Chemical engineers play an important role in environmental protection through various achievements. They develop processes to reduce pollution from automobiles through catalytic converters and cleaner-burning fuels. They also design systems for industries to capture air pollutants before emission and convert them to safer materials. Additionally, chemical engineers treat water through multi-stage processes to purify drinking water and wastewater for safe disposal or reuse. They further aid the environment by creating methods to recycle materials like aluminum, paper and plastics.

1. Role of a Chemical Engineer-
Environment
Mr. S. Dillwyn M. Tech.
Assistant professor
Department of Food Technology,
Hindusthan College of Engineering & Technology,
Coimbatore.

2. Who is a chemical engineer?
• Chemical engineering, deals with the application of chemistry and
other natural sciences to manufacturing processes.
• It focuses on using the safest and most efficient ways to make
products.
• Chemical engineering, may be applied to any product that
involves chemicals or chemical reactions, including food,
medicine, and cosmetics.
• A chemical engineer is an engineer who focuses on making
industrial and consumer products through chemical methods.
• Chemical engineers help plan the composition of the product
itself, as well as the overall manufacturing processes and
industrial equipment.

3. What does a chemical engineer do?
• Chemical engineers plan the manufacture of products through chemical techniques.
• They decide how to make the process safe, which reaction pathway to use, how to purify the
product, how to reduce, treat, and dispose of any by-products, what to do with unreacted raw
materials, and how to make the process cost and energy-efficient.
• They also develop new and improved chemical manufacturing processes.
• Some design and evaluate equipment and plan its layout to optimize processes and comply with
regulations.
• They design the order or manufacturing steps, and perform tests to monitor conditions
throughout the process.
• They may also design measuring and monitoring equipment for chemical plants. Some chemical
engineers specialize in certain processes or industries, such as nanotechnology or making plastics.
• They often work with other types of engineers, such as mechanical engineers, to create and
optimize industrial systems.
• Chemical engineers are helping address the energy crisis by creating fuel and electricity.
• Even when working on more consumer products they develop manufacturing processes that
require less energy.
• They also help make them as environmentally safe as possible, and eliminate as much waste as
they can.
• they decide on the safest way to treat and dispose of waste from by-products.

4. • Chemical engineers meet environmental challenges.
• Their unique expertise enables them to develop advanced
technologies, monitoring devices, modelling techniques, and
operating strategies that reduce the volume and toxicity of pollutants
allowed to enter the air, waterways, and soil.
• Significantly reduce the negative environmental impact of industrial
facilities, power plants, and transportation vehicles; and
• Also allow greater reuse of post-consumer and post-industrial waste
streams.
What is the role of a chemical engineer in
environment?

5. Achievements in the Environment
• Chemical engineers have always been there in the protection of
environmental.
• With a unique perspective with one leg on either side of both
science and engineering, they work in teams with other
professionals.
• By designing complex solutions to our vexing environmental
challenges, chemical engineers are striving to save the world we
live in.
• One success is the conversion of the sulphur oxides in power
plant gases into gypsum for use in wallboard.
• The removal of trace contaminants from drinking water by
reverse osmosis is another.

6. Cont..
1. Cars and the environment
2. Green manufacturing
3. Clean water
4. Recycle and reuse

7. 1. Cars and the environment
We can breathe more easily thanks to the contributions of chemical engineers.
By designing more efficient engines that produce fewer hazardous pollutants, they have
helped reduce the environmental impact of gasoline- and diesel-powered cars, buses, and
trucks.
a) Clearing the air
Compressed natural gas, is one product chemical engineers are working on to reduce the air
pollution generated by fossil fuel-burning vehicles.
Cars, trucks, and buses are essential for transportation and freight delivery around the world.
However, the exhaust from the gasoline- and diesel-powered engines required to propel these
vehicles has been a major cause of air pollution.
Chemical engineers, working with scientists and other engineers, have helped to develop
ways to cost effectively reduce the amount of pollution produced by petroleum-derived, fuel-
burning engines.
Key developments include:
• Improved engines with more efficient fuel- and air-management systems,
• Catalytic devices that destroy pollutants found in exhaust tailpipes, and
• Advanced petroleum-refining techniques that produce cleaner-burning fuels.

