CN2722243Y

CN2722243Y - Molybdenum converter of nitrogen oxide automatic monitor

Info

Publication number: CN2722243Y
Application number: CN 200420016507
Authority: CN
Inventors: 范朝; 王艳; 黄建辉; 张冬生
Original assignee: HEBEI SAILHERO HIGH-TECH Co Ltd
Current assignee: HEBEI SAILHERO HIGH-TECH Co Ltd
Priority date: 2004-06-29
Filing date: 2004-06-29
Publication date: 2005-08-31
Anticipated expiration: 2014-06-29

Abstract

The utility model provides a molybdenum converter of a nitrogen oxide automatic monitor used for solving the technical problem that the exhaust pipe of the molybdenum converter can be clogged easily, belonging to the technical field of the physical instrument, comprising a furnace body, a heating jacket, a heat-insulating layer, a casing, an air inlet pipe and an exhaust pipe. The air inlet pipe and the exhaust pipe are arranged in the furnace body, the heating jacket is coated at the outer wall of the furnace body, the outer side of the heating jacket is provided respectively with the heat-insulating layer and the casing, and molybdenum sheets are provided with intervals in the furnace body. The molybdenum converter is characterized in that a filtering net is arranged in the furnace body, the filtering net is arranged at the upper part of the molybdenum sheet, and the exhaust pipe is arranged on the filtering net. The utility model solves effectively the problem that the exhaust pipe is clogged easily by adopting the method that the filter net is added and an anti-clogging hole is arranged on the exhaust pipe, the service life of the converter can be improved, and the maintenance work capacity and the maintenance cost of the device can be reduced. The converter has the advantages of simple structure, easy operation and good anti-clogging performance, the conversion efficiency can be attained more than 96%, and the converter can be used in the automatic monitor with continuous operation.

Description

Molybdenum converter of nitrogen oxide automatic monitor

Technical Field

The utility model relates to a molybdenum converter used for realizing conversion from nitrogen dioxide to nitric oxide in a measuring instrument, in particular to a nitrogen oxide automatic monitor, which belongs to the technical field of physical instruments.

Background

Nitrogen dioxide is a toxic, reddish-brown gas, a major pollutant component in ambient air, and an important factor in causing acid rain. In recent years, with the increasing awareness of environmental protection, the content of harmful gases in air and the control thereof are more and more important, and thus the demand for monitoring technology is also increasing. The chemical analysis method is a commonly adopted monitoring method at present, has the defects of low detection precision, more consumables, large workload, difficulty in completing real-time monitoring and the like, and is gradually replaced by an advanced chemiluminescence method, and the principle of the method is as follows: according to Nitric Oxide (NO) and excess ozone (O)₃) React to form excited nitrogen dioxide (NO)₂ ^*) The concentration of NO is obtained by detecting the luminous intensity of the excited nitrogen dioxide molecule by the principle that the emission of photons releases excess energy back to a low energy state, and the luminous intensity is proportional to the concentration of NO. Due to nitrogen dioxide (NO)₂) Not in contact with O₃Reaction takes place with NO₂The monitoring is carried out by reducing the NO present in the sample gas stream by molybdenum at 315 deg.C₂The sample gas flow passes through a molybdenum converter and then enters a reaction chamber, and the concentration of total nitrogen oxides (NOx) in the air is measured by an automatic monitor. The concentration of NOx and NO is subtracted to obtain NO₂The concentration of (c). From the above process, it can be seen that the molybdenum converter is an important component of an automatic monitor. In the use process of the existing molybdenum converter, a gas discharge channel is blocked due to tiny particles generated by friction between gas and molybdenum sheets, so that the service life of the molybdenum converter is influenced, and the maintenance of equipment is increasedAnd debugging the workload.

Disclosure of Invention

The utility model discloses the technical problem that will solve is: overcomes the defects of the prior art and provides a molybdenum converter of an automatic nitrogen oxide monitor, which has the function of gas filtration and is not easy to block.

The utility model discloses the title problem is solved by following technical scheme:

the utility model provides a nitrogen oxide automatic monitoring appearance molybdenum converter, includes furnace body, heating jacket, heat preservation, casing and intake pipe, blast pipe in the constitution, wherein intake pipe, blast pipe setting in the furnace body and access to outside the furnace body, the heating jacket cladding is the heat preservation, casing outward in proper order, and the molybdenum piece is placed to the interval in the furnace body, and its special character is: and a metal filter screen is arranged in the furnace body, the filter screen is positioned at the upper part of the molybdenum sheet, and the exhaust pipe is positioned above the filter screen.

In the molybdenum converter of the automatic nitrogen oxide monitor, a plurality of air holes are distributed on the air inlet end of the exhaust pipe.

Above-mentioned nitrogen oxide automatic monitoring appearance molybdenum converter, the export of intake pipe is located the filter screen lower part and is close to furnace bottom position to make the sample gas fully contact with the molybdenum piece.

The utility model overcomes the shortcoming that current molybdenum converter gas discharge pipeline easily takes place to block up adopts to add the filter screen and sets up the method of preventing stifled bleeder vent on gas discharge pipe, has effectively solved the easy problem of blockking up of blast pipe to improve the life of molybdenum converter from this, reduced the maintenance work volume and the maintenance cost of equipment. The design structure is simple, the implementation is easy, the anti-blocking performance is good, the conversion efficiency can reach more than 96%, and the device is suitable for automatic monitoring instruments which run continuously.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

FIG. 2 is an enlarged partial view of the exhaust pipe;

FIG. 3 is a schematic diagram of the gas path of the automatic detector for nitrogen oxides.

