CN100489535C - Method for continuously monitoring smoke discharge and the device - Google Patents

Abstract

A continuous monitoring method for flue gas emission, comprising the following steps: (1) The flue gas in the pipeline is transported to a heating gas chamber with heat after being sampled, and the concentration of at least one first type of gaseous component to be measured in the heating gas chamber is measured. concentration; (2) removing the moisture in the gas discharged from the heating gas chamber; (3) measuring the concentration of at least one gaseous component of the second type to be measured in the gas after removing the water. The invention also discloses a continuous monitoring device for flue gas emission, which includes a sampling device, a heating pipeline, a heating gas chamber, and a first measuring device. Both ends of the heating pipeline are connected to the sampling device and the heating gas chamber. The first measuring device Measure the concentration of at least one first type of measured gaseous component in the heating gas chamber; the flue gas emission continuous monitoring device also includes a pair of water removal devices for removing water from the gas discharged from the heating gas chamber and a water removal device installed in the water removal device. Downstream of the device is a second measuring device for measuring the concentration of at least one second type of gaseous component to be measured in the gaseous substance after water removal.

Description

Method and device for continuous monitoring of flue gas emission

【Technical field】

The invention relates to the field of continuous monitoring of flue gas, more specifically, to a method and device for continuous monitoring of flue gas emission.

The flue gas emission continuous monitoring device is a system for monitoring the pollution source of flue gas emission. At present, a widely used continuous monitoring device for flue gas emission includes a sampling device, a heating line, a heating gas chamber and a measuring device. After the flue gas in the chimney or pipe to be tested is sampled by the sampling device, it is passed to the heating gas chamber through the whole heating pipeline, and then the components of the gas in the heating gas chamber are measured by the measuring device, such as sulfur dioxide, nitrogen oxides, ammonia and concentration of hydrogen chloride etc. Measuring devices usually use non-spectral infrared analysis technology and Fourier transform infrared spectroscopy analysis technology to analyze the gas concentration. This type of analysis technology mainly has the following disadvantages: the non-spectral infrared analyzer needs to be equipped with a corresponding filter for each gas to be measured, the system is complex, it needs to use moving parts, the reliability is poor, and the non-spectral technology is used, and the measurement drift is large; The moving parts used in the Lie infrared spectrometer are expensive and have poor reliability; the middle and far infrared light source is used, it is difficult to use optical fiber to transmit the measurement beam, and the productivity and maintainability are poor.

Another commonly used continuous monitoring device for flue gas emission differs from the above-mentioned monitoring device in that it does not use a heating gas chamber but adds a condensate drainage pretreatment device; after the flue gas in the measured chimney or pipe is sampled by the sampling device, Through the whole heating pipeline, it leads to the condensate drainage pretreatment device to condense and remove water, and then send it to the analytical instrument to measure the concentration of each component to be measured. A flow meter is also installed in front of the analytical instrument, and the reading of the flow meter can be used to know whether the sampling device and the heating gas pipeline are blocked. However, this kind of flue gas emission continuous monitoring device has the following disadvantages: since ammonia, sulfur dioxide, hydrogen chloride and other gases in the flue gas are easily soluble in water, these gases in the measured flue gas will dissolve in condensed water, resulting in the measurement of these gases The concentration is smaller than the true value; especially when measuring the concentration of low-concentration water-soluble gases such as sulfur dioxide and ammonia, the error is very large. In addition, the condensate drainage pretreatment device of this continuous flue gas emission monitoring device uses a condenser, a flow meter and a peristaltic pump, which is costly and has poor reliability.

【Content of invention】

The technical problem to be solved by the present invention is to overcome the above-mentioned defects and provide a continuous monitoring method and device for flue gas emission with low cost, small measurement error, high reliability, good productivity and maintainability.

The present invention is achieved through the following technical solutions: The present invention discloses a continuous monitoring method for flue gas emission, which includes the following steps: (1) The flue gas in the pipeline is sampled and then transferred to the heating gas chamber with heat tracing, and the absorption spectrum technology is used to or Raman spectroscopy or fluorescence spectroscopy or electrochemical techniques or paramagnetic techniques to measure the concentration of at least one water-soluble gas or gaseous metal or gaseous metal compound in the heated gas chamber; Moisture in the gas; (3) Using absorption spectroscopy, Raman spectroscopy, fluorescence spectroscopy, electrochemical techniques or paramagnetic techniques to measure the concentration of at least one gas that is insoluble in water in the gas after water removal.

