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Methane - Bio Gas


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I am moving to an area of Thailand that has a lot of hog production. I have the chance to gather the manure from at least 5 farms who grow more that 10,000 hogs each year. This can be used to make quite a bit of methane. What are the thoughts of fellow members?? Within 15 KM, I can get the manure from over 10,000 animals. I would like to have some feedback from the local community.

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BillyBob , I watched a documentary on this subject about China. It Huge there. They are providing methane digesters for many many villagers , its part of a national Plan, I suppose the 'Party' says you get one and have to use it. One example was a factory which had its own Cows which it fed with the waste process from production, a food factory of some sort obviously. The cows thrived on it, produced manure which was then used to produce Methane to turn the factorys generators. Brilliant!

I think for it to take off it has to be pushed from the top down. There are a lot of places near me teaching the people about sustainable living etc.. but I've yet to see any methane digesters. So I don't think you'll have a market for your gas anytime soon, but if you could use the gas for your own use, to turn an engine or something its a different story.

My thoughts for what they are worth , gaseous exchange maybe :o

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Allreadywidely utilised where I live. Pig farms and potatoe processing facilities.

Tell us more Soundman. What comes first the potato or the Pig ? Are they actually using the Gas and what for ?

Sorry, wouldn't have a clue what they use the gas for.

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I have researched this for +10 years.

I have accumulated about 100MB of data.

This data has been there for 30+ years.

Would like to give it to you, just don't know how to.

Before going further let me say,

there is nothing more efficient than electricity,

Hydro is the best

followed by diesel,

followed by benzine.

Solar is by far lower on the list.

Wind generation is lower than solar.

Please, the "small pesant" Bio-digester in China fits a specific need,

and it is for a very small application.

That temperate zone can be very cold.

And no bio-disgester works below 30C.

There is a temp range for production.

Further there is no data on its performance.

Most likely it is political BS and "they" own the factory where it's made.

To have a Bio-Digester, there are several issues involved:

1 - build, or buy a bio-digester

Tank and components should be made of non-ferrous stainless steel,

(as the poo is acidic, the gas is acidic)

2 - fill it

How?,

3 - maintenance (daily, extreme and heavy)

wow, this is almost a book

solids within the poo, including straw and fibers

will rise to the top, and will restrict production.

Many have devised "rotating chains" that will

"beat" and remix the the slurry.

4 - extract the c2h4 (methane, also called "natural gas")

5 - scrub the gas

- tricky, as you cannot use this gas in a benzine auto

(and you cannot use this gas in a diesel,

so there goes the pick-up truck and farm tractor market)

- to use in a benzine engine,

you must pump this raw gas thru a fluid bed or column

of a calcium base so to extract the sulfides, else

when these sulfides mix with h20, you get sulfuric acids

(really bad for a Internal combustion engine)

- BUT this gas can be use for cooking, replacing LPG

however, why would you want to: as

1 - c2h4 has far less BTU's that LPG,

it contains <1,000 BTU per cubic foot,

For C2H4 to equal LPG, you need >2,500 psi, (around 245 bar)

reason, it is a small molecule, just under hydrogen

so you must compress it a lot of it to equal the

volume of LPG, which compresses to a liquid at <100 psi.

You cannot compress c2h4 into a liquid.

LPG is heavier and contain far more heat per cubic foot than natural gas.

Propane and Butane are the primary gases in LPG,

LPG contains 2,500 BTU per cubic foot,

It will compress to a liquid at 15C and 100 psi

in which they are roughly 250 times as dense as they are when gases

- LPG (cooking) is heavily subsidized in Thailand by the government

- You gonna sell your gas? Do you hope to compete with "them"?

Be prepared for some gov official to show up with their hand out.

Worse, you better have a work permit.

2 - you need to compress c2h4 to >2,500+ psi,

it will still not be a liquid.

And you cannot compress it to >2,500 psi

because the only (inexpensive) tank you can place it in

is the LPG tanks, and the are tested to 350 psi.

(so much for the cheap china compressor).

*do not forget, without scrubbing the gas

the life of that tank is severely shortened

and becomes a potential bomb within 5 years.

(and what compressor shall you use $$$?).

6 - Expect you will need up to 30 LPG tanks (for a small digester)

7 - The poo in the tank is good for around 3~4 months.

After that what do you do?

The tank requires pumping out. You will need a "sludge pump".

(Large operation have something similar to a "septic tank truck".)

But where do you place this "Bio-Hazard" slurry?

The farmers in "western" areas allow that to be "sprayed" on their fields.

(they love it, and usually pay a modest fee)

Here, do not expect Thai farmers to change their ways.

Further you have no place for your slurry during the wet season,

as when the rice fields are flooded or growing.

The large farms doing this in western countries

used this gas

- 1970's`1990's, in boiler systems

- 1990's> in gas turbines with a heat exchanger.

Either is used for steam power generation and heat.

Remember they are in a far colder temperate zone.

Their systems are huge and built to last 20+ years.

These infrastructure can cost several million euros.

I propose the Chinese "peasant" bio-digester is like everything else there.

That is "pray that it works a year later".

I do not know if your original question was proposed due to:

- looking for alternative forms of energy or

- from a survivalist point of view

I simply need a way to give you 100Mb of hard-core data.

Perhaps someone on the forum can help.

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This is a decent read

www.homepower.com/files/methane.pdf

The below is condensed from many sources (compiled mid 2006)...

Biogas-Methane-Properties-Production-Use

+ Methane Properties

-> Methane (CH4)

-> is very light at .55:1 to air, odorless, colorless, tasteless

-> The flash point of methane is -369 Fahrenheit or -223 Celsius

-> The boiling point of methane is -260 Fahrenheit or -162 Celsius

-> The auto-ignition temperature of methane is 999 Fahrenheit or 537 Celsius

-> Paper scorches and turns brown at about 450 Fahrenheit.

-> Methane has a flammability range of 5% to 15% in air

-> That means that over 15% methane in air will not ignite.

