The Role of Chemical Engineers in Combating the Effects of Climate Change

Abstract

Climate change is the burning issue of this century. According to a recent major UN report, if we are to limit temperature rise to 1.5 °C and prevent the most catastrophic effects of climate change, we need to reduce global CO₂ emissions to net zero by 2050. This paper discusses 3 ways in which chemical engineers can contribute to the global combat against climate change. Two recent technological innovations in each method is put forth, and its advantages, disadvantages are discussed. Potential engineering problems and author’s opinions/viewpoints are mentioned.

Introduction

Chemical Engineers have always been an integral part of this society. Their roles can be highlighted throughout periods of time, and can be associated with the challenges at that period. For example in 1940 after the second industrial revolution had brought forth petroleum, electrical and steel industries, new concepts and innovations were put forth to thrive in the competition. At this time chemical reactors couldn’t be synthesized with unit operations alone, and chemical engineering brought forth the concept of transport phenomena that made them stand apart from chemists and mechanical engineers (Clive Cohen 1996). In 1950 the advancements in polymer science brought forth the age of plastics (Perkins 2003). Following suit, it only seems apt to discuss what the contribution of a Chemical Engineer can be towards the burning issue of this century, which is mitigating the impacts of Climate Change. According to a recent major UN report, if we are to limit temperature rise to 1.5 °C and prevent the most catastrophic effects of climate change, we need to reduce global CO₂ emissions to net zero by 2050(ipcc.ch). Chemical engineers have already been combating climate change in various fields such as carbon capture technology, water conservation, food sustainability, renewable energy sources, etc. However, there are always issues when it comes to major breakthroughs being commercialized. They can be in terms of cost, high energy demands or even policy issues. In this paper three of the many issues are taken, and two technological innovation of each field is analyzed, and a sustainable solution is given for overcoming the challenges they are facing.

Keywords: Chemical Engineering, Climate Change, Water Conservation, Food Sustainability, Renewable Energy, Desalination, Nuclear Energy, Condensation, Biofuel

Climate Change

Climate Change is the defining issue of our time. From fluctuating weather patterns that threaten sustenance, to rising sea levels that escalate the risk of flooding, the impacts of climate change are global and unpredictable. Without drastic action today, adapting to these impacts in the future will be more difficult and costly. Our society will has to undergo rapid, profound changes to mitigate the effects of climate change and adapt to changes that have already started to occur. But, the climate crisis also points to the massive opportunity to create jobs in a more green economy. This is where chemical engineers have a large scope of making a meaningful changes to this society.

Water conservation

Although three fourths of the earth is covered in water, only one percent of it is available for use. Clean water is going to be a constant necessity for survival of all living organisms. Chemical engineers have played a major role in water purification technologies, whether it’s establishing water treatment plants in industries, or discovering new water purification technologies. There are several ways to obtain freshwater such as Reverse Osmosis, Desalination, UV purification, etc. However each method still poses its own challenges and as a chemical engineer it is important to work on sustainable solutions for each challenge.

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For Example, desalination is a process that takes away mineral components from saline water. It is the most popular method of obtaining freshwater. The problem is that the desalination of water requires a lot of energy to break ionic bonds, as salt dissolves easily in water. This means that desalinating water can be pretty costly. A new desalination project planned for California, called The Pipe, was introduced in 2016. It operates on solar energy and uses electromagnetic desalination to turn seawater into fresh water, filters the salty residue, and flushes it back into the Pacific Ocean. The Carnegie Perth Wave Energy Project does double duty, generating energy from the tides while simultaneously desalinating seawater. A built-in desalination system uses some of the electricity produced to create clean drinking water, and the rest of the electricity is fed back to shore and added to the grid. But the main disadvantages of desalinization are that it generates a lot of waste. In all these technological advancements the energy demand has been met with a renewable source such as solar or tidal energy, but the waste is pushed back into the ocean and in long term it will affect the salt balance. If these projects are commercialized, the amount of salt being dumped back into the ocean could cause disruptions in the ocean currents. The ecosystems will also be affected as aquatic life also has a threshold of salt water balance, beyond which it cannot survive.

