Pretreatment system and method for rock total organic carbon testing

Abstract

The present invention relates to the technical field of oil and gas exploration and source rock testing and evaluation, and in particular to a pretreatment system and method for rock total organic carbon testing, including a liquid material loading device and a reaction device, the liquid material loading device including a mobile liquid injection component, an acid injection passage and a water injection passage, the mobile liquid injection component having a first liquid injection port and a second liquid injection port, a pipeline of the acid injection passage being connected to the first liquid injection port, a pipeline of the water injection passage being connected to the second liquid injection port, the reaction device including a reaction container for holding a rock sample, the mobile liquid injection component being located above the reaction device, and being movable along the arrangement direction of the reaction container so that the first liquid injection port and the second liquid injection port are aligned with the reaction container. The present invention avoids the distilled water actually entering the rock sample carrying acid reagents remaining in the pipeline due to the shared pipeline when injecting distilled water, avoids the increase of test errors due to inconsistent processing procedures of the same batch of rock samples, and improves the stability and reproducibility of test data.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration and source rock testing, and in particular to a pre-treatment system and method for testing total organic carbon in rocks. Background Art

[0002] At present, the total organic carbon (TOC) content is the primary indicator for measuring the abundance of organic matter in rocks, and is also one of the basic items that must be measured for the evaluation of source rock potential. At present, the domestic basis for determining TOC content is GB / T 19145-2003 "Determination of Total Organic Carbon in Sedimentary Rocks". The testing principle of this standard is to use dilute hydrochloric acid to remove inorganic carbon in the sample, then place the sample in a high-temperature oxygen flow to fully burn to generate CO2 and detect it with an infrared detector, and finally give the total organic carbon content. The process of "removing inorganic carbon with dilute hydrochloric acid" is also called "sample pretreatment", which is divided into steps such as "dissolving the sample", "washing the sample", and "drying the sample". The following problems exist in the sample pretreatment of actual TOC determination: ① The "sample washing" process is cumbersome. The traditional natural filtration time is about 20 to 30 minutes per time, while the requirement of "neutral filtrate" requires more than 20 cleanings, which consumes a lot of manpower throughout the process; ② The sample pretreatment process consumes nearly 90% of the test time, while the carbon-sulfur analyzer test time is only 3 to 5 minutes per sample. The mismatch between pretreatment and machine efficiency leads to low overall efficiency of TOC testing; ③ The "dissolution" endpoint is judged by the naked eye, and the degree of inorganic carbon removal lacks quantitative indicators, which is greatly affected by the technical ability and experience of the testers, resulting in large fluctuations in test data.

[0003] In the prior art, the automatic pretreatment device for rock total organic carbon test samples realizes the automation of the pretreatment process and liberates manpower, but there is still room for discussion in terms of improving test efficiency and ensuring data quality. Specifically, ① Since the acid reagent and the cleaning agent share the same conversion switch and liquid inlet pipeline (acid / water mixed injection), after the acid is added, the pipeline actually has residual acid reagent due to the existence of dead volume. If water is added to the sample at this time, what is actually added is the acid reagent or the acid-water mixture; at the same time, replacing the acid reagent with water requires several times the dead volume of liquid, so when starting the water pumping process, the liquid entering the sample is actually uncontrollable; the same problem also exists when switching from water to acid. This will introduce additional experimental errors, resulting in inaccurate data, poor repeatability and other problems. ② The bottom of the permeable sample pool is heated by a heating plate. On the one hand, the permeable sample pool is mostly made of ceramic materials with poor thermal conductivity, and it takes a long time to heat up to the target temperature; on the other hand, since the heating plate itself is not permeable, placing it at the bottom of the permeable sample pool seriously restricts the washing efficiency in the cleaning stage. Both aspects are contradictory to improving the pretreatment efficiency and shortening the pretreatment time; ③ There is a lack of effective sealing device on the top and around the sample tray, and negative pressure cannot be formed in fact, and the penetration efficiency is not improved. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is that in the existing automatic pretreatment device for rock total organic carbon test samples, the acid reagent and distilled water share the same injection pipeline, the residual acid in the injection pipeline leads to uncertainty in the amount of acid and water added, the detection data has large errors, inaccuracies, poor repeatability, and low pretreatment efficiency.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a pretreatment system for total organic carbon testing of rocks, including a liquid loading device and a reaction device, the liquid loading device including a mobile liquid injection component, an acid injection passage and a water injection passage, the mobile liquid injection component having a first liquid injection port and a second liquid injection port, the pipeline of the acid injection passage is connected to the first liquid injection port, the pipeline of the water injection passage is connected to the second liquid injection port, the reaction device includes a reaction container for holding rock samples, the mobile liquid injection component is located above the reaction device, and can be moved along the arrangement direction of the reaction container so that the first liquid injection port and the second liquid injection port are aligned with the reaction container.

[0008] Wherein, it also includes a drainage device, which includes a negative pressure component. The reaction device also includes a fixed groove and a filtrate bin. The reaction container is installed in the fixed groove, which is arranged in the filtrate bin, and a through hole is provided at the bottom of the fixed groove. The bottom wall of the reaction container is connected with the filtrate bin through the through hole. The opening of the reaction container is connected with the filtrate bin through a first sealing component. A second sealing component is provided between the bottom wall of the reaction container and the fixed groove. The negative pressure component is connected with the filtrate bin.

[0009] Wherein, the mobile liquid injection component is also provided with a CO2 detector, and the CO2 detector is located above the reaction device and directly facing the reaction container.

[0010] Wherein, the reaction device further comprises a heating assembly, the heating assembly comprises a heating component and a circulating air port, the heating component is connected to the filtrate bin via the circulating air port, and a temperature detector is also provided in the filtrate bin.

