Tag Archives: gas

Biden stops fracking and gas prices go up 300% — Surprise!

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Natural gas prices for June 2022 as of May 6, 2022.

Natural gas prices have quadrupled in the last 17 months. It’s gone from $2.07 per million BTU in mid January 2021 when Joe Biden took office, to nearly $9 today. It’s a huge increase in the cost to heat your home, and adds to the cost of any manufactured product you buy. Gasoline prices have risen too, going from $2/gallon when Biden took office to about $4.40 today. Biden blames the war with Russia, but the rise began almost as soon as he took office, and it far outstrips the rise in the price of wheat shown below (wheat is grown in Ukraine — it’s their major export). The likely cause is Biden’s moratorium on fracking, including his decision to stop permitting oil exploration and drilling on federal land. In recent weeks Biden has walked back some of this, to the consternation of the environmentalists. On April 15, 2022, the Interior Department announced this significant change including its first onshore lease sale since the moratorium.

Biden also cancelled the Keystone XL oil pipeline that would have brought tar-sands oil from Canada and North Dakota to Texas for refining. Blocking the pipeline helped increase gas prices here and helped cause a recession in Alberta and North Dakota. The protesters who claimed to speak for the natives are not affected.

Another issue fueling price increases is that Biden is printing money. Bidenflation is running at 8%/year. It’s not hyperinflation, but it’s getting close. It’s money taken from your pocket and from your savings. Much of the money is given to friends: to groups that Biden thinks will use it virtuously, but inflation is money taken from us, from our pockets and savings. Another beneficiary are those who are rich enough to take no salary, but live by borrowing against their real estate and corporate equity. The richest people in the US do this, earning $1 per year or less, (here’s a list compiled by Bloomberg, it’s basically every rich person). They pay no taxes, as they have no income. The only way to tax them is by tariffs, taxing what they import, but the government is against tariffs.

What you can do, personally about energy-cost inflation is not much. I would recommend insulating your home. I plan to repaint the roof white, and put in a layer of roof insulation. I also have fruit trees: an apple tree and a peach tree, grapes and a juneberry. They provide summer shade, and you get a lot of fruit with minimal work. Curtains are a good investment. Another thought is to buy solar cells. A vegetable garden is fun too, but it’s unlikely to pay you back.

Winter wheat prices are up by about 40%, likely due to the loss of supply from Ukraine and Russia

Speaking of wheat prices, they are up. They increased 40% when Russian troops invaded Ukraine, and have held steady at that level since. This is far less increase than for natural gas. Corn and rice prices are up too, but nowhere near as much. Fertilizer prices are up 300%, though, and Biden has indicated he’d like to push for a sustainable alternative; is that poop? There is a baby formula shortage too. We can handle it, I think, unless Biden get involved, or starts a hot war with Russia.

Robert Buxbaum May 10, 2022. As a fun sidelight, here is Biden answering questions about Pakistan when someone in a Bunny costume grabs him and walks him away from the reporters. Who is that masked handler? What’s going on in Pakistan?

Qatar, unbalanced but stable

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Doha Airport, Qatar.

Doha Airport, Qatar.

I visited Qatar twice this month, just passing through and only visited in the airport, but there were several things that so impressed me that I had to write. What impressed me most was not so much the size and richness of the airport, but the clothes of the locals. All of the local men wore the same, very sharp robes: blindingly white, long sleeved, and floor-length. They’re called Thobes. While other nations wear something similar. Here, every one was unwrinkled, and unstained. They all looked new, with no signs they’d ever been washed. Some were worn with cuff-links (gold), and most had a pen sticking out of the breast pocket (gold). White pants peak from underneath and a headress usually sits on the head. It’s a really dramatic look, like seeing dozens of Ricardo Montaubans of Fantasy Island in one place. Local women and children were these too, but I found the thobes so dramatic that the women and children disappeared from my mind-space almost immediately. There is a local woman in the picture above, but you hardly notice.

Not everyone wears the thobes. There are lots of stores filled with gold and technology, beer and coffee, and these are maned by non-locals, Moslems mostly, almost all men. The non-locals wear western garb, not particularly sharp; none wear thobes of any sort. Some months ago, I wrote that China had severe imbalance and speculated that it was ripe for revolution. As it happens the large number of foreign worker means that Qatar is far more unbalanced. To some extent this is shown by the male-female population pyramid below.

Qatar demographic pyramid. Vastly more males than females, mostly foreign workers.

Qatar demographic pyramid. The imbalance is caused by the presence of vastly more male than female foreign workers.

Qatar is a country of 2,500,000 residents, of whom 310,000 are locals — citizens and permanent residents. The rest are foreign workers; long term inhabitants without permanent residency or citizenship. They make up 85% of the population. They are  recruited from poor, English-speaking Muslim countries mostly: Egypt, Malaysia, Tunisia. They do all the work, as best I could tell. I saw no one who looked like a local working, male or female.

