Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/20—Measuring; Control or regulation
  • B01F35/21—Measuring
  • B01F35/213—Measuring of the properties of the mixtures, e.g. temperature, density or colour
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/20—Measuring; Control or regulation
  • B01F35/21—Measuring
  • B01F35/2131—Colour or luminescence
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/20—Measuring; Control or regulation
  • B01F35/21—Measuring
  • B01F35/2132—Concentration, pH, pOH, p(ION) or oxygen-demand
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/20—Measuring; Control or regulation
  • B01F35/22—Control or regulation
  • B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
  • B01F35/2211—Amount of delivered fluid during a period
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/80—Forming a predetermined ratio of the substances to be mixed
  • B01F35/83—Forming a predetermined ratio of the substances to be mixed by controlling the ratio of two or more flows, e.g. using flow sensing or flow controlling devices
  • B01F35/833—Flow control by valves, e.g. opening intermittently
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/85—Investigating moving fluids or granular solids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/26—Oils; Viscous liquids; Paints; Inks
  • G01N33/28—Oils, i.e. hydrocarbon liquids
  • G01N33/2829—Mixtures of fuels

Definitions

• the present invention relates to a method and a device for the preparation of a fuel, in particular for a diesel engine, or of a fuel for a heating installation, by in-line mixing of its various constituents, with optionally incorporation of additives.
• fuels for diesel engines are usually made up of a mixture of various components, generally hydrocarbonaceous, in proportions such that the fuel exhibits certain performance criteria, associated with environmental qualities, in particular during combustion, and responds to precise specifications, relating, for example, to the value of cetane, resistance to cold, sulfur or polyaromatic content.
• these fuels for diesel engines can be produced by the technique known as in-line mixing, according to which the various liquid constituents, as well as any additives, are introduced simultaneously, and continuously, into a line serving as a mixer. .
• the flow rate of the various constituents is controlled and controlled by a computer and the duration of preparation of a batch of fuel can extend over several tens of hours.
• the properties of the fuel produced are checked on various occasions during manufacture and analyzes are carried out for this purpose on samples taken at the outlet of the mixer, or in the storage enclosure during filling. From the results of these analyzes, the flow rates of the components of the mixture as well as any additives are adjusted to align the measured values with the set values.
• PAH Polycyclic Aromatic Hydrocarbons
• benzo (a) pyrene, naphthalene or even thiophenes which are reputed compounds dangerous to the health of living beings and found especially in the constituents of diesel fuels.
• PAHs tend to generate particles and black smoke after combustion in diesel engines, which are then released into the atmosphere with the exhaust gases from the engine and thus present a potential danger to the health of living beings.
• NIR spectrometry Near InfraRed
• NIR spectrometry Near InfraRed
• diesel in an oil refinery, it is common for diesel to come from different units, for example, from distillation atmospheric crude oil, vacuum distillation, visbreaking unit or catalytic cracking.
• the model thus calculated is very sensitive to variations and modifications in the production process markets.
• Burdett Another measurement method, called Burdett, named after its designer, is also proposed for measuring PAHs in petroleum products.
• This non-standardized laboratory method is based on ultra violet spectrometry and measures absorbances at different wavelengths, for example 197, 230 and 260 nanometers (abbreviated to nm). From the intensities thus recorded, after deduction of several response coefficients, the contents of mono-, di- and triaromatic compounds present in the sample analyzed are deduced.
• the Burdett method dates from 1954 and was initially developed to carry out measurements on oils, then, some twenty years ago, it was adapted for fuels by the use of corrective factors, in particular for diesel fuels. It is a fast, repeatable and simple method to implement.
• the UV signal is extremely intense, in particular at 197 nm, and therefore requires significant dilutions, causing difficulties in implementation for online measurement, as well as sources of potential errors for the expression of the results.
