TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: In the reformer, the heat resistant shield extends in the first direction, and the heat resistant shield is fixed to the surface of the flow path portion facing the combustor at least one point such that the heat resistant shield can expand in the first direction as a result from heat from the combustor. The heat resistant shield is attached to the surface of the flow path portion facing the combustor by at least one spot weld, optionally by a set of spot welds arranged along a line that extends in a circumferential direction around the combustor. The heat resistant shield is formed around the combustor, optionally with a hollow cylindrical shape. The flow path portion is located adjacent the combustor, and the heat resistant shield is located between the flow path portion and the combustor. The flow path portion comprises a first surface and a second surface that extend at least partially in a second direction that intersects with the first direction, the second surface forming an end of the reformer. The flow path portion further comprises a member configured to protect the flow path portion from being distorted by thermal expansion. The member contacts the surface of the flow path portion facing the combustor and the second surface of the connector. The heating unit is arranged to receive and oxidize heating unit fuel and anode off gas. The combustor comprises at least one nozzle arranged to supply the anode off gas to the heating unit chamber in a direction that intersects with the first direction, optionally in a direction perpendicular to the first direction. The heating unit comprises a second combustor arranged to receive and oxidize heating unit fuel. Moreover, the combustor is located at a first end of the heating unit chamber and the second combustor is located at an opposite end of the heating unit chamber. The reforming unit is arranged to reform fuel by a steam reforming reaction in the first space; and/or where the reforming unit is arranged to perform a water gas switching reaction in the second space.