JP3090930B2 - Method and apparatus for chromatographic analysis of hydrocarbons, and hydrocarbon purification operations using the same - Google Patents

Description

Description: FIELD OF THE DISCLOSURE The present invention relates to a method for purifying or upgrading hydrocarbon feeds using chromatographic analysis of hydrocarbon oils. The present specification also discloses a method for chromatographic analysis of a hydrocarbon oil and an apparatus therefor. The invention relates in particular to a method for determining the levels of components present in hydrocarbon oils, especially aromatic hydrocarbons.

Chromatography is a well-informed and widely used laboratory technique for the separation and confirmation of components of liquid mixtures such as solutions, relying on different relative affinities between the stationary phase and the mobile phase in contact with the stationary phase .

In a typical example of chromatography, the stationary phase is a suitable particulate solid material that is substantially uniformly packed into tubes to form a column of stationary phase material. The mobile phase can be the fluid under study, or more usually the solution under study. The solvent used in the solution is usually first passed through a column of solid stationary phase, followed by a small sample containing the solution of the liquid under study, and then the solvent alone. The components of the fluid have different affinities for the stationary phase and therefore
It is held for different times in different areas along the length of the column. It is clear that the affinity for some components is low and practically unretained, but for the other components it is high and the component is introduced into the column and exposed to the potential elution characteristics of the solvent. Would not be recovered from the column after a considerable amount of time.

BACKGROUND OF THE INVENTION Chromatography has been used as a means to analyze mixtures of hydrocarbons and other compounds found in petroleum.

In Petroanalysis 81, Chapter 9, a hydrocarbon mixture mixed with a solvent produces an eluate that is recovered from the outlet end of a chromatographic column, which converts the next type of molecular species into a saturated hydrocarbon ( (For example, parasines and naphthenes), olefins and aromatic hydrocarbons. Residual molecular species that are (in general) polar compounds have a relatively high affinity for solid chromatographic materials, interrupt the flow of solvent, and instead have a relatively high affinity for, for example, heteroaromatics Replacing with a different solvent only allows a fairly complete recovery in a reasonable time. The different solvents are passed in the opposite direction to the first solvent, and after a reasonable time interval of this so-called backflush, the polar compound (resin) is present in the backflush eluate. Changing the solvent from a first solvent, pentane, to a second solvent, methyl t-butyl ether, uses two different eluent detectors, one using refractive index and another using ultraviolet absorbance at 300 nm. Need.

Backflushing is inconvenient because of the mechanical complications involved in the automation of chromatography equipment that uses it, and because it does not inherently guarantee complete recovery of species that are strongly adsorbed by the column stationary phase. .

Journal of Liquid Chromatography, 3 (2), 22
In 9-242 (1980), hydrocarbon mixtures containing asphaltenes are only subjected to chromatographic analysis after mixing the mixture with hexane, separating out by filtration and precipitating asphaltene as determined gravimetrically. The hexane solution of residual hydrocarbons is then passed through a column of particles of μ-Bondapak-N 粒子₂ where it is first saturated hydrocarbons and then directional groups, as determined by the refractive index of the eluent. It is separated into eluents containing hydrocarbons. The resin retained on the column is backflushed from the column and is determined by the difference. The separation properties of the column are maintained for a repetitive retention time after every 20 samples by flushing it with a solution of 1/1 methylene chloride / acetone and subsequent regeneration with methylene chloride and hexane. Changes in the refractive index of the eluent, indicative of the presence of each species, are determined by a Hewlett-Packard 33 using a so-called "zero" type method.
Monitored by the 54B computer and correlated with the absolute amount of the species. Disadvantages of this method are: (1) the technique is not readily available for automatic operation because asphaltenes are measured gravimetrically rather than chromatographically;
(2) Backflushing is used and not all material in the sample supplied to the column is recovered in the eluent as evidenced by the need for stated periodic column washing (further mention of this significant problem is given later). Done);
(3) the refractive index detector used has a varying response with each type of molecule group, such as paraffins, naphthenes, aromatics and resins, and thus has a given mass for a given mass independent of the nature of the feedstock sample being analyzed. The inability to give a universal response.

Journal of chromatography
Chromatography, 206 (1981) 289-300, Bollet et al. Describe a rapid high-performance liquid chromatography technique for separating heavy petroleum products into saturated, aromatic and polar compounds. Silica bound the Enuita ₂ column containing stationary phase [ "LiChrosolv® (Lichrosorb) NΗ _2"] is used. Two chromatographic analyzes are required for determining the composition of the sample. In the first analysis, saturated compounds are separated from aromatic and polar compounds using hexane or cyclohexane as mobile phase.
In the second analysis, saturated and aromatic compounds are separated from polar compounds using 85% by volume cyclohexane, 15% by volume chloroform as mobile phase. The eluent is monitored for saturated, aromatic and polar compounds by differential refractometry and for polar compounds by UV photometry. The proportion of saturated and polar compounds can be determined by these monitoring techniques, and the phase splitting of the aromatic compound is said to be found by the difference. However, the method, like all other reports of high performance liquid chromatography (HPLC) for the analysis of samples of heavy hydrocarbon mixtures, provides a means and method for quantitative and feed independent detection and monitoring. Limited by lack. Therefore,
"Response factors" for both refractive index (RI) and ultraviolet (UV) detectors, "semi-preparative liquid chromatography"
Separate a large sample of feed material, known as
The recovered analytes must then be derived gravimetrically (after removal of the solvent (s) added to the sample for chromatographic separation). The response factor depends on the nature of the feedstock and its boiling range, thus
It is essential to perform relatively large-scale separations to obtain accurate results in HPLC analysis. Thus, the potential benefits of speed and high resolution possible with HPLC have heretofore not been fully realized. The method of Bollett et al. Is compared with the method of the present invention in comparative examples given below.

Klevens and Platt, Journal of Chemical Physics (J. Chem. Phys.), 1
7 : 470 (1949). Similarities have been reported in the total oscillator strength for the electron transfer of cata-condensed aromatic hydrocarbons. However, the paper is not relevant to HPLC analysis, which uses a UV detector operated in a specific wavelength range for HPLC to derive an integrated oscillator strength output to quantify aromatic carbon in petroleum and shale oil feedstocks. I do not recognize or suggest what I can do. In addition, the cata-condensed aromatic hydrocarbons only make up a small fraction of various aromatic hydrocarbons in hydrocarbon feedstocks, such as petroleum. Cata
Other aromatic compounds are also generally present in the hydrocarbon feed, including para-condensed aromatics, alkylaromatics and thiophene aromatics, which behave spectroscopically differently from condensed aromatic hydrocarbons.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for purifying and / or improving hydrocarbons using chromatographic methods. Also disclosed herein is an apparatus for controlling and / or optimizing the method.

Another object of the present invention is to solve the problem of quantifying aromatic hydrocarbons in a hydrocarbon oil.

Another object of the present invention is to determine not only aromatic hydrocarbons but also saturated hydrocarbons and polar compounds in hydrocarbon oils, and furthermore, using this information and the qualitative levels of aromatic hydrocarbons, Is to determine the degree of saturation substitution of the aromatic and polar components.

Herein, a simpler, broader and more accurate method of analyzing a mixture of compounds (especially, but not exclusively, a mixture of hydrocarbons) by liquid chromatography,
And a device.

The method for chromatographic analysis of a hydrocarbon oil used in the method of the present invention comprises the steps of: (a) passing a mixture of a hydrocarbon oil and a carrier phase into contact with a chromatographic stationary phase for a first time interval; Retaining the components of the hydrogen oil on the stationary phase; (b) after step (a), displacing the mobile phase with a second phase to elute the various retained components of the oil from the stationary phase at different time intervals. Contacting and passing the stationary phase over a time interval to recover the mobile phase in contact with the stationary phase together with the components eluted from the stationary phase; (c) recovering at least a portion of the recovered mobile phase from about 200 to about 4
Irradiating with a UV light having a wavelength range in the range of 00 nm for a sufficient time period that the recovered components in the recovered mobile phase are exposed to said irradiation, said mobile phase being a UV light in said wavelength range. (D) monitoring the absorbance of the UV light by the illuminated component over the wavelength range and obtaining an integral of the absorbance over the wavelength range as a function of photon energy; and e) measuring the magnitude of the resulting integral for at least one selected time period corresponding to the elution of one or more components.

The mobile and carrier phases can be liquids or gases or critical fluids. Usually they are liquids.

