An automatic full - scale continuous distillation range determination system for petroleum products

Abstract

The present invention discloses a fully automatic continuous distillation range determination system for petroleum products, which includes an automatic continuous sampling device, a distillation device, a sample receiving and reading device, and a system control device. The automatic continuous sampling device includes a sampling turntable, a constant temperature automatic sampling mechanism, and a stepping motor. The distillation device includes a distillation flask and a heating mechanism. The sample receiving and reading device includes a distillate sample receiving and reading device and a residue sample receiving and reading device. The system control device is used to control the operation of the fully automatic continuous distillation range determination system for petroleum products. The fully automatic continuous distillation range determination system for petroleum products of the present invention is an integrated determination system, which can realize automatic continuous sampling, automatic distillation, automatic measurement of the recovered volume and residues during the distillation range determination, and calculate the distillation data of the sample through atmospheric pressure correction, so as to solve the problems of inaccurate sample measurement, differences generated during sample transfer and recovery, and inability to continuously determine in traditional distillation range determination.

Description

Technical Field

[0001] The present invention relates to the technical field of distillation range determination, and specifically to a fully automatic continuous distillation range determination system for petroleum products. Background Art

[0002] The distillation range is an important quality index for evaluating the volatility of liquid fuels. It can not only indicate the boiling point range of liquid fuels, but also judge the approximate content of light and heavy components in the oil products, which is of great significance for production, use, storage and other aspects.

[0003] By measuring the distillation range of crude oil, the quantity of fractions such as gasoline, kerosene, and diesel in the crude oil can be roughly determined, thereby determining the use and processing plan of a crude oil; in a refining unit, by controlling or changing operating conditions to make the product meet the predetermined indicators, measuring the distillation range of the fuel can preliminarily determine the type of fuel according to different boiling point ranges; measuring the distillation range of engine fuel can identify its volatility, thereby judging the applicability of the oil product in use; regularly measuring the distillation range can understand the evaporation loss of the fuel and whether it is mixed with other types of oil products.

[0004] In China's mandatory national standards, the quality standards of many oil products have requirements for controlling the distillation range. For example, the distillation ranges of gasoline, diesel, and aviation kerosene all have certain range requirements, which will be accurate to a specific recovery percentage or evaporation percentage, and some even have clear requirements for the residue amount and loss amount. Moreover, in the detection process of most petroleum products, the distillation range is one of the mandatory inspection items. The domestic standard for distillation range detection is GB / T 6536, and the American standard is ASTM D86. The general idea of the method is to place the sample in a certain group according to the sample composition, vapor pressure, expected IBP or expected EP or their combination. The instrument configuration, condenser temperature, and other operating variables are defined by the group to which the sample belongs. 100 milliliters of the sample is distilled in a laboratory batch distillation device under specified conditions in an atmospheric environment and with a design providing approximately one theoretical plate. According to the user's need for data, the temperature readings and the volume of condensate, the volume of distillation residue, and the loss volume are systematically observed and recorded. At the end of the distillation, the observed temperature readings need to be corrected for atmospheric pressure, and the data is checked to see if it meets the program requirements, such as the distillation rate and loss amount. If any specified condition is not met, the test needs to be repeated. The test results are usually presented as a table or graph of the evaporation percentage or recovery percentage versus the corresponding temperature.

[0005] Most existing distillation range analyzers operate in a semi-automatic batch mode, capable of measuring only one sample at a time. Although they can automatically control the heating rate, automatically read the distillation temperature or evaporation temperature, automatically measure the volume of the distillate, and correct the temperature according to the actual atmospheric pressure, and calculate the loss based on the distillation data and residue, they cannot automatically and continuously inject samples in large quantities for sample detection. After each sample is measured, it is still necessary to replace devices such as the distillation glass flask and the first receiving graduated cylinder or flask support plate, and it is also necessary to wipe the inner tube of the condenser, which is rather troublesome and time-consuming. At the same time, due to continuous repeated operations such as loading the sample, inserting the thermometer stopper, and installing the flask onto the condenser, it is very easy for the stopper to be not tightly inserted, resulting in air leakage, which will lead to deviations in the test results and even may cause the entire experiment to fail. Since there are interfaces between the thermometer and the distillation flask, the distillation flask and the condenser, and the condenser and the first receiving graduated cylinder, the interfaces between the thermometer and the distillation flask, and the distillation flask and the condenser are generally sealed with rubber stoppers, and the interface between the condenser and the first receiving graduated cylinder is generally covered with a semi-closed cotton pad or rubber pad. Moreover, during sample transfer, the sample is mostly directly exposed to room temperature, and all these exposure situations will also increase the evaporation loss of the sample. Taking diesel as an example, the condensation temperature we generally control is 40°C, and the temperature of the graduated cylinder in the sample receiving chamber is 20°C. In fact, during normal testing, when measuring 100 mL of the sample, the indoor temperature cannot be exactly 20°C, and there is always a certain temperature difference, which will cause a difference in the volume of the measured sample and the volume read from the graduated cylinder in the sample receiving chamber due to the temperature difference. For gasoline, the temperature requirement is even lower, the distillation condensation temperature is 4°C, and the receiving temperature is 15°C, and the volume difference caused by the temperature difference of such samples will be even greater. Although we can manually increase or decrease the sample volume when measuring the sample according to experience and try to make the sample temperature close to the temperature of the receiving chamber, we still cannot avoid the volume difference caused by this temperature effect. And during sample transfer, the sample adhering to the wall of the graduated cylinder will also increase the volume difference. At the same time, since the interface between the condenser and the graduated cylinder is not fully enclosed, if the interface fit is not tight enough, when detecting light products, in the case of low temperature, water vapor in the air will condense and accumulate along the cold bath outlet section and fall to the bottom of the graduated cylinder, resulting in deviations in the test results. In addition, the residue after distillation still needs to be manually measured with a small graduated cylinder, and it is very easy to pour the zeolite into the small graduated cylinder and then pour it back for re-measurement. And since the residue is all heavy components, it is relatively viscous and adheres to the wall severely, so the measurement deviation of the residue is relatively large. To solve the above series of problems, the present invention proposes a fully automatic continuous distillation range determination system for petroleum products, in order to solve the problems such as the inability to automatically and continuously detect samples, inaccurate sample measurement, and losses during sample transfer and recovery in the existing distillation range determination process. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a fully automatic continuous distillation range determination system for petroleum products in view of the deficiencies of the prior art, which can realize automatic continuous sample injection, automatic distillation, automatic measurement of the recovered volume and residues of the distillation range, and calculate the distillation data of the sample through atmospheric pressure correction.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: a fully automatic continuous distillation range determination system for petroleum products, comprising an automatic continuous sample injection device, a distillation device, a sample receiving and reading device, and a system control device;

