Atmospheric distillation test apparatus and atmospheric distillation test method

Abstract

The present invention provides a system and method for distillation testing of liquid samples at atmospheric pressure with improved prediction of the heating required to reach the initial boiling point (IBP) and to ensure that the IBP is observed within specified time constraints and regardless of sample composition. The method involves monitoring the sample with a camera during different heating stages of the test to obtain visual images of the sample, and a computer analysing the observed image data to adjust the optimal distillation process.

Description

[Technical field]

[0001] The present invention provides an apparatus and method for distilling liquid fuel or petroleum samples at atmospheric (normal) pressure, and more particularly relates to an apparatus and method for the automated distillation of such samples at defined conditions. [Background technology]

[0002] Atmospheric distillation is a method of separating components with different volatility from a liquid mixture by heating and condensing the liquid sample. In general, the process involves heating a defined amount of sample in a flask to reach a vapor phase, then condensing the vapors in a thermostatically controlled tube and collecting the condensate in a receiver. The above test is carried out under certain conditions.

[0003] This atmospheric distillation method can be utilized to determine the boiling range properties of petroleum products and liquid fuels. Procedures have been established to test these properties. For example, the American Society of Testing and Materials (ASTM) has published a standard test method for testing the boiling range properties of petroleum products and liquid fuels, designated as ASTM D86-20b, Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure ASTM International, West Conshohocken, PA, 2020, www.astm.org. This is comparable to other global standards such as ISO3405, IP123, GOST2177, and JIS K2254.

[0004] Test apparatus have been developed for performing ASTM D86 and equivalent test procedures, both manually and automatically. These test apparatus generally include a round-bottom flask having a neck extending therefrom and a condenser connected to the neck of the flask. The opposite end of the condenser is connected to a receiving vessel or collection flask, and the condenser contains a cooling source, which generally may include a flowing liquid such as circulating water, but may also include a solid-state cooling device, such as a Peltier device or other equivalent thermoelectric cooler, around the condenser to maintain a temperature gradient therethrough. Heat is applied to the flask to begin the distillation process, and as the heat increases, the liquid sample begins to boil and vapors begin to rise to the neck of the flask. When the vapor reaches the cold condenser, it condenses into a liquid that rolls down the length of the condenser and is collected in a receiver.

[0005] In particular, these standardized distillation devices generally comprise a heating element, a distillation flask equipped with a thermometer making it possible to measure the temperature of the evaporated vapours and whose neck can be closed by a fluid-tight stopper which can be connected to a condenser, a collecting cylinder making it possible to collect the condensate and equipped with means for measuring the amount of condensate thus collected as a function of time, and control and regulating means making it possible to control and modify over time the operating variables of the heating element, in particular the temperature or power of this element, in order to obtain distillation parameters, in particular the distillation rate and / or the time for a specific volume according to a given standard.

[0006] The standards impose, inter alia, for a particular group of products, parameters such as the time elapsed from the start of heating the sample to obtaining the initial boiling point IBP, i.e. the time at which the first drop of condensate is observed in the collection cylinder, or the time elapsed from IBP to obtaining the 5% distillation point, i.e. the point at which 5% of the initial volume of the sample has been collected in the collection cylinder.

[0007] These standards also impose a distillation rate (i.e., the volume of evaporated sample or condensate per unit time during distillation) between the 5% distillation point and the point at which only 5 ml of sample remains in the distillation flask, or the time elapsed between the point at which only 5 ml of sample remains in the distillation flask and the final boiling point, FBP, i.e., the end of the distillation.

[0008] Automatic distillation devices currently commercially proposed and operating according to these standards implement a method according to the following: a given amount of sample to be analyzed (typically 100 ml) is introduced into the distillation flask, the distillation flask is positioned on the heating element, the distillation flask is closed and connected to a condenser, the sample to be analyzed is classified into groups defined by the selected standard, and the distillation of the sample to be analyzed is started, constantly measuring the amount of condensate collected in the collection cylinder, the temperature of the evaporated vapours and the operating variables of the heating element, in particular the temperature or power of this element. The values ​​thus measured are transmitted to control and regulating means, which then control the operating variables of the heating element to directly and automatically obtain the distillation parameters, in particular the distillation rate and / or time for a specific volume according to the selected standard. Automatic distillation therefore means that at least the heating is automatically controlled taking into account the measurements of the amount of condensate collected in the collection cylinder, the temperature of the evaporated vapours and the operating variables of the heating element, in particular the temperature or power of this element.

[0009] As stated, the ASTM D86-20b standard test method is available for measuring a number of specific characteristics and / or properties of petroleum product or liquid fuel samples as defined by this method. Such characteristics and / or properties include the initial boiling point ("IBP"), the 5% distillation point, and the point at which only 5 ml of sample remains in the distillation flask. The IBP is defined as the temperature reading observed at the moment the first drop of condensate falls from the bottom of the condenser. The 5% distillation point is the temperature reading at which 5% of the initial volume of the sample has been collected in the collection receiver.

[0010] An important and complex aspect of performing the ASTM atmospheric distillation test involves managing the heating of the flask to accurately measure the aforementioned characteristics and properties of various petroleum products, especially when the product composition changes due to changes in crude source, refining process, blending, or due to contamination. It is also difficult to find the right heating of the flask at the beginning of the test to respect the time between the initial boiling point and 5% recovery and to maintain a specific distillation rate in the future.

[0011] Initially, atmospheric distillation test procedures were performed manually. However, over time, automated test equipment was developed to facilitate testing and improve accuracy and repeatability. However, with some of these automated test equipment, the user must determine the initial power and duration to be applied, then a second power value to be applied thereafter until a uniform distillation rate (ml / mn) can be measured, and a heating adjustment is activated to maintain the correct rate. Rarely does the first test produce a value that meets the standard, and therefore the test must be repeated until a matching value is obtained.