In a preferred method of practicing the invention, the mobile phase recovered from the stationary phase is irradiated with UV light having a wavelength range in the range from 230 to 400 nm. By multiplying the scale factor 2 by the derivation of the absorbance integral, the magnitude of the derived absorbance integral is doubled, and the magnitude of the integral of the mobile phase recovered from the stationary phase in step (e) is doubled. It is measured for a time corresponding to the polar component.

In a preferred method of practicing the invention, the absorbance of said UV light by said irradiated components is monitored using a diode array detector.

Also disclosed herein is a calibration for measuring aromatic hydrocarbons of various ring numbers present in hydrocarbon oils. Calibration is tested by the disclosed method with samples of hydrocarbon oils with known aromatic rings present to associate different times at which different aromatic hydrocarbons elute from the stationary phase with the ring numbers of these different aromatic hydrocarbons Is substantially achieved by doing so. This method is described in detail below.

According to another aspect of the present invention, there is provided a method for refining or upgrading a petroleum hydrocarbon feed, the method comprising the steps of: A method is provided for determining the presence level of a component and controlling the operation of the process based on the presence level determined for the at least one component.

Usually, but not necessarily, the control of the operation of the process is such that the value of the presence level of said at least one component does not exceed a predetermined value.

One preferred method that can be used in the present invention is a method for the chromatographic analysis of hydrocarbon oils that may or may not contain asphaltenes, comprising: (a) a sample of the oil and 7.6-8.8 cal ^0.5 forming a mixture with a weak solvent having a solubility parameter in the range of cm- ^1.5 ; (b) combining said mixture with: (i) substantially all of at least the following functionalizing groups;
Η ₂ , —CN, —NO ₂ , charge transfer adsorbent, charge transfer adsorbent functionalized with trinitroanilinopropane or tetranitrofluorene, any of the foregoing homologs, and two or more of the foregoing A solid chromatographic stationary phase having surface hydroxy groups substantially completely functionalized with functionalizing groups selected from the group consisting of: (ii) no more than 5.0 in a mobile phase containing 0.03% by volume of cyclohexane and isopropanol (preferably Is 2.5 or less) Coronene capacity factor
(Iii) contacting and passing through a solid chromatographic stationary phase selected from: (iii) a solid chromatographic phase comprising a combination of the features of (i) and (ii); Contact the chromatographic stationary phase and 7.
Passing a weak solvent (preferably cyclohexane) having a solubility parameter in the range of 6-8.8 cal ^0.5 cm- ^1.5 at least during and after step (b) to recover the weak solvent in contact with the solid stationary phase; d) monitoring the weak solvent recovered in step (c) for a second time period including at least a time interval after the first time period to detect an eluent containing aromatic hydrocarbons; ) Monitoring the weak solvent recovered in step (c) and detecting an eluent containing saturated hydrocarbons simultaneously with and after step (d); (f) contacting said solid chromatographic stationary phase Let 8.
Passing a strong solvent having a solubility parameter in the range of 9 to 10.0 for at least a third time period after the second time period to recover the strong solvent in contact with the stationary phase; (g) step ( f) monitoring the strong solvent recovered in step f) to detect an eluent containing heteroaromatics, polar compounds and asphaltenes; and (h) contacting said solid chromatographic stationary phase for at least a third time period. Recovering the strongly denatured solvent in contact with said stationary phase through a strong solvent denatured with a hydrogen bonding solvent (eg, an alcohol) that is miscible with the strong solvent for a subsequent fourth time period; and (i) Monitoring the recovered strongly denatured solvent recovered in step (h) to detect an eluent containing a moiety selected from at least one of the group consisting of polar compounds and asphaltenes. There is a method.

Preferably, the change from a weak solvent to a strong solvent takes place over a period of time, ie there is a gradual change of the solvent rather than a step change. It is observed that good separation is achieved in this way.

For step (h), the strongly polar and / or hydrogen bonding solvent preferably has the following properties: (i) dissolves polar compounds and asphaltenes of the type in which they are found or expected in the sample; Must be able to do it. As a rule of thumb, polar solvents or solvent combinations between toluene and carbon disulfide meet this requirement, and dichloromethane is a convenient and preferred solvent that meets this criteria.

(Ii) it must be able to displace the most polar heavy oil molecules from the solid sorbent material. The addition of one or more alcohols miscible with it to the solvent gives this property, and when the solvent is based on dichloromethane, convenient and preferred alcohols have a volume concentration in the range of 1 to 50%, for example 10% by volume. Or in the vicinity thereof. (Iii) When ultraviolet spectroscopy is used for mass detection, as described herein, the solvent (or combination solvent)
Must be transparent to UV light within the wavelength range used. (Iv) If a mass detection step is used that requires removal of the solvent (eg, gravimetric analysis, flame ionization, among others), the solvent is relatively volatile to facilitate separation of the solvent-free eluent. The solvent must not associate very strongly with the polar molecules in the eluent.

Preferably, step (j) is performed by contacting the weak phase with the stationary phase in one direction after step (i) and passing it through at least a fifth time period after the fourth time period. The weak solvent is preferably the same as or is completely miscible with the weak solvent of step (c). Preferably, after step (j), steps (a) to (j) comprise step (a)
Repeat as described above with other oil samples.

Monitoring for the eluent during steps (e), (g) and (1) is performed by UV absorption using UV of the selected wavelength;
The solvents used during steps (a), (c), (f) and (h) are preferably transparent to UV of the selected wavelength.
A very significant advantage of using UV absorption to monitor the eluent is that it can be used for accurate measurement of aromatic carbon mass, as described below.

Aromatic compounds with different ring numbers and substitutions show different UV absorption photometric spectra. Thus, a single wavelength cannot be carried for all of those measurements. Each aromatic form has a different intrinsic absorbance per mole unit (extinction coefficient) at a given wavelength and cannot be assigned to a constant response factor related to absorbance to mass eluted from the column in a complex mixture. A preferred method of practicing the present invention has been devised to overcome this limitation. New method is area 200-400
Use the total UV absorbance spectrum in nm. Spectra can be quickly taken with oil components eluted from the chromatography column with a diode array detector. Examples of these detectors in oil analysis have been published [e.g. Erdol und Kohle-Erdga by KWJost et al.
s-Petrochemie) 37 (4): 178 (1984)], but UV
There is no report on the quantitative measurement of aromatic carbon from the spectrum. According to the present invention, it has been found that the mathematical derivation, referred to as the integrated oscillator strength (Q), calculated from the total absorbance spectrum, is directly proportional to the level of aromatic carbon. The quantity Q is defined as follows: Q = ∫A (ε) dε (1) where A = absorbance, ε = photon energy, and the integration is taken over the range 200-400 nm.

The quantity Q is simply integrated over that time period to derive the mass of aromatic carbon eluted from the column during any time period defining the oil component, then multiplied by an appropriate constant reflecting the optical path, integration time, etc. Can be

Next, one way in which Q can be determined in the case of a diode array detector is described. Each detector produces an output signal proportional to the light intensity 1 it detects. The computer converts each detector output to an amount A (λ) —that is, absorbance, where λ represents wavelength— And I ₀ is the intensity of the UV source. The bandwidth Δλ received by each individual detector in the detector array is the same (eg, 2 nm), but the wavelength changes from each detector to the next (by an increment or decrement equal to the bandwidth). Therefore, the computer adds the weighting factor to the quantity A (λ) , And sum over the entire UV spectrum to derive the integrated oscillator strength Q.

The validity and accuracy of this method was confirmed by comparison with model components of known weight injected into the chromatography system. Some examples are given in Table 1.

The measured integrated oscillator strength (Q) for polar compounds is multiplied by a factor of about 2.0 (or about 2.0% before measuring the integrated oscillator strength), since some of the spectral region cannot be measured due to solvent (eg, dichloromethane) absorbance. Detect aromatic carbon (multiplied by a factor of 2.0). As shown in FIG.
Comparison with the results of aromatic carbon identification by nuclear magnetic resonance (NMR) for various oil samples confirmed that this integrated oscillator strength method or technique was accurate for all oils. Here, the horizontal axis of FIG. 1 represents the result (unit:% by weight) of ¹³ C-NMR for aromatic carbon, and the vertical axis represents the predicted value (unit: weight) obtained by integrating A (ε) dε.
% By weight). The linear graph showing the primary correlation between the NMR value and the integrated oscillator strength value indicates the parity. The data also fit the parity line for oils with very different degrees of saturation, such as vacuum gas oil and coker gas oil, and oils with very different polar content, such as hydrotreated gas oil and vacuum resid.
The theoretical basis for the independence of this quantity for aromatic types is not completely understood.

