Demonstration of direct spray combustion of liquid ammonia by 2MW-class gas turbine

Abstract

To reduce greenhouse gas emission from gas turbine, the liquid ammonia direct spray combustor has been developed. Demonstration test used 2MW-class gas turbine was conducted, and performance of the combustor was evaluated. As a result, it confirmed that the supply system of liquid ammonia is simpler than that of gaseous ammonia, which is effective in saving footprint and shortening the start-up time of gas turbine. It found that liquid ammonia burns stably and unburnt NH₃ emission was suppressed up to a co-firing ratio of 70%. On the other hand, NOx concentration is higher than that of gaseous ammonia combustion, but it can be reduced below very low level by a standard NOx removal catalyst. N₂O concentration slightly increase with increasing liquid ammonia supply rate. It indicates that flame temperature decreases due to latent heat of vaporization of liquid ammonia. However, the effect of N₂O emission on greenhouse reduction ratio was minor, greenhouse gas reduced up to 68% comparing with natural gas alone firing. These results show liquid ammonia can be used for gas turbine fuel.