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