An on-line gas chromatographic analysis and detection device for continuously producing high-purity piperazine

Abstract

The utility model relates to compound test technical field discloses a kind of on-line gas chromatogram analysis detection device of continuous production high-purity piperazine, rectifying column side line outlet is divided into two ways after being connected with sampling loop pipeline, one way is connected with rectifying column side line entrance after passing through first switch valve, another way is connected with shunt sample injector after passing through sample switch valve, filter, backflush valve, automatic sample valve, liquid quantitative ring, sixth switch valve, vaporizing chamber, six-way valve;Six interfaces of six-way valve are respectively connected with the outlet of vaporizing chamber, the import and export of gas quantitative ring, second N2 carrier gas pipeline, the inlet of check valve and the inlet of shunt sample injector.The utility model can realize the automatic, fast, non-destructive sampling of piperazine rectification separation process, and directly analyze representative sample, while having system backflush purification and sample recovery treatment function after detection, ensure the real-time of analysis result and the safety, environmental protection of entire operation process.

Description

Technical Field

[0001] This invention belongs to the field of compound testing technology, specifically relating to an online gas chromatography analysis and detection device for the continuous production of high-purity piperazine. Background Technology

[0002] Piperazine (1,4-diazacyclohexane) is an important cyclic amine compound, readily undergoing functional group modification and structural derivatization. It is widely used as a key raw material in the synthesis of pharmaceutical intermediates, polymer materials, and other fine chemicals. In its production process, distillation is the core step in obtaining high-purity (≥99%) piperazine products. The separation efficiency of this process directly determines the purity and yield of the final product. Therefore, real-time monitoring of the materials within the distillation column is crucial for improving yield, reducing costs, and minimizing scrap rates.

[0003] Currently, the content detection in the piperazine distillation separation process mainly follows the national standard GB 38121-2019. After manual sampling, the solid sample is sent to the laboratory to be dissolved, and then gas chromatography is used for offline analysis. This method relies on manual sampling and offline analysis, which is time-consuming and cannot provide real-time feedback on production status. At the same time, piperazine is volatile and irritating, posing environmental risks during the sampling process.

[0004] Online gas chromatography (GC) offers significant advantages over offline methods in terms of efficiency and timeliness for precise control of compound production processes due to its real-time transmission, sampling, and measurement capabilities. However, its widespread application in organic chemical production faces challenges due to the complex and diverse physicochemical properties of raw materials, intermediates, and products. The online sampling and analysis system proposed in patent CN201410136946.0 targets gaseous samples. However, for piperazine with a melting point of 109℃ and a boiling point of 146℃, its narrow temperature transition range and unique phase transition characteristics necessitate specialized liquid sampling and heating techniques. This significantly limits the applicability of this method in online GC analysis of piperazine.

[0005] Therefore, developing an online gas chromatography analysis device for piperazine that can be integrated into a distillation separation production line, is easy to operate, has a fast response, and provides reliable results is of great practical significance for achieving precise control, improving product quality, reducing operational risks, and increasing economic benefits. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide an online gas chromatography analysis and detection device for the continuous production of high-purity piperazine that is simple in structure and easy to use.

[0007] To solve the above-mentioned technical problems, this utility model provides an online gas chromatography analysis and detection device for continuous production of high-purity piperazine, including: a distillation column and a DCS system. The side outlet of the distillation column is connected to the sampling loop pipeline and then splits into two paths. One path is connected to the side inlet of the distillation column through a first switching valve, and the other path is connected to a sample switching valve, a filter, a backflush valve, an automatic injection valve, a liquid metering loop, a sixth switching valve, a vaporization chamber, and a six-way valve.

[0008] The six ports of the six-way valve are respectively connected to the outlet of the vaporization chamber, the inlet and outlet of the gas metering loop, the second N2 carrier gas pipeline, the inlet of the check valve, and the inlet of the split sampler.

[0009] The split injector has two outlets: one is connected to the flame ionization detector via the chromatographic column, and the other is connected to the sample recovery vessel; the check valve outlet is connected to the sample recovery vessel.

[0010] As an improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0011] A branch is provided on the connecting pipe between the sample switch valve and the filter, and the waste liquid tank is connected to the connecting pipe between the sample switch valve and the filter after passing through the second switch valve.

