An example of some of the research we do in engineering. I collaborated on a small project to test how to apply antimicrobial copper coatings to the rubbery surfaces of escalator handrail materials, using a technology called “cold spray”. It’s essentially a high velocity shot of copper particles onto the surface, and my mechanical engineering colleague Prof. Jahed led the project with his expertise in this area. Getting metallic materials to permanently stick onto rubbery materials is no easy task, but this approach seemed to work pretty well. There are a lot of microscopic technical issues that need to be understood.
My other colleague, Prof. Marc Aucoin from Chemical Engineering and I helped assess the anti-viral and antibacterial efficacy of the material after coating. Basically we showed that it was pretty good and various viruses and bacteria died off at very respectable levels (over 99.99%) when exposed to the surfaces.
This was a nice collaborative project involving professors, students and other researchers from mechanical and chemical engineering, and a combination of materials science, virology and microbiology. The resulting article was published last year in the Journal of Thermal Spray Technology, and was recently picked as one of 6 “Editors Choice” articles in 2023 in that journal. Anyone can now read it without a subscription, at this link. I’m not sure where this might lead next, but it’s a small step forward in potentially reducing disease transmission in public areas.
In posts on accreditation of engineering programs, I mentioned that ethics, professionalism, health & safety, and environment are all expected outcomes that graduating students should have some familiarity with. When I was a student (a long long time ago) these topics weren’t emphasized much, but thankfully they are now. In courses I have taught, I try to inject some examples of technical areas where special attention is required to minimize risks to health, safety and the environment.
It’s commonly known that physicians have ethical responsibilities to not harm their patients. A bad or incompetent physician might harm patients one at a time, typically, but bad or incompetent engineers and other technical people can harm dozens or even thousands of people all at once. Here are a few examples that come to mind, some of which I’ve used as case studies in courses. These incidents are often due to a series of issues and are not usually caused by a specific engineer or other person. But they illustrate why we need to emphasize how to recognize and prevent these sorts of things in engineering education.
Imperial Sugar Refinery Explosion: In 2008, a dust explosion at a sugar refinery in Georgia killed 14 and injured 36. Poor design, maintenance, hazard identification and risk mitigation.
Hyatt Regency Walkway Collapse: In 1981, overhead walkways at a hotel in Kansas City collapse, killing 114 and injuring 216 due to structural overload. The original (adequate) design had been modified during construction, but without proper design change management and review. Something vaguely similar happened to Terminal 2E at the Charles de Gaulle airport in Paris in 2004.
Piper Alpha Oil Platform Explosion: In 1988 the North Sea oil platform had an explosion and fire that essentially melted it into the sea, killing 167 with 61 escaping. There were numerous failures that contributed to it, but they include poor design and management of change, inadequate hazard recognition and mitigation, poor safety management system, and poor training.
Bhopal Gas Release: In 1984 a chemical plant in India had a toxic gas release of methyl isocyanate leading to 3,787 deaths and 574,366 injuries. Estimates vary, but the numbers are staggering no matter what the exact numbers. Again, there is a host of issues but they include: poor maintenance on multiple pieces of equipment and instrumentation, inadequate safety system design, poor emergency response systems, poor management of change. This event stunned the chemical industry and led to major increases in attention paid to “process safety“, including in chemical engineering education and program accreditation.
Texas City Refinery Explosion: In 2005 a flammable vapour cloud release lead to an explosion that killed 15 and injured 180. As usual, multiple factors at play including: poor design and maintenance, poor safety culture in the company, overloaded staff, poor hazard identification and risk mitigation, lack of investment.
So those are a few examples, mainly from the chemical industry because that’s what I’m more familiar with. There is a whole bunch more posted on the U.S. Chemical Safety Board website (a good resource for teaching materials). There are probably lots of others from various sectors that I could look for, including the obvious and infamous Chernobyl nuclear disaster. If anyone has interesting other examples feel free to post some information in the comments.
Emergency hospital during 1918 influenza epidemic, Camp Funston, Kansas. (CC-BY-2.5)
There are some questions about whether the SARS-CoV-2 virus is more or less deadly than the 1918 influenza virus. It’s not really possible to accurately compare the two pandemics’ case and fatality data, for one very big reason. Oxygen!
Today, when someone has any sort of respiratory problem the first likely action is to provide supplementary oxygen. The air we breathe contains about 21% oxygen, which for a healthy person is obviously quite adequate. But for sick people, raising the concentration to near 100% can take the load off their heart and lungs and help prevent other problems like organ failure.
In the 1918 pandemic, the use of supplemental oxygen was not widely known or accepted (as illustrated in the picture, where no one is getting oxygen). There had been some experimentation and use in prior decades (and in treating some chemical weapons victims of the First World War), but it was not yet widespread. Even if it had been enthusiastically embraced, the supplies of oxygen were very limited and it was not readily available on an industrial scale. Therefore we read stories of even young and previously healthy people succumbing to the influenza virus within hours, turning blue due to lack of oxygen in their bloodstream. If oxygen had been available, many of them may have had a reasonable chance to survive and recover. Of course, today we have many other pharmaceutical interventions like steroids and monoclonal antibodies, none of which were available in 1918. But the oxygen is still needed to keep the patient alive long enough so that the pharmaceuticals can have a chance at working.
