Hydrocarbon Fouling of Reverse

Osmosis Membranes

Group 3 Senior Design Project

Fall 2012

Task: Hydrocarbon Removal

• Design cost-effective pretreatment system for

hydrocarbon fouling of a polymeric RO

membrane

• Must be demonstrable in applications where

200 ppm of hydrocarbons exist and must be

removed from industrial water

Design Considerations

• Hydrocarbon recipe is a 50/50 (by

volume) mixture of mineral spirits and

diesel (non-vegetable oil or ethanol

additive)

• The water sample is 3000ppm NaCl and

180ppm of the hydrocarbon mixture

What is Reverse Osmosis (RO)? • Desalination process used to treat

process wastewater/hydrocarbon

recovery water

• Apply pressure (enough to overcome

osmotic pressure) to feed water so that

it moves through a semi-permeable

membrane

• Removes ionic and molecular sized

substances

http://www.water-technology.net/projects/perth/perth4.html

http://www.sustainableplant.com/2012/04/make-the-most-of-reverse-

osmosis-membranes/

http://www.lenntech.com/membrane-fouling.htm

Potential Solutions

• Pre-treatment of influent

– Ultrafiltration

• clogging

– Biological treatment

• sludge disposal

– Mechanical Removal

• activated carbon

• Fouled Membrane Treatment – Chemical removal of hydrocarbons

• Expensive, destroys membrane, downtime

– Replace Membrane

Rice

http://www.scu.edu/profiles/images/green_technologies.jpg

http://www.ricehusk.com/content/menu_102/products

http://www.marksdailyapple.com/is-rice-unhealthy/

720 mil ton

158 mil ton

Rice Production

• United States:

20 billion lbs.

• Louisiana: 2.7

billion lbs.

http://www.menurice.com/all-about-

rice/meet-us-rice-farmers

http://www.usarice.com/doclib/188/219/367

7.PDF

Organic material and moisture 73.85%

Al2O3 1.23%

Fe2O3 1.28%

CaO 1.24%

MgO 0.21%

SiO2 22.11%

MnO2 0.07%

Content of Rice Husk (wt%)

a-cellulose 45.59%

Lignin 23.17%

D-xylose 18.45%

L-arabinose 6.88%

Methylglucuronic acid

3.44%

D-galactose 2.47%

Amount Organics present in RH (wt%)

Silica(SiO2) 87.59%

Aumina(Al2O3) 4.30%

Sulfur trioxide(SO3) 0.85%

Iron oxide(Fe2O3) 0.45%

Calcium oxide(CaO) 4.20%

Magnesium-oxide(MgO)

0.27%

Sodium oxide(Na2O)

0.73%

Potassium oxide(K2O)

1.59%

Amount Present in Rice Husk Ash (wt%)

Rice Husk ASH

• What is it

– Rice husk that have been combusted in an

oxygen deprived environment

• How we used it

– ASH has an affinity for hydrocarbon

• Why

– Sustainable use of waste byproduct

Ash Production in Bulk

• Limit the amount of Oxygen entering the

reaction during the burning of the rice

hulls

• Retains more volume

• Better Absorption

• More efficient use of the rice hulls

• Less cost

Ash Production in Bulk cont.

Standard for Measurement

Lab Standard based on 1 L

1L Deionized H2O

+

3,000mg NaCl

+

.24mL Hydrocarbon solution

GC Peaks

Calibration Curve

y = 177.58x + 282.4 R² = 0.98773

0

5000

10000

15000

20000

25000

30000

35000

0 20 40 60 80 100 120 140 160 180 200

GC

Pek A

rea

Concentration (mg/L)

• Used Langmuir Isotherm to approximate mass

of Ash needed for lab standard (~17g)

y = 4.9053x R² = 0.99607

0

100

200

300

400

500

600

700

800

0 20 40 60 80 100 120 140 160

Cs/C

e

Ce (mg/L)

Langmuir Isotherm

Physical Application of

Rice Hull Ash

– Direct application to LNAPL (manually on top)

• Determine ash affinity for hydrocarbons

– Ash as a simple filter

• Ash packed in cylinder

– Turbulent action utilizing density separation

• hydrocyclone

Prototype

Turbid Effluent

Cyclone – separation by density

Test Results

Full Scale (1,000 gpm)

What is the cost of this ash?

05

101520253035404550

Arkansas Louisiana California AverageSouthern

States

$/ton

4 Feb 2013 Rice Market News

What is the cost of this ash?

$1,460 per day for ash

$534,000 annually for ash

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400

Co

st (

$)

Miles

Transport of Rice Hulls Cost per Ton

2004

2012

2004: $1.45 vs. 2012: $1.76

http://www.bls.gov/data/inflation_calculator.htm

What is the cost of this ash?

$1,460 per day for ash

$534,000 annually for ash

+ $47,000 to transport from local source

+ $267,000 in operational costs (i.e. wages, etc.)

= $848,000 for an entire year

Cogeneration Power

• Rice hulls as a biomass: 3.66 kwh/kg

• Generation of power from biomass: 0.12

$/kwh

• Gain from burning: 0.44 $/kg

• Daily gain from kwh produced: $29,100

• Annual gain from kwh produced:

$10,600,000

Capital costs gains/losses

• Transformation of waste to use

• Recovers product and gains $700,000

in energy from burning hydrocarbons

• Neglecting facility operational costs, a

factor of 12.5 EROI

• Note with estimated costs and EROI of

6.8

Conclusion of Experiments • Filter design

– Great hydrocarbon removal

– not efficient and turbid effluent is problematic

• Cyclone design

– Good hydrocarbon removal

– Good mass separation

• Dispersed air floatation

– Combines best qualities of both designs

– Use of dispersed air increases hydrocarbon

removal

– Achieves goal of hydrocarbon removal

Special Thanks

• Dr. Malone - LSU C.E.

• Dr. Constant – LSU B.E.

• Dr. Theegala – LSU B.E.

• Dr. Dismukes – LSU E.C.E.

• David Hawley - Geosyntec

• Alex GC

• Adam Dassey

• Michael Cheatham