Analysis and detection system for inorganic impurities in high-purity ammonia

Abstract

The utility model discloses an analysis and detection system for inorganic impurities in high-purity ammonia, comprising: a backflush valve, a chromatographic column selection valve, a detector selection valve, a first separation column, a second separation column, a third separation column, a fourth separation column and a detector; the backflush valve is a ten-way valve, and the chromatographic column selection valve and the detector selection valve are both four-way valves. The utility model adopts a three-valve four-column mode, and the chromatographic switching valve only uses one ten-way valve and two four-way valves. A double pre-separation column scheme is adopted. Even if the ammonia of the gas source to be detected contains a high moisture content, it can be removed in the first separation column and the second separation column, and the ammonia can also be backflush out through the ten-way valve. The cost is low, the process is simple, and it is easy to operate. The utility model can more effectively separate inorganic impurities in ammonia, has a good separation effect, can eliminate the interference of the main peak ammonia, and the peak shape is symmetrical, meeting the requirements.

Description

Technical Field

[0001] The utility model belongs to the field of analysis and testing, and specifically relates to an analysis and detection system for inorganic impurities in high-purity ammonia. Background Art

[0002] High-purity ammonia is used in many occasions. High-purity ammonia refers to ammonia with a purity of more than 99.9995%. The inorganic impurities in high-purity ammonia mainly include: hydrogen, oxygen, nitrogen, methane, carbon monoxide and carbon dioxide inorganic non-condensable gases.

[0003] The existing method mainly analyzes the impurity content in ammonia by chromatography. Because ammonia is weakly ammonium and easily combines with water, especially when ammonia contains a certain amount of water, it is very easy to remain in the chromatographic column, resulting in reduced column efficiency, difficulty in separation from impurities, and interference with peaks to a certain extent, resulting in peak tailing, peak deformation and other phenomena.

[0004] To overcome the above problems, multi-valve and multi-column switching is considered in chromatographic analysis to back-blow ammonia out of the chromatographic column, but its structure is complex, the process is cumbersome, the debugging difficulty coefficient is high, and high skills are required for the operator. Utility Model Content

[0005] In order to solve the above technical problems, the utility model proposes an analysis and detection system for inorganic impurities in high-purity ammonia.

[0006] In order to achieve the above object, the technical solution of the utility model is as follows:

[0007] On the one hand, the utility model discloses an analysis and detection system for inorganic impurities in high-purity ammonia, comprising: a backflush valve, a chromatographic column selection valve, a detector selection valve, a first separation column, a second separation column, a third separation column, a fourth separation column and a detector;

[0008] The backflush valve is a ten-way valve, and the column selection valve and detector selection valve are both four-way valves;

[0009] The first valve port of the back-blowing valve is connected to the gas source to be detected, the second valve port of the back-blowing valve is connected to the ninth valve port thereof through a pipeline equipped with a quantitative tube, the tenth valve port of the back-blowing valve is connected to the outlet through a pipeline, the third valve port of the back-blowing valve is connected to carrier gas one, the fourth valve port of the back-blowing valve is connected to the eighth valve port thereof through a pipeline equipped with a first separation column, the seventh valve port of the back-blowing valve is connected to the outlet through a pipeline, the sixth valve port of the back-blowing valve is connected to carrier gas two, the fifth valve port of the back-blowing valve is connected to the third valve port of the chromatographic column selection valve through a pipeline equipped with a second separation column, the first valve port of the chromatographic column selection valve is connected to the first valve port of the detector selection valve through a pipeline equipped with a fourth separation column, the second valve port of the detector selection valve is connected to the outlet through a pipeline, the second valve port of the chromatographic column selection valve is connected to carrier gas three, the fourth valve port of the chromatographic column selection valve is connected to the fourth valve port of the detector selection valve through a pipeline equipped with a third separation column, and the third valve port of the detector selection valve is connected to the detector through a pipeline;

[0010] The first separation column is used to separate air, methane, carbon dioxide, and ammonia, and remove the water content in ammonia;

[0011] The second separation column is used to separate air, methane and carbon dioxide;

[0012] The third separation column is used to separate hydrogen, oxygen, nitrogen, methane and carbon monoxide;

[0013] The fourth separation column is used to separate carbon dioxide.

