Automatic correction of smoke point

Abstract

A test apparatus and method for determining the smoke point of a hydrocarbon. The apparatus comprises: a device for determining the smoke point, which conforms to the specifications of ASTM D1322-19 standard or equivalent; an imaging device for acquiring a series of digital images of the flame; an ambient relative humidity sensor for measuring the relative humidity; an ambient temperature sensor for measuring the temperature; a computer system linked to the imaging device, the humidity sensor and the temperature sensor, which is programmed to analyze the digital images from the imaging device to measure the flame height, and to calculate the absolute humidity using the temperature and relative humidity measured by the temperature sensor and the humidity sensor, and to correct the measured flame height according to the difference between the calculated absolute humidity and the normalized absolute humidity, and preferably to correct the measured flame height according to the difference between the pressure during the flame height measurement and the normalized pressure.

Description

Technical Field

[0001] The present invention provides a method and apparatus for correcting the measured smoke point by taking into account ambient humidity and temperature, as well as optional pressure. Background Technology

[0002] The smoke point of hydrocarbons is a characteristic routinely determined in refinery laboratories, for example, on kerosene, aviation fuel, kerosene, etc. This characteristic is an important parameter because it is directly related to the hydrocarbon composition of the specific fuel being tested. In practice, the higher the carbon (C) to hydrogen (H) ratio (C:H), and therefore the lower the content of aromatic compounds, the higher the smoke point, and the better the fuel performs during combustion. In other words, the smoke point is quantitatively related to the potential radiative heat transfer, and because this heat transfer exerts a strong influence on the temperature of metal components, the smoke point becomes a predictor of the lifespan of those metal components.

[0003] However, a drawback of using smoke point as a predictive indicator is its difficulty in measurement. Typically, standardized analytical methods are used for detection (e.g., the method described in ASTM D1322-19, Standard Test Method for Smoke Point of Kerosene and Aviation Turbine Fuels, ASTM International, West Kosohawken, PA, 2019, www.astm.org, incorporated herein by reference, and its equivalents, such as ISO 3014, IP57, and NF M 07-028), and then the maximum flame height of the tested hydrocarbon sample without smoke formation is measured. These measurements are typically expressed in millimeters (“mm”) and accurate to almost one-tenth of a mm. There are no (or very small) differences between the ASTM D1322-19 standard and standards such as ISO, IP, NF, GOST, and JIS.

[0004] In this measurement, the hydrocarbon test sample is burned in a wick lamp containing a candle and a wick (also described in ASTM D1322-19). The test involves setting the wick height and changing the candle position to gradually adjust the flame height and appearance in a subsequent sequence of flame appearances. The flame height and appearance change slowly from a state with a relatively elongated and bouncy tip (a sharp tip with an upwardly concave side, and a light smoke at the top) to a shorter flame height (the flame tip is completely rounded). Between these two flame states, the test operator must also distinguish two other intermediate flame shapes: one with an elongated point and a concave edge at the top, and another where the flame tip just disappears and the flame is slightly rounded (slightly blunted) and there is no smoke. When the flame has the final appearance, the operator or an automated measuring device (using digital imaging) records the flame height on a scale in mm located inside and at the rear of the lamp. The flame height at the smoke point was observed three times individually by repeating the flame appearance sequence a total of three consecutive measurements. If these measurements varied within a range greater than 1.0 mm, the test was repeated with a new sample and another wick. The final value of the smoke point of the analyzed sample was the average of the three consecutive measurements calculated to be closest to 0.1 mm.

[0005] However, like all such analytical methods, manual methods for measuring smoke point, as defined in ASTM D1322-19, have limitations in terms of accuracy. For example, the test operator often struggles to determine the correct appearance of the flame and the precise moment to measure its height on the ruler. While certain procedures and precautions should be implemented to ensure quality results when measuring flame height, their application is entirely dependent on the test operator. Therefore, the repeatability and reproducibility of standardized tests are 2 mm and 3 mm, respectively.

[0006] U.S. Patent No. 7,829,343 to Reminiac et al. discloses an automated method and apparatus for determining the smoke point of hydrocarbons according to ASTM D1322 or its equivalent, as an improvement over manual methods. US7,829,343 discloses a method and apparatus for determining the smoke point of hydrocarbons, comprising identifying specific aspects of the flame in different aspects of the flame according to the position of the burner in a lamp, and reading the height of the flame on a scale in mm, in different steps defined by ASTM D1322 or its equivalent. The method is characterized by acquiring and recording a series of digital images of the flame at sufficiently close intervals using a digital camera or the like, so as to detect sudden changes in the flame shape by analyzing these digital images, and measuring the height of the flame when the flame shape changes suddenly. This height is considered the smoke point of the tested hydrocarbon. A commercial apparatus employing the patented system is the AD System Automatic Smoke Point SP10. The AD System Automatic Smoke Point SP10 uses a system that adjusts the flame size associated with a camera observing the flame. When the flame reaches the shape described in the test method, the SP10 stores and reports the height of the flame. SP10 provides a judgment method in ASTM D1322: Section 6.2.2 of ASTM D132-19 states, "Since the resolution of digital cameras is far superior to that of the human eye, smoke point should be measured by automatic equipment when available. If there is a dispute between the results of the manual method and the automatic method, the automatic method should be considered."

[0007] However, smoke point measurements obtained using the current system and methods may be adversely affected by the environmental pressure conditions experienced or encountered at the test site. Therefore, atmospheric pressure is considered when calibrating the current system.

[0008] In manual equipment, the operator shall verify the equipment calibration according to Section 10 of ASTM D 1322-19, or according to Section 10.1.3 of ASTM D 1322-19, before the first use of the day, if necessary, according to Section 10.1.1 of ASTM D 1322-19. Recalibrate when the equipment or operator changes, or when the pressure reading changes by more than 0.7 kPa. Calibrate the equipment by testing two reference fuel mixtures specified in Section 7.4 of ASTM D1322-19 using the procedure specified in Section 11 of ASTM D1322-19, and, if possible, consider the smoke point of the sample equivalently. If this is not possible, use two test blends whose smoke points are closest to the sample smoke point. Determine the correction factor f (sometimes called the lamp factor) for the device from the following equation (1):

[0009] f = [(As / Ad) + (Bs / Bd)] / 2 (1)

[0010] in:

[0011] AS = Standard smoke point of the first reference fuel mixture

[0012] AD = Smoke point determined for the first reference fuel mixture.

[0013] BS = Standard smoke point of the second reference fuel mixture, and

[0014] BD = Smoke point determined for the second reference fuel mixture.

[0015] In the method using automated equipment, in accordance with Section 10 of ASTM D1322-19, the automated equipment can automatically calculate the correction factor f using stored reference data according to equation (1). The equipment should have a calibration database for storing reference fuel mixture values ​​specified in Table 1 of ASTM D1322-19.

[0016] Table 1 Reference Fuel Mixtures

[0017]

[0018]

[0019] Each calibration test performed with a reference fuel mixture should be additionally stored in the database along with the atmospheric pressure observed during calibration. Section 10.2.1 of ASTM D1322-19 discloses that automated equipment should have the capability to automatically calculate the correction factor f according to equation (1) by automatically selecting the reference fuel mixture value specified in Table 1 from its calibration database, using the procedure specified in Section 11 and the calculation specified in Section 12, and, where possible, to equally consider the smoke point of the sample. If this is not possible, the results of the two test mixtures whose smoke points are closest to those of the sample should be used. A digital camera and associated software replace the operator's eye in observing the flame. Therefore, it is not necessary to recalibrate the automated equipment when the operator changes.

[0020] Section 12 of ASTM D1322-19 discloses the calculation of smoke point (accurate to 0.1 mm) using the following equation (2):

[0021] Smoke point = L xf (2)

[0022] in:

[0023] L = the average of three individual flame height readings, and

[0024] F = Correction factor in Section 10.1.2 of ASTM D1322-19.

[0025] The operator performs the calculations using manual equipment. However, automated equipment calculates the smoke point automatically.

[0026] However, for automated equipment, ASTM D1322-19 Section 10.2.2 discloses recording atmospheric pressure and checking in the calibration database that the instrument has been calibrated at the recorded pressure + / - 0.7 kPa. If no calibration value exists for the seven blends specified in Table 1 at the observed pressure + / - 0.7 kPa, ASTM D1322-19 Section 10.2.2 discloses calibrating the equipment according to Section 10.2.3. If a calibration value exists for the seven blends specified in Table 1, in other words, if the instrument is calibrated at the observed pressure, ASTM D1322-19 discloses checking the equipment according to Section 10.2.4. The automated equipment stores the smoke point obtained using reference fuel at different atmospheric pressures. Therefore, if the instrument is calibrated at the observed pressure, recalibration is not required when a change greater than 0.7 kPa occurs in the atmospheric pressure reading. Based on the pressure input at the start of the test, the equipment will automatically use the correct stored value obtained using the fuel mixture. If the correct value has not yet been stored, the device will prompt the operator to calibrate again at the observed pressure in accordance with Section 10.2.3 of ASTM D1322-19, which discloses calibrating the device by testing the seven reference fuel mixtures specified in Section 7.4 using the procedure specified in Section 11.

[0027] Therefore, if the pressure change exceeds 0.7 kPa (manual method, ASTM D1322-19 Section 10.1) or if the calibration database of the automated equipment does not have a calibration value stored within 0.7 kPa at atmospheric pressure at the time of testing (ASTM D132-19 Section 10.2.2), the conventional method requires the device to be recalibrated.

[0028] Even if the (automatic) testing equipment records calibration values ​​at different atmospheric pressures, there is still a limitation that calibration must be performed with seven different reference fuel mixtures before the smoke point of a specific fuel sample to be tested is performed when no calibration values ​​are saved (stored) at pressures close to the current pressure.

[0029] For example, since the smoke point value of the fuel sample to be tested is not known in advance, it is necessary to (theoretically) make all the values ​​of seven different reference fuel mixtures at atmospheric pressure (i.e., the calibration values) equivalent to the values ​​measured during the test procedure. This is tedious because it is difficult to make all the calibration values ​​have a step size of 0.7 kPa, so calibration at the correct pressure is often required before the test method can be performed. To this end, many test operators simplify the calibration process by inputting pressure values ​​with existing calibration values ​​(i.e., "cheating").

[0030] It is desirable to provide an improved automatic calibration apparatus and method for smoke point measurement. Summary of the Invention

[0031] ASTM D1322-19 does not describe any corrections based on humidity or temperature. The ASTM D132-19 specification stipulates that automated equipment should have a calibration database to store reference fuel mixture values ​​specified in Table 1 to correct for atmospheric pressure at the time of measurement. The ASTM D1322-19 calibration method is primarily used to compensate for variations in atmospheric pressure. This also includes corrections for inherent parameters of each device, but these inherent parameters do not change over long periods. Using manual or currently automated equipment, the operator measures the current atmospheric pressure using a separate barometer and manually enters the measurement into the device. ASTM D1322-19 measurement corrections are based on a comparison of deviations measured on its reference products (reference fuel mixtures, mixtures 1 through 7) under the same conditions as the test performed. If the test is performed under the same conditions, the correction is accurate. However, this is often not the case in practice, as calibrations are stored and therefore based on tests performed days, months, or even years prior to the current test, and only atmospheric pressure is recorded at the time of the calibration test, not other variables that might affect the results, such as humidity, temperature, or other parameters.

[0032] Calibration is used to compensate for measurement deviations by comparing the measurement deviation with a reference pressure of 101.3 kPa. However, a source of deviation that can affect the final result of the smoke point measurement is the atmospheric humidity at which the calibration is performed. Conventional apparatus and methods do not measure and record humidity conditions, and therefore they do not reduce or eliminate humidity-induced deviations or errors. Thus, even when it is known that specific tests on kerosene are performed at the same pressure as during calibration or simultaneously with calibration, humidity conditions may differ (because humidity is not measured and recorded). This will introduce smoke point measurement errors and alter the repeatability of the test.

