Quantification of DRA in jet fuel

Rotary Evaporation with GPC detection Proposed ASTM Method

- Pipeline Drag Reducing Additive (DRA)

- Optimization of Rotary Evaporation with GPC detection

method

Overview

DRA molecular weights > 25 million Daltons (n and m >200,000)

DRA chemistry

* *n

m

MonomersLinear alpha olefin

Example of polymer chemistry

Poly(alphaolefin)Drag Reducing Additive

(DRA)

Drag reduction mechanism

DRA mitigates turbulent burst imposing long

range concerted axial motion

Flow

DRA

Local flow direction

high strain regions Valves, Pumps, Restrictions Sheared DRA 1 to 3 million Da

(not as effective, reinjection)

DRA > 25 million Da

Drag reduction can be thought of as a reduction in the frictional factor f % Drag

reduction

FLO MXC ppm0 10 20 30 40 50 60 70 80 90

1009080706050403020100

Fuel pipeline operations

FlowInterface Diesel

No inject. Buffer

Turbulent Flow

- Flat velocity profile

- Low interface volume

Laminar Flow

- Faster center velocity

- Large interface volume

Potential DRA contamination sources

Jet fuel(DRA not allowed)

2.) Chemical dispersion No

3.) Pipeline operational mistakes Yes

4.) DRA injector leaks Yes

1.) Use of drag reducers increases interface size Mitigated

Risk

Verbal reports of DRA contamination in jet fuel

DRA impacts jet fuel performance (taken from Stan Seto CRC Report 642) Diminishing fuel spray angle and atomization capability @ 8.8 - 32 ppm

A significant loss in engine start capability @ 8.8 and 32 ppm

The report concluded that DRA was not acceptable for use in aviation fuel

The actual safe limit has never been identified

TF is targeted developing methods with a limit of detection of 50 ppb which is

considered low level contamination except for highly active contaminants like

copper

DRA monitoring industry wide

Analytical method background

Principles of Gel Permeation Chromatography (GPC)

Time = 0

Flow

Detection

Elution time

Area proportional to concentration

Related to molecules size or MW

1 2 3 and so on…

Detector (RI, ELSD ...)

Jet fuel molecules

DRA polymer

Stationary phase Mobile phase not shown

Rotovap Concentrating with GPC Detection

Original proposed method

Jet fuel (W1 ≈ 400g)

Backfill w/THFFilter

Sample Prep

5-8hr

Concentrated DRA sample

(W2 ≈ 2g)

Rotovap (130oC)

Overnight

Pierce Reacti-therm (120oC) Sample for

GPC

Can detect to 50 ppb Sound method but need something simpler for widespread implementation

Data workup

integrated DRA area Determine PPM

Concentration of DRA in jet fuel = (Determined PPM) x

(W2/W1)

ELSD

GPCdivert flow from ELSD

after DRA elutes GPC column PL type Mixed D

10μ particle size

THF

Inject 200μl

Waste

3 21

Heptane

THF

Impact of mobile phase

NO, significant loss in ELSD detection sensitivity with heptane

Original Proposed Method

Sample conc.

~200x (Rotovap)

GPC column

5µ PL Mixed D

# of columns

3

Mobile phase

THF Heptane

Detector ELSD

Detection limit

0.05 ppm

Can we use heptane instead of THF in the proposed method?

~2 ppm DRA samples

Baker Hughes GPC setup

Original Proposed method

Baker Hughes

Sample conc.

~200x (Rotovap)

~5x ~200x(Dry bath Rotovap @

EM)

GPC column

5µ PL Mixed D

5μ PL Mixed C

# of columns

3 2

Mobile phase

THF THF

Detector ELSD ELSD

Detection limit

0.05 ppm ~1 ppm

No improvement found over original proposed method with respect to detection sensitivity

FLO_XS

LSU

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

Minutes

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00

FLO_XS

LSU

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

Minutes

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00

~ 2.5 ppm DRA sample

Can we combine rotovap concentration with Baker Hughes GPC?

Original jet fuel sample with 50 ppb DRA 10.7 ppm after concentrating

Magellan Midstream Partners GPC setup

Original proposed method

Magellan Midstream Partners

Sample conc.

~200x (Rotovap)

None ~200x (Rotovap @

EM)

GPC column

5µ PL Mixed D

10µ PL Gel 104 Å

# of columns

3 1

Mobile phase

THF Heptane

Detector ELSD RI

Detection limit

0.05 ppm ~1 ppm

Can we combine rotovap concentration with MMP GPC?

Yes. Results are very encouraging, GPC simplified enormously!

DRA’s permeating

DRA’s totally excluded

Bigger DRA’s excludedSmaller DRA’s permeate

Simplifications applied to ASTM draft method

Original proposed method

Magellan Midstream Partners

ASTM DraftMethod

(Basic GPC)

Sample conc.

~200x (Roto.)

none ~200x (Roto.)