[0014] On the basis of the above technical solution, the following improvements can be made:

[0015] As a preferred solution, the first separation column is a carbon molecular sieve column filled with activated carbon.

[0016] As a preferred solution, the second separation column is a silica gel column filled with silica gel.

[0017] As a preferred solution, the third separation column is a 5A column filled with 5A molecular sieve.

[0018] As a preferred solution, the fourth separation column is a Tenex column filled with porous polymer beads.

[0019] The utility model discloses an analysis and detection system for inorganic impurities in high-purity ammonia, which has the following beneficial effects:

[0020] First, the utility model adopts a three-valve four-column mode, and the chromatographic switching valve only uses one ten-way valve and two four-way valves. A double pre-separation column solution is adopted. Even if the ammonia gas of the gas source to be detected contains a high moisture content, it can be removed in the first separation column and the second separation column. At the same time, the ammonia gas can also be backblown out through the ten-way valve. The cost is low, the process is simple, and the operation is easy.

[0021] Secondly, the utility model can more effectively separate inorganic impurities in ammonia, has good separation effect, can eliminate the interference of main peak ammonia, and has a uniform peak shape, which meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of an analysis and detection system provided in an embodiment of the utility model (the backflush valve, the chromatographic column selection valve, and the detector selection valve are all in a closed state).

[0024] Figure 2 A schematic structural diagram of an analysis and detection system provided in an embodiment of the utility model (a backflush valve and a chromatographic column selection valve are in an open state, and a detector selection valve is in a closed state).

[0025] Figure 3 A schematic structural diagram of an analysis and detection system provided in an embodiment of the utility model (a backflush valve and a chromatographic column selection valve are in a closed state, and a detector selection valve is in an open state).

[0026] Wherein: 1-backflush valve, 2-chromatographic column selection valve, 3-detector selection valve, 41-first separation column, 42-second separation column, 43-third separation column, 44-fourth separation column, 5-detector, 6-quantitative tube. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] Using ordinal numbers “first,” “second,” “third,” etc. to describe common objects merely indicates that different instances of similar objects are involved and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0030] In addition, the expression of “comprising” an element is an “open” expression, which merely means that corresponding components or steps exist, and should not be interpreted as excluding additional components or steps.

[0031] In order to achieve the purpose of the utility model, in some embodiments of a system for analyzing and detecting inorganic impurities in high-purity ammonia, as Figure 1 As shown, the analysis and detection system includes: a backflush valve 1, a chromatographic column selection valve 2, a detector 5 selection valve 3, a first separation column 41, a second separation column 42, a third separation column 43, a fourth separation column 44 and a detector 5;

[0032] The backflush valve 1 is a ten-way valve, and the chromatographic column selection valve 2 and the detector 5 selection valve 3 are both four-way valves;

[0033] The first valve port of the back-blowing valve 1 is connected to the gas source to be detected, the second valve port of the back-blowing valve 1 is connected to its ninth valve port through a pipeline equipped with a quantitative tube 6, the tenth valve port of the back-blowing valve 1 is connected to the outlet through a pipeline, the third valve port of the back-blowing valve 1 is connected to the carrier gas 1, the fourth valve port of the back-blowing valve 1 is connected to its eighth valve port through a pipeline equipped with a first separation column 41, the seventh valve port of the back-blowing valve 1 is connected to the outlet through a pipeline, the sixth valve port of the back-blowing valve 1 is connected to the carrier gas 2, and the fifth valve port of the back-blowing valve 1 is connected to the carrier gas 2 through a pipeline equipped with a second separation column 42. The pipeline is connected to the third valve port of the chromatographic column selection valve 2, the first valve port of the chromatographic column selection valve 2 is connected to the first valve port of the detector 5 selection valve 3 through a pipeline installed with a fourth separation column 44, the second valve port of the detector 5 selection valve 3 is connected to the outlet through a pipeline, the second valve port of the chromatographic column selection valve 2 is connected to the carrier gas three-way, the fourth valve port of the chromatographic column selection valve 2 is connected to the fourth valve port of the detector 5 selection valve 3 through a pipeline installed with a third separation column 43, and the third valve port of the detector 5 selection valve 3 is connected to the detector 5 through a pipeline;

[0034] The first separation column 41 is used to separate air, methane, carbon dioxide, and ammonia, and remove the water content in ammonia;

[0035] The second separation column 42 is used to separate air, methane and carbon dioxide;

[0036] The third separation column 43 is used to separate hydrogen, oxygen, nitrogen, methane and carbon monoxide;

[0037] The fourth separation column 44 is used to separate carbon dioxide.

