Honeycomb structure and catalyst for cleaning exhaust gas using same, and method for producing catalyst for cleaning exhaust gas

#The present invention relates to a honeycomb structure, which are used, for example, in a cleaning method for removing a nitrogen oxide (NOx) from a combustion exhaust gas, a catalyst for cleaning an exhaust gas using the same, and a method for producing a catalyst for cleaning an exhaust gas.

#For example, an exhaust gas discharged from a marine vessel engine has a high sulfur oxide (SOx) concentration and a high nitrogen oxide (NOx) concentration in the exhaust gas due to the use of a C fuel as a fuel, and ammonia (NH3) or the like used as a reducing agent for a denitration reaction is reacted with a sulfur oxide (SOx) to form ammonium sulfate. The exhaust gas from the marine vessel engine has a temperature of 300° C. or less, and generally approximately 250° C., and under the condition, ammonium sulfate is generated in the exhaust gas to fail to retain the stable catalyst capability.

#Patent Literature 1 below discloses an exhaust gas cleaning method using a catalyst having a denitration capability removing a nitrogen oxide (NOx) even in an exhaust gas containing a sulfur oxide, and describes an exhaust gas cleaning method for reducing and removing a nitrogen oxide NOx in an exhaust gas in such a manner that β-zeolite having supported thereon iron, cobalt, silver, molybdenum, or tungsten is used as the denitration catalyst, and an oxygen excessive exhaust gas is made in contact therewith in the presence of ethanol and/or isopropyl alcohol as a reducing agent.

#FIG. 1 is a flow chart showing one example of a denitration rate measuring instrument used in the catalyst capability test in the example of the present invention.

#Embodiments of the present invention will be described in detail below.

#The honeycomb structure according to the present invention consists of a flat inorganic fiber sheet comprising an inorganic fiber sheet having supported thereon an inorganic binder and zeolite, and a corrugated inorganic fiber sheet comprising an inorganic fiber sheet having supported thereon the same inorganic binder and zeolite, which are alternately combined with each other, wherein it is characterized in that the zeolite has a particle diameter (i.e., a median particle diameter, D50) of from 0.5 to 10.0 μm, and preferably from 3.0 to 7.0 μm.

#The particle diameter of the zeolite herein means a particle diameter corresponding to 50% in the volume-based cumulative particle size distribution (i.e., a median particle diameter, D50) measured by a laser diffraction method.