Fuel processor and method for generating hydrogen rich gas

Fuel processor for generating hydrogen rich gas from hydrocarbon fuel comprising

• an inner housing and an outer housing defining a mantel space between them and at least one fuel reformer unit for reforming hydrocarbon fuel to hydrogen rich gas arranged in the inner housing,
• a fuel processor inlet for introducing hydrocarbon fuel into the inner housing arranged at a first side of the inner housing and a fuel processor outlet for releasing hydrogen rich gas from the inner housing arranged at a second side of the inner housing opposite the first side,
• the outer housing further comprising an air inlet for introducing air into the mantel space,
• the inner housing comprising at least one opening for providing a fluid-connection between the inner housing and the mantel space, and
• at least a first valve device connected to the fuel processor outlet and adapted to direct the flow of the air in the fuel processor from the air inlet through the at least one opening to the fuel processor outlet or vice versa from the fuel processor outlet through the at least one opening to the air inlet.