RestekCorporation
(800) 356-1688
methylcyclopentene-1
benzene
2,3-dimethylheptane
p-xylene
m-xylene
1-methylnapthalene
tridecane
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run conditions.
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RestekCorporation
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quality control tests and specifications
for theRtx
®
-1PONA column. The
measuredvalues for retention (k),
efficiency (n) and stationaryphase
selectivity (RI) are controlled so that
each column exceeds the requirements
of theASTM andCGSBmethods.
These requirements include separating
several “critical pairs” of closely eluting
peaks of different hydrocarbon classes.
Figure 2
illustrates three of these
critical separations obtained from the
analysis of gasoline,without the need
for cryogeniccooling.
Detailedhydrocarbonanalysisprovides
agreat deal of information regarding the
chemical compositionof gasoline and
similar petroleumproducts. This
information is useful in evaluating the
performanceof a refineryprocess or to
calculate the chemical “value” of a
particular hydrocarbon stream for
chemical productionor gasoline
blending. It is possible to summarize the
detailed chromatographic report into a
hydrocarbon type analysis utilizing a
computer program and a table listing the
carbonnumber and typeof each
calibratedpeak.
Table 1
is an example
of aPONA report obtained from an
unleadedgasoline using aBASIC
programwritten for aprogrammable
integrator. It is alsopossible todevelop
correlations for other important
properties such as vapor pressure and
octanenumber from the compositional
analysis of gasoline andnaphtha
3
.A
100-meter column is also specified for
petrochemical analyses
4
requiring a
highdegreeof resolution,where
specialized stationaryphases or column
switching systems donot achieve the
desired separations.
TheRtx
®
-1PONA column is an
excellent choice for separationof
complexpetroleumproducts such as
gasoline andnaphtha. Each column is
specially tested to exact specifications,
meeting thedemanding separation and
retention criteria ofASTM andCGSB
procedures.WithHRGC, it is possible
to resolve and identifyhundreds of
individual hydrocarbons.This informa-
tion canbeuseful for hydrocarbon type
(PONA) analysis or for estimating
vapor pressure andoctanenumber.
1
N.G. Johanson,
ProposedASTMTestMethod for
Detailed Hydrocarbon Analysis, Draft 2,
ASTMCommittee D2.04.
2
Canadian General Standards Board,
Methods of
Testing Petroleum and Associated Products 3.0
,
MethodNo. 14.3-94 (Feb 94).
3
R.P. Walsh and J.V. Mortimer,
Hydrocarbon
Processing
, p.153 September 1971.
4
ASTMD5441 Standard TestMethod for the
Analysis ofMethyl Tert-Butyl Ether (MTBE) by
GasChromatography,
AnnualBookofStandards
,
Vol. 5.03
Table 1:
HydrocarbonTypeReport fromDetailedHydrocarbonAnalysis
C#
P (Wt%)
I (Wt%)
O (Wt%) N (Wt%)
A (Wt%)
X (Wt%)
2
0
0
0
0
0
3.48
3
0.07
0
0
0
0
0.23
4
0.24
0.2
0.83
0
0
0.21
5
1.8
8.77
8.76
0.12
0
0
6
1.84
4.93
4.21
1.88
0.64
0
7
2.14
4.31
2.93
3.95
2.66
0.01
8
2.42
4.24
0.7
3.85
5.31
0.06
9
1.72
3.86
0.36
3.19
5.27
0.15
10
0.88
2.61
0.04
0.62
4.72
0.36
11
0.48
0.47
0
0.17
1.63
0.12
12
0.43
0.61
0
0.02
0.56
0.29
13
0.3
0.34
0
0
0
0
Total
12.34
30.34
17.83
13.82
20.78
4.9
Resolutionof several critical pairs of hydrocarbons.
Figure 2
min. 60
min. 60
min. 60
