摘要:
A process for preparing a molybdenum sulfide-based catalyst comprises drying a precipitated molybdenum sulfide-based catalyst precursor, for example, a wet filter cake, such that a particulate catalyst precursor, containing from 12 to 15 percent by weight water, is formed. The particulate catalyst precursor is desirably in the form of free-flowing particles. The particulate catalyst precursor is then auto-reduced. A rotary furnace that subjects the catalyst precursor to at least two zones having distinct temperatures may be conveniently used for drying, auto-reduction, or both. The staged drying and auto-reduction steps reduce the tendency of the precursor to self-heat, which is undesirable because it reduces both the activity and selectivity of the final catalyst.
摘要:
Increase propane dehydrogenation activity of a partially deactivated dehydrogenation catalyst by heating the partially deactivated catalyst to a temperature of at least 660° C., conditioning the heated catalyst in an oxygen-containing atmosphere and, optionally, stripping molecular oxygen from the conditioned catalyst.
摘要:
A process to prepare an olefin from its corresponding alcohol is improved by reacting, under reaction conditions including a first temperature, an aliphatic alcohol and, optionally, diluent water, to form a reaction product including at least a dialkyl ether. The product is then reacted again, under higher temperature to complete the dehydration of the dialkyl ether to the desired olefin. This process is particularly suitable to prepare ethene from ethyl alcohol. The stepped temperature scheme serves to reduce the formation of byproduct aldehydes, which in turn reduces coke formation, fouling, and the need to handle large amounts of water, thereby lowering energy and capital costs.
摘要:
A process for converting an oxygenate-containing feedstock to a product comprising olefins comprises including in the oxygenate-containing feedstock an amount of ammonia. The presence of the ammonia increases the product's ratio of ethylene to propylene.
摘要:
A process to prepare propylene showing desirably increased selectivity comprises contacting, at an elevated temperature, ethanol and a rhenium oxide-modified ZSM-5 zeolite catalyst, under conditions suitable to form propylene. The rhenium oxide-modified ZSM-5 zeolite catalyst may be prepared by impregnating, in an aqueous or organic medium, a ZSM-5 zeolite with a rhenium source, under conditions suitable to form a catalyst precursor, and calcining the catalyst precursor under conditions suitable to form a rhenium oxide-modified ZSM-5 zeolite catalyst.