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Chemingineering | A Leaf out of Nature

K. Sahasranaman (Independent Industry Consultant)
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Chemingineering | A Leaf out of Nature

 

This month, our columnist provides a rundown on Artificial Photosynthesis, which has the potential to power our planet in the post-oil era. Advances in nanotechnology, material sciences and structural biology are helping us to not only mimic natural photosynthesis, but also improve its efficiency. The race is on to invent inexpensive, eco friendly and efficient catalysts.

Artificial Photosynthesis is currently the holiest of Holy Grails for the human race. By solving the twin problems of energy and environment, we can hope to extend our lease on planet earth. Artificial Photosynthesis seeks to mimic the naturally occurring process in plants and harness the power of solar energy to produce renewable fuels that will sustain our civilisation in the post-oil era.

Photosynthesis

Photosynthesis occurring in nature is an extremely complex process involving a number of steps, that are yet to be fully understood. In the first step, large antennas of light-absorbing molecules, such as chlorophyll, harvest sunlight and transfer their energy to the reaction centre. Photosystem II, a protein complex, uses the energy of photons to strip electrons from water molecules, thereby splitting them into hydrogen ions and oxygen. While oxygen gas is expelled into the atmosphere, the electrons and hydrogen ions are passed down a chain of proteins to synthesise Adenosine Triphosphate (ATP) and finally build sugars from carbon dioxide and water using enzymes.

There are two ways in which we can tap the potential of artificial photosynthesis. First is to stop after the intermediate step and use the hydrogen generated by splitting of water, as a clean fuel to power the much touted hydrogen economy. But since hydrogen handling and storage are cumbersome, it would be prudent to allow the photosynthesis process to continue its course and manufacture fuels in liquid or solid form. This is done by using the hydrogen generated to reduce carbon dioxide to carbon monoxide and produce methanol, for example, or further long chain carbonaceous compounds. The obvious advantage of this is that it uses up carbon dioxide from the atmosphere, thereby providing a welcome mitigation of global warming.

There are two approaches to artificial photosynthesis. One approach is to tinker with the biological processes and supplement them with synthetic materials. This semi-artificial method seeks to achieve synergy by combining natural processes with novel materials. The second method is to replicate the natural process externally using shapes and structures similar to that occurring in the cellular world. This approach leverages the extraordinary leaps we have made in nanotechnology and material sciences. Both the approaches have the objective of improving the efficiency to commercially scalable values.

Semi-artificial Photosynthesis

Semi-artificial Photosynthesis uses a hybrid system combining natural enzymes and synthetic materials to obtain a synergistic boost in the conversion of solar energy. It marries the self-healing properties of natural materials and the robustness of synthetic materials. Photosystem II, the naturally occurring protein complex, has been integrated with synthetic light absorbers, thereby enhancing the efficiency of the water-splitting reaction. Further, Photosystem II, synthetic light absorbers and polymers have been wired up to facilitate faster flow of electrons.

Hybrid systems widen the spectral range of the absorption of sunlight and increase the efficiency of reaction pathways. With improved understanding of structural biology, it is now possible to engineer enzymes for improved biocatalytic efficiency. Recent reports describe a biohybrid system in which nanoclusters of a biocompatible material like gold are incorporated inside bacteria to achieve intimate contact between photosensitisation and reaction pathways to speed up the electron transfer. Combining biological and inorganic materials is a challenge that hybrid systems have to overcome.

Another exciting development concerns hydrogenase, an enzyme occurring in algae, with the ability to split water. But since it was not necessary for survival, the plant genetically switched off the enzyme’s activity. After lying dormant for several millennia, researchers have now found ways to reactivate hydrogenase. Coupling hydrogenase and Photosystem II have yielded promising results.

Artificial Photosynthesis

Artificial Photosynthesis requires catalysts, not only to replicate the natural process, but also to raise the efficiency from the abysmally low values. We have come a long way since the pioneering work of Fujishima and Honda in 1972, when they accomplished photocatalytic splitting of water using Titanium Dioxide. Graphitic Carbon Nitride and semiconductor-based oxides of Zinc, Iron, Copper, Cobalt, Tungsten etc. are some of the photocatalysts that have been studied in great detail by several researchers in recent years. Structural morphology of the catalysts is extremely important for their optimum performance. Catalysts are often used in the form of nanorod or nanowire. Today, advances in nanostructure engineering make it possible to tailor catalysts with specific activity and functionality. Nanoparticles made out of Porphyrin and Fullerene molecules have yielded good results. Some of the successful catalysts are expensive, toxic and made from scarce resources. The race is on to invent inexpensive, eco friendly and efficient catalysts.

Evolutionary Inefficiency

Natural Photosynthesis is an extremely inefficient process with barely 1-2% of solar energy converted into sugars. The chief culprit of this inefficiency is the enzyme RuBisCo, which incidentally is the most abundant protein on earth. But three billion years ago, when photosynthesis probably first happened, RuBisCo was effective because our environment had more carbon dioxide and less oxygen than today. Today’s higher concentration of oxygen in the environment has impaired the performance of RuBisCo. Many scientists are now seized with the task of modifying RuBisCo so that it functions more effectively in fixing carbon dioxide into sugars.

Plants have not improved the efficiency of photosynthesis despite having billions of years to do so. They are satisfied with producing just the right amount of food required for their survival. Are we right in tampering with nature to fuel our greed? It is an ethical question with no easy answers.

Path Forward

Artificial Photosynthesis is more than a century-old idea. Giacomo Ciamician, an Italian Chemist first postulated the concept in 1912 as an alternative to fossil fuels. Depleting fossil fuels and global warming has renewed our interest in artificial photosynthesis in recent years. Solar Cells have made stupendous progress and are almost at the theoretical limits of their efficiency. While solar cells provide only instant power, artificial photosynthesis can manufacture storable fuels and chemicals. Advances in nanotechnology, material sciences and structural biology are helping us in our quest for this Holy Grail. While much of today’s work has provided proof-of-concept in the laboratories, commercialisation appears at least a decade away.

Reader’s responses may be sent to k.sahasranaman@gmail.com or chemindigest@gmail.com

Chemical Industry Digest- November 2018

Chemical Industry Digest
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Chemical Industry Digest- November 2018

Articles covered in November 2018 issue:

Recent advances in crystallization technology
Dr. Vivek V Ranade, Mr. Ajinkya V. Pandit, Dr. Rahul S. Bhambure.
The article gives an overview on the recent advances in the evolution of crystallization
technology with respect to process analytical technology, batch crystallization and continuous crystallization and also gives experimental details on some fine chemical crystallisation.

Bulk Material Handling Bucket Elevators
S Raghava Chari, Independent Consultant
Bucket elevators are the workhorses of bulk material handling systems. The article enlists
different types of bucket and belt elevators used for bulk material handling and gives salient
information and maintenance tips through various case studies.

