Q & A > Question Details
We designed and built an octanizing system for upgrading octane number of heavy naphtha fraction with 8 cubic meter per hour. This system have no a hydrotreating package, so naphtha feed goes directly through heater and then reactor.
Reactor dimension is 12 m length and 1.2 m diameter. But we use only 2.5 m length for containing catalyst (~1.8 tons). Internals have not inlet diffuser and distributor. Naphtha feed stream enter on the top and exit at bottom.
Heavy naphtha has distillation range 80 - 180 deg-C, RON 68.
Operating conditions are: inlet temperature 400 deg-C and 5 bar-g.
Catalyst is a kind of zeolite with 9 angstrom pore size. It was treated by impregnating in SnCl2 solution and calcinating at 500 deg-C in 8 hours.
We run a pilot as 6 lit per hour on 1 kg of catalyst. Efficient has RON 88 and 8%vol gas.
But when run the reality system, it can not get that target. Catalyst is very easy to deactivate.
Please help me to find some reasons.
 
Answers
20/12/2013 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Catalyst may not be suitable for the process and may need more active metals, You specified only Sn. Are there other metals? Sulfur and other contaminants like nitrogen present in naphtha could cause poisoning. Catalyst would have been quickly deactivated by coke. It is possible in absence of hydrogen and its circulation. Deactivation looks very fast needing catalyst regeneration
17/12/2013 A: Morgan Rodwell, Fluor Canada Limited, morgan.rodwell@fluor.com
I would be concerned about the distribution of the SnCl2 into the catalyst bed and the distribution of the FEED. It sounds like you are not getting activity on all of the catalyst. The bed depth may be too short to ensure good distribution on it's own.
Other concern would be contaminants in the feedstock that deactivate the catalyst, like sulfur or nitrogen species. However, it sounds like your problem is instantaneous, not something that develops over time, so the chloriding and distribution would be the first place I would look.