Fuel for fuel cell system

Abstract

A fuel for a fuel cell system comprises wherein said fuel comprises 5 mol. % or more of hydrocarbons, 0.5-20 mass % of oxygenates therein in terms of an oxygen content batsed on the whole fuel and 5 mol. % or less of hydrocarbons having carbon numbers of 2 or less, 90 mol. % or more of hydrocarbons having carbon numbers of 3 and 4 in total, 5 mol. % or less of hydrocarbons having carbon numbers of 5 or more and is a gaseous phase under normal temperature and pressure. The fuel for a fuel cell system has a high power generation quantity per weight, a high power generation quantity per CO 2 emission, a low fuel consumption, a small evaporative gas (evapo-emission), small deterioration of a fuel cell system comprising such as a reforming catalyst, a water gas shift reaction catalyst, a carbon monoxide removal catalyst, fuel cell stacks and the like to maintain the initial performances for a long duration, good handling properties in view of storage stability and inflammability, and a low preheating heat quantity.

1 . A fuel for use in a fuel cell system, wherein said fuel comprises 5 mol. % or more of hydrocarbons, 0.5-20 mass % of oxygenates therein in terms of an oxygen content based on the whole fuel and 5 mol. % or less of hydrocarbons having carbon numbers of 2 or less, 90 mol. % or more of hydrocarbons having carbon numfbers of 3 and 4 in total, 5 mol. % or less of hydrocarbons having carbon numbers of 5 or more and is a gaseous phase under normal temperature and pressure.  
     
     
         2 . A fuel according to  claim 1 , wherein a sulfur content is 50 ppm by mass or less.  
     
     
         3 . A fuel according to claims  1  or  2 , wherein said hydrocarbons comprises 60 mol. % or more of saturates, 40 mol. % or less of olefins, 0.5 mol. % or less of butadione, 0.1 mol. % or more of isoparaffin in saturates having carbon atoms of 4 or more, and is a gaseous phase under normal temperature and pressure.  
     
     
         4 . A fuel according to any one of  claims 1  to  3 , wherein vapor pressure at 40° C. is 1.55 MPa or less.  
     
     
         5 . A fuel according to any one of  claims 1  to  4 , wherein density at 15° C. is 0.500 to 0.620 g/cm 3 .  
     
     
         6 . A fuel according to any one of  claims 1  to  5 , wherein corrosiveness to copper at 40° C. for 1 hour is 1 or less,  
     
     
         7 . A fuel according to any one of  claims 1  to  6 , wherein heat capacity of the fuel is 1.7 kJ/kg ° C. or less at 15° C. in gaseous phase.