I had an evil thought just now as I attempt to write 2 reports simultaneously. Why do we keep using that superscripted circle in front of C (i.e., ºC) that designates “degree”?
What the hell? We don’t use it for the Kelvin temperature scale. And, who knows if the engineers use it for Rankine? The thing is useless like an appendix or a titular chairman. Get rid of it!
What do you think?
Today I found myself peering at the lovely lavender glow of opaque argon plasma through the viewing screen of a gleaming new instrument. The light-emitting 8000 K plasma sits apparently still alongside the conical metal skimmer. Somewhere a Dewar was quietly releasing a stream of argon into a steel tube that was bent in crisp military angles into and through walls and across the busy spaces above the suspended ceiling. Another cylinder quietly blows a faint draught of helium into the collision cell. A chiller courses cooled water through the zones heated by the quiet but savage plasma. Inside a turbo pump labors to rush the sparse gases out of the mass analyzer and into the inlet of the rough pump and up the exhaust stack.
Up on the roof, the heavy and invisible argon spills along the cobbles of roofing stones until it rolls off the roof onto the ground where the rabbits scamper and prairie dogs yap. The helium atoms begin their random walk into space. The argon shuffles anonymously into the breeze and becomes part of the weather.
All of the delicate arrangements; all of the contrivances and computer controls in place to tune and play this 21st century marvel. And a wonderment it is. The ICPMS obliterates solutes into a plasma state and then taps a miniscule stream of the heavy incandescent argon breath that trickles into the vacuous electronic salsa dance hall of the quadrapole. All the heat and rhythm for the sake of screening and counting atomic ions. What a exotic artifact of anthropology it is. And it all began in a rift zone in Africa millions of years ago.
I just had a conversation with a colleague who is somewhat mainstream in his/her thinking. The question came up as to why can’t we be energy independent. What is taking so long with the electric cars and natural gas powered … everything? When can we break away from middle eastern petroleum?
In the public sphere, all I hear are the questioners seeking reassurance that there are energy forms out there that will allow us to maintain our current level of consumption. They rarely put it exactly that way, but that is the heart of the issue.
I think multiple generations of people have failed to appreciate the natural wonder of liquid hydrocarbons. The C7-C10 fractions of petroleum, whether directly from the ground or from a cat cracker or reformer, are the motive basis for most of our ground transportation. These liquid hydrocarbons are of a reasonably low vapor pressure and high enough boiling point to allow their use in everything from go-carts and lawn mowers to automobiles and caterpillars. Teenagers and grandmothers can pump hydrocarbons into an inexpensive and simple tank for use at ambient pressure and temperature. This liquid has a melting point low enough to make it flowable under nearly all earthly conditions.
The high energy density and the liquid state of gasoline is what makes it nearly perfect for propulsion. The energy density of gasoline is 34.8 mega-Joules per liter (MJ/L), as opposed to 21.2 MJ/L for ethanol.
Yeah, gasoline is cheaper per liter than the bottled water inside the convenience store. That perversion is just a temporary historical aberration. This will change.
Cosmically, hydrocarbons in the C7-C10 range suitable for automotive use are quite scarce in the local stellar neighborhood. Some small hydrocarbon molecules like methane have been spotted in the gas giant planets and on Titan. But for the most part, the only supply of hydrocarbons we have are found in porous deposits below the surface of the only place we can get to- Earth.
We should appreciate our hydrocarbon resources for the true natural wonder that it is and be a bit more reluctant to squander it. I doubt we’ll ever find a source of energy that is as cheap and convenient to use with such a high energy density. Battery technology may get close, but innovation there is a highly specialized art that is beyond the scope of most shade tree mechanics. Common lead acid batteries require material and energy inputs, like everything else, and have somewhat low energy density and a high weight penalty.
Lithium batteries, with their higher energy density require a variety of manufactured and relatively exotic substances. And, they require lithium which is fairly scarce, both cosmically and on earth. We really should be recycling lithium scrap. Seriously, we need to have great respect and appreciation for lithium as well. There really isn’t enough lithium to support everyone’s high energy density lifestyle.
Best of luck to Dale who leaves McMurdo Station tomorrow for the Amundson-Scott Station. Second year in a row that a friend is off to the south pole. He is delivering a detector array for a radio telescope.
C&EN recently published an article on the favorite reactions of several bloggers. It was the result of an open call for favorite reactions by the C&EN blog in celebration of IYC. Naturally, I missed this call for submissions.
I would’ve offered the biosynthesis of squalene oxide and cyclization to lanosterol as my favorite reaction. The domino assembly of phosphorylated terpenoid precursors and the penultimate cyclization with the hydride and methide migrations is a thing of beauty. To make a fused hydrocarbon ring system in aqueous media as complex as the steroid nucleus with all of the stereocenters landing in place as they do is a true wonder of nature!
