摘要:
A flue gas that contains small amounts of both HCN and NO.sub.x, produced, for example, by catalyst regeneration in the fluid catalytic cracking of a petroleum gas oil, is readily denitrified by the catalyzed reaction that proceeds approximately according to:HCN+NO.fwdarw.N.sub.2 (gas)+CO+CO.sub.2 +H.sub.2 OIf the molar ratio of HCN to NO in the flue gas is about 1.0, e.g. in the range of about 0.8 to 1.2, effective denitrification is achieved without first changing the composition of the flue gas by contacting it with catalyst under conversion conditions including elevated temperature. If the molar ratio of HCN to NO exceeds 1.2, the ratio may be adjusted to about 1.0 to 1.1 by thermal or catalytic oxidation in the presence of oxygen gas, followed by catalytic denitrification. If the molar ratio is less than about 0.8, the effective molar ratio is adjusted to about 1.0 to 1.1 by adding NH.sub.3 gas, followed by denitirification. In all three instances an excessive content of carbon monoxide in the flue gas may be corrected by passing the denitrified flue gas to a CO-boiler.Catalysts for the denitrification reaction are described and exemplified by crystalline zeolites of the ZSM-5 type, and by vanadium oxide supported on titania.
摘要翻译:含有少量HCN和NOx的烟道气,例如通过在石油瓦斯油的流化催化裂化中的催化剂再生产生的烟气,可以通过大致按以下方式进行的催化反应脱氮:HCN + NO-> N2(气体)+ CO + CO2 + H2O如果烟气中HCN与NO的摩尔比为约1.0, 在约0.8至1.2的范围内,无需首先在包括升高的温度的转化条件下将催化剂与催化剂接触,而不改变烟道气的组成,实现有效的脱氮。 如果HCN与NO的摩尔比超过1.2,则在氧气存在下通过热或催化氧化将该比例调节至约1.0至1.1,然后进行催化反硝化。 如果摩尔比小于约0.8,则通过加入NH 3气体将有效摩尔比调节至约1.0-1.1,然后进行脱硝。 在所有三种情况下,可以通过将反硝化烟道气通过CO锅炉来校正烟道气中过量的一氧化碳。 用于脱氮反应的催化剂通过ZSM-5型的结晶沸石和负载在二氧化钛上的氧化钒来描述和例示。
摘要:
Conversion of benzene to heavier aromatics by contact with alkyl polynucleararomatics, preferably FCC heavy cycle oil, in the presence of an alkylation/transalkylation catalyst is disclosed. Efficient conversion of relatively dilute benzene in reformate is possible. Use of alkyl polynucleararomatics as a source of alkyl groups, with reduced use of monocyclic alkyl aromatics, permits robust reaction conditions to be used without a net formation of benzene by dealkylation. The process preferably uses a solid zeolite based acidic catalyst disposed in a fixed, moving or fluid bed reactor. Preferred catalysts comprise MCM-22 or ZSM-5.
摘要:
The operating performance of a tubular reactor system designed for the exothermic conversion of methanol to light olefins is improved by cofeeding small quantities of light olefins with the methanol feed, whereby a more controllable operation is achieved. Catalyst activity and cycle length also improves significantly. The light olefins can be produced in situ during conversion.
摘要:
A process for reducing the benzene content of a reformate stream in a conventional catalytic cracking reactor wherein a heavy hydrocarbon feed is cracked to lighter products by contact with a supply of hot regenerated cracking catalyst is disclosed. The reformate can be mixed with the heavy feed to the cracking reactor, but preferably reformate contacts hot regenerated cracking catalyst before the heavy feed is added. Benzene content is reduced by alkylation with reactive fragments created in the cracking reactor, or by transalkylation with alkyl aromatics. Benzene removal can be enhanced by adding a light reactive gas such as ethylene to the cracking reactor, by adding heavier aromatics, such as a light cycle oil, or both. The reaction is preferably conducted in an FCC riser reactor, but may be conducted in a moving bed cracking reactor.
摘要:
A catalytic cracking process especially useful for the catalytic cracking of high metals content feeds including resids in which the feed is cracked in the presence of a catalyst additive comprising an alkaline earth metal oxide and an alkaline earth metal spinel, preferably a magnesium aluminate spinel which acts as a trap for vanadium as well as an agent for reducing the content of sulfur oxides in the regenerator flue gas. The additive is used in the form of a separate additive from the cracking catalyst particles in order to keep the vanadium away from the cracking catalyst and so preserve the activity of the catalyst; in addition, use of separate additive particles permits the makeup rate for the additive to be varied relative to that of the cracking catalyst in order to deal with variations in the metals and sulfur content of the cracking feed. The additive may be separated from the cracking catalyst by physical classification so that it can be separately withdrawn from the unit for better control of the catalyst/additive ratio. The additive may be injected into the unit separate from the cracking catalyst so that it contacts the feed first to effect a preliminary demetallation.
摘要:
An improved process and apparatus are disclosed for fluidized bed catalyst regeneration in a cross-flow type regenerator. A baffled coked catalyst inlet located within the dense bed of catalyst disperses and distributes coked catalyst flow in a direction generally normal to the direction of flow in the catalyst inlet. The baffle significantly reduces the stagnant regions in the bed.
摘要:
Catalyst stripping in the fluid catalytic cracking process is improved by cooling the spent catalyst to quench catalytic condensation reactions, then stripping the cooled catalyst in a primary stripper, followed by heating and a stage of hot stripping. Quenched stripping reduces coke make by reducing conversion of light olefins, made during the FCC process, into coke.
摘要:
Operational flexibility of a fluid catalytic cracking process is improved by indirectly cooling catalyst in an endothermic catalyst cooler. Catalyst withdrawn from the FCC unit is cooled by driving an endothermic chemical reaction, which may be either thermal or catalytic. Dehydrogenation of, e.g., light aliphatics, produced by the cracking reactor in the endothermic cooler allows the FCC unit to adapt to heavier feeds. A preferred endothermic cooler, comprising a base heat exchanger section, transport riser, and solids collection and recycle vessel is disclosed.
摘要:
An process and apparatus are disclosed for fluidized bed catalyst regeneration in a cross-flow type regenerator. A baffled coked catalyst inlet located within the dense bed of catalyst disperses and distributes coked catalyst flow in a direction generally normal to the direction of flow in the catalyst inlet. The baffle significantly reduces the stagnant regions in the bed.
摘要:
An improved process and apparatus are disclosed for fluidized catalytic cracking of hydrocarbons using a cross-flow or swirl type catalyst regenerator. Instead of a single catalyst withdrawal outlet for regenerated catalyst, multiple catalyst withdrawal points are provided. Use of multiple catalyst outlets, or a continuous radial catalyst outlet, greatly reduces stagnant regions in the bed.