Full-automatic online continuous sampling system and sampling method

Abstract

The invention provides a full-automatic online continuous sampling system and method. The system comprises a high-pressure reaction kettle subsystem and a full-automatic continuous sampling subsystem, and the full-automatic continuous sampling subsystem comprises a six-way switching valve B, a six-way switching valve A, a sample test tube turntable and a PLC (Programmable Logic Controller); one end of the six-way switching valve B is connected with the low-pressure purging gas path, and the other end is connected with the sample test tube turntable, so that a low-pressure purging unit is formed; one end of the six-way switching valve A is connected with the high-pressure purging gas path, and the other end of the six-way switching valve A is connected with the high-pressure reaction kettle, so that a high-pressure purging unit is formed; the method comprises the following steps: carrying out low-pressure purging before sampling; sampling to obtain a sample quantitative loop; sampling a sample test tube; high-pressure purging is realized after sampling; resetting after sampling; pLC programming realizes unmanned operation and repeated continuous sampling. By adopting the unique design of combining the high-pressure purging unit and the low-pressure purging unit, the problem that the accuracy is influenced by residual liquid is solved. And performance reduction or failure of the sealing material caused by high temperature is avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-temperature and high-pressure reaction kettles, and particularly relates to a full-automatic online continuous sampling system and a sampling method. BACKGROUND

[0002] A high-temperature and high-pressure reaction kettle is a commonly used reaction device in the chemical industry. During the reaction process, periodic and timed sampling and analysis of liquid-phase products are important means for monitoring and controlling the reaction process. However, under high-temperature and high-pressure conditions, especially in heavy oil hydrogenation reactions, the temperature and pressure can reach 400℃ and 30MPa. To ensure the safety of operating personnel, it is necessary to replace manual sampling with full-automatic sampling.

[0003] The main difficulties in achieving full-automatic online continuous sampling are as follows:

[0004] 1. Residual liquid affecting accuracy: After each sampling, some liquid will be left in the high-pressure reaction kettle and the sampling pipeline outside the kettle. If not effectively removed, the residual liquid will mix into the sample taken next time, resulting in distorted subsequent sampling results.

[0005] 2. Difficulties in processing high-temperature samples: Processing high-temperature samples (such as above 200℃) is challenging. For example, patent CN118731401A discloses a scheme for sampling high-temperature samples using a six-way switching valve. However, the sealing packing of the valve (mostly made of PTFE material) will significantly decrease in sealing performance or even fail at high temperatures above 200℃, posing a risk of leakage and safety hazards to the system. SUMMARY

[0006] The present application proposes a full-automatic online continuous sampling system and a sampling method to solve the problems existing in the prior art. The first purpose is to solve the problem of residual liquid affecting accuracy in achieving full-automatic online continuous sampling, and the second purpose is to solve the problem of difficulties in processing high-temperature samples in achieving full-automatic online continuous sampling.

[0007] The present application adopts the following technical solutions to solve the technical problems:

[0008] The application relates to a full-automatic online continuous sampling system, which comprises a high-pressure reaction kettle subsystem and a full-automatic continuous sampling subsystem, and has the characteristics that the full-automatic continuous sampling subsystem comprises a six-way switching valve B, a six-way switching valve A, a sample test tube rotating disc and a PLC controller; one end of the six-way switching valve B is connected with a low-pressure purging gas path, and the other end is connected with the sample test tube rotating disc, so as to form a low-pressure purging unit of the full-automatic continuous sampling system; one end of the six-way switching valve A is connected with a high-pressure purging gas path, and the other end is connected with the high-pressure reaction kettle, so as to form a high-pressure purging unit of the full-automatic continuous sampling system; the low-pressure purging unit is used for purging residual liquid in a sample quantitative ring after the last sampling to a sample test tube of the sample test tube rotating disc before sampling; the high-pressure purging unit is used for back purging residual liquid in a bottom sampling tube after the last sampling to the high-pressure reaction kettle of the high-pressure reaction kettle subsystem; and the bottom sampling tube is arranged in the high-pressure reaction kettle of the high-pressure reaction kettle subsystem.

