Method for removing deposit inside pipe for conveying adhesive granular material, method for conveying adhesive granular material, and cement clinker production method

Abstract

To remove deposit while suppressing heat energy reduction when conveying an adhesive granular material including meat and bone meal or the like in cement production equipment or the like.SOLUTION: An adhesive granular material including meat and bone meal is conveyed into a pipe for conveying adhesive granular material, and in the middle of the conveyance, conveyance is switched to conveyance of adhesive granular material to convey dried sewage sludge for a predetermined period of time and remove the deposit in the pipe, and then, the adhesive granular material is conveyed again. Switching between the adhesive granular material and dried sewage sludge may be performed while detecting a pressure fluctuation inside the pipe for conveying adhesive granular material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for removing deposits from inside a pipe when transporting adhesive powdery or granular material such as meat and bone meal. [Background technology]

[0002] In the cement manufacturing process, pulverized coal, made by drying and crushing coal, has been the primary thermal energy source. In recent years, the use of waste plastics, waste oil, and meat and bone meal as thermal energy sources has contributed to a recycling-oriented society. Furthermore, cement manufacturing facilities frequently use equipment that pneumatically transports powdered materials through pipes, including the transport of meat and bone meal. When using this meat and bone meal, the oil contained in it makes it highly adhesive, which can lead to adhesion to the inner surface of the pipes and cause blockages. When blockages occur, the heat energy source from the meat and bone meal becomes insufficient, resulting in increased use of pulverized coal. Therefore, measures are needed to prevent pipe blockages due to the adhesion of meat and bone meal.

[0003] Therefore, Patent Document 1 discloses a cleaning method for removing deposits from inside a pipe with a small inner diameter using a sandblaster that can move along the inner wall of the pipe. In this case, it is necessary to stop the pumping of powder and granular material through the target pipe during cleaning.

[0004] Meanwhile, Patent Document 2 discloses a method for conveying meat and bone meal in a cement manufacturing facility by mixing fly ash with meat and bone meal to reduce adhesion, and then pneumatically conveying the mixed powder and granules. In this case, because fly ash has a low calorific value, the calorific value decreases depending on the amount of fly ash mixed. Furthermore, there is a concern that non-combustible components in the fly ash, which have a different chemical composition from cement, may fall onto the semi-molten clinker, changing the mineral composition of the clinker and adversely affecting the quality of the final cement product. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 187381 / 1981 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-91085 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, when transporting oily meat and bone meal, the oil would adhere to the inside of the pipes, causing blockages, increasing the amount of pulverized coal used.Furthermore, the supply of powdered material had to be stopped in order to remove the meat and bone meal that had adhered to the inside of the pipes, which also increased the amount of pulverized coal used.

[0007] The present invention has been made in view of the above circumstances, and aims to remove adhesions while suppressing a loss of thermal energy when transporting adhesive powders and granular materials, including meat and bone meal, in cement manufacturing facilities, etc. [Means for solving the problem]

[0008] The method for removing deposits from inside a pipeline for transporting adhesive powder or granular material of the present invention transports dried sewage sludge into the pipeline for transporting adhesive powder or granular material, thereby removing deposits from inside the pipeline.

[0009] Dried sewage sludge is sewage sludge generated in sewage treatment facilities and the like that has been dried with hot air to enable it to be used as a resource such as fertilizer. Because it is dried sludge, it is hard and easily absorbs oil, allowing it to absorb oil deposits inside pipes while removing the deposits from the pipe's inner surface. In addition, because it has a higher loss on ignition than fly ash and a larger calorific value, even when adhesive powder or granular material is used as the thermal energy source, the loss of thermal energy due to transportation of the dried sewage sludge can be suppressed.

[0010] In the method of removing deposits from inside a pipe for transporting adhesive powder or granular material according to the present invention, the adhesive powder or granular material may include meat and bone meal. When the adhesive powder or granule contains meat and bone meal, the removal effect of dried sewage sludge is remarkable. In addition, the dried sewage sludge has a loss on ignition close to that of meat and bone meal and a calorific value equivalent to that of meat and bone meal, so that the loss of thermal energy can be suppressed.