The gas soluble in water includes sulfur dioxide, sulfur trioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen fluoride.

The gaseous metals include zinc, lead or mercury, and the gaseous metal compounds include mercuric chloride or silver chloride.

There is also a filtering step before the step (3) to filter out solid/liquid particles in the flue gas.

The water removal method in the step (2) is condensation water removal.

A continuous monitoring device for flue gas emission, comprising a sampling device, a heating pipeline, a heating gas chamber, and a first measuring device, the two ends of the heating pipeline are connected to the sampling device and the heating gas chamber, characterized in that: The concentration of at least one water-soluble gas or gaseous metal or gaseous metal compound in the heating gas chamber; the continuous monitoring device for flue gas emission also includes a water removal device for removing water from the gas discharged from the heating gas chamber, And a second measuring device installed downstream of the dewatering device to measure the concentration of at least one water-insoluble gas in the gaseous substance after dewatering, the first measuring device and the second measuring device are respectively absorption spectrum or pull Mann spectroscopy or fluorescence spectroscopy or electrochemical or paramagnetic analysis devices.

The absorption spectrum device is a differential optical absorption spectrum analysis device, including a light source, an optical fiber, a spectroscopic device, a photoelectric converter, and a signal processor. The analysis device is connected to the heating gas chamber through an optical fiber, and the light emitted by the light source is led to the heating gas chamber through an optical fiber. After passing through the gas in the heated gas chamber, it is led to the spectroscopic device by the optical fiber to split the light, and then it is received by the photoelectric converter and sent to the signal processor for analysis.

The first measuring device is provided with an oxygen sensor, and the second measuring device is also provided with an oxygen sensor.

The water removal device includes a water removal tank or a filter.

The monitoring device also includes a sampling pump or a jet device for extracting smoke from the pipeline.

A pressure sensor is installed in front of the sampling pump or the jet device.

A temperature sensor for detecting the temperature of the gas in the gas chamber is also installed on the heating gas chamber.

Compared with the prior art, the present invention has the following advantages: 1. The measurement error is small and the precision is high. Since the flue gas in the pipeline is sampled and then heated to the gas chamber, the concentration of some water-soluble gases and/or some gaseous metals or gaseous metal compounds is measured. At this time, the water in the flue gas exists in the form of steam. , does not affect the measurement accuracy of water-soluble gases. Then, some water-soluble gases are removed through condensation and water removal, and some water-insoluble gases remain. At this time, the temperature is low, and it is convenient to use absorption spectroscopy or electrochemical methods to measure the gas concentration. 2. The system cost is low, saving the expensive condenser and reducing the cost. 3. The water content in the flue gas can be known through the readings of the front and rear oxygen sensors.

【Description of drawings】

Fig. 1 is a structural schematic diagram of a continuous monitoring device for flue gas emission.

Fig. 2 is a schematic structural diagram of the first measuring device.

Fig. 3 is a schematic structural diagram of the second measuring device.

Fig. 4 is a schematic flow chart of a continuous monitoring method for flue gas emission.

【Detailed ways】

Please refer to shown in Fig. 1, a kind of flue gas emission continuous monitoring device, comprises sampling device 2, heating pipeline 3, heating gas chamber 4, first measuring device 12, dewatering device (such as water tank 6,7, water storage tank 14 and filter 8) and the second measuring device 11, wherein both ends of the heating line 3 are connected to the sampling device 2 and the heating gas chamber 4, and the sampling device 2 is installed on the pipeline 1 to be tested, the After the flue gas in the pipeline 1 is sampled by the sampling device 2, it is connected to the heating gas chamber 4 through the heating pipeline 3 and the valve 13, and the heating gas chamber 4 and the valve 13 are installed in the heating box 5, and an oxygen Sensors and a temperature sensor (not shown) are installed in the heating gas chamber 4; the flue gas is discharged from the heating gas chamber 4; the flue gas passes through the water tanks 6, 7, the water storage tank 14 and the filter 8 condenses and removes the moisture in the flue gas, the water tank 6 is connected with the filter 8 through a gas pipe, and the water tank 6 is also connected with a pressure sensor 9; wherein, the filter 8 filters The solid/liquid particles in the flue gas are removed, and the exhausted gas is connected to the instrument cabinet through the gas pipe.