[0011] Among them, the drainage device includes a filtrate collecting tank, an ion detector and a waste liquid collection tank. The filtrate collecting tank is connected to the bottom of the filtrate tank through a pipeline, and a pump body is provided on the pipeline. The ion detector is arranged above the filtrate collecting tank through a lifting assembly, and the filtrate collecting tank is connected to the waste liquid collection tank.

[0012] Among them, the first sealing component includes a first sealing gasket, a pressure plate and a locking piece, the first sealing gasket is laid on the opening of the reaction container and the notch of the fixed groove, the pressure plate is pressed on the first sealing gasket, and the pressure plate and the filtrate bin are fixedly connected through the locking piece; the second sealing component includes a second sealing gasket and a gasket, the second sealing gasket is arranged at the bottom of the fixed groove, the reaction container is placed on the second sealing gasket, the gasket is located between the reaction container and the second sealing gasket, and the bottom surface of the second sealing gasket in contact with the gasket is an inclined surface gradually inclined downward from the outside to the center.

[0013] Among them, the mobile liquid injection component includes a robotic arm and a guide rail, the guide rail is extended along the arrangement direction of the reaction container, the robotic arm is connected to the guide rail and can move along the guide rail, and the first liquid injection port, the second liquid injection port and the CO2 detector are all arranged on the robotic arm.

[0014] Wherein, the acid injection passage includes an acid reagent bottle and a first injection pump, the first injection pump is connected to the acid reagent bottle through a first valve body, and the first injection pump is also connected to the first injection port through a pipeline, and the water injection passage includes a water reagent bottle and a second injection pump, the second injection pump is connected to the water reagent bottle through a second valve body, and the second injection pump is also connected to the second injection port through a pipeline.

[0015] Among them, it also includes a control device, which is used to control the operation of the liquid material loading device, the reaction device, and the liquid discharge device.

[0016] The present invention also provides a pre-treatment method for testing total organic carbon in rocks, comprising:

[0017] (1) Sample dissolution:

[0018] The acid reagent is injected into the crucible containing the rock sample by moving the liquid injection component to drive the acid injection passage to move;

[0019] The crucible is heated by a heating component until the temperature in the filtrate chamber reaches a preset sample dissolving temperature;

[0020] The CO2 detector is driven to move by the mobile liquid injection component to detect the CO2 gas concentration above the crucible. If the CO2 gas concentration is greater than the set CO2 gas concentration threshold, acid is injected into the reaction container again until the CO2 gas concentration above all crucibles is less than or equal to the set CO2 gas concentration threshold;

[0021] (2) Washing sample:

[0022] After the sample dissolution process is completed, the water injection passage is driven to move by the moving liquid injection assembly to inject distilled water into the crucible containing the rock sample;

[0023] The negative pressure component forms a negative pressure in the filtrate bin, and the filtrate flows into the filtrate collection tank;

[0024] The ion concentration of the filtrate in the filtrate collection tank is detected by an ion detector. If the ion concentration is greater than the set ion concentration threshold, distilled water is injected into the reaction container again until the ion concentration of the filtrate is less than or equal to the set ion concentration threshold;

[0025] The filtrate from the filtrate collection tank is discharged into the waste liquid collection tank;

[0026] (3) Sample drying:

[0027] After the sample washing process is completed, the crucible is heated again by the heating component, and the rock sample is dried at a preset drying temperature until the rock sample is completely dry.

[0028] (III) Beneficial effects

[0029] The above technical scheme of the present invention has the following advantages: the pretreatment system for total organic carbon testing of rocks in the embodiment of the present invention, the rock sample is placed in the reaction container, the liquid loading device provides independent acid injection passages and water injection passages, and the first injection port and the second injection port are independently arranged on the mobile injection component, the mobile injection component can be moved above the reaction device, the first injection port and the second injection port are both aligned with the opening of the reaction container, so that the acid reagent can be injected into the reaction container through the acid injection passage and the first injection port, the inorganic carbon in the rock sample meets the acid reagent to form CO2 gas and is discharged, and then distilled water is injected into the reaction container through the water injection passage and the second injection port, and the residual acid reagent in the rock sample reaction is cleaned and flushed out, thereby realizing the pretreatment of total organic carbon detection in the rock sample. The acid reagent and distilled water are respectively transported into the reaction container through two passages, which solves the problem of mixed injection of acid reagent and cleaning agent in the prior art, and avoids the distilled water actually entering the rock sample with residual acid reagent in the pipeline due to the shared pipeline when injecting distilled water, resulting in uncontrollable acid and water amounts actually added to the rock sample, and further causes the same batch of rock samples to introduce additional errors due to inconsistent processing procedures, resulting in inaccurate data and poor repeatability. The present invention realizes the process of efficiently removing inorganic carbon from sedimentary rocks, while improving the stability of test data.

[0030] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought about by the technical features of these technical solutions described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 12 is a schematic diagram of the structure of a pretreatment system for testing total organic carbon in rocks according to an embodiment of the present invention;

[0032] Figure 2 It is a structural schematic diagram of a mobile injection component of a pretreatment system for rock total organic carbon testing according to an embodiment of the present invention.