Foreign workers have very few rights, but don’t seem unhappy. There is no right to unionize, and not even the right to roam around the country. For the most part, they live in employer-owned housing, and are transported back and forth to work in employer vans. They sign up for year-long contracts, and at the end of the year, they have the choice to re-up or leave. Up a year ago, foreign workers could not become permanent residents. As of last year, the Emir’s order 10 authorized permanent residency status for as many as 100 foreign workers who had sufficient means, had been in Qatar for 10 to 20 years (depending on whether they were born there), had stayed out of trouble, and who otherwise were considered desirable. It’s a step.

I suspect that the foreign workers feel lucky to have good pay, decent hours, and a clean bed. Then again, the workers are recruited for positive outlook. And the ones I saw might have had more rights than most. The airport is part of the Umm Al Houl, free enterprise zone. These are areas of Qatar where westerners and their vices like alcohol are tolerated and welcome.

Qatar natural gas production. Natural gas provides 90% of the country's income as best I can tell.

Qatar natural gas production. Natural gas provides 90% of the country’s income as best I can tell. That’s half the GDP almost, the rest of the GDP is Qataris spending the money

There are three “free enterprise zones” in Qatar; the name for the one near the airport, “Al Houl” interestingly enough means “bird trap”. What’s going on with them, as best I can tell, is diversification. Qatar is the worlds second largest exporter of natural gas, with most going to Europe, and a significant portion to India and China. But the gas will run out eventually. They are trying to supplant this income with tourism, industry and transport: running a major airline, a bustling, air hub, and tourist hotels. The airline is only marginally profitable, and though I didn’t see the hotels, I imagine they are luxurious and marginally profitable too. Saudi Arabia, next door, is trying to diversify the same ways, aiming to control west-east, air-traffic via Emirates air.

The GDP of Qatar is $191 B as of last year at the going exchange, and over $450 B at price parity. That suggests a few things. For one that the Qatari currency is undervalued. It also suggests a per-capita GDP of at least $76,400, or perhaps of $616,000 or higher depending on how you count buying power and foreign workers. This money buys a nice lifestyle, if not republican freedoms.  In terms of government, Qatar is a real monarchy, Emir Hamad bin Khalifa al-Thani’s is an absolute ruler who came to power the traditional way: he overthrew his father. Similar to this, his father, Khalifa al-Thani, came to power by overthrowing his cousin. Supporting the Emir’s rule, there is an Advisory Council. The 35 ministers are mostly relatives, and as in North Korea, it has only advisory power. The Prime Minister and Minister of Foreign Affairs is Sheikh Hamad bin Jasim bin Jabir al-Thani; the Deputy Prime Minister is Abdallah Al-Thani. The Economy and Commerce minister is Fahd Al-Thani, and the Communications and Transport minister is Ahmad Al-Thani. Nasir al-Thani heads Cabinet Affairs; Hamad al-Thani is the Secretary of State, and the Governor of the Central Bank is Abdallah bin Saud al-Thani.

Qatar main mosque. Residents stand out from the foreign workers.

Qatar main mosque. Residents stand out from the foreign workers.

My sense was that Qatar was the Disneyland version of Islam. Life in the Qatari free zones resembled normal Islamic life the way that Main Street of Disneyland resembles an actual main street in the US. Every citizen is well dress and rich without having to work. Western visitors are welcome, and not forced to follow the local customs with vices in their own zones. And the state supports all ecological and left-wing causes except for unionization. It’s anti Israel, pro revolution (elsewhere of course) and virulently against petroleum production in all counties outside of Qatar. Al Jazeera, the Emir’s left-leaning news agency, spreads money and influence world-wide. Left-flavored news is presented with high-quality graphics, and different versions of the news story published in different languages. The Emir acknowledges that Al Jazeera is a money-losing propaganda agency, but as with Disneyland, most people seem happy to live the fiction.

Qatari woman and shop. They blend into the scenery compared to the resplendent men

Qatari woman and shop. They blend into the scenery compared to the resplendent men

The local Qataris seem happy with their lot, as best I can tell. The next world soccer tournament will be held in Qatar, 2022, and Qatari’s are excited, as best I can tell. There is a lot of building going on, some for the world cup, the rest for general tourism and the free enterprise zones. The free enterprise zones may catch on, but there is a cold war going on with Saudi Arabia, and the Saudi’s are doing what they can to pour cold water on the programs. So far Qatar seems to be winning the propaganda war at home and abroad. Its people are happy, it shows a beautiful, progressive face to the west, and it seems to have the majority of the middle east travel. Stable but for how long?

Robert Buxbaum April 15, 2019. As I side note, I just bought a Qatari Thobe.

Getter purifiers versus Membrane purifiers

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There are two main types of purifiers used for gases: getters and membranes. Both can work for you in almost any application, and we make both types at REB Research – for hydrogen purification mostly, but sometimes for other applications. The point of this essay is which one makes more sense for which application. I’ll mostly talk about hydrogen purification, but many of the principles apply generally. The way both methods work is by separating the fast gas from the slower gas. With most getters and most membranes, hydrogen is the fast gas. That is to say, hydrogen usually is the component that goes through the membrane preferentially, and hydrogen is the gas that goes through most getters preferentially. It’s not always the case, but generally.

