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Category: STEM (Page 1 of 11)

Science, Technology, Engineering, Medicine

To Support Coal Buy an EV


What? Yes, it’s true. Read on.

This post is intended for my fellow West Virginians. West Virginia is coal country so a lot of West Virginians support the coal industry.

I look at the big picture as an engineer. Now that the pollution problems associated with coal were mostly solved decades ago, I see coal as just another fossil fuel that we burn to obtain energy. It also happens to be what we have an abundance of in West Virginia.

I’ve watched climate change coming since 1990 and it’s going to bring huge difficulties. You ain’t seen nuthin’ yet. The bottom line is humans have to eventually stop burning things to obtain energy. Achieving this goal is going to take a long time. I’m a realist. It’s going to take far longer than we can afford but that’s how it’s going to be. We’ll be burning coal for a long time to come.

However, that doesn’t mean there’s nothing we can do to reduce our CO2 output. In fact, there’s something we can do to reduce CO2, save our hard-earned money, and support the coal industry, all at the same time. Sound impossible? It’s not. I’ll explain why.

Power Plants and Efficiency

To explain this we need to talk a bit about engineering, but this is something anyone can and should understand. It’s not complicated. Engineers who design machines or electronics are always interested in efficiency. In simple terms, efficiency means how much “input stuff” do you have to put into a device or system to get a certain amount of desired “output stuff” and how much is lost along the way.

In the simple case of an electric motor, if you put in 100 watts of electric power and get 75 watts of mechanical power out, the motor is 75 percent efficient. The other 25 percent is wasted/lost as heat. Nothing is ever 100 percent efficient. There are always losses.

If you have two or more devices one after the other (in series), you multiply together the efficiencies of each device to find out what the total system efficiency is. So, taking some typical figures, if we have a gasoline engine that’s 25 percent efficient, followed by a transmission (geartrain) that’s 80 percent efficient, the total efficiency at the output of the transmission is 0.25 times 0.80 equals 0.20 or 20 percent efficiency. The other 80 percent is lost as heat. This principle will become important below.

Power plant technology has improved continuously since the steam engine was invented. Efficiency is, by far, the most important factor in the design. Power plant efficiency means how much of the chemical / thermal energy in the fuel ends up coming out of the plant in the desired form and how much is lost as heat. Early steam engines were horribly inefficient. Only a few percent. Coal-fired power plants built in the 1970s achieve an efficiency of around 35 percent. So 35 percent of the thermal energy in the fuel leaves the plant as electricity. It may not seem like it, but this is pretty impressive. Modern coal plants built in recent years reach 45 percent efficiency and this is probably close to the maximum possible.

As an aside, natural gas power plants can employ designs that are not possible with coal. The most advanced natural gas plants can reach an unbelievable 60 percent efficiency. But, we’re not talking about natural gas here, we’re talking about coal. But I’ll mention this figure once more at the end of the article.

It probably goes without saying but I’ll point it out anyway. The more efficient a power plant is, the less fuel it consumes, but also the less CO2 it produces to generate a given output. This will become important below.

Internal Combustion Engines (ICE)

Now let’s look at internal combustion engine (ICE) cars. The overall efficiency of modern cars ranges from 12 to 28 percent. That’s the system efficiency measured from the energy in the fuel to moving the car down the road. But the 28 percent figure only applies to certain cars under certain conditions. My little Corolla probably gets close to that 28 percent figure when on a flat highway, at a reasonable speed, no headwind, I’ll get 38 mpg. When city driving, that figure drops way down and I get 24 or 25 mpg. Many cars, SUVs, pickups, do much worse. At no time does any ICE powered vehicle reach the efficiency of the oldest coal-fired power plant. Most of the time the coal plant is 2 to 3 times as efficient at turning fuel into usable power.

Ignoring the frictional losses of all the moving parts in an internal combustion engine, a problem it’s had since it was invented is something called the “power curve”. An IC engine produces maximum power at a certain RPM, maximum torque at a different RPM, and maximum efficiency at yet another RPM. At low RPM it produces little power or torque. At idle, it produces no usable output but still consumes fuel.

Electric Motors and Cars

Modern electric vehicles are powered by 3-phase induction motors. Small electric motors achieve 70 or 80 percent efficiency but the efficiency rises rapidly for larger motors. At the 100 horsepower level, such 3-phase motors are more than 95 percent efficient. Larger ones are even more efficient. And that’s running on fixed mains power at a fixed voltage and frequency.