[0012] U.S. Patent No. 8,372,247 (the '247 patent) discloses a prior art automated testing device in which the temperature of the liquid in the flask is measured by an external infrared ("IR") sensor. In particular, the distillation device of the '247 patent includes a distillation flask, a condenser connected to the distillation flask, a collection cylinder connected to the condenser to collect the distillate, a thermometer for indirectly measuring the temperature of the liquid sample present in the distillation flask, a thermometer for directly measuring the temperature of the vapor present in the distillation flask, and a heating element and a controller for controlling the heating. A single point measurement (i.e., the temperature of the liquid sample) is used to predict the initial heating of the unknown product. In the prior art, this prediction of the heating required to reach the IBP is made using a non-contact or external IR sensor to measure the temperature evolution of the liquid in the distillation flask. The prediction of the required heating before the 5% distillation point is based on the temperature of the liquid sample in the distillation flask and the temperature of the vapor at the point where the neck of the distillation flask connects to the condenser (measured by a standard vapor thermometer). However, these predictions are not always accurate. After the liquid sample begins to boil and vapor begins to rise in the flask, a dynamic temperature distribution appears in the neck of the distillation flask. Information regarding this vapor movement during this time delay or gap (i.e., between when the liquid just begins to boil and when the rising vapor column comes into direct contact with the standard vapor thermometer) is currently not measurable and is therefore unknown. However, if this data (e.g., the rate of column vapor movement, the vaporization energy of the sample) were ascertained, it could provide additional consideration in improving the heating adjustments, e.g., increasing or decreasing the heat, so that the IBP can be observed at an earlier time point. In other words, additional measurements made regarding the temperature distribution of the rising column of vapor would improve the predictability of the heating required prior to the IBP, and adjustments to the heating of the sample could be made earlier (i.e., before the vapor comes into contact with the standard vapor thermometer), thus ensuring that the IBP is observed within the time limits imposed by the selected standard. The test apparatus of the '247 patent also contributes to a high level of interference by various components (e.g., internal reflectance and emissivity).For example, there are high levels of radiation reflected from the inner walls of the collimator of the IR sensor monitoring the bulbous portion of the distillation flask. In addition, the base plate of the flask exhibits high emissivity, while the IR target area on the distillation flask exhibits low emissivity. These factors contribute to thermal interference and signal distortion, thus affecting the repeatability and accuracy of the test. Furthermore, to apply the necessary corrections to the heating regime so that the test procedure is performed under conditions that comply with the test standard, the test apparatus described in the '247 patent utilizes an algorithm based on a very large database that is inferred from the temperature of the liquid in the flask and the heating power initially applied. However, this results in tests that are correct the first time approximately 70-80% of the time.

[0013] U.S. Patent No. 10,363,495 (the '495 patent) is a potential improvement of the testing apparatus described in the '247 patent. The '495 patent discloses a prior art automated testing device in which the temperature of the liquid in the flask is measured by a first external IR sensor, and further includes a second infrared sensor to indirectly measure the temperature of the vapor just at the beginning of the glass column of the flask. However, this technique relies on data collected from a large number of tests performed over many years. As new types of samples evolve and are implemented, especially in biofuels, whose sources are increasingly evolving, such use of a database becomes less appropriate. Also, this technique analyzes the temperature rise of the product as a function of the power applied to the heating element to determine the specific heat of the sample and identify its type, and this calculation may be incomplete or erroneous since heat transfer may vary between the heating element and the flask (e.g., imperfect positioning of the flask on the support plate). The boiling temperature is also taken into account (by slowing the temperature rise) to help determine the type of sample being tested, but if boiling appears too late in the time slot allowed by the method, there is no longer the possibility to correct the heating quickly enough.

[0014] U.S. Patent No. 8,448,510 (the '510 patent) discloses yet another prior art automated testing device. The testing device of the '510 patent comprises an optical system capable of transmitting at least one infrared beam directed horizontally through a measuring cylinder and cooperating with a linear drive action via a step motor that can be moved vertically to allow the beam to be aligned with the meniscus of condensate collected in the cylinder so that the height of the meniscus can be detected. The optical system of the '510 patent comprises a dual optical barrier that is fixed to a frame and vertically translated / driven via a step motor and a fixed optical barrier. The dual optical barrier has two transmitter-receiver pairs each capable of transmitting a light beam directed horizontally through the measuring cylinder, one of the pair transmitting and receiving a central beam centered on the measuring cylinder to detect the bottom of the meniscus of condensate collected in the cylinder, and the second of the pair transmitting and receiving an off-center beam that is offset with respect to the central beam and passes between the center and the wall of the measuring cylinder to detect the bottom of the meniscus of condensate collected in the cylinder.

[0015] EP 1967268(A1) is directed to a collar for improving contact and communication between a side branch of a distillation flask and a condenser. EP 1967269(B1) is directed to a device for automatically positioning a heating element relative to a distillation flask.

[0016] European Patent No. 1967270(B1) is directed to a device for automatically aligning and positioning a distillation flask so that the flask is maintained in the proper orientation for performing the ASTM D86-20b test.

[0017] European Patent No. 1967848 (B1) is directed to a system for ensuring proper mounting of an insulating plate between a heating element and a distillation flask.

[0018] European Patent No. 1972378B1 is directed to a measurement test tube stand utilized in distillation testing incorporating a fluorocarbon resin based seal. However, these developments are generally unrelated to the measurement of the test sample in the flask during the test and therefore relate to test set-up rather than data capture during the test. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0019] Therefore, what is needed is an improved system and method for analyzing test samples in flasks when performing ASTM D86-20b testing.

[0020] The present invention provides a distillation testing device and method for automated distillation of liquid samples at atmospheric pressure, where a camera is installed to observe what is happening inside the distillation flask. The camera takes visual images. Therefore, the camera is not an IR sensor. [Means for solving the problem]

[0021] The invention controls the flask heating according to the analysis of the camera images in order to obtain the recorded time from the first application of heat to the initial boiling point according to the standard used, as well as the time from the initial boiling point time to 5% recovery according to the standard used, and the time from 5 ml residue to the end point according to the standard used.