[0033] When measuring smoke point according to the test method, air humidity and ambient temperature can significantly affect (interfere with) the results. For example, it is difficult to perform the test method with known test equipment in areas with high humidity (e.g., Southeast Asia during the monsoon season) because measurements during calibration are outside the authorized limits of the ASTM D1322-19 standard.

[0034] This invention automatically corrects for the influence of atmospheric conditions on smoke point measurement using the ASTM D1322-19 standard or its equivalents (e.g., ISO 3014, IP57, NF M 07-028, etc.). There are no (or very small) differences between the ASTM D132-19 standard and its equivalents such as ISO, IP, NF, GOST, JIS, etc. This apparatus and method conform to these equivalent standards. Therefore, an apparatus for determining the smoke point that conforms to the ASTM D1322-19 standard is also an apparatus for determining the smoke point that conforms to its equivalent standard. Therefore, a method for determining the smoke point that conforms to the ASTM D1322-19 standard is also a method for determining the smoke point that conforms to its equivalent standard.

[0035] This invention automatically corrects the effect of humidity on smoke point measurement. Preferably, this invention automatically corrects the effects of humidity and pressure on smoke point measurement.

[0036] This invention provides an apparatus and method for automatically correcting smoke point measurements (flame height is typically measured in millimeters) according to atmospheric conditions, such as automatically correcting for ambient (atmospheric) air temperature and humidity. Specifically, this invention considers humidity to eliminate errors caused by humidity variations. The amount of water molecules in the air disrupts kerosene combustion and thus the smoke point value. The density of water vapor in the air is called absolute humidity, expressed in kg / m³. Humidity sensors provide relative humidity (RH) expressed as %RH. The calculation of absolute humidity from relative humidity is described in detail in the art. Calculating absolute humidity from relative humidity involves simultaneously measuring air temperature and atmospheric pressure with the relative humidity. Therefore, the apparatus of this invention has sensors that measure relative humidity, air temperature, and typical atmospheric pressure. However, it should be noted that atmospheric pressure has a very small effect on the calculation of absolute humidity (less than 0.1% for a change of 250 hPa).

[0037] This invention corrects for variations in atmospheric conditions and other factors to allow for correction of all influencing factors. This invention automatically corrects measured smoke point values ​​for humidity and temperature. This invention corrects measured smoke point values ​​(flame height, mm) based on the difference between calculated absolute humidity and normalized absolute humidity. Preferably, this invention operates at 7gr / m 3 The normalized smoke point is chosen for measurement at absolute humidity because it is a typical value for the reference mixture. However, this can be another value, typically 0 to 40 gr / m.3 The invention corrects for the smoke point value (flame height in mm) measured in existing calibrations based on the difference between the current atmospheric pressure measured by an external barometer or integrated sensor and the pressure recorded during calibration. Pressure measurements are also used for real-time correction of flame height measurements and to normalize the smoke point measurement at 101.3 kPa (also known as 1013 hPa or 1 atm). The invention preferably selects a normalized smoke point measurement at 1013 hPa because it is a typical value for the reference mixture. However, this can be another value, typically a normalized value of atmospheric pressure between 800 and 1100 hPa on Earth.

[0038] This invention also integrates an air humidity sensor and an ambient temperature sensor into the device, using the measured values ​​to correct the flame height measurement. The correction can be applied in real time during flame height measurement or on the smoke point result. Furthermore, an atmospheric pressure sensor can be integrated into the device. However, atmospheric pressure can also be read from an external barometer and its value input into the device. The integration of the pressure sensor primarily avoids operator errors when reading the barometer or typing errors during input. The integration of the pressure sensor also ensures better traceability of the test.

[0039] Preferably, the present invention corrects not only the measured smoke point value for humidity and temperature, but also for atmospheric pressure, to avoid pressure changes exceeding [a certain threshold] during each calibration period. + Calibration must be performed (or has been performed and stored previously) at 0.7 kPa.

[0040] The pressure calibration of this invention differs from the calibration currently applied by the ASTM D1322-19 standard. By specifying that recalibration must be performed when the pressure change is greater than 0.7 kPa, the ASTM D1322-19 standard implicitly establishes a link between the calibration process with a reference mixture and atmospheric pressure.

[0041] However, as mentioned above, smoke point results are affected by various factors. There are atmospheric pressure, humidity, and errors inherent to the camera used to measure the smoke point, such as camera or lens malfunctions or adjustment tolerances.

[0042] The ASTM D132-19 standard uses a lamp factor "f" to account for errors inherent to the camera used to measure smoke point, such as camera or lens malfunctions or adjustment tolerances, and primarily compensates for pressure variations by requiring recalibration when the pressure change exceeds 0.7 kPa. However, improvements are needed to address other atmospheric factors. A better way to accommodate pressure variations is also required to avoid the need for recalibration when the pressure change from the initial calibration time to the time of test sample measurement exceeds 0.7 kPa.

[0043] The ASTM D132-19 standard corrects smoke point measurements by comparing (and equivalently considering) the results obtained with two reference mixtures, and applies the correction to the average of the measurement deviations obtained on the mixtures relative to the reference values ​​of those mixtures.

[0044] If measurements of the mixture (called calibration) and the kerosene to be tested were performed under identical conditions—namely, the same pressure and humidity—this would be accurate. However, the ASTM D1322-19 standard does not account for humidity and only requires repeated calibration to maintain near-atmospheric pressure between tests and calibrations. This can introduce errors in kerosene smoke point measurements.

[0045] For example, if at a pressure of 980 hPa and 9 gr / m 3 Calibration was performed at a humidity level of 980 hPa and a pressure of 21 gr / m. 3 If a smoke point test is performed at a humidity level of 980 hPa and 9 gr / m, then a standard system should be used, and the results will be obtained from the results corresponding to 980 hPa and 9 gr / m. 3 The value X is corrected under certain conditions. This would be incorrect because the value X does not take into account the 12gr / m difference between calibration and smoke point measurement. 3 Differences in humidity.

[0046] The inventors have discovered that humidity has a very strong influence on results and poses a significant problem for test reproducibility. To correct this problem, the present invention measures humidity during or simultaneously with calibration and testing and applies a humidity correction factor f. h Humidity was taken into consideration. Therefore, the inventors investigated the effect of humidity on smoke point results (and only humidity, while keeping other variables that might have an effect constant). From this study, the inventors derived an absolute humidity correction formula, which, based on absolute humidity, uses a correction factor f. h To correct the measurement results, an absolute humidity correction factor f is used. h The humidity correction formula can be determined empirically based on data. Potentially, a humidity correction factor f can be used. h The humidity correction formula can be determined theoretically. This humidity correction formula is not taught or recommended by the standard ASTM D1322-19 method.

[0047] Therefore, a first aspect of the present invention is to determine absolute humidity using measurements of relative humidity, ambient temperature, and ambient atmospheric pressure. The calculation of absolute humidity is well known in the art. However, the inventors have noted that atmospheric pressure has a negligible effect in such measurements of absolute humidity. Although not preferred, some methods simplify the calculation of absolute humidity by assuming a standard pressure, such as 10¹³ hPa (1 atm), instead of using the measured atmospheric pressure.

[0048] The present invention then applies humidity correction to the smoke point (flame height) measurement based on the difference between the absolute humidity and the normalized absolute humidity value to obtain comparable measurements in which the influence of absolute humidity is eliminated.

[0049] Therefore, even when calibration and testing are performed under different humidity conditions, the present invention makes the standard method of ASTM D1322-19 applicable to the work.

[0050] However, problems still exist due to the need for calibration at pressures close to the test pressure, and therefore calibration usually has to be performed before testing.

[0051] A preferred second aspect of the invention addresses the aforementioned problem. Its purpose is to eliminate the need for recalibration whenever the pressure change exceeds 0.7 kPa.

[0052] A second aspect of the invention is that a single calibration is set only for the seven reference mixtures, and the calibration values ​​are recalculated based on the pressure by applying a pressure correction factor fp, enabling their use regardless of atmospheric pressure during the measurement. This is only possible if the influence of humidity is removed in the first aspect of the invention. In the context of this specification, the term "during the test" includes concurrently with or within the same period as the test. Concurrently includes the day of the test or within + / - 1 hour of the test.

[0053] However, even when applying the first aspect of the invention to correct for humidity, the effect of pressure on the results is unknown, as is how to correct for the effect of pressure on the results. The ASTM D1322-19 standard does not teach a formula for applying correction based on pressure changes.

[0054] Therefore, the inventors investigated the effect of pressure on smoke point results (and only pressure, while keeping other possible influences constant). From this study, the inventors derived a pressure correction formula based on pressure correction measurements using a pressure correction factor fp. The pressure correction formula using the pressure correction factor fp can be determined empirically from the data. Potentially, the pressure correction formula using the pressure correction factor fp can be determined theoretically. This pressure correction formula is not taught or recommended by the conventional ASTM D1322-19 standard method. It differs from the implicit pressure correction of the conventional ASTM D1322-19 standard. The conventional ASTM D1322-19 standard may not properly account for pressure because it does not account for humidity variations. The conventional ASTM D1322-19 standard requires recalibration every time the pressure change exceeds 0.7 kPa, and even when recalibration occurs, it does not account for humidity variations.

[0055] The present invention can apply its pressure calibration in different ways as described in this specification. The smoke point measurement can be normalized to 1013 hPa (1 atm) or another suitable pressure for normalization. Such normalization at 1013 hPa is not necessary, but is beneficial for comparing results. Therefore, preferably, the present invention applies its pressure calibration and records the normalization calibration at 1013 hPa, by calibrating these three measurements (method 1, described in more detail elsewhere in this specification) and then averaging them, or (method 2, described in more detail elsewhere in this specification) performing these three measurements according to the pressure and by calibrating the average value without calibration. The present invention can then calibrate the test results according to the pressure, either by calibrating the measured values ​​(for 1013 hPa) and applying the calibration corresponding to Method 1 already stored at 1013 hPa, or by not calibrating the measured values ​​according to the pressure and recalculating the calibration value from 1013 hPa during the test corresponding to Method 2.

[0056] As a result, the present invention performs an initial calibration of the equipment to calculate a correction factor f (also known as the lamp factor) according to paragraph 10 of ASTM D1322-19. This correction factor f corrects only for inherent errors in the camera, such as camera, lens, or device-specific setup malfunctions. Therefore, the operator of the equipment or method of the present invention will maintain these calibrations and also maintain compliance with the standard. The calibration and lamp factor system described in the standard is not pressure-dependent correction, but rather an application of smoke point measurements of each device-specific deviation (regardless of cause) observed during measurements at pressures close to a reference mixture. During this initial calibration, the operator should be aware of ambient humidity, temperature, and pressure.

[0057] Therefore, the present invention provides a testing apparatus and method for determining the smoke point of hydrocarbons. The apparatus includes: a device for determining the smoke point conforming to the specifications of ASTM D1322-19.

[0058] An imaging device for acquiring a series of digital images of a flame;

[0059] An ambient relative humidity sensor used to measure relative humidity;

[0060] An ambient temperature sensor used for measuring temperature;

[0061] A computer system linked to an imaging device, a humidity sensor, and a temperature sensor is programmed to analyze digital images from the imaging device to measure flame height, calculate absolute humidity using temperature and relative humidity measured by the temperature and humidity sensors, and correct the measured flame height based on the difference between the calculated absolute humidity and normalized absolute humidity, preferably based on the difference between the pressure during flame height measurement and normalized pressure. Typically, the normalized absolute humidity value is 0 gr / m 3 Up to 40gr / m 3 The value within the range is preferably 7gr / m 3 Typically, the normalized pressure value is between 800 and 1100 hPa, preferably 1013 hPa.

[0062] The present invention also provides a test apparatus for determining the smoke point of hydrocarbons by pressure correction, comprising:

[0063] Equipment for determining smoke point that conforms to the specifications of ASTM D1322-19.