GPC Column

5µ PL Mixed D

10µ PL Gel <104 Å

10µ PL Gel 104 Å

# of columns

3 1 1

Mobile Phase

THF Heptane Heptane

Detector ELSD RI RI

Detection limit

0.05 ppm ~1 ppm 0.05 ppm Maintained 50 ppb detection limit

1) Requires less columns less run time 2) Better separation no overnight evap.3) Sharper peak RI detections is viable

Key to getting down to ppb levels

More acceptable

Common GPC detection

Ruggedness tests

Sample 1 2 3

Initial weight sample 399.36 399.45 398.93

Weight of concentrate 1.59 2.26 2.46

ppm from GPC 13.1 10.3 7.1

ppb after correcting for concentration 52.2 58.3 43.8

y = 335.57x

R2 = 0.9999

0

5000

10000

15000

20000

25000

30000

35000

40000

0 20 40 60 80 100 120

ppm DRA

Are

a

S/N > 40

Calibration direct blend of DRA @ 2, 4, 10, 20, 100ppm in jet fuel

Results for 3 Jet fuel samples with 50 ppb DRA

RI GPC104A

Heptane

1

Jet fuel (W1 ≈ 400g)

Sample Prep

5-8hr

Concentrated DRA sample

(W2 ≈ 2g)

Rotovap (130oC)

Example result (#2)

-0.03

0.01

0.05

0.09

0.13

0 1 2 3 4 5 6Time (minutess)

RI

GPC column, 10m particles with 500Å pore size. Sample analyzed contained 2.9 ppm DRA in jet fuel (after rotovap concentrating a 50 ppb DRA in jet fuel sample) Chromatogram example exhibits a DRA signal that satisfies the >10 S/N. After rotovap concentrating a 400g sample containing 50 ppb DRA the final weight of the concentrate should be ~ 7g or less (2.9 ppm or greater concentrate) for this GPC apparatus

Height of high frequency peak to peak noise

10x noiseS/N = 13.7

Limits to quantifying the minimum DRA concentration

-0.03-0.01

0.010.03

0.050.07

0.090.11

0.130.15

0 1 2 3 4 5 6

Time (minutess)

RI

50 ppb sheared gel

50 ppb sheared dispersed

50 ppb unsheared gel

Typical LOQ requires the S/N ratio to be > 10 which is satisfied for sheared DRA (gel and dispersed). Unsheared exhibits less sensitivity but is above the level of detection (LOD) which typically requires the S/N ratio to be > 2

Tests with different DRA types

Description Gel type FLO XS Dispersed type FLO MXC

Sheared/Unsheared sheared unsheared sheared

Wt. of Sample before/after Rotovaping

396.37g/6.96g

396.37g/4.14g

396.54g/7.74g

396.29g/5.14g

Concentrated DRA conc.

2.9 ppm 4.9 ppm 1.8 ppm 4.3 ppm

Calculated conc. DRA of Original Sample

50.9 ppb 51.2 ppb 35.1 ppb 55.8 ppb

S/N 13.7 15.7 5.5 18.9

-0.01

0.09

0.19

0.29

0.39

0.49

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Time (min)

RI (

mv)

Tests with different GPC column article pore size

Pore size MW range Typical materials PL gel part # Excluded

50Å up to 2000 Jet fuel molecules 1110-6115

100Å up to 4000 1110-6120

500Å 500-30,000 1110-6125

10^3Å 500-60,000 1110-6130

10^4Å 10,000-600,000 1110-6140

10^5Å 60,000-2,000,000 Sheared DRA 1110-6150

10^6Å 600,000-10,000,000 Sheared DRA 1110-6160

~25,000,000 DRA

10ppm DRA sheared, gel type in Jet fuel (calibration sample, no rotovaping)

DRA & Sheared DRA

excluded

Results are similar for all pore sizes < 10Å. Tests include 50Å, 500Å and 104Å

w/ 50Å particle pore size

-0.04

0.06

0.16

0.26

0.36

0.46

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Time (minutes)

RI

Concentration (ppm) Area Peak height S/N

50ppb Concentrated sample 10.3 3.65 0.345 41.6

Calibration sample 10.0 3.41 0.340 67.9

RI DRA signal response is similar

Calibration samples vs. concentrated samples

Does Stadis® 450 cause measurement interference?

-0.03

-0.01

0.01

0.03

0.05

0.07

0.09

0.11

0.13

0.15

0 1 2 3 4 5 6 7

Time (minutess)

RI

50 ppb sheared gel

5ppm Stadis 450

Both samples concentrated on a

rotovap

Stadis® 450 MSDS indicates up to 40% trade secret polymer No interference observed

Conclusion

Recent efforts were placed on optimizing the DRA quantification method employing rotary evaporation with GPC detection

TF was successful in making many improvements making the method more deployable

Quantification to 50 ppb appears likely with readily available apparatus and acceptable solvents Method works with both types of DRA; suspension and gel Method works with both sheared and unsheared DRA

Slightly less sensitive for unsheared Proposed ASTM draft method has been prepared

Next steps Need to progress to a round robin GPC hardware is not limited to the basic apparatus described in the method. All

GPC configurations where the DRA peak signal/noise is >10 are acceptable to be used in the RR

Thanks for your data contribution

Nagesh Kommareddi Baker Hughes Chuck Haber Magellan Midstream partners

Patrick Mollere IntertekElisa Redfield Intertek

Thank You

2 3 4 5 6 7

Appendix

Most mixed columns looks to permeate sheared DRA

From PL website