Any quantity of oxygen can be present and it need to verified the security of some part in this mixt processus : pyrolysis and combustion.

Just burn all the waste plastics is easiest and safest. Use the exothermal energy!   

The main issue is whether there is a significant amount of oxygen in the make up. As soon as you have oxygen, then the products will contain oxygen. In the volatiles this adds up to organic acids which are a challenge. On straight plastics and the like, it is a wonderful method of recycling as the quality of the liquid fuel can be upgraded to some extent by relatively cheap means.

Dear all;

I would say producing rather recovering raw material or even materials. This process is already done for decades, and I wonder if from the economical point of view if it is benificial. The main advantage of recycling is to enhance and participate into the environmental issue.

Since it is possible to do this process under an inert atmosphere; I don't see any importance to stressing on the presence of oxygen.

At the Algerian Institute of Petroleum I have assisted two master projects where polyolefins have been pyrolyzed to different molecular weights waxes, and the second one is the pyrolysis of polyethylene terephtalate (PET) to its diol and diacid reactants. Regards

Isolation of single materials (as opposed to mixtures) is very difficult and uneconomical, due to the great number produced by pyrolysis. We have concluded that organic materials from a pyrolysis process may only be used as fuels.

I have worked in pyrolysis for almost 50 years and have probably the only technical papers out there on true Heat and Material balances.  Bottom line - with today's fuel prices dealing with any solid fuel is uneconomical. 

My field is fluidized bed reactors and systems.  I agree that the ultimate solution is to recycle the molecules from plastic waste.  During the 1990's when I was working for Dorr-Oliver I headed up an engineering study to develop a fluidized bed process to pyrolyze plastic waste to generate feedstock at the BP oil refinery in Grangemouth Scotland.  The biggest roadblock is the removal of halides such as Fl and Cl from the plastics since these would render the feedstock useless.  The process appeared to be technically feasible but the project was cancelled after our initial study before we could perform test work.  This work was financed by a consortium of European companies involved in oil and plastic production.  I believe the process is feasible but test work would be required.

A note on Rejeev Mehta's response:  Pyrolysis of PVC in the presence of wood produces CH3Cl, see my Argonne US Patent 5,662,052.

We have established a small pilot scale pyrolysis reactor (20L) at our research center and have been working on pyrolysis of different plastic types, waste tires and other feedstocks using different catalysts including natural zeolites. We have published few good articles and book chapter and building our understanding in this technology as a mean of producing fuel and other value-added products.

Furthermore, we know that there are some industrial pyrolysis plants working in different parts of the world.

However, I personally see many challenges with pyrolysis technology before it can be considered as both economical and environmentally friendly technology for treatment of various wastes. The major challenges, of course not all, in my consideration are as following;

1) Energy intensive process

2) Pyrolysis oil is normally quite crude and needs a lot of energy and cost to clean it before can be safely used.

3) Harmful gases produced during pyrolysis process

Any comments welcome.

Few of our recently published articles on pyrolysis for interest

https://www.researchgate.net/publication/306092137_The_Energy_and_Value-Added_Products_from_Pyrolysis_of_Waste_Plastics?ev=prf_pub

https://www.researchgate.net/publication/308893079_Influence_of_temperature_and_reaction_time_on_the_conversion_of_polystyrene_waste_to_pyrolysis_liquid_oil?ev=prf_pub

https://www.researchgate.net/publication/308983786_Effect_of_plastic_waste_types_on_pyrolysis_liquid_oil?ev=prf_pub

https://www.researchgate.net/publication/311912315_Effect_of_zeolite_catalysts_on_pyrolysis_liquid_oil?ev=prf_pub

Chapter The Energy and Value-Added Products from Pyrolysis of Waste Plastics

Article Influence of temperature and reaction time on the conversion...

Article Effect of plastic waste types on pyrolysis liquid oil

Article Effect of zeolite catalysts on pyrolysis liquid oil

Good morning!

The process of pyrolysis, in my humble opinion, comes under the mask of reverse logistics (recycling). Let's mention the tyres, for instance: the process withdraws the polution from the soil and throws it in the air. By the way, there is a new very effective way of reclycling tyres and residues of rubber, which none of the 11 patents existing wolrd wide were able to solve up until now. 

Have a nice day,  Regina

Dear Regina,

you mention some patents and especially a new effective way of recycling tyres and residues of rubber. Do you have any additional information for me?

With best regards

Michael

Dear Michael, 

My answer is inbox, thank you!

Kind regards,

Regina