Gas chromatography detection system for analyzing trace impurity hydrocarbon in ultrapure ammonia

Abstract

The utility model relates to a gas chromatography detection system for analyzing trace impurity hydrocarbon in ultrapure ammonia. Comprising an ultrapure ammonia gas quantitative sampling unit, and the ultrapure ammonia gas quantitative sampling unit is connected with a detection unit through a C1-C3 pre-separation unit; the detection unit comprises a DID detector, an inlet of the DID detector is connected with a fourth interface of a switching valve VIII, a first interface of the switching valve VIII is connected with a third carrier gas pipeline, a second interface of the switching valve VIII is connected with a second emptying pipeline, and a third interface of the switching valve VIII is connected with C1-C3 pre-separation units through a special capillary column; the device has the characteristics of simple structure, reasonable design, simplicity in operation, high detection sensitivity of the system, capability of ensuring that all components do not interfere with each other to generate peaks and capability of preventing main components from polluting a chromatographic column and a detector.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of ultrapure ammonia gas impurity detection, especially relates to a gas chromatography detection system for analyzing trace impurity hydrocarbons in ultrapure ammonia. BACKGROUND

[0002] Ultrapure ammonia is an important chemical material, which is widely used in electronic and semiconductor industries, and is mainly used in LED, photovoltaic and semiconductor fields. Based on the above reasons, the preparation of ultrapure ammonia gas and the analysis of trace impurities are particularly important. The gas chromatography used for ultrapure gas analysis in the prior art usually uses traditional TCD and FID or zirconium oxide detector. The above detection instrument is traditional or backward, the detection sensitivity of the system is reduced, and the detection limit is usually only ppm level, which leads to unreliable detection results. Based on the above reasons, some enterprises use DID detector to improve the detection sensitivity, but because ultrapure ammonia is corrosive, it will cause irreversible damage to the DID detector, which not only affects the detection results, but also increases the detection cost due to the damage of the DID detector. SUMMARY

[0003] The utility model discloses a gas chromatography detection system for analyzing trace impurity hydrocarbons in ultrapure ammonia, which solves the defects in the prior art.

[0004] To achieve the above purpose, the utility model provides the following technical scheme:

[0005] A gas chromatography detection system for analyzing trace impurity hydrocarbons in ultrapure ammonia, which comprises an ultrapure ammonia gas quantitative sampling unit, and the ultrapure ammonia gas quantitative sampling unit is connected to a detection unit through a C1-C3 preseparation unit. The detection unit comprises a DID detector, the inlet of the DID detector is connected to the No. 4 interface of a switching valve VIII, the No. 1 interface of the switching valve VIII is connected to a third carrier gas pipeline, the No. 2 interface of the switching valve VIII is connected to a second venting pipeline, and the No. 3 interface of the switching valve VIII is connected to the C1-C3 preseparation unit through a special capillary column.

[0006] The utility model has the advantages that the use of DID detector can improve the detection sensitivity, and the cooperation with the third carrier gas pipeline can continuously purge the DID detector with the carrier gas in the third carrier gas pipeline when the DID detector is not sampling, so as to avoid the corrosion of the DID detector caused by the enrichment and residue of ammonia gas in the DID detector, thereby improving the detection sensitivity and reducing the detection cost.

[0007] Preferably, the ultra-pure ammonia gas quantitative sampling unit comprises a sample gas inlet pipeline, a sample gas outlet pipeline and a sampling switching valve VI, the switching valve VI is a six-way purge gas switching valve, the switching valve VI is provided with a quantitative ring for sampling, and the first carrier gas pipeline for sending the sample gas to the subsequent section.

[0008] Preferably, the No. 3 interface of the switching valve VI is connected with the sample gas inlet pipeline, the No. 4 interface of the switching valve VI is connected with the sample gas outlet pipeline, the No. 1 interface of the switching valve VI is connected with the first carrier gas pipeline, the quantitative ring is arranged between the No. 2 interface and the No. 5 interface of the switching valve VI, and the No. 6 interface of the switching valve VI is connected with a pre-separation special capillary column in the C1-C3 pre-separation unit.

