Introduction to natural gas.

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Bangabandhu Sheikh Mujibur Rahman Science and
Technology University, Gopalganj-8100
Assignment On
Natural Gas
Course Code:CHE409
Course Title: Industrial Chemistry-1
Submitted By Submitted To
Name: MD Khalid Masum
Student ID: 17CHE071
Year: 4th
Semester: 1st
Session: 2017-18
Department of Chemistry
BSMRSTU.
Name: Md. Matiar Rahman
Assistant professor.
Department of Chemistry
BSMRSTU.
Date of Submission: 18 July,2022

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INDEX
SL. NO. CONTENT PAGE NO.
01 The origins of natural gas 03
02 Composition of Natural Gas 04
03 Purification of Natural Gas 05
04 Production of hydrogen 06
05 Production of Nitrogen 07
06 Production of Carbon Dioxide 07
07 Production of Urea 08
08 References 10

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 The origins of natural gas
Like oil, natural gas is a product of decomposed organic matter,
typically from ancient marine microorganisms, deposited over
the past 550 million years.
This organic material mixed with mud, silt, and sand on the sea
floor, gradually becoming buried over time. Sealed off in an
oxygen-free environment and exposed to increasing amounts
of heat and pressure, the organic matter underwent a thermal
breakdown process that converted it into hydrocarbons.
The lightest of these hydrocarbons exist in the gaseous state
under normal conditions and are known collectively as natural
gas. In its pure form, natural gas is a colorless, odorless gas
composed primarily of methane. Methane, the simplest and
lightest hydrocarbon, is a highly flammable compound
consisting of one carbon atom surrounded by four hydrogen
atoms (chemical formula: CH4).
Once natural gas forms, its fate depends on two critical
characteristics of the surrounding rock: porosity and
permeability. Porosity refers to the amount of empty space
contained within the grains of a rock. Highly porous rocks, such
as sandstones, typically have porosities of 5 percent to 25
percent, giving them large amounts of space to store fluids
such as oil, water, and gas. Permeability is a measure of the
degree to which the pore spaces in a rock are interconnected.
A highly permeable rock will permit gas and liquids to flow

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easily through the rock, while a low-permeability rock will not
allow fluids to pass through.
After natural gas forms, it will tend to rise towards the surface
through pore spaces in the rock because of its low density
compared to the surrounding rock. Most of the natural gas
deposits we find today occur where the gas happened to
migrate into a highly porous and permeable rock underneath an
impervious cap rock layer, thus becoming trapped before it
could reach the surface and escape into the atmosphere.
Composition of Natural Gas
The basic chemical composition of natural gas essentially
contains methane and ethane. Apart from that it also contains
propane, butane, oxygen, hydrogen, penance, and many other
gases in small composition. This combination of gases can be
categorized into these categories.
1.Hydrocarbon Content
The main natural gas chemical makeup comprises mainly
hydrocarbon components. These components mainly
occur in a gaseous form under normal atmospheric
conditions. The hydrocarbon component is ethane,
methane, propane, and butane. Their gaseous form is
mainly the result of high pressure in the altitudes where
natural gas is found.
2.Non-Hydrocarbon Content
Complementing the composition and properties of natural
gas hydrocarbon content is the non-hydrocarbon
component. These are mainly noble gases such as helium
and argon. Apart from that, natural gas also contains
nitrogen, hydrogen, and carbon dioxide.
Apart from that, there are some components in a very
minute amount that have got distinct thermal and physical

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properties. These properties are then used to produce
other products.
 Natural gas purification by heat pump assisted
MEA absorption process
Natural gas purification is a critical pretreatment process before
it can be injected into the pipeline delivery grid. Generally, Acid
impurities (i.e. CO2 and H2S) in natural gas can be removed by
MEA (monoethanolamine) absorption process. However,
excessive energy consumption is still the challenge for the
current absorption processes. In this work, a novel heat-pump
assisted absorption process is proposed. To recover the waste
condensation heat in desorption stage, the vapor distillate
stream is compressed to elevate the exergy rate, and then
coupled with the bottom stream. Meanwhile, the waste
pressure of distillate is recovered by an expander. The
simulation results indicated that the net energy input of the

