JP5347551B2 - High temperature deposit control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of easily and accurately determining the adhesion tendency of an adhesive material in high temperature gas on the spot, and to provide a method capable of properly performing the injection control of a deposit suppressing agent on the basis of decision results. <P>SOLUTION: An adherend 1 for allowing the material in the high temperature gas to adhere is inserted in the high temperature gas within a furnace or flue and the adhesion tendency of a deposit is determined on the basis of the adhesion state of the deposit to the adherend 1. The addition amount of the deposit suppressing agent is controlled on the basis of the adhesion state. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention, which adhesion substances contained in the hot gas in the furnace or flue can determine a tendency to adhere to the boiler tubes and the like, based on the determine the constant result of this to control the addition amount of the high-temperature deposit control agent About.

  Many problems have been confirmed so far, such as a decrease in the heat recovery rate of the boiler, shutdown due to blockage of the water pipe, and corrosion of the water pipe due to high-temperature deposits such as the waste heat boiler water pipe.

  As a method for suppressing the adhesion of high-temperature deposits, for example, a method for suppressing high-temperature deposits by adding Si, Al, Zr-based chemicals to the fuel is known (Japanese Patent No. 3746026, etc.).

  However, the adhesion suppression effect by these high-temperature deposit suppressants may vary depending on the components of the deposit, the amount of adhesive components scattered in the flue, etc. There is.

  The adhesion suppression effect of the high-temperature deposit suppressant is judged by visual inspection when the furnace operation is stopped, the differential pressure increase rate in the flue, and the decrease in the amount of steam generated in the boiler, etc. At the time when the adverse effect due to is confirmed, a strong deposit has already grown, and the increase or decrease in the amount of drug injected alone cannot sufficiently exert the adhesion suppression effect.

  There are exhaust gas sampling methods such as JIS Z 8808 and various simple exhaust gas sampling devices (Japanese Patent Application Laid-Open No. 2004-61484, etc.) as methods for collecting scattered dust in a flue in a short period of time. It is a method of drawing dust together. These methods add cooling effects from the outside air when taken from the flue, but the actual growth of hot deposits in the flue is also affected by the time of exposure to the exhaust gas, and Since the properties and temperature gradient cannot be reproduced by drawing dust to the outside air, these methods cannot accurately determine the tendency of high-temperature deposits.

Japanese Patent No. 3746026 JP 2004-61484 A

  As described above, with conventional anti-adhesion technology using high-temperature deposit inhibitors, the amount of deposit is determined by visual inspection when the furnace is stopped, the differential pressure increase rate in the flue, and the amount of steam generated in the boiler, etc. is reduced. Therefore, at this point in time, strong deposits have already grown, and it is not possible to sufficiently exert the adhesion suppression effect only by increasing / decreasing the amount of drug injection, or the operating conditions of the furnace, the deposit properties caused by the fuel Since it is not possible to switch the drug specification in accordance with the fluctuation, it is difficult to appropriately control the injection amount of the high-temperature deposit inhibitor.

The present invention is described above solves the conventional problems, easily and determined accurately in situ adhesion tendency of adherent substances in the hot gas, suitably the injection control of deposit control agent based on the determination result an object of the present invention is to provide a way that can be done.

The high-temperature deposit control method according to claim 1, wherein a tubular adherend for adhering a substance in the gas is inserted into a high-temperature gas in a furnace or flue, and the deposit adhered to the adherend. A high-temperature deposit control method for controlling the addition amount of a high-temperature deposit inhibitor added to a high-temperature gas based on the adhesion amount of the adherend and the temperature of the adherend, and coating weight to obtain a calibration curve of the temperature of the該被wear body, is characterized in controlling the amount of hot deposit inhibitor according to calibration curve.

According to a second aspect of the present invention, there is provided a method for suppressing high-temperature deposits according to the first aspect, wherein the adherend is inserted into the high-temperature gas in the furnace or the flue at different insertion times for obtaining the calibration curve. in each time, the temperature of the該被deposition body was measured at the predetermined insertion time has elapsed, then, pull the該被adherend from the furnace in or flue, the deposits adhering to the adherend The adhesion amount is measured, and the calibration curve is created from these measurement results.

