阅读说明：本技术 一种原油中蜡含量分析法 (Method for analyzing wax content in crude oil ) 是由 孙建军 龚争辉 刘强民 李洁 于 2019-10-31 设计创作，主要内容包括：本发明提供了一种原油中蜡含量分析法,属于测试分析技术领域。其技术方案为：一种原油中蜡含量分析法,其特征在于,具体步骤包括：用氯仿对原油进行溶解,配制成10mg/mL-20mg/mL的溶液；对色谱棒的进行预处理。点样后放置在密闭恒温恒湿槽中；在用机溶剂中进行展开；采用色谱棒对原油的蜡、油、极性物组分的相对含量进行检测。本发明的有益效果为：实现了多个样品的自动测试,大大缩短了蜡含量的测定时间和数据准确性。(The invention provides a method for analyzing the content of wax in crude oil, belonging to the technical field of test analysis. The technical scheme is as follows: the method for analyzing the content of wax in crude oil is characterized by comprising the following specific steps: dissolving crude oil with chloroform to prepare a solution of 10mg/mL-20 mg/mL; pretreatment of the chromatographic rods. After sample application, placing the sample in a closed constant temperature and humidity tank; developing in organic solvent; and detecting the relative contents of the wax, oil and polar components of the crude oil by using a chromatographic rod. The invention has the beneficial effects that: the automatic test of a plurality of samples is realized, and the determination time of the wax content and the data accuracy are greatly shortened.)

1. The method for analyzing the content of wax in crude oil is characterized by comprising the following specific steps:

dissolving crude oil with chloroform to prepare a solution of 10mg/mL-20 mg/mL;

pretreating the chromatographic rod;

after sample application, placing the sample in a closed constant temperature and humidity tank;

4) developing in organic solvent;

5) and detecting the relative contents of the wax, oil and polar components of the crude oil by using a chromatographic rod.

2. The method for analyzing the wax content in crude oil according to claim 1, wherein the step 2 is specifically: the prefabricated chromatographic rod is arranged on a rod rack, placed in a detection area of a thin-layer chromatograph, set with scanning speed and rod number, and removed with organic impurities at the high temperature of 700 ℃ in hydrogen flame to activate the chromatographic rod.

3. The method of claim 2, wherein the activated chromatographic rod is set on a sample application plate, 0.5 μ L to 1.0 μ L of the prepared oil sample is applied by a micropipette, the sample is applied at the origin of the chromatographic rod, the sample is applied again after the sample applied at the previous time is dried, the sample is applied 5 times, the sample is spread on the rod for a distance not exceeding lmm, and the chromatographic rod after the sample application is placed in a closed separation tank at a constant temperature and humidity.

4. The method for analyzing the wax content in the crude oil according to claim 3, wherein an organic solvent is added into the closed constant temperature and humidity tank, the organic solvent is 50mL of n-heptane which is used as a primary developing agent, the spotted chromatographic rod is placed into the developing tank to be developed to the vertex, and then the chromatographic rod is taken out and dried;

and adding 50mL of n-heptane serving as a secondary developing agent into the closed constant-temperature and constant-humidity tank, inverting the chromatographic rod which is developed and dried in the air at the first stage from top to bottom in the tank, developing to the middle of the rod, taking out and drying in the air.

5. The method of claim 4, wherein the developed and dried chromatographic rods are pushed together by a mechanical transmission device into a detection area of a thin layer chromatograph, a hydrogen-air ratio is adjusted, a scanning speed and a rod number are set, a voltage is set to zero, after a baseline is stabilized, scanning along the rods is started under a hydrogen flame, and a workstation is connected to record data to obtain chromatograms of various oil samples.

6. The method for analyzing the wax content in the crude oil according to claim 5, wherein the separated and dried chromatographic rod is gradually combusted through a hydrogen-rich detector in a front-back order, a sample is ionized, a measured component is ionized into positive and negative ions in a flame, the formed ion current is collected and output, an amplifier obtains a measurable electric signal after impedance conversion, and the collected electric signal is transmitted to data processing software for data calculation.

7. A chromatographic rod for analysis of wax content in crude oil, characterized in that the chromatographic rod has an inner diameter of 0.53mm, an outer diameter of 0.69mm, a quartz tube of 150mm length, a thin layer thickness of 0.05mm and a coating length of 130 mm.

