JP4553050B2 - Method and apparatus for measuring exhaust gas odor of cement manufacturing facility - Google Patents

Description

  The present invention relates to a method for continuously measuring an odor in exhaust gas generated in a cement manufacturing facility and an exhaust gas odor measuring apparatus.

  Raw materials for cement production are composed of natural inorganic materials such as limestone, clay, silica, and iron oxide raw materials. However, in recent years, various industrial wastes have come to be used as a part of cement raw material or cement burning fuel for disposal. This industrial waste contains waste plastics, soil containing oil and cleaning agents, and various sludges. As a result, carbon and organic components that do not originate from coal are generated. It was. Since the exhaust gas generated by volatilization from these industrial wastes or their combustion contains odorous substances, it must be managed.

  In this case, there are two types of legal regulations regarding odors, the odor control law, which measures odors based on the concentration of specific malodorous substances, and those based on odor index, but most odors are various low-concentration substances. Therefore, the odor index standard is more realistic than measuring the specific malodorous substance concentration. The odor index is a numerical value calculated from the dilution factor (odor concentration) when the sample is diluted with odorless air until the subject who is confirmed to have normal olfaction feels no odor. Is measured by human olfaction.

  Generally, a semiconductor sensor is well known as a sensor for measuring odor. This semiconductor sensor utilizes the fact that the resistance value of the semiconductor changes due to adsorption of odorous molecules on the semiconductor surface, but in principle, because it is a gas sensor that detects a specific single substance, it remains as it is. Therefore, it is difficult to distinguish a complex odor mixed with various odorous substances like human olfaction.

For this reason, conventionally, for example, as in the odor measuring apparatus described in Patent Document 1, a plurality of semiconductor sensors are used so as to be sensitive to different odors. The correspondence between human and sensibility data for various odors is constructed in a neural network, and the odor can be expressed by human sense while detecting with a semiconductor sensor.
JP 2006-275862 A

However, the semiconductor sensor uses a phenomenon in which the oxide semiconductor that is the sensor element reacts by adsorbing the reducing gas, and there is no problem when the odorous substance is made of the reducing gas. Causes a negative error. About 98% of odorous substances are reducing gases, but the exhaust gas generated in cement production facilities contains oxidizing gases such as nitrogen oxides (NOx) and sulfur oxides (SOx). It is difficult to accurately measure the odor in the exhaust gas of a cement manufacturing facility using such a semiconductor sensor.
On the other hand, if the odor index is directly measured by the three-point comparison odor bag method, it is necessary to sample the gas and secure the subject every time it is measured, and continuous measurement is impossible.

  Therefore, the present applicant previously measured the total amount of hydrocarbons in the exhaust gas generated from the cement production facility as “exhaust gas odor measurement method and measurement device of cement production facility” in Japanese Patent Application No. 2008-36066, A technique for estimating the odor index of exhaust gas from the total hydrocarbon content was proposed. With this technology, it has become possible to grasp the odor continuously. However, depending on the cement manufacturing equipment, there may be an irritating odor in addition to a burning odor due to organic substances in the odor of the exhaust gas. In some cases, measurement of the amount of hydrogen alone was insufficient.

  The present invention has been made in view of such circumstances, and provides a measurement method and a measurement apparatus that continuously measure odors of various exhaust gases from cement manufacturing facilities and enable accurate management by an odor index. The purpose is to do.

As odor components of exhaust gas generated in cement manufacturing facilities, there are cases where irritating odors may be felt in addition to organic odors caused by industrial waste as described above. There is a need to. As an organic matter odor, the odor can be measured by measuring the amount of total hydrocarbon (Total HydroCarbon: abbreviated as THC for short) proposed in the previous application.
On the other hand, as odorous substances other than organic substances, nitrogen dioxide (NO ₂ ) in nitrogen oxides (NOx) can be considered, but most of the nitrogen oxides in the gas discharged from the cement manufacturing facility are odorless nitrogen monoxide. (NO), and it does not make sense to measure this. The present inventor has found that nitric oxide reacts with oxygen in the atmosphere and changes to nitrogen dioxide while repeating the measurement by the odor bag method. In other words, most of the nitrogen oxides in the exhaust gas immediately after generation is odorless nitrogen monoxide, but when it is released into the atmosphere and changes to the odorous substance nitrogen dioxide after a predetermined time, this causes an irritating odor. is there. This nitrogen dioxide is formed by reacting nitrogen monoxide in exhaust gas nitrogen oxides with the atmosphere, so even if nitrogen monoxide is reduced, the amount of nitrogen dioxide increases and the number of moles does not change. Therefore, the amount of nitrogen dioxide can be derived from the initial amount of nitric oxide.