Scematic of our getter beds for use with inert gasses. There are two chambers; one at high temperature to remove water, nitrogen, methane, CO2, and one at lower temperature the remove H2. The lower temperature bed can be regenerated.

Our getter beds for use with inert gasses have two chambers; one is high temperature to remove water, nitrogen, etc. and one at lower temperature the remove H2. The lower temperature bed can be regenerated.

Consider the problem of removing water and similar impurities from a low-flow stream of helium for a gas chromatograph. You probably want to use a getter because there are not really good membranes that differentiate helium from impurities. And even with hydrogen, at low flow rates the getter system will probably be cheaper. Besides, the purified gas from a getter leaves at the same pressure as it entered. With membranes, the fas gas (hydrogen) leaves at a lower pressure. The pressure difference is what drives membrane extraction. For inert gas drying our getters use vanadium-titanium to absorb most of the impurities, and we offer a second, lower temperature bed to remove hydrogen. For hydrogen purification with a bed, we use vanadium and skip the second bed. Other popular companies use other getters, e.g. drierite or sodium-lead. Whatever the getter, the gas will leave purified until the getter is used up. The advantage of sodium lead is that it gets more of the impurity (Purifies to higher purity). Vanadium-titanium removes not only water, but also oxygen, nitrogen, H2S, chlorine, etc. The problem is that it is more expensive, and it must operate at warm (or hot) temperatures. Also, it does not removed inert gases, like helium or argon from hydrogen; no getter does.

To see why getters can be cheaper than membranes if you don’t purify much gas, or if the gas starts out quite pure, consider a getter bed that contains 50 grams of vanadium-titanium (one mol). This amount of getter will purify 100 mols of fast gas (hydrogen or argon, say) if the fast gas contains 1% water. The same purifier will purify 1000 mols of fast gas with 0.1% impurity. Lets say you plan to use 1 liter per minute of gas at one atmosphere and room temperature, and you start with gas containing 0.1% impurity (3N = 99.9% gas). Since the volume of 100 mols of most gases a these conditions is 2400 liters. Thus, you can expect our purifier to last for 400 hours (two weeks) at this flow rate, or for four years if you start with 99.999% gas (5N). People who use a single gas chromatograph or two, generally find that getter-based purifiers make sense; they typically use only about 0.1 liters/minute, and can thus get 4+ years’ operation even with 4N gas. If you have high flows, e.g. many chromatographs or your gas is less-pure, you’re probably better off with a membrane-based purifier, shown below. That what I’ll discuss next.

Our membrane reactors and most of our hydrogen purifiers operate with pallium-membranes and pressure-outside. Only hydrogen permeates through the palladium membrane.

Our membrane reactors and most of our hydrogen purifiers operate with pallium-membranes and pressure-outside. Only hydrogen permeates through the palladium membrane.

The majority of membrane-based purifiers produced by our company use metallic membranes, usually palladium alloys, and very often (not always) with pressure on the outside. Only hydrogen passes through the membranes. Even with very impure feed gases, these purifiers will output 99.99999+% pure H2 and since the membrane is not used up, they will typically operate forever so long as there is no other issue — power outages can cause problems (we provide solutions to this). The main customers for our metallic membrane purifiers are small laboratories use and light manufacturers. We also manufacture devices that combine a reformer that makes 50% pure hydrogen from methanol + steam where the membranes are incorporated with the reactor — a membrane reformer, and this has significant advantages. There is no equivalent getter-based device, to my knowledge because it would take too much getter to deal with such impure gas.

Metal membranes are impermeable to inert gases like helium and argon too, and this is an advantage for some customers, those who don’t want anything but hydrogen. For other customers, those who want a cheaper solution, or are trying to purify large amounts of helium, we provide polymeric membranes, a lower cost, lower temperature option. Metal membranes are also used with deuterium or tritium, the higher isotopes of hydrogen. The lighter isotopes of hydrogen permeate these membranes faster than the heavier ones for reasons I discuss here.

Robert Buxbaum, August 26, 2018

Al Jazeera, a multi billion-dollar influence buyer

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Given the hand-wringing over the $300,000 spent by Russia to influence the 2016 US election, I thought it worthwhile to point out that Qatar spent roughly 2.5 billion on influence, mostly through Qatar’s news agency, Al Jazeera. Qatar is a Shiite (Shia) Moslem Emirate solely ruled by a Sunni Emir (king). Here’s a joke to help distinguish Sunni from Shia. It is also the 4th largest exporter of natural gas in the world behind Russia, Norway, and Canada. It’s a solid supporter of leftist political causes from anti-climate change to Hamas and Al Qaeda/ ISIS, and it is the host for the FIFA world cup of soccer, 2022. For more about Qatar and the logic of its behavior, see the American Foreign Policy Analysis. Interesting in general, but I’d like to focus on influence buying.

