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Ethanol/electricity from waste?
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MacG



Joined: 24 Nov 2005
Posts: 2866
Location: Scandinavia

PostPosted: Wed Jun 22, 2005 8:39 am    Post subject: Reply with quote

Blue Peter wrote:
Bootstrapper wrote:
To produce liquid fuels like ethanol or biodiesel, we must put more energy into the process than we'll get out in the fuel it produces.


Is this necessarily true?


Peter.


Yes. But you could have some of it for free, kind of, if you put in something which has converted sunlight to biomass. Such as trees.
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Blue Peter



Joined: 24 Nov 2005
Posts: 1841
Location: Milton Keynes

PostPosted: Wed Jun 22, 2005 10:22 am    Post subject: Reply with quote

MacG wrote:
Blue Peter wrote:
Bootstrapper wrote:
To produce liquid fuels like ethanol or biodiesel, we must put more energy into the process than we'll get out in the fuel it produces.


Is this necessarily true?


Peter.


Yes. But you could have some of it for free, kind of, if you put in something which has converted sunlight to biomass. Such as trees.


That's what I was trying to get at. However, from Bootstrapper's reply, he seems to be talking about a "laws of thermodynamics" type necessity - which is obviously true, but not quite so useful in this context. I was wondering if there really was something that said that we couldn't get a positive EROEI for the production of liquid fuels. I don't think that there is; it just depends upon the process and the amount of "free energy" you can get from the sun, wind, etc.


Peter.

P.S. And to be pedantic, in Bootstrapper's initial quote, he did say energy that WE put in Laughing
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Bootstrapper



Joined: 24 Nov 2005
Posts: 91
Location: Canberra, Australia

PostPosted: Fri Jun 24, 2005 8:08 pm    Post subject: Reply with quote

Blue Peter wrote:
MacG wrote:
Blue Peter wrote:
Bootstrapper wrote:
To produce liquid fuels like ethanol or biodiesel, we must put more energy into the process than we'll get out in the fuel it produces.


Is this necessarily true?


Peter.


Yes. But you could have some of it for free, kind of, if you put in something which has converted sunlight to biomass. Such as trees.


That's what I was trying to get at. However, from Bootstrapper's reply, he seems to be talking about a "laws of thermodynamics" type necessity - which is obviously true, but not quite so useful in this context. I was wondering if there really was something that said that we couldn't get a positive EROEI for the production of liquid fuels. I don't think that there is; it just depends upon the process and the amount of "free energy" you can get from the sun, wind, etc.


Peter.

P.S. And to be pedantic, in Bootstrapper's initial quote, he did say energy that WE put in Laughing


Laughing I was taking the 'big picture' and you're right, it probably isn't that useful in this context. Embarassed Thanks for bringing me back to Earth.

I made the point that the heat for the initial reaction could be supplied by burning some of the feedstock. What bugs me is that it isn't shown in the diagram or specified in the text. Since the feedstock is considered waste and would be discarded as having no value, then the energy that is extracted from it could be considered 'free', in an economic sense.

In that case, the plant could be self-sustaining, as the value of the outputs (fuel, gas, heat etc.) would be greater than the costs of the inputs (the feedstock waste). You'd be extracting energy from a source that is free, except for the cost of extraction. The cost of extraction is having to burn some of your feedstock. The same process applies in the oil industry. A refinery burns crude oil to heat the fractional distillation towers in which the various petroleum products are distilled.

Also consider, the capital needed to undertake construction of a plant on this scale wouldn't be available after the economic crash that peak oil could induce. This is why I prefer to consider 'cottage-industry' type solutions. Did I mention I'm a fan of E.F. Schumacher? Wink
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DamianB
Site Admin


Joined: 24 Nov 2005
Posts: 554
Location: Dorset

PostPosted: Wed Sep 14, 2005 10:50 am    Post subject: Reply with quote

Waste is a resource that offers opportunities for the recovery of useful materials and energy.

With this in mind Compact Power has developed a new advanced thermal conversion technology for a wide range of wastes using pyrolysis, gasification and high temperature oxidation.

This is an economic new energy and materials recovery technology for the processing of wastes. Units of plant are designed to process waste streams with widely differing calorific values. They have a nominal throughput capacity in the range of 8,000 to 32,000 tonnes per annum producing heat, electricity and other materials. Where greater capacity is required two or more systems can be combined.

This state of the art technology ensures that the strictest emissions standards are met.

After nearly ten years of research and development including the building and operation of a full scale pilot plant a commercial plant has been built in Avonmouth, Bristol, UK.

This plant will meet all objectives for a sustainable waste management strategy. It is the key for local solutions with recycling and composting and energy recovery from residual waste. With its potential for "thermal recycling" a zero waste strategy is achievable.

Compact Power provides a flexible process that fits well with other waste separation and recovery processes. It is economic at smaller scales to optimise community based integrated waste management, and provides an ideal solution for the processing of difficult and industrial wastes.

http://www.compactpower.co.uk/
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