JPH0833382B2 - probe - Google Patents

Description

TECHNICAL FIELD The present invention relates to a probe used in an apparatus for controlling the stability of a colloidal system.

[Background of the Invention]

Fuel oil can be thought of as a colloidal system, where high C / H ratios of asphaltene are peptized or colloidized as micelles in the oil phase. An important property that distinguishes such colloidal systems from true solutions is the presence of particles larger than the molecule. The stability of colloidal systems typically depends on their ability to keep the particles in solution and prevent aggregation and precipitation. This ability in fuel oil depends on the state of colloidalization of the existing alphaten P
The state of colloidalization depends on both the colloidalizing (or solvent-based) force Po of the fuel oil medium and the asphaltene colloid-forming (or solubility) Pa.

Dr. Van Kerkvoort of the 4th International Conference on Chauffage Industriel held in Paris in 1952, and other papers No.229 (hereinafter simply referred to as "thesis") are fuel oils. A method for evaluating the stability of the fuel oil and the compatibility of the fuel oil mixture by the method of agglomeration ratio test is described. As a result, when the test liquid mixture of aromatic and paraffinic hydrocarbons is added to the fuel oil at a predetermined dilution ratio, the lowest aromatic ratio that does not cause aggregation of asphaltene present in the fuel oil is set. Procedures are given to quantify. This lowest percentage of aromatics is called the agglomeration ratio.

In the above article, this agglutination ratio is quantified by performing time consuming and laborious batch measurements that require a "spot test". In contrast, the present invention provides an accurate instrument for making similar measurements quickly and continuously. According to the above paper, the aggregation ratio (FR, or Floccula
(tion ratio) is quantified by various dilution ratios (DR, ie, Dilution Ratio) of a mixed liquid of aromatic and non-aromatic hydrocarbons (that is, toluene and n-heptane) and fuel oil, and then, In order to avoid asphaltene agglomeration by the mixture of aromatic and non-aromatic hydrocarbons, ie the minimum aromatic content (FR) such that the asphaltene is just colloidalized and the degree of dilution of the fuel oil. A curve is obtained that represents the relationship between. The curve representing this relationship is the agglomeration against the reciprocal of the dilution ratio (ie FR against 1 / DR).
As conveniently plotted. It has been experimentally demonstrated that such plots are linear over a wide range of residual fuel and fuel oil mixing. A linear plot for 1 / DR is preferred because the extrapolation method can be used with better accuracy than a non-linear plot for DR. An example of such a plot is shown in Figure 1a. In FIG. 1a, DR is represented as the volume (volume) of diluent divided by the mass of fuel. The DR is sometimes expressed as the volume (volume) of diluting liquid divided by the volume (volume) of fuel, but there is no problem in converting between these two types of DR.

An important and useful feature of plotting FR against 1 / DR is the intercept on the ordinate (FRmax) and the intercept on the abscissa (DRmin).
By, the state P of colloidalization, the force P of colloidalization P
o, the dissolution performance Pa is given according to the following formula.

Po = FRmax (DRmin + 1) Pa = 1-FRmax P = Po / (1-Pa) = DRmin + 1 In addition, when the mixture is required, the particularly important thing is that
Po and Pa are additive. Therefore, the stability / compatibility of the fuel oil mixture can be calculated from the values of Po and Pa of the components used. For example, in the case of a two-element blend, the following equation is valid:

(1) Poblend = V ₁ Po ₁ + V ₂ Po ₂ (2) Pablend = (V ₁ M ₁ Pa ₁ + V ₂ M ₂ Pa ₂ ) / (V ₁ M ₁ + V
₂ M ₂ ) (3) Pblend = Poblend / (1-Pablend) Here, V is the volume fraction of each mixed component, and M is its asphaltene content. The physical meaning of the quantities in the above equation is summarized as follows.

FR (Agglomeration Ratio): The lowest aromatic content that a mixture of aromatic and non-aromatic hydrocarbons should have in order to dilute the fuel oil to the amount of DR without causing asphaltene agglomeration.

・ DR: Value of the amount of diluting liquid per amount of fuel oil phase (dispersion of asphaltene).

FR = f (DR): This curve represents the agglutination ratio (FR) as a function of the degree of dilution (in aromatic / nonaromatic mixtures at various rates). This curve provides the limiting conditions for fuel oils in which asphaltene can maintain colloidation in alfalten dispersions.