My working life has been extremely stressful for as long as I can remember. A mirthess steampunk factory of angst and unworkable puzzles against a backdrop of uncollegial passive-aggression. But like most sciency mid-career people, I wear golden handcuffs that hold me back from making a clean break. After years of manning the bilge pumps to keep the place working at maximum capacity, people get tired and inflexible. Minor infractions of protocol project to large images of disrespect and imagined malfeasances that burn into the internal viewing screen of our minds.
I write this blog in part as a means of passing along things I’ve gleaned over time from circumstances and people. Today I have peers who are VP’s of research at some major corporations. Because of the sort of place I chose to align with, my progress will not keep up with these friends. This is the result of the deal I made with the devil years ago. That deal was the result of chosing a location over an organization. The folly of this is now only too apparent and must serve as an example to be passed along.
It is ever so important to be choosy about with whom you sign on and even more important, who you choose to spend your best years with. It is easily possible to commit to corporate beings who demand 110 %, but fail to reciprocate the dedication. Power is in the ability to commit resources. In the business world all manner of things, brilliant or outrageous, are justified by the intonement of the words “business is business”. In the minds of many, this mantra justifies all.
I’m always amazed at how easy it is to don the corporate armor and strut around like a peacock. I did a bit of it myself for a short period after I became a sales manager. But after a month reality threw a bucket of cold water on that fantasy when I realized that power is truly in the hands of people who sign the checks. It always has been. Sales people are a particular breed selected from the herd at large for their goal oriented drive and constant urge to prove themselves.
The chemical business is conservative and socially constipated for the most part. It is nothing like the Silicon Valley paradigm where production is presented as a form of play time. I’m sure it really isn’t, but it is a great recruitment meme.
In business, there are wagon drivers and there are scouts. I’ve come to realize that I am a scout. I love riding into the brush looking for a path. Others are better adapted at coaxing the oxen to pull the wagons.
Business isn’t quite the meritocracy that it is often projected to be. Business demands the adoption of certain kinds of behaviors around the alpha dogs. People land in positions of leadership for all kinds of reasons and sometimes under the most unlikely circumstances. Helpful attributes include singlemindedness, focus on the bare essentials of moneymaking, an engaging personality, and a knack for landing on your feet. Aggressive behavior and a bit of psychopathic ambition are helpful.
The fact of power is the act of power. People early in their careers should strive to understand how power is accumulated and used. Even if you are disinclined to swing the stick around, it helps to understand it.
Get your resumes out and polish ’em up. NASA is lookin’ fer Astronauts. And while you’re at it, take some time to polish up that laconic, aw shucks, Stanford PhD’d toothy grin of yours ’cause it’s show time! Tell ’em about how you’d like nothing more than to strap a solid fuel booster to your ass and light that candle.
Trouble is, we don’t have any hardware to fly. No matter. Just tell ’em Летите я к луне!
The undersea volcano, El Hierro, in the Canary Islands has been in an eruptive phase since October 2011. The volcano is thought to vent approximately 70 meters below the surface. Surface events vary from jacuzzi-like roiling of turbid water to vigorous upwelling rising many meters above the ocean surface.
The blog Eruptions over on Wired is keeping close tabs on this event as it unwinds.
It is worth pointing out that a volcanic occurrence like this, in addition to land-form building, can also be viewed as a geochemical event. Subsurface eruption of magma comprises the extrusion of fluid rock as well as the injection of gases and solubles into seawater. In the process, water is flashed to steam which adds momentum to the upward convection of the water column from the eruption zone. This causes mixing to occur, tempering the water temperature and dispersing dissolved materials into the currents.
What should you do if a raw material for a process is explosive? Good question. Just because a material has explosive properties does not automatically disqualify it for use. To use it safely you must accumulate some information on the type and magnitude of stimulus that is required to give a hazardous release of energy.
But first, some comments on the release of hazardous energy. Hazardous energy is that energy which, if released in an uncontrolled way, can result in harm to people or equipment. This energy may be stored in the form of mechanical strain of the sort found in a compressed spring, a tank of compressed gas, the unstable chemical bonds of an explosive material, or as an explosive mixture of air and fuel. A good old fashioned pool fire is a release of hazardous energy as well. The radiant energy from a pool fire can easily and rapidly accelerate past the ignition point of nearby materials.
Accumulating and applying energy in large quantities is common and actually necessary in many essential activities. In chemical processing, heat energy may be applied to chemical reactions. Commonly, heat is also released from chemical reactions at some level ranging from minimal to large. The rate of heat evolution in common chemical condensation or metathesis reactions can be simply and reliably managed by controlling the rate of addition of reactants where two reactants are necessary.