[0011] The method for transporting adhesive powder or granular material of the present invention involves transporting adhesive powder or granular material through a pipe, and during the transport, switching to transporting the adhesive powder or granular material and transporting dried sewage sludge for a predetermined period of time to remove adhesions within the pipe.

[0012] By switching to transport of dried sewage sludge during the transport of adhesive powders, it is possible to remove the deposits on the inner surface of the pipe and smoothly resume and continue transport of the adhesive powders. In addition, even if the adhesive powders are a thermal energy source, the loss of thermal energy during the switch to dried sewage sludge is also suppressed.

[0013] In the method for transporting adhesive powder or granular material of the present invention, the pressure in the pipe through which the adhesive powder or granular material is transported is measured, and when adhesions in the pipe are detected from the pressure measurement results, the transport is switched to the transport of the dried sewage sludge material.

[0014] By measuring the pressure inside the pipe, it is possible to grasp the state of blockage inside the pipe. When adhesions inside the pipe are detected from the results of this pressure measurement, the adhesions on the pipe can be removed by switching the transport from adhesive powder to dried sewage sludge. By switching the transport based on the results of pressure measurement, it becomes possible to automate the transport of adhesive powder.

[0015] The method for producing cement clinker of the present invention is carried out in a cement production facility in which meat-and-bone meal is used as at least a part of a thermal energy source, by transporting dried sewage sludge instead of the meat-and-bone meal into a pipe for transporting the meat-and-bone meal for a predetermined period of time.

[0016] By transporting the dried sewage sludge, clogging of pipes caused by transporting meat and bone meal can be eliminated, and the dried sewage sludge has a large calorific value, so cement clinker can be produced stably. Furthermore, since clogging of the piping due to meat and bone meal can be prevented, meat and bone meal can be supplied stably, and the amount of pulverized coal used can be reduced.

[0017] In the method for producing cement clinker of the present invention, the ignition loss of the meat and bone meal can be 70% by mass or more and 85% by mass or less, and the calorific value can be 4000 kcal / kg or more and 5500 kcal / kg or less. The ignition loss of the dried sewage sludge product can be 65% by mass or more and 80% by mass or less, and the calorific value can be 3500 kcal / kg or more and 5000 kcal / kg or less.

[0018] Since the ignition loss and calorific value of dried sewage sludge are similar to those of meat and bone meal, even when the transportation in the pipes is switched to dried sewage sludge, there is little loss in thermal energy, and the amount of heat required to produce cement clinker can be secured, making it possible to produce high-quality cement clinker. [Effects of the Invention]

[0019] According to the present invention, by flowing dried sewage sludge into the pipe, the oil adhering to the inside of the pipe can be absorbed and removed from the inner surface of the pipe, and the transportation of the adhesive powder or granular material can be smoothly resumed and continued. Moreover, since the dried sewage sludge has a higher loss on ignition than fly ash and a large calorific value, even when the adhesive powder or granular material is used as a thermal energy source, the loss of thermal energy can be suppressed. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing a cement manufacturing facility according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a supply system for combustible waste in the cement manufacturing facility of FIG. 1. [Figure 3]FIG. 10 is a schematic diagram similar to FIG. 2, showing another example of a supply system for combustible waste. [Figure 4] 10 is a graph showing an example of fluctuations in pressure over time in a waste supply pipe. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] Fig. 1 shows an example of a cement manufacturing facility. This cement manufacturing facility 1 includes a raw material storage facility 2 for individually storing cement raw materials such as limestone, clay, silica stone, and iron raw materials, a raw material mill and dryer 3 for crushing and drying these cement raw materials, a preheater 4 for preheating the powdered cement raw materials obtained in the raw material mill, a cement kiln 5 for firing the cement raw materials preheated by the preheater 4, and a clinker cooler 6 for cooling the cement clinker after being fired in the cement kiln 5.

[0023] The cement kiln 5 is a cylindrical rotary kiln that is oriented horizontally and slightly inclined downward from the kiln end 7 to the kiln front 8. By rotating around its axis, cement raw materials supplied to the kiln end 7 from the preheater 4 are sent to the kiln front 8, and during this process, the raw materials are heated and fired to about 1450°C by burners 9 in the kiln front 8 to produce cement clinker, which is then sent from the kiln front 8 to the cooler 6. After being cooled to a predetermined temperature in the cooler 6, the cement clinker is sent to the finishing process.

