(513fv) Development of Direct Spray Combustion Technology of Liquid Ammonia for Gas Turbine Combustor

Ammonia has several advantages; established manufacturing process, easy liquefaction for transportation and storage, to use as the renewable energy career. However, to use the ammonia as a fuel for electric power generation, it is necessary to solve the problem of low flammability and increase in NOx emission. For gas turbine combustor, the effect of the two-stage combustion method has been demonstrated to achieve stable low NOx combustion. In these, combustion of gasified ammonia is intensively investigated. On the other hand, combustion of liquid ammonia by direct spray method is focused in this study. Liquid ammonia direct spray method has several advantages against gasified method. It does not require a vaporizer and accumulator for stable gasified ammonia supply. High ammonia mixing ratio can be achieved with a low cost pressurization system. Since there is no heat demand for operation, startup is possible in a short time. On the other hand, the effect of latent heat of evaporation of liquid ammonia on combustion stability and gas turbine efficiency is an issue to be clarified. In this study, gas turbine combustor co-firing liquid ammonia and natural gas was developed and its performance was confirmed by a rig test under atmospheric pressure conditions. Experimental results show that stable combustion is achieved up to a liquid ammonia mixing ratio of 70%. It was also confirmed that unburned ammonia and NOx emissions were within the allowable range of the de-NOx equipment. Therefore, results obtained in this study show that liquid ammonia direct spray method is applicable to gas turbine.

Acknowledgement; this work was supported by the New Energy and Industrial Technology Development Organization (NEDO).