5Kw home power methane system - help needed

[ashtweth]

Thanks Jim

Not trying to be negative, just realistic/practical. I got REAL excited, back in the 60's-70's when I first read about this. I imagined running my house off the methane gas from my families waste; sewer and garbage scraps, maybe some rabbit droppings? Feeding it to a genset, and telling the UTE co. to stick it, while running all sorts of electrical appliances, etc. off it.
Never actually DID it, but I did research it, and FROM WHAT I UNDERSTAND, your NOT going to run the 'typical' house; that is power it totally or primarily off of methane.We just use too much power, and our 'waste' doesn't produce enough gas.
Now, if you eschew the 'standard' lifestyle, which is very energy gobbling, and use methane as 1 of several different alternative sources, and don't figure its going to supply ALL your needs, then yeah, its definetly do-able.
In fact, its the lowest tech of the 'alternative' energy sources out there.

It could be used in conjuction with jetsys "Plastic into Diesel", for instance.Because even tho the system he is working on produces a fuel like diesel, and a fuel like gasoline, it ALSO produces a gaseous fuel, like methane/butane. No reason why that gas couldn't be stored with the methane from the digester. And, he has to heat the plastic up, in order to do the conversion process, but I'm not sure the gaseous fuel produced is enough to operate the system, by itself.Methane could 'fill' the gap, perhaps?

And, something I've been thinking of for that project, to store it more practically; I see used oxygen concentrators on craigslist all the time, going fairly cheap; $100-$300 ea.) Saw the inside of one, once; its a series of graduated size compressors; so the output from the first comprseeor goes into a slightly smaller compressor, and so on, in order to compress to considerable amounts. And, it has a zonolyte (?) filter, to remove the nitrogen.
Not sure you would need that, for this purpose. I don't think these oxygen concentrators use a tremendous amount of energy, so it might be practical to use. Also wondered about a wind turbine, running a compressor.

Like the idea of used 'propane' refrigerator, as they run on a little pilot light, which is on, 24/7. If your not going to compress the gas, you want to use it as it is being produced, because storing it takes a lot of space, and DOES have certain dangers. Wonder if such a refirgerator could be modified, to be an A/C unit? Should work, in which case you could use the gas to refrigerate food, and perhaps cool your house? Just didn't want people having flights of fantasy, like I did, and imagining they could get all their energy needs, from the poop and garbage they produce, is all.
Actually, could also look at a produce (plant) that would give you the most gas, with the least amount of work/land, and grow the raw material. And, animals are still a great bet; rabbits would be good, as the waste would be very easy to collect.Unfortunately, according to Rick, if you try to sell them, as pets or as meat, the FDA will shut you down Fuggin go'ment. They would also probably find you in violation of something, if they found out you were producing more than a farts worth of methane.Jim

Thanks Jim, the urban environment would be a challenge especially with those regulations etc, i still like the idea of a back up power unit with that drum idea, however check out how small they can be done for emergency heat.

Homemade Biogas Generator - YouTube

[rickoff]

wonder what the MATH, is on that with what waste and how much gas it needs to at least HALF your power bill,

you could at least half or lower power bill CHEAP with a simple kitchen scrap model, or use it to power a genset charge your batteries,
irregardless its SAFE and CHEAP back up power(or saving)

Hi Ash,

Not sure about that setup, but here is a video which shows a 650 watt generator will run for about 3 minutes on around 100 liters of biogas. It all depends upon what one's electric power needs are, but just for example my September usage was 300 kilowatt hours. Now let us assume that if a 650 watt generator runs 3 minutes on 100 liters biogas then a 1,000 watt generator would consume 154 liters of biogas in the same amount of time, since (1,000/650) x 100 = 154. To run for one hour, and produce 1 kilowatt hour of electric power, would thus require 20 times that amount of biogas, or 3,080 liters. Therefore, if I wanted to produce 300 kilowatt hours and eliminate my monthly electric utility bill using biogas, it would require 300 times that amount, or 3,080 x 300 = 924,000 liters, which equates to a daily biogas volume requirement of 30,800 liters. Since there are roughly 30 24-hour days, or 720 hours, available each month, my required daily average run time to produce 300 kilowatt hours would be 10 hours (300/720) x 24 = 10 hours. There is no question that many a household could meet its electric supply needs using this example of a 1kw generator running 10 hours a day if power usage is planned wisely. The question becomes whether or not it is feasible to produce and maintain an output of 30,800 liters of biogas during a 10 hour period, and of course that depends upon the size and efficiency of operation of the digester unit being employed. Remember that 3,080 liters per hour equates to 51.3 liters per minute, or nearly 1 liter per second, and that is a considerable amount of biogas. It is said that 1 pound of cow manure at 28C degrees can potentially produce about 1 cubic meter of biogas. Whether or not that amount of gas could be produced in just one day remains to be seen, and of course would depend upon the efficiency of the digester. If such an amount could be produced in one day, it would therefore require 2.4 pounds of manure to produce 1 cubic meter (1,000 liters) of biogas within a 10 hour period, or about 74 pounds to produce 30,800 liters during the same amount of time. Now supposing that it might possibly take 5 days to produce that amount of gas from 74 pounds of manure, it stands to reason that it would require about 888 pounds of manure to produce the desired amount of gas (30,800 liters) in 10 hours. In the 5 day example, that 888 pounds of manure would equate to around 111 gallons of slurry, so this should help give you some idea of the digester size that might be required if 5 days were the case. Remember that if the 5 day example were to hold true then you would actually be producing biogas at the rate of 73,920 liters per 24 hour day (3,080 x 24), and would require a digester capacity not only to hold the 111 gallons of slurry, but to also have adequate headroom for the volume of gas being produced. If you are continuously using about the same amount that is being produced then you won't require much headroom, but if you were to run a 1kw generator only 10 hours a day then you would want to utilize as much of the excess volume of production as possible for cooking gas and heating hot water, etc., and you would still want to provide for adequate expansion of any excess gas not being fully utilized. Remember that 3,080 liters of biogas per hour equates to over 50 liters per minute, so the rate of expansion is quite rapid.