8. The preparation method of the chromatographic rod based on claim 7 is characterized by comprising the following specific steps:

(1) pouring the screened silica gel or alumina and the inorganic adhesive into a closed stirrer according to the proportion of 1:2.5, adding a certain amount of solvent, and uniformly stirring the mixture to form paste for later use;

(2) cleaning the quartz tube and drying the quartz tube at 120 ℃ for 30 min;

(3) pouring the prepared uniform slurry into a container gradually, starting ultrasonic waves for 10min, and discharging mixed gas;

(4) putting the cleaned quartz tube into a container, soaking for 5min, and taking out;

(5) and introducing hot air flow into the quartz tube for 30min, and drying the solvent.

9. The method for preparing a chromatographic rod according to claim 8, wherein the inorganic binder is glass powder with a high temperature of 900-1300 ℃ and a particle size of 5 μm, the solvent is acetone, and the acetone is 2 times of the total mass of the silica gel or the alumina and the inorganic binder.

10. The container used in the preparation method of the chromatographic rod according to claim 8, which comprises a rectangular box body with a sealed bottom and an open top, wherein the rectangular box body is internally provided with an adsorbent, a support seat is inserted above the rectangular box body, a plurality of chromatographic rod insertion holes are formed in the support seat in an inserting way and are uniformly distributed, a cover with a sealed upper part is inserted above the support seat, a connecting hole is formed in the middle of the cover in an inserting way, and the connecting hole is connected with a heat source through a pipeline;

the support seat comprises a rectangular block, the chromatographic rod insertion hole is formed in the rectangular block, a rectangular frame I is externally connected to the upper portion of the rectangular block, a rectangular annular slot is formed in the rectangular frame I, the rectangular block is inserted in the rectangular box body, and the cover is inserted in the rectangular annular slot;

and a second rectangular frame matched with the rectangular block is externally connected to one side of the upper part of the rectangular box body.

Technical Field

The invention relates to the technical field of test analysis, in particular to a method for analyzing the content of wax in crude oil.

Background

The detection of the wax content in the crude oil is an important analysis project in crude oil analysis, and has very important significance for exploration and development, process design and understanding of oil reservoirs. At present, the wax content of crude oil is mainly determined by a manual elution method, the method has the disadvantages of complex operation process, high reagent consumption, generation of a large amount of toxic and harmful steam in the operation process, over 32 hours of analysis time, more uncertain factors and poor repeatability of analysis results. Therefore, a measurement method which is short in analysis time, accurate and less harmful to the human body is urgently required. The rod-shaped thin-layer chromatography is an effective detection technology for quantitative analysis of compositions of heavy oil products and the like, but a method for detecting the wax content is not provided, the application field of the rod-shaped thin-layer chromatography is expanded, and the method has important significance in realizing the rapid detection of the wax content of the crude oil.

Disclosure of Invention

The invention aims to shorten the determination time of the wax content, improve the data accuracy, reduce the analysis cost and reduce the damage of toxic reagents to operators.

The invention is realized by the following measures: the method for analyzing the content of wax in crude oil is characterized by comprising the following specific steps:

1. dissolving crude oil with chloroform to prepare a solution of 10mg/mL-20 mg/mL;

2. pretreatment of the chromatographic rods.

3. After sample application, placing the sample in a closed constant temperature and humidity tank;

4. developing in organic solvent;

5. detecting the relative contents of wax, oil and polar components of the crude oil by using a chromatographic rod;

the step 2 specifically comprises the following steps: the prefabricated chromatographic rod is arranged on a rod rack, placed in a detection area of a thin-layer chromatograph, set with scanning speed and rod number, and removed with organic impurities at the high temperature of 700 ℃ in hydrogen flame to activate the chromatographic rod.

Placing the activated chromatographic rod on a sample application plate, absorbing 0.5-1.0 microliter of prepared oil sample by using a microsyringe, applying the sample at the origin of the chromatographic rod, applying the sample at the last time after the sample applied at the previous time is dried, then performing sample application for the next time, finishing the sample application for 5 times, wherein the diffusion distance of the sample on the rod is not more than lmm, and placing the sample-applied chromatographic rod in a closed separation tank with constant temperature and constant humidity.