According to a third aspect of the present invention, there is provided a method for suppressing high-temperature deposits according to claim 1 or 2, wherein a chemical injection point for adding a high-temperature deposit inhibitor to the furnace or the flue in the high-temperature gas in the furnace or the flue is provided. provided, the place adherend downstream of the drug injection point of the furnace or the flue, on the basis of the calibration curve, the high temperature as temperature of the該被adhesive body is a predetermined temperature The amount of the deposit inhibitor is controlled.

The method for suppressing high-temperature deposits according to claim 4 is the method according to claim 1 or 2, wherein a chemical injection point for adding a high-temperature deposit inhibitor to the furnace or the flue is added to the high-temperature gas in the furnace or the flue. provided, the place adherend on the upstream side of the drug injection point of the furnace or the flue, on the basis of the calibration curve, to adhere to the temperature or al adherend of該被wear body The adhesion rate of the deposit is estimated, and the necessary addition amount of the high-temperature deposit inhibitor is calculated from the estimated value.

Hot deposit control method according to claim 5, selected from claims 1 to Oite in any one of 4, the hot deposit control agent is Mg compound, Si compound, Ca compound, Al compound, and Fe compounds and it is characterized in at least one Tanedea Rukoto.

In the present invention, an adherend such as a sampling tube is inserted into the furnace or the flue, and the adhesion state of the deposit in the furnace or the flue, that is, the amount of the deposit adhering to the adherend, the deposit get the calibration curve of the temperature of the body, on the basis of the calibration curve, to quickly follow the fluctuations in the furnace and the flue situation, it is possible to perform the addition control adhesion inhibitor.

It is a side view of a to-be-adhered body. It is an expanded sectional view of an adherend. It is an expanded sectional view of another adherend. It is sectional drawing which shows the example of attachment of a to-be-adhered body. It is a graph which shows the measurement result in an example of an experiment. It is a graph which shows the measurement result in an example of an experiment. It is a graph which shows the measurement result in an example of an experiment. It is a graph which shows the measurement result in an example of an experiment. It is a graph which shows the measurement result in an example of an experiment. It is a graph which shows the measurement result in an example of an experiment.

  Hereinafter, the present invention will be described in more detail.

  In this invention, a to-be-adhered body is inserted in the high temperature gas in a furnace or a flue, and the adhesion tendency of a deposit | attachment is determined based on the adhesion status of the deposit | attachment of this adherend.

  The adherend is preferably a tubular member made of a high-temperature corrosion-resistant metal material such as iron or titanium. In order to protect the adherend, it is preferable to cool the tubular adherend through a refrigerant such as air, steam or water. This refrigerant may be discharged into the furnace or flue, or may be circulated and cooled in the furnace or outside the flue for reuse. Alternatively, a thermocouple may be inserted into the tubular adherend, and the temperature may be measured to estimate the reduction in the heat recovery rate of the boiler water tube due to high-temperature deposits, the deposition rate, and the like. Further, the adherend may be prevented from becoming excessively hot, and deterioration due to the temperature of the adherend may be prevented.

  When measuring the temperature with a thermocouple, the temperature outside the tube may be measured by inserting the thermocouple deeply so that the tip of the thermocouple protrudes beyond the tip of the tubular adherend. The temperature inside the adherend may be measured by inserting the tip of the thermocouple into the tubular adherend. Further, the temperature at a plurality of points may be measured by moving the tip position of the thermocouple. In this way, it is possible to measure temperatures at a plurality of locations without using a plurality of thermocouples.

