As noted in my second post, plastic falls into two main categories: thermoset and thermoplastic, the latter forms 92% of plastic and can be recycled, but what about the other 8%? These thermoset plastics (included in the 30.8% of plastics that went to landfill in 2014 in the EU and making up an unknown amount that would've made it into the oceans) are not considered for recycling. So to tackle the issue as a whole, we must look at what can be done about these tougher plastics.
Pyrolysis could be the answer. It involves the thermal breakdown of long molecules in the absence of oxygen and is currently a method of converting waste to fuel and other products including plastic. The video below explains briefly explains how the process works and its benefits:
Plastic pyrolysis can be beneficial for the environment since the conversion to fuel (in this case known as 'syngas') occurs in a closed system and therefore produces less CO2 emissions compared to conventional methods. The latent heat produced during the process can be re-used to further power the system and the gases can also be used to fuel it, reducing the need for external fuel sources. However, the literature and pyrolysis companies fail to address the fact that harmful emissions (albeit less than normal) will be produced upon burning of this syngas. For example, a study by Kalargaris et al. (2017) found that fuel from plastic pyrolysis can have properties similar to diesel but emits considerably more NOx. The majority of the information regarding the advantages and (seemingly non-existent) disadvantages, come from the pyrolysis companies themselves, with very few independent studies available. Because of this, there are many uncertainties around plastic pyrolysis hence its relatively unknown status in the UK (more popular in Japan). Compared with conventional plastic re-cycling and waste reduction, this method seems less beneficial and could detract from the need to reduce consumption. However, with further advances in technology, this process could be a truly viable solution to reduce plastic waste in the future.
Pyrolysis could be the answer. It involves the thermal breakdown of long molecules in the absence of oxygen and is currently a method of converting waste to fuel and other products including plastic. The video below explains briefly explains how the process works and its benefits:
Plastic pyrolysis can be beneficial for the environment since the conversion to fuel (in this case known as 'syngas') occurs in a closed system and therefore produces less CO2 emissions compared to conventional methods. The latent heat produced during the process can be re-used to further power the system and the gases can also be used to fuel it, reducing the need for external fuel sources. However, the literature and pyrolysis companies fail to address the fact that harmful emissions (albeit less than normal) will be produced upon burning of this syngas. For example, a study by Kalargaris et al. (2017) found that fuel from plastic pyrolysis can have properties similar to diesel but emits considerably more NOx. The majority of the information regarding the advantages and (seemingly non-existent) disadvantages, come from the pyrolysis companies themselves, with very few independent studies available. Because of this, there are many uncertainties around plastic pyrolysis hence its relatively unknown status in the UK (more popular in Japan). Compared with conventional plastic re-cycling and waste reduction, this method seems less beneficial and could detract from the need to reduce consumption. However, with further advances in technology, this process could be a truly viable solution to reduce plastic waste in the future.
Comments
Post a Comment