Under such knowledge, the method for measuring exhaust gas odor of a cement production facility according to the present invention continuously measures the total hydrocarbon amount and the amount of nitrogen oxide in the exhaust gas generated from the cement production facility. The amount of nitrogen dioxide after a predetermined time is estimated from the measured value, and the odor index of exhaust gas is estimated from the amount of nitrogen dioxide and the total amount of hydrocarbons.

  That is, the nitrogen oxides in the exhaust gas are substantially nitric oxide and nitrogen dioxide. Of these, the amount of nitrogen dioxide after a predetermined time is equal to the initial amount of nitrogen dioxide existing at the time of exhaust gas generation after a predetermined time. The amount is the sum of the amount of nitrogen dioxide produced by the reaction of nitric oxide. From nitric oxide to nitrogen dioxide is a reaction with oxygen present in a large amount in the atmosphere, and proceeds within a predetermined time. The amount of nitrogen dioxide after a predetermined time can be estimated from the reaction rate. Then, the odor index is estimated from the estimated value of the nitrogen dioxide amount after the predetermined time and the measured value of the total hydrocarbon amount as the organic substance amount.

In the exhaust gas odor measurement method according to the present invention, at least a nitrogen monoxide amount may be measured as the nitrogen oxide amount.
That is, the nitrogen oxides in the exhaust gas are mostly nitric oxide and nitrogen dioxide, but in the initial stage, the amount of nitrogen dioxide is very small and most of it is nitric oxide, and the nitric oxide changes to nitrogen dioxide after a predetermined time. , Will account for the majority of the total amount of nitrogen dioxide. Therefore, even if the amount of nitrogen dioxide is estimated from the initial amount of nitric oxide, the estimated value of the odor index does not change greatly and is sufficient in practical use. Of course, the initial amount of nitrogen dioxide may also be measured, and the amount of nitrogen dioxide may be estimated by adding the amount of nitrogen dioxide that changes after a predetermined time from nitric oxide.

Further, in the exhaust gas odor measurement method according to the present invention, the peak portion of the change is corrected or excluded from the measurement result of the total hydrocarbon amount in the exhaust gas, and the exhaust gas odor is calculated using the total hydrocarbon amount after the correction or exclusion. An index may be estimated.
That is, when the measured value of the total hydrocarbon amount changes suddenly and a peak portion is generated, it is due to the operating condition such as combustion and not due to the amount of organic matter having an odor. Therefore, the odor index is estimated using the total hydrocarbon amount after correcting or excluding this peak portion.

When this correction or exclusion is performed, the total hydrocarbon amount after the correction or exclusion is obtained by continuously measuring the amount of a specific gas of either carbon monoxide or oxygen in the exhaust gas. It is preferable that the peak portion of the change in the total hydrocarbon amount generated corresponding to the occurrence of the change peak portion is corrected or excluded .

If the measured value of the total hydrocarbon amount changes abruptly, it is considered to be due to the operating condition such as combustion as described above. As a physical quantity that changes depending on the combustion status, the amount of either specific gas of carbon monoxide or oxygen is measured simultaneously, and the measured value of this specific gas eliminates the influence of peak changes caused by the combustion status. By correcting or excluding the measured value of the amount, the odor index is estimated from the total hydrocarbon amount after the correction or exclusion , and the amount of organic matter is accurately determined without being affected by changes in the operating conditions such as combustion. Can be measured.

As a method of correction or exclusion , when a peak portion is generated in the measured value of the specific gas and a peak portion is also generated in the measured value of the total hydrocarbon amount corresponding to the occurrence, the entire peak portion is generated. Methods such as estimating the odor index from the measurement value excluding the peak portion of the measurement value of the hydrocarbon amount, or estimating the odor index from the measurement value obtained by multiplying the measurement value of the peak portion by a specific coefficient Can be adopted. Alternatively, the measurement value of the total hydrocarbon amount may always be corrected at a constant ratio by the measurement value of the specific gas measured at the same timing. For carbon monoxide and oxygen, the former has a positive correlation with the total hydrocarbon amount, and the latter has a negative correlation with the total hydrocarbon amount.

Further, in the exhaust gas odor measuring method according to the present invention, the threshold values of the total hydrocarbon amount and the nitrogen dioxide amount are set in advance, respectively, and the estimated value of the odor index is calculated from the total hydrocarbon amount and the nitrogen dioxide amount. Regarding the relational expression for obtaining, when the total hydrocarbon amount is above the threshold value and the nitrogen dioxide amount is less than the threshold value, and when the total hydrocarbon amount is less than the threshold value and the nitrogen dioxide amount is above the threshold value, The total hydrocarbon amount and the nitrogen dioxide amount are both set to be equal to or greater than the threshold value, and based on the total hydrocarbon amount and the nitrogen dioxide amount, any one of the three types of relational expressions is set. The odor index should be estimated based on this.
When estimating the odor index from the total amount of hydrocarbons and the amount of nitrogen dioxide, if any of the components is large, the odor index due to human sensory tends to be biased, and this is reflected to reflect this. More accurate estimation of the odor index becomes possible by changing the relational expression for estimating the odor index.