  Although it depends on the size of the combustion equipment, the adherend preferably has an effective length (length inserted in the furnace or flue) of about 200 to 3000 mm and an outer diameter of about 10 to 50 mm. The insertion direction may be any of a horizontal direction, a vertical direction, and an oblique direction. As the refrigerant, air, steam, or water is suitable. The flow rate of the refrigerant is preferably about 1 to 1000 L / min although it depends on the size of the combustion facility. The time for which the adherend is inserted into the furnace or flue is preferably about several minutes to several weeks, especially about 1 to 24 hours. The measurement frequency when the adherend is pulled out from the furnace or the flue to measure the amount of deposit and the thickness of the deposit is preferably about once every few days to several weeks.

  The method for measuring a high-temperature deposit according to the present invention is suitable for investigating the effect of suppressing adhesion when a deposit inhibitor is added to a high-temperature gas. To examine the effect of the deposit inhibitor, first insert the adherend into the high-temperature gas before adding the deposit inhibitor, and determine the deposit amount, deposit thickness, etc. for a predetermined time before adding the high-temperature deposit inhibitor. Measure and investigate the adhesion rate. Next, a predetermined amount of the high-temperature deposit inhibitor is added, and the deposition rate is measured under the same conditions. And the adhesion inhibitory effect is calculated | required by contrasting with the adhesion rate before high temperature deposit | attachment inhibitor addition.

  Before confirming the adhesion suppression effect, analyze the deposit collected in advance, such as in open inspection of the furnace or flue, or insert the adherend into the high-temperature gas before adding the deposit suppressant, and It is preferable to analyze the deposits attached to the adherend and select the type of high-temperature deposit inhibitor.

  The relationship between the concentration of dust in the high-temperature gas in the furnace or flue and the addition rate of the deposit inhibitor is used as a calibration curve, and the amount of scattered dust in the exhaust gas is measured to establish a standard for the addition rate. The addition amount of the kimono inhibitor may be determined (Experimental Example 1 described later).

  Alternatively, a high-temperature deposit inhibitor may be added suddenly, and the addition amount may be increased or decreased from the deposition rate at that time, and the addition amount adjusted while observing the deposition rate (Run 3 in Experimental Example 2 described later).

  Even if the adherend is not frequently inserted and removed, the adhesion amount may be estimated from the temperature inside the tubular adherend or the temperature difference between the outside and inside the tubular adherend, and the addition amount of the high-temperature deposit inhibitor may be increased or decreased. In that case, it is necessary to grasp the thermal conductivity of the deposit in advance. In addition, by preliminarily obtaining the relationship between the temperature in the tubular adherend or the temperature difference between the inside and outside of the tubular adherend and the amount of deposit as a calibration curve, the amount of deposit is predicted and the addition of a high-temperature deposit inhibitor The amount may be determined or controlled. When measuring the temperature inside the tubular adherend or the temperature difference outside the tubular adherend, it is preferable that the flow rate of the refrigerant passing through the tubular adherend is constant.

  Adjust the frequency of physical peeling action such as soot blow from the temperature inside the tubular adherend, the temperature difference inside and outside the adherend, the adhesion speed, and the appearance of the deposit measured by the adherend equipped with a temperature measuring element such as a thermocouple. Also good.

  As a high-temperature deposit inhibitor, one or two of Mg compound, Fe compound, Si compound, Ca compound, and Al compound (for example, carbonate, oxide, hydroxide, carboxylate) having a particle size of 1 to 10,000 nm are used. The powder composed of the above or a dispersion in which these are dispersed in a solvent such as water can be used.

  The high temperature deposit inhibitor may be added to the fuel or incinerated material burned in the furnace, and may be sprayed into the furnace atmosphere or flue gas. The addition amount is preferably 0.0002 to 20 wt% with respect to the fuel or incinerated product, or 0.01 to 200 wt% with respect to the amount of dust in the gas.

  When adding a powder deposit inhibitor, pump the chemical with a compressor or blower, or if using existing cooling air or auxiliary air lines, inject the line into the cooling air or auxiliary air piping. Can be transferred and added. Moreover, when adding a deposit | attachment inhibitor to a fuel, you may add to a fuel directly from a powder supply apparatus, or you may transfer to a fuel conveyance line with a conveyor.

