1. Date of Submission:
09/24/2015
Mr. Kennedy Jachike Patrick
Country: Nigeria. DOB: 02/04/1988.
Status: Single. Occupation: Industrial Chemist.
Type of Organization: FMCG (Food and Beverage
production)
Contact Information
Email Address: patrickkennedyjachike@gmail.com

2. CONTENT
Introduction
Scrubbing and Recycling
scrubbing in Irreversible Reactions
Usefulness of the products of greenhouse
scrubbing.
Separating the gas mixtures on emission
A scrubbing policy for industries emitting
greenhouse gas.
Conclusion

3. INTRODUCTION
Climate change is a change in weather patterns
resulting mainly from biotic processes and solar
radiation received by earth. Climate change is
caused by ozone layer depletion and increased
greenhouse gas level, it generally comprises of
global warming ( surface temperature increases) and
every other thing that increasing greenhouse gas
level will effect.
The greenhouse gas effect is simply a process by
which thermal radiation from a planetary surface is
absorbed by atmospheric greenhouse gases (water
vapour, carbon di oxide, hydrogen sulphide,
methane, nitrous oxide and ozone), and is re-
radiated in all directions. Thus, with increased ozone
layer depletion and greenhouse gas emission by
human activities, climate change becomes a daring
challenge to humans and living things at large.

4. The effect of green house gas emission on earth.
Increased emissions of greenhouse
gases (GHGs) is the key contributor to global
warming and climate change generally.
When solar radiation passes into the Earth’s
atmosphere, most is absorbed
by the Earth and some is reradiated back into the
atmosphere. GHGs trap the heat, keep it from
passing through the atmosphere to space, thus
causing the lower atmosphere to warm.
Some GHGs occur naturally in the atmosphere, while
others are emitting strictly by human activity.
CO2 is emitted by combustion of fossil fuels (oil,
natural gas, and coal), solid waste, biomass (e.g.,

5. wood products), and by industrial processes (e.g.,
cement kilns). Also, CO2 can be removed from the
atmosphere when it is absorbed by plants as part of
the biological carbon cycle (but this might not be to
reduce CO2 level in the atmosphere to a
considerable level with the increasing
industrialization of our world today). CH4 is emitted
during the production and transport of fossil fuels,
and can be emitted through livestock and other
agricultural practices and by the decay of landfill
wastes. N2O is emitted by fossil fuel and solid waste
combustion, and during agricultural and industrial
activities, Hydrofluorocarbons, sulfur hexafluoride,
and perfluorocarbons are emitted from a wide range
of industrial processes, including during their
production as well as their use in refrigeration and
air conditioning, during semiconductor
manufacturing, and as substitutes for ozone
depleting substances (ODCs).
Since it’s glaringly evident that climate change is
man-made, it's therefore logical to say that it can
only be unmade by man. Owing to this, I propose
scrubbing and recycling as the most efficient way to
end climate change.

6. SCRUBBING AND RECYCLING
Greenhouse gas in the atmosphere comprise about
90% of the factors leading to climate change, hence
a reduction of the greenhouse gas level in the
atmosphere will be a perfect way to deal with
climate change.
Scrubbing which is an operation in which a gas or gas
mixture is contacted with a liquid for the purpose of
dissolving the gas mixture or some of its
components and to provide a solution of them in the
liquid, is the best way to reduce the emission of
greenhouse gases into the atmosphere. In this
process, there is a mass transfer of the gas from the
gas phase to the liquid phase and the gas so
transferred is absorbed by the liquid.
Types of Absorption Processes
There are two types of absorption processes;
physical absorption and chemical absorption,

7. depending on whether there is any chemical
reaction between the solute(gas) and the solvent
(absorbent). For instance; when water and
hydrocarbon oils are used as absorbents , no
significant chemical reaction occur between the
absorbent and the solute, and the process is
commonly referred to as physical absorption.
When aqueous sodium hydroxide (a strong base) is
used as the absorbent to dissolve an acid gas,
absorption is accompanied by a rapid and
irreversible neutralization reaction in the liquid
phase and the process is referred to as chemical
absorption or reactive absorption.
2NaOH(aq) + CO2(s) ----> Na2CO3(aq) + H2O(l)
More complex examples of chemical absorption are
processes for absorbing and recycling CO2 and every
one of the other gases that constitute the
greenhouse gases with aqueous solution of
monoethanolamine (MEA), diethanolamine (DEA),
diethyleneglycol (DEG)etc, where a reversible
chemical reaction takes place in the liquid phase.
Cold solutions of these organic compounds bind
CO2, but the binding is reversed at higher
temperatures.

