U.S. patent application number 13/617276 was filed with the patent office on 2013-03-14 for site analysis system for the calculation of the isotope ratio of carbon in several gas species by means of a single analyser.
This patent application is currently assigned to Antonio Calleri. The applicant listed for this patent is Antonio CALLERI. Invention is credited to Antonio CALLERI.
Application Number | 20130064715 13/617276 |
Document ID | / |
Family ID | 44898876 |
Filed Date | 2013-03-14 |
United States Patent
Application |
20130064715 |
Kind Code |
A1 |
CALLERI; Antonio |
March 14, 2013 |
Site analysis system for the calculation of the isotope ratio of
carbon in several gas species by means of a single analyser
Abstract
The present invention relates to a system of analysis, which can
be used in a mobile laboratory in a drilling site situation or in a
similar situation, suitable for measuring (preferably in relation
to at least two partially gaseous species, which derive preferably
from a mixture extracted from a drilling mud, for example, methane,
ethane, propane and/or any other heavier hydrocarbons) the
quantities of the different isotopes of at least a same chemical
element (preferably the quantities of .sup.13C, carbon isotope with
6 protons and 7 neutrons, and of .sup.12C, carbon isotope with 6
protons and 6 neutrons, respectively) by means of a laser isotopes
analyser regulated for a single, at least partially gaseous species
which contains said chemical element.
Inventors: |
CALLERI; Antonio; (Milan,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CALLERI; Antonio |
Milan |
|
IT |
|
|
Assignee: |
Calleri; Antonio
|
Family ID: |
44898876 |
Appl. No.: |
13/617276 |
Filed: |
September 14, 2012 |
Current U.S.
Class: |
422/83 |
Current CPC
Class: |
G01N 33/2823 20130101;
G01N 30/84 20130101; G01N 2030/8868 20130101; G01N 30/88
20130101 |
Class at
Publication: |
422/83 |
International
Class: |
G01N 30/00 20060101
G01N030/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2011 |
IT |
MI2011A001647 |
Claims
1. A system of analysis, which is able to at least partially
measure the isotopic content of at least a chemical element, also
as a continuous process on site and in relation to at least two
different at least partially gaseous species containing that
element, said species being contained in at least one at least
partially gaseous mixture, which in turn was originally extracted,
preferably but not exclusively, from a drilling mud, wherein said
system comprises: at least one gas chromatograph for the mutual
separation of said gaseous species; at least one oxidation oven for
heating said gaseous species separately and consequently producing
at least one other at least partially gaseous species; and at least
one laser isotopes analyser configured to analyse said gaseous
species produced by heating.
2. The system of analysis according to claim 1, wherein the system
comprises at least one processor suitable for controlling at least
part of the components of said system.
3. The System of analysis according to claim 2, wherein the system
comprises at least the following components, which possibly are at
least partially controlled by said processor: means for
transferring each of said gaseous species to be analysed, from said
gas chromatograph to said oxidation oven; means for transferring
said gaseous species produced by heating, from said oxidation oven
to said laser isotopes analyser; and means for collecting and
concentrating said gaseous species produced by heating before
isotope analysis.
4. The system of analysis according to claim 2, wherein the system
is configured to be usable with a process which comprises a
sequence formed at least by the following steps, at least partially
controlled by said processor and whereof at least two steps can be
at least partially simultaneous: a) at least part of at least one
at least partially gaseous mixture enters said gas chromatograph;
b) said part of said mixture is at least partially separated into
at least two portions, at least one at least partially gaseous
species contained in one of these portions being different from at
least one at least partially gaseous species contained in the other
of said portions; c) at least part of at least one of said portions
enters said oxidation oven; d) said oxidation oven heats said part
of said portion, and then generates at least one at least partially
gaseous species; e) at least part of the latter generated species
enters said laser analyser, which analyses the isotope content
relative to at least one chemical element which constitutes at
least a part of the same generated species; and f) steps c) , d),
e), are repeated for at least another one of said portions.
5. The system of analysis according to claim 4, wherein: said
oxidation oven transforms said gas species to be analysed, at least
into carbon dioxide CO.sub.2; said laser isotopes analyser is
configured to analyse the isotopes of the carbon contained in the
carbon dioxide CO.sub.2; and said gas chromatograph is connected to
at least one flame ionization detector, or FID, to measure the
times of retention of the gas species and to calibrate the
system.
6. The system of analysis according to claim 3, wherein the system
is configured to be usable with a process which comprises the
sequence formed at least by the following steps, at least partially
controlled by said processor and in which at least two steps can be
at least partially simultaneous: a) at least part of at least one
at least partially gaseous mixture enters said gas chromatograph;
b) said part of said mixture is at least partially separated into
at least two portions, at least one at least partially gaseous
species contained in one of these portions being different from at
least one at least partially gaseous species contained in the other
of said portions; c) at least part of at least one of said portions
enters said oxidation oven; d) said oxidation oven heats said part
of said portion, and then generates at least one at least partially
gaseous species; e) at least part of the latter generated species
enters said laser analyser, which analyses the isotope content
relative to at least one chemical element which constitutes at
least a part of the same generated species; and f) steps c) , d),
e), are repeated for at least another one of said portions.