Dimethyl Ether (DME): A Clean Fuel
Thirumalaiswamy Raja, Vipul S Patil, Siva Prasad Mekala, Chinnakonda S. Gopinath.
Since the need for a clean and alternative fuel has increased in the recent years, there has been a huge global demand for Dimethyl Ether (DME) as it is considered as the second generation fuel/biofuel and is much more cleaner. The article discusses on how DME can be used as an alternative to diesel and LPG. The article also provides synthesis routes for its commercial production.

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Leopold Ruzicka (1887–1976)

Veena Patwardhan
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Leopold Ruzicka (1887–1976)

All his life, the great Croatian-Swiss scientist Leopold Ruzicka maintained an enormous interest in the chemical processes of nature. His experimental work reveals his single-minded preoccupation with the chemistry of natural products. In 1939, he was awarded the Nobel Prize in Chemistry for his pioneering work on polymethylenes and terpenes (odorous chemicals produced by animals and plants).

A natural product organic chemist par excellence

Leopold Ruzicka began painstakingly investigating natural odorous compounds in 1916, and in a few years, made the ground-breaking discovery that the molecules of the naturally occurring musk perfumes—muscone (obtained from the musk deer) and civetone (sourced from the civet cat)—contain rings of fifteen and seventeen carbon atoms respectively. His discovery created a sensation in the field of organic chemistry because at that time it was believed that molecules with rings of more than eight carbon atoms would be too unstable to exist.

Ruzicka’s discovery was also a heroic one, achieved in the face of great experimental challenges, considering that he investigated the structure of molecules using only the chemical methods known at that time. In contrast, for work of a similar nature, since the last few decades, chemists have been using more advanced analytical methods such as spectroscopy and X-Ray analysis.

And not only did the discovery of the structure of muscone and civetone pave the way for further research on such large ring compounds, Ruzicka himself went on to synthesise these two odorous substances in his laboratory. This achievement caught the interest of the perfumery industry. For thousands of years, musk had been extensively used for preparing perfumes. But, for obtaining natural musk, large numbers of the endangered musk deer had to be killed. Today, thanks to Ruzicka’s research work, the perfume industry almost exclusively uses synthetically prepared muscone.

Early life and career

Leopold Ruzicka was born on 13 September, 1887, in Vukovar, a small town on the Danube in present-day Croatia. His father was Croatian while his mother was of German descent. The frequent riots and political unrest in his home country, made him move to Germany to study at the Karlsruhe Institute of Technology for his university education. Here, he completed his laboratory courses in less than two years and then immediately commenced his doctoral work on ketenes, studying under the young professor Hermann Staudinger who, at 27, was only 6 ½ years older than him.

Ruzicka received his doctorate degree in 1910, and when Staudinger took up a new position at the Swiss Federal Institute of Technology in Zurich (ETH), Switzerland in 1912, he joined him there as his assistant. The two of them then began research work on pyrethrins, natural insecticides extracted from chrysanthemum flowers. By 1916, Ruzicka decided to work in a research field of his own choice and commence his own scientific career. He was happy to be able to spend time from morning to night at his laboratory bench. But, with his part-time teaching job at the University of Zurich being as good as an honorary job, to meet his living and laboratory expenses he had to seek industry collaboration. He received Swiss citizenship in 1917, and was appointed as a professor at ETH few years later.

In the beginning, Ruzicka had to make time for teaching and researching simultaneously at ETH and the University of Zurich. From1926 till 1929 he taught as Professor of Organic Chemistry at the University of Utrecht in the Netherlands, but chose to return to ETH in 1929 on being offered the position of Director of its analytical laboratory.

Being keenly interested in terpene chemistry, Ruzicka had first turned to the perfumery industry for financial backing of his research work. But, following two unsatisfactory attempts at industrial collaboration, finally in 1921, he entered into a successful partnership with the Geneva perfume manufacturers Chuit, Naef & Firmenich. After focusing on investigating natural odours from 1916 to 1924, Ruzicka then moved on to researching other large ring molecules like steroids and hormones and by the mid-1930s unravelled the molecular structure of the male sex hormones—testosterone and androsterone and then went on to synthesise them. At that time, his laboratory was among those at the forefront of hormone research in the world.

Resolute opposition to the Nazi regime

A few years later, when the Nobel Prize in Chemistry was conferred on Leopold Ruzicka, World War II had just broken out. Though uninterested in politics during his youth, Ruzicka now openly professed his opposition to Hitler’s government, going as far as to helping many Jewish scientists to escape from Nazi-occupied countries to neutral Switzerland, and even employing some of them in his laboratory. Ruzicka was also one of the founding members of the Swiss-Yugoslav Relief Society.

A lover of science and art

During the war years, with many works of art being sold at slashed-down prices, Ruzicka, who had for long nurtured an interest in 17th century Dutch paintings, invested a considerable amount of the money he earned from royalties on patents into establishing a foundation for a small personal collection of exquisite Dutch paintings at the Kunsthaus in Zurich. He had to take a break from his scientific work and spenr time on travel to acquire the paintings.

The Ruzicka collection at the Kunsthaus that includes works by renowned artists such as Adriaen Brouwer, Jan Brueghel, Rembrandt, Rubens, and many others, attracts a large number of art lovers.

Ruzicka was also an ardent gardener, devoting a lot of time to tending to his plants. Another hobby of his was colour photography. His great fondness for paintings and photography seems quite interesting considering he was severely colour-blind, finding it difficult to distinguish the colour red. They say his friends would joke about this shortcoming suggesting that it explained his leftist political views.

A return to chemistry

Towards the beginning of the 1950s, there were important changes in Ruzicka’s personal and professional life. In 1950, he and his first wife Anna, whom he had married in 1912, got divorced after a childless marriage. The following year, at the age of 64, he married Gertrud Acklin, the mother of a grown-up son.

Around this same time, he returned to the field of chemistry after a break of a few years, to find that the methods and techniques for studying molecular structures had fundamentally changed by now. Researching by purely chemical methods had been replaced by physical methods like molecular spectroscopy and X-ray crystallographic analysis. Realising the advantages of adopting these modern methods, he acquired the necessary instruments and equipment and saw to it that trained people were available for taking care of and maintaining them.

Also, Ruzicka’s interest had now shifted to biochemistry, particularly to the biogenesis of terpenes and steroids, substances on which he had carried out pioneering chemical research in the past. This phase in his professional life marked another major achievement on his part. While researching terpenes earlier, he had extensively applied the then in use ‘Isoprene Rule’. Now, over a decade later, in 1953, he proposed his own ‘Biogenetic Isoprene Rule’ that replaced the former rule and soon received universal acceptance.

Till this time, biochemistry was being taught in Switzerland mostly as a preliminary and ancillary discipline. Ruzicka vigorously campaigned for the establishment of a separate Chair and laboratory of biochemistry at ETH. His efforts finally met with success in 1956, just before he retired.

Awards and recognitions

As a tribute to Ruzicka, when he retired in 1957 at the age of 70, the Swiss chemical industry contributed towards establishing the Ruzicka Prize at ETH. Each year, this prize is awarded for outstanding work done by young Swiss chemists or chemists working in Switzerland.