  The exhaust gas odor measuring apparatus for a cement production facility according to the present invention is provided with a sampling unit for extracting a part of the exhaust gas in a pipe for transferring the exhaust gas from the cement kiln. A total hydrocarbon amount measuring device that measures the amount of hydrocarbons, a nitrogen oxide amount measuring device that measures the amount of nitrogen oxides in exhaust gas, and a nitrogen dioxide amount after a predetermined time are estimated from the measurement results of the nitrogen oxide amount measuring device A nitrogen dioxide amount estimating means; and an odor index estimating means for estimating an odor index of exhaust gas from the nitrogen dioxide amount estimated by the nitrogen dioxide amount estimating means and the total hydrocarbon amount measured by the total hydrocarbon amount measuring device. It is provided.

In that case, the nitrogen oxide amount measuring device may measure at least the amount of nitric oxide.
In addition, the sampling unit includes a specific gas amount measuring device for measuring the amount of any one of carbon monoxide and oxygen in the exhaust gas, and the total hydrocarbon amount measuring device based on the measurement value of the specific gas amount measuring device. and correcting or exclude means a measurement of the is provided, the odor index estimating means, as to estimate the odor index with total hydrocarbon amount after correction or excluded by the correction or exclude means Also good.
Further, the odor index estimation means is configured to set a threshold value for the total hydrocarbon amount and the nitrogen dioxide amount, respectively, and to obtain an estimated value of the odor index from the total hydrocarbon amount and the nitrogen dioxide amount. Regarding the relational expression, the total hydrocarbon amount is above the threshold value and the nitrogen dioxide amount is less than the threshold value, the total hydrocarbon amount is less than the threshold value and the nitrogen dioxide amount is above the threshold value, and the total carbonization amount is Three types are set, both when the amount of hydrogen and the amount of nitrogen dioxide are equal to or greater than the threshold, and the odor index is calculated based on one of the above three types of relations based on the total amount of hydrocarbons and the amount of nitrogen dioxide It may be estimated.

  According to the exhaust gas odor measuring method and measuring apparatus for a cement production facility according to the present invention, the amount of nitrogen dioxide after a predetermined time has been estimated from the amount of nitrogen oxides in the exhaust gas, and the odor is determined from the amount of nitrogen dioxide and the total amount of hydrocarbons. By estimating the index, it is possible to estimate the odor index of various exhaust gases combined with irritating odors and burnt odors from cement production facilities. The subsequent odor index can be estimated, and an accurate odor index consistent with the actual sensory can be continuously estimated.

  Hereinafter, an embodiment of an exhaust gas odor measuring method and measuring apparatus for a cement manufacturing facility according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a cement production facility equipped with an exhaust gas odor measuring apparatus according to an embodiment. A cement manufacturing facility 1 shown in FIG. 1 includes a raw material mill and a dryer 2 for pulverizing and drying cement raw materials, a preheater 3 for preheating powder raw materials obtained by the raw material mill, and a powder preheated by the preheater 3. A kiln 4 for firing the raw material, a cooling machine (not shown) for cooling the cement clinker after firing in the kiln 4 and the like are provided.

  The kiln 4 heats and sinters the cement raw material supplied from the preheater 3 to 1450 ° C. or higher with a burner while rotating a horizontal cylindrical shell to generate a cement clinker. In this case, the exhaust gas from the kiln 4 is introduced into the raw material mill and the dryer 2 via the preheater 3, and the raw material mill and the dryer 2 are introduced by introducing the exhaust gas from the kiln 4, Cement raw materials are pulverized and dried simultaneously. The preheater 3 is a multi-stage cyclone type in which a plurality of cyclones are connected in multiple stages from below to above, and the cement raw material crushed by the raw material mill is preheated to a predetermined temperature using the exhaust gas from the kiln 4. To do.

  In this cement production facility 1, the cement raw material is a mixture of limestone, clay, silica, iron oxide raw material and the like in an appropriate ratio, but industrial waste including waste plastic, oil, detergent, etc. Containing soil, various sludges, incineration ash, etc. are used as part of cement raw material or part of kiln fuel. In FIG. 1, double solid arrows indicate the flow of obtaining cement clinker from cement raw material.

  On the other hand, the flow of the exhaust gas generated by the combustion in the kiln 4 is shown by a broken line. After being used as a heat source for drying in the mill and dryer 2, it is sent to the dust collector 5, and after dust is removed by the dust collector 5, it is discharged from the chimney 6 to the atmosphere.