7. The system of analysis according to claim 6, wherein: said
oxidation oven transforms said gas species to be analysed, at least
into carbon dioxide CO.sub.2; said laser isotopes analyser is
configured to analyse the isotopes of the carbon contained in the
carbon dioxide CO.sub.2; and said gas chromatograph is connected to
at least one flame ionization detector, or FID, to measure the
times of retention of the gas species and to calibrate the
system.
8. The system of analysis according to claim 1, wherein said gas
chromatograph comprises at least: one valve, or "sample valve; one
conduit for the entry of at least a carrier gas, or "primary entry
line," and connected to at least one way of said sample valve; one
other conduit for the entry of the gaseous mixture to be analysed,
or "gas entry line," and connected to at least one way of said
sample valve; one other conduit which performs the function of
chromatographic column, or "backwashing column," and connected to
at least two ways of said sample valve; one other conduit, or
"sampling cell," and connected to at least two ways of said sample
valve; one other conduit, or "intermediate line," and connected to
at least one way of said sample valve; one other conduit for the
discharge of gas, connected to at least one way of said sample
valve; and said sample valve being able to place in contact at
least: said sampling cell at least with said gas entry line and a
discharge conduit, or said sampling cell at least with said
backwashing column and said primary entry line; said backwashing
column at least with said primary entry line and with a discharge
conduit, or said backwashing column at least with said intermediate
line and said sampling cell; and said gas entry line at least with
said sampling cell or at least with a discharge conduit.
9. The system of analysis according to claim 8, wherein the system
is configured with adequate means so as to allow said chromatograph
to operate according to a process which comprises at least the
sequence formed by the following steps, at least partially
controlled by said processor, which in turn is preferably manually
calibrated by the user, and whereof at least two steps can be at
least partially simultaneous: at least part of an at least
partially gaseous mixture, arriving from the entry line for the
gas, flows at least partially through the sampling cell and moves
towards a discharge conduit; said sample valve changes
configuration so as to place said primary entry line in contact
with said sampling cell; at least a carrier gas enters at least
partially the sampling cell, taking from the sampling cell said
part of the mixture, and draws the latter at least partially into
the backwashing column; two or more at least partially gaseous
species of said mixture are at least partially separated, or moved
away, between them and within said backwashing column; at least a
carrier gas starts to draw at least two of said gaseous species, a
"first species" and a "second species," and are preferably the
lighter components of said part of the mixture, at least partially
inside said intermediate line; and after the heaviest species to be
analysed has at least partially entered said intermediate line, the
sample valve once again changes configuration, so as to prevent at
least partially at least one heavier species from entering said
intermediate line.
10. The system of analysis according to claim 8, wherein said gas
chromatograph comprises at least: one other valve, or "storage
valve"; said intermediate line being connected to at least one way
of said storage valve; one other conduit, or "store column",
connected to at least two ways of said storage valve; said store
column performing the function of a chromatographic column; one
other conduit, or "connection line," connected to at least one way
of said storage valve; and said storage valve being able to place
in contact at least: said store column at least with said
intermediate line and said connection line, or said store column at
least with two at least partially closed sections.
11. The system of analysis according to claim 10, wherein the
system is configured with adequate means so as to allow said
chromatograph to be able to operate according to a process which
comprises at least the sequence formed by the following steps, at
least partially controlled by said processor, which in turn is
preferably manually calibrated by the user, and whereof at least
two steps can be at least partially simultaneous: at least one
carrier gas draws said first and second species to be analyzed at
least partially through said intermediate line and subsequently
inside said store column, where the latter two species preferably
at least partially move away even more between them; at least said
first species exits at least partially from said store column,
while said storage valve places in contact said store column with
said connection line, and enters at least partially said connection
line; and said storage valve changes configuration so as to place
said store column in contact with said two closed sections so that
at least said second species remains at least partially trapped
inside said store column.
12. The system of analysis, which can be used in a mobile
laboratory in a drilling site situation according to claim 10,
wherein said gas chromatograph comprises at least: one other valve,
or "final valve"; said connection line being connected to at least
one way of said final valve; one other conduit, or "holding
chamber," connected to at least two ways of said final valve; one
other conduit for the discharge of gas, connected to at least one
way of said final valve; one other conduit for the entry of the
carrier gas, or "secondary entry line," connected to at least one
way of said final valve; and one other conduit, or "exit line", for
the exit of each gas species travelling towards said oxidation
oven, said exit line being connected to at least one way of said
final valve; said final valve being able to place in contact at
least: said holding chamber at least with said connection line and
a discharge conduit, or said holding chamber at least with said
secondary entry line and said exit line; and said connection line
at least with said holding chamber, or at least with a discharge
conduit.
