CN111122275A - A kind of pretreatment system and treatment method of trace gas analysis equipment - Google Patents
A kind of pretreatment system and treatment method of trace gas analysis equipment Download PDFInfo
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- G—PHYSICS
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- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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Abstract
本发明属于气体分析领域，具体涉及一种痕量气体分析设备的预处理系统及处理方法，包括捕集阱a、捕集阱b、冷盘、真空仓、阀组、制冷系统与加热控制系统；所述捕集阱a与所述捕集阱b固定在所述冷盘上，所述捕集阱a和所述捕集阱b与所述冷盘位于所述真空仓内，所述冷盘与所述制冷系统相连，所述捕集阱a和所述捕集阱b通过气体管路分别与所述阀组相连，所述捕集阱a和所述捕集阱b通过导线分别与所述加热控制系统相连。经过预浓缩、转移和分离三个步骤分离将不同种类的样品气分离出来。本发明的痕量气体分析设备的预处理系统可实现样品气的富集、转移、吹扫、分离等目标，提高了痕量气体检测的精度。
The invention belongs to the field of gas analysis, and in particular relates to a pretreatment system and a processing method of a trace gas analysis device, comprising a trap a, a trap b, a cold plate, a vacuum chamber, a valve group, a refrigeration system and a heating control system; The trap a and the trap b are fixed on the cold plate, the trap a, the trap b and the cold plate are located in the vacuum chamber, and the cold plate and the cold plate are located in the vacuum chamber. The refrigeration system is connected, the trap a and the trap b are respectively connected to the valve group through gas pipelines, and the trap a and the trap b are respectively connected to the heating control through wires system connected. Different kinds of sample gases are separated out through three steps of pre-concentration, transfer and separation. The pretreatment system of the trace gas analysis equipment of the present invention can achieve the goals of enrichment, transfer, purging, separation and the like of the sample gas, thereby improving the detection accuracy of the trace gas.
Description
Technical Field
The invention relates to the field of gas analysis, belongs to a part of a high-precision gas analysis instrument, and particularly relates to a pretreatment system and a treatment method of trace gas analysis equipment.
Background
The trace gas is a generic name of a gas which exists for decades and has an extremely low content in the atmosphere, such as halides containing F (fluorine) or Cl (chlorine), which causes harm to the environment, and is a key point and a difficult point of global prevention and treatment. The difficulty is that the content of the PPT-based functional group in the atmosphere is PPT level, the PPT-based functional group detection method is various in types, difficult to capture and distinguish, high in monitoring difficulty and inaccurate in detection result due to the fact that the PPT-based functional group detection method needs step-by-step detection to avoid confusion in detection of similar functional groups. The trapping of the trace gas is that the gas is introduced into a trapping trap containing a porous medium packed bed at a lower temperature, so that the trace gas is absorbed in the packed bed at a low temperature, and is heated once again after being enriched to a certain volume, so that the trace gas is desorbed and separated; the existing pretreatment technology for gas analysis only sets a single trap, traps and releases gas at one time, so that the interference of similar functional groups is not avoided, the interference of residual gas in a pipeline on subsequent detection cannot be solved, and the accuracy, precision and repeatability of a detection result are poor.
Disclosure of Invention
Compared with the prior art, the invention is provided with two trapping traps and a plurality of multi-channel switching valves, can realize the communication of various pipelines, and can realize the targets of enrichment, transfer, purging, separation and the like through the matching of the two trapping traps; the sample can be divided into a plurality of parts, and the parts are respectively stored in the two trapping traps and then are respectively sent to the analysis and detection equipment, so that species confusion caused by the similar functional groups during detection is avoided, interference is eliminated, and the accuracy of the detection result is improved.
Meanwhile, a temperature control system is optimized, the heat transfer efficiency is enhanced, the heat loss is reduced, and the temperature control precision is improved; the multi-way valve is switched to realize the connection of different pipelines, so that residual gas in different pipelines can be purged, and the interference and hidden danger of the residual gas are eliminated; when the analysis is carried out, the equipment is rapidly cooled, the initial state is recovered, and the next sample injection test is prepared, so that the continuous operation can be carried out well and stably, and the repeatability and the real-time monitoring are met.
