© Cemeg Ltd 2014


Cemeg


Additive Consultancy and Blend Optimisation


DIESEL FUEL COLD FLOW  : CEMEG TECHNICAL SERVICE

Request Papers:  TroubleShooting CFPP.pdf & Additive Selection.pdf


Blending to the CFPP specification is dependant on the fuel character and interaction with the additive.  CFPP can constrain blend formulations and regardless of dosages be impossible to achieve specification without changing the blend.  Narrow fractions and paraffinic feeds being the main factors increasing additive demand. The higher comonomer (VA) content polymers tend to give a performance advantage in less responsive fuels. However, the highest responding additive in a single set of samples is not always the best product for a refinery to stock, especially if only one additive can be stored on site.  Our paper Additive Selection.pdf describes the optimum selection procedures for different refinery scenarios.


Cemeg implement monitoring programmes with the objective of predicting difficult blend scenarios.  These involve predictive work from historical data and also routine sampling and trial testing of additives. This generates laboratory work, but at levels we consider justified by the importance and significant cost of Cold Flow applications.





Trouble-Shooting Cold Flow is usually Cemeg’s introduction to a refinery.  We normally find changes in the fuel character are causing the previously effective additives to fail.  These changes may be driven by many factors such as mechanical plant issues in distillation, or refining economics moving between operating modes.  A refinery maximising kerosene yield will tend to narrow the diesel fraction width,  conversely a plant maximising diesel may introduce higher boiling components, moving the interaction from the ‘narrow fraction’ to the ‘high boiling’ limit in the additive’s ‘window of operation’.  


If a fuel is untreatable or the additive is failing to match the fuel, then a solution is required over a short time frame.  Cemeg have a proven track record in helping refineries quickly diagnose problems and restore normal operation.  Our paper TroubleShooting CFPP.pdf lists the main factors to be checked.