[0064] A device for acquiring a series of digital images of a flame;

[0065] An environmental pressure sensor used to measure ambient pressure;

[0066] The invention includes a device linked to a series of digital images of a flame and a computer system linked to an ambient pressure sensor. The computer system is programmed to analyze the digital images acquired by the device to measure the flame height and, based on the ambient pressure measured by the ambient pressure sensor, to correct the measured flame point value of the hydrocarbon using the pressure measured by the pressure sensor, according to the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized ambient pressure. The invention also provides a method for determining the smoke point of a hydrocarbon using a testing device based on pressure correction. Attached Figure Description

[0067] The following figures are included to illustrate certain aspects of this disclosure and should not be considered as exclusive embodiments. The disclosed subject matter is capable of considerable modifications, alterations, combinations, and equivalents in form and function without departing from the scope of this disclosure.

[0068] Figure 1 This is a perspective view of an example of a manual smoke point testing device in the prior art.

[0069] Figure 2 This is a schematic diagram of an example of an automatic smoke point testing device according to the present invention, which automatically corrects the measured smoke point value according to atmospheric conditions.

[0070] Figure 2A This is a diagram of a computer.

[0071] Figure 3 An example of a typical flame appearance is shown.

[0072] Figure 4A -C shows Figure 2 An exemplary configuration of an automated smoke point testing device.

[0073] Figure 5A It is a humidity-based correction factor f h A graph relative to absolute humidity.

[0074] Figures 5B-5C It is used to derive the humidity-based correction factor f. h Exemplary smoke point measurements; these graphs are examples of several measurements (represented by points) at different absolute humidity levels, plotted respectively on... Figure 5B and 5C The lines in the diagram are trend curves calculated by Excel and used to illustrate the linearity of the effect; therefore, these lines are not the humidity correction factor f discussed elsewhere in the manual. h .

[0075] Figure 6 It is a curve of the correction factor relative to atmospheric pressure.

[0076] Figure 7A An exemplary calibration measurement is shown according to this disclosure using pressure correction method 1, which can be incorporated into a smoke point test method.

[0077] Figure 7B An exemplary test measurement using pressure correction method 1 is shown.

[0078] Figure 8A An exemplary calibration measurement is shown according to this disclosure using pressure correction method 2, which can be incorporated into a smoke point test method.

[0079] Figure 8B An exemplary test measurement using pressure correction method 2 is shown. Detailed Implementation

[0080] This disclosure relates to a device for measuring the smoke point of hydrocarbons, and more specifically, to a device and method for automatically correcting smoke point measurements based on atmospheric conditions.

[0081] The invention described herein relates to apparatus and methods for automatically correcting smoke point measurements based on atmospheric conditions or parameters (e.g., atmospheric pressure, ambient temperature, and / or air humidity). The test apparatus includes a humidity sensor and an ambient temperature sensor that measure atmospheric conditions (i.e., humidity and temperature), and these measurements (data) can be used to correct flame height measurements. Therefore, the invention typically corrects smoke point values ​​(flame height, mm) measured in existing calibrations based on the difference between the current atmospheric humidity (converted to absolute humidity) measured by the integrated humidity sensor of the test apparatus and a normalized absolute humidity standard value. Preferably, the invention also corrects smoke point values ​​(flame height, mm) measured in existing calibrations based on the difference between the current atmospheric pressure measured by a pressure sensor (preferably the integrated pressure sensor of the test apparatus) and the pressure recorded during calibration. Pressure measurements can also be used for real-time correction of flame height measurements and normalize smoke point measurements at a typical 101.3 kPa (1 atm, 1013 hPa). Preferably, the selected normalized pressure value is 1013 hPa, but it can be selected as any value between 800 and 1100 hPa.

[0082] The standard test method for the smoke point of kerosene and aviation turbine fuels is described in ASTM D1322-19, Standard Test Method for the Smoke Point of Kerosene and Aviation Turbine Fuels, ASTM International (April 2018) or its equivalent (collectively, the “Test Method”). The test method typically involves burning a fuel sample in a test apparatus and then measuring the maximum height of the resulting flame, which can be achieved with the fuel sample without smoke. The test apparatus typically includes a sealed wick supply lamp calibrated for pure hydrocarbon mixtures with known smoke points. The test equipment can be manual or automated, and the Test Method specifies the procedures for using such equipment.

[0083] More specifically, the test method includes the following steps: (i) preparing the test apparatus as described in Section 9 of ASTM D1322-19 Test Method; (ii) calibrating the test apparatus as described in Section 10 of ASTM D1322-19 Test Method; (iii) testing the fuel sample according to the procedure described in Section 11 of ASTM D1322-19 Test Method; and (iv) calculating the smoke point as described in Section 12 of ASTM D1322-19 Test Method; and (v) reporting the results as described in Section 13 of ASTM D1322-19 Test Method. As mentioned above, the specific procedures for the foregoing steps may depend on whether the test equipment is a manual or automated test equipment.

[0084] Figure 1 An exemplary conventional manual smoke point test apparatus 100 for testing fuel samples is shown in accordance with Section 11 of ASTM D1322-19 test method.

[0085] Reference Figure 1 The conventional (manual smoke point) testing device 100 includes a channel 102 and a candle 104 movable within the channel 102. The candle 104 includes a container filled with a fuel sample (i.e., a test sample) and supports a wick W that is immersed in the test sample when dipped into the container of the candle 104 (see [link to relevant documentation]). Figure 2 Candle 104 is movable, and a fuel-soaked wick is positioned in channel 102, where it is ignited for smoke point testing. A flame is thus generated within channel 102, and a scale 106 for measuring flame height is provided within channel 102, as shown. Furthermore, a chimney 108 can be provided on channel 102 to exhaust the generated combustion gases and smoke. Candle 104 is introduced into channel 102 before being ignited. Candle socket 110 is provided on channel 102 to receive and support candle 104. A wick guide 112, in fluid communication with candle socket 110, is provided within channel 102 to guide and introduce the wick W into channel 102. The position of candle 104 can be vertically positioned within candle socket 110, thereby controlling or changing the amount of wick W extending from wick guide 112, and thus controlling or changing the amount of wick W exposed to be ignited within channel 102 during the test method. By adjusting the length of the wick W extending from the wick guide 112, the size of the flame can be controlled as needed when the test method is performed.

[0086] When using the (manual smoke point) testing device 100, the flame height L of the test sample at the smoke point is visually read (measured) using the scale 106. n And the flame height L was measured according to Section 11.5 of ASTM D1322-19 test method. n Three such observations (i.e., L) 1 L2 L 3 The average smoke point readings are then averaged together to calculate the average reading "L". The corrected smoke point is then calculated by multiplying the average smoke point reading by a correction factor "f" (sometimes called the lamp factor).

[0087] Figure 2 This is a schematic diagram of an automatic smoke point testing apparatus 200 (hereinafter, testing apparatus 200) according to the present invention, which is configured to automatically correct the measured smoke point value according to atmospheric conditions. Testing apparatus 200 can be used to test fuel samples according to the procedure in Section 11 of ASTM D1322-19 test method (i.e., performing step iii).

[0088] The testing apparatus 200 includes a digital camera 202 and a computer 204. For example... Figure 2A As shown, computer 204 includes a microprocessor 222, memory 224, one or more data / signal inputs 226 for receiving signals from sensors 212, 214, 216 and digital camera 202, and one or more data / signal outputs 228 for reporting corrected smoke points of hydrocarbons or controlling candle shifting system 206. Digital camera 202 may include a photoelectric detection charge-coupled device (CCD), complementary metal-oxide-semiconductor (CMOS) image sensor, or other imaging sensor, preferably covering wavelengths from the ultraviolet to the infrared range. Optionally, digital camera 202 has zoom. However, digital camera 202 can be configured differently. During the testing method, the wick W of candle 104 is wetted with a fuel sample and then ignited over a flame to produce a flame F. Digital camera 202 is positioned and properly aligned relative to channel 102 such that it can capture (record) an image (or video) of the flame F burning from wick guide 112 upwards. Digital camera 202 is linked to computer 204, which has software for analyzing images received from digital camera 202 to determine (measure) and record the height of flame F. Additionally, test equipment 200 includes software for adjusting the height of flame F ("L"). n The candle shifting system 206 can be a motorized conveyor system for raising the candle 104 higher within the channel 102, thereby increasing (or decreasing) the amount of wick W extending from the wick guide 112, which has the effect of increasing (or decreasing) the size (height) of the flame F. The shifting system 206 can vertically translate the candle 104 as indicated by the directional arrow V to control the amount of wick W exposed within the channel 102 for combustion. In the example shown, the candle 104 is shown with no flame F on the wick W when it is below (outside) the wick guide 112, and with a height L on the wick W within the channel 102 when it is inside the wick guide 112. n Flame F.

[0089] The test equipment 200 may also include an infrared-resistant filter (not shown) placed between the flame F and the digital camera 202 for acquiring a series of digital images.

[0090] The testing equipment 200 is configured to automatically calibrate the measured smoke point value based on atmospheric conditions, including humidity, temperature, and typically pressure. (See again...) Figure 2 The test apparatus 200 shown includes a relative humidity sensor 212 for measuring relative atmospheric humidity, a temperature sensor 214 for measuring ambient temperature, and a pressure sensor 216 for measuring ambient atmospheric pressure during or simultaneously with flame height measurement, for example, on the day of digital image acquisition or within one hour before or after digital image acquisition. Furthermore, the relative humidity sensor 212, temperature sensor 214, and pressure sensor 216 communicate with a computer 204 (e.g., via wires or through one or more various wireless communication protocols). Therefore, the computer 204 can receive data indicating the current relative atmospheric humidity (via humidity sensor 212), the current ambient temperature (via temperature sensor 214), and the current atmospheric pressure (via pressure sensor 216). Figure 2 A humidity sensor 212, a temperature sensor 214, and a pressure sensor 216 are shown integrated within the test apparatus 200 and linked to the computer 204. However, it is not necessary for any one or more of the relative humidity sensor 212, temperature sensor 214, and pressure sensor 216 to be integrated within the test apparatus 200. However, the use of an integrated pressure sensor will prevent the test operator from entering incorrect (though convenient) pressure data. Even without the automatic pressure correction of this invention, the use of an integrated pressure sensor will ensure that the test operator performs a new calibration under pressure if a corresponding calibration value does not exist. The humidity sensor 212 and temperature sensor 214 can be used to compensate for the effect of humidity on the resulting smoke point measurement.

[0091] Humidity sensor 212, temperature sensor 214, and pressure sensor 216 can all be provided as separate components. However, one or more of humidity sensor 212, temperature sensor 214, and / or pressure sensor 216 can be integrated and combined as a separate component. For example, humidity sensor 212 and temperature sensor 214 can be integrated together and provided as a separate component. In other examples, temperature sensor 214 and pressure sensor 216 can be integrated together and provided as a separate component. Integrating temperature sensor 214 with humidity sensor 212 and / or pressure sensor 216 allows for compensation of internal thermal drift.

[0092] The pressure sensor 216 does not need to be integrated into the test equipment 400 and linked to the computer 204. Instead, the test operator can use other devices for measuring atmospheric pressure, such as the optional atmospheric pressure acquisition system 208, and then manually input the atmospheric pressure into the computer 204, for example, via data input 210.

[0093] Computer 204 includes software for automatically correcting drift in smoke point measurement results, which may be caused by temperature, humidity, and optional other atmospheric parameters such as pressure. Computer 204 automatically corrects the measured smoke point results based on one or both of the following: (a) the difference between the relative humidity measured by humidity sensor 212 and the absolute humidity calculated from the ambient temperature measured by temperature sensor 214, and / or (b) the difference between the current atmospheric pressure measured by pressure sensor 216 and the normalized pressure value during or concurrent with the test.