[0009] Preferably, the C1-C3 pre-separation unit comprises a pre-separation special capillary column, the pre-separation special capillary column is connected with a switching valve V II, and the switching valve V II is a center cutting four-way valve which is connected with a special capillary column gas inlet end in a detection unit.

[0010] Preferably, the No. 1 interface of the switching valve V II is connected with the first vent pipeline, the No. 2 interface of the switching valve V II is connected with a gas outlet end of the pre-separation special capillary column, the No. 3 interface of the switching valve V II is connected with the special capillary column gas inlet end, and the No. 4 interface of the switching valve V II is connected with the second carrier gas channel.

[0011] The gas chromatography detection system for analyzing trace impurity hydrocarbon compounds in ultra-pure ammonia prepared according to the above scheme adopts a DID detector configured with a special pre-separation special capillary column and a special capillary column, improves the column efficiency of the chromatographic column, improves the component separation degree, and further, the gas circuit design in the utility model can meet the characteristics that the carrier gas in the third carrier gas pipeline is used for purging the detector, specifically: the carrier gas in the first carrier gas pipeline can be used for conveying sample gas, the carrier gas in the first carrier gas pipeline can be used for purging the pre-separation special capillary column and the pipeline through the switching valve VI, the carrier gas in the third carrier gas pipeline can be used for purging the pipeline and the DID detector through the switching valve V III, the corrosive gas is prevented from being accumulated and remaining in the analysis system for a long time, the column, the pipeline and the detector are prevented from being corroded and causing irreversible damage, and the utility model has the characteristics of simple structure, reasonable design, simple operation, high detection sensitivity of the system, prevention of mutual interference between components, prevention of main component pollution on the chromatographic column and the detector. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a detection system flow diagram of the utility model;

[0013] Figure 2The schematic view of the first carrier gas pipeline in the utility model for carrying trace impurity hydrocarbon compounds to the pre-separation special capillary column.

[0014] Figure 3 The schematic view of the first carrier gas pipeline in the utility model for carrying trace impurity hydrocarbon compounds to the pre-separation special capillary column.

[0015] In the drawing,

[0016] 1, switching valve VI; 2, switching valve V II; 3, quantitative ring; 4, sample gas inlet pipeline; 5, sample gas outlet pipeline; 6, pre-separation special capillary column; 7, special capillary column; 8, first carrier gas pipeline; 9, second carrier gas channel; 10, third carrier gas pipeline; 11, first vent pipeline; 12, DID detector; 13, switching valve V III; 14, second vent pipeline. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.

[0018] In the description of the utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0019] Reference Figures 1-3The utility model is a gas chromatography detection system for analyzing trace impurity hydrocarbons in ultrapure ammonia. The gas chromatography detection system includes an ultrapure ammonia gas quantitative sampling unit, which is connected to a detection unit via a C1-C3 pre-separation unit. The detection unit includes a DID detector 12, the inlet of the DID detector 12 is connected to the No. 4 interface of the switching valve VIII 13, the No. 1 interface of the switching valve VIII 13 is connected to the third carrier gas pipeline 10, the No. 2 interface of the switching valve VIII 13 is connected to the second vent pipeline 14, and the No. 3 interface of the switching valve VIII 13 is connected to the C1-C3 pre-separation unit via a dedicated capillary column 7. The present invention is applied to gas chromatography detection of trace impurity hydrocarbons in ultrapure ammonia gas. During the detection, corrosive gases such as ammonia inevitably enter the DID detector 12. The present invention purges the DID detector 12 with the carrier gas in the third carrier gas pipeline 10 to prevent the corrosive gases from causing corrosion in the DID detector 12 over a long period of time. Specifically, when the DID detector 12 is not performing detection, the carrier gas in the third carrier gas pipeline 10 purges the DID detector 12, thereby protecting the DID detector 12, further improving detection accuracy, and reducing detection costs.

