Talk:Thermal depolymerization
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Yield efficiency
The energy efficiency is not 85%. That would be the yield efficiency. Energy efficiency from a source that is costing nothing, or actually reducing the cost of disposal, is nearly infinite. If you compare the ratio of energy produced to energy consumed you will see 560% (85 BTU for 15 BTU consumed) which might be considered the efficiency for comparison with Ethanol or BioDiesel produced from agricultural processes. These are in the 320% range when you consider the energy used to produce the raw material.
Quoting a process as 85% efficient actually means that you lost energy or consumed 15% more than you produced.
- Quite right, I've updated the article accordingly. Thanks! If you like, you can also edit articles with errors like this yourself; just click "edit this page" and away you go. Be bold. :) Bryan 23:58, 16 Feb 2004 (UTC)
Popularity
It would be interesting to discuss (or link to a discussion) as to why this process is not more widespread. What's the catch?
- My guess would be that it's a combination of newness and the fact that it isn't actually economically competitive with fossil fuels as a fuel source yet - it's still cheaper to get it out of the ground than it is to make it by thermal depolymerization. The current pilot plant is intended more as a means of waste disposal than it is a fuel source, though the fuel it produces helps to offset the cost of the waste disposal. Perhaps once oil prices have climbed more it will start looking more attractive as a substitute for that. Bryan 23:54, 23 Apr 2004 (UTC)
- Or once the technology is developed enough to reduce the cost of production? Nik42 04:41, 14 Apr 2005 (UTC)
Two Small Suggestions
I have two small suggestions for this article, but as I am new to Wikipedia, I'm reluctant to make the edits directly.
Regarding the efficiency, I think the number is still off by a little bit. In reading the 85% efficiency discussion, I understood that it took 15 units of energy to produce 100 units of energy. Fifteen of those 100 units are then fed back into the process to produce another 100 units, leaving 85 units from the original "batch." In other words, 85 units of energy are produced from nothing (which is useless for calculating efficiency) or 100 units from the seed 15 units. Thus, the efficiency using the second method of calculation should be 100/15 = 660%. As a comparison, it would be interesting to know similar numbers for taking crude out of the ground and processing it. I have read (I don't know where) that it was 100 or even 1000 to 1 at one time, but that we are much closer to 1:1 these days.
Regarding the efficiency of producing biodiesel and ethanol, it was not clear which method of calculation was used to come up with 320% efficiency. I assume that it is the second method (I don't think the first method could yield greater than 100% efficiency), but it would be nice if this were stated explicitly.
- Consider the fuel needed to start the process as a trivial construction expense, then 15% expense after that. (SEWilco 03:46, 1 Apr 2005 (UTC))
One small nitpick...
...the article says that thermal depolymerization is "not a new technology". This is a bit misleading, since you might think that people have been doing it for hundreds of years. It'd be like saying "nuclear fusion is not a new technology... the sun has been doing it for millions of years", when the implication of a "technology" is that humans do it, not that nature does it.
Otherwise, I like the article a lot: well written. The technology seems promising too (I hope).
Feedstocks and Output
I just did some research and added some of the specific feedstocks/output since there's been some controversy as to whether or not turkey's are the only economically viable feedstock.
Hope it helps.
I added two paragraphs to the limitations section, lest readers hope this can solve impending energy shortages by itself.