[0094] Figures 4A-4C Exemplary configurations of test equipment 200 according to one or more embodiments of the present disclosure are also shown. In the illustrated embodiments, test equipment 200 includes a housing 402, a power supply 404, and electronic devices 406, the electronic devices 406 including a computer 204. Figure 2 The computer 204 has a microprocessor 222 for performing calculations based on measurements from sensors 212, 214, 216 of the device 200, and a memory 224. Figure 2A Because the power supply 404 and / or electronic device 406 can generate heat within the housing 402, the test equipment 200 may be provided with a ventilation device. For example, the test equipment 200 may include a fan 408 configured to generate an airflow 410 through the housing 402 from an inlet (or entrance) 412 to an outlet (or exit) 414. At the inlet (or entrance) 412, the airflow 410 is at ambient temperature and enters the housing 402. At the outlet 414, the airflow 410, having been heated within the test equipment 200, is discharged from the housing 402 as a heated airflow 419. Here, the inlet 412 is located on the chassis 416 on the lower side of the housing 402, and the fan is located on the rear wall 418 of the housing 402 to draw the airflow 410 into the housing 402 via the inlet 410, through the housing to the outlet 414, and at the outlet 414 to discharge the airflow 410. The test equipment 200 also has a display screen 420, such as a touch screen for inputting or receiving information or commands or displaying information (e.g., test results or other parameters).

[0095] One or more of the humidity sensor 212, temperature sensor 214, and / or pressure sensor 216 may be located near the air inlet 412. In the illustrated embodiment, all sensors 212, 214, and 216 are located within the housing 402, on the chassis 416, near the air inlet 412. In this way, the airflow 410 entering the housing 402 and interacting with the sensors 212, 214, and 216 is “fresh” air representing the actual air temperature outside the housing 402. Therefore, the sensor (i.e., temperature sensor 214) can analyze this “fresh” air at a temperature indicating the actual ambient air temperature, after which this “fresh” air is subsequently guided through the housing 402 to cool various internal components of the test equipment 200, such as the power supply 404 and / or electronics 406, which can heat the “fresh” air above the actual ambient air temperature. In addition, the air inlets 410 are positioned where they can capture air from below the test equipment 200, for example on the chassis 416 shown, so that they can measure the air temperature, which is most representative of the actual ambient air temperature of the air that will eventually burn in the lamp during the test method.

[0096] Figure 4B This shows that when candle 104 is in the first position, it is equipped with Figure 2 and 4A 200. Testing equipment for components. Figure 4C This illustrates the setting when candle 104 is in the second position inserted into test device 200. Figure 2 and 4A The component testing equipment 200. In order to use the testing equipment 200, candle 104 is removed from... Figure 4B The first position, as shown, away from the test device 200, is moved to a second position on the transmitter of the candle shifting system 206 of the test device 200, as... Figure 4C As shown. If necessary, type in all sample details and start the test, which will result in the automatic measurement of at least some current atmospheric parameters. For more details, please refer to the equipment manufacturer's instruction manual. The candle is automatically introduced into the lamp and undergoes the flame appearance sequence specified in Section 11.5 of ASTM D1322-19. This includes lighting candle 104. The candle is then automatically leveled so that the flame is approximately 10 mm high and the lamp burns for 5 minutes. After a 5-minute stabilization period, the candle automatically rises until a tail of smoke appears, then slowly lowers through the following flame appearance sequence. Long tip; smoke slightly visible; flame unstable and rapidly changing. Figure 3 The flame "F" is shown. Figure 3 In the diagram, flame "A" is too high, flame "B" is correct, flame "C" is too low, and "X" represents the bottom of the flame. For example... Figure 3 As shown in (Flame A), the tip is long and thin, with the sides of the tip concave upwards. (See image below.) Figure 3 As shown in (Flame B), the tip disappears just shortly after, leaving a very slight, blunt flame. A jagged, unstable, luminous flame is sometimes observed near the tip of a real flame; these should be ignored. Figure 3 (Flame C) shows a circular tip. Determine the height of flame B, closest to 0.5 mm in the manual method or closest to 0.1 mm in the automatic method. Record the observed height.

[0097] The software of device 200 analyzes flame images acquired by a digital camera. It automatically detects the flame shape corresponding to flame B according to section 11.5.3 of ASTM D1322-19, and similarly... Figure 3 As shown. It determines the height of flame B to be as close as 0.1 mm. The test device 400 records the observed height. The candle conveyor lowers candle 104, the flame automatically extinguishes, and the conveyor returns to its stationary position. Due to the flame height resolution of the digital camera, the flame height is recorded to the nearest 0.1 mm. The device makes three separate observations of the flame height at the smoke point by repeating the flame appearance sequence specified in Section 11.5 of ASTM D1322-19. If these values ​​vary within a range greater than 1.0 mm, the test device 400 should warn the test operator. Repeat the test with a new sample and another wick. Remove candle 104 from the conveyor, rinse with heptane, and purge with air to prepare for reuse.

[0098] Computer 204 uses data measured by humidity sensor 212, along with temperature data (e.g., from temperature sensor 214) and pressure sensor 216 or atmospheric pressure acquisition system 208, to automatically correct the measured smoke point results based on absolute humidity. Therefore, aspects of the present invention improve the repeatability of the testing method and the accuracy of the smoke point results by incorporating humidity as a factor in smoke point calculation.

[0099] Humidity is an atmospheric condition that indicates the number of water molecules in the air. Humidity disrupts the combustion of kerosene, and therefore adversely affects the smoke point. The density of water vapor in the air is called absolute humidity (“AH”), expressed in kg / m³. 3The amount of water vapor present in the air is expressed as a percentage of the amount required for saturation at the same temperature, called relative humidity (“RH”) and expressed as a percentage (%RH). AH can be calculated based on RH, ambient air temperature (“T”), and atmospheric pressure (“P”). Therefore, test equipment 200 may include a humidity sensor 212 for measuring RH, a temperature sensor 214 for measuring ambient air temperature T, and a pressure sensor 216 for measuring the current atmospheric pressure P, and computer 204 can then use these measurements to calculate AH (using the RH-to-AH conversion formula; the formula for converting RH to AH is known). Sample calculations of AH are given in the following section entitled “Sample Calculation - Relative Humidity to Absolute Humidity Conversion Formula”. Furthermore, when performing smoke point calculations, computer 204 can use these measurements to apply a humidity correction factor fh (i.e., AH-based correction) to correct the measured flame height based on the difference between the calculated absolute humidity and the normalized absolute humidity value.

[0100] It has been observed that atmospheric pressure has a very small effect on the calculation of AH (less than 0.1% for a change of 250 hPa).

[0101] It was also observed that the ambient air temperature T may have a significant impact on the resulting calculations. Therefore, the temperature sensor 214 can be appropriately positioned relative to the test equipment 200 (and its housing) such that the measured ambient air temperature T represents the actual air temperature of the environment in which the test method is being performed.

[0102] This invention allows the test equipment 200 to be recalibrated to a state where smoke test measurements will be performed under standard (normalized) humidity, wherein the normalized humidity value is 0 gr / m 3 Up to 40gr / m 3 The value within the range is preferably 7gr / m 3 .

[0103] In the example shown, test equipment 200 may utilize atmospheric pressure measurement, such as pressure sensor 216, or an optional external atmospheric pressure acquisition system 208 instead of pressure sensor 216. Pressure sensor 216 transmits ambient air pressure values ​​to computer 204 (or other control unit). External atmospheric pressure acquisition system 208 acquires (receives) the ambient pressure value. The operator then manually transmits (inputs or types) the ambient air pressure value from external atmospheric pressure acquisition system 208 to data input 210 of computer 204 (or other control unit). For example, atmospheric pressure acquisition system 208 may include an external (or separate) barometer for measuring ambient atmospheric pressure to obtain a measured atmospheric pressure value, but does not directly feed said measured air pressure value to computer 204. The test operator may manually input this measured air pressure value into data input 210 integrated with computer 204, so that computer 204 can use this measured air pressure value. Therefore, data input 210 may include a touchscreen, keyboard, dial pad, or other device through which the test operator can manually input data for use by computer 204.

[0104] According to a preferred aspect of the invention, computer 204 automatically performs pressure correction using a pressure correction factor "fp" to correct for the measured flame height. This automatic pressure correction avoids the need for recalibration as indicated by the ASTM D1322-19 standard when pressure changes exceed 0.7 kPa. Therefore, when calibration values ​​at the current pressure ±0.7 kPa are unavailable, for example, when calibration values ​​are not stored in a calibration database, the automatic pressure correction facilitates the testing method by not requiring the test operator to perform a new calibration.

[0105] Therefore, if the method or apparatus of the present invention uses the pressure correction according to the present invention, it is not necessary to select calibration at the pressure closest to the measurement.

[0106] However, if the user (operator) wishes to calibrate the same reference mixture multiple times and chooses to calibrate at the closest pressure, he or she can still choose to calibrate at the pressure closest to the measurement. This invention allows the test equipment 200 to be recalibrated to the standard correct atmospheric pressure, typically 101.3 kPa (1 atmosphere), for smoke testing measurements. The computer 204 can automatically calibrate the test equipment 200 to the standard correct atmospheric pressure, typically 101.3 kPa (1 atmosphere), using information input via pressure sensor 216 or data input 210. Therefore, the computer 204 or the pressure acquisition system 208 can be associated with a calibration database to select the correct calibration value when automatically calculating the correction factor (lamp factor "f"). The calibration database can be stored in the memory of the computer 204.

[0107] This disclosure may also provide an apparatus and method in which a computer 204 automatically calculates calibration data at the current atmospheric pressure measured by the pressure sensor 216 during the performed test using stored calibration values ​​normalized to 1013 hPa.

[0108] Smoke point testing, calculation, and correction for atmospheric conditions.

[0109] It can be seen that the smoke point value is the flame height L. n The measurement at its finest shape at the end is the height limit before the test sample burns and produces smoke. Figure 3 A flame F is shown, having a common flame base "X" and various exemplary flame variations extending from the flame base X. Specifically, Figure 3 The image shows a flame variation "A" with a long, thin tip that appears slightly concave on the sides. Figure 3 Flame variations “B” and “C” are also shown, where flame variation B includes a slightly blunt flame tip, while flame variation C has a rounded tip. Flame variation A, extending from the flame base X, is too high, while flame variation C is too low. Therefore, the test procedure instructs the test operator to determine when the flame F has a flame shape corresponding to flame variation B, and to record the closest observed height of 0.5 mm when using manual equipment 100.

[0110] When using test equipment 200, the software of computer 204 analyzes the image of flame F acquired by digital camera 202 and automatically detects when flame F has a flame shape corresponding to flame change B. Then, the automatic equipment 200 sets the height L of flame F. n Determine the value to be closest to 0.1 mm and record the height L. n The value. Digital camera 202 observes the flame F through a window, which may include a filter such as an anti-infrared filter located between the flame and the digital camera.

[0111] As stated above, the ASTM D1322-19 test procedure requires testing the flame height (L) at the smoke point by repeating the flame appearance sequence specified in Section 11.5 of the ASTM D1322-19 test procedure. 1 L 2 L 3 Perform three separate observations. Then average these observations or readings together to calculate the average reading "L".

[0112] According to ASTM D1322-19, the final smoke point is calculated (closest to 0.1 mm) by equation (2) from Section 12 of ASTM D1322-19, which is "Smoke Point = L x f". In the equation, "L" is equal to the flame height L. n The average of the three individual readings or observations, “L” is the correction factor (sometimes called the lamp factor). As described above, before performing the test procedure (step iii), the correction factor “f” is calculated according to section 10 of the ASTM D1322-19 test procedure (i.e., step ii).

[0113] However, in this invention, the smoke point is typically calculated (to the closest possible 0.1 mm) using a modified method of Equation (2) from ASTM D1322-19, but also corrected for humidity with a humidity correction factor fh and optionally for pressure with a pressure correction factor fp. The determination of the correction factor “f” to account for errors inherent to the camera used to measure the smoke point, such as camera or lens malfunction or device calibration for adjusting tolerances, is more accurate because it uses a smoke point value corrected for humidity and preferably also for pressure.

