A few years ago, I managed to get myself on a mailing list from a fellow who fancied himself an expert on energy. Actually, it seemed that no area was beyond his expertise, and the fact that EVERY EMAIL FROM HIM CAME WITH A SUBJECT LINE IN CAPS WITH A LOT OF EXCLAMATION POINTS!!!! really sealed the deal on his bona fides. One of the facts he liked to tout was that natural gas was the perfect fuel. Not only is it clean-burning and relatively cheap, it’s also delivered directly to consumers using a completely self-powered grid. Even under “zombie apocalypse” conditions, he claimed that natural gas would continue to flow.
At the time, it seemed a bit overstated, but I figured that there was at least a nugget of truth to it — enough so that I converted from an electric range and water heater to gas-powered appliances a couple of years ago, and added gas fireplaces for supplemental heat. I just sort of took it for granted that the gas would flow, at least until the recent kerfuffle over the Nordstream pipeline. That’s when I got a look at pictures of the immense turbine compressors needed to run that pipeline, the size and complexity of which seem to put the lie to claims about the self-powered nature of natural gas grids.
Surely a system dependent on such equipment could not be entirely self-powered, right? This question and others swirled doubt in my mind, and so I did what I always do in these cases: I decided to write an article so I could look into the details. Here’s what I found out about how natural gas distribution works, at least in North America.
Gathering In
Assessing the claims of my all-caps interlocutor requires a basic understanding of oil field geology. Something like 12% of natural gas production in the US in 2018 was from so-called associated dissolved sources, in which the natural gas is a byproduct of oil production. Associated gas was once, and often still is, considered a nuisance that was either vented to the atmosphere or flared off at the well. Associated gas is often dissolved into the liquid phase within the crude oil reservoir, in much the same way that carbon dioxide is dissolved into the liquid in a bottle of soda. And just like when you uncap a soda bottle suddenly, the natural gas dissolved into crude oil can bubble out of solution when the reservoir is tapped by drilling. Associated natural gas can also be a gas phase that exists in a crude oil reservoir but is not dissolved into the liquid phase.
On the other hand, some natural gas reservoirs are non-associated, where the gas is found without any significant crude oil present. Non-associated natural gas is often found where an impervious rock layer forms a cap over a porous rock like sandstone, through which the gas produced by decaying fossil vegetation filters. These reservoirs are often under significant pressure too, making it easy to extract once the reservoir is tapped. There are other types of natural gas reservoirs in the broad non-associated category, like shale gas and coalbed gas.
No matter what the type, exploitation of a natural gas reservoir starts with drilling a well and connecting it to a network of gathering pipelines. These pipes form an immense network that connects thousands of wells to upstream processing and pipeline systems. Depending on the type of reservoir, gathering pipes can conduct either raw natural gas or liquid crude oil. The US on-shore gathering network has about 240,000 miles (386,000 km) of pipe — enough to cover the distance to the Moon.
Cleaning It Up
Raw natural gas usually has much more than just methane in it. Depending on the reservoir type, natural gas can range from a mix of methane, propane, and butane along with other gasses like water vapor, carbon dioxide, and even helium, to an emulsion of crude oil and water foamed up with gas. Most natural gas wells need at least some processing before entering the gathering system, using a device called a gas production unit, or GPU. These machines are essentially adapters between the high-pressure gas in the reservoir and the lower pressures used in the gathering system. GPUs drop the gas pressure with a choke, but to prevent the sudden drop in pressure from cooling the gas mixture to the point where it freezes, the GPU heats the process gas. On the low-pressure side of the GPU, a horizontal separator lets water and liquid hydrocarbons settle out, while the gas phase rises. Some of the gas is tapped off as instrument gas, which is burned to provide the heat for the first stage of the GPU.
Instrument gas is one of the first examples of the self-powered nature of the natural gas grid. Instrument gas is tapped off to power all sorts of equipment along the entire system, parts of which are often very remote and well beyond the practical reach of the electrical grid. In addition to being burned for processes that require heat, instrument gas can be used to run generators that provide backup power for electrical components. The pressure of raw natural gas is also sometimes used to run turbine pumps, and often to pressurize reservoirs and force products to the surface.