FILE - In this Aug. 20, 2013 file photo, Al Jazeera America editorial newsroom staff prepare for their first broadcast in New York. Shannon High-Bassalik former head of Al Jazeera America’s documentary unit has sued the news network, claiming it is biased against non-Arabs in stories that it produces and how it treats employees. (AP Photo/Bebeto Matthews, File)

Al Jazeera America prepares for its first broadcast from New York, August, 2013. AP Photo/Bebeto Matthews.

The Emir of Qatar is the sole owner of Al Jazeera, a news organization, that he uses as profit-losing, influence machine. It allowed him to support leftist politicians who he believes to be pro-Arab, pro-Muslim Brotherhood, anti-Israel, and anti-American. In Europe he pursues pro-immigration, anti-fracking policies. In conservative, Islamic countries, like Saudi Arabia, Egypt, and Iran, he’s used Al Jazeera to supported free elections to unseat the king, Shah, or military president. Al Jazeera uniformly portrays Qatar and its emir well, helping it get rights to host the FIFA world cup. No other country gets anywhere near such uniform, positive support.

A bit of history: Al Jazeera began operations in Doha, the capital of Qatar in 1996, as an antidote to Saudi Arabia’s arabic-language news outlet, MBC (Mid-East Broadcast Company, now called Al Arabia). By 2003, Al Jazeera was broadcasting in Europe in various EU languages, and had an english language version broadcast out of London, Al Jazeera-English. It is available in the US via cable TV, Channels 100, 200, and 300. In 2013, the Emir of Qatar expanded Al Jazeera directly to the US, paying 1/2 billion dollars for an Emmy-winning, non-profitable, cable news company “Current TV”, partially owned by Al Gore. “Current TV” operated out of San Francisco with a left-leaning, pro-environment message and a modest audience. Their shows include The War Room with Jennifer Granholm (Jennifer is the ex-governor of Michigan), Talking Liberally, The Stephanie Miller Show, and  Viewpoint with Eliot Spitzer. The Emir added a news headquarters in New York and gave it a new name: Al Jazeera America, or AJAM. The old Current TV was retained as AJ+, a video arm. Over the next 5 years the emir spent 2 billion dollars setting up 12 news bureaus in the US with instructions that there was no need for profit, but only for “influence”. It is arguable how much influence he got, but it is clear he didn’t make any profit.

Despite what you might imagine would be the opinions of a petro-monarch, AJAM continues to back Gore’s anti-fracking message. I will speculate this is because he is against US gas because it competes with Qatari gas. AJAM also strongly supports the Muslim Brotherhood, Hamas, and ISIS. Perhaps that’s radical chic (radical sheik?). He’s against any authoritarian ruler that isn’t him.

Trump, his daughter, el Sisi, and the King of Saudi Arabia. No Emir of Qatar.

Trump, his daughter, Ibn-Said (king of Saudi Arabia) and el Sisi, (president of Egypt). Global control with no Emir.

Some notable controversies — I got these from Wikipedia –Ahmed Mansour, a prominent Al Jazeera anchor, is quoted saying that Egyptian president, el-Sisi was “a Jew carrying out an Israeli plot.” Faisal al-Qassim, another Al Jazeera presenter, hosted a segment on whether Syria’s Alawite (Shia) population deserved to be killed en-mass, and in 2014, the channel’s Iraqi affairs editor tweeted approvingly about the Islāmic State killing more than 1,500 air-force cadets in Tikrit, singling out those who were Shia and non-Muslim. Closer to home, they charged a half-dozen athletes with doping, including Peyton Manning, hero of the super bowl. In the end, Shannon High-Bassalik, former head of the documentary unit, also sued claiming bias against non-Arabs in stories and in how it treats employees.

Among Republicans, AJAM became to be known as “The Terror Network”, while they retained some good reputation on left. The Emir bought not only the network, but spent liberally on sympathetic experts, and on academic think tanks. Further, it seems that Al Jazeera writers had no fixed budget or expense limit. The Russians are nowhere near this generous.

In April of 2016, with the world cup coming to Qatar, and American oil reviving, the emir cut AJAM staff by 900 workers. Part of the decision may have been that it looked like he had the 2016 election in the bag. Al Jazeera English remains, still operating out of London, and AJ+, the old Current TV, still operating out of San Francisco. And then Donald Trump was elected 45th US president. AJ / AJ+ was shocked (as was I); and called for protests. Trump, in a publicized meeting with el-Sisi of Egypt (the Jewish Spy), and Salmon al-Saud, (above, 2017) issued a set of 13 demands including that the emir stop to support for Hamas and the Brotherhood, and that he shut Al Jazeera. The emir has not complied, and the world cup is still on for Qatar.

