JPH02310469A - Method and apparatus for chromatographic analysis of hydrocarbon and hydrocarbon refining operation using the same - Google Patents

Abstract

PURPOSE: To provide a simple accurate device covering wider range by analyzing a compound mixture with a liquid chromatography. CONSTITUTION: A mixture of hydrocarbon oil and support phase is passed to make contact with a chromatograph fixed phase over a first time interval to hold the component of the hydrocarbon oil on the fixed phase. Thereafter, a movable phase is passed to make contact with the fixed phase over a second time interval and the movable phase contacted with the fixed phase is recovered together with a component fused out of the fixed phase. Then, the recovered movable phase is irradiated by at least one portion of UV ray having about 200 to about 400nm of wave length range over a time sufficient for irradiating the recovered component in the recovered movable phase. the extinction degree of the UV ray by the irradiated component is monitored over the wave length range and the integration of the extinction degree is obtained as a function of photon energy crossing the wavelength range. The size of the obtained integration is measured during at least one selected time corresponding to the fusion of one or more component.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Disclosure The present invention relates to a method for the chromatographic analysis of hydrocarbon oils, an apparatus therefor, and a method for purifying or improving hydrocarbon feeds using said method and apparatus for chromatographic analysis. . The present invention relates in particular to a method for determining the level of components present in hydrocarbon oils, in particular aromatic hydrocarbons.

Chromatography is a well-informed and widely used laboratory technique for the separation and identification of components of fluid mixtures, e.g. solutions, that relies on the different relative affinities between a stationary phase and a 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 packed substantially uniformly into a tube to form a column of immobilized material. The mobile phase can be the fluid under study, or more usually a solution of the fluid under study. The solvent used in the solution is usually passed through a column of solid stationary phase, followed by a small sample containing a solution of the fluid under study, and then only the solvent is passed through the column.

Components of the fluid have different affinities for the stationary phase and are therefore retained in different regions along the length of the column for different times. It is clear that the affinity for some components is small and virtually non-retentive, while the affinity for other components is large and the component is exposed to the potential elution characteristics of the solvent as it is introduced into the column. , it will not be recovered from the column even 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.

Petroanalysis
During Section 81.9, the hydrocarbon mixture mixed with the solvent produces an eluate that is collected from the outlet end of the chromatographic column, which contains the following types of molecular species: saturated hydrocarbons (e.g. paraffins and naphthenes). ), olefins and aromatic hydrocarbons, in that order.

(Generally) Residual species that are polar compounds have a relatively high affinity for solid chromatographic materials, interrupt the flow of the solvent, and in return have a relatively high affinity for, e.g., heteroaromatic compounds. It can only be completely recovered within a reasonable time by substituting a different solvent with a Said different solvents are passed in a direction opposite 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. The change in solvent from the first solvent, pentane, to the second solvent, methyl t-butyl ether, resulted in the use of two different eluent detectors, one using refractive index and the other using ultraviolet absorbance at 300 nm. to require.

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 stationary phase of the column. .

Journal of Liquid Chromatography (J
our own of Liquid Chrot＊at
(2), 229-242
(1980), hydrocarbon mixtures containing asphaltenes are simply separated by filtration by mixing the mixture with hexane and subjected to chromatographic analysis after precipitation of the asphaltenes, which is determined by gravimetry.

A hexane solution of the residual hydrocarbons was then dissolved in μm Bondabac (
Bondapak ) -N Hz particles are passed through a column where it is separated into an eluent containing first saturated hydrocarbons and then aromatic hydrocarbons, as determined by the refractive index of the eluent. The resin retained on the column is batter flushed from the column and determined by the difference. The separation properties of the column are maintained for repeated retention times by flushing it with a 1/1 methylene chloride/acetone solution after every 20 samples and then regenerating with methylene chloride and hexane. Changes in the refractive index of the eluent indicating the presence of each species are determined by Hewlett-Paracard (Hewlett-Paracard) using the so-called "zero" type method.
Lett-Packard) 3354B computer and correlated with the absolute abundance of the species. The disadvantages of this method are: (1) Asphaltenes are heavier than chromatography! (2) backflushing is used and all substances in the sample fed to the column are measured as evidenced by the stated need for periodic column cleaning; is not recovered in the eluent (further reference to this significant problem will be made later); (3) if the refractive index detector used
It has a variable response for aromatics and resins and therefore cannot give a universal response for a given mass independent of the nature of the sample of feedstock being analyzed.

Journal of Chromatography
lof Chron+atograph31), 20
6 (1981) 289-300, Boll
et) et al., describe a rapid high performance liquid chromatography technique for separating heavy petroleum products into saturated, aromatic and polar compounds. NH, bound silica [
“Lichrosorb NHz
A column containing a stationary phase of J) is used. Two chromatographic analyzes are required to determine the composition of the sample. In the first analysis, saturated compounds are separated from aromatic and polar compounds using hexane or cyclohexane as the 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 the mobile phase. The eluent is monitored for saturated, aromatic and polar compounds by differential refractive index measurements and for polar compounds by ultraviolet photometry. The proportion of saturated and polar compounds can be determined by these monitoring techniques, and the proportion of aromatic compounds is said to be found by difference. However, the method is similar to all other reports of high performance liquid chromatography (HPLC) for the analysis of samples of heavy hydrocarbon oil mixtures, as well as a means for quantitative and feedstock-independent detection and monitoring. Limited by lack of method. Therefore, the refractive index (R1) and the ultraviolet (UV
) for both the detector and the ``response factor'', which separates the sample of the feedstock on a large scale known as ``semi-preparative liquid chromatography'', and then the recovered analytes [for chromatographic separation. After removal of the solvent(s) added to the sample, it must be derived by weighing gravimetrically. The response factor depends on the nature of the feedstock and its boiling range, so it is essential to perform a relatively large scale separation in order to obtain accurate results in HPLC analysis.

Therefore, the potential benefits of speed and high resolution possible with HPLC have not heretofore been fully realized in practice.

The method of Bollett et al. is compared to the method of the present invention in the comparative examples provided below.

Klevens and Platt
), Journal of Chemical Physics (J
, Che+w.

See also Phys, ), Earthworks: 470 (1949). Similarities have been reported in the total oscillator strength for electron transfer of cata to fused aromatic hydrocarbons. However, that paper is not related to HPLC analysis; it uses a UV detector operated in a specific wavelength range to
P2 shows that C can be used to derive an integral oscillator intensity output for quantifying aromatic carbon in petroleum and shale oil charges.
Do not know or suggest. Furthermore, Katar condensed aromatic hydrocarbons constitute only a small fraction of the various aromatic hydrocarbons in hydrocarbon feedstocks, such as petroleum. Other aromatic compounds are also commonly present in the hydrocarbon charge, including para-fused aromatics, alkyl aromatics, and thiophene aromatics, which behave spectroscopically differently than Kattar-fused aromatic hydrocarbons.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple, more extensive and more accurate method and apparatus for the analysis of mixtures of compounds, especially, but not exclusively, mixtures of hydrocarbons, by liquid chromatography. It is.

The object of the invention is to provide a method for purifying and/or improving hydrocarbons using a new chromatographic method and a device for controlling and/or optimizing said method.

Another object of the invention is to solve the problem of quantifying aromatic hydrocarbons in hydrocarbon oils.

It is another object of the present invention to quantify not only aromatic hydrocarbons but also saturated hydrocarbons and polar compounds in hydrocarbon oils, and further to use this information as well as qualitative levels of aromatic hydrocarbons to quantify hydrocarbon oils. The purpose of this study is to determine the degree of saturated substitution of aromatic and polar components.