13. The system of analysis according to claim 12, wherein the
system is configured with adequate means so as to allow said
chromatograph to operate according to a process which comprises at
least a sequence formed by the following steps, at least partially
controlled by said processor, which in turn is preferably manually
calibrated by the user, and whereof at least two can steps be at
least partially simultaneous: at least one carrier gas draws at
least said first species at least partially through said connection
line, and subsequently at least partially inside said holding
chamber, while said final valve places said holding chamber in
contact with said connection line; said final valve changes
configuration so as to place said holding chamber in contact with
said secondary entry line; at least one carrier gas, in arrival
from said secondary entry line, flows at least partially through
said holding chamber, taking said first species and conveying said
first species at least partially into said exit line; said storage
valve changes configuration so as to place said store column in
contact with said connection line so that said second species exits
at least partially from said store column, and enters at least
partially said connection line; and at least one carrier gas draws
at least said second species at least partially through said
connection line, and subsequently at least partially inside said
holding chamber, while said final valve again places said holding
chamber in contact with said connection line; said final valve
changes configuration so as to place said holding chamber in
contact with said secondary entry line; and at least one carrier
gas, in arrival from said secondary entry line, flows at least
partially through said holding chamber, taking said second species
and conveying said second species at least partially into said exit
line.
14. The system of analysis according to claim 13, wherein the
system is synchronized so that, separately and sequentially, for
each single species of said at least two species: the single
species flows at least partially through said exit line, enters
said oxidation oven and is heated so as to produce at least carbon
dioxide; the carbon dioxide produced by the heating of said single
species is collected and concentrated by known means; and said
isotope analyzer detects the isotopic content of the carbon
contained in said carbon dioxide, which is derived from said single
species.
15. The system of analysis according claim 14, wherein said
processor controls at least said gas chromatograph, and said
changes of configuration of the valves are controlled by said
software at instants of times programmed, preferably manually, by
the user.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of the priority filing
date in Italian patent application no. MI2011A001647 filed on Sep.
14, 2011. The earliest priority date claimed is Sep. 14, 2011.
FEDERALLY SPONSORED RESEARCH
[0002] None
SEQUENCE LISTING OR PROGRAM
[0003] None
STATEMENT REGARDING COPYRIGHTED MATERIAL
[0004] Portions of the disclosure of this patent document contain
material that is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by anyone of
the patent document or the patent disclosure as it appears in the
Patent and Trademark Office file or records, but otherwise reserves
all copyright rights whatsoever.
BACKGROUND OF THE INVENTION
[0005] The present invention relates to a system of analysis, which
can be used in a mobile laboratory in a drilling site situation or
in a similar situation, suitable for measuring (preferably in
relation to at least two at least partially gaseous species, which
derive preferably from a mixture extracted from a drilling mud, for
example, methane, ethane, propane and/or any other heavier
hydrocarbons) the quantities of the different isotopes of at least
a same chemical element(preferably the quantities of .sup.13C,
carbon isotope with 6 protons and 7 neutrons, and of .sup.12C,
carbon isotope with 6 protons and 6 neutrons, respectively) by
means of a laser isotopes analyser regulated for a single, at least
partially gaseous species which contains said chemical element.
[0006] At the current state of the art, the instruments which are
commonly used for measuring the isotope ratio of carbon in
hydrocarbons, which is linked to the quantities in mass of the two
isotopes mentioned, are mass spectrometers of the IRMS (isotope
ratio mass spectrometer) type, which in fact allows for separate
investigation of the relative concentration of stable isotopes,
.sup.12C and .sup.13C, in different gaseous species. However,
instruments of this type are not suitable for site analysis because
of their dimensions and because they have to be used in particular
environmental conditions free from vibrations and with stable
temperature and pressure. These facts preclude their use in
drilling sites, both on land and at sea, where said analysis has to
take place in a continuous process.
[0007] The object of the present invention is that of producing a
system of analysis which is able to measure the isotopic content of
a chemical element, as a continuous process on site, and in
relation to at least two different, partially gaseous species
containing that element. Said species is contained in at least one
partially gaseous mixture, which in turn was originally extracted,
preferably from drilling mud. This allows accurate analyses to be
carried out in a continuous and easily manageable manner, even in
difficult environmental conditions, such as remote site locations
on land or on a sea platform.
[0008] Another type of instrumentation for analysing the isotope
ratio of carbon is known and described in patent application EP
1887342. This application is based on laser optical spectrometry,
which allows the production of an instrument of simpler application
and management and which can be used on site. However, because this
instrument is configured in such a way that the laser spectrometer
is able to quantify the relative abundance of the two stable
isotopes of the carbon only in a single hydrocarbon species, it is
not possible to analyse, the relative abundance of the two stable
isotopes of the carbon also in other hydrocarbon species in a
single analysis cycle and without modifying the configuration of
the same laser spectrometer. In fact, the operation of changing the
configuration of the analyzer leads to an unacceptable discrepancy
between the analysis and the current depth.
[0009] Another object of the present invention is that of producing
an instrument that is able to quantify the isotope ratio of a
chemical element contained in at least two partially gaseous
species in a continuous process on site. The partially gaseous
species derive from a mixture previously contained in a drilling
mud, without modifying the configuration of the isotope analyser.
Thus, there is a good correlation between the analysis and the
current depth. The latter analyser uses laser spectrometry and is
intended to measure the relative quantity of two stable isotopes of
a chemical element contained in each of said gaseous species. The
gaseous species are previously separated from the mixture by means
of a gas chromatograph controlled by software, and then transformed
one by one into a gas species, such as carbon dioxide CO.sub.2, for
which this analyser is configured. In this way, the isotope content
of several gaseous species can be analysed, continuously and at
different depths, without having to work on the analyser. Such an
operation would take too much time for numerous analyses, which
cannot be prolonged excessively because the analyses have to be
correlated to the depth in approximate real time considering that
the mixture flows continuously.
