Methane and non-methane total hydrocarbon on-line monitoring device

Abstract

The utility model discloses a methane and non-methane total hydrocarbon on-line monitoring device which comprises a fourteen-way valve, the fourteen-way valve is provided with fourteen ports, the first port is connected with sample gas, the second port is communicated with the ninth port, a quantitative loop is connected between the third port and the fourteenth port, the fourth port is connected with the twelfth port, and the twelfth port is communicated with the twelfth port. A PQ column is connected in a connecting passage, a sixth interface is connected with a first carrier gas, an enrichment pipe is connected between a seventh interface and a tenth interface, an eighth interface is connected with an MFC mass flow meter, the MFC mass flow meter is externally connected with a vacuum pump, an eleventh interface is connected with a detector, and a thirteenth interface is connected with a second carrier gas. The device disclosed by the utility model realizes on-line monitoring of the content of methane and non-methane total hydrocarbon in ambient air under the condition of normal temperature, is simple to operate, realizes sampling through switching of the single multi-way sample injection valve, and simultaneously performs cycle work of sample injection of the non-methane total hydrocarbon, so that the analysis period and the cost are effectively reduced.

Description

Technical Field

[0001] The utility model relates to a pollution source gas monitoring technology, in particular to an online monitoring device for methane and non-methane total hydrocarbons. Background Art

[0002] Non-methane total hydrocarbons refer to the general term for all hydrocarbons except methane, mainly including alkanes, olefins, aromatic hydrocarbons and oxygen-containing hydrocarbons. It is the sum of other gaseous organic compounds except methane that respond on the hydrogen flame ionization detector under the conditions specified in the HJ38 standard (the result is calculated in carbon).

[0003] The main method for detecting non-methane total hydrocarbons is to detect the content of total hydrocarbons and methane respectively through gas chromatography, and the content of non-methane total hydrocarbons can be obtained by subtraction. The existing method in the industry uses concentrated sampling to achieve direct measurement, but the analysis time is long, roughly 10-15 minutes, which can no longer meet the requirements of rapid monitoring. Utility Model Content

[0004] In order to solve the above-mentioned deficiencies in the prior art, the purpose of the utility model is to provide an online monitoring device for methane and non-methane total hydrocarbons, which can quickly monitor methane and non-methane online to meet the requirements of rapid monitoring.

[0005] The utility model adopts the following technical solution to solve the technical problem: an online monitoring device for methane and non-methane total hydrocarbons, comprising a fourteen-way valve, wherein the fourteen-way valve has fourteen interfaces, wherein the first interface is connected to the sample gas, the second interface is communicated with the ninth interface, the third interface is connected to the fourteenth interface with a quantitative loop, the fourth interface is connected to the twelfth interface, and a PQ column is connected in the connecting passage, the sixth interface is connected to the first carrier gas, the seventh interface is connected to the tenth interface with an enrichment tube, the eighth interface is connected to an MFC mass flowmeter, the MFC mass flowmeter is externally connected to a vacuum pump, the eleventh interface is connected to a detector, and the thirteenth interface is connected to a second carrier gas.

[0006] Optionally, the fourteen-way valve has a methane sampling analysis and non-methane total hydrocarbon enrichment state, a sampling and non-methane total hydrocarbon sampling state.

[0007] Optionally, when the fourteen-way valve is in the methane sampling analysis and non-methane total hydrocarbon enrichment state, the first interface of the fourteen-way valve is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, the seventh interface is connected to the eighth interface, the ninth interface is connected to the tenth interface, the eleventh interface is connected to the twelfth interface, and the thirteenth interface is connected to the fourteenth interface.

[0008] Optionally, when the fourteen-way valve is in the sampling and non-methane total hydrocarbon injection state, the first interface of the fourteen-way valve is connected to the fourteenth interface, the second interface is connected to the third interface, the fourth interface is connected to the fifth interface, the sixth interface is connected to the seventh interface, the eighth interface is connected to the ninth interface, the tenth interface is connected to the eleventh interface, and the twelfth interface is connected to the thirteenth interface.

[0009] By adopting the above technical scheme, the utility model realizes the online monitoring of the content of methane and non-methane total hydrocarbons in ambient air under normal temperature conditions. The operation is simple, and the cyclic work of sampling and injection of non-methane total hydrocarbons is realized by switching a single multi-way injection valve, which effectively reduces the analysis cycle and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a connection diagram of the fourteen-way valve of the utility model in the first state;

[0011] Figure 2 It is a connection schematic diagram of the fourteen-way valve of the utility model in the second state. DETAILED DESCRIPTION

[0012] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It is also necessary to explain that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings.

[0013] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0014] like Figure 1 and Figure 2 As shown, the utility model discloses an online monitoring device for methane and non-methane total hydrocarbons, which includes a fourteen-way valve 100, and the fourteen-way valve 100 has fourteen interfaces. In the fourteen-way valve 100, the first interface is connected to the sample gas, the second interface is connected to the ninth interface, the third interface is connected to the fourteenth interface, the quantitative ring 200 is connected between the third interface and the fourteenth interface, the fourth interface is connected to the twelfth interface, and the PQ column 300 is connected in the connecting passage, the sixth interface is connected to the first carrier gas, the seventh interface and the tenth interface are connected to the enrichment tube 400, the eighth interface is connected to the MFC mass flowmeter 500, the MFC mass flowmeter 500 is externally connected to the vacuum pump 600, the eleventh interface is connected to the detector 700, and the thirteenth interface is connected to the second carrier gas. Among them, the first interface to the fourteenth interface of the fourteen-way valve are distributed in a clockwise direction.