Please also refer to Fig. 1, Fig. 2 and shown in Fig. 3, described first measuring device 12 is installed in the meter cabinet, is a set of measuring device applying ultraviolet differential absorption spectroscopy technology, the measuring device of this ultraviolet differential absorption spectroscopy technology It works like this: the light sent by an ultraviolet light source such as a xenon lamp 120 is connected to one end of the heating gas chamber 4 through an optical fiber 123, passes through the gaseous components in the heating gas chamber 4 and then passes through another optical fiber 124 and the light receiving device 121 If the optical splitting device is connected to the photoelectric converter, the received light is split by the optical splitting device such as a grating, and then converted into an electrical signal by the photoelectric converter, and then the electrical signal is sent to the first signal processor 122 for analysis to obtain at least one first type The concentration of the gaseous component being measured. Described second measurement device 11 is installed in the instrument cabinet, is a set of measurement device that applies semiconductor laser absorption spectroscopy technology, and the measurement device of this application semiconductor laser absorption spectroscopy technology works like this: a light source such as the light that laser 110 sends passes through After passing through the gas, it is received by the photoelectric converter 111 and converted into an electrical signal, and then the electrical signal is sent to the second signal processor 112 for analysis and taking into account the temperature in the heated gas chamber 4, thereby measuring at least The concentration of a gaseous component of the second type to be measured. In addition, an oxygen sensor is also installed on the air pipe in the instrument cabinet. An air extraction pump 10 is installed on the air path between the filter 8 and the second measuring device 11 for extracting the flue gas in the pipeline 1 . Of course, a fluidic device installed behind the second measuring device 11 can also be used to achieve the same function, and this kind of replacement has been disclosed by the prior art in the industry, and will not be repeated here. After the flue gas is discharged from the instrument cabinet, it can also be passed into the gas pipeline or other analysis equipment.

Please also refer to Fig. 4, the present invention also discloses a method for continuous monitoring of flue gas emission, which mainly includes the following steps: (1) the flue gas in the pipeline is transported to the heating gas chamber with heat after being sampled, and measured (2) remove the moisture in the gas discharged from the heating gas chamber; (3) measure at least one of the second measured gaseous components in the gas after water removal Concentration of gaseous components.

Specifically to this embodiment, it is shown as the working process of the above-mentioned continuous monitoring device for flue gas discharge: after the flue gas in the measured pipeline 1 is sampled by the sampling device 2, it is passed to the heating gas chamber through the heating pipeline 3 4, the first measurement device 12 in the instrument cabinet measures the concentration of at least one first type of measured gaseous component in the heating gas chamber 4; the first type of measured gaseous component is mainly those If it is not measured in the heating gas chamber 4, its measurement results may be distorted gaseous components, such as some water-soluble gases such as ammonia, sulfur dioxide, sulfur trioxide, nitrogen dioxide, hydrogen chloride, hydrogen fluoride, and temperature reduction gaseous metals (such as zinc, lead or mercury, etc.) and gaseous metal compounds (such as mercuric chloride or silver chloride, etc.) whose concentration will change afterward; Oxygen content in the air; after the flue gas is discharged from the heating gas chamber 4, it passes through the water removal device such as the water tank 6,7, the water storage tank 14 and the filter 8, and removes moisture and some easily soluble in the flue gas. The gas of water is such as ammonia, sulfur dioxide, hydrogen chloride, hydrogen fluoride etc., and the pressure sensor 9 that is connected with described water tank 6 measures the pressure of gas at this time; Oxygen sensor is installed on the top to measure the oxygen content in the gas at this time; finally, the second measuring device 11 in the instrument cabinet measures the concentration of at least one second type of gaseous component to be measured in the gas after dehydration, such as carbon monoxide Wait for the concentration of some insoluble gases in water.

According to national standards, a set of flue gas emission continuous monitoring device also needs to measure the content of water in the flue gas. Here, the smoke can be obtained through the readings of the oxygen sensor in the heating gas chamber 4 and the oxygen sensor on the air pipe in the instrument cabinet. water content in the air.