Where do we get the medical oxygen? There are smaller scale purifying units that take air and concentrate the oxygen in it using membranes to separate the oxygen from nitrogen. These are fine for portable use, smaller scales, or lower flows, but they are not readily scalable to the huge volumes required in a hospital and high-flow oxygen therapy. Likewise, oxygen cylinders are not very practical in hospitals due to their limited capacity. For example, the large “T” size cylinders (about 24 cm diameter by 130 cm tall) only contain about 9,000 L of oxygen once it is depressurized. For patients needing high flow oxygen therapy at up to 60 L per minute, the cylinder would only last about 3 hours or less. If there are a lot of patients, it would take a small army of people constantly moving cylinders in and out of rooms and the hospital. Unfortunately, in poorer and less industrialized parts of the world these options are often the only ones available.
The big industrial oxygen supplies are typically provided in the form of liquid oxygen, shipped and stored in specialized trucks and tanks. The liquid oxygen stored at the hospital is then vapourized into its gaseous form and piped to the patient rooms as required. This is a much more compact and efficient delivery system, since one hundred litres of liquid oxygen expands into about 85,000 L of gaseous oxygen for breathing purposes.
The large scale production and supply of liquid oxygen is a chemical and mechanical engineering accomplishment dating back to the early 1900’s. It took several decades for many plants to be built, with continuous improvements over the years to improve the process and reduce energy requirements. The industrial process uses distillation to separate oxygen from nitrogen (and argon and other trace gases) in air. Since oxygen and nitrogen have quite different boiling points (-183oC for oxygen, and -195.8oC for nitrogen), separation by distillation is a reasonably straightforward approach. However, distillation requires that air be liquified through a combination of pressure and low temperature, and this presents some significant engineering challenges.
Modern plants, often called “Air Separation Units” or ASUs, operate at pressures up to about 6 atmospheres and temperatures in the -170 to -190 range. Clearly it takes some significant compression and refrigeration equipment to carry this out, and the plants are carefully designed to be as energy efficient as possible. The video below, from one major manufacturer, gives a simple overview of the ASU process. Of course, ASUs are built not only for medical oxygen, but also for the many other industrial uses of oxygen such as in steel production, metal cutting, water treatment and chemicals manufacturing.
I’m currently not completely convinced that these “direct air capture” systems that remove carbon dioxide from the atmosphere are very practical. Technically they can certainly work, but the capital and operating costs are probably substantial, compared to the amount of CO2 you recover. However, if they do become widespread (as the linked article suggests), that will keep a lot of chemical engineers busy. And mechanical and electrical engineers too! And civil engineers during the construction phase.
Chemical Engineering is a low stress, high paying job according to this article! Another great reason to like it as a career path. See the article link below to find out how they decided this, and what the other 12 jobs are.
“In this way you must understand how laughable it is to say, ‘Tell me what to do!’ What advice could I possibly give? No, a far better request is, ‘Train my mind to adapt to any circumstance’….In this way, if circumstances take you off script…you won’t be desperate for a new prompting.”
Epictetus, Discourses
I ran across this quote from the early 2nd century Stoic philosopher Epictetus the other day (“The Daily Stoic” by Ryan Holiday). It reminded me that in engineering education we can’t possibly teach all the information and facts that one might need after graduation. In chemical engineering, for example, there are thousands of different chemicals, types of equipment, different processes for making so many different products. There are different methods for various pharmaceuticals, papers, metals, solvents, plastics, toothpaste, and the list goes on without end. There is a 27 volume Encyclopedia of Chemical Technology that covers many topics in chemical engineering, but even that has its limitations, even if some superhuman could actually learn everything in it. Forty-five years after starting a chemical engineering program in university and I’m still learning new things every week.
So no, we can’t teach everything an engineer might eventually need to know. We probably can’t even teach a small fraction of what people will eventually know or need to use. So we have to focus on training the engineer’s mind. How to approach problems, how to break them down into logical and manageable pieces. How to understand the science behind new situations. How to recognize the limitations of their skills and knowledge, and how they can address those knowledge gaps (it’s important to know what you don’t know!).
So when students of all sorts ask “why do we have to learn this, when are we ever going to use it?”, the answer may well be “possibly never”. But it’s part of the training of the mind, which definitely will get used eventually.
There aren’t very many positive things to say about a pandemic, but perhaps one positive outcome has been the successful advancement of mRNA vaccine technology. Although some people have the impression that this was very rapidly developed over the past year or so, the mRNA idea dates back to the late 1980s. It’s actually been undergoing development for 20+ years, although obviously the target wasn’t always the coronavirus. As a chemical engineer, I’m interested in the scale-up and production aspects, since that’s what we do best.
