A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, a dust collector 50 that is disposed in the exhaust line L1 and that collects dust in the exhaust gas, and a denitration device 90 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 90 is disposed downstream from the dust collector 50 in the exhaust line L1. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

A catalyst substrate may include a ceramic base body including first and second ends, the second end being opposite to the first end, and the ceramic base body being provided with a plurality of cells each extending between the first and second ends; and a plurality of metal particles or metal fragments introduced into one or more internal spaces of one or more selected cells in the plurality of cells. Each of the plurality of metal particles or metal fragments has a size equal to or less than an opening width of the cell. The plurality of metal particles or metal fragments is configured to generate heat in accordance with varying magnetic field.

A honeycomb structure including: a pillar-shaped honeycomb structure portion having an outer peripheral wall and partition walls disposed on an inner side of the outer peripheral wall and defining a plurality of cells extending from one end face to another end face to form flow paths; and at least an electrode portion disposed on an outer surface of the outer peripheral wall of the pillar-shaped honeycomb structure portion, wherein the pillar-shaped honeycomb structure portion is formed of ceramics containing either or both of Si and SiC, the electrode portion contains either or both of a metal and a metal compound in addition to an oxide, and a volume ratio of the oxide on an inner peripheral side of the electrode portion is higher than a volume ratio of the oxide on an outer peripheral side of the electrode portion.

There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst molded in a block shape contains 43 wt % or more of vanadium pentoxide. The denitration catalyst has a BET specific surface area of 30 m.sup.2/g or more and is used for denitration at 200 C. or lower.

A honeycomb body for exhaust-gas aftertreatment and a method for producing the honeycomb body for exhaust-gas aftertreatment, the honeycomb body having a housing and a honeycomb structure with a multiplicity of channels. The honeycomb structure is formed with a partially structured layer and a smooth layer the smooth layer provides that, in at least one axial portion of the honeycomb structure, a first cell density in an inner radial zone is increased in relation to a second cell density in an outer radial zone.

An assembly for treating gaseous emissions has a substrate along which extend cells for the passage of emissions gas. Lengths of conducting wire are located in a set of the cells and an induction heating coil is used to generate a varying electromagnetic field, so as to inductively heat the lengths of conducting wire. The substrate body has a front for entry of flowing emissions gas to be treated into the substrate body and a back for exit of treated gaseous emissions gas. The lengths of conducting wire have projections extending from the front and/or back of the substrate body so that when inductively heated, the wire parts in the substrate body heat the surrounding substrate and the wire projections heat the flowing emissions gas directly.

An exhaust gas treatment device (1), for an exhaust system of an internal combustion engine, is equipped with a housing (2). At least one mounting pipe (3), which contains a mounting space (4), is arranged within the housing. At least one cartridge (5) is arranged replaceably in the mounting space (4) and has a cartridge pipe (6) as well as at least one exhaust gas treatment element (7) arranged in the cartridge pipe (6). The cartridge pipe (6) is supported axially under axial prestress at an annular step (9) at least on an axial front side (31) via at least one spring element (27).

A catalyst carrier may have a cross-sectional shape that may include a plurality of surface channels having a first channel width and a second channel width, where the first channel width may be closer to a periphery of the cross-sectional shape than the second channel width and the first channel width may be less than the second channel width. The cross-sectional shape may further include a plurality of surface features where at least one surface feature is located between at least one pair of surface channels. The cross-sectional shape may further include a ratio L.sub.OC/L.sub.SCP of at least about 1.7, where L.sub.OC is a length of a total contour of the cross-sectional shape and L.sub.SCP is a length of an outer simple convex perimeter of the cross-sectional shape.

There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst is obtained by coating a substrate with a catalyst component. The catalyst component contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more. The denitration catalyst is used for denitration at 200 C. or lower.

A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, a dust collector 50 that is disposed in the exhaust line L1 and that collects dust in the exhaust gas, and a denitration device 90 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 90 is disposed downstream from the dust collector 50 in the exhaust line L1. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.