In 1974, Ruzicka’s native Yugoslavia honoured him with the Order of the Yugoslav Flag with Golden Wreath. In his home town Vukovar, the house where he was born has been converted into a modest-size Ruzicka Museum.

Apart from the Nobel Prize, some of the other major honours conferred on him include the Marcel Benoist Prize—Switzerland’s highest scientific award, eight Honorary Doctorates, and Honorary Fellowships of a number of reputed societies. He was also an honorary member of the American Academy of Arts and Sciences.

A prolific writer, he continued writing even in his old age, his 583 publications spanning a period of sixty years. Most of these however were published between 1930 and 1950.

Leopold Ruzicka died on 26 September, 1976 at the age of 89 in Mammern in Switzerland, a village on Lake Constance. He succumbed to the after-effects of a surgery he had undergone.

When America’s Harvard University awarded Ruzicka an honorary doctorate in 1936, Dr. James B. Conant, Harvard’s President, had aptly lauded him as, “A chemist daring in his attack, brilliant in his methods, successful in his interpretations of the architecture of nature’s baffling compounds.” It was a worthy tribute to one of the great men of science.

References

1. NobelPrize.org: Leopold Ruzicka – Biographical – Nobel Media AB 2014, https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1939/ruzicka-bio.html
2. Soylent Communications: Leopold Ruzicka – http://www.nndb.com/people/427/000100127/
3. University of Zurich: Leopold Ruzicka – Nobel Prize in Chemistry 1939 – http://www.uzh.ch/en/about/portrait/nobelprize/ruzicka.html
4. Michigan State University, Department of Chemistry: Leopold Ruzicka – https://www.chemistry.msu.edu/faculty-research/portraits/leopold-ruzicka/
5. Vladimir Prelog, Oskar Jeger: Leopold Ruzicka, 13 September 1887 – 26 September 1976 – Biographical Memoirs of Fellows of the Royal Society, 26, 411-502, 1980
6. Albert Eschenmoser: Leopold Ruzicka – From the Isoprene Rule to the Question of Life’s Origin – Chimia44 (1990) Nr. 1-2 (January-February).

Iron – A workhorse of an element

Veena Patwardhan
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Iron – A workhorse of an element

From playing the role of a vital building block of steel to helping produce chlorophyll in plants and in carrying oxygen in the blood of humans and animals, iron is a hardworking element, busy helping sustain life on Earth in myriad ways.

A brittle, hard substance, with a shiny, silvery grey appearance, iron is classified as a transitional metal in Group 8 of the Periodic Table. It is the most abundant of all metals, the cheapest metal, and also the metal that is used the most in the world. Around 90% of all the metal that is refined today is iron, most of it being used to produce steel, an important and versatile alloy of iron and carbon. The pure metal is chemically highly reactive and corrodes rapidly on being exposed to moisture and high temperatures. It is present in the combined form in most igneous rocks. The most common ore of iron is haematite, its other widely distributed minerals being magnetite and taconite.

A major part of the Earth’s solid and liquid cores is thought to be made up of iron. The electric current produced by the liquid iron in the Earth’s core creates the magnetic field protecting the planet. In addition to being found abundantly on Earth, Iron is also found in large quantities in the sun, the stars, and in the cores of all of the planets in our Solar System. The large amount of iron oxide on the surface of Mars gives this planet its red colour.

A long and interesting history

According to archeologists, people have been using iron for more than five millennia. Almost all of the iron used in ancient times came from meteors that fell to Earth from the sky. This has been proved from the composition of ancient iron artifacts that have been found to contain around 7.5% nickel, matching the typical composition of meteorites known as siderites. Such old iron artifacts, many of which have been found in Egyptian tombs dating back to around 3500 BC, could resist getting rusted on account of their nickel content.

As for iron smelting, its history can be traced back to around 1500 BC when the ancient Hittites of Asia Minor (Turkey) seemed to have discovered how iron could be smelted from its ores. But they managed to keep this process a secret for a long time, because this new metal, from which they prepared various weapons of war, gave them their economic and political power. The discovery of iron smelting led to the widespread use of iron and the commencement of a period in world history called the Iron Age.

In 585 BC, the Greek philosopher Thales reported that pieces of a type of iron ore had the power to attract iron filings. These pieces of the ore were called magnets after the place from which they came to a place called Magnesia in Asia Minor. They were also called lodestones, and the iron ore is called magnetite. Ancient Greek potters were known to have used iron as a pigment. They had discovered that items of iron, when fired under oxidising conditions, would be red in colour (because of the formation of Fe2O3), whereas those fired under reducing conditions would be black (due to the Fe3O4 that was formed).

The 7-meter high iron pillar of Delhi dates back to around 400 AD and is famous for being rust-resistant. The secret behind its ability to stay uncorroded for over a millennium is believed to be the unique composition of the iron from which it was made.

Iron is commercially produced in a blast furnace by heating haematite or magnetite with coke and limestone at temperatures of around 2000o C. The pig iron obtained from this process contains around 3% carbon and other impurities, and is used for producing steel. Each year, around 1.3 billion tonnes of crude steel is produced worldwide.
Properties and uses

Like the other transition metals, iron is ductile, malleable, and a good conductor of heat and electricity. Iron has the most applications of all metals even today, its use ranging from the manufacture of tiny paper staples to building huge ships. The reason for its multitudinous uses is its alluring combination of low cost and high strength.

Around the time of the Industrial Revolution in the 18th century, when coke rather than charcoal began to be used for smelting iron, it resulted in cheap wrought iron becoming available for use in transport and architecture. The first all-iron bridge was built in England, in 1778, and then the nearby town was named Ironbridge after this historic bridge that is still standing today as a striking symbol of the dawn of the Industrial Revolution. The biggest benefit of large-scale production of iron was experienced by the transport industry with the invention of locomotives or Iron Horses (that’s what the first trains were called) followed by the development of the railways from around the 1830s.

Like the metal itself, alloys of iron too have numerous uses. The best-known alloy of iron is steel. Ordinary carbon steel is an alloy of iron containing a small amount carbon ranging from 0.1% for mild steel up to 2% for high carbon steels. Alloy steels are produced by mixing carbon steels with other additives such as nickel, chromium, vanadium, tungsten and manganese. These are even stronger and tougher than carbon steels and are used for bridges, and in the manufacture of products like electricity pylons, bicycle chains, and cutting tools. Stainless steel contains at least 10.5% chromium. It is highly corrosion-resistant and used for making cutlery and cooking utensils.

Iron’s amazing magnetic properties make it useful for devices like electric motors, generators, and transformers, to mention a few. In the 1830s, Joseph Henry developed the first powerful electromagnet in the world. Nowadays, iron is alloyed with rare earth elements like neodymium to produce very powerful small magnets.
The Haber process for producing ammonia, and the Fischer–Tropsch process for converting syngas into liquid fuels make use of iron catalysts.

