[Gasification] BIOCOAL ENERGY CONSUMPTION

Tombreed tombreed2010 at gmail.com
Wed Jul 18 10:13:43 CDT 2012


All

I don't know where Thomas Koch got the 50%, but 10-20% is much more reasonable based on DRY WOOD as a starting point.

Tom Reed n




Thomas B Reed 


On Jul 17, 2012, at 8:51 PM, Peter & Kerry <realpowersystems at gmail.com> wrote:

> On 18/07/2012 5:00 AM, gasification-request at lists.bioenergylists.org wrote:
>> From: Thomas Koch<tk at tke.dk>
>> 
>> Subject: Re: [Gasification] BIOCOAL - THE WOOD FUEL OF THE FUTURE
>> 
>> But it will cost 50 % of the heating value of the wood
> 
> Thomas, I am unsure where this number comes from could you give more detail?
> 
> In straight energy recovery terms it really depends on a number of factors including level of torrefaction as determined by temperature and residence times. We would expect 90% retained energy for the product we are aiming for, though the overall energy efficiency of the process will be lower as a % of the original wood delivered to the plant is used to run the process. The trade off is a "specified" fuel with much higher utility, far better transport economy (not carting energy robbing water), problem free storage and handling with existing coal equipment and uniform very low emission combustion performance vs raw wood fuel. When the first commercial pilot is complete then we will do a energy balance measurement (to compare with the theoretical calculation).
> 
> Although in our circumstance this more for academic interest and as a benchmark to judge future process improvements as in any case the the argument is somewhat moot, current practice (burning waste in Beehive burners) recovers 0% of the embodied waste wood energy for a negative cost to the business. The potential clients they have are not interested in straight wood chip or sawdust as the low energy density and higher handling requirements preclude their "raw" use in their existing coal fired boiler plant at anything like a reasonable co-firing rate (sawdust/chip is usually limited to <5% of fuel feed). New biomass optimised boilers have been ruled out because of their very high cost.
> 
> In one case that we have been asked to consider the fuel spec is so tight in terms of energy density and form that it can only be met by making a blended torrefied wood/charcoal pellet (one approach to achieve this is tweaking the operating parameters of the gasifier in favour of more char production and combining this with the fines from TW retort through a densification plant). Technically this can be done, making it work economically is the bigger challenge.
> 
> Leland also makes a interesting point:
>> There is a company formed to make torrified wood. I am terrified of the prospects as it would be a lot easier to gasify wood at the site of coal use.
> We have tried hard over the years arguing the same case. The reality though is what we call technology inertia, businesses stay with the energy technology they know (straight combustion of solid fuels in the cases we are talking about), they will accept an "improved" solid fuel that does not require much in the way of change to "business as usual" so long as the decision can be easily reversed if it doesn't work out. Interestingly if they are already using a gas fuel, such as LPG then they can much more easily be persuaded to consider an on site gasifier.
> 
> Which raises an interesting future scenario in those countries where large scale fracking is taking place and "cheap" abundant gas supplies are becoming available. Changing over from coal to another fossil fuel, in this case Coal seam or Oil shale gas is a straight forward economic decision by businesses with boilers, particularly where industry price competition is also driving the change. Once this occurs then "step change" to on site gasifiers will become easier in the future a the vastly expanded gas industry gets past its first flush, new energy players fail & or merge to form more monopolistic entities and the gas prices inevitably rise.
> 
> Cheers,
> 
> Peter
> 
> 
> 
> 
> 
> _______________________________________________
> Gasification mailing list
> 
> to Send a Message to the list, use the email address
> Gasification at bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org
> 
> for more Gasifiers,  News and Information see our web site:
> http://gasifiers.bioenergylists.org/




More information about the Gasification mailing list