A system and method of pre-purification of a feed gas stream is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the hydrogen, carbon monoxide, water, and carbon dioxide impurities from a feed air stream and is particularly suitable for use in a high purity or ultra-high purity nitrogen plant. The pre-purification systems and methods preferably employ two or more separate layers of hopcalite catalyst with the successive layers of the hopcalite separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layers.

A recyclable ceramic catalyst filter, a filtering system including the same, and a method of managing the filtering system are provided. The ceramic catalyst filter has a monolithic structure including a first surface which blocks a first material; and a second surface which removes a second material that passed through the first surface, where the second surface is activated and operates as a catalyst layer which removes the second material in response to energy supplied to the second surface.

A catalytic article for treating exhaust gas comprising: a substrate comprising an inlet end and an outlet end with an axial length L; a first catalytic region comprising a first platinum group metal (PGM) component and a support; a second catalytic region comprising a second PGM component on a support with low ammonia storage and a first SCR catalyst; and wherein the first catalytic region is covered by at least another catalytic region.

A recyclable ceramic catalyst filter, a filtering system including the same, and a method of managing the filtering system are provided. The ceramic catalyst filter has a monolithic structure including a first surface which blocks a first material; and a second surface which removes a second material that passed through the first surface, where the second surface is activated and operates as a catalyst layer which removes the second material in response to energy supplied to the second surface.

The present disclosure is directed to a system for treating an exhaust gas stream from an engine, which includes a diesel oxidation catalyst (DOC) located downstream of the engine and adapted for oxidation of hydrocarbons and carbon monoxide, an injector adapted for the addition of a reductant to the exhaust gas stream located downstream of the DOC, a catalyzed soot filter (CSF) located downstream of the injector, and a selective catalytic reduction component adapted for the oxidation of nitrogen oxides located downstream of the CSF. The CSF is adapted for oxidizing hydrocarbons and includes a selective oxidation catalyst composition on a filter with high selectivity ratio for hydrocarbon oxidation:ammonia oxidation (e.g., at least 0.6).

The present disclosure provides catalyst compositions and catalytic articles capable of storing and/or reducing nitrogen oxide (NO.sub.x) emissions in engine exhaust, catalyst articles coated with such compositions, and processes for preparing such catalyst compositions and articles. The catalyst compositions include copper and palladium co-exchanged zeolites. Further provided is a process for preparing such co-exchanged zeolites, an exhaust gas treatment system including the catalytic articles disclosed herein, and methods for reducing NO in an exhaust gas stream using such catalytic articles and systems.

The present invention relates to a catalyst comprising a carrier substrate of the length L, which extends between a first end face ‘a’ and a second end face ‘b’, and differently composed material zones A and B arranged on the carrier substrate, wherein material zone A comprises platinum and no palladium or platinum and palladium with a weight ratio of Pt:Pd of ≥1 and, material zone B comprises a copper containing zeolite having a Cu/Al ratio of 0.355 or higher.

The invention relates to a process for preparing a catalyst based on an AFX zeolite exchanged with at least one transition metal, comprising at least the following steps:

i) mixing, in an aqueous medium, of at least one source of silicon (Si) in SiO.sub.2 oxide form, at least one source of aluminum (Al) in Al.sub.2O.sub.3 oxide form, 1,6-bis(methylpiperidinium)hexane dihydroxide, and at least one source of at least one alkali metal, until a homogeneous precursor gel is obtained;
ii) hydrothermal treatment at a temperature between 75° C. and 95° C., limits included;
iii) at least one ion exchange with a solution comprising at least one species capable of releasing a transition metal,
iv) heat treatment by drying followed by at least one calcination under a stream of air at a temperature between 400 and 700° C. The invention also relates to the catalyst obtained and to the use thereof for the selective reduction of NOx.

Proposed is a multi-layer filtration system including a metal catalyst filter unit, a carbon filter unit, and an inorganic compound filter unit. The metal catalyst filter unit includes at least one among metals including Ni, Co, Fe, Cu, Cr, Mg, Zn, Ba, Au, Ag, Pd, Pt, Ru, Mn, and Ti, oxides thereof, and mixtures thereof. The carbon filter unit includes at least one of activated carbon or activated carbon fiber. The inorganic compound filter unit includes an inorganic compound capable of adsorbing toxic gas. The multi-layer filtration system has good removal effect for toxic gas. A filter module including the multi-layer filtration system and a gas mask including the multi-layer filtration system are also proposed.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.