  The dust collector 5 is an electric dust collector that collects dust in exhaust gas by using static electricity generated by high voltage discharge, for example, and dust such as ash mixed as solids in the exhaust gas is collected at the electrode. Is done. In addition to the electric dust collector, a known dust collector such as a bag filter or a cyclone can be used as long as it can collect a solid content in the exhaust gas. The collected dust is input to the raw material mill through the dust delivery pipe 7.

  An exhaust gas odor measuring device 11 is provided between the dust collector 5 and the chimney 6. In the exhaust gas odor measuring apparatus 11, a sampling section 13 for extracting a part of exhaust gas is provided in a pipe 12 between the dust collector 5 and the chimney 6, and the total hydrocarbon amount measuring device 14 and the sampling section 13 are provided. The carbon monoxide amount measuring device 15 for measuring the amount of carbon monoxide as the specific gas and the nitrogen oxide amount measuring device 16 are connected in parallel, and the total hydrocarbon amount measuring device 14 is connected to the measured value of the total hydrocarbon amount. Is connected to the total hydrocarbon amount correction means 17 for correcting the amount of carbon dioxide with the measured value of the carbon monoxide amount, and the nitrogen oxide amount measuring means 16 estimates the nitrogen dioxide amount after a predetermined time from the nitrogen oxide amount. 18 is connected to the total hydrocarbon amount correcting means 17 and the nitrogen dioxide amount estimating means 18 to estimate the odor index of the exhaust gas from the corrected total hydrocarbon amount and the estimated amount of nitrogen dioxide after a predetermined time. Is configured to monitor 20 to display the time course of vapor index estimating means 19 and the odor intensity index by chart or the like is connected.

  The total hydrocarbon amount measuring device 14 is, for example, a measuring device using a hydrogen ionization detector (FID). By sending and igniting exhaust gas and hydrogen of fuel from a nozzle, the organic matter in the exhaust gas is converted into a hydrogen flame. It measures the ionic current due to carbon ions that are burned in and generated between the collector electrodes that sandwich the flame.

  The carbon monoxide amount measuring device 15 is a measuring device based on, for example, a non-dispersive infrared analysis method, and utilizes the property that carbon monoxide selectively absorbs infrared light having a specific wavelength. The component concentration is measured from the amount of infrared absorption.

  The total hydrocarbon amount measuring device 14 and the carbon monoxide amount measuring device 15 continuously measure the total hydrocarbon amount and the carbon monoxide amount of the exhaust gas at the same timing. The total hydrocarbon amount correcting means 17 corrects the total hydrocarbon amount continuously measured by the total hydrocarbon amount measuring device 14 by the carbon monoxide amount measured at the same timing.

On the other hand, the nitrogen oxide amount measuring device 16 is a measuring device by a chemiluminescence method, for example, which measures the amount of nitric oxide from the intensity of chemiluminescence by reaction with ozone. Nitrogen dioxide is also converted into nitric oxide. Measured.
Further, the nitrogen dioxide amount estimation means 18 reacts with oxygen after a predetermined time has elapsed from the release of nitrogen monoxide to the atmosphere among the nitrogen monoxide amount and the nitrogen dioxide amount measured by the nitrogen oxide amount measuring device 16. Assuming that it changes to nitrogen dioxide, the amount of nitrogen dioxide after the lapse of the predetermined time is estimated, and the initial amount of nitrogen dioxide measured by the nitrogen oxide amount measuring device 16 reacts with the nitric oxide after the lapse of the predetermined time. This is the sum of the amount of nitrogen dioxide produced.

  The odor index estimating means 19 preliminarily formulates and stores the total hydrocarbon amount and the correlation between the nitrogen dioxide amount and the odor index in a computer, and the corrected total carbonization obtained from the total hydrocarbon quantity correcting means 17. From the hydrogen amount and the estimated value of the nitrogen dioxide amount obtained from the nitrogen dioxide amount estimating means 18, the odor index is estimated according to these relational expressions.

This odor index was measured by olfactory measurement method (method of calculating odor index and odor emission intensity), and the sample was diluted with odorless air until the subject who passed the test of normal olfaction did not feel odor. It is a numerical value obtained by calculating the dilution ratio (odor concentration) and multiplying the common logarithm value by 10. The calculation formula is expressed as odor index = 10 × Log (odor concentration). As a specific method of measurement, the “three-point comparison odor bag method” is adopted. In this three-point comparison odor bag method, odorless air is put in two of the three bags, and a sample diluted to a predetermined dilution factor is put in the remaining one bag. Is a method in which six or more subjects repeat the process of determining the presence or absence of odor in each bag while changing the dilution factor, and obtain the dilution factor at which no odor is felt.

