Recently the incinerator proposed for Cornwall has had its planning permission revoked, so we can look forward to another round of legal battles and more wasted money, wasted unless you are in the legal profession of course!

Does anyone have in-depth knowledge of the process of slow and/or fast pyrolysis? It seems to be a good technique of dealing with most of the organic rubbish which finds its way into landfill or the incinerator.

Before the flood of comments about reduce, reuse and recycle come in, I would like to say that I agree that is the best way but, in the real world, we need a better way to dispose of the rubbish in the near future.

In pyrolysis, the organic rubbish is ground small and dried to remove most of the water content, then is heated in an oxygen deprived atmosphere. This produces gas, oil and a solid char. The proportion of each can be adjusted by changing the conditions and is also dependent on the raw material. The gas produced can be used to heat the process plant in a closed loop and any excess modified separately into liquid fuel. The oil can be used as is or refined into diesel fuel. As the exhaust gases are recirculated into the plant there are no or very few emissions from the plant. The char is, according to the trial results, a very effective slow release fertiliser and soil improver.

I don't think pyrolysis plants are available off the shelf yet and the technique is not fully sorted, but it seems to offer such possibilities that I am surprised (or suspicious) that there is not more publicity about it.

if it all sounds too good to be true, then maybe we could dig a little deeper and see if this is one which is actually as good as it sounds

Actually, it's been going fo a while...

http://www.idea.gov.uk/idk/aio/1108696

"The first commercial pyrolysis, gasification and high temperature oxidation company in the world. The company was founded in 1992 and as early as October 2001 was granted the Integrated Pollution Prevention and Control authorisation (IPPC). The annual processing volumes are 8 thousand tons of waste mainly from medical origin."

http://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process

Anyway no one shd be burning our precious stock of unoxidised hydrocarbon feedstock - shd be stockpiled (aka landfilled) until such time as
a) Australian automatic mining/waste sorting technology evolves further
b) cost and unreliable supply of virgin petrochemical feedstock makes it economic
to 'quarry' the stockpiles.

BW The original suggestion was a method of disposing of domestic and trade waste, not to provide an alternative source of power, although there may be some energy not used by the process plus the by-products.

FT I will try to regard the landfill site as a future goldmine, and it is a valid point, if the holes in the ground were available. Unfortunately, Cornwall is almost out of landfill sites and has been taking some from Devon, so I guess Devon must be in a similar pickle.

That source of reliable info, Wikipedia, has an article on the subject of pyrolysis - have a look at
http://en.wikipedia.org/wiki/Biomass_gasification

Oxford Catalysts Group have made a small-scale ( I think it is a 60cm cube!) micro-channel reactor for conversion of oilfield flare gas to liquid fuel, which is worth a look, as the technique should also work on clean bio-gas

EDIT - wasted my time making it look nice, having seen how it loaded here !!

This might be a useful data set I found when checking out a high temperature induction heated pyrolysis plant by Pyromex - if there is a better place to stick it, I'm sure someone will suggest one

Note the values for paraffin (heating oil) and old car tyres especially

Calorific Values of
Secondary Energy Materials kcal/kg (approx.) kJ/kg (approx.) kW/kg (approx.)
Bamboo 3'800 15'900 4.4
Brown coal 4'500 18'900 5.2
Cacao shrub 3'300 13'800 3.8
Cardboard 3'800 16'900 4.4
Cardboard corrugated 3'910 16'400 4.5
Car tires 8'300 34'800 9.6
China grass 4'030 16'900 4.6
Citrus peels 4’500 18'900 5.2
Coconut shell 3'800 15'900 4.4
Coffee bean shells 6'000 25'100 6.8
Compost 4'200 17'600 4.8
Cork 6'300 26'400 7.3
Corn 4'400 18'400 5.1
Cotton seeds 3'300 13'800 3.8
Hay 3'200 13'400 3.7
Hospital waste 6'780 28'500 7.8
Household waste presorted 4'500 18'900 5.2
Leather 4'020 16'800 4.6
Manure (dried) 3'760 15'900 4.4
Neoprene 7'100 29'700 8.2
Newspaper 3’910 16'400 4.5
Nylon 7'570 31'700 8.8
Oil sludge 8'800 36'800 10.2
Paper 4'400 18'400 5.1
Paper adhesive coated 4'200 17'600 4.8
Paper coated 6'390 26'800 7.4
Paper sludge 3'910 16'400 4.5
Tar paper 6'390 26'800 7.4
Paraffin 10'340 43'300 12.1
Plywood 4'500 18'900 5.2
Polyethan foam 9'770 40'900 11.3
Polyethylene 10'990 46'100 12.7
Polypropylene 11'030 46'200 12.8
Polystyrol carbon reinforced 10'840 45'400 12.6
Polystyrol EPS 9'800 41'100 11.3
Rice pods 2'900 12'100 3.3
Rubber 5'600 23'400 6.5
Sewage sludge (dried) 3'300 13'800 3.8
Sunflower residue 4'200 17'600 4.8
Straw 4'000 17'200 4.6
Tar acid 5'600 23'400 6.5
Tar and refinery residues 9'200 38'500 10.7
Textiles 4'000 16'700 4.6
Tobacco powder 3'000 12'600 3.4
Treated wood 4'500 18'900 5.2
Untreated wood 4'200 17'600 4.8