[0012] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0013] A branch is provided on the connecting pipe between the backflush valve and the automatic sampling valve. The backflush steam source pipe is connected to the connecting pipe between the backflush valve and the automatic sampling valve after passing through the third switch valve.

[0014] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0015] A branch is provided on the connecting pipe between the automatic injection valve and the liquid metering loop, which is connected to the first N2 carrier gas pipeline.

[0016] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0017] A branch is provided on the connecting pipe between the liquid metering loop and the sixth switch valve. The sample recovery tank is connected to the connecting pipe between the liquid metering loop and the sixth switch valve after passing through the fifth switch valve.

[0018] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0019] A sampling probe is installed on the sampling circuit pipeline;

[0020] The hydrogen flame ionization detector is connected to both the hydrogen source pipeline and the air source pipeline.

[0021] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0022] The first N2 carrier gas pipeline, the hydrogen source pipeline, the air source pipeline, and the second N2 carrier gas pipeline are all equipped with pressure reducing valves and switching valves.

[0023] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0024] The six-way valve has two connection states: a filling position and an injection position. In the filling position, the outlet of the vaporization chamber is connected to the inlet of the gas metering loop through the six-way valve, and the outlet of the gas metering loop is connected to the inlet of the check valve at the same time. In the injection position, the second N2 carrier gas pipeline, the gas metering loop, and the inlet of the split injector are connected sequentially through the six-way valve.

[0025] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0026] The hydrogen flame ionization detector is connected to the DCS system signal; the first switching valve, sample switching valve, second switching valve, third switching valve, automatic sample injection valve, fifth switching valve, sixth switching valve, six-way valve, as well as the pressure reducing valve and switching valve on the first N2 carrier gas pipeline, hydrogen source pipeline, air source pipeline, and second N2 carrier gas pipeline are all electrically driven switching valves, and all are connected to the DCS system signal.

[0027] As a further improvement to the online gas chromatography analysis and detection device for continuous production of high-purity piperazine of this utility model:

[0028] All pipes and components from the sampling loop pipeline to the vaporization chamber are insulated with double-layer heat tracing pipes.

[0029] The sixth switching valve, vaporization chamber, six-way valve, gas metering loop, split sampler, and flame ionization detector are all located in an explosion-proof cabinet.

[0030] The beneficial effects of this utility model are mainly reflected in:

[0031] 1. This utility model can achieve automatic, rapid and non-destructive sampling and direct analysis of representative samples. It also has the functions of system backflushing purification and sample recovery after detection, ensuring the accuracy and real-time nature of the analysis results and the safety and environmental protection of the entire operation process.

[0032] 2. This utility model adopts double-layer heat tracing and insulation technology, which keeps the sample in a stable liquid state from the sampling point to the analysis equipment, completely avoiding the distortion of analysis results caused by trace bubbles generated during the vaporization process, and ensuring that the analysis results accurately and truly reflect the process conditions.

[0033] 3. This utility model achieves real-time and continuous monitoring of the distillation separation process through automated rapid circulation loop and quantitative injection. The data can be directly used for immediate adjustment of process parameters, which greatly improves the accuracy of product quality control.

[0034] 4. This utility model realizes closed-loop online sampling and analysis, avoiding direct contact between operators and toxic and harmful samples, thus protecting personnel health; residual samples, backflushing waste and detection exhaust gas after analysis are effectively collected and treated, with no direct discharge, reducing environmental pollution;

[0035] 5. The entire device of this utility model is fully automatically controlled by the control unit, which can realize digital operation and communicate with the factory's DCS system, providing key data support for building an intelligent manufacturing closed-loop control system. Attached Figure Description

[0036] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of an online gas chromatography analysis and detection device for continuous production of high-purity piperazine according to the present invention; Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0039] Example 1: An online gas chromatography analysis and detection device for continuous production of high-purity piperazine, such as... Figure 1 As shown.

