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natural compressed gas

natural compressed gas

natural compressed gas

(OP)
OK GUYS, I'M NEW HERE AND AN OLD MAN, SO PLEASE BE GENTAL,LOL
WHAT I WOULD LIKE YOUR INPUT ON IS ............ IS IT FEASABLE TO HAVE A NATURAL GAS WELL AND COMPRESS THE GAS AND USE IT FOR MY CAR? WHAT DO YOU THINK? THANKS.

RE: natural compressed gas

First, STOP SHOUTING, we can "hear" just fine in lower case.

The most effective natural gas powered engines are converted diesels because you need the extra compression to get the fuel dense enough to compete with petrol. You can run a gasoline (petrol) engine on natural gas, but you pay a significant loss of power.

If you "just" want to drill a gas well out back (and you have the mineral rights and you have the expertise and you have the equipment) then mother nature will give you what she gives you. That can include H2S (poison gas), CO2 (won't burn), liquid hydrocarbons (need further processing before they're useful to you), etc. Then if you are looking to use CNG you need equipment to compress it up to over 3600 psig and vessels to hold high pressure gas. At the end of the day, a "typical" 3000 ft deep well, separation equipment, deliquification equipment, storage equipment and compression equipment should cost you about $2 million. At $4/gallon and 20 miles/gallon the payout is 10 million miles.

Good luck.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

(OP)
i guess i wasn't plain enough, i am looking at some property that has a gas well on it and what i want to do is to compress it enough (ncg)to put a tank in my car to run it, if there is an easy to do it, or maybe run a stationary engine for a generator, does that make more sence?

RE: natural compressed gas

are you an engineer?
easy is really not appropriate as natural gas is a flammable gas, a gas not to be taken lightly or by the average human. the recommended course of action is to seek a responsible and competent engineer. so you know, the practice of compressing natural gas for auto usage is widespread and the equipment is available. it is a matter of being knowledgeable & capable of designing a system to meet your needs.
but before you do this, please read zdas04 response about the engine output power + other possible requirements. zdas04 is one saavy sourdough engr. you may want to change your mind.

-pmover

RE: natural compressed gas

Are you buying the property with mineral and production rights? If not, forget about it. If you have mineral rights, it's still not the end of the story. Is the well is plugged? You'll have to ... well open it.... somehow. Does the state, or the Feds own the royalties? You'll have to pay for it. The state and the feds have production forms to fill out every month. You'll have to be an approved operator. You'll have to conform to the production quota? You may have to pay a good faith deposit, so you will plug it properly when it runs out of gas. You have a safety program? You have wet gas, nitrogen, CO2? You don't just go out and turn the valve on.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

RE: natural compressed gas

(OP)
but that is just what you do, turn the valve on and the gas is there, there several wells there and every one runs there house on gas, you own the wells and what comes out of them, i just want to go one step further and compress it for power, and thats a good point ,do the feds own any part of it, i will ck. it out before i buy, thanks

RE: natural compressed gas

You can't use a diesel egine on natural gas, you have to have a spark ignition system. Many car companies now make CNG versions of their existing cars.

The EPA regulates conversion of an engine from gasoline to natural gas. Therefore all modifications must be tested to assure that the modification meets rules. Because of this, there are companies that make conversion kits that have been tested, but they only make them for very popular cars and trucks. You can google up and see that kits for Ford F150 trucks and Chevy trucks are available.

Once you have done the conversion, google up CNG compressors. They are pricey, but typically you take 8 hours to fill the compressed gas tank.

Gas quality can be an issue like what has been stated above, but even worse is the WATER in the gas. If you do not remove the water, when you let the pressure down from tank pressure to injection pressure, the line will freeze and you are at a dead stop.

RE: natural compressed gas

(OP)
MY THOUGHT WAS TO INSTALL A 100 GAL CNG TANK AND USE IT TO FILL THE CAR AND GEN. UNIT
MAYBE WILL HAVE TO USE DRYER? THANKS FOR THE INFO.......