  In the case of adding a liquid deposit inhibitor, it is preferable to install an addition nozzle at the addition site and spray the deposit inhibitor liquid. This nozzle is preferably one that can be added uniformly with a droplet diameter of about 2 to 3000 μm. Specifically, the nozzle preferably has a droplet diameter of 2 to 3000 μm, a spray flow rate of 100 to 1000 L / Hr, and a spray pressure of about 1.0 to 5.0 MPa. Further, as in the case of powder, a liquid deposit inhibitor may be added directly to the fuel.

  In the case of adding the powder deposit inhibitor to the furnace or flue, it is preferable to check the deposit spot of the deposit in the facility in advance and install a nozzle in the vicinity (especially immediately upstream). A dedicated nozzle installation port may be provided, and if there are substitutes such as a soot blow line and an inspection flange in advance, these may be used. It is preferable to install a nozzle before the start of operation of the furnace and start adding the high-temperature deposit inhibitor at a stage where the condition in the furnace is stabilized for a while after the start of operation.

  The deposit inhibitor is injected intermittently or continuously during operation of the facility. In the case of intermittent injection, it is desirable to control the drug supply device, electromagnetic valve, motor operated valve, etc. with a timer or flow rate. In the case of liquid addition, either stock solution injection or line injection may be used. The standard of the addition time of the drug is several minutes to several hours / time, and is set to intermittent injection once a day or a predetermined amount continuous injection.

By suppressing the addition of the adhering substance inhibitor based on the adhering state of the adhering substance to the adherend, it is possible to stably suppress the adhering of the high temperature adhering substance. This ensures the safety of workers by reducing cleaning work, reduces cleaning costs, prolongs the operating days by avoiding emergency stoppage, maintains the heat recovery rate by suppressing deposits on boiler water pipes, and fuel costs by efficient combustion It is possible to contribute to energy saving, such as reducing CO2 emissions and CO ₂ emissions.

  FIG. 1 is a side view showing a preferred example of the adherend.

  The adherend 1 is tubular and has a flange 1f at the rear end. The tip of the adherend 1 may be open or closed. When the thermocouple is projected from the tip into the furnace or the flue, the tip of the adherend 1 is assumed to be open. The adherend need only be a single circular tube as shown in FIG. 2, but may be a double tube having a concentric outer tube 1a and inner tube 1b as shown in FIG. In the case of FIG. 3, the tip of the outer tube 1a is closed, the tip of the inner tube 1b is opened, and the tip of the inner tube 1b is slightly retracted (separated) from the inner surface of the tip of the outer tube 1a. Keep it. In the case of an adherend consisting of a double pipe as described above, the refrigerant is forwarded between the outer pipe 1a and the inner pipe 1b, and the refrigerant is circulated in such a manner that the refrigerant is returned to the inner pipe 1b. be able to. When the refrigerant is passed through the single pipe of FIG. 2, the refrigerant is caused to flow out from the tip of the adherend 1 into the furnace or the flue.

  FIG. 4 is a cross-sectional view showing a structural example for attaching the adherend 1 to the furnace body or the flue 2.

  The furnace body or flue 2 has a refractory 3 and an iron skin 4 covering the outer surface of the refractory 3. A hole 5 is provided through the furnace body or flue 2. A short tubular mounting seat 6 is projected outwardly from the iron skin 4 coaxially with the hole 5. A flange 6f is provided at the front end of the mounting seat 6 in the protruding direction. The adherend 1 is disposed so as to protrude from the mounting seat 6 through the hole 5 and into the furnace or the flue, and the flange 1f is overlapped with the flange 6f and fixed by a bolt (not shown) or an appropriate clip. To do. A thermocouple is inserted into the adherend 1 or a refrigerant is circulated.

  Hereinafter, examples and comparative examples will be described.

  In the following examples and comparative examples, the present invention was applied to a kiln talker furnace for incineration of combustible materials having an incineration capacity of 100 t / day. The exhaust gas from the incinerator is collected by a bag filter through a waste heat boiler and a gas cooling facility. Deposits easily adhere to the waste heat boiler water pipe (exhaust gas temperature 800 to 900 ° C.). The injection point of the deposit control agent was the flue at the entrance of the waste heat boiler.