In one aspect, the present invention provides a method for the chromatographic analysis of hydrocarbon oils, comprising: (al) passing a mixture of hydrocarbon oil and a carrier phase in contact with a chromatographic stationary phase for a first time interval; retaining components of the hydrogen oil on said stationary phase; Cb) after step (a), applying a mobile phase to elute the various retained components of said oil from said stationary phase at different time intervals; passing the mobile phase in contact with the stationary phase for a second time interval and recovering the mobile phase in contact with the stationary phase together with components eluted from the stationary phase;
irradiating the recovered components in the recovered mobile phase with UV light having a wavelength range within about 400 nm for a period of time sufficient to expose the recovered components in the recovered mobile phase to the UV light within the wavelength range; (d) monitoring the absorbance of the UV light by the irradiated component across the wavelength range and obtaining an integral of absorbance as a function of photon energy across the wavelength range; and (e) measuring the magnitude of said obtained integral for at least one selected time corresponding to elution of one or more components.

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

In a preferred method of carrying out the invention, the mobile phase recovered from the stationary phase is irradiated with UV light having a wavelength range within the range of 230-400 nm.

A scaling factor of 2 is applied to the derivation of the integral of absorbance, doubling the magnitude of said obtained integral of absorbance, such that the scale factor is equal to the mobile phase recovered from the stationary phase in step (e). measured for a period of time corresponding to the polar component in the

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

The present invention also relates to such calibration as determining aromatic hydrocarbons of various ring numbers present in hydrocarbon oils. Calibration tests samples of hydrocarbon oils with known aromatic rings present such that the different times at which different aromatic hydrocarbons elute from the stationary phase relate to the ring numbers of these different aromatic hydrocarbons. This is essentially accomplished by doing so. This method is described in detail below.

In accordance with another aspect of the invention, there is provided a method for refining or improving the quality of petroleum hydrocarbon feeds, comprising analyzing each sample of the hydrocarbon oil produced during the process chromatographically by said method to obtain at least one of the components in the oil. 1. A method is provided for determining the presence level of a component and controlling operation of a process by the measured presence level of the at least one component.

Usually, but not necessarily, the control of operation of the process is to oppose an increase in the value of the presence level of said at least one component above a predetermined value.

One preferred method of carrying out the invention is a method of chromatographic analysis of hydrocarbon oils which may or may not contain asphaltenes, comprising: +8) a sample of oil and 1.6 to 8.8 cal" cm. −
(b) forming a mixture with a weak solvent having a solubility parameter within the range of ``(i) substantially all of at least the functionalized group; -NH;
, -CN, -No□, charge transfer adsorbents, charge transfer adsorbents functionalized with trinitroanilinopropane or tetranitrofluorene, homologues of any of the foregoing, and two or more of the foregoing. a solid chromatographic stationary phase having surface hydroxy groups substantially fully functionalized with functionalized groups selected from a combination of; (11) cyclohexane and isopropanol 0.0
Coronene capacity coefficient (cap) not exceeding 5.0 (preferably 2.5 or less) in a mobile phase containing 3% by volume
and (iii) a solid chromatographic phase comprising a combination of the features of (i) and (ii); 7 in contact with the solid chromatographic stationary phase;
, 6-8.8 cal! (d )
(e) monitoring the weak solvent recovered in step c1 for a second time period including a time interval after the first time period to detect eluent containing aromatic hydrocarbons; c) monitoring the weak solvent recovered in step (dl) and detecting an eluent containing saturated hydrocarbons simultaneously with and after step (dl); (g) passing a strong solvent having a solubility parameter in the range of 9 to 1000 for a third time period that is at least after the second time period and recovering the strong solvent that has contacted the stationary phase; monitoring the strong solvent recovered in f) to detect eluents containing heteroaromatic compounds, polar compounds and asphaltene materials; (1) recovering the strong solvent that has been in contact with the stationary phase through a strong solvent modified with a hydrogen-bonding solvent (e.g., an alcohol) that is miscible with the holding solvent for a fourth time period; monitoring the recovered strength solvent recovered in step h) to detect an eluent comprising a moiety selected from at least one of the group consisting of polar compounds and asphaltene materials.

Preferably, the change from weak to strong solvent is carried out over a period of time, ie there is a gradual change in solvent rather than a step change. It is observed that excellent separations are achieved with this method.

Regarding step (h), the strongly polar solvent and/or hydrogen bonding solvent preferably has the following properties: (i) it dissolves polar compounds and asphaltenes of the type found or expected in the sample; Must be able to do it. As a rule of thumb, a polar solvent or solvent combination between toluene and carbon disulfide satisfies this requirement, with dichloromethane being a convenient and preferred solvent that meets this criterion.

(ii) it must be able to displace the most polar heavy oil molecules from the solid adsorbent material, the addition to the solvent of one or more alcohols miscible with it imparts this property and the solvent is based on dichloromethane; A convenient and preferred alcohol is isopropanol at a volume concentration within the range of 1 to 50%, such as at or near 10% by volume. (iii) When ultraviolet spectroscopy is used for mass detection, the solvent (or solvent combination) must be transparent to UV light within the wavelength range used, as described herein. (iv) If a mass detection step is used that requires removal of the solvent (e.g. gravimetric analysis, flame ionization, among others), the solvent may be relatively volatile to facilitate separation of the solvent-free eluent. and the solvent must not associate too strongly with the polar molecules in the eluent.

Preferably after step (1) step (J) is carried out by passing a weak solvent in contact with the stationary phase in said one direction for a fifth time period which is at least after the fourth time period; Said weak solvent is preferably the same as or completely miscible with the weak solvent of step (c). Preferably after step 01 steps (a) to ('') are repeated as described in step (a) with another oil sample.

Monitoring of the eluent during step (81, (gl and TI) is carried out by UV absorption using UV at selected wavelength(s) and used during steps (a), (c), (f) and fhl. The solvent is preferably transparent to UV at a selected wavelength (M).A very significant advantage of using UV absorption to monitor the eluent is that it can be used for accurate determination of the mass of aromatic carbons as described below. It is possible.

Aromatic compounds of different ring numbers and substitutions exhibit different ultraviolet absorbance spectra. Therefore, a single wavelength cannot be chosen for all those measurements.

Each aromatic type has a different specific absorbance per unit mole (
(extinction coefficient) at a given wavelength and cannot be attributed to a constant response factor related to the absorbance for the mass eluting from the column in a complex mixture. A preferred method of implementing the invention has been devised to overcome this limitation. The new method uses the entire UV absorbance spectrum in the region 200-400 nm. A spectrum can be quickly acquired on the oil component eluting from the chromatography column with a diode array detector. Examples of these detectors in oil analysis have been published [e.g. in Jost].

HoJost) et al.
Kohle-Erdgas-Petroche IIie
) 3--E (4): 178 (19
84)) However, there is no report on the periodic measurement of aromatic carbon from UV spectra. In accordance with the present invention, it has been found that a mathematically derived quantity called the integrated oscillator strength (Q) calculated from the total absorbance spectrum is directly proportional to the level of aromatic carbon. fiQ is defined as: where A = absorbance, ε - photon energy, and the integral is taken over the range 200-400 nm.

To derive the mass of aromatic carbon eluting from the column during any time period that defines the oil content, the quantity Q is simply integrated over that time period and then multiplied by an appropriate constant reflecting the optical path length, integration time, etc. It will be done.

Next, one method by which Q can be determined in the case of a diode array detector will be described. Each detector produces an output signal proportional to the intensity I of the light it detects. A computer converts each detector output into a quantity A(λ) - i.e. absorbance, where λ
is converted to -, which represents the wavelength, and A=-1og. (-) and ■.

■. is the intensity of the UV source. The bandwidth Δλ received by each individual detector in the detector array is the same (e.g. 2
nm), but the wavelength varies (by increments or decrements equal to the bandwidth) from each detector to the next. The computer therefore multiplies IA(λ) by a weighting factor and sums it across the UV spectrum to derive an integrated oscillator strength Q.

The validity and accuracy of this method was verified by comparison with model components injected at known weights 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 approximately 2.0 (
or multiplying by a factor of approximately 2.0 before measuring the integrated oscillator strength) induce aromatic carbon. The accuracy of the integral oscillator strength method or technique is also determined by the fact that the horizontal axis gives the 1''3C-NMR result in units of weight percent aromatic carbon and the vertical axis gives the expected value in the same units, and the expected value is A(ε ) was shown for all oils by comparison with measurements of aromatic carbon by nuclear magnetic resonance (NMR) in various oil samples, as shown in Figure 1 derived from the integral of dε. A straight line graph showing the linear correlation between and integral oscillator strength values indicates parity. The data are shown for oils with very different degrees of saturation substitution, e.g. vacuum gas oil and coker gas oil, and for oils with very different polar content, e.g. hydrotreated gas oil and The parity line also fits for vacuum resid. The theoretical basis for this quantity independence for aromatic type is not completely understood.