[0010] Moreover, at the state of the art, no site instrument for
the analysis of the isotope ratio of carbon in hydrocarbon gases
internally provides a system of chromatographic separation of each
gaseous species constituting the mixture sampled and comprising a
flame ionization detector or FID. This detector was introduced in
order to check the correct separation of the single gas species,
and therefore to define the correct sampling thereof before
carrying out the analysis. Without the flame ionization detector,
the instrument would be considered "blind" and therefore not able
to ensure that the same gas species is sampled in every phase in
which the analysis is to be performed.
[0011] A further object of the present invention is that of
producing an instrument which is able to quantify, also in a
continuous process on site, at least one isotope ratio of a
chemical element contained in at least two partially gaseous
species. The partially gaseous species derives from at least a
mixture previously contained in drilling mud. The instrument is
able to ensure that the gas species is exactly the same in every
phase whereof in which the analysis is performed.
[0012] To date, it has not been possible to perform isotope
analyses of continuous flows sufficiently in real time by means of
laser isotopes analysers. This is because it was not possible to
have sufficiently distanced times in sending a single gas species
to said analyser so as to allow the laser isotope analysis. In any
case, it was not possible to conclude the cycle of analysis in a
sufficiently rapid manner for all the gaseous species of geological
interest, which are usually methane, ethane and propane.
[0013] Therefore, an important object of the present invention is
that of providing an instrument with which it is possible to send
single gaseous species extracted from a mixture which flows
continuously, to a laser analyser at sufficiently large intervals
of time, and which can rapidly conclude the entire cycle of
analysis for all the gaseous species of interest in order to
perform several analyzes in real time. Thanks to the particular
configuration given here to the gas chromatograph, the gaseous
species to be analysed are sent to the isotope analyser at
sufficiently distanced intervals of time, so as to allow the same
to perform the analysis of each individual species. All the gas
species not yet analysed remain trapped in a column of the gas
chromatograph, while only one of these species is sent towards the
analyser, in such a way as to obtain a sufficient interval of time
between two successive analyses. In any case, the device takes a
sufficiently reduced time to conclude the entire cycle of analysis
of the gas species extracted at a certain depth, and in such a way
that it is possible to perform analyses at many levels of
depth.
[0014] On these bases, the present invention uses the technology
known as gas chromatography for the separation of gaseous species,
combined with a flame ionization detector (FID). The FID is
intended to correctly identify the times of gas retention under
investigation inside the various components of the gas
chromatograph. Gas chromatography, together with laser
spectrometry, is used to detect the isotopic content, and so the
isotopic ratio, of the carbon contained in each of said gaseous
species.
SUMMARY OF THE INVENTION
[0015] Firstly, it is noted that, in the present application, and
thus with reference also to the claims:
the term "valve" can denote any means for distributing at least one
fluid flow and which preferably allows, on the bases of the
configuration it takes on, the placing in contact, according to
several combinations, of at least two sections or ways or outlets
formed therein; the term "conduit" can denote any means for the
containing of at least one fluid flow; the term "chromatographic
column" can denote any means capable of separating at least
partially, preferably on the bases of different weight, at least
two gaseous species flowing in the same column; the term
"processor" can denote a software together with all the physical
devices, which constitute the hardware and which allow the software
to operate.
[0016] The present invention is, therefore, a system of analysis
that is able to:
separate at least two different partially gaseous species from a
mixture and extracted from drilling mudto be analyzed, such as
methane, ethane and/or propane, as well as other possible superior
equivalents including aromatic hydrocarbons; quantifyat least two
different isotopes and optionally at least one isotope ratio of at
least one chemical element for at least two of said gaseous
species, which is preferably carbon, and coming from the latter
species to be analyzed.
[0017] The instrument developed as part of the present invention is
therefore constituted mainly at least by the following
components:
at least one gas chromatograph for the mutual separation of said
gaseous species; at least one oxidation oven for heating separated
gaseous species and consequently producing at least one other
partially gaseous species; at least one laser isotopes analyser
configured to analyse said gaseous species produced by heating;
means for transferring each of said gaseous species to be analysed
from said gas chromatograph to said oxidation oven; means for
transferring said gaseous species produced by heating from said
oxidation oven to said laser isotopes analyser.
[0018] Moreover, the system preferably comprises at least the
following components:
means for collecting and concentrating said gaseous species
produced by heating before isotope analysis; at least one processor
suitable for controlling at least part of the components of said
system.
[0019] It is to be noted that the present device foresees the
following features:
said oxidation oven transforms said gas species to be analysed, at
least into carbon dioxide CO.sub.2; said laser isotopes analyser is
configured to analyse isotopes of carbon contained in carbon
dioxide CO.sub.2; said gas chromatograph is connected to at least
one flame ionization detector or FID, and intended to measure the
retention times of gas species and to calibrate the system.