I should mention that the Emir and Putin work together on some things and oppose on others. They both support politicians who oppose oil and gas production while opposing each other on pipeline construction. Qatar backs the pan Arabian pipeline to Turkey, while Russia funds Assad and the PKK (Russia-friendly, Kurdish independents) to block such access. The Emir supports ISS, Hamas, and Turkish Kurds, I suspect, as a way to fight Russia. It’s Byzantine politics in both senses of the word. Given how much Qatar has spent buying influence with Clinton and Gore, I don’t understand why the FBI is so focussed on Trump and Russia.

Robert Buxbaum, May 29, 2018.

Why are glaciers blue

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i recently returned from a cruse trip to Alaska and, as is typical for such, a highlight of the trip was a visit to Alaska’s glaciers, in our case Hubbard Glacier, Glacier bay, and Mendenhall Glacier. All were blue — bright blue, as were the small icebergs that broke off. Glacier blocks only 2 feet across were bright blue like the glaciers themselves.

Hubbard Glacier, Alaska. Note how blue the ice is

Hubbard Glacier, Alaska. My photo. Note how blue the ice is

What made this interesting/ surprising is that I’ve seen ice sculptures that are 5 foot thick or more, and they are not significantly blue. They have a very slight tinge, but are generally more colorless than glass to my ability to tell. I asked the park rangers why the glaciers were blue, but was given no satisfactory answer. The claim was that glacier ice contained small air bubbles that scattered light the same way that air did. Another park ranger claimed that water is blue by nature, so of course the glaciers were too. The “proof” to this was that the sea was blue. Neither of these seem quite true to me, though there seamed some grains of truth. Sea water, I notice, is sort of blue, but isn’t this shade of blue, certainly not in areas that I’ve lived. Instead, sea water is a rather grayish similar to mud and sea-weeds that I’d expect to find on the sea floor. What’s more, if you look through the relatively clear water of a swimming-pool water to the white-tile bottom, you see only a slight shade of blue-green, even at the 9 foot depth where the light you see has passed through 18 feet of water. This is far more water than an iceberg thickness, and the color is nowhere near as pure blue and the intensity nowhere near as strong.

Plymouth, MI Ice sculpture -- the ice is fairly clear, like swimming pool water

Plymouth, MI Ice sculpture — the ice is fairly clear, like swimming pool water

As for the bubble explanation, it doesn’t seem quite right, either. The bubble size would be non-uniform, with many quite large resulting in a mix of scattered colors — an off white– something seen with the sky of mars. Our earth sky is a purer blue, but this is not because of scattering off of ice-crystals, dust or any other small particles, but rather scattering off the air molecules themselves. The clear blue of glaciers, and of overturned icebergs, suggests (to me) a single-size scattering entity, larger than air molecules, but much smaller than the wavelength of visible light. My preferred entity would be a new compound, a clathrate structure compound, that would be formed from air and ice at high pressures.

An overturned ice-burg is remarkably blue: far bluer than an Ice sculpture. I claim clathrates are the reason.

An overturned ice-burg is remarkably blue: far bluer than an Ice sculpture. I claim clathrates are the reason.

Sea-water forms clathrate compounds with natural gas at high pressures found at great depth. My thought is that similar compounds form between ice and one or more components of air (nitrogen, oxygen, or perhaps argon). Though no compounds of this sort have been quite identified, all these gases are reasonably soluble in water so that suggestion isn’t entirely implausible. The clathrates would be spheres, bigger than air molecules and thus should have more scattering power than the original molecules. An uneven distribution would explain the observation that the blue of glaciers is not uniform, but instead has deeper and lighter blue edges and stripes. Perhaps some parts of the glacier were formed at higher pressures one could expect that these would form more clathrate compounds, and thus more blue. One sees the most intense blue in overturned icebergs — the parts that were under the most pressure.

Robert Buxbaum, October 12, 2015. By the way, some of Alaska’s glaciers are growing and others shrinking. The rangers claimed this was the bad effect of global warming: that the shrinking glaciers should be growing and the growing ones shrinking. They also worried that despite Alaska temperatures reaching 40° below reasonably regularly, it was too warm (for whom?). The lowest recorded temperature in Fairbanks was -66°F in 1961.

Most Heat Loss Is Black-Body Radiation

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In a previous post I used statistical mechanics to show how you’d calculate the thermal conductivity of any gas and showed why the insulating power of the best normal insulating materials was usually identical to ambient air. That analysis only considered the motion of molecules and not of photons (black-body radiation) and thus under-predicted heat transfer in most circumstances. Though black body radiation is often ignored in chemical engineering calculations, it is often the major heat transfer mechanism, even at modest temperatures.

One can show from quantum mechanics that the radiative heat transfer between two surfaces of temperature T and To is proportional to the difference of the fourth power of the two temperatures in absolute (Kelvin) scale.

Heat transfer rate = P = A ε σ( T^4 – To^4).

Here, A is the area of the surfaces, σ is the Stefan–Boltzmann constant, ε is the surface emissivity, a number that is 1 for most non-metals and .3 for stainless steel.  For A measured in m2, σ = 5.67×10−8 W m−2 K−4.