[0022] Image analysis can also aid in controlling the uniform rate of distillation (ml / min) throughout the test.

[0023] Various phenomena and events during the early stages of the test when heat is applied can be analyzed and detected on the camera images as follows: The appearance of ripples in the liquid due to the presence of a hot liquid flow moving through the flask, The appearance of bubbles on the walls of the flask, Agitation of liquid surface, Increase in liquid level due to expansion, Rising and refluxing vapor columns due to condensation on the inside walls of the flask, and / or Reach of the vapor in the arm of the flask towards the condenser tube.

[0024] The present invention provides a test apparatus for distilling a liquid sample at atmospheric pressure, the test apparatus comprising: a flask having a round bottom, a neck portion and an opening at the top; A stopper for covering the top opening of the flask; a heating element in thermal communication with the flask base for heating the flask; A temperature sensor across the stopper; a condenser connected at one end to the flask; a cooling source surrounding the condenser; a receiver in communication with the condenser for receiving the distillate from the condenser; a sensor for monitoring the level and / or amount of distillate collected in the receiver during the distillation test; a camera positioned to monitor the behavior of the liquid sample in the flask during the distillation test to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; and an image analysis system for controlling the heating elements based on analysis of the image data.

[0025] The present invention also provides a method for automated distillation of liquid samples at atmospheric pressure using the test apparatus of the present invention, preferably regardless of composition, under conditions defined by standard test methods (e.g. ASTM D86-20b), The test equipment is a flask having a round bottom, a neck portion and an opening at the top; A stopper for covering the top opening of the flask; a heating element in thermal communication with the flask base for heating the flask; A temperature sensor across the stopper; a condenser connected at one end to the flask; a cooling source surrounding the condenser; a receiver in communication with the condenser for receiving the distillate; a sensor for monitoring the level and / or amount of distillate collected in the receiving vessel during the distillation test; a camera positioned to monitor the behavior of the liquid sample in the flask during the distillation test and to obtain image data of the liquid sample, preferably of the liquid sample and of vapor evaporated from the liquid sample; an image analysis system for analyzing the image data and for controlling the heating elements based on the analysis of the image data; The method is: selecting a group of products to be analyzed as liquid samples; adjusting the temperature of the condenser and the receiver; introducing a predetermined amount of liquid sample into an automated distillation assembly flask; initiating a test using a start trigger; heating a flask containing the liquid sample with a heating element; monitoring the behavior of the liquid sample in the flask during the distillation test using a camera to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; analyzing the image data in an image analysis system; detecting incipient boiling of the liquid sample using an image analysis system; measuring the temperature of the vapor in the flask with a temperature sensor; adjusting the heating by controlling the heating elements based on analysis of the image data; measuring a recovery of the distillate produced from the liquid sample and received in the receiver; and c. stopping the heating when the distillation endpoint is reached. [Brief description of the drawings]

[0026] The following figures are included to illustrate certain aspects of the present disclosure and should not be viewed as exclusive embodiments. The disclosed subject matter is capable of considerable modification, combinations, and equivalents in form and function without departing from the scope of the present disclosure. [Figure 1]FIG. 1 is a schematic diagram of an exemplary distillation test assembly according to one or more embodiments of the present disclosure. [Diagram 2] 1 illustrates an exemplary method according to the present disclosure. [Diagram 3] FIG. 13 shows an alternative schematic diagram of an exemplary distillation test assembly with two cameras according to the present disclosure. [Figure 4] 13 shows an exemplary shift in a vertical line that may be provided on a backlight and appears on the neck of a flask, according to the present disclosure. [Diagram 5] 2 illustrates an exemplary housing that can be used with the distillation test assembly of FIG. 1. [Figure 6] FIG. 5 shows an exemplary housing with a flask that can be used with the distillation test assembly of FIG. 1. [Figure 7] 6 illustrates another view of the exemplary housing of FIG. 5 with the movable panel in a lowered position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG. 1 illustrates an exemplary distillation assembly 10 according to one or more embodiments of the present disclosure. In the illustrated example, the distillation assembly 10 includes a distillation flask 12 having a stopper 18, a temperature measurement system, e.g., a thermometer 20, for measuring vapor temperature, a condenser 22, a cooling source 36, a receiver (also known as a receiving vessel, e.g., a collection flask or other receiving glassware) 24, a base plate 28 having an opening in which the distillation flask sits, a housing 30, and a heating element 26. In the illustrated example, the distillation flask 12 has a bulbous or lower rounded portion 14 configured to contain a liquid fuel sample 38 and a neck portion 16 extending upwardly from the lower rounded portion 14. The condenser 22 connects to the neck portion 16 of the distillation flask 12 using a flask side tube 23. The stopper 18 forms a seal at the top of the neck portion 16, thereby sealing the distillation flask 12 from the outside environment.

[0028] As shown, a stopper 18 is provided at the top end of the neck portion 16 and supports the thermometer 20 such that the thermometer 20 is suspended within the neck portion 16. The thermometer 20 extends through the stopper 18 via an opening (not shown) in the stopper 18 such that the tip 21 of the thermometer 20 is located within the neck portion 16 just below where the bypass 23 connects to the neck portion 16 of the distillation flask 12. The thermometer 20 is mounted through the stopper 18 to mechanically center the thermometer 20 within the neck 16 of the distillation flask 12 without steam leakage. Non-limiting examples of typical centering devices for mechanically centering the thermometer 20 within the neck 16 of the distillation flask 12 are shown in Figures 3 and 4 of ASTM D86-20b, which are incorporated herein by reference in their entirety. The thermometer 20 measures the temperature of vapor rising from the liquid sample 38 when the vapor directly contacts the tip 21 of the thermometer 20. A cooling source 36 surrounds the condenser 22. A receiver 24 collects the condensate or distillate 40 produced by the distillation process. The thermometer is typically a mercury in glass thermometer or an electronic temperature measurement system.

