JP7120766B2 - Exhaust gas treatment device - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an exhaust gas treatment device for treating exhaust gas discharged from a cement manufacturing facility.

Cement raw materials (eg, limestone, coal, silica stone, clay, iron oxide raw materials, some waste products, etc.) may contain mercury. Since mercury has a great adverse effect on the human body, the environment, etc., various proposals have been made to reduce mercury emissions in the process of producing cement from cement raw materials. For example, Patent Literature 1 discloses an exhaust gas treatment apparatus provided with an adsorbent addition device configured to put a mercury adsorbent (activated carbon or the like) inside a bag filter. Mercury exists in the form of, for example, metallic mercury and mercury chloride in cement manufacturing facilities.

JP 2017-001930 A

In recent years, the Minamata Convention on Mercury has come into force, and the international trend is to control mercury emissions even more strictly. Therefore, there is a need to further reduce mercury emissions from cement manufacturing facilities. According to the device described in Patent Document 1, although the amount of mercury emissions can be reduced, in addition to requiring a mercury adsorbent for recovering mercury, the mercury adsorbent with adsorbed mercury must be treated. , running costs tend to be high. Furthermore, the mercury adsorbent charged into the apparatus circulates within the apparatus and mixes with the cement raw material, which may raise concerns about the quality of the manufactured cement.

Therefore, the present disclosure describes an exhaust gas treatment apparatus capable of recovering heavy metals without using an adsorbent and stably suppressing heavy metal emissions to a low level.

Example 1. An exhaust gas treatment apparatus according to one example of the present disclosure includes a cement calcining furnace configured to calcine cement raw materials to produce cement clinker, and a cement calcining furnace configured to cool the gas generated inside the cement clinker by the calcination. and a recovering means configured to recover the heavy metals in the gas and the particulate matter adhering to the surface of the cooler as the gas is cooled by the cooler.

Cement raw materials are heated to about 1450° C. in the cement kiln. Therefore, the heavy metals contained in the cement raw material are gaseous or liquid in the cement calcining furnace, and are discharged downstream along with the combustion gas and fine powder generated in the cement calcining furnace. When the gas discharged from the cement kiln comes into contact with the cooler on the downstream side, the gas is cooled by the cooler, and the fine powder aggregates on the surface of the cooler and deposits as granules. At this time, the gaseous or liquid heavy metal accompanying the combustion gas and the fine powder is also cooled, so that the heavy metal changes into a liquid or solid state and is involved in the agglomerated fine powder. Therefore, the heavy metal contained in the granular material is also recovered by recovering the granular material deposited on the surface of the cooler by the recovering means. Therefore, according to the apparatus of Example 1, heavy metals can be recovered without using an adsorbent, and the amount of heavy metal emissions can be stably suppressed to a low level.

Example 2. In the apparatus of Example 1, the cement kiln includes a rotary kiln configured to calcine the cement raw material, and a preheater configured to preheat the cement raw material using the kiln exhaust gas discharged from the rotary kiln. and the cooler may be configured to cool preheater exhaust gas discharged from the preheater. Preheater exhaust gas is generally about 400° C., which tends to be higher than the boiling point or melting point of heavy metals. Therefore, while the heat of the kiln exhaust gas is used for preheating the cement raw material, heavy metals are recovered from the gas generated inside the cement kiln in the cooler. Therefore, it is possible to achieve both effective use of thermal energy and recovery of heavy metals.

Example 3. The apparatus of Example 2 may further comprise a boiler that uses the preheater exhaust gas discharged from the preheater to generate steam, and the cooler is configured to cool the boiler exhaust gas discharged from the boiler. Boiler exhaust gas generally has a temperature of about 300° C. or lower, which tends to be higher than the boiling point or melting point of heavy metals. Therefore, heavy metals are recovered from the gas generated inside the cement kiln in the cooler while the heat of the exhaust gas from the preheater is used to generate steam. Therefore, it is possible to achieve both effective use of thermal energy and recovery of heavy metals.

Example 4. In the apparatus of any one of Examples 1-3, the temperature of the gas introduced into the cooler may be 300° C. or less. If the temperature of the gas introduced into the cooler is 300° C. or less, the temperature of the gas tends to be lower than the boiling point or melting point of the heavy metal due to contact with the cooler. Therefore, compared to the case where the gas introduced into the cooler exceeds 300° C., the concentration of heavy metals contained in the particles deposited on the surface of the cooler tends to increase. Therefore, it becomes possible to recover heavy metals more effectively.

Example 5. In the apparatus of any one of Examples 1-4, the temperature of the chiller exhaust gas discharged from the chiller may be 100° C. or higher. In this case, the thermal energy of the cooler exhaust gas can be effectively utilized by introducing the cooler exhaust gas discharged from the cooler into other equipment.

Example 6. In the apparatus of any one of Examples 1 to 5, the cooler may be a pipe configured to allow a cooling fluid to flow. In this case, it is possible to configure the cooler extremely simply.

Example 7. In the device of Example 6, the fluid may be air or water. In this case, it is possible to very easily recover the heat of the gas generated inside the cement kiln.

Example 8. In the apparatus of Examples 6 or 7, piping may connect the chiller to other equipment located downstream of the chiller. In this case, the heat recovered by the fluid from the gas generated inside the cement kiln can be effectively utilized in the other equipment.

Example 9. The apparatus of Example 8 further includes a fermenter configured to ferment organic sludge, a pipe connects the cooler and the fermenter, and the inside of the pipe heated by heat exchange with gas of fluid into the fermenter. In this case, the heat recovered by the fluid from the gas generated inside the cement kiln can be utilized for fermentation of the organic sludge in the fermentation machine.

Example 10. In the apparatus of any one of Examples 1 to 9, the recovering means may be configured to drop the granules adhering to the surface of the cooler from the surface of the cooler. In this case, it becomes possible to easily recover the heavy metal together with the powder.

Example 11. In the apparatus of any one of Examples 1 to 10, the recovery means is a blower configured to blow gas onto the surface of the cooler or a vibrator configured to apply vibration to the cooler. may

Example 12. The apparatus of any one of Examples 1-11 may further comprise a