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| Preparation Method of Urea |
Preparation Method of Urea
Urea or Carbamide
Urea or Carbamide is the first synthesize by
Friedrich Wohler in 1828. And the urea is a good nitrogenous fertilizers for the
nitrogen source for plants. And due to slight basic in nature it is also used
to reduce the acidity of the soil by decaying action of the organic matter. On
commercial scale when ammonia reacts with carbon dioxide it forms urea. Such
reaction is as follow
2NH3 (g) + CO2 (g) è CO (NH2)2 (s) + H2O (I)
Industrial preparation or preparation of Urea
The following steps that are involved in preparation of urea is as
follow.
1 . Preparation
of carbon dioxide and hydrogen:
Carbon dioxide and hydrogen is obtained by passing mixture of methane gas and
steam over nickel as catalyst by heating. Such reaction is as follow
CH4 + 2H2O Ni/heatè CO2 + 4H2
2 .
Preparation of Ammonia: The hydrogen gas
produced in first step is treated with nitrogen gas at about 500°C heat and 200
atmospheric pressure to produce ammonia. That is
3 . Preparation
of Ammonium Carbamate: Ammonia produced in second step is now
treated with carbon dioxide to form ammonium Carbamate (NH2COONH4). Such
reaction is as follow
2NH3 +
CO2 è
NH2COONH4
4 . Preparation of urea: Ammonium carbonate which is
produced in last now is dehydrated by heating to obtain urea. Such reaction is
as follow.
Concentration of Urea
The urea is obtained is
then concentrated by evaporating water by heating. The molten urea is obtained
by heating the sprayed in a cooled tower. As result the urea drops solidify as
small prills. This process is called
prilling. After this urea prills are
filled in bags and then sent to market foe selling.
How the petroleum originated in the earth crust? What are the different fractions obtained from the petroleum and also describe the utilization of these fractions?
The petroleum industry
The word petroleum has been
derived from two Latin word Petra means
rocks and Oleum means oil. Thus it means rocks oil. It is a
black or brownish black viscous liquid found under the earth. It is a mixture
of thousands of organic compounds like gases, liquids and solids.
Uses of petroleum
for different uses these
compounds are separated in fractions in oil refiners. The petroleum is very
important and plays a vital role in today’s world as it fulfils almost all the
requirements of energy of human beings in today’s world directly. There are
many industries that depends upon petroleum industry. Such as Plastic industry
is all based upon the material which is obtained from petroleum.
Origin of petroleum
It is generally believed
that petroleum is obtained from remain of microscopic plants and animals which
lived in seas millions of years ago. After geographical changes these plants
and some extend to animals were buried under the earth and the chemical effects
of pressure, temperature, heat and bacteria converts these buried animals and
plants into the organic compounds petroleum.
Mining of petroleum
The crude oil or petroleum
is formed is trapped in rocks under the earth’s crust which is taken out by the
tubes just like a water in a tube well but unlike a water petroleum is not so
abundant therefore is found in some special areas at more depth than water. The
most common method of obtaining the petroleum is extracting it from oil wells
found in oil fields. After the well has been found various methods are used to
recover the petroleum. Such is as follow
1 . Primary recovery method: In this method underground
pressures are used to extract crude oil or petroleum. In this way about 20% of
total crude oil presents is extracted.
2 . Secondary recovery
method: When primary method fails to recover the petroleum then secondary
method is used to recover petroleum. And about 5% to 10% of oil to surface is
extracted by this method.
3 . Tertiary recovery
method: When both primary and secondary method fails to recover petroleum then
this tertiary method is used to reduce the viscosity of the oil in order to
bring more oil to the surface.
Important fractions or utilization of petroleum
Petroleum is a useless mixture of very useful substances
which is use on various ways. After extraction crude oil is brought to an oil
refinery and the refinery process utilizes the distillation technique which separate
different fractions of petroleum. This process is carried out by the process of
fractional distillation where different components of a mixture is separated on
basis of boiling point difference. This process only consists of evaporation
and condensation. From this different fractions are collected in different
types of engines. And these fractions differ in number of carbon atoms per
molecule as the number of carbon atoms in a molecule is increased. The boiling
point, melting point and density also increase of a substance and even the
fractions that contain more than 40 atoms may be solid, semi – solid or waxy
solids.
