AbstractHeat integration of conventional crude fractionation by use of a single pre-flash unit has shown to be less
energy efficient than conventional units alone when maintaining the same product yield. However, there is a reduction in the heat requirement when the flow rate of gas oil is reduced. Marginal improvements have been shown for heavy crude fractionation while maintaining high gas oil yield.
This work shows the results of use of multiple pre-flash units in several configurations. The heat integration of conventional units with multiple pre-flash units is analyzed using both light and heavy crude fractionation and compared to purely conventional units.
A new technology was proposed and its economic advantages are highlighted.
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PRE-FLASH CRUDE FRACTIONATION*Jonathan Peters** and Miguel Bagajewicz
University of OklahomaSchool of Chemical, Biological, and Materials Engineering
(*) This work was done as part of the capstone Chemical Engineering class at the University of Oklahoma
(**) Capstone Undergraduate students
Conventional
One Pre-flash
2 Pre-flashes
4 Pre-flashes
New Design (Details unavailable to public at this time)
conv. tray-10 tray-15 tray-20 tray-25 2 flash 4 flash new design0
20
40
60
80
100
120
Flow Rates (m3/hr.)
conv. tray-10 tray-15 tray-20 tray-25 2 flash 4 flash new design0
50
100
150
200
250
300
Flow Rates (m3/hr.)
Naphtha
Kerosene
Diesel
Gas Oil
Residue
Product Yield Heavy CrudeLight Crude
conv. tray-10 tray-15 tray-20 tray-25 2 flash 4 flash new design53
58
63
68
73
78
83Min. Heat Utility (MW)
conv. tray-10 tray-15 tray-20 tray-25 2 flash 4 flash new design53
58
63
68
73
78
83
Min. Heat Utility (MW)
Energy ConsumptionLight Crude Heavy Crude
Specifications UsedNaphtha 182Kerosene 271
Diesel 327Gas Oil 410Residue 820
Light Crude 95% D-86 Points (oC)Naphtha 182Kerosene 271
Diesel 327Gas Oil 390Residue 1220
Heavy Crude 95% D-86 Points (oC)
Naphtha-Kerosene 16.7Kerosene-Diesel 0
Diesel-Gas oil -2.9
Light Crude Gaps (oC)Naphtha-Kerosene 30.8
Kerosene-Diesel 4.4Diesel-Gas oil -6.6
Heavy Crude Gaps (oC)
Process Utility Cost Increase Profit Increase Gross Profit Increase1 flash tray-15 -$690,000 -$17,220,000 -$16,530,000
2 flash $3,280,000 -$19,520,000 -$22,790,0004 flash $7,790,000 -$395,350,000 -$403,150,000
new design -$1,980,000 -$14,270,000 -$12,290,000
Process Utility Cost Increase Profit Increase Gross Profit Increase1 flash tray-15 $2,120,000 -$4,310,000 -$6,430,000
2 flash $2,580,000 -$3,080,000 -$5,660,0004 flash $2,490,000 -$4,400,000 -$6,890,000
new design -$1,110,000 $7,160,000 $8,270,000
Light Crude Heavy CrudeEconomics
ConclusionMultiple pre-flashing increases the minimum heat utility, residue yield, and reduces gas oil yield. There is no profit increase with
multiple pre-flash. The new design shows noticeable energy improvement and gas oil recovery from conventional distillation (heavy crude only). Further studies are warranted. The new design yields a profit increase of $7 million per year for a heavy crude and negative values for a light crude.
Pre-Flash Configurations have higher consumption Our Novel Technology exhibits lower consumption
All Pre-flash cases have lower AGO yield for light crude Our Novel Technology exhibits higher AGO for the heavy crude
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