Drag Reduction Efficiency of Red Algal Extracellular Polysaccharides

Yang He

Russell School of Chemical Engineering

Overview

• Industrial drag reducing agent(DRA) and drag reduction efficiency test

• Red algal polysaccharides

• Results

Drag Reducing Agents(DRA): Long chain polymer chemicals that when injectedinto a pipeline where the fluid is turbulent modifies the flow regime by reducingthe frictional pressure drop along the pipeline length

Algal polysaccharides used in this study

Red microalgae Porphyridium sp. polysaccharides (P. cruentum and P. aerugineum)

Red microalgae polysaccharide agarose(Agar)

Red microalgae Porphyridium sp. polysaccharides extraction procedure

Grow Porphyridium sp.

in the shaker/bioreactor

for weeks

Centrifuge the liquid to get the supernatant out

Add 0.05M NaCland 0.1% CPC into

supernatant and incubate in 40 °C

shaker for 24h

Wash with DDH2O in 40 °C shaker for 24hPrecipitate in 3 vols

cold ethanol

Solubilize in 2M CaCl2, agitate at 40 °C shaker for

24h

Tank

Pipe

Pump

Experimental settings

� Diameter: 1/2 in. copper

� Length: 8 ft

� Total volume: 40 L

� Pump capacity: 0.75 hp� Pump capacity: 0.75 hp

� Concentration: tested by phenol-sulfuric acid carbohydrates assay

� Reynolds: 27000 (flow rate 4.67 gal / min)

Drag in a pipe system calculation

Darcy-Weisbach equation

Generally definition of percentage drag reduction

Effect of Polysaccharide Concentration for Industrial Used Gums

15.0%

20.0%

25.0%

30.0%

% D

rag

Re

du

ctio

n

Xanthan gum

Guar gum

0.0%

5.0%

10.0%

0 20 40 60 80 100 120 140 160 180 200

% D

rag

Re

du

ctio

n

Concentration ppm

Effect of Polysaccharide Concentration for Red Microalgae Porphyridium cruentum.

15%

20%

25%

% D

rag

Re

du

ctio

n

0%

5%

10%

0 20 40 60 80 100

% D

rag

Re

du

ctio

n

Concentration (ppm)

Drag Efficiency Comparison of Red Algal Polysaccharides and industrial gums

15.0%

20.0%

25.0%

Dra

g r

ed

uct

ion

eff

icie

ncy

Drag Reduction Comparison @ 100 PPM

0.0%

5.0%

10.0%

xanthan guar Porph. Cruentum

Dra

g r

ed

uct

ion

eff

icie

ncy

Porphyridium aerugineumppm

Drag reduction efficiency

15 5.4%

15 6.5%

15 4.3%

Red Microalgae Porphyridium aerugineum Production & Drag Reduction Efficiency

15 5.6%

15 5%

* J. Ramus. 1972. The production of extracellular polysaccharide by the unicellular red alga porphyridium aerugineum. J. Phycol. 8, 97-111

Production of polysaccharide in stationary phase is about 4mg/L

Effect of Polysaccharide Concentration for Agar

0.00%

2.00%%

Dra

g R

ed

uct

ion

-2.00%

0.00%

-50 0 50 100 150 200 250

% D

rag

Re

du

ctio

n

Concentration (ppm)

Drag Efficiency Comparison of Red Algal Polysaccharide

10%

Dra

g r

ed

uct

ion

eff

ice

ncy

Drag Reduction of Red Algal Polysaccharides

0%

5%

15 ppm Porph. aerugineum 20 ppm Porph. Cruentum 120 ppm Agar

Dra

g r

ed

uct

ion

eff

ice

ncy

Chemical Structure of different polysaccharides

Red microalgae Porphyridium sp. polysaccharides

(P. cruentum and P. aerugineum)Red microalgae polysaccharide agarose (Agar)

Xanthan gumGuar gum

� Production of Prophyridium sp. Polysaccharides is limited

� Red microalgae Prophyridium sp. polysaccharides have the potential to be used as

Conclusion

� Red microalgae Prophyridium sp. polysaccharides have the potential to be used as DRAs but not all of the algal extracellular polysaccharides works

Summary

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

xanthan guar Porph. Cruentum

Dra

g r

ed

uct

ion

eff

icie

ncy

Drag Reduction Comparison @

100 PPM

0%

5%

10%

15 ppm Porph.

aerugineum

20 ppm Porph.

Cruentum

120 ppm Agar

Dra

g r

ed

uct

ion

eff

ice

ncy

Drag Reduction of Red Algal

Polysaccharides