PROCESSES AND SYSTEMS FOR CHARACTERIZING AND BLENDING REFINERY FEEDSTOCKS
First Claim
1. A method for evaluating the corrosivity of a crude oil, comprising:
- withdrawing a representative sample of a crude oil feedstock to a refinery;
performing impedance measurements on the crude oil sample as a function of temperature to obtain a first electrochemical impedance spectroscopy (EIS) data, wherein the first EIS data include data for at least three frequencies;
obtaining a second EIS data on a reference crude oil sample having known corrosion properties, wherein the second EIS data include data for at least three frequencies;
analyzing the first EIS data relative to the second EIS data to evaluate the corrosivity of the crude oil feedstock, wherein the step of comparing the first EIS data with the second EIS data including comparing at least one of a resistance reading and a dielectric constant reading.
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Abstract
Refinery feedstocks can be characterized based on any of: dissociation of acids in the crude, breakup of naphthenic acid molecular associations, and/or dissociation of sulfur compounds in the feedstocks. The characterization is performed as a function of temperature via any of electrical resistivity measurement, vibrational spectroscopic analysis, voltammetry, electrochemical impedance spectroscopy (EIS) and combinations thereof The method can be practiced in any of refinery, terminal, and laboratories. It can be used in conjunction with models and hardware to optimize the usage of refinery feedstocks in the blending and valuation of the feedstocks. In one embodiment, the characterization of refinery feedstocks is via the use of EIS.
63 Citations
21 Claims
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1. A method for evaluating the corrosivity of a crude oil, comprising:
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withdrawing a representative sample of a crude oil feedstock to a refinery; performing impedance measurements on the crude oil sample as a function of temperature to obtain a first electrochemical impedance spectroscopy (EIS) data, wherein the first EIS data include data for at least three frequencies; obtaining a second EIS data on a reference crude oil sample having known corrosion properties, wherein the second EIS data include data for at least three frequencies; analyzing the first EIS data relative to the second EIS data to evaluate the corrosivity of the crude oil feedstock, wherein the step of comparing the first EIS data with the second EIS data including comparing at least one of a resistance reading and a dielectric constant reading. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for evaluating the corrosivity of a crude oil feedstock by correlating its corrosivity with dissociation of acids in the crude oil, comprising:
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withdrawing a representative sample of the crude oil feedstock, wherein the crude oil feedstock has a certain amount of acids; detecting the dissociation of the acids in the crude oil feedstock sample as a function of temperature by obtaining impedance measurements of the crude oil feedstock over a range of temperature from ambient to 700°
F.;providing impedance measurements of at least a reference oil feedstock having a known dissociation of acids; comparing the impedance measurements of the crude oil feedstock sample with the impedance measurements of the reference oil feedstock to evaluate the corrosivity of the crude oil feedstock; wherein the impedance measurements of the crude oil feedstock sample and the reference oil feedstock are carried out using a two-electrode chemical cell with an ultramicroelectrode as working electrode and a second electrode serving as both reference electrode and counter electrode. - View Dependent Claims (16, 17, 18)
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19. A method for evaluating the corrosivity of a crude oil feedstock in operations by correlating its corrosivity with molecular associations of naphthenic acid in the crude oil feedstock upon contact with at least a metal, comprising:
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withdrawing a representative sample of the crude oil feedstock, wherein the crude oil feedstock has a certain amount of naphthenic acid; exposing a metal specimen to the crude oil feedstock sample; detecting the molecular associations of naphthenic acid in the crude oil feedstock sample upon exposure to the metal specimen as a function of temperature by obtaining electrical resistivity measurements of the crude oil feedstock sample over a range of temperature from ambient to 700°
F.;providing resistivity measurements of at least a reference oil feedstock having a known corrosion rate upon exposure to the metal specimen; comparing the resistivity measurements of the crude oil feedstock sample with the resistivity measurements of the reference oil feedstock to evaluate the corrosivity of the crude oil feedstock. - View Dependent Claims (20, 21)
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Specification