[0024] Burner 9 serves as the main thermal energy source, injecting coal (pulverized coal) into cement kiln 5 together with air to combust, and nozzle 10 is provided near burner 9 for supplying combustible waste (adhesive powder and granular material of the present invention; particularly meat and bone meal) such as waste plastics, waste tires, and meat and bone meal. A main energy source supply system 11 connected to burner 9 supplies pulverized coal, obtained by pulverizing coal in a coal silo 12 using a mill 13, to burner 9 together with air using a blower (not shown). Meanwhile, waste supply piping (adhesive powder and granular material transport piping of the present invention) 14 connected to nozzle 10 transports waste stored in tank 15 together with air using a blower (not shown), and blows it out of nozzle 10 for combustion.

[0025] On the other hand, exhaust gas generated in the cement kiln 5 passes through the preheater 4 from bottom to top and is then introduced into the raw material mill and dryer 3, which simultaneously crushes and dries the cement raw materials by receiving the exhaust gas from the cement kiln 5. The exhaust gas from the raw material mill and dryer 3 is released into the atmosphere via a dust collector 16.

[0026] The arrangement of the burner 9 and nozzle 10 provided in the kiln front section 8 of the cement kiln 5 is not limited to the example shown in Figure 1, and the nozzle 10 may be inserted into the center of the burner 9, for example.

[0027] When cement clinker is produced using the cement manufacturing facility 1 configured as above, cement raw materials from the raw material storage 2 are pulverized and dried in the raw material mill and dryer 3, sent to the preheater 4 and preheated before being supplied to the cement kiln 5 where they are burned, cooled in the clinker cooler 6, and then subjected to a finishing process to produce cement clinker. At this time, pulverized coal is supplied to the cement kiln 5 from the burner 9, and combustible waste is supplied from the nozzle 10 and used as a heat source.

[0028] In the production of cement clinker, when meat and bone meal is used as the combustible waste to be blown into the cement kiln 5 from the nozzle 10, as mentioned above, the meat and bone meal is highly sticky, so some of it will adhere to the inner surface of the waste supply pipe 14. As the meat and bone meal is used for a long time, the adhesions will gradually increase in size, which may clog the flow path in the pipe 14. Therefore, after the meat and bone meal has been transported continuously for a predetermined time, dried sewage sludge is supplied into the waste supply pipe 14 instead of the meat and bone meal.

[0029] This dried sewage sludge is sewage sludge generated in sewage treatment facilities and the like that has been dried with hot air to enable it to be used as a resource such as fertilizer, and since it is dried sludge, it is hard and easily absorbs oil, so it can absorb oil from deposits inside the waste supply pipe 14 while peeling off the deposits from the inner surface of the pipe 14. Finely granulated sludge with a particle size of 5 mm or less is used.

[0030] In addition, the ignition loss and calorific value of dried sewage sludge are greater than those of fly ash and are similar to those of meat and bone meal, so the loss of thermal energy can be suppressed even after switching from meat and bone meal for transportation. Furthermore, as will be described later, the impurities contained in dried sewage sludge, such as chlorine (Cl) and phosphorus (P), are similar to those in meat and bone meal, so there is little loss in the quality of cement clinker.

[0031] After transporting this dried sewage sludge for a predetermined time, most of the deposits in the waste supply pipe 14 have been removed, so the supply of the dried sewage sludge can be stopped and the transport of meat and bone meal can be switched back to the original method, allowing cement clinker to be continuously produced. It is preferable that the meat and bone meal contains bones about 1 cm long, as this allows some of the attached material to be removed during transport.

[0032] When transporting the meat-and-bone meal and the dried sewage sludge alternately, the meat-and-bone meal and the dried sewage sludge are alternately charged into the tank 15 and piled up in layers, and then the lower layers are transported in order to the pipe 14, whereby the meat-and-bone meal and the dried sewage sludge can be transported alternately.

[0033] 2 shows that meat and bone meal A and dried sewage sludge B are alternately layered and piled up in tank 15, and are successively fed from the bottom up into waste supply pipe 14, and when one layer (meat and bone meal A) is gone, the next layer (dried sewage sludge B) is fed out. In this case, the timing for switching should be determined in advance depending on the stickiness of the meat and bone meal, and the amounts of meat and bone meal A and dried sewage sludge B should be set and piled up in tank 15 so that the switching can be done at that timing.

[0034] In addition to the case where meat and bone meal and dried sewage sludge are alternately stacked in one tank 15, dedicated tanks for meat and bone meal and dried sewage sludge may be installed and connected to pipes separately, so that the tanks can be switched between and supplied to the pipes. Figure 3 shows an example in which a tank 15A for meat and bone meal and a tank 15B for dried sewage sludge are provided separately, and valves 17A and 17B are provided in each tank 15A, 15B, so that either meat and bone meal or dried sewage sludge can be supplied from the two tanks 15A, 15B to the waste supply pipe 14.

[0035] In this case, the degree of clogging of the waste supply pipe 14 may be predicted based on the passage of time, etc., and the transport may be switched from meat and bone meal to dried sewage sludge, but it is also possible to switch while detecting the degree of clogging of the waste supply pipe 14. For example, a pressure gauge 18 may be provided midway along the waste supply pipe 14, and measurement data from this pressure gauge 18 may be analyzed by a computer (control unit) 19 to control the opening and closing of the valves 17A, 17B of both tanks 15A, 15B.

[0036] Specifically, when the computer 19 determines that the pressure in the waste supply pipe 14 measured by the pressure gauge 18 exceeds a predetermined value while the meat and bone meal is being transported, the computer 19 closes the valve 17A of the meat and bone meal tank 15A to stop the supply of meat and bone meal, and opens the valve 17B of the dried sewage sludge tank 15B to supply the dried sewage sludge to the waste supply pipe 14. Then, when the transport of the dried sewage sludge removes any deposits in the waste supply pipe 14 and the pressure in the pipe 14 measured by the pressure gauge 18 drops to a normal level, the supply of the dried sewage sludge is stopped and the supply of the meat and bone meal is resumed.

[0037] However, depending on the relative position of the pressure gauge 18 and the location of the clog in the pipe 14, a pressure increase or decrease may be detected when a clog due to deposits occurs in the pipe 14. If the pressure gauge 18 is located upstream of the location of the clog, the pressure will increase when the pipe 14 becomes clogged, and if the pressure gauge 18 is located downstream of the location of the clog, the pressure will decrease when the pipe 14 becomes clogged. For this reason, it is advisable to locate the pressure gauge 18 near the most upstream or most downstream position of the waste supply pipe 14.

[0038] In any case, if the pressure fluctuation (increase or decrease) exceeds a predetermined value compared to the normal state when there is no blockage or other abnormality in the waste supply pipe 14, it is possible to predict the occurrence of blockage in the pipe 14 and switch the transport from meat and bone meal to dried sewage sludge.

[0039] In either of the above methods, by alternately transporting meat-and-bone meal and dried sewage sludge, it is possible to remove deposits from the waste supply pipe 14 and transport the meat-and-bone meal smoothly. Moreover, dried sewage sludge has a higher loss on ignition and a larger calorific value than fly ash, etc., so it is possible to suppress the loss of thermal energy, and by providing a stable source of thermal energy, it is possible to produce cement clinker of stable quality. Furthermore, since clogging of the pipe 14 by meat and bone meal can be prevented, meat and bone meal can be supplied stably, and the amount of pulverized coal used can be reduced accordingly.

[0040] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In the embodiment, a case where meat and bone meal is used as a thermal energy source in a cement manufacturing facility is shown, but the present invention can also be applied when transporting adhesive powders and granules other than meat and bone meal and removing deposits from pipes for transporting such adhesive powders and granules. [Example]

[0041] Tests were conducted to demonstrate the effectiveness of the present invention. Using meat and bone meal and dried sewage sludge with a particle size of 5 mm, their ignition loss, chlorine (Cl) and phosphorus (P) contents were measured in accordance with the provisions of JIS R 5202. In addition, their calorific values ​​were measured in accordance with the provisions of JIS K 2279. The results are shown in Table 1.

[0042] [Table 1]

[0043] As is clear from Table 1, the ignition loss and calorific value of dried sewage sludge are similar to those of meat and bone meal. The chlorine and phosphorus contents are also similar, demonstrating that dried sewage sludge can be used as a substitute for meat and bone meal. Incidentally, according to the aforementioned Patent Document 2, fly ash has a calorific value of 2000 cal / g, whereas dried sewage sludge has a higher calorific value, and it is clear that there is little loss in thermal energy even when the transportation method is switched from meat and bone meal.

[0044] Next, using the device shown in FIG. 3, the pressure in the waste supply pipe 14 to the cement kiln was measured while meat and bone meal and dried sewage sludge were alternately transported into the pipe 14. Figure 4 shows the change in pressure inside the pipe over time during transportation. A shows the state when meat and bone meal is being transported, and B shows the state when dried sewage sludge is being transported. First, when meat and bone meal was first transported at 1.0 t / hour, the pressure in the pipe remained fairly stable for several hours after the start of transport, but then the pressure in pipe 14 gradually increased over time. It is assumed that deposits had accumulated in pipe 14. At first, the pressure increased relatively slowly, but the increase became sudden. Assuming that the deposits in pipe 14 had increased and caused a blockage, the transport of meat and bone meal was stopped and switched to dried sewage sludge, and the pressure in pipe 14 dropped relatively quickly. It is believed that this drop in pressure was due to the removal of deposits in pipe 14. When the pressure in pipe 14 had dropped to the specified value, the original meat and bone meal was transported instead of the dried sewage sludge.

[0045] As is clear from Figure 4, if adhesions occur inside the pipe 14 during transport of meat and bone meal and the pressure inside the pipe 14 fluctuates, the adhesions can be removed and the transport of the meat and bone meal can be resumed and continued by supplying dried sewage sludge into the pipe 14 instead of the meat and bone meal. Therefore, it can be seen that the transportation method of this embodiment is effective when transporting adhesive powdery or granular materials such as meat and bone meal, and that the adhesions can be removed by detecting pressure fluctuations inside the pipe 14 and switching the transport to dried sewage sludge.

[0046] In this case, a threshold value for pressure change can be set to detect sudden fluctuations in pressure as shown in Figure 4, or a threshold value for the absolute value of pressure can be set, and when either of these thresholds is exceeded, it can be determined that it is time to remove the deposits inside the pipe 14 and the transportation can be switched. [Explanation of symbols]

[0047] 1. Cement manufacturing facilities 2 Raw material storage facility 3 Raw material mill and dryer 4 Preheater 5. Cement kiln 6. Clinker Cooler 9 Burner 10 nozzles 11 Main energy supply system 14 Waste supply piping (piping for transporting adhesive powder and granular materials) 15 Tank 15A Meat and bone meal tank 15B Sewage sludge drying tank 17A, 17B valves 18 Pressure gauge 19 Computer (control unit)

Claims

1. A method for removing deposits from inside a pipe for transporting adhesive powder or granular material, comprising transporting dried sewage sludge into the pipe for transporting adhesive powder or granular material and removing the deposits from inside the pipe.

2. 2. The method for removing deposits from a pipe for transporting adhesive powder according to claim 1, wherein the adhesive powder contains meat and bone meal.

3. A method for transporting adhesive powders and granular materials, characterized by transporting adhesive powders and granular materials through a pipe, and during the transport, switching to transporting dried sewage sludge for a predetermined period of time to remove adhesions within the pipe.

4. A method for transporting adhesive powder or granular material according to claim 3, characterized in that the pressure of the pipe through which the adhesive powder or granular material is transported is measured, and when adhesions in the pipe are detected from the pressure measurement results, the method switches to transporting the dried sewage sludge material.

5. A method for producing cement clinker in a cement production facility in which meat and bone meal is used as at least part of a thermal energy source, characterized in that dried sewage sludge is transported for a predetermined period of time into a pipe for transporting the meat and bone meal instead of the meat and bone meal.

6. 6. The method for producing cement clinker according to claim 5, wherein the ignition loss of the meat and bone meal is 70% by mass or more and 85% by mass or less, and the calorific value is 4000 kcal / kg or more and 5500 kcal / kg or less.

7. 7. The method for producing cement clinker according to claim 5, wherein the ignition loss of the dried sewage sludge material is 65% by mass or more and 80% by mass or less, and the calorific value is 3500 kcal / kg or more and 5000 kcal / kg or less.

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