In reply to  Jed Rothwell's message of Fri, 25 May 2018 22:30:58 -0400:
Hi,
[snip]
><mix...@bigpond.com> wrote:
>
>
>> Plastic bags are made primarily of hydrocarbons.
>>
>> 1.      Dissolved in a solvent, they might make a useful diesel fuel.
>> 2.      Bundled and compressed the bags might be burned instead of coal.
>> 3.      Added to a blast furnace, they could replace, or augment coal.
>>
>
>Trash incinerators are used to produce energy in some places. Unfortunately
>they cause a lot of pollution.
>
>The problem with plastic bags is that the total mass is small, and the
>plastic is scattered around. Bringing it all to one place would take a lot
>of energy. Think of how many plastic bags you use in your daily life.
>Grocery shopping bags, Saran wrap, the bags used packaging in new
>computers, plastic sheets at Lowe's used to keep plants from soiling the
>back of your car, and so on. It seems like a lot, but if you were to gather
>a whole month of that plastic, and burn it, it would burn up in no time. It
>would be nothing compared to the coal or natural gas that is burned to
>provide you with electricity. People who cut and burn firewood to heat
>their houses have gigantic mounds of wood, the size of two or three pickup
>trucks. That's just the fuel need for space heating. Wood has low energy
>density, but not that low. 16 MJ/kg versus 24 MJ/kg for coal. See:
>
>http://energyeducation.ca/encyclopedia/Energy_density
>
>People use large sheets of plastic in some industries, where they unpack
>delicate parts, for example. It might make sense to gather up the plastic
>in a factory and burn it or recycle it some other way.
>
>There are recycling bins for plastic grocery bags. 

This is what I was aiming at. Something to do with the collected bags.

>I suspect this is not
>economical but it is better than scattering the bags around the landscape.
>They cause great harm to wildlife.
Regards,


Robin van Spaandonk

local asymmetry = temporary success

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