[0008] The automatic continuous sample injection device includes a sample injection turntable, a constant temperature automatic sample injection mechanism and a stepping motor. The sample injection turntable includes a turntable bracket and a heat preservation sleeve. The turntable bracket is coaxially and fixedly connected to the output end of the stepping motor. The heat preservation sleeve is coaxially fixed on the turntable bracket. A plurality of sample holes are equidistantly arranged in the circumferential direction of the heat preservation sleeve. Each sample hole is vertically opened and has an upper opening. The heat preservation sleeve and the constant temperature automatic sample injection mechanism are respectively located in a constant temperature control device. The temperature control range of the constant temperature control device is 5-40°C. The constant temperature automatic sample injection mechanism includes a pre-drying tube, a gas buffer, a compression pump, a sample injection needle and a volume control unit. The volume control unit includes a vertical metering tube and a six-way valve. The metering tube is a spiral glass tube. The pre-drying tube is internally provided with a desiccant and communicates with the atmosphere. The pre-drying tube, the gas buffer and the compression pump are connected in sequence. The tip of the sample injection needle faces downward and is suspended directly above one of the sample holes. The sample injection needle includes a first cavity and a second cavity which are isolated left and right. The upper end of the first cavity is a gas supply end, and the gas supply end communicates with the compression pump. An air outlet is opened on the side wall of the first cavity. An injection port is opened on the side wall of the second cavity. The injection port is close to the tip of the sample injection needle. The height of the air outlet is higher than that of the injection port. The upper end of the second cavity is a sample supply end. The sample supply end and the compression pump are respectively connected to the lower end of the metering tube through the six-way valve. The upper end of the metering tube is connected to a waste liquid discharge tube and a sample conduit through the six-way valve. The waste liquid discharge tube communicates with a waste liquid bucket;

[0009] The described distillation device includes a distillation flask and a heating mechanism. A stainless-steel sample addition tube, a first cleaning tube, and a hollow temperature probe are inserted through the rubber stopper of the distillation flask. The temperature probe is externally connected to a data processor. The upper section of the temperature probe is a thick tube, and the lower section is a thin elastic tube. The thick tube is connected to a vacuum pump through a first connecting tube. The bottom end of the thin elastic tube is connected to a hollow sintered round head, and the sintered round head has a sample outlet facing downwards. The stainless-steel sample addition tube is connected to the six-way valve through the sample conduit. The stainless-steel sample addition tube, the first cleaning tube, and the first connecting tube are respectively provided with a first valve, a second valve, and a third valve at the outlet of the distillation flask. The distillation flask has a branch tube. There are two temperature measurement points in the distillation flask and zeolite is installed. The two temperature measurement points are respectively located at the branch tube and the sintered round head. The branch tube is connected to a condenser, and the condenser is placed in the constant temperature control device. The inlet end of the condenser is inserted with a second cleaning tube, and the second cleaning tube is in parallel with the first cleaning tube. The inlet ends of the first cleaning tube and the second cleaning tube are connected to pressurized cleaning agent through a fourth valve. A fifth valve is installed on the second cleaning tube. The outlet ends of the first cleaning tube and the second cleaning tube are respectively connected with spiral nozzles. The heating mechanism is used to heat the distillation flask;

[0010] The described sample receiving and reading device includes a distillate sample receiving and reading device and a residue sample receiving and reading device. The distillate sample receiving and reading device is used to measure the distillate from the condenser and discharge its waste liquid to the waste liquid bucket; the residue sample receiving and reading device is connected to the vacuum pump. The residue sample receiving and reading device is used to measure the distillation residue from the distillation flask and discharge its waste liquid to the waste liquid bucket; the distillate sample receiving and reading device and the residue sample receiving and reading device are respectively located in the constant temperature control device;

[0011] The described system control device is used to control the operation of the full-automatic continuous distillation range determination system for petroleum products.