Iron’s biological role

Iron is essential for all forms of life. Most of the iron in our bodies is in the haemoglobin in our blood. Iron is an important nutrient for humans who need to have around 10-18 mg of it in their diet every day. A lack of iron causes anaemia and fatigue and a reduced capacity for physical work and is also linked with depression and impaired memory in teenagers. Iron sulphate is used for treating iron deficiency. On the other hand, increased iron levels in the body could lead to cardiovascular problems, and an accumulation of iron in the brain could increase the risk of developing Alzheimer’s disease.

Future uses

In recent times, researchers are working on the development of inexpensive and environment-friendly solar cells through the use of iron-based dyes. Iron, being much cheaper than the more expensive and rare metals used currently, will lower the cost of producing solar cells and light catchers.

Scientists are also researching the use of polymer-coated iron oxide nanoparticles for breaking up clusters of bacteria, and facilitating more effective treatment of chronic bacterial infections, particularly hard to treat hospital infections.

In today’s computer and internet age, we often tend to get overwhelmed by the benefits we enjoy due to advances in consumer electronics products. But if we stop to think about it, we would realise that surviving without microchips and modern gadgets would still be possible. In contrast, though we hardly pay any attention to this plain truth, we depend so much on steel in our day to day lives that it would be impossible to live without it. And as long as man’s aspirations continue to expand and diversify, the need and the demand for steel in construction, transport, and for countless other uses will only continue to grow.

References

  • Royal Society of Chemistry: Iron -http://www.rsc.org/periodic-table/element/26/iron
  • Agata Blaszczak-Boxe: Facts about iron – 22 August 2017, https://www.livescience.com/29263-iron.html
  • World of Molecules: Iron – https://www.worldofmolecules.com/elements/iron.htm
  • John Elmsley: Iron – Nature’s Building Blocks: An A-Z Guide to the Elements, p 205-211, 2001
  • Radio Chemistry Society: Iron – https://www.radiochemistry.org/periodictable/elements/26.html
  • Petter Persson: Solar cells of the future could be based on iron molecules – Phys.org, 18 May, 2016, https://phys.org/news/2016-05-solar-cells-future-based-iron.html
  • University of New South Wales: Nanotech weapon against chronic bacterial infections – 21 Dec, 2015, http://www.understandingnano.com/iron-oxide-nanoparticles-bacteria.html
  • Los Alamos National laboratory: Iron – https://periodic.lanl.gov/26.shtml

Chemingineering | The Future Fuel

K. Sahasranaman (Independent Industry Consultant)
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Chemingineering | The Future Fuel

 

This month our columnist takes a look at some recent advances in Hydrogen Fuel Cells, which are likely to power our vehicles in the near future. Fuel Cells have many advantages over battery in an automotive application but are expensive due to the use of a Platinum catalyst. Most of the current research is directed toward reducing or eliminating platinum.

With the Brent Crude firmly set on a northward journey, the time has never been riper to seriously look at alternatives for powering our vehicles. Many countries, including India, have already set the roadmap for switching over to electric vehicles as part of their larger commitment to the Paris Accord. Two technologies are available to provide the energy for electric vehicles – Batteries and Fuel Cells – and they are in healthy competition with each other. Most electric vehicles today use batteries, but the jury is still out on the matter. Fuel Cells have several important advantages over batteries, the most important of them being their higher energy density. The energy to weight ratio of Fuel Cells is at least 10 times more than batteries. Compared to battery-operated cars which need several hours for charging, Fuel Cell powered cars can be quickly refueled in minutes at hydrogen filling stations. While the battery technology is still evolving to extend the mileage between recharges, fuel cell powered cars are already miles ahead on this metric. The main bane of fuel cells continues to be their exorbitant cost. Fuel cell powered cars are at least twice as expensive as the average conventional car. Another related problem is the safety and cost of storing and transporting compressed hydrogen.

Fuel Cell

The first Fuel Cell, or “Gas Battery” as it was known then, was invented in 1839 by Sir William Robert Grove, who used Platinum electrodes. Platinum continues to be the mainstay of fuel cells and is the primary reason for their high cost. Grove’s invention never took off and lay buried for decades before it was resuscitated by NASA in the 1960s for their space programme. The fuel cell produced electricity and drinking water for the astronauts. A Fuel Cell is an electrochemical device that uses hydrogen and oxygen to produce power and water. Many different kinds of chemistries are available and the Proton Exchange Membrane (PEM) Fuel Cell is the most commonly used in vehicles. It uses a polymer as the electrolyte and platinum-based electrodes.

Platinum Catalyst

The main cost component of the fuel cell is platinum, which is used as a catalyst to speed up the chemical reaction between hydrogen and oxygen inside the cell. At the anode of the PEM fuel cell, hydrogen molecules are split into protons and electrons. The protons travel through the membrane to the cathode. The electron flow provides the external current before re-joining the protons and oxygen molecules at the cathode to form water. Both the reactions, especially the latter are sluggish and need to be speeded up by a catalyst if the chemical energy has to be converted into electricity at a rate useful for powering a car. Platinum has been the most widely used catalyst. The Platinum requirement for the cathode is nearly 10 times as much as for the anode.

Alternative Materials

Efforts to develop a cheaper alternative to platinum have been underway for several years now. Researchers at the University of California have developed a catalyst made out of porous carbon nanofibers embedded with compounds of cobalt, nickel or iron. The cost of these alternative materials is at least two orders of magnitude lower than platinum. Another band of researchers from the University of Wisconsin – Madison also use cobalt catalyst but in an entirely unique way. The problem with using less expensive metals like cobalt as catalysts are that they have to be used in much larger quantities. This lowers the efficiency of the cell. To overcome this problem, this team packed the cobalt catalyst into a separate reactor located adjacent to the fuel cell. Quinone is used to transport the electrons between the fuel cell and this reactor. Since Quinone degrades into a tarry substance after repeated use, the trick was to develop a stable derivative of quinone to perform this job. Much improvement, however, needs to be carried out on this design is currently the energy output is only a fifth of what a conventional fuel cell produces. A team from the University of Delaware have experimented with a non-platinum catalyst. They have used nanoparticles of tungsten carbide and claim that this not only brings down the cost of the cell but also improves the life of the membrane.

Catalyst Structure

Another approach to lower the cost of fuel cells is to reduce the quantity of platinum, by alloying it with other metals. Researchers at Brown University have alloyed platinum with cobalt in nanoparticles. Initial testing showed that the alloy catalyst performed better than pure platinum, but over prolonged use, cobalt got leached away rapidly. The research team developed a special lattice structure to address the leaching problem. While the outer shell is made from pure platinum, the inner core consists of alternate layers of cobalt and platinum. After successfully testing the new catalyst structure in a laboratory setting, the team tried it out in the real environment of the fuel cell, which is hotter and more acidic. This testing showed great promise as it beat the targets set by the US Department of Energy for initial activity and long-term durability.

