Q & A > Question Details

In our refinery we have an alkylation unit with HF and in recent dates we have had many problems with the acid vaporizer of the HF regeneration column (acid leaks from the tubes). The tube bundle is monel 400 and the heating medium is tempered medium pressure steam. Do any of you have similar experiences and could you help us find the failure mechanism?

Thank you.
18/10/2019 A: Matthew Wojtowicz, Honeywell UOP, Matthew.Wojtowicz@gmail.com
If corrosion is the problem, generally bundle life can be increased by reducing the heating medium temperature (i.e. reducing steam temperature) or by reducing the vaporization percentage (i.e. reducing the vaporizer outlet temperature) in the exchanger. This loss in energy input to the rerun column must be made up by the stripping isobutane, or more acid will end up in the bottom of the column, increasing losses. Often times, limiting the vaporizer duty can limit the HF Alkylation unit’s throughput, so an economic decision must be made regarding the bundle life and replacement cost versus the cost of acid and/or loss of unit throughput. It is best to check with the process technology licensor for specific recommendations for your HF Unit design, such as UOP HF Alkylation technology.
14/10/2019 A: Keng Chung, Well Resources Inc., kengchung@hotmail.com
It is time to consider retrofitting HF with a non hazardous, non corrosive Ionikylation technology, see https://www.wellresources.ca/ionikylation