[0040] After the side outlet of the piperazine production line distillation column 1 is connected to the sampling loop pipeline 2, it splits into two paths. One path connects to the side inlet of distillation column 1 via the first switch valve 4, and the other path connects to the inlet of vaporization chamber 11 via the sample switch valve 5, filter 6, backflush valve 7, automatic injection valve 8, liquid metering loop 9, and sixth switch valve 106. Simultaneously, there are connecting pipelines between sample switch valve 5 and filter 6, between backflush valve 7 and automatic injection valve 8, between automatic injection valve 8 and liquid metering loop 9, and between liquid metering loop 9 and sixth switch valve 106. Each component has a branch line: the waste liquid tank 21 is connected to the connection pipe between the sample switch valve 5 and the filter 6 after passing through the second switch valve 102; the backflush steam source pipe 20 is connected to the connection pipe between the backflush valve 7 and the automatic sampling valve 8 after passing through the third switch valve 103; a branch line on the connection pipe between the automatic sampling valve 8 and the liquid metering loop 9 is connected to the first N2 carrier gas pipe 17; and the sample recovery tank 10 is connected to the connection pipe between the liquid metering loop 9 and the sixth switch valve 106 after passing through the fifth switch valve 105. The first switch valve 4 is used to cut off the sample return loop to the distillation column 1 during sample collection; the sample switch valve 5 is used to control the opening and closing of the sampling flow path; the filter 6 is used to remove mechanical impurities carried out by the distillation column 1 and from the sampling loop pipe; the backflush valve 7 is a differential pressure valve; and the liquid metering loop 9 is used to accurately measure the volume of the liquid sample. After sampling, the third switch valve 103 and the second switch valve 102 are opened, and the backflush steam passes through the backflush valve 7 and the filter 6 before reaching the waste liquid tank 21. A sampling probe 3 is provided on the sampling loop pipe 2 (located before the first switching valve 4 and the sample switching valve 5). The sampling probe 3 is inserted into the loop pipe 2 for fast loop and sample sampling.

[0041] The first N2 carrier gas line 17 is equipped with a pressure reducing valve and a switching valve, used to introduce N2 carrier gas from the N2 gas source as the carrier gas for the vaporized sample flowing into the vaporization chamber 11. A six-way valve 12 is located after the vaporization chamber 11. The six ports of the six-way valve 12 are respectively connected to the outlet of the vaporization chamber 11, the inlet and outlet of both ends of the gas metering loop 13, the second N2 carrier gas line 23, the inlet of the check valve 110, and the inlet of the split sampler 14. The second N2 carrier gas line 23 is equipped with a pressure reducing valve and a switching valve, used to connect to the N2 gas source and introduce the sample carrier gas to drive the sample gas flow. The outlet of the check valve 110 is connected to the sample recovery tank 10, and the opening direction of the check valve 110 is from the six-way valve 12 towards the sample recovery tank 10.

[0042] The six-way valve 12 has two connection states: a filling position and an injection position. When the six-way valve 12 is in the filling position, it connects the outlet of the vaporization chamber 11 to the inlet of the gas metering loop 13 to transfer the vaporized sample from the vaporization chamber 11 into the gas metering loop 13. Simultaneously, it connects the outlet of the gas metering loop 13 to the inlet of the check valve 110 so that excess gas after the gas metering loop 13 is filled is discharged into the recovery tank 10 via the check valve 110. When the six-way valve 12 is in the injection position, it sequentially connects the second N2 carrier gas pipeline 23, the inlet and outlet of both ends of the gas metering loop 13, and the inlet of the split sampler 14. The carrier gas N2 passes through the six-way valve 12 and then through the gas metering loop 13, carrying the sample gas into the split sampler 14.

[0043] The outlet of the split injector 14 is divided into two paths: one path is connected to the flame ionization detector 16 (FID) via the chromatographic column 15, and the other path leads to the sample recovery tank 10.

[0044] The flame ionization detector 16 is also connected to the hydrogen source line 18 and the air source line 19, both of which are equipped with pressure reducing valves and switching valves. The flame ionization detector 16 is connected to the DCS system 24. The signal detected by the flame ionization detector 16 is processed and analyzed by the dedicated software of the gas chromatograph. After digital conversion, the processed data is transmitted to the DCS system 24, achieving standardized and normalized signal transmission. The sixth switching valve 106, vaporization chamber 11, six-way valve 12, gas metering loop 13, split injector 14, and flame ionization detector 16 are all housed in an explosion-proof cabinet 25 to prevent explosions caused by high temperatures and hydrogen.