[0009] Further, the high-pressure reaction kettle subsystem comprises a high-pressure reaction kettle, a bottom sampling tube in the high-pressure reaction kettle and a cooling system; the bottom sampling tube is inserted into liquid, so that liquid phase can be pressed out when there is a pressure difference between inside and outside of the kettle; after the bottom sampling tube comes out of the kettle, the outlet of the bottom sampling tube is connected with the cooling system, so that high-temperature liquid can be instantaneously cooled after coming out; the cooling system is composed of a cooling water jacket and a low-temperature circulator; the cooling water jacket is sleeved on the outlet pipeline of the bottom sampling tube; and the low-temperature circulator is responsible for cooling and circulating refrigerant into the cooling water jacket to realize cooling.

[0010] Further, the six-way switching valve A has six ports, which are A1, A2, A3, A4, A5 and A6; the six-way switching valve B has six ports, which are B1, B2, B3, B4, B5 and B6; B1 is connected with A1, and a check valve is arranged in the middle, so that medium can only flow from A1 to B1, and vice versa.

[0011] Further, a nitrogen cylinder and a high-pressure pressure stabilizing valve are arranged on the high-pressure purging gas path; the low-pressure purging gas path comprises a nitrogen cylinder, a low-pressure pressure stabilizing valve and a pneumatic ball valve; the high-pressure purging gas path and the low-pressure purging gas path share the nitrogen cylinder; the high-pressure pressure stabilizing valve and the low-pressure pressure stabilizing valve are controlled and pressure-regulated by the PLC controller, and the pressure of the high-pressure gas path is adjusted according to needs; and the pneumatic ball valve is opened and closed by the PLC control.

[0012] Further, the PLC controller controls the valve core of the six-way switching valve B and the six-way switching valve A to rotate by 60 degrees, so as to realize two-by-two connection between different ports of the six-way switching valve B and the six-way switching valve A.

[0013] Further, B2 on the six-way switching valve B is connected with the bottom sampling pipe of the high-pressure reactor unit; a sample quantitative ring is arranged between B3 and B6; B4 is connected to the sample test tube turntable; B5 is connected to the nitrogen cylinder through the pneumatic ball valve and the low-pressure stabilizing valve on the low-pressure purge gas path to receive the low-pressure purge gas;

[0014] A2 and A4 on the six-way switching valve A are closed; A3 is connected with A6, and a high-pressure quantitative tank is arranged in the middle, which is used for temporarily storing the high-pressure nitrogen gas back-flushed into the reactor; the volume of the high-pressure quantitative tank is set according to the volume of the sample quantitative ring to ensure that the gas back-flushed into the reactor can compensate the pressure lost when the sample is taken out to balance; A5 is connected with the nitrogen cylinder through the high-pressure stabilizing valve to receive the high-pressure purge gas; the high-pressure stabilizing valve is controlled by the PLC to adjust the pressure, and the pressure of the high-pressure gas path is adjusted according to the pressure of the high-temperature and high-pressure reactor to make the pressure greater than the pressure in the high-temperature and high-pressure reactor by 0.5 MPa, so that the back-flushing function can be realized.

[0015] An automatic online continuous sampling method, which has the following steps:

[0016] Step one: low-pressure purge before sampling to ensure that the pipeline is free of water and oxygen;

[0017] Step two: sampling to the sample quantitative ring after purging;

[0018] Step three: sampling from the sample quantitative ring to the sample test tube;

[0019] Step four: high-pressure purge after sampling;

[0020] Step five: reset after sampling;

[0021] Step six: the PLC programs the repeated actions according to the sampling times and time to realize unattended and multiple continuous sampling.

[0022] The low-pressure purge before sampling in step one ensures that the pipeline is free of water and oxygen, and the specific steps are as follows:

[0023] 1) B1 and B2 of the six-way switching valve B are connected, B3 and B4 are connected, and B5 and B6 are connected;

[0024] 2) the pressure of the low-pressure stabilizing valve on the low-pressure purge gas path is adjusted to 0.5 MPa by the PLC controller, and then the pneumatic ball valve is opened to purge for about 5 minutes, at which time the low-pressure purge gas path is connected to the sample quantitative ring and the sample test tube to realize the water-free and oxygen-free state;

[0025] 3) the pneumatic ball valve is closed after purging is completed;

[0026] The specific steps of sampling to the sample quantitative ring after purging in step two are as follows:

[0027] 1) When the purging is completed, the low-temperature circulator is opened in advance to cool the cooling water jacket by the PLC controller, and the temperature is adjusted according to the characteristics of the reaction material and controlled between 20-80 degrees;

[0028] 2) When the refrigerant temperature reaches the set temperature, the six-way valve B is switched by the PLC controller to rotate 60 degrees, to realize the connection of B2 and B3, the connection of B4 and B5, and the connection of B6 and B1.