  As the adherend, a sampling tube made of a stainless steel single tube having a total length of 1500 mm (a length protruding into the flue of 800 mm), an outer diameter of 17.3 mm, and an inner diameter of 10.7 mm was used.

  As a cooling medium, air was flowed at 30 L / hr, and this air was discharged into the furnace.

  The insertion time of the adherend was 4 h.

After 4 hours, the adherend was gently removed, allowed to cool to room temperature, and the weight of the deposit was measured. After this measurement, the deposit was peeled off and a new adherend of the same type was placed in the furnace again. Based on this amount of deposits, the amount of MgCO ₃ powder added as an deposit inhibitor was adjusted.

<Experimental Example 1: Determination of formula for calculating drug addition rate>
The required addition rate of the agent per dust deposition rate on the adherend was calculated from the dust deposition rate on the adherend in the preliminary test, the result of the desktop test of the water tube deposit measured in advance, and the amount of dust collected from the boiler outlet.

  In addition, it is necessary to collect the dust at the boiler inlet, but in consideration of the sampling accuracy, in this embodiment, it is assumed that the scattered dust at the boiler outlet is almost the same as the scattered dust at the boiler inlet. Was substituted.

  It was 100 kg / h when collecting dust in the exhaust gas from the boiler according to JIS Z 8808. Moreover, the adhesion rate of the deposits on the adherend was 65 g / 4 h.

  The following test was performed in order to determine the amount of deposit added necessary to suppress the deposit.

The dust adhering to the water pipe is crushed and a predetermined amount of MgCO ₃ is mixed and put in a crucible. Place the crucible in an electric furnace and heat at 900 ° C. for 90 minutes. The heated sample is allowed to cool naturally, and the compressive strength is measured with a soil hardness meter. The addition rate of MgCO _{3 at which} the compressive strength reached 0.0 kg / cm ² was defined as the required addition rate.

The test results are shown in FIG. As shown in FIG. 5, the required amount of MgCO ₃ added in this case was 15% with respect to the dust weight.

  From the above test, the required addition amount of the deposit inhibitor added to the furnace (hereinafter sometimes referred to as a drug) was calculated as follows.

Necessary amount of chemicals added = amount of dust at boiler outlet x MgCO ₃ required rate of addition x {(Sampling tube deposition rate) / (Adhesion rate of deposit on adherend in preliminary test)}
= 100 (kg / h) x 15% x (Sampling tube attachment speed)
/ 65 (g / 4h)

<Experimental example 2 Example and comparative example in which adherends are installed on the downstream side of the drug injection point>
The chemical injection point was the flue at the entrance of the waste heat boiler. The adherend was installed at a location 2500 mm downstream of the exhaust gas from this chemical injection point. The adherend was the sampling tube described above, and the air flow rate was also as described above.

  The test was performed under the following conditions of Runs 1 to 3.

  Run1 No chemical addition (blank): After the start of operation of the furnace, on the 2nd, 10th and 20th days, only the deposition rate was measured in 4 hours by the adherend to which the adhered matter did not adhere. No drug was added.

  Run2 No drug injection amount control (fixed amount injection): The adhesion rate was measured by the adherend every 4 hours on the 2nd, 10th and 20th days after the start of operation of the furnace. The drug injection amount was a constant value of 15 kg / h.

  Run3 With drug injection amount control: After the start of operation of the furnace, the adhesion rate is measured by the adherend on the 2nd, 10th and 20th days, and the drug injection amount is adjusted until the adhesion rate reaches about 20g / 4h. The deposition rate was measured. For Run 3, the drug injection amount was constant after the deposition rate reached about 20 g / 4 h.

Table 1 shows the measurement results of the deposition rate (g / 4h) of the deposits on the adherend and the amount of the drug added (kg-MgCO ₃ / h).