[0020] The preferred embodiment of the device is configured, by at
least one known means, so as to be used with a process that
comprises a sequence formed by the following steps (at least
partially controlled by said processor and whereof at least two
steps can be partially simultaneous):
a) part of a partially gaseous mixture enters said gas
chromatograph; b) said part of said mixture is partially separated
into two portions, at least one partially gaseous species contained
in one of these portions being different from at least one
partially gaseous species contained in the other of said portions;
c) at least part of one of said portions enters said oxidation
oven; d) said oxidation oven heats said part of said portion, and
then generates at least one partially gaseous species; e) at least
part of the latter generated species enters said laser analyser,
which analyses the isotope content relative to a chemical element
which constitutes a part of the same generated species; f) steps c)
, d), e), are repeated for at least another of said portions.
[0021] The gas chromatograph of the preferred embodiment of the
present device is constituted at least by the following components
partially inside a heated chamber:
one valve (called "sample valve") for sampling gaseous mixture from
drilling mud, along a line where said gaseous mixture flows
continuously; one conduit for the entry of at least a carrier gas
(called "primary entry line") connected to at least one way of said
sample valve; one other conduit for the entry of the gaseous
mixture to be analysed (called "gas entry line") connected to at
least one way of said sample valve; one other conduit which
performs the function of chromatographic column (called
"backwashing column") connected to at least two ways of said sample
valve; one other conduit (hereinafter, "sampling cell") where said
gaseous mixture flows and where the same mixture is subsequently
taken over by the carrier gas, said sampling cell being connected
to at least two outlets or ways of said sample valve; one other
conduit (called "intermediate line") connected to at least one way
of said sample valve; said sample valve being able to place in
contact at least:
[0022] said sampling cell with gas entry line and a discharge
conduit, or said sampling cell at least with said backwashing
column and said primary entry line;
[0023] said backwashing column with said primary entry line and
with a discharge conduit, or said backwashing column with said
intermediate line and said sampling cell;
[0024] said gas entry line with said sampling cell or with a
discharge conduit;
one other valve (hereinafter, "storage valve") connected to the
sample valve by means of said "intermediate line"; one other
conduit for storing the gaseous species to be analyzed
(hereinafter, "store column") connected to at least two ways of
said storage valve; said store column performing the function of a
chromatographic column; one other conduit (called "connection
line") connected to at least one way of said storage valve; said
storage valve being able to place in contact at least:
[0025] said store column with said intermediate line and said
connection line, or said store column with at least two partially
closed sections;
a flame ionization analyser FID, connected to the system and in
contact with said storage valve. Said FID carries out the
synchronisation of the valves and monitors the output times of
different gaseous species under examination in order to calibrate
the device and to be sure that the same gaseous species are sent
separately to the oxidation oven; one other valve (called "final
valve") connected to said storage valve through said connection
line; one other conduit for the final sampling of the gaseous
species to be analysed, which is conveyed towards the oxidation
oven by the carrier gas. Said conduit being referred to as "holding
chamber" and connected to at least two ways of said final valve;
one other conduit for the discharge of gas, connected to at least
one way of said final valve; one other conduit for the entry of the
carrier gas (called "secondary entry line") connected to at least
one way of said final valve; one other conduit (called "exit line")
for the exit of each gas species travelling towards said oxidation
oven, said exit line being connected to at least one way of said
final valve; said final valve being able to place in contact at
least:
[0026] said holding chamber st with said connection line and a
discharge conduit, or said holding chamber with said secondary
entry line and said exit line;
[0027] said connection line with said holding chamber, or with a
discharge conduit;
said valves being able to place in contact different pairs of
outlets or ways according to the configuration which they assume,
and being controlled preferably by solenoid valves via pressurised
air; said valves preferably being pneumatic.
[0028] During the analysis cycle, these valves change configuration
automatically via the processor which controls said solenoid
valves, and at instants of time. These valves are programmed in
such a way that the gaseous species of interest arrive separated at
the oxidation oven. The initial gaseous mixture, transiting via the
backwashing and store columns (preferably filled with active
polymers able to slow down most the motion of heavier gases),
separates into the single gaseous species, which are sent singly to
the oxidation oven due to synchronisation of the same valves.
[0029] Generically, the preferred embodiment of the present system
is configured with adequate means so as to allow said chromatograph
to be able to operate according to a process which comprises at
least the sequence formed by the following steps--at least
partially controlled by said processor, which in turn is preferably
manually calibrated by the user, and whereof at least two steps can
be at least partially simultaneous:
at least part of a partially gaseous mixture (henceforth,
"mixture") arriving from the entry line for the gas, flows at least
partially through the sampling cell and moves towards a discharge
conduit; said sample valve changes configuration so as to place
said primary entry line in contact with said sampling cell; at
least a carrier gas partially enters the sampling cell, taking from
it said part of the mixture, and drawing the latter at least
partially into the backwashing column; two or more partially
gaseous species of said mixture (henceforth, "species") are at
least partially separated, or moved away, between them and within
said backwashing column; at least a carrier gas starts to draw at
least two of said species (henceforth, "first species" and "second
species") are preferably the lighter components of said part of the
mixture, inside said intermediate line; after the heaviest species
which is to be analysed has partially entered said intermediate
line, the sample valve once again changes configuration, so as to
prevent heavier species from entering said intermediate line; at
least one carrier gas draws said first and second species to be
analyzed partially through said intermediate line and subsequently
inside said store column, where the latter two species move away
even more between them; at least said first species exits from said
store column, while said storage valve is places said store column
in contact with said connection line, and enters said connection
line; said storage valve changes configuration so as to place said
store column in contact with said two closed sections so that said
second species remains trapped inside said store column; at least
one carrier gas draws said first species through said connection
line, and subsequently inside said holding chamber, while said
final valve places said holding chamber in contact with said
connection line; said final valve changes configuration so as to
place said holding chamber in contact with said secondary entry
line; at least one carrier gas, arriving from said secondary entry
line, flows through said holding chamber, taking said first species
and conveying it into said exit line; said storage valve changes
configuration so as to place said store column in contact with said
connection line so that said second species exits from said store
column, and enters said connection line; at least one carrier gas
draws said second species through said connection line, and
subsequently inside said holding chamber, while said final valve
again places said holding chamber in contact with said connection
line; said final valve changes configuration so as to place said
holding chamber in contact with said secondary entry line; at least
one carrier gas, arriving from said secondary entry line, flows
through said holding chamber, taking said second species and
conveying it into said exit line. It is to be considered that, if
said at least two gaseous species to be analyzed are more than two,
when the second species is in the holding chamber, another species
(called "third species") remains trapped in the store column as a
result of another configuration change of said storage valve.