There are explosive materials and there are explosive conditions. If one places the components of the fire triangle into a confined space, what may have been conditions for simple flammability in open air are now the components for an explosion. Heat and increasing pressure will apply PV work to the containment. In confinement, the initiation of combustion may accelerate to deflagration or detonation. The outcome will minimally be an overpressure with containment failure. If the contents are capable of accelerating from deflagration to detonation, then loss of containment may involve catastrophic failure of mechanical components.
Rate control of substances that autodecompose or otherwise break into multiple fragments is a bit more tricky. This is the reaction realm of explosives. The energy output is governed by the mathematics of first order kinetics, at least to some level of approximation. In first order kinetics, the rate of reaction depends on both the rate constant and the intitial concentration of one reactant. Regarding the control of reactions that are approximately first order in nature, some thought should be given to limiting the reaction mass size to that which is controllable with available reactor utilities. A determination of the adiabatic ΔT will give information that will tell you if the reaction will self-heat past the bp of your solvent system.
There is a particular type of explosive behavior called detonation. Detonation is a variety of explosive behavior that is characterized by the generation and propagation of a high velocity shock through a material. A shock is a high velocity compression wave which begins at the point of initiation and propagates throughout the bulk mass. Because it is a wave, it can be manipulated somewhat. This is the basis for explosive lensing and shaped charges.
Detonable materials may be subject to geometry constraints that limit the propagation of the shock. A cylinder of explosive material may or may not propagate a detonation wave depending on the diameter. Some materials are relatively insensitive to the shape and thickness. A film of nitroglycerin will easily propagate as will a slender filling of PETN in detcord. But these compounds are for munitions makers, not custom or fine chemical manufacturers. The point is that explosability and detonability is rather more complex than you might realize. Therefore, it is important to do a variety of tests on a material suspected of explosability.
A characteristic of high order explosives is the ability to propagate a shock across the bulk of the explosive material. However, this ability may depend upon the geometry of the material, the shock velocity, and the purity of the explosive itself. There are other parameters as well. Marginally detonable materials may lose critical energy if the shape of the charge provides enough surface area for loss of energy. The point is that “explosion” and “detonation” are not quite synonymous, and care must be exercised in their use. The word “detonation” confers attributes that are unique to that phenomenon.
Explosive substances have functional groups that are the locus of their explosibility. A functional group related to the onset of explosive behavior, called an explosiphore (or explosaphore), is needed to give a molecule explosability beyond the fuel-air variety. Obvious explosiphores include azide, nitro, nitroesters, nitrate salts, perchlorates, fulminates, diazo compounds, peroxides, picrates and styphnates, and hydrazine moieties. Other explosiphores include hydroxylamino. HOBt, a triazole analog of hydroxyamine, hydroxybenzotriazole, has injured people, destroyed reactors and caused serious damage to facilities. Hydroxylamine has been the source of a few plant explosions as well. It is possible to run a process for years and never cross the line to runaway.
Let’s go back to the original question of this essay. What do you do if you find that a raw material or a product is explosive? The first thing to do is collect all available information on the properties of the substance. In a business organization, upper management must be engaged immediately since the handling of such materials involves the assumption of risk profiles beyond that expected.
At this point, an evaluation must be made in relation to the value of the product in your business model vs the magnitude of the risk. Dow’s Fire and Explosion Index is one place to start. This methodology attempts to quantify and weight the risks of a particular scenario. A range of numbers are possible and a ranking of risk magnitude can be obtained therein. It is then possible to compare the risk ranking to a risk policy schedule generated beforehand by management. The intent is to quantify the risk against a scale already settled upon for easier decision making.
But even before such a risk ranking can be made, it is necessary to understand the type and magnitude of stimulus needed to elicit a release of hazardous energy. A good place to start is with a DSC thermogram and a TGA profile. These are easy and relatively inexpensive. A DSC thermogram will indicate onset temperature and energy release data as a first pass. Low onset temperature and high energy release is least desirable. High onset temperature and low exothermocity is most desirable.
What is more difficult to come to a decision point on is the scenario where there is relatively high temperature onset and high exothermicity. Inevitably, the argument will be made that operating temperatures will be far below the onset temp and that a hazardous condition may be avoided by simply putting controls on processing temperatures. While there is some truth to this, here is where we find that simple DSC data is inadequate for validating safe operating conditions.