Under Pressure
Water is a constant problem for pipeline operations. Even non-associated deposits classified as “dry gas” reservoirs will usually contain at least some water vapor, which could condense within a pipeline and cause internal corrosion, or potentially freeze and occlude a pipe. Dehydrating natural gas is an important step in getting gas ready for the transmission pipeline system. Natural gas is often dehydrated using a chemical treatment process that exposes the wet gas to triethylene glycol, or TEG. TEG is highly hygroscopic, and is used in tall dehydrator towers that are filled with horizontal trays. TEG enters the top of the tower and flows down each tray, while wet natural gas enters the bottom of the tower. The gas bubbles through the TEG, which absorbs the dissolved water vapor. Dehydrated gas exits the top of the tower, while the wet TEG flows out the bottom to a reformer, which uses instrument gas to power burners that heat the liquid to drive off the water, leaving the TEG ready to use again.
After the natural gas is dried and any contaminating propane or butane is removed, it’s ready to enter the transmission system. The transmission system is the long-haul transportation system for bulk gas, consisting of large-diameter, high-pressure pipelines. In the US, there are both interstate and intrastate pipelines, with a total length of about 3 million miles (4.8 million km) that carry about 2.7 trillion cubic feet (76 billion cubic meters) of gas each year.
Transmission pipelines operate at anywhere from 200 to 1,500 psi (1.3 to 10.3 MPa). To achieve the pressure and flow rate to efficiently transport the gas, and to make up for the pressure losses resulting from customer usage and those incurred by pipeline friction, transmission pipelines use compressor stations along the line. Most transmission compressors are powered by gas turbines, which are powered by the very natural gas that is being shipped. Compressor stations tap natural gas from the high-pressure side to power the gas turbine engine, which in turn powers the compressor — another example of the self-powered nature of the natural gas grid. Of course compressor stations require electricity, too, which is provided by the regular electrical grid, or by backup generators that are powered by natural gas. Compressor stations located beyond the electrical grid will often run completely off gas-powered generators.
To The Customers
While some natural gas customers, like power plants and large-scale chemical plants, can be serviced directly off the high-pressure distribution system, most end-users are actually serviced by a local distribution company, or LDC. These operators maintain the local network of gas mains, laterals, and metering devices that snake under the streets of most cities. LDCs maintain one or more connections to the natural gas transmission system, and use regulators to lower the gas pressure within their system and flowmeters to measure gas usage. LDCs are also responsible for injecting the methyl mercaptan odorant that gives natural gas its characteristic smell.
By and large, the pressure regulation and metering done by LDCs are mechanical in nature; regulators tend to use diaphragms and springs to reduce the pressure in a main to the very low pressure, often just a fraction of a psi, used by many gas appliances. Metering methods vary, but the meters for residential and commercial customers are often powered by bellows expanding under gas pressure to tally up the flow of gas.
Like transmission pipeline operators, LDCs rely on electricity to power quite a bit of their equipment, including monitoring and control gear. And in most cases, the LDCs are connected to the grid just like everyone else. Like the transmission operators, they’ve also got natural gas-fired backup generators in case of local outages, but almost all of the major distribution functions are powered by the pressure of the natural gas itself.
So, while there’s far more to the story than Mr. All-Caps let on, it looks like he wasn’t far off the truth. The natural gas grid really is largely self-powered and engineered to keep on working no matter what.
Thank you for including sane and scientifically correct SI units in the article! I can always to MPa into bar easily on my wetware CPU. psi should be abandoned for good.
1 bar ~ 1 atm ~ 15 psi, cake. It like DN50 being a 2″ pipe, also cake.
But yeah, lets retool entire industries because you can’t compute it in your head.
it’s 14.7psi
Yes which, if you round to 2 digits, is 15 psi. ‘~’ means approximately. Perfectly acceptable as a rough estimate if you’re aware of the limitations.
Nade is probably the guy who would crash another Mars Climate Orbiter. You trivialise it and create awfully huge errors with this naive simplification:
1 bar = 0.986923 atm
1 bar = 14.5038 psi
If I would calculate so inaccurate my boss would compliment me out of the building with his boots. But it would appear you *attempted* to look cool :^)
In most engineering, 5% accuracy is excellent. Two digits of precision is just fooling yourself that you – or rather your field technician, your sensors etc. – can even measure the difference.