Infrared picture of a fellow wearing a black plastic bag on his arm. The bag is nearly transparent to heat radiation, while his eyeglasses are opaque. His hair provides some insulation.

Unlike with conduction, heat transfer does not depend on the distances between the surfaces but only on the temperature and the infra-red (IR) reflectivity. This is different from normal reflectivity as seen in the below infra-red photo of a lightly dressed person standing in a normal room. The fellow has a black plastic bag on his arm, but you can hardly see it here, as it hardly affects heat loss. His clothes, don’t do much either, but his hair and eyeglasses are reasonably effective blocks to radiative heat loss.

As an illustrative example, lets calculate the radiative and conductive heat transfer heat transfer rates of the person in the picture, assuming he has  2 m2 of surface area, an emissivity of 1, and a body and clothes temperature of about 86°F; that is, his skin/clothes temperature is 30°C or 303K in absolute. If this person stands in a room at 71.6°F, 295K, the radiative heat loss is calculated from the equation above: 2 *1* 5.67×10−8 * (8.43×109 -7.57×109) = 97.5 W. This is 23.36 cal/second or 84.1 Cal/hr or 2020 Cal/day; this is nearly the expected basal calorie use of a person this size.

The conductive heat loss is typically much smaller. As discussed previously in my analysis of curtains, the rate is inversely proportional to the heat transfer distance and proportional to the temperature difference. For the fellow in the picture, assuming he’s standing in relatively stagnant air, the heat boundary layer thickness will be about 2 cm (0.02m). Multiplying the thermal conductivity of air, 0.024 W/mK, by the surface area and the temperature difference and dividing by the boundary layer thickness, we find a Wattage of heat loss of 2*.024*(30-22)/.02 = 19.2 W. This is 16.56 Cal/hr, or 397 Cal/day: about 20% of the radiative heat loss, suggesting that some 5/6 of a sedentary person’s heat transfer may be from black body radiation.

We can expect that black-body radiation dominates conduction when looking at heat-shedding losses from hot chemical equipment because this equipment is typically much warmer than a human body. We’ve found, with our hydrogen purifiers for example, that it is critically important to choose a thermal insulation that is opaque or reflective to black body radiation. We use an infra-red opaque ceramic wrapped with aluminum foil to provide more insulation to a hot pipe than many inches of ceramic could. Aluminum has a far lower emissivity than the nonreflective surfaces of ceramic, and gold has an even lower emissivity at most temperatures.

Many popular insulation materials are not black-body opaque, and most hot surfaces are not reflectively coated. Because of this, you can find that the heat loss rate goes up as you add too much insulation. After a point, the extra insulation increases the surface area for radiation while barely reducing the surface temperature; it starts to act like a heat fin. While the space-shuttle tiles are fairly mediocre in terms of conduction, they are excellent in terms of black-body radiation.

There are applications where you want to increase heat transfer without having to resort to direct contact with corrosive chemicals or heat-transfer fluids. Often black body radiation can be used. As an example, heat transfers quite well from a cartridge heater or band heater to a piece of equipment even if they do not fit particularly tightly, especially if the outer surfaces are coated with black oxide. Black body radiation works well with stainless steel and most liquids, but most gases are nearly transparent to black body radiation. For heat transfer to most gases, it’s usually necessary to make use of turbulence or better yet, chaos.

Robert Buxbaum

Heat conduction in insulating blankets, aerogels, space shuttle tiles, etc.

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A lot about heat conduction in insulating blankets can be explained by the ordinary motion of gas molecules. That’s because the thermal conductivity of air (or any likely gas) is much lower than that of glass, alumina, or any likely solid material used for the structure of the blanket. At any temperature, the average kinetic energy of an air molecule is 1/2kT in any direction, or 3/2kT altogether; where k is Boltzman’s constant, and T is absolute temperature, °K. Since kinetic energy equals 1/2 mv2, you find that the average velocity in the x direction must be v = √kT/m = √RT/M. Here m is the mass of the gas molecule in kg, M is the molecular weight also in kg (0.029 kg/mol for air), R is the gas constant 8.29J/mol°C, and v is the molecular velocity in the x direction, in meters/sec. From this equation, you will find that v is quite large under normal circumstances, about 290 m/s (650 mph) for air molecules at ordinary temperatures of 22°C or 295 K. That is, air molecules travel in any fixed direction at roughly the speed of sound, Mach 1 (the average speed including all directions is about √3 as fast, or about 1130 mph).

The distance a molecule will go before hitting another one is a function of the cross-sectional areas of the molecules and their densities in space. Dividing the volume of a mol of gas, 0.0224 m3/mol at “normal conditions” by the number of molecules in the mol (6.02 x10^23) gives an effective volume per molecule at this normal condition: .0224 m3/6.0210^23 = 3.72 x10^-26 m3/molecule at normal temperatures and pressures. Dividing this volume by the molecular cross-section area for collisions (about 1.6 x 10^-19 m2 for air based on an effective diameter of 4.5 Angstroms) gives a free-motion distance of about 0.23×10^-6 m or 0.23µ for air molecules at standard conditions. This distance is small, to be sure, but it is 1000 times the molecular diameter, more or less, and as a result air behaves nearly as an “ideal gas”, one composed of point masses under normal conditions (and most conditions you run into). The distance the molecule travels to or from a given surface will be smaller, 1/√3 of this on average, or about 1.35×10^-7m. This distance will be important when we come to estimate heat transfer rates at the end of this post.

