Waste plastic is clearly not biomass, but this material, which is typically landfilled, serves many of the same purposes as refined biomass—it reduces demand on and extends current supplies of petroleum, increases alternative energy options, and puts waste streams to good, productive use.
I bring up this topic here to explain why Biorefining Magazine will cover this issue from time to time. And it’s not so far off our mission topic, really; MSW streams, considered “biomass,” often contain high percentages of plastics.
I don’t think the idea is in conflict with encouraging people to recycle plastic either. Recyclable plastic has codes, one through six, but there is a lot of plastic that isn’t coded and therefore cannot be easily recycled, and even coded plastic has to be clean, mixed with like plastics of the same color and more to be effectively recycled. In addition, there is a growing movement to make more of the plastic we use daily from biobased polymers. We cover this issue almost weekly, and certainly in every print magazine. But one aspect of bioplastics that is less talked about is how recyclable are the biomass-based plastics? What, if any, are the technical issues to be aware of?
This was one of several topics I discussed in April on The Biorefining Blog, my weekly blog on biorefiningmagazine.com. Some interesting comments were received, including one from Joseph Witherspoon, who posted feedback, saying, “I am glad to see this issue discussed. Recycling and reusing has its place and purpose, however, even the recycled and reused plastic ultimately ends up in the landfill unless it is consumed. Converting [it] to fuel is a great way to consume and eliminate the plastic that would otherwise accumulate in a landfill. Additionally, converting plastic to fuel recovers and utilizes the available energy in the material. Watch for developing technologies that will convert plastics, any plastic, including chlorides, into high-quality fuels.”
CEO of Houston-based Enhanced Biofuels, Roman Wolff, a regular on both of my weekly blogs (The Biorefining Blog and F.A.M.E. Forum on biodieselmagazine.com), has decades of experience in the refining sector. In response to my post, he said, “Recyclable plastics tend to make better fuel than nonrecyclable plastic. Plastics with chlorine atoms (PVC and other derivatives of vinyl chloride monomer) should not be burned—think dioxins. Even good technologies will end up making hydrochloric acid and require clean-up steps. I am not saying don’t do it, just do it right. Bioplastics will likely be a lot less recyclable than today’s plastics (if done right), because they will be biodegradable—plastic bags will break down instead of killing dolphins or creating a trash island.”
Author: Ron Kotrba
Editor, Biorefining Magazine