Auto Industry

While scientists and engineers are racing to improve the economics of the hydrogen fuel cell, it also has the backing of Toyota, world’s foremost automobile manufacturing company. Toyota is betting big on the Hydrogen Fuel Cell, as opposed to some others like Tesla and Nissan who are pursuing the battery option. Having pioneered the mass production of the first fuel cell powered car, Mirai, in 2014, Toyota now plans to ramp up the production ten-fold to 30,000 units by 2020. Toyota has also developed a fuel cell powered truck. Market analysts say that it is this long haul segment, where the customers demand more range between charging, that makes the optics of fuel cells better than batteries. And just last month, the world’s first hydrogen-powered train started operation on a 60-km track in Germany. Alstom plans to build more such trains as several European countries have expressed interest.

Notwithstanding the current popularity of battery-operated vehicles, a survey shows that automobile industry leaders have more faith in Fuel Cell technology. It is expected to attract significantly higher investment in the years leading to 2025. At least 10 other automakers, including Honda, Mercedes, and BMW, are planning to roll out fuel cell cars by 2021. Advances in chemistry, catalysts, and materials will play a significant role in this evolution of transport.

Reader’s responses may be sent to k.sahasranaman@gmail.com or chemindigest@gmail.com

Chemical Industry Digest- October 2018

Chemical Industry Digest
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Chemical Industry Digest- October 2018

Articles covered in this issue:

Prospects and Potential of Value Added Products from a Biorefinery
Gangagni Rao Anupoju, Sameena Begum, Sudarshan Juntupally, Vijayalakshmi Arelli, IICT- Hyderabad. 
As petrobased feedstocks are finite and diminishing, bio-based renewables are increasing in importance. Biorefineries can produce a variety of products. Biorefineries could become a major contributor to the bio-based economy of the nation, according to the author.

Challenges in Getting Instrumentation Data for Mechanical Packages
Hemantkumar J Patel, Jitender Nasa – Fluor Daniel India Pvt. Ltd.
This article enlists the challenges and solutions while handling mechanical packages during detailed engineering. Any hurdles during handling will lead to delay in engineering activities and will impact the project schedule as well.

Piping Specialty Items
Nikhil Jagtap, Raghuraj Puri, Ramkumar Shanmugavelu, V Pranjal, Fluor Daniel India Pvt Ltd.
This article discusses in detail the various requirements for design, testing of piping items from a manufacturing perspective with respect to the two important piping specialty items: steam traps and flame arresters.

Electrochemical Processes and Industry – A Review
Dr. N C Datta, Independent Consultant
There are chemical products which can be best produced only through the electrochemical route. Making the process energy efficient is a challenge. Core developments of the two most important electrochemical industries, vizchlor-alkali manufacture, and aluminium
extraction are described.

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Challenge in Getting Instrumentation Data for Mechanical Packages – Hemantkumar J. Patel, Jitender Nasa

Chemical Industry Digest
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Challenge in Getting Instrumentation Data for Mechanical Packages – Hemantkumar J. Patel, Jitender Nasa

Abstract
Detail engineering of mechanical packages (e.g. various compressors, N2 plant, boiler package etc.) has always been a challenge for control systems engineer in terms of getting the proper data in time. If the required data is not available in-time, it will delay the engineering activities and ultimately may impact the project schedule as well.
Hence meeting the required schedule and data, it is very important that the Mechanical packages should be handled very carefully from the beginning i.e. from the basic engineering, as well as detailed engineering stage.

Identification Of Challenges
One of the common issues is that ordering of mechanical packages is delayed and is not suitably linked with control systems deliverables, which typically results in further delay in engineering activities. The control systems scope can be considered the most important scope in terms of quality, safety and overall performance of the mechanical package, so proper attention/focus should be at par with other discipline deliverables.
Below are listed some of the Challenges that an instrumentation engineer faces during the detail engineering activities of mechanical packages.
u Project standard Legends, Symbols and Tagging in Piping & Instrumentation Diagram (P & ID)
In many cases, the mechanical package P & ID Legend, symbols and tagging are not aligned with the main plant P & ID. Also, the interface of the mechanical package P & ID is not aligned with the main plant P & ID.
u Input data in Prescribed Format:
Many times it is noticed that the Vendors do not submit data in the format requested by the control systems engineer. This is applicable for following deliverables:

  • Input-Output List
  • Cause & effect matrix
  • Process control narrative
  • Safety narrative
  • Instrument datasheet
  • Instrument Index
  • Instrument location plan
  • Instrument air supply layout etc.
  • Junction box grouping, cable schedule etc.
     Focus on Vital data:
    When inputs are requested in prescribed formats, they often contain information and details which might not be within the scope of the vendor. The Vendor may not be able to provide all details in the first issue of the document.
    u Missing Information
    Sometimes the requirements per project specifications are not requested from the vendor and no confirmation is requested. Without confirmation that specification requirements are included in scope, it becomes very difficult for the vendor to comply with the requirements and this may result in implicating price and schedule. Such details may include:
  • Datasheet in .isf format for Smart Plant Instrumentation (SPI)
  • Approved make & preferred model number
  • Soft signal exchange list in prescribed format
  • Alarm & trip set points
  • Software and hardware requirements for Communication with Distributed Control System (DCS)
    * Too many comments on Vendor Drawings
    It has been observed that extensive comments are given on vendor documents which results in delaying the document approval cycle, as well as delaying the delivery of the package. This is especially true for documents that require manufacturing clearance.
    * Junction box and cabling scope are not properly defined.
    * Required Information for various utilities within the mechanical vendor battery limit.
    * During the finalization of long lead items, instrumentation department is not on-board and hence instrumentation part is kept untouched.
    * Sometimes vendor does not approve the deviations which may impact the later stage of the project during detail engineering.
    The above mentioned details are applicable for the mechanical packages which are being controlled from Main Plant DCS/Emergency Shutdown (ESD) system as well as the mechanical packages are being controlled from its own dedicated Programmable Logic Control (PLC) based control system.
    Possible Solutions to Overcome the Challenges
    It then becomes the responsibility of the Control Systems Engineer to get the right data in-time from mechanical package vendor. A few things that can be taken into the consideration while doing the detail engineering of mechanical packages are listed below:
    * Basic inputs like the legend, symbols and tagging philosophy need to be provided to the mechanical package vendor right at the bidding stage. Also separate tag series shall either be assigned for mechanical package scope tags or a numbering philosophy document for the particular job shall be followed.
    * The main reason that Vendors do not submit data in the prescribed format is because the formats are not shared with vendor during the bid evaluation stage. As a minimum, project standard templates / formats must be submitted during the kick-off meeting.
    * The more we ask the vendor to customize the more difficulty we face in acquiring the data to meet our schedule and the more we drive up cost. Although this might be thought to be an acceptable approach on a cost-reimbursable project, to give the Client everything he is asking for, is driving up cost and setting the vendor up (and ourselves) for failure. It is our responsibility to identify where client requirements are driving up project cost. On lump-sum projects, we must familiarize ourselves with the minimum requirements and take exception where we can to project requirements that exceed the minimum necessary to deliver a safe and operable package.
    * One of the main reasons vendors struggle to meet schedule for vendor data and ultimately delays shipment of the packaged equipment is the degree of customization placed on the vendor and the number of specifications included in the Request for Quotation (RFQ). Many package vendors do not keep a large staff of engineers available to review or assess the project specifications and to re-design or customize standard drawings during detail design. Often they must contract with a third party to redesign the controls. Fabrication stalls as vendor data is cycled multiple times until the customization is to the satisfaction of the consultant.
    * The very first thing a Instrumentation engineer should do is review all project specifications that might impact the packaged system with the intent to eliminate inconsistencies, conflicts, and unclear or non-applicable requirements. Next, work with the client to eliminate gold-plating and excessive customization noting that this will result in savings to the project and reduce schedule. Highlight where design margins are increased, footprint is increased, standard panels are re-designed, fabrication techniques changed, installation details modified and engineering deliverables are added to the vendor’s scope.
    * Once the client agrees to the streamlined set of requirements and/or specifications, integrate them into the RFQ technical notes. Ensure the Inspection and test checklist for packaged equipment is included in the set of specifications and the master document register lists the minimum required documents.
    * Collaborate with the mechanical responsible engineer to review proposals and clarify proposals. Participate in bid openings, vendor clarification and pre-award meetings. Clarification meetings is the time to request vendor typical drawings and assess if they contain the level of detail needed.
    * When assessing a package vendor’s standard design drawings, identify interfaces with other systems (both for control and utilities), scope breaks and how construction will be impacted.
    * When practical, let the vendor maintain his method of tagging for devices that are internal (instruments and devices not brought to the plant automation system). This can also be a practical approach to how vendor P&IDs and project P&IDs are integrated. Devices internal to the package system would not be shown on Project P&IDs, which shows the package as a black box. There are several ways to handle devices and signals that connect to the plant control systems or that are supplied as ship-loose for installation. They may be assigned a project tag in addition to the vendor’s tag, a cross-reference list provided by the vendor and vendor drawings updated to reflect both, or the vendor may agree to accommodate the project tagging in all his documentation. The former is the best solution for packages that are supplied as vendor standard packages with Unit Control Panels (e.g. Instrument air compressors, packaged boilers, etc.) and the second for equipment packages that are more complex with multiple skids and wired to the Plant Control System.
    * Reviewing equipment package vendor data should be coordinated by an Instrumentation engineer to achieve the following; eliminate or reduce cycling of data, eliminate addition of information onto a document that exists on a different document (e.g. duplication of project tags on all documents where a cross-reference exists), avoid comments that change the vendors design that had not been included in Purchase Order (PO), ensure all instrumentation and electrical reviewers avoid doing a quick scan with the intent of doing a more thorough review on the next cycle and avoiding cosmetic marks that have no impact on the design.
    * Prior to Inspection and test of equipment package, the instrumentation engineer and designer should be familiar with the minimum requirements and have confirmation from the vendor that all devices are installed, all controls are completely wired, the vendor has completed an internal test of the equipment and a set of the approved documents are available. The technical notes should contain a statement stating the vendor should return the completed inspection and test checklist with the notice of inspection.
    * An equipment package that is fully integrated with the plant automation system will require coordination between the Automation system supplier and the package vendor. During RFQ development of the equipment package, the instrumentation engineer responsible for package should coordinate with the Lead Automation Engineer to ensure all requirements for network(s) connectivity are included and specific to each package. If possible, a block diagram should be provided to the vendor to clarify the scope breaks and connection points. Confirm the package vendor data submittal dates and format align with the Automation System Supplier’s schedule and format for required deliverables. A map of internal addresses (Modbus map), communication protocol(s) and IP addresses is often an area that is not well coordinated and results in re-work for both package vendor and automation system supplier.
    Conclusion
    Hence to conclude on the subject, early alignment with package vendor is very much essential during the kick-off meeting immediately after the purchase order. All critical issues like formats to be followed, .isf datasheets for SPI, battery limit interface, junction box grouping, control narrative, C & E etc. should be thoroughly discussed and agreed between the agencies.
    References
    1. ISA, International Society of Automation.
    2. Image courtesy by Canadian Government Nuclear Laboratory
    3. Intergraph corporation for SPI
    Aknowledgements
    We would like to thank P.K. Midha, Control System & Electrical Head of Department, Fluor Daniel India Pvt. Ltd. for his continuous support and motivation in completion of this paper.
    We would also like to thank Leo Poszywak Subject matter expert – Control System, Fluor enterprises for his valuable inputs and support in completion of this paper.
    We would also like to thank Fluor New Delhi senior management for encouraging us to pursue writing of this paper.

Chemingineering | The 4th Revolution

K. Sahasranaman (Independent Industry Consultant)
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Chemingineering | The 4th Revolution

 

Our columnist presents Industry 4.0, which has the potential to transform the chemical industry in unimaginable ways. Though the principles are clear, the opportunities and risks are yet to be fully grasped. Among the challenges to usher this revolution is the fear of cyberattacks and the lack of trained manpower.

25 Years ago, acquiring authentic technical information was a herculean task. Firstly, we needed access to a good library that stocked journals covering topics of our interest. Having located the desired information, we had to leverage our influence and contacts to either borrow the journal or photocopy the relevant pages, the illegality of which never crossed our minds. Today, by the time you have read the preceding lines, Google would have thrown up results to your query. We take this remarkable transformation for granted, scarcely giving a thought to the underlying technology that is responsible for it. The suite of digital tools and technologies that are currently under various phases of trial and deployment have a similar power of altering our world unrecognisably in the decades to come.

Digital Technologies

Over the last 20 months, this column has repeatedly drawn the attention of readers to the power of some of these digital technologies. For example, Virtual Reality (The New Reality, January 2018) has the potential to transform education, research, design, construction, training, operation and maintenance in chemical industry. We examined the hype generated by Internet of Things (Things on the Internet, February 2018), wondering whether the industry has the ability to extract meaningful information from zettabytes of data generated by billions of devices. The disruptive and still little – understood technology of Blockchain (Unchaining the Blocks, December 2017) offers a platform of trust and transparency that can decongest the long and often complex supply chain of the chemical industry. Artificial Intelligence (AI+CI = ??, August 2017) holds the promise of new business model for the chemical industry, among a slew of other goodies.

Industry 4.0

The technologies described above, together with some more like Cloud Computing, Big Data Analytics, Robotics and 3D Printing constitute the 9 technological pillars of what is being touted as Industry 4.0, or rather Industrie 4.0, a strategic initiative by Germany to establish itself as a leading provider of advanced manufacturing solutions. Industry 4.0 involves real-time, intelligent integration of people, machines and objects to dynamically manage complex systems. The objective of such “smart factories” is to enhance resource efficiency – material, energy and manpower. Some of the benefits are pretty obvious. For example, enhanced predictive maintenance of machinery that will almost eliminate wasteful downtime and also improve the asset longevity. Other benefits are not easy to comprehend without tangible examples. For example, integration of customers and suppliers in an interactive and collaborative way to provide novel products and solutions–say, highly customised batches of specialty chemicals for individual customers.