[0012] The working principle of the distillation range determination system of the present invention is as follows: Place the sample in a sample bottle, and then place the sample bottle in a sample hole; keep the pre-drying tube with an internal desiccant in communication with the atmosphere, filter the moisture in the air through the pre-drying tube to avoid negative pressure, and use the gas buffer connected to the rear side of the pre-drying tube to buffer the filtered air and keep the temperature of the air entering the metering tube consistent and constant; after the overall system is thermostatically stable, insert the injection needle through the rubber stopper of the sample bottle into a deep enough position in the sample bottle; the air buffered by the gas buffer is pressed into the first cavity of the injection needle by a compression pump and enters the sample bottle through the air outlet. Under the action of air pressure, the sample in the sample bottle is pressed into the second cavity, and the sample enters the lower end of the metering tube from the upper end of the second cavity. After the metering tube is filled with the sample and the sample overflows into the waste liquid bucket, through the switching of the six-way valve, a fixed volume (such as 100 mL) of the sample is blown into the distillation flask through the sample conduit and the stainless steel sampling tube, and the compression pump is used to continuously introduce thermostatic and dry air into the metering tube from the lower end of the metering tube through the gas buffer for a certain period of time, so as to blow all the samples in the metering tube and the pipeline into the distillation flask; then the sample in the distillation flask can be distilled. After the sample is distilled, it is divided into two parts. A part of the slightly lighter components are vaporized and flow out through the branch pipe of the distillation flask, cooled by the condenser, recovered and measured by the distillate sample receiving and reading device, and finally recovered by the waste liquid bucket. After the remaining slightly heavier components are distilled, they enter the vacuum pump through the thick pipe and the first connecting pipe, and are finally recovered and measured by the residue sample receiving and reading device and finally recovered by the waste liquid bucket. According to the data read by the distillate sample receiving and reading device, the residue sample receiving and reading device and the data of the temperature measurement points, after atmospheric pressure correction, the distillation data of the sample are calculated. After the distillation is completed, pressurized cleaning agent is introduced into the distillation flask and the condenser through the first cleaning pipe and the second cleaning pipe respectively to complete the cleaning and purging of the distillation flask, the condenser and the sample receiving and reading device. After drying, the sample is injected again to complete the automatic continuous detection of the sample.

[0013] Before detection, multiple sample tubes can be placed in multiple sample holes of the automatic continuous sampling device at the same time. During the determination process, the turntable bracket is rotated by a stepping motor to meet the requirements of continuous sampling. The metering tube uses the method of sampling and purging from the bottom to the top, which can meet the functions of sample pressing in, pressing out and pipeline cleaning and purging, and ensure the accuracy of the determination results. Before use, the cleaning times of the metering tube and the cleaning dosage for each cleaning can be preset through the system control device, and the purging time can be adjusted to ensure that all samples in each determination are blown into the distillation flask.

[0014] Preferably, the distillate sample receiving and reading device includes a first receiving graduated cylinder and a first liquid level tracker. A cold bath outlet receiving tube and a drain pipe are penetrated through the rubber stopper of the first receiving graduated cylinder. The inlet end of the cold bath outlet receiving tube is communicated with the outlet end of the condenser. A pressure gauge, a sixth valve and a first drying tube are successively installed on the pipeline of the drain pipe. The end of the drain pipe is externally connected to the atmosphere. The first liquid level trackers are respectively arranged on both sides of the first receiving graduated cylinder. A drainage tongue is arranged in the first receiving graduated cylinder. The drainage tongue is located directly below the outlet end of the cold bath outlet receiving tube. The bottom of the first receiving graduated cylinder is communicated with the waste liquid bucket through a waste liquid pipe. A seventh valve is installed on the waste liquid pipe.

[0015] Preferably, the residue sample receiving and reading device includes a second receiving graduated cylinder and a second liquid level tracker. A second connecting tube and a third connecting tube are penetrated through the rubber stopper of the second receiving graduated cylinder. The second connecting tube is connected to the vacuum pump. An eighth valve and a second drying tube are successively installed on the pipeline of the third connecting tube. The bottom of the second receiving graduated cylinder is communicated with the waste liquid bucket through a fourth connecting tube. A ninth valve is installed on the fourth connecting tube. The second liquid level trackers are respectively arranged on both sides of the second receiving graduated cylinder; Before using the full-automatic continuous distillation range determination system for petroleum products, first check the airtightness of the system: close all valves in advance, open the second valve and the fourth valve, fill the system with nitrogen until the pressure gauge reaches the preset pressure, then close the second valve, wait for several minutes. If the pressure of the pressure gauge does not change or the pressure drop is less than the set value, it is considered that the airtightness of the system meets the use requirements. If the pressure drop of the pressure gauge is large, disassemble and reassemble the interfaces of the system and repeatedly check the airtightness of the system until satisfactory, and then open the sixth valve to release the nitrogen and prepare for detection.

[0016] Preferably, the heat preservation sleeve includes an outer sleeve and an inner sleeve. The plurality of sample holes are equally spaced in the circumferential direction of the inner sleeve. The inner sleeve is movably installed up and down inside the outer sleeve. The function of the liftable inner sleeve is to meet the installation needs of different sample bottles. Different sample bottles (such as 150 mL, 200 mL) have the same diameter but different heights. When using a small sample bottle, the inner sleeve is lowered to the lowest position, and only the sample bottle cap can be exposed. When a large sample bottle needs to be used, the inner sleeve is pulled up.

