EROEI
EROEI
(OP)
Currently from what I've read ethanol is roughly equivalent to burning natural gas to produce charcoal from wood.
If anyone is interested I can post several studies.
If anyone is interested I can post several studies.
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RE: EROEI
i.e. : Lies, damned lies, and statistics.
The indisputable fact is that EtOH is currently net economically negative, and government subsidization of the corn crop first and EtOH production second is the only thing making it financially feasible.
Ostensibly the reason is to foster EtOH production to get money into R&D for the cellulosic process that should be both energy and economically net positive.
However, how often does the government kill a subsidy?
RE: EROEI
I think we all have to understand that Fuel Ethanol is all about having an alternative at any price. Just because gas and oil are better options today, doesn't mean that they will be tomorrow. Oh.. hang on, we could import from Brazil 51c cheaper :)
RE: EROEI
RE: EROEI
jistre - Are you in EtOH operations or design?
RE: EROEI
RE: EROEI
RE: EROEI
And if one were to fire with enthanol, you'd still have to have an alternative start-up fuel to boot up the process.
And speaking of wood chips, I was also involved in a waste wood pelletizing plant (the fuel from which went to help fire a coal-fired central heating system) that came pretty close to making economic sense. The wood raw material was a true pesky waste that had to be disposed of in some manner. The pelletizing plant added enough value to make hauling the fuel to a boiler able to burn it, marginally worthwhile, and actually environmentally green.
RE: EROEI
There doesn't seem to be a lot of information out there for designing the utilities - useful stuff such as load profiles for boilers and chillers. Given that the core technology is usually from mash prep to DDE, it is surprising that the information seems so hard to get.
RE: EROEI
I have to think it's because fermentation and distillation are such well known processes that these companies are terrified to give out any information lest their own special twist on making moonshine leaks out.
RE: EROEI
I recollect we flew a brewmeister over from Europe to help get our fermentation going in the dead of winter.
RE: EROEI
You state: "There doesn't seem to be a lot of information out there for designing the utilities - useful stuff such as load profiles for boilers and chillers"
Uuuummmmmm... mass and energy balances developed from flowsheets.... Chemical Engineering 101..???
You gets yer load then you buys yer boiler....
What am I missing here ??
-MJC
RE: EROEI
The process flow on the fermentation side of these plants can be extremely complicated. As you're dealing with biologicals, until you get to DD&E, you have to be prepared to do anything at any time with the live cultures to keep the bugs going. Heat them, cool them, feed them, stir them, burp them, move them forward in the process, return them to an earlier point in the process, read to them... they are delicate and FINICKY. On top of that, you throw in batch/continuous process parameters and your actual utility load needs in fermentation can end up being very hard to nail down.
Once you get to distillation, then the operation of the plant becomes more of a typical chemical plant running as a relatively unchanging continuous process, but before you get to that point, the flow of material and energy through fermentation can be a nightmare to untangle.
RE: EROEI
If you know the load profile under a range of operating conditions, such as winter start ups and hot summer days, then you can specify an efficient turndown and consider other, more cost effective, strategies to meet the total requirement of the system.
Having only a peak load severely limits the possible solutions.
RE: EROEI
If you are unsure of the peak laod, design a multi-boiler/multi chiller installation with a mind to turn down and unit efficiencies at partial load.
Over time, 95% of the cost of the utility is energy (natural gas or power) not the capital investment of the equipment. Two units, each rated at 75% of the peak can work.
Another option to consider (even at the prelimnary deisgn stage) is to allow space and interconnecting piping for a temporary (rental) boiler and/or chiller.
http://www.nationwideboiler.com
-MJC
RE: EROEI
RE: EROEI
However, a lot of these operators and process design firms are very protective of their designs and won't give out any information regarding their plants. If you've got several in a row coming up, you might be able to optimize the design through the successive plants and perhaps come up with some retrofits for the first designs by the time you reach the end, but as for getting any information about existing plants from other sources, that might be a bit rough to accomplish.
RE: EROEI
>Hmm... I'd be interested if anyone knows of any plants burning fuel ethanol in the boilers of their ethanol plants!:)
and had to post the following piece from the air permit of a Kentucky bourbon distillery:
-----------begin snip-------------
Emissions Unit 08 (09-001) Indirect Heat Exchanger
Description:
Horizontally-opposed-natural gas-fired indirect heat exchanger
Secondary fuel: Distillate oil (#2 and #4 fuel oil)
Tertiary fuel: Off spec alcohol
Maximum continuous rating: 176 MMBtu/hr
Construction commenced: 1972
-----------end snip--------------
It is being done
RE: EROEI
RE: EROEI
However, as of recently, I bet that the economic benefits are disappearing, and the energy balance questions become more important.
RE: EROEI
Perhaps then the economic distortion caused by government intervention can be appreciated.
Not to mention the environmental disaster fuel EtOH from corn is rapidly becoming.
RE: EROEI
The obvious answer is that we have to get our energy sources into a form in which it can be used in it's intended purpose.
Natural gas is a wonderful energy source (while we have it) but it suffers from low volumetric efficiency, and it can't be added to liquid petroleum based fuels to reduce pinking.
Whether we should be driving injected NG cars might be cause for another forum.