[0030] The system is synchronized so that, separately and
sequentially, for each single species of said at least two
species:
the single species flows through said exit line, enters said
oxidation oven and is heated so as to produce carbon dioxide; the
carbon dioxide produced by the heating of said single species is
collected and concentrated by known means; said isotope analyzer
detects the isotopic content of the carbon contained in said carbon
dioxide, which is derived from said single species.
[0031] All these features will be made clearer by the following
detailed description of a possible embodiment of the present
invention, to be considered by way of a non-limiting example of the
more general concepts claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The following description refers to the accompanying
drawings, in which:
[0033] FIG. 1 is a schematic representation of the gas
chromatograph analysis circuit;
[0034] FIG. 2 is an enlargement of the zone where the sample valve
is disposed;
[0035] FIG. 3 is an enlargement of the zone where the storage valve
is disposed;
[0036] FIG. 4 is an enlargement of the zone where the final valve
is disposed;
[0037] FIG. 5 is a block diagram of the initial phase in which the
entire system undergoes washing;
[0038] FIG. 6 is a block diagram of the phase during which the
gaseous species to be analysed are taken by the carrier gas into
the sampling cell;
[0039] FIG. 7 is a block diagram of the phase during which a single
gaseous species is transported towards the oxidation oven.
DETAILED DESCRIPTION OF THE INVENTION
[0040] In FIG. 1, the lines schematically represent conduits or
columns where the gaseous species can transit and, as a general
rule, when two lines intersect completely, forming four equal
angles, two by two. The relative conduits are not in contact with
each other. The carrier gas, preferably nitrogen N.sub.2, comes in
the direction of the arrow C from the primary entry line or conduit
10, while the gas to be analysed comes in the direction of the
arrow D from the conduit or entry line for the gas 11, and can be a
continuous flow or also only a sample.
[0041] The three sample 20, storage 40 and final 50 valves can be
seen, each of which, as can be seen also in FIGS. 2, 3 and 4, is
provided with a certain number of ways or inlets, schematically
positioned at the vertices of a polygon and corresponding, only in
FIGS. 2, 3 and 4, to progressive series of numbers. Said valves can
take on at least two configurations, such that when they take on
the first configuration they place the pairs of ways in direct
contact corresponding to the pairs of vertices between which a
continuous line is placed, whereas when they take on the second
configuration they place the pairs of ways in contact corresponding
to the pairs of vertices represented by a dotted line. Henceforth
said first configuration will be referred to as configuration "A"
while said second configuration will be referred to as
configuration "B".
[0042] In FIGS. 2, 3 and 4 some conduits connected to the valves
are denoted by the corresponding number and, due to a space
requirement, interrupted partially.
[0043] As can be seen in detail in FIG. 2, configuration A, the
sample valve 20 places in contact:
the backwashing column 13 with the primary entry line 10 and a
discharge line 14, thus respectively the pairs of ways 21, 30 and
25, 24; the sampling cell 64 with the primary entry line for the
gas 11 and a discharge conduit 65, thus respectively the pairs of
ways 29, 28 and 26, 27; the compensation conduit 12 with the
intermediate line 15, thus the pairs of ways 23, 22; whereas in
configuration B, the sample valve 20 places in contact: the
backwashing column 13 with the sampling cell 64 and the
intermediate line 15, thus respectively the pairs of outlets 25, 26
and 21, 22; the entry line for the gas 11 with a discharge conduit
65, thus the pair of ways 28 and 27; the sampling cell 64 with the
primary entry line 10, thus the pair of outlets 29, 30; the
compensation conduit 12 with a discharge conduit 14, thus the pair
of outlets 23, 24.
[0044] As can be seen in FIG. 3, in configuration A, for example,
the storage valve 40 places in contact the store column 16 with the
closed ways 46 and 47, thus respectively the pairs of ways 48, 47
and 45, 46; in configuration B, instead, it places the store column
16 in contact with the intermediate line 15 and the connection line
18, thus respectively the pairs of ways 48, 41 and 45, 44.