As another example, gas engines require about 1/2 a cubic meter of methane per horsepower per hour to maintain idle speed, so if you are thinking about running a 5 horsepower generator engine on biogas, your requirement would be 2.5 cubic meters per hour, or around 2,500 liters (42 liters per minute) to run at idle speed. At high enough rpm to obtain the rated output of the generator head, you are going to consume considerably more biogas.

Incidentally, the YouTube channel which I linked to at the beginning of this post has several excellent videos about biogas production and enhancements, including the use of brickage weights to obtain the desired output pressure, and a solar heating apparatus used to raise the internal temperature of the biogas digester.

[gene gene]

Do not use 2 stroke engine

Hi all,
Thanks Rick, for doing the math.
IMHO the 2 stroke engine used in the video posted by Rick, will not last long. In a 2 stroke all bottom end (crank shaft & rod bearings) are lubricated by the oil & gas mix which is drawn into the crankcase before entering the combustion chamber. The lubrication must be introduced with the gas.
Fortunately most larger gen sets have 4 stroke engines and this is not a problem.
Gene

[Shadesz]

Hi all,
Thanks Rick, for doing the math.
IMHO the 2 stroke engine used in the video posted by Rick, will not last long. In a 2 stroke all bottom end (crank shaft & rod bearings) are lubricated by the oil & gas mix which is drawn into the crankcase before entering the combustion chamber. The lubrication must be introduced with the gas.
Fortunately most larger gen sets have 4 stroke engines and this is not a problem.
Gene

I wonder if bubbling the gas through a pneumatic lubricator would do the trick? In the end though, 4 stroke is better.

Rick,
To my knowledge it takes up to a full month to fully digest material anaerobically, in optimal conditions....

[theremart]

Nice,

I am glad he got the funding to continue this experiment.

Here are the helpful links I found from my time with Jean pain ( you can see the thread I created for this on this board )


But here are some good links on this issue..


Good compost ->

composting part 1-Paul Taylor - YouTube


PANDSCORP — Maximizing Resources . . . Making Life Better



Hot Water and Methane, plus Compost, from Wood Chips? | Green-Trust.Org

http://mariposagardens.org/Handouts/Composting/Compost_Festival_Displays.pdf

Another Kind of Energy



Heat free (nearly) with a compost furnace « Energymd – Practical Alternative Energy

[dutchdivco]

hurrumph

Yes, thanks Rick, for providing the #'s to support what I was trying to say; it takes a lot of s*it, or whatever, and a big unit to supply all your emergy needs, even if you only use electricity 10hrs. a day.

On the its being used in China, etc. In my research years ago, don't know the source, I saw something which said in a part of the world where this is more common (China, India?) a calculation is made, when hiring an employee, as to whether he lives too far away from the workplace to go home at lunchtime; if so he is a more desirable employee, because he's more likely to,....contribute some raw material to the digester, to the employers benefit.

Does seem to me like evergreen trees produce a lot of needles, and they do it year round.Wonder how good a 'raw' material that is. If you had enough acreage, and an efficient way to collect the tree droppings, might be a start.Especially if you had a couple hundred cows/goats as well.

Wonder what you could do with breeding plants or animals which would produce ideal 'raw' material, and/or selecting for qualities that would make collection as efficient as possible.I should think goats would be better than cows, and rabbits would be ideal; just have a sloping trough onderneath the row of cages, and let gravity do most of the work! Jim

Oh, and I totally agree as to the insanity of feeding cows corn, and then giving them hormones and anti-biotics, to deal with the natural result of feeding them corn, when the evolved to eat grass! What an insanity.

[rickoff]

Hi all,
Thanks Rick, for doing the math.
IMHO the 2 stroke engine used in the video posted by Rick, will not last long. In a 2 stroke all bottom end (crank shaft & rod bearings) are lubricated by the oil & gas mix which is drawn into the crankcase before entering the combustion chamber. The lubrication must be introduced with the gas.
Fortunately most larger gen sets have 4 stroke engines and this is not a problem.
Gene

You are welcome, Gene, and you are also correct in your assumptions concerning the use of 2 stroke engines with methane gas. Methane gas is a very dry gas, and even when used in 4 stroke engines this poses a problem in that the top piston rings have inadequate lubication. Thus, the upper ring or rings will wear prematurely and also cause scuffing of the upper cylinder walls, leading to loss of compression. To get around this problem, an oil injection system must be employed to add a small but adequate amount of lubrication with each intake stroke. The oil used for this purpose should be of a very light grade. One that comes to mind that would be quite suitable is Marvel Mystery Oil, and there are others.

[gene gene]

Hi Rick, I totally agree with you on the importance of top cylinder lubrication. As an after thought I realized that I did not address this in my previous post, and am glad to see that you covered this, for I believe that valves & valve guides, as well as the rings & cylinder, would all suffer without proper lubrication.
Do you think methane gas is dryer than LP gas? I think you can buy generator sets that are set up to run on LP gas.
Regards, Gene

[ashtweth]

Gene , dutch, mart, Shadesz, Rick
you guys remind me why you guys are our future.

@Savvypro sending you some Bio fuel resources in next 2 days,
Thank you ALL and yes i do love you all.
gonna test this , this year and next BTW

Thanks Rick

Ash