Isao Takehara

MAT, a novel, open cycle gas turbine for power augmentation

Abstract A Moisture Air Turbine (MAT) cycle is proposed for improving the characteristics of land-based gas turbines by injecting atomized water through an inlet into a compressor. Compressor work of isentropic compression for moist air mixtures with phase change is theoretically considered, which has revealed that water evaporation may reduce compressor work. An experiment using a 15 MW class axial flow load compressor has also verified the theory. Realistic cycle model calculations predict that a 10% power increment by a ratio of 1% water to compressor intake air is expected and also that the amount of water consumption is much less than that of conventional inlet air cooling systems, used for heat rejection at the cooling tower. In addition, thermal efficiency is anticipated to be improved mainly due to the reduction of compressor work. Contrary to the conventional evaporative cooler, a MAT cycle could provide power output at a desired value within its capability regardless of ambient humidity condition.

A New Gas Turbine Cycle for Economical Power Boosting

A Moisture Air Turbine (MAT) cycle is proposed for improv- ing the characteristics of land based gas turbine by injecting atomized water at inlet to compressor. The power boosting mechanism of MAT is understood as composits of those of following existing systems: inlet air cool- ing system, inter-cooling and steam injection. Experiments using a 15MW class axial flow load compressor have been carried out to reveal that water evaporation in compressor could reduce compressor work in an efficient manner. Moreover, this technol- ogy has been demonstrated by means of 130MW class simple cycle gas turbine power plant to show that a small amount of water consumption is sufficient to increase power output. Very efficient evaporation could be achieved provided the size of water droplet is controlled properly. The amount of water con- sumption is much less than that of conventional inlet air cooling system with cooling tower for heat rejection. Incorporating water droplet evaporation profile into considera- tion, realistic cycle calculation model has been developed to predict power output with water injection. It has been shown that this technology is economically achiev- able. It should be stressed that contrary to well known evapora- tive cooler, MAT cycle could provide power output at a desired value within its capability regardless of ambient humidity condi- tion.