[0038] The carrier gas 1, carrier gas 2 and carrier gas 3 are ultrapure helium. The detector 5 is a gas chromatograph with a PDD (Pulsed Discharge Detector).

[0039] Furthermore, the first separation column 41 is a carbon molecular sieve column filled with activated carbon.

[0040] Furthermore, the second separation column 42 is a silica gel column filled with silica gel.

[0041] Furthermore, the third separation column 43 is a 5A column filled with 5A molecular sieve.

[0042] Furthermore, the fourth separation column 44 is a Tenex column filled with porous polymer beads.

[0043] The first separation column 41 and the second separation column 42 are pre-separation columns.

[0044] The method for analyzing and detecting inorganic impurities in high-purity ammonia is to use the above-mentioned analysis and detection system for detection. When the gas source to be detected is the sample gas and the standard gas, the following steps are performed respectively, specifically including:

[0045] Step S1: backflush valve 1, chromatographic column selection valve 2, and detector 5 selection valve 3 are all in a closed state;

[0046] Step S2: synchronously opening the backflush valve 1 and the chromatographic column selection valve 2, and starting timing;

[0047] When the timing reaches time point t1 (e.g. 3.3 min), close backflush valve 1;

[0048] After the timing reaches time point t2 (e.g., 4 min), close the chromatographic column selection valve 2;

[0049] Step S3: After the timing reaches time point t3 (e.g., 7 minutes), the detector 5 selection valve 3 is opened;

[0050] After the timing reaches time point t4 (eg, 10 minutes), the detector 5 selection valve 3 is closed.

[0051] The standard gas adopts the external standard single-point calibration method, with helium as the background gas, and is configured with 1ppm hydrogen, 1ppm oxygen, 1ppm nitrogen, 1ppm methane, 1ppm carbon monoxide, 1ppm carbon dioxide, and 50ppm ammonia. If the impurity content in ammonia is less than 50ppb or lower, for accurate quantification, the standard gas should be diluted with a diluter and then tested. The dilution concentration depends on the impurity content, and the diluted standard concentration should be close to the impurity concentration in the sample gas.

[0052] When performing analysis and detection, the gas source to be detected is first used as the sample gas, and steps S1 to S3 are performed. The hydrogen, oxygen, nitrogen, methane, carbon monoxide and carbon dioxide inorganic non-condensable gases in the ammonia are all analyzed out. On the chromatogram, the area of ​​each component is Ai;

[0053] Then, the backflush valve 1, the chromatographic column selection valve 2, and the detector 5 selection valve 3 all return to the initial state;

[0054] Next, the gas source to be detected is used as the standard gas (a diluter can be used to dilute the gas accordingly according to the concentration to match the concentration of the impurities), and then steps S1 to S3 are performed to obtain the area of ​​each component on the chromatogram as As.

[0055] The component content in the sample is calculated according to the following formula:

[0056] Φi=(Ai / As)*Φs;

[0057] Where:

[0058] Φi is the content of component i in the sample gas, in ppm;

[0059] Φs is the content of component i in the standard gas, in ppm;

[0060] Ai is the peak area size in the spectrum corresponding to component i in the sample gas (pA.s);

[0061] As is the peak area size (pA.s) in the spectrum corresponding to component i in the standard gas.

[0062] The arithmetic mean of the results of two parallel measurements of the samples was taken as the final analysis result, and the relative deviation of the two measurement values ​​was no more than ±10%.

