Catalytic reforming processes
Processes for catalytic reforming in which a cracking inhibitor, such as an olefin, or a light olefin, is used to inhibit thermal cracking of larger hydrocarbons in non-reactive zones. The cracking inhibitor may be added at various positions through the processes, such as in the recycle gas stream, before a heater, before a stream is passed into a reforming zone, after an effluent stream is recovered from a reforming zone. A molar ratio of cracking inhibitor to hydrocarbons in stream may be between 0.01 and 0.2.
1. A process for reducing the thermal cracking in a catalytic reforming unit, the process comprising:
heating a feed stream comprising hydrocarbons in a first heating zone and passing the feed stream from the first heating zone to a first reforming zone;
reforming the hydrocarbons in the feed stream in the first reforming zone, the first reforming zone having catalyst and being configured to provide a reformate effluent stream;
recovering the reformate effluent stream from the first reforming zone;
mixing the reformate effluent stream with a light olefin stream as a cracking inhibitor to reduce thermal cracking of hydrocarbons before the reformate effluent stream is passed to a second reforming zone, wherein a molar ratio of light olefins to hydrocarbons in the reformate effluent stream is between 0.01 and 0.2;
passing the reformate effluent stream to the second heating zone and heating the reformate effluent stream in the second heating zone;
passing the reformate effluent stream from the second heating zone to a second reforming zone; and,
reforming the hydrocarbons in the reformate effluent stream in the second reforming zone, the second reforming zone having catalyst and being configured to provide a second reformate effluent stream.
2. The process of claim 1 further comprising:
mixing the feed stream with a light olefins stream before the feed stream is passed to the first reforming zone.
3. The process of claim 2 , wherein a molar ratio of light olefins to hydrocarbons in the feed stream is between 0.01 and 0.2.
4. The process of claim 3 further comprising:
mixing the second reformate effluent stream with a light olefins stream.