It must be pointed out that the above-mentioned embodiment is only a non-limitative illustration of the present invention. For example, in the above-mentioned embodiment, the measurement method of the first and second measurement devices and the device used therefor are only a specific special case. Of course, the concentration of the first and second types of measured gaseous components can also be used Other absorption spectroscopy techniques or Raman spectroscopy techniques or fluorescence spectroscopy techniques or electrochemical techniques or paramagnetic techniques measurements. Correspondingly, the first measuring device and the second measuring device may respectively include Raman spectroscopy or fluorescence spectroscopy or electrochemical or paramagnetic analysis devices. As long as those skilled in the art make various modifications, replacements and changes to the present invention without departing from the spirit and scope of the present invention, they still belong to the protection scope of the present invention.

Claims (12)

1. a fume emission continuous monitoring method comprises the steps:

(1) flue gas in the pipeline accompanies heat transfer to arrive the heated air chamber after taking a sample again, uses absorption spectrum technology or Raman spectroscopy or fluorescence spectrum technology or electrochemical techniques or paramagnetic technologies to measure the indoor at least a gas soluble in water of heated air or gaseous metal or gaseous metal compound concentrations;

(2) remove the moisture of discharging from the heated air chamber the gas;

(3) use absorption spectrum technology or Raman spectroscopy or fluorescence spectrum technology or electrochemical techniques or paramagnetic technologies are measured at least a concentration that is insoluble in the gas of water in the back gas that dewaters.

2. fume emission continuous monitoring method as claimed in claim 1 is characterized in that: described gas soluble in water comprises sulphuric dioxide, sulfuric anhydride, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen fluoride.

3. fume emission continuous monitoring method as claimed in claim 1 is characterized in that: described gaseous metal comprises zinc, lead or mercury, and described gaseous metal compound comprises mercuric chloride or silver chloride.

4. fume emission continuous monitoring method as claimed in claim 1 is characterized in that: also have a filtration step before in described step (3), to filter out the liquid/solid particle in the flue gas.

5. fume emission continuous monitoring method as claimed in claim 1 is characterized in that: the mode of dewatering in the described step (2) is that condensation dewaters.

6. fume emission continuous monitoring device, comprise sampler, heat tracing pipe, heated air chamber, first measurement mechanism, the heat tracing pipe two ends connect sampler and heated air chamber, it is characterized in that: described first measurement mechanism is measured the indoor at least a gas soluble in water of heated air or gaseous metal or gaseous metal compound concentrations; Described fume emission continuous monitoring device also comprises one to discharge the de-watering apparatus that gas dewaters from described heated air chamber, and one be installed in de-watering apparatus measured downstream at least a in the gaseous material of back that dewater and be insoluble in second measurement mechanism of concentration of the gas of water, and described first measurement mechanism, second measurement mechanism are respectively absorption spectrum or Raman spectrum or fluorescence spectrum or galvanochemistry or paramagnetic analytical equipment.

7. fume emission continuous monitoring device as claimed in claim 6, it is characterized in that: described absorption spectrum device is a differential optical absorption spectroanalysis device, comprise light source, optical fiber, light-splitting device, photoelectric commutator, signal processor, analytical equipment links to each other with the heated air chamber by optical fiber, the light that light source sends causes the heated air chamber by optical fiber, cause the light-splitting device beam split by optical fiber again after passing the gas in the heated air chamber, received by photoelectric commutator afterwards and the analysis of feed signals processor.

8. fume emission continuous monitoring device as claimed in claim 6 is characterized in that: described first measurement mechanism is provided with an oxygen sensor, and described second measurement mechanism also is provided with an oxygen sensor.

9. fume emission continuous monitoring device as claimed in claim 6 is characterized in that: described de-watering apparatus comprises except that water pot or filtrator.

10. fume emission continuous monitoring device as claimed in claim 6 is characterized in that: also comprise the sampling pump or the fluidic device that are used to extract out flue gas in the pipeline.

11. fume emission continuous monitoring device as claimed in claim 10 is characterized in that: before described sampling pump or the fluidic device pressure transducer is installed.

12. fume emission continuous monitoring device as claimed in claim 6 is characterized in that: described heated air also is equipped with the temperature sensor that is used for detected gas chamber gas temperature on the chamber.

Images