摘要:
A process for a shape selective hydrocarbon conversion such as toluene disproportionation, involves contacting a reaction stream under conversion conditions with a catalytic molecular sieve which has been preselectivated by agglomerating with an organosilicon compound.
摘要:
A shape-selective catalyst comprises a synthetic porous crystalline material having the structure of ZSM-5 and a composition involving the molar relationship: X2O3:(n)YO2, wherein X is a trivalent element, such as aluminum, boron, iron and/or gallium, preferably aluminum; Y is a tetravalent element such as silicon and/or germanium, preferably silicon; and n is greater than about 12, and wherein the crystals have a major dimension of at least about 0.5 micron and a surface YO2/X2O3 ratio which is no more than 20 % less than the bulk YO2/X2O3 ratio of the crystal. The crystals have a diffusion-modifying surface coating of a refractory material such as silica or coke. The catalyst is useful in a wide variety of selective hydrocarbon conversion processes, particularly the selective disproportionation of toluene to para-xylene.
摘要:
Oxides of nitrogen (NOx) emissions from an FCC regenerator (30) are reduced by operating the regenerator (30) in partial CO burn mode to produce flue gas with more CO than O2 and with NOx precursors. This flue gas is then enriched with controlled amounts of oxygen and charged over catalyst, preferably Group VIII noble metal on a support, to convert most NOx precursors to nitrogen. Flue gas may then be charged to a CO boiler (89). Eliminating more than 90 % of NOx emissions is possible by operating the FCC regenerator (30) in partial CO burn mode, then adding air and catalytically converting NOx precursors at substoichiometric conditions. Conversion of NOx if formed in the regenerator (30) may be achieved as well.
摘要:
In a synthetic porous crystalline material having the structure of ZSM-5 and a composition involving the molar relationship: X2O3:(n)YO2, wherein X is a trivalent element; Y is a tetravalent element; and n is greater than about 12, the crystals have a major dimension of at least about 0.5 micron and surface framework YO2/X2O3 ratio which is no more than 20 % less than the bulk framework YO2/X2O3 ratio of the crystal. The material is synthesized using an amino-acid as a directing agent.
摘要:
MCM-56 and MCM-49 have been demonstrated to be effective catalysts for the reduction of nitrogen oxide (NOx) emissions in a net oxidizing environment such as Selective Catalytic Reduction or lean burn engine exhaust applications. MCM-56 and MCM-49 can be utilized as a component of a spherical or cylindrical catalyst particle or as a wash coat on a ceramic or metallic monolith. Optionally, a transition metal such as copper, can be added to the catalyst for improved activity.
摘要:
A catalytic process for the treatment of exhaust containing NOx along with other undesirable compounds is described. One embodiment of the process comprises a catalytic stage to selectively catalytically reduce NOx over an intermediate pore size zeolite catalyst that has been treated or modified to contain iron and then has been hydrothermally treated at least one time.
摘要:
A feedstock containing one or more C9+ aromatic compounds, and optionally toluene, is converted over a catalyst comprising a zeolite possessing a Constraint Index of 1 to 3 to provide a product which contains substantial amounts of benzene and xylene(s).
摘要:
In a process for modifying the shape selectivity of an aluminosilicate zeolite catalyst having a silica to alumina molar ratio less than 500, the catalyst is exposed to at least two ex situ selectivation sequences, wherein each ex situ selectivation sequence includes the steps of contacting the catalyst with a selectivating agent, normally an organosilicon compound, in a carrier and subsequently calcining the catalyst.
摘要:
Une charge contenant un composé C9+ aromatique ou davantage et éventuellement du toluène, est convertie par un catalyseur comprenant un zéolite possédant un indice de contrainte de 1 à 3 pour donner un produit contenant des quantités importantes de benzène et de xylène(s).