In a pilot test, Dow said it recovered 96 percent of available energy from 578 pounds of incinerated plastic at one of its waste treatment facilities in Midland, Mich. The energy recovered was equivalent to 11.1 million BTUs of natural gas and was used as fuel for Dow’s incinerator.
The test used linear low-density polyethylene (LLDPE) scrap film generated in one of Dow’s extrusion laboratories. It is the same type of film commonly used for packaging food and consumer products.
The trial will help Dow as it seeks to develop several energy efficiency projects recently chosen to receive funding through its Energy Intensity Improvement Fund. The $100 million investment fund targets Dow projects designed to help reduce energy usage and greenhouse gas emissions.
Dow has a long-term goal of recycling 100 percent of used packaging.
“The purpose of the test was to collect data showing that used plastic can provide a valuable source of energy and ultimately help reduce our need for natural gas or other fossil fuels,” said Jeff Wooster, plastics sustainability leader for Dow’s North American Plastics business. “The study results demonstrate that almost all of the available energy stored in used plastic can be captured and reused as opposed to being buried in a landfill.”
Recovering energy from used plastic frees up more gas and oil for the manufacture of raw plastics, Dow noted. When the plastic is recycled, much of the energy content of the original feedstock can be recovered, getting greater utility out of every molecule.
While most thermoplastics can be reprocessed, there currently are limited end-of-life options for certain types of used plastic packaging, such as some flexible films and containers made from a combination of materials, Dow said.
“Energy recovery and chemical transformation do not replace the traditional means of recycling plastics – they extend and complement it,” Wooster said.
“The U.S. lags behind many other countries that capture trapped energy from recovered materials,” he added. “Recovering embedded energy in recycled plastic is a ‘best-in-class’ approach used in Europe and other regions. Our next step is to help find a way to scale up this more sustainable practice in the United States.”