[0015] Since the fourteen-way valve 100 can switch its state through its own switching valve, in the present invention, the fourteen-way valve 100 has two states: methane sampling analysis and non-methane total hydrocarbon enrichment state (first state) and sampling and non-methane total hydrocarbon sampling state (second state).

[0016] When the fourteen-way valve 100 is in the first state, the first interface of the fourteen-way valve 100 is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, the seventh interface is connected to the eighth interface, the ninth interface is connected to the tenth interface, the eleventh interface is connected to the twelfth interface, and the thirteenth interface is connected to the fourteenth interface. In this state, the enrichment pipe 400 is cooled to minus 10 degrees Celsius, and the sample gas, under the power of the vacuum pump 600, sequentially passes through the first interface, the second interface, the ninth interface, and the tenth interface of the fourteen-way valve 100 to enter the enrichment pipe 400. At this time, non-methane total hydrocarbons are enriched in the enrichment pipe 400, and the sample gas then passes through the seventh interface and the eighth interface of the fourteen-way valve to the MFC mass flowmeter 500 in sequence, and the sampling is stopped after reaching the set flow rate. At the same time, the second carrier gas passes through the thirteenth interface, the fourteenth interface, the quantitative ring 200, the third interface, the fourth interface of the fourteen-way valve, and the PQ column 300 in sequence, and then the methane separated from the PQ column is sent to the detector 700 through the twelfth interface and the eleventh interface for analysis and measurement.

[0017] When the fourteen-way valve 100 is in the second state, the first interface of the fourteen-way valve 100 is connected to the fourteenth interface, the second interface is connected to the third interface, the fourth interface is connected to the fifth interface, the sixth interface is connected to the seventh interface, the eighth interface is connected to the ninth interface, the tenth interface is connected to the eleventh interface, and the twelfth interface is connected to the thirteenth interface. In this state, the enrichment tube 400 is heated to desorb the non-methane total hydrocarbons, and at the same time, the first carrier gas is reversely purged through the sixth interface and the seventh interface of the fourteen-way valve 100 to purge the enrichment tube 400, so that the non-methane total hydrocarbons in the enrichment tube 400 are discharged from the tenth interface and the eleventh interface of the fourteen-way valve 100 and enter the detector 700 for analysis and measurement. At the same time, the sample gas passes through the first interface and the fourteenth interface of the fourteen-way valve 100 in sequence under the power of the vacuum pump 600 and enters the quantitative ring 200.

[0018] In one embodiment of the present invention, the quantitative ring 200 is a 1L quantitative ring, the detector 700 is a hydrogen flame ionization detector, and the fourteen-way valve 100 is a pneumatic valve.

[0019] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the utility model. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other to form a technical solution.

[0020] Except for the technical features described in the specification, the other technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present utility model, the other technical features will not be described in detail here.

Claims

1. An online monitoring device for methane and non-methane total hydrocarbons, characterized in that: The invention comprises a fourteen-way valve, wherein the fourteen-way valve has fourteen interfaces, wherein the first interface is connected to the sample gas, the second interface is connected to the ninth interface, the third interface is connected to the fourteenth interface with a quantitative loop, the fourth interface is connected to the twelfth interface, and a PQ column is connected in the connecting passage, the sixth interface is connected to the first carrier gas, the seventh interface is connected to the tenth interface with an enrichment tube, the eighth interface is connected to the MFC mass flowmeter, the MFC mass flowmeter is externally connected to a vacuum pump, the eleventh interface is connected to the detector, and the thirteenth interface is connected to the second carrier gas.

2. The on-line monitoring device for methane and non-methane total hydrocarbons according to claim 1, characterized in that: The fourteen-way valve has a methane sampling analysis and non-methane total hydrocarbon enrichment state, a sampling and non-methane total hydrocarbon sampling state.

3. The on-line monitoring device for methane and non-methane total hydrocarbons according to claim 2, characterized in that: When the fourteen-way valve is in the methane sampling analysis and non-methane total hydrocarbon enrichment state, the first interface of the fourteen-way valve is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, the seventh interface is connected to the eighth interface, the ninth interface is connected to the tenth interface, the eleventh interface is connected to the twelfth interface, and the thirteenth interface is connected to the fourteenth interface.

4. The on-line monitoring device for methane and non-methane total hydrocarbons according to claim 2, characterized in that: When the fourteen-way valve is in the sampling and non-methane total hydrocarbon injection state, the first interface of the fourteen-way valve is connected to the fourteenth interface, the second interface is connected to the third interface, the fourth interface is connected to the fifth interface, the sixth interface is connected to the seventh interface, the eighth interface is connected to the ninth interface, the tenth interface is connected to the eleventh interface, and the twelfth interface is connected to the thirteenth interface.

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