[0045] As can be seen in FIG. 4, in configuration A, for example,
the final valve 50 places the holding chamber 19 in contact with
the secondary entry line 66 and the exit line 67, thus respectively
the pairs of ways 52, 53 and 55, 54; in configuration B, instead,
it places the holding chamber 19 in contact with the connection
line 18 and a discharge conduit 60, thus respectively the pairs of
ways 52, 51 and 55, 56.
[0046] In this example, the eventuality that the gases of interest
are methane CH.sub.4, ethane C.sub.2H.sub.6 and propane
C.sub.3H.sub.8, whereof the first is the lightest and the last one
is the heaviest, is taken into consideration. The process whereby
the instrument operates from when the gas enters the gas
chromatograph to when the heaviest gas species exits, moving
towards the oxidation oven, consists of several phases, which are
preferably controlled by specific software.
[0047] In the first phase, the sampling valve 20 is set,
automatically by the software, in configuration "A," while the
storage 40 and final valves 50 are in configuration "B". In this
way, part of the carrier gas which comes from the primary entry
line 10, as can be seen in FIGS. 1 and 2, enters the way 30, exits
from the way 21, and travels along the backwashing column 13 in the
direction of arrow E. Afterwards, it enters the way 25 and exits
from the way 24 to move towards a discharge conduit 14, thus
cleaning said backwashing column 13.
[0048] The other part of the carrier gas, which branches off from
the initial crossing, as can be seen in FIGS. 1 and 2, travels
along the compensation conduit 12, enters the way 23, exits from
the way 22 and moves, via the intermediate line 15, towards the
storage valve 40.
[0049] Subsequently, as can be seen in FIGS. 1 and 3, the carrier
gas enters the way 41 of said storage valve 40, then exits from the
way 48 and subsequently travels in the direction of arrow G and
cleans the store column 16. Subsequently, said part of carrier gas
enters the way 45, exits from the way 44, and arrives at a crossing
in which it divides into two portions.
[0050] The first of these portions is smaller, and reaches the
flame ionization analyser or FID 17, which is therefore intended to
calculate the arrival times of the various gaseous species, while
the other one travels along the connection line 18, subsequently
entering the way 51 of the final valve 50 as can be seen in FIG. 4.
The latter portion then exits the way 52, travels in the direction
of arrow H and cleans the holding chamber 19, so as to enter the
way 55 and exit from the way 56, to then reach the discharge
60.
[0051] FIG. 1 also shows the supply lines to the FID of air 61 and
hydrogen 62, as well as the discharge line for condensation 63.
[0052] As shown in FIGS. 1 and 2, the gas mixture to be analysed,
comes from the entry line for the gas 11, enters the way 28, exits
from the way 29, travels in the direction of arrow L along the
sampling cell 64, enters the way 26 and exits, moving towards the
discharge conduit 65, from the way 27.
[0053] The second phase starts up when the initial valve 20 changes
configuration at the command of the synchronised processor, so that
the portion of carrier gas which arrives at the way 30 is forced to
travel along the sampling cell 64, passing from the way 29 and in
the direction of arrow L, taking the gas content thereof.
Subsequently this flow of carrier gas, together with the mixture
collected, traverses the way 26, exits from the way 25 and travels
along the backwashing column 13 in the direction of arrow F, to
then pass through the ways 21 and 22 and flow into the intermediate
line 15.
[0054] When the gases exit from the way 22, the gases are already
at least partially separated because they have travelled along the
backwashing column 13, which is a separation chromatographic
column, i.e., it has the capacity to slow down most of the heavier
gases. During this phase, the gaseous mixture, coming from the
entry line for the gas 11, flows continuously in the case of
continuous analysis. The gaseous mixture flows through the ways 28
and 27, directly towards the discharge conduit 65, in such a way
that successive analyses are fairly faithful to the current
depth.
[0055] The system is synchronised, preferably by means of the
processor. This is done in such a way that the sample valve 20
returns to configuration A, triggering the third phase, when the
gas species of interest (in this case methane, ethane and propane)
are drawn into the intermediate line 15, so that they alone are
transported towards the storage valve 40. Since propane is the
heaviest gas, the sample valve 20 returns to configuration A when
the entire propane portion has exited from the way 22. Methane and
ethane are lighter, and are in a more advanced position, along said
intermediate line 15, towards the storage valve 40.
[0056] During said third phase, the carrier gas returns to wash in
the countercurrent from the backwashing column 13, cleaning the
gaseous species from the backwashing column 13 that are not of
interest, while the in-coming gaseous mixture continues to travel
continuously along the sampling cell 64. The gaseous mixture then
moves towards the discharge 65 to ensure that the analyses are
correlated to depth at a reduced time lag. The compensation conduit
12 is so called because it serves to ensure that, in this phase,
the carrier gas (which arrives from said compensation conduit 12
and flows into the intermediate line 15) arrives with the same load
losses whereto the flow of carrier gas was subject. In the previous
phase, the carrier gas flowed into said intermediate line 15 after
having travelled along the backwashing column 13.
[0057] Methane, which is the lightest of the three gases, arrives
first at the storage valve 40 and traverses (as seen in FIGS. 1 and
3) the ways 41 and 48 sequentially--said storage valve 40 being in
configuration B--to then enter the store column 16. Subsequently,
Methane enters the way 45 and exits definitively from said storage
valve 40 through the way 44, to then move towards the FID in part
and the final valve 50 in part.
