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Algae Gasifiers

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Algae Gasifiers

Postby guayacan » Mon Dec 29, 2008 10:27 pm

I saw a video regarding this on YouTube and was wondering if anyone had any information regarding to this subject.
Whilst I knew that the cake could be put through the gasifier, I was surprised by the use of a catalyst in the gasifier to create diesel and gasoline.
Has anyone got any idea what catalyst would be used here. If this is true, then one of the biggest obstacles with algae will be solved, that being commercially viable extraction and processing. I think the name of the chap was David James, but I welcome any other articles, or whatever, regarding this subject.
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Re: Algae Gasifiers

Postby cacofonix » Tue Dec 30, 2008 8:43 am

Hi,

I won't say I know a lot about the gasification process, but this is what I am aware of: Any biomass (even stuff like trash), can be put through what is called a thermo-chemical reaction to derive a range of liquid fuels, including diesel and gasoline. There are two stages in this process.

Stage 1 is the gasification stage where the biomass is gasified or pyrolysed (the difference between the two is that the latter is done at relatively lower temp and pressure). The result of gasification/pyrolysis is what is called synthetic gas (Syngas).

The next step involves running this syngas either through a chemical process aided by catalysts (called catalytic conversion) or through biochemical routes (for instance, fermentation using micro-organisms) to produce a range of fuels.

Now the good news is almost all the stages described above are well understood and have been used for some industry or the other for decades. The bad news is that the capital costs of these gasification/pyrolysis set-up are huge.

And you are absolutely correct when you said that this is a more straight-forward route for algae - it at least avoids the costs of extraction, and more important, we need not be bothered too much about the oil content of algae; my guess is, most any algae, including macro-algae should be OK!

This indeed is an interesting route and I am happy to report that a number of companies have started exploring this route rather seriously - not all of them use algae biomass, but that should only be a matter of time
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Re: Algae Gasifiers - catalysts

Postby Taknittothestreets » Mon Feb 02, 2009 1:00 am

From a layman's point of view:

Gasification seems like the way to go with algae and any other organic material because you don't have to build a plant to expell or squish out the oil, you just have burn it out using very little oxygen (i.e., smoldering coals). Since you are not really burnuing up the "fuel", but rather gasifying it, you now have an opportunity to collect the fuel as a gas or convert it back to oil - think of the tarry pitch you get on the bottom of your camping cookware when you use it over an open fire. but how do you take the gas and convert it to oil? You run it through or over a catalyst! But as mentioned here: "Has anyone got any idea what catalyst would be used here. If this is true, then one of the biggest obstacles with algae will be solved, that being commercially viable extraction and processing"

Catalysts appear to be a closely guarded secret in any business as you will find the term used loosely, but never clearly defined. From my research, it appears that the catalyst for this application is some kind of metal. Several metals seem to be acceptable, from iron ferrous to Zinc, But most recently I have come across some indication that a mixture of cobalt and magnesium oxide will work.

From what I can tell (chemistry for dummies - remember, I am a layman), the catalyst attracts the hydrogen molecules and affixes them into place so that the other molecules (i.e., carbon and oxygen to name a few) in the gaseous mixture can more readily align and attach to the hydrogen molecules (otherwise its a kaotic affair and the chance for alignment is lessened greatly, hence the catalyst) which after becomming satured, fall off as precipitate, ready to be collected as oil. ??? I may not have it 100% correct, but I definitely have enough to experiment with and that will be the fun part!

Good Luck and remember to Take it to the Streets! 8-)
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Re: Algae Gasifiers

Postby cacofonix » Mon Feb 09, 2009 9:11 pm

Taknittothestreets,

First off, nice user name - albeit a long one :-)

I agree with you - gasification is the way to go. Just imagine - you dry the algae, then squeeze the oil and then transesterify it...and I am not sure how much of these can be continuous processes...sounds terribly complicated...as against just dumping the algae into the gasifier and then FT-ing the syngas and voila you get fuel...