[0029] Typically, a barometer 70 is provided, which is a pressure measuring device capable of measuring the local station pressure at the site of its use, e.g., at the same elevation relative to sea level as the apparatus in a laboratory, to an accuracy of 0.1 kPa (1 mm Hg) or better. The barometer 70 is provided to determine the local atmospheric pressure at which the distillation assembly 10 is used.

[0030] The cooling source 36 may comprise various types of cooling devices, such as a device configured to provide a continuous flow of water or a solid-state cooling device. In the illustrated example, the cooling source surrounds the condenser 22 and creates a temperature gradient where accumulated vapor from the distillation flask 12 condenses and rolls down the condenser 22 until the condensate 40 drips into the receiver 24. The receiver 24 may be of various configurations, including cylindrical, and may be graduated to measure the amount of distillate 40 collected. In some embodiments, one or more sensors 25 may be utilized to determine the amount of distillate 40 collected in the receiver 24 during a distillation test. The amount of distillate may be by volume or weight. The temperature of the air surrounding the receiver 24 may be regulated.

[0031] In the illustrated example, the distillation assembly 10 is configured to observe the liquid sample 38 in the distillation flask 12 and to control the heating of the heating element 26 based on the observation of the liquid sample 38 by the camera 50. The camera 50 communicates wirelessly or via a wired connection (e.g., an Ethernet cable 54) with an image analysis system including a computer 52. The computer 52 may include control and adjustment means that allow the operating variables of the heating element, in particular the temperature or power of this element, to be controlled and changed over time. Thus, the heating element 26 may communicate with the computer 52 wirelessly or via a wired connection (e.g., an Ethernet cable or other type of cable 56). The computer 52 is configured with software that receives data from the camera 52 (i.e., images of the sample 38), analyzes and interprets such data, and then controls the heating element 26 based on the analyzed and interpreted image data to obtain distillation parameters, in particular the distillation rate and / or time for a specific volume according to a predetermined standard.

[0032] As can be seen in FIG. 1 , the computer 52 comprises a microprocessor 60, a memory storage device 62, one or more data / signal inputs 64 for receiving signals, for example, from the camera 50 (and / or other sensors (not shown)), and one or more data / signal outputs 66 for sending control signals, for example, to control the heating element 26 to regulate the heating of the sample 38. The camera 50 is connected to the computer 52, which has software for analysing the images received from the camera 50 to determine (measure) and record the sample during different stages of the test. The camera 50 observes the sample 38 in the flask throughout the test, for example, from the start of the test through the distillation of the sample 38. The computer 52 analyses what is happening to the sample 38 as the heating element 26 applies heat to the sample 38 during the test.

[0033] The power required at the beginning of the test is variable. For example, a few watts may be required if the test sample is gasoline, but up to several hundred watts may be required if the test sample is diesel. Thus, the test procedure may generally involve applying low power heating and then gradually increasing the heating until the appearance of a first phenomenon (ripples in the sample 38) detected by analyzing image data from the camera. Then, according to the time remaining to obtain the first droplet (IBP), the computer 52 may adjust the heating power to comply with the conditions required by the applicable standard.

[0034] Accordingly, computer 52 may also be configured to receive data indicative of the level / amount of condensate 40 in receiver 24. For example, computer 52 may be in communication with sensor 25 that monitors the level / amount of condensate 40 in receiver 24. After 5% recovery has been collected in receiver 24, the heating power of heating element 26 is managed by computer 52 to maintain a uniform distillation rate (ml / min), i.e., the rate at which the receiver is filling.

[0035] The computer 52 is programmed to analyze the image data collected by the camera 50 and can detect phenomena in the test sample 38 based on differences in successive images provided by the camera 50. The computer 52 can utilize some numerical filtering to reduce artifacts, and the area of ​​the image analyzed can be configured as a function of the observed phenomenon.

[0036] For example, computer 52 may identify the appearance of ripples in the liquid due to the presence of a hot liquid stream moving within the flask by detecting small differences in the sample by analyzing successive images, even though the successive images appear very similar due to the relative slowness of the phenomenon.

[0037] With regard to the appearance of gas bubbles on the wall of flask 12, computer 52 can detect the change between images when the first gas bubble appears, and then detect when the gas bubble remains stable over a period of time and how long the gas bubble subsequently remains "attached" to the wall of the flask before rising to the surface.

[0038] With respect to agitation of the liquid surface of the sample, computer 52 may detect changes between images centered on the upper area of ​​sample 38.

[0039] With regard to the increase in level due to expansion, the computer 52 may detect a gradual upward movement of the "stirring of the liquid surface" phenomenon as compared to previous images.

[0040] With regard to the rise of vapor and reflux due to condensation on the inner walls of the flask 12, the computer 52 may detect a change between images focused on the neck 16 area of ​​the flask 12. Also detected (and visually visible) while vapor is not visible is the reflux phenomenon, which generally occurs at the interface of the sample vapor and the air above. However, some samples with low boiling temperatures (e.g., gasoline or certain solvents) do not have this reflux phenomenon because the temperature of the flask 12 is not significantly lower than the temperature of the vapor, causing the vapor to condense on its walls. In these instances, the backlight 32 may be provided behind the flask 12, opposite the camera 50 (i.e., so that the flask 12 is between the camera 50 and the backlight), so that vapor detection may be performed via the computer 52 due to the vapor having a different refraction angle than air. When viewing the flask 12, a vertical line may appear and become visible at the edge of the neck 16 of the flask 12 (which is a glass tube) formed by the walls surrounding the flask. Additionally, one or more vertical lines (e.g., black vertical lines) may be provided on the backlight 32 such that one or more vertical lines are visible through the neck 16 of the flask 12 in addition to the vertical lines that appear at the edges of the neck 16 described above. When observed, these vertical lines (on the neck 16 and / or backlight 32) will appear to shift (or become misaligned) in the presence of sample vapor and will no longer be aligned with the lines of the "air" area above, and computer 52 may detect this change. Thus, computer 52 may utilize the change in refractive index of the medium to detect the vapor.

