Adlard E.R. (ed.) Chromatography in the Petroleum Industry
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222
Chapter
8
~~~~~~~~ ~
Gas
Chromatograph:
Varian
Model
3410
Sulfur
Detector
Sieves
Inst..
Inc.
Model
350A
SCDbn
co(LgMI:
10mx0.53mm
1.5~
085
FSOT
(J&WScienttfic)
Column
Temperature:
0
min.
Q
W<
to
400%
Q
10.0
O/rnin
Carrier Gas:
Helium
Q
2
psig
(6.0
&hn.)
SPI
Injector: 100°C
-
400°C
@
2CFC/min.
FID:
400°C
Air
Q
40
psig.
Hi
Q
35
psig.
Makeup: Helium
Q
30
crr?hin.
Manual
Injection:
0.2pL
(Hamilton
#7001)
SCD
Response
dl
Total
Sulfur
=
28.5
mas&
0
4
8
li
:F
20
24
28
32
Y
in
Die
8
20828011
FID
Response
60
40
mv
21)
0
0
4
8
12
I6
20
24
28
32
Yiauiev
2082801
R
Fig.
8.1
1.
SCD
and
FID
chromatograms
of
a
low sulfur
diesel
fuel.
The chemiluminescence detector
223
Gas Chromatograph: Varian Model
3410
Sulfur Detector: Sievers
Inst.,
Inc. Model 350A SCDm
Column: 10mx0.53mm
1.w
DB5
FSOT
(Jaw
Scientific)
Column Temperature:
0
min.
Q
400C
to
4OOOC
Q
10.0
Ohin.
1
Carrier Gas: Helium
Q
2 psig
(6.0
cm3hin.)
SPI
Injector: 100C
-
400°C
Q
20"Chin.
FID: 400°C
Air
Q
40 psig.
H,
Q
35 psig.
i
Makeup: Helium
Q
30
cdhin.
I
Manual Injection:
0.2pL
(Hamilton
#7001)
SCD
Response
30
1
20
MV
10
0
4
a
12
16
20
24
28
32
36
Ylnulrr
?Oh27081
'0°
1
FID
Response
mV
50
-
0
4
S
12 16
20
24
28
32
35
Yinutea
20827088
Fig.
8.12.
SCD
and
FID
chromatograms
of
West Texas intermediate crude oil.
References
pp.
227-229
724
Chapter
8
1
Sulfur
Detector:
Seven
Inst..
Inc.
Model
350A
SCD"
jj
Column:
10mx0.53mm
1.5~
DB5
FSOT
(Jaw
Scientific)
1
I
Column
Temperature:
0 min.
Q
40%
to
400°C
Q
10.0 */min.
~!
Carrier Gas:
Helium
Q
2
psig
(6.0
cm)hin.)
~!
SPI
Iqector: 100C
-
400C
Q
MoChnin.
ij
FID:
400°C
Air
Q
40
psig.
I-$
Q
35
pslg.
,
Makeup: Helium
Q
30
crnhin.
'
Manual Injection:
0.2pL
(Hamilton Wool)
i
SCD
Response
75
1
al
-
u
5
511
-
Total
Sulfur
=
4.471
mg/L
mV
25
-
FID
Response
0
4
8
I2
16
20
24
28
22
36
Y
In
uts
s
20827098
Fig.
8.13.
SCD
and
FID chromatograms
of
Ordovician
crude
oil.
The chemiluminescence detector
3.
.I
2.
1-
0-7
225
Total Sulfur
=
204.8
maSlL
Gas Chromatograph: Varian Model 3410
Sulfur Detector: Sievers Inst.. Inc. Model
350A
SCDm
Column:
10m
x
0.53mm
1.5~
DB5
FSOT
(Jaw
Scientific)
Column Temperature:
0
min.
Q
4OoC to 4OOOC
Q
10.0
Ohin.
Carrier Gas: Helium
Q
2
psis
(6.0
CrrPMn.)
SPI
injector:
i0OC
-
400°C
Q
20"Chin.
FID:
400C
Air
Q
40 psig.
H,
Q
35
psig.
Makeup: Helium
Q
30
crrhtnin.
Manual Injection:
0.2pL
(Hamilton #7001)
SCD
Response
Feedstock to Hydrotreater Unit
'i
Total
Sulfur
5
1.813
maS/k
3-
.I
2-
1-
0
4
6
12
16
20
24
26
,'
ih
40
41
1.
Y
in
"1.
I
20621361
Product from Hydrotreater Unit
Fig
8.14.
SCD
chromatograms
of
gas
oil
before
and
after hydrotreating.
References
pp.
227-229
226
Chapter
8
tions.