The total mass of the components eluted from the column can be determined, for example, by differential refractometry, solvent evaporation followed by flame ionization of the oil, or solvent evaporation followed by light scattering of residual oil droplets. There are commercially available detectors for each of these operations. Differential refractive index measurement has the disadvantage that the refractive index of the component varies depending on the aromaticity of the component and on the degree to which the saturated carbon is paraffinic or naphthenic. Because of these drawbacks, using response factors that depend on the type of feedstock,
It is necessary to relate the measured refractive index to the mass of the eluted component. Therefore, it is preferred that the preferred method of practicing the present invention use flame ionization or light scattering followed by solvent evaporation to determine the total mass of the oil component independent of the feedstock composition or feedstock type. In the case of flame ionization, the particular instrument used [Pittsburgh Conference on Analytical Chemis 1983;
The flame ionizer described by JBDixon of Tracoa Instruments in Trial Article No. 43) was found to produce some volatilization of low boiling range oils as well as solvent evaporation, thus reducing the vacuum distillation residue. Most useful with oil. In the case of light scattering, it has been found that the light scattering response is a complex function of the mass of the eluted material, and an appropriate calibration function must be derived. Recent announcements [THMourey and LEOppenheimr], Analytical Chemistry,
56 ; 2427-2434 (1984)] addressed the use of a light scattering detector for HPLC of polymers. It has been shown by the inventors of the present invention that this detector can be used for oil systems to measure the mass of all components regardless of feedstock type. The calibration function is as follows: mass = K ₁ ^* (response) ^X (2) where x ≦ 1 at low response intensity; mass = K ₂ ^* (response) ^y (3) high Y ≧ 1 in response strength.

K ₁ and K ₂ are constants.

Combinations using one detector to measure aromatic carbon mass and the other to measure total mass differ (or ratio) the saturated carbon substitution
To make decisions. This seems to be a whole new concept in HPLC. Its relevance was confirmed by comparison between HPLC and mass spectrometry and by showing that the aromaticity of the individual aromatic and polar components increased as expected during heat treatment.

According to a preferred application, at least one sample of the hydrocarbon mixture is analyzed by the method described herein, whereby: saturated, aromatic, polynuclear aromatic, polar compounds, asphaltenes and at least A method for assessing the quality of a hydrocarbon mixture comprising determining a proportion of a species selected from at least one of the mixture comprising at least two. The hydrocarbon mixture can be a feedstock for the refining process or an intermediate processing oil between two refining stages.
The evaluations made by this preferred method of the present invention adjust the purification steps or steps as needed (within their acceptable operating limits) to meet the optimal specifications for the product and / or intermediate products. Alternatively, it allows the production of products and / or intermediate products having closely similar compositions.

The present invention also provides, in one aspect, a method for refining or upgrading a petroleum hydrocarbon feed containing asphaltenic material, the method comprising the steps of:
Passing the feed through a fractionator having a temperature and pressure gradient, the components being recovered from respective areas of the fractionator;
In addition, discontinuous samples of the gas oil fraction containing gas oil components boiling in the gas oil boiling range recovered from the gas oil recovery area of the device are taken from the recovered gas oil fraction at intervals and analyzed by the method described in this section. A method for generating a signal indicative of the amount of asphaltene material present in each sample and for use in adjusting the operation of the fractionator so that the amount of polar components in the gas oil component is maintained below a predetermined amount.

In yet another aspect, the present invention is a method of refining or upgrading a petroleum hydrocarbon feed, the feed being passed through a catalytic cracking unit to convert the feed to a cracked product comprising the upgraded hydrocarbon material. , A discontinuous sample of the feed going to the catalytic cracking unit is taken at intervals and analyzed by the method described herein, and the polar component and the aromatic component having at least three rings (hereinafter referred to as “3+ ring aromatic (E.g., "hydrocarbons") when said signal corresponds to an amount of said at least three ring aromatic and polar components exceeding a predetermined amount; and / or
At the corresponding time, the feed is mixed with a high quality feed, or subjected to catalytic hydrogenation, or both mixing and hydrotreating, and the amount of mixing is increased and decreased according to the magnitude of the signal. And / or a method for increasing and decreasing the strength of the catalytic hydrotreating, respectively.

In another aspect, the present invention relates to an asphaltenic substance, an aromatic component containing at least three conjugated aromatic rings (hereinafter, “3+
A process for refining and upgrading a petroleum hydrocarbon feed comprising undesirable contaminants selected from a mixture comprising at least two of said contaminants and a polar component. Mixing the refining agent stream with the hydrocarbon feed stream under selective refining conditions;
And separately recovering from the resulting mixture: (i) a stream of a hydrocarbon raffinate having a low content of polar and aromatic components; and (ii) a stream of a mixture comprising a solvent and at least one of said contaminant components. At discrete intervals in the raffinate stream, each of which is analyzed by the methods described herein to generate a signal indicative of the amount of the contaminant component, which may be used, directly or indirectly, to determine the amount of raffinate in the raffinate stream. A method is provided for varying the purification conditions such that the amount of the contaminant is maintained at or below the selected amount.

DETAILED DESCRIPTION OF THE INVENTION In each description, only those features directly related to the disclosed embodiments of the present invention are described, not features well known to those skilled in the art.

Fig. 1 shows six new light oils (VGO) and one heavy coker light oil (HKG).
O), 3 de-historized oil (DAO), 5 heavy Arabian vacuum resid (HAV)
R) Obtained from NMR measurements and integrated oscillator strength I on samples of fractions and 4 vacuum resids, and expected aromaticity was obtained from integrated oscillator strength. The measured polar aromatic nuclei were multiplied by a factor of 2.0. It is clear that this method for UV detection gives a quantitative measurement of aromatic hydrocarbons that is independent of feedstock type. Thus, the requirement for a response factor is eliminated.

Referring now to FIG. 2, apparatus 10 includes a chromatographic column 11 having an inner diameter of 4.6 mm and a total length of 25 cm. Column 11 is a commercially available, substantially pure N 実 質₂ functionalized silica in finely divided form having an average particle size in the range suitable for high performance liquid chromatography (HPLC), eg, 5-10 μm, by well known slurry methods. Filled with stationary phase.

A conduit 12 extends from the upstream end of the column to a sample injection valve 13, and the sample is injected into the valve 13 and the conduit 12 from a sample injection line 14.

The solvent pipe 15 extends from the upstream end of the valve 13 to the downstream end of the solvent mixing chamber 16 which is connected to the two solvent pipes 17, 18 and receives different solvents from appropriate pumps 19, 20, respectively. The operation of the pumps 19, 20 is regulated by a microprocessor (not shown). Each pump 19, 20 is coupled to receive a respective solvent from its source (not shown). A third pump can optionally be added, or a single pump with proportioning inlet valves for different solvent vessels can be used.

At the downstream end of the column 11, a conduit 21 transfers solvent (s) and eluent from the column to a variable wavelength ultraviolet detector 22, then to a mass sensitive or mass responsive detector 23, and then to a sample disposal point and / or collection and ( Or) leading to a separation device (not shown). Mass sensitive or mass responsive detector 23 can be a detector that monitors refractive index, flame ionization or light scatter (after evaporation of solvent from the sample) or produces a signal in response thereto.

During analysis, the microprocessor controller has two pumps 19,
The 20 runs are adjusted to maintain a substantially constant flow rate through the column 11 of 0.5-2.9 ml per minute. Initially, a weak solvent is used, which is substantially transparent to UV light and has sufficient solubility parameters to dissolve all components of the sample introduced into the column, but the solubility parameters are determined by HPLC in the sample. Not so high that it is not possible to distinguish relatively sharply between the different chemical types. Solubility parameter, delta,
Is the square root of the quotient of the energy of evaporation divided by the molecular volume [Encyclopedia of Chemical Technology by CA Hansen et al. And Kirk and Othmer.
emical Technology), 2nd edition, supplement, pages 889-910], that is, Delta (Ev / Vm) ^0.5 . The solubility parameter of the weak solvent should be in the range of 7.6 to 8.8 cal ^0.5 cm- ^1.5 , and the preferred weak solvent is cyclohexane, which dissolves all hydrocarbon components of the hydrocarbon oil sample without asphaltene precipitation. Other weak solvents that can be used in place of cyclohexane are nonane, decane, dodecane, hexadecane, eicosane and methylcyclohexane, and combinations of at least two of the foregoing. Preferably, the solvent used is cyclohexane containing a minor proportion of a polar solvent to maintain the adsorptivity of the stationary phase at a constant value due to the deactivation of residual silanol groups on the stationary phase. Preferred polar solvents for this purpose are alcohols, especially 2-propanol, preferably a mixture of 99.99 volumes of cyclohexane and 0.01 volumes of 2-propanol is pump 19
To the column 11 for the first time period of the operation.