Of course they can, if proper procedure is followed and the tools are calibrated, but the point is you can’t trust a guy with a vernier caliper who says “14.52 mm”.
It seems you’ve entirely missed the point. We’re not doing engineering here, and your 6 sig fig conversions are worthless with a figure that starts at only a few sig figs and is being used only to compare the scales of pressure. But do go ahead and convert 10MPa using your 6 sig figs and then tell us if it is indeed higher pressure than consumer gas pipes. Or maybe it isn’t once you’ve done an accurate conversion?!
There’s a time and a place for accurate conversions, but this isn’t it.
I’m suddenly reminded of a crime thriller plot where the villain hacked into the banking system and started re-directing all the rounding errors into his secret account.
Dude: Repeated forever in various movies. Office space even refs superman.
The actual event happened in the early 1970s in Canada. It wasn’t illegal and banks had been truncating and keeping if for themselves. Guy kept the money.
That is my life’s ambition. Invent a new crime. Damn Computer fraud and abuse act makes anything some bendejo judge doesn’t like retroactively illegal though.
Gas industry seems to like to use a mixture of roman numerals and freedom units:
MMSCFD [million standard cubic feet per day]
So if you’ve lost your sense of smell due to COVID then you have no idea whether or not you have a gas leak. If this is the case you really should get a sensor.
Overall a great article there are a couple of weak points that could have been made clearer in the article. Odorant injection at the LDC level requires on site tanks and tanker trucks for delivery. Depending on size of station the tank last anywhere from 3 months to 3 years for small stations used for winter peak shaving. Pressure regulators require annual maintenance to replace or clean diaphragms but occasionally pipe scale, compressor oil or other foreign matter prevent regulators from closing which can cause pressure to exceed piping specification downstream of the regulator. LDC’s have gas controllers to monitor the system 24/7 to make sure pressures, temperatures and Odorant injection rates are within compliance levels.
The gas system is fairly resilient and mostly mechanical but requires monitoring and maintenance 24/7 to ensure safe reliable gas delivery. Like most systems if there is a zombie apocalypse the gas system will fail spectacularly but overall it is a very reliable system.
Protip : To check if you have a gas leak, just light a match and you will know it blazing-fast !
Actual science: natural gas is explosive only in a fairly narrow range of dilutions in air. It’s very possible to have a leak that doesn’t result in an explosive mix. Thankfully. This does mean that it’s possible for a gas leak to exist for long months.
A major movement on the New Madrid would disrupt the NG distribution system and not be “quick fix’.
If you read between the lines, you can deduce from the article that natural gas is methane (or primarily methane) when delivered to the end user. Does this sound right? This is new information for me.
Indeed, anyone sending regular emails IN ALL CAPS and WITH MORE THEN ONE EXCLAMATION MARK should be sharply discounted, at least in my opinion. I would probably unsubscribe the first day.
I’ve spent the last 8 or 9 year working various natural gas projects and yeah, you’re essentially correct. Methan makes up around 80-90% of natural gas on average and is actually scentless. The smell most people associate gas with is actually Mercaptan which is typically added to the gas on the distribution side of the network before heading to the end users.
What chemical is responsible for the smell of intestinal gas?
I think it’s hydrogen sulfide. However, Wikipedia says intestinal gas contains more methane than H2S.
Do I need to plug a reservoir to my butt to start harvesting farts and then filter out unwanted product before using the final gas in my appliances? Or not economical or impractical?????
It’s Methanethiol and Dimethyl sulfide, both produced by anaerobic bacteria in the gut. If you want to produce more, eat garlic, asparagus and cabbage.
Hackaday titles are all caps…
B^)
Some would say Hackaday titles are all crap…
B^)
That’s not fair. They have a whole department dedicated to writing the titles full of alliteration.
B^)
“Hackaday titles are all caps.” Actually, as you say on the Internet when you’re about to point out something that’s technically true but entirely moot…
Our titles are in title case, but the font that it’s styled in is all caps. Check the HTML if you don’t believe me.
Even stranger, whether a copy/paste is in the original case or the all-upper font case varies from browser to browser. Freaky!
But, oh yeah. Sick burn! :)
“title case”, hmmm, a new term for me.