Adding an organic solvent into a closed constant-temperature constant-humidity tank, taking 50mL of n-heptane as a primary developing agent, placing the sample-applied chromatographic rod into a developing tank, developing to the top point, taking out and airing; adding 50mL of n-heptane serving as a secondary developing agent into the closed constant-temperature and constant-humidity tank, inverting the chromatographic rod which is developed and dried at the first stage from top to bottom in the tank to develop to the middle of the rod, taking out and drying in the air;

pushing the developed and dried chromatographic rods together into a detection area of a thin-layer chromatograph through a mechanical transmission device, adjusting hydrogen-air ratio, setting scanning speed and rod number, enabling voltage to return to zero, starting scanning along the rods under hydrogen flame after base lines are stable, and simultaneously connecting a workstation to record data to obtain the chromatogram of each oil sample. The hydrogen-air ratio is adjusted to be 80:1, the hydrogen flow is 160mL/min, the air flow is 2.0mL/min, and the scanning speed is 30 s/root.

And gradually burning the separated and dried chromatographic rod by a hydrogen-rich detector in a front-back order to ionize the sample, ionizing the detected component into positive and negative ions in flame, collecting and outputting the formed ion flow, performing impedance conversion, obtaining a measurable electric signal by an amplifier, and transmitting the collected electric signal to data processing software for data calculation.

The hydrogen-rich detector adopts the working principle that hydrogen is combusted in air as energy, combustible gas (H2) enters an ionization region from a nozzle, combustion-supporting gas (air) is introduced from the periphery, measured components are ionized into positive and negative ions in flame, the positive and negative ions move to respective opposite electrodes in an electric field formed by deflection voltage, formed ion current is collected and output, a measurable electric signal is obtained by an amplifier after impedance conversion, and the collected electric signal is transmitted to data processing software for data calculation.

The chromatographic rod is a 150mm long quartz tube with an inner diameter of 0.53mm and an outer diameter of 0.69mm, the thickness of the thin layer is 0.05mm, and the length of the coating is 130 mm. The annular chromatographic rod is light in weight, and the drying speed is accelerated due to the fact that the coating is hollow and convenient, the uniformity of the coating is guaranteed, and the use accuracy in the later period is improved.

The preparation method of the chromatographic rod is characterized by comprising the following specific steps:

(1) pouring the screened silica gel or alumina and the inorganic adhesive into a closed stirrer according to the proportion of 1:2.5, adding a certain amount of solvent, and uniformly stirring the mixture to form paste for later use;

(2) cleaning the quartz tube and drying the quartz tube at 120 ℃ for 30 min;

(3) pouring the prepared uniform slurry into a container gradually, starting ultrasonic waves for 10min, and discharging mixed gas;

(4) putting the cleaned quartz tube into a container, soaking for 5min, and taking out;

(5) and introducing hot air flow into the quartz tube for 30min, and drying the solvent.

The inorganic adhesive is glass powder with the particle size of 5 mu m and the temperature of 900-1300 ℃, the solvent is acetone, and the acetone is 2 times of the total mass of the silica gel or the alumina and the inorganic adhesive. The silica gel can be 5 micron silica gel of German Merck, the surface of the prepared rod is porous and smooth, and the oil, wax and polar substances in the crude oil can be completely separated and the separation speed is high when the sample is actually separated.

The container used in the preparation method of the chromatographic rod comprises a rectangular box body with a sealed bottom and an open top, wherein an adsorbent is arranged in the rectangular box body, a supporting seat is spliced above the rectangular box body, a plurality of chromatographic rod splicing holes are formed in the supporting seat in an opening and uniformly distributed manner, a cover with an open bottom and a sealed upper part is spliced above the supporting seat, a connecting hole is formed in the middle of the cover in a through manner, and the connecting hole is connected with a heat source through a pipeline;

