Method to prepare virtual assay using time of flight mass spectroscopy
Systems and methods are disclosed for providing virtual assays of an oil sample such as crude oil based on time of flight mass spectroscopy (TOF-MS) carried out on the oil sample, and the density of the oil sample. The virtual assay provides a full range of information about fractions of the oil sample including naphtha, gas oil, vacuum gas oil, vacuum residue, and other information about the properties of the oil sample. Using the system and method herein, the virtual assay data pertaining to these several fractions of the oil sample and the oil sample itself are obtained without fractionation of the oil sample into the several components.
1. A method to evaluate an oil sample, wherein the oil sample is characterized by a density, selected from the group consisting of crude oil, bitumen and shale oil, and characterized by naphtha, gas oil, vacuum gas oil and vacuum residue fractions, the method comprising:
operating a time of flight (TOF-MS) mass spectrometer to obtain TOF-MS data over a range of mass-to-charge ratios, by analyzing the solution of the oil sample without distillation in the TOF-MS mass spectroscopy solvent, the TOF-MS data indicative of cumulative mass fraction data for a solution of the oil sample without distillation in a TOF-MS solvent;
entering into a computer the TOF-MS data;
calculating and assigning, as a function of the TOF-MS data, an analytical value (AV); and
calculating and assigning, as a function of the AV and the density of the oil sample, virtual assay data of the oil sample and the naphtha, gas oil, vacuum gas oil and vacuum residue fractions, said virtual assay data comprising a plurality of assigned data values,
evaluating the oil sample without distillation with the virtual assay data to determine an appropriate refinery or refining unit.
2. The method of claim 1 , wherein virtual assay data comprises:
a plurality of assigned assay data values pertaining to the oil sample including one or more of aromatic content, C5-asphaltenes content, elemental compositions of sulfur and nitrogen, micro-carbon residue content, total acid number and viscosity;
a plurality of assigned assay values pertaining to the vacuum residue fraction of the oil sample including one or more of elemental composition of sulfur and micro-carbon residue content;
a plurality of assigned assay values pertaining to the vacuum gas oil fraction of the oil sample including elemental compositions of one or more of sulfur and nitrogen;
a plurality of assigned assay values pertaining to the gas oil fraction of the oil sample including one or more of elemental compositions of sulfur and nitrogen, viscosity, and indicative properties including aniline point, cetane number, cloud point and pour point; and
a plurality of assigned assay values pertaining to the naphtha fraction of the oil sample including one or more of aromatic content, elemental composition of hydrogen and sulfur, paraffin content and octane number.
3. The method of claim 1 , wherein virtual assay data comprises:
a plurality of assigned assay data values pertaining to the oil sample including aromatic content, C5-asphaltenes content, elemental compositions of sulfur and nitrogen, micro-carbon residue content, total acid number and viscosity;
a plurality of assigned assay values pertaining to the vacuum residue fraction of the oil sample including elemental composition of sulfur and micro-carbon residue content;
a plurality of assigned assay values pertaining to the vacuum gas oil fraction of the oil sample including elemental compositions of sulfur and nitrogen;
a plurality of assigned assay values pertaining to the gas oil fraction of the oil sample including elemental compositions of sulfur and nitrogen, viscosity, and indicative properties including aniline point, cetane number, cloud point and pour point; and
a plurality of assigned assay values pertaining to the naphtha fraction of the oil sample including aromatic content, elemental composition of hydrogen and sulfur, paraffin content and octane number.
4. The method of claim 3 , wherein virtual assay data further comprises:
yields of fractions from the oil sample as mass fractions of boiling point ranges, including one or more of naphtha, gas oil, vacuum gas oil and vacuum residue;
composition information of hydrogen sulfide and/or mercaptans in the oil sample and/or its fractions;
elemental compositions of one or more of carbon, hydrogen, nickel, and vanadium;
physical properties of the oil sample and/or its fractions including one or more of API gravity and refractive index; or
indicative properties of the oil sample and/or its fractions including one or more of flash point, freezing point and smoke point.
5. The method of claim 1 , wherein each assay value is determined by a multi-variable polynomial equation with predetermined constant coefficients developed using linear regression techniques, wherein corresponding variables are the AV and the density of the oil sample.
6. The method of claim 5 , wherein each assay value is determined by
AD=K AD +X 1 AD *AV+X 2 AD *AV 2 +X 3 AD *AV 3 +X 4 AD *ρ*AV
where:
AD is the assigned assay value that is a value and/or property representative of an elemental composition value, a physical property or an indicative property;
AV is the analytical value of the oil sample;
ρ is the density of the oil sample; and
K AD , X1 AD , X2 AD , X3 AD , and X4 AD are constants.
7. The method of claim 5 , wherein each assay value is determined by
AD=K AD +X 1 AD *ρ+X 2 AD *ρ 2 +X 3 AD *ρ 3 +X 4 AD *AV+X 5 AD *AV 2 +X 6 AD *AV 3 +X 7 AD *ρ*AV
where:
AD is the assigned assay value that is a value and/or property representative of an elemental composition value, a physical property or an indicative property;
AV is the analytical value of the oil sample;
ρ is the density of the oil sample; and
K AD , X1 AD , X2 AD , X3 AD , X4 AD , X5 AD , X6 AD and X7 AD are constants.
8. The method of claim 7 , wherein the analytical value is an index derived from a weighted average of masses derived from the TOF-MS data.