During the first time period of operation, a sample of the hydrocarbon to be analyzed is sent via line 14 at a reference time into the injection valve 13 where it mixes with the weak solvent from the pump 19 and precipitates, e.g. Form a substantially homogeneous solution that is free of asphaltenes. The sample size is not critical, within the limits that are common in high performance liquid chromatography, and a 0.4 mg sample is usually adequate. The resulting solution proceeds into the upstream end of column 11. In other embodiments, the solvent is a weak solvent (for convenience,
However, it is not essential, and a sample containing a solution of hydrocarbons, which is the same solvent as supplied to the pump 19) is introduced as a "slug" through the injection valve 13, which is
Other weak solvents from 19 will drive the passage through the column.

Liquid exiting the downstream end of column 11 is constantly monitored in UV detector 22 and mass sensitive detector 23. UV monitor detector 22 and mass sensitive detector 23 operate according to the principles described herein. The response of these detectors can be digitized and automatically converted to levels or proportions of various components in the oil sample.

Due to the lower retention of saturated hydrocarbons by aromatics due to fixed packing material in column 11, the response in the mass sensitive detector typically starts before UV absorption is detected, As the aromatic molecules pass through the mass sensitive detector, some aromatic hydrocarbon molecules pass through the UV detector at the same time and tend to overlap during the UV absorption period.

The diffusivity or elution rate of a molecule containing an aromatic ring as indicated by the speed of passing through the column 11 mainly depends on the number of aromatic rings in the molecule. Molecules with a single aromatic ring elute relatively quickly, and molecules with two or more aromatic rings elute more slowly. Therefore, by calibrating column 11 with molecules containing different numbers of aromatic rings, column 11
It is possible to confirm the eluted molecule by the time required to pass through. Calibration is suitably performed, for example, with toluene (one aromatic ring), anthracene (three fused aromatic rings) and coronene (six fused aromatic rings). Calibration can be performed with additional polycycles and / or different polycycles.

During operation of the method described herein, substantially all of the monoaromatic molecule elutes within a time span comparable to toluene, and the tricyclic molecule has a time comparable to anthracene after the time span of the monoaromatic molecule. Eluting into the span, the six-aromatic ring compound elutes after a time span of anthracene during a time span comparable to coronene. Molecules with the number of aromatic rings between toluene and anthracene and between anthracene and coronene elute after the time interval between each pair of molecules used for calibration.

When substantially all the saturated and aromatic hydrocarbon molecules are eluted from column 11 by the weak solvent and illuminated by the UV absorption and refractive index decreasing to their base value by the solvent alone, the strong solvent (ie, Solvent having a relatively high polarity) is flowed into the column at a progressively increasing rate by the pump 20, while the weak solvent is correspondingly progressively reduced by the pump 19 such that the overall volumetric rate of the solvent is substantially unchanged. Sent at speed. After a selected third time interval, no weak solvent is present and the only solvent that proceeds to the upstream end of column 11 is the strong solvent. 8.9-10.0 cal ^0.5 cm for strong solvent
^It has a solubility parameter in the range of ^-1.5 and is transparent to UV. A suitable strong solvent should be transparent to UV light at the lowest possible wavelength to facilitate calculation of oscillator strength. The strong solvent should have a polarity between toluene and carbon disulfide, and is suitably dichloromethane. Dichloromethane can include alcohol to increase its ability to elute polar high molecular weight molecules. Suitably the alcohol is 2-propanol and the strong solvent is 90% by volume.
It can consist of dichloromethane and 10% by volume of 2-propanol. In a variation of the apparatus of FIG. 2 described so far, pumps 19 and 20 were switched on with weak and strong solvents (eg, cyclohexane and dichloromethane), respectively.
Can be used to feed alcohol or other highly polar eluting material from respective third pumps (not shown) to mixing chamber 16 via tubes 17 and 18, respectively. A tube 18a can be present. Third
The pumps are microprocessor controlled, preferably in association with pumps 19 and 20, in a predetermined arrangement or program in a manner known in the art.

If the alcohol or other highly polar solvent denaturant was not introduced with the strong solvent during the third time period, it is introduced over the fourth time period (eg, at or near 5 minutes). In each case, alcohol or other highly polar solvent modifier is introduced at a constant increasing rate, and the rate for strong solvents is correspondingly reduced.

Only the denatured strong solvent is passed into column 11 for a fifth time period to elute highly polar molecules from the column. Elution of polar molecules is detected by both detectors. The polar molecules of a typical hydrocarbon sample containing asphaltenes, within a fifth time period of about 10 minutes due to the relatively fast decline in UV absorption 3-10 minutes after sending only the strongly denaturing solvent into the column It is virtually completely eluted.

When the elution of the polar molecule is substantially complete, the strong solvent is gradually replaced by a weak solvent (ie, 99.99% by volume cyclohexane with 0.01% by volume 2-propanol) over a sixth time period. Suitably, the sixth time interval may be in the range of 1 to 10 minutes.

The weak solvent may be replaced by first stopping the addition of the alcohol modifier to the strong solvent, and then gradually replacing the strong solvent with the weak solvent. The next hydrocarbon sample can then be passed through the injection valve 13 with the weak solvent through the column.

Referring now to FIG. 3, the upper graph 30 shows the change with time of the response of the substance passing through the mass sensitive evaporative light scattering detector 23; the lower graph 31 shows the response of the substance passing through the UV detector 22. The change with time of the UV oscillator strength is shown.

The time on the horizontal axis is indicated by an interval of 3 seconds or an increment (hereinafter also referred to as “channel”) from a reference time “0” which is 40 channels after the sample is injected.

The sample was 0.4 mg heavy Arab vacuum residue. Solvents were pumped by pumps 19, 20 at the same time in gradually varying proportions or individually, giving a constant solvent flow rate through column 11 of 1.0 ml per minute.

During the initial time before the reference time, only the weak solvent was passed through the pump 19 at the above-mentioned rate of 1.0 ml / min, and the light scattering signal and the UV oscillator strength were constant during this time. Only the weak solvent was supplied by the pump 19 through the injection valve 13 for 7 minutes from the injection of the hydrocarbon oil sample. Shortly thereafter, the strong solvent was gradually displaced at a uniform rate (ie, linearly over 2 minutes) to a weaker solvent. Then pump only strong solvent 19
Via the injection valve 13 for 4.0 minutes, at which time it was gradually replaced by a denaturing strong solvent for 0.1 minutes, and the flow was maintained thereafter for 12.9 minutes. In each case,
There is a time delay from the time passing through the injection valve 13 until, for example, the sample or each solvent reaches and passes through the column.

A 0.4 mg sample of the vacuum residue was injected into the injection valve 13 from the sample injection line 14 into the -40 channel at the reference time. Due to the time delay, none of the detectors showed any deviation from the stable baseline before the sample injection for the first 40 channels.
After 11 channels, the light scatter signal detected by detector 23 has one or more spaced apart responses including a sharp increase in response from baseline 32 to a maximum (point 33), followed by a gradual decrease to solvent alone. The change was interrupted by an increase in response. The light scatter signal was included as an internal standard and responded to the elution of 40 μg of benzo (α) anthracene indicated by peak 34. Elution of polar heteroaromatic species due to solvent change to dichloromethane was indicated by peak 35, and elution of strongly polar heteroaromatic species due to change to 90% dichloromethane, 10% isopropanol in solvent was indicated by peak 36. .

Referring to the UV oscillator strength graph 31, it can be seen that the increase in absorbance from the baseline began at about channel 15 and peaked at about channel 24 (point 37). The peak value of the absorbance was maintained for a short time, and then maintained at a height higher than the baseline indicating the aromatic hydrocarbon eluted at each specific time. At point 38 the response of the internal standard appears. In channel 219, which roughly corresponds to the complete displacement of the strong solvent for the weak solvent in the column, there is a sharp increase in UV absorbance, which rises to a peak based on the polar compound (point 39), followed by a relatively fast decline. Indicated. The small additional peak 40 corresponds to the elution of highly polar compounds in strong solvents.