[0041] FIG. 4 shows an example of how computer 52 can analyze the image of camera 50 using refractive index, according to some examples. In the illustrated example, a pair of vertical lines 402, 404 appear at the edge of neck 16 of flask 12, and one or more additional vertical lines 406 may be positioned behind flask 12 (e.g., on backlight 32) to be seen through neck 16. During testing, a vapor zone 412 is created above the sample and below air zone 410. Air zone 410 and vapor zone 412 are separated by boundary 408 beyond which the vapor does not extend. When enough vapor is created to form vapor zone 412, vertical lines 402, 404, 406 shift laterally or become misaligned at boundary 408, as shown by misalignment 414. Stated differently, vertical lines 402, 404, 406 in air zone 410 are not aligned with vertical lines 402, 404, 406 in vapor zone 412. By identifying the progression of the mismatch 414, the current vapor level can be confirmed and detected, and the movement (up / down) of the vapor level can also be determined. This information can be used to detect the vapor / air boundary line in the flask neck 16 for samples with very low or no visible condensation reflux on the walls of the flask 12.

[0042] With respect to the arrival of vapor in arm 23 of flask 12 towards condenser tube 22 , computer 52 may detect a change between images in the area of ​​side arm 23 of flask 12 .

[0043] FIG. 1 shows an example in which a camera 50 is positioned to continuously monitor a liquid sample 38 .

[0044] However, as shown in FIG. 1, the camera 50 is typically positioned and oriented to focus on the entire flask 12 (i.e., the camera 50 is positioned to monitor the entire height of the flask 12, rather than being positioned very close to the sample such that a portion of the flask 12 is outside the field of view or observation window 80 of the camera 50) and continuously feeds its image data / information to the computer 52. Thus, the camera 50 may be equipped with a wide-angle lens and appropriately oriented to capture (record) an image (or video) of the entire flask 12. The entire flask includes the liquid sample 38 in the lower rounded portion 14 of the distillation flask 12 and the neck portion 16 of the flask 12 where the vapor is formed. In this way, the entire flask 12 can be within the field of view 31 of the camera 50. In the illustrated example of FIG. 1, the camera 50 is supported so as to be aligned with the window 31 of the housing 30. The housing 30 may be in the form of a chimney and may have the window 31 formed in one of its walls. Preferably, the camera 50 is positioned behind the window 31 in order to view the entire distillation flask 12 through the window 31. In this way, the camera 50 is protected from the heat radiated by the heating element 26 and / or from fire hazards that may occur during testing in the chimney.

[0045] The image analysis system of the test device can further detect abnormal situations during the distillation process, such as smoke formation in the flask or accidental flask breakage, and activate available safety measures such as an alarm.

[0046] Optionally, the test apparatus includes a fire detection and suppression system, and computer 52 determines whether a fire event is occurring in the chimney and activates a fire extinguisher in the chimney to extinguish the fire. The fire detection and suppression system may also include heat, temperature and / or smoke sensors (not shown) that communicate with computer 52 and transmit data so that computer 52 can determine whether a fire event is occurring in the chimney (housing 30).

[0047] Also, the backlight 32 described above may be provided within the housing 30, behind the flask 12, opposite the camera 50. As shown, the backlight 32 may be positioned behind the flask 12, such that the flask 12 is between the window 31 and the backlight 32, illuminating the flask 12 for monitoring by the camera 50. However, the backlight may be provided elsewhere within the housing 30 and / or additional backlights may be provided elsewhere within the housing 30 in addition to those shown in FIG.

[0048] Various types of cameras may be used. The camera 50 may be a digital camera with a light-detecting charge-coupled device (CCD). However, the camera 50 may be configured differently. In one example, the camera 50 is a camera with a complementary metal oxide semiconductor (CMOS) sensor, although other technologies may be used. In some examples, the camera 50 has a lens with a wide-angle lens and / or an infrared (IR) filter. In some examples, more than one camera may be used, including one or more additional cameras that focus on a particular aspect of the test apparatus, such as a portion of the distillation flask or on the sample, etc.

[0049] FIG. 3 shows an alternative schematic of an exemplary distillation test assembly as in FIG. 1, modified to have a second (additional) camera 51. The second camera 51 may communicate with the computer 52 wirelessly or via a wired connection (e.g., an Ethernet cable 55) to one or more data / signal inputs 64. The second camera 51 observes the flask neck 16 through a window 33. Both cameras 50, 51 may be oriented horizontally, as shown in FIG. 3, or both may be tilted at an angle to focus on a portion of the flask 12, or a combination thereof. In FIG. 3, the first camera 50 is tilted and the second camera 51 is horizontal. However, if desired, the second camera 51 may be tilted instead and / or the first camera 50 may be horizontal instead.

[0050] Thus, as described herein, the subject matter of the present disclosure works by observing the visual effects of heat applied to the sample 38, thereby mimicking a manual test run. This allows the first reaction of the sample 38 to the heat to be detected sooner than the IR sensor method, thus allowing the computer to adjust the heating sooner and avoid being caught out in the "too late" case, as can occur with the IR sensor system disclosed by U.S. Pat. No. 10,363,495 (the '495 patent). The subject matter of the present disclosure is less dependent on the quality of the heat exchange between the heating element 26 and the flask 12, since the important information to know is whether to increase or decrease the heating power. The camera 50 also allows the rise of the vapor in the neck 16 of the flask 12 to be tracked, which is not the case with devices equipped with IR sensors, such as the device described in the '495 patent.

[0051] The use of the camera and the analysis of the images is typically not based on any database: the system works by observing the visual effect of heating on the sample, just as an operator would (and sometimes still does) manually.