[0020] Furthermore, the ultra-pure ammonia gas quantitative sampling unit includes a sample gas inlet line 4, a sample gas outlet line 5, and a switching valve VI1 for sampling. The switching valve VI1 is a six-way purge pneumatic switching valve. The switching valve VI1 is equipped with a quantitative loop 3 for sampling and a first carrier gas pipeline 8 for delivering the sample gas to subsequent processing stages. This arrangement allows the present invention to establish a pathway for ultra-pure ammonia gas and sample the ultra-pure ammonia gas in this pathway via the quantitative loop 3 to meet subsequent testing requirements.

[0021] Furthermore, port ③ of the switching valve VI1 is connected to the sample gas inlet pipeline 4, port ④ of the switching valve VI1 is connected to the sample gas outlet pipeline 5, port 1 of the switching valve VI1 is connected to the first carrier gas pipeline 8, a quantitative loop 3 is provided between ports ② and ⑤ of the switching valve VI1, and port 6 of the switching valve VI1 is connected to the pre-separation capillary column 6 in the C1-C3 pre-separation unit. This arrangement not only enables the carrier gas in the first carrier gas pipeline 8 to transport the sample gas, but also enables the pre-separation capillary column 6 and related pipelines to be purged through the switching valve VI1, thereby preventing ammonia from corroding the pre-separation capillary column 6 and related pipelines.

[0022] Furthermore, the C1-C3 pre-separation unit includes a dedicated pre-separation capillary column 6, which is connected to a switching valve VII2, a heart-cutting four-way valve, connected to the inlet end of a dedicated capillary column 7 in the detection unit. The dedicated pre-separation capillary column 6 is used to separate the conventional components from the C1-C3 components. The conventional components are first vented, and then the C1-C3 components are transferred to subsequent processes.

[0023] Furthermore, the No. 1 interface of the switching valve VⅡ2 is connected to the first vent pipe 11, the No. 2 interface of the switching valve VⅡ2 is connected to the outlet end of the pre-separation dedicated capillary column 6, and the No. 3 interface of the switching valve VⅡ2 is connected to the outlet end of the pre-separation dedicated capillary column 6.

[0024] Interface No. 4 is connected to the gas inlet end of the dedicated capillary column 7 , and interface No. 4 in the switching valve VⅡ2 is connected to the second carrier gas channel 9 .