9. The method of claim 8 , wherein the index is obtained by a function:
(
TOFMSI
)
=
[
∑
x
,
y
=
5
,
10
,
20
,
30
,
40
,
50
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60
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70
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80
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90
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95
M
x
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W
y
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[
∑
y
=
5
,
10
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20
,
30
,
40
,
50
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60
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70
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80
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90
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95
W
y
]
where:
TOFMSI is the index;
M=mass, over a range of x percentage from 0 to 100; and
W=weight fraction of the mass, that is, cumulative mass fraction over a range y.
10. A system for evaluating an oil sample, wherein the oil sample is characterized by a density, selected from the group consisting of crude oil, bitumen and shale oil, and characterized by naphtha, gas oil, vacuum gas oil and vacuum residue fractions, the system comprising:
a time of flight mass spectrometer that outputs time of flight mass spectroscopy (TOF-MS) data;
a non-volatile memory device that stores calculation modules and data, the data including the TOF-MS data, wherein the TOF-MS data is indicative of cumulative mass fraction data for a solution of the oil sample without distillation in a TOF-MS solvent;
a processor coupled to the non-volatile memory device;
a first calculation module that is stored in the non-volatile memory device and that is executed by the processor, wherein the first calculation module calculates an analytical value (AV) as a function of the TOF-MS data;
a second calculation module that is stored in the non-volatile memory device and that is executed by the processor, wherein the second calculation module calculates, as a function of the AV and the density of the oil sample, virtual assay data of the oil sample and the naphtha, gas oil, vacuum gas oil and vacuum residue fractions, said virtual assay data comprising a plurality of assigned data values; and
an output module that is stored in the non-volatile memory device and that is executed by the processor, wherein the output module prints or renders on a display said virtual assay data for evaluation of the oil sample without distillation and to determine an appropriate refinery or refining unit.
11. The system as in claim 10 , wherein virtual assay data comprises:
a plurality of assigned assay data values pertaining to the oil sample including aromatic content, C5-asphaltenes content, elemental compositions of sulfur and nitrogen, micro-carbon residue content, total acid number and viscosity;
a plurality of assigned assay values pertaining to the vacuum residue fraction of the oil sample including elemental composition of sulfur and micro-carbon residue content;
a plurality of assigned assay values pertaining to the vacuum gas oil fraction of the oil sample including elemental compositions of sulfur and nitrogen;
a plurality of assigned assay values pertaining to the gas oil fraction of the oil sample including elemental compositions of sulfur and nitrogen, viscosity, and indicative properties including aniline point, cetane number, cloud point and pour point;
a plurality of assigned assay values pertaining to the naphtha fraction of the oil sample including aromatic content, elemental composition of hydrogen and sulfur, paraffin content and octane number.
12. The system as in claim 11 , wherein virtual assay data further comprises:
yields of fractions from the oil sample as mass fractions of boiling point ranges, including one or more of naphtha, gas oil, vacuum gas oil and vacuum residue;
composition information of hydrogen sulfide and/or mercaptans in the oil sample and/or its fractions;
elemental compositions of one or more of carbon, hydrogen, nickel, and vanadium;
physical properties of the oil sample and/or its fractions including one or more of API gravity and refractive index; or
indicative properties of the oil sample and/or its fractions including one or more of flash point, freezing point and smoke point.
13. The system of claim 10 , wherein each assay value is calculated and assigned by the second calculation module with a multi-variable polynomial equation with predetermined constant coefficients developed using linear regression techniques, wherein corresponding variables are the AV and the density of the oil sample.
14. The system of claim 13 , wherein each assay value is calculated and assigned by the second calculation module with a function:
AD=KAD+X 1 AD*AV+X 2 AD*AV 2 +X 3 AD*AV 3 +X 4 AD*ρ*AV
where:
AD is the assigned assay value that is a value and/or property representative of an elemental composition value, a physical property or an indicative property;
AV is the analytical value of the oil sample;
ρ is the density of the oil sample; and
KAD, X1AD, X2AD, X3AD, and X4AD are constants.
15. The system of claim 13 , wherein each assay value is calculated and assigned by the second calculation module with a function:
AD=KAD+X 1 AD*ρ+X 2 AD*ρ 2+ X 3 AD*ρ 3+ X 4 AD*AV+X 5 AD*AV 2+ X 6 AD*AV 3+ X 7 AD*ρ*AV
where:
AD is the assigned assay value that is a value and/or property representative of an elemental composition value, a physical property or an indicative property;
AV is the analytical value of the oil sample;
ρ is the density of the oil sample; and
KAD, X1AD, X2AD, X3AD, X4AD, X5AD, X6AD and X7AD are constants.
16. The system of claim 15 , wherein the analytical value is an index derived from a weighted average of masses derived from the TOF-MS data.
17. The system of claim 16 , wherein the index is obtained by a function:
(
TOFMSI
)
=
[
∑
x
,
y
=
5
,
10
,
20
,
30
,
40
,
50
,
60
,
70
,
80
,
90
,
95
M
x
*
W
y
]
[
∑
y
=
5
,
10
,
20
,
30
,
40
,
50
,
60
,
70
,
80
,
90
,
95
W
y
]
where:
TOFMSI is the index;
M=mass, over a range of x percentage from 0 to 100; and
W=weight fraction of the mass, that is, cumulative mass fraction over a range y.