Info

CEFIC, 2000

Dow Public Report 2002

Figure 10.2 Historical energy efficiency in the European chemical industry.

Olefins (ethylene, propylene)

AH

•J

10

15

OJ

t 5

0

U

High energy consumption and CO2 emission

Oil feedstock

High energy consumption and CO2 emission

Low energy consumption and C02 emission

Polyolefins (polyethylene and polypropylene)

Low energy consumption and C02 emission

Oxygenates (ethylene and propylene oxides)

Figure 10.3 Example of material and energy efficiency in the current crude-oil-based chemistry.

10.1.2 Feedstock of the Future

Three generic types of alternative feedstock to crude oil can be exploited as a carbon source for the chemical industry:

• Fossil feedstock not exploited today

• Renewable feedstock

• Atmospheric CO2

Methane is a fossil feedstock of potential interest to the chemical industry. Methane is to be found as an unexploited (so-called stranded gas) stream from

C02 Feedstockhttp://greenwood.cr.usgs.gov/energy/Work(Energy/DDS 60)."/>
Figure 10.4 Feedstocks in the Future. (From U.S. Geological Survey. World Petroleum Assessment 2000. http://greenwood.cr.usgs.gov/energy/Work(Energy/DDS 60).

crude oil extraction or in large reserve quantities (see Figure 10.4) well distributed across the world.

Renewable resources, which are by definition homogeneously distributed across the world, represent another potential feedstock of choice for the chemical industry. Renewable resources are essentially made of carbohydrates (cellulose, hemicellulose, starch), of lignin, and of a small part of vegetable oils (see Figure 10.5). They present the advantage as simultaneously a potential source of carbon and a CO2 sink through photosynthesis so that the impact of their exploitation on climate change (green house gas effect) can be regarded as neutral in the long run.

The total amount of renewable resources available around the world amounts to 170 GT/y (see Figure 10.6). Among them, 4.6 GT/y equivalent carbon are left in the fields as agricultural residues, while the world chemical industry currently consumes around 0.6 GT/y equivalent carbon (10% of the total current world

□ Carbohydrates (cellulose, starch, sugar)

Figure 10.5 Renewable resources split.

Global renewable resources Total use: 10-30% Total available: 170 GT/y

Fossil resources Total use: 7.3 GT/y (oil equiv.) Total available: 850 GTcoal 120,000 bill. m3 gas 135 GT oil

Biomass residues from agriculture cultivation and harvesting 4.6 GT/y (Carbon equivalents)

Oil Demand Chemistry

Global chemical Industry 0.664 GT/y oil equivalents 0.569 GT/y carbon equivalent

http://bioenergy.orni.gov/faqs/ FEMS Microbioi.Rev.1992,103, 355 Shell Venster 2002

Global chemical Industry 0.664 GT/y oil equivalents 0.569 GT/y carbon equivalent

Figure 10.6 Renewable resources, an alternative?

crude oil consumption). These numbers show that stranded methane and/or biomass residues, as well as the freely available atmospheric CO2, could theoretically supply enough carbon to replace crude oil and feed the growing world demand for chemicals while diminishing associated CO2 emissions. An additional benefit would be that the exploitation of these potential alternative carbon sources for chemistry would not compete with the carbon needs and associated land area required to feed humans and cattle. The exploitation of these three potential carbon sources is, however, facing very significant technology barriers, preventing their large-scale industrial exploitation in the short term.

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