[0052] The computer 52 controls the heating element 26 according to an analysis of the images of the camera 50. The computer 52 is programmed to analyze the images of the sample 38 as the heating element 26 heats the sample 38. Such image analysis serves to regulate the distillation rate (i.e., ml / min) throughout the test. In particular, the computer 52 can analyze the images of the sample 38 observed by the camera 50 during different stages of the test for the appearance of ripples on the surface of the liquid sample 38 due to the presence of a hot liquid stream moving within the flask 12, the appearance of bubbles on the inner walls of the distillation flask 12, the stirring of the liquid surface of the sample 38 within the flask 12, the increase in the level of the sample 38 due to expansion, the rise of vapors and reflux due to condensation on the inner walls of the flask 12, and / or the arrival of vapors in the arms of the flask towards the condenser tube 22, etc. For example, during the test phase and after 5 ml of condensate have been collected in the receiver 24, the computer 52 may measure the distillation rate (i.e., the flow rate (ml / min) of condensate collected in the receiver 24) via the sensor 25, and based on this measurement, the computer 52 may control the heat output of the heating element 26 applied to the distillation flask 12 and the sample 38 therein in order to maintain the distillation seed within defined limits.

[0053] Many petroleum products such as gasoline, kerosene, diesel, etc. are mixtures of hydrocarbons, and they are not composed of a single chemical molecule, unlike products like pure acetone or toluene. For a mixture product, the vapor temperature rises as the distillation proceeds, with the "lightest" compounds evaporating at the beginning of the test and the "heaviest" compounds, which require more heat for evaporation, evaporating at the end of the test. Usually, compounds evaporate one after the other, resulting in a gradual rise in the temperature vs. % recovery curve. However, with the emergence of new compounds and biofuels, test operators are increasingly presented with samples that present a "hole" in the smooth progression of evaporation, due to a significant difference in the boiling points of two adjacent compounds. It happened when the "lightest" compound evaporated, but a significant increase in heating power is required to boil off the next compound. During this time, called the "hesitation point," there is no (or less) vapor production, and the rate of distillation slows. The operator or automated distillation system should anticipate it and rapidly increase the heat to the flask to maintain the target distillation rate. However, if the heating adjustment responds too slowly to the measured distillation rate decrease, the distillation test will fail and need to be repeated again with a fresh portion of the liquid sample, as the distillation rate is already outside the parameters set by the standard. The present invention provides a solution to avoid that.

[0054] While the distillation is proceeding at a steady rate, the reflux ring (or vapor) may settle slightly above the flask arm 23. The camera 50 monitors such reflux ring (or vapor) and the computer 52 detects any drop (or decrease) in the position of the reflux ring and may then adjust the heating of the heating element 26 (in response to detecting such a drop or decrease in the ring) in anticipation of a potential decrease in condensate flow soon enough, thus ensuring that the distillation rate (ml / min) remains within the range defined by the standard.

[0055] Methods for using the device of the present invention Referring now to FIG. 2, a flow diagram 200 illustrates the distillation test procedure of the present invention. The unknown liquid sample under test is prepared according to a selected distillation standard (e.g., ASTM D86) and placed in a distillation flask, which is then installed in a distillation assembly. If desired, the distillation can be performed automatically using an automatic analyzer. The test parameters (e.g., diameter of the support plate of the distillation flask, temperatures of the condenser and receiver, etc...) are set according to the selected distillation standard and the selected product group. The product groups include groups 1-4, which group products based on their properties (e.g., distillate type, vapor pressure, expected IBP, etc...) as described in ASTM D86-20b.

[0056] Beginning at block 210, the user first makes a selection of the group of products to be analyzed. At block 214, the distillation assembly, e.g., an automated analyzer, begins adjusting the condenser and receiver temperatures. Now that the sample has been prepared and the parameters set, the distillation process may begin. As shown at block 216, the test or analysis begins. This may be accomplished by pressing a "start" button or other similar start trigger on the distillation assembly.

[0057] The distillation process includes several stages. Referring to the process flow diagrams of Figures 1 and 2, the liquid sample in flask 12 is heated, as shown in block 220, with the heating adjusted so that the time interval between the first application of heat and the IBP is as specified in the selected test standard, while a camera takes an image of the liquid in the distillation flask and transmits the image to a computer for analysis. The analysis is useful for providing early detection of the IBP as well as adjusting the heating between the first application of heat and the IBP, as discussed above.

[0058] Once the IBP is determined, the time and temperature of the IBP are recorded, as shown in block 222 .

[0059] The liquid sample in the flask is then heated, as shown in block 230, with the heating adjusted so that the time from IBP to 5% recovery is as specified in the selected test standard, while the camera takes an image of the liquid in the distillation flask and transmits the image to a computer for analysis, which is useful for adjusting the heating to 5% recovery from IBP, as discussed above.

[0060] Once 5% recovery is determined, the time and temperature of 5% recovery is recorded, as shown in block 232 .

[0061] The liquid sample in the flask is then heated, as shown in block 240, with the heating adjusted so that the time from 5% recovery to 5 mL residue is between 4 mL-5 mL / min or as otherwise specified in the selected test standard, while the camera 50 takes an image of the liquid in the distillation flask 12 and transmits the image to the computer 52 for analysis. This analysis is useful for adjusting the heating from 5% recovery to 5 mL residue, as discussed above. As discussed above, the computer 52 analyzes the image data from the camera 50 for phenomena occurring in the sample 38 in the flask 12 and controls the heating element 26 based on the occurrence of such phenomena, thereby maintaining the distillation rate within the test parameters (e.g., the computer 52 analyzes the image from the camera 50 to identify a reflux ring / vapor in the neck 16 of the flask 12 and adjusts the heating to avoid a distillation rate that is too low).

[0062] Once the 5 mL remainder is determined, the time and temperature of the 5 mL remainder are recorded, as shown in block 242.

[0063] As heating of the liquid sample 38 continues, the camera 50 continuously monitors the liquid in the distillation flask 12. This aids in the assessment of the progress of heating and boiling. If no signs of sufficient heating or boiling are observed by the camera 50 and computer 52, the heating of the liquid sample continues or increases. However, if the onset of boiling is observed and the images from the camera 50 analyzed by the computer 52 indicate that the heating and boiling is occurring at a rate greater than adequate, the heating of the liquid sample is decreased. However, applying excessive heat to the flask 12 when there is little or no sample 38 remaining in the flask 12 to evaporate may weaken the glass of the flask 12 and cause failure (breakage) of the flask 12 during subsequent testing. Thus, the computer 52 may analyze image data from the camera 50 to determine whether sample 38 remains in the flask 12 and therefore whether further (or additional) heating should be applied. For example, when performing a test on a particular type of sample (e.g., a Type 4 sample), excess power may be applied to evaporate some of the heaviest residue remaining in flask 12, and camera 50 and computer 52 can be programmed to determine whether such excess power should be applied and, if so, when it should be turned off.