I know it is not as easy as I make it sound, but I am sure the whole gasifier thingie is one seamless continuous process, or close to that...only gasification can achieve the scales of fuel production to satisfy the world's mammoth use of transportation fuel - about 12 MT per day and rising
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Re: Algae Gasifiers

Postby DR Johansen » Mon Feb 09, 2009 9:54 pm

Personally (and I am NOT a professional about this) I think the optimum process will prove out to be the supercritical CO2 process. Pump wet algae into the SC CO2 reaction chamber, seperate the algae-oil from the CO2+oil, extract them from the chamber, lower the pressure on the SC CO2 until it is a gas and the oil falls out. Then repressurize the CO2 and pump it thru the chamber again. This can easily be made a contiuous flow process with very little pumping losses if you use a pressure recuperator. No need to dry the algae, and it MAY survive the processs to make more little algae and more oil in days to come!
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Re: Algae Gasifiers

Postby cacofonix » Mon Feb 09, 2009 10:14 pm

DR, I am not sure I agree with you on that...supercritical CO2 might be continuous and might achieve scale, but consider how many bottlenecks are there.

You need to find the right strain of algae and grow it in controlled circumstances, these are much bigger problems than they appear to be - I am sure you are aware of it

On the other hand, consider gasification. It is simplicity itself - take any algae biomass (micro, macro, any strain simply doesn't matter, why it need not even be biomass, anything that has hydrocarbons in it!) dump it in the gasifier and you get fuel.

Frankly, I think we need to just wait until people are able to get gasification capex to more acceptable levels. Then the world biofuels industry might shift to gasification + catalytic synthesis

On a related note, I read about one company (Syntec), which has claimed that they are able to get capex for gasification / FT to be $2.23 per annual gallon and approx production cost per gallon @ US$ 0.78 (including feedstock cost). Now this was in 2006, and if the company's numbers are true, I wonder why the world isn't running to gasification
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Re: Algae Gasifiers

Postby DR Johansen » Tue Feb 10, 2009 1:24 am

One problem I see with the gasification route is that all the nutrients in the algae could be lost to future use. With some of the kinder, gentler methods, the remainder can be used for other things. Also, the minor chemicals found in the nutrients tend to poison the catalysts, IIRC.

If you were talking about corn rubble or switch grass which is almost all cellulose and lignin, then fine, but I just see it as a terrible waste to burn up all those valuable proteins etc.

Livestock of the world unite for algae meal! :D
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Re: Algae Gasifiers

Postby cacofonix » Tue Feb 10, 2009 8:40 am

You have a point DR, I agree...

The problem with gasification might simply be that we are losing lots of inorganic stuff...so if we can choose those feedstocks (not necessarily algae) that are very rich in only carbs and lipids...and very poor in proteins...so we are using the feedstock for what they are really good for
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Re: Algae Gasifiers

Postby guayacan » Mon Feb 16, 2009 3:03 am

Thanks to all that have contributed comments. I am still convinced that gasifying algae is no more cruel than gasifying switchgrass or other. Algae is a purposely grown feedstock, in which it would not have had any existence should it not have been to sacrifice itself in the gasifier. Although I do see large markets for animal feed, chemical industry etc, I think that we need to get green fuels in the market first. The simplicity of the gasifier, to turn algae to diesel etc, is the key. No straight carbon chains, lipid extraction, transesterififcation, biodiesel equipment, waste products etc. Quite simple, algae , dry it, and then use a gasifier (and not ultra high temp either). A gasifier simply cheats time and creates products that normally take thousands of years.

But as for the protein waste etc, they were wasted to create the original crude anyway. It isn't as though they have conscience.
Perhaps in the future we can afford the use of a process to remove the protein before the gasification, but until then, let's remember the biggest obstacle that we are trying to achieve, and that is viable cost green alternative fuel. The secret is in those catalysts, of which I suspect there are two in tandem.
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Re: Algae Gasifiers

Postby cacofonix » Mon Feb 16, 2009 7:32 am

"A gasifier simply cheats time and creates products that normally take thousands of years. "...I think this really is the key point, and I completely agree..

Million of years back, algae were taken in by the earth, subjected to enormous pressure & temp and other environmental extremes and over many thousands of years, they formed oil...gasifier indeed is an attempt in recreating this process by cheating time...the analogy in fact sounds apt. If indeed it can be clearly proven that gasifiers are energy positive (with a reasonable EROEI) for very large scale production, my guess that is the only way the world will move, or rather, should move
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