[0045] Sample recovery tank 10 receives excess material from liquid metering loop 9, six-way valve 12, and split sampler 14; waste tank 21 receives backflushing waste; all pipes and components from sampling loop pipe 2 to vaporization chamber 11 are insulated using double-layer heat-traced pipes. The double-layer heat-traced pipes consist of electric heat tracing and a steam jacket. The inner layer of the jacket is a sampling tube wrapped with electric heat tracing tape, and steam is introduced through the middle of the jacket. The insulation temperature range is 120°C to 140°C. Steam heat tracing provides a localized high-temperature environment to alleviate the cold spot effect and insufficient temperature control accuracy of the electric heat tracing tape. Except for the backflush valve 7, the pressure reducing valves and switching valves on the first switching valve 4, sample switching valve 5, second switching valve 102, third switching valve 103, automatic sample injection valve 8, fifth switching valve 105, sixth switching valve 106, six-way valve 12, as well as the pressure reducing valves and switching valves on the first N2 carrier gas pipeline 17, hydrogen source pipeline 18, air source pipeline 19, and second N2 carrier gas pipeline 23 are all electrically driven switching valves, and are all connected to the DCS system 24 for signal connection. The DCS system 24 controls the opening and closing of each valve, thereby realizing fully automatic control.

[0046] The specific method of using this utility model is as follows:

[0047] 1. Sampling Analysis

[0048] The first switch valve 4, the second switch valve 102, the third switch valve 103, the sixth switch valve 106, and the pressure reducing valve and switch valve on the first N2 carrier gas line 17 are all closed. The sample switch valve 5, the automatic sample injection valve 8, and the fifth switch valve 105 are all opened. The pressure reducing valves and switch valves on the hydrogen source line 18, the air source line 19, and the second N2 carrier gas line 23 are all opened.

[0049] The material in distillation column 1 enters filter 6 through sampling probe 3 and sample switch valve 5, and the liquid is filtered.

[0050] The filtered sample is filled with liquid metering loop 9 through automatic injection valve 8, and excess sample is discharged to sample recovery tank 10.

[0051] After the liquid metering loop 9 is filled, the sample switch valve 5, the automatic injection valve 8 and the fifth switch valve 105 are closed, and the first switch valve 4 is opened, so that the material returns to the distillation column 1.

[0052] 2. After the automatic injection valve 8 is switched to the closed position, the sixth switch valve 106 is opened, and the pressure reducing valve and switch valve on the first N2 carrier gas line 17 are opened. The six-way valve 12 is switched to the sample filling position. N2 is pushed into the liquid metering loop 9 through the first N2 carrier gas line 17. The sample is carried into the vaporization chamber 11. The sample vaporizes and flows into the gas metering loop 13.

[0053] After the gas metering loop 13 is filled with sample gas, the excess gas in the vaporization chamber 11 is discharged into the sample recovery tank 10 through the check valve 110.

[0054] Then, close the pressure reducing valve and the switching valve on the first N2 carrier gas line 17, close the sixth switching valve 106, switch the six-way valve 12 to the injection position, and let N2 pass through the second N2 carrier gas line 23 and the six-way valve 12 and then through the gas metering loop 13 to bring the sample gas into the split injector 14.

[0055] Then, a portion of the sample gas enters the chromatographic column 15 for separation and is detected by the flame ionization detector 16. The signal is processed and analyzed by the dedicated software of the gas chromatograph, and the processed data is transmitted to the DCS system 24. Excess sample gas in the split injector 14 flows into the sample recovery container 10 for recovery and storage.

[0056] After the analysis is completed, the second switch valve 102 is opened, and then the third switch valve 103 is opened to introduce backflushing steam. The backflushing valve 7 backflushes the filter 6, and the material in the pipeline and the mechanical impurities filtered out are discharged into the waste liquid tank 21. In addition, during the maintenance phase, the sample switch valve 5 is closed, which allows for safe maintenance or replacement of all downstream components without affecting the normal operation of the main process.