In order to achieve the above object, in a first aspect, the present invention provides a pretreatment system of a trace gas analysis apparatus, including a trap a, a trap b, a cold plate, a vacuum chamber, a valve set, a refrigeration system and a heating control system; the trapping trap a and the trapping trap b are fixed on the cold plate, the trapping trap a and the trapping trap b are located in the vacuum bin with the cold plate, the cold plate is connected with the refrigerating system, the trapping trap a and the trapping trap b are respectively connected with the valve group through gas pipelines, and the trapping trap a and the trapping trap b are respectively connected with the heating control system through wires.
Further, the valve block comprises: a trap a control valve, a trap b control valve and a transfer valve; the transfer valve, the hydrazine a trapping control valve and the hydrazine b trapping control valve are all multi-channel switching valves;
the transfer valve is respectively communicated with a sample gas inlet, a carrier gas inlet, a trap a control valve outlet, a trap b control valve inlet and a gas outlet through gas pipelines;
the trap a control valve is respectively communicated with the trap a inlet, the trap a outlet and the transfer valve through gas pipelines;
and the trap b control valve is respectively communicated with the trap b inlet, the trap b outlet, the transfer valve and the analysis system through gas pipelines.
Those skilled in the art will appreciate that trap b controls the valve outlet to communicate with the analytical system.
Further, the valve block further comprises a sample switching valve; the sample switching valve is a multi-position selection valve and is respectively connected with the plurality of sample gas inlets and the transfer valve.
It will be appreciated by those skilled in the art that when a sample switching valve is present, the sample gas first enters the sample switching valve and then enters the transfer valve; if there is no sample switching valve, the sample gas enters the transit valve directly.
Furthermore, the control valve of the trap b is also communicated with the carrier gas inlet through a gas pipeline, so that the pipeline is convenient to blow back, and residual gas in the pipeline is reduced.
Furthermore, a gas flow controller is arranged on a pipeline of the transfer valve communicated with the gas outlet.
Furthermore, a gas drier is arranged on a pipeline for communicating the trap a control valve with the transfer valve and a pipeline for communicating the transfer valve with the sample gas inlet.
In a second aspect, the present invention provides a method for processing a pretreatment system of a trace gas analyzer, wherein the method divides a process flow into three stages, and sequentially performs the three stages, including:
① preconcentration step, wherein the temperature of the trap a is set to be low, the sample gas sequentially passes through a transfer valve, an inlet of a control valve of the trap a and is trapped by the trap a, and the gas which is not trapped passes through an outlet of the control valve of the trap a, the transfer valve and a gas flow controller and is discharged to a gas outlet;
② transferring step, namely setting the temperature of the trap b as low temperature, setting the temperature of the trap a as transfer temperature, leading the carrier gas to sequentially pass through a transfer valve, an inlet of a control valve of the trap a and the trap a, and then driving the sample gas in the trap a to enter the trap b through an outlet of the control valve of the trap a, the transfer valve and an inlet of the control valve of the trap b;
③ separating step, setting the temperature of the trap b as the separating temperature, and the carrier gas drives the sample gas in the trap b to pass through the trap b and the outlet of the trap b control valve to drive the gas to the interface of the analysis system.
Further, the method comprises 2 or more transfer steps and separation steps.
Further, the low temperature is less than-100 ℃.
Further, the transfer temperature depends on the target gas, e.g., NF3The gas transfer temperature was-120 ℃ and CH2Cl2The transfer temperature of the gas was 50 ℃.
One or more technical schemes provided by the invention at least have the following technical effects or advantages:
according to the pretreatment system of the trace gas analysis equipment, the double trapping traps are tightly connected with the temperature control system and are connected with the outside and the analysis equipment through the valve and the pipeline thereof, and different passages are realized according to the switching of valve sites; the trapping trap is influenced by temperature, the sample stored in the trapping trap is separated, the sample is driven by the circulating carrier gas to enter the pipeline, and the sample flows through different paths by switching the valve sites to reach different end points. Compared with the process flow of a single trap and a fixed gas passage in the prior art, the dynamic process system reduces the precision error of temperature control caused by heat loss and low heat transfer efficiency; the trapping efficiency of the trapping trap is improved, and the separation effect is good; the problem of residual gas interference in a single gas path is solved; the accuracy and repeatability of the detection result and the circulation of the process flow are improved on the whole.