The 3-phase motors in cars are powered by a sophisticated motor controller that varies the voltage and frequency as the motor’s speed and load changes. That gives these motors a flat power curve and even higher efficiency. At low RPM / low speed they produce lots of torque. At high RPM / high speed they produce the horsepower the car needs. The efficiency stays constant at all speeds.

So what’s the system efficiency of an electric car? The lithium batteries used in electric vehicles have a charge/discharge efficiency around 85 percent. So 85 percent of the electricity you put in comes back out to power the car. Fast charging pushes that number down towards 80 percent. Charging slowly at home pushes it up close to 90 percent.

So the motor gives at least 95 percent efficiency, the motor controller is 98 percent efficient, the battery 85 percent, there is no transmission. Multiplying those together we have around 79 percent efficiency from the charger plug to moving the car down the road. I’m ignoring regenerative braking that harvests the energy from braking to charge the battery. No ICE vehicle can do that, harvest the energy from the brakes and convert it into gasoline.

The electrical grid that transports electric power from the power plant to the home or charging station is very efficient. Over the short distances found in West Virginia, it’s nearly 100 percent efficient and can be ignored.

Conclusion

And so we’ll pull all the numbers together here: coal-fired power plant at 35 percent efficiency and 79 percent efficiency in the vehicle means 27 percent system efficiency from coal to moving the vehicle, any vehicle, down the road. All the time, city, or highway. That’s equal to my Corolla under rare perfect conditions. With a more modern coal-fired plant, it’s 36 percent efficient from coal to moving the vehicle down the road. Well beyond what an ICE vehicle can achieve. “Fueling” an EV from coal generates, on average, one-half to one-third the CO2 of burning gasoline or diesel in an internal combustion engine.

What’s more, the cost of that energy is much lower than buying gasoline or diesel. For example, a high-end Tesla Model S with the big battery pack option, completely discharged, at the electric rates we pay in West Virginia, costs about $12.00 to “fill up”. On top of that, your money isn’t going to a company in Texas, Mexico, Venezuela, The Netherlands, Saudi Arabia, or Russia. It stays right here in West Virginia. West Virginia generates about twice as much electricity as it uses locally. The rest is sold to out-of-state utilities. Availability of locally generated power is not a problem.

For those of you not in West Virginia or coal-country, if your electricity comes from hydro, wind, solar, or nuclear, like in the Pacific Northwest, no fuel is burned and no CO2 generated to power an EV. If your power comes from a modern gas-fired plant like in Florida, efficiency is 2 to 4 times that of an ICE vehicle and about one-third the cost.

As soon as I can solve the charging-at-home problem, I’ll be getting an EV and it will have a bumper sticker that says “This Car is Powered by Coal”.

tl;dr version: It’s more efficient, cheaper, and produces less CO2 to “fuel” an EV with coal-generated electricity than an equivalent ICE vehicle burning gasoline or diesel. Roughly twice as efficient and at one quarter the cost.

Our Favorite Things are Aldehydes


Aldehydes and Allergies

Aldehydes are so common and important in our lives that it’s good to know something about them. The flavor of vanilla, almond, cinnamon, and many others result from aldehydes. Aldehydes are a family of chemicals that are common in nature and foods, and important in industry. I knew that artificial vanilla and almond flavorings posed little danger to people with nut allergies. But the question came up in a discussion and I decided to find out if what I knew was, in fact, correct. (It is.) In the process of researching this, I fell down a rabbit hole of fascinating information, learned a number of interesting things related to chemistry and food chemistry, and collected it here in this article.

There is a family of chemicals called aldehydes that are extremely useful to plants and industry. It’s called a “family” because aldehydes have a common core molecular structure with an open bond to which various molecules can be attached that give various effects.

Three common aldehydes

One thing aldehydes have in common is strong and distinctive odors. Another characteristic of aldehydes is that most of them are toxic in sufficient concentration. (Concentration is key here. At low concentrations, most of them are harmless.) I expect you are already familiar with or have heard of several of the aldehydes I’ll mention.

Formaldehyde

The one I’ll mention first is not closely related to foods but is one you’ve almost certainly heard of. Formaldehyde1 is a critically important chemical in many industries including plastics manufacturing, fibers, and adhesives. Some of the best and strongest waterproof glues are based on formaldehyde. Formaldehyde is a disinfectant and is used to preserve biological specimens. In biology class you may have seen specimens or body parts preserved in jars. Those were likely filled with formaldehyde as a preservative. Formaldehyde is toxic2 and carcinogenic in sufficient concentration. It’s produced in small amounts by most organisms, including humans.