Thanks
MS Word used to have a title case option in “change case” but for some reason dropped it several versions ago. I think WP also had one.
Yes, right now near me in the midwestern US it is about 85% methane, 11% ethane, 2% Nitrogen, 1% CO2, 0.7% Propane, the rest traces of heavier hydrocarbons. And the BTU content is 1073/cubic foot.
Correct, the BTU value per cubic foot varies from municipality to municipality. When I was installing large boilers we had to provide the manufacturer the BTU/ft3 as part of the startup paperwork, along with the final pressure setting on the internal regulators in inches of water column(inH2O). The final pressure was set using a table or equation from the manual and a special gauge.
When I first started I had a U-tube manometer to set the gas regulator pressure. Then I “upgraded” to a magnehelic that my boss gave me when I kept complaining about filling the tube with water (and food coloring if the little bottle hadn’t spilled between jobs!). Had to zero that thing out every time by hanging it level and adjusting it with a little screwdriver. After I racked up some overtime I ended up buying a more expensive differential pressure electronic gauge (fieldpiece SDMN5) which let me do pressure switches for furnaces more easily.
I lost track of how many times I fixed people’s furnaces or tankless water heaters by just setting the gas regulator up right, something most installers skip. Here’s video of the tools and process:
https://youtu.be/D_Jn-m_MvEk
Yep, hence why it kinda smells of farts.
However I am gonna be devil’s advocate for the all caps boomer engineer mailing list. Yeah, he sounds crazy (and is a little) and kind of annoying, but from what I’ve learned in four decades of life is that that guy actually does call it correctly a lot of the time when others get it wrong. Idk what it is about it, but I’ll take him over the professional-sounding guy any day.
Here’s a good example: https://bmwmotorcycletech.info/
Not only that, if you calculate how much gas is in the distribution pipes and gas bells along the way, you’ll find there’s a tremendous amount of energy stored in the system, and it can act as a huge battery if there was only a way to put gas back in the pipes – such as by making hydrogen to methane using wind power.
There’s enough capacity to practically solve the whole energy storage problem, but surprise surprise, the little green men don’t like it at all. No sir, gas and gas appliances have to be banned altogether, otherwise the society might not need to resort to rationing energy through a planned command economy.
So your solution for climate change is to actually build more gas pipelines just to store wind energy in them? I’m not sure the gas companies would be interested.
The trick is, in order to make the average year-round demand out of renewable power, it would routinely produce more instant power than there is grid demand, by a factor of 5-8x and this situation is only going to get worse (less economical) if you try to solve it by simply building more.
Batteries also get terribly expensive and terribly inefficient the longer you plan to store the energy – between months or years – so the only reasonable way to do it would be to store the energy in some sort of simple chemical fuel that you can stockpile and transport easily.
What would that be? Well, hydrogen is the simplest but it’s also the least convenient. Methane comes next. How do you transport methane? Through the gas grid. Where do you store the methane? In the gas grid.
I heard of a farmer who’s working on how to build a tow bar that is 3 months long. So he can save fuel and time to pull the harvester behind the planter.
Maybe I could use the same technology for an extension cord that’s six months long, so I can turn the lights on in the summer when solar power is cheap and enjoy the light in January when it’s dark.
The gas grid could also simultaneously be used to store/distribute hydrogen as well as methane. Not recommending or advocating for that, or hydrogen power in general, but you could do it.
Some kind of separator would be needed for where you needed pure hydrogen (e.g. fuel cells) but regular consumers like boilers and cookers would likely run just fine with hydrogen mixed in.
However I would expect leaks to be a big problem as hydrogen is a smaller and lighter molecule. Hydrogen embrittlement is also something that may present a problem long term.
Solid oxide fuel cells can burn straight up methane and any fuel you can turn into a gas, including carbon. The only thing they don’t like is sulfur.
>…might not need to resort to rationing energy through a planned command economy
I don’t understand why people with such strong anti-communist sentiments are so enamored of monopolistic power grids. If you want to be a government-free, self sufficient individual, why rely on a monopoly that you have no control over (private or public it makes no difference..)?
It seems creating your own micro-grid would more closely align with your political beliefs. If you have a natural gas well on your property, good for you. But for most people it will be more feasible to use solar, wind or bio-fuel in the form of firewood harvested from your own homestead.