The reference numbers for the various components in the figures refer to the following: 1. heating a jacket; 2. a housing; 3. a heat-insulating layer; 4. a platinum resistor; 5. an air inlet pipe; 6. an exhaust pipe; 6-1, air holes and 7, molybdenum sheets; 8. filtering with a screen; 9. a furnace body; 10. a particle filter; 11. a molybdenum converter; NO/NO_XA conversion valve; 13. an automatic zero valve; 14. a reaction chamber; 15. a photomultiplier tube; 16. a data processing unit; 17. a display; 18. an ozone generator; 19. an ozone scrubber; 20. and (4) a pump.

Detailed Description

Referring to fig. 3, the operation principle of the automatic nitrogen oxide monitor is as follows: the sample gas passes through a particle filter 10, one path of the sample gas enters a molybdenum converter 11, is converted and then enters an NO/NOx conversion valve 12, the other path of the sample gas directly enters the NO/NOx conversion valve, the NO/NOx conversion valve acts once every four seconds, the sample gas does not enter a reaction chamber 14 through the molybdenum converter when power is off, the measured value is NO, the sample gas enters the reaction chamber through the molybdenum converter when power is on, and the molybdenum converter converts NO in the air₂Conversion to NO, plus the original NO in the sample gas, NOx is measured, and the difference between the concentrations of the two is NO₂The value of (c). The automatic zero valve 13 is operated once every 5 sampling periods (5 × 4 ═ 20 seconds), and when it is energized, the sample gas is directly discharged from the automatic zero valve without passing through the reaction chamber, and at this time, only O is present in the reaction chamber₃The gas, but not the sample gas to be measured, therefore, there is no chemical reaction in the reaction chamber, the photomultiplier 15 outputs only the dark current of the multiplier tube, and the current value is recorded as the automatic zero point of the instrument. The data processing unit 16 performs data processing on the measured photoelectric signals, and the display 18 displays the detection result. The reacted gas passes through an ozone scrubber 19, and the residual ozone is removed and discharged by a pump 20.

As can be seen from the above measurement process, the utility model discloses an important part in the automatic nitrogen oxide monitor. Referring to fig. 1, the utility model comprises a furnace body 9, a heating jacket 1, a heat preservation layer 3, a shell 2, an air inlet pipe 5, an exhaust pipe 6 and a filter screen 8. The air inlet pipe 5 and the exhaust pipe 6 are arranged in the furnace body 9, the heating jacket is coated on the outer wall of the furnace body, a heat preservation layer and a shell are sequentially arranged outside the heating jacket, molybdenum sheets 7 are placed in the furnace body at intervals, the filter screen 8 is positioned on the upper portions of the molybdenum sheets, and the filter screen is made of stainless steel materials. Referring to fig. 2, the exhaust pipe 6 is positioned above the filter screen, and a plurality of air holes 6-1 are distributed on the air inlet end of the exhaust pipe. The upper part of the furnace body is also provided with a platinum resistor 4 for measuring the temperature of the furnace. The shell is made of stainless steel materials, and fastening screws are arranged at the bottom of the shell. The outlet end of the air inlet pipe 5 is arranged at the bottom of the furnace body, so that the gas entering the furnace body from the air inlet pipe can fully contact and completely react with the molybdenum sheet 7 from the bottom in a high-temperature state, and is discharged from the exhaust pipe after being filtered by the filter screen 8. The molybdenum sheet is at the reaction process, and the friction of gas and molybdenum sheet can produce some tiny particle thing, and these tiny particle thing can get into the blast pipe along with gas to take place the blast pipe and block up, influence monitoring instrument's normal work, set up the filter screen and can filter these particulate matters, the blast pipe inlet end sets up the bleeder vent and then can further prevent to block up and make the increase of exhaust flow area, and it is smooth and easy to exhaust.

The working process of the utility model is as follows: the heating jacket heats the furnace body to 315 +/-5 ℃ under the control of an external temperature control component, the sample gas enters the bottom of the furnace body through the gas inlet pipe and is fully contacted with a large number of molybdenum sheets which are irregularly shaped and are arranged at intervals in the furnace body, and NO in the sample gas is converted into NO through the activated molybdenum sheets under the high-temperature state₂All reduced to NO, the reaction formula is: and the reacted gas is discharged through a filter screen and an exhaust pipe. After the molybdenum converter is used for a period of time, the conversion rate of the molybdenum is reduced, and pure hydrogen can be introduced into the furnace body for regeneration so as to recover the conversion efficiency of the molybdenum converter.

Claims

1. The utility model provides a nitrogen oxide automatic monitoring appearance molybdenum converter, includes furnace body, heating jacket, heat preservation, casing and intake pipe, blast pipe in the constitution, wherein intake pipe, blast pipe are placed in the furnace body and are access to outside the furnace body, and the heating jacket cladding is the heat preservation, casing outward in proper order, and molybdenum piece, its characterized in that are placed to the interval in the furnace body at the heating jacket: a metal filter screen (8) is arranged in the furnace body, the filter screen is positioned at the upper part of the molybdenum sheet (7), and the exhaust pipe (6) is positioned above the filter screen.

2. The automatic nitrogen oxide detector molybdenum converter of claim 1, wherein: a plurality of air holes (6-1) are distributed on the air inlet end of the exhaust pipe (6).

3. The nitrogen oxide automonitor molybdenum converter according to claim 2, wherein: and the outlet of the air inlet pipe (5) is positioned at the lower part of the filter screen and is close to the bottom of the furnace body.