[0114] When using test equipment 200, digital camera 202, computer 204 with its associated software, and shifting system 106 work together to read and record three separate observations of the flame height at the smoke point according to section 11.6 of ASTM D1322-19 test method. Computer 204 automatically averages the flame height L. 1 L 2 L 3 The computer 204 calculates the average reading "L" from three readings or observations, and then calculates the smoke point by multiplying the average reading "L" by a correction factor "fh" as a humidity correction factor. The computer 204 may also optionally calculate "fp" as a pressure correction factor.

[0115] Then, according to Section 13 of the test method (i.e., step v), the result of the equation can be reported as the smoke point of the test sample and rounded to the nearest 0.1 mm.

[0116] Instead of calibrating the average measured flame height, the testing equipment 200 can calibrate the height of each observed flame based on the AH (absolute humidity) value. n As previously stated, the testing method instructs the operator to make three separate observations of the flame height at the smoke point, and it has been observed that an increase in AH (Ambient Height) correspondingly leads to a decrease in the smoke point value. Therefore, humidity correction can be applied in real time to correct each of the three observations of the flame height. Specifically, before calculating the average reading L, the computer 204 can adjust the flame height L. n Each observation is multiplied by a humidity correction.

[0117] Figure 5A This is a graph showing the humidity correction factor fh as a function of absolute humidity (AH) according to one or more embodiments of this disclosure. In the graph, the defined reference value is 7 gr / m³. 3 The absolute humidity was obtained at a value corresponding to 40.4% RH at 20°C. Here, curve 500 has been derived, specifying a particular value for the humidity correction factor fh based on a specific absolute humidity (AH) represented on the X-axis of the graph. (See figure...) Figure 5A As shown, the normalized value of AH is 7gr / m 3 At that time, the correction factor fh is 1. Computer 204 can store curve 500 (or one or more similar curves) in its memory, allowing it to identify a humidity correction factor fh corresponding to the actual humidity (AH) encountered during a specific period of use of the test equipment 200. This humidity correction factor fh can be calculated using data measured via one or more sensors. Computer 204 can then analyze each observed flame height L. n (that is, L) 1 L 2 L 3 Multiplying by a humidity correction factor fh, makes the three separate flame height observations L 1 L 2 L 3 Each of these will illustrate the effect of humidity on flame height (i.e., humidity-corrected flame height observation fh*L). 1 fh*L 2 fh*L 3 ), can be based on humidity fh*L 1 fh*L 2 fh*L 3 The three corrected flame height observations are averaged together to obtain the average reading L. Therefore, the average reading L can be obtained using the following equation (3):

[0118] L=(f h *L 1 +f h *L 2 +f h *L 3 ) / 3 (3)

[0119] Figure 5ACurve 500 is a humidity correction curve as a function of absolute humidity (AH). Curve 500 is established by performing various smoke point measurements under different humidity conditions, such as in a room or test environment suitable for regulated humidity and temperature. Various smoke point measurements are performed on the seven reference fuel mixtures (i.e., mixtures 1 to 7) specified in Section 7.4 and on several kerosene samples using the procedures outlined in Section 11. These different smoke point measurements allow the humidity correction factor fh to be derived from the absolute humidity (AH) and the measured flame height. Figure 5B and 5C These are graphs of data points, and lines drawn through those data points, used to illustrate test data from smoke point measurements performed on ASTM D1322-19 Mix 7 and kerosene (Kero ADS05). These graphs of the test data are used to establish a formula for a humidity correction factor fh based on absolute humidity (AH) and the measured flame height. These graphs are examples of several measurements (represented by points) at different absolute humidities. Figure 5B and 5C The curves are trend curves (tread lines) calculated by EXCEL and are used to show the linearity of the effect. These lines are not the correction factor fh. Using this and other experimental and test data, an empirical formula for calculating the humidity correction factor fh can be established. Specifically, the humidity correction factor fh can be calculated using the following equation (4):

[0120] f h =1+(H m *((AH*K a )–K b (4)

[0121] in:

[0122] Hm is the measured flame height.

[0123] AH is absolute humidity, and

[0124] fh is the humidity correction factor.

[0125] Empirical formulas are derived from a large number of measurements. Figure 5B and 5C (representing a portion thereof), where all correction points are plotted on an Excel chart, and then a line connecting these points is calculated, with Ka and Kb being constant values ​​describing the line (an a*x+b type equation), which can be obtained by applying linear regression or other suitable analysis to empirical data, for example in... Figure 5B and 5C In this context, the empirical data is obtained from experiments with reference materials where only the AH variation is observed.

[0126] The final smoke point result can then be obtained by multiplying the average reading L of the flame height, which has already been corrected for humidity, by the lamp factor f.

[0127] Method of correction based on pressure

[0128] Therefore, the ASTM D132-19 test procedure requires that the flame height (L) be measured at the smoke point by repeating the flame appearance sequence specified in Section 11.5 of the ASTM D132-19 test procedure. 1 L 2 L 3 Three separate observations were made. These observations or readings were then averaged together to calculate an average reading “L”. The average reading “L” was then multiplied by a correction factor “f” (lamp factor) to correct for ambient pressure and obtain the final smoke point.

[0129] As mentioned above, the flame height L recorded during calibration n Measurements can combine several deviations from various sources. These deviations may be caused by the testing equipment itself and / or other environmental factors. For example, a deviation might be caused by the flame height L. n The deviations are caused by errors in the measurement itself and potential defects in the optics of camera 202. In some cases, these deviations can be so small that they can be considered constant.

[0130] As mentioned above, atmospheric pressure is another atmospheric condition that affects smoke point measurements. In particular, the smoke point value decreases as atmospheric pressure increases.

[0131] As described above, operators typically perform an initial calibration to obtain the correction factor "f" from ASTM D1322-19. However, in a preferred aspect, the present invention employs a pressure correction factor "fp" to avoid the need for recalibration when the pressure difference between the initial calibration pressure and the current measurement pressure is greater than + / - 0.7 kPa (greater than or less than 0.7 kPa). ASTM D1322-19 records the pressure during calibration, both when calculating the lamp factor "f" and when performing the current measurement. If the pressure difference between the calibration pressure and the current measurement pressure is greater than + / - 0.7 kPa, then ASTM D1322-19 also requires recalibration.

[0132] Under the same pressure conditions (within ±0.7 kPa), the reference fuel mixtures (or mixtures) are measured according to the specifications in Section 7.4 and Table 1 of ASTM D1322-19 Test Method, and the correction factor “f” of the ASTM D132-19 Test Method is calculated. Table 1 of the ASTM D132-19 Test Method identifies seven different reference fuel mixtures (i.e., Mixture 1, Mixture 2, Mixture 3, Mixture 4, Mixture 5, Mixture 6, and Mixture 7), each comprising a different mixture of toluene and isooctane (in %V / V), and also provides the standard smoke point (at 101.3 kPa) for each of the seven different reference fuel mixtures. The test operator must select two reference fuel mixtures whose values ​​are expressed as (bracket equivalent) the values ​​measured on the fuel sample to be tested. The calibration values ​​of the seven different reference fuel mixtures can be incorporated into a calibration database stored in the memory of computer 204. However, as stated above, if the pressure variation exceeds 0.7 kPa (i.e., ±0.7 kPa) during manual testing (see Section 10.1), or if no calibration value within 0.7 kPa of atmospheric pressure is stored in the calibration database during automated testing (see Section 10.2.2), then the testing method requires a new calibration of the testing equipment.

[0133] For example, before performing a test method, the test operator records the atmospheric pressure and checks the calibration database for a calibration value associated with the recorded pressure or a calibration value within ±0.7 kPa. If a calibration value exists at the recorded pressure ±0.7 kPa, the test operator can perform the test method, and the automated equipment will select both calibration values, bracketing the smoke point of the test sample. However, if no calibration value exists in the calibration database for the seven blends (mixtures 1 to 7) at the recorded pressure ±0.7 kPa, the test method instructs the operator to perform a new calibration at the recorded pressure, which is time-consuming and inconvenient given the often busy schedules in laboratories. Therefore, a test operator facing an instruction to perform a new calibration will simply enter (use) the atmospheric pressure with the calibration value instead of using a value corresponding to the actual pressure, which again produces biased results.

[0134] The present invention also provides an apparatus and method that improves pressure compensation in ASTM D1322-19 by employing a humidity correction factor fh to provide additional correction for humidity. In this case, the lamp factor f is calculated from the flame height for humidity correction according to the equation flame height x fh. In this alternative, the test apparatus 200 of the present invention includes a pressure sensor 216 for measuring the current atmospheric pressure “P” in real time, and a computer 204 can then preferably use this measurement data to apply a pressure-based correction (i.e., a pressure-based correction “fp”) when performing smoke point calculations. Furthermore, although an initial calibration is performed according to ASTM D1322-19, this improved method avoids the need for recalibration (or previously performed and stored) to determine the correction factor “f” every time the pressure change exceeds ±0.7 kPa. Moreover, the correction factor “f” is more accurate because it uses smoke point values ​​corrected for both humidity and pressure, taking into account errors associated with the camera itself used to measure the smoke point (e.g., camera or lens malfunction or adjustment tolerances).

[0135] Pressure-based calibration "fp" can be applied in two different ways. Test equipment 200 can be configured to perform pressure-based calibration selected by the test operator.

[0136] In the first method, the test operator can select three observed flame heights L n Each measurement applies a pressure-based correction in real time, similar to the application of humidity-based correction described above. Therefore, the three flame height observations L... 1 L 2 L 3 Each of these values ​​can be multiplied by a pressure-based correction "fp", and then averaged together to obtain the average measurement L. Therefore, the average reading L with pressure correction can be obtained using the following equation (5):

[0137] L=(f p *L 1 +f p *L 2 +f p *L 3 ) / 3 (5)

[0138] The final smoke point result can then be obtained by multiplying the average reading L of the flame height, which has already been corrected for pressure, by the lamp factor f.

[0139] The first method of applying pressure-based correction involves real-time calibration of the flame height measurement in a manner similar to that used for humidity-based correction. Here, each flame height measurement is calibrated to obtain the height at a normalized pressure (e.g., 10¹³ hPa). Therefore, a reference value for that specific normalized pressure (e.g., 10¹³ hPa) is recorded using a mixture calibration. In this way, the calibration thus only includes inherent biases of the test equipment 200 (e.g., optical defects). Then, during normal testing of the kerosene sample, the flame height L... n It is also corrected in real time as a function of pressure, so the result is equivalent to a measurement at normalized pressure (e.g., 10¹³ hPa). Therefore, the correction calculation for the lamp factor "f" as described in the ASTM D1322-19 test method uses the calibration value at normalized pressure (e.g., 10¹³ hPa). Here, a single calibration set with seven mixtures can be used without any further steps.

[0140] Figure 6 This is a graph of a correction factor relative to atmospheric pressure according to one or more embodiments of the present disclosure, showing an atmospheric pressure correction factor "fp" as a function of atmospheric pressure (P) in hectopascals (hPa). In the graph, for a pressure of 1013 hPa, the atmospheric pressure correction factor is equal to 1, such that a reference value is defined at this pressure using standard testing methods. The graph shows a derived curve 600 that specifies a particular value of the pressure correction factor "fp" based on a specific atmospheric pressure (P) represented on the X-axis of the graph. Curve 600 (or a similar curve) can be stored in computer 204 such that computer 204 can identify a pressure-based correction factor "fp" corresponding to the actual pressure "P" encountered during a specific use of the testing equipment and measured via pressure sensor 216. The computer then multiplies the pressure-based correction factor "fp" by each observed flame height L. n This makes the three separate flame height observations (i.e., L) 1 L 2 L 3 Each of the three flame height observations (L) illustrates the effect of atmospheric pressure on flame height. Therefore, the three flame height observations L... 1 L 2 L 3 Each of these values ​​can be multiplied by a pressure-based correction "fp", and then averaged together to obtain the average measurement L. The average reading L can be obtained using the following equation (5):

[0141] L=(f p *L 1 +f p *L2 +f p *L 3 ) / 3 (5)

[0142] Subsequently, the average reading “L” is multiplied by the lamp factor “f” to obtain the final smoke point via the above equation (2). Similar to the development of the fh curve, such as... Figure 6 The curve of fp can be developed by applying linear regression or other suitable analysis to empirical data obtained from experiments using reference materials with only pressure variations.