-> Compressed and stored in the tank

segregation of methane, nitrogen and oxygen occurs

-> As methane is drawn off, and nearing tank depletion,

methane percentage to air can approach 5% to 15%, and explosion can occur

-> Methane gas cools on expansion through a nozzle.

-> It will not ignite when it expands out a nozzle, it will require an ignition source.

-> Any spark or energy source will ignite the methane.

-> Liquefaction of methane is high tech. To liquidfy "pure" methane (LNG) requires

-> psi >1110

-> Temp below -160 F (above this temp it will never liquidfy)

-> note, trace gases modify these parameters

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

+ Production, Method type and flow

-> Methane Digester, constant flow, dual stage (2 tank horizontal layout)

(the better system is to have 2 Digester production units)

-> Production Feedstock = pig \ cow excrement

-> how much is required depends on the system and tank size...

-> Daily (or weekly) in a "constant flow" type system or

-> Every 3~4 months in a "static" type system.

+ Production Issues

-> odor, smell during production = controllable

-> maintain temp of digester unit within range of 85` ~ 105` F (95` F is perfect)

-> use waste heat from engines, passive solar (with maybe thermal cistern)

-> must scrub and dry gas at source, before compression pump

-> remove trace hydrogen sulfides (mixed with water = Corrosive Sulfuric Acid)

-> I've seen where

engine temp =+ 195` negates the acid problem (this removes the water)

-> Over-Production of Methane Gas can be a significant issue

-> see the section on storage

-> what to do with over-production?

-> burn it off (far better than releasing into the atmosphere)

-> give it away, (probably can't sell it due to gov regulations)

+ Production By-Products and Issues

-> The Cow/Pig Dung slurry is a nitrogen rich organic fertilizer

-> It has an odor

-> Disposal of the Cow/Pig Dung slurry

-> Sell or give it away in bulk

-> Provide a service to spray it on crops, fields, pastures

(note equipment needed)

-> unknown how long after application does the odor linger

-> May be health issues of using it on gardens, and

-> Will be gov regulations requiring compliance

+ Methane Storage and Issues

-> Commercial Quantity Distribution, Storage and Transport

-> as LNG (not LPG),

compressed to >2,500 psi and cooled to > -165` F with Liquid Nitrogen

-> shipped in racks of cylinders,

made from large heavy gauge steel or composite epoxy-carbon

-> as CNG, Commercial Automobile Fuel

-> as Gas, compressed to >2,500 psi, not cooled

-> stored in cylinders,

made from heavy gauge steel (scuba type) or composite epoxy-carbon

(these are very different than cylinders used for LPG fueled cars

-> Do-It-Yourself Storage, Transport

-> for all uses, engine fuel, cooking, lighting, heating

-> as Gas, compressed to around <300 psi with shop AC compressor(s)

-> stored in common standard propane or LPG cylinders

-> requires many cylinders

(note the implied gas over-production and logistical issues)

-> note, not very practical for cars @ 300 psi

= small qty of methane = limited distance (see below)

+ Methane as Engine Fuel and Issues

+ Biogas Methane Percentages and BTU

-> Internal Combustion Engines require

18 cubic feet of methane per horse-power per hour

-> About 225 cubic feet of methane gas

equals one gallon of gasoline (@ sea level).

(above if for commercial CNG)

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

-> odor, smell during combustion = none

+ Methane as Engine Fuel Issues

-> EFI engines will likely have issues with the computer adjustments (re-chip)

-> No catalytic converter issues from resulting compounds of combustion

-> No exhaust oxygen sensor issues from resulting compounds of combustion

-> Increased engine emissions output = increased o2 and NitOx

-> Corrosion Issue =

trace hydrogen sulfide mixed with water = Corrosive Sulfuric Acid

-> Scrub and dry gas (at source before compression and storage)

-> Using a gas membrane separator or

-> Bubble methane gas through column of

CaCO3 (calcium carbonate, or limestone) slurry

-> i've seen where engine coolant temps @ +195' F avoids the water formation

but is likely still present in the exhaust system

-> Range of engine compression ratio for methane use is 8:1 to 20:1

-> Perfect compression ratio = 15:1

-> For gasoline engines...

-> Compression can be raise slightly with a turbo or blower

-> For diesel engines - usually no problem for idi or di

-> Injecting Methane Gas

-> For gasoline engines, Carbed or TBI

-> below the butterfly valve is preferred

-> drill the base of the carb base or use drilled spacer plate

-> For gasoline engines with Direct Injection

-> after the throttle butterfly valve is preferred

-> For diesel engines, idi or di

-> after the throttle butterfly valve is preferred

-> note this is an amendment to the incoming air or

the diesel needs a spark ignition (a major engine modification)

+ Methane as Cooking Fuel Issues

-> all Thailand cooking burners are set up to use LPG.

They will have a small pill size (orifice).

They will require modification to use biogas...

both in orifice size and the fuel/air mixture ratio.

One cannot switch back 'n forth between the fuels without issues.

To use LPG is a stove setup for biogas is very, very dangerous.

I don't know but suspect that

1 tank of LPG = 15~20 tanks of biogas (pig manure)

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BillyBobThai ..... and therein lies the problem I think - not in the good fortune to be able to collect so much, but in having to process and store it in such a way as to commercialise the project (unless of course you intend to use it all yourself - it will probably take care of all your domestic needs - with all ac units running 24/7!)

howto sums it up well in his notes - the idea is great, the practical issues are another story: I have it at home (from cows) and I can tell you - its real corrosive stuff - it chews up everything (albeit over time) from the storage tank to the pipework it flows through, to the stove fittings, to the generator fuel parts. Maintenance maintanence maintanence............... it was great idea at the time, but i wouldn;t do it again (mind you the cost of diesel last year made me glad I had it)

So is the idea for self use, or are you wanting to commercialise?

