713-665-7046

713-665-7046

Designing the CDU/VDU for Opportunity Crudes

 

Summary

New units for processing heavy crudes should not be designed using conventional practices or run length with be short, and product yields and quality poor.

Text

Opportunity  crudes  cost  less than  other  crudes  because they  are  more  difficult  to refine  into  gasoline  and  middle distillate.  Yet  there  is  a  perception that  profitability  will  improve simply  by  substituting  them  for more  expensive  feedstocks.  At times,  certain  crudes  sell  at  huge discounts.  This  may  be  when production  exceeds  the  industry’s ability  to  process  them,  whether  it is  for  short  periods  that  are  caused by unplanned shutdowns or longer periods  when  regional  logistics arise such as distribution constraints for  Canadian  bitumen.  Refiners tend  to  focus  on  conversion  units such  as  the  coker  or  hydrocracker, and  the  crude  and  vacuum  unit (CDU/VDU)  is  often  an  afterthought.  As  more  heavy  and extra-heavy  crudes  enter  the market, there will be more opportunity  for  refiners  to  run  them.  The question is whether it will be profitable  or  not. Will  lessons  learned  be incorporated  into  unit  designs  or will  refiners learn  only  through  the school of hard knocks? CDU/VDUs must  be  designed  or revamped  for opportunity crudes or there will be unscheduled  shutdowns,  poor product  yield  and  quality,  and maintenance  costs  much  higher
than anticipated.

Processing  opportunity  crudes  in high  blend  percentages  reliably  is different  from  running  common heavy  crudes  such  as  Arab  Heavy. Common  problems  encountered when  processing  extra-heavy opportunity  crudes  include  poor desalting,  which  often  results  in severe  atmospheric  crude  overhead system  corrosion,  including New units for processing heavy crudes should not be designed using conventional practices or run length will be short, and product yields and quality poor exchangers,  piping  and  vessels...

 

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Tags: CDU, VDU