[0017] Preferably, the length of the temperature probe is greater than the depth of the distillation flask. The thin elastic tube is bent and arranged inside the distillation flask to ensure that the sintered round head is at the lowest position inside the distillation flask and the sample outlet hole faces downward.

[0018] Preferably, the heating mechanism includes a fixed seat, multiple heating support plates, a heating support plate replacement device, and a support seat. The heating support plate replacement device includes a rotating bracket that is rotatably and vertically movably installed on the upper side of the support seat. The rotating shaft of the rotating bracket is installed on the fixed seat. The rotating bracket is located below the distillation flask. The multiple heating support plates have different sizes and are arranged at intervals in the circumferential direction of the rotating bracket. The support seat is vertically movably installed on the fixed seat. A number of cooling air inlets are provided outside the multiple heating support plates. The above heating mechanism is equipped with multiple heating support plates of different sizes to meet the detection and heating needs of different types of samples. During the detection process, the distillation flask is supported by a heating support plate of appropriate size. When replacing different types of samples, the support seat drops, and the rotating bracket drops slightly later than the support seat. After the rotating bracket drops until the heating support plate is completely separated from the distillation flask, the rotating bracket is rotated to turn a suitable pre-assembled heating support plate under the distillation flask. Then the support seat rises to lift the heating support plate until it is in close contact with the distillation flask, completing the replacement of the heating support plate. The rotating bracket then also rises to be in close contact with the heating support plate.

[0019] Preferably, a leakage detector is installed at the cooling air inlet and is externally connected to an inert gas. The leakage detector is used to detect the leakage and combustion of the sample when the distillation flask breaks, and triggers the system control device to spray inert gas into the cooling air inlet to extinguish the open fire, and at the same time triggers the system control device to lower the support seat. The design of the leakage detector can improve the safety of the measurement system of the present invention.

[0020] Preferably, the constant temperature control device uses semiconductor refrigeration technology for refrigeration, and its temperature control accuracy is 0.01 °C. The constant temperature control device is used for temperature control of the automatic continuous sampling device, the condenser, the distillate sample receiving and reading device, and the residue sample receiving and reading device. The relatively high temperature control accuracy of semiconductor refrigeration technology can ensure a faster cooling rate and improve the measurement efficiency. In particular, it can ensure that the temperature of the automatic continuous sampling device is the same as that of the distillate sample receiving and reading device to reduce the influence on the sample volume caused by the temperature difference. According to the sample type, the temperature of the residue sample receiving and reading device can be appropriately increased to avoid the condensation of the residue. For different samples, the temperature of the condenser is different, and these temperatures can be preset in advance.

[0021] Preferably, the cleaning agent is 50 °C hot petroleum ether with a boiling point of 60 - 90 °C and hot dry nitrogen at 100 °C. During cleaning and purging, petroleum ether can be used for cleaning multiple times, and finally dried with hot dry nitrogen.

[0022] Preferably, the pipelines between the sampling needle, the volume control unit, and the distillation flask, as well as the sample conduit, are all made of polytetrafluoroethylene tubes externally wrapped with thermal insulation materials.

[0023] Compared with the prior art, the present invention has the following advantages: The full-automatic continuous distillation range determination system for petroleum products of the present invention is an integrated determination system, which can realize automatic continuous sampling, automatic distillation, automatic measurement of the recovered volume and residues during the distillation range determination, and calculate the distillation data of the sample through atmospheric pressure correction, solving the problems of inaccurate sample measurement, differences generated during sample transfer and recovery, and inability to continuously determine in traditional distillation range determination. Description of the Drawings

[0024] Figure 1 Schematic diagram of the connection of the main part of the distillation range determination system in the embodiment;

[0025] Figure 2 Schematic diagram of the appearance of the automatic continuous sampling device in the embodiment;

[0026] Figure 3 Cross-sectional schematic diagram of the automatic continuous sampling device in the embodiment;

[0027] Figure 4 Schematic diagram of the effect after the sample bottle is installed in the embodiment;

[0028] Figure 5 Schematic diagram of the structure of the sampling needle in the embodiment;

[0029] Figure 6 Schematic diagram of the connection between the distillation flask and the distillate sample receiving and reading device in the embodiment;

[0030] Figure 7 Schematic diagram of the second receiving graduated cylinder and its connecting parts in the embodiment;

[0031] Figure 8 Schematic diagram of the appearance of the heating mechanism in the embodiment;

[0032] Figure 9 Schematic diagram of the appearance of the heating support plate replacement device in the embodiment;

[0033] Figure 10 Schematic diagram of the appearance of the metering tube in the embodiment;

[0034] Figure 11 Schematic diagram of the appearance of the spiral nozzle in the embodiment. Detailed Embodiments

[0035] The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

[0036] The full-automatic continuous distillation range determination system for petroleum products in the embodiment, as shown in the figure, includes an automatic continuous sampling device, a distillation device, a sample receiving and reading device, and a system control device.