An additional peak was observed and recorded when the strong solvent, dichloromethane, was denatured in the column by the addition of 10% by volume of isopropanol. Finally, the detector response returned to a value very close to the initial baseline at point 42, at which point data collection was stopped.

The relationship between solvent type variation in light scattering response and UV oscillator strength is as follows; the initial change in light scattering corresponds to the elution of saturated hydrocarbons and minor aromatics. The saturated hydrocarbon peaks at point 33, with the subsequent decrease in light scattering indicating a relatively complete elution of the saturated hydrocarbon and a related contribution from the eluted aromatic hydrocarbon. The relatively sharp increase in UV absorbance up to point 37 results in elution of aromatic hydrocarbons in weak solvents. Aromatic species with increasing numbers of rings subsequently elute from the column with a weak solvent, as indicated in part by internal standards. The highest point in the peak absorbance (point 3) begins shortly after the onset of the gradual transition from weak to strong solvent, and after the mobile phase composition changes to strong solvent only.
The spike in UV absorption reaching 9) is attributed to elution of polar compounds. Polar compounds are eluted relatively slowly and effectively (given their relatively high molecular weight and physicochemical properties) until they are substantially completely removed from the column by strong solvents.

Elution of the highly polar material as indicated by peaks 40 and 41 results in complete recovery of the oil injected into the column.

During the next 38 minutes of equilibrating the stationary phase in the column with the weak solvent (ie, 26-60 minutes from the moment of sample introduction), the initial properties of the stationary phase are regenerated and the second cycle of analysis can be performed with the next sample injection. Can be implemented by Thus, the total cycle time is 60 minutes. The total cycle time can be reduced by increasing the flow rate of the solvent through the column and / or by starting the introduction of the strong and denaturing strong solvent earlier.

The proportion of each hydrocarbon type or component in the sample converts the light scattering response to a linear function of total mass and the UV oscillator intensity to a function of the mass of aromatic carbon, as described herein, Obtained by integrating over the retention time interval. Components are defined by retention time intervals. Accordingly, saturated hydrocarbons are compounds eluted in the range of 9 to 16 channels, monocyclic aromatic hydrocarbons are compounds eluted in the range of 16 to 24 channels, and bicyclic aromatic hydrocarbons are compounds in the range of 24 to 40 channels. The three-ring aromatic hydrocarbon is eluted with
As those eluting in 40-75 channels, the four-ring aromatic hydrocarbons elute in 75-200 channels, and the weakly polar components elute in 200-300 channels,
And strongly polar components can be defined, determined, or considered to elute in the 300-400 channel. The use of model compounds to define the components is described here (eg with respect to FIGS. 1 and 2).

Column quality is measured by chromatography of a "cocktail" containing toluene, anthracene and coronene in cyclohexane. The column is tested isocratic with cyclohexane and 0.01% 2-propanol. The volume coefficients are 0.1, 0.5 and 2.0 for toluene, anthracene and coronene, respectively, and the volume coefficient is the amount of retention volume minus void volume divided by the void volume of the stationary packed phase in column 11. It is observed that chromatography of this mixture gives a good indication of the quality of the column. If the column becomes contaminated with retained polar compounds or ages excessively, the capacity factor will increase. Column of different manufacturers, even at their all nominally Enuita ₂ bonded silica, is also some that show widely different capacity factor and separation performance. A summary of capacity factor data for adsorbents from different sources is given in Table 2.
Given inside. Columns with a volume coefficient for coronene greater than 5 gave poor separation due to low yields of aromatic and polar components.

In this operation, the separation carried out cyclically with a load comparable to that of the preparative case, gave good selectivity for microcondaughton residual carbon (MCR), a measure of the tendency to coke formation, and excellent selectivity for metalloporphyrins. Shows selectivity.

In practical tests of the disclosed method, cold lake bitumen was separated into 65% non-polar compounds (saturated and aromatic hydrocarbons) exhibiting an MCR of 2.7 and 37% polar compounds having an MCR of 34% by weight. All bitumens had an MCR of 14.3% by weight. Heavy Arabian vacuum resid has a non-polar fraction with an MCR of 9 53-58% and a yield of 43-47% and 45-
Separated to a polar fraction with 47% MCR. 23 total residual oil
It had a weight percent MCR. There was no metallovolphyrin detectable by visible spectroscopy in the non-polar fraction (≦
1 ppm). These data indicate that difficult-to-process components (i.e., substances that may be detrimental to the quality of the hydrocarbon sample and / or adversely affect subsequent use) are enriched in the polar fraction, as well as non-polar and polar 4 shows that high yield selective separation of compounds was achieved. The operation retains aromatic hydrocarbons as a function of their degree of conjugation. In all assays using the methods and apparatus of the present invention, 99 +% of the saturated, aromatic, polar molecules and asphaltenes fractions are recovered within a relatively short analysis cycle (eg, 30 minutes).
This is an open column, eg, incomplete sample collection, typically only 95%, requires relatively large samples (eg, on the order of 3 g) and relatively long sampling times (eg, about 8 hours) Contrast with that used to perform ASTM D-4003 conventional method.

The reproducibility of the stationary phase was shown in detail in practical tests.
Each individual column 11 was used at a 4 mg load for well over 100 analysis cycles before significant loss of performance was observed. The described chromatographic methods and apparatus can easily be adapted for automatic operation. FIG. 2 and FIG.
30 complete analysis columns listed as non-limiting examples in connection with the figure
Minutes, but it can take a distinctly different amount of time, within the whole time of each cycle, running the pump on weak and strong solvents, the timing of injection of oil samples and UV absorption data (and if necessary All recordings of mass detector data) can be controlled by automatic sequencing equipment. Since such automatic sequencing devices are well known and readily available from commercial manufacturers,
Moreover, a description thereof will not be provided here, as it is merely a common item of equipment without forming a direct part of the present invention.

The described chromatographic methods and apparatus may be used to evaluate hydrocarbon mixtures or to control or optimize methods for purifying or upgrading hydrocarbon feeds, e.g., fractionation of hydrocarbon feeds, at least a portion of the feed may be treated. It can be used for the preparation of catalytic cracking feeds which are catalytically hydrogenated to reduce difficult properties, and especially for solvent purification (eg de-history) of hydrocarbon mixtures.

Comparative Example Journal of Chromatography (1981) 20
6, High-performance liquid chromatography (HPLC) technique which is said to be capable of analyzing vacuum residues (boiling range above 535 ° C) for saturated, aromatic and polar compounds in C. Bollet et al. Is described. The technique uses two operations. In a first operation, saturated hydrocarbons are separated from saturated hydrocarbons and polar compounds using a 10 μm silica-bonded alkylamine stationary phase in a column 20 cm long × 4.8 mm ID. The mobile phase used was n
-Hexane, which states that cyclohexane should be used as the mobile phase to avoid asphaltene precipitation for asphaltene-containing samples. The article does not state that there is complete recovery of the sample in the eluent, but it could be taken to mean that the article actually has 100% sample recovery.

According Boretto addition of the second operation to be performed using a more polar solvent separation from the polar compounds, saturated hydrocarbons and aromatic compounds, a chromatographic column packed with functionalized silica NH ₂ Merck (Merck ) Lichrosorb, 85% cyclohexane and
The mixture was equilibrated with a solvent consisting of 15% chloroform at a flow rate of 2.0 ml / min. Arabian heavy vacuum distillation residue (950+ ゜
(F, 510 + ° C.) 120 μg were injected into the column in 20 μ of cyclohexane solution. Detection was by monitoring UV absorbance at 254, 280 and 330 nm. The resulting chromatogram (at 280 nm) is shown in FIG. 4a, showing the dilution of saturated and aromatic hydrocarbons. The flow was then reversed (backflush). The next 10 polar compounds
Eluted over minutes, by which time a stable baseline had been reached. This is Figure 4b (UV absorbance monitored at 280nm)
Is shown in The sharp peak reported by Borett et al. Was not observed. This completes the analysis of Borett and others.

Comparing the method described by Borrett et al. With the method described here, the Borlett et al. Method indicated that considerable amounts of sample material, mainly polar compounds,
In the column while recovering 100% (or substantially 100%).
% Recovery) is achieved by this method.