You’ve all smelled it. It’s a key ingredient in “new car smell”, “new carpet smell”, and “newly constructed house smell”. Our noses are sensitive to aldehydes so very low concentrations are detectable.

Acetaldehyde

The next one is acetaldehyde.3 This one is produced by plants and occurs in bread, coffee, and ripe or overripe fruit, and is a component in the fragrance of wine and the smell of smoke. Acetaldehyde4 is formed from the oxidation of ethanol. It forms in the bloodstream after drinking alcohol and is partly responsible for hangovers.

⊂•⊃

Plants discovered the value of aldehydes a long time ago. When nature discovers a chemical that provides two unrelated benefits for the price of one, it’s a definite keeper. Aldehydes are such chemicals. Some of the most important flavors in foods result from aldehydes.

Vanilla

Vanillin5 is a member of the benzaldehyde family of aldehydes and is the chemical responsible for the flavor and fragrance of vanilla. It makes the seed pod of the vanilla orchid attractive to birds and animals and is an insecticide. Two functions for the price of one. Unlike most aldehydes, vanillin has low toxicity and is classed as merely an irritant.6

Vanilla has been in use in the Americas for at least 4,000 years. It was brought to Europe by Spanish explorers in the 1500s.

Cinnamaldehyde

The odor and flavor of cinnamon comes from an aldehyde that’s found in the bark of the cinnamon tree and various others where it serves as an insecticide. Cinnamaldehyde7 is a pale viscous liquid that functions as an anti-bacterial, anti-fungal, and is a potent repellent and killer of Aedes mosquitos. Like vanillin, cinnamaldehyde has low toxicity and is classed as merely an irritant.8

At high humidity and temperature, cinnamaldehyde decomposes to styrene. This is why cinnamon always contains a small amount of styrene.

Benzaldehyde9

This is the aldehyde that gives almonds their flavor.

It also occurs in certain fruits and the pits of peaches, apricots, apples, and cherries. It makes the fruit more attractive to animals and is an insecticide. It’s frequently used by bee keepers as a bee repellent. The odor causes bees to leave the hive while honey is collected after which they return to the hive.

Benzaldehyde is the simplest of all the aldehydes consisting of a benzene ring attached to the open bond of the aldehyde molecule. Benzaldehyde is classed as an irritant.10

⊂•⊃

Vanillin, cinnamaldehyde, and benzaldehyde are chemically classed as merely irritants. Technically all three are toxic in sufficient concentration, but so is water. To reach dangerous levels you’d have to consume absurdly large amounts. In the case of almond extract, you’d die of alcohol poisoning long before reaching dangerous levels of benzaldehyde.

The key here is concentration. Human noses are quite sensitive to aldehydes so for flavoring only a tiny amount is needed. Since most kitchens lack the ability to measure microgram quantities, these extracts are heavily diluted with alcohol so useful amounts can be measured with a teaspoon. At levels used for food flavoring there is some evidence these compounds provide anticarcinogenic effects.11

These aldehydes can all be synthesized in the laboratory or made inexpensively at industrial scale. There is no difference between vanillin made by an orchid and chemically produced vanillin. The same is true for benzaldehyde. If anything, the synthetic version gives a purer more consistent flavor note because it’s pure and not complicated by myriad other chemicals that vary from plant to plant.

Cilantro

The flavor of cilantro derives from several substances, some of which are aldehydes. Some people perceive the flavor of cilantro as a refreshing lemony-lime but some perceive it as tasting like soap or something rotten. It was found that 80 percent of identical twins had the same perception of cilantro but only 50 percent of fraternal twins did. This implied a genetic cause. Today the gene(s)12 have been identified. It’s believed that those who like cilantro are unable to detect one or more of the aldehydes in cilantro.

Furfural

Furfural is an aldehyde that results from the dehydration of sugars. It occurs in agricultural by-products like corncobs, oat bran, oat hulls, wheat bran, and sugarcane bagasse. It’s a common ingredient in processed foods and beverages. It commonly appears in many cooked or heated foods.

Furfural13 is classed as acutely toxic, an irritant, and health hazard.14

It’s dangerous to the skin. NIOSH permissible level is 5 ppm. 100 ppm is considered an immediate danger. Furfural is lethal to rats and dogs at concentrations of 200 to 1000 ppm. It’s flammable and explosive when mixed with air. It has a penetrating odor reminiscent of almonds. There is no data on human subjects.

