Numerical study on sulfur-bearing natural gas oxy-fuel combustion power plant

Abstract

• A sulfur-bearing natural gas power plant adopting transcritical CO 2 cycle is built. • Oxy-fuel combustion technology is employed to reach near zero CO 2 emission. • The effect of sulfur content of fuel and combustion diluent are studied. • The efficiency of the proposed systems with recycled flue gas can reach 67.59%. Waste heat recovery technology can significantly improve the efficiency of oxy-fuel combustion system. The restriction of the acid dew point of the flue gas is essential to be considered due to the low-temperature corrosion during the waste heat recovery process. In this paper, a sulfur-bearing natural gas oxy-fuel combustion power plant is established to explore the effect of sulfur content on the system performance. Sulfur content (taking H 2 S as an example) in natural gas is set to 1 ppmv-1 vol%. Three different diluents of recycled flue gas, H 2 O and CO 2 are adopted to moderate the combustion temperature. Transcritical CO 2 cycle is introduced to efficiently utilize flue gas waste heat. As H 2 S content increases from 1 ppmv to 1 vol%, the power generation efficiency of recycled flue gas system, H 2 O system and CO 2 system decreases by 0.61%, 1.15% and 1.65%, respectively. When H 2 S is 1 ppmv, the energy efficiency can reach 67.59% in recycled flue gas system, 18.74% and 12.09% respectively higher than H 2 O and CO 2 system. The recycled flue gas system is preferred to be applied in the oxy-fuel power generation system driven by sulfur-bearing natural gas, which can improve energy efficiency and reduce environmental impact.