• the main difficulty of the method is the adequacy between the concentration to be measured and the length of the optical path of the cell, which requires an adaptation according to the intensity of the signal;
• UV spectrometer an analyzer operating on the principle of measurement by absorbance of ultraviolet radiation
• the invention also aims to provide a method and a device for online mixing of the constituents, and possibly additives, of a diesel engine fuel, in which the measurement of the PAH content of the mixture produced can be rapid, reliable and fully automated and can be used as an automatic adjustment parameter for the fuel preparation unit, for example an in-line mixer.
• the subject of the present invention is a process for the preparation of a fuel, in particular for a diesel engine, or of a fuel for a heating installation, by in-line mixing of its constituents, from different streams having controlled flow rates, with possible incorporation of additives, the fuel having to have for sale a specific content of hydrocarbons of polycyclic aromatic types, process in which a mixer is fed continuously with at least two constituents at controlled flow rates, this process being characterized in that:
• the measurement of the PAH content on the fuel will be carried out in a simple manner using a UV spectrometer, preferably using a double optical beam operating in a wavelength range between 270 and 370 nm and, preferably, between 290 and 330 nm This wavelength range corresponds to the third least intense aromatic absorbance band, thus avoiding, in a spectrometric measurement process, prior dilution of the sample to be measured .
• the spectrometer will measure a reference, or more precisely its baseline, before each measurement of the PAH content on a fuel sample during manufacture.
• This reference will be obtained from a pure product of controlled quality, preferably isooctane, which does not absorb in the UV spectral range as defined above, and which is placed in a cell suitable for this purpose.
• the automation of the spectrometer measurements on the reference product, then on the fuel sample whose PAH content is to be measured, as well as the opening and closing of the shutter means for the sampling of this sample in the measurement cell are made using a device programmed and controlled by a computer.
• UV spectra by any type of mathematical processing and, preferably, by the technique of deconvolution of spectra makes it possible to extract from them the average contributions of each of the types of aromatic molecules (mono-, di- and triaromatic ), and then to evaluate precisely the content of total polyaromatic compounds, that is to say in compounds containing at least two aromatic rings.
• This method like any spectrometric method, is not absolute, and it requires beforehand the fabrication of a model from data obtained by the reference method (EN 12916 or IP 391). Unlike the techniques using an NIR spectrometer, the model thus created is almost universal and can be applied to diesel fuels of various origins obtained by different manufacturing processes.
• the PAH contents of the sample of the mixture during manufacture are determined continuously, from information supplied in the form of electrical signals by the UV spectrometer. For each measurement, the calculated content is then converted, by means of a calculator, into a deviation in PAH content from a previously fixed reference value. The computer then transforms this difference into an electrical signal, which is sent to a computer programmed to control the relative quantities of the various constituents introduced into the mixer.
• the measurement system is therefore easy to automate, since it suffices to control it by at least one programmed automatic device, controlled by a computer, to trigger the measurement sequences of the UV spectrometer, as well as the means of closing the sampling loop intended to isolate the product to be analyzed during the measurement time.
• the measurement time to obtain a PAH content and thus act on the valves for supplying various constituents of the mixture is less than an hour, or even less than ten minutes, which constitutes a considerable advantage compared to the techniques usually used and which require at least one hour to obtain a PAH content, for example the reference method EN12916 / 2000, in order to then be able to act on the settings of the feed rates of the mixture during manufacture.
• UV spectrometer preferably mounted as a bypass on the mixture discharge line
• measuring cell optically connected to the UV spectrometer and to the discharge line, respectively, by lines equipped with sealing means and at least one non-return valve,
• a programmed control means for the functional organs such as those controlling the measurement sequences of the UV spectrometer, the means for shutting off the measurement cell and the flow control valves for the supply lines of the mixer, depending on the results of sample analysis.
• Another application of the invention in the petroleum refining industry, is the continuous control of the flow rates of the streams in charge of a diesel hydrotreating unit (HDT).
• HDT diesel hydrotreating unit
• the invention makes it possible to adjust the various feed flows to obtain a zero difference between the PAH content measured downstream of this HDT and the corresponding setpoint.
