RogueRose
International Hazard
Posts: 1585
Registered: 16-6-2014
Member Is Offline
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Pyrolysis of HD/LDPE, PET, PP, PS, & other
So listening to the radio tonight and they are talking about the epidemic of plastic trash, and it certainly is from my viewpoint. I find recycling
to be a very questionable activity when looked at from a net energy savings point of view. From the need to wash/clean the plastic, separate it then
re-process it into a usable source material, I have to question the viability of it as opposed to collecting it all (no wash/clean) & transport
all together to specialized incinerator for only plastics. So this removes a lot of steps and we aren't left with the process of separation,
re-processing and processing a new product, which is often of sub par quality and usually requires virgin material incorporated into it anyway. I've
been told that the overall expense of recycling is more expensive than using virgin material and is only economical due to massive subsidies,
increased fees in trash collection and many other hidden costs consumers don't know about.
So, from what I have looked at, the product of the pyrolysis of these plastics doesn't produce anything too nasty when done at an adequate temp with
appropriate levels of O2. The one plastic that is somewhat problematic is PVC and that seems to be less used in consumer food products and could be
collected separately or the Cl2 could be absorbed in a CaCO3 bed/spray similar to coal plant flue us it for SO2/SO3 absorption. This process could
probably be incorporated into normal incinerators but maybe process plastics separately (on different days/hours).
There are processes of trying to re-process the plastics into a "crude oil" like product by doing the above process under "high" pressure but it seems
very energy intensive and it does leave behind a waste product, similar to how coal leaves ash/cinder, that is very difficult to process and very
unuseful, so it seems to have a fair bit of negatives when compared. The net energy savings/cost still seem higher than using virgin material.
I've just heard this push for recycling so much and never hear about the process of clean incineration, which seems to be a secret to the news media.
It feels like the waste management industry is behind the recycling push and they never look into alternative ideas b/c it would kill the golden
goose. I'm tired of being told I have to recycle more, separate more, and have to buy stuff made of recycled crap when there are very viable
alternatives from what I've read. Anyone else see this as well, as far as the media coverage and general recycling push? It just seems like another
way to control people and another reason fine people for not washing their trash before putting it in the bin. Tired of the shit.
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Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
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I do not expect sensible solutions from government 
My friend, a beurocrat/accountant/non-engineer working for my local council was part of a senior management team tasked with managing collection and
processing of used cooking fat from commercial premises, to produce bio-diesel for council vehicles.
As the council uses oil-fired boilers for heating of hospitals and schools I suggested that would be a cheaper and more efficient route.
There was no box to tick for that option so they went ahead with bio-diesel 
for a while 
CAUTION : Hobby Chemist, not Professional or even Amateur
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