[0029] 3) Due to the pressure difference between the inside and outside of the kettle, the liquid sample is pressed out through the bottom sampling tube in the kettle, and after instantaneous cooling, it is temporarily stored in the sample quantitative ring; at the same time, the pressure of the high-pressure pressure stabilizing valve is adjusted to be 0.5 MPa higher than the pressure in the high-temperature and high-pressure kettle, so that the high-pressure nitrogen gas is also temporarily stored in the high-pressure quantitative tank for use.

[0030] The third step of taking sample from the sample quantitative ring to the sample test tube is as follows:

[0031] 1) Switch the six-way switch valve B back to rotate 60 degrees to reset and return to the purging state again, at this time B1 and B2 are connected, B3 and B4 are connected, and B5 and B6 are connected.

[0032] 2) The liquid sample in the sample quantitative ring flows into the sample test tube, and then the pneumatic ball valve is opened to continue purging for about 1 minute.

[0033] 3) When the residual liquid in the sample quantitative ring is purged clean, the pneumatic ball valve is closed.

[0034] The fourth step of taking sample and realizing high-pressure purging is as follows:

[0035] 1) Switch the six-way switch valve A to rotate 60 degrees to connect A2 and A3, A4 and A5, and A6 and A1.

[0036] 2) The high-pressure gas stored in the high-pressure quantitative tank is back-flushed into the kettle through the one-way valve, B1 and B2, to realize the purging of the bottom sampling tube, and at the same time, the pressure lost in the kettle during sampling is compensated to achieve pressure balance without affecting the continuous reaction.

[0037] The fifth step of taking sample and resetting is as follows:

[0038] When a sampling and back-flushing process is completed, the six-way switch valve A is rotated back 60 degrees to connect A1 and A2, A3 and A4, and A5 and A6 to reset, and at the same time, the sample test tube rotating disc is rotated to prepare the second test tube for the next sampling.

[0039] Advantages and effects of the present application

[0040] 1. The application adopts the unique design of combining high-pressure purging unit and low-pressure purging unit, connects the high-pressure purging gas path through six-way switching valve A, reversely blows the residual liquid in the plug bottom sampling pipe with high pressure, blows it back into the high-pressure reaction kettle, connects the low-pressure purging gas path through six-way switching valve B, and blows the residual liquid in the sample quantitative ring into the sample test tube of the sample test tube carousel with low pressure. The residual liquid in the sampling pipeline (plug bottom sampling pipe and sample quantitative ring) is effectively removed, the residual liquid is prevented from mixing into the next sample taken, the accuracy and reliability of the sampling result are ensured, and the problem of residual liquid affecting accuracy is solved.

[0041] 2. The application instantaneously cools the high-temperature sample through the cooling system, connects the cooling system at the outlet of the plug bottom sampling pipe, and realizes efficient and continuous cooling by circulating the coolant into the cooling water jacket through the low-temperature circulator, thereby reducing the thermal influence of the high-temperature sample on the sealing material of the downstream six-way switching valve, avoiding the performance degradation or failure of the sealing material due to high temperature, reducing the leakage risk of the system due to sealing failure, and improving the safety of the entire sampling system. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The six-way switching valve state diagram when the application is purged with nitrogen;

[0043] Figure 2 The six-way switching valve state diagram when the application samples into the sample quantitative ring;

[0044] Figure 3 The six-way switching valve state diagram when the application samples into the sample test tube;

[0045] Figure 4 The six-way switching valve state diagram when the application is high-pressure backblown

[0046] Figure 5 The six-way switching valve and sample test tube carousel state diagram when the application is reset. DETAILED DESCRIPTION

[0047] Innovations of the application

[0048] 1. Double-stage target purging residual elimination technology: ① The high-pressure backblowing system uses high-pressure gas to accurately backblow the residual liquid in the plug bottom sampling pipe to the reaction kettle, eliminating the residual liquid in the plug bottom sampling pipe. ② The low-pressure displacement system blows clean nitrogen gas to the sample quantitative ring to realize complete displacement of the residual liquid, ensuring that the sampling is not cross-contaminated. ③ The double-system layered operation solves the problems of pipeline retention and quantitative ring residual, and the precision is improved to within ±0.5%.