the support seat comprises a rectangular block, the chromatographic rod inserting hole is formed in the rectangular block, a first rectangular frame is connected to the upper portion of the rectangular block in an external mode, a first rectangular annular slot is formed in the first rectangular frame, the rectangular block is inserted into the rectangular box body in an inserted mode, the cover is inserted into the second rectangular annular slot in an inserted mode, and a second rectangular frame matched with the rectangular block is connected to one side of the upper portion of the rectangular box body in an external mode. Inserting a tubular chromatographic rod into the jack, enabling the upper end of the tubular chromatographic rod to be slightly higher than the rectangular block, inserting the rectangular block and the tubular chromatographic rod into the rectangular box body, taking out the rectangular block after a certain time, inserting the rectangular block into the rectangular frame II, inserting the cover into the rectangular annular slot, connecting the connecting hole with a heat source, wherein the heat source can be steam, the steam finally enters the tubular chromatographic rod after entering the inside of the whole device, and the steam is quickly dried through the heat conductivity of the inner wall of the tubular chromatographic rod. Will the body is pegged graft in the chromatogram stick spliced eye, make the upper end of body be a little higher than with the rectangle piece, will the rectangle piece with the body all inserts in the rectangle box, after waiting for a certain time, take out the rectangle piece, will the rectangle piece is pegged graft on the rectangle frame two, and will the lid is pegged graft in the rectangle ring slot, then will the connecting hole is connected with the heat source, the heat source can be steam also can be the hot gas flow that 110 ℃ nitrogen source produced, and steam is through getting into inside the whole device, finally gets into the tubulose chromatogram stick, carries out rapid draing through the heat conductivity of tubulose chromatogram stick inner wall.

Compared with the prior art, the invention has the beneficial effects that: the problems that organic compounds such as wax, oil, polar substances and the like in crude oil are difficult to gasify and separate in gas chromatography and liquid chromatography is difficult to accurately and quantitatively analyze are solved, the automatic test of a plurality of samples is realized by organically combining a chromatographic rod and a hydrogen flame detector, and the wax content measuring time and the data accuracy are greatly shortened. Especially, the method is the only effective method for quantitative analysis of group composition of heavy oil products and macromolecules, simultaneously reduces the use of a large amount of organic solvents, greatly reduces the analysis cost and reduces the damage of toxic reagents to operators. In addition, the structure and the preparation method of the chromatographic rod are also limited.

Drawings

FIG. 1 is a flow chart of the preparation of a chromatographic rod.

FIG. 2 is a schematic diagram of the structure of a chromatographic rod.

Fig. 3 is a schematic view of the overall structure of the adsorbent applying apparatus.

Fig. 4 is a schematic structural diagram of a rectangular box body.

Fig. 5 is a schematic structural view of the support base.

FIG. 6 is a schematic view of the structure of the cover

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

The first embodiment is as follows:

the method for analyzing the content of wax in crude oil is characterized by comprising the following specific steps:

1. dissolving crude oil with chloroform to prepare a solution of 10mg/mL-20 mg/mL;

2. pretreatment of the chromatographic rods.

3. After sample application, placing the sample in a closed constant temperature and humidity tank;

4. developing in organic solvent;

5. detecting the relative contents of wax, oil and polar components of the crude oil by using a chromatographic rod;

the step 2 specifically comprises the following steps: the prefabricated chromatographic rod is arranged on a rod rack, placed in a detection area of a thin-layer chromatograph, set with scanning speed and rod number, and removed with organic impurities at the high temperature of 700 ℃ in hydrogen flame to activate the chromatographic rod.

Placing the activated chromatographic rod on a sample application plate, absorbing 0.5-1.0 microliter of prepared oil sample by using a microsyringe, applying the sample at the origin of the chromatographic rod, applying the sample at the last time after the sample applied at the previous time is dried, then performing sample application for the next time, finishing the sample application for 5 times, wherein the diffusion distance of the sample on the rod is not more than lmm, and placing the sample-applied chromatographic rod in a closed separation tank with constant temperature and constant humidity.