The total mass of components eluting from the column can be determined, for example, by differential refractive index measurements, 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 measurements have the disadvantage that the refractive index of the components varies with their aromaticity and the extent to which the saturated carbons are paraffins or naphthenes. These drawbacks make it necessary to relate the measured refractive index to the mass of component elution using a charge type dependent response factor. Accordingly, the preferred method of carrying out the invention preferably uses solvent evaporation followed by flame ionization or light scattering to determine the total mass of the oil component, regardless of charge composition or charge type. In the case of flame ionization, the specific equipment used [1983 Pittsburgh Conference on Analytical Chemistry]
ence onAnalytical Chemist
Dixon (J, B. of Tracore Instruments) in the article 43 in RY).

It was found that the flame ionization apparatus described by Dixon) produced some volatilization of low boiling range oils as well as solvent evaporation and therefore it was most useful with vacuum distillation bottoms. In the case of light scattering, it is recognized that the light scattering response is a complex function of the mass of the eluted solute, and a suitable calibration function must be derived.

Recent publications [Mourey et al. (T, H9Mourey
and L, E, Oppenheimer), Analytical Chemistry (Analytical Ch.
emistry), 56:2427-2434
(1984)) dealt with the use of photodisruption detectors for polymeric HPLC. The inventors of the present invention have shown that this detector can be used for oil systems to measure the mass of all components regardless of the type of raw material charged. The calibration function is: mass - response (response) It is 1.

K1 and N2 are constants.

The combination of using one device to measure aromatic carbon mass and the other to measure total mass allows saturated carbon substitution to be determined by difference (or ratio). This appears to be a completely new concept in HPLC. Its validity was confirmed by comparison with HPLC and mass spectrometry and by showing that the aromaticity of the individual aromatic and polar components increases as expected during heat treatment.

According to a preferred application, the present invention analyzes at least one sample of a hydrocarbon mixture by the method described herein, whereby the following: saturated, aromatic, polyaromatic, polar compounds, asphaltenes and the aforementioned A method for evaluating the quality of a hydrocarbon mixture comprising determining the proportion of a species selected from at least one of a mixture comprising at least two is provided.

The hydrocarbon mixture can be a feedstock to a refining process or an intermediate treated oil between two refining stages.

Evaluations made with this preferred method of the invention indicate that the purification step or steps may be adjusted as necessary (within their acceptable operating limits) to meet optimal specifications for the product and/or intermediate products. or enable the production of products and/or intermediates with closely similar compositions.

The invention also provides in one application that the feed is passed through a fractionator having a temperature and pressure gradient to separate it into components according to their boiling range, said components being recovered from respective regions of the fractionator, and a light oil recovery region of the device. A method for refining or improving a petroleum hydrocarbon feed containing asphaltene material with a gas oil component boiling in the gas oil boiling range recovered from a gas oil fraction, the method comprising: taking discrete samples of the gas oil fraction from time to time from the recovered gas oil fraction; The method described in ＼ generates a signal indicating the amount of asphaltene substances present in each sample, and the operation of the separation equipment is controlled so that the amount of polar components in the light oil component is maintained below the planned amount. Provide methods for use in adjustment.

In other applications, the present invention further refines petroleum hydrocarbon feeds (e.g. boiling in the gas oil boiling range) where the feed is passed through a catalytic cracker and converted to cracked products comprising improved hydrocarbon materials. or quality improvement method, in which discontinuous samples of the feed proceeding to the catalytic cracker are taken from time to time and analyzed by the methods described in each case, and the polar components and the aromatic components having at least three rings (
generate a signal indicating the amount of 3+ ring aromatic hydrocarbons,
If and/or when the signal corresponds to an amount of 3+ ring aromatic and polar components exceeding the predetermined amount, the feed is mixed with a high quality feed, or subjected to catalytic hydrogenation, or mixed and A method is provided in which both hydrotreating is carried out and the amount of mixing and/or the intensity of the catalytic hydrotreating is increased and decreased in accordance with the respective increase and decrease in the magnitude of the signal.

In still other applications, the present invention also provides asphaltene materials, aromatic components comprising at least three conjugated aromatic rings ("3+
Aromatic hydrocarbons), a polar component, and a mixture of at least two of said contaminant components. and from the resulting mixture, (1) a hydrocarbon raffinate stream having a low content of polar and aromatic components; and (ii) a low content of solvent and said contaminant components. taking discrete samples of the raffinate stream from time to time, each analyzed by the method described herein to derive a signal indicative of the amount of contaminant components, and directly or indirectly used to vary the purification conditions such that the amount of contaminants in the raffinate is maintained under a selected plate.

DETAILED DESCRIPTION OF THE INVENTION In the individual descriptions, only features that are directly relevant to the disclosed embodiments of the invention are set forth, and features that are well known to those skilled in the art are not mentioned.

Figure 1 shows 6 new gas oil (VGO), 1 heavy coker gas oil (
Obtained by NMR measurements and integral oscillator strength ■ on samples of HKGO), 3 deasphalted oil (DAO), 5 heavy Arabian vacuum resid (HAVR) fractions, and 4 vacuum resid;
The predicted aromaticity was obtained from the 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 provides quantitative measurements of aromatic hydrocarbons that are independent of the type of feedstock. Therefore,
Requirements for response factors are eliminated.

Referring now to FIG. 2, the apparatus IO includes a chromatographic column 11 having an internal diameter of 4.6 mm and a total length of 25 cm. Column 11 consists essentially entirely of NH-functionalized silica in finely divided form with an average particle size in the range suitable for high performance liquid chromatography (HPLC), e.g. 5-10 μm, by the well-known slurry process. Packed with commercially available stationary phase.

Conduit 12 extends from the upstream end of the column to sample injection valve 13;
The sample is injected into valve 13 and conduit 12 through sample injection line 14 .

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

At the downstream end of column 11, conduit 21 transports 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 or) to a separation device (not shown). The mass-sensitive or mass-responsive detector 23 may be a refractive index, flame ionization or light scattering (
The detector may be a detector that monitors (after evaporation of solvent from the sample) or generates a signal in response thereto.

During the analysis, the microprocessor controller controls the two pumps19.
The operation of 20 is adjusted to maintain a substantially constant flow rate through column 11 of 0.5-2.0 ml/min. Initially, a weak solvent is used, which is substantially transparent to UV light and has solubility parameters sufficient to dissolve all components of the sample introduced into the column, but whose solubility parameters are is not so high that it is not possible to discriminate relatively sensitively between different chemotypes of . The solubility parameter, delta, is the square root of the quotient of the energy of evaporation divided by the molecular volume.
), Kirk and Osmer
Encyclopedia of
Chemical Technology (Encyclopedia)
of Chemical Technology), 2
Edition, Supplement, pp. 889-91o], that is, delta = (Ev/Vm) 1.5. The solubility parameter of the weak solvent should be within the range of 7.6 to 8.8 cal10·Sc'I·5, with a preferred weak solvent dissolving all the hydrocarbon components of the hydrocarbon oil sample without producing 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 above. Preferably, the solvent used is In order to maintain the adsorption properties at a constant value by deactivation of the residual silanol groups on the stationary phase, it is cyclohexane containing a proportion of polar solvent.Preferred polar solvents for this purpose are alcohols, especially 2-propanol. A mixture of cyclohexane, preferably 99.99 volumes and 0.01 volumes of 2-propanol, is pumped into column 11 by pump 19 during the first period of operation.
sent to.

A sample of the hydrocarbons to be analyzed during the first time period of operation is sent at a reference time via line 14 into injection valve 13 where it mixes with the weak solvent from pump 19 and removes precipitated materials such as asphaltenes. , to form a substantially homogeneous solution free of .

