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(2016) Question 8: Do you have experience starting up an isomerization unit (an alumina chloride catalyst type) without first acidizing the reactor loop? What was the impact on catalyst activity?

Honeywell UOP strongly recommends that acidizing of the reactor circuit should be included in the commissioning and startup of a new grassroots or revamped Penex™ or of Butamer™ units (isomerization units with chlorided alumina catalyst). If not, the consequence can be a significant amount of catalyst deactivation, as well as possible corrosion in the reactor section of the unit. A recent experience in which the customer elected to NOT complete the dry out and acidizing of a new reactor section resulted in an estimated deactivation of 60 to 85% of the new catalyst load.
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(2016) Question 9: Describe your experience and application of advanced separation techniques, such as DWCs (dividing-wall columns), to reduce capital investment and operating expense.

At Valero, we actually have several dividing-wall column applications. We have four in aromatics recovery service and one in a sat(saturated)gas plant service. The towers in aromatic service have been in operation between three and six years, and the tower in the sat gas service has been in operation since early 2016. All towers are meeting their design expectations. The dividing -wall towers have several advantages relative to the traditional sequential column designs.
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(2018) Question 4: What are the requirements for a unit depressurization valve in isom unit using a chlorided alumina catalyst based? Do you require the depressurization valve to be operable from the console and/or emergency shutdown device (ESD) panel?

Axens recommends that in cases of emergency depressurization of the reactor circuit, the circuit fluid is depressurized into the product stabilizer with the light gases still being treated in the off-gas caustic scrubber before being sent to flare.
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(2018) Question 6: What are the catalyst or design considerations that you employ to repurpose isom units for other services, or to repurpose another type of unit into an isom unit?

With increasing quantities of lower octane naphthas reaching the gasoline pool and potential for higher octane demand in the finished stocks, the octane boost from isomerization units has grown in importance. While the installation of new units is ideal, many refineries have been looking at utilizing idled units or converting existing units to isomerization type operation.
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