Fossil oils

The most important types of fossil oils are extracted directly from subterranean reservoirs, as crude oil and natural gas. Fossil oils can also be extracted from coal or from oliferous slate or clay.

The refining process is the starting point for many products used in the building industry (Table 9.1). Heavy distillates including tar and asphalt are used directly, mostly for making roofs and joints watertight. Other, more refined, products provide raw materials for a whole spectrum of commodities: glues, waxes and solvents for paints. Fossil oils are also the raw material for most plastics. The plastics industry has developed explosively over the past half century. By 1971 an average apartment contained about 1 ton of plastic. A modern Scandinavian apartment contains 2 to 3 tons of plastics (Plastic Industries of Denmark), in everything from the sheathing on electric cables to floor finishes and window frames (Table 9.2). The building industry uses 25% of all plastics produced.

Distillates from fossil oils are all hydrocarbons. These are chemical compounds containing only carbon and hydrogen.

The explanation of how fossil oils have been formed has changed over the centuries. They were once considered to come from the corpses of those who died during the great flood described in the Bible; theories later claimed that it came from rain from outer space. Today, it is common knowledge that crude oil, natural gas and coal are all primarily formed from animal and plant remains that have accumulated in shallow stretches of sea in prehistoric times, and were later exposed to extreme geological pressure and temperature. A main origin of the North Sea oil is shrimp faeces.

Six thousand years ago the Babylonians jointed their clay block houses with bitumen from asphalt lakes. Wider use of fossil oils did not really start until the nineteenth century, when the industry began with the exploitation of reserves on the American continent. The main use of oil products was as a fuel, and later for waterproofing. It was not until the twentieth century that oils were first used for the commercial production of plastics. Today's consumption is nearly 20 kg of plastic a year for every person on the planet (Stevens, 2002), and an increase by 80% is estimated between 2000 and 2030 (Phylipsen etal., 2002).

Resources of fossil oils are very limited. Existing reserves are estimated to last another 30 to 50 years at present rates of extraction.

|Table 9.1 Basic materials from fossil oils

Material

Areas of use

DC

Bitumen

Roofing felts; wind barriers; damp-proofing; mastics

< Û.

Plastics

Roofing; flooring; interior cladding; window and door frames and furniture; flashing and gutters; thermal insulation; damp-proofing; vapour barriers and vapour retarders; mastics and sealing strips; wallpaper; paints and varnishes; adhesives

Organic solvents

Additives in paints, varnishes, adhesives and mastics; production of plastics

Other chemicals

Production of plastics; additives in concrete, plastics and plant materials, paints, adhesives, varnishes, biocides

Gas reserves are slightly greater than reserves of crude oil, while coal reserves could last more than 100 years.

After being pumped to the surface, oil and gas are transported to refineries for distillation into different fractions. Some of these are then further processed to produce paints, plastics and other materials. Extraction, refining and production of the final material all cause industrial pollution. Every time an oil tanker unloads, many tons of the lightest hydrocarbons escape into the atmosphere. Fishing grounds and coastal areas can face ecological ruin for decades in the event of an oil blow-out or when oil tankers are wrecked. The catastrophic potential of oil can thus be used as a political weapon -as in the Gulf War when the oil wells of Kuwait were set on fire. The oil industry is similar in character to the nuclear industry in its geopolitical and strategic influence.

The processing of oil to plastics and other materials requires a great deal of energy (Table 9.3) the energy intensity of the plastics industries is similar to that of the metal industries. Large amounts of the greenhouse gas carbon dioxide and acidic sulphur dioxide are released. Many of the additional pollutants from the production process are highly toxic, including hydrocarbons and heavy metals

Table 9.2 The use of plastic in a typical Scandinavian dwelling

Area of application

kg

Percentage

Flooring

800

30

Adhesives, mastics

700

26

Pipework

425

16

Paints and fillers

275

10

Wallpaper, membranes

200

8

Thermal insulation

100

4

Electrical installation

100

4

Sealing strips, skirtings, etc.

50

2

Total

2650

100

Table 9.3 Embodied energy1 in selected products based on fossil oils

Product

Manufacture (MJ/kg)

Combustion value (MJ/kg)

Embodied energy (MJ/kg)

Bitumen-products

DC

- Bitumen

10

40

50

< Û.

Plastics

- Polyethylene

67

43

110

- Polypropylene

72

43

115

- Polystyren EPS

77

48

125

- Polystyren XPS

82

48

130

- Polyurethane

105

30

135

- Polyvinyl chloride

65

20

85

Organic solvents

- Ethylene glycol

24

44

68

- Methanol

47

30

77

- Xylene

26

47

74

Other chemicals

- Acrylic acid

32

34

66

- Formaldehyde

23

13

36

- Vinyl chloride

26

30

56

1 Note: The embodied energy is defined as the sum of the energy used to manufacture a product and the combustion value of the product. It is assumed that raw material inputs which are not left in the material are used as energy source or as raw material for other products.

1 Note: The embodied energy is defined as the sum of the energy used to manufacture a product and the combustion value of the product. It is assumed that raw material inputs which are not left in the material are used as energy source or as raw material for other products.

required for processing. This does not affect the natural environment alone. Cancer and chemically induced nerve disorders are more frequent amongst workers in these industries than in the general population. Children born with deformities are more common in areas near plastics factories than elsewhere.

When used in building, oil-based products can release volatile organic compounds either as direct emissions or through chemical reactions with other materials, such as concrete. Organic solvents (for example, in paints) will eventually evaporate completely and are greenhouse gases. These and other emissions from plastics can also irritate the mucous membranes and produce traditional symptoms of a bad indoor climate such as irritation in the eyes, nose and throat, unusual tiredness, headache, giddiness, sickness and increased frequency of respiratory illnesses. Other more serious emissions can cause allergies, cancers or foetal malformation. There has also been a marked increase in deaths due to smoke inhalation from building fires during the last few decades, and one reason for this is the increased use of plastics in buildings (Curwell et al., 2002). Smoke from plastics has also been shown to caused lung damage and hypersensibility amongst firemen (Bakke, 2000).

As waste, the sheer volume of plastics can pose a problem since many plastics break down very slowly in the natural environment. A rapid increase in concentrations of plastics in the oceans has been recorded (Browne et al., 2007). These will quite often include toxic compounds and should best be taken care of at special disposal facilities. When released in nature the potential effect through the food chain can be dramatic.

Asphalt can be recycled quite effectively and mixed into new asphalt. Recycling is also possible for some plastics. All plastics, however, contain additives and impurities that lead to a lower quality plastic after recycling (down-cycling). Even if the energy consumption in recycling is less than in its original manufacture from virgin raw materials, the high energy costs of transport still have to be taken into account, as the plastics industry is highly centralized.

Energy recovery has become a very common option for waste products like solvents, oil-based chemicals and plastics. These have a high energy content, but (with a few exceptions) must be burned in furnaces with special facilities for cleaning the emissions. Even so, there is a chance that very toxic pollutants such as dioxins and heavy metals will be released. Regardless of the combustion technology, carbon dioxide is released in similar quantities to combustion of fossil fuels - since these products have much the same chemical composition.

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