Opinions/Viewpoints

A good alternative to this would be to make use of the chemicals present in the waste. Desalination waste generally comprises of sodium and magnesium salts. Apart from majorly contributing to production of Common Salt and Rock salt, both of these can be used to produce Caustic soda (NaOH) and Magnesium Hydroxide. The salt from ocean can also be used to produce Hydrochloric acid. All these chemicals are useful process chemicals in major industries. The only setback is the equipment cost (ion exchange resins, electrostatic precipitation equipment, etc.) and the electricity demand. The energy gap for desalination has already been bridged by both The Pipe and CPWEP. The only issue that remains is equipment cost. Although the initial investment seems high, the companies can profit off of the products that are obtained, making this not just a viable but sustainable option.

In another example, a new prototype that can condense water from air, called WarkaWater was designed in 2012 by the firm Architecture and Vision. WarkaWater is a 9 m tall structure, made of materials such as bamboo and rattan. It weighs 60kg and is composed of 5 sections, assembled and installed from top down and it can be lifted and fixed to the ground by 4 men. A special fabric hanging inside is capable to collect potable water from the air by condensation and at the base there is a container. The special type of fabric that picks up the water with great efficiency is the significant technological innovation of this tool. The structures, made of bio-degradable materials are easy to clean and can be erected without mechanical tools in less than a week. (Doğuş Bodamyalızade & Halil Zafer Alibaba, 2018) This is to supply water to a village where villagers come to the structure and collect water manually. When it is manufactured commercially accessibility will be a major challenge, as energy will be spent to transport the water collected to nearby areas. The second and more important challenge would be deforestation as this uses large amounts of bamboo wood.The world’s largest fog harvester uses giant mesh fences to trap dense fog in the Moroccan desert and turn it into clean, fresh water. It has an area of 600 square meters and produces 17 gallons of clean, safe drinking water per square yard of net. Efforts can be made towards delivering this water to the community in and around, in a sustainable way. This technology has a lot of potential if it can be commercialized, especially in humid regions of the world. (Dodson, L.L Bargach, J. 2015)

Opinions/Viewpoints

The WarkaWater project can collaborate with this innovation to make their structure easy to commercialize. They use bamboo wood because it retains water, and the fog harvester uses an alternative material to trap water. Their technology combined with the structural advantages put forth by WarkaWater project might give the sustainable solution that the world needs.

Food Sustainability

Agriculture and food industry is the largest contributor to global warming. As a chemical engineer this issue can be tackled in two ways: One is to ensure sustainable agricultural practices and the other is to ensure proper use of agricultural waste that does end up getting generated.

One example for sustainable agricultural practices was put forth by Perfecto and Vandermeer, who predicted that the existing “forest transition model” which was used for implementing agricultural practices was too theoretical and optimistic. They stated an alternative model and gave suggestions on steps which can be followed. From their work, we can easily understand the environmental impacts caused by wrong agricultural practices. (Perfecto and Vandermeer, 2010) Small scale farmers already adopt precision farming since they have few or no external inputs, use locally and naturally available materials, and generate agroecosystems that are more diverse and resistant to stress than capital driven farming. (Cornia GA, 1985) Their major solution was to encourage the upcoming small scale farmers. This is not something that large scale food companies would allow.

Opinions/Viewpoints

Simple steps such as crop rotation, drip irrigation method and use of natural fertilizers can come a long way in not just conserving the land but also in saving water, food and other important resources. Proper policy changes and regulations can force even large scale companies to follow such agricultural practices. This will also benefit them as their cost of inputs come down as well. If steps are taken to market the solutions put forth by Perfecto and Vandermeer, the model would be implemented without the large scale companies feeling threatened. . It is also not easy to monitor the agricultural practices of a cluster of small scale farmers. Whereas inspections can be conducted for large scale food industries easily.

As for sustainable use of food waste, Hamed Kazemi Shariat Panahi Et. Al. conducted a study of all the food waste produced in Iran and estimated generate 21.56 million ton per annum green wastes upon processing in the food industry.  He claims that every year about 5.4 billion liters of bioethanol can be produced by establishing second generation ethanol plants next to the food processing sectors. Seventy-seven-percent of this amount of bioethanol can easily support 5% ethanol (E5) policy to phase out the consumption of 4.2 billion liters methyl tert-butyl ether (MTBE) for raising the octane number of gasoline in the country. With policy changes, this can also prevent its dependence on fossil fuels, thus reducing air pollution (Hamed Kazemi Shariat Panahi Et. Al. 2019).