[0063] Further, in step S1, when the backflush valve 1, the chromatographic column selection valve 2, and the detector 5 selection valve 3 are all in the closed state, as Figure 1 As shown;

[0064] The gas source to be tested enters from the first valve port of the back-blowing valve 1, flows out from the second valve port of the back-blowing valve 1, enters the ninth valve port of the back-blowing valve 1 through the pipeline equipped with the quantitative tube 6, and is discharged from the tenth valve port of the back-blowing valve 1;

[0065] The carrier gas 1 enters from the third valve port of the back-blowing valve 1, flows out from the fourth valve port of the back-blowing valve 1, enters the eighth valve port of the back-blowing valve 1 through the pipeline equipped with the first separation column 41, and is discharged from the seventh valve port of the back-blowing valve 1;

[0066] The carrier gas 2 enters from the sixth valve port of the backflush valve 1, flows out from the fifth valve port of the backflush valve 1, enters the third valve port of the chromatographic column selection valve 2 through the pipeline installed with the second separation column 42, flows out from the first valve port of the chromatographic column selection valve 2, enters the first valve port of the detector 5 selection valve 3 through the pipeline installed with the fourth separation column 44, and is discharged from the second valve port of the detector 5 selection valve 3;

[0067] Carrier gas three enters from the second valve port of the chromatographic column selection valve 2, flows out from the fourth valve port of the chromatographic column selection valve 2, enters the fourth valve port of the detector 5 selection valve 3 through the pipeline installed with the third separation column 43, and then flows out from the third valve port of the detector 5 selection valve 3 and enters the detector 5 through the pipeline.

[0068] Further, in step S2, when the backflush valve 1 and the chromatographic column selection valve 2 are in the open state, and the detector 5 selection valve 3 is in the closed state, as Figure 2 As shown;

[0069] The gas source to be tested enters from the first valve port of the back-blowing valve 1 and is discharged from the tenth valve port of the back-blowing valve 1;

[0070] The carrier gas enters from the third valve port of the back-blowing valve 1, flows out from the second valve port of the back-blowing valve 1, and then, through a pipeline equipped with a doser, delivers a quantitative amount of the gas source to be detected to the ninth valve port of the back-blowing valve 1, and then flows out from the eighth valve port of the back-blowing valve 1, enters the fourth valve port of the back-blowing valve 1 through a pipeline equipped with a first separation column 41, and then flows out from the fifth valve port of the back-blowing valve 1, enters the third valve port of the chromatographic column selection valve 2 through a pipeline equipped with a second separation column 42, and then flows out from the fourth valve port of the chromatographic column selection valve 2, enters the fourth valve port of the detector 5 selection valve 3 through a pipeline equipped with a third separation column 43, and then flows out from the third valve port of the detector 5 selection valve 3, and then enters the detector 5 through the pipeline, and at this time, hydrogen, oxygen, nitrogen, methane, and carbon monoxide in the gas source to be detected are separated and tested;

[0071] The carrier gas 2 enters from the sixth valve port of the back-blowing valve 1 and is discharged from the seventh valve port of the back-blowing valve 1;

[0072] The carrier gas 3 enters from the second valve port of the chromatographic column selection valve 2, flows out from the first valve port of the chromatographic column selection valve 2, enters the first valve port of the detector 5 selection valve 3 through the pipeline equipped with the fourth separation column 44, and is purged and discharged from the second valve port of the detector 5 selection valve 3.

[0073] Further, in step S3, when the backflush valve 1 and the chromatographic column selection valve 2 are in the closed state, and the detector 5 selection valve 3 is in the open state, as Figure 3 As shown;

[0074] The gas source to be tested enters from the first valve port of the back-blowing valve 1, flows out from the second valve port of the back-blowing valve 1, enters the ninth valve port of the back-blowing valve 1 through the pipeline equipped with the quantitative tube 6, and is discharged from the tenth valve port of the back-blowing valve 1;

[0075] The carrier gas enters from the third valve port of the back-blowing valve 1, flows out from the fourth valve port of the back-blowing valve 1, enters the eighth valve port of the back-blowing valve 1 through the pipeline installed with the first separation column 41, and is discharged from the seventh valve port of the back-blowing valve 1. At this time, the gas source to be detected remaining in the first separation column 41 is back-blown out;