To indicate that polar compound recovery was incomplete,
And as an example of one way of carrying out the method of the present invention, a stream of 90% dichloromethane and 10% isopropanol was introduced in a solvent gradient over 10 minutes with the flow reversed in its normal (forward) direction. The absorbance was measured for 20 minutes, with about 8 additional peaks due to the polar compounds strongly retained during that time.
(FIG. 4, showing absorbance at 280 nm).

Thus, Borret et al. Leave some polar material on the column. The absorbance in each of FIGS. 4a-4c was integrated over time to provide a measure of how much material was removed from the column at each step. The results are as follows: The amount of material left by the Borett et al. Method on the column is about 12% of the vacuum residue sample. This results in some problems which are avoided or overcome by the methods disclosed here:-The material left on the column is not properly evaluated in the composition analysis.

-The material left on the column creates adsorption sites for the next analysis, giving unreproducible results.

-The material left on the column can effectively disrupt the flow, resulting in high back pressure and loss of operation.

In order to achieve good recovery of the resid from the HPLC column, the solid sorbent material must be functionalized to shield inorganic oxides and hydroxyls. The final elution solvent must be soluble in asphaltenes and have hydrogen bonding and / or high polar functionality to neutralize the surface activity of the adsorbent. A preferred combination is to use a mixture of dichloromethane and isopropanol with silica functionalized with a primary amine as adsorbent, where isopropanol is in the range of 1-50% as the final solvent in oil elution. Of which are most preferably present at a volume concentration of 10%. This solvent can be introduced downstream or backflush. What is important is the solubility and polarity of the solvent, not the flow method.

In a variant of the separation, a three-pump system is used. First
The pump supplies cyclohexane, the second pump supplies dichloromethane, and the third pump supplies isopropanol. The feed rate will change over time. Cyclohexane is used to elute saturated hydrocarbons followed by aromatic hydrocarbons, with weakly polar compounds being eluted next with dichloromethane, finally strong polar molecules being eluted with dichloromethane and finally strong polar molecules being 10% in dichloromethane. Eluted with isopropanol. The exact solvent composition program is not critical for obtaining information because it can change the component assignments.
It is important to increase the solubility parameter of the solvent as the chromatography proceeds so that oil components of progressively higher solubility parameters can be desorbed and measured. Preferably, the solubility parameter of the solvent is increased gradually rather than as a step change. However, step changes can be used and are within the scope of the present invention.

The ability to accurately analyze residual oils is one of the more important advantages of the disclosed method over the prior art. However, there are some other advantages of this method compared to the prior art of Borette et al .:-Instead of two operations, only one-stage operation is used, simplifying the method.

-Aromatic hydrocarbons are separated by the number of fused aromatic rings, thus providing additional compositional information.

The new detection sequences described allow the quantification of the oil component without having to obtain a response factor for each compound type.

In each of the foregoing purification or quality improvement methods (ie, distillation, solvent purification and catalytic cracking or coking), this chromatographic method and apparatus can be used to detect unacceptable levels of individual types of hydrocarbons or other substances. Based on such detection, a signal may be induced or adjusted that may adjust the operation of the process and / or the steps associated with the process to reduce undesired levels of hydrocarbons or other substances below unacceptable levels. Generated. Thus, referring sequentially to each of the foregoing methods, the following are the primary objects and methods achieved by the present invention: (1) Distilled hydrocarbon feed comprising asphaltene material (hereinafter referred to for short as "asphalten"). A number of factors can cause excessive entrainment or carryover of asphaltenes in distillate fractions, especially gas oil fractions, in the distillation of distillates. Such factors include, but are not limited to, excessive stripping distillation rates; excessively high heat input to the bottom recycle stream; excessively high feed rates.

Since the presence of excess asphaltenes in the distillate is usually detrimental to the quality of the distillate and / or its subsequent use, the use of the disclosed apparatus and method for detecting excess asphaltenes optimizes the operation of the distillation column. Means an important step forward.

In accordance with this aspect, a 0.4 mg sample of gas oil from the distillation column is injected at a suitable standard temperature (eg, 25 ° C.) via valve 13 into the apparatus of FIG. 2 and the chromatographic method described with respect to FIGS. Hang on the graph. Asphaltenes are highly polar and their concentration in gas oil samples is dependent on the UV oscillator strength curve during elution with strong solvents (eg, between points 38-42 in FIG. 3).
It can be easily confirmed from the area under. The area under the UV oscillator strength is determined by well-known routines for doing so, and one or more that reduce asphaltene entrainment in the distillation column if the area exceeds an acceptable area. Known means can be implemented. The first available measure is to reduce the speed of the stripping steam, since reducing the feed rate to the column is usually undesirable. The reduced heat input to the column can be compensated for by adjusting the asphaltene carryover by increasing the bottom reflux temperature rather than the feed temperature, as known to those skilled in the art. Adjustment of the operation of the distillation column by asphaltenes as determined by the disclosed chromatographic method can be performed by manual adjustment, by an operator based on the output of the chromatograph, or automatically based on the output of the chromatograph. .

(2) Solvent Purification In solvent purification, the feed material is brought into intimate contact with a solvent that has a selective solubility or affinity for a particular type of material in the feed, and the resulting solution is separated from residual raffinate. In solvent deprivation, a feed containing an asphaltenic substance (hereinafter referred to as asphaltenes for brevity) is mixed with a short-chain n-paraffin, such as n-propane, which is completely miscible with non-asphaltene but immiscible with asphaltenes Mixing, whereby the asphaltenes form a second heavy phase, which can be removed by a suitable separation method such as decantation. If the deasphalting operation is performed at an excessively high rate for the separation of asphaltenes from the solvent-oil solution occurring in the effective apparatus, asphaltenes will be entrained in the deasphalting solution.

To monitor the asphaltene content of the dehistory solution,
A sample of the dehistory solution was passed through a chromatographic apparatus of the type described with reference to FIG. 2 at the appropriate standard temperature, and the area under the UV oscillator intensity curve during elution with strong solvent (point 38 in FIG. 3).
(Corresponding to the area under curve 31 of ~ 40) is assayed by any known technique. If the area exceeds the area indicating an acceptable amount of entrained asphaltenes, the feed rate is reduced, either manually or automatically, until an acceptable asphalt tent level is reached.

(3) Preparation of the catalytic cracking feed [and / or improvement of the quality of the gas oil] In particular, the catalytic cracking feed material, and generally the gas oil, comprises molecules and / or polar molecules containing various proportions of one or more aromatic rings. including. Polyaromatic molecules tend to withstand decomposition while passing through the catalytic cracker, and thus tend to be enriched in decomposition products, while polar molecules decompose during decomposition to form relatively large carbonaceous materials. There is a tendency for deposits to be deposited on the catalyst, thereby impairing the latter's catalytic activity.
In addition, fractions containing gas oil and other polycyclic aromatic structures are:
It is desirable to be able to control the levels of polyaromatic and polar molecules in gas oils and other hydrocarbon distillates, which tend to produce smoke when combusted and at least for the above considerations.

One way in which the enrichment of distillate fractions, such as asphaltenes, resins and polyaromatic ring molecules in gas oil, can be controlled is to control the cut points of the fraction during distillation, and the way to do this is to It has already been described in connection with it. When the concentration of asphaltenes and polyaromatic rings in the distillate fraction from the distillation apparatus is found to exceed the desired maximum concentration using the described chromatographic apparatus and methods, the asphaltene and polyaromatic ring molecules are identified. Signals indicative of UV absorption properties and their excess concentrations are derived and used to control the operation of the distillation apparatus until the concentration of such molecules falls to acceptable levels in the distillate fraction.

In the context of catalytic cracking, it reduces the tendency of aromatic molecules (including polyaromatic molecules) to be enriched in decomposition products1
One method is to hydrogenate the resulting naphthene structures (ie, cycloparaffin structures) as they decompose relatively quickly. Hydrogenation also tends to reduce the concentration of polar compounds. Hydrogenation is promoted by a suitable hydrogenation catalyst, such as a combination of Group VI and VII metals on a low acidic support such as alumina (eg, Mo and Co).