  Further, the odor index and the total hydrocarbon amount and nitrogen dioxide amount have a relationship of odor index = a × log (b × total hydrocarbon amount + c × nitrogen dioxide amount + d), and are constants thereof. “a” to “d” vary depending on the type of waste and fuel, and are obtained in advance by pilot operation or the like. Three types of relational expressions are set as will be described later.

  The method of measuring the odor of the exhaust gas from the cement manufacturing facility 1 by the exhaust gas odor measuring device 11 configured as described above will be described. However, a part of the exhaust gas is sampled by the sampling unit 13 between the dust collector 5 and the chimney 6, and the total hydrocarbon amount measuring device 14, the carbon monoxide amount measuring device 15, and the nitrogen oxide amount measuring device 16. Thus, the total hydrocarbon amount, carbon monoxide amount and nitrogen oxide amount (nitrogen monoxide amount and nitrogen dioxide amount) are continuously measured.

Among these, for the total amount of hydrocarbons, when the total amount of hydrocarbons in the exhaust gas is continuously measured, the measured value rises and falls according to the amount of organic matter contained in the exhaust gas. FIG. 2 is a chart showing the result of continuous measurement of the total amount of hydrocarbons by adding a clay-based waste such as sludge used as clay in the raw material to the cement raw material at a constant rate. In the figure, a thin line indicates a case where an industrial waste containing an organic substance is input at a certain rate, and a thick line indicates a case where the input is not performed. As shown in FIG. 2, the total amount of hydrocarbons in the exhaust gas increases due to the presence of industrial waste, and if the input amount is not changed, a peak that is considered to be due to combustion appears. It turns out that it has been moving at an almost constant baseline. This indicates that there is a correlation between the amount of waste input and the total amount of hydrocarbons in the exhaust gas.

In addition, the total hydrocarbon amount and the carbon monoxide amount show the same behavior during continuous measurement, and when a peak part occurs on one side, the peak part tends to occur on the other side at the same timing. The peak part of the carbon amount is caused by incomplete combustion, and not caused by the amount of the organic substance introduced. Therefore, if the peak portion is generated in the total hydrocarbon amount at the same timing as the generation of the peak portion of the carbon monoxide amount, the peak portion of the total hydrocarbon amount is generated due to the influence of combustion. It is thought that there is.

FIG. 3 shows the result of continuously measuring the amount of oxygen (O ₂ ) and carbon monoxide (CO) together with the total amount of hydrocarbons in the exhaust gas. From FIG. 3, it is understood that the peak portion of the change in the total hydrocarbon amount and the peak portion of the change in the carbon monoxide amount occur at substantially the same timing, and both have a positive correlation. it can. In other words, the total amount of hydrocarbons in the exhaust gas is on the baseline if the combustion in the kiln is sufficient, and becomes a peak when organic matter is generated due to poor combustion and incomplete combustion. It shows that it appears. In addition, the oxygen amount shows a change opposite to the change of the carbon monoxide amount, and has a negative correlation with the total hydrocarbon amount.

  FIG. 4 shows the results of measuring the odor index by sampling the peak portion of the total hydrocarbon amount at the time of occurrence of the peak and the baseline portion, and the ■ mark is the measured value at the time of occurrence of the peak portion. The mark is the measured value at the baseline. FIG. 4 shows that the measured value when the peak portion of the total hydrocarbon amount is generated has no correlation with the odor index. That is, when the total amount of hydrocarbons is continuously measured, the odor index can be managed using only the measurement value at the baseline without considering the measurement value at the time of occurrence of the peak portion.

5 and 6 are scatter diagrams showing the correlation between the total hydrocarbon amount and the odor index. In FIG. 5, the measured value when the peak portion of the total hydrocarbon amount is included is also shown. In FIG. 6, the measurement value when the peak portion is generated is excluded. Although the approximate equation curves are also shown, it can be seen that FIG. 6 is more applicable. That is, accurate estimation can be performed by estimating the odor index based only on the measured value of the total hydrocarbon amount that affects the odor, excluding the measured value when the peak portion is generated.
In FIGS. 5 and 6, in order to see the correlation between the total hydrocarbon amount and the odor index, the exhaust gas having a small amount of nitrogen oxide is used.

Therefore, in the next total hydrocarbon amount correcting means 17, when a peak portion occurs in the measured value of the carbon monoxide amount, a peak portion occurs in the measured value of the total hydrocarbon amount at the timing when the peak portion occurs. If the peak value is also generated at the same timing in the measured value of the total hydrocarbon amount, the next odor index estimation means is excluded with the peak portion of the total hydrocarbon amount excluded. The measured value is transferred to 17. Therefore, the measurement value of the total hydrocarbon amount output from the total hydrocarbon amount correcting means 17 is in a state in which changes due to the combustion state are excluded.