 

Molecular motion of an air molecule (oxygen or nitrogen) as part of heat transfer process; this shows how some of the dimensions work.

Molecular motion of an air molecule (oxygen or nitrogen) as part of heat transfer process; this shows how some of the dimensions work.

The number of molecules hitting per square meter per second is most easily calculated from the transfer of momentum. The pressure at the surface equals the rate of change of momentum of the molecules bouncing off. At atmospheric pressure 103,000 Pa = 103,000 Newtons/m2, the number of molecules bouncing off per second is half this pressure divided by the mass of each molecule times the velocity in the surface direction. The contact rate is thus found to be (1/2) x 103,000 Pa x 6.02^23 molecule/mol /(290 m/s. x .029 kg/mol) = 36,900 x 10^23 molecules/m2sec.

The thermal conductivity is merely this number times the heat capacity transfer per molecule times the distance of the transfer. I will now calculate the heat capacity per molecule from statistical mechanics because I’m used to doing things this way; other people might look up the heat capacity per mol and divide by 6.02 x10^23: For any gas, the heat capacity that derives from kinetic energy is k/2 per molecule in each direction, as mentioned above. Combining the three directions, that’s 3k/2. Air molecules look like dumbbells, though, so they have two rotations that contribute another k/2 of heat capacity each, and they have a vibration that contributes k. We begin with an approximate value for k = 2 cal/mol of molecules per °C; it’s actually 1.987 but I round up to include some electronic effects. Based on this, we calculate the heat capacity of air to be 7 cal/mol°C at constant volume or 1.16 x10^-23 cal/molecule°C. The amount of energy that can transfer to the hot (or cold) wall is this heat capacity times the temperature difference that molecules carry between the wall and their first collision with other gases. The temperature difference carried by air molecules at standard conditions is only 1.35 x10-7 times the temperature difference per meter because the molecules only go that far before colliding with another molecule (remember, I said this number would be important). The thermal conductivity for stagnant air per meter is thus calculated by multiplying the number of molecules times that hit per m2 per second, the distance the molecule travels in meters, and the effective heat capacity per molecule. This would be 36,900 x 10^23  molecules/m2sec x 1.35 x10-7m x 1.16 x10^-23 cal/molecule°C = 0.00578 cal/ms°C or .0241 W/m°C. This value is (pretty exactly) the thermal conductivity of dry air that you find by experiment.

I did all that math, though I already knew the thermal conductivity of air from experiment for a few reasons: to show off the sort of stuff you can do with simple statistical mechanics; to build up skills in case I ever need to know the thermal conductivity of deuterium or iodine gas, or mixtures; and finally, to be able to understand the effects of pressure, temperature and (mainly insulator) geometry — something I might need to design a piece of equipment with, for example, lower thermal heat losses. I find, from my calculation that we should not expect much change in thermal conductivity with gas pressure at near normal conditions; to first order, changes in pressure will change the distance the molecule travels to exactly the same extent that it changes the number of molecules that hit the surface per second. At very low pressures or very small distances, lower pressures will translate to lower conductivity, but for normal-ish pressures and geometries, changes in gas pressure should not affect thermal conductivity — and does not.

I’d predict that temperature would have a larger effect on thermal conductivity, but still not an order-of magnitude large effect. Increasing the temperature increases the distance between collisions in proportion to the absolute temperature, but decreases the number of collisions by the square-root of T since the molecules move faster at high temperature. As a result, increasing T has a √T positive effect on thermal conductivity.

Because neither temperature nor pressure has much effect, you might expect that the thermal conductivity of all air-filed insulating blankets at all normal-ish conditions is more-or-less that of standing air (air without circulation). That is what you find, for the most part; the same 0.024 W/m°C thermal conductivity with standing air, with high-tech, NASA fiber blankets on the space shuttle and with the cheapest styrofoam cups. Wool felt has a thermal conductivity of 0.042 W/m°C, about twice that of air, a not-surprising result given that wool felt is about 1/2 wool and 1/2 air.

Now we can start to understand the most recent class of insulating blankets, those with very fine fibers, or thin layers of fiber (or aluminum or gold). When these are separated by less than 0.2µ you finally decrease the thermal conductivity at room temperature below that for air. These layers decrease the distance traveled between gas collisions, but still leave the same number of collisions with the hot or cold wall; as a result, the smaller the gap below .2µ the lower the thermal conductivity. This happens in aerogels and some space blankets that have very small silica fibers, less than .1µ apart (<100 nm). Aerogels can have much lower thermal conductivities than 0.024 W/m°C, even when filled with air at standard conditions.