[0049] 2. Micro-channel cooling technology: ①Integrating high-efficiency cooling modules, achieving millisecond-level temperature reduction when high-temperature samples > 200℃ flow through the sampling ring, avoiding denaturation of heat-sensitive substances. ②Synchronously protecting the sealing material of the six-way valve, prolonging the service life of the key components and reducing the risk of valve body failure caused by high temperature.

[0050] 3. Pressure self-balancing technology: ①High-pressure quantitative tank and reaction kettle pressure interlocking: automatically triggering pressure compensation when sampling, injecting high-pressure inert gas into the kettle to instantaneously balance the pressure loss caused by sampling;

[0051] 4. Anhydrous and anaerobic closed-loop control: full-pipeline nitrogen positive pressure protection: inert gas covers the whole process from the gas source to the sampling outlet, combined with one-way valves (such as B1-A1 circuit) to prevent gas backflow, ensuring that the sample transfer is isolated from water and oxygen throughout the process.

[0052] 5. Dual-valve time-space collaborative control: ①Six-way valve time sequence linkage: through PLC programming to realize the cooperation of six-way switch valve A (high-pressure purging / sampling switching) and six-way switch valve B (low-pressure purging / quantitative reset). ②One-way flow forced path design: the one-way valve between B1-A1 builds an irreversible flow path, eliminating backflow pollution caused by pressure disturbance.

[0053] Summary: Through the coupling of five technologies: dual-stage targeted purging, micro-channel cooling technology, pressure self-balancing, anhydrous and anaerobic closed-loop control, and dual-valve time-space collaborative control, the five core pain points of high-temperature and high-pressure system residue control (precision), sample integrity (temperature), system stability (pressure), environmental sensitivity (water and oxygen), and operation continuity (automation) are overcome, realizing continuous and precise sampling without human intervention.

[0054] Design principle of the present application

[0055] 1. Active removal of residue: ① Use high-pressure backflushing to remove residue from the source insertion bottom tube; use precisely controlled low-pressure purging to remove residue on the sample quantification ring, and ensure the effectiveness of the path through the one-way valve to form a two-stage purging system. Specifically: high-pressure gas passes through six-way switching valve A and reversely blows into the insertion bottom sampling tube of the high-pressure reaction kettle along the path opposite to sampling, so that the high-pressure gas flow completely pushes the residual sample liquid adhering to the inner wall and dead angle of the sampling tube back to the reaction kettle body. The design of the high-pressure quantification tank ensures that there is enough volume and pressure of gas for effective backflushing, overcoming the pressure resistance in the kettle. ② Low-pressure purging to remove residue on the quantification ring: after the sample is transferred from the quantification ring to the sample test tube, the system controls six-way switching valve B to switch to the purging station and access the low-pressure purging gas path (usually low-pressure nitrogen). The low-pressure gas flows through the sample quantification ring and its connecting pipeline. The gas flow completely purges the residual sample liquid remaining in the quantification ring channel and pipe wall and carries it to the downstream sample test tube for collection, ensuring the cleanliness of the quantification ring and the accuracy of the next sampling. ③ Key support: one-way valves are provided in the high-pressure and low-pressure purging circuits to strictly prevent gas backflow, ensuring the uniqueness and effectiveness of the purging path. ④ Precise gas pressure control: the gas source from the nitrogen cylinder is precisely and stably regulated by high-pressure and low-pressure pressure stabilizing valves. The PLC controller can be programmed to set and monitor the pressure value in real time, ensuring that the high-pressure backflushing has enough power to overcome the kettle pressure. ⑤ Pressure balance compensation: the volume of the high-pressure quantification tank is carefully designed and calculated. When high-pressure backflushing is performed, the volume of the gas backflushed into the kettle not only removes the residual liquid, but also basically compensates for the volume (or pressure) of the gas lost in the kettle due to sampling, helping to maintain the stability of the reaction system pressure and reducing the pressure imbalance caused by sampling.

[0056] 2. Rapid cooling of the source: immediately after the sample leaves the reaction kettle, forced cooling is performed to protect the subsequent fragile valve and seal, ensuring sample stability and system reliability. Specifically: ① Set an active cooling device near the outlet of the insertion bottom sampling tube, which is the first passageway for high-temperature material leaving the reaction kettle and entering the sampling system. Use a cooling water jacket to wrap the key pipeline nodes through which the high-temperature sample flows, and use a low-temperature circulator to provide stable and controllable temperature coolant; ② Achieve rapid cooling: the high-temperature sample liquid is cooled to a safe temperature range that the subsequent pipeline, six-way switching valves A / B and quantification ring can withstand within a very short time. ③ Effectively prevent high temperature from causing seal aging, failure and leakage, protect the internal structure of the precision valve from heat deformation or damage, and prolong the service life of the equipment.

