our company has been contacted by a potential oil refiner (straight run); the client has received assay data for a the expected oil for which contract is being finalised. we have been asked to review the possibility and FEED services for a straight run refinery units based on the assay. so far so good.
the crux comes on the assay. it is sent by a major international oil producer; the assay report is a two page document, showing low probable and high probable cases. The assay is a simulated assay (my understanding is that it is the probable boil cuts based on the chromatograph analysis).
now while trying to input the data available on to a hysys simulation case, I have noted the following:
1) there is no definition that it is D86 analysis which is understandable as it is not based on actual D86 equipment
2) but I have seen simulated assays reported as D2887; but in this case it is also not possible, as the yield % are not midpoint values
3) more importantly I find it difficult to comprehend the meaning of these assay results ;
the overall crude characterestics are given as 0.817 gm/cc (42.1 api) while cut densities are reported quite differently.
3a) in the low probable case, the bulk density of the whole crude is reported as 0.41 gm/cc and 50 % is reported as recovered at 115 deg C (this makes the liquid very light condensate); and the C5-65 cut (the first cut) shows an yield of 2.2%; with upto C4s -light ends- are 1.76% and the cumulative becomes 3.96% while it is mentioned just as 3.1%; i
3b) subsequent individual cuts and cumulative cuts don't add up neatly; and overall distillation yield is reported 50% only (for such a light fluid) at 370 deg C
4a) in the high probable case the whole crude density values are all above 1.22 gm/cc and individual cuts all add up to 150% yield value.
before inputting these values in a simulator, I would like opinions and explanations from the forum members as to how to interpret these numbers
regards
neelakantan