• FIG. 1 is a diagram of the entire on-line mixing device of the fuel constituents;
• FIG. 2 illustrates the system for measuring the PAH content on the mixture in progress;
• FIG. 1 is intended for the production of a diesel fuel having predetermined properties, and in particular a prefixed PAH content, by mixing in line of at least two constituents in a mixer 1 and, optionally, in the line 9 for evacuating this mixture to a tank 10.
• Each of the feed lines of the mixer is equipped with an automatic flow control valve 2a - 3a in the different constituents of the mixture, coming from storage tanks 2 - 3
• These various constituents may be, for example and without limitation, alone or in mixture (s), a heavy gasoline derived from catalytic cracker, a light fraction from a crude oil distillation tower, a diesel fuel with a high sulfur content, or a diesel fuel with a low sulfur content from a desulphurization unit, or an LCO, abré Viation from the English "Light Cycle Oil”, diesel fuel from the catalytic cracking of heavy petroleum fractions and therefore containing a high proportion of unsaturated hydrocarbons and in particular polyaromatics.
• FIG. 1 Several online analyzers, only one of which, 22, is shown in FIG. 1, can be connected in a known manner to the discharge line 9 of the fuel produced by means of a sampling loop 21. These analyzers are connected to a control means 11, preferably a commercial computer, itself connected by lines 5 and 6 to valves 2a and 3a, and programmed so as to reduce the difference between the measured values and the values of setpoint.
• a control means 11 preferably a commercial computer, itself connected by lines 5 and 6 to valves 2a and 3a, and programmed so as to reduce the difference between the measured values and the values of setpoint.
• One of these analyzers can be a cetane comparator, as described by the Applicant in FR-A-2 747 322.
• the PAH content of the mixture discharged via line 9 is measured online and the flow rates feeding the mixer 1 and optionally injecting additives at different points (not shown) in line 9 are adjusted so as to bring the measured PAH content closer to the desired setpoint for this value.
• a device 4 for measuring the PAH content of the mixture during manufacture is supplied by a sampling loop of known type and consisting of two separate supply lines 12 and discharge 13 of the the sample to be measured, these two lines being provided with closure means 12a and 13a which can be controlled remotely by the computer 11.
• a non-return valve 23 is installed downstream of the valve 13a on line 13.
• the device 4 is shown in detail in FIG. 2. It comprises a UV spectrometer 14 controlled using software by the computer 11, the latter being able to be relocated from the place of measurement.
• the quartz measuring cell 17 having a dimension of 10 micrometers or, preferably, a measuring cell of the ATR immersion probe type (in English "Attenuated Total Refraction", in French “Réfraction Totale Aténuée") to avoid any dilution of the sample to be measured is supplied by lines 12 and 13 and isolated from the production flow in line 9 by closing the valves 12a and 13a controlled by the computer 11 and the non-return valve 23 on the line 13.
• the cell 17 is connected to the spectrometer 14 by two optical fibers 15 and 16, one of which being intended to send the UV signal to the sample , while the other is used to transfer the signal, after absorption in the sample, to the spectrometer 14.
• optical fibers 15 and 16 make it possible to relocate, if necessary, the UV spectrometer in order to locate it in a place under the conditions more suitable than those recommended by the supplier of the device.
• the spectrometer 14 recalculates its baseline via the calibration cell 20.
• a UV signal is sent by through the optical fiber 18 in this cell containing a product of pure quality, preferably isooctane, and is then returned, after absorption into the reference product, to the spectrometer 14 by the optical fiber 19.
• the UV 14 spectrometer After measurement by the UV 14 spectrometer of the absorption spectrum in the radiation range between 240 nm and 350 nm, and preferably between 290 nm and 330 nm, in the sample and in the reference product, the spectra thus obtained are exploited by mathematical processing from the model programmed in computer 11 to deduce the PAH content of the sample.
