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Old 05-01-2009, 11:39 PM   #11 (permalink)
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Originally Posted by theunchosen View Post
The algae aren't the CO2 devourers. . .the bacteria are.

Its their food. They eat non-stop and they can do it in the dark.
But if they eat the algae, the algae have to be grown in the sunlight - that's where the energy comes from.

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Bacteria use the CO2 and other compounds and run in reverse.
But it takes energy to do that, just like plants grow by capturing energy from sunlight, animals use the energy & exhale CO2.

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Yes of course energy has to come in somewhere. Thats the heat from the coal plant...
No, no, no! Thermodynamics 101. If they're telling you otherwise, they're running a scam.

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Old 05-02-2009, 12:38 AM   #12 (permalink)
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I'll say this one last time. The bacteria primarily eat CO2, not algae not sunlight. They run on Chemosythesis not Photosynthesis. The main consumables for chemo are compounds that contain carbon, sulfur and phosphorous. They only need the algae to provide a little bit of this and a little of that(think vitamins you don't eat more than a few grams, but you eat several pounds of calories.)

If you run the process perfectly in reverse to you, output O2 and sugars yes it requires energy. They don't run it perfectly in reverse. They also only require heat for a warm enfironment, no other energy sources. I'm really not at all certain why I am even arguing this. Bacteria have been doing this for thousands of years with no sunlight, only heat sulfur and CO2. If you think its impossible then take it up with them. first link NASA sends volcano-loving bugs into orbit from google.

I don't know how many coal-fired power plants you've been to but the exhaust gases are hot(not from the steam turbine because thats a closed system, but from the actual coal burner). Yes of course you want to get as many BTUs out before you dump it but there are limits.

I've taken thermo, Kelvin and Plank are happy and the first law is still in place. For me it was ME 3210 and it rather clearly points out that heat engines are never 100% efficient. Stick your hand in front of your muffler, its hot too. And what you suggest is a violation of the Kelvin-Plank statement of the 2nd law of thermodynamics. the law in short says if you are going to do work with heat you will have to reject some heat as non-useable in the process. Thats whats happening out of the exhaust from the burner(not the boiler). Heat that cannot be successfully transferred into the steam or water depending on what kind of plant you are running, is used to preheat incoming air to the burner, which is also used to pre-re-heat liquid in the cycle thats coming out of one of the series of pumps and closed heaters or deaeraters. All said and done its still going to be reasonably hot. Effectively as exactly hot as saturated water(the last regenerative cycle for the exhausts will be at the lowest turbine pressure at saturation temperature and the gasses will be slightly warmer than the fluid approaching the saturation point). Which happens to be the temperature the bacterie exist at in nature.
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Old 05-02-2009, 12:56 PM   #13 (permalink)
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OK, but where are those carbon, sulfur, & phosphorus-containing compounds going to come from? This is just basic conservation of energy: if your bacteria are going to run the endothermic reaction that splits apart CO2, then they have to also be running some exothermic reaction(s) to get the energy. Your chemosynthetic bacteria are just using different reactions on compounds found in rocks.

As for the thermodynamics, you seem to have missed an important point, which is that you can't extract energy from something that's at a constant temperature. You need a temperature difference. Thermophile bacteria (the sort that live in hot springs & ocean vents) aren't extracting energy from the heat of their evironment, that's just where they live comfortably.
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Old 05-02-2009, 02:10 PM   #14 (permalink)
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Originally Posted by jamesqf View Post
OK, but where are those carbon, sulfur, & phosphorus-containing compounds going to come from? This is just basic conservation of energy: if your bacteria are going to run the endothermic reaction that splits apart CO2, then they have to also be running some exothermic reaction(s) to get the energy. Your chemosynthetic bacteria are just using different reactions on compounds found in rocks.

As for the thermodynamics, you seem to have missed an important point, which is that you can't extract energy from something that's at a constant temperature. You need a temperature difference. Thermophile bacteria (the sort that live in hot springs & ocean vents) aren't extracting energy from the heat of their evironment, that's just where they live comfortably.
Are you suggesting that I can't stick a turbine into an extremely hot flow and get work? I understand there has to be a differential. . .but the differential doesn't cause the work. That is how a turbine works.

The turbine converts the enthalpy of the inlet state to work and the enthalpy at the exit state. That said if I yank the turbine out of the system the temperature is the same on both sides.

As to the sulfur compounds. . .that happens when you burn coal. We are talking about using bacteria to clean and convert exhaust gasses from a coal-fired burner(not the boiler) into less co2, more o2 and some fuel as well as alot of bacteria growth. All of the compounds except phosphur are available in coal exhausts.

The bacteria are then using the heat to aide with their own enzymes in doing active conversion of chemicals into new chemicals. The result is the temperature downstream of the bacteria is marginally cooler(depending on how many bacteria) and there is alot less CO2.

For the sake of argument just to make you happy we'll say that it requires sunlight and we are using algae only. Its already been done. The only problem still remaining to use algae as a filter is it would have to be replaced too often because it can't take the fatigue loading. If you don't believe me string together a phrase that has something to do with CO2 algae and power plant and hit I'm feeling lucky. More than likely you'll get a relevant page.

The aforementioned process is easier because it can run 24/7 instead of 12/7. Like the Algae though survivability is poor and not competitive at this point. However, the results are getting much more promising with more firms developing cyclic resistant algae as well as the bacteria achieving longer lifetimes.
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Old 05-02-2009, 06:05 PM   #15 (permalink)
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Originally Posted by theunchosen View Post
Are you suggesting that I can't stick a turbine into an extremely hot flow and get work?
The critical word there is "flow". Why do you have a flow? Pressure differential, no? And in most turbines, you've created that differential by heating something (by burning coal in the case of a powerplant) thus raising the temperature & pressure. But if you're using exhaust heat from the powerplant to make a nice warm environment for your bacteria, there's not going to be any PT differential.

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As to the sulfur compounds. . .that happens when you burn coal.
So what exactly happens to the sulfur in the coal? You don't suppose it could be oxidized to SO2 in another exothermic reaction?
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Old 05-02-2009, 06:21 PM   #16 (permalink)
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Thats my point, james. The exhaust gasses aren't going to be at ATP. They are going to be higher. Since its an exhaust system its exaspirating. There will be flow as long as its running. So as long as those bacteria can continually have a warm place to asisst in their active conversion they will function. They will absorb heat in the reaction and it will get colder, thats why its important that its a flow.

You don't suppose that oceanic indigenous sulfur does that as well? It does. It does it alot more than at ATP because oceanic pressures are incredible at that depth. . .in the deep spots where most of the vents and bacteria are its 10-16 KPSI compared to 14.7 PSI in the stack. The icnreased pressure increases the odds of really bizarre reactions taking place ambiently so NOx, SOx and just about any other combination that we encounter occuring anywhere else occurs there.

If the exhaust gases are warmer than the surrounding air outside the stack there will be flow and therefore there will be a differential. If you had a good enough turbine you could make it work on those exhaust gases.

We don't have any of those. Its not an issue of too much temperature in the stack its an issue of too much debris. The particulates stick to the walls and cause buildup. On a turbine thats fatal.

Also it really doesn't matter in the least what we do with these exhaust gases because they are useless to the plant at this point. So if you are getting at the reduced flow coming out of the bac tank thats really not that important. As long as there is not tremendous back pressure it will not affect the burner.

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