Adding an organic solvent into a closed constant-temperature constant-humidity tank, taking 50mL of n-heptane as a primary developing agent, placing the sample-applied chromatographic rod into a developing tank, developing to the top point, taking out and airing; adding 50mL of n-heptane serving as a secondary developing agent into the closed constant-temperature and constant-humidity tank, inverting the chromatographic rod which is developed and dried at the first stage from top to bottom in the tank to develop to the middle of the rod, taking out and drying in the air;

pushing the developed and dried chromatographic rods together into a detection area of a thin-layer chromatograph through a mechanical transmission device, adjusting hydrogen-air ratio, setting scanning speed and rod number, enabling voltage to return to zero, starting scanning along the rods under hydrogen flame after base lines are stable, and simultaneously connecting a workstation to record data to obtain the chromatogram of each oil sample. The hydrogen-air ratio is adjusted to be 80:1, the hydrogen flow is 160mL/min, the air flow is 2.0mL/min, and the scanning speed is 30 s/root.

And gradually burning the separated and dried chromatographic rod by a hydrogen-rich detector in a front-back order to ionize the sample, ionizing the detected component into positive and negative ions in flame, collecting and outputting the formed ion flow, performing impedance conversion, obtaining a measurable electric signal by an amplifier, and transmitting the collected electric signal to data processing software for data calculation.

The hydrogen-rich detector adopts the working principle that hydrogen is combusted in air as energy, combustible gas (H2) enters an ionization region from a nozzle, combustion-supporting gas (air) is introduced from the periphery, measured components are ionized into positive and negative ions in flame, the positive and negative ions move to respective opposite electrodes in an electric field formed by deflection voltage, formed ion current is collected and output, a measurable electric signal is obtained by an amplifier after impedance conversion, and the collected electric signal is transmitted to data processing software for data calculation.

Example two:

the method for analyzing the content of wax in crude oil is characterized by comprising the following specific steps:

1. dissolving crude oil with chloroform to prepare a solution of 10mg/mL-20 mg/mL;

2. pretreatment of the chromatographic rods.

3. After sample application, placing the sample in a closed constant temperature and humidity tank;

4. developing in organic solvent;

5. detecting the relative contents of wax, oil and polar components of the crude oil by using a chromatographic rod;

the step 2 specifically comprises the following steps: the prefabricated chromatographic rod is arranged on a rod rack, placed in a detection area of a thin-layer chromatograph, set with scanning speed and rod number, and removed with organic impurities at the high temperature of 700 ℃ in hydrogen flame to activate the chromatographic rod.

Placing the activated chromatographic rod on a sample application plate, absorbing 0.5-1.0 microliter of prepared oil sample by using a microsyringe, applying the sample at the origin of the chromatographic rod, applying the sample at the last time after the sample applied at the previous time is dried, then performing sample application for the next time, finishing the sample application for 5 times, wherein the diffusion distance of the sample on the rod is not more than lmm, and placing the sample-applied chromatographic rod in a closed separation tank with constant temperature and constant humidity.

Adding an organic solvent into a closed constant-temperature constant-humidity tank, taking 50mL of n-heptane as a primary developing agent, placing the sample-applied chromatographic rod into a developing tank, developing to the top point, taking out and airing; adding 50mL of n-heptane serving as a secondary developing agent into the closed constant-temperature and constant-humidity tank, inverting the chromatographic rod which is developed and dried at the first stage from top to bottom in the tank to develop to the middle of the rod, taking out and drying in the air;

pushing the developed and dried chromatographic rods together into a detection area of a thin-layer chromatograph through a mechanical transmission device, adjusting hydrogen-air ratio, setting scanning speed and rod number, enabling voltage to return to zero, starting scanning along the rods under hydrogen flame after base lines are stable, and simultaneously connecting a workstation to record data to obtain the chromatogram of each oil sample. The hydrogen-air ratio is adjusted to be 80:1, the hydrogen flow is 160mL/min, the air flow is 2.0mL/min, and the scanning speed is 30 s/root.

And gradually burning the separated and dried chromatographic rod by a hydrogen-rich detector in a front-back order to ionize the sample, ionizing the detected component into positive and negative ions in flame, collecting and outputting the formed ion flow, performing impedance conversion, obtaining a measurable electric signal by an amplifier, and transmitting the collected electric signal to data processing software for data calculation.

The hydrogen-rich detector adopts the working principle that hydrogen is combusted in air as energy, combustible gas (H2) enters an ionization region from a nozzle, combustion-supporting gas (air) is introduced from the periphery, measured components are ionized into positive and negative ions in flame, the positive and negative ions move to respective opposite electrodes in an electric field formed by deflection voltage, formed ion current is collected and output, a measurable electric signal is obtained by an amplifier after impedance conversion, and the collected electric signal is transmitted to data processing software for data calculation.

