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.

The present invention concerns a material with a non-stoichiometric spinel-type crystalline structure based on cobalt oxide doped with alkaline elements, its production process for obtaining it by precipitation with controlled washing, and its particular use as a highly active catalyst in the N.sub.2O decomposition reaction. Therefore, we understand that the present invention is in the area of green industry aimed at reducing N.sub.2O emissions into the atmosphere.

The present invention relates to a calcined medium, in particular a catalyst or a catalyst medium or an adsorbent/absorbent mass, in particular in the form of extrudates, pellets, granules or beads, the medium comprising a porous matrix comprising carbonates, clays, zeolites, oxides, or metal and/or silicon hydroxides, and the matrix incorporating hollow mineral microspheres having a different composition in a content of between 0.3 and 50% by weight, in particular between 0.5 and 15% by weight, of the matrix.

Provided is a method for using selective non-catalytic reduction to reduce nitrogen dioxide in exhaust gas generated during an olefin production process. Nitrogen dioxide generated in a catalyst regeneration step of a continuous PDH process can be efficiently removed by the method of the present disclosure. Ultimately, the generation of visible fumes can be prevented through the removal of nitrogen dioxide.

An apparatus for collecting a gaseous pollutant from air may comprise multiple vertical panel-beds each containing a solid sorbent; a fan to pass the air through the multiple vertical panel-beds and over the solid sorbent; an outlet gate configured to release the solid sorbent from the multiple vertical panel-beds after the fan passes the air over the solid sorbent; a regeneration vessel configured to regenerate the released solid sorbent by recovering the gaseous pollutant from the released solid sorbent; and a conveyor configured to return the regenerated solid sorbent to the multiple vertical panel-beds.

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.

A method and apparatus for purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system can include passing air through a first adsorber of the PPU to purify the air for operation of the ASU system while it is at or below a first pre-selected operational capacity. In response to the operational capacity of the ASU system needing to be increased to a level above the first pre-selected operational capacity threshold, a second adsorber can be brought on-line in parallel with the first adsorber or in series with the first adsorber to provide improved purification capacity to account for the increased demand for purification capacity resulting from the increased operational capacity of the ASU system. This second adsorber can be different from the first adsorber (e.g. different in size, adsorption capacity for impurities within air, and/or configuration, etc.).

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.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.

The present invention relates to a process for preparing a catalyst for the selective catalytic reduction of nitrogen oxide comprising, among other steps, preparing a second aqueous mixture comprising water and an iron salt; and disposing the second mixture on the substrate obtained according to (ii), comprising a coating comprising a zeolitic material comprising copper, over y % of the substrate axial length from the inlet end to the outlet end of the substrate, wherein y is in the range of from 10 to x, obtaining a substrate comprising, in a first zone, the coating comprising a zeolitic material comprising copper and over y % of the substrate axial length an iron salt; and, if x > y, in a second zone extending from y % to x % of the substrate axial length from the inlet end to the outlet end, the coating comprising a zeolitic material comprising copper.