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Is it technically viable to inject sweet LPG ex CDU in reformate rundown (from bimetallic fixed bed reforming unit) with the sole purpose to increase reformate's RVP and RONC keeping in view that the reforming catalyst is nearing end of run and cannot meet the target sverity RONC? what are the repercussions?
 
Answers
24/02/2013 A: Sabapathi RATHINA, KNPC, k.sabapathi@gmail.com
it is possible to use neat sweet butane , LPG from crude unit has c3 which will increase vapour pressure to high level and it is not sweet
19/10/2010 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Long time back in seventies, some of the refiners tried to put about 3 % of C4 hydrocarbon to enhance octane. However such high content of C4 is not possible now due to RVP problem as they have about 52 psi RVP C4 have octane number of about 93.
13/10/2010 A: Lindsay McRae, Pall Corporation, Lindsay_McRae@pall.com
Not really viable. If you add LPG to reformate, the LPG will just be removed by the stabillisation column which is there to remove light ends (FG and LPG) to ensure reformate RVP maintains within spec. (Light ends must be removed to meet RVP spec plus also for storage tranportation safety reasons also).
In fact, when reformer stabilisation column is sometimes fouled by ammonium chloride coming with reformate from the reformate splitter, not reaching RVP specs because of column fouling and inefficiency can be a real issue and most refiners employ periodic water wash or a ammonium chloride removal filter on the feed to the stabilisation column to ensure stabilizer column is performing properly otherwise RVP of reformate would be off spec. (Pall Corp has some very nice success removing ammonium chloride from reformate on the stripper feed to minimise or eliminate need for water washing the stabilisation column). You run same risk of being off spec for RVP if you add LPG to reformate rundown so I'd not really endorse it.
13/10/2010 A: keith bowers, B and B Consulting, kebowers47@gmail.com
1) Propane is not good as motor gasoline--leads to vapor locking.
2) Octane number of mixed C4s from crude distillation is highly variable and dependent of the particular crude
3) The risk is hitting RVP and V/l20 limits and low octane due to C4s source.
13/10/2010 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Yes, it is technically feasible. From an overall view, it is like adjusting the RVP of the gasoline blend with propane, butane, or pentane. Compare the economics of the options by running your LP model for several scenarios.
13/10/2010 A: RENE AGA, SECOT, renelaga@telefonica.net
Depends on exact location of injection point, if LPG is sweet or desulfurized, stabilizer design and operation, required RONC, reformate pumps NPSH, etc.