RE: natural compressed gas

dcasto,
Virtually all the field natural gas engines that I see are diesel conversions--that is you start with a diesel engine to get the compression ratios and then add a spark ignition system. There are exceptions like the Compressco and some GM and Ford industrial engines, but they are all very horsepower limited (e.g., the Compressco is half a Ford V-8 which is 300 hp as a V-8 on gasoline and 30 hp as a straight 4 on natural gas).

Natural gas conversion kits for gasoline engines pay a horrible price in terms of lost power. That is what I said above.

The built for purpose CNG engines have high compression ratios.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

Whatever you do with the gas, you're probably all going to face some charges, if the regulatory authorities, real owners, or the tax man finds out about it.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

RE: natural compressed gas

(OP)
WOW, IS THERE NO HOPE? LOL I GUESS I NEED A LOT MORE INFO. BEFORE I MAKE ANY PLANS....................THANKS DON

RE: natural compressed gas

I wasn't trying to say that there is no hope, just that it isn't such a simple job as opening the valve, even if you do own the gas and it's clean and dry. Regulations and taxes will get you if nobody else does.

There may be hope that somebody doesn't find out, but I have found that it is just a matter of time that they do. The more time, the worse the final result.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

RE: natural compressed gas

There are companies selling CNG vehicles - Honda has a Civic model and there are lots of commercially available conversion kits. Ford & GM will sell you a truck through their dealerships that has a factory warranty although the conversion is done by a 3rd party.

You can by a home compressor. I think these are intended to be connected to a commercial source of clean natural gas so you would probably need to add various filters/water separators.

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

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: natural compressed gas

I'm sure that the available compressor equipment takes the temperature change into account. As I recall, many of those CNG powered vehicles store the gas at very high pressures, like 10,000 psi. If you pull it out of the ground at 1000 psi and compress it to 10,000 psi, you get a significant increase in temperature. I suspect the professional equipment includes a lot of heat removal features designed into it.

Doug

RE: natural compressed gas

Your numbers are a bit off. Typically, a "full" CNG tank is at 3600 psig. It has become quite rare for a well to have 1000 psig wellhead pressure. Some of the new shale plays see pressure significantly above 1000 psig for several years, but they are not something you "find in the backyard of a property you're purchasing". Older wells in older formations tend to have wellhead pressures closer to 25 psig and many will be lower. That is why the wellhead compressor market is flourishing in spite of very low product prices.

So if you go straight from a 25 psig well into a 3600 psig vehicle tank you need to do something like 104 compression ratios--heat of compression would take 80°F gas up to 1032°F if there was any way to do it in one stage (there isn't). This would be a pretty good 4 stage application, but I'd probably design it as a 5-stage to make sure that I could get into the tank when it is almost full.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

with interstage coolers.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

RE: natural compressed gas

Try and read the article i referred to. It actually contains a lot of info re. conversion, somethings on rules, equipment for loading etc including cost.

RE: natural compressed gas

Oh yes, and pay attention to the first couple of lines where its stated that if you "do-it-yourself" then its a violation of the clean air act and will cost you a fine of $5000/a day you drive the car. Im not a subject expert but it seems from the article that the quality of the DIY installation is insignificant wrt the violation - its the certificate that matters.

Best regards

Morten

RE: natural compressed gas

zdas, no to be argumentative, but the cat engines say 3500 series, the diesel version has a 14 to 1 compression ratio and the nat gas TA (turbo) series has an 8 to 1 compression ratio and a a NA (naturally asperated) can run from 9 to 1 to 11 to 1. The diesel version of the same engine has a compression ratio of 14 to 1.

The block and crank are about the only simularities between a diesel cat and a nat gas cat. The difference is the BMEP, the diesel is higher because it has such a high CR.

RE: natural compressed gas

The compression ratio data you mention is right, I've never looked at it up before. When we (Amoco in Farmington) had such horrible power on CNG, the Amoco Engineer responsible for the project did some research and said that the problem was low compression ratios and we pulled the conversion kits and sold the compressor. That is as far as I got.