As a vaccine production method, the mRNA platform is exciting because it is so fast. Traditional vaccine production methods required the growth of batches of cells to produce the vaccine components. This cell growth is done in big tanks, sort of like beer brewing, but is typically slow. It may take many days or weeks to get one batch done. Some vaccines are still produced in chicken eggs (influenza) or cells grown in small “roller bottles” (measles). All of these are slow and difficult to scale-up to produce billions of doses.
The mRNA production method is not cell-growth based, it just uses a biochemical synthesis method. Here, you just mix a bunch of ingredients, add some enzymes to assemble the mRNA molecules, then enclose them in some nanoparticles. These nanoparticles are a key part of the product, and they serve a couple of key roles: 1) they protect the mRNA from degradation, since RNA is fairly unstable especially once injected into your arm; and 2) they provide the mechanism for the mRNA to get into your muscle cells where your body uses it to produce the “antigen” (the piece of virus protein that your body learns to recognize and fight, if you’re ever infected with the virus in the future).
This biochemical synthesis method can be done in a few hours, versus the days or weeks for the traditional vaccine manufacturing methods. There are still some purification and packaging steps involved which take some more time, but the overall process is still very fast in comparison to the older ones. The mRNA platform is very adaptable too, so the vaccine can be quickly modified if necessary, as the virus mutates, just by changing the “manufacturing template” (DNA plasmid) that assembles the mRNA molecules.
The Sartorius company (a science materials & equipment supplier) has produced a short video giving some information about mRNA vaccines and production, which is pretty good and not too technical.
After writing a recent post about helium supply and demand, this news article came up about a new helium production facility in Canada. I wasn’t aware that it was under construction, but it’s nice to see some Canadian progress in securing supplies of this important resource. The photo shows some typical chemical engineering design elements like piperacks, process vessels, separators, compressors, etc. How to put together a process like this, in a safe, sustainable, and economical way, is one aspect of chemical engineering education.
Saskatchewan is now officially home to the largest helium purification facility in Canada after opening in Battle Creek on Tuesday.
Each year, final-year students in Canadian engineering programs pursue open-ended group design projects (“capstone design projects”). This gives them the opportunity to combine the knowledge and skills obtained over the previous 3 academic years (plus work term experience for Waterloo students), and to tackle a problem that is a bit more challenging and wide-ranging than what a typical course assignment can cover.
Our Chemical Engineering class of 2021 has finished up their projects, and some short introductory videos are available for viewing. As usual, the projects are student-selected and they cover a wide range of topics from food processing to low carbon energy systems, reusable plastics to automotive parts manufacturing, and biotechnology to metallurgical processes. Allowing students to pick their own project topic let’s them tailor their experience to an area of interest, that perhaps they want to pursue after graduation.
Anyone interested in chemical engineering, or learning about the wide variety of things that chemical engineers can do, should have a look at some of the videos. They are each only about 1 minute long, give a brief high level overview, and can befound at this link.
Aside from being an English pronoun, He is the symbol for Helium, element #2 on the periodic table. The New York Times article discusses the uses and limitations around He supply, and is an interesting read. Over the last year, I’ve been on a PhD advisory committee for a student in Prof. Steven Young‘s group in the School of Environment, Enterprise and Development (SEED). His student is researching the “industrial ecology” of He, looking into where it comes from, how it’s used, and where the losses occur in the production, transportation and use. It’s quite an interesting issue, and I’ve learned a few things that might be of general interest.
We typically think of Helium use in balloons, or perhaps deep sea diving, but the major worldwide uses are in hospitals (for MRIs), specialized welding and manufacturing, and laboratories (for cryogenics or analytical equipment).
He is collected and purified from natural gas. It is produced during the radioactive decay of uranium in the earth, and collects in pockets of natural gas.
He is one of the few elements on earth that doesn’t have a “cycle”, like the carbon cycle or nitrogen cycle. That means, once it’s released into the air there is no natural way to get it back because it is so light and inert. It simply drifts away into the atmosphere and eventually leaves the planet.
He is so “light” (a small atom) that it is notoriously difficult to contain. It easily leaks and diffuses through materials, even solid metals. That’s why your balloon deflates after a couple of days, and why there are a lot of losses of He during transportation and use.
Since He is so important for some specialized applications, like MRIs, there are concerns that we need to conserve it. Also, since it is associated with natural gas, which we’re trying to scale back because of climate change, it may become more difficult to obtain. It occurs in the air at a concentration of about 5 ppm, so someday we may have to extract it from the air, like we already do with another related element, argon (Ar).
So Helium is kind of an interesting and important material. It involves chemical and mechanical engineering (for extraction, purification, and transportation), physics (for cryogenics, MRI and other applications), and industrial ecology (for understanding how it flows through our global economy, and what might happen in the future).
A Professor in Waterloo Engineering 