[0033] In the figure: 1, liquid material loading device; 2, reaction device; 3, drainage device; 4, first sealing member; 5, second sealing member; 6, control device; 7, drainage rod; 8, reset groove; 11, mobile liquid injection assembly; 12, acid injection passage; 13, water injection passage; 21, reaction container; 22, fixed groove; 23, filtrate bin; 24, heating assembly; 25, temperature detector; 31, negative pressure assembly; 32, filtrate collection tank; 33, ion detector; 34, waste liquid collection tank; 35, pump body; 36, lifting assembly; 41, first sealing pad; 42, pressure plate; 43, locking member; 51. Second sealing pad; 52. Gasket; 61. Temperature control panel; 62. Pressure control panel; 111. First liquid injection port; 112. Second liquid injection port; 113. CO2 detector; 114. Robotic arm; 115. Guide rail; 121. Acid reagent bottle; 122. First injection pump; 123. First valve body; 131. Water reagent bottle; 132. Second injection pump; 133. Second valve body; 241. Heating component; 242. Circulating air outlet; 611. Digital display screen; 612. Emergency switch; 621. Negative pressure regulating valve; 622. Negative pressure gauge; 623. Emergency switch. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In addition, in the description of the present invention, unless otherwise specified, "multiple", "multiple roots", and "multiple groups" mean two or more, and "several", "several roots", and "several groups" mean one or more.

[0037] like Figure 1 and Figure 2 As shown, a pretreatment system for total organic carbon testing of rocks provided by an embodiment of the present invention comprises a liquid loading device 1 and a reaction device 2, wherein the liquid loading device 1 comprises a mobile liquid injection component 11, an acid injection passage 12 and a water injection passage 13, wherein the mobile liquid injection component 11 has a first liquid injection port 111 and a second liquid injection port 112, wherein a pipeline of the acid injection passage 12 is connected to the first liquid injection port 111, and a pipeline of the water injection passage 13 is connected to the second liquid injection port 112, and the reaction device 2 comprises a reaction container 21 for holding a rock sample, wherein the mobile liquid injection component 11 is located above the reaction device 2, and can be moved along the arrangement direction of the reaction container 21 so that the first liquid injection port 111 and the second liquid injection port 112 are aligned with the reaction container 21.

[0038] The pretreatment system for rock total organic carbon testing of the embodiment of the present invention, the reaction container contains rock samples, the liquid material loading device provides independent acid injection passages and water injection passages, and the first injection port and the second injection port are independently arranged on the mobile injection assembly, the mobile injection assembly can move above the reaction device, the first injection port and the second injection port are aligned with the opening of the reaction container, so that the acid reagent can be injected into the reaction container through the acid injection passage and the first injection port, the inorganic carbon in the rock sample meets the acid reagent to form CO2 gas and is discharged, and then distilled water is injected into the reaction container through the water injection passage and the second injection port, and the residual acid reagent in the rock sample reaction is washed out, thereby realizing the pretreatment of total organic carbon detection in the rock sample. The acid reagent and distilled water are respectively transported into the reaction container through two passages, which solves the problem of mixed injection of acid reagent and cleaning agent in the prior art, and avoids the distilled water actually entering the rock sample due to the shared pipeline when injecting distilled water. The distilled water actually entering the rock sample carries the acid reagent remaining in the pipeline, and the amount of acid and water actually added to the rock sample cannot be controlled, resulting in inconsistent processing procedures for the same batch of rock samples, introducing additional errors, and causing inaccurate data and poor repeatability. The present invention realizes the process of efficiently removing inorganic carbon in sedimentary rocks and improves the stability of test data at the same time.

[0039] Among them, the pretreatment system for rock total organic carbon testing of the embodiment of the present invention also includes a drainage device 3, the drainage device 3 includes a negative pressure component 31, the reaction device 2 also includes a fixed groove 22 and a filtrate bin 23, the reaction container 21 is installed in the fixed groove 22, the fixed groove 22 is arranged in the filtrate bin 23, and a through hole is provided at the bottom of the fixed groove 22, the bottom wall of the reaction container 21 is connected with the filtrate bin 23 through the through hole, the opening of the reaction container 21 is connected with the filtrate bin 23 through a first seal 4, and a second seal 5 is provided between the bottom wall of the reaction container 21 and the fixed groove 22; the negative pressure component 31 is connected with the filtrate bin 23.

[0040] In this embodiment, distilled water is added to the reaction vessel, and the residual acid reagent in the rock sample is mixed with the distilled water to form a filtrate, which infiltrates into the filtrate bin through the bottom of the reaction vessel and the through holes at the bottom of the fixed tank under the action of gravity. During the repeated water addition process, some low-density rock samples will float on the liquid surface, or climb along the inner wall of the reaction vessel with the water (this height is higher than the liquid surface because of the wettability of water to the inner wall of the reactor), and a certain height needs to be reserved; and if the position of the rock sample in the reactor is too high, it will lead to potential risks: first, the rock sample overflows along the upper edge of the reactor, resulting in the loss of the rock sample; second, in subsequent tests, the combustion degree of the rock sample in the upper part of the reaction vessel is not as good as that of the rock sample in the lower part, and the total organic carbon determination must ensure that the rock sample is fully burned. Both of these risks will affect the data quality of the total organic carbon test and may even cause the failure of the entire test. Therefore, in order to control the sample height in the reaction vessel, the water added each time needs to be completely filtered as much as possible within the water adding cycle. Therefore, in addition to strictly controlling the amount of water added each time, it is also necessary to start the negative pressure component to provide negative pressure in the process of the liquid in the reaction vessel filtering into the filtrate bin, accelerate the filtration of the liquid, and improve efficiency. In this embodiment, the negative pressure component uses a vacuum pump and a vacuum pipeline. The vacuum pump is connected to the filtrate bin through the vacuum pipeline. The vacuum pump is started to form a negative pressure in the filtrate bin through the vacuum pipeline. In this embodiment, due to the small amount of liquid added at a single time, the limited volume of the reaction vessel and the limitation of the liquid level, the general single amount of liquid added does not exceed 2mL. In addition, due to the filtration resistance of the reaction vessel, the actual amount of liquid filtered out is not only small, but also slow, and it is more infiltrated in the form of a water film, which is difficult to form water droplets or water columns to flow out smoothly. Therefore, a drainage rod 7 is also provided at the through hole of the fixed groove to guide the filtrate and accelerate the flow of the filtrate to the filtrate bin.