Sample size is not critical within the limits normal for high performance liquid chromatography; 0.4 mg sample is usually adequate. The resulting solution passes into the upstream end of column 11.

In another embodiment, a sample containing a solution of a hydrocarbon in which the solvent is a weak solvent (conveniently, but not necessarily, the same solvent as supplied to pump 19) is introduced through injection valve 13 as a "slug J". and it is pump 1
9 is propelled through the column by another weak solvent.

The liquid exiting the downstream end of column 11 is constantly monitored in UV detector 22 and mass sensitive detector 23. U
The V monitor detector 22 and the mass sensitive detector 23 are
It operates according to the principle described here. The responses 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 than aromatic hydrocarbons by the fixed packing material in column 11, the response in a mass-sensitive detector typically begins before UV absorption is detected, and the diffusive When an aromatic molecule passes through a mass sensitive detector, at the same time some aromatic hydrocarbon molecules pass through a UV detector, they tend to overlap during the UV absorption period.

The rate of diffusion or elution of molecules containing aromatic rings, as indicated by their speed through column 11, depends primarily on the number of aromatic rings in the molecule. Molecules with a single aromatic ring elute relatively quickly, and molecules containing two or more aromatic rings elute more slowly. Therefore, by calibrating column 11 with molecules containing different numbers of aromatic rings, it is possible to identify eluted molecules by the time taken to pass through column 11. Calibration can be done using appropriate methods such as toluene (
(1 aromatic ring), anthracene (3 fused aromatic rings) and coronene (6 fused aromatic rings). Calibration can be performed with additional and/or different polycyclic compounds.

During operation of the method described here, virtually all monoaromatic molecules elute within a time span comparable to toluene, and three-ring molecules elute in a time span comparable to anthracene after a time span of monoaromatic molecules. The six aromatic ring compounds elute during a time span comparable to that of coronene after that of anthracene. Molecules with a number of aromatic rings between toluene and anthracene and between anthracene and coronene elute after a time interval between each pair of molecules used for calibration.

When virtually all saturated and aromatic hydrocarbon molecules were eluted from column 11 by the weak solvent, as evidenced by the UV absorption and refractive index decreasing to their base values due to the solvent alone, the strong solvent (i.e. A solvent of relatively high polarity) is passed through the column at a progressively increasing rate by pump 20, while a weak solvent is passed by pump 19 at a correspondingly progressively decreasing rate such that the total volumetric rate of solvent remains essentially unchanged. Sent at speed. After the third selected time interval, no weak solvent is present and the only solvent that passes to the upstream end of column 11 is the strong solvent.

The strong solvent has a solubility parameter in the range of 8.9-10.0 cal°"cIll-"' and is transparent to UV.

A suitable strong solvent should be transparent to UV light at as low a wavelength as possible to facilitate calculation of the oscillator strength. The strong solvent should have a polarity between toluene and carbon disulfide, suitably dichloromethane. Dichloromethane can contain alcohol to enhance its ability to elute polar high molecular weight molecules. Suitably the alcohol is 2-propatol and the strong solvent may consist of 90% by volume dichloromethane and 10% by volume 2-propatol. In a variant of the apparatus of FIG. 2 described so far, pumps 19 and 20 can be used to pump weak and strong solvents (e.g. cyclohexane and dichloromethane) into mixing chamber 16 via tubes 17 and 18, respectively. Additional tubes 18a may be present to direct alcohol or other highly polar eluting substances from respective third pumps (not shown) to the mixing chamber 16. The third pump is preferably microprocessor-controlled in conjunction with pumps 19 and 20 according to a predetermined sequence or program in a manner known in the art.

If the alcohol or other highly polar solvent denaturant was not introduced during the third time period with the strong solvent, it is introduced over the fourth time period (eg, at or near 5 minutes). In each case, the 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 through column 11 for a fifth time period to elute highly polar molecules from the column. Elution of polar molecules is detected by a rain detector.

The polar molecules of a typical hydrocarbon sample, including asphaltenes, vary from 3 to 1 when only the strong solvent is sent through the column.
Virtually complete elution is achieved within a fifth time period of about 10 minutes due to the relatively fast decay of UV absorption after 0 minutes.

When the elution of the polar molecules was substantially complete, the strong solvent was gradually replaced by a weaker solvent (i.e., 99.99% by volume cyclohexane with 0.01% by volume 2-propanol) over a sixth time interval. Ru. Suitably, the sixth time interval may be within the range of 1 to 10 minutes.

The weak solvent can be replaced by first discontinuing the addition of the alcohol denaturant to the strong solvent and then by gradual displacement of the strong solvent by the weak solvent. The next hydrocarbon sample can then be passed through the column through injection valve 13 along with the weak solvent.

Referring now to FIG. 3, the upper graph 30 shows the response of a substance passing through the mass-sensitive evaporative light scattering detector 23 over time; the lower graph 31 shows the response of a substance passing through the UV detector 22. Figure 3 shows the change in UV transducer intensity over time.

Time on the horizontal axis is shown in 3 second intervals or increments (hereinafter sometimes referred to as "channels") from a reference time "0" which is 40 channels after sample injection.

The sample was 0.4 μ of heavy Arab vacuum residue. The solvent is simultaneously gradually changed in proportion by means of pumps 19.20;
Or send 1.0mj individually! A constant solvent flow rate through column 11 per minute was provided.

During the initial time before the reference time, only the weak solvent is passed through the pump 19 at the speed of 10 m17 min, and the light scattering signal and the U
The V oscillator strength remained at a constant level during this time. Only weak solvent was supplied by pump 19 through injection valve 13 for 7 minutes from the time of injection of the hydrocarbon oil sample. Immediately thereafter, the strong solvent was gradually replaced by the weak solvent at a uniform rate (ie, linearly over 2 minutes). Strong solvent alone was then supplied by pump 19 through injection valve 13 for 4.0 minutes, at which time it was gradually replaced by denatured strong solvent over a period of 0.1 minute, and the flow was maintained for the next 12.9 minutes. In each case, a time delay occurs from the time of passing through the injection valve 13 until, for example, the sample or the respective solvent reaches and passes through the column.

A 0.4 μ sample of vacuum residual oil was injected into the injection valve 13 from the sample injection line 14 into the 40th channel at the reference time. Due to time delay, the first 40 channels were
None of the vessels showed any deviation from the stable baseline prior to sample injection. The light scattering signal detected by detector 23 after 11 channels includes a sharp increase in response from baseline 32 to a maximum point (point 33), then a gradual decrease to the solvent-only value, and at intervals one or more showed changes punctuated by an increase in response. The light scattering signal was responsive to the elution of 40 μg of benzo(α)anthracene, which was included as an internal standard and indicated by peak 34. The elution of a polar heteroaromatic itinerary based on a solvent change to dichloromethane was indicated by peak 35, and the elution of a strongly polar heteroaromatic itinerary based on a change in solvent to 90% dichloromethane, 10% isopropanol was indicated by peak 36. .

Regarding the UV oscillator intensity graph 31, the increase in absorbance from the baseline starts at about channel 15 and increases at about channel 24.
It can be seen that a peak (point 37) was reached in the channel. The peak value of absorbance was maintained for a short time and then remained above the baseline indicating the aromatic hydrocarbons eluting at each particular time.

At point 38 the internal standard response appears.

In channel 219, which approximately 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 is due to the polar compound-based peak (point 3).
9) and then showed a relatively rapid decline. The small additional beak 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 addition of 10% by volume of isopropanol. Finally, the detector response is at point 42
It returned to a value very close to the initial baseline at which time data collection was stopped.

