An exhaust gas purifying method for a fuel cell vehicle comprises preparing an exhaust gas purifying system for the fuel cell vehicle, the exhaust gas purifying system including a methane removal catalyst for accelerating the conversion of methane into hydrogen and carbon monoxide. The continuous belts are formed of stainless steel each having a width of less than ten inches and grating is provided between the housings permitting personnel to walk over the conveyor system without damaging the stainless steel belts. It comprises an innovative replacement of plates of the \u201cU\u201d type currently used, which do not allow the reversing of the change of direction.