- Your paragraphs was drawing upon too many irrelevant details, such as energy needed to create metal components (perhaps such should be in a separate article about environmental footprints of various technologies). I added some info about the amount of some feedstocks, and noticed that if numerous details were listed it would become a section about waste in general and probably should be in the much-in-need-of-improvement Waste article. I know another possible feedstock is sewage but I didn't look up the figures on that (the EPA Waste section avoids that material). Comparison with total oil usage may be relevant, although fuels used in automobiles/trucks/aircraft should be the focus because those are applications which most need the high energy content of hydrocarbon fuels and thus are probably of greatest importance for replacement of "fossil" fuel. (ie, people might be willing to pay extra for hydrocarbon fuel which does not add new carbon to the atmosphere and avoids the disadvantages of tech which does not use hydrocarbon fuels) -- SEWilco 03:35, 23 Jan 2005 (UTC)
- What about tires? What would they produce? I assume a fair amount of sulfuric acid, as well as some high quality oil, but does anyone have figures?--Joel 04:45, 6 Jun 2005 (UTC)
Life cycle analysis seems to contradict existing material
The new anon-supplied life cycle analysis section says "Currenty Thermal depolymerization is a net energy loss." However, the theory and process section says TDP produces 85 units of energy for every 15 units of energy consumed, which is a significant net gain. Am I misreading something here? Bryan 00:03, 1 Apr 2005 (UTC)
- No, I think that 66.30.79.242 is doing the misreading. The blog post (http://myrrander.blogspot.com/2005/02/energy-pipe-dreams-thermal.html) to which .242 added a link in the References section interprets "85% efficiency" to mean that for every 100 units of energy put into running, the process only returns 85 units -- a net energy loss. However, this is not a correct interpretation of the figures; 85% is not the total percentage of energy gotten out of the process, it's the percentage of the energy gotten out of the process which is "profit" -- which is returned after the break-even point.
- I really can't see a benefit to keeping this misinformation in the article; accordingly, I'm removing 66.30.79.242's changes. -- Antaeus Feldspar 01:14, 1 Apr 2005 (UTC)
- I agree with the removal. In addition to this 85% nonsense, the source [1] (http://myrrander.blogspot.com/2005/02/energy-pipe-dreams-thermal.html) deliberately confuses the alleged production cost of oil with its cost to the refiner to come up with a projected cost of $200/gallon of gasoline! Not too surprising for a source which is explicitly left wing. pstudier 01:25, 2005 Apr 1 (UTC)
- Um? I thought it was very surprising for a left-wing source (for so it seemed to be) to say "no, no, this revolutionary new energy technology is all bunkum; the status quo of getting our oil from the Middle East, that's where it's at"... -- Antaeus Feldspar 01:57, 1 Apr 2005 (UTC)
- I believe that there is a component of the left who want to totally shut down technology. An example is the Khmer Rouge. If thermal depolymerization were able to replace Middle East oil, they would lose an excuse to take away our cars. pstudier 02:09, 2005 Apr 1 (UTC)
- To avoid confusion, you might refer to this class of ideologue as "anti-modernist" or "neo-Luddite". For every Theodore Kaczynski, I've heard from ten loony, left-leaning conspiracy theorists who think that right-wing forces have conspired to prevent people from having electric cars. Also, I've gathered that the stereotypical totalitarian socialist imposes industrialization at the barrel of a gun, rather than finding excuses to do away with it.--Joel 06:28, 7 Jun 2005 (UTC)
Oil from anhydrous pyrolysis
Thermal depolymerization uses hydrous pyrolysis. There are several companies that are developing anhydrous pyrolysis to produce oil [2] (http://www.dynamotive.com/biooil/advantagesbenefits.html). Any reason their technology is not mentioned while TDP is?
- Might be because the process isn't called "thermal depolymerization". The page you link to calls it BioOil but I'm guessing that's a trademark rather than a generic term for the product. Is it related to the "thermo chemical conversion" process mentioned in the lead paragraph of this article? Since it's a different process from the one this article describes, starting a new article for it might be the best approach. Bryan 16:37, 16 Apr 2005 (UTC)
- The anhydrous pyrolysis methods should be in an article on that topic. Anhydrous pyrolysis is basically distillation of organic matter. Heat stuff and collect what boils out. There is a "Technology" page on that BioOil site with some details. (SEWilco 18:11, 16 Apr 2005 (UTC))
- Still, it seems to be a way to produce fuel that can be used in diesel engines from organic waste. Seems to be more economically viable than thermal depolymerization. I changed pyrolysis so that the different techniques are mentioned. Ultramarine 13:49, 17 Apr 2005 (UTC)
- I didn't see on the dynamotive.com web site the information that it is "more economically viable". I do see "Prepared feedstock (<10% moisture and 1-2 mm particle size)", so the feedstock has to be dried. Also, their equivalent of natural gas only supplies 75% of the plant's energy needs, so the plant needs an external energy source or has to burn char or oil product. (SEWilco 14:49, 17 Apr 2005 (UTC))
- TDP is proven not economically viable [3] (http://springfield.news-leader.com/business/today/20050413-Oilplantfacesha.html). On the other hand, the BioOil is at least predicted to be profitable [4] (http://www.dynamotive.com/biooil/advantagesbenefits.html) and seems to much closer to expansion [5] (http://www.dynamotive.com/investors/faq.html) than TDP which seems to be abandoning most of its prior expansion plans.