[0041] In this embodiment, in order to ensure the effective effect of the negative pressure component on the filtrate bin, an effective seal is set on the upper part and the periphery of the reaction container to ensure the good formation of the negative pressure environment when the negative pressure component is in operation, thereby improving the infiltration efficiency. Therefore, the bottom of the reaction container and the fixed groove are sealed by a first seal, and the top opening of the reaction container and the filtrate bin are sealed by a second seal, so that the notch of the fixed groove and the through hole at the bottom of the groove that connects the filtrate bin to the outside world are sealed, ensuring the formation of a negative pressure environment inside the filtrate bin.

[0042] In this embodiment, the reaction container is a pre-calcined TOC special crucible, and the filtrate bin is a conical filtrate bin, which is convenient for the filtrate seeping from the reaction container to be collected and discharged.

[0043] Among them, the mobile injection assembly 11 is also provided with a CO2 detector 113, which is located above the reaction device 2 and directly facing the reaction container 21. The mobile injection assembly is located above the reaction device. As the mobile injection assembly moves, the acid injection passage injects the acid reagent into the reaction container through the first injection port. After the rock sample reacts with the acid reagent for a period of time, the mobile injection assembly moves again, driving the CO2 detector thereon to move to the top of the reaction container and close to the opening of the reaction container, so as to detect in real time the concentration of CO2 gas released after the rock sample reacts with the acid reagent in the reaction container. If the CO2 gas concentration above the rock sample is greater than the set threshold, it means that the rock sample and the acid reagent have not reacted completely. At this time, the acid injection passage injects the acid reagent into the reaction container again through the first injection port, and repeats the acid addition process until the CO2 gas concentration above the rock sample is less than or equal to the set threshold.

[0044] Wherein, the reaction device 2 also includes a heating assembly 24, and the heating assembly 24 includes a heating component 241 and a circulating air port 242. The heating component 241 is communicated with the filtrate storehouse 23 through the circulating air port 242, and a temperature detector 25 is also provided in the filtrate storehouse 23. The heating assembly is responsible for realizing the uniform family and constant temperature maintenance of the reaction area in the filtrate storehouse and subsequent sample drying. In the present embodiment, the hot fan and the heating block constitute the heating component. After the acid reagent is injected into the reaction vessel in the acid injection passage, the hot fan discharges air after being heated by the heating block, and the heat is blown into the filtrate storehouse through the circulating air port, and the reaction vessel in the fixed tank is heated by hot air bath circulation. When the temperature detector in the filtrate storehouse detects that the set temperature is reached, the heating component controls the heating temperature to keep the temperature in the filtrate storehouse, enters the constant temperature mode, and the rock sample reacts with the acid reagent to release CO2 gas under constant temperature conditions. In the water injection passage, distilled water is repeatedly injected into the reaction vessel, and after the cleaning of the rock sample is completed, the heating assembly is automatically turned on again, and the temperature in the filtrate storehouse is regulated to the set drying temperature, and the sample is completely dried.

[0045] The hot fan and heating block used in this embodiment heat the filtrate bin in a hot air bath cycle through a circulating seal. Compared with the prior art method of using a heating plate to heat the bottom of a water-permeable sample pool made of ceramic material, the temperature rises more rapidly. In addition, the present invention replaces the heating plate, avoiding the problem that the heating plate itself is impermeable and is placed at the bottom of the water-permeable sample pool, which seriously restricts the washing efficiency in the cleaning stage. Therefore, the pretreatment efficiency is improved and the time required for pretreatment is shortened. In other embodiments, the heating component may also adopt other heating forms that do not hinder the permeability of the reaction container and the fixed tank, and ensure that the temperature rises quickly and stably, such as water bath heating or heating with a heating rod or other heating element.

[0046] Among them, the drainage device 3 includes a filtrate collection tank 32, an ion detector 33 and a waste liquid collection tank 34. The filtrate collection tank 32 is connected to the bottom of the filtrate bin 23 through a pipeline, and a pump body 35 is provided on the pipeline. The ion detector 33 is arranged on the filtrate collection tank 32 through a lifting assembly 36, and the filtrate collection tank 32 is connected to the waste liquid collection tank 34. The drainage device is responsible for the collection and real-time monitoring of endpoint identification indicators, providing a basis for judgment for the instrument automation process, and uniformly collecting experimental waste liquid. In this embodiment, the filtrate of each cleaning cycle is accelerated by the pump body, flows from the bottom of the filtrate bin along the pipeline into the filtrate collection tank, and the pH value and Cl are measured in the filtrate collection tank. - Other parameters such as ion concentration or conductivity can be detected. In this embodiment, the ion detector can be a pH detector or a Cl - The detector and lifting assembly use a clamp and an automatic lifting track. The clamp fixes the pH detector / Cl - The detector moves up and down on the automatic lifting track and repeatedly enters the filtrate collection tank to measure the pH value or Cl - Ion concentration detection, up to pH or Cl - When the ion concentration is less than or equal to the set threshold, it is considered that the cleaning end point has been reached, and the water injection passage no longer circulates the water injection process in the reaction container. After the test is completed, the filtrate enters the waste liquid collection pool through the waste pipe.

[0047] Due to the differences in the configuration of the "carbon and sulfur analyzer" models that will be installed later, for those equipped with a halogen absorption tower, it is recommended to use a pH detector, which can further shorten the sample processing time; for those not equipped with a halogen absorption tower, it is recommended to use a Cl - The detector can remove most of the soluble chlorides, avoid the generation of acidic gases in high temperature air, and cause corrosion of the "carbon sulfur analyzer" pipeline, and also avoid possible interference with the detector. - The test can be set according to user needs. - The advantages of the test are: ① H in the solution is higher than that in the pH test. +1. Lower ion concentration; 2. Greatly reduce the chloride content in the solution, avoid high-temperature decomposition of chloride to produce a large amount of HCl during subsequent measurements, which will cause corrosion to the pipelines of subsequent detection instruments, protect subsequent equipment; at the same time, prevent possible interference with the detector and improve the accuracy of the test results.

