Plastics processing, energy conservation

Progress and Prospects for Energy Conservation in Plastics Processing... 

Heat. Thermal energy has proved to be easiest to conserve in plastics processing. Conservation has taken many forms produc-... 

H. Croezen and H. Sas, Evaluation of the Texaco-Gasification Process for Treatment of Mixed Plastic Household Waste, Centre for Energy Conservation and Environmental Technology, Delft, The Netherlands, 1997. 

In the United States, liquid petroleum gases (LPG), natural gas liquids (NGL), and natural gas are used to produce plastics. In 2010, the US plastic production accounted for only about 2.1% of the total petroleum and 1.7% of the natural gas consumed. The electricity used was estimated at a further 1% of the consumption. Then estimating conservatively, only about 5.4% of petroleum resources were devoted to manufacturing plastics (US Energy Information Administration, 2013). The operational or process energy may add another approximately 3 % to this, bringing the total fossil fuel investment in plastics to about 8.6%. 

Canadian Industry Program for Energy Conservation [CIPEC]. Guide to Energy Efficiency Opportunities in the Canadian Plastics Processing Industry. Ottawa Her Majesty the Queen in Right of Canada 2007. 

Plastics waste processing, in particular, has direct links with the conservation of energy and natural resources, and the development of technology is the best solution to deal with plastics waste material. Plastics processing is used to recycle waste, which is driven by the potential depletion of raw materials and socio-economic factors. However, the direct reprocessing of plastics waste is limited due to contamination or the mixture of different kinds of materials. 

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. 

Table 5 shows data of the energy balance for different recycling processes. Here the energy conservation results from the polyolefine fraction under consideration of the life cycle including the first-production of the plastics material.[10]... 

In retrospect, it should not be surprising that a time independent theory modeled after elasticity theory does not apply to a plastic flow process. Elastic deformation is conservative with the work done on the material stored as elastic strain energy. Plastic deformation is non-conservative with the work done on the material dissipated as heat, or converted into internal defects... 

There is no sharp dividing line between plastic mortars and sealants, but the former are usually in situ-polymerized, highly-filled, rigid composites while the latter are usually in sltu-polymerized, flexible polymers. Since plastic mortars do not require expensive molds, the phenolic and urea plastic motars were the pioneer plastics. The Interest in these readily fabricated, labor-intensive, plastics decreased as automated molding processes were developed. However, because of their excellent properties and the need to conserve energy, there is an renewed interest in these materials. 

Mathematical models are used for these purposes in the plastic/ chemical, petrochemical, and other industries. Computer-aided design (CAD), computer-aided manufacturing (CAM) are use in product designs and product manufacturing operations. The essential elements of any model of a physical process are threefold the geometry, the relevant laws of physical conservation (momentum, mass, and energy), and the specific constitutive relations (see the Software section in Chapter 9). 

The plastics indnstry mnst actively develop and promote strategies to extract the maximum possible useful service life from all plastics. Increasing the service life conserves raw materials as well as energy. A waste material shonld be viewed as an asset (a possible raw material) rather than a disposal problem, with the focns on search for processes and markets that can make a useful product out of it. Recycling shonld be practiced whenever the resource recovery can be achieved at substantial overall savings in fossil fuel energy with minimum pollution. 

---