On the other hand, the nitrogen oxide amount measuring device 16 continuously measures the nitrogen oxide amount in the exhaust gas, and based on the measurement result, the nitrogen dioxide amount estimating means 18 estimates the nitrogen dioxide amount after a predetermined time has elapsed.
Explaining this method for estimating the amount of nitrogen dioxide, FIG. 7 shows the results of examining the change over time in the gas composition in the collection bag after collecting the exhaust gas, and the composition changes greatly in a short time after collecting the exhaust gas. I understand. Immediately after collecting the exhaust gas, the nitrogen monoxide concentration (amount) was higher than the nitrogen dioxide concentration (amount), but after 60 minutes, the nitrogen dioxide concentration increased. This is because nitric oxide reacted with oxygen in the atmosphere and changed to nitrogen dioxide. In this case, since the total amount (concentration) of nitrogen oxides does not change, the nitrogen dioxide concentration after 60 minutes is the result of the reaction of nitrogen monoxide with oxygen in the atmosphere to the initial nitrogen dioxide concentration. The increased nitrogen dioxide concentration is added. In addition, after 60 minutes, the change is almost stable with a minute amount, and the subsequent minute change is considered not to affect the odor fluctuation. Therefore, the amount of nitrogen dioxide was estimated with a predetermined time of 60 minutes.

In that case, in the reaction rate equation v = k [NO] [O ₂ ], since oxygen is present in the atmosphere, it is overwhelmingly larger than the amount of nitric oxide, and [O ₂ ] >> [ NO], so the nitric oxide concentration after t seconds is

It is represented by Here, v is the reaction rate, k is the rate constant, [] indicates the concentration, and [] ₀ indicates the initial concentration.
In order to obtain after 60 minutes, t = 3600 seconds, and the rate constant k is, for example, k = 0.004 in the exhaust gas from an actual cement production facility. If these are substituted, the estimation formula of the nitrogen dioxide concentration after 60 minutes Is as follows.

Then, the odor index estimation means 19 estimates the odor index from the nitrogen dioxide amount estimated by the equation (2) and the total hydrocarbon quantity corrected by the total hydrocarbon quantity correction means 17. In this odor index estimation, all hydrocarbons corresponding to burnt odor and nitrogen dioxide corresponding to pungent odor have different odor components, so the sensory test by the three-point comparison odor bag method in actual cement production equipment When the above is performed, the result tends to be biased between the case where these odors are close to each other and the compound odor in which any of these odors strongly appears. This is thought to be because when the total amount of hydrocarbons is low, the influence of nitrogen dioxide becomes relatively large, and the odor changes from a burning odor to an irritating odor, resulting in a difference in individual sensitivity. On the other hand, when the amount of nitrogen dioxide is low, the influence of all hydrocarbons increases, and it is considered that a burning odor is strongly felt.

Therefore, the estimation method is changed between the case where both the total hydrocarbon amount and the nitrogen dioxide amount affect the odor, and the case where one of them is small.
Specifically, threshold values are set for the total hydrocarbon amount and the nitrogen dioxide amount, respectively, and when any one of these components is less than the threshold value (when each odor is recognized) And the estimation formula was calculated | required by pilot operation etc. about three types, when both are above a threshold value (in the case of compound odor). As the threshold value, for example, the total hydrocarbon amount is set to 22 ppm, and the nitrogen dioxide amount is set to 30 ppm.

As an estimation formula of the odor index, (a) when both the total hydrocarbon amount and the nitrogen dioxide amount are equal to or greater than the respective threshold values, (b) when the total hydrocarbon amount is less than the threshold value (22 ppm), (c) In the case where the amount of nitrogen dioxide was less than the threshold value (30 ppm), it was determined as follows.
(A) Odor index = 10 × LOG (192 × THC amount + 23 × NO ₂ amount−5952)
(B) Odor index = 10 × LOG (−471 × THC amount + 25 × NO ₂ amount + 8812)
(C) Odor index = 10 × LOG (530 × THC amount + 2433 × NO ₂ amount−47793)
FIG. 8 shows the correlation between the odor index estimated based on these estimation formulas and the actually estimated index. FIG. 8A, FIG. 8B, and FIG. (A), (b), and (c) correspond to each other. In addition, the shape of the plot (◯ Δ □ × +) in the figure indicates the installation location of the target cement production facility.
As shown in FIG. 8, it is within the range of about ± 2, and can be estimated with a probability of about 99%.

