Transcript 6-a-CAPRAI_linearity.ppt

Methods and apparatus for introducing and analyse volcanic, geothermal and low
enthalpy gas samples in gas chromatographers at checked, low and variable
pressures for best quality of analyses.
Fit for any kind of gases.
Antonio Caprai
Using Giggenbach system for sampling volcanic
fumaroles and geothermal wells, usually get
samples at very low pressure, in certain cases
even less than one hundred mBar. The system
we registered (International Application
PCT/IB2005/001568 – Method and Apparatus
for Feeding Samples of Gases at Controlled
Pressure into Gas Chromatograph) fit for one
ore more gas chromatographers working at the
same or different time, and it is useful for using
only one or two points for calibration curve of a
standard of pure gases (no preparation of
particular external standard is necessary).
The problems we get in analysing this kind of
samples are various:
1.
To minimize analytical error
2.
If we need more than one run must collect several
times the gas from flask and so the internal
pressure decrease.
3.
We have to know the internal pressure of flasks.
4.
We need to have the nearest conditions between
standards and samples.
5.
We need to simplify the standardization.
6.
We need more pressure for introducing more
absolute quantity of low level amount of a certain
component.
Solve the problem with a particular apparatus fit for
working at very low and variable pressure, even
under 30 mbar.
With this introduction system we can:
1.
Minimize analytical error because of full control of
pressure.
2.
With only a single amount of sample can analyze it
several times in various Gas Chromatographers.
3.
Can read the pressure inside the flasks.
4.
Can introduce sample and standard at the same
pressure.
5.
Can have excellent standardization with one or
(maximum) two calibration points.
6.
Avoid errors in preparation of standards.
7.
Can increase pressure of low pressure samples.
Applicant:
CNR – National Research Council of Italy
D.A.S.T.-Servizio IV Rapporti con l'Industria ed i Servizi
Via dei Taurini 19 - 00185 - ROMA
Italy
HWD 325 mA
102,0
CO2 100%
100,0
98,0
96,0
94,0
92,0
90,0
0
Pressure of intr.
50
100
Area
mBar
150
200
measured
mM of gas
Conc. %
introduct
1300
5749126
84.6
0.05252
1100
4879819
84.8
0.04444
1000
4434303
84.8
0.04040
900
3997189
84.9
0.03636
700
3126073
85.4
0.02828
500
2256004
86.3
0.02020
300
1384211
88.2
0.01212
200
947450
90.6
0.00808
180
861058
91.5
0.00727
170
816863
91.9
0.00687
150
728952
92.9
0.00606
130
642530
94.5
0.00525
120
598546
95.4
0.00485
110
553941
96.3
0.00444
100
511159
97.8
0.00404
90
465899
99.0
0.00364
80
418446
100.0
0.00323
70
365933
100.0
0.00283
60
313369
99.9
0.00242
50
261446
100.0
0.00202
250