- Regarding EROI, even if this is negative, it is still a way to produce a liquid fuel useable in today's engines. Ultramarine 15:14, 17 Apr 2005 (UTC)
- That seems like a somewhat biased view of TDP's current status. Changing World Technologies thinks they can be profitable in Europe, where they can get better tax breaks and where it's illegal to feed animal waste to other animals; they aren't abandoning expansion plans, just moving them to other regions. Meanwhile you're only linking to Dynamotive's own website to show predictions of profitability, and it kind of goes without saying that a company is going to try to portray a technology they're developing as being profitable. In any event, though, that still doesn't change the apparent fact that BioOil is not thermal depolymerization and so doesn't belong in this article. Why not make an article specifically for it? Bryan 17:24, 17 Apr 2005 (UTC)
- I'm sure Bryan meant to suggest to create an article about the general process, not the company. There are several similar processes, so don't make too specific an article unless there really is a lot of information about this one process. (SEWilco 18:13, 17 Apr 2005 (UTC))
Supercritical fluid?
Is this a supercritical fluid technique? I've been trying to see if the pressures in the system ever go over 200 bar (20 MPa) because this whole process sounds like a supercritical fluid technique. Supercritical water can breakdown almost anything, it can even tear the radioactive contaminents off of tools. 40 bar (4MPa) as stated in the article is an extremely low pressure. Does anyone know if the pressures within the system (most likely when the temperature jumps to 500C) ever goes over 200 bar? Email me because I would like to mention this in my thesis. Water's critical point is 218.3bar and 374C. --Lebite 15:43, 16 May 2005 (UTC) lebite@yahoo.com
- I don't know, but I doubt it. 200 bar is awkward to work with, and they're only trying to break up organic molecules a little rather than breaking everything down to elemental forms. (SEWilco 03:00, 17 May 2005 (UTC))
- No, they are trying to break down everything, even old circuit boards. And I did manage to find a report on the process. It is a supercritical process. I have to finish my thesis this week so I don't have time to add these details into the article, but I hope to add them in the future. I found a technical paper about the process used with pig manure. After flashing, it goes to subcritical and supercritical state. At this point, it should be able to break anything down to its elemental form. Supercritical water methods are the future of dyeing, cleaning, waste management, reaction media, refining, mining, and a bunch of other things. --130.230.30.231 10:33, 23 May 2005 (UTC) lebite
- That makes it rather interesting that they're getting any oil out of it rather than only methane. (SEWilco 17:50, 23 May 2005 (UTC))
rm apparent speculation
- Critics have charged that this violates the first law of thermodynamics which implies that no system can be greater than 100% efficient. Thermal depolymerization, however, only converts the energy that is already contained in the waste product into a more usable form of energy. The entire system, which includes the sun, is probably less than 1% efficient. In the case of turkey offal, sunlgiht is converted into starches in corn, which is in turn converted into fats and protiens in turkey which is in turn converted into light crude oil in this tdp process. As a system tdp is very inefficient, and it would seem to make more sense to just put up solar panels instead except for the fact that these waste products would be created anyways. Since these waste products are going to be created, tdp improves the overall system efficiency by recovering some of the energy that still resides in the waste matereals.
Is there any source for this material? Since there's no source cited for figures/guesses like "probably less than 1% efficient" or any indication of whose judgement it is that "As a system tdp is very inefficient", I've reverted it but placed it here to see if anything can sourced and salvaged. -- Antaeus Feldspar 23:05, 18 May 2005 (UTC)
- My recollection it that photosynthesis is ~2% efficient at turning sunlight into chemical energy. Going from plants to turkey to hydrocarbon fuels seems like it could easily lose another 50% of that. The point that the turkey guts--or whatever--exist, and have to be disposed of in some cost-effective way is a good one. At a profit for preference, or failing that at the least net cost.
- —wwoods 00:55, 19 May 2005 (UTC)