As
previously noted, the SCD is susceptible to contamination and
loss
in
sensitivity due to
column
and septa bleed and this problem is particularly acute
in high temperature GC. The use of well-conditioned columns and low bleed
septa are required for high temperature
GC
with SCD detection. With these pre-
cautions, the SCD can be used for the simultaneous hydrocarbon and sulfur
compound boiling range distribution.
Figure
8.12
shows the
FID
and SCD chromatograms from the analysis
of
a West Texas Intermediate crude oil. The major sulfur components are di-
benzothiophene and its alkyl derivatives. There is also a relative large amount
FID
Response
Feedstock
to
Hydrotreater Unit
15
mY
lb
5
-.
0
4
8
12
16
23
24
28
32
36
40 44
Yinrtmm
20828068
Product
from
Hydrotreater Unit
25
1
ol
0
4
E
12
16
20
24
28
32
36
40
44
Ylnrtmm
20828088
Fig.
8.15.
FID
chromatograms
of
gas
oil
before
and
after hydrotreating.
The chemiluminescence detector
227
of higher molecular weight (bp
>
C30) sulfur compounds present in this sample
as indicated by the unresolved ‘‘hump” observed at the end of the chromato-
gram.
An even higher concentration of these high molecular weight sulfur com-
pounds can be seen in Fig.
8.13,
which shows the
FID
and SCD chromatograms
from an Ordovician Crude Oil. The total sulfur content of this sample was found
to be approximately three times than the West Texas crude and a large percent-
age of the sulfur compounds are higher molecular weight species.
The SCD can also be useful in monitoring refinery processes by measuring
the concentrations of sulfur compounds in feedstocks and resultant products. An
example
of
this is shown in Figs.
8.14
and
8.15
for the feedstock and product
of
a hydrotreating unit. The SCD chromatograms shown in Fig.
8.14
illustrate that
significant reduction in the concentrations of
sulfur
compounds is achieved by
this treatment, while the
FID
chromatograms, Fig.
8.15,
indicates that the major
hydrocarbon constituents are relative unchanged.
8.9 CONCLUSIONS
The high sensitivity, selectivity and linear response of the sulfur chemilumi-
nescence detector have made this instrument a valuable tool for the measure-
ment of sulfur compounds in petroleum and petrochemicals. The equimolar re-
sponse for different sulfur compounds and the absence of quenching of the re-
sponse due to co-elution
of
hydrocarbons permits determination of low ppb lev-
els
of
sulfur compounds in hydrocarbon matrices and determination of total sul-
fur content.
The SCD has also found applications in the measurement of sulfur com-
pounds for foods, flavor, and beverages, pesticides and other environmental
applications, detection
of
chemical warfare agents, quality control for pharma-
ceutics and basic chemicals and a host of other areas
[27-331.
8.10 ACKNOWLEDGMENTS
The author would like to thank Neil Johansen
of
Sievers Instruments for pro-
viding the chromatograms and his assistance in the preparation of the chapter.
8.11 REFERENCES
1
W.L
Orr
and
C.M. White, Geochemistry
of
Sulfur in Fossil
Fuels,
American Chemical Soci-
ety,
Washington DC
(1
990).
228
Chapter
8
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
ASTM Standard
D2622,
Annual Book
of
ASTM Standards,
Vol.
05.02,
ASTM Philadelphia,
PA
(1990).
ASTM Standard
D3246,
Annual Book
of
ASTM Standards,
Vol.
05.03,
ASTM Philadelphia,
PA
(1987).
ASTM Standard
D4045,
Annual Book
of
ASTM Standards, Vol.
05.03,
ASTM Philadelphia,
PA
(1
990).
S.
S.
Brody and
J.
E. Chaney, J. Gas Chromatogr.
4
(1966) 42.
S.
0.
Fanvell and C.
J.
Barinaga,
J.
Chromatogr. Sci.
24 (1986) 483.
M. Dressler, in: Selective Gas Chromatography Detectors, Elsevier, Amsterdam
(1986),
p.
133.
C. Bradley
and
D.
J.
Schiller, Anal. Chem.
58 (1986) 3017.
J. L. Buteyn and J. J. Kosman,
J.
Chromatgr. Sci.
28 (1990) 19.
T.R.
McManus, Anal. Chem.
63 (1991) 48R.
R.S. Hutte and J.D. Ray, in: Detectors
for
Capillary Chromatography, Wiley, New York
(1992),
p.
193.
R.C. Hall, J. Chromatogr. Sci.
12 (1974) 152.
R.C.
Hall, in: Detectors for Capillary Chromatography,
109.
P.C. Uden, Y. Young,
T.
Wang and
Z.
Cheng,
J.
Chromatogr.