The relationship between the variations in light scattering response and UV oscillator intensity with solvent type is as follows: the initial change in light scattering corresponds to the elution of saturated hydrocarbons and a small proportion of aromatic hydrocarbons. The saturated hydrocarbons produce a peak at point 33, and the subsequent decline in light scattering indicates relatively complete elution of the saturated hydrocarbons and associated contribution from the eluting aromatic hydrocarbons. Point 3
The relatively steep rise in UV absorbance up to 7 is attributed to the elution of aromatic hydrocarbons in the weak solvent. An aromatic itinerary with an increasing number of rings subsequently elutes from the column with the weak solvent, as indicated in part by the internal standard. The sharp increase in UV absorption that begins a short time after the onset of the gradual transition from weak to strong solvent and reaches the highest point in the peak absorbance (point 39) after the composition of the mobile phase changes to strong solvent only indicates the elution of polar compounds. It is reduced to Polar compounds are eluted relatively quickly and efficiently (given their relatively high molecular weight and physicochemical properties) by strong solvents until they are substantially completely removed from the column.

The elution of the highly polar substances evidenced by peaks 40 and 41 results in complete recovery of the oil injected into the column.

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

The proportion of each hydrocarbon type or component in the sample transforms the light scattering response into a linear function of the total mass and the UV oscillator intensity into a function of the mass of aromatic carbon, as described here. obtained by integrating over the retention time interval. The components are defined by retention time intervals. Therefore, saturated hydrocarbons are compounds that elute within channels 9 to 16, monocyclic aromatic hydrocarbons are compounds that elute within channels 16 to 24, and two-ring aromatic hydrocarbons are compounds that elute within channels 16 to 24.
3-ring aromatic hydrocarbons are assumed to elute in channels 40-40, 4-ring aromatic hydrocarbons are assumed to be eluted in channels 75-200, and weakly polar components are eluted in channels 200-200. As those eluting in 300 channels, and strongly polar components are 300~
It can be defined, determined, or considered as eluting in 400 channels. The use of model compounds to define components is described herein (eg, with respect to Figures 1 and 2).

Column quality is determined by chromatographing a "cocktail" containing toluene, anthracene and coronene in cyclohexane.

The column is tested incrementally with cyclohexane and 0.01% 2-propanol. Capacity coefficients are 0 for toluene, anthracene and coronene, respectively.
．． 1.0.5 and 2.0, and the capacity coefficient is column 1
It is the amount of retention volume minus void volume divided by the void volume of the stationary packed phase in 1. 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 too much, the capacity factor will increase. It is also recognized that columns from different manufacturers exhibit widely different capacity coefficients and separation performance, even if they are all nominally NH, bonded silica.

A summary of capacity factor data for adsorbents of different sources is given in Table 2. Columns with capacity coefficients for coronene greater than 5 gave poor separation due to low yields of aromatic and polar components.

Classifications performed using the cyclic semi-adjusted scale of this operation show good selectivity for microconradson carbon residue (MCR), a measure of coke formation tendency, and excellent selectivity for metalloporphyrins.

In practical tests of the disclosed method, cold lake bitumen has an MCR of 65% non-polar compounds (saturated and aromatic hydrocarbons) and 34% MCR showing an MCR of 2.7.
37% of the polar compounds were separated. The total bitumen had an MCR of 14.3% by weight. The heavy Arabian vacuum resid was separated into a non-polar fraction with a MCR of 9, 53-58%, and a polar fraction with a yield of 43-47% and an MCR of 45-47%. Total residual oil is 23% by weight MC
It had R. There were no metalloporphyrins detectable by visible spectroscopy in the non-polar fraction (≦lppm)
. These data demonstrate that difficult-to-process components (i.e. substances that may be detrimental to the quality of the hydrocarbon sample and/or adversely affect its subsequent use) are concentrated in polar fractions, as well as non-polar and polar fractions. It is shown that selective separation of compounds with high yields was achieved. The operation preserves aromatic hydrocarbons as a function of their degree of conjugation. In all analyzes using the method and apparatus of the present invention, saturated, aromatic,
Ninety-nine percent of the polar molecules and asphaltene fractions are recovered within a relatively short analysis cycle (eg, 30 minutes). This is due to open columns, e.g. sample recovery is incomplete, typically around 95%, and analysis requires relatively large samples (e.g. on the order of 3 g) and relatively long sampling times (e.g. on the order of 8 hours). Contrasted with that used to perform the ASTM D-4003 conventional method.

The reproducibility of the stationary phase was demonstrated in detail in practical tests. Each individual column 11 was used for well over 100 analytical cycles at a 4 mg load before any significant loss in performance was observed. The described chromatographic method and apparatus can be easily adapted for automated operation. The complete analysis train described as a non-limiting example in connection with FIGS. 2 and 3 takes 30 minutes, but it can obviously take a different amount of time, and within the total time of each cycle:
The operation of the pumps for weak and strong solvents, the timing of oil sample injections and the recording of UV absorption data (and mass detector data if necessary) can all be controlled by automatic sequencing equipment. Since such automatic sequencing equipment is well known and readily available from commercial manufacturers, and furthermore, since it does not form a direct part of the present invention and is merely a common item of equipment, a description thereof is omitted here. Not provided.

The chromatographic method and apparatus described are useful for controlling or optimizing processes for the evaluation of hydrocarbon mixtures or for purifying or improving hydrocarbon feeds, e.g. for the fractional distillation of hydrocarbon-feeds, in which at least a portion of the feed is It can be used in the preparation of feeds for catalytic cracking which are catalytically hydrogenated to reduce their recalcitrant properties, and in particular in the solvent purification (eg deasphalting) of hydrocarbon mixtures.

Comparative Example Journal of Chromatography (1981) 2
06.Bolet (c, Bo
) and high performance liquid chromatography (HPLC), which is said to be able to analyze vacuum residues (boiling range above 535°C) for saturated, aromatic, and polar compounds.
The technology is described. The technique uses two imitations. 1st
In the simulation, the saturated hydrocarbon has a length of 20 cm x an inner diameter of 4.
Aromatic hydrocarbons and polar compounds are separated using a 10 μm silica-bonded alkylamine stationary phase in an 8 mm column. The mobile phase used was n-hexane and it is stated that for asphaltene-containing samples cyclohexane should be used as the mobile phase to avoid precipitation of asphaltenes. Although the paper does not state that there is complete recovery of the sample in the eluent,
However, the paper could be interpreted to mean that there is actually 100% sample recovery.

A Merck Lichrosorb -N H2-functionalized silica-packed chromatograph was used according to the second procedure of Bollet' et al., in which the separation of saturated hydrocarbons as well as aromatic compounds from polar compounds was carried out using more polar solvents. The graph column was treated 2. with a solvent consisting of 85% cyclohexane and 15% chloroform. On
Equilibrated at a flow rate of 1/min. 120 μg of Arabian heavy vacuum distillation residue (950+'F, 510+°C) is dissolved in 20 μg of cyclohexane! was injected into the column inside. Detection was by monitoring UV absorbance at 254.280 and 330 nm. The resulting chromatogram (at 280 nn+) is shown in Figure 4a and shows the dilution of saturated and aromatic hydrocarbons. The flow was then reversed (backflush). Polar compounds eluted over the next 10 minutes, by which time a stable baseline was reached. This is shown in Figure 4b (UV absorbance was monitored at 280 nm). The sharp peaks reported by Boret were not observed.

This concludes Boret's analysis.

Bolet et al.'s method leaves a significant amount of sample material, mainly polar compounds, in the column, as seen in the following results. , while 100% recovery (or substantially 1
00% recovery) is achieved by this method.

To demonstrate that recovery of polar compounds was incomplete, and as an example of one way of carrying out the process of the invention, the flow was reversed to its normal (advancing) direction to 90% dichloromethane and 10% isopropanol. of solvent was introduced in a solvent gradient over 10 minutes. The absorbance was measured for 20 minutes, during which time an additional peak due to strongly retained polar compounds appeared at about 8 minutes (Figure 4, showing absorbance at 280 nm).

