Performance evaluation of honeycomb shaped sorbent for sulfur removal in advanced oxy-fuel IGCC power generation plant

Abstract

Oxy fuel IGCC is one of the promising option for reconciling environment and efficiency in power generation from coal that is expected to achieve thermal efficiency of 44% LHV and 99% of CO2 capturing ratio. Dry syngas cleaning technologies for halide and sulfur are essential for realizing the power plant. The dry desulfurization process will use honeycomb shaped sorbent in fixed bed reactors in actual plant. In this study, comparative evaluation was performed on two kinds of the sorbent with and without improvement on durability to the harmful carbon deposition. The effect of gas composition on the sorbent performance was evaluated at 450°C and 0.98MPaabs. When the severe condition for carbon deposition was applied to the sorbent without improvement, crucial carbon deposition occurred rapidly in the honeycomb sorbent. Thus, the deposited carbon caused collapse of sorbent structure and deterioration of sulfur removal performance. Once the deposited carbon accumulated to the sorbent, it could not be eliminated in the subsequent regeneration procedure. On the contrary, the improved sorbent was durable to carbon deposition even under the severe condition, so that sorbent structure and sulfur removal performance was retained. Thus, it is essential to avoid the rapid carbon deposition by enhancing sorbent durability to the carbon deposition and providing gas condition for retarding the harmful side reaction. The amount of deposited carbon did not exceed 1.0wt% even at the severe condition. The sorbent could exhibit sufficient sulfur removal performance for the first and second cycle desulfurization at the severe condition as well as at the gentle condition. These results confirmed that the sorbent has higher potential to be safely used in start-up condition as well as ordinary condition of expected dry sulfur removal process of oxy-fuel IGCC plant.