[0037] In this embodiment, the automatic continuous sampling device includes a sampling turntable 11, a constant-temperature automatic sampling mechanism, and a stepping motor (not shown in the figure). The sampling turntable 11 includes a turntable bracket 12 and a heat-insulating sleeve 13. The turntable bracket 12 is coaxially and fixedly connected to the output end of the stepping motor. The heat-insulating sleeve 13 is coaxially fixed on the turntable bracket 12. The heat-insulating sleeve 13 includes an outer sleeve 14 and an inner sleeve 15. A plurality of sample holes 16 are equidistantly arranged in the circumferential direction of the inner sleeve 15. The inner sleeve 15 is movably installed inside the outer sleeve 14 in the up-and-down direction. Each sample hole 16 is vertically opened with an upper opening. The heat-insulating sleeve 13 and the constant-temperature automatic sampling mechanism are respectively located in a constant-temperature control device (not shown in the figure). The temperature control range of the constant-temperature control device is 5-40°C. The constant-temperature control device uses semiconductor refrigeration technology for refrigeration, and its temperature control accuracy is 0.01°C. The constant-temperature automatic sampling mechanism includes a pre-drying tube 21, a gas buffer 22, a compression pump 23, a sampling needle 3, and a volume control unit. The volume control unit includes a vertical metering tube 4 (100 mL, with a volume accuracy of up to 0.05 mL) and a six-way valve (not shown in the figure). The metering tube 4 is a spiral glass tube. The pre-drying tube 21 contains a desiccant and is connected to the atmosphere. The pre-drying tube 21, the gas buffer 22, and the compression pump 23 are connected in sequence. The tip of the sampling needle 3 faces downward and is suspended directly above a sample hole 16. The sampling needle 3 includes a first cavity 31 and a second cavity 32 that are isolated from each other on the left and right. The upper end of the first cavity 31 is the air supply end, which is connected to the compression pump 23. An air outlet 33 is opened on the side wall of the first cavity 31. An injection port 34 is opened on the side wall of the second cavity 32. The injection port 34 is close to the tip of the sampling needle 3. The height of the air outlet 33 is higher than that of the injection port 34. The upper end of the second cavity 32 is the sample supply end. The sample supply end and the compression pump 23 are respectively connected to the lower end of the metering tube 4 through the six-way valve. The upper end of the metering tube 4 is connected to a waste liquid discharge pipe (not shown in the figure) and a sample conduit (not shown in the figure) through the six-way valve. The waste liquid discharge pipe is connected to the waste liquid bucket 5.

[0038] In this embodiment, the distillation device includes a distillation flask 6 and a heating mechanism. A stainless-steel sample addition tube 61, a first cleaning tube 62, and a hollow temperature probe are inserted through the rubber stopper of the distillation flask 6. The temperature probe is externally connected to a data processor. The upper section of the temperature probe is a thick tube 63, and the lower section is a thin elastic tube 64. The length of the temperature probe is greater than the depth of the distillation flask 6. The thin elastic tube 64 is bent and arranged inside the distillation flask 6. The thick tube 63 is connected to a vacuum pump 66 through a first connecting tube 65. The bottom end of the thin elastic tube 64 is connected to a hollow sintered round head 67. The sintered round head 67 has a sample outlet facing downwards. The stainless-steel sample addition tube 61 is connected to the upper end of the metering tube 4 through a sample conduit and a six-way valve. First valves T1, second valves T2, and third valves T3 are respectively installed at the outlets of the stainless-steel sample addition tube 61, the first cleaning tube 62, and the first connecting tube 65 at the outlet of the distillation flask 6. The distillation flask 6 is provided with a branch pipe 81. Two temperature measurement points P1 and P2 are arranged inside the distillation flask 6 and zeolite is installed to prevent heating and boiling over. The two temperature measurement points P1 and P2 are respectively located at the branch pipe 81 and the sintered round head 67. The branch pipe 81 is connected to a condenser 82. The condenser 82 is placed inside a constant temperature control device. A second cleaning tube 83 is inserted at the inlet end of the condenser 82. The second cleaning tube 83 is in parallel with the first cleaning tube 62. The inlet ends of the first cleaning tube 62 and the second cleaning tube 83 are connected to pressurized cleaning agents through a fourth valve T4. The cleaning agents are 50°C hot petroleum ether with a boiling point of 60 - 90°C and hot dry nitrogen at 100°C. A fifth valve T5 is installed on the second cleaning tube 83. The outlet ends of the first cleaning tube 62 and the second cleaning tube 83 are respectively connected to a spiral nozzle 68 and 84 to disperse and spray the cleaning agents for easy cleaning. The heating mechanism is used to heat the distillation flask 6.

[0039] In this embodiment, the sample receiving and reading device includes a distillate sample receiving and reading device and a residue sample receiving and reading device. The distillate sample receiving and reading device is used to measure the distillate from the condenser 82 and discharge its waste liquid into the waste liquid bucket 5; the residue sample receiving and reading device is connected to the vacuum pump 66. The residue sample receiving and reading device is used to measure the distillation residue from the distillation flask 6 and discharge its waste liquid into the waste liquid bucket 5; the distillate sample receiving and reading device and the residue sample receiving and reading device are respectively located inside the constant temperature control device.

[0040] In this embodiment, the system control device is used to control the operation of the fully automatic continuous distillation range determination system for petroleum products.

