A hydrothermal (Hydro-PRS) recycling plant is set to be built in Japan.
Mitsubishi Chemical Corporation (MCC), a licensed partner to Mura and KBR, is on target to finish building said hydrothermal plastic recycling facility by 2023. Capable of handling 20,000 tonnes of plastic waste, MCC is set to increase treatment volume in the future.
Hydro-PRS (short for Hydrothermal Plastic Recycling Solution) refers to an advanced recycling solution patented by UK based plastics pioneer Mura Technology and licensed to its global partner KBR that allows for the recycling of hard to recycle, mixed flexible plastic packaging.
The patented process uses super critical steam (water at elevated pressure and temperature) to convert these multi-layer single-use plastics into the oils and chemicals they were originally made from, readying them from renewed use in recycled products.
As such, the process involves the heating of water within a plant reactor’s chambers to extreme temperatures, said water being kept under pressure to prevent evaporation, leading the liquid to become ‘supercritical’, that is, neither liquid, solid nor gaseous. Plastic waste arriving at the individual facility is then mixed into the supercritical water after having been sorted beforehand. The waste then exits the reactors as vapour which is then condensed into 4 liquids and oils-naphtha, distillate gas oil, heavy gas oil and heavy wax residue.
What is exceptionable about the new technology is that the plastics in question can be infinitely recycled-usually, plastic waste degrades after a certain number of recycling bouts.
Often, conventional methods fail to recycle composite, coloured or multi-layer plastics (think confectionary wrappers!), food contaminated plastic or just plastics that have been incorrectly sorted.
In some cases, plastics that can be recycled are not recycled due to economic reasons or missing infrastructure.
The hydrocarbons produced via Hydro-PRS similarly stand out for their capability of being used in identical settings to run of the mill polymers.
The process is also remarkable for being energy efficient, as it utilises the heat of excess gas generated to raise the temperature of the supercritical water-this is worth highlighting, as overt energy expenditure has been considered a major flaw of chemical recycling in this form for long.
Environmental activists also claim that chemical or ‘advanced’ recycling does not represent a solution to the plastic problem as it only serves to convert plastic waste into oil, which, when burned, is prone to generate another slew of greenhouse gas emissions. They are also insistent on the fact that this ‘plastic-to-fuel’ solution, which sees a relative state change of the plastic waste in question, does not solve the virgin plastic problem-relying on this solution may in fact encourage the production of further plastic, as is argued by environmental NGO’s.
Burning these fuels may also prove a human health hazard.
Cleaning the products of chemical recycling is often necessary, as they may contain large quantities of nitrogen, carbon monoxide as well as carbon dioxide, a process which is both difficult and expensive as well as liable to generate further toxic waste streams.
Chemical recycling has so far also been difficult to implement in developing countries struggling to establish a proper waste collection and segregation system partly due to a lack in technological infrastructure -the ways in which the project will take this into account for its Asian expansion plans yet remains to be seen.
In response to these claims, Mura has stated that its inherently scalable recycling method is not intended to replace existing mechanical recycling methods but meant to complement them by providing waste treatment options for plastic waste otherwise destined for landfill, incineration or open dumping in the environment.
According to Dr. Steve Mahon, CEO of Mura Technology, Hydro-PRS technology can help end the plastic crisis as well as create a sustainable future by ‘keeping the environment free from plastic and oil where it belongs-in the ground.’
By 2025, Mura and KBR intend to recycle 1 million tonnes of plastic waste worldwide, with sites to be located in the US, Europe and Asia.