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BillyBobThai ..... and therein lies the problem I think - not in the good fortune to be able to collect so much, but in having to process and store it in such a way as to commercialise the project (unless of course you intend to use it all yourself - it will probably take care of all your domestic needs - with all ac units running 24/7!)

howto sums it up well in his notes - the idea is great, the practical issues are another story: I have it at home (from cows) and I can tell you - its real corrosive stuff - it chews up everything (albeit over time) from the storage tank to the pipework it flows through, to the stove fittings, to the generator fuel parts. Maintenance maintanence maintanence............... it was great idea at the time, but i wouldn;t do it again (mind you the cost of diesel last year made me glad I had it)

So is the idea for self use, or are you wanting to commercialise?

BillyBobThai :

I apologize for my posting being so "dry",

I do not have much time for posting. Just tried to get right to the point.

Maizefarmer:

What do you mean when you said...

"(mind you the cost of diesel last year made me glad I had it)"

Are you using biogas in diesel engines?

Surely your cooking stoves are LPG(?),

then again there are your genset(s).

BTW: I have been "under the weather" for awhile,

I am happy to see you back, hope you are mending well,

your wisdom/ practical experience is truly needed by us.

I would request something from you...

previously upon your return, you mentioned your loss of CommLink...

that being a Hughes SatDish.

I want to know a lot more about it, and/or what you are doing now.

Please, I will not hijack this thread, can you please start a new one?

If you have already done this, can you supply the thread link?

Cheers

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BillyBobThai ..... and therein lies the problem I think - not in the good fortune to be able to collect so much, but in having to process and store it in such a way as to commercialise the project (unless of course you intend to use it all yourself - it will probably take care of all your domestic needs - with all ac units running 24/7!)

howto sums it up well in his notes - the idea is great, the practical issues are another story: I have it at home (from cows) and I can tell you - its real corrosive stuff - it chews up everything (albeit over time) from the storage tank to the pipework it flows through, to the stove fittings, to the generator fuel parts. Maintenance maintanence maintanence............... it was great idea at the time, but i wouldn;t do it again (mind you the cost of diesel last year made me glad I had it)

So is the idea for self use, or are you wanting to commercialise?

BillyBobThai :

I apologize for my posting being so "dry",

I do not have much time for posting. Just tried to get right to the point.

Maizefarmer:

What do you mean when you said...

"(mind you the cost of diesel last year made me glad I had it)"

Are you using biogas in diesel engines?

Yes - and fuel costs over 2008 came home to roost (for me at least) - so from that perspective it certainly did pay off. Over all, it has saved money over the years. The question is: is that saving so much because I have/use a 3phase gennie set, and what would it be if i was just running single phase. Answer - I dont know. Domestically, I think its benefit kicks in with the use of air conditioning. But take ac take of the domestic equation, is it worth it - I'm not so sure. Put it this way: if it is, its only because I have loads of manure to use. Otherwise, it wouldn't. So, if your use is domestic, factor in your professional time and the cost of logistics and set up. If it is worth it, I'm pretty certain its only because of the offset against running ac units. Without them (ie just running hot water, the stove, the tele and lights) I'm not sure its worth the effort cost and hassle.

Surely your cooking stoves are LPG(?),

Yes my stove is an LPG stove - purchased because I had no mains line access to consumer AC: DIY biogas is more corrosive than LPG - its in the storage that the corrision has its main effect. Do a ph test on the sludge that comes out of the drain valve used on low pressure biogas tanks!

then again there are your genset(s).

BTW: I have been "under the weather" for awhile,

I am happy to see you back, hope you are mending well,

your wisdom/ practical experience is truly needed by us.

Oh - Thanks - All over long time back - back to normal as can be now - fine.

I would request something from you...

previously upon your return, you mentioned your loss of CommLink...

that being a Hughes SatDish.

I want to know a lot more about it, and/or what you are doing now.

I had to get a new one - it was a song and dance with the insurance co (as to be expected!) - but its sorted now - pm me with any questions you have on the subject.

Please, I will not hijack this thread, can you please start a new one?

If you have already done this, can you supply the thread link?

Cheers

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First of all, thanks for all who spent their time to respond. :D

For a little perspective of where I am comming from, as an old hippy from the mid 60's, I have had an intrest in alternative sources of energy. I have also been reasearching this topic for the last 40 odd years, and have built a couple of digestors just to satisfy my mental masturbation, but have never been in a situation where I had a dependable source of manure. I will be moving upcountry from Pattaya in the next few months and need something to do keep myself sane. I have a farm that raises out 250+/- pigs just 200 meters from the house. About 5 km away is a man who has 350 sows and just raises young pigs. He makes methane to run a small diesel engine, the kind like is on the 2 wheel tractors, to run 12- 4 foot diameter circulation fans. He has no scrubbing of his gas other than a trap to collect and drain the moisture. His digestor is an concrete tank buried with a domed top. He has no storage other than his digestor top. From what I was told, he runs this engine 24/7. The problem I see for him is that he is not utilizing all of his manure.

For me this just going to be a hobby. I am retired and have a bad heart so I personally will not be doing much if any actual work, only supervising. I plan on hiring

one of the locals to work for me. All of the gas will be used to run a diesel engine to run a generator for use at my home, in laws house and store, and grandmothers house. If this project just breaks even, I will be happy.

Maizefarmer, when I get further into this I would really like to pick your brain.

Thanks again for the dose of reality. :o

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I met with a young American guy in C.Mai last summer for an hour intense conversation on this topic. I can't recall his name, but he said he was very busy in China - promoting methane production on village level.

Some recollections:

>>>> fruits, veges, wet/leafy stuff is great for methane production. the more wet mass, the better, so rotten and/or unsold fruit such as jackfruit, squash, pomelo etc might yield as good or better, pound for pound - than manure.

>>>> one of the most efficient uses of methane was for cooking fuel.