Or harvest NG from their biowaste.
IIRC You could run the average economy car with 2 sheep (or one Xlarge HackaDay reader) attached to the fuel system with ‘proper fittings’.
Oversized Foley cath perhaps. Unless you want to hold the sheep or reader still while threads are tapped.
Just what a car culture needs, a gas culture.
It’s not terribly difficult to synthesize gasoline by similar processes as making methane. There’s already some companies looking to build factories that process natural gas into gasoline anyways. It works by converting the gas into ethylene, which can then be made into diesel, gasoline, jet fuel, plastics…
Most mammals come equipped with a built-in compression fitting.
Local distribution is a monopoly. The grid is not. Gas pipeline network is also not.
Even where there is one owner of all transmission into a city/area (e.g. SF bay area), it’s not enforced as a monopoly. It’s just there isn’t enough money in it to justify the huge cost of building a parallel line. Which is why the owner of the single line doesn’t charge everything the market would bear, it would only bring in competition.
You really don’t want to know the gory details of how open access to transmission is administrated. I don’t want to remember that mess. Tagging, Chain of title, chain of ownership, power vs capacity vs load following etc etc etc. All overlaid on top of old long term contracts that are still valid. Power trading is just messy.
You also have to remember that the competition to gas is electric, and competition to electric is gas. As long as consumers have both options, neither can do monopoly pricing anyways.
But as soon as you ban one option, as in California, the other will start to jack up the prices because people have no choice but to use it.
The politicians in California haven’t listened the advice of an engineer for at least 50 years. That’s why their infrastructure is a mess.
In California, the gas and electric companies are generally the same. (For example, the infamous PG&E.) But there is competition to stop them raising prices to whatever they want: solar.
Except solar only “works” because of net metering. It’s not an independent power source – except for those who can afford “powerwalls”.
If you try to compete with conventional power using solar energy the infamous duck curve just keeps getting worse and the power companies will find some other way to charge you for the power that you end up buying from them anyways – such as ridiculously high “service fees” – or they simply raise their hands in defeat and exit the market while the state buys up the generators and starts running the grid as a command economy.
It’s easier to deal with one part of the economy being a natural monopoly and control just that part in a collective manner, than having the entire economy turn into a planned system with the associated corruption and social power issues because you have to dance around artificial limitations that exclude every other working solution to the problem.
Let’s see.. ban nuclear, ban gas, ban ICEs, tear down hydroelectric dams to free the rivers… remove everything that the left/green movement wants to do away with. What’s left over? Very expensive and inconvenient solutions that only the very rich can afford, which necessitates the state subsidizing it for the rest of the people, which means the state taking over the economy – OR – you could let people drive cars and cook with gas, and simply change the supplier of the fuel from fossils to synthetic.
To answer the question itself; back in 2015 the US stockpiles for natural gas reached 3.877 trillion cubic feet, which is worth about 3.9 trillion Megajoules, or roughly 1,000 TWh worth of gas, for the heating value.
The US yearly electricity consumption is around 3,930 TWh, so there’s still some ways to go, but a system that can store and release a quarter of the energy is a good start for providing the kind of resiliency and redundancy needed to operate a completely renewable system through yearly variations and potential disasters, wars, etc. Even as we speak, the strategic reserves for oil and gas span at least three months worth of consumption, and any renewable system should do the same. It’s also possible to import and export gas overseas, so it’s a huge economic opportunity and a second safety factor in case things go wrong.
Meanwhile, the largest grid scale lithium battery in the world is measured in some hundreds of megawatt-hours, which is 10,000,000 times smaller than what we’re talking about. People and governments who are pushing grid energy storage with electric batteries simply do not have any idea – I cannot stress enough how absolutely ignorant they are – they are completely and utterly clueless of the massive scale of the issue, and how little you can actually do about it with any of the “officially sanctioned” ideas and solutions we have.
One reason to consider electric over gas stoves is that there’s a significantly positive correlation between use of gas stoves and development of asthma in children. The effect is bigger yet for traditional wood-burning fireplaces.
(I grew up using electric stoves/ovens to cook and I haaaate trying to cook on gas stoves. All my friends love them, but they frustrate me.)
Also true of all forced air heat/cooling, it stirs up dust.