486 (1989) 319.
P.C. Uden, in: Detectors for Capillary Chromatography, Wiley, New York
(1992),
p.
219
B.D. Quimby and J.J. Sullivan, Anal. Chem.
61 (1990) 1027.
R.L. Benner and D.H. Stedman, Anal. Chem.
61 (1989) 1268.
C.J. Halstead and B.A. Thrush, Proc.
R.
SOC. London
295 (1966) 363.
R.L. Benner, R.L. and D.H. Stedman, Environ. Sci. Technol.
24 (1990) 1592.
Operation and Service Manual Model
350B
Sulhr Chemiluminescence Detector, Sievers
Instruments, Inc.
(1990).
R.L. Shearer, D.L. O’Neal,
R.
Rios and M.D. Baker, J. Chromatogr. Sci.
28 (1990) 24.
H.V. Drushel and G.D. Dupre, Sulfur compounds in petroleum by GC/SCD: detector
evaluationioptimization and
BP/TR
correlations, presented at the
1991
Pittsburgh Conf-
erence.
ASTM
Committee
D-2
Proposed Standard Test Method
for
the Determination
of
Sulfur Com-
pounds in Petroleum Gases and Light Liquids by Gas Chromatography and Chemilumines-
cence Detection.
K.J. Bohler, A.J. McCormack and J.M. McCann, Simultaneous detection
of
aromatics, sulfur
and hydrocarbons in diesel fuels by gas chromatography, presented at American Chemical
Society Meeting
(1991).
R.L. Shearer, Anal. Chem.
18
(1992) 2192.
Operation and Service Manual Model
355
Sulfur Chemiluminescence Detector, Sievers In-
struments, Inc.
(1
993).
N.G. Johansen, R.S. Hutte and
M.F.
Legier, in: Monitoring Water in the
1990s:
Meeting New
Challenges ASTM STP
1102.
H.C. Chang and L.T. Taylor, Anal. Chem.
63 (1991) 490.
M.S.
Burmeister, C.J. Drummond, E.A. Pfister and D.W. Hysert,
J.
Am
SOC Brew. Chem.
50
(
1992) 53.
R.S. Hutte and R.E. Sievers, Selective detection
of
HD and
VX
using the
sulfur
chemilumi-
nescence detector, presented at
47th
Southwest Regional American Chemical Society Meeting
(
199
1
).
K.
MacNamara, Investigation
of
medium volatile sulfur compounds in whiskey, presented at
the Cognac Symposium
(1992).
The chemiluminescence detector
229
32
R.
Dominguez,
Jr.,
The determination
of
total sulfur in fuel, landfill and sewage digester gas
using
the
sulfur chemiluminescence detector, presented at American Chemical Society Meet-
ing (1992).
R.L.
Shearer,
E.B.
Poole and
J.B.
Nowalk,
J.
Chrornatogr. Sci. 31 (1993) 82.
33
This Page Intentionally Left Blank
E.R.
Adlard
(Ed.),
Chromatography
in
the Petroleum
Industry
Journal
of
Chromatography
Library
Series,
Vol.
56
0
1995
Elsevier Science B.V.
AU
rights
reserved
23
1
CHAPTER
9
Multi-column systems in gas
chromatography
H.
Mahler,
T.
Maurer
and
F.
Mueller
Siemens
AG,
AbtAUT35
CHR,
Postfach
21 12
62,
76187
Karlsruhe. Germany
9.1
INTRODUCTION
9.1.1
Limitations
of
single-column
systems
Unquestionably, most practical applications of gas chromatography can be
solved with a single-column system. However, laboratories in the petroleum in-
dustry often have to analyse samples that may contain several hundred com-
pounds.
A
complete separation of such mixtures with
a
single-column system is
impossible and even very high resolution capillary columns with efficiencies of
many thousands of theoretical plates are not sufficient to provide
full
resolution.
Using longer and longer columns will not solve the problem because it is well
known
that the separation power of a column increases only with the square root
of the column length, whereas the disadvantages of long columns (high carrier
gas pressure, long dead times and the fact that due to the compressibility of the
carrier gas only part of the column is operated at optimal flow conditions) are
directly related to the column length.
To
separate a complex mixture by chromatography, the first requirement is to
achieve a separation performance that is at least as large as the number of com-
ponents in the sample. The separation performance can be characterized by the
number of possible peaks
(NPP).
Struppe
[l]
has shown that in the range of a
single carbon number, a maximum of
200
peaks can be completely separated.
But in a real sample this number is significantly smaller because the compounds
are not uniformiy distributed. Consequently, for complex samples, the column
efficiency required to obtain a complete separation will have to exceed that of
References
pp.
266-268