>>>> the left-over residue is excellent for plowing in to garden soil (not a toxic by-product, as mentioned earlier). If worried about toxicity, use it for non-food plants.

just a few recollections, BB

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I saw a methane digester at a pig farm in Puerto Rico that was a continuos flow type, not a batch type. This means they load it at one end and truck out the waste at the other. It was used for cooking. The waste was excellent fertilizer. You might want to dry the waste and sell it as fertilizer. I've also seen batch type units in India at a dairy, also used for cooking and the spent slurry used for fertilizer. It is not difficult to scrub the gas for engine use, by bubbling it through a water/cal mix before using.

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  • 3 weeks later...

There are several of these in Cambodia in small villages where there is no electric grid. I saw one in use the last time I was over there. Set up by a local NGO. The gas is used to run a small generator when it is available to charge the resident's batteries.

The digesters are standard polytube plastic designs in a red brick trench about 1 meter wide and 10 meters long. The manure has to be carried and dumped in a pit at one end. Water needs to be mixed with the manure in the right proportions, and the manure is manually stirred and chunks are broken to make a good slurry. The slurry is transferred via gravity fed pipe and a valve into the digester. Duration of the slurry in the digester is about 30 days, so that is used to calculate exactly how much manure and water they can add to a single digester based on the volume.

PVC pipes take the gas from the polytube to a bunch of rubber tubes that they scavanged somewhere and use for gas storage. Scrap iron filings from a machine shop are used as a sacrificial sulfur scrubber and fit into a homemade filter inline with the PVC. When the generator runs, the engine vacuum pulls the gas out and deflates the rubber tubes, and gradually they are reflated by the gasses released by the bacteria from the digesters.

The digester trenches are covered by a roof to keep out the elements. Not sure how long that polytube will last. I'd hate to be the guy who has to change it. They are double bagged, and apparently the plan is to change it out when either the inner or the outer bag breaks. It'll be down for several weeks during that time. The worst part from my understanding is starting the thing up again. There is a period for a few days where the mixture is highly explosive if you don't fill the thing with CO2 or N2 first, so that requires some oversight.

Otherwise, the villagers seemed capable of running it themselves. It had been in continuous operation for about 3 months when I saw it. These were also continuous flow digesters. And I was told you do end up with a very good liquid fertilizer at the end, but I didn't really stick around to see first hand how well the whole thing worked. To be honest, the whole thing looked like something right out of Journey to Forever, and I suspect somebody's research project.

From what I did see, transporting and mixing that manure was a big, messy problem. You'd be better off locating the digesters near the pig farm, and just building a pipe to a central processing facility for the gas. Seems alot more efficient. Let us know if you actually do something with this plan. I'd love to come take a look at what you made.

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My wife refused to buy commercial fertilizer this year. She bought small tankers of bio digester effluent and had it pumped into her rice paddies. It seemed to work just fine. She was happier to pay him than the fertilizer companies. I was a little surprised that there was very little odor.

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  • 3 weeks later...

Hi-

All those who are interested in this biogas production issue may want to have a look over at this site based over in India

ww.arti-india.org

They have a lot of experience building and developing these inexpensive, practical and simple systems and are even utilized in urban settings. Manure is not required and they have succeeded with using only regular household kitchen scraps etc.

The bi product of gas production is certainly not a bio hazard as was suggested and as mentioned in the other posts here is actually a valuable fertilizer. Sump pumps are not required to remove this material.

Check it out and I wish you the best of luck exploring this interesting subject of biogas.

cheers,

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I like many posters on this topic in various threads, have been studying the subject of Bio-gas for some years. I have decided to delay the construction of a biodigester to process the effluent from my pig farm. Recently there has been a lot of research done on the CN Ratios of various feedstocks which indicate low levels in pig manure hence low methane production. A limited and unreliable gas supply would be of little benefit to me and I am yet to resolve a method of adding more vegetable matter or other feedstock to increase gas production without aggravating potential hard scum formation.

I consider the digester as an important part of my total integrated farm planning but not one that is essential. To be honest I find it hard to justify the expense of building and maintaining the digester and gas handling equipment against the cheap price of grid electricity here.

Currently I am reviewing a composting option which would combine rice straw, manure and crop wastes in a vermicomposting environment. My two issues are odours and the need to condition our farm soil.

Isaanaussie

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Tibetans cooking with methane gas

More than 100,000 Tibetan households are now cooking with gas thanks to an environmentally friendly hole in their backyards.

Pits in which refuse is placed to ferment and produce methane are increasingly being used to meet the energy needs of families across the autonomous region.

Families of five can meet up to 80 percent of their cooking and heating needs courtesy of a pit measuring 0.5 m by 0.5 m and by 0.5 m.

With a potential to save a family about 1,000 yuan ($146) a year, it is estimated more than 100,000 Tibetan households are now making the most of methane gas.

The government began promoting the new fuel in rural areas in 2006 and plans to build 39,468 methane-generating facilities this year.

At the end of 2010, the figure is expected to reach 200,000 across the region.

Puqung, a farmer in Zongxia village in the Tibet autonomous region, uses a methane stove in the kitchen to prepare her family's breakfast.

"We used cow manure for cooking and heating before, but the smell it gave off was so bad I couldn't open my eyes."

The family's stove is now connected to a methane pit in the backyard.

Since the gas came online, the Puqung's kitchen has been much cleaner and much easier on the nose.

"Life is much easier since we don't have to collect livestock manure and firewood any more," Puqung said.

Like her family, almost all households in the large farming village are interested in building methane pits, covered holes in which waste ferments and creates useable gas.

"We are benefiting from the new fuel," Zon'gar, a villager, said.

"It turns waste into treasure."

A cleaner environment and economic profits have made methane pits increasingly popular in rural areas of Tibet.

Jo'nga Cering, an inspector of Tibet's agro-pastoral department, said the regional government has been researching a practicable method of using methane fuel in plateau areas.

"If we build a greenhouse on the methane pit, it ensures the required temperature for fermenting stalks and straws," Jo'nga Cering said. "It proves efficient."