Drawings
FIG. 1 is a basic connection diagram of a pretreatment system of a trace gas analyzing apparatus provided in example 1 of the present invention;
FIG. 2 is a schematic diagram of a first stage of a pretreatment process flow of a trace gas analysis apparatus provided in example 1 of the present invention;
FIG. 3 is a schematic diagram of a second stage of the pretreatment process flow of the trace gas analysis apparatus provided in example 1 of the present invention;
FIG. 4 is a schematic diagram of a third stage of a pretreatment process flow of a trace gas analyzing apparatus provided in example 1 of the present invention;
FIG. 5 is a basic connection diagram of a pretreatment system of a trace gas analyzing apparatus provided in example 2 of the present invention;
FIG. 6 is a schematic diagram of a first stage of a pretreatment process flow of a trace gas analysis apparatus provided in example 2 of the present invention;
FIG. 7 is a schematic diagram of a second stage of the pretreatment process flow of the trace gas analysis apparatus provided in example 2 of the present invention;
fig. 8 is a schematic diagram of a third stage of a pretreatment process flow of a trace gas analysis apparatus provided in example 2 of the present invention.
Detailed Description
The embodiment of the application provides a pretreatment system of trace gas analysis equipment and a using method thereof, and solves the technical problems of low temperature control precision, low trapping efficiency, poor separation effect and poor repeatability of detection results in the prior art.
In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the specific embodiments of the specification, it should be understood that the specific features mentioned in the embodiments and examples of the present invention are a detailed description of one representative of the technical solutions of the present application, and are not a limitation and a limitation of the technical solutions of the present application, and the technical features mentioned in the embodiments and examples of the present application may be combined with each other without conflict.
Example 1
As shown in fig. 1, a pretreatment system of a trace gas analysis device includes a trap a 1, a trap b2, a cold plate 3, a vacuum chamber 4, a valve set, a refrigeration system 6, a heating control system 7, a trap a control valve inlet 8, a trap a control valve outlet 9, a trap b control valve inlet 10, and a trap b control valve outlet 11; the valve group comprises a trap a control valve 5-1, a trap b control valve 5-2 and a transfer valve 5-3.
This will be explained in detail below.
The trapping trap a and the trapping trap b are fixed on the cold disc 3, the trapping trap a, the trapping trap b and the cold disc 3 are located in the vacuum bin 4, the cold disc 3 is connected with the refrigerating system 6, the trapping trap a and the trapping trap b are respectively connected with the valve group through gas pipelines, and the trapping trap a and the trapping trap b are respectively connected with the heating control system 7 through wires; constituting a dynamic system of temperature control.
That is to say, the cold plate 3 controlled by the refrigerating system 6 rapidly cools the trap closely contacted with the cold plate, so that the sample gas passing through the trap can be trapped, and the trap is directly connected with the heating control system 7, so that the sample can be desorbed by controlling the temperature rise, and then the sample is transferred and separated through the valve bank and the pipeline.
It should be noted that the number of trap in this embodiment 1 is 2, and the valve positions are switched to communicate with different pipelines by adjusting the temperature, so as to separate samples with different boiling points. The flexible and changeable arrangement avoids the defects that the single trap in the prior art can only be heated and separated once and has low separation degree. The cooperation of twin-well, separate earlier the concentration in trap b with the higher sample of part boiling point, the sample that heats alone in trap b sends to detecting, has kept apart trap a's interference, has avoided the influence of each other between the similar functional group, has greatly promoted the precision that the separation detected, has all promoted the accuracy of testing result from quantitative and qualitative angle.
On the other hand, the flexible and changeable pipeline not only isolates the interference between the two trapping traps, but also can introduce carrier gas from the outside to purge residual gas in the pipeline, thereby realizing the repeated consistency and stability of experimental results.
The valve block includes: a trap a control valve 5-1, a trap 2 control valve 5-2 and a transfer valve 5-3;
the transfer valve 5-3 is a multi-channel switching valve to communicate with different pipelines to realize different functions, and in this embodiment 1, the transfer valve has 6 sites, which are respectively communicated with a sample gas inlet, a carrier gas inlet, a trap a control valve inlet 8, a trap a control valve outlet 9, a trap b control valve inlet 10 and a gas outlet through gas pipelines; meanwhile, as an important transfer station, the gas becomes a link between the sample gas and the trap, and the carrier gas communicated with the sample gas is the power of the whole system, so that the transfer process is driven to be carried out smoothly.