As is clear from the above explanation, by capturing both the odor caused by organic matter and the odor caused by nitrogen dioxide, the odor index of various exhaust gases combined with irritating odors and burnt odors from cement production facilities can be obtained. In this case, since the odor is estimated by measuring the total hydrocarbon amount and the nitrogen oxide amount, the odor index can be continuously estimated.
In addition, the total hydrocarbon amount is corrected only to the total hydrocarbon amount according to the amount of organic matter because the peak value due to the operating state such as combustion is excluded in the total hydrocarbon amount correcting means 17, Regarding the amount of nitrogen dioxide, the amount after a predetermined time has elapsed is estimated from the exhaust gas immediately after generation, and the odor index can be accurately estimated based on the corrected total hydrocarbon amount and the estimated amount of nitrogen dioxide. it can.
In addition, in the estimation, taking into account the difference in human sensitivity between the case of a complex odor and the case of being close to a single odor, the odor index is calculated by three types of relational expressions divided into these cases. Therefore, an extremely accurate odor index can be obtained.

  On the other hand, by continuously measuring the amount of carbon monoxide, the combustion state of the kiln 4 can be grasped based on the change in the measured value of the amount of carbon monoxide. That is, if the peak portion frequently occurs in the amount of carbon monoxide, it indicates that incomplete combustion is continuing, and measures such as correcting the operating conditions of the kiln 4 by monitoring this measured value. be able to. In this case, as described above, the measured value of the amount of carbon monoxide and the measured value of the total amount of hydrocarbons before correction show a correlation, so instead of monitoring the measured value of the amount of carbon monoxide, By monitoring the measured value of the total hydrocarbon amount before correction, the combustion state of the cement kiln 4 can be grasped from the peak portion occurrence state.

  In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the measurement value of the total hydrocarbon amount is corrected from the measurement value of the carbon monoxide amount, but instead of this carbon monoxide amount, the oxygen amount is continuously measured, and the oxygen amount The measured value of the total hydrocarbon amount may be corrected from the measured value of, and the odor index may be estimated from the corrected total hydrocarbon amount. In the case of this oxygen amount, as shown in FIG. 3, the characteristics opposite to those of carbon monoxide are shown. Therefore, when correcting the measured value of the total hydrocarbon amount from the measured value of this oxygen amount, What is necessary is just to correct | amend as what has a negative correlation. Moreover, when measuring this oxygen amount, it is possible to grasp | ascertain the combustion condition of a kiln from the measured value similarly to the case of the amount of carbon monoxide.

  When measuring the amount of carbon monoxide and the amount of oxygen, the exhaust gas sampled from the sampling unit for measuring the total hydrocarbon amount was measured in the above embodiment, but at the outlet of the preheater separately from the sampling unit. A sampling unit may be attached and can respond quickly to changes.

  When correcting the total hydrocarbon amount, in the above embodiment, the peak portion of the total hydrocarbon amount generated at the same timing as the peak portion of the measured value of the carbon monoxide amount (or oxygen amount) is excluded. However, it may be corrected so as to relax the peak portion by multiplying the measured value of the peak portion by a specific coefficient, or all the measured values of the total hydrocarbon amount are measured at the same timing. You may make it correct | amend by a fixed ratio always by the measured value of the specific gas of either carbon or oxygen.

  Furthermore, in the estimation of the amount of nitrogen dioxide, the initial amount of nitrogen dioxide at the time of exhaust gas generation (at the time of sampling) and the amount of nitrogen dioxide whose initial nitric oxide changes after the lapse of a predetermined time are added together. Since the amount of nitrogen is small, only the amount of nitrogen dioxide estimated from the amount of nitrogen monoxide may be used. Although the predetermined time is 60 minutes, it is practically sufficient to estimate the amount of nitrogen dioxide after at least 30 minutes.

It is a whole system lineblock diagram showing the cement manufacturing equipment provided with one embodiment of the exhaust gas odor measuring device concerning the present invention. It is a chart which shows the continuous measurement result of the total hydrocarbon amount in waste gas. It is a chart which shows the result of having measured the total amount of hydrocarbons in exhaust gas, the amount of oxygen, and the amount of carbon monoxide continuously. It is a scatter diagram which shows the correlation with each measured value at the time of peak part generation | occurrence | production at the time of baseline, and an odor index | exponent about the total hydrocarbon amount in waste gas. It is a scatter diagram which shows the correlation with all the measured values including the peak part of the total hydrocarbon amount in waste gas, and an odor index. It is a scatter diagram which shows the correlation with the measured value except the peak part of the total amount of hydrocarbons in waste gas, and an odor index. It is a graph which shows the time-dependent change of the amount of nitrogen oxides in a waste gas, the amount of nitric oxide, and the amount of nitrogen dioxide. It is a scatter diagram showing the relationship between the estimated odor index and the measured odor index, when (a) is high in both the total hydrocarbon amount and nitrogen dioxide amount, (b) when the nitrogen dioxide amount is high and the total hydrocarbon amount is low, (C) shows the case where the total amount of hydrocarbons is high and the amount of nitrogen dioxide is low.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cement production equipment 2 Raw material mill and dryer 3 Preheater 4 Kiln 5 Dust collector 6 Chimney 11 Exhaust gas odor measuring device 12 Pipe 13 Sampling part 14 Total hydrocarbon measuring device 15 Carbon monoxide measuring device (specific gas measuring device)
16 Nitrogen oxide measuring device 17 Total hydrocarbon amount correcting means 18 Nitrogen dioxide amount estimating means 19 Odor index estimating means 20 Monitor