DRmin: the maximum amount of non-aromatic hydrocarbons that the fuel oil can be diluted to (FR = 0) without asphaltene agglomeration.

For infinite dilution of asphaltene dispersions with aromatic / non-aromatic hydrocarbon mixtures: FRmax: aromatic content of the diluent required to keep the asphaltene in colloidal form (at infinite dilution, fuel The colloidalizing power of the oil medium is determined only by the diluent).

1-FRmax: non-aromatic content at infinite dilution that is acceptable without asphaltene agglomeration.

・ Pa: Defined as the solubility of asphaltene, 1-FRm
Corresponds to ax. The better the solubility of asphaltene, the higher the 1-FRmax.

Po: Fuel oil, which is the colloidalizing power of the fuel oil medium, and represents the aromatic component of the aromatic / non-aromatic hydrocarbon mixture having the same colloidalizing power as the fuel oil, expressed as a volume percentage. Can be defined as the aromatic equivalent amount of.

P: The state of asphaltene colloidation in fuel oil, which corresponds to Po / (1-Pa). The better the colloidation state, the higher the colloidization power of the fuel oil medium. It shows that asphaltene can be colloidized satisfactorily.

When P> 1, the fuel oil (mixture) is in a state without dry sludge (a stable fuel in which asphaltene is colloidal), and when P <1, asphaltene aggregates (unstable). Fuel oil).

In assessing the stability and stability limits of fuel oils, and their compatibility with other fuel oils and cutter stocks, under any conditions, aggregates such as asphaltene precipitates Or it is necessary to know if formation occurs. The conventional method for determining the occurrence of agglomeration is the ASTM spot test of Designation No. D2781 or a variation of that test, "Standard Method for Testing Fuel Oil Mixture Compatibility by Spot Test." These conventional methods were time consuming and tedious as they required the production of large numbers of solutions, all of which were checked for the occurrence of aggregation.

[Outline of Invention]

The present invention provides an optical probe that is also adaptable for use in the analysis of rapid, accurate and continuous on-line processes.

The above as well as additional objectives and advantages of the present invention will become apparent in the following detailed written description.

〔Example〕

Interaction of radiation with an object When the radiation from a light source passes through a sample of an optically dense object, the transmitted radiation is the incident radiation and the radiation absorbed or dispersed by the sample. Corresponds to the difference between. The absorbed radiation is either converted to heat or emitted as fluorescence. The incident radiation is (Rayleigh dispersed) by the molecules of the sample,
Alternatively, it is dispersed by small particles or heterogeneous components in the sample (Tindal dispersion).

The transmission of radiation in a colloidal solution depends on the absorption and dispersion state of the medium and is due to the absorption properties and the refractive index of the colloidal particles and of the aggregates formed from them, as well as the incident It is determined by the size of the particles with respect to the wavelength of radiation. With the selection of a radiation source of the appropriate wavelength, significant changes in the transmitted radiation can lead to instability of the colloidal solution (eg fuel oil) or to large particle sizes (eg asphaltene) due to aggregation. To be observed.

Laboratory or batch measurements According to the present invention, the optical probe described in detail below provides a rapid and accurate observation of the occurrence of aggregates, i.e. the formation of aggregates, based on the absorption or dispersion of light by the asphaltene which precipitates, Used in the titration procedure to determine the desired value for FR. The description below relates to a reduction in the intensity of the transmitted radiation as an indicator of aggregation, but aggregation is also indicated by an increase in the intensity of scattered radiation.

Prior art relating to the present invention can be found in the following publications and their bibliography. Hochiru (G.Ho
tier) and Robin (M.Robin) January 12, 1983 "French Fuel Association Review (Revue de1 'Institut
e Franeais du Petrole) "Volume 38, Issue 1," A "
ction de divers diluants sur les produits petrolie
rs ". The present invention relates to improvements in the apparatus for observing the occurrence of agglomeration.

