Remediation of Crude Oil

Impacted Soils with Electron Beam

Irradiation

John Lassalle, Marco Martinez, Thomas Thompson, Kenneth Briggs, Harika Damarla, Craig Evangelista

Andrea Strzelec, David Staack

(Mechanical Engineering Texas A&M University, College Station, TX, USA)

Paul Bireta, Deyuan Kong, Thomas Hoelen, and Gabriel Sabadel

(Chevron)

1

A15-03

Motivation and

Objectives• Pollution of soils by heavy hydrocarbons is a major global environmental issue [1].

• Light Crude Oil – very mobile, bioremediate or weather away

• Very Heavy Oil – asphalt – immobile & acceptable

• Mid – Heavy Oil – don’t weather or bioremediate easily, moderate mobility, nuisance

• Remediation technologies must be fast, efficient, and economical at large scales

Objectives:

• Show proof of concept (TPH reductions to <1%)

• Impact of test parameters such as dosage

• Design of experiment setup

Niger River Delta [P1] Picture of Rock Bay Crude Oil

Remediation Site

2

Background

1. TPH = Total petroleum hydrocarbonMeasure of hydrocarbon (C6 thru C40) content in the soil.

Initial 3% - 5% Oil w/w

Goal (industrial) < 1%

Goal (non-industrial) < 0.15%

2. Typical Thermal & Energetic Removal MethodsDirect Heating - (flame on soil – heat to 500oC)

Indirect Heating – kiln drying (heat to 500oC)

Oxidation & Combustion – occurs in direct heating

Pyrolysis – occurs in high temperature kiln drying (inert gas)

3

Combustion

Pyrolysis

Conceptual e-Beam Process Overview Schematic

Excavation

Crushing &

Sizing

Conveyor

E-beam Processing

(mobile facility brought to site)

Gas Treatment / Air

Quality Control

Condensation of

desorbed vaporsTreated Soil

Water

Oil

Stock-

piling

Conveyor

Backfill with

Treated Soil

0.5 – 1 MW,

10 MeV

Electron Beam

Soil stays on site

Radiation

Shielding

Necessary only

when beam is

on. No residual

radiation.

4Soil Amendments

Why e-Beam?

• Advantages:– Higher rate of energy

addition than all other

energetic methods

– Production of char (fixed

carbon with potential

benefits for soil health)

5

0

100

200

300

400

500

-5 5 15 25

Tem

pera

ture

[°C

]

Time [min]

Soil Temperature-All Treatments

Industrial ThermalDesorption

Pyrolysis

Electron Beam

Held for 200 min

- Radiation chemistry speeds up pyrolysis cracks (easier to remove) or

polymerizes (reduces mobility) some medium-heavy hydrocarbons.

- Oils can be recovered from the soils

- Volumetric heating simplifies material handling, potentially enables

separation of liquid crude oil.

• Disadvantages:• Higher specific energy requirements (x2) than thermal methods

• Need radiation shielding during operation

• Penetration depth

E-beam processing facility concept

6

• Trailer mounted portable ebeam.

• On site, ex-situ

• Shown below is a single 800 kW, 8 MeV beam (Rhodotron)

• 100 CY / day, 10 ft/min feed, 8 second residence time

6

~70ft

Top ¼ of soil exits. Bottom ¾

captures residual heat and

dries input soil prior to ebeam

to ~10% water content.

Experimental Methods

• Experimental configurations

– Small batch 100g preliminary experiments

– Stationary large batches for dose matching

– Conveyed 3 kg samples (1 to 5 inches/minute)

• Various Soils Tested

– Synthetic Manufactured Mixtures (crude + dirt)

– Field Attained Soils (GSC1AOS, GSI14RD, BTSludge)

– Benchmark Soils (BM1, BM2, TX1)

• Dose ranges from 200 to 2500 kJ/kg at 6-10 kGy/s.

30s to 6 min residence time for irradiation.

• UV-Vis Absorption, Colorimetry for screening tests, Gas chromatography, Lancaster Labs for Third Party evaluation of TPH, TPO/TPD (fixed and mobile carbon).

7

Video of Processing

8

Still from Video

9

Processing Results TPH

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

TPH

(%

mas

s)

Dosage (kGy)

GSC1AOS

GSI14RD

BM1

BM2

DCM extracted PH

Increasing dose

10

Max Temperature vs. Energy Input

11

TPH ResultsGSC1AOS Soil

0

2000

4000

6000

8000

10000

12000

0 5 10 15 20 25 30 35 40

mg/

kg in

so

il sa

mp

le

~ Carbon Number

GSC1AOS 1100 kGy

GSC1AOS 720 kGy

GSC1AOS 0 kGy

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

0 5 10 15 20 25 30 35 40

% F

ract

ion

of

TPH

~ Carbon Number

GSC1AOS 1100 kGyGSC1AOS 720 kGyGSC1AOS 0 kGy

• TPH decreases with dosage

in the DRO and ORO ranges.

• GRO increases w/ dosage

• Maximum reduction: 9.1% →0.5%

• Thermal effects more

dominant at high doses.

Large increase in GROs

for highest dose

Non-thermal processing

Proportional removal of heavier fractions

No preferential removal

12

Treatment Cross SectionHeavily treated

moderately

treated

Got oily from

condensation

Still clean

Unaffected

SJV Soil

8.02 cm

1 cm

2 cm

3 cm

4 cm

13

TPD / TPO Analysis

(a) is TPO (incineration) comparison for untreated and treated,

shows that there is less combustible material in the treated sample.

(b) is TPD+O (volatilization) comparison for untreated and treated

samples, shows that there is much less volatile content on the treated

than the untreated sample, and the only volatile content that is there

is 'heavy'. (c) is the TPD+O then TPO (volatilization then

incineration) for the untreated and treated samples.