Methane gas not only improves living conditions for farmers and herders it also saves coal and firewood, Jo'nga Cering said.

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Tibetans cooking with methane gas

More than 100,000 Tibetan households are now cooking with gas thanks to an environmentally friendly hole in their backyards.

Pits in which refuse is placed to ferment and produce methane are increasingly being used to meet the energy needs of families across the autonomous region.

Families of five can meet up to 80 percent of their cooking and heating needs courtesy of a pit measuring 0.5 m by 0.5 m and by 0.5 m.

With a potential to save a family about 1,000 yuan ($146) a year, it is estimated more than 100,000 Tibetan households are now making the most of methane gas.

The government began promoting the new fuel in rural areas in 2006 and plans to build 39,468 methane-generating facilities this year.

At the end of 2010, the figure is expected to reach 200,000 across the region.

Puqung, a farmer in Zongxia village in the Tibet autonomous region, uses a methane stove in the kitchen to prepare her family's breakfast.

"We used cow manure for cooking and heating before, but the smell it gave off was so bad I couldn't open my eyes."

The family's stove is now connected to a methane pit in the backyard.

Since the gas came online, the Puqung's kitchen has been much cleaner and much easier on the nose.

"Life is much easier since we don't have to collect livestock manure and firewood any more," Puqung said.

Like her family, almost all households in the large farming village are interested in building methane pits, covered holes in which waste ferments and creates useable gas.

"We are benefiting from the new fuel," Zon'gar, a villager, said.

"It turns waste into treasure."

A cleaner environment and economic profits have made methane pits increasingly popular in rural areas of Tibet.

Jo'nga Cering, an inspector of Tibet's agro-pastoral department, said the regional government has been researching a practicable method of using methane fuel in plateau areas.

"If we build a greenhouse on the methane pit, it ensures the required temperature for fermenting stalks and straws," Jo'nga Cering said. "It proves efficient."

Methane gas not only improves living conditions for farmers and herders it also saves coal and firewood, Jo'nga Cering said.

I get 600mm cube holes dug at a rate of 10 per man per day or about 15 baht. I will bet you right now that these holes will be worth less than that in 3 months time. Same as here, no money, no honey. This article is absolute BS, nothing personal mate

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Tibetans cooking with methane gas

More than 100,000 Tibetan households are now cooking with gas thanks to an environmentally friendly hole in their backyards.

Pits in which refuse is placed to ferment and produce methane are increasingly being used to meet the energy needs of families across the autonomous region.

Families of five can meet up to 80 percent of their cooking and heating needs courtesy of a pit measuring 0.5 m by 0.5 m and by 0.5 m.

With a potential to save a family about 1,000 yuan ($146) a year, it is estimated more than 100,000 Tibetan households are now making the most of methane gas.

The government began promoting the new fuel in rural areas in 2006 and plans to build 39,468 methane-generating facilities this year.

At the end of 2010, the figure is expected to reach 200,000 across the region.

Puqung, a farmer in Zongxia village in the Tibet autonomous region, uses a methane stove in the kitchen to prepare her family's breakfast.

"We used cow manure for cooking and heating before, but the smell it gave off was so bad I couldn't open my eyes."

The family's stove is now connected to a methane pit in the backyard.

Since the gas came online, the Puqung's kitchen has been much cleaner and much easier on the nose.

"Life is much easier since we don't have to collect livestock manure and firewood any more," Puqung said.

Like her family, almost all households in the large farming village are interested in building methane pits, covered holes in which waste ferments and creates useable gas.

"We are benefiting from the new fuel," Zon'gar, a villager, said.

"It turns waste into treasure."

A cleaner environment and economic profits have made methane pits increasingly popular in rural areas of Tibet.

Jo'nga Cering, an inspector of Tibet's agro-pastoral department, said the regional government has been researching a practicable method of using methane fuel in plateau areas.

"If we build a greenhouse on the methane pit, it ensures the required temperature for fermenting stalks and straws," Jo'nga Cering said. "It proves efficient."

Methane gas not only improves living conditions for farmers and herders it also saves coal and firewood, Jo'nga Cering said.

I get 600mm cube holes dug at a rate of 10 per man per day or about 15 baht. I will bet you right now that these holes will be worth less than that in 3 months time. Same as here, no money, no honey. This article is absolute BS, nothing personal mate

I dont get the point you are trying to make IA.

I found this Chinese article on Google after seeing a programme on BBC depicting a methane pit at a small chinese home. I thought it to be relevant to the thread.

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Ozzy,

If I offended you then that was not my intention and you have my apologies.

But an article on the autonomous region of Tibet where 0.5mtre cube holes are supplying the cooking gas needed ablely assisted by a greenhouse above them and carried out on a "methane" stove is simply not credible.

IA

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  • 11 months later...

Hi - in the US, power utilities pay for biomass power at about $.10 a Kwh, I think I could run a small outfit just to turn a very small profit s proof of concept and then make it bigger later on. I need a consultant/mentor, free ones are better. Step up if you want to help.

Phillip

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  • 5 months later...

Here is my 2 cents worth.

Back in the early 70's I was a part of group out of Seattle, Washington USA, that did a feasibility Study on Anarobic Digesters to make (CH4) Methane Gas out of Bovine waste. The study was funded by a grant fron the US Department of Ecology and we built 2 large (30 foot diameter x 28 foot high) anarobic digesters using, AO Smith Harvestor Slurry Store tanks with floating domes that produced a low pressure gas. The gas was piped into a Johnson Burner that would burn methane gas or fuel oil. If the methane pressure dropped below a certain level, the fuel oil would power the Johnson burner.

Nothing was wasted, as the effluent was either pumped on the growing fields, or dried and bagged at high nitrogen fertilizer. The nitrogen released from the effluent from anaerobic digesters is far better, for most agricultural applications, then aerobic settling ponds. "Nitrogen is considered especially important because of its vital role in plant nutrition and growth. Digested sludge contains nitrogen mainly in the form of ammonium (NH4), whereas nitrogen in aerobic organic wastes (activated sludge, compost) is mostly in oxidized forms (nitrates, nitrites)."