The recorder graph shown in Figure 1b shows how to obtain each point for plotting FR values for 1 / DR as in Figure 1a for a given visbreaker tar fuel. Taka is shown. A small amount of heptane was added stepwise to 22 grams of fuel. An optical probe was used to observe the intensity of light transmitted through the diluted fuel as it was mixed with the fuel in increasing amounts of n-heptane. As more dilute solution was added, the intensity of the transmitted light increased in steps until the turning point of the intensity of the transmitted light (the point indicating that aggregation had occurred). The point at which the maximum increase in transmitted light intensity is reached is just before the aggregation point.
In the lower curve of Figure 1b, the coalescence point occurred when 8 milliliters of n-heptane were mixed with 22 grams of fuel. Thus, there is a relationship of FR = 0 ml aromatics / 8 ml aromatics + paraffins, ie FR = 0, with DR = 0 ml / 22 g, ie DR = 0.36 ml / g. This pair of values is
It was then plotted in Figure 1a with FR = 0 and 1 / DR = 22/8 = 2.75.

Next, the upper curve of Figure 1b was plotted using a starting mixture of 5.5 milliliters of toluene and 11.4 grams of fuel. The observations with the optical probe were again made with increasing n-heptane and mixing with the toluene fuel mixture. Aggregation was observed to occur immediately after the addition of 9 milliliters of n-heptane. Thus,
DR = 14.5ml / 11.4g, ie DR = 1.2.
At 7 ml / gram, FR = 5.5 ml aromatics / 14.5 ml aromatic + paraffin hydrocarbons, ie FR = 0.38. This pair of values is then
Plotted in Figure 1a with FR = 0.38 and 1 / DR = 11.4 / 14.5 = 0.79.

Similarly, a third pair of values for FR and DR were obtained using a mixture of toluene and fuel in different starting proportions.
Plotted in Figure 1a.

For fuels other than the bisbreaker tar fuel represented by FIGS. 1a and 1b, observation was made with an optical probe as shown in FIG. 2a, and several different curves were obtained, and the curves Each gives a pair of values for FR and DR which is a plot of FR values against 1 / DR as in Figure 1a.

The P value and the agglomeration ratio curve are important indicators of the "stability margin" (excess stability) of fuel oil. Such information is particularly useful for optimizing conversion in visbreaking and tar stability.

Paper n- give Po value 0 relates heptane, giving also a negative value with respect to the higher aliphatic hydrocarbon (C ₆ ~C _16). Aromatic has a much higher Po value (up to 1.5), while naphthene has a Po value between aliphatic and aromatic. Po values for mineral oils are said to vary between 0.12 (poor aromatics) and 1.3 (certain aromatic extracts).

Residual fuel Po, Pa and P values and cutter stock P
If the value of o is known, the solubility state P of the intermediate fuel oil mixture can be calculated by the above formula.

In order to observe the occurrence of coagulation based on the absorption and dispersion of light by the precipitated and asphaltene, a suitable radiation source must be selected for the measurement of the intensity of transmitted light in fuel oil. Based on the absorption spectra of the diluted fuel samples, it was decided to use a near infrared light source.
The absorption spectrum showed a minimum absorption at 730 nm, a high absorption in the ultraviolet and a moderate absorption in the infrared band. To avoid interference from ambient light, the near infrared band was chosen rather than the other spectral bands. GaAs: Si light-emitting diode element (IR-LED), which is an inexpensive light source for near-infrared radiation that emits light at around 950 nm.
However, it turned out to be effective for this purpose. The light emitting diode device must have a high luminous flux and a small emission angle. A silicon phototransistor, such as the Phillips BPX25, is used as a light receiving element for infrared radiation transmitted far through the fuel oil sample. As an alternative, a silicon photodiode with an IR filter, such as the Siemens BP104, can be used with suitable optics. The optical system is designed to produce a narrow beam of radiation when the probe is immersed in fuel, a high index non-test medium.

The optical probe 15 in Figure 2a is an example of a probe suitable for observing the occurrence of agglomerations in fuel oils (especially for laboratory use). Another embodiment, shown as 25 in Figure 2b, is suitable for continuous monitor-like process analyzers. The electrical circuitry for the operation of any of the optical probe embodiments is not shown in the figure as it is a standard circuit for the operation of the IR-LED and phototransistor and is not part of the present invention. IR-LEDs emit light when the applied voltage exceeds the forward voltage of the diode (typically 1.4 volts).
The current is properly limited by the use of input resistors. Light is detected by the phototransistor and the voltage developed across the resistor in its output circuit is proportional to the intensity of the detected light.

