Debottlenecking Catalytic Reformers

Catalytic reformers are another unit which can be debottlenecked beyond their design capacity. Improvements in catalyst activity and dense loading technology have allowed the reactors to handle higher charge rates. The downstream fractionation equipment’s capacity must be increased to keep pace. One such tower is the reformate stabilizer. Improvements in fractionation capacity can be made by installing packing as discussed for FCCU Main fractionators. Fractionation capacity gains can also be achieved by installing high capacity trays. Fractionation capacity increase may then cause the reboiler or overhead condenser to be the limiting item. If so, replacing the exchanger bundle with an extended surface bundle can lead to attractive payouts. In one such example, the steam reboiler was flux limited. Replacing the reboiler bundle with an extended surface bundle increased the reboiler area. Since the shell side had the limiting heat transfer coefficient, the results were dramatic. The tower capacity increased by over 25% for just the cost of a $15,000 exchanger bundle.

Extended surface tubes can increase many other services such as overhead condensers. Extended surface tubes are especially applicable to services in which the shell side has the limiting heat transfer coefficient since only the shell side area is increased. Remember to account for the smaller tube ID’s and hence higher pressure drops.