[0057] 3. Intelligent process control: rely on PLC controller to realize all valve switching, gas pressure regulation automation, and support user-defined continuous, repeated sampling strategy through programmable logic. Specifically: ① PLC accurately controls the rotation or switching action of six-way switching valve A and B, realizes the automatic switching of different process stages such as sampling, high-pressure back flushing, low-pressure purging, and resetting. PLC controls the opening and closing of high-pressure and low-pressure stabilizing valves according to the preset program or feedback signal, and accurately adjusts the pressure of the purging gas. ②Unattended: once the program is started, the system can run automatically for a set time (several hours to several days) without human intervention to complete multiple continuous sampling.

[0058] Based on the above principles, a fully automatic online continuous sampling system, as shown in Figures 1-5 , includes a high-pressure reactor subsystem and a fully automatic continuous sampling subsystem, which is characterized by: the fully automatic continuous sampling subsystem includes six-way switching valve B, six-way switching valve A, sample tube carousel, PLC controller; one end of six-way switching valve B is connected to the low-pressure purging gas path, and the other end is connected to the sample tube carousel, thereby forming a low-pressure purging unit of the fully automatic continuous sampling system; one end of six-way switching valve A is connected to the high-pressure purging gas path, and the other end is connected to the high-pressure reactor, thereby forming a high-pressure purging unit of the fully automatic continuous sampling system, the low-pressure purging unit is used to purge the residual liquid in the sample quantitative ring after the last sampling to the sample tube of the sample tube carousel; the high-pressure purging unit is used to back flush the residual liquid in the bottom sampling tube to the high-pressure reactor of the high-pressure reactor subsystem after the last sampling; the bottom sampling tube is arranged in the high-pressure reactor of the high-pressure reactor subsystem.

[0059] As shown in Figures 1-5 , the high-pressure reactor subsystem includes a high-pressure reactor, a bottom sampling tube in the high-pressure reactor, and a cooling system; the bottom sampling tube is inserted into the liquid to ensure that the liquid phase can be pressed out when there is a pressure difference between the inside and outside of the reactor; the outlet of the bottom sampling tube after coming out of the reactor is connected to the cooling system to ensure that the high-temperature liquid can be cooled instantly after coming out, the cooling system is composed of a cooling water jacket and a low-temperature circulator, the cooling water jacket is sleeved on the outlet pipeline of the bottom sampling tube, and the low-temperature circulator is responsible for cooling and circulating the coolant to the cooling water jacket to achieve cooling.

[0060] As shown in Figures 1-5 , six-way switching valve A has six ports, A1, A2, A3, A4, A5, and A6; six-way switching valve B has six ports, B1, B2, B3, B4, B5, and B6; B1 is connected to A1 with a check valve in between to ensure that the medium can only flow from A1 to B1, and vice versa.

[0061] As shown in Figures 1-5As shown, the high-pressure purge gas path is provided with a nitrogen cylinder and a high-pressure pressure stabilizing valve; the low-pressure purge gas path includes a nitrogen cylinder, a low-pressure pressure stabilizing valve and a pneumatic ball valve, and the high-pressure purge gas path and the low-pressure purge gas path share the nitrogen cylinder; the high-pressure pressure stabilizing valve and the low-pressure pressure stabilizing valve are controlled by a PLC controller to adjust the pressure of the high-pressure gas path as needed; and the pneumatic ball valve is controlled to open and close by the PLC.

[0062] As shown in Figures 1-5 , the PLC controller controls the valve core of the six-way switching valve B and the six-way switching valve A to rotate by 60 degrees, respectively, to realize the two-by-two communication between different ports of the six-way switching valve B and the six-way switching valve A.

[0063] As shown in Figures 1-5 , B2 on the six-way switching valve B is connected with a bottom sampling pipe of the high-pressure reaction kettle unit; a sample quantitative ring is arranged between B3 and B6; B4 is connected to a sample test tube turntable; B5 is connected to the nitrogen cylinder through the pneumatic ball valve and the low-pressure pressure stabilizing valve on the low-pressure purge gas path to receive low-pressure purge gas.