The probe 15 in FIG. 2a includes a stainless steel housing 13 which serves as a support for the IR-LED 10 and the phototransistor 11 and their lead guide tube. The IR-LED 10 is located at the lower end of the housing 13 and emits infrared rays upward to the phototransistor 11 through the window 19a, the sample slit 12 and the window 19b. All of these elements are set and held in the housing in a fixed positional relationship with each other by casting a resin 17 that can use epoxy or acrylate. Epoxy is often suitable, but
For use in highly aromatic solvents at high temperatures, it is also necessary to use all glass or glass-metal systems. An alternative arrangement of these elements is to place the IR-LED 10 on top of the phototransistor 11 from which the sample slit 12
At the lower end of the housing 13, which is the position across the line, that is, the position opposite to the position shown in FIG. 2a.
11 is to be arranged. However, there are advantages to arranging the elements as illustrated in Figure 2a. I mean,
This is because the arrangement achieves good heat distribution and dissipation within the probe. Heat is mainly generated in the IR-LED 10 and its input resistance, the winding resistor 14, and the arrangement as shown in FIG. 2a is such that there is more spacing between these heat generating circuit elements. I will provide a. The radiation performance of the IR-LED 10 and the sensitivity of the phototransistor 11 are temperature dependent. Maintaining a constant temperature is important to avoid fluctuations in the radiation force and detector sensitivity during the measurement. Since the probe will be partially submerged in a thermostatically controlled oil bath, as will be described later, this requirement is due to the heat inside the probe, as in the arrangement of Figure 2a. It is achieved by improving the distribution and the emission of

The sample slit 12 in this example makes an optical path of about 2 mm length. In embodiments based on scattered radiation rather than transmitted radiation, the radiation detector (ie, phototransistor) is laterally aligned to receive scattered light rather than a linear arrangement of source, sample, and radiation detector. Will be placed.

Fig. 2c shows in detail the structure of the assembly consisting of a light emitting element such as an IR-LED, a slit, and a light receiving element such as a phototransistor, and ensures that the optoelectronic components of the probe are protected from intrusion of aromatic fuel. Or not. IR
The radiation is emitted from the IR-LED10 and is filled in the sample slit 12 through the glass lens 9a of the IR-LED10, the air space 6a, and the translucent window 19a such as glass in the medium (fuel) under test. Go to. Therefore, these constitute a light emitting unit. Then, the light that has passed through the medium is transmitted through the window 19b, which is transparent like glass, the other air space 6b, the optical transistor,
It passes through the glass lens 9b and reaches the phototransistor 11. The IR-LED 10 is housed in a tubular housing 7a and the phototransistor 11 is housed in a tubular housing 7b. The inner seal 17a and the outer seal 17b, which are formed by casting resin and seal the slit 12, cooperate with the translucent light emitting portion window 19a, the light receiving portion window 19b, and the housing to form a component (IR -LED10 and phototransistor) and light emitting part space 6a and light receiving part space 6b are sealed and protected from direct contact with the medium, that is, fuel oil. FIG. 2c also shows a seal 17c that protects the printed circuit board 8 at the slit 12 from the electrical connection between the light emitting portion window 19a and the light receiving portion window 19b. The first exposure to aromatic fuel oil occurs in the glass windows 19a and 19b and the outer cast resin seal 17b that fills the edges of the stainless steel housing 13; these outer seals 1
7b can be easily replaced. If such a seal failure occurs, it does not result in a probe failure. This is because the probe optoelectronic components are protected by the inner seal 17a that serves as a backup.

Figure 2c also shows the optical characteristics of the probe. Near infrared (I
The light of R) is condensed and projected into a conical light beam with a small irradiation angle from the light emitting portion, and is condensed into a conical light beam with a small incident angle in the phototransistor. Focuses the available IR radiation into a small cross section, allowing IR per unit area
Maximum signal-to-noise (S /
N) ratio can be achieved. For this purpose, I
It will be appreciated that it is desirable to narrow the R light beam. This is especially desirable when sensing radiation transmitted through highly absorbent media such as fuel oil. Furthermore, it is possible to reduce the perspective angle of the phototransistor by concentrating all of the emitted IR light into a small cross section, and the smaller the perspective angle of the phototransistor, the more scattered and reflected it is. This is advantageous because it reduces the unwanted side effects that result from ghost light such as radiation. A further advantage of limiting the angle of the IR cone beam emitted from the light emitting part is that it minimizes the angle of incidence of the IR light on the glass window and also the amount of light reflected from the glass window surface. To reduce the ghost light. It is desirable to reduce such ghost light as much as possible because it causes a disadvantage in that a current similar to a dark current is passed through the phototransistor to limit the operating range of the probe. Further, some light leaks from the edge of the light emitting unit window 19a, and a part of this light becomes ghost light reaching the light receiving unit. This ghost light is a seal 17c against the slit,
The light transistor 11 is reached via 17b and 17a. Therefore,
It is important to minimize the light arriving by such "ghost" paths. To provide additional protection against light transmitted by such "ghost" paths, slit seals are said to be strongly absorbing (ie by adding carbon black to the epoxy sealant). It