Opinions/Viewpoints

The problem which might occur, if this was to be commercialized, is that different types of food waste produces different quantities of bio ethanol. Therefore, proper cost analysis needs to be done regarding the type of feedstock they are extracting bio ethanol from, to determine if it is viable on large scale. If a major percentage of their produce is food wastes that do not produce a lot of fuel then the energy spent to burn the waste vs energy obtained from it tips to the opposite side.

Renewable Energy sources

The world is largely dependent on fossil fuels despite research into various renewable energy sources. Although nuclear energy is a viable clean energy source it cannot be considered as a long term solution, as the waste it generates requires a lot of treatment. Furthermore, the fuel is also less in amount. India implemented a three stage nuclear reactor programme to make efficient use of the available fuel. Thorium is particularly attractive for India, as it has only around 1–2% of the global uranium reserves, but one of the largest shares of global thorium reserves at about 25% of the world’s known thorium reserves. However, thorium is more difficult to use than uranium as a fuel because it requires breeding, and it is not cost effective. (Bucher 2009)

Fig.2.1. World Energy Consumption by Sources

Kalpakkam is the only city in the world which has successfully implemented this three stage nuclear reactor programme. The first stage is MAPS (Madras Atomic Power Station) which is a Heavy Water reactor. It uses Natural Uranium to generate electricity and produces Plutonium as waste. Plutonium goes into second stage which is PFBR (Prototype Fast Breeder Reactor) from which electricity is generated and Uranium 233 is produced as waste. This is fed into KAMINI (Kalpakkam mini reactor) which is a Thorium based reactor, to produce electricity. This greatly reduces the nuclear “Waste” produced, and gives thrice the amount of electricity with low fuel. (Usha .S et. al., 2006)

Fig.2.2. Three Stage Nuclear Power Programme

Opinions/Viewpoints

This is a viable project that can be implemented globally. Nuclear energy cannot be a long term solution for sustainable energy source, but it can help till the transition period, where we move from short term solutions to long term solutions to meet the global energy demand.

Among biomass to energy conversion algae is probably the best candidate to become a biomass fuel source of the future because it does not need freshwater, can grow in salty water, and does not require significant land to compete with land use for food. It also has a high volume to weight ratio which is volume of fuel produced to weight of biomass. Biomass to fuel conversion can be done through pyrolysis or chemical conversion (Aly Eldeen et al., 2010) Cell lysis of microalgae has high potential as it is clean and doesn’t produce carbondioxide, since there is no incineration. But the mechanical methods to break the cells involved a lot of power, and doesn’t seem viable. Chemical methods of cell lysis are still being explored.

Opinions/Viewpoints

There is a lot of potential as a chemical engineer in this area. Challenges in this field includes studying the reaction kinetics of each chemical lysis method. So far microalgae culture and lysis are performed in large tanks which are nothing but MFR (Mixed Flow Reactors). It is a known fact that the performance of a PFR is higher than that of an MFR for a fixed residence time, so studies can also be done to monitor the disruption rate in a PFR (Plug Flow Reactor) model. The third potential for chemical engineers in this field is to study the synergetic effect of two chemicals (P.J.Hetherington 1971)

Conclusions

In all the above mentioned techniques the contribution of a chemical engineer is vast. However it is important for us to work together with people from all fronts, such as large scale companies as well as small scale algae cultivators, if we are to come up with sustainable solutions for these problems. There are a million research ideas being put forth every year by chemical engineers but nearly all of them remain as ideas and never get implemented. This wasn’t an issue until we brought the planet to the brink of mass extinction, and now these ideas hold a lot of potential. Governments and Private companies need to spend funds and work on commercializing them, because in another five to ten years our conventional methods will become obsolete. Chemical Engineers themselves must implement systems thinking while putting forth a research idea, or building a prototype. They must have an idea about the challenges they might face, and work on mitigating it. We need to find interdisciplinary solutions to address this problem.

References

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