| abstract |
Provided are a combustion exhaust gas purifying catalyst and a method for purifying combustion exhaust gas which, when used, e.g., in the removal of nitrogen oxides in relatively low-temperature exhaust gases discharged from an internal combustion engine such as a marine diesel engine, improves the selectivity of an alcohol reducing agent in a denitration reaction in comparison with previous methods, thereby improving the denitration performance of the reducing agent even in amounts equivalent to those in previous methods so that exhaust gas treatment takes place with higher efficiency. This denitration catalyst is employed in a method for purifying combustion exhaust gas involving being brought into contact with a combustion exhaust gas to which alcohol has been added as a reducing agent so as to remove nitrogen oxides from the exhaust gas, and is characterized in that a catalyst metal is supported on a zeolite support, and in powder X-ray diffraction (XRD) measurements of the denitration catalyst, the ratio (relative peak intensity ratio) r = I/J, where I is the diffraction peak height at a diffraction angle (2θ) of 7.8-10.0°, and J is the diffraction peak height at a diffraction angle (2θ) of 28.0-31.0°, is in the range of 3.0-5.0. |