[0076] The carrier gas 2 enters from the sixth valve port of the back-blowing valve 1, flows out from the fifth valve port of the back-blowing valve 1, enters the third valve port of the chromatographic column selection valve 2 through the pipeline installed with the second separation column 42, flows out from the first valve port of the chromatographic column selection valve 2, enters the first valve port of the detector 5 selection valve 3 through the pipeline installed with the fourth separation column 44, flows out from the third valve port of the detector 5 selection valve 3, enters the detector 5 through the pipeline, and separates and tests the carbon dioxide;

[0077] Carrier gas 3 enters from the second valve port of the chromatographic column selection valve 2, flows out from the fourth valve port of the chromatographic column selection valve 2, enters the fourth valve port of the detector 5 selection valve 3 through the pipeline installed with the third separation column 43, and then is discharged from the second valve port of the detector 5 selection valve 3.

[0078] Because the sample tested is ammonia, the exhaust outlets vent are connected to the exhaust gas treatment device to avoid discharge into the air to cause environmental pollution and human harm.

[0079] The utility model discloses an analysis and detection system for inorganic impurities in high-purity ammonia, which has the following beneficial effects:

[0080] First, the utility model adopts a three-valve four-column mode, and the chromatographic switching valve only uses one ten-way valve and two four-way valves, and adopts a double pre-separation column solution. Even if the ammonia gas in the gas source to be detected contains a high moisture content, it can be removed in the first separation column 41 and the second separation column 42. At the same time, the ammonia gas can also be backblown out through the ten-way valve, which has low cost, simple process and easy operation.

[0081] Secondly, the utility model can more effectively separate inorganic impurities in ammonia, has good separation effect, can eliminate the interference of main peak ammonia, and has a uniform peak shape, which meets the requirements.

[0082] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0083] In the present utility model, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the utility model according to the specific circumstances.

[0084] The above shows and describes the basic principles and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which shall fall within the scope of the utility model to be protected. The scope of protection of the utility model shall be defined by the attached claims and their equivalents.

Claims

1. An analysis and detection system for inorganic impurities in high-purity ammonia, characterized in that: include: A backflush valve, a chromatographic column selection valve, a detector selection valve, a first separation column, a second separation column, a third separation column, a fourth separation column and a detector; The backflush valve is a ten-way valve, and the chromatographic column selection valve and the detector selection valve are both four-way valves; The first valve port of the back-blowing valve is communicated with a gas source to be detected, the second valve port of the back-blowing valve is communicated with its ninth valve port through a pipeline equipped with a quantitative tube, the tenth valve port of the back-blowing valve is communicated with an outlet through a pipeline, the third valve port of the back-blowing valve is communicated with carrier gas one, the fourth valve port of the back-blowing valve is communicated with its eighth valve port through a pipeline equipped with a first separation column, the seventh valve port of the back-blowing valve is communicated with the outlet through a pipeline, the sixth valve port of the back-blowing valve is communicated with carrier gas two, the fifth valve port of the back-blowing valve is communicated with the third valve port of the chromatographic column selection valve through a pipeline equipped with a second separation column, the first valve port of the chromatographic column selection valve is communicated with the first valve port of the detector selection valve through a pipeline equipped with a fourth separation column, the second valve port of the detector selection valve is communicated with the outlet through a pipeline, the second valve port of the chromatographic column selection valve is communicated with carrier gas three, the fourth valve port of the chromatographic column selection valve is communicated with the fourth valve port of the detector selection valve through a pipeline equipped with a third separation column, and the third valve port of the detector selection valve is communicated with the detector through a pipeline; The first separation column is used to separate air, methane, carbon dioxide, and ammonia, and remove water content in ammonia; The second separation column is used to separate air, methane and carbon dioxide; The third separation column is used to separate hydrogen, oxygen, nitrogen, methane and carbon monoxide; The fourth separation column is used to separate carbon dioxide.

2. The analysis and detection system according to claim 1, characterized in that: The first separation column is a carbon molecular sieve column filled with activated carbon.

3. The analysis and detection system according to claim 1, characterized in that: The second separation column is a silica gel column filled with silica gel.

4. The analysis and detection system according to claim 1, characterized in that: The third separation column is a 5A column filled with 5A molecular sieve.

5. The analysis and detection system according to claim 1, characterized in that: The fourth separation column is a Tenex column filled with porous polymer beads.

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