[0041] In this embodiment, the distillate sample receiving and reading device includes a first receiving graduated cylinder 9 (100 mL) and a first liquid level tracker 91. A cold bath outlet receiving tube 92 and an evacuation tube 93 are penetrated through the rubber stopper of the first receiving graduated cylinder 9. The inlet end of the cold bath outlet receiving tube 92 is communicated with the outlet end of the condenser 82. A pressure gauge 94, a sixth valve T6 and a first drying tube 95 are successively installed on the pipeline of the evacuation tube 93. The end of the evacuation tube 93 is externally connected to the atmosphere. First liquid level trackers 91 are respectively arranged on both sides of the first receiving graduated cylinder 9. A drainage tongue 96 is arranged in the first receiving graduated cylinder 9. The drainage tongue 96 is located directly below the outlet end of the cold bath outlet receiving tube 92. The bottom of the first receiving graduated cylinder 9 is communicated with a waste liquid bucket 5 through a waste liquid tube 97. A seventh valve T7 is installed on the waste liquid tube 97.

[0042] In this embodiment, the residue sample receiving and reading device includes a second receiving graduated cylinder 7 (5 mL) and a second liquid level tracker 75. A second connecting tube 71 and a third connecting tube 72 are penetrated through the rubber stopper of the second receiving graduated cylinder 7. The second connecting tube 71 is connected to a vacuum pump 66. An eighth valve T8 and a second drying tube 74 are successively installed on the pipeline of the third connecting tube 72. The bottom of the second receiving graduated cylinder 7 is communicated with a waste liquid bucket 5 through a fourth connecting tube 73. A ninth valve T9 is installed on the fourth connecting tube 73. Second liquid level trackers 75 are respectively arranged on both sides of the second receiving graduated cylinder 7.

[0043] In this embodiment, the heating mechanism includes a fixed seat 101, four heating support plates 102, a heating support plate replacement device and a support seat 103. The heating support plate replacement device includes a rotating bracket 104. The rotating bracket 104 is rotatably and vertically installed on the upper side of the support seat 103. The rotating shaft of the rotating bracket 104 is installed on the fixed seat 101. The rotating bracket 104 is located below the distillation flask 6. The four heating support plates 102 are of different sizes. The four heating support plates 102 are spaced apart in the circumferential direction of the rotating bracket 104. The support seat 103 is vertically installed on the fixed seat 101. A plurality of cooling air inlets (not shown in the figure) are arranged outside the four heating support plates 102. A leakage detector (not shown in the figure) is installed at the cooling air inlet and is externally connected to an inert gas. The leakage detector is used to detect the leakage and combustion of the sample when the distillation flask 6 ruptures, and trigger the system control device to spray inert gas into the cooling air inlet to extinguish the open fire, and at the same time trigger the system control device to lower the support seat 103.

[0044] In this embodiment, the pipelines among the sampling needle 3, the volume control unit and the distillation flask 6 and the sample conduit all adopt polytetrafluoroethylene tubes wrapped with heat-insulating materials on the outside.

[0045] Before using the above distillation range determination system, its airtightness should be checked first: First, close all valves in advance, open valves T4 and T2, and fill the system with nitrogen until the pressure gauge 94 reaches the preset pressure. Then close T2 and wait for 5 minutes. If the pressure of the pressure gauge 94 does not change or the pressure drop is less than the set value, it is considered that the airtightness of the system meets the usage requirements. If the pressure drop of the pressure gauge 94 is large, disassemble and reassemble each interface of the system and repeatedly check the airtightness of the system until it is satisfactory. Then open T6 to release the nitrogen and prepare for detection.

[0046] When in use, a sequence similar to that of gas chromatography can be created first. After presetting each sample type and number on the sample injection turntable 11, when the injection temperature, cold bath temperature, recovery temperature, and residual amount receiving temperature are stable and meet the requirements, run the instrument to start detection.