[0064] The A2 and A4 ports on the six-way switching valve A are closed; A3 is connected with A6, and a high-pressure quantitative tank is arranged in the middle to temporarily store high-pressure nitrogen gas for back blowing into the kettle; the volume of the high-pressure quantitative tank is set according to the volume of the sample quantitative ring to ensure that the back blowing gas into the kettle can compensate for the pressure lost when the sample is taken out to balance; A5 is connected with the nitrogen cylinder through the high-pressure pressure stabilizing valve to receive high-pressure purge gas, and the high-pressure pressure stabilizing valve is controlled by the PLC to adjust the pressure of the high-pressure gas path according to the pressure of the high-temperature and high-pressure kettle, so that the pressure is greater than the pressure in the high-temperature and high-pressure kettle by 0.5 MPa, thereby realizing the back blowing function.

[0065] An automatic online continuous sampling method, characterized by comprising the following steps:

[0066] Step one, low-pressure purge before sampling to ensure that the pipeline is free of water and oxygen;

[0067] Step two, sampling to the sample quantitative ring after purging;

[0068] Step three, sampling from the sample quantitative ring to the sample test tube;

[0069] Step four, high-pressure purge after sampling;

[0070] Step five, reset after sampling;

[0071] Step six, the PLC programs the repeated actions according to the sampling frequency and time to realize unattended and multiple continuous sampling.

[0072] As shown in Figure 1 , the step one is to perform low-pressure purge before sampling to ensure that the pipeline is free of water and oxygen, and the specific steps are as follows:

[0073] 1) six-way switch valve B B1 and B2, B3 and B4, B5 and B6 are connected;

[0074] 2) through the PLC controller to adjust the low pressure blow-by gas path on the low pressure stabilizing valve pressure to 0.5 MPa, and then open the pneumatic ball valve, blow-by for about 5 minutes, at this time the low pressure blow-by gas path to the sample quantitative ring and sample test tube, to achieve the state of no water and no oxygen;

[0075] 3) blow-by is completed, the pneumatic ball valve is closed;

[0076] As shown in Figure 2 , the sample is taken to the sample quantitative ring after the step two blow-by, and the specific steps are as follows:

[0077] 1) when the blow-by is completed, the low temperature circulator is opened in advance to cool the cooling water jacket through the PLC controller, and the temperature is adjusted according to the characteristics of the reactant, which can be controlled between 20-80 degrees;

[0078] 2) when the refrigerant temperature reaches the set temperature, switch the six-way valve B by 60 degrees through the PLC controller, so that B2 and B3 are connected, B4 and B5 are connected, and B6 and B1 are connected;

[0079] 3) due to the pressure difference between the kettle and the kettle, the liquid sample is pressed out through the kettle bottom sampling tube, and then stored in the sample quantitative ring after instantaneous cooling; at the same time, the pressure of the high pressure stabilizing valve is adjusted to be greater than the pressure in the high temperature and high pressure kettle by 0.5 MPa, so that the high pressure nitrogen gas is also temporarily stored in the high pressure quantitative tank for use.

[0080] As shown in Figure 3 , the sample is taken to the sample test tube from the sample quantitative ring in the step three, and the specific steps are as follows:

[0081] 1) switch the six-way switch valve B back to rotate 60 degrees to reset and return to the blow-by state again, at this time B1 and B2 are connected, B3 and B4 are connected, and B5 and B6 are connected;

[0082] 2) the liquid sample in the sample quantitative ring flows into the sample test tube, and then the pneumatic ball valve is opened to allow the low pressure blow-by gas to continue to blow-by for about 1 minute;

[0083] 3) when the residual liquid in the sample quantitative ring is blown clean, the pneumatic ball valve is closed.

[0084] As shown in Figure 4 , the high pressure blow-by is realized after the sample is taken in the step four, and the specific steps are as follows:

[0085] 1) switch the six-way switch valve A by 60 degrees to connect A2 and A3, A4 and A5, and A6 and A1;

[0086] 2) high pressure gas stored in high pressure quantitative tank is back-flushed into the kettle through one-way valve, B1 and B2, to realize the purging of the sampling tube with bottom plug, and to compensate the pressure loss in the kettle due to sampling, so as to achieve pressure balance without affecting the continuous reaction;

[0087] As shown in Figure 5 the fifth step is resetting after sampling, and the specific process is as follows:

[0088] After one sampling and back-flushing process is completed, the six-way switching valve A is rotated back by 60 degrees to connect A1 and A2, connect A3 and A4, and connect A5 and A6 to reset, and the sample tube rotating disc is rotated to prepare the second tube for the next sampling.