Retinaldehyde

The importance of aldehydes cannot be overstated. Retinaldehyde15 is found in meats and is the chemical basis of our eye’s ability to sense light. Another name for it is Vitamin A aldehyde. Vertebrates acquire it directly from eating meat or can also synthesize it from carotenoids. In higher concentrations it’s classed as an irritant and a health hazard.16

Glycolaldehyde

This aldehyde is believed to play an important role in the formation of the chemical building blocks of life.17

Interestingly, radio astronomy has detected glycolaldehyde in interstellar space. It’s also been identified in Comet Lovejoy, along with ethanol. This aldehyde is classed as an irritant, highly reactive, and is a common metabolite produced by living things ranging from bacteria to humans.

Lily Aldehyde / Lysmeral / Lilial

Lily aldehyde18 has a strong floral odor reminiscent of lily of the valley. Thousands of tons are produced each year for use in perfumes and detergents.

It’s classed as a health hazard,19 found to be harmful to fertility, and is banned in the EU since March 2022.

Citral

If you’ve made it this far in this article, you can probably guess from the name that citral20 is the aldehyde primarily responsible for the fragrance of citrus fruits like lemon, lime, etc.

Citral is found to have a pheromonal effect on acari and insects. Chemically, it’s classified as an irritant.21

It’s a component in the oils of several plants, as follows.

Lemon myrtle (90–98%)
Litsea citrata (90%)
Litsea cubeba (70–85%)
Lemongrass (65–85%)
Lemon tea-tree (70–80%)
Ocimum gratissimum (66.5%)
Lindera citriodora (about 65%)
Calypranthes parriculata (about 62%)
Australian ginger (51-71%)
Petitgrain (36%)
Lemon verbena (30–35%)
Lemon ironbark (26%)
Lemon balm (11%)
Lime (6–9%)
Lemon (2–5%)

Citronellal

Citronellal is the aldehyde that gives citronella its lemony scent. Citronella22 is an insect repellent. Research has shown it to be highly effective at repelling mosquitos and is a strong antifungal.

Chemically, it’s classed as corrosive, an irritant, a health hazard, and environmental hazard.23

Allergies

Lastly, we come to allergies, specifically allergies to benzaldehyde or vanillin. It’s possible for a human to develop an allergy to almost anything, even metals like nickel. The good news is that it’s rare for someone to be allergic to these two aldehydes that are such important flavors.

The vast majority of allergies, whether it’s to pollen, animal dander, fish, shellfish, bee stings, whatever, are allergic reactions to proteins found in those things.

Natural almond extract is made by steaming almonds in a pressurized vat, then extracting the almond oil. This liquid includes not just benzaldehyde but many other chemicals including proteins. These proteins are usually what a person with a nut allergy reacts to. Genuine vanilla also contains many chemicals from the plant besides vanillin.

Artificial almond extract consists of a small amount of synthetic benzaldehyde diluted with ethanol. Neither has been anywhere near an almond tree and it contains no proteins or anything else. The same is true for artificial vanilla.

The concentration is chosen to match the flavoring power of genuine almond or genuine vanilla extract so the artificial is interchangeable with the genuine in recipes.

Fortunately, this means that those with nut allergies are almost sure to be safe with artificial almond or vanilla flavoring. Even so, if you have a nut allergy, especially a bad case, you should check with your doctor / allergist. They will be able to specifically test whether you are allergic to benzaldehyde (unlikely) or to the dozens of other compounds in nuts.

As a final note, a significant number of children and adults test positive for allergy to cilantro but only a few exhibit symptoms. For those who do, the symptoms can be severe.

Coronavirus Covid-19 Quizzes

In the interest of getting more information on the Covid-19 virus out and in easily digested form, I’ve developed three educational quizzes. Those quizzes have been added to my existing quiz web site.

The Covid-19 virus is new and much is being learned. New discoveries are made and our knowledge refined every day. There are changes in what’s known every day. In compiling information for these quizzes, I found many examples where information published a week or two ago is already obsolete. These quizzes are based on the best information I could find as of March 18, 2020.

I will do my best to keep these quizzes up to date. Please comment here on this blog post with any updates or incorrect information you may find. Ideas for additional questions or additional quizzes are welcome. In fact, this blog post exists so that you have a place to leave comments.

Click here to go to the quizzes.

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