  As shown in Table 1, in Run 3, the adhesion rate measured on the second day after the start of operation of the furnace was 32 g / 4 h. The drug injection amount was adjusted from 15 kg / h to 18 kg / h in order to approach the target value of 20 g / 4 h, and the adhesion rate was measured again to be 18 g / 4 h. Therefore, it was determined that the target value was reached, and the operation was continued at the injection amount determined on the second day from the second day to the ninth day. The same operation was performed on the 10th and 20th days. The drug injection amount on the 10th to 19th days is a value adjusted on the 10th day, and the drug injection amount on the 20th to 30th days is a value adjusted on the 20th day.

  To determine the effect, the amount of waste heat boiler steam generated after one month was compared. The results are shown in FIG.

  From the comparison of Run 1 and Run 2 in Table 1 and FIG. 6, the deposition rate on the adherend is correlated with the amount of steam generated, that is, the deposition rate of the high-temperature deposit on the boiler water pipe. It was found that it was possible to grasp the state of adhesion to the boiler water pipe by detection.

  In Run 3, finding a proper injection amount of the drug did not cause a large decrease in the amount of generated steam even after one month.

  Comparing Run2 and Run3, it can be seen that the deposition rate is stably reduced to 20 g / 4h by controlling the injection amount of the drug according to the deposition status of the deposit. In Run 3, the amount of steam generated after one month passed was also higher than that in Run 2.

<Experimental example 3 Example and comparative example in which adherends are installed on the upstream side and downstream side of the drug injection point>
An adherend a similar to the above was installed at a location 2500 mm upstream of the exhaust gas from the chemical injection point, and an adherend b similar to the above was installed at a location 2500 mm downstream of the exhaust gas from the chemical injection point.

  The test was performed under the following conditions of Run 4-6.

  No addition of Run 4 (blank): After the start of the operation of the furnace, only the deposition rate on the adherend was measured every 4 hours on 2, 10, and 20 days. No drug was added.

  Run 5 No drug injection amount control (fixed amount injection): The adhesion rate to the adherend was measured for 4 hours on the 2nd, 10th and 20th days after the start of operation of the furnace. After the operation of the furnace was started, the drug injection amount was determined based on the adhesion rate on the second day. Thereafter, the amount of drug injected was set to this value.

  Run 6 With drug injection amount control: After the start of operation of the furnace, the adhesion rate was measured by the adherend a for 4 hours on the 2nd, 10th, and 20th days, and the drug injection amount was controlled. For Run 6, the drug injection amount was changed immediately after measuring the adhesion rate. During the 2nd to 9th days, the operation was continued at the drug injection amount determined on the 2nd day. The same operation was performed on the 10th and 20th days. The drug injection amount on the 10th to 19th days is the value on the 10th day, and the drug injection amount on the 20th to 30th days is the value on the 20th day.

Table 2 shows the deposition rate (g / 4h) of the deposit on the adherend a and the amount of the drug added (kg-MgCO ₃ / h).

  About Run 4-6, the waste heat boiler steam generation amount after one month was compared. The results are shown in FIG. In addition, Table 3 shows a result of comparing the adhesion rate to the adherend b.

  As shown in Table 3, the adhesion rate to the adherend b hardly changed in the blank (Run 4), but the adhesion rate decreased in Run 5 with no drug injection amount control. As a result, the steam generation amount was maintained.

  As in Run 6, by controlling the drug injection amount according to the adhesion situation, the adhesion rate to the adherend is maintained at around 20 g / 4 h, and the steam generation amount is also maintained at about 7-8 ton / day. became.

<Experimental Example 4 Preparation of calibration curve for temperature and amount of deposit in adherend>
Experimental Example 4 is a method for estimating the amount of adhesion to the adherend from the temperature change in the adherend tube in advance when the insertion port of the adherend is small, and calculating the amount of drug addition from this estimated value.

  In the following, a method of inserting an adherend from a drug addition port in advance, measuring the temperature in the tube of the adherend, and creating a calibration curve between the temperature in the tube of the adherend and the amount of deposits was shown.

