摘要:
To provide a method for controlling a NOx reduction system which can remove NO x with a satisfactorily high efficiency even under low-temperature operating conditions as in diesel cars. The NO x reduction system comprises NO x treatment means disposed in an exhaust passage in an internal combustion engine, and air-fuel ratio control means for bringing the air-fuel ratio of an exhaust gas to a lean or rich state. The NO x treatment means comprises at least a first catalyst layer containing a solid acid catalyst capable of adsorbing ammonia and a second catalyst layer containing a noble metal and a cerium oxide material. The second catalyst layer and the first catalyst layer are stacked in that order on a carrier, and the first catalyst layer constitutes the uppermost layer. The air-fuel ratio control means controls so that the lean state and the rich state are repeated at predetermined intervals. According to the above constitution, NO x is passed through the first catalyst layer in the lean state and is temporarily stored in the second catalyst layer. Thereafter, in the rich state, NO x is converted to NH 3 and is restored in the first catalyst layer. When the state is again returned to the lean state, NH 3 is converted to nitrogen which is finally released from the first catalyst layer.
摘要:
Processes for reforming, and in particular aromatising, hydrocarbons from a petroleum source may be carried out by contacting the hydrocarbons with a catalyst of a zeolite KL impregnated with a metal promotor such as platinum, in which the zeolite crystals are of hockeypuck shape. The processes have a good yield and selectivity for the desired reformed products and the catalyst is stable, is associated with a low rate of coke formation, and has a long catalytically active life before regeneration is required.
摘要:
A process is provided for separating benzene from non-aromatics in a highly aromatic stream containing olefins in a concentration range of from about 0.05 to about 5.0, which process comprises predistilling said highly aromatic stream to produce a distilled fraction having a concentration of C8 and heavier compounds of less than about 0.1 wt. percent; and extracting said distilled fraction with a solvent comprising substituted morpholines in an extractive distillation zone to produce a highly-pure benzene stream.
摘要:
The invention provides for a process for dewaxing a waxy hydrocarbon feedstock to form a lubricant oil. The invention is also directed to a catalyst system comprising a hydrotreating catalyst upstream of a dewaxing catalyst, used in the dewaxing of a waxy hydrocarbon feedstock to form a lubricant oil. In particular, the invention is directed to a process and catalyst system designed to maintain yield of lubricant oil product. Specifically, the yield of lubricant oil does not decrease more than 2%, at a target pour point, over a dewaxing temperature range. The hydrotreating catalyst helps prevent aging of the dewaxing catalyst and maintains lubricant oil product yield at a target pour point over a wide temperature range. The hydrotreating catalyst comprises platinum, palladium, or combinations thereof on a low acidity inorganic oxide support where acidity is measured by a decalin conversion of less than 10% at 700F.
摘要:
There is provided a method of removing reactive metal from a metal-coated hydrocarbon conversion reactor system, comprising: contacting at least a portion of a metal-coated hydrocarbon conversion reactor system comprising a reactive metal with a getter to produce a movable metal; removing said movable metal from the metal-coated hydrocarbon conversion reactor system; and fixating said movable metal.
摘要:
A method of removing reactive metal from a metal-coated reactor system, comprising contacting at least a portion of a metal-coated reactor system containing reactive metal with a getter to produce movable metal, and fixating the movable metal, the getter, or both. The contacting is preferably done prior to catalyst loading. A preferred coating metal comprises tin and a preferred getter comprises HCl. The invention is also a method for reducing catalyst contamination from a metal which was used to coat a reactor system. The method comprises contacting a metal-coated reactor system, with a gaseous halogen-containing compound to produce movable metal; thereafter or simultaneously, at least a portion of the movable metal is removed from the reactor system. Then a halided catalyst is loaded into the reactor system.