[0057] Finally, it should be noted that the above examples are merely a few specific embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A device for on-line gas chromatographic analysis of the detection of continuous production of high purity piperazine, comprising a rectification column (1) and a DCS system (24), characterized by the fact that it comprises: After the side outlet of the distillation column (1) is connected to the sampling loop pipeline (2), it is divided into two paths. One path is connected to the side inlet of the distillation column (1) through the first switch valve (4), and the other path is connected to the sample switch valve (5), filter (6), backflush valve (7), automatic injection valve (8), liquid metering loop (9), sixth switch valve (106), vaporization chamber (11) and six-way valve (12). The six ports of the six-way valve (12) are respectively connected to the outlet of the vaporization chamber (11), the inlet and outlet of the gas metering ring (13), the second N2 carrier gas pipeline (23), the inlet of the check valve (110) and the inlet of the split injector (14); The outlet of the split injector (14) is divided into two paths: one path is connected to the flame ionization detector (16) via the chromatographic column (15), and the other path is connected to the sample recovery vessel (10); the outlet of the check valve (110) is connected to the sample recovery vessel (10).

2. The online gas chromatography analysis and detection device for continuous production of high-purity piperazine according to claim 1, characterized in that: A branch is provided on the connecting pipe between the sample switch valve (5) and the filter (6), and the waste liquid tank (21) is connected to the connecting pipe between the sample switch valve (5) and the filter (6) after passing through the second switch valve (102).

3. The online gas chromatography analysis and detection device for continuous production of high-purity piperazine according to claim 2, characterized in that: A branch is provided on the connecting pipe between the backflush valve (7) and the automatic sampling valve (8). The backflush steam source pipe (20) is connected to the connecting pipe between the backflush valve (7) and the automatic sampling valve (8) after passing through the third switch valve (103).

4. The online gas chromatographic analysis and detection device for continuous production of high-purity piperazine according to claim 3, characterized in that: A branch is provided on the connecting pipe between the automatic injection valve (8) and the liquid metering ring (9), which is connected to the first N2 carrier gas pipeline (17).

5. The online gas chromatography analysis and detection device for continuous production of high-purity piperazine according to claim 4, characterized in that: A branch is provided on the connecting pipe between the liquid metering ring (9) and the sixth switch valve (106). The sample recovery tank (10) is connected to the connecting pipe between the liquid metering ring (9) and the sixth switch valve (106) after passing through the fifth switch valve (105).

6. The online gas chromatographic analysis and detection device for continuous production of high-purity piperazine according to claim 5, characterized in that: A sampling probe (3) is provided on the sampling circuit pipe (2); The hydrogen flame ionization detector (16) is connected to the hydrogen source pipeline (18) and the air source pipeline (19), respectively.

7. The online gas chromatographic analysis and detection device for continuous production of high-purity piperazine according to claim 6, characterized in that: The first N2 carrier gas pipeline (17), the hydrogen source pipeline (18), the air source pipeline (19), and the second N2 carrier gas pipeline (23) are all equipped with pressure reducing valves and switching valves.

8. The online gas chromatographic analysis and detection device for continuous production of high-purity piperazine according to claim 7, characterized in that: The six-way valve (12) has two connection states: a filling position and an injection position. In the filling position, the outlet of the vaporization chamber (11) is connected to the inlet of the gas metering ring (13) through the six-way valve (12), and the outlet of the gas metering ring (13) is connected to the inlet of the check valve (110) at the same time. In the injection position, the inlet of the second N2 carrier gas pipeline (23), the gas metering ring (13), and the split injector (14) are connected in sequence through the six-way valve (12).

9. The online gas chromatography analysis and detection device for continuous production of high-purity piperazine according to claim 8, characterized in that: The hydrogen flame ionization detector (16) is connected to the DCS system (24) via signal connection; the pressure reducing valves and switching valves on the first switching valve (4), sample switching valve (5), second switching valve (102), third switching valve (103), automatic sample injection valve (8), fifth switching valve (105), sixth switching valve (106), six-way valve (12), as well as the pressure reducing valves and switching valves on the first N2 carrier gas pipeline (17), hydrogen source pipeline (18), air source pipeline (19), and second N2 carrier gas pipeline (23) are all electrically driven switching valves and are all connected to the DCS system (24) via signal connection.

10. The online gas chromatographic analysis and detection device for continuous production of high-purity piperazine according to claim 9, characterized in that: All pipes and components from the sampling loop pipe (2) to the vaporization chamber (11) are insulated with double-layer heat tracing pipes; The sixth switching valve (106), vaporization chamber (11), six-way valve (12), gas metering ring (13), split sampler (14) and hydrogen flame ionization detector (16) are all inside the explosion-proof cabinet (25).

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