[0047] The detection steps of the above distillation range determination system are as follows: First, close all valves. Then, open the first valve T1, the sixth valve T6, and the eighth valve T8 in sequence. Place the sample in the sample bottle 10, and then place the sample bottle 10 in the sample hole 16. Keep the pre-drying tube 21 with built-in desiccant in communication with the atmosphere to filter the moisture in the air through the pre-drying tube 21 to avoid negative pressure. The gas buffer 22 connected to the rear side of the pre-drying tube 21 is used to buffer the filtered air and keep the temperature of the air entering the metering tube 4 subsequently constant and consistent. After the system is thermostatically stable as a whole, insert the injection needle 3 through the rubber stopper of the sample bottle 10 to a sufficient depth inside the sample bottle 10. The air buffered by the gas buffer 22 is pressed into the first cavity 31 of the injection needle 3 through the compression pump 23 and enters the sample bottle 10 through the air outlet 33. Under the action of air pressure, the sample in the sample bottle 10 is pressed into the second cavity 32 from the injection port 34, so that the sample enters the metering tube 4 from the upper end of the second cavity 32 and overflows into the waste liquid bucket 5. After switching the six-way valve, a fixed volume (such as 100 mL) of the sample is blown into the distillation flask 6 through the stainless steel sampling tube 61, and thermostatic and dry air is continuously introduced into the metering tube 4 from the lower end of the metering tube 4 through the gas buffer 22 and the compression pump 23 for a certain period of time to blow all the samples in the metering tube 4 and the pipeline into the distillation flask 6. During the test, the injection steps generally can first preset the process of cleaning the metering tube 3 times, and then inject the sample, that is, each time about 5 - 10 mL of the sample is inhaled and then directly blown into the waste liquid bucket 5, and then the formal injection is carried out. After injection, close the first valve T1, and then the sample in the distillation flask 6 can be distilled. After the sample is distilled, it is divided into two parts. A part of the slightly lighter components are vaporized and flow out through the branch pipe 81 of the distillation flask 6, are cooled by the condenser 82, and are recovered and measured by the distillate sample receiving and reading device and finally recovered by the waste liquid bucket 5. The remaining slightly heavier components are hot and enter the vacuum pump 66 through the thick pipe 63 and the first connecting pipe 65 after the distillation is completed, and are finally recovered and measured by the residue sample receiving and reading device and finally recovered by the waste liquid bucket 5. According to the data of the sample receiving and reading device and the measurement data of each temperature measuring point, after atmospheric pressure correction, the distillation data of the sample is calculated. After the distillation is completed, when the temperature of the distillation flask 6 drops below 50 °C, close the valves T1, T6, and T8, and open all the other valves. Then open the fourth valve T4, and press 50 °C hot petroleum ether with a boiling point of 60 - 90 °C into the distillation flask 6 and the condenser 82 respectively through the first cleaning pipe 62 and the second cleaning pipe 83 to clean the distillation flask 6, the condenser 82, and the distillate sample receiving and reading device. At the same time, start the vacuum pump 66 to discharge the cleaning liquid in the distillation flask 6 to wash the residue sample receiving and reading device and collect it by the waste liquid bucket 5. The cleaning liquid in the condenser 82 will flow into the receiving graduated cylinder 9 along the condenser 82 and be collected by the waste liquid bucket 5. After flushing several times repeatedly, switch the fourth valve T4 to 100 °C hot dry nitrogen to dry the entire pipeline.Finally, turn off the vacuum pump 66 and other valves, and only open the sixth valve T6 and the eighth valve T8. Cool the distillation flask 6 by blowing air through the cooling air inlet. After the overall temperature of the instrument stabilizes and meets the requirements, the next sample can be injected for detection. Repeat this process to complete the automatic continuous detection of different samples.

Claims

1. An automatic continuous distillation range determination system for petroleum products, characterized in that, It includes an automatic continuous sampling device, a distillation device, a sample receiving and reading device, and a system control device; The automatic continuous sampling device includes a sampling turntable, a constant-temperature automatic sampling mechanism, and a stepping motor. The sampling turntable includes a turntable bracket and a heat-insulating jacket. The turntable bracket is coaxially and fixedly connected to the output end of the stepping motor. The heat-insulating jacket is coaxially fixed on the turntable bracket. A plurality of sample holes are equidistantly arranged in the circumferential direction of the heat-insulating jacket. Each sample hole is vertically opened and has an upper opening. The heat-insulating jacket and the constant-temperature automatic sampling mechanism are respectively located in a constant-temperature control device. The temperature control range of the constant-temperature control device is 5 to 40 °C. The constant-temperature automatic sampling mechanism includes a pre-drying tube, a gas buffer, a compression pump, a sampling needle, and a volume control unit. The volume control unit includes a vertical metering tube and a six-way valve. The metering tube is a spiral glass tube. The pre-drying tube is internally provided with a desiccant and is communicated with the atmosphere. The pre-drying tube, the gas buffer, and the compression pump are sequentially communicated. The tip of the sampling needle faces downward and is suspended directly above one of the sample holes. The sampling needle includes a first cavity and a second cavity that are isolated from each other on the left and right. The upper end of the first cavity is a gas supply end, and the gas supply end is communicated with the compression pump. An air outlet is provided on the side wall of the first cavity. A sampling port is provided on the side wall of the second cavity. The sampling port is close to the tip of the sampling needle. The height of the air outlet is higher than that of the sampling port. The upper end of the second cavity is a sample supply end, and the sample supply end and the compression pump are respectively communicated with the lower end of the metering tube through the six-way valve. The upper end of the metering tube is communicated with a waste liquid discharge pipe and a sample conduit through the six-way valve. The waste liquid discharge pipe is communicated with a waste liquid bucket; The described distillation device includes a distillation flask and a heating mechanism. A stainless-steel sample addition tube, a first cleaning tube, and a hollow temperature probe are inserted through the rubber stopper of the distillation flask. The temperature probe is externally connected to a data processor. The upper section of the temperature probe is a thick tube, and the lower section is a thin elastic tube. The thick tube is connected to a vacuum pump through a first connecting tube. The bottom end of the thin elastic tube is connected to a hollow sintered round head, and the sintered round head has a sample outlet facing downwards. The stainless-steel sample addition tube is connected to the six-way valve through the sample conduit. The stainless-steel sample addition tube, the first cleaning tube, and the first connecting tube are respectively equipped with a first valve, a second valve, and a third valve at the outlet of the distillation flask. The distillation flask has a branch tube. There are two temperature measurement points in the distillation flask and zeolite is installed. The two temperature measurement points are respectively located at the branch tube and the sintered round head. The branch tube is connected to a condenser, and the condenser is placed in the constant temperature control device. The inlet end of the condenser is inserted with a second cleaning tube, and the second cleaning tube is in parallel with the first cleaning tube. The inlet ends of the first cleaning tube and the second cleaning tube are connected to pressurized cleaning agent through a fourth valve. The second cleaning tube is equipped with a fifth valve. The outlet ends of the first cleaning tube and the second cleaning tube are respectively connected with spiral nozzles. The heating mechanism is used to heat the distillation flask; The described sample receiving and reading device includes a distillate sample receiving and reading device and a residue sample receiving and reading device. The distillate sample receiving and reading device is used to measure the distillate from the condenser and discharge its waste liquid into the waste liquid bucket; The residue sample receiving and reading device is connected to the vacuum pump. The residue sample receiving and reading device is used to measure the distillation residue from the distillation flask and discharge its waste liquid into the waste liquid bucket; The distillate sample receiving and reading device and the residue sample receiving and reading device are respectively located in the constant temperature control device; The described system control device is used to control the operation of the fully automatic continuous distillation range determination system for petroleum products.