The control valve 5-1 of the trap a is a multi-channel switching valve and is respectively communicated with the inlet of the trap a, the outlet of the trap a and the transfer valve 5-3 through gas pipelines; thereby controlling the communication and isolation state of the trap a.
The control valve 5-2 of the trap b is a multi-channel switching valve and is respectively communicated with an inlet of the trap b, an outlet of the trap b, the transfer valve 5-3 and an analysis system through gas pipelines; thereby controlling the communication and isolation state of the trap b.
It should be noted that, by adjusting the number of the transfer valves, a process flow of a complex pipeline can be realized, and in this embodiment 1, 1 transfer valve is provided, which is equivalent to a simple version, and thus, the process advancement is briefly and clearly embodied.
Furthermore, the control valve 5-2 of the trap b is connected with a carrier gas inlet through a gas pipeline, so that back flushing of the pipeline is facilitated, and residual interference gas in the pipeline is reduced; and is communicated with an analysis system interface to perform qualitative and quantitative analysis on the sample. Based on the pretreatment system shown in fig. 1, and particularly as shown in fig. 2 to 4, a method for treating a pretreatment system of a trace gas analysis device comprises the following three steps:
Generally, the low temperature of trap a is low enough, and is set to-150 ℃ in this embodiment, so that the sample to be tested can be stably stored.
Generally, the low temperature of trap b is the same as that of trap a, and is-150 ℃ in this example; the transition temperature of the trap a at this time was adjusted according to the number of transitions, and the transition temperatures of the two transitions were 50 ℃ in this example.
It should be noted that the purpose of the transfer in this embodiment is to heat and separate a part of the gas having a large difference in boiling point and having mutual interference between functional groups, and since the two trap traps are relatively independent and can control the temperature respectively, the independent and isolated operation can be realized, and the separated sample gas is sent to the trap b to be concentrated and to wait for detection.
Generally, the separation temperature of the trap b is not lower than 80 ℃, and in this embodiment, the separation temperature is set to 100 ℃, so that complete desorption of each species is ensured, and the accuracy of quantitative analysis is ensured.
It is worth to be noted that the traditional method has no transfer step, only comprises a pre-concentration and separation step, and heats and releases the enriched gas at one time to be sent to a detection system, thereby having great influence on qualitative and quantitative analysis.
Further, the processing method of the trace gas analysis equipment pretreatment system comprises 2 times or more than 2 times of transferring steps and separating steps; the embodiment sets up twice and shifts, separates the step, divides into two parts with the sample gas, tests respectively, has effectively avoided detecting the interference of ion to different species completely, and valve position switches can realize the isolation of trap and pipeline, sweeps, excludes the residual gas in the pipeline, has promoted precision, stability, the repeatability of testing result.
Further, the low temperature is not higher than-100 ℃; the trace gas species detected by the system is rich, the range of the boiling point is large, the range is from-180 ℃ to 80 ℃, the analysis result is not accurate for stably storing the sample, and the storage temperature is required to be lower than-100 ℃.
It is worth mentioning that the whole process is continuously and rapidly carried out, the temperature is rapidly reduced to the low temperature after one-time heating separation for waiting for the next transfer, the time consumption of the temperature reduction is not more than 5min, the heating is more rapid, the surge from the low temperature to the separation temperature can be realized within 2min basically, and the efficiency of the system is greatly improved.
Example 2
As shown in fig. 5, a pretreatment system of a trace gas analysis apparatus includes: the device comprises a trap a 12, a trap b 13, a cold plate 14, a vacuum bin 15, a valve group, a refrigerating system 17, a heating control system 18, a gas flow controller 19, a gas drier 20, a trap a control valve inlet 21, a trap a control valve outlet 22, a trap b control valve inlet 23 and a trap b control valve outlet 24; the valve group comprises a trap a control valve 16-1, a trap b control valve 16-2, a transfer valve 16-3 and a sample switching valve 16-4.
This will be explained in detail below.