You’re happier not knowing what typical residential dust is made of. Dead human skin is the least disgusting fraction.
Nobody heats with ‘fireplaces’. Wood burning stoves (including fireplace inserts) aren’t nearly as bad. Fireplaces are for f*&(ing in front of.
Are you going to do a follow-up article about removing hydrogen sulfide (H2S) from natural gas?
My natural gas prices have gone up about 25% (summer rates, nearly 50% for winter rates) over the last year.
But compared on by unit of usable energy, it’s still 1/4th the cost of electricity (even accounting for efficiency losses in my 90+% efficient furnace).
The math suggests Natural gas is cheap enough that if I got a natural gas generator (~40% efficient) and ran that instead of pulling power from the grid, it would pay for it self in just a few years (faster than the solar panels).
In order for electricity to compete with natural gas for operational heating costs you need a 400% efficient geothermal heat pump, and that of course can’t beat natural gas on capital costs.
Basically natural gas is going to be around for a while, until either the prices get driven up to point where alternatives are more appealing, or until alternatives are cheap enough to compete.
Of course the increase of natural gas prices is due to increased demand after shutdown of coal fired power plants.
Instead of or alongside your gas boiler, run your generator, and also use the waste heat to heat water and/or you living spaces. Then it’s suddenly 140% efficient.
Then, use the electricity to power a heat pump – it’s now 540% efficient!
Don’t forget there are adsorption heat pumps that run on gas as well.
I was told a few decades ago that during very cold weather on the northern tier, one third of the natural gas is consumed by the turbines maintaining the pressure in the pipeline.
I know of a large gas fired plant in CA that saved money on it’s electric gas pumps by putting them on a curtailable power contract. Brilliant bean counters that PG&E employed. Was some time ago.
I doubt the 1/3 figure. The CO2 from the turbines stays in the gas line. They use fairly conventional jet engines but only inject a little air and run super rich.
There are many gas appliances (typically the more modern ones) that also require electricity to operate even if they have gas, effectively containing a dead man valve that won’t turn on the gas unless there’s also an AC supply.
So if you’re counting on your kitchen stove to work in the zombie apocalypse, go flip the breaker and test what it does.
Use a match or candle lighted for ignition.
A lot of them won’t start the flow at all. Test it.
We removed ours in the Kitchen remodel, the wife wanted a smooth top.
Burners will light with a match, oven won’t.
Buddy had this happen to him in the Texas freeze. He had to use an inverter to power the main gas solenoid to get it going.
RVs fridges also have this. It is a safety solenoid, normally-closed. Requires power to use the fridge on propane.
For a moment I thought the intro was a setup for a Hank Hill joke, but he was all about that propane…
and propane accessories.
The resilience of the natural gas grid got tested in Texas last winter. It didn’t fare all that well.
What do you mean? The gas companies made record profits at the time, due to a market that pays them more for under-delivering. What matters more than profits?
Upstream gas is not scented.
Last gas leak I was around in a compressor station had no smell or taste. The building is equipped with gas detection, and it is standard practice for workers in the building to carry a personal gas monitor.
It’s not as scary as it sounds – but you do need to understand and respect the hazard.
Mouth felt a bit dry, my monitor showed some gas present but not anywhere close to the lower explosive limit, and I actually found the leak in the packing on the head end of a reciprocating compressor cylinder with my hand – you could feel a small ‘puff’ ‘puff’ from the leak with every stroke.
Yeah, see this is the crazy thing to me.
I just can’t imagine how all these installations work without blowing up all the time.
I know how frustrating it is to find and fix leaks in compressed air systems, and compressed air has fairly limited ability to go “boom” when it gets out of the pipes.
I would imagine that working in a gas facility with thousands of fittings would be like working in a refinery, where dozens of old packing glands and aging joints are slowly dripping out gasoline onto the floor – only you can’t see it or smell it. This is not a mental image that would instill in me a tendency to deep, restful sleep every night.
It’s because the concentration over which explosions can happen is relatively narrow, and it’s difficult to ignite until the concentration increases towards over-rich. It’s difficult to maintain the exact right amount of gas in the air to cause an explosion.
