Energy content of plastics

The energy content of plastics is comparable to that of ordinary combustibles such as diesel oil (Figure 3.12). It has been shown that the addition of between 7.5 and 15 wt% of plastics waste to municipal solid waste improves combustion in the gas phase as well as of the solid residues due to a more stable and intensive combustion zone [58]. It also reduces waste volume by two thirds [59]. The mineralised combustion residues need to be disposed of as hazardous waste. 

The Energy Content of Plastics Articles, British Plastics Federation, London, 1986. Company brochure, Solvay et Cie, PVC and The Environment, 1986. 

Anon, The Energy Content of Plastics Articles, Association of Plastics Manufacturers in Europe, Distributed in the United Kingdom by the British Plastics Federation, Publication No.309/1, (April, 1986). 

Recruitment of a species depends on the abundance of the brood. Abundance, in its turn, is influenced by the fertility of the population and by the quality of the reproductive products. Such quality comprises specific features of the genome and the content of plastic (proteins, phospholipids and cholesterol) and energy (triacyl-glycerols, wax esters and glycogen)... 

It can be seen that a significant proportion of the energy content of the waste is recovered by the gasification of the char and that the ultimate residue is decreased in comparison with the quantity of bottom ash produced compared with direct incineration. Solid plastic waste represents a significant stream for conversion back to energy [89]. 

The greenhouse gas carbon dioxide is emitted by the chemical breakdown of certain plastics, not using the energy content of the material which is not utilized. For this reason, such plastics are only used if their degradation process involves an additional utility factor. Examples of this are polyesteramide sacks for collecting plant material the sacks rot together with the plant material (manufacturer Bayer)... 

It is pertinent from these structiues that nitro arrd azide groups make plasticizers to have energetic properties. In addition to these plasticizers, also neutral plasticizers such as DOP and other plasticizers are used in these applications. The plasticizers or their combinations are selected to achieve the reqirired effect. Inert plasticizers usrrally lower the energy content of polymers used in explosives (e.g., nitrocellulose). 

Treatment and recovery of plastics mixtures is more difficult. For example, about 3%-5% of household rubbish consists of plastics mixtures. Such mixtures can indeed be cleaned, reduced, and directly processed but the end products obtained in this way, however, have very poor mechanical properties because of the incompatibilities of polymers contained in the mixture. The subsequent sorting of plastic mixtures by hand is expensive and not reliable. Even the separate collection of old plastics is uneconomic, and indeed, even with unpaid volunteers. On the other hand, utilization of the thermal content of plastics as an energy source during rubbish combustion is economic, since the amount of oil required for complete combustion is reduced. 

For every 1 million vehicles the total savings achievable by replacing steel bonnets with plastic amounts to 23(X)0 tonnes of crude oil, considerably more than the energy content of the plastic bonnets. In Western Europe in the mid-1990s there are 130 million passenger cars with an average life le of 160000 km. 

Polymers use their main feedstock—the crude oil—more efficiently than the direct incineration of it which is true today for more than 82% of fuel consumption. Plastics—which need ca. 6% of the total fuel demand in Germany—can be considered as the first recycling loop of crude oil since aU the energy content of the fuel is preserved and can stiU be used after disposal of plastic products. 

Quaternary recycling is the useful retrieval of the energy content of scrap plastic by its use as a fuel to produce products such as steam, electricity, and so forth. ... 

Plastic material CO from incineration Avoided utility CO, (MT Energy content of... 

The recycling of plastics waste provides an ecologically acceptable way of reutilising the energy content of the waste. The plastics processing operation is damaging to the environment and inefficient if the polymer composition of the waste is unknown. It is necessary to conserve and dispose of plastics waste as there is no alternative solution, hence it should be considered as a resource disposal techniques depend on the type of waste and location. 

Energy Content of Reinforced Plastics Materials, International Reinforced Plastics Industry (IRPI), London, Nov. 1981. 

As would be expected from the chemical structure, the energy content of hydrocarbon-based polymers is similar to that of heating oil and is over twice that of paper-based waste. Hence plastic waste is a potentially valuable form of fuel. Incineration of plastics, as part of municipal waste, is especially suitable for small items such as thin films and small containers such as yoghurt cartons that are impractical to collect and sort for other forms of recycling. As with other forms of energy generation the heat from the combustion process is used to drive a steam turbine to generate electricity. 

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