[0143] Figure 7A and 7B An exemplary process is shown for applying humidity-based correction, pressure-based correction, and a first method for calibrating and testing lamp factors using pressure correction method 1. Figure 7A The calibration measurement using pressure correction method 1 is shown. This method involves one calibration for each reference mixture, totaling seven calibrations. Figure 7A The process is shown to typically include a calibration measurement with pressure correction method 1, which includes a first segment 702 in which a calibration measurement is performed (i.e., calibration measurement segment 702). This shows a first set of calibration steps 706, including measuring the flame height (e.g., at 985 hPa and AH of 12.5 g / m). 3 The measured flame height is then multiplied by a humidity correction factor fh to calculate the humidity-corrected flame height (e.g., equal to 7gr / m). 3 (AH measurement). This value is then multiplied by a pressure correction factor fp to calculate the humidity and pressure corrected flame height (e.g., at a pressure equal to 1013 hPa). In the example shown, calibration measurement segment 702 is performed for each of the seven reference fuel blends, resulting in seven calibrations. Therefore, calibration measurement segment 702 is performed seven times at separate times, once for each of the seven reference fuel blends. This involves measuring the flame height L. n The first set of calibration steps 706 was performed three times to obtain the flame height (L). 1 L 2 L 3 Three independent observations of the flame height L. In the example shown, the first set of calibration steps 706 also includes calibrating each measured flame height L. n Multiply by the humidity correction factor fH, and then multiply the resulting product by the pressure-based correction fp (i.e., L). n *f h *f p Therefore, the first set of calibration steps 706 produces three flame height measurements, each based on humidity and pressure corrections (i.e., humidity and pressure corrected flame height measurements: L). 1 *fh *fp; L 2 *f h *fp; L 3 *f h *f p The calibration measurement section 702 then includes calculating the average reading L from three humidity and pressure-corrected flame height measurements (i.e., L = [(L...]). 1 *f h *f p )+(L 2 *f h *f p )+(L 3 *f h *f p )] / 3). Then, the calibration measurement section 702 includes storing or preserving the calibration data in the memory of the computer 204 and / or in the calibration database.

[0144] Figure 7B A test measurement using pressure correction method 1, including the second segment 704, is shown, wherein the test measurement is performed or executed (i.e., test measurement segment 704). Thereafter, as... Figure 7B As shown, the test sample can be measured according to the test measurement section 704. The test measurement section 704 includes the section for observing the flame height (i.e., measuring the flame height L). n A set of test steps 708 associated with the first set of test steps 708 is performed three times to obtain the flame height (L). 1 L 2 L 3 Three independent observations of the flame height L. In the example shown, the group test step 708 also includes taking each measured flame height L. n Multiply by humidity correction factor f h Then the resulting product is multiplied by the pressure-based correction fp (i.e., L). n *f h *f p Therefore, the first set of test steps 708 produces three flame height measurements that have been corrected for humidity and pressure (i.e., humidity and pressure corrected flame height measurements: L). 1 *f h *f p L 2 *f h *f p L 3 *f h *f p The test measurement section 704 then includes calculating the average reading L from three humidity and pressure-corrected flame height measurements (i.e., L = [(L...]). 1 *f h *fp)+(L2 *f h *fp)+(L 3 *f h *fp)] / 3). Then, the test operator or computer 204 can select two calibrations that take into account (or are equally considered) the average reading L, and then use equation (1) to calculate the lamp correction factor using the two calibrations that take into account / are equally considered. After that, the test operator or computer 204 can calculate the final smoke point (i.e., smoke point = L*f) using equation (2), and then the final result of the smoke point can be stored in the memory of computer 204 and / or reported.

[0145] It should be noted that, although Figure 7A The process illustrated in -B is based on humidity and pressure correction, but in other examples, pressure-based correction can be used instead of humidity-based correction.

[0146] Alternatively, in the second method, the test operator may choose to apply a pressure-based correction to the calibration measurements at a normalized pressure value (e.g., 1013 hPa), such that the lamp factor correction factor "f" generated by the calibration measurements includes the pressure correction, rather than being applied to the flame height measurement. Thus, errors in the flame height measurement can be corrected during calibration to obtain a set of calibration values ​​for each of seven different reference fuel mixtures at a given pressure. Then, during normal testing of the test sample (e.g., kerosene), in the second case, instead of correcting the measured height based on pressure, the value recorded at 101.3 kPa is corrected based on the pressure value measured during testing to calculate the calibration value required to calculate the lamp factor.

[0147] Figure 8A and 8B An exemplary process of an optional second method is shown, which applies humidity-based correction, pressure-based correction, and calibration and test measurements of the lamp factor via pressure correction method 2. Figure 8A The calibration measurement using pressure correction method 2 is shown. This method involves one calibration for each reference mixture, totaling seven calibrations. Figure 8B The test measurement using pressure correction method 2 is shown. For example... Figure 8A As shown, the second method of applying pressure-based correction includes applying humidity-based correction f h The pressure-based correction fp is applied to the calibration value used to calculate the lamp correction factor "f". For example... Figure 8B As shown, this is then multiplied by the average reading "L" to obtain the final smoke point. Here, no pressure-based correction is applied to the individual flame height measurements L during testing and calibration. nInstead, a pressure-based correction fp is applied to the calibrated measurement average to obtain a value at a normalized pressure, such as 10¹³ hPa. Therefore, the method uses a stored calibration with values ​​at a normalized pressure (e.g., 10¹³ hPa). The test is performed at the current ambient pressure, and thus the smoke point is measured at that pressure. To calculate the lamp factor “f”, the calibration value must be within ±0.7 kPa of the current pressure. The system generates a calibration value at the necessary pressure (test pressure), based on the calibration recorded at 10¹³ hPa, and applies a correction corresponding to the pressure difference. Two calculated calibration values, taking into account (equally considered) the flame measurements of the test sample, are selected and used in equation (1) to calculate the lamp factor “f”, which can then be multiplied by the average reading L to produce the final smoke point, as described in equation (2), and the final result can then be reported.

[0148] Therefore, the second method of applying pressure-based correction is the same as the standard testing method, except that it uses the calculated calibrations normalized to storage and 1013 hPa, rather than calibrations specifically performed at the desired pressure, such as... Figure 8A exemplified in .

[0149] Specifically, the calibration value recorded at 1013 hPa is divided by a pressure correction factor corresponding to the pressure measured during the test to obtain the calibration value for the test pressure. Two calibration values ​​for the flame measurement of the test sample are selected and used as in the ASTM standard to calculate the lamp factor f via equation (1). For example, errors in the flame height measurement can be corrected during calibration to obtain a set of calibration values ​​for each of seven different reference fuel mixtures at a given pressure. Then, when the test method is performed on the test sample (e.g., kerosene), in the second method, the measured height L is... n It is not based on pressure correction (however, when measuring the height L) n Before averaging to obtain the average reading L, the height L can be measured. n Multiply by humidity correction factor f h The height L measured for humidity correction n Instead of calculating the lamp factor f, the calibration value is calculated by correcting the value recorded at 101.3 kPa as a function of the pressure value measured during the test.

[0150] Figure 8A An exemplary process is shown for calibration measurements using pressure calibration method 2, a second method for performing application-based pressure correction. As shown, the process typically includes a first segment 802 in which calibration measurements are performed (i.e., calibration measurement segment 802). Figure 8B The second segment 804 is shown, in which test measurements are performed or executed (i.e., test measurement segment 804).

[0151] exist Figure 8A In this process, calibration measurement segment 802 is performed for each of the seven reference fuel mixtures, thus performing seven calibrations. In other words, calibration measurement segment 802 is performed seven times at separate times, once for each of the seven reference fuel mixtures. Calibration measurement segment 802 includes a first set of calibration steps 806, which includes measuring flame height (e.g., at 1022 hPa and AH 8.1 g / m). 3 The first set of calibration steps 806 was performed three times to obtain the flame height (L). 1 L 2 L 3 Three independent observations. The first set of calibration steps 806 then includes the step of generating humidity-corrected flame height measurements, wherein each measured flame height is multiplied by a humidity correction factor f. h To calculate the humidity-corrected flame height (e.g., equal to 7gr / m) 3 AH measurement), based on humidity correction for each flame height measurement (L) 1 L 2 L 3 Here, for example, the first set of calibration steps 806 therefore includes taking the flame height L of each measurement. n Multiply by humidity correction factor f h (that is, L) n *f h This causes the first set of calibration steps 806 to generate three flame height measurements that have already been corrected for humidity (i.e., humidity-corrected flame height measurements: L). 1 *f h L 2 *f h L 3 *f h The calibration measurement section 802 then includes calculating the average reading L of the humidity-corrected flame height measurement (i.e., L = [(L...]). 1 *f h )+(L 2 *f h )+L 3 *f h )] / 3). Then, the calibration measurement section 802 includes storing or preserving the calibration data in the memory of the computer 204 and / or in the calibration database.

[0152] Figures 8A-8B The process illustrated here is based on humidity and pressure correction, but in other examples, pressure-based correction can be used instead of humidity-based correction.

[0153] After that, as Figure 8BAs shown, the test sample can be measured according to the test measurement section 804. The test measurement section 804 includes the means for observing the flame height (i.e., measuring the flame height L). n The first set of test steps 808 is associated with this, and the first set of test steps 808 is performed three times to obtain three separate observations of the flame height (L). 1 L 2 L 3 These three individual observations can be averaged together to obtain an average reading L. In the example shown, the first set of test steps 808 also includes averaging each measured flame height L. n Multiply by humidity correction factor f h (that is, L) n *f h Therefore, the first set of test steps 808 generates three flame height measurements that have already been corrected for humidity (i.e., humidity-corrected flame height measurements: L). 1 *f h L 2 *f h L 3 *f h The test measurement section 804 then includes calculating the average reading L from three humidity-corrected flame height measurements (i.e., L = [(L...]). 1 *f h )+(L 2 *f h )+(L 3 *f h ] / 3). Then, the test operator or computer 204 can use the calibration data recorded at normalized pressure (e.g., 1013 hPa) and the pressure-based correction to calculate the calibration data at ambient pressure (e.g., 996 hPa). Specifically, the calibration data is calculated during test measurement segment 804 by dividing the calibration data recorded during calibration measurement segment 802 by the pressure-based correction fp. Then, the test operator or computer 204 can choose to consider (or equally consider) two calibrations (three humidity-corrected flame height measurements) of the average reading L, and then use equation (1) to calculate the lamp correction factor "f" using the aforementioned two calibrations of the measured values. Thereafter, the test operator or computer 204 can calculate the final smoke point (i.e., smoke point = L*f) using equation (2), and then the final result of the smoke point can be stored in the memory of computer 204 and / or reported.

[0154] Therefore, under either of the above methods, it is no longer necessary to perform more than one calibration batch with seven different reference fuel mixtures, and the constraint of recalibrating each time the pressure change is greater than + / - 0.7 kPa is eliminated, which further simplifies and improves the performance of the test method.

[0155] Therefore, the disclosed systems and methods are well adapted to achieve the mentioned and inherent objects and advantages. The specific embodiments disclosed above are merely illustrative, as the teachings of the invention can be modified and practiced in different but equivalent ways, as will be apparent to those skilled in the art who benefit from the teachings herein. Furthermore, the details of the constructions or designs shown herein are not intended to limit the scope of the invention beyond those described in the following claims. Therefore, it will be apparent that the specific illustrative embodiments disclosed above can be changed, combined, or modified, and all such changes are considered to be within the scope of this disclosure. The systems and methods illustratively disclosed herein can be suitably practiced in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein.