The trapping trap a and the trapping trap b are fixed on the cold plate 14, the trapping trap a and the trapping trap b and the cold plate 14 are located in the vacuum bin 15, the cold plate 14 is connected with the refrigerating system 17, the trapping trap a and the trapping trap b are respectively connected with the valve group through gas pipelines, and the collecting trap a and the trapping trap b are respectively connected with the heating control system 18 through leads, so that a temperature-controlled dynamic system is formed.
That is to say, the cold plate 14 controlled by the refrigeration system 17 rapidly cools the trap closely contacted with the cold plate, so that the sample gas passing through the trap can be trapped, and the trap is directly connected with the heating control system 18, so that the sample can be desorbed by controlling the temperature rise, and then the sample is transferred and separated through the valve bank and the pipeline.
It should be noted that the number of trap in this embodiment 2 is 2, and the valve positions are switched to communicate with different pipelines by adjusting the temperature, so as to separate samples with different boiling points. The flexible and changeable arrangement avoids the defects that the single trap in the prior art can only be heated and separated once and has low separation degree. The cooperation of twin-well, separate earlier the concentration in trap b with the higher sample of part boiling point, the sample that heats alone in trap b sends to detecting, has kept apart trap a's interference, has avoided the influence of each other between the similar functional group, has greatly promoted the precision that the separation detected, has all promoted the accuracy of testing result from quantitative and qualitative angle.
On the other hand, the flexible and changeable pipeline not only isolates the interference between the two trapping traps, but also can introduce carrier gas from the outside to purge residual gas in the pipeline, so that the repeatability of the experimental result is consistent and stable.
The valve block includes: a trap a control valve 16-1, a trap b control valve 16-2 and a transfer valve 16-3;
the transfer valve 16-3 is a multi-channel switching valve to communicate with different pipelines to realize different functions, and in this embodiment 2, the transfer valve has 6 sites, which are respectively communicated with a sample gas inlet, a carrier gas inlet, a trap a control valve inlet 21, a trap a control valve outlet 22, a trap b control valve inlet 23 and a gas outlet through gas pipelines; meanwhile, as an important transfer station, the gas becomes a link between the sample gas and the trap, and the carrier gas communicated with the sample gas is the power of the whole system, so that the transfer process is driven to be carried out smoothly.
The trap a control valve 16-1 is a multi-channel switching valve and is respectively communicated with the trap a inlet, the trap a outlet and the transfer valve 16-3 through gas pipelines, so that the communication and isolation states of the trap a are controlled.
The trap b control valve 16-2 is a multi-channel switching valve and is respectively communicated with the trap b inlet, the trap b outlet, the transfer valve 16-3 and the gas outlet through gas pipelines, so that the communication and isolation states of the trap b are controlled.
It should be noted that, by adjusting the number of the transfer valves, a process flow of a complex pipeline can be realized, and in this embodiment 2, 1 transfer valve is provided, which is equivalent to a simple version, and thus, the process advancement is embodied simply and clearly.
Further, the valve block further comprises a sample switching valve 16-4; the sample switching valve 16-4 is a multi-position gate valve and is respectively connected with the plurality of sample gas inlets and the transfer valve 16-3; different sample gas advances the convenient blank test of going on of experiment and contrast test, provides the guarantee for the reliability of testing result.
It is worth to be noted that if the multi-position gate valve is not needed for sample injection, the single-gas-path sample injection can be realized.
It will be appreciated by those skilled in the art that when a sample switching valve is present, the sample gas first enters the sample switching valve and then enters the transfer valve; if there is no sample switching valve, the sample gas enters the transit valve directly.
Furthermore, the control valve 16-2 of the trap b is connected with a carrier gas inlet through a gas pipeline, so that back flushing of the pipeline is facilitated, and residual interference gas in the pipeline is reduced; and is communicated with an analysis system interface to perform qualitative and quantitative analysis on the sample.
Further, the pretreatment system of the trace gas analysis equipment comprises a gas flow controller 19, which is positioned on a pipeline where the transit valve 16-3 is communicated with the gas outlet and is used for monitoring the state of the system, conveniently and timely eliminating faults and avoiding the generation of faults.