8. CO2 + 2HOCH2CH2NH2<------> HOCH2CH2NH3
+
+
HOCH2CH2NH(CO2
-)
This reversible process can thus be used to absorb
and recycle these greenhouse gases.
A diagram illustrating CO2 absorbtion
The above diagram illustrates a process in which
carbon dioxide is absorbed from a gas stream
directed into a liquid, typically an amine(e.g MEA).
The gas stream, with most of the carbon dioxide
removed, is then emitted to the atmosphere. The
liquid is processed by cooling to remove the carbon

9. dioxide, which is then compressed for storage. The
resulting carbon-dioxide-free liquid is used again for
absorption and the process continues. This
technique is fairly widely used in a range of
applications.
The absorption process is most commonly applied to
post-combustion capture and the absorbents are
liquid solvents.
In post-combustion systems, the flue gas needs to be
cooled and impurities removed so that the solvent
can efficiently absorb the CO2.
The flue gases containing CO2 and N2 are then fed
into a tower called the absorber tower. The flue gas
comes into the bottom of the tower while the
solvent is fed into the top of the
tower. There is packing material in the tower, and
the flue gas flows up through the packing,
making contact with the solvent as it falls down. The
CO2 is absorbed by the solvent as the flue gas rises
so that the gas that comes out of the top of the
tower contains very little CO2.
The solvent, with dissolved CO2, is then removed
from the chamber. The N2 is released as it is not
absorbed in the solvent. The recovery of CO2 from
the solvent is called desorption. The usual process

10. for recovery of CO2 from the solvent is temperature
change .
Other methods include pressure changes and the
use of membranes with solvents (see membranes).
The loaded solvent passes into another tower where
is it heated. As it falls down through the tower, the
CO2 is desorpted (released) from the rich solvent at
temperatures of 100 o + C.
Water-saturated CO2 flows from the top of the
tower into a tank which removes excess water. The
solvent is recovered to absorb more CO2.
As all the solvent must be heated, not just the CO2,
solvent capture of CO2 results in significant
reductions in energy efficiency. Heat is necessary to
regenerate the solvent and recover the CO2. Energy
is also required to operate pumps and fans and to
compress the CO2.
SCRUBBING IN IRREVERSIBLE REACTIONS
Whereas the above process absorbs the gases in a
revesible reaction(which makes recycling easier),
some metallic oxides and hydroxides such as calcium
oxide(CaO), sodium hydoroxide(NaOH), and lithium
hydroxide (LiOH) can be used to absorb the gases in

11. an irreversible reaction. However, CO2 can still be
recovered from the irreversible reaction using either
of the metallic oxides or hydroxides mentioned
above. For instance;
2NaOH(aq) + CO2(g) -----> Na2CO3(aq) + H2O(l)
Causticization:
Na2CO3(aq) +Ca(OH)2(s) ----> 2NaOH(aq) +CaCO3(s)
∆H° = -5.3KJ/Mol.
The Calcium carbonate(CaCO3) precipitated in the
above reaction is subsequently filteed from solution
and thermally decomposed to produce gaseous CO2.
CaCO3(s) -----> CaO(s) + CO2(g)
In the scrubbing process using NaOH or other
metallic hydroxides, the CO2 is absorbed into
solution, transferred to lime via a process called
causticization and released in a kiln, mainly an
oxygen fired kiln, and the end result is a
concentrated stream of CO2 ready for storage or use
in fuels. An alternative to this thermo-chemical
process is an electrical one in which a nominal

