An apparatus and method to desulfurize a biogas containing sulfur. Since biogas is produced by an anaerobic digester from human, animal, kitchen and agriculture's wastes, it is a short term recycled product from the photosynthesis of CO2, and has a net zero carbon emission. The sulfur compounds in the biogas can be removed by the following steps: (1) converting all sulfur compounds into H2S by the hydrogen produced from the biogas over Pt group metal catalysts; (2) adsorbing the H2S at high temperature by the regenerable Pt group metal catalyst and adsorbents. The desulfurized biogas is further converted by an ATR/CPO reformer or a steam generating reformer to produce various reformates.