Operational Excellence

The key objective of Industry 4.0 is to lower costs through operational excellence. Through measurement and monitoring of a large number of variables it is possible to optimise processes to a degree and level of sophistication that has not been possible hitherto. This will enhance production efficiency and also improve product quality. Process and product faults will be kept to an all-time low if not completely eliminated. Like processes, the entire supply chain will also be streamlined. This will improve flexibility in a competitive and volatile market. By tracking the product through its entire lifecycle, it will be easier to anticipate the requirements of the customer and respond faster. It will be possible to produce the exact products that customers need and deliver them exactly when they want.

Business Models

Industry 4.0 is expected to have far-reaching consequences on business models – changes in existing models and emergence of new models. It has the power to transform a commodity business into a solution provider. A company manufacturing paints, for instance, will morph into a solution provider for surface protection. The paint will no longer be sold on weight basis but on the duration of its protective performance. The new business model thus uses data-based value creation and propositions. There is a clear transition from offering product to providing solution.

The shift from product to solution creates a new opportunity for strategic differentiation and unique selling proposition in a highly competitive market. Data is the vital ingredient as companies fight to offer highly customised solutions. Intense and trustful relationships with customers are the key to success in such a model.

Challenges

Along with offering opportunities Industry 4.0 also poses challenges. The biggest of them is cyber security. The high degree of data transparency that is intrinsic to Industry 4.0 makes businesses vulnerable to industrial espionage and cyber attacks. This is perceived as a huge deterrent by many companies. At the same time Industry 4.0 creates an ecosystem that facilitates entry of competitors, who can stifle the established players by offering novel products and smart platforms. This dynamic reshaping of industrial boundaries will leave behind the old who dither and reward the new risk-takers. The biggest challenge for the adoption of Industry 4.0 comes from the employees, most of whom are not equipped, either technically or psychologically, for this hugely disruptive change. This is especially true for the management level personnel who are responsible to drive the change, as a significant number of them have completed their education in the pre-Internet era. But with the baton passing on to the younger generation, this is bound to change rapidly.

Epilogue

Industry 4.0 was intended to usher the fourth industrial age powered by digital technologies. Though originally designed for manufacturing industry, the principles of Industry 4.0 are equally amenable to the chemical industry, especially the specialty chemicals sector, where knowledge is king and batch processing is the norm. SMEs which rule this sector are fragmented and fiercely competitive. Industry 4.0 will help them gain significant cost and market advantage.

The chemical industry is a notorious laggard when it comes to embracing digital technologies. However, some elements of Industry 4.0 like process simulation, automation and advanced process control are already being practiced for decades. To hasten the process of digitalisation, we need to change the mindset of people and infuse fresh blood. And we can begin this process by imparting the necessary interdisciplinary skills in colleges. Not everyone understands the opportunities and risks of this fourth industrial revolution, but that shouldn’t deter us from taking baby steps towards a brave new world.

Readers’ responses may be sent to k.sahasranaman@gmail.com or chemindigest@gmail.com

Chemical Industry Digest- September 2018

Chemical Industry Digest
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Chemical Industry Digest- September 2018

Articles covered in September 2018:

Recent Advances in Engineering Aspects of Pharmaceutical Crystallization – Part II
K.Hemalatha, Dr S.Vedantam, Dr K.Yamuna Rani – IICT Hyderabad.
This article as a sequel to first part by the same authors, summarises recent developments from an engineering perspective in the key aspects of the crystallisation process of pharmaceuticals.

Storage Tanks’ Vapor Recovery Systems – Evaluation, Key Design Aspects and Implications
Vahidunnisa Qureshi, Srinivasa Oruganti, Fluor Daniel India.
This article describes different receovery systems that can be employed to storage tanks to reduce losses due to vapour formation.

SRU – Typical Challenges during Detail Design
DebopamChaudhuri, SaumyaSengupta, SrinivasaOruganti, Fluor Daniel India.
Detail design is always challenging and more so for Sulphur Recovery Units (SRU). Highlighting these challenges the paper outlines the design aspects. They are mostly linked with licensor induced changes, FEED Updates, Hydraulic challenges, etc.

Stripping Liquids from Gas / Vapours
S. Raghava Chari – Independent Consultant
Separating entrained liquids from gas / vapors is a very important function in many chemical processes. Liquids like water in boiler drums could damage the system. In this article, the author discusses in detail different ways of stripping liquids from gas/vapour.

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Chlorine – Toxic, but surprisingly useful

Veena Patwardhan
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Chlorine – Toxic, but surprisingly useful

Chlorine, the second lightest of the halogens is more closely linked to our everyday lives than most people think. It does more than just add flavour to the food all over the world in the form of sodium chloride. From computers to the credit cards in our wallets, from toys to tubing, from wall paint to plumbing pipes, from the flooring to the roof, it is present in every part of our homes and all around us… and even inside our bodies, in our blood, in the form of chloride ions that help maintain the right balance of electrolytes essential for the proper functioning of our cells and organs.

In the water we drink, the medicines we take, the furniture we sit on, the modes of transport we take, the mobile phones we use, chlorine chemistry is hard at work, keeping us safe and healthy, making our lives enjoyable and more comfortable.

Chlorine chemistry is also saving millions of lives annually. Even today, worldwide around 15 million people succumb to waterborne diseases every year. We can only imagine how appalling the health scene was around a century ago, before chlorination of drinking water was introduced for destroying bacteria and viruses that cause diseases like typhoid fever, cholera, dysentery, and Hepatitis A.

Around 1890, when it was discovered that chlorine was a powerful tool for disinfecting drinking water, the microbes that caused waterborne diseases were yet to be identified. But, given the sharp decline in deaths due to different diseases transmitted through water, it was amply clear that chlorine could destroy all or most of them. As LIFE magazine put it: The filtration of drinking water plus the use of chlorine is probably the most significant public health advancement of the millennium. Currently, chlorination is the most popular method adopted for disinfection and water treatment the world over.

Chlorine is the sixth most abundant element in the Earth’s crust. Our oceans too contain a huge amount of it—around 2.6 x 1016 metric tons, mostly as sodium chloride. Being aggressively reactive, chlorine easily combines with almost all other elements and is not found free in nature, occurring mainly as common salt, carnallite, and sylvite (KCl).

The luckless discoverer

Rock salt, the natural form of the most common compound of chlorine—sodium chloride—has been known to mankind since millennia. But the element (chlorine gas) was discovered only in the late 18th century. In 1774, the Swedish pharmacist Carl Wilhelm Scheele, while engrossed in carrying out one of his many experiments, heated hydrochloric acid and a piece of pyrolusite—a mineral that is mainly manganese dioxide. The reaction led to the discharge of a greenish-yellow gas. Though he didn’t know it at that time, Scheele had just discovered a new element—chlorine.

Scheele noted that the new gas had “a very perceptible suffocating smell, which was most oppressive to the lungs”, adding that it “gives the water a slightly acidic taste… the air in it acquires a yellow colour…” He also noticed the high reactivity and the bleaching qualities of this gas, describing some of his observations as “…all metals were attacked… fixed alkali was converted into common salt… all vegetable flowers—red, blue, and yellow—became white in a short time; the same thing also happened with green plants… insects immediately died.”