In outer space you get lower thermal conductivity without high-tech aerogels because the free path is very long. At these pressures virtually every molecule hits a fiber before it hits another molecule; for even a rough blanket with distant fibers, the fibers bleak up the path of the molecules significantly. Thus, the fibers of the space shuttle (about 10 µ apart) provide far lower thermal conductivity in outer space than on earth. You can get the same benefit in the lab if you put a high vacuum of say 10^-7 atm between glass walls that are 9 mm apart. Without the walls, the air molecules could travel 1.3 µ/10^-7 = 13m before colliding with each other. Since the walls of a typical Dewar are about 0.009 m apart (9 mm) the heat conduction of the Dewar is thus 1/150 (0.7%) as high as for a normal air layer 9mm thick; there is no thermal conductivity of Dewar flasks and vacuum bottles as such, since the amount of heat conducted is independent of gap-distance. Pretty spiffy. I use this knowledge to help with the thermal insulation of some of our hydrogen generators and hydrogen purifiers.

There is another effect that I should mention: black body heat transfer. In many cases black body radiation dominates: it is the reason the tiles are white (or black) and not clear; it is the reason Dewar flasks are mirrored (a mirrored surface provides less black body heat transfer). This post is already too long to do black body radiation justice here, but treat it in more detail in another post.

RE. Buxbaum

What is the best hydrogen storage medium?

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Answering best questions is always tricky since best depends on situation, but I’ll cover some hydrogen storage options here, and I’ll try to explain where our product options (cylinder gas purifiers and methanol-water reformers) fit in.

The most common laboratory option for hydrogen storage is inside a tank; typically this tank is made of steel, but it can be made of aluminum, fiberglass or carbon fiber. Tanks are the most convenient source for small volume users since they are instantly ready for delivery at any pressure up to the storage pressure; typically that’s 2000 psi (135 atm) though 10,000 (1350 atm) is available by special order. The maximum practical density for this storage is about 50 g/liter, but this density ignores the weight of the tank. The tank adds a factor of 20 or to the weight, making tanks a less-favored option for mobile users. Tanks also add significantly to the cost. They also tend to add impurities to the gas, and there’s a safety issue too: tanks sometimes fall over, and compressed gas can explode. For small-volume, non-mobile users, one can address safety by chaining up ones tank and adding a metal membrane hydrogen purifier; This is one of our main products.

Another approach is liquid hydrogen; The density of liquid hydrogen is higher than of gas, about 68 g/liter, and you don’t need as a tank that’s a big or heavy. One problem is that you have to keep the liquid quite cold, about 25 K. There are evaporative losses too, and if the vent should freeze shut you will get a massive explosion. This is the storage method preferred by large users, like NASA.

Moving on to metal hydrides. These are heavy and rather expensive but they are safer than the two previous options. To extract hydrogen from a metal hydride bed the entire hydride bed has to be heated, and this adds complexity. To refill the bed, it generally has to be cooled, and this too adds complexity. Generally, you need a source of moderately high pressure, clean, dry hydrogen to recharge a bed. You can get this from either an electrolysis generator, with a metal membrane hydrogen purifier, or by generating the hydrogen from methanol using one of our membrane reactor hydrogen generators.

Borohydrides are similar to metal hydrides, but they can flow. Sorry to say, they are more expensive than normal metal hydrides and they can not be regenerated.They are ideal for some military use

And now finally, chemical materials: water, methanol, and ammonia. Chemical compounds are a lot cheaper than metal hydrides or metal borohydrides, and tend to be far more readily available and transportable being much lighter in weight. Water and/or methanol contains 110 gm of H2/liter;  ammonia contains 120 gms/liter, and the tanks are far lighter and cheaper too. Polyethylene jugs weighing a few ounces suffices to transport gallon quantities of water or methanol and, while not quite as light, relatively cheap metallic containers suffice to hold and transport ammonia.

The optimum choice of chemical storage varies with application and customer need. Water is the safest option, but it can freeze in the cold, and it does not contain its own chemical energy. The energy to split the water has to come externally, typically from electricity via electrolysis. This makes water impractical for mobile applications. Also, the hydrogen generated from water electrolysis tends to be impure, a problem for hydrogen that is intended for storage or chemical manufacture. Still, there is a big advantage to forming hydrogen from something that is completely non-toxic, non-flammable, and readily available, and water definitely has a place among the production options.

Methanol contains its own chemical energy, so hydrogen can be generated by heating alone (with a catalyst), but it is toxic to drink and it is flammable. I’ve found a  my unique way of making hydrogen from methanol-water using  a membrane reactor. Go to my site for sales and other essays.

Finally, ammonia provides it’s own chemical energy like methanol, and is flammable, like methanol; we can convert it to hydrogen with our membrane reactors like we can methanol, but ammonia is far more toxic than methanol, possessing the power to kill with both its vapors and in liquid form. We’ve made ammonia reformers, but prefer methanol.