  However, when the fluctuation of the exhaust gas inlet temperature is large, it is desirable to employ a method of directly measuring the amount of adhesion or a method of creating a calibration curve between the temperature difference between the inside and outside of the adherend pipe and the amount of deposit.

  As the adherend, the same sampling tube as described above was used, and air was circulated as a cooling medium at 30 L / min. The insertion time of the adherend was set to 1, 4 or 8 hours. A thermocouple was installed in the adherend tube. The insertion length of the thermocouple was 1450 mm when measuring the temperature inside the adherend tube.

  Insert the adherend so that the effective length in the flue is 800 mm, measure the temperature in the tube of the adherend when a predetermined time has passed while circulating air, gently extract the adherend, and let it cool to room temperature did. Then, the weight of the deposit | attachment adhering to a to-be-adhered body is measured.

  FIG. 8 shows the relationship between the temperature inside the adherend and the amount of adhesion.

In addition, the in-pipe temperature of the adherend and the amount of deposits at 1 h, 4 h, and 8 h are as follows.
1h: In-pipe temperature of 771 ° C., amount of deposit 15.5 g
4h: tube temperature 758 ° C., amount of deposits 64.4 g
8h: tube temperature 744 ° C, amount of deposit 470g

<Experimental Example 5> Examples and Comparative Examples of Drug Injection Amount Control Based on the Tube Temperature of an Adherent Installed Downstream from the Drug Injection Location>
In Experimental Example 4, the adherend was installed 2500 mm downstream from the drug injection point, and the same drug as that described above was injected.

  The test was performed according to the following conditions of Run 7-9.

  Run 7 additive-free (blank): After the start of operation of the furnace, only the temperature inside the tube after 4 hours from the time when the adherend was inserted into the flue on the second, tenth and twentyth days was measured. No drug was added.

  Run 8 No drug injection amount control (fixed amount injection): After the start of operation of the furnace, the temperature inside the tube was measured after 4 hours had passed since the adherend was inserted into the flue on the second, tenth and twenty days. The drug injection amount was set to a constant value of 15 kg / h, and the drug injection amount control was not changed.

  Run9 With chemical injection amount control: After the start of operation of the furnace, the temperature inside the tube after 4 hours has passed since the adherend was inserted into the flue on the 2nd, 10th and 20th days. The amount of drug injection was adjusted so as to be in the vicinity of 20 g / 4 h).

Table 4 shows the tube temperature (° C.) of the adherend and the amount of drug added (kg-MgCO ₃ / h).

  On the second day after the start of the operation of the furnace, the temperature in the tube 2 hours after inserting the adherend was measured and found to be 765 ° C. In order to approach the target value of 770 ° C., the drug injection amount was adjusted from 15 kg / h to 17 kg / h, and the in-tube temperature of the adherend was measured again to be 770 ° C. It was judged that the target value was reached, and the drug injection was continued at the same drug injection amount. The same operation was performed on the 10th and 20th days after the start of operation of the furnace.

  In order to determine the effect, the amount of waste heat boiler steam generated after one month was compared. The results are shown in FIG.

  From FIG. 9, it was confirmed that the amount of drug injection can be accurately controlled even when the adherend is installed downstream of the drug injection site and the temperature in the tube is measured.

  In addition, it is presumed that the amount of adhering material is large because the temperature in the tube of the adherend is lower in Run 7 with no drug added.

<Experimental example 6> Examples and comparative examples of drug injection amount control based on the in-pipe temperatures of the adherends installed on the upstream side and downstream side of the drug injection point, respectively>
In Experimental Example 5, adherends were similarly installed at a location 2500 mm upstream from the drug injection location, and air was circulated through each adherend as a cooling medium at 30 L / min. The sampling tube insertion time was 4 hours. A thermocouple was installed in the tube of each adherend. The insertion length was 1450 mm.

  The test was performed under the following conditions of Run 10-12.

  Run 10 No addition (blank): Measure only the tube temperature to each adherend on the 2nd, 10th and 20th days after the start of operation of the furnace. No drug was added.