[0064] Also, after achieving the IBP, a determination is made whether the volume of distillate collected is greater than the test volume. If not, the heating of the liquid sample is continually adjusted. If the volume exceeds the test volume, the test proceeds to steps following blocks 230 and 240.

[0065] For later stages such as blocks 230 and 240, the heating control can be switched to a PID (proportional-integral-derivative) control algorithm stored in a computer or similar protocol. If desired, this control can be augmented by a camera that keeps taking images of the liquid in the distillation flask and computer analysis of these images to indicate whether boiling is proceeding properly.

[0066] According to standards (e.g., ASTM D86), there are two standard limits of time: (1) the time from the start of the test (application of heat) to the observation of the first drop of distillate in the collection flask (i.e., IBP), and (2) the time from IBP to the 5% distillation point (i.e., 5% of the first volume of the sample collected as distillate). The present invention improves on both.

[0067] FIG. 5 shows an example of a housing 30 of the present invention. As shown, the housing 30 comprises a plurality of side walls defining an interior in which the flask 12 (see FIG. 6) may be disposed. Here, the housing 30 has a first wall provided with a window 31 and an opposing wall provided with a backlight 32, which in this example forms the opposing wall. Here, the housing 30 is a multi-walled structure, and thus one or more additional walls are provided to define between the backlight wall and the camera window wall. One of these walls may be provided as a door (e.g., a movable panel 27) that an operator can open and close to access the flask 12. In some examples, the housing 30 is a three-walled enclosure, in other examples, the housing 30 is a four-walled enclosure, etc.

[0068] Figure 6 shows the housing 30 with the flask 12 in place on the base plate 28, and the movable panel 27 with the window portion 29 in an upper position. Figure 7 shows the housing 30 with the movable panel 29 in a lower position. Invention clause

[0069] The following clauses describe various aspects of the present invention.

[0070] Clause 1. A test apparatus for distilling liquid samples at atmospheric pressure, comprising: a flask having a round bottom, a neck portion and an opening at the top; a stopper for covering the top opening of the flask; a heating element in thermal communication with the flask base for heating the flask; A temperature sensor across the stopper; a condenser connected at one end to the flask; a cooling source surrounding the condenser; a receiver in communication with the condenser for receiving the distillate from the condenser; a sensor for monitoring the level and / or amount of distillate collected in the receiver during the distillation test; a camera positioned to monitor the behavior of the liquid sample in the flask during the distillation test to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; and an image analysis system for controlling the heating element based on analysis of the image data.

[0071] Clause 2. The testing apparatus of clause 1, wherein the image analysis system comprises a computer.

[0072] Clause 3. The testing apparatus of clause 2, wherein the computer analyzes image data observed by the camera during different heating stages of the distillation test.

[0073] Clause 4. The testing apparatus of clause 1, further comprising a base plate for supporting the flask, the base plate having an opening at its center and positioned between the flask and the heating element.

[0074] Clause 5. The test apparatus of clause 1, wherein the temperature detector across the stopper comprises a thermometer across the stopper, the thermometer having a tip that extends below the condenser and is positioned within the neck portion.

[0075] Clause 6. The test apparatus of clause 1, wherein a condenser is removably attached at one end to the neck portion of the flask.

[0076] Clause 7. A test device as described in clause 1, wherein the camera or cameras may be equipped with a wide-angle lens and / or a lens with an infrared (IR) filter.

[0077] Clause 8. The testing apparatus of clause 1, wherein the image analysis system comprises a backlight panel located behind the flask and opposite the camera.

[0078] Clause 9. A test apparatus as described in clause 1, wherein the backlight panel includes one or more vertical lines visible to the camera through the neck of the flask to assist in detecting reflux within the neck by changes in refractive index phenomena.

[0079] Clause 10. The testing apparatus described in clause 1, wherein the image analysis system comprises a first digital camera, a second digital camera and a computer, the first digital camera and the second digital camera being in communication with the computer, the first digital camera being for monitoring a lower portion of a flask having a round bottom and the second digital camera being for monitoring an upper portion of a flask having a neck.

[0080] Clause 11. A method for automated distillation of a liquid sample at atmospheric pressure using a test device according to any one of clauses 1 to 10, preferably under conditions strictly defined by a standard test method (e.g. ASTM D86-20b), comprising: selecting a group of products to be analyzed as liquid samples; adjusting the temperature of the condenser and the receiver; introducing a predetermined amount of liquid sample into an automated distillation assembly flask; initiating a test using a start trigger; heating a flask containing the liquid sample with a heating element; monitoring the behavior of the liquid sample in the flask during the distillation test using a camera to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; analyzing the image data in an image analysis system; detecting incipient boiling of the liquid sample using an image analysis system; measuring the temperature of the vapor in the flask with a temperature sensor; adjusting the heating by controlling the heating elements based on analysis of the image data; measuring a recovery of the distillate produced from the liquid sample and received in the receiver; and ceasing the heating when an end point of the distillation is reached.

[0081] Clause 12. The method of clause 11, further comprising determining the initial boiling point of the liquid sample.

[0082] Clause 13. The method of clause 11, further comprising determining the 5% distillation point of the liquid sample.

[0083] Clause 14. The method of clause 11, further comprising determining the final boiling point of the liquid sample.

[0084] Clause 15. The method of clause 11, further comprising the steps of determining the initial boiling point of the liquid sample, further comprising the steps of determining the 5% distillation point of the liquid sample, and further comprising the steps of determining the final boiling point of the liquid sample.