The performance we saw was awful. Pulling a 6500 lbm trailer in a 1 ton truck up a reasonably shallow, but very long hill. On CNG the truck was in first gear and was running out of power at 5 mph. We flipped the switch to gasoline and by the top of the hill we were at the speed limit in 4th gear. CNG tank pressure was over 3000 psig. These were top of the line conversion kits and everyone had a great deal of interest in making it work (the pumper with the lowest gasoline to CNG ratio at the end of each month got a bonus).

Any idea of an alternative explanation for the poor performance?

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

ZDAS
Without further understanding the complete fuel system it's hard to speculate on the reason for the lack of power. If I had to guess the conversion was the old style with a mixer mounted to the throttlebody. I would guess if it a good conversion with a dual ECM and NG injectors you wouldn't have seen that drop off in power. Generally on NG spark maps are radically different from gasoline.
I've been involved in late model GM NG conversions where you couldn't detect the difference between Gasoline and NG without looking at the switch.

RE: natural compressed gas

So it is a timing issue instead of a fuel density issue?

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

there is also the difference in stoich AFR - if you're trying to run near stoich w/gasoline at 14.7:1 and w/nat gas at 16.8:1, and you're putting the same amount of air in per cycle, then you'd have 12% less fuel mass into the engine per cycle w/cng.
...but you'd make it up on the LHV difference (47.141kJ/kg methane vs. 43.448kJ/kg gasoline)
...of course, the gaseous CNG will displace a heck of a lot more air in-cylinder than the liquid gasoline will, so you'll end up getting less air in. At STP, gasoline 719.7 kg/m3 and methane is 0.7 kg/m3... when the cylinder is full at stoich, gasoline takes up 0.0001/1 of the space, and cng takes 0.0929/1 of the space.
...If you have 1l/cyl displacement, operating at stoich and considering all of the above, you get about 3.07 kJ/cycle from your CNG and about 3.56 kJ/cycle from gasoline. That gives about 14% reduction in power.

if you compare the specs on the "regular" honda to the CNG version, you'll see that the power is down significantly, and compression ratio is up significantly... a 19% reduction in power. I would assume that timing is optimal in each case. Not sure where the rest of the lost power comes from.

DX Coupe
Engine Specifications
1.8L 140 hp I4
Horsepower 140 @ 6300 RPM
Torque (lb-ft) 128 @ 4300 RPM
Fuel Type/System Gasoline/MPFI
Valves/Valve Configuration 16/SOHC
Displacement (cc) 1799
Bore X Stroke (in.) 3.19 X 3.44
Compression Ratio 10.5:1
Turbocharger No
Supercharger No

GX sedan
1.8L 113 hp I4
Horsepower 113 @ 6300 RPM
Torque (lb-ft) 109 @ 4300 RPM
Fuel Type/System Compressed Natural Gas/MPFI
Valves/Valve Configuration 16/SOHC
Displacement (cc) 1799
Bore X Stroke (in.) 3.19 X 3.44
Compression Ratio 12.5:1
Turbocharger No
Supercharger No

RE: natural compressed gas

Thank you for that. 14.8% lower torque at 4300 rpm explains a lot about the performance we saw.

Your explanation also helps me get my head around why the guys doing an LNG test the same time we were doing the CNG test had no noticeable power reduction.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: natural compressed gas

Sorry i'm late jumping in. Well head natural gas is loaded with contaminates so with a good diesel filter it is great for homes or sheds. If you want to spend the money to clean and compress you should just continue to buy gas made from my crude. Oh and if you own the well do with it what you please with one exception, your state government most likely has a motor fuel tax so a chat with your local regulators could save you from getting taxed oh so kindly for every mile on your vehicle

RE: natural compressed gas

Zadas04, Ivymike got most of the differences between gasoline and gasoline in a spark ignition engine. The other factor is related to the compression ratio and torque. Since methane has an octane rating of over 100, you could run a spark ignition engine upwards of 12.5 to 1 ration with methane, that alone would get back more than 15% more torque than a typical 9 to 1 comprssion.

Look up the HP difference on the plain ol 2.5 liter Subie and one that uses a turbo to artifically increase HP. Plain ol subie, 175 HP, simple turbo that is equal to a 11 to 1 compression ration, 250HP

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