[0089] It should be emphasized that the above specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the above embodiments without creative contribution after reading the present specification, but as long as it is within the scope of the claims of the present application, it is protected.

Claims

1. A fully automatic on-line continuous sampling system, comprising a high-pressure reactor subsystem, and a fully automatic continuous sampling subsystem, characterized in that: The automatic continuous sample taking system comprises a six-way switching valve B, a six-way switching valve A, a sample test tube turntable and a PLC controller; one end of the six-way switching valve B is connected with a low-pressure purging gas path, and the other end is connected with the sample test tube turntable, thereby forming a low-pressure purging unit of the automatic continuous sample taking system; one end of the six-way switching valve A is connected with a high-pressure purging gas path, and the other end is connected with a high-pressure reaction kettle, thereby forming a high-pressure purging unit of the automatic continuous sample taking system; the low-pressure purging unit is used for purging residual liquid in a sample quantitative ring after last sampling to a sample test tube of the sample test tube turntable before sampling; the high-pressure purging unit is used for back purging residual liquid in a bottom sampling tube after last sampling to the high-pressure reaction kettle of the high-pressure reaction kettle subsystem; the bottom sampling tube is arranged in the high-pressure reaction kettle of the high-pressure reaction kettle subsystem.

2. The fully automatic on-line continuous sampling system according to claim 1, characterized in that: The high-pressure reaction kettle subsystem comprises a high-pressure reaction kettle, a bottom sampling tube in the high-pressure reaction kettle and a cooling system; the bottom sampling tube is inserted into liquid to ensure that liquid phase can be pressed out when there is a pressure difference between inside and outside of the kettle; after the bottom sampling tube comes out of the kettle, the outlet thereof is connected with the cooling system to ensure that high-temperature liquid can be instantaneously cooled after coming out; the cooling system is composed of a cooling water jacket and a low-temperature circulator; the cooling water jacket is sleeved on the outlet pipeline of the bottom sampling tube; the low-temperature circulator is responsible for cooling and circulating coolant into the cooling water jacket to realize cooling.

3. The fully automatic on-line continuous sampling system according to claim 1, characterized in that: The six-way switching valve A has six ports, namely A1, A2, A3, A4, A5 and A6; the six-way switching valve B has six ports, namely B1, B2, B3, B4, B5 and B6; B1 is connected with A1, and a check valve is arranged therebetween to ensure that medium can only flow from A1 to B1, and vice versa.

4. The fully automatic on-line continuous sampling system according to claim 1, characterized in that: A nitrogen cylinder and a high-pressure pressure stabilizing valve are arranged on the high-pressure purging gas path; the low-pressure purging gas path comprises a nitrogen cylinder, a low-pressure pressure stabilizing valve and a pneumatic ball valve; the high-pressure purging gas path and the low-pressure purging gas path share the nitrogen cylinder; the high-pressure pressure stabilizing valve and the low-pressure pressure stabilizing valve are controlled to adjust pressure by the PLC controller according to needs; and the pneumatic ball valve is controlled to open and close by the PLC.

5. The fully automatic on-line continuous sampling system according to claim 1, characterized in that: The PLC controller controls the valve core of the six-way switching valve B and the six-way switching valve A to rotate by an angle of 60 degrees to realize two-by-two communication between different ports of the six-way switching valve B and the six-way switching valve A.

6. The fully automatic on-line continuous sampling system according to claim 3, characterized in that: B2 on the six-way switching valve B is connected with the bottom sampling tube of the high-pressure reaction kettle unit; B3 and B6 are provided with a sample quantitative ring; B4 is connected with the sample test tube turntable; B5 is connected with the nitrogen cylinder through the pneumatic ball valve and the low-pressure pressure stabilizing valve on the low-pressure purging gas path to receive low-pressure purging gas.