Unfortunately, despite such accurate observations, Scheele, going by the widely accepted ‘phlogiston’ theory of his time, thought the new gas was a ‘dephlogisticated’ form of muriatic acid (the old name for hydrochloric acid). For quite some time after that, many scientists were convinced that the gas Scheele had produced was a compound of oxygen. But, several decades later, in 1810, Sir Humphry Davy proved that the greenish-yellow gas was not a compound, but in fact an element. He suggested the new gas be called chlorine, deriving the name from the ancient Greek word ‘khlōrós’ meaning greenish-yellow or pale green.

Carl Scheele had given his life to chemical research and his many brilliant scientific achievements are widely acknowledged today. But sadly, he didn’t get the credit he deserved for many historic discoveries. His failure to publish and publicise his work in time, combined with his disinclination to attend meetings of the Royal Swedish Academy of Science, resulted in other well-known scientists getting credit for what he had discovered much earlier.

In the case of chlorine too, Scheele didn’t live to realise he was the discoverer of this important new gas. He died prematurely of several ailments including kidney failure in 1786 when he was just 43 (whereas Davy identified chlorine in 1810). Back then, there were few analytical tools and established testing methods, and hence, like the other researchers of his time, Scheele too would smell and taste the chemical compounds he tested or discovered, exposing himself to highly poisonous substances such as arsenic, mercury, lead, and hydrofluoric acid. All of these obviously played havoc with his health.

Today, chlorine gas is produced commercially through the electrolysis of sodium chloride sourced from seawater or brine from salt mines. An amazingly efficient production process, the by-products include hydrogen—used as an energy source in several manufacturing facilities, and sodium hydroxide—a versatile product used for manufacturing numerous consumer and industrial products.

A major and incredibly useful industrial chemical

With around 15000 chlorine compounds being used in industry today, chlorine is one of the most extensively used industrial chemicals and a major “building block” of industrial production.

Despite its evil-looking green-yellow colour, chlorine is one of the most beneficial elements.
Besides being used worldwide for providing safe drinking water to billions, being a powerful bleaching agent, a large amount of chlorine is also used in the paper and pulp industry. However, the most important use of chlorine is for making a host of useful chemicals such as chlorates and organic compounds such as chloroform, carbon tetrachloride, synthetic rubber, and polyvinyl chloride (PVC)—the extraordinarily versatile and durable plastic. Chlorine compounds in turn are used for manufacturing a range of products including dyestuffs, medicines, antiseptics, insecticides, household bleach, petroleum products, paints, and plastic items.

Chlorine products are used for:

  • Disinfection and Sanitation
  • Food production – By protecting crops from pests.
  • Healthcare – Chlorine compounds are also used for manufacturing blood bags, contact lenses, safety glasses, and respiratory inhalers.
  • Innovative Technology – Chlorine products play a major role in the manufacture of electronic devices, hi-performance magnets, air conditioning refrigerants, and hybrid car batteries.
  • Environment Protection – In multifarious way chlorine products help in mitigating environmental problems, like to produce light weight & fuel efficient vehicles, helping higher crop yields, thus reducing the need to convert rainforests etc.
    Chlorine is also a key player in the harnessing of solar energy, making it possible to obtain high-purity silicon from sand for making solar panel chips. The blades of wind turbines that help convert wind power into electricity are made from chlorine-based epoxy resins.
    Smarter and comfortable transportation
  • Protective equipment – Military and police personnel too benefit from the chlorine chemistry used in the manufacture of strong and heat-resistant synthetic fibres out of which protective gear like bullet-resistant vests, flak jackets, and helmets are made. Similarly, chlorine chemistry is also used for manufacturing parachutes and night vision goggles.

Toxic effects

The elemental profile of chlorine is akin to that of a person with a split-personality. It has a good side, and also a dark side. On the one hand, it is amazingly useful, satisfying a number of man’s needs; but, on the other, it is extremely dangerous. Inhaling chlorine gas even for a short period could have disastrous results. A respiratory irritant, it causes excessive accumulation of fluid in the lungs leading to breathing problems. It also irritates the skin, eyes, nose, and throat and can cause burns and ulcerations.

The toxic effects of chlorine gas led to it being used as a chemical weapon for a short time during World War I. In more recent times, terrorists in Iraq blew up tankers carrying chlorine so the released chlorine gas could claim the lives or badly injure Iraqi police and civilians.

Another dreadful chlorine-related story is that of DDT — dichloro diphenyl trichloroethane. When it was first introduced as a powerful pesticide, farmers were overjoyed. It effectively killed insects, rats, and pests that destroyed their crops. However, following the overuse of this pesticide, it was found that birds and fish that fed on insects sprayed with DDT or drank water containing DDT were killed in large numbers. Soon, harmful effects were detected in humans as well. Consequently, DDT came to be banned in many developed countries. At present, one of the few permitted uses of DDT is for controlling malaria by way of fumigation or spraying of the chemical. In sub-Saharan Africa, DDT has helped drastically reduce the deaths due to malaria.

Also, CFCs (chlorofluorocarbons) once widely used in refrigeration, air conditioning, and aerosol sprays were found to damage the Earth’s protective ozone layer.
Nevertheless, we cannot deny the fact that chlorine plays a very significant role in our lives, the many benefits it offers far outweighing its undesirable effects. Not to mention, chlorine has also helped to significantly increase our life-expectancy.

References

1. Dr. Doug Stewart: Chlorine element facts – Chemicool.com, 16 Oct. 2012, https://www.chemicool.com/elements/chlorine.html
2. American Chemistry Council: Chlorine Story – https://chlorine.americanchemistry.com/Chlorine/What-is-Chlorine/Chlorine-Story/
3. Justin Rowlatt: Chlorine: From toxic chemical to household cleaner – BBC News Magazine,
4. 19 April 2014, https://www.bbc.com/news/magazine- 27057547
5. Benjamin Brodsky: Industrial Chemicals as Weapons: Chlorine – Nuclear Threat Initiative. 31 July, 2007, http://www.nti.org/analysis/articles/industrial-chemicals-weapons-chlorine/
6. American Chemistry Council Chlorine Chemistry Division: Discover Chlorine – The Element of Surprise – https://www.elementofsurprise.org
7. Daryl Weatherup: Chlorine: Protecting human health for more than a century – Greenbiz.com, 14 November, 2016, https://www.greenbiz.com/article/chlorine-protecting-human-health-more-century
8. Agata Blaszczak-Boxe: Facts About Chlorine – LiveScience.com, 24 April, 2018, https://www.livescience.com/28988-chlorine.html
9. Safe Drinking water Foundation: What is chlorination? – https://www.safewater.org/fact-sheets-1/2017/1/23/what-is-chlorination
10. Gabe Paoletti: Carl Wilhelm Scheele: The Forgotten Scientist Who Discovered Oxygen – All That’s Interesting, December 6, 2017, https://allthatsinteresting.com/carl-wilhelm-scheele.

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