[0058] The first of said parts, which is usually smaller, only
serves to calculate the arrival times of the various gases during
calibration and synchronise the valves, preferably by means of the
processor and preferably manually by the user. On the other hand,
the second of said parts travels along the connection line 18 and
arrives at the final valve 50. Said part of methane (as shown in
FIGS. 1 and 4) enters the way 51 and exits from the way 52--said
final valve 50 being in configuration B--to then travel along the
holding chamber 19.
[0059] When all the methane is inside the holding chamber 19, the
storage valve 40 passes automatically into configuration A, as a
result of the synchronised processor, so as to trap ethane and
propane in the store column 16. The store column 16 is in direct
contact with the closed ways 47 and 46 in this case, as can be seen
in FIG. 2. This condition is known as "store column" and
corresponds with the fourth phase, during which the carrier gas
that arrives from the intermediate line 15 traverses the valve 68
(referred to as "tap valve") connected to the ways 42 and 43 of the
storage valve 40. After the carrier gas flows into the connection
line 18, the carrier gas enters the discharge line 60, and passes
through the final valve 50 (as seen in FIG. 1).
[0060] During the successive fifth phase, the final valve 50 also
takes on configuration A, so that the carrier gas that arrives from
the secondary entry line 66 (as seen in FIGS. 1 and 4) travels
along said holding chamber 19 after having traversed the ways 53
and 52. The carrier gas can then take on the methane located in
said holding chamber 19. Subsequently, the methane is transported
into the exit line 67, passing through the ways 55 and 54, and
heads for the oxidation oven.
[0061] In the sixth phase, the storage 40 and final 50 valves are
once again in configuration B, so that the carrier gas coming from
the holding chamber 19 travels to the discharge 60, passing
sequentially through the ways 55 and 56 of said final valve 50. On
the other hand, ethane, which is trapped in the storage column 16,
can travel towards the final valve 50 and the FID 17. The system is
preferably synchronised so that until all the ethane reaches the
holding chamber 19, the propane, which is heavier, does not yet
travel along the entire store column 16. In this way, the previous
trapping effect acts effectively only on the portion of ethane.
[0062] The seventh phase starts when, the storage valve 40 moves
into configuration A at the moment at which all the ethane is in
the holding chamber 19. This traps the propane in the store column
16, restoring the condition of "store column". Subsequently, the
final valve 50 also moves into configuration A, triggering the
eighth phase.
[0063] In the eighth phase, the carrier gas coming from the
secondary line 66 conveys the ethane towards the oxidation oven
through the exit line 67.
[0064] In phase nine phase, both the storage 40 and final 50 valves
are again in configuration B. Thanks to the flow of carrier gas
arriving from the intermediate line 15, a portion of propane flows
towards the final valve 50 through the connection line 18, while
the other portion of this gas moves towards the FID, which
calibrates the retention times.
[0065] Phase ten starts when the final valve 50 takes on
configuration A (i.e., after the entire portion of propane heading
for the final valve 50 has entered the holding chamber 19). Said
portion is conveyed by the carrier gas coming from the secondary
entry line 66 (as seen in FIG. 4) into the exit line 67, and then
drawn towards the oxidation oven.
[0066] In phase eleven, the final valve 50 is once again in
configuration B. The system therefore returns to the initial
conditions and the analysis sampling cycle begins again.
[0067] All valve configuration changes are managed by the
processor, so that the user only has to start the instrument, which
is controlled by software. The phase of preliminary calibration,
and therefore of software programming, is preferably performed
manually by the user.
[0068] In FIG. 5, the second phase is schematised. It shows the
carrier gas, N.sub.2, entering the sampling cell, taking the gas
species indicated as C.sub.1, C.sub.2, and C.sub.3, and
transporting them to the store column. The other portion of carrier
gas travels along the compensation conduit to the discharge.
[0069] In FIG. 6, the third phase is schematised, during which
C.sub.1, the lightest of the gases to be analysed (i.e., methane)
is transported into the holding chamber, while C.sub.2 and C.sub.3
remain trapped in the store column. The path of the incoming
carrier gas can be seen, part of which washes in against the
backwashing column to then go to the discharge. Another part of the
carrier gas travels along the compensation conduit, entering the
store column and drawing the lightest of the gases towards the
holding chamber and the FID.
[0070] FIG. 7 schematises the fifth phase, during which the carrier
gas coming from the secondary entry line enters the holding
chamber, takes the content of C.sub.1, and transports the gas to
the oxidation oven.
[0071] Said gas is transformed preferably into carbon dioxide
which, after having passed through a sampler that collects the gas
and concentrates it, goes to an isotopes analyser (preferably
laser) that is configured appropriately and whose functions are
known in the art. Said analyser is mainly based on detecting light
absorption by atoms .sup.12C and .sup.12C at two different
wavelengths. The configuration has to be regulated especially on
the basis of the gas to be analysed, in our case CO.sub.2.
[0072] Variations in the constitution of the system described and
of the process whereby it operates are possible, in any case coming
within the scope of protection of the present patent according to
what is expressed in the claims.
* * * * *