Maybe this will be of some interest too:

Nitrogen Fertilizer Value of various sluges and finished compost.

Nitrogen (%dry wt)

---------------------------------------------------------------------------

Raw Sewage------------------------1.0-3.5

Digested sludge:

10 Municipalities ------------------1.8-3.1

12 Ohio Municipilaties------------0.9-3.0

51 samples 21 cities-------------1.8-2.3

General average-------------------2.0

Activated sludge:

5 Municipitalities-------------------4.3-6.4

General average-------------------4.0-7.0

Digested manure-sludge:

Hog-------------------------------------6.1-9.1

Chicken-------------------------------5.3-9.0

Cow------------------------------------2.7-4.9

Hope all this has been of some interest!

ETC (Jim)

Edited by ETC
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I like many posters on this topic in various threads, have been studying the subject of Bio-gas for some years. I have decided to delay the construction of a biodigester to process the effluent from my pig farm. Recently there has been a lot of research done on the CN Ratios of various feedstocks which indicate low levels in pig manure hence low methane production. A limited and unreliable gas supply would be of little benefit to me and I am yet to resolve a method of adding more vegetable matter or other feedstock to increase gas production without aggravating potential hard scum formation.

I consider the digester as an important part of my total integrated farm planning but not one that is essential. To be honest I find it hard to justify the expense of building and maintaining the digester and gas handling equipment against the cheap price of grid electricity here.

Currently I am reviewing a composting option which would combine rice straw, manure and crop wastes in a vermicomposting environment. My two issues are odours and the need to condition our farm soil.

Isaanaussie

IA

In my previous post on the anaerobic (without air) digesters, I omitted to mention that we found the greatiest benefit of the digesters was not the Methane gas, but rather the readily usuable form of high Nitrogen fertilizer. The Nitrogen from the anaerobic digester is in a much more usuable form for plants then the Nitrogen derived from an aerobic digester (with air); whether applied directly to the fields or dried and bagged as fertilizer.

I would think that LOS has a perfect environment for generating Methane gas, considering the yearly ambient temperature required to keep the sludge active, and the high grade of Nitrogen fertilizer that goes with it. That is one of the projects I will be starting on my return to LOS shortly, as I can see several positive benefits for me, but getting rich from it is not one of them.

ETC (Jim)

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I have an interesting question for anyone who has a biodigester. Have you ever tried using EM in the digester? If so, does it effect the gas output?

I process pig waste water in septic tanks. I recently pumped out the sediment of a tank and after a week or two realised that I had forgotten to dose the tank with EM to control any smell that may occur. When I did I noticed that the sludge blanket on the surface was quite crusty. Yesterday I looked and the sludge was alive with gas bubbles.

Secondly, ETC, I have noticed a large difference in bottled gas prices here in Isaan. Almost twice what we paid around Bangkok. We dont use enough gas to make the investment worthwhile but you may well find that the returns from gas sales outside the large cities could provide a steady income.

Isaanaussie

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I have an interesting question for anyone who has a biodigester. Have you ever tried using EM in the digester? If so, does it effect the gas output?

I process pig waste water in septic tanks. I recently pumped out the sediment of a tank and after a week or two realised that I had forgotten to dose the tank with EM to control any smell that may occur. When I did I noticed that the sludge blanket on the surface was quite crusty. Yesterday I looked and the sludge was alive with gas bubbles.

Secondly, ETC, I have noticed a large difference in bottled gas prices here in Isaan. Almost twice what we paid around Bangkok. We dont use enough gas to make the investment worthwhile but you may well find that the returns from gas sales outside the large cities could provide a steady income.

Isaanaussie

IA

Good question. I'm not familiar with EM's being applied to biodigesters, but I have considerable experience with small bio-reactors to raise super Microbials for contaminated soil remediation. It is an interesting idea and maybe the EM acts as and exciter for other Microbials. In normal practice, super microbials are used for soil remediation, but the trick was to shorten the total time for total soil remediation of petrolieum contaminated soil. That is where I trained my focus and I found a formula of elements to excite the super Microbials to do the total soil remediation in, in some cases, half the time and at a fraction of the cost of the accepted method of removing all the soil from the contaminated area. The microbial procedure is environmentaly friendly and can be done right up against protected wetlands. I would think LOS would be perfect for microbial applications, do to the yearly ambient temperatures, as the microbials will go dormant if they get to cold.

As for bottled gas; creating the gas should be the easy part, the hard part is getting it to the consumers. I remember many years ago when we made methane demo models, we used large tractor inner-tubes to store the gas, but I cannot see that as a viable option. The operations I am familiar with deal with onsite production and usuage of the methane gas by way of low-pressure pipe lines. I will give that some serious thought and see what I can come up with.

Thank you for the information IA.

ETC (Jim)

Edited by ETC
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This is a decent read

www.homepower.com/files/methane.pdf

The below is condensed from many sources (compiled mid 2006)...

Biogas-Methane-Properties-Production-Use

+ Methane Properties

-> Methane (CH4)

-> is very light at .55:1 to air, odorless, colorless, tasteless

-> The flash point of methane is -369 Fahrenheit or -223 Celsius

-> The boiling point of methane is -260 Fahrenheit or -162 Celsius

-> The auto-ignition temperature of methane is 999 Fahrenheit or 537 Celsius

-> Paper scorches and turns brown at about 450 Fahrenheit.

-> Methane has a flammability range of 5% to 15% in air

-> That means that over 15% methane in air will not ignite.

-> Compressed and stored in the tank

segregation of methane, nitrogen and oxygen occurs

-> As methane is drawn off, and nearing tank depletion,

methane percentage to air can approach 5% to 15%, and explosion can occur

-> Methane gas cools on expansion through a nozzle.