The air space 6a between the lens 9a and the window 19a acts as an "air lens", and the lens 9a is used to thin the light beam.
Help make the function more effective. If the light emitting part space 6a as this "air lens" does not exist and the light generated from the lens 9a directly enters the sample oil having a high refractive index, the characteristic of thinning the beam of the lens 9a is invalid. I will be disappointed. The same reason applies to the light receiving portion space 6b as the "air lens" of the phototransistor 11.

 The printed circuit board 8 is also shown in Figure 2c.

The use of probe 15 in making laboratory measurements of fuel oil stability is shown in FIG. Probe so that fuel oil stays in the slit 12 or flows through it.
The lower end of 15 is immersed in fuel oil sample 30. The occurrence of agglomeration in the fuel oil within the slit 12 is observed as a decrease in the intensity of the light transmitted from the IR-LED 10 to the phototransistor 11. IR-LED with electrical connection as shown in Figure 2a
10 and phototransistor 11. 16a is IR-LE
The electrical lead to D10 and the lead 16b to the phototransistor 11.

The stability of the fuel oil, as indicated by the conditions necessary to initiate the agglomeration, is determined by the fuel oil or fuel oil contained in a container 31 surrounded by a water bath 32, as shown in FIG. It is determined by immersing the probe 15 in a sample 30 of the diluent mixture. Water bath 32
Is placed on a hot plate 34 and maintained at a predetermined temperature by monitoring the temperature with a thermometer 35. To fill the slit 12 of the optical probe with a representative sample, the sample 30 is continuously stirred by means such as a magnetic stirrer 33. A suitable titration fluid such as n-heptane is
Added using titration billet 36. The power supply 37 supplies power to operate the IR-LED. A recorder or millivolt voltmeter 38 measures the output from the phototransistor 11 of the optical probe 15.

Continuous Measurements The optical probe and titration procedure described above for determining fuel oil stability characteristics is also useful for continuous monitoring process analysis. FIG. 2b shows an optical cell 25 which is an example of an optical probe suitable for process analysis, and the IR-LED 20 and the phototransistor 21 corresponding to the IR-LED 10 and the phototransistor 11 in the optical probe 15 of FIG. 2a. Including and Optical cell
25 includes a short glass pipe section with an end having a flange-like means for attachment to a sample pipe for process analysis, the narrowed or slit section of which
IR-LED 20 is arranged on one side of 22 and phototransistor 21 is arranged on the other side. Infrared radiation from IR-LED20 crosses the fuel oil sample in slit 22 and is a phototransistor.
21. Again, the occurrence of agglomeration in the fuel oil stream in optical cell 25 is observed as a decrease in the intensity of light transmitted from IR-LED 20 to phototransistor 21. The IR-LED 20 is supported in a support 23, the electrical leads of which are shown at 26a. The phototransistor 21 is supported in a phototransistor housing 28, the electrical leads of which are shown at 26b.

Figure 4 shows a line 40 with such a process analyzer.
A method of monitoring the stability of the fuel oil passing through will be described. The oil sample in line 40 is continuously flowed as a constant flow sample stream A via a sample loop or conduit 41. Sample is drawn into the loop via inlet valve 42 and exits the loop via outlet valve 43 to line 40.
Return to. The loop sample is driven at a constant flow rate by pump 44 under the control of flow controller 45. The sample is then probed (as shown in Figure 2b) or an optical cell.
25a, static mixer 46b, optical cell 25b, static mixer 46
(1), optical probe 25 (1), ..., Sequential flow, static mixer 46 (n), optical probe 25
Get out of (n).

