Honeycomb catalyst, denitration catalyst of denitration device, and exhaust gas denitration device

A flue gas NOx removal apparatus consisting of a plurality of NOx removal catalyst layers provided in the gas flow direction, each catalyst layer being composed of a plurality of honeycomb NOx removal catalysts juxtaposed in a direction crossing the gas flow direction,

• each honeycomb NOx removal catalyst having gas conduits including an aperture for feeding an exhaust gas from an inlet to an outlet of each conduit and performing NOx removal on the sidewalls of the conduit, the gas conduits constituting the plurality of the NOx removal catalyst layers each having approximately the same aperture size,
• characterized in that each of the NOx removal catalysts forming each NOx removal catalyst layer has an approximate length such that the flow of the exhaust gas which has been fed into the gas conduits is straightened in the vicinity of the outlet, that the length (Lb) is specified by a sustained turbulent flow distance (Lt) which is the distance from the inlet to a site where turbulent flow energy is lost in the course of transition from turbulent flow to laminar flow, and that two NOx removal catalyst layers adjacent to each other are disposed with a space therebetween, the space serving as a common gas conduit where exhaust gas flows discharged through the NOx removal catalysts are intermingled one another.