8. b) Catalytic converters
• The catalytic converter is considered one of the most important contributions to the
field of air-pollution control.
• It is now a standard feature on vehicles everywhere.
• It destroys the three main pollutants found in engine exhaust.
• The converter consists of a porous honeycomb ceramic base material coated
with a precious metal catalyst.
• The honeycomb structure provides high catalyst surface area, which maximizes
the contact between the catalysts and the pollutants in the hot exhaust gases.
When this novel structure was first invented, it featured two distinct chemical
engineering advantages:
1. It maximized the amount of catalyst-coated surface area to which the engine
exhaust may be exposed, and
2. It minimized the amount of expensive precious-metal catalyst required.
To recognize how important catalytic converters are in environmental protection,
President George W. Bush awarded the inventors of the catalytic converter, the
chemical engineer John Mooney and the chemist Carl Keith, with the 2002 National
Medal of Technology, the highest honour given for innovation in the United States.

9. c) Cleaner-burning fuels
• It is Another way chemical engineers help reduce automotive air
pollution is through advanced petroleum-refining techniques.
• One example is hydrotreatment, which uses hydrogen gas and a
catalyst to produce gasoline and diesel fuel with significantly
lower levels of sulphur and lead.
• These techniques have made it possible to produce reformulated
fuels that function as effectively as earlier leaded fuels, while
releasing fewer pollutants.

10. 2. Green manufacturing
Smokestacks, which were once the stereotypical image of factories and power plants, it is
no longer black smoke into the air.
Because of innovations by chemical engineers, industrial facilities now capture and
neutralize air pollutants before they can be discharged into the environment.
a) Blue skies ahead
Pollution-control systems developed by chemical engineers generate clean stack gas
containing steam instead of the smoky flue gases produced by power plant stacks, as
shown in this artist’s rendering.
Chemical engineers have helped provide new technologies to enable electric power plants
and industrial facilities to significantly reduce such harmful airborne emissions as:
• Sulphur dioxide (SO2),
• Nitrogen oxides (collectively called NOx),
• Mercury, and
• Unburned hydrocarbons.

11. b) Reducing industrial air pollution
• Sulphur dioxide and Nitrogen oxides react with water to create acid gases, which in
turn lead to acid rain.
• Acid rain, damages cars and buildings, kills trees, destroys lakes and streams, and
leads to respiratory and other health problems.
• Chemical engineers developed flue gas desulfurization (FGD), now a widely used
method of reducing acid gases in smokestacks.
• FGD works by using a wet scrubber spray tower in the flue or smokestack.
During operation, acid gases are converted to neutral salts and other solid by-
products, which are then removed.
• In case of Solutions to NOx emissions include selective catalytic reduction (SCR)
systems that convert NOx emissions to harmless nitrogen gas and water.
• Through the inventiveness of chemical engineers, wet scrubbers, SCR systems, and
other pollution-control technologies have significantly reduced the amount of SO2,
NOx, and other harmful emissions being released into the atmosphere.
• Specifically, the U.S. electric power industry has reduced SO2 emissions in the United
States by more than 5.5 million tons per year since 1990,
• Reduced NOx emissions by about 3 million tons per year since 1990, and
• Reduced acid rain deposition in the United States and Canada.

12. c) Cleaner coal use
• Coal remains the cheapest and most plentiful of all the fossil
fuels. However, it is also the most polluting.
• Chemical engineers have worked to perfect coal gasification, a
method to generate electricity and produce fuels from coal with
significantly less environmental impact.
• Now because if this utilities can burn clean synthetic gas made
from coal and have considerably fewer emissions than with
traditional pulverized coal combustion.

13. 3. Clean water
Clean water, which is essential to human health, is also necessary for numerous manufacturing
processes.
Many innovative methods of treating raw water to make it suitable for drinking or for use in
manufacturing have been developed by chemical engineers.
They also work on wastewater treatment to enhance safety and enable reuse.
a) Purifying drinking water, treating wastewater
With explosive population and industry growth, the need for cost-effective water-purification and
wastewater-treatment technologies has become more urgent than ever.
Chemical-engineering principles are used to remove harmful pollutants from both raw source water
and contaminated wastewater.
Specifically, chemical engineers have developed cost-effective methods to:
• Purify water from subsurface aquifers and surface sources, such as rivers and lakes, to produce potable
drinking water;
• Produce purified water that meets the increasingly strict requirements for industrial use; and
• Treat contaminated industrial and municipal wastewater and sewage to make them suitable either
for discharge to public waterways or for reuse.

14. b) Treating water
Modern-day treatment of raw water sources or contaminated wastewater
employs a wide array of physical, chemical, and biological techniques.
Chemical engineers refer to separating dangerous materials from good water
as a treatment train.
At various stages in the multistage treatment process, unwanted
constituents are separated using:
• Vacuum or pressure filtration,
• Centrifugation,
• Membrane-based separation,
• Distillation,
• Carbon-based and zeolite-based adsorption, and
• Advanced oxidation treatments.

