NOVELTY - A fuel cell system comprises an emulsion composition fed to a reformer at start-up. The emulsion composition comprises at least 40 wt.% hydrocarbon, 30-60 wt.% water and 0.01-5 wt.% surfactant mixture comprising (i) alkoxylated alkyl alcohol, alkoxylated alkyl monoester and/or alkoxylated alkyl diester and (ii) alkyl polyglycerol monoester and/or alkyl polyglycerol diester.    USE - Used as a fuel cell system.    ADVANTAGE - Using an emulsion at start-up achieves a well-mixed water/fuel injection. This improves the efficiency of start-up of the reformer. The fuel-water mixture can be sprayed into the reformer as opposed to introducing vapors of the individual components into the reformer.    DETAILED DESCRIPTION - A fuel cell system comprises a reformer to produce hydrogen-containing gas for use in a fuel cell stack. At start-up, an emulsion composition is fed to the reformer. The emulsion composition comprises at least 40 wt.% hydrocarbon, 30-60 wt.% water and 0.01-5 wt.% surfactant mixture comprising at least one surfactant from each of two types of surfactants. One type of surfactant comprises alkoxylated alkyl alcohol, alkoxylated alkyl monoester or alkoxylated alkyl diester. The other type of surfactant comprises alkyl polyglycerol monoester or alkyl polyglycerol diester. The alkoxylated alkyl alcohol is of formula R-(CH2)n-O-(M-O)m-H. The alkoxylated alkyl monoester is of formula R-(CH2)n-CO-O-(M-O)m-H. The alkoxylated alkyl diester of formula R-(CH2)n-CO-O-(M-O)m-CO-(CH2)n-R.    R = methyl;    n = 5-17;    m = 2-50; and    M = CH2-CH2, CH2-CH2-CH2, CH2-CH-CH3, CH2-CH2-CH2-CH2, and/or CH2-CH-(CH3)-CH2.    The alkyl polyglycerol monoester is of formula R'-CO-O-CH2-CHOH-CHOH-(CHOH-CHOH-CHOH)p-CHOH-CHOH-CH2OH. The alkyl polyglycerol diester is of formula R'-CO-O-CH2-CHOH-CHOH-(CHOH-CHOH-CHOH)p-CHOH-CHOH-CH2-O-CO-R'.    R' = 2-26C alkyl; and    p = 0-15.    INDEPENDENT CLAIMS are also included for: the following:    (1) the preparation of a complex oil-in-water-in-oil emulsion comprising mixing at 0.15 x 10 power -5 - 0.15 x 10 power -3 kW/L of fluid, at least 40 wt.% hydrocarbon, 30-60 wt.% water and 0.01-5 wt.% surfactant mixture; and    (2) a complex oil-in-water-in-oil emulsion comprising at least 40 wt.% hydrocarbon, 30-60 wt.% water and 0.01-5 wt.% surfactant mixture.