-> It will not ignite when it expands out a nozzle, it will require an ignition source.

-> Any spark or energy source will ignite the methane.

-> Liquefaction of methane is high tech. To liquidfy "pure" methane (LNG) requires

-> psi >1110

-> Temp below -160 F (above this temp it will never liquidfy)

-> note, trace gases modify these parameters

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

+ Production, Method type and flow

-> Methane Digester, constant flow, dual stage (2 tank horizontal layout)

(the better system is to have 2 Digester production units)

-> Production Feedstock = pig \ cow excrement

-> how much is required depends on the system and tank size...

-> Daily (or weekly) in a "constant flow" type system or

-> Every 3~4 months in a "static" type system.

+ Production Issues

-> odor, smell during production = controllable

-> maintain temp of digester unit within range of 85` ~ 105` F (95` F is perfect)

-> use waste heat from engines, passive solar (with maybe thermal cistern)

-> must scrub and dry gas at source, before compression pump

-> remove trace hydrogen sulfides (mixed with water = Corrosive Sulfuric Acid)

-> I've seen where

engine temp =+ 195` negates the acid problem (this removes the water)

-> Over-Production of Methane Gas can be a significant issue

-> see the section on storage

-> what to do with over-production?

-> burn it off (far better than releasing into the atmosphere)

-> give it away, (probably can't sell it due to gov regulations)

+ Production By-Products and Issues

-> The Cow/Pig Dung slurry is a nitrogen rich organic fertilizer

-> It has an odor

-> Disposal of the Cow/Pig Dung slurry

-> Sell or give it away in bulk

-> Provide a service to spray it on crops, fields, pastures

(note equipment needed)

-> unknown how long after application does the odor linger

-> May be health issues of using it on gardens, and

-> Will be gov regulations requiring compliance

+ Methane Storage and Issues

-> Commercial Quantity Distribution, Storage and Transport

-> as LNG (not LPG),

compressed to >2,500 psi and cooled to > -165` F with Liquid Nitrogen

-> shipped in racks of cylinders,

made from large heavy gauge steel or composite epoxy-carbon

-> as CNG, Commercial Automobile Fuel

-> as Gas, compressed to >2,500 psi, not cooled

-> stored in cylinders,

made from heavy gauge steel (scuba type) or composite epoxy-carbon

(these are very different than cylinders used for LPG fueled cars

-> Do-It-Yourself Storage, Transport

-> for all uses, engine fuel, cooking, lighting, heating

-> as Gas, compressed to around <300 psi with shop AC compressor(s)

-> stored in common standard propane or LPG cylinders

-> requires many cylinders

(note the implied gas over-production and logistical issues)

-> note, not very practical for cars @ 300 psi

= small qty of methane = limited distance (see below)

+ Methane as Engine Fuel and Issues

+ Biogas Methane Percentages and BTU

-> Internal Combustion Engines require

18 cubic feet of methane per horse-power per hour

-> About 225 cubic feet of methane gas

equals one gallon of gasoline (@ sea level).

(above if for commercial CNG)

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

-> odor, smell during combustion = none

+ Methane as Engine Fuel Issues

-> EFI engines will likely have issues with the computer adjustments (re-chip)

-> No catalytic converter issues from resulting compounds of combustion

-> No exhaust oxygen sensor issues from resulting compounds of combustion

-> Increased engine emissions output = increased o2 and NitOx

-> Corrosion Issue =

trace hydrogen sulfide mixed with water = Corrosive Sulfuric Acid

-> Scrub and dry gas (at source before compression and storage)

-> Using a gas membrane separator or

-> Bubble methane gas through column of

CaCO3 (calcium carbonate, or limestone) slurry

-> i've seen where engine coolant temps @ +195' F avoids the water formation

but is likely still present in the exhaust system

-> Range of engine compression ratio for methane use is 8:1 to 20:1

-> Perfect compression ratio = 15:1

-> For gasoline engines...

-> Compression can be raise slightly with a turbo or blower

-> For diesel engines - usually no problem for idi or di

-> Injecting Methane Gas

-> For gasoline engines, Carbed or TBI

-> below the butterfly valve is preferred

-> drill the base of the carb base or use drilled spacer plate

-> For gasoline engines with Direct Injection

-> after the throttle butterfly valve is preferred

-> For diesel engines, idi or di

-> after the throttle butterfly valve is preferred

-> note this is an amendment to the incoming air or

the diesel needs a spark ignition (a major engine modification)

+ Methane as Cooking Fuel Issues

-> all Thailand cooking burners are set up to use LPG.

They will have a small pill size (orifice).

They will require modification to use biogas...

both in orifice size and the fuel/air mixture ratio.

One cannot switch back 'n forth between the fuels without issues.

To use LPG is a stove setup for biogas is very, very dangerous.

I don't know but suspect that

1 tank of LPG = 15~20 tanks of biogas (pig manure)

"One cannot switch back 'n forth between the fuels without issues."

Methane generation and usuage projects that I have been envolved with use a Johnson Burner. The main source of fuel was the low-pressure methane gas and when the pressure dropped below a certain level, the fuel oil source would kick in. It worked rather well actually.

ETC (Jim)

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This is a decent read

www.homepower.com/files/methane.pdf

The below is condensed from many sources (compiled mid 2006)...

Biogas-Methane-Properties-Production-Use

+ Methane Properties

-> Methane (CH4)

-> is very light at .55:1 to air, odorless, colorless, tasteless

-> The flash point of methane is -369 Fahrenheit or -223 Celsius

-> The boiling point of methane is -260 Fahrenheit or -162 Celsius

-> The auto-ignition temperature of methane is 999 Fahrenheit or 537 Celsius

-> Paper scorches and turns brown at about 450 Fahrenheit.

-> Methane has a flammability range of 5% to 15% in air

-> That means that over 15% methane in air will not ignite.