[0048] Among them, the first sealing member 4 includes a first sealing gasket 41, a pressing plate 42 and a locking member 43, the first sealing gasket 41 is laid on the opening of the reaction vessel 21 and the notch of the fixed groove 22, the pressing plate 42 is pressed on the first sealing gasket 41, and the pressing plate 42 is fixedly connected with the filtrate bin 23 through the locking member 43; the second sealing member 5 includes a second sealing gasket 51 and a gasket 52, the second sealing gasket 51 is arranged at the bottom of the fixed groove 22, the reaction vessel 21 is placed on the second sealing gasket 51, the gasket 52 is located between the reaction vessel 21 and the second sealing gasket 51, and the bottom surface of the second sealing gasket 51 in contact with the gasket 52 is an inclined surface that gradually tilts downward from the outside to the center. The arrangement of the first sealing member and the second sealing member can maximize the flexibility of the reaction vessel selection and the adaptability in production practice while ensuring the environmental sealing of the filtrate bin. The second sealing gasket of the second sealing member is an elastic sealing gasket. The surface of the elastic sealing gasket matching with the reaction container is conical and can adapt to different outer diameters of reaction containers. An annular gasket group is arranged between the elastic sealing gasket and the bottom surface of the reaction container to adjust the height of the reaction container so that the top surface of the reaction container and the filtrate bin are as flush as possible. The first sealing gasket of the first sealing member is an elastic sealing gasket. An elastic sealing gasket is arranged at the opening of the reaction container after setting and at the notch of the surrounding fixed groove. A rigid compacting plate is placed above all elastic sealing gaskets, and a locking piece is used to fasten the rigid compacting plate to the filtrate bin at its edge.

[0049] In this embodiment, since the outer diameter of the reaction container is smaller than the inner diameter of the fixed groove, there is a gap between the reaction container and the fixed groove. In order to ensure the airtightness between the filtrate bin and the fixed groove and the reaction container, a first seal is provided to isolate the gap between the fixed groove and the reaction container from the outside world, and to isolate the internal space of the filtrate bin from the outside world. A second seal is provided to isolate the gap between the fixed groove and the reaction container from the internal space of the filtrate bin, thereby achieving the best sealing effect and ensuring the subsequent formation of a negative pressure environment in the filtrate bin.

[0050] Among them, the mobile liquid injection component 11 includes a mechanical arm 114 and a guide rail 115, the guide rail 115 is extended along the arrangement direction of the reaction container 21, the mechanical arm 114 is connected to the guide rail 115, and can move along the guide rail 115, and the first liquid injection port 111, the second liquid injection port 112 and the CO2 detector 113 are all arranged on the mechanical arm 114. In this embodiment, the mechanical arm is on the guide rail and moves along the guide rail, the guide rail is extended along the arrangement direction of the reaction container, the mechanical arm is located above the reaction container, and the first liquid injection port, the second liquid injection port and the CO2 detector are all arranged on the surface close to the mechanical arm and the reaction container. In this embodiment, the fixed slots in the filtrate bin are arranged in a rectangular array, with 5 fixed slots in each column, and each fixed slot is equipped with a reaction container, and 5 first liquid injection ports, 5 second liquid injection ports and 5 CO2 detectors are also correspondingly arranged on the mechanical arm.

[0051] During the acid injection process, a set volume of acid reagent is injected into a row of 5 reaction containers through the pipeline set of the acid injection passage carried by the robotic arm, and the reaction containers in other rows are filled with acid reagents in sequence by the robotic arm moving from right to left on the guide rail. After the acid is added to all the reaction containers, the robotic arm returns to the reset groove 8.

[0052] After waiting for a certain period of time for the rock sample in the reaction container to react with the acid reagent, the robotic arm moves again to the top of a row of 5 reaction containers, and the CO2 detector faces the opening of the reaction container to detect the CO2 gas concentration generated in the reaction containers in the row. If the CO2 gas concentration above a reactor is greater than the set threshold, it means that the rock sample in the reaction container and the acid reagent have not reacted completely. At this time, the acid injection passage injects the acid reagent into the reaction container again through the first injection port corresponding to the reaction container, and repeats the acid addition process until the CO2 gas concentration above the reaction container is less than or equal to the set threshold. The robotic arm then moves to the next row of reaction containers to detect the CO2 gas concentration. After the detection is completed, the robotic arm returns to the reset slot 8.

[0053] During the water injection process, a set volume of distilled water is injected into a row of 5 reaction containers through the pipe set of the water injection passage carried by the robot arm, and the reaction containers in other rows are washed with distilled water in turn by the robot arm running from right to left on the guide rail. Since the rock samples in each reaction container need to be washed more than dozens of times, the negative pressure can ensure that the water in the first column has been completely filtered within one water addition cycle, so that the liquid level is always controlled below 2 / 3 of the internal height of the reaction container. In order to shorten the processing time of rock samples, when the robot arm completes the water injection work of all reaction containers from right to left in turn, it automatically repeats the second and third distilled water additions from the first column from the right... until the cleaning end is reached, and the robot arm returns to the reset slot 8.