[0156] Specific embodiments of the present invention

[0157] The following paragraphs present specific embodiments of the present invention.

[0158] Paragraph A. This invention provides a testing apparatus for determining the smoke point of hydrocarbons, comprising:

[0159] Equipment for determining smoke point that conforms to the specifications of ASTM D1322-19.

[0160] A device for acquiring a series of digital images of a flame;

[0161] An ambient relative humidity sensor used to measure relative humidity;

[0162] An ambient temperature sensor used for measuring temperature;

[0163] The system includes a device linked to a series of digital images of a flame, a humidity sensor, and a temperature sensor. The computer system is programmed to analyze the digital images acquired by the device to measure the flame height, calculate the absolute humidity using the temperature measured by the ambient temperature sensor combined with the relative humidity measured by the relative humidity sensor during the test, and correct the measured flame height based on the difference between the calculated absolute humidity and the normalized absolute humidity value.

[0164] The test apparatus for paragraph A may include any of the following modifications.

[0165] The testing apparatus of paragraph A may further include an ambient pressure sensor linked to the computer system, wherein the computer system corrects the measured flame point value of the hydrocarbon based on the difference between the current ambient pressure measured by the pressure sensor and a normalized pressure value during the test.

[0166] In the test setup of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor.

[0167] The testing apparatus of paragraph A may further include an ambient pressure sensor linked to the computer system, wherein the computer system calibrates the measured flame point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor.

[0168] In the test setup of paragraph A, the device used to acquire a series of digital images of the flame may include a digital camera.

[0169] The test apparatus of paragraph A may further include an infrared-resistant filter placed between the facility for determining the smoke point, which conforms to the specification of ASTM D1322-19, and the apparatus for acquiring the series of digital images.

[0170] In the test setup of section A, the normalized humidity value can be 0 gr / m 3 Up to 40gr / m 3 7gr / m 3 Values ​​within the range.

[0171] In the test equipment of paragraph A, the device used to acquire a series of digital images of the flame may include a digital camera;

[0172] The device for determining the smoke point conforms to the specifications of ASTM D1322-19, and the device includes: a candle for holding the wick; a scale against the candle to measure the flame height; a channel configured to acquire digital images of the flame and the scale; and a candle shifting system for adjusting the flame height from the wick of the candle.

[0173] The test apparatus for paragraph A may further include:

[0174] Power supply, and

[0175] The outer casing is used to contain:

[0176] The digital camera,

[0177] Ambient relative humidity sensor,

[0178] Ambient temperature sensor, and

[0179] The computer system is linked to a device for acquiring the series of digital images, wherein the computer system includes an electronic device with a microprocessor.

[0180] In the test apparatus of paragraph A, the test apparatus may include means for ventilation, an air inlet for allowing airflow into the housing of the test equipment, and an exhaust port for discharging airflow that has been heated inside the housing of the test equipment.

[0181] In the test setup of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, wherein the computer system corrects the measured height of the flame based on the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value.

[0182] In the test equipment of paragraph A, the device used to acquire a series of digital images of the flame may include a digital camera;

[0183] The equipment for determining smoke point, conforming to the ASTM D1322-19 standard, includes a candle for holding the wick, a scale for measuring the flame height, a channel configured to acquire digital images of the flame and the scale, and a candle shifting system for adjusting the height of the flame from the candle wick.

[0184] The normalized pressure value is between 800 and 1100 hPa, preferably 1013 hPa.

[0185] In the test setup of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, wherein the computer system corrects the measured height of the flame based on the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized previous ambient pressure recorded during calibration, based on the ambient pressure measured by the integrated ambient pressure sensor.

[0186] In the test setup of paragraph A, the ambient relative humidity sensor may be configured to also include a temperature sensor to measure temperature.

[0187] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, wherein the computer system corrects the measured height of the flame based on the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and the test apparatus further includes a housing having an air inlet and an exhaust outlet, wherein the ambient relative humidity sensor is disposed near the air inlet.

[0188] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, wherein the computer system corrects the measured height of the flame based on the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and the test apparatus further includes a housing having an air inlet and an exhaust outlet, wherein the ambient relative humidity sensor is disposed near the air inlet, and wherein the ambient relative humidity sensor is disposed on the chassis of the housing.

[0189] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, wherein the computer system corrects the measured height of the flame based on the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and the test apparatus further includes a housing having an air inlet and an exhaust outlet, wherein the ambient relative humidity sensor is disposed near the air inlet, wherein the ambient relative humidity sensor is disposed on the chassis of the housing, wherein the housing has an air inlet and an exhaust outlet, and wherein the ambient temperature sensor is disposed near the air inlet.

[0190] Paragraph B. The present invention also provides a method for determining the smoke point of a hydrocarbon fuel sample, comprising:

[0191] The ambient relative humidity is measured using an ambient relative humidity sensor.

[0192] Use an ambient temperature sensor to measure the ambient temperature.

[0193] Test fuel samples, the tests including:

[0194] Identify the specific appearance of a flame based on the location of the burner in the lamp among different flame appearances.

[0195] Read the height of the flame on the ruler.

[0196] A device for acquiring and storing digital images is used to acquire and store a series of digital images of a flame at sufficiently close intervals in order to detect changes in the flame shape by analyzing these digital images.

[0197] The height of the flame is measured at the moment of change in flame shape; this height is considered to be the smoke point of the measured hydrocarbon.

[0198] The measured flame height, measured ambient relative humidity, and measured ambient temperature are input into a computer system, which is linked to a device for acquiring and storing digital images, an ambient relative humidity sensor, and an ambient temperature sensor.

[0199] The computer system is linked to a device for acquiring a series of digital images of the flame, a humidity sensor, and a temperature sensor. The computer system analyzes the digital images acquired by the device for acquiring the series of digital images to measure the flame height, and during testing, calculates the absolute humidity using the temperature measured by the ambient temperature sensor combined with the relative humidity measured by the relative humidity sensor. The measured flame height is then corrected based on the difference between the calculated absolute humidity and the normalized absolute humidity value to calculate the corrected smoke point; and

[0200] The report corrects the smoke point.

[0201] The approach in paragraph B may include any of the following modifications.

[0202] The method in paragraph B can determine the smoke point in accordance with the specifications of ASTM D1322-19.

[0203] The method in paragraph B may further include measuring ambient pressure using an ambient pressure sensor linked to the computer system, wherein the computer system corrects the measured flame point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor, according to the difference between the current ambient pressure measured by the pressure sensor during the test and a normalized ambient pressure value.

[0204] The method in paragraph B, wherein automatic correction of the measured smoke point may include correcting a calibration value during the calibration of the test equipment based on the difference between the current atmospheric pressure measured by the integrated pressure sensor and a normalized standard value, preferably, the normalized standard value of the pressure is between 800 hPa and 1100 hPa, most preferably 1013 hPa.

[0205] The method in paragraph B, wherein the apparatus for acquiring and storing digital images may include a digital camera, and wherein automatic correction of the measured smoke point may include normalizing a real-time flame point measurement performed by the digital camera to a standard pressure.

[0206] The method in paragraph B, wherein the apparatus for acquiring and storing digital images may include a digital camera, and wherein automatic correction of the measured smoke point may include normalizing a real-time flame point measurement performed by the digital camera to a standard pressure, wherein the normalized standard pressure value is 101.3 kPa.

[0207] The method in paragraph B may further include an integrated ambient pressure sensor linked to the computer system, wherein the computer system corrects the measured flame height based on the difference between the current ambient pressure measured by the pressure sensor during testing and the previous ambient pressure recorded during calibration, according to the ambient pressure measured by the integrated ambient pressure sensor.

[0208] The method in paragraph B, wherein the image acquisition interval can be between 0.1 seconds and 2.0 seconds.

[0209] The method in paragraph B, wherein the image acquisition interval can be between 0.5 seconds and 1 second.

[0210] The method in paragraph B, in which the detection of changes in flame shape is achieved by measuring a sudden change in the rate of decrease of the Freret diameter in the flame image.

[0211] The method in paragraph B, wherein the detection of changes in flame shape can be achieved by measuring a sudden change in the rate of decrease of the Ferrette diameter in a flame image, wherein, in order to detect a sudden change in the rate of decrease of the Ferrette diameter, the Ferrette diameter is measured at an angle α of less than 45°.

[0212] The method in paragraph B, in which the detection of changes in flame shape is achieved by measuring a sudden change in the rate of decrease of the Ferete diameter of the flame image, wherein the height of the flame is equal to the Ferete diameter of the flame image at α = 0°.

[0213] The method in paragraph B, wherein the detection of flame shape changes is achieved by measuring a sudden change in the rate of decrease of the Ferrette diameter of a flame image, wherein the digital image corresponding to the sudden change in the rate of decrease of the Ferrette diameter is subjected to a thresholding operation (also known as a binarization operation), wherein the thresholding involves, by means of one or more standard fuel mixtures (toluene / 2,2,4-trimethylpentane) having a known smoke point, setting all pixels with gray levels less than the determined threshold to zero, and setting all pixels with values ​​greater than the threshold to 1 (ASTM D1322-19). The threshold for the absolute flame height resulting in the measured smoke point of the tested fuel is determined using one or more standard fuel mixtures (toluene / 2,2,4-trimethylpropane), for which the smoke point is indicated by the ASTM D1322-19 standard.

[0214] The method in paragraph B, wherein the means for acquiring and storing digital images may include a charge-coupled device (CCD) digital camera, a complementary metal-oxide-semiconductor (CMOS) image sensor or other imaging sensor, preferably covering wavelengths from the ultraviolet to the infrared range.

[0215] The method in paragraph B, wherein the means for acquiring and storing digital images may include a charge-coupled device (CCD) digital camera, a complementary metal-oxide-semiconductor (CMOS) image sensor or other imaging sensor, preferably covering wavelengths from the ultraviolet to the infrared range, wherein an infrared-resistant filter may be placed between the flame and the means for acquiring and storing digital images.

[0216] The method in paragraph B, wherein the means for acquiring and storing digital images may include a charge-coupled device (CCD) digital camera, a complementary metal-oxide-semiconductor (CMOS) image sensor or other imaging sensor, preferably covering wavelengths from the ultraviolet to the infrared range, wherein the means for acquiring and storing digital images may store digital images having at least 256 gray levels.

[0217] The method in paragraph B, wherein the image acquisition interval may be between 0.5 seconds and 1 second, wherein the device for acquiring and storing digital images may be placed at a distance of approximately 10 cm to 15 cm from the lamp.

[0218] The method in paragraph B, wherein the image acquisition interval may be between 0.5 seconds and 1 second, wherein the device for acquiring and storing digital images may be placed at a distance of approximately 10 cm to 15 cm from the lamp, and wherein the device for acquiring and storing digital images is configured such that the stored digital images include images of all scales of the device for determining the smoke point.

[0219] The method in paragraph B, wherein the number of digital images in each series can be at least equal to 10.

[0220] The method of paragraph B, wherein the method may employ any test apparatus of paragraph A or any test apparatus of any paragraph having modifications of paragraph A.

[0221] Paragraph C. The present invention can also provide a testing apparatus for determining the smoke point of hydrocarbons, comprising:

[0222] Equipment for determining smoke point that conforms to the specifications of ASTM D1322-19.

[0223] A device for acquiring a series of digital images of a flame;

[0224] An environmental pressure sensor used to measure ambient pressure;

[0225] The device is linked to the series of digital images of the flame, and the computer system is linked to the ambient pressure sensor. The computer system is programmed to analyze the digital images acquired by the device to measure the flame height, and to correct the measured flame point value of the hydrocarbon using the pressure measured by the pressure sensor, based on the ambient pressure measured by the pressure sensor, the difference between the current ambient pressure measured by the pressure sensor during the test, and the normalized ambient pressure value.