In relative terms, hydrogen is an expensive commodity, and it is therefore highly desirable to hydrogenate only a select proportion of the hydrocarbon materials which, from an economic standpoint, result in the formation of cracking products of acceptable quality. The proportion to be hydrogenated may be directed to the hydrogenation unit, or the entire feed may be passed through the hydrogenation unit to vary the hydrogenation conditions to achieve the desired ratio of hydrogenation, or both of the above means may be used to an appropriate degree. It can be selected by combining. Generally speaking, catalytic hydrogenation of polyaromatic molecules results in hydrogenation of only one of the aromatic rings in the molecule at a time per hydrogenation. The hydrogenated ring is decomposed by passing through a catalytic cracker, and the resulting molecule having one less aromatic ring is further decomposed until the content of difficult-to-process aromatic molecules in the decomposition product is reduced to an acceptable level. It can be hydrogenated to facilitate cracking of additional saturated aromatic rings in each subsequent pass through the catalytic cracker.

Catalytic hydrogenation of polar molecules is also performed to the extent necessary to increase the quality of the hydrocarbon cut to a level suitable for subsequent use, for example, catalytic cracking.

By way of example, reference is now made to FIG. 5, which illustrates the key features of a catalytic hydrotreater 50 that embodies process control in a block chemical engineering flow diagram. In this non-limiting example, the apparatus is to upgrade the catalytic cracker feedstock, but it will be recognized by those skilled in the art that it can be used to upgrade the feedstock for other purposes.

The untreated feed (eg, gas oil from a vacuum distillation column) proceeds via line 51 to a sampling point 52 where the main stream proceeds via line 53 to a catalytic hydrogenation facility, hereinafter referred to as “hydrotreater” 54 for brevity. . Alternatively, the hydrotreater 54 may leave via line 59 and the product passing via line 60 to a catalytic cracker (not shown) may be sampled via line 57 and valve 56.

An automatic high performance liquid chromatograph (HPLC) analysis and control device embodying a device of the type described in particular with respect to FIG.
61 analyzes a sample of the raw feed from line 55 or the processed feed from line 57 and adjusts the operation of hydrotreater 50 so that the feed in line 60 is of acceptable quality. The used sample is discharged via a line 62.

The HPLC device 61 has at least the following (among others) regulating effects: (a) the flow rate of the feed through the hydrotreater and therefore the residence time or space velocity; (b) in the hydrotreater 54 determined by the hydrogen control device 63 Ratio of hydrogen to feed. As already mentioned, hydrogen is relatively expensive and it is preferred to find an economic balance by comparing the cost of using hydrogen with the increased value of the hydrogenated feedstock. The hydrogen controller 63 plays a role in achieving this economic balance.

(C) The operating temperature of the hydrotreater 54 determined by the temperature controller 64. High operating temperatures increase the removal of heteroatoms (eg, nitrogen) in polar molecules that tend to reduce the activity of the catalytic cracker, while lower operating temperatures increase the saturation of aromatic rings in the molecules involved. An economic balance should be found between the value of the treated feed with reduced polar molecular content and the value of the treated feed with low saturated aromatic ring content. Temperature controller 64 plays a role in achieving this overall balance.

Feed speed, hydrogen controller 63 and temperature controller 64
Can be adjusted by manual operation or automatic operation or a combination of manual and automatic operation, respectively. When automatic control of one or more adjustments is used, control can be by means of a conventional type of computer (not shown). A suitable program for the control computer to manage some or all of the operation of the device 50 can be devised by a qualified programmer. The control computer and its software,
Both are within the current state of the art and are not described as they do not have a direct bearing on the invention as set forth in the appended claims.

The operation of the catalytic hydrotreater 50 will now be described with particular reference to the preparation of an improved catalytic cracker feedstock from feed obtained from a vacuum distillation column (not shown).

The braided feed in line 51 is first passed at least a major portion to the hydrotreater via line 53 and then to the catalytic cracker feed line 60 via line 59. line
The feed in 55 and the product in line 57 are passed periodically (e.g., once every 60 minutes) and alternatively through an HPLC apparatus 61 in which saturated hydrocarbons, mono- and polyaromatic ring molecules and polar Molecules (the latter containing heteroatoms such as nitrogen and oxygen) are analyzed. Analysis by HPLC apparatus 61 is generally performed in the manner specifically described with respect to FIGS. From the analysis in device 61, signals indicative of the composition of the coarse feed are derived in signal lines 67 and 68.

Information about the feed can be used with "feed-forward" control intent to adjust the best conditions for flow rate, temperature and hydrogen pressure in the hydrotreater.

If the product in line 59 has an unacceptably high content of polycyclic aromatic and polar molecules, hydrogen controller 63
It acts to increase the partial pressure of hydrogen and the ratio of hydrogen to crude feed in the hydrotreater 54 which receives a programmed cost constraint signal for the device 63 provided via the signal line 69 from the control computer.

A common adjustment for the temperature controller 64 is one suitable for the saturation of the aromatic nuclei, i.e., a relatively low hydroprocessing temperature in the range of about 300-510C. But the usual adjustment is signal line 70
Via the control computer reaching the temperature controller 64 via the controller to adjust the heteroatom content (ie polar molecule content) of the crude feed to an acceptable level corresponding to an acceptable level of aromatic ring saturation in the crude feed. Increase the hydrotreating temperature to lower.

Adjustment of valve 56 may be performed by human intervention or by a control computer (signal line) for flow and frequency to be analyzed.
It can be changed by the signal from 71).

Some additional illustrations of the disclosed method are then given in the following non-limiting examples.

Example 1 Production of Lubricating Oil-Based Feedstock The purpose in the production of lubricating oil-based feedstock is mainly to separate molecules from feedstocks having good lubricity, including high viscosity index. Saturated hydrocarbons and aromatics not exceeding one ring are most desirable. Two important steps in the manufacture of heavy lubricating oil feedstocks of the type known as bright stock are: de-residing the vacuum resid with propane to produce a de-history oil and condensing the de-histored oil with a polar solvent such as phenol Extracting the ring-aromatic hydrocarbon and the resin to produce a raffinate. The asphaltenes produced during the first stage and the aromatic-rich extracts produced during the second stage are by-products and have other uses. Monitor the molecular composition of each stream using the described HPLC technique and adjust the process conditions to achieve the highest yield of raffinate within quality specifications based on the molecular composition.

Samples of each process stream were obtained and analyzed as described in FIGS. An evaporative light scattering detector was used. It was linearized according to equations (2) and (3) by measuring its peak response to known concentrations of vacuum gas oil. The retention level limit is defined by the model components. The integration level of each component is shown in Table 3 in terms of% by weight of all the samples.

Observation of the data suggests a process change, which will be apparent to those skilled in the manufacture of lubricating oil-based feedstocks. The asphalt stream rejected from the de-history stage contains 15.7% saturated hydrocarbons. Some or all of these could be included in the de-historized oil by lowering the temperature in the de-historizer and increasing the treatment ratio (ie, solvent to feed ratio). De-historic oil contains 3- and 4-ring aromatic hydrocarbons, which are below the detection limit, but which are concentrated in the extract. The extraction step consists of two rings from the raffinate, three
Although it was effective in removing ring and 4-ring aromatic hydrocarbons,
Traces of resin (polar compounds) remained, and some saturated hydrocarbons were also removed. The selectivity of this separation could be improved, for example, by increasing the throughput. Process changes are likely to be made by balancing the cost of the change versus the benefit in improved product quality or quantity.

Example 2 Production of Catalytic Cracking Feed Material Heavy vacuum gas oil and heavy coker gas oil are produced by vacuum distillation and fluid coking, respectively. These streams are found to be too high in sulfur, nitrogen, 3+ ring aromatics and polar compounds for effective catalytic cracking. Thus, they are mixed and subjected to a hydrotreating process in which they are sequentially passed through two reactors. Both reactors are charged with a commercial Co-Mo alumina hydrotreating catalyst. The feed is mixed with hydrogen gas at a partial pressure of 1200 psi (8278 kPa) and the average bed temperature is
705 ° F (373.9 ° C). Residence time is approximately 2 in each reactor
2 minutes.

The molecular composition of the feed is compared to the products of the first and second series reactors by the HPLC method of the present invention. The separation is effected by the method described in connection with FIGS. The detector is a UV diode array spectrophotometer. The integrated oscillator strength is calculated as in equation (1) above,
It is converted to the weight percent of aromatic carbon by the correlation shown in FIG.
The composition of each stream is given in Table 4. It is clear that the feedstock is upgraded across each reactor. Basic quality improvement results in the content of 3+ ring aromatic hydrocarbons and polar compounds, which is only about 1/2 of the starting level. 1
Ring and bicyclic aromatic hydrocarbons are produced by hydrogenation of polynuclear aromatic hydrocarbons.