• the computer controls the opening of the valves 12a and 13a until their next closing for a new analysis.
• the method and the device according to the invention are simple and reliable in use, require only a short time from the operator and require only a low investment cost.
• the invention therefore provides, for the first time, a PAH measurement system which can be used online in an assembly for preparing a mixture of hydrocarbons, in particular a fuel for diesel engines, by online mixing of the constituents of this fuel.
• a PAH measurement system which can be used online in an assembly for preparing a mixture of hydrocarbons, in particular a fuel for diesel engines, by online mixing of the constituents of this fuel.
• Examples The examples which follow are intended to show the various possibilities for measuring polyaromatics in diesel from the method and the device according to the invention.
• Equipment used is intended to show the various possibilities for measuring polyaromatics in diesel from the method and the device according to the invention.
• the spectrometer used is a device marketed by the company SECONAM under the name Anthélie Senior.
• the UV absorption spectra of the samples, representative of the fuel during manufacture, are measured, in accordance with the invention, in a cell with a low optical path or by the use of an ATR probe (Reflection
• Deconvolution is the decomposition of the UV spectrum of a sample into a certain number of reference spectra (or main components), which are 8 in number at the most and are predetermined. These are UV spectra of pure products (5 in number) and spectra calculated by principal component analysis (3 in number), the objective being, from these 8 spectra, to reconstruct by linear combination any which UV spectrum of diesel oil from the following formula:
• the calibration will allow, after a stepwise multiple linear regression calculation (with Fisher test), to determine the contribution of each of the reference spectra in the expression of the desired result, namely the polyaromatic content.
• Certain reference spectra contribute to the spectrum of the sample and make it possible to deduce the polyaromatic content therefrom.
• the determination of the reference spectra and the calibration require the collection of a certain number of diesel fuel samples and the measurement of their polyaromatic content by the standardized method.
• UV spectra is preferably obtained by any method of correlative calculation between measured spectra and contents obtained by another method of determination and preferably by the so-called deconvolution method.
• the PAH contents (diaromatics and more) of the samples were measured in accordance with the measurement process of the invention, then calculated from the mathematical model previously determined.
• Figures 3 and 4 are two graphs illustrating the correlation between the diaromatic contents or more of the above samples measured by the reference method (contents plotted on the abscissa) and the contents obtained by the process of the invention (contents plotted or ordered), for contents of diaromatics or more comprised respectively between 0 and 50% by weight and between 0 and 25% by weight.
• the UV method as described in the present invention therefore appears to be a reliable alternative for determining the content of diaromatics and more in gas oils. Validation of the UV method The UV method has been successfully validated by the ASTM method
• the invention makes it possible to distinguish, in addition to the overall measurement of diaromatics and more, as presented above (FIGS. 3 and 4): the contents of diaromatics, that is to say of PAH corresponding to the molecules containing 2 aromatic rings (see FIGS. 5 and 6) and
• PAHs containing two or more aromatic rings It also makes it possible to distinguish certain PAHs by measuring diaromatics (two aromatic cycles) and triaromatics and more (3 aromatic cycles and more).
• the implementation, according to the invention, of the automatic control of a mixer of Diesel-type fuels, from the PAH content measured do not pose any particular difficulty for those skilled in the art.
• the result obtained is a better monitoring of the PAH content, thanks to the use of a rapid, effective, inexpensive means of reaction and compensation for any measured drift of the polyaromatic content in a process for the manufacture of diesel fuel by in-line mixing of its constituents.
• the device used in accordance with the invention makes it possible to avoid the drawbacks encountered in the art, such as the greater or lesser participation in the results of the measurements of the presence of EMC or sulfur in the sample analyzed.

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• 2002
  • 2002-09-30 FR FR0212064A patent/FR2845013B1/fr not_active Expired - Fee Related
• 2003
  • 2003-09-18 WO PCT/FR2003/002748 patent/WO2004029592A1/fr not_active Application Discontinuation
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