It’s not like hydrogen which goes “bang” from everything and anything – which may become a problem in the future because countries, e.g. Germany, are looking into stuffing hydrogen into the gas lines to substitute NG. They say it can take up to 30% before problems start to crop up, but we’ll see.
In high school chemistry class they “blow stuff up” using super explosive gasses like hydrogen that are flammable from about five to about seventy five percent mixture, so you don’t have to measure, just crack open the tank and it’ll go boom every time. However natgas only burns from five to fifteen percent. Nobody else gave the numbers, these are “engineering rules of thumb” accurate to one sig fig so plz no complaining that its actually 4.325235% according to some authority, “about five” is close enough for safety engineering purposes.
Kind of interesting if you’re a chemist that that the lower limit of pretty much almost everything is a single digit percentage over a 10:1 ratio but the upper limit varies over a wider range from 1 to 100%… Yes there are things that burn at a 100% in air, some weird epoxide plastic/glue precursor IIRC, quite dangerous stuff as I recall.
Also I think you underestimate how much air moves around a compressor. Plenty of heat needs to be removed both the thermodynamic compression heat plus inevitable mechanical friction etc. As long as you blow twenty times as much air as gas leaks, you’ll be fine, so anything short of splitting a pipe wide open is a huge waste of resources over time, but is not dangerous.
” things that burn at a 100% in air” – which by definition cannot contain any air.
In any case, it’s probably got something to do with probabilities where at the lower limits you simply won’t find another molecule to react with, and with most fuels falling into a similar range of energy density they only produce so much heat that could accelerate the reaction.
Two different things:
1. The old compressors were powered by the gas as well, and were huge piston engines. Coolspring power museum in Pennsylvania has a restored one they run when they are open. It’s a whopping 600HP. 86,800 cubic inch displacement.
https://www.youtube.com/watch?v=cZxNzU8SNR4
https://www.youtube.com/watch?v=9fod-ZraaGc
2. The NY state government is committed to eliminating natural gas, propane, oil, and wood heat. They are forcing everyone to electric while shutting down power plants and adding electric cars. The reliability issues are completely ignored. Our electric supply goes out 2-3 time a year, twice in the last 20 years for over two weeks(both in the winter). I have NEVER had the natural gas supply fail.
“I have NEVER had the natural gas supply fail.”
That is why the NY government wants to eliminate it, it is much easier to control people by shutting off their electricity instead of waiting for the NG grid to use up all the gas in the pipelines.
I THINK I KNOW THE GENTLEMAN WHO USES ALL CAPS: Steven Harris, and he is quite the mad genius. He certainly is an energy expert in the petroleum and battery fields. I heard him make the same claim about natural gas based on a conversation he had with a natural gas industry expert. Steven has some interesting and unorthodox thoughts about energy and I recommend you at least give him a listen sometime.
Some gas pipeline compressors are powered by electricity. There was some push in the 1990s to convert from gas power to electric power. I know of one in Kentucky that has three 4000 hp electric motor driven compressors.
Real World Example. Approximately 5 years ago (1997) we had a projected cold snap coming in the South West US. El Paso TX had 2 gasoline refineries one decided to shut down and the other decided to keep running. That second one eventually froze in the cold. As the power gird started to fail, rolling blackouts were instituted. The blackouts in West Texas affected the pumping stations that gathered raw Natural Gas and fed it into the main collection plant. This collectiing plant cleans, blends and puts that natural gas into the main pipeline. Well the main line pressure started to drop and the only choice was to shut done sections that were receiving the gas. It turned out that after schools and other obvious choices large areas were shut down. The city of Ruidoso NM was shut down. Mostly a vacation area so at the time it made sense. People living in the city went to Walmart and bought electric heaters. Houses that were vacant just froze.
Other interesting stories came from this episode. But my conclusion is Nat Gas is only as reliable as the power grid supporting it.
looking at some of these ‘studies’, I can’t tell what the contribution of the actual combustion and what is caused by the actual cooking of foods. In any case, an exhaust fan that vents outside pretty much solves the this issue, if it really exists.
Over the past 50+ years asthma has been increasing in urban populations, where more and more parents want to wrap the children in bubblewrap and keep them inside, safe from all of the boogymen.
Gas is far more efficient and cost far less to operate than electric stoves. In CA, we pay $0.69/kwh. Gas is less than 25% of that cost per Btu.