The useful information in Table 4 can be used to adjust the process.
If the product level of the 3+ ring aromatic hydrocarbon plus polar compound is below the control point determined to provide a good catalytic cracking feed, the plant operator can, for example, reduce the residence time through both reactors or Either of the total bypass of the second reactor can be determined. Another common method of control would be to change the hydrogen partial pressure and / or temperature.

The invention described in the claims is not limited to the particular embodiments disclosed. Furthermore, features described in connection with one aspect may be used in other aspects without departing from the invention as set forth in the claims. In addition, the disclosed UV detection technique to derive integrated oscillator strength can be used alone in HPLC, to determine the level of aromatic carbon present, or in combination with mass sensitive measurement techniques (using at least weak and strong elution solvents). T) can be used to measure the levels of saturated hydrocarbons, aromatic hydrocarbons and polar compounds in oil samples.

[Brief description of the drawings]

In the drawings, which are referred to by way of example in the description of the invention, FIG. 1 shows the eluent derived from the aromatic carbon (wt%) (horizontal axis) versus the integrated oscillator strength in various hydrocarbon oil samples by NMR. FIG. 2 is a regression analysis graph of the expected total aromatic carbon (% by weight) of FIG. 2; FIG. 2 is a schematic diagram showing one embodiment of an apparatus used by one method for practicing the method of the present invention; FIG. 4 is a graph showing composition data on the vertical axis versus time on the horizontal axis for an analysis performed using the apparatus of FIG. 2; FIG. 4 shows borettes in graphs (a), (b) and (c). 5 shows the absorbance vs. time of the eluent recovered during a repetition of the method described in the Journal of Chromatography (1981), 206 , 289-300; FIG. A method embodying the apparatus used by one method of performing the method and the method It is a chemical engineering flow sheet of the adjusting device.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 30/88 G01N 30/74 JICST file (JOIS) WPI (DIALOG)

Claims (5)

(57) [Claims] 1. A method for refining or upgrading a petroleum hydrocarbon feed by catalytic cracking, wherein a sample of the hydrocarbon oil produced during the process is: Contacting and passing a chromatographic stationary phase over a time interval to retain the components of the hydrocarbon oil on the stationary phase; (b) after step (a), fixing the various retained components of the oil to the stationary phase Passing the mobile phase through the stationary phase for a second time interval to elute from the phase at different time intervals, and recovering the mobile phase in contact with the stationary phase along with components eluted from the stationary phase; (c) recovery Mobile phase, at least partially from about 200 to about 4
Irradiating with a UV light having a wavelength range in the range of 00 nm for a sufficient time period that the recovered components in the recovered mobile phase are exposed to said irradiation, said mobile phase being a UV light in said wavelength range. (D) monitoring the absorbance of the UV light by the illuminated component over the wavelength range and obtaining an integral of the absorbance over the wavelength range as a function of photon energy; and e) measuring the magnitude of the integral obtained above for at least one selected time period corresponding to the elution of one or more components, chromatographically by chromatographic analysis of a hydrocarbon oil comprising: Analyzing the presence level of at least one component in the oil and controlling the operation of the process based on the presence level determined for the at least one component. 2. The method according to claim 1, wherein the control of the operation of the process is such that the value of the presence level of the at least one component does not exceed a predetermined value. 3. A method for refining or upgrading a petroleum hydrocarbon feed containing asphaltene material by catalytic cracking, wherein said feed is separated into a fractionator having a temperature and pressure gradient in order to separate the feed into components by boiling range. Through which the components are recovered from respective areas of the fractionator,
In addition, discontinuous samples of the gas oil fraction containing gas oil components that boil in the gas oil boiling range recovered from the gas oil recovery area of the apparatus are taken from the recovered gas oil fraction at intervals, and (a) hydrocarbon oil and carrier phase, respectively. Contacting the mixture with a chromatographic stationary phase over a first time interval to retain the components of the hydrocarbon oil on the stationary phase; (b) after step (a), various retentions of the oil The mobile phase is passed through the stationary phase for a second time interval in order to elute the separated components from the stationary phase at different time intervals, and the mobile phase in contact with the stationary phase is recovered together with the components eluted from the stationary phase. (C) removing at least a portion of the recovered mobile phase from about 200 to about 4
Irradiating with a UV light having a wavelength range in the range of 00 nm for a sufficient time period that the recovered components in the recovered mobile phase are exposed to said irradiation, said mobile phase being a UV light in said wavelength range. (D) monitoring the absorbance of the UV light by the illuminated component over the wavelength range and obtaining an integral of the absorbance over the wavelength range as a function of photon energy; and e) measuring the magnitude of the integral obtained above for at least one selected time period corresponding to the elution of one or more components, and analyzing by chromatographic analysis of the hydrocarbon oil comprising: ,
The method as described above, wherein a signal is generated indicating the amount of asphaltenic material present in each sample and used to adjust the operation of the fractionator so that the amount of polar components in the gas oil component is maintained below a predetermined amount. 4. A process for refining or upgrading a petroleum hydrocarbon feed by catalytic cracking, wherein the feed is passed through a catalytic cracking unit to convert the feed to cracked products containing the upgraded hydrocarbon material. Taking discontinuous samples of the feed going to the catalytic cracking unit at intervals; and (a) passing a mixture of a hydrocarbon oil and a carrier phase into contact with a chromatographic stationary phase for a first time interval; (B) after step (a), displacing the mobile phase with the second time interval to elute the various retained components of the oil from the stationary phase at different time intervals. Recovering the mobile phase in contact with the stationary phase together with the components eluted from the stationary phase; and (c) collecting at least a portion of the recovered mobile phase from about 200 to about 4
Irradiating with a UV light having a wavelength range in the range of 00 nm for a sufficient time period that the recovered components in the recovered mobile phase are exposed to said irradiation, said mobile phase being a UV light in said wavelength range. (D) monitoring the absorbance of the UV light by the illuminated component over the wavelength range and obtaining an integral of the absorbance over the wavelength range as a function of photon energy; and e) measuring the magnitude of the integral obtained above for at least one selected time period corresponding to the elution of one or more components, and analyzing by chromatographic analysis of the hydrocarbon oil comprising: ,
Generating a signal indicative of the amount of the polar component and the aromatic component having at least three rings, the signal corresponding to an amount of the aromatic component having at least three rings and the polar component exceeding a predetermined amount; When and / or when appropriate, the feed is mixed with a high quality feed, or subjected to catalytic hydrogenation, or both mixing and hydrotreating, to increase and decrease the magnitude of the signal. The method wherein the strength of the catalytic hydrotreating is respectively increased and decreased accordingly. 5. A petroleum hydrocarbon comprising an asphaltenic substance, an aromatic component containing at least three conjugated aromatic rings, a polar component, and an undesirable contaminant selected from a mixture containing at least two of said contaminants. A process for purifying and upgrading a feed by catalytic cracking, comprising mixing a stream of selective purifying agent under selective purifying conditions and, from the resulting mixture, comprising (i) a low content of polar and aromatic components. (Ii) separately recovering a stream of a mixture comprising a solvent and at least one of said contaminant components, wherein a discrete sample of the raffinate stream is provided at each of: (a) A mixture of the hydrocarbon oil and the carrier phase is passed over the first time interval in contact with the chromatographic stationary phase to retain the components of the hydrocarbon oil on the stationary phase. (B) after step (a), passing a mobile phase into contact with the stationary phase for a second time interval to elute various retained components of the oil from the stationary phase at different time intervals. Recovering the mobile phase in contact with the stationary phase together with the components eluted from the stationary phase; (c) recovering at least a portion of the recovered mobile phase from about 200 to about 4
Irradiating with a UV light having a wavelength range in the range of 00 nm for a sufficient time period that the recovered components in the recovered mobile phase are exposed to said irradiation, said mobile phase being a UV light in said wavelength range. (D) monitoring the absorbance of the UV light by the illuminated component over the wavelength range and obtaining an integral of the absorbance over the wavelength range as a function of photon energy; and e) measuring the magnitude of the integral obtained above for at least one selected time period corresponding to the elution of one or more components, and analyzing by chromatographic analysis of the hydrocarbon oil comprising: ,
Generating a signal indicative of the amount of the contaminant, which is used, directly or indirectly, to vary the purification conditions such that the amount of the contaminant in the raffinate is maintained at or below the selected amount;
The method.