[0054] Wherein, the acid injection passage 12 comprises an acid reagent bottle 121 and a first injection pump 122, the first injection pump 122 is communicated with the acid reagent bottle 121 through a first valve body 123, and the first injection pump 122 is also communicated with the first injection port 111 through a pipeline, and the water injection passage 13 comprises a water reagent bottle 131 and a second injection pump 132, the second injection pump 132 is communicated with the water reagent bottle 131 through a second valve body 133, and the second injection pump 132 is also communicated with the second injection port 112 through a pipeline. In the present embodiment, the acid reagent and distilled water are respectively loaded into the acid reagent bottle and the water reagent bottle, and are placed together in the reagent tank, the acid reagent bottle is sequentially connected to the first valve body and the first injection pump through a hose, and the water reagent bottle is sequentially connected to the second valve body and the second injection pump through a hose. In the present embodiment, the first valve body and the second valve body both adopt a six-way valve. The first injection pump sucks acid reagent through the six-way valve, switches the six-way valve and passes the acid reagent into the pipeline of the acid injection passage carried by the robotic arm; the second injection pump sucks distilled water through the six-way valve, switches the six-way valve and passes through the pipeline of the water injection passage carried by the robotic arm, thus forming two completely independent injection passages. The multi-way valve ensures the relative independence of acid and water addition for each rock sample, realizes precise control of the amount of liquid added, and avoids cross-interference between different rock samples.

[0055] Among them, the pretreatment system for rock total organic carbon testing in the embodiment of the present invention also includes a control device 6, which is used to control the operation of the liquid material loading device 1, the reaction device 2, and the liquid discharge device 3. In this embodiment, the automation process of all hardware can be controlled by independent external software or by an embedded control panel. According to the properties of the rock sample, sub-processes such as "dissolving sample", "washing sample", and "drying sample" are edited or imported. Each device of the system enters the standby / ready state, the automatic control program is started, and the device will perform a power-on self-test.

[0056] The control device 6 of this embodiment includes a temperature control panel 61 and a pressure control panel 62. The temperature control panel 61 includes a digital display screen 611 and an emergency switch 612, which are used to control the operation of the heating component, control the heating component to automatically start heating, and display the set and real-time temperatures on the digital display screen at the same time. The emergency switch is a safety emergency measure, and the heating component is manually turned off when the safety alarm sounds. The pressure control panel 62 includes a negative pressure regulating valve 621, a negative pressure gauge 622 and an emergency switch 623, which are used to control the operation of the negative pressure component. The negative pressure level in the filtrate bin is controlled by the negative pressure regulating valve on the pressure control panel, and the negative pressure value is displayed in real time by the negative pressure gauge to monitor the sealing state during the treatment process. The negative pressure is not the greater the better. Due to the different particle sizes of rock samples and the density of the reaction container, blindly increasing the negative pressure may cause the rock sample to pass through the bottom of the reaction container, resulting in sample loss, which has an adverse effect on the test results. Therefore, for different rock sample particle sizes and reaction containers with different densities, it is necessary to adjust the vacuum degree in the filtrate bin to a suitable range. The emergency switch is a safety emergency measure. When the safety alarm sounds, the negative pressure component is manually closed. The control device can also control the filtrate detection timing through software, that is, control the operation of the ion detector. After the pre-treatment is completed, the control device control system automatically cleans all pipelines, then enters the standby state, and prompts that the treatment is completed. The computer programs and instructions involved in the automatic control are all available in the prior art, and the embodiments of the present invention will not be repeated.

[0057] The present invention also provides a pre-treatment method for testing total organic carbon in rocks, comprising:

[0058] S1, rock sample preparation and fixation:

[0059] ① Weigh the rock sample of specified particle size and mass and put it into the reaction container, and place the reaction container containing the rock sample in the fixed tank;

[0060] ② The second sealing member is placed under the reaction container to adjust the height of the reaction container in the fixing groove so that it matches the first sealing member at the notch of the fixing groove;

[0061] ③ After the reaction vessel is sealed, the first sealing gasket and the pressure plate are added to the opening of the reaction vessel in sequence, and the edge of the pressure plate is fastened with a locking piece to complete the preparatory work of automatic processing.

[0062] S2, reagent preparation and instrument self-test:

[0063] ① Put the prepared acid reagent and distilled water into the acid reagent bottle and the water reagent bottle respectively, and place them together in the reagent tank, connect the acid reagent bottle with the corresponding six-way valve and the first injection pump with a connecting hose, and connect the water reagent bottle with the corresponding six-way valve and the second injection pump with a connecting hose;

[0064] ② Start the automatic control program, the system will perform a power-on self-test; edit or import sub-processes such as "dissolving samples", "washing samples", and "drying samples" according to the properties of the rock samples, and the system will enter the standby / ready state.

[0065] S3, automatic "dissolving sample" process:

[0066] ① The acid reagent is injected into the crucible containing the rock sample by driving the acid injection passage to move the liquid injection assembly; the first injection pump sucks the acid reagent in the acid reagent bottle through the six-way valve, switches the six-way valve, and pumps a set volume of acid reagent into a column of reaction containers through the pipeline set of the acid injection passage carried by the robotic arm; the reaction containers in other columns are sequentially added with acid reagents by the robotic arm running from right to left on the guide rail; after all reaction containers are fully acidified, the robotic arm returns to the reset slot;

[0067] ② Heat the crucible through the heating component until the temperature in the filtrate chamber reaches the preset dissolution temperature; the temperature control panel automatically starts heating, and the set and real-time temperatures are displayed on the digital display screen at the same time; the heating component heats the inside of the filtrate chamber through the circulating air outlet to circulate the heat in a hot air bath, and enters the constant temperature mode when the temperature sensor reaches the preset dissolution temperature;

[0068] ③ The CO2 detector is driven to move by the mobile liquid injection component to detect the CO2 gas concentration above the crucible. If the CO2 gas concentration is greater than the set CO2 gas concentration threshold, acid is injected into the reaction container again until the CO2 gas concentration above all crucibles is less than or equal to the set CO2 gas concentration threshold; the inorganic carbon in the rock reacts with the acid reagent under constant temperature conditions to release CO2 gas, and the CO2 detector detects the CO2 gas concentration above the rock sample position in real time. If the CO2 gas concentration above the rock sample position in a reaction container is greater than the set CO2 gas concentration threshold, it means that the rock sample and the acid reagent have not reacted completely. At this time, the robotic arm will repeat the above acid addition process again until the CO2 gas concentration above all rock samples is less than or equal to the set CO2 gas concentration threshold, and the "dissolution" process is considered to be completed.