Onset temperatures are not inherent physical properties. Onset temperatures are kinetic epiphenomena that are dependent on sample quality, the Cp of both the the sample and the crucible, and the rate of temperature rise. What is needed once an indication of high energy release is indicated by the DSC is a determination of time to maximum rate (TMS) determination. While this can be done with special techniques in the DSC (i.e., AKTS). TMR data may be calculated from 4 DSC scans at different rates, or it may be determined from Accelerated Rate Calorimetry, or ARC testing. Arc testing gives time, temp, and pressure profiles that DSC cannot give and in my mind, is the more information-rich choice of the two approaches. ARC also gives an indication of non-classical liquid/vapour behavior that is useful. ARC testing can indicate the generation of non-condensable gases in the decomposition profile which is good to know.
Other tests that indicate sensitivity to stimulus is the standard test protocol for DOT classification. Several companies do this testing and rating. There are levels of testing applied based on the result of what the lower series tests show. Series 1 and 2 are minimally what can be done to flesh out the effects of basic stimuli. What you get from the results of Series 1, 2, and 3 are a general indication of explosabilty and detonability, as well as sensitivity to impact and friction. In addition, tests for sensitivity to electric discharge and dust explosability should be performed as well.
The Gap test, Konen test, and time-pressure test will give a good picture of the ability to detonate, and whether or not any explosability requires confinement. The Konen test indicates whether or not extreme heating can cause decomposition to accelerate into an explosion sufficient to fragment a container with a hole in it.
BOM or BAM impact testing will indicate sensitivity to impact stimulus. Friction testing gives threshold data for friction sensitivity.
ESD sensitivity testing gives threshold data for visible effects of static discharge on the test material. Positive results include discoloration, smoking, flame, explosive report, etc.
Once the data is in hand, it is necessary to sift through it and make some determinations. There is rarely a clear line on the ground to indicate what to do. The real question for the company is whether or not the risk processing with the material is worth the reward. Everyone will have an opinion.
The key activity is to consider where in the process an unsafe stimulus may be applied to the material. If it is thermally sensitive in the range of heating utilities, then layers of protection guarding against overheating must be put in place. Layers of protection should include multiple engineering and administrative layers. Every layer is like a piece of Swiss cheese. The idea is to prevent the holes in the cheese from aligning.
If the material is impact or friction sensitive, then measures to guard against these stimuli must be put in place. For solids handling, this can be problematic. It might be that preparing the material as a solution is needed for minimum solids handling.
If the material is detonable, then all forms of stimulus must be guarded against unless you have specific knowledge that indicates otherwise. Furthermore, a safety study on storage should be performed. Segregation of explosable or detonable materials in storage will work towards decoupling of energy transfer during an incident. By segregating such materials, it is possible to minimize the adverse effects of fire and explosion to the rest of the facility.
With explosive materials, electrostatic safety is very important. All solids handling of explosable solids should involve provisions for suppression of static energy. A discharge of static energy in bulk solid material is a good way to initiate runaway decomposition in an energetic material. This is how a material with a high decomposition temperature by DSC can find sufficient stimulus for an explosion.
Safe practices involving energetic materials require an understanding the cause and effect of stimulus on the materials themselves. This is of necessity a data and knowledge driven activity. Along with ESD energy, handwaving arguments should also be suppressed.
A friend from western Pennsylvania was showing me photos from a recent trip to his native land. He was stunned at the extent to which natural gas infrastructure was creeping into the countryside. Former neighbors and distant cash poor/land rich family members were cashing in the family sod for piles of lucre offered by the gas barons. All aboard the good ship Marcellus. And if you missed that boat, the USS Utica is right behind it.
So,some of the eastern states are full of gas? It makes one wonder if the gas holds much helium? Helium is very important as most readers of this blog will know. Helium’s low boiling point makes for a useful low temperature thermostat bath for superconductors. Helium sits within nested Dewars in NMR cryostats, quietly bubbling into the atmosphere, where it begins its random walk to the cold vacuum of space. In exchange for tipping protons in the rotating frame, we send helium atoms back into the cosmos.
Helium supplies were interrupted recently with the maintenance shutdown of a plant in Wyoming. This square western state also blows gas. Tremendous amounts of it. The sweetening process for all of this gas produces massive amounts of sulfur byproduct.
It is not uncommon for Th’ Gaussling to sit at the rail intersection in his Colorado town and count rail cars clacking south in the dark of night, all full of molten sulfur from that other square state. I have counted as many as 85 cars in one train all stencilled with “Molten Sulfur”. All headed to, I presume, somewhere near the Gulf coast for, perhaps, sulfuric acid production.
I think we users of helium need to be a bit more vocal, or more curious at least, about the strategic reserves of helium. A lot of technology and sevices rely on it. Has anyone looked at the Marcellus and Utica reserves for helium??
Lamentations on Chemistry 