Claims (9)

  The total amount of hydrocarbons and nitrogen oxides in the exhaust gas generated from the cement production facility are continuously measured, and the amount of nitrogen dioxide after a predetermined time is estimated from the measured value of the amount of nitrogen oxides. An exhaust gas odor measuring method for a cement manufacturing facility, wherein an odor index of exhaust gas is estimated from a total hydrocarbon amount.   The method for measuring exhaust gas odor in a cement production facility according to claim 1, wherein at least a nitrogen monoxide amount is measured as the nitrogen oxide amount. 2. The peak portion of the change is corrected or excluded from the measurement result of the total hydrocarbon amount in the exhaust gas, and the odor index of the exhaust gas is estimated using the total hydrocarbon amount after the correction or exclusion. Or the exhaust gas odor measuring method of the cement manufacturing facility of 2. The total amount of hydrocarbons after correction or exclusion corresponds to the occurrence of a peak portion of the change in the amount of the specific gas by continuously measuring the amount of the specific gas of either carbon monoxide or oxygen in the exhaust gas. The exhaust gas odor measurement method for a cement production facility according to claim 3, wherein the peak portion of the change in the total hydrocarbon amount generated is corrected or excluded .   A threshold for total hydrocarbon amount and nitrogen dioxide amount is set in advance, and a relational expression for obtaining an estimated value of the odor index from the total hydrocarbon amount and the nitrogen dioxide amount is as follows. Both when the amount of nitrogen dioxide is below the threshold and above the threshold, when the total hydrocarbon amount is below the threshold and the nitrogen dioxide amount is above the threshold, and both the total hydrocarbon amount and nitrogen dioxide amount Is set to three types when the value is equal to or greater than a threshold value, and the odor index is estimated based on any one of the above three types based on the total hydrocarbon amount and nitrogen dioxide amount. The exhaust gas odor measuring method for a cement production facility according to any one of claims 1 to 4.   The pipe for transferring the exhaust gas from the cement kiln is provided with a sampling unit for extracting a part of the exhaust gas, and the sampling unit includes a total hydrocarbon amount measuring device for measuring the total hydrocarbon amount in the exhaust gas, A nitrogen oxide amount measuring device for measuring the amount of nitrogen oxide in the sample, a nitrogen dioxide amount estimating means for estimating a nitrogen dioxide amount after a predetermined time from the measurement result of the nitrogen oxide amount measuring device, and the nitrogen dioxide amount estimating means And an odor index estimating means for estimating an odor index of the exhaust gas from the total hydrocarbon amount measured by the nitrogen dioxide amount and the total hydrocarbon amount measuring device. apparatus.   The exhaust gas odor measuring device for a cement manufacturing apparatus according to claim 6, wherein the nitrogen oxide content measuring device measures at least the amount of nitric oxide. In the sampling unit, a specific gas amount measuring device that measures the amount of specific gas of either carbon monoxide or oxygen in the exhaust gas, and measurement of the total hydrocarbon amount measuring device by the measurement value of the specific gas amount measuring device and correcting or exclude means the value is provided, the odor index estimating means, and characterized by estimating the odor index with total hydrocarbon amount after correction or excluded by the correction or exclude means An exhaust gas odor measuring apparatus for a cement manufacturing apparatus according to claim 6 or 7,   The odor index estimating means is a relational expression for obtaining an estimated value of the odor index from the total hydrocarbon amount and the nitrogen dioxide amount, respectively, while threshold values for the total hydrocarbon amount and the nitrogen dioxide amount are respectively set. When the total hydrocarbon amount is greater than or equal to the threshold value and the nitrogen dioxide amount is less than the threshold value, the total hydrocarbon amount is less than the threshold value and the nitrogen dioxide amount is greater than or equal to the threshold value, and the total hydrocarbon amount And the amount of nitrogen dioxide are both set to the threshold value or more, and the odor index is estimated based on any of the above three types of relations based on the total amount of hydrocarbons and the amount of nitrogen dioxide. The exhaust gas odor measuring apparatus for a cement production facility according to any one of claims 6 to 8, wherein

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