[0069] S4, automatic "sample washing" process:

[0070] ① After the dissolution process is completed, the injection assembly is moved to drive the water injection passage to inject distilled water into the crucible containing the rock sample; the second injection pump sucks the distilled water in the water reagent bottle through the six-way valve, switches the six-way valve, and pumps a set volume of distilled water into a column of reaction containers through the pipe set of the water injection passage carried by the robotic arm; the reaction containers in other columns are washed with distilled water in sequence by the robotic arm running from right to left on the guide rail. Since each rock sample requires more than dozens of washes, in order to shorten the sample processing time, when the robotic arm has added all the reaction containers in sequence from right to left, it automatically repeats the second and third distilled water additions starting from the first column from the right... until the washing end is reached;

[0071] ② The negative pressure component is used to form a negative pressure in the filtrate bin, and the filtrate flows into the filtrate collection tank; in the process of repeated water addition, in order to avoid overflow of excessive water in the reaction container, the water added each time needs to be filtered as completely as possible within the water addition cycle. Therefore, in addition to controlling the amount of water added each time, the negative pressure component needs to be started to accelerate the filtration. Start the vacuum pump and form a negative pressure in the filtrate bin through the vacuum pipeline. The degree of negative pressure is controlled by the negative pressure regulating valve on the pressure control panel, and the negative pressure value is displayed in real time by the negative pressure gauge; at the same time, the drainage rod will accelerate the flow of the filtrate.

[0072] ③ The filtrate in the filtrate collection pool is tested for pH by an ion detector. If the pH is greater than the set pH threshold, distilled water is added to the reaction vessel again until the pH of the filtrate is less than or equal to the set pH threshold. The pump body is accelerated to enter the filtrate collection pool, and the pH value or Cl is measured in the filtrate collection pool. - Ion concentration detection; the holder holds the pH detector / Cl - The detector is on the automatic lifting track and the software controls the filtrate detection timing until the pH value or Cl - When the ion concentration is less than or equal to the set pH threshold, it is considered that the cleaning end point has been reached. At this time, the second injection pump no longer performs the circulating water adding process, and the robot arm returns to the reset tank;

[0073] ④ The filtrate in the filtrate collection tank is discharged into the waste liquid collection tank; the tested filtrate enters the waste liquid collection tank through the waste discharge pipe.

[0074] S5, automatic "sample drying" process:

[0075] ① After the sample washing process is completed (after reaching the cleaning end point), the crucible is heated again by the heating component, and the rock sample is dried at the preset drying temperature until the rock sample is completely dry.

[0076] S6, shutdown:

[0077] ①After completing the above processing steps, the system automatically cleans all pipes and then enters the standby state; and prompts that the experiment is completed;

[0078] ② It is necessary to manually adjust the pH detector / Cl - The detector is placed in protective liquid to ensure the sensitivity of the detector and extend the life of the detector.

[0079] The specific example of the pre-treatment method for rock total organic carbon testing is as follows:

[0080] S1, ① Crush the black shale into 80-140 mesh, mix and divide the samples evenly, and number them LZZ. The special crucible for TOC is calcined at 1000℃-1200℃ for not less than 2 hours, cooled in a drying dish and set aside. Weigh 40 portions of LZZ samples and put them into 40 special crucibles for TOC, each sample is about 80 mg. ② Use stainless steel tweezers to place the 40 crucibles containing samples into the 40 sample positions of the instrument respectively. Since standard size crucibles are used this time, there is no need to add a ring gasket set. ③ After sealing, add elastic sealing pads and rigid compaction plates to the upper part of the crucible in turn, and tighten them with a locking device.

[0081] S2, ① The acid reagent used in this experiment is made of analytical pure hydrochloric acid according to HCl:H2O=1:7 (volume ratio), placed in the acid reagent bottle, and the connecting hose is inserted into the bottom of the reagent bottle; similarly, distilled water is placed in the water reagent bottle, and another connecting hose is inserted into the bottom of the reagent bottle (the instrument itself has connected the two connecting hoses to the corresponding injection pumps through the six-way valve, no additional operation is required). ② Start the self-test and set the "dissolving sample", "washing sample" and "drying sample" control processes respectively.

[0082] S3, "Dissolution" process settings: the acid volume of each sample is 2mL, and the addition is completed within 5s; the reaction temperature is 60℃; the CO2 gas concentration detection duration is 10s, and the threshold is set to 20ppm.

[0083] S4, "sample washing" process settings: the water volume of each sample is 2mL, and the addition is completed within 5s; the vacuum degree is set to 0.09MPa; Cl - The duration of ion concentration detection was 20 s, and the threshold was set at 20 ppm.

[0084] S5, “Sample drying” process setting: Set the sample drying temperature to 60℃.

[0085] S6, shut down; remove Cl - Place the detector in the protective solution and take it out when it is used next time.

[0086] Test results comparison

[0087] (1) Processing efficiency: To achieve the cleaning effect of this experiment ([Cl-] ≤ 20 ppm), the sample needs to be cleaned 50 times. The traditional manual method cleans once every 30 minutes and the continuous cleaning time is up to 25 hours. The present invention does not require manual supervision, and the single batch processing time is about 6 hours, which is less than 25% of the time of the manual method, and the processing efficiency is significantly improved.