[0025] The working principle of the utility model is as follows: the gas phase detection method of the trace impurity hydrocarbon analysis in ultra-pure ammonia gas is the one-time sampling method of the sample gas. First, the valve VⅠ1 is switched to collect the sample gas. Figure 1 As shown, the sample gas production equipment and / or storage equipment enters the No. ③ interface of the switching valve VI1, the No. ② interface of the switching valve VI1, the quantitative loop 3, the No. ⑤ interface of the switching valve VI1, the No. ④ interface of the switching valve VI1 through the sample gas inlet pipeline 4 and is connected to the sample gas outlet pipeline 5, and then the switching valve VI1 is switched to allow the sample gas to remain in the No. ② interface of VI1, the quantitative loop 3 and the No. ⑤ interface of VI1; when the above sampling is completed, the sampling begins, and the sampling process is one sampling, as shown in FIG. Figure 2 As shown, the carrier gas in the first carrier gas pipeline 8 passes through the No. ① interface of the switching valve VI1, the No. ② interface of the switching valve VI1, the quantitative loop 3, the No. ⑤ interface of the switching valve VI1, and the No. ⑥ interface of the switching valve VI1 to the pre-separation dedicated capillary column 6, thereby realizing the pre-separation of the main component and C1-C3; after the pre-separation of the main component, the main component is vented from the first venting pipeline 11 through the center cutting of the switching valve VI2, and the state of the switching valve VI2 is changed at the same time, as shown in FIG. Figure 3 As shown, the gas path changes the flow path, and the pre-separated components C1-C3 are sent to the dedicated capillary column 7 by the carrier gas from the first carrier gas pipeline 8. The dedicated capillary column 7 completely separates C2H2, C2H4, C2H6, C3H6, and C3H8, and then flows into the DID detector 12 with the carrier gas from the first carrier gas pipeline 8 through the switching valve VIII 13 to respond to the peak. In order to prevent the residual ammonia in the system from causing irreversible damage to the capillary column, detector and other instrument components, and to improve the separation effect of the capillary column, as shown in FIG. Figure 1As shown, the No. 4 interface of the switching valve VⅡ2 is connected with the No. 3 interface, the No. 1 interface of the switching valve VⅡ2 is connected with the No. 2 interface, the carrier gas in the second carrier gas channel 9 is connected with the special capillary column 7 through the No. 4 interface and the No. 3 interface of the switching valve VⅡ2 to carry out purging. In order to prevent a small amount of ammonia gas remaining in the sample gas from causing irreversible corrosion damage to the DID detector 12 during long time analysis, a small amount of ammonia gas is removed from the sample gas through the special capillary column 7. Figure 1 As shown, the No. 2 interface of the switching valve VⅢ13 is connected with the second venting pipeline 14, the No. 4 interface of the switching valve VⅢ13 is connected with the DID detector 12, and the carrier gas in the third carrier gas pipeline 10 continuously purges the DID detector 12 in the state without sample. The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical scheme and the concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A gas chromatographic detection system for the analysis of trace amounts of hydrocarbon impurities in ultra-pure ammonia, characterized in that, The gas chromatography detection system comprises an ultra-pure ammonia gas quantitative sampling unit, the ultra-pure ammonia gas quantitative sampling unit is connected with a detection unit through a C1-C3 pre-separation unit; The detection unit comprises a DID detector (12), the inlet of the DID detector (12) is connected with a No. 4 interface of a switching valve V III (13), a No. 1 interface of the switching valve V III (13) is connected with a third carrier gas pipeline (10), a No. 2 interface of the switching valve V III (13) is connected with a second venting pipeline (14), and a No. 3 interface of the switching valve V III (13) is connected with the C1-C3 pre-separation unit through a special capillary column (7).

2. The system for the detection of trace amounts of hydrocarbon impurities in ultra-pure ammonia by gas chromatography according to claim 1, characterized in that, The ultra-pure ammonia gas quantitative sampling unit comprises a sample gas inlet pipeline (4), a sample gas outlet pipeline (5) and a switching valve V I (1) for sampling, The switching valve V I (1) is a six-way purge pneumatic switching valve, the switching valve V I (1) is provided with a quantitative ring (3) for sampling and a first carrier gas pipeline (8) for sending sample gas to a subsequent section.

3. The system for the detection of trace amounts of hydrocarbon impurities in ultra-pure ammonia by gas chromatography according to claim 2, characterized in that, The No. 3 interface of the switching valve V I (1) is connected with the sample gas inlet pipeline (4), the No. 4 interface of the switching valve V I (1) is connected with the sample gas outlet pipeline (5), the No. 1 interface of the switching valve V I (1) is connected with the first carrier gas pipeline (8), the quantitative ring (3) is arranged between the No. 2 interface and the No. 5 interface of the switching valve V I (1), and the No. 6 interface of the switching valve V I (1) is connected with a pre-separation special capillary column (6) in the C1-C3 pre-separation unit.

4. The system for the detection of trace amounts of hydrocarbon impurities in ultra-pure ammonia by gas chromatography according to claim 2, characterized in that, The C1-C3 pre-separation unit comprises the pre-separation special capillary column (6), the pre-separation special capillary column (6) is connected with a switching valve V II (2), and the switching valve V II (2) is a center-cut four-way valve and is connected with a gas inlet end of a special capillary column (7) in the detection unit.

5. The system for the detection of trace amounts of hydrocarbon impurities in ultra-pure ammonia by gas chromatography according to claim 4, characterized in that, The No. 1 interface of the switching valve V II (2) is connected with a first venting pipeline (11), the No. 2 interface of the switching valve V II (2) is connected with a gas outlet end of the pre-separation special capillary column (6), the No. 3 interface of the switching valve V II (2) is connected with the gas inlet end of the special capillary column (7), and the No. 4 interface of the switching valve V II (2) is connected with a second carrier gas pipeline (9).

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