Further, the pretreatment system of the trace gas analysis equipment is provided with a gas drier 20 which is positioned on a pipeline of the trap a control valve inlet communicated with the transfer valve 16-3 and a pipeline of the transfer valve 16-3 communicated with a sample gas inlet (sample switching valve); the dual dryer is arranged, so that the existence of water vapor is eliminated to the utmost extent, the damage of the water vapor to the equipment is reduced, the influence of heat consumed and generated in the water vapor gasification liquefaction process on the temperature control precision is avoided, and the interference and the influence on the detection result are reduced.
Based on the pretreatment system of example 2, and as shown in fig. 6-8, a method for treating a pretreatment system of a trace gas analyzer comprises the following three steps:
pre-concentration step: referring to fig. 6, the temperature of the trap a is set to be low, the sample gas sequentially passes through a first gas dryer 20, a transfer valve 16-3 and a second gas dryer 20 to remove most of water vapor, then sequentially passes through a trap a control valve inlet 21 and the trap a, is trapped by the trap a, and the gas which is not trapped passes through a trap a control valve outlet 22, then passes through the transfer valve 16-3 and a gas flow controller 19, and is discharged to a gas outlet. In order to improve the analysis accuracy of PPT level gas, pre-concentration is very critical, and buffering and preparation are also made for subsequent processes.
Generally, the low temperature of the trap a is low enough, and is set to-150 ℃ in this embodiment, so that the sample to be detected can be stably stored; the gas dryer reduces the interference of water vapor; the gas flow controller is arranged at the outlet, so that the total volume of the trapped sample gas can be detected, and the method has great significance for the results of sample injection flow monitoring, quantitative analysis and data comparison.
It is worth to be noted that the gas outlet can detect weak flow, which indicates that the gas path is smooth, the vacuum degree is good, and the large-scale water vapor condensation does not block the pipeline, which is a normal phenomenon, and is convenient for maintaining the system; if the flow is too large, the trapping efficiency of the trap is low, namely the cooling system or the trap is in failure, and the loss needs to be stopped in time.
Generally, the low temperature of trap b is the same as that of trap a, and is-150 ℃ in this example; the transition temperature of the trap a at this time was adjusted according to the number of transitions, and the transition temperatures of the two transitions were 50 ℃ in this example.
It should be noted that the purpose of the transfer in this embodiment is to heat and separate a part of the gas having a large difference in boiling point and having mutual interference between functional groups, and since the two trap traps are relatively independent and can control the temperature respectively, the independent and isolated operation can be realized, and the separated sample gas is sent to the trap b to be concentrated and to wait for detection.
On the other hand, the sample gas inlet stops sampling while transferring, so that new sample gas is prevented from being mixed, and interference is caused to transferring; meanwhile, the carrier gas is communicated with the control valve of the trap b, passes through the control valve of the trap b and is communicated with the analysis system, the pipeline at the section is purged, residual gas in the pipeline is removed, and the influence on next separation is prevented, so that the detection result is interfered.
Generally, the separation temperature of the trap b is not lower than 80 ℃, and in this embodiment, the separation temperature is set to 100 ℃, so that complete desorption of each species is ensured, and the accuracy of quantitative analysis is ensured.
It is worth to be noted that the traditional method has no transfer step, only comprises a pre-concentration and separation step, and heats and releases the enriched gas at one time to be sent to a detection system, thereby having great influence on qualitative and quantitative analysis.
On the other hand, when the separation is sent to an analysis system, the trap a controls the valve position of the valve 16-1 to change, so that the trap a is isolated, and the gas is prevented from entering and interfering the next trapping; meanwhile, the carrier gas passes through the transit valve 16-3 and the trap b control valve 16-2, and is continuously purged, so that residual gas in the pipeline is exhausted, and preparation is made for next detection.
It should be explained here that the carrier gas is an inert gas, which does not cause any interference or influence on gas analysis, and is mainly used as the power of a flow system to drive the sample gas to transfer, and then plays a role in purification to remove interfering components in the pipeline, thereby ensuring the accuracy of the detection result.
Further, the processing method of the trace gas analysis equipment pretreatment system comprises 2 times or more than 2 times of transferring steps and separating steps; the embodiment sets up twice and shifts, separates the step, divides into two parts with the sample gas, tests respectively, has effectively avoided detecting the interference of ion to different species completely, and valve position switches can realize the isolation of trap and pipeline, sweeps, excludes the residual gas in the pipeline, has promoted precision, stability, the repeatability of testing result.