[0088] (2) Data quality: The average TOC value measured by the manual method was 0.52%, the data range was 0.21%, and the relative standard deviation RSD was 9.37%; the average TOC value measured by the present invention was 0.50%, the data range was 0.06%, and the relative standard deviation RSD was 2.61%, and the test data quality was significantly improved.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pretreatment system for rock total organic carbon testing, characterized by: The invention comprises a liquid loading device and a reaction device, wherein the liquid loading device comprises a movable liquid injection component, an acid injection passage and a water injection passage, wherein the movable liquid injection component has a first liquid injection port and a second liquid injection port, wherein a pipeline of the acid injection passage is connected to the first liquid injection port, and a pipeline of the water injection passage is connected to the second liquid injection port, wherein the reaction device comprises a reaction container for holding rock samples, wherein the movable liquid injection component is located above the reaction device and can be moved along the arrangement direction of the reaction container so that the first liquid injection port and the second liquid injection port are aligned with the reaction container, wherein the liquid loading device provides the acid injection passage and the water injection passage which are independent of each other; and further comprises a liquid discharge device, wherein the liquid discharge device comprises a negative pressure component, wherein the reaction device further comprises a fixed tank and a filtrate bin, wherein the reaction container is installed in the fixed tank, wherein the fixed tank is arranged in the filtrate bin, and a through hole is provided at the bottom of the fixed tank, wherein the reaction The bottom wall of the container is connected with the filtrate bin through the through hole, the opening of the reaction container is connected with the filtrate bin through a first sealing member, and a second sealing member is provided between the bottom wall of the reaction container and the fixed groove; the negative pressure assembly is connected with the filtrate bin, and a drainage rod is also provided at the through hole of the fixed groove; the first sealing member comprises a first sealing gasket, a pressing plate and a locking member, the first sealing gasket is laid on the opening of the reaction container and the notch of the fixed groove, the pressing plate is pressed on the first sealing gasket, and the pressing plate and the filtrate bin are fixedly connected through the locking member; the second sealing member comprises a second sealing gasket and a washer, the second sealing gasket is provided at the bottom of the fixed groove, the reaction container is placed on the second sealing gasket, the gasket is located between the reaction container and the second sealing gasket, and the bottom surface of the second sealing gasket in contact with the gasket is an inclined surface which gradually tilts downward from the outside to the center.

2. The pretreatment system for rock total organic carbon testing according to claim 1, characterized in that: The mobile liquid injection assembly is also provided with a CO2 detector, which is located above the reaction device and directly faces the reaction container.

3. The pretreatment system for rock total organic carbon testing according to claim 2, characterized in that: The reaction device further comprises a heating assembly, wherein the heating assembly comprises a heating component and a circulating air port, the heating component is communicated with the filtrate bin via the circulating air port, and a temperature detector is also arranged in the filtrate bin.

4. The pretreatment system for rock total organic carbon testing according to claim 1, characterized in that: The drainage device includes a filtrate collecting tank, an ion detector and a waste liquid collecting tank. The filtrate collecting tank is connected to the bottom of the filtrate bin through a pipeline, a pump body is provided on the pipeline, and the ion detector is arranged above the filtrate collecting tank through a lifting assembly. The filtrate collecting tank is connected to the waste liquid collecting tank.

5. The pretreatment system for rock total organic carbon testing according to claim 3, characterized in that: The mobile liquid injection assembly includes a robotic arm and a guide rail, the guide rail is extended along the arrangement direction of the reaction containers, the robotic arm is connected to the guide rail and can move along the guide rail, and the first liquid injection port, the second liquid injection port and the CO2 detector are all arranged on the robotic arm.

6. The pretreatment system for rock total organic carbon testing according to claim 1, characterized in that: The acid injection passage includes an acid reagent bottle and a first injection pump, the first injection pump is connected to the acid reagent bottle through a first valve body, and the first injection pump is also connected to the first injection port through a pipeline. The water injection passage includes a water reagent bottle and a second injection pump, the second injection pump is connected to the water reagent bottle through a second valve body, and the second injection pump is also connected to the second injection port through a pipeline.

7. The pretreatment system for rock total organic carbon testing according to claim 1, characterized in that: It also includes a control device, which is used to control the operation of the liquid material loading device, the reaction device, and the liquid discharge device.

8. A pretreatment method for testing total organic carbon in rocks, characterized in that: The pretreatment system for rock total organic carbon testing according to any one of claims 1 to 7 comprises: (1) Sample dissolution: The acid reagent is injected into the crucible containing the rock sample by moving the liquid injection component to drive the acid injection passage to move; The crucible is heated by a heating component until the temperature in the filtrate chamber reaches a preset sample dissolving temperature; The CO2 detector is driven to move by the mobile liquid injection component to detect the CO2 gas concentration above the crucible. If the CO2 gas concentration is greater than the set CO2 gas concentration threshold, acid is injected into the reaction container again until the CO2 gas concentration above all crucibles is less than or equal to the set CO2 gas concentration threshold; (2) Washing sample: After the sample dissolution process is completed, the water injection passage is driven to move by the moving liquid injection assembly to inject distilled water into the crucible containing the rock sample; The negative pressure component forms a negative pressure in the filtrate bin, and the filtrate flows into the filtrate collection tank; The ion concentration of the filtrate in the filtrate collection tank is detected by an ion detector. If the ion concentration is greater than the set ion concentration threshold, distilled water is injected into the reaction container again until the ion concentration of the filtrate is less than or equal to the set ion concentration threshold; The filtrate from the filtrate collection tank is discharged into the waste liquid collection tank; (3) Sample drying: After the sample washing process is completed, the crucible is heated again by the heating component, and the rock sample is dried at a preset drying temperature until the rock sample is completely dry.

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