Synthesis gas on demand

A method for rapidly switching a metal-catalysed steam methane reforming reaction of a feed gas comprising hydrocarbons in a reactor system from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice-versa;

• wherein said reactor system comprises a pressure shell housing a structured catalyst arranged to catalyze steam reforming of a feed gas comprising hydrocarbons, said structured catalyst comprising a macroscopic structure of an electrically conductive material, said macroscopic structure supporting a ceramic coating, where said ceramic coating supports a catalytically active material and wherein said reactor system is provided with heat insulation between said structured catalyst and said pressure shell, and where a power supply placed outside said pressure shell is arranged to supply electrical power via electrical conductors connecting to said structured catalyst, allowing an electrical current to run through said macroscopic structure, thereby heating at least part of the structured catalyst;
• said method comprising the steps of:
• in said first steady-state reaction condition (A):
• supplying said feed gas to the reactor system in a first total flow, and
• supplying a first electrical power via electrical conductors connecting an electrical power supply placed outside said pressure shell to said structured catalyst, thereby allowing a first electrical current to run through said electrically conductive material,
• thereby heating at least part of the structured catalyst to a first temperature at which said feed gas is converted to a first product gas mixture over said structured catalyst under said first steady-state reaction conditions (A);
• and said first product gas is outlet from the reactor system;
• and, in said second steady-state reaction condition (B):
• supplying said feed gas to the reactor system in a second total flow,
• supplying a second electrical power via electrical conductors connecting an electrical power supply placed outside said pressure shell to said structured catalyst, thereby allowing a second electrical current to run through said electrically conductive material,
• thereby heating at least part of the structured catalyst to a second temperature;
• at which said feed gas is converted to a second product gas mixture over said structured catalyst under said second steady-state reaction conditions (B);
• and said second product gas is outlet from the reactor system;
• wherein said second electrical power is higher than said first electrical power;
• and/or said second total flow is higher than said first total flow.