15. c) Advanced oxidation
Worldwide, about 85% of childhood sickness and 65% of adult diseases are thought to be produced
by waterborne viruses, bacteria, and intestinal protozoa that cause diarrhoea and other potentially
life-threatening diseases.
The addition of oxidizing agents—chemical ions that accept electrons—has proven effective against
these microorganisms.
Today, a variety of advanced oxidation techniques kill such disease agents and disinfect water,
thanks to ongoing developments pioneered by the chemical-engineering community.
Historically, chlorine-based oxidation has been the most widely used, and it is very effective.
However, the transportation, storage, and use of chlorine (which is highly toxic) present significant
potential health and safety risks during water-treatment operations.
To address these concerns chemical engineers and others have developed a variety of alternative
oxidation treatments that are inherently safer, and in many cases more effective, than chlorination.
These include:
• Ultraviolet light,
• Hydrogen peroxide, and
• Ozone.
Each of these powerful oxidizing agents destroys unwanted organic contaminants and disinfects
the treated water without the risks associated with chlorine use.

16. 4. Recycle and reuse
One person's waste can become another person's treasure.
Recycling post-consumer paper, metal, and plastic reduces the environmental impact of acquiring more
raw materials.
Chemical engineers help make recycling possible.
In manufacturing, reusing industrial waste also offsets raw-material and energy requirements.
a) Turning waste into gold
In the 1970s, increasing environmental awareness renewed interest in recycling.
Today, about 32% of the average 750kg of waste produced annually per person in the United States is
recycled.
Significantly less municipal waste is being dumped in landfills.
Chemical engineers have played a key role in building the post-consumer and industrial waste
recycling industry.
Any successful recycling program must have three basic qualities:
• A suitable collection infrastructure,
• Appropriate reprocessing techniques to convert the waste into suitable end products, and
• A need or a market for the recycled products.

17. b) Recycling aluminium
Chemical engineers and metallurgists have worked together for decades to perfect metal recycling
techniques.
Sometimes it is easy. For example, stainless-steel cans can be recycled directly back into the steel with
little or no processing. Recycling aluminium, however, is more challenging.
The process for recycling aluminium was developed by chemical engineers in the 1960s, and aluminium
is now one of the most widely recycled materials.
Almost two-thirds of the aluminium cans in the United States are recycled, and 85% to 90% of the
aluminium in cars is recycled.
Before aluminium is reused, all paint, and labels are removed in a heated oven.
Cans are then chopped into small pieces and added to a molten aluminium bath along with
chemicals to remove any impurities. The remaining aluminium is formed into ingots for reuse by
fabricators.
The widespread use of recycled aluminium saves energy and reduces pollution, because mining and
processing raw bauxite ore to extract the aluminium it contains is very energy and waste intensive.
Specifically,
• Each one ton of aluminium cans produced from recycled cans saves five tons of bauxite;
• The reuse of aluminium cans reduces air pollution by 99% and energy consumption by 95% compared
with the production of virgin aluminium from bauxite; and
• The 54 billion cans that the United States recycled in 2006 saved the equivalent of 15 billion barrels of
crude oil.

18. C) Recycling paper
Paper is another post-consumer product that is now routinely recycled.
Because paper mills cannot use recycled paper as a direct substitute for
virgin tree pulp, chemical engineers have developed and optimized
processes that involve:
• Blending recycled paper and water to produce a pulp slurry,
• Removing all inks and other performance chemicals in the paper, and
• Filtering the slurry to remove solid impurities.
One of the biggest technical hurdles chemical engineers had to
overcome was the fact that recycled pulp has shorter fibres than virgin
pulp.
This characteristic makes the finished paper weaker and less attractive.
By combining virgin pulp (typically from wood chips) with recycled pulp,
chemical engineers solved the problem with a processing technique that
produces newsprint and other recycled-paper products that meet all
strength and requirements.

19. d) Recycling plastics
• Plastics are used in so many aspects of our daily lives, they
represent an ever-growing part of the nation's waste stream.
• In landfills they present a particular problem, as they do not
degrade readily.
• In addition, significant amounts of crude oil and energy are used in
producing plastics.
• We can now recycle most plastics into useful products.
• Because of chemical-engineering innovations, plastics are
separated by machine and reprocessed without significant
material breakdown, enabling reuse of many such plastic products
as pipe, toys, and decorations.
• This process not only protects our environment from plastic litter
but also helps the nation to become more energy independent.

20. THE END