12. voltage is applied across the carbonate solution to
release the CO2. Concentrated solar plates could be
a perfect source of electrical energy.
SEPARATING THE GAS MIXTURES ON EMISSION
The industries emitting these gases might not just
emit one gas but a mixture of it, hence the need to
separate in a situation like this.
However, advanced separation techniques will not
be necessary in this process as the gas mixture will
simply be passed through the different absorbents
required to selectively react with each constituent of
the gas mixture. For gases like carbon mono oxide
that can easily be converted to carbon di oxide
through aeration, such aeration processes will be
employed for the conversion before absorption. The
engineering would be such that from the chimney or
outlet through which these gases are meant to be
released to the atmosphere, a construction is made
to channel these gases to the scrubbing chamber,
whirling them through the absorbents already stored
in different compartments for absorption, and from
there they are conveyed further for other recycling
processes, like a condenser for the cold state

13. reversible reaction requiring monoethanolamine to
give back carbon di oxide (CO2).
USEFULNESS OF THE PRODUCTS OF GREENHOUSE
SCRUBBING
Interestingly, all the products of the CO2 absorption
process involving the use of metallic oxides and
hydroxides have important applications and uses.
In the absorption process involving NaOH and CO2
for instance, should one decide not to proceed to
recovering CO2, Na2CO3 which is a product of the
absorption process has the following uses:
(1). In the manufacture of glass - ordinary glass is
made by fusing together Na2 CO3 , CaCO3 , SiO2 and a
little carbon (as a reducing agent).
(2). In domestic water softening process, Na2 CO 3
precipitates the Ca2+
ions which cause hardness in
water.
(3). In the manufacture of water glass.
(4). In the manufacture of NaOH, sodium silicate(VI)
and borax.
(5). In the manufacture of soap and paper.

14. (6). Used in standardizing acids for titrimetry analysis
in the laboratory.
Should one decide to stop at causticization, CaCO3
which is a product of causticization has the
following uses:
1. In the manufacture of sodium carbonate,
quicklime, cement, glass and steel.
2. For neutralizing acids in acidic soils.
3. In the extraction of iron.
4. As building materials e.g cement etc.
5. In the manufacture of pigments, putty and paper.
After decomposition, calcium oxide (CaO) which is
obtained alongside Carbon di oxide(CO2) has the
following uses:
(1). In the manufacture of slaked lime, Ca(OH)2
(2). In the building industry for the preparation of
mortar and for the manufacture of cement.
(3). In the manufacture of calcium carbide.
(4). In smelting processes.

15. (5). In the manufacture of refractory furnace linings.
(6). In the manufacture of glass.
(7). For drying ammonia in the laboratory.
CO2 itself on recovery can be used thus:
Carbon dioxide is commonly used as a raw material
for production of various chemicals; as a working
material in fire extinguishing systems; for
carbonation of soft drinks; for
freezing of food products such as poultry, meats,
vegetables and fruit; for chilling of meats prior to
grinding; for refrigeration and maintenance of ideal
atmospheric conditions during transportation of
food products to
market; for enhancement of oil recovery from oil
wells; and for treatment of alkaline water.
Same level of usefulness applies to the products of
other greenhouse gas absorption processes.

16. A SCRUBBING POLICY FOR INDUSTRIES EMITTING
GREENHOUSE GAS
A world-wide policy mandating every industry
emitting these gases that constitute the greenhouse
gas to build a scrubbing system, or scrubbing and
recycling system to prevent the emission of these
gases in the atmosphere should be instituted.
The policy should also make the building of
greenhouse gas absorption system as described in
this proposal a compulsory prerequisite for
establishing any industry that will be emitting these
gases. A policy on these greenhouse gas absorption
techniques and there possible future modifications is
the solution to climate change in the world.
This policy will be beneficial both to the industries
and the society at large as it will help expand
economic strength of industries by either helping
them recycle these gases or by producing an entirely
new useful substance, all to growth and economic
advantage.

17. CONCLUSION
With the institution of the above proposed policy by
the government of every nation and it's subsequent
implementation by every industry, climate change
will soon become a thing of the past as the
greenhouse gas level emitted into the atmosphere
will significantly reduce.
For every of the greenhouse gases, there is an
absorbent with which they can be absorbed and thus
prevented from escaping into the atmosphere,
thereby causing climate change.