Abstract: The invention provides a gas turbine intake air filter unit, wherein flow resistance of intake air passing through a tertiary filter layer does not become unreasonably great despite the filter layers are increased from two stages to three stages, and a balance of collecting efficiency of the filter layers and the intake air flow resistance is optimized. A weather louver 10, a primary filter layer 11, a secondary filter layer 12, and a tertiary filter layer 13 are sequentially disposed from an upstream side in the filter unit 1 installed at an upstream side end portion of an intake duct 2 communicating with a gas turbine 3, at least a recess 13e is formed toward a downstream side of the intake air flow A′ on an end face filter layer portion 13a that is a constituent of the tertiary filter layer 13 and is disposed orthogonally to the intake air flow A′ inside the intake duct 2.

Abstract: The invention provides a gas turbine intake air filter selecting system that works in accordance with density or nature of dust around a location of an individual gas turbine and with capacity and characteristics of the gas turbine.

Abstract: The invention provides a gas turbine intake air filter unit, wherein flow resistance of intake air passing through a tertiary filter layer does not become unreasonably great despite the filter layers are increased from two stages to three stages, and a balance of collecting efficiency of the filter layers and the intake air flow resistance is optimized.

Abstract: A method for treating an exhaust gas which includes leading a coal-fired exhaust gas to a dry denitrating device, removing oxides of nitrogen from the exhaust gas in the device, leading the exhaust gas to a dry electric dust collector and a wet waste smoke desulfurizing device disposed at downstream positions, and removing dust from the exhaust gas in these devices. A sodium compound containing solution is sprayed into the exhaust gas flowing between the dry denitrating device and the dry electric dust collector thereby increasing the efficiency of the dust collector, and the resulting dry solids are then collected together with the dust by the dry electric dust collector.