanization reactor, preferably for carrying out the above method, comprising (i) a first supply device (10) for reactant gas containing carbon dioxide and hydrogen, at the flow path of the reactor, along which a catalyst is arranged, (ii) a dispenser for dispensing the methane-rich product gas along the flow path produced by the catalytic methanation of the feed gas, (iii) a control device (30), and (iv) a second supply device for supplying the methane-rich gas mixture to the beginning of the flow path, where the control device is switched between the first operating mode, where the product gas is produced in the first conversion rate, and the second operating mode, where the methane-rich gas stream flows at least at the beginning of the flow path with the lower or negligible conversion rate; and (2) an assembly of the methanization reactor, and an electrolyzer (20) for electrolytic production of hydrogen for the reactant gas. Die Erfindung betrifft ein Verfahren zum Betreiben eines Methanisierungsreaktors, bei dem in einer ersten Betriebsart ein Kohlendioxid und Wasserstoff aufweisendes Eduktgas entlang eines Strömungsweges des Reaktors mit einem ersten Stoffumsatz katalytisch zu einem methanreichen Produktgas methanisiert wird, wobei man wenigstens am Beginn des Strömungsweges in einer zweiten Betriebsart mit geringerem oder verschwindendem zweiten Stoffumsatz einen methanreichen Gasstrom strömen läßt, und eine mit diesem Verfahren betreibbare Anlage.