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proposed absorption process could be saved to 7.2 MW, which
equaled to 17.5% of the conventional process. The energy
consumption of impurity removal (set CO2 as reference) for the
heat-pump assisted absorption process can be reduced to
1.78 MJ/kg CO2.
 Production of hydrogen
Hydrogen can be produced from diverse, domestic resources,
including fossil fuels, biomass, and water electrolysis with
electricity. The environmental impact and energy efficiency of
hydrogen depends on how it is produced. Several projects are
underway to decrease costs associated with hydrogen
production.
There are several ways to produce hydrogen:
 Natural Gas Reforming/Gasification: Synthesis gas—a
mixture of hydrogen, carbon monoxide, and a small amount
of carbon dioxide—is created by reacting natural gas with
high-temperature steam. The carbon monoxide is reacted
with water to produce additional hydrogen. This method is
the cheapest, most efficient, and most common. Natural gas
reforming using steam accounts for the majority of hydrogen
produced in the United States annually.
A synthesis gas can also be created by reacting coal or
biomass with high-temperature steam and oxygen in a
pressurized gasifier. This converts the coal or biomass into
gaseous components—a process called gasification. The
resulting synthesis gas contains hydrogen and carbon
monoxide, which is reacted with steam to separate the
hydrogen.
 Electrolysis: An electric current splits water into hydrogen
and oxygen. If the electricity is produced by renewable
sources, such as solar or wind, the resulting hydrogen will
be considered renewable as well, and has numerous

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emissions benefits. Power-to-hydrogen projects are taking
off, using excess renewable electricity, when available, to
make hydrogen through electrolysis.
 Renewable Liquid Reforming: Renewable liquid fuels,
such as ethanol, are reacted with high-temperature steam to
produce hydrogen near the point of end use.
 Fermentation: Biomass is converted into sugar-rich
feedstocks that can be fermented to produce hydrogen.
 How Nitrogen Is Obtained
Nitrogen is produced commercially almost exclusively from air,
most commonly by the fractional distillation of liquid air. In this
process, air is first cooled to a temperature below that of the
boiling points of its major components, a temperature
somewhat less than - 328°F (-200°C). The liquid air is then
allowed to warm up, allowing the lower-boiling-point nitrogen to
evaporate from the mixture first. Nitrogen gas escaping from
the liquid air is then captured, cooled, and then liquefied once
more.
This process produces a high-quality product that generally
contains less than 20 parts per million of oxygen. Both an
"oxygen-free" form of nitrogen (containing less than two parts
per million of oxygen) and an "ultra-pure" nitrogen (containing
less than 10 parts per million of argon) are also available
commercially.
 What process produces carbon dioxide?
All aerobic life: mammals, fish, insects, many bacteria…might
be easier to note the few anaerobes that do not produce CO2.
Combustion of carbon and carbon-containing material: Wood,
coal, oil, fuel gases.

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Decomposition of carbonates: limestone, marble, other rock,
shells
Oceans’ gas exchange: Henry’s Law, a kind of equilibrium
“decomposition” probably makes the most carbon dioxide that’s
found in the atmosphere.
Cement: Human powered decomposition of limestone
(calcination).
It’s worth noting that all the carbon on Earth has been here for
most of its age, just as has all the oxygen, nitrogen and the rest
of the 92 natural elements, as well as the rarely found liquid
compound, water.
 Production of Urea
Urea: Chemically urea is the di-amine of carbonic acid or
carbamide.
Methods of synthesis:
(i) From phosgene gas.
(ii) Commercial process→ from natural gas
Commercial production of urea

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Urea is produced commercially from natural gas. In this
process natural gas is combusted to form Carbon dioxide
(CO2). Again Ammonia (NH3) is prepared by Haher- Bosch
process. Then ammonium carbamate is prepared by the
reaction between Carbon dioxide and Ammonia. This is then
decomposed by heat to produce urea. A mixture of compressed
CO2 and ammonia at 240 barg is reacted to form ammonium
carbamate. This is an exothermic reaction, and heat is
recovered by a boiler which produces steam. The first reactor
acheives 78% conversion of the carbon dioxide to urea and the
liquid is then purified.
Use of urea
Urea is the world’s most commonly used nitrogen fertilizer and
indeed more urea is manufactured by mass than any other
organic chemical.
 Urea is very important fertilizer in agriculture.
 Plastic production: Urea is used to produce urea-
formaldehyde resin, which is a polymer containing chains and
is broadly used as plastic.

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References
 https://www.ucsusa.org/resources/how-natural-gas-
formed#:~:text=Like%20oil%2C%20natural%20gas%20is,
gradually%20becoming%20buried%20over%20time.
 https://www.vedantu.com/chemistry/composition-and-
properties-of-natural-gas
 https://www.sciencedirect.com/science/article/abs/pii/S030
6261917309170#:~:text=2.2.-
,Heat%20pump%20assisted%20MEA%20absorption,of%
20acid%20gases%20and%20vapor.
 https://afdc.energy.gov/fuels/hydrogen_production.html
 https://science.jrank.org/pages/4683/Nitrogen-How-
nitrogen-obtained.html
 https://qsstudy.com/production-of-urea/
THE END