The non-aromatic diluent is pumped to line 47 by pump 55. The flow of the non-aromatic diluting liquid is divided into two streams, one of which is a flow controlled by a flow controller 49 that increases the dilution liquid, and the other is a flow controller 48 for performing dilution beforehand. It is a controlled flow. The flow controlled by the flow controller 49 is a constant flow C, which is a branching device for producing n equal flows 1,2 ... n-1, n shown in FIG. Enter in 50. Each of the n equal streams is introduced into its loop 41 at its discrete location as described below. Stream 1 is an optical probe
From 25 (b) to static mixer 46 (1),
Join the sample in loop 41. Stream 2 likewise enters the loop between exiting the optical probe 25 (1) and entering the next static mixer. The flow rates of non-aromatic diluent added at each stage are all equal, and finally the bypass loop
This is the sample flow at 41. Then, in the loop, it is thoroughly mixed with the sample, and the mixture is mixed with the optical probe 25.
(1) ... 25 (n) are sequentially passed.

As with the laboratory use example shown in FIGS. 2a and 3, the occurrence of asphaltene agglomeration in the flow in the process analysis loop 41 was observed in several optical cells 25. As is seen, it is optically observed as a reduction in the intensity of the transmitted light. Data is collected regarding the observation of the transmitted light intensity, and the aggregation point is determined based on the maximum flow rate determined from the transmitted light intensity, as described above for laboratory or batch measurements. Sent to a data logger 56 programmed to do so. The output of the data logger 56 can also be communicated to a microcomputer 57 that is programmed to allow process control (ie, control of pyrolyzer temperature).

If it is desired to preset the sample flowing in the loop 41 to a state where the aggregation point occurs within the range of n-step increase, the flow of the non-aromatic diluting liquid in the line 47 is changed to the flow rate. Constant flow B from branch controlled by controller 48
Can also be added as. Constant flow B is a static mixer 46 (b) where the sample exits the optical probe 25 (a).
Added during the loop before entering.

A wash fluid line 51 with a wash fluid inlet valve 52 is also provided, if desired, to wash the entire bypass loop 41 with aromatic diluent. Wash line 51 can also be used for pre-dilution of the sample in loop 41 with aromatic diluent.

After being analyzed, the sample flowing in the loop 41 can be returned to the fuel line 40 via the outlet valve 43 and also to the slop line 53 via the slop (dirty liquid) outlet valve 54. You can put it back inside.

Again, FIG. 4 shows a process analysis to quantify the stability margins of fuel or residual oil quality improvement stocks or products, which automatically adapted the laboratory-type optical probe and titration procedure described above. Will be described. The process analyzer can be mounted on the bypass loop of the process or feed line. Constant flow rate A of the flow to be analyzed
Are sent along the optical probe or cell number (a, b, 1-n), each containing the same basic elements used in the laboratory procedure described above. After being prediluted with a constant flow rate B of non-aromatic diluent, the mixture homogenizes the fluid,
It is passed through a static mixer to allow the required reaction time. The light transmitted through the undiluted fuel is checked by the optical cell 25 (a) and the pre-diluted fuel is checked by the cell 25 (b). After cell 25 (b), the fuel is serially diluted in a series of steps with a constant flow rate C / n of non-aromatic diluent in each step. After each dilution step, after passing through the static mixer associated with that step, the fuel undergoes a check of the intensity of the light transmitted by the optical cell associated with that step. Increasing the size of the asphaltene particles (causing agglomeration) results in increased absorption of light. Coagulation points are marked when, after dilution with a non-aromatic diluent, the intensity of the transmitted light is reduced compared to the normal intensity of light during sequential dilution of the fuel. For fuels exhibiting asphaltene precipitation at the reciprocal of the dilution ratio equal to A divided by the quantity B + 9 (C / n), the typical transmitted light intensity level detected by the optical cell is 5th. As shown in the figure. The aggregation point quantified in this way is A + quantity B +
It lies between the value divided by 8 (C / n) [the reciprocal of the dilution ratio at which no precipitation occurs] and the value obtained by dividing A by the quantity B + 9 (C / n).

Viscosity Mixing Optical probes are useful in determining the amount of diluent that can be mixed with fuel oil fuel without exceeding stability limits. FIG. 1c shows the titration curve of transmitted light intensity as measured by the probe against the amount of gas oil added to the heavy fuel oil. The onset of aggregation is marked by reaching the maximum slope or slope in the titration curve (the maximum power increase between two successive additions, which is
(The same criteria used in Figures 1a and 1b).

Storage stability and compatibility With storage stability of residual fuel, other fuel oil, and further,
Their compatibility with gas oils is primarily determined by the state P of asphaltene colloidation present in such systems. The state of colloidalization depends on the solubility Pa of asphaltene and the force Po of colloidalization of the oil matrix. These parameters can be derived from the linear relationship between the agglutination ratio (FR) and the reciprocal of the dilution ratio (DR).

