Cement clinker manufacturing equipment

Abstract

To provide a cement clinker production facility capable of efficiently removing mercury.SOLUTION: A cement clinker production facility 1 comprises a raw material preparation unit 2, a calcination unit 3, and a mercury removal unit 4. The mercury removal unit 4 comprises: a dust collection unit 41 that collects and recovers dust in exhaust gas discharged from the raw material preparation unit 2 or the calcination unit 3; a mercury vaporization chamber 42 that heats the dust collected by the dust collection unit 41 to vaporize mercury adhering to the dust; and a mercury adsorption chamber 43 that adsorbs mercury vaporized in the mercury vaporization chamber 42 to an adsorbent material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cement clinker production facility that produces cement clinker while removing mercury.

Background Art

[0002] When natural raw materials such as limestone, fuels such as coal and heavy oil, or wastes such as sludge and incineration ash used in the cement clinker production process contain mercury (including mercury compounds), mercury vaporizes into mercury gas in the high-temperature part of cement clinker production facilities such as rotary kilns. The exhaust gas containing mercury gas generated in this rotary kiln is sent to a raw material dryer or the like of a raw material preparation device for the purpose of using its waste heat for drying raw materials or the like. The exhaust gas after passing through the raw material dryer or the like is sent to a dust collection device such as a bag filter or an electrostatic precipitator, and the dust contained in the exhaust gas is collected. Mercury condenses and adheres to this dust as the temperature drops, or even if it does not condense, it is adsorbed to the dust (in the present invention, both are simply referred to as "adhesion" collectively). Therefore, by collecting this dust, mercury is removed from the exhaust gas. On the other hand, the collected dust is reused as a cement clinker raw material.

[0003] However, when the amount of mercury contained in the raw materials and fuels brought into the cement clinker production facility is large as described above, the mercury gas sent to the dust collection device together with the exhaust gas may not completely adhere to the dust and may be released into the atmosphere from the chimney together with the exhaust gas in that state.

[0004] As a solution to such problems, for example, Patent Document 1 discloses an invention related to a method capable of easily removing mercury contained in combustion exhaust gas generated in a cement production facility at low cost under the name of "Method for Removing Mercury from Combustion Exhaust Gas".

[0005] The invention disclosed in Patent Document 1 is characterized by introducing combustion exhaust gas discharged from the uppermost cyclone of a suspension preheater of a cement manufacturing facility into a coal drying and crushing device, adsorbing the mercury contained in the combustion exhaust gas onto the pulverized coal obtained by crushing the coal in the coal drying and crushing device, and then introducing the combustion exhaust gas and pulverized coal into a bag filter to collect only the pulverized coal, thereby purifying the combustion exhaust gas.

[0006] Thus, this mercury removal method, which uses a coal drying and crushing device that is an ancillary facility of cement manufacturing equipment, does not require the installation of a new mercury removal device, and therefore combustion exhaust gas can be easily and inexpensively purified.

[0007] Furthermore, Patent Document 2 discloses an invention titled "Method for treating exhaust gas from a cement kiln," which describes a method for removing mercury, organochlorine compounds, and dust from exhaust gas generated in a cement kiln where various types of waste are used as raw materials or fuel.

[0008] The invention disclosed in Patent Document 2 is characterized by extracting exhaust gas from a dust collector and sending it to an adsorption tower, adsorbing mercury and organochlorine compounds contained in the exhaust gas onto activated carbon or pulverized coal in the adsorption tower, then heating the activated carbon or pulverized coal to 400°C or higher in a heating furnace to remove mercury and organochlorine compounds, and finally feeding the activated carbon or pulverized coal obtained in this process into a cement kiln.

[0009] This method of treating exhaust gas from cement kilns allows for the miniaturization of the heating furnace used to remove mercury and organochlorine compounds, and reduces the energy required for heating. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2010-75784 [Patent Document 2] Japanese Patent Publication No. 2006-96615 [Overview of the project] [Problems that the invention aims to solve]

[0011] As described above, various methods have been proposed for removing mercury from exhaust gases generated by cement manufacturing facilities, but there is a need for new methods that can remove mercury more efficiently.