[0226] In the test setup of paragraph C, the device for acquiring a series of digital images of the flame may include a digital camera;

[0227] The device for determining the smoke point conforms to the specifications of ASTM D1322-19, and includes: a candle for holding the wick; a scale against the candle to measure the flame height; a channel configured to acquire digital images of the flame and the scale; and a candle shifting system for adjusting the flame height from the wick of the candle.

[0228] The testing apparatus for paragraph C may further include:

[0229] Power supply, and

[0230] The outer casing is used to contain:

[0231] A device for acquiring a series of digital images of a flame, including a digital camera, an ambient pressure sensor, and...

[0232] The computer system is linked to a device for acquiring the series of digital images, wherein the computer system includes an electronic device with a microprocessor.

[0233] In the test apparatus of paragraph C, the test apparatus may include means for ventilation, an air inlet for allowing airflow into the housing of the test equipment, and an exhaust port for discharging airflow that has been heated inside the housing of the test equipment.

[0234] Paragraph D. The present invention may also provide a method for determining the smoke point of a hydrocarbon fuel sample, comprising:

[0235] Use an environmental pressure sensor to measure environmental pressure.

[0236] Test fuel samples, the tests including:

[0237] Identify the specific appearance of a flame based on the location of the burner in the lamp among different flame appearances.

[0238] Read the height of the flame on the ruler.

[0239] A device for acquiring and storing digital images is used to acquire and store a series of digital images of a flame at sufficiently close intervals in order to detect changes in the flame shape by analyzing these digital images.

[0240] The height of the flame is measured at the moment the flame shape changes; this height is considered to be the smoke point of the tested hydrocarbon.

[0241] The measured flame height and measured ambient pressure are input into a computer system, which is linked to a device for acquiring and storing digital images and an ambient pressure and temperature sensor.

[0242] The computer system automatically uses the ambient pressure measured by the ambient pressure sensor and corrects the measured height of the hydrocarbon flame value based on the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized ambient pressure, to calculate the corrected smoke point; and

[0243] The report corrects the smoke point.

[0244] The method in paragraph D can determine the smoke point in accordance with the specifications of ASTM D1322-19.

[0245] The method of paragraph D, wherein the method may employ any test apparatus of paragraph C, or any test apparatus of any paragraph having modifications of paragraph C.

[0246] The method in paragraph D, in which the detection of changes in flame shape can be achieved by measuring the sudden change in the rate of decrease of the Freret diameter in the flame image.

[0247] While compositions and methods are described as “comprising,” “containing,” or “including” various components or steps, they may also be described as “substantially composed of various components and steps” or “composed of various components and steps.” All figures and ranges disclosed above may vary in quantity. Whenever a numerical range with a lower and upper limit is disclosed, any numerical value falling within the stated range and any included range is specifically disclosed. In particular, each numerical range disclosed herein (in the form of “about a to about b,” or equivalently, “about a to b,” or equivalently, “about ab”) should be understood to describe each numerical value and range covered within a wider numerical range. Furthermore, terms in the claims have their ordinary, common meaning unless otherwise expressly and clearly defined by the patentee. Additionally, the indefinite articles “a” or “an” used in the claims are defined herein as referring to one or more elements introduced therein. If there is any conflict between the use of words or terms in this specification and in one or more patents or other documents incorporated herein by reference, the definitions consistent with this specification shall prevail.

[0248] The use of directional terms, such as up, down, above, below, upward, downward, left, right, etc., is relative to the illustrative embodiments depicted in the accompanying drawings, with the upward or upper direction pointing towards the top of the corresponding drawing and the downward or lower direction pointing towards the bottom of the corresponding drawing.

[0249] As used herein, the phrase "at least one" preceding a series of items, separated by the terms "and" or "or," modifies the list as a whole rather than each member of the list (i.e., each item). The phrase "at least one of" allows for the inclusion of at least one of any of the items, and / or at least one of any combination of items, and / or at least one of each item. For example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer only to A, only to B, or only to C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0250] Sample Calculation - Relative Humidity to Absolute Humidity Conversion Formula

[0251] 1. Water saturated vapor pressure

[0252] Between 16℃ and 30℃, the saturated vapor pressure of water can be approximated by the following formula:

[0253] svP = 4.528915 × T℃ 2 -35.685271 × T℃ + 1235.814887

[0254] in:

[0255] •svP: Saturated vapor pressure of water in Pascals (Pa)

[0256] •T℃: Temperature in degrees Celsius (°C)

[0257] 2. Partial vapor pressure

[0258]

[0259] in:

[0260] • PVP: Partial vapor pressure in Pascals (Pa)

[0261] • %RH: Relative humidity as a percentage (%)

[0262] 3. Dry air density

[0263]

[0264] in:

[0265] ·d dry air : in kg / m 3 Dry air density

[0266] ·P Atm Atmospheric pressure in Pascals (Pa)

[0267] ·M dry airThe molar mass of dry air, expressed in kg / mol, is 0.028965 kg / mol.

[0268] • R: Universal gas constant in J / (K·mol) = 8,3144621 J / (K·mol)

[0269] • T°K: Temperature in Kelvin (K)

[0270] 4. Absolute humidity

[0271]

[0272] in:

[0273] ·x: in kg water / kg dry air absolute humidity of the meter

[0274] • pvP: Partial vapor pressure in Pascals (Pa)

[0275] ·P Atm Atmospheric pressure in Pascals (Pa)

[0276] AH=x×d dry air

[0277] •AH: in kg water / m 3 air absolute humidity of the meter

[0278] ·x: with k geater / kg dry air absolute humidity of the meter

[0279] ·d day air : in kg / m 3 Dry air density

[0280] 5. General Conversion Formula

[0281]

[0282] in:

[0283] •AH: in kg water / m 3 air absolute humidity of the meter

[0284] •T℃: Temperature in degrees Celsius (°C)

[0285] • %RH: Relative humidity as a percentage (%)

[0286] ·d dry air : in kg / m 3Dry air density

[0287] ·P Atm Atmospheric pressure in Pascals (Pa)

[0288] ·M ary air The molar mass of dry air, expressed in kg / mol, is 0.028965 kg / mol.

[0289] • R: Universal gas constant in J / (K·mol) = 8,3144621 J / (K·mol)

[0290] • T°K: Temperature in Kelvin (K)

[0291] 6. Application

[0292] Testing laboratory environment:

[0293] • Relative humidity: RH = 40%

[0294] Temperature: T℃ = 22℃

[0295] Atmospheric pressure: P atm =1013hPa

[0296]

[0297] AH = 0.00784 kg / m 3 .

Claims

1. A method for determining the corrected smoke point of a hydrocarbon fuel sample, comprising: The ambient relative humidity value is measured using an ambient relative humidity sensor. Use an ambient temperature sensor to measure the ambient temperature value. The smoke point of the fuel sample was tested using equipment conforming to ASTM D1322-19 for determining smoke point. The test includes: An imaging device for acquiring and storing digital images acquires and stores a series of digital images of a flame at sufficiently close intervals. By analyzing these digital images, changes in flame shape are detected, and specific flame appearances are identified among different flame appearances according to the position of the burner in the lamp. The height of the flame is measured at the moment when the shape of the flame changes; this height is considered to be the measured smoke point of the tested hydrocarbon. The measured flame height, the measured ambient relative humidity value, and the measured ambient temperature value are input into a computer system linked to the imaging device, the ambient relative humidity sensor, and the ambient temperature sensor. The computer system calculates an absolute humidity value using a temperature value measured by an ambient temperature sensor and a relative humidity value measured by a relative humidity sensor. It then corrects the measured flame height based on the difference between the calculated absolute humidity value and a normalized absolute humidity value, to calculate the corrected smoke point. The normalized absolute humidity value is defined as 0 gr / m³. 3 Up to 40gr / m 3 Values ​​within the range; and Report the smoke point with humidity correction.

2. The method according to claim 1, wherein, The computer system is linked to an imaging device for acquiring a series of digital images of the flame, to a humidity sensor, and to an ambient temperature sensor. The computer system is programmed to acquire different appearances of the flame according to the position of the burner in the lamp by analyzing the digital images acquired by the imaging device for acquiring a series of digital images.

3. The method of claim 2, further comprising measuring an ambient pressure value using an ambient pressure sensor linked to the computer system, wherein the computer system is linked to the imaging device and an ambient relative humidity sensor, as well as an ambient temperature sensor and an ambient pressure sensor, to correct the measured humidity-corrected smoke point of the hydrocarbon based on the difference between a current ambient pressure value measured by the ambient pressure sensor during the test and a normalized pressure value, wherein the normalized pressure value is between 800 and 1100 hPa; and Report the smoke point with humidity and pressure correction.

4. The method according to claim 2, wherein, During the calibration of the test equipment, the corrections for ambient humidity and ambient pressure as described in claim 3 are applied to correct the calibration values ​​of the reference fuel mixture; and The calibration values ​​for humidity and pressure correction are stored in the computer system; as well as During testing of unknown hydrocarbon fuel samples, the same correction as described in claim 2 was applied to the measured flame height of the hydrocarbon fuel; and The measured flame height of the fuel is corrected for humidity and ambient pressure. A pair of calibration values ​​for humidity and ambient pressure correction are selected to take into account or equally account for the measured flame height value of the fuel. Based on the equation defined in ASTM D1322-19, the lamp factor is calculated using the two calibration values ​​mentioned above, taking into account or equivalently considering the measured values; and Multiply the measured flame height, corrected for humidity and ambient pressure, by the lamp factor; Report the moisture and pressure-corrected smoke point of hydrocarbon fuels.

5. The method according to claim 1, wherein, The normalized absolute humidity value is 7 gr / m 3 .

6. The method according to claim 3, wherein, The normalized pressure value is 1013 hPa.

7. A testing apparatus for determining the smoke point of hydrocarbons, comprising: Equipment for determining smoke point that conforms to the specifications of ASTM D1322-19. An imaging device for acquiring a series of digital images of a flame; An ambient relative humidity sensor used to measure relative humidity; An ambient temperature sensor for measuring temperature; and An imaging device linked to a series of digital images of a flame, a humidity sensor, and an ambient temperature sensor are connected to a computer system. The computer system is programmed to analyze the digital images acquired by the imaging device to measure the flame height, where the flame height is considered to be the measured smoke point of the tested hydrocarbon. An absolute humidity value is calculated using a temperature value measured by the ambient temperature sensor combined with a relative humidity value measured by the relative humidity sensor. The measured flame height is corrected based on the difference between the calculated absolute humidity value and a normalized absolute humidity value, where the normalized absolute humidity value is at 0 gr / m². 3 Up to 40gr / m 3 Values ​​within the range.

8. The testing apparatus of claim 7, further comprising an ambient pressure sensor linked to the computer system, wherein the computer system corrects the measured flame height of the hydrocarbon based on the difference between a current ambient pressure value measured by the ambient pressure sensor and a normalized pressure value during the test, wherein the normalized pressure value is between 800 and 1100 hPa.

9. The testing apparatus according to claim 7, wherein, The ambient temperature sensor is part of or separate from the ambient relative humidity sensor.

10. The testing apparatus according to claim 7, wherein, The device for acquiring a series of digital images of a flame includes a digital camera; The device for determining smoke point, conforming to the specification of ASTM D1322-19, includes: a candle for holding the wick; a scale against the candle to measure the flame height; a channel with a window through which a digital image of the flame and the scale is acquired; and a candle shifting system for adjusting the flame height from the wick of the candle.

11. The testing apparatus of claim 10, further comprising a housing having an air inlet and an exhaust outlet, wherein the ambient relative humidity sensor is disposed near the air inlet.

12. The testing apparatus according to claim 11, wherein, The ambient temperature sensor is located near the air inlet.

13. The testing apparatus according to claim 7, wherein, The normalized absolute humidity value is 7 gr / m 3 .

14. The testing apparatus according to claim 8, wherein, The normalized pressure value is 1013 hPa.

Images