There is considerably more fixed carbon

in the treated sample as compared to the

untreated. However there is over all less

carbon. This indicates that the treatment

has volatilized a portion of the

hydrocarbons and converted some of the

hydrocarbons to char.

TPD TPO

MS TOTAL

CARBON

DESORBABLE

CARBON

FIXED

CARBON

14

Competitive Economics ($/CY)

15

Industrial Thermal Desorption is exiting / completing technology

Economic comparison cannot only consider energy requirements

Case study 100 CY/day, 6 mos.

e-beamdirect

thermal

Energy cost processing 33 19

Capital cost energy addition 35 20

Capital cost exhaust handling 5 20

Energy cost exhaust handling 1 5

Material excavation and loading 32 30

Site setup and security 7 4

Site setup and security 7 4

Post treatment pH amendment 1 4

Post treatment organic matter amendment 0 4

Post treatment nutrient amendment 5 5

Condensed Hydrocarbon (30% recovery) value -4 0

Soil amendment value -2 0

Total 113 111

Summary - Electron Beam Remediation of Soils

Proof of Concept– Benchmark and field attained soils successfully tested. Can extinguish the environmental liability (<1% TPH),

conceivably onsite.

– TPH can be reduced to <1% for 500 to 1000 kJ/kg increasing with initial contamination 1.6% to 9.1%.

Mechanisms: Analysis of hydrocarbon distribution indicates

1) Thermal Desorption effect

2) Low temperature & rapid pyrolysis effects (Char formation)

2) additional non-thermal process characteristics

i) electron beam initiated cracking and production of GRO

ii) low temperature Char formation by e-beam radicals

iii) proportional removal of DRO and ORO components

• Electron beam is safe (not a radiation source) when off, and shield-able with site materials.

• Other Factors: Fines & Exhaust Handling, Soil Amendments, No upper limit of TPH contamination.

• Progressing toward industrial scales– Beam & Treatment profiles

– Laboratory scale conveying systems

– Future testing at industrial rates in 10 MeV, 100 kGy/s facility 16

Thanks for your attention

Thanks to the National Center for Electron Beam

Research at Texas A&M University for allowing us to do

research on novel processing technologies

Thanks to Chevron for sponsoring this research

17

Hydrocarbon Content vs. Energy Input

0

0.5

1

1.5

2

2.5

0 500 1000 1500 2000 2500

Hyd

rocarb

on

Co

nte

nt

fro

m

Co

lori

metr

y [

% m

ass]

Specific Energy Input [kJ/kg], Dose [kGy]

19-Feb

12-Jan Moist

12-Jan Dry

31-Mar

29-Jul

3-Sep

15-Oct

27-Oct

Untreated

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Results-Dry Section

66

Wet Dry

51 4 876

1:10 1:40 1:80 1:160 TC 5 TC 6 TC 7 TC 8

670 kGy 680 680 600

2.28% 0.57% 0.285% 0.1425% ~0.75% ~0.5% ~0.3% ~0.75%

2.75” 8.25” 5.5” 2.75” 3” 2.875”

Max temperature higher for TC 7 than TC

5 despite same dose, suggesting heating

by adjacent soil. The soil near TC 7 also

appears to have a lower TPH than the soil

near TC 6. 0

100

200

300

400

500

600

0 200 400 600 800 1000

Tem

pera

ture

(°C

)

Time (s)

Thermocouple Data for Dry Section Test

Thermocouple 7

Thermocouple 8

Thermocouple 1

Thermocouple 4

Thermocouple 6

Thermocouple 5

Beam Motion

19

Specific Energy Cost Comparison

2

0

• Industrial Thermal Desorption (TPH < 0.2%)

– For cp~1.5 kJ/kg-°C and ∆T~420°C (from

experiment in Tube Furnace)

– Specific Energy Input = 630 kJ/kg

– ηthermal ~ 50% losses to environment from

chemical energy conversion to direct heating

(specification from Vulcan – TDU

manufacturer)

– Specific Energy Input = 1260 kJthermal/kgsoil

• e-beam (TPH < 0.2%)

– For Dose, D ≈ 650 kGy = 650 kJ/kg

– η= 60% e-beam generator efficiency (from

MEVEX – e-beam manufacturer)

– Specific Energy Input =1080 kJelecrtric/kgsoil

– Electrical Energy Cost (~ 2 kJthermal/kJelectric)

– Specific Energy Input = 2160 kJthermal/kgsoil

• Pyrolysis (TPH < 0.2%)

– ITD + hold time (energy use during hold is

configuration dependent 90 kJ/kg, ~5 CY

system)

– Specific Energy Input = 720 kJ/kg

– ηthermal ~ 40% from chemical energy due to

indirect heating

(specification from Vulcan – TDU

manufacturer)

– Specific Energy Input = 1800 kJthermal/kgsoil

• Ozone (target TPH not achieved independently)

– 1 kgozone / kgTPH,

– 10 kW-hr / kgozone,

– 900 kJelectric/kgsoil

– Specific Energy Input = 1800 kJthermal/kgsoil)

Soil Analysis

3

4

5

6

7

8

9

10

11

pHPyrolysis

Electron Beam

Industrial Thermal Desorption

Background

Untreated

0

100

200

300

400

Conductivity (μmho/cm)Pyrolysis

Electron Beam

Industrial Thermal Desorption

Background

Untreated

0%

50%

100%

150%

200%

250%

NO3N P K Ca Mg S Na Fe Zn Mn Cu B

Micronutrient Content ( BG normalized)

Pyrolysis

Electron Beam

Industrial Thermal Desorption

Background

21