Therefore, Boret's method leaves some polar material on the column. The absorbance in each of Figures 4a-40 was integrated over time to obtain a measure of how much material was removed from the column at each step. The results are as follows: Normalized area (%) 1 Upstream cyclohexane: Chloroform (85:15) 79.5 - Eluent: Saturated and aromatic hydrocarbons - Backflush cyclohexane: Chloroform (85:15) 8. 4- Eluent: Polar Compound One Flow Dichloromethane: Isopropanol (90:10) 12.1- Eluent: Additional Polar Compound Bolet The amount of material that the method leaves on the column is approximately 12% of the vacuum residue sample %. This creates some problems that are avoided or overcome by the method disclosed herein, namely that the material left on the knee column is not properly evaluated in the compositional analysis.

- Materials left on the column create adsorption sites for subsequent analysis, giving irreproducible results.

- Materials left on the column can effectively block flow, resulting in high backpressure and loss of operation.

In order to achieve good recovery of residual oil from HPLC columns, solid adsorbent materials must be functionalized to mask inorganic oxides and hydroxyls.

The final elution solvent exhibits solubility for asphaltenes,
It must have hydrogen bonding functionality and/or highly polar functionality to neutralize the surface activity of the adsorbent.

A preferred combination is to use primary amine-functionalized silica as the adsorbent and a blend of dichloromethane and isopropanol, where the isopropanol is the final solvent in the oil elution at 1-50%. It is present in a volume concentration within a range, most preferably 10%. This solvent can be introduced in a cocurrent or backflush manner.

What is important is the solubility and polarity of the solvent, not the direction of flow.

In a separation variant, a three-pump system is used.

A first pump supplies cyclohexane, a second pump supplies dichloromethane, and a third pump supplies isopropanol.

The feed rate will be changed in due course. Cyclohexane is used to elute saturated hydrocarbons followed by aromatic hydrocarbons,
The weakly polar compounds are then eluted with dichloromethane and finally the strongly polar molecules are eluted with dichloromethane 7910% isopropanol. Accurate solvent composition programs are not critical to obtaining information as component assignments can vary. It is important to increase the solubility parameter of the solvent as the chromatography progresses so that oil components of successively 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 invention as indicated by the claims.

The ability to accurately analyze residual oils is one of the more important advantages offered by the disclosed method over the prior art. However, Boleft has some other advantages of the present method compared to the prior art, namely, instead of a two-knee maneuver, only a one-step maneuver is used, which simplifies the method.

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

- The described detection sequence allows the quantification of oil components without the need to obtain response factors for each compound type.

In each of the aforementioned purification or quality improvement methods (i.e. distillation, solvent purification and catalytic cracking or coking), the chromatographic method and apparatus can be used to detect unacceptable levels of individual types of hydrocarbons or other substances. , based on such detection, signals may be induced or generated. Therefore, with reference to each of the aforementioned methods in turn, the following are the main objects and methods achieved by the present invention: (1) Hydrocarbon feed containing distilled asphaltene materials (hereinafter referred to as "asphaltenes" for H&) In the distillation of distillates, many factors can result in the entrainment or carryover of excess amounts of asphaltenes into the distillate fraction, especially the gas oil fraction. Such factors include excessive stripping distillation rates; excessively high heat input to the bottoms recycle stream; excessively high feed rates;
However, it is not limited to these.

Since the presence of excess asphaltenes in the distillate is usually detrimental to the quality of the distillate and/or its further use, the use of the disclosed apparatus and method for detecting excess asphaltenes is an optimal method for distillation column operation. It represents an important step towards becoming a leader.

According to this aspect, a 0.4 mg sample of gas oil from the distillation column is injected at a suitable standard temperature (e.g. 25° C.) into the apparatus of FIG. 2 through valve 13 and as described with respect to FIGS. Chromatographed.

Asphaltenes are highly polar and their concentration in gas oil samples can be easily determined from the area under the UV oscillator intensity curve (e.g. between points 38 and 42 in Figure 3) during elution with strong solvents. I can do it. The area under the UV oscillator intensity is
determined by well-known and conventional methods for doing so;
One or more known means of reducing asphaltene entrainment in the distillation column when the area exceeds the allowable area can be implemented. Since it is usually undesirable to reduce the feed rate to the column,
The first measure that can be used is to reduce the speed of the stripping steam. The reduction in heat input to the column can be compensated for by increasing the bottom reflux temperature rather than the feed temperature to adjust asphaltene carryover, as known to those skilled in the art. Adjustment of the operation of the distillation column with asphaltenes determined by the disclosed chromatographic method can be carried out by manual adjustment, by the operator on the basis of the chromatographic output, or automatically and also on the basis of the chromatographic output. can.

(2) Solvent Purification In solvent purification, the feedstock is brought into intimate contact with a solvent that has selective solubility or affinity for the particular type of material in the feed, and the resulting solution is separated from the residual raffinate. In solvent deasphalting, a feed containing asphaltene materials (hereinafter referred to as asphaltenes for brevity) is completely miscible with non-asphaltenes, but with short chain n-paraffins, such as n-propane, which are immiscible with asphaltenes. The asphaltenes form a second heavy phase which can be removed by suitable separation methods such as decantation.

If the deasphalting operation is carried out at an excessively high rate for the separation of asphaltenes from the resulting solvent-oil solution in the active equipment, asphaltenes will be entrained into the deasphalting solution.

To monitor the asphaltene content of the deasphalting solution, a sample of the deasphalting solution is passed at a suitable standard temperature through a chromatographic apparatus of the type described with respect to FIG. Area below (point 3 in Figure 3)
8-40 (corresponding to the area under curve 31) is determined by any known technique. If the area exceeds the area representing an acceptable amount of entrained asphaltenes, the feed rate is reduced, either by manual intervention or automatically, until an acceptable asphaltene entrainment level is reached.

(3) Preparation of catalytic cracking feeds [and/or quality improvement of gas oils] Catalytic cracking feedstocks in particular, and gas oils in general, have molecules containing varying proportions of one or more aromatic rings and/or polar Contains molecules. Polyaromatic molecules tend to resist cracking during their passage through the catalytic cracker and thus tend to be concentrated in the cracked products, while polar molecules break down during cracking to produce relatively large carbonaceous materials. providing the precipitate on the catalyst;
This tends to impair the catalytic activity of the latter. Furthermore, gas oils and other fractions containing polycyclic aromatic structures tend to produce smoke when combusted, and due to at least said considerations polyaromatic molecules and polarity in gas oils and other hydrocarbon fractions It is desirable to be able to control the levels of molecules.

One way in which the enrichment of asphaltenes, resins and polyaromatic ring molecules in distillate fractions such as gas oils can be controlled is by controlling the cut point of the fraction during distillation; I have already mentioned this in connection. When the concentration of asphaltenes and polyaromatic rings in the distillate fraction from the distillation unit is observed to exceed the desired maximum concentration using the chromatographic equipment and method described, the concentration of asphaltenes and polyaromatic ring molecules Signals indicative of UV absorption properties and their excess concentration are induced and used to control distillation unit operation until the concentration of such molecules is reduced to an acceptable level in the distillate fraction.

In the context of catalytic cracking, one way to reduce the tendency of aromatic molecules (including polyaromatic molecules) to become concentrated in the cracked products is to ensure that the resulting naphthenic structures (i.e., cycloparaffinic structures) are decomposed relatively quickly. Therefore, it is necessary to hydrogenate them.

Hydrogenation also tends to reduce the concentration of polar compounds.

The hydrogenation is carried out using a suitable hydrogenation catalyst, such as a combination of metals of Groups 1 and 2 (e.g. Mo
and Co).

In relative terms, hydrogen is an expensive commodity and therefore
It is highly desirable to hydrogenate only a selected proportion of the hydrocarbon material for which hydrogenation results in the production of cracked products of acceptable quality from an economic standpoint. The proportion to be hydrogenated can be determined by directing the desired proportion to the hydrogenation apparatus, or by passing the entire feed through the hydrogenation apparatus and changing the hydrogenation conditions to achieve the desired proportion of hydrogenation, or by using both of the above means to an appropriate degree. It can be selected by combining them. Generally speaking, catalytic hydrogenation of polyaromatic molecules results in hydrogenation of only one aromatic ring in the molecule at a time per hydrogenation. The hydrogenated rings are cracked when passed through a catalytic cracker, and the resulting molecules with one less aromatic ring are further cracked until the content of recalcitrant aromatic molecules in the cracked product is reduced to an acceptable level. Hydrogenated to facilitate cracking of additional saturated aromatic rings in each subsequent pass through the catalytic cracker.

