Recycling energy consumption

Plastics have many advantages. Included are the facts that they have the lowest energy consumption in the recycling processes of about 2 MJ/kg (2 to 2.5 MJ/I) and when incinerated the highest recovery energy content exists of about 42 MJ/kg. Some comparisons with other materials are provided. (1) Processing waste paper requires 6.7 MJ/kg and as a general rule about twice as much paper is needed compared to plastics for 

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In the membrane process, the chlorine (at the anode) and the hydrogen (at the cathode) are kept apart by a selective polymer membrane that allows the sodium ions to pass into the cathodic compartment and react with the hydroxyl ions to form caustic soda. The depleted brine is dechlorinated and recycled to the input stage. As noted already, the membrane cell process is the preferred process for new plants. Diaphragm processes may be acceptable, in some circumstances, but only if nonasbestos diaphragms are used. The energy consumption in a membrane cell process is of the order of 2,200 to 2,500 kilowatt-hours per... 

Improved Materials Processing and Recycling Techniques that Reduce Energy Consumption and GHG Production (e.g., reduction of Portland cement use by substitution of industrial waste products such as fly ash, which has several side-benefits). 

Of course, kinetic resolution processes are not optimal. In order to obtain >50% molar yields, racemization and recycling loops are required which often have a negative impact on solvent and/or energy consumption, as well as on waste production. Obviously, better... 

In spite of its limitations, Gas Recycle technology remains a viable option in certain circumstances where its selection may be favored by plant scale or capacity. Other keys to the decision are as mentioned earlier energy consumption, capital investment, separation efficiency and catalyst vitality. 

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