[0012] The object of the present invention is to provide a cement clinker manufacturing facility capable of efficiently removing mercury. [Means for solving the problem]

[0013] As a result of diligent research to solve the above problems, the inventors of the present invention have found that by collecting and recovering dust in exhaust gas and subjecting such dust to a predetermined treatment, mercury can be efficiently removed from exhaust gas and also efficiently removed from the cement clinker manufacturing system, thus completing the present invention.

[0014] In other words, the present invention is as follows: [1] A cement clinker manufacturing facility comprising a raw material preparation device, a calcination device, and a mercury removal device, The mercury removal device is A dust recovery device for collecting and recovering dust in the exhaust gas discharged from the raw material preparation device or calcination device, A mercury vaporization chamber heats the dust collected by the dust collection device to vaporize the mercury adsorbed on the dust, The system includes a mercury adsorption chamber for adsorbing mercury vaporized in the mercury vaporization chamber onto an adsorbent, The mercury adsorption chamber is It comprises an adsorbent holding section that holds the adsorbent material, and an adsorbent dispersing section provided above it that disperses the adsorbent material into the airflow, The adsorbent holding section includes an adsorbent discharge means for continuously or intermittently discharging the adsorbent on which mercury has been adsorbed, The adsorbent dispersion unit comprises a mercury gas introduction means for introducing mercury vaporized in the mercury vaporization chamber, an adsorbent introduction means for continuously or intermittently introducing additional adsorbent, and an airflow generation means. The airflow generating means comprises a gas circulation pipe, one end of which is positioned at the lower center of the adsorbent dispersion section, and which extends vertically from that end through the upper surface of the adsorbent dispersion section, with the other end extending through the side surface of the adsorbent dispersion section, and a gas circulation means for introducing gas from one end of the gas circulation pipe and discharging it from the other end. A cement clinker manufacturing facility characterized by the following features. [2] The cement clinker manufacturing apparatus according to [1], characterized in that it is equipped with an adsorbent circulation means for circulating a portion of the adsorbent discharged from the adsorbent discharge means to the adsorbent dispersion section. [3] The cement clinker manufacturing apparatus according to [1] or [2], characterized in that the capacity of the adsorbent holding section of the mercury adsorption chamber is smaller than the capacity of the mercury vaporization chamber.

[0015] [4] The cement clinker manufacturing apparatus according to any one of [1] to [3], characterized in that the mercury vaporization chamber is equipped with a heating means for maintaining the temperature inside the chamber at 370°C or higher, and the mercury adsorption chamber is equipped with a heating means for maintaining the temperature inside the chamber at more than 100°C and 200°C or lower. [5] A cement clinker manufacturing apparatus according to any one of [1] to [4], characterized in that the adsorbent is at least one selected from cement dust, fly ash, and coal ash. [6] The cement clinker manufacturing apparatus according to any one of [1] to [5], characterized in that the mercury removal apparatus includes a mercury separation and recovery apparatus for separating and recovering the mercury adsorbed on the adsorbent in the mercury adsorption chamber. [7] The cement clinker manufacturing apparatus according to [6], characterized in that the mercury separation and recovery apparatus is equipped with an adsorbent introduction means for introducing the adsorbent from which mercury has been separated into a raw material preparation apparatus or a calcination apparatus. [Effects of the Invention]