-> Compressed and stored in the tank

segregation of methane, nitrogen and oxygen occurs

-> As methane is drawn off, and nearing tank depletion,

methane percentage to air can approach 5% to 15%, and explosion can occur

-> Methane gas cools on expansion through a nozzle.

-> It will not ignite when it expands out a nozzle, it will require an ignition source.

-> Any spark or energy source will ignite the methane.

-> Liquefaction of methane is high tech. To liquidfy "pure" methane (LNG) requires

-> psi >1110

-> Temp below -160 F (above this temp it will never liquidfy)

-> note, trace gases modify these parameters

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

+ Production, Method type and flow

-> Methane Digester, constant flow, dual stage (2 tank horizontal layout)

(the better system is to have 2 Digester production units)

-> Production Feedstock = pig \ cow excrement

-> how much is required depends on the system and tank size...

-> Daily (or weekly) in a "constant flow" type system or

-> Every 3~4 months in a "static" type system.

+ Production Issues

-> odor, smell during production = controllable

-> maintain temp of digester unit within range of 85` ~ 105` F (95` F is perfect)

-> use waste heat from engines, passive solar (with maybe thermal cistern)

-> must scrub and dry gas at source, before compression pump

-> remove trace hydrogen sulfides (mixed with water = Corrosive Sulfuric Acid)

-> I've seen where

engine temp =+ 195` negates the acid problem (this removes the water)

-> Over-Production of Methane Gas can be a significant issue

-> see the section on storage

-> what to do with over-production?

-> burn it off (far better than releasing into the atmosphere)

-> give it away, (probably can't sell it due to gov regulations)

+ Production By-Products and Issues

-> The Cow/Pig Dung slurry is a nitrogen rich organic fertilizer

-> It has an odor

-> Disposal of the Cow/Pig Dung slurry

-> Sell or give it away in bulk

-> Provide a service to spray it on crops, fields, pastures

(note equipment needed)

-> unknown how long after application does the odor linger

-> May be health issues of using it on gardens, and

-> Will be gov regulations requiring compliance

+ Methane Storage and Issues

-> Commercial Quantity Distribution, Storage and Transport

-> as LNG (not LPG),

compressed to >2,500 psi and cooled to > -165` F with Liquid Nitrogen

-> shipped in racks of cylinders,

made from large heavy gauge steel or composite epoxy-carbon

-> as CNG, Commercial Automobile Fuel

-> as Gas, compressed to >2,500 psi, not cooled

-> stored in cylinders,

made from heavy gauge steel (scuba type) or composite epoxy-carbon

(these are very different than cylinders used for LPG fueled cars

-> Do-It-Yourself Storage, Transport

-> for all uses, engine fuel, cooking, lighting, heating

-> as Gas, compressed to around <300 psi with shop AC compressor(s)

-> stored in common standard propane or LPG cylinders

-> requires many cylinders

(note the implied gas over-production and logistical issues)

-> note, not very practical for cars @ 300 psi

= small qty of methane = limited distance (see below)

+ Methane as Engine Fuel and Issues

+ Biogas Methane Percentages and BTU

-> Internal Combustion Engines require

18 cubic feet of methane per horse-power per hour

-> About 225 cubic feet of methane gas

equals one gallon of gasoline (@ sea level).

(above if for commercial CNG)

-> Natural Gas (commercial)

-> BTU = about 1,000 per cu-ft

-> 80% methane, 10-55% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> no trace hydrogen sulfides

-> BioGas (Pig or Cow Dung)

-> BTU = about 600-700 per cu-ft

-> 55-70% methane, 30-35% carbon dioxide,

some hydrogen, nitrogen and other trace gases.

-> trace hydrogen sulfide (mixed with water = Corrosive Sulfuric Acid)

-> odor, smell during combustion = none

+ Methane as Engine Fuel Issues

-> EFI engines will likely have issues with the computer adjustments (re-chip)

-> No catalytic converter issues from resulting compounds of combustion

-> No exhaust oxygen sensor issues from resulting compounds of combustion

-> Increased engine emissions output = increased o2 and NitOx

-> Corrosion Issue =

trace hydrogen sulfide mixed with water = Corrosive Sulfuric Acid

-> Scrub and dry gas (at source before compression and storage)

-> Using a gas membrane separator or

-> Bubble methane gas through column of

CaCO3 (calcium carbonate, or limestone) slurry

-> i've seen where engine coolant temps @ +195' F avoids the water formation

but is likely still present in the exhaust system

-> Range of engine compression ratio for methane use is 8:1 to 20:1

-> Perfect compression ratio = 15:1

-> For gasoline engines...

-> Compression can be raise slightly with a turbo or blower

-> For diesel engines - usually no problem for idi or di

-> Injecting Methane Gas

-> For gasoline engines, Carbed or TBI

-> below the butterfly valve is preferred

-> drill the base of the carb base or use drilled spacer plate

-> For gasoline engines with Direct Injection

-> after the throttle butterfly valve is preferred

-> For diesel engines, idi or di

-> after the throttle butterfly valve is preferred

-> note this is an amendment to the incoming air or

the diesel needs a spark ignition (a major engine modification)

+ Methane as Cooking Fuel Issues

-> all Thailand cooking burners are set up to use LPG.

They will have a small pill size (orifice).

They will require modification to use biogas...

both in orifice size and the fuel/air mixture ratio.

One cannot switch back 'n forth between the fuels without issues.

To use LPG is a stove setup for biogas is very, very dangerous.

I don't know but suspect that

1 tank of LPG = 15~20 tanks of biogas (pig manure)

"One cannot switch back 'n forth between the fuels without issues."

Methane generation and usuage projects that I have been envolved with use a Johnson Burner. The main source of fuel was the low-pressure methane gas and when the pressure dropped below a certain level, the fuel oil source would kick in. It worked rather well actually.

ETC (Jim)

One of the conclusions derived from our project, was that the focus must be on either gas or electricity, to reap the greatiest benefit overall.

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