Catalytic hydrogenation of polar molecules is also carried out to the extent necessary to increase the quality of the hydrocarbon fraction to a level suitable for its further use, such as catalytic cracking.

By way of example, reference is now made to FIG. 5, which illustrates the main features of a catalytic hydrotreater 50 that embodies process control in a block chemical engineering flow diagram. In this non-limiting example, the device is for improving the quality of a catalytic cracker charge, but one skilled in the art will recognize that it can be used to improve the quality of a charge for other purposes.

The raw feed (e.g. gas oil from a vacuum distillation column) passes via line 51 to a sampling point 52 where the main stream passes via line 53 to a catalytic hydrogenation facility, hereinafter "for brevity"
Proceed to ``Hydrotreater'' 54. Alternatively, the product leaving hydrotreater 54 via line 59 and passing through line 60 to a catalytic cracker (not shown) can be sampled via line 57 and valve 56.

An automated high performance liquid chromatograph (HPLC) analysis and control device 61, particularly embodying an apparatus of the type described with respect to FIG. 2, analyzes a sample of the raw feed from line 55 or the treated feed from line 57; The operation of hydrotreater 50 is adjusted so that the feed in line 60 is of acceptable quality. The sample used was line 6
It is discharged after 2 steps.

The HPLC device 61 has at least the following regulating effects (among others): (a) the flow rate of the feed through the hydrotreater and hence the residence time or space velocity; (b) the hydrotreater 5 as determined by the hydrogen control device 63
The ratio of hydrogen to feed in 4. As already mentioned, hydrogen is relatively expensive and it is preferable to find an economic balance by comparing the cost of hydrogen use with the increased value of the hydrogenated feedstock. Hydrogen control device 63 plays a role in achieving this economic balance.

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

Feed rate, hydrogen control device 63 and temperature control device 6
Each of the four adjustments can be made manually or automatically, or by a combination of manual and automatic operations. When automatic control of one or more adjustments is used, control can be by a conventional type computer (not shown). A suitable program for the control computer to manage some or all of the operation of apparatus 50 can be devised by a qualified programmer. Neither the control computer nor its software will be described as they are both within the current state of the art and neither are directly germane to the invention as defined by the claims.

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

The coarse feed in line 51 is first passed through line 53 in at least a major portion to the hydrotreater and then in line 5.
9 to the catalytic cracker feed line 60.

The feed in line 55 and the product in line 57 are periodically (e.g. every 60 minutes) and optionally passed 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. IIPLC
Analysis by device 61 is performed generally and in the manner described specifically with respect to FIGS. 2 and 3.

From the analysis in device 61 a signal indicating the composition of the crude feed is induced into signal lines 67 and 68.

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

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

A common adjustment of temperature controller 64 is one suitable for aromatic nucleus saturation, ie, a relatively low hydrotreating temperature in the range of about 300-510°C. However, conventional regulation is regulated by signals from a control computer that reach temperature controller 64 via signal line 70 to adjust the heteroatom content (i.e., polar molecule content) of the crude feed to accommodate the saturation of aromatic rings in the crude feed. The hydrotreating temperature is increased to reduce the temperature to an acceptable level corresponding to the level that can be achieved.

The regulation of valve 56 can be varied by human intervention or by signals from the control computer (signal line 71) for the flow and frequency being analyzed.

Some additional illustrations of the disclosed methods are now provided in the following non-limiting examples.

Example 1 Preparation of a Lubricating Oil Base Stock In the production of a lubricating oil base stock, the objective is primarily to separate molecules from the feedstock that have good lubricity, including a high viscosity index. Saturated hydrocarbons and aromatics with no more than one ring are most preferred. The two important steps in the production of heavy lubricating oil feedstocks of the type known as brightstock are:
The two steps are deasphalting the vacuum resid with propane to produce a deasphalted oil and extracting fused ring aromatic hydrocarbons and resins from the deasphalted oil with a polar solvent such as phenol to produce a raffinate. The asphalt produced during the first stage and the aromatic-rich extract produced during the second stage are by-products and have other uses.

The HPLC techniques described are used to monitor the molecular composition of the stream and adjust process conditions to achieve the highest yield of raffinate within quality specifications based on molecular composition.

Samples of each process stream were obtained and analyzed according to the instructions in Figures 2 and 3. An evaporative light scattering detector was used.

It was linearized by equations (2) and (3) by measuring its peak response to known concentrations of vacuum gas oil. The integration level of each component whose retention time limit is defined by the model component is shown in Table 3 in terms of weight percent of the total sample.

Observation of the data suggests process changes, which will be apparent to those skilled in the art of lubricant base stock manufacturing.

The asphalt rejected from the deasphalting stage contains 15.7% saturated hydrocarbons. Some or all of these could be incorporated into the deasphalted oil by lowering the temperature in the deasphalter and increasing the processing ratio (ie, solvent to charge ratio). Deasphalted oil contains 3- and 4-ring aromatic hydrocarbons;
It is below the detection limit, but it is concentrated in the extract. Although the extraction step was effective in removing 2-, 3-, and 4-ring aromatic hydrocarbons from the raffinate, trace amounts 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 ratio. Process changes are likely to be made by balancing the cost of the change versus the benefit in improved product quality or quantity.

Saturation 30.015.7 60.5 19.1 75.
2 aromatic 1 19.4 14.6 2B, 8 3
4.5 22.6 Aromatic 2 7.8 7.7
5.8 L7.4 0.0 Aromatic 3 2.
9 5.7 0.0 10.1 0.0 Aromatic 4 2.2 4.9 0.0 8.1 0
．． 0 polarity 37.851.4 2.7 8.9 0.5
Example 2 Production of Catalytic Cracking Feedstock Heavy vacuum gas oil and heavy coker gas oil are produced by vacuum distillation and fluid coking methods, respectively. These streams are found to be too high in sulfur, nitrogen, 3+ ring aromatic hydrocarbons, and polar compounds for effective catalytic cracking. Therefore, they are mixed and subjected to a hydroprocessing process in which they are passed sequentially through two reactors. Both reactors are charged with commercially available 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 (373,9C). Residence time is approximately 22 minutes in each reactor.

The molecular composition of the feed is compared with the products of the first reactor and the second series reactor by the HPLC method of the present invention. Separation is carried out by the method described in connection with FIGS. 2 and 3. The detector is a UV diode array spectrophotometer.

The integral oscillator strength is calculated as in equation (1) above and converted to weight percent aromatic carbon by the correlation of FIG. The composition of the popular stream is given in Table 4. It is clear that the quality of the feedstock is improved across each reactor.

A fundamental quality improvement occurs in the content of 3+ ring aromatic hydrocarbons and polar compounds, which is only about 172 of the starting level. One- and two-ring aromatic hydrocarbons are produced by hydrogenation of polynuclear aromatic hydrocarbons.

Valid information in Table 4 can be used to adjust the process. 3
The product level of + ring aromatic hydrocarbons + polar compounds is
Below the adjustment point determined to provide a good catalytic cracking charge, the plant operator decides, for example, to either reduce the residence time through both reactors or bypass the second reactor altogether. be able to. Other common methods of control would be to vary hydrogen partial pressure or temperature or both.

Person-1 (l-ring aromatic nucleus 3.7 5.6 6
．． 72-ring aromatic nucleus 5.0 6.4
6.73 ring aromatic nucleus 5.5 6.0
4.74-ring aromatic nucleus 8.9 5,2
3.7 Polar nucleus 10.0 6.
25.0 The invention as claimed is not limited to the particular embodiments disclosed. Furthermore, features described in connection with one embodiment may be used in other embodiments without departing from the claimed invention. Additionally, the disclosed UV detection technique to induce integrated oscillator intensity can be used alone in HPLC to measure the level of aromatic carbon present, or in combination with amount-sensitive measurement techniques (both weak and strong eluents). can be used to measure the levels of saturated hydrocarbons, aromatic hydrocarbons, and polar compounds in oil samples (using solvents).