[0016] According to the manufacturing equipment of the cement clinker of the present invention, mercury can be efficiently removed from the exhaust gas, and mercury can be efficiently removed from the system.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic diagram showing the entire manufacturing equipment of the cement clinker according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of the mercury removal device of the cement clinker manufacturing equipment according to an embodiment of the present invention. [Figure 3] It is a schematic diagram of the mercury adsorption chamber of the mercury removal device of the cement clinker manufacturing equipment according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0018] The cement clinker manufacturing equipment of the present invention is a manufacturing equipment including a raw material preparation device, a firing device, and a mercury removal device. The mercury removal device includes a dust recovery device that collects and recovers dust in the exhaust gas discharged from the raw material preparation device or the firing device, a mercury vaporization chamber that heats the dust recovered by the dust recovery device to vaporize mercury (including mercury compounds. The same applies hereinafter) adsorbed on the dust, and a mercury adsorption chamber that adsorbs the mercury vaporized in the mercury vaporization chamber to the adsorbent. And this mercury adsorption chamber includes an adsorbent holding part that holds the adsorbent, and an adsorbent dispersion part that disperses the adsorbent in the air flow above it. The adsorbent holding part includes an adsorbent discharging means for continuously or intermittently discharging the adsorbent adsorbed with mercury, and the adsorbent dispersion part includes a mercury gas introducing means for introducing the mercury vaporized in the mercury vaporization chamber, an adsorbent feeding means for continuously or intermittently feeding additional adsorbent, and an air flow generating means. Further, this air flow generating means includes a gas circulation pipe whose one end is arranged at the lower center of the adsorbent dispersion part, penetrates the upper surface in the vertical direction from one end, and the other end penetrates the side surface of the adsorbent dispersion part, and a gas circulation means for introducing gas from one end of the gas circulation pipe and导出 it from the other end.

[0019] The raw material preparation equipment includes a raw material dryer and a raw material mill. The firing equipment includes a cyclone and a calcination furnace, and is equipped with a preheater section for calcining the cement clinker raw materials and a rotary kiln for the final firing of the calcined cement clinker raw materials.

[0020] In the present invention, the exhaust gas for recovering dust is not particularly limited as long as it is the gas before it is discharged into the atmosphere from the raw material preparation apparatus or the calcination apparatus. Preferably, it is the exhaust gas discharged from the rotary kiln of the calcination apparatus, and more preferably, it is the exhaust gas that has been discharged from the rotary kiln and then introduced into the raw material dryer of the raw material preparation apparatus before being discharged.

[0021] In the cement clinker manufacturing equipment of the present invention, mercury can be efficiently removed from exhaust gas and from the system by processing in a mercury removal device that includes a dust recovery device, a mercury vaporization chamber, and a mercury adsorption chamber. Furthermore, in the present invention, volatile heavy metals such as zinc, lead, and cadmium can be removed simultaneously with mercury.

[0022] The following describes a cement clinker manufacturing facility according to one embodiment of the present invention, using Figure 1 as a reference. Figure 1 is a schematic diagram showing the entire cement clinker manufacturing facility. In the figure, solid arrows represent the flow of raw materials moving through the cement clinker manufacturing facility, dotted arrows represent the flow of exhaust gas, and dashed arrows represent the flow of dust collected from the exhaust gas by the dust recovery device.

[0023] As shown in Figure 1, the cement clinker manufacturing facility 1 includes a raw material preparation device 2 for preparing cement clinker raw materials, a firing device 3 for firing the cement clinker raw materials prepared in the raw material preparation device 2, and a mercury removal device 4 for removing mercury from the exhaust gas.

[0024] The raw material preparation apparatus 2 comprises a raw material dryer 21, a raw material mill 22, a raw material mixing silo 23, and a raw material storage silo 24. Cement clinker raw materials are prepared using this raw material preparation apparatus 2 (raw material preparation process).

[0025] In the raw material preparation process, limestone, clay, silica, and iron oxide raw materials are mixed together and then sent to a raw material dryer 21 for drying. The raw material dryer 21 dries the raw materials using high-temperature exhaust gas sent from the calcination device 3. Subsequently, the materials are sent to a raw material mill 22 for grinding. The materials ground in the raw material mill 22 are sent to a raw material mixing silo 23 for homogeneous blending and then stored in a raw material storage silo 24. Meanwhile, the exhaust gas discharged from the raw material dryer 21 is sent to a hydrogen removal device 4.

[0026] The firing apparatus 3 comprises multiple cyclones 31 and a calcination furnace 32, and includes a preheater section 33 for calcining the cement clinker raw material, a rotary kiln 34 for main firing the calcined cement clinker raw material, and a clinker cooler 35 for cooling the fired cement clinker. The firing of the cement clinker raw material is carried out using this firing apparatus 3 (firing process).