Another simple way to derive these parameters is
By using the linear relationship shown in the toluene-heptane graph in Figure 1d. The intercept on the n-heptane axis is
Provides a safety margin (DRmin) for fuel oil. The slope of the safety line depends only on the asphaltene solubility Pa.

Inclination = (1-Pa) / Pa In practice, an inclination close to 1 is usually found. (Pa = approx. 0.
Five).

For fuel oil without stability margin (DRmin = 0; P = 1), a straight line through the origin is obtained in the toluene-heptane plot.

[Brief description of drawings]

FIGS. 1a, 1b, 1c and 1d are graphs showing whether the stability of colloidal system is plotted as a graph from the measurement by the device of the present invention, and FIG. 2 and 2b are views showing probes or cells used in the laboratory, batch measurement, and continuous measurement, respectively, and FIG. 2c is a view showing details of the probe shown in FIG. 2a. FIG. 3 is a diagram showing an apparatus of the present invention for performing a laboratory or batch measurement, and FIG. 4 is a diagram of the present invention for performing a continuous measurement such as in on-line process control. FIG. 5 is a diagram for explaining the device, and FIG. 5 is a diagram showing data obtained by the device of FIG. 4 from which data on the stability of colloidal system can be determined and which can be used for process control. Is. 6a, 6b ... Space, 9a ... Lens for light emitting element, 9b ... Lens for light receiving element, 10 ... Light emitting element (IR-LED), 11 ... Light receiving element (optical transistor), 12 ... Slit, 13 ...... Housing, 15 ...... Probe, 17a, 17b, 17c ...... Sealing means, 19a ...... Light emitting part window, 19b …… Light receiving part window, 30 …… Sample, 31 …… Container, 32 …… Water bath, 33 ...... Magnetic stirrer, 34
...... Hot plate, 35 ...... Thermometer, 56 …… Data logger, 57 …… Microcomputer.

Claims (3)

[Claims] 1. A probe which is used for the evaluation of a colloidal system in a dark hydrocarbon such as heavy oil, in which at least the tip side is immersed in the dark hydrocarbon to be tested, which comprises a light emitting part and And a light receiving portion that receives the light of the above through the dark hydrocarbon to be tested, the light emitting portion and the light receiving portion are held in a fixed positional relationship with each other, and an elongated housing that is housed near the tip side (1
3), and the light-emitting unit includes a light-emitting element (1
0), a light emitting element lens (9a) for condensing light from the conical light beam at a small angle, and a path for the conical light beam to travel and to effectively collect light by the light emitting element lens. Sealed light emitting part space (6a)
And a light emitting window (19a) which is transparent and perpendicular to the longitudinal axis of the housing for separating the light emitting space from the dark hydrocarbon and advancing the light beam passing through the light emitting space to the dark hydrocarbon. ) Are provided in the light receiving part, and a light receiving part window (19b) that is transparent and is substantially parallel to the light emitting part window (19a) for receiving the light beam that has passed through the dark hydrocarbon, and the light receiving part. A sealed light receiving part space (6b) which is separated from the dark hydrocarbon by a window and provides a path for a received light beam to travel, and a light receiving part lens which receives the light beam passing through the light receiving part space and further condenses it. (9b) and a light receiving element (11) for detecting the light collected by the light receiving lens, and the light emitting space (6a) and the light receiving space (6b) are sealed from the dark hydrocarbons. Light emitting part window A narrow slit (12) which is filled with the dark hydrocarbon during use is formed between the light receiving portion window (19a) and the light receiving portion window (19b), and a seal attached to the slit is opaque and has a large light absorption property. From the window (19a) to the light receiving window (19a)
A probe characterized in that it is configured to prevent ghost light from entering. 2. The probe according to claim 1, wherein the light emitting section is arranged on the one end side of the housing, and the light receiving section is arranged on the other side of the housing. A probe characterized by. 3. The invention according to any one of claims 1 and 2
In the probe according to the item (3), the seal attached to the slit includes the light emitting unit window (19a) and the light receiving unit window (19b).
And a means for sealing the light emitting portion space (6a) from the medium in the slit, and a means for sealing the light receiving portion space (6b) from the medium in the slit. Probe to do.