2. The full-automatic continuous distillation range determination system for petroleum products according to claim 1, wherein The described distillate sample receiving and reading device includes a first receiving graduated cylinder and a first liquid level tracker. A cold bath outlet receiving tube and an emptying tube are inserted through the rubber stopper of the first receiving graduated cylinder. The inlet end of the cold bath outlet receiving tube is connected to the outlet end of the condenser. A pressure gauge, a sixth valve, and a first drying tube are successively installed on the pipeline of the emptying tube. The end of the emptying tube is externally connected to the atmosphere. The first liquid level tracker is respectively arranged on both sides of the first receiving graduated cylinder. A drainage tongue is arranged in the first receiving graduated cylinder, and the drainage tongue is directly below the outlet end of the cold bath outlet receiving tube. The bottom of the first receiving graduated cylinder is connected to the waste liquid bucket through a waste liquid tube, and a seventh valve is installed on the waste liquid tube.

3. The full-automatic continuous distillation range determination system for petroleum products according to claim 2, wherein The described residue sample receiving and reading device includes a second receiving graduated cylinder and a second liquid level tracker. A second connecting pipe and a third connecting pipe are penetrated through the rubber stopper of the second receiving graduated cylinder. The second connecting pipe is connected to the vacuum pump. An eighth valve and a second drying pipe are successively installed on the pipeline of the third connecting pipe. The bottom of the second receiving graduated cylinder is communicated with the waste liquid bucket through a fourth connecting pipe, and a ninth valve is installed on the fourth connecting pipe. The second liquid level trackers are respectively arranged on both sides of the second receiving graduated cylinder; Before using this full-automatic continuous distillation range determination system for petroleum products, first check the airtightness of the system: Close all valves in advance, open the second valve and the fourth valve, fill the system with nitrogen until the pressure gauge reaches the preset pressure, then close the second valve, wait for several minutes. If the pressure of the pressure gauge does not change or the pressure drop is less than the set value, it is considered that the airtightness of the system meets the usage requirements. If the pressure drop of the pressure gauge is large, disassemble and reassemble the interfaces of the system and repeatedly check the airtightness of the system until it is satisfactory, and then open the sixth valve to release the nitrogen and prepare for detection.

4. The full-automatic continuous distillation range determination system for petroleum products according to claim 1, wherein The described heat preservation sleeve includes an outer sleeve and an inner sleeve. A plurality of sample holes are equally spacedly arranged in the circumferential direction of the inner sleeve, and the inner sleeve is movably installed up and down inside the outer sleeve.

5. The full-automatic continuous distillation range determination system for petroleum products according to claim 1, wherein, The length of the described temperature probe is greater than the depth of the distillation flask, and the thin elastic tube is bent and arranged inside the distillation flask.

6. The fully automatic continuous distillation range determination system for petroleum products according to claim 1, wherein The described heating mechanism includes a fixed seat, multiple heating support plates, a heating support plate replacement device, and a support seat. The heating support plate replacement device includes a rotating bracket. The rotating bracket is rotatably and vertically installed on the upper side of the support seat. The rotating shaft of the rotating bracket is installed on the fixed seat. The rotating bracket is located below the distillation flask. The sizes of the multiple heating support plates are different, and the multiple heating support plates are spacedly arranged in the circumferential direction of the rotating bracket. The support seat is vertically installed on the fixed seat, and several cooling air outlets are arranged outside the multiple heating support plates.

7. The full-automatic continuous distillation range determination system for petroleum products according to claim 6, wherein A leakage probe is installed at the cooling air outlet and an inert gas is externally connected. The leakage probe is used to detect the leakage and combustion situation of the sample when the distillation flask bursts, and trigger the system control device to spray inert gas into the cooling air outlet to extinguish the open fire, and at the same time trigger the system control device to lower the support seat.

8. The full-automatic continuous distillation range determination system for petroleum products according to claim 1, wherein, The described constant temperature control device uses semiconductor refrigeration technology for refrigeration, and its temperature control accuracy is 0.01 °C.

9. The fully automatic continuous distillation range determination system for petroleum products according to claim 1, wherein The described cleaning agent is 50 °C hot petroleum ether with a boiling point of 60 - 90 °C and hot dry nitrogen at 100 °C.

10. The fully automatic continuous distillation range determination system for petroleum products according to claim 1, characterized in that The pipelines among the injection needle, the volume control unit, and the distillation flask, as well as the sample conduit, all adopt polytetrafluoroethylene tubes wrapped with heat preservation materials on the outside.

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