[0027] In the firing process, the powdered raw materials, which have been dried and crushed in the raw material preparation process, are sent to the preheater section 33 and pre-fired. The rotary kiln 34 is provided with a gentle slope, and the powdered raw materials preheated in the preheater section 33 are fired at a high temperature (for example, about 1450°C) as they slowly move through the rotary kiln 34 due to this slope and rotational motion. The powdered raw materials fired in the rotary kiln 34 are rapidly cooled in the clinker cooler 35 to become a black, lumpy fired product called cement clinker.

[0028] Following the firing process, a finishing process is carried out in which gypsum and other materials are added to the manufactured cement clinker, thereby producing cement.

[0029] Next, we will explain the main flow of exhaust gas in the cement clinker manufacturing process. As shown by the dotted arrow in Figure 1, the exhaust gas generated in the rotary kiln 34 rises through the inside of the preheater section 33 in the opposite direction to the flow of the powdered raw material and is discharged from the uppermost cyclone 31. This exhaust gas is then sent to the raw material dryer 21 to utilize its residual heat for drying the raw material. The exhaust gas discharged from the raw material dryer 21 is sent to the mercury removal device 4, where mercury (mercury-containing dust) is removed, and then it is released into the atmosphere through the chimney 5. Therefore, the exhaust gas released to the outside contains almost no mercury.

[0030] Furthermore, since mercury vaporizes into mercury gas inside the preheater section 33 and the rotary kiln 34, it is not included in the cement clinker sent to the finishing process.

[0031] Next, the mercury removal device 4 will be described using Figures 2 and 3. Figure 2 is a schematic diagram of the mercury removal device for a cement clinker manufacturing facility according to one embodiment of the present invention, and Figure 3 is a schematic diagram of the mercury adsorption chamber of the mercury removal device.

[0032] As shown in Figure 2, the mercury removal device 4 comprises a dust collection device 41, a mercury vaporization chamber 42, a mercury adsorption chamber 43, and a mercury separation and recovery device 44.

[0033] (Dust collection device) The dust collection device 41 includes a bag filter 45 (first bag filter), a cyclone 46 for classifying the dust collected from the bag filter 45, and a bag filter 47 (second bag filter) for collecting the fine dust particles obtained by the classification by the cyclone 46.

[0034] First, the exhaust gas discharged from the raw material dryer 21 has its dust recovered by the bag filter 45. A portion of this recovered dust is sent to the cyclone 46, and the remaining dust is returned to the system of the clinker manufacturing plant 1. In the cyclone 46, particulate dust is separated, and the particulate dust is recovered by the bag filter 47. The relatively heavier dust is returned to the system of the clinker manufacturing plant 1. Since the particulate dust has a high mercury concentration, removing it allows for efficient removal of mercury.

[0035] Furthermore, the dust collection device is not particularly limited as long as it can collect dust from the exhaust gas; in addition to bag filters, electrostatic precipitators can be used. To collect fine particulate dust, it is preferable to combine it with a cyclone (powder separator) as needed. When using a multi-stage electrostatic precipitator, it is preferable to collect dust from the later stages in order to collect fine particulate dust with a high mercury concentration.

[0036] (Mercury vaporization chamber) The mercury vaporization chamber 42 is a means of heating the dust containing high concentrations of mercury, which has been recovered by the dust recovery device 41, to vaporize the mercury attached to the dust. The mercury vaporization process is carried out in this mercury vaporization chamber 42.

[0037] The mercury vaporization chamber 42 is equipped with a heating means and a stirring means. Dust introduced into the mercury vaporization chamber 42 is heated while being stirred, vaporizing the mercury attached to the dust to form mercury gas. Dust is continuously or intermittently introduced into the mercury vaporization chamber 42 from the bag filter 47 of the dust recovery device 41. The mercury gas vaporized in the mercury vaporization chamber 42 is sent downstream to the mercury adsorption chamber 43 along with the carrier gas. The dust from which mercury has been removed in the mercury vaporization chamber 42 is continuously or intermittently discharged and returned to the system of the cement clinker manufacturing facility 1.