Further, a trace gas analysis device pretreatment system, the low temperature being no higher than-100; the trace gas species detected by the system is rich, the range of the boiling point is large, the range is different from minus 180 ℃ to 80 ℃, the analysis result is not accurate due to leakage for stably storing the sample, and the storage temperature is required to be lower than minus 100 ℃.
It is worth mentioning that the whole process is continuously and rapidly carried out, the temperature is rapidly reduced to the low temperature after one-time heating separation for waiting for the next transfer, the time consumption of the temperature reduction is not more than 5min, the heating is more rapid, the surge from the low temperature to the separation temperature can be realized within 2min basically, and the efficiency of the system is greatly improved.
Finally, it should be noted that the above-mentioned embodiments are preferred embodiments of the present invention, and not restrictive to the technical solutions of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should be within the scope of the present invention.
Claims (9)
1. The pretreatment system of the trace gas analysis equipment is characterized by comprising a trap a, a trap b, a cold plate, a vacuum bin, a valve bank, a refrigeration system and a heating control system; the trapping trap a and the trapping trap b are fixed on the cold plate, the trapping trap a and the trapping trap b are located in the vacuum bin with the cold plate, the cold plate is connected with the refrigerating system, the trapping trap a and the trapping trap b are respectively connected with the valve group through gas pipelines, and the trapping trap a and the trapping trap b are respectively connected with the heating control system through wires.
2. The pretreatment system of a trace gas analysis apparatus according to claim 1, wherein the valve block comprises: a transfer valve, a trap a control valve and a trap b control valve; the transfer valve, the hydrazine a trapping control valve and the hydrazine b trapping control valve are all multi-channel switching valves;
the transfer valve is respectively communicated with a sample gas inlet, a carrier gas inlet, the trap a control valve outlet, the trap b control valve inlet and a gas outlet through gas pipelines;
the trap a control valve is respectively communicated with the trap a inlet, the trap a outlet and the transfer valve through gas pipelines;
the trap b control valve is respectively communicated with the trap b inlet, the trap b outlet, the transfer valve and the analysis system through gas pipelines.
3. The pretreatment system of a trace gas analysis apparatus according to claim 1, wherein the valve block further comprises a sample switching valve; the sample switching valve is a multi-position selection valve and is respectively connected with the plurality of sample gas inlets and the transfer valve.
4. The pretreatment system of trace gas analysis equipment according to claim 2, wherein the trap b control valve is further communicated with a carrier gas inlet through a gas pipeline, so that back flushing of the pipeline is facilitated, and residual gas in the pipeline is reduced.
5. The pretreatment system of a trace gas analysis apparatus according to claim 2, wherein a gas flow controller is disposed on a pipeline of the transfer valve communicating with the gas outlet.
6. The pretreatment system of a trace gas analysis apparatus according to claim 2, wherein a gas dryer is disposed on a pipeline connecting the trap a inlet and the transfer valve, and a pipeline connecting the transfer valve and the sample gas inlet.
7. A method of processing the pre-processing system of the trace gas analysis device according to claim 1, comprising the following three steps:
pre-concentration step: the temperature of the trapping trap a is set to be low, the sample gas sequentially passes through the transfer valve, the trapping trap a control valve inlet and the trapping trap a and is trapped by the trapping trap a, and the gas which is not trapped passes through the trapping trap a control valve outlet, the transfer valve and the gas flow controller and is discharged to the gas outlet;
a transfer step: the temperature of the trapping trap b is set to be low, the temperature of the trapping trap a is set to be transfer temperature, carrier gas sequentially passes through the transfer valve, the inlet of the control valve of the trapping trap a and the trapping trap a, and the sample gas in the trapping trap a is driven to enter the trapping trap b through the outlet of the control valve of the trapping trap a, the transfer valve and the inlet of the control valve of the trapping trap b;
a separation step: the temperature of the trap b is set to be the separation temperature, and the carrier gas drives the sample gas in the trap b to pass through the trap b and the outlet of the trap b control valve to drive the gas to the interface of the analysis system.
8. The method for processing the pretreatment system for a trace gas analysis apparatus according to claim 7, comprising 2 or more than 2 times of the transferring step and the separating step.
9. The method of processing the pre-processing system of the trace gas analysis device according to claim 7, wherein the low temperature is less than-100 ℃.
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