[Brief explanation of the drawing]

Among the drawings referred to by way of example in the description of the present invention, FIG.
2 is a regression analysis graph of the weight percent of aromatic carbon (on the horizontal axis) in various hydrocarbon oil samples by MR versus the expected weight percent of total aromatic carbon in the eluent derived from the integrated oscillator strength; The figure is a route map showing one form of equipment used in one method of carrying out the method of the invention; FIG. This is a graph showing time on the axis; Figure 4 is a graph showing time on the axis; Figure 5 shows a method in which the conditioning apparatus embodies an apparatus for use in accordance with one method of carrying out the method of the invention; This is a chemical engineering flow sheet for the adjustment device. There is no change in the contents of Figure 3) Comparison of the characteristics of the N-R intergalactic tribe Prediction of the accuracy of the Wanku nuclear detector 2 Te @
πSaara'i-+, o0 wo5 report fui+2o0
Collection game [Ihi, 4 pieces of nuclear FIG, 1. Chromatoplum of heavy arago decompression residue 'Tsukuda': f7 non-denitrifying system active FIG, 5. Patented on February 1998 Office Commissioner Yoshi 1) Moon Takeshi 1, Indication of case 1999 Patent Application No. 120235 3, Relationship with the case of the person making the amendment Applicant name Title Exxon Research and Engineering Company 4, Written amendment to attorney's procedure 1.9. 22 Month, Day 1, 1998, Indication of the case, 1999 Patent Application No. 120235, 4, Agent 7, Contents of amendment: Figure 1 of the drawing is corrected as shown in the attached sheet.

Claims (15)

[Claims] (1) A method for the chromatographic analysis of a hydrocarbon oil, comprising: (a) passing a mixture of a hydrocarbon oil and a carrier phase in contact with a chromatographic stationary phase for a first time interval; (b) after step (a), applying a mobile phase to a second time interval to elute the various retained components of the oil from the stationary phase at different time intervals; (c) collecting the collected mobile phase together with the components eluted from the stationary phase;
irradiating the recovered components in the recovered mobile phase with UV light having a wavelength range within the range of about 400 nm for a period of time sufficient to expose the recovered components in the recovered mobile phase to the UV light within the wavelength range; substantially transparent to light; (d) monitoring the absorbance of the UV light by the irradiated component across the wavelength range and obtaining an integral of absorbance as a function of photon energy across the wavelength range; and (e) measuring the magnitude of said obtained integral for at least one selected time corresponding to elution of one or more components. (2) The mobile phase recovered from the stationary phase is 230 to 400n
irradiated with UV light having a wavelength range in the range of m, a scaling factor of 2 is applied to the derivation of the integral of absorbance such that the magnitude of the obtained integral of absorbance is doubled, and said magnitude is reduced to a step ( 2. The method of claim 1, wherein in e) the polar components in the mobile phase recovered from the stationary phase are measured for a period of time. (3) Claim (1) wherein the absorbance of UV light by the irradiated component is monitored using a diode array detector.
Method described. (4) corresponding to steps (a) to (d), but with the corresponding ring number of each selected molecule at various times at which the selected molecule is observed to elute from the stationary phase in the step corresponding to (d); The stationary phase is calibrated by replacing the hydrocarbon oil with a selected molecule containing a known varying number of aromatic rings to relate to the number of aromatic hydrocarbon rings in the hydrocarbon oil. of the different aromatic hydrocarbons present in the hydrocarbon oil, determined by comparing the time response in step (d) with different times corresponding to different numbers of aromatic rings determined in the calibration. The method according to claim 1, wherein the ring number is determined. (5) The method according to claim (4), wherein toluene, anthracene and coronene molecules are used to calibrate the stationary phase for one-, three- and six-ring aromatic hydrocarbons. (6) the mobile phase is a weak solvent that elutes saturated and aromatic hydrocarbons (but not polar compounds) from the stationary phase, and after substantially all the saturated and aromatic hydrocarbons have eluted, the polar compounds Claim (1), wherein a strong solvent is substituted for the weak solvent to elute from the stationary phase.
Method described. (7) The stationary phase comprises an amine-functionalized silica stationary phase, and the weak solvent is 7.6-8.8 cal^0^. ^5cm^-^1^
．． It has a solubility parameter in the range of ^5 and the strong solvent is 8
．． 9-10.0cal^0^. ^5cm^-^1^. ^
Claim (6) having a solubility parameter within the range of 5.
Method described. (8) the mobile phase is a solvent, and the method further comprises (i) measurement of the refractive index of the eluate; (ii) solvent evaporation and subsequent flame ionization of the solvent-free eluate; and (iii)
The method of claim (1), comprising the step (f) of detecting the total mass of components eluted from the stationary phase by a method selected from solvent evaporation and subsequent monitoring of light scattering of the aerosol of the solvent-free eluate. . (9) The magnitude of the obtained integral is measured in step (e) for a time corresponding to the presence of aromatic hydrocarbons in the solvent and the measured level of aromatic hydrocarbons present and eluted from the stationary phase. 9. A method according to claim 8, comprising the step of obtaining a difference or ratio between the detected total mass of hydrocarbon components. (10) The method according to claim (6), wherein after some polar compounds have been eluted by the solvent, the solvent is modified with a hydrogen-bonding solvent that is miscible with the strong solvent in order to elute more polar components of the oil. . (11) A method for refining or improving the quality of a petroleum hydrocarbon feed, wherein each sample of hydrocarbon oil produced during the process is chromatographically analyzed by the method set forth in claim (1) to determine the amount of water present in the oil. A method for determining the presence level of at least one component and controlling operation of a process by the measured presence level of the at least one component. (12) The method of claim 11, wherein controlling the operation of the process is to oppose an increase in the value of the presence level of at least one component above a predetermined value. (13) The feed is passed through a fractionator having a temperature and pressure gradient to separate the components according to their boiling range, said components being recovered from respective regions of the fractionator and from the gas oil recovery region of the device. 1. A method for refining or improving an asphaltene-containing petroleum hydrocarbon feed comprising a gas oil component boiling in the gas oil boiling range, wherein discrete samples of the gas oil fraction are taken from time to time from the recovered gas oil fraction, each comprising the steps of claim (1). Analyzed by the method described, generates a signal indicating the amount of asphaltene material present in each sample, which is used to adjust the operation of the fractionation equipment so that the amount of polar components in the light oil component is maintained below the predetermined amount. how to. (14) A method for refining or upgrading a petroleum hydrocarbon feed in which the feed is passed through a catalytic cracker to be converted to a cracked product comprising improved hydrocarbon material, the feed being Taking discontinuous samples from time to time and analyzing each by the method described in claim (1),
A polar component and an aromatic component having at least 3 rings (“3
generating a signal indicative of the amount of 3+ ring aromatic hydrocarbons (3+ ring aromatic hydrocarbons) and discharging the feed if and/or when said signal corresponds to an amount of 3+ ring aromatic components and polar components that exceeds the predetermined amount; Mixed with a high quality feed, or subjected to catalytic hydrotreating, or both mixed and hydrotreated, the intensity of the catalytic hydrotreating increases and decreases in accordance with the respective increases and decreases in the magnitude of the signal. How to be reduced. (15) Undesirable contaminant components selected from asphaltene substances, aromatic components containing at least three conjugated aromatic rings (“3+ ring aromatic hydrocarbons”) polar components, and mixtures containing at least two of the aforementioned contaminant components. A method for refining and improving a petroleum hydrocarbon feed comprising: mixing streams of a selective refining agent at selective refining conditions; and removing from the resulting mixture (i) a low content of polar and aromatic components; and (ii) separately collecting a stream of a mixture comprising a solvent and at least one of said contaminant components, taking discrete samples of the raffinate stream from time to time, each of which comprises: Analyzing by the described method and inducing a signal indicative of the amount of contaminant components and using directly or indirectly to vary said purification conditions such that the amount of contaminant components in the raffinate is maintained below a selected amount. .