  Run 11 No drug injection amount control (fixed amount injection): The adhesion rate to each adherend was measured on the 2nd, 10th and 20th days after the start of operation of the furnace. After the operation of the furnace was started, the drug injection amount was determined based on the temperature in the tube of the adherend on the upstream side on the second day. Thereafter, the amount of drug injected was set to this value.

  Run12 With chemical injection amount control: After starting operation of the furnace, the tube temperature is measured on the 2nd, 10th, and 20th days, the adhesion rate is estimated from the tube temperature of the upstream adherend, and the drug is added from the estimated value. The amount was calculated and immediately changed to the amount added.

Table 5 shows the in-tube temperature (° C.) and the chemical addition amount (kg-MgCO ₃ / h) of the adherend on the upstream side. Table 5 shows the estimated attachment speed of the attached matter.

効果を判定するために、１ヵ月後の廃熱ボイラ蒸気発生量を比較した。結果を第１０図に示す。

In order to determine the effect, the amount of waste heat boiler steam generated after one month was compared. The results are shown in FIG.

  Table 6 shows the tube temperature (° C.) of the downstream adherend after the drug injection.

  In Run 10, since no chemical was added, the tube temperature of the upstream adherend and the tube temperature of the downstream adherend were almost the same.

  In Run 11, the tube temperature of the downstream adherend was slightly higher than the tube temperature of the upstream adherend. It is estimated that the heat recovery rate of the downstream adherend was improved by the effect of the drug.

  As for Run 12, the temperature of the downstream adherend is clearly higher than the temperature of the upstream adherend, reducing the amount of adhesion to the downstream adherend and improving the heat recovery rate. It is estimated that In addition, by controlling the injection amount of the drug, the steam generation amount was maintained at about 8 ton / day.

DESCRIPTION OF SYMBOLS 1 Adherent 1f Flange 2 Furnace or flue 3 Refractory 4 Iron skin 5 Hole 6 Mounting seat 6f Flange

Claims (5)

Inserting a tubular adherend to attach a substance in the gas into the hot gas in the furnace or flue,
A high-temperature deposit suppression method for controlling the addition amount of a high-temperature deposit inhibitor added to a high-temperature gas based on the adhesion amount of the deposit adhered to the adherend and the temperature of the adherend,
Gets the adhesion amount of deposits adhered to the adherend, a calibration curve of the temperature of the該被deposition body,
A method for suppressing high-temperature deposits, which comprises controlling the amount of the high-temperature deposit inhibitor to be added according to the calibration curve. The acquisition of the calibration curve according to claim 1, wherein the adherend is inserted into the hot gas in the furnace or flue at different insertion times a plurality of times, and a predetermined insertion time has passed each time. the temperature of the該被deposition body was measured at, then pull out the該被adherend from the furnace in or flue to measure the deposition amount of deposits adhered to the adherend, from these measurement results A method for suppressing high-temperature deposits, comprising producing the calibration curve. In claim 1 or 2, the furnace or flue is provided with a chemical injection point for adding a high temperature deposit inhibitor into the high temperature gas in the furnace or flue,
Arranging the adherend downstream of the chemical injection point of the furnace or flue,
Wherein on the basis of a calibration curve, the high temperature deposit control method characterized in that temperature of the該被adhesive body to control the addition amount of the high temperature deposit control agent to a predetermined temperature. In claim 1 or 2, the furnace or flue is provided with a chemical injection point for adding a high temperature deposit inhibitor into the high temperature gas in the furnace or flue,
Placing the adherend upstream of the drug injection point in the furnace or flue,
Based on the calibration curve, that estimates the deposition rate of deposits adhering to the temperature or al adherend of該被wear body, to calculate the required amount of the hot deposit control agent from the estimated value A feature of suppressing high-temperature deposits.   5. The high-temperature deposit according to claim 1, wherein the high-temperature deposit inhibitor is at least one selected from Mg compounds, Si compounds, Ca compounds, Al compounds, and Fe compounds. Suppression method.

Images