Energy Analysis in the PVC Shoe-Sole Production Process: From Raw Material to Final Product

One of the main processes of shoe-sole production is injection molding, in which the desired shape is achieved by injecting a heated thermoplastic polymer in a highly plastic state under high pressure into the mold cavity. The study shows the energy analysis and share of electricity costs in the process of injection into the mold cavity to achieve the desired shape and describe the production process of PVC. Although fairly accurate energy-consumption comparison in the injection-molding process is almost unachievable since it depends on the type of machine, feedstock and molded product, it is still crucial for optimizing energy efficiency. The analysis showed that the basic process requirements of shoe-sole injection molding requires electrical energy in the amount of 5.76 kWh per pair of produced soles, while an increase in energy efficiency and environmental pollution reduction can be achieved by the return of process condensate, with a return share of Y = 80%. The price of electricity per pair of manufactured shoe soles is calculated, and given the fluctuations regarding fossil fuel market, the heat recovery potential leading to fossil-fuel savings in PVC production is analyzed.