[ 2 0 1 6 I E A G H G C C S S u m m e r S c h o o l ]

C a r b o n D i o x i d e U t i l i z a t i o n

D r . D a v i d Wa s s e l l B D P S S e n i o r C h e m i s t

J u l y 2 0 , 2 0 1 6

2

Imagine an industrial chemical that: • Readily biodegrades.

• Is available in large quantities.

• Is cheap.

• Has tunable solvent properties.

• Can be used as a C1 chemical precursor.

• Is well understood.

• Has very low toxicity.

3

Rehabilitation of a maligned molecule

Geochemical and biogeochemical history:

• Early atmosphere consisted of nitrogen and carbon dioxide.

• Most carbon dioxide locked in sedimentary and

metamorphic rock (~80% as carbon).

• Some is dispersed as organic carbon in sedimentary rock

(biological activity) and unavailable.

• Very small remainder exists as CO2 (~0.001%) in the

atmosphere in equilibrium with carbonates in the ocean

(0.04%).

• Traces exist as biomass (0.0007%)

4

Biological background • Plants convert carbon dioxide and water to carbohydrates

using the sun as an energy source.

• CO2 fertilization is used extensively in the greenhouse industry.

• Estimates of the effect of CO2 fertilization on field crops range from no effect to up to 15% of the historical increase in yield (depending on who you believe).

• Carbon dioxide is released when food is metabolized.

• At CO2 concentrations below ~150 ppm, (C3) plant growth nearly ceases.

5

Safety and toxicity • Time weighted average (TWA) limit of 5000 ppm (7000 ppm

for NASA SMAC limits), 30000 ppm short term exposure limit (13000 NASA).

• Acute health effects noted above 10000 ppm, lowest concentration reported to cause death is 90000 ppm.

• Odourless, colourless, and non-flammable.

6

Physics

• Easily accessible liquid and supercritical region.

7

Chemistry

• Fully oxidized. • D∞h symmetry (linear). • Low reactivity, must be activated to react. • Can be used as a chemical feedstock.

8

Utilization

9

Some existing markets include

Decaffeination Drycleaning

Botanical Extractions Urea

Manufacture Horticulture

10

Some emerging markets include

• Polycarbonate synthesis • Dimethylcarbonate synthesis • Sabatier reaction/ reverse water gas shift • Accelerated mineralisation

Methanol synthesis

Electrochemical formic acid

synthesis

Dimethyl ether synthesis via

syngas

11

Utilisation Categories

These can be divided into the following broad categories:

• “Storage” (EOR and mineralisation).

• As solvent (botanicals, drycleaning, processing fluid).

• Fuels.

• Chemical precursors.

12

Storage

• Enhanced oil recovery • CO2 is used to flood oil formation. Approx. 90% is trapped

underground in pores.

• Mineralisation • The conversion of metal oxides and silicates to

carbonates. • Use of alkaline waste (slag, flyash, etc) most advanced. • E.g. cement curing (conversion of, primarily, calcium

hydroxide to calcium carbonate) can be accelerated by enriched carbon dioxide atmosphere.

13

Solvent

• Dry-cleaning fluid, parts degreaser.

• Botanical extracts.

• Textile dyeing and wood preservative impregnation

14

scCO2 as a solvent

• Solvent polarity is a function of pressure and temperature.

• Solute recovery is achieved by decompression.

• Fractionation can be achieved by successive pressure drops.

• The reverse process can be used to infuse wanted chemicals to substrates.

15

scCO2 as a process adjunct

• Can be used as a pre-process step on cellulose and lignins.

• Decompression disrupts biopolymer structure. • This allows much more efficient fermentation or

enzyme catalysis

16

Examples:

• One decaffeination processor treats 60,000 tonnes per annum.

• DyeCoo textile dyeing.

• Essential oil extraction. • Parts cleaning.

• Biowaste pre-processing.

17

Chemical Precursor

Fuels: • Methane synthesis.

• Dimethylether (DME) synthesis.

• Ethylene synthesis.

• Energy storage, not energy production.

18

Chemical Industry: • Methanol, ethylene, dimethylcarbonate, syngas.

• All require reduction of CO2.

• Can be produced by a combination of Sabatier, Fischer-

Tropsch, reverse water-gas shift, etc.

19

• Combination of water, energy, and carbon dioxide can reproduce most of the fuel and plastic industries.

• Current plans are to use Sabatier and RWGS reactions to produce methane and oxygen for Mars missions (NASA, SpaceX, etc.).

20

Reactions:

• Reverse water-gas shift reaction

• Sabatier

• Fisher-Tropsch

CO2 + H2 CO + H2O

CO2 + 4H2 CH4 + 2H2O

nCO+(2n+1)H2 CnH2n+2 + 2H2O

21

The use of Carbon dioxide in the chemical industry assumes a source of hydrogen:

• Currently most hydrogen is produced by steam reforming of methane.

• The other options include electrolytic reduction of water or thermal decomposition of water. Both require an energy source.

22

Utilisation Pathways

Multiple pathways for the utilization of CO2 • EOR, mineralisation.

• scCO2 as solvent.

• scCO2 as process adjunct.

• Potential use as fuel and chemical precursor

assuming chemical or electrochemical reduction of CO2.

23

Useful References

• “Accelerating the uptake of CCS: industrial use of captured carbon dioxide”. Global CCS Institute, Parsons Brinckerhoff, Dec. 20, 2011.

• Morais, A.R.C; da Costa Lopes, A. M.; Bogel-Łukasik, R*, “Carbon Dioxide in Biomass Processing: Contributions to the Green Biorefinery Concept”, Chem. Rev. 2015, 115, pp. 3−27.

• Styring, P.; Quadrelli, E. A.; Armstrong, K., “Carbon Dioxide Utilisation: Closing the Carbon Cycle”, Elsevier, Sep 24, 2015.

Q u e s t i o n s ?

24