The chromatographic rod is a 150mm long quartz tube with an inner diameter of 0.53mm and an outer diameter of 0.69mm, the thickness of the thin layer is 0.05mm, and the length of the coating is 130 mm.

The preparation method of the chromatographic rod is characterized by comprising the following specific steps:

(1) pouring the screened silica gel or alumina and the inorganic adhesive into a closed stirrer according to the proportion of 1:2.5, adding a certain amount of solvent, and uniformly stirring the mixture to form paste for later use;

(2) cleaning the quartz tube and drying the quartz tube at 120 ℃ for 30 min;

(3) pouring the prepared uniform slurry into a container gradually, starting ultrasonic waves for 10min, and discharging mixed gas;

(4) putting the cleaned quartz tube into a container, soaking for 5min, and taking out;

(5) and introducing hot air flow into the quartz tube for 30min, and drying the solvent.

The inorganic adhesive is glass powder with the particle size of 5 mu m and the temperature of 900-1300 ℃, the solvent is acetone, and the acetone is 2 times of the total mass of the silica gel or the alumina and the inorganic adhesive. The silica gel can be 5 micron silica gel of German Merck, the surface of the prepared rod is porous and smooth, and the oil, wax and polar substances in the crude oil can be completely separated and the separation speed is high when the sample is actually separated.

The container used in the preparation method of the chromatographic rod comprises a rectangular box body 3 with a sealed bottom and an open top, an adsorbent is arranged in the rectangular box body 3, a supporting seat 4 is inserted above the rectangular box body 3, a plurality of chromatographic rod insertion holes 403 are formed in the supporting seat 4 in an opening and uniformly distributed mode, a cover 5 with a sealed upper portion is inserted above the supporting seat 4 in an inserting mode, a connecting hole 501 is formed in the middle of the cover 5 in a communicating mode, and the connecting hole 501 is connected with a heat source through a pipeline.

The supporting seat 4 comprises a rectangular block 401, the chromatographic rod inserting holes 403 are formed in the rectangular block 401, a rectangular frame I402 is externally connected to the upper portion of the rectangular block 401, a rectangular annular inserting groove 403 is formed in the rectangular frame I402, the rectangular block 401 is inserted into the rectangular box body 4, the cover 5 is inserted into the rectangular annular inserting groove 403, and a rectangular frame II 301 matched with the rectangular block 401 is externally connected to one side of the upper portion of the rectangular box body 3.

The tube body 1 is inserted into the chromatographic rod insertion hole 403, the upper end of the tube body 1 is slightly higher than the rectangular block 401, the rectangular block 401 and the tube body are inserted into the rectangular box body 3, after a certain time, the rectangular block 401 is taken out, the rectangular block 401 is inserted into the rectangular frame II 301, the cover 5 is inserted into the rectangular annular insertion groove 404, the connection hole 501 is connected with a heat source, the heat source can be steam or hot air generated by a 110 ℃ nitrogen source, the steam enters the whole device and finally enters the tube body, and rapid drying is performed through the heat conductivity of the inner wall of the tube body.

A protective cover can be arranged outside the second rectangular frame 301 for ensuring safety.

Example three:

1. taking 1 part of crude oil sample, preparing the test solution according to the test solution preparation method, adopting the chromatographic condition, carrying out continuous sample introduction for 5 times, wherein the relative retention time and the relative peak area RSD of 4 chromatographic peaks are respectively in the ranges of 0-4.87% and 0-6.54%, and the table 1 shows that the method has good precision.

2.5 parts of crude oil samples of the same batch are taken, test solutions are prepared according to a test solution preparation method, and fingerprint spectrums are respectively measured, so that the relative retention time of 4 chromatographic peaks and the relative peak area RSD are respectively 0-6.23% and 0-6.05%. Table 2 shows that the method has good reproducibility and meets the measurement requirements.

The technical features of the present invention which are not described in the above embodiments may be implemented by or using the prior art, and are not described herein again, of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions or substitutions which may be made by those skilled in the art within the spirit and scope of the present invention should also fall within the protection scope of the present invention.