Q & A > Question Details
The chloriding agent used in fixed bed semiregenerative platforming unit is TCE mixed with platformate to be injected in the system. Is there any issue with mixing it with the run down platformate to the catalyst. Another question, what are the factors to be considered when changing the chloriding agent for example PERC ? Is there any impact?
21/11/2017 A: Patrick Bullen, UOP, patrick.bullen@uop.com
The previous answer are good guidance. UOP prefers using PERC for UOP catalyst as it has a lower decomposition temperature compared to TCE. Please contact you local UOP Regional Service Manager for more discussion on this topic.
Login to the UOP Customer Portal www.AccessUOP.com to explore our Knowledge Base, Frequently Asked Questions, Tools and more. Not a portal member, click on Registration to create your user credentials.
18/11/2017 A: Peter Marsh, XBP Refining Consultants Ltd, peter.marsh@xbprefining.co.uk
For a semi-regen platforming unit, chloriding agents are used in normal operation to maintain chloride on catalyst and during catalyst regeneration to aid platinum redispersion.
TCE has a different molecular weight (131.5) and liquid density (1.42 kg/l @ 20 Deg. C) to other chloriding agents. For example, PERC has a molecular weight of 166 and a density of 1.62 kg/l @ 20 Deg. C. So injection rates will be different to achieve the same level of chloride on catalyst. Health hazards, toxicity and handling precautions for TCE and PERC are similar so chloriding agent selection should be based on cost per kg of chloride rather than cost per litre of agent.
Regarding use of a carrier liquid in normal operation, platformer feed may be a better choice than platformate as this would minimise the risk of polynuclear aromatic compound formation in the reactors which may affect platformate product colour. Use of hydrocarbon carrier liquid during catalyst regeneration is not recommended for several reasons; it will affect oxygen consumption and temperature profile in the reactors and if elevated oxygen concentrations are used there is also a risk that any residual platformer feed or platformate carrier fluid in the injection quill could auto-ignite causing localised high temperatures and possible rupture of the chloride injection nozzle on the process piping. A better solution would be to pump small amounts of chloriding agent intermittently as required and then immediately sweep the chloride agent injection piping with high pressure nitrogen.
17/11/2017 A: Krishna Rao Pulugurti, Retired/Consultant, pkrao2012@yahoo.com
Catalyst supplier will advise you. Generally i ppm chloride in recycle gas is the norm.