N

2.  Catalyst used in petrochemical process
is poisoned by trace amounts of
nitrogenous materials are contained in
feedstock’s
 Some nitrogen compounds are also
corrosive.
 Natural gas with nitrogen contents
greater than 0.2 mol% requires treatment
in refineries for nitrogen removal.

3.  To determine bound nitrogen in process
feeds and may also be used to control
nitrogen compounds in finished products
 Prevent gum formation in finished
product.

4.  Most prominent nitrogen containing classes
in crude oil are pyridine, pyridine derivatives
and pyrrole derivatives, including porphyrins.
 Hetero-atoms that are identified were
amides, hydroxy-quinolines, pyrrole-
carboxylic acids, imidazoles, caffeines, etc.

7. ASTM D 5762 is one of the method in ASTM
to determine Nitrogen content in crude oil
 At high temperature nitrogen presents in a
natural gas is converted into nitric oxide
(NO). The NO contacts ozone and is
converted to excited nitrogen dioxide (NO2).
The light emitted as the excited NO2 decays
is detected by a photomultiplier tube and the
resulting signal is a measure of the nitrogen
contained in the sample.

8.  Nitrogen analysis begins with high temperature
oxidation of the entire sample.
 The sample is combusted with oxygen at a
temperature of 1050 ºC. The oxidation products
include CO2, H2O, NO, SO2, and various other
oxides.
 The combustion gases are routed through a
membrane drying system to remove moisture
and then to the nitrogen detector module for
quantification.

9.  NO is contacted with O3 (ozone), produced
by an onboard generator, to form NO2
(metastable nitrogen dioxide).

10.  Boat inlet system: Boats are made up from
platinum or quartz. Small piece of quartz wool is
fitted to boat to provide sample injection. It
should be cleaned by swapping inert gas.
 Chemiluminescence Detector: It is used to
measure light emitted from the reaction
between nitric oxide and ozone.
 Combustion Tube: It is made up of quartz. The
inlet end of the tube shall be large enough to
accept the sample and have side arms to
introduce oxygen and inert gas for cleaning.

11.  Drier tube: To remove water vapour which can be
done by using magnesium per-chlorate Mg
(ClO4)2 or membrane drying or chilled
dehumidifier assembly.
 Electric furnace: To maintain temperature for
pyrolysis of sample for conversion of nitrogen to
NO.
 Temperature controller: For safety purpose to
maintain temperature below 1100 ºC in single
zone tube but in case of two zone tube 1050 ºC
has to be maintain in each zone.
 Micro-syringe: Capacity of 5 or 10 µL to provide
sample.
 Ozone detector and Recorder: To supply ozone
to the detector reaction cell and to display signal.

15.  Prepare a test specimen in a gas vial. The nitrogen
concentration in the test specimen shall be less than the
concentration of the highest standard used in calibration and
greater than 3 mg nitrogen/L.
 Record the volume of the test specimen.
 Sample is placed in a boat for measurements of
chemiluminescence response. Combustion of sample is taking
place in tube for conversion of N to NO and NO2.
 Check the complete combustion of sample and if some coke or
soot present allow some residence time and decrease the boat
introduction rate.

16. Measure each test sample three times and calculate the
average chemiluminescence response.

17. The concentration of nitrogen in the
crude oil is a measure of the
presence of nitrogen containing
compounds