7. The fully automatic on-line continuous sampling system according to claim 3, characterized in that: A2 and A4 ports of six-way switch valve A are closed; A3 is connected with A6, and a high-pressure constant-volume tank is arranged in the middle, which is used for temporarily storing high-pressure nitrogen gas backblown into the kettle. The volume of the high-pressure constant-volume tank is set according to the volume of the sample constant-volume ring, so as to ensure that the gas backblown into the kettle can compensate the pressure lost when the sample is taken out to balance; A5 is connected with a nitrogen gas cylinder through a high-pressure pressure stabilizing valve, receives high-pressure purge gas, and the high-pressure pressure stabilizing valve is controlled by PLC to adjust the pressure, adjusts the pressure of the high-pressure gas path according to the pressure of the high-temperature and high-pressure kettle, and makes the pressure greater than the pressure in the high-temperature and high-pressure kettle by 0.5 MPa, so that the backblowing function can be realized.

8. A fully automatic on-line continuous sampling method based on the fully automatic on-line continuous sampling system according to any one of claims 1-8, characterized in that: The method comprises the following steps: Step one: low-pressure purging before sampling to ensure that there is no water and oxygen in the pipeline; Step two: sampling into the sample constant-volume ring after purging; Step three: sampling from the sample constant-volume ring into the sample test tube; Step four: high-pressure purging after sampling; Step five: resetting after sampling; Step six: the PLC programs the repeated actions according to the sampling frequency and time to realize unmanned operation and continuous sampling for multiple times.

9. The fully automatic online continuous sampling method according to claim 8, characterized in that: The step one is low-pressure purging before sampling to ensure that there is no water and oxygen in the pipeline, and the specific steps are as follows: 1) B1 and B2 of six-way switch valve B are connected, B3 and B4 are connected, and B5 and B6 are connected; 2) the pressure of the low-pressure pressure stabilizing valve on the low-pressure purging gas path is adjusted to 0.5 MPa by the PLC controller, and then the pneumatic ball valve is opened, and purging is performed for about 5 minutes. At this time, the low-pressure purging gas path reaches the sample constant-volume ring and the sample test tube, and the water and oxygen free state is realized; 3) the pneumatic ball valve is closed after purging is completed; The step two is sampling into the sample constant-volume ring after purging, and the specific steps are as follows: 1) when purging is completed, the low-temperature circulator is opened in advance to cool the cooling water jacket by the PLC controller, and the temperature is adjusted according to the characteristics of the reaction material, and the temperature is controlled between 20-80 degrees; 2) when the temperature of the refrigerant reaches the set temperature, the six-way valve B is switched by 60 degrees by the PLC controller, so that B2 and B3 are connected, B4 and B5 are connected, and B6 and B1 are connected; 3) due to the pressure difference between the kettle and the outside, the liquid sample is pressed out through the bottom sampling tube in the kettle, and then stored in the sample constant-volume ring after instantaneous cooling; at the same time, the pressure of the high-pressure pressure stabilizing valve is adjusted, so that the pressure is greater than the pressure in the high-temperature and high-pressure kettle by 0.5 MPa, so that the high-pressure nitrogen gas is also temporarily stored in the high-pressure constant-volume tank for use; The step three is sampling from the sample constant-volume ring into the sample test tube, and the specific steps are as follows: 1) the six-way switch valve B is switched back by 60 degrees to reset and return to the purging state again, at this time, B1 and B2 are connected, B3 and B4 are connected, and B5 and B6 are connected; 2) the liquid sample in the sample constant-volume ring flows into the sample test tube, and then the pneumatic ball valve is opened to continue purging for about 1 minute; 3) when the residual liquid in the sample constant-volume ring is purged clean, the pneumatic ball valve is closed; The step four is high-pressure purging after sampling, and the specific steps are as follows: 1) the six-way switch valve A is switched by 60 degrees to connect A2 and A3, A4 and A5, and A6 and A1; 2) the six-way switch valve A is switched by 60 degrees to connect A2 and A3, A4 and A5, and A6 and A1; 2) high-pressure gas stored in high-pressure quantitative tank is back-flushed into the kettle through one-way valve, B1 and B2, to realize the purging of the sampling tube with bottom plug, and to compensate the pressure loss in the kettle due to sampling, so as to achieve pressure balance without affecting the continuous reaction; The step five is resetting after sampling, and the details are as follows: After the completion of a sampling and back-flushing process, the six-way switching valve A is rotated back by 60 degrees, A1 and A2 are connected, A3 and A4 are connected, A5 and A6 are connected, and the second test tube is rotated to prepare for the next sampling.

Images