[0085] Clause 16. The method according to clause 11, wherein the image analysis system detects abnormal situations during the distillation process, such as smoke formation in the flask or accidental flask breakage, and activates available safety measures, such as an alarm.

[0086] Thus, the disclosed system and method are well adapted to obtain the ends and advantages mentioned, as well as those inherent therein. The particular embodiments disclosed above are merely illustrative. The teachings of the present disclosure may be modified and implemented in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Moreover, no limitations are intended to the details of construction or design shown herein, other than as set forth in the following claims. It will be apparent that the particular exemplary embodiments disclosed above may be altered, combined or modified, and all such variations are deemed to be within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein and / or any element disclosed herein. Although the compositions and methods are described in terms "comprising," "containing," or "including" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" various components and steps. All numbers and ranges disclosed above may vary to some extent. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range within that range is specifically disclosed. Specifically, all range values ​​disclosed herein ("from about a to about b," or equivalently, "from approximately a to b," or equivalently, "from approximately a to b") should be understood to describe all numbers and ranges encompassed within the broad range of values. Additionally, the terms in the claims have their plain and ordinary meaning unless expressly and clearly defined otherwise by the patentee. Additionally, when used in the claims, the indefinite article "a" or "an" is defined herein to mean one or more than one of the elements it introduces.In the event of a discrepancy in the use of a word or term in this specification, and in the event that there is one or more patents or other documents which may be incorporated by reference into this specification, the consistent definition in this specification shall control.

[0087] The terms "proximal" and "distal" are defined herein relative to a test operator. The term "proximal" refers to a location of an element closer to the test operator and the term "distal" refers to a location of an element further from the test operator. Additionally, the use of directional terms such as above, below, upper, lower, upward, downward, left, right, etc. are used with respect to the exemplary embodiments shown in the figures, with an upward or upward direction being toward the top of the corresponding figure and a downward or downward direction being toward the bottom of the corresponding figure.

[0088] As used herein, the phrase "at least one" preceding a series of items, along with the term "and" or "or" to separate any of the items, modifies the list as a whole, not each member (i.e., each item) of the list. The phrase "at least one" allows for the meaning to include at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" refers to only A, only B, or only C, any combination of A, B, and C, and / or at least one of each of A, B, and C, respectively.

Claims

1. 1. A test apparatus for distilling liquid samples at atmospheric pressure, comprising: a flask having a round bottom, a neck portion and an opening at the top; a stopper for covering the top opening of the flask; a heating element in thermal communication with the flask base for heating the flask; a temperature sensor across the stopper; a condenser connected at one end to the flask; a cooling source surrounding the condenser; a receiver in communication with the condenser for receiving distillate from the condenser; a sensor for monitoring the level and / or amount of the distillate collected in the receiver during a distillation test; a camera positioned to monitor the behavior of the liquid sample in the flask during the distillation test and to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; and an image analysis system for controlling the heating element based on analysis of the image data.

2. The test apparatus of claim 1 , wherein the image analysis system comprises a computer.

3. 3. The testing apparatus of claim 2, wherein the computer analyzes the image data observed by the camera during different heating stages of a distillation test.

4. 10. The testing apparatus of claim 1, further comprising a base plate for supporting the flask, the base plate having an opening in its center and positioned between the flask and the heating element.

5. 2. The test apparatus of claim 1, wherein the temperature detector across the stopper comprises a thermometer across the stopper, the thermometer having a tip that extends below the condenser and positions the tip within the neck portion.

6. 2. The testing apparatus of claim 1, wherein the condenser is removably attached at one end to the neck portion of the flask.

7. 2. The test device of claim 1, wherein the camera or cameras can be equipped with a wide-angle lens and / or an infrared (IR) filtered lens.

8. 10. The testing apparatus of claim 1, wherein the image analysis system comprises a backlight panel located behind the flask and opposite the camera.

9. 2. The testing device of claim 1, wherein the backlight panel includes one or more vertical lines visible to the camera through the neck of the flask to aid in detecting reflux within the neck by changes in refractive index phenomena.

10. 2. The testing apparatus of claim 1, wherein the image analysis system comprises a first digital camera, a second digital camera, and a computer, the first digital camera and the second digital camera being in communication with a computer, the first digital camera for monitoring a lower portion of the flask having the rounded bottom, and the second digital camera for monitoring an upper portion of the flask having the neck.

11. A method for distilling a liquid sample at atmospheric pressure, preferably under conditions defined by a standard test method (e.g. ASTM D86-20b), using a test device according to any one of claims 1 to 10, comprising the steps of: selecting a group of products to be analyzed as said liquid samples; adjusting the temperature of the condenser and the receiver; introducing a predetermined amount of said liquid sample into said automated distillation assembly flask; initiating a test using a start trigger; heating the flask containing the liquid sample with the heating element; monitoring the behavior of the liquid sample in the flask during a distillation test using the camera to obtain image data of the liquid sample, preferably of the liquid sample and of the vapor released from the liquid sample; analyzing the image data in the image analysis system; detecting incipient boiling of the liquid sample using the image analysis system; measuring the temperature of the vapor in the flask with the temperature sensor; adjusting the heating by controlling the heating elements based on the analysis of the image data; measuring the recovery of the distillate produced from the liquid sample and received in the receiver; and ceasing heating when an endpoint of said distillation is reached.

12. 12. The method of claim 11, further comprising determining the initial boiling point of the liquid sample.

13. 12. The method of claim 11, further comprising determining the 5% distillation point of the liquid sample.

14. The method of claim 11 further comprising determining the final boiling point of the liquid sample.

15. 12. The method of claim 11, further comprising the steps of determining an initial boiling point of the liquid sample, further comprising the steps of determining a 5% distillation point of the liquid sample, and further comprising the steps of determining a final boiling point of the liquid sample.

16. 12. The method according to claim 11, wherein the image analysis system detects abnormal situations during the distillation process, such as smoke formation in the flask or accidental flask breakage, and activates available safety measures, such as an alarm.

Images