Plastic to fuel projects are beginning to gain attraction in the energy industry. The rising awareness of the prolific environmental damage due to single-use plastics and people’s insufficient recycling habits which lead researchers to turn to alternative disposal methods for our mounting plastic output.
Estimates show that production of plastic is increasing by 3.8 % every year until 2030 & less than 5% of the plastic manufactured each year is recycled. The un-recycled plastic ends up in oceans which discrupts marine ecosystems
which researchers predict would take a minimum of 450 years to biodegrade, if ever.
One way to remove plastic from the earth is to follow a potential approach of " Plastic to Energy" which unlocks the chemical energy stored in plastic waste and use it to create fuel.
How plastic to energy works
Plastic is made from refined crude oil. Its price and production are dictated by the petrochemical industry and the availability of oil. As oil is a finite natural resource, the most sustainable option would be to reduce crude-oil consumption by recycling the plastic and recovering as much of the raw material as possible.
There are two types of recycling:
Mechanical recycling involves sorting, cleaning and shredding plastic to make pellets, which can then be fashioned into other products.
This approach works very well if plastic wastes are sorted according to their chemical composition.
Chemical recycling, in contrast, turns the plastic into an energy carrier or feedstock for fuels.
There are two different processes by which this can be done:
Gasification involves heating the waste plastic with air or steam, to produce a valuable industrial gas mixtures called “synthesis gas”, or syngas.
This can then be used to produce diesel and petrol, or burned directly in boilers to generate electricity.
Pyrolysis : Plastic waste is heated in the absence of oxygen, which produces mixture of oil similar to crude oil. This can be further refined into transportation fuels.
Gasification and pyrolysis are completely different processes to simply incinerating the plastic.
The main goal of incineration is simply to destroy the waste, thus keeping it out of landfill. The heat released from incineration might be used to produce steam to drive a turbine and generate electricity, but this is only a by-product.
Gasification and pyrolysis can produce electricity or fuels, and provide more flexible ways of storing energy than incineration. They also have much lower emissions of sulfur and nitrogen oxides than incineration.
Currently, incineration plants are viewed as an alternative energy supply source and a modern way of driving a circular economy, particularly in Japan, South Korea and China, where land is valuable and energy resources are scarce.
Story Source : TheConversation