[0038] The capacity of the mercury vaporization chamber can be, for example, 0.5 to 20 m³. 3 And, 1 to 10m 3It is preferable that the mercury vaporization chamber be heated to a temperature of 370°C or higher, more preferably 400°C or higher, and even more preferably 450°C or higher. By heating to a temperature within this range, mercury can be effectively vaporized and removed from the dust, since the boiling point of mercury is 356°C.

[0039] (Mercury adsorption chamber) The mercury adsorption chamber 43 is a means of adsorbing mercury (mercury gas) vaporized in the mercury vaporization chamber 42 onto an adsorbent. The mercury adsorption process is carried out in this mercury adsorption chamber 43.

[0040] The mercury adsorption process specifically involves, for example, introducing vaporized mercury gas into a mercury adsorption chamber, dispersing a predetermined amount of adsorbent material into the airflow to adsorb mercury onto the adsorbent material, while simultaneously introducing additional adsorbent material continuously or intermittently, and continuously or intermittently discharging the adsorbent material on which mercury has been adsorbed.

[0041] The mercury adsorption chamber 43 is an airflow mixing type chamber, as shown in Figures 2 and 3, for example, and comprises an adsorbent holding section 49 for holding the adsorbent and an adsorbent dispersion section 50 located above it for dispersing the adsorbent into the airflow. In other words, the adsorbent is dispersed into the airflow, mercury gas is blown into it, and mercury is adsorbed by the adsorbent.

[0042] The adsorbent holding section 49 is equipped with an adsorbent discharge means 51 for continuously or intermittently discharging the adsorbent on which mercury has been adsorbed. The adsorbent dispersion section 50 is equipped with a mercury gas introduction means 52 for introducing mercury vaporized in the mercury vaporization chamber 42, an adsorbent introduction means 53 for continuously or intermittently introducing additional adsorbent, and an airflow generation means 54. The airflow generation means 54 is equipped with a gas circulation pipe 55, one end of which is positioned at the lower center of the adsorbent dispersion section 50, with the other end penetrating the upper surface of the adsorbent dispersion section 50 in a vertical direction from the one end and penetrating the side surface of the adsorbent dispersion section 50, and a gas circulation means (fan) 56 for introducing gas from one end of the gas circulation pipe 55 and discharging it from the other end.

[0043] The other end of the gas circulation pipe 55 is preferably installed so that gas can be discharged from the side of the adsorbent dispersion section 50 in a direction along the peripheral wall surface. Similarly, the mercury gas introduction means 52 is preferably installed so that mercury gas can be introduced from the side of the adsorbent dispersion section 50 in a direction along the peripheral wall surface. This allows the adsorbent (and the introduced mercury gas) to swirl and disperse effectively, enabling efficient adsorption of mercury onto the adsorbent. Furthermore, the adsorbent adheres to and covers the peripheral wall surface, preventing mercury from adhering to the peripheral wall surface and thus preventing mercury from adhering to the peripheral wall surface during cooling.

[0044] Furthermore, it is preferable that the mercury adsorption chamber 43 is equipped with an adsorbent circulation means 57 that circulates a portion of the adsorbent discharged from the adsorbent discharge means 51 back to the adsorbent dispersion section 50. Specifically, it can be circulated back to the adsorbent input means 53 of the adsorbent dispersion section 50. This further improves the uniformity of mercury adhesion to the adsorbent and allows for more efficient adsorption of mercury onto the adsorbent.

[0045] The capacity of the adsorbent holding section of the mercury adsorption chamber is preferably smaller than that of the mercury vaporization chamber, preferably 1 / 2 or less, more preferably 1 / 3 or less, and even more preferably 1 / 4 or less. The lower limit can be determined appropriately considering the processing efficiency, but for example, it is 1 / 20 or more.

[0046] The volume of the adsorbent used is preferably less than the volume of the treated dust, preferably 1 / 2 or less, more preferably 1 / 5 or less, and even more preferably 1 / 10 or less. The lower limit can be appropriately determined considering the mercury recovery efficiency, but for example, it is 1 / 50 or more. This allows for the concentration and recovery of mercury, and enables efficient subsequent mercury separation and recovery treatment and disposal of the adsorbent.

[0047] Furthermore, it is preferable to maintain the temperature inside the mercury adsorption chamber between 100°C and 200°C by a heating means, more preferably between 110°C and 180°C, and even more preferably between 120°C and 150°C. Maintaining the temperature within this range allows the mercury gas to be sufficiently cooled and adsorbed by the adsorbent. In addition, although the adsorbent often contains moisture, in this case the moisture is discharged as water vapor, so the inside of the mercury adsorption chamber can be kept dry, and the adsorbent can be prevented from adhering to the inner wall of the chamber.

[0048] Here, the adsorbent is not particularly limited as long as it can adsorb mercury, and cement dust, fly ash, coal ash, etc., can be used. Among these, coal ash is preferred because it is lightweight and has high adsorption performance. When cement dust is used as the adsorbent, dust recovered by the bag filter 45 may be used, but it is preferable to use particulate dust recovered by the bag filter 47 (particulate dust introduced into the mercury vaporization chamber).

[0049] Furthermore, as shown in Figure 3, it is preferable that the mercury gas introduction means 52 is equipped with a heating means 52b and an insulating material 52c around the gas vent pipe 52a to maintain a high temperature (for example, 370°C or higher) until the tip (just before discharge). This prevents the gas vent pipe 52a from becoming blocked due to solidification of heavy metal-containing gases such as mercury gas.

[0050] The exhaust gas discharged from the mercury adsorption chamber 43 may be treated with activated carbon or the like and released into the atmosphere, but it is preferable to return it to the cement clinker manufacturing facility 1 in order to utilize the residual heat.

[0051] (Mercury separation and recovery device) It is preferable to separate and recover the mercury adsorbed onto the adsorbent in the mercury adsorption chamber using a mercury separation and recovery device. For example, as shown in Figure 2, a mercury separation and recovery device 44 can be provided, which includes a first heating furnace (heating furnace) 58 for raising the temperature of the introduced adsorbent, a second heating furnace (constant temperature furnace) 59 for maintaining the high temperature state of the adsorbent and separating mercury from the adsorbent, and a cooler 60 for cooling the adsorbent from which the mercury has been separated. Specifically, a so-called Hagenmeyer furnace can be used as the mercury separation and recovery device 44, which allows for the simultaneous decomposition of dioxins.

[0052] The first heating furnace 58 and the second heating furnace 59 are designed to allow the introduction of an inert gas such as nitrogen gas. The inert gas creates an oxygen-deficient environment inside the furnace with an oxygen concentration of 0.1% or less, and the furnace is heated to a temperature of approximately 400°C to 600°C under this oxygen-deficient reducing atmosphere. During the heat treatment in the first heating furnace 58 and the second heating furnace 59, mercury, which has a boiling point of 356°C, vaporizes into mercury gas, thus separating the mercury from the adsorbent. Furthermore, no mercury oxide or mercury chloride is produced, and the mercury can be recovered in the form of metallic mercury.

[0053] The mercury gas (and steam) generated in the second heating furnace 59 is cooled, and metallic mercury is recovered in the metallic mercury recoverer 61. The metallic mercury recoverer 61 is structured so that mercury, which has a higher specific gravity than water, accumulates at the bottom, and water, which has a lower specific gravity than mercury, accumulates above the mercury, thereby enabling the recovery of metallic mercury.

[0054] Meanwhile, in the cooler 60, the adsorbent removed from the second heating furnace 59 and from which mercury has been removed is cooled to about 70°C. If the cooling rate is slow, the decomposed dioxins will be resynthesized at around 250°C, so it is preferable to cool it rapidly (for example, to 70°C in about 60 minutes). This suppresses the resynthesis of dioxins.

[0055] It is preferable to return the adsorbent from which mercury has been separated, cooled in the cooler 60, back into the system of the cement clinker manufacturing equipment 1. That is, it is preferable that the mercury separation and recovery device 44 is equipped with an adsorbent introduction means 62 for introducing the adsorbent from which mercury has been separated into the raw material preparation device 2 or the calcination device 3. This allows the adsorbent from which mercury has been separated in the mercury separation and recovery device to be used in the cement clinker manufacturing process, and the adsorbent can be effectively utilized as a raw material for cement clinker. [Examples]

[0056] [Example 1] The following study examined the relationship between dust particle size and the mercury content contained in the dust. Specifically, the dust collected by the bag filter 45 (first bag filter) was classified using cyclone 46, and the relationship between particle size and mercury concentration was investigated. The results are shown in Table 1. Note that "D10," "D50," and "D90" in the table represent the particle sizes at which the cumulative frequency reaches 10%, 50%, and 90%, respectively.

[0057] [Table 1]

[0058] As is clear from Table 1, the mercury concentration of the dust before classification was 28.0 ppm, while the mercury concentration of the dust after classification was approximately 0.8 times lower for coarse powder (D50 = 17.79 μm) and approximately 1.6 times higher for fine powder (D50 = 2.91 μm). This means that in order to reduce the amount of mercury contained in raw materials and fuels introduced into the cement manufacturing process that circulates in the raw material preparation and firing processes, it is effective to remove the mercury contained in the fine particle dust (corresponding to the fine powder shown in Table 1) obtained by classifying the dust recovered from the bag filter 45 (first bag filter).

[0059] [Example 2] Next, the effectiveness of mercury removal using the mercury removal device of the present invention (mercury vaporization chamber and mercury adsorption chamber) was confirmed. Specifically, 4200 cm³ of fine dust collected in bag filter 47 (second bag filter) 3 (2772g), 4000cm² to the first dust 3 (2640g) and 200cm in the second dust 3 The first dust was divided into 132g portions and supplied to a mercury vaporization chamber 42. It was heated to approximately 500°C to vaporize the mercury, and this mercury gas was brought into contact with the second dust, which was used as an adsorbent, in a mercury adsorption chamber 43 at approximately 120°C to recover the second dust containing a high concentration of mercury. The results are shown in Table 2.

[0060] [Table 2]

[0061] As is clear from Table 2, the mercury concentration in the first and second dust samples during preparation was 44.2 ppm, while the mercury concentration in the first dust sample after extraction was 0.6 ppm, and in the second dust sample (adsorbent) it was 637.7 ppm (concentration ratio approximately 14 times). Therefore, according to the method of the present invention, a high concentration of mercury can be adsorbed and recovered using a small amount of adsorbent, making it possible to reduce the processing volume in subsequent mercury separation treatments and the like.

[0062] [Example 3] In Example 2, coal ash was used instead of the second dust used as the adsorbent to confirm the effectiveness of mercury removal using the mercury removal apparatus (mercury vaporization chamber and mercury adsorption chamber) of the present invention. The coal ash used was obtained from a thermal power generation facility within Tokuyama Corporation and processed using a 90 μm vibrating screen. The loose bulk density of the sieved coal ash obtained in this way was 0.51 g / cm³. 3 That was the case.

[0063] Specifically, the fine dust obtained in Example 1 was supplied to the mercury vaporization chamber 42, and the coal ash was supplied to the mercury adsorption chamber 43. The mercury vaporization chamber 42 was heated to approximately 500°C to gasify the mercury, and the mercury gas was brought into contact with the coal ash, which was used as an adsorbent, in the mercury adsorption chamber 43 at approximately 120°C to recover coal ash containing a high concentration of mercury. The results are shown in Table 3.

[0064] [Table 3]

[0065] As is clear from Table 3, the mercury concentrations of the fine dust and coal ash used in the initial preparation were 44.2 ppm and 2.2 ppm, respectively, while the mercury concentration of the extracted fine dust was 0.7 ppm, and the coal ash (adsorbent) had a mercury concentration of 478.8 ppm (concentration ratio of approximately 11 times). Therefore, according to the method of the present invention, a high concentration of mercury can be adsorbed and recovered using a small amount of adsorbent, making it possible to reduce the processing volume in subsequent processes such as mercury separation treatment. [Industrial applicability]

[0066] The cement clinker manufacturing equipment of the present invention is industrially useful because it can produce cement clinker while suppressing the emission of mercury into the atmosphere. [Explanation of symbols]

[0067] 1…Cement clinker manufacturing equipment 2...Raw material preparation equipment 3…Firing apparatus 4…Mercury removal equipment 5… Chimney 21...Raw material dryer 22… Raw material mill 23… Raw material mixing silo 24… Raw material storage silo 31...Cyclone 32... Temporary Firing Furnace 33… Preheater section 34…Rotary Kiln 35... Klinka Cooler 41... Dust collection device 42…Mercury vaporization chamber 43…Mercury adsorption chamber 44…Mercury separation and recovery device 45... Bug filter (First bug filter) 46...Cyclone 47... Bug filter (Second bug filter) 49...Adsorbent holding part 50...Adsorbent dispersion section 51...Adsorbent discharge means 52...Methods for introducing mercury gas 52a...Gas vent pipe 52b...Heating means 52c…Heat insulation material 53…Adsorbent feeding means 54... Airflow generation means 55...Gas circulation pipe 56... Gas circulation means (fan) 57...Adsorbent circulation means 58…First heating furnace (temperature rise furnace) 59…Second heating furnace (constant temperature furnace) 60...Cooler 61…Metal mercury recovery device 62…Method for introducing adsorbent

Claims

1. A cement clinker manufacturing facility comprising a raw material preparation device, a calcination device, and a mercury removal device, The mercury removal device is A dust recovery device for collecting and recovering dust in the exhaust gas discharged from the raw material preparation device or calcination device, A mercury vaporization chamber heats the dust collected by the dust collection device to vaporize the mercury adsorbed on the dust, The system includes a mercury adsorption chamber for adsorbing mercury vaporized in the mercury vaporization chamber onto an adsorbent, The mercury adsorption chamber is It comprises an adsorbent holding section that holds the adsorbent material, and an adsorbent dispersing section provided above it that disperses the adsorbent material into the airflow, The adsorbent holding section includes an adsorbent discharge means for continuously or intermittently discharging the adsorbent on which mercury has been adsorbed, The adsorbent dispersion unit comprises a mercury gas introduction means for introducing mercury vaporized in the mercury vaporization chamber, an adsorbent introduction means for continuously or intermittently introducing additional adsorbent, and an airflow generation means. The airflow generating means comprises a gas circulation pipe, one end of which is positioned at the lower center of the adsorbent dispersion section, and which extends vertically from that end through the upper surface of the adsorbent dispersion section, with the other end extending through the side surface of the adsorbent dispersion section, and a gas circulation means for introducing gas from one end of the gas circulation pipe and discharging it from the other end. A cement clinker manufacturing facility characterized by the following features.

2. The cement clinker manufacturing apparatus according to claim 1, further comprising an adsorbent circulation means for circulating a portion of the adsorbent discharged from the adsorbent discharge means to the adsorbent dispersion section.

3. The cement clinker manufacturing apparatus according to claim 1 or 2, characterized in that the capacity of the adsorbent holding section of the mercury adsorption chamber is smaller than the capacity of the mercury vaporization chamber.

4. The cement clinker manufacturing apparatus according to claim 1 or 2, characterized in that the mercury vaporization chamber is equipped with a heating means for maintaining the temperature inside the chamber at 370°C or higher, and the mercury adsorption chamber is equipped with a heating means for maintaining the temperature inside the chamber at more than 100°C and less than or equal to 200°C.

5. The cement clinker manufacturing apparatus according to claim 1 or 2, characterized in that the adsorbent is at least one selected from cement dust, fly ash, and coal ash.

6. The cement clinker manufacturing apparatus according to claim 1 or 2, characterized in that the mercury removal apparatus includes a mercury separation and recovery apparatus for separating and recovering mercury adsorbed on the adsorbent in the mercury adsorption chamber.

7. The cement clinker manufacturing apparatus according to claim 6, characterized in that the mercury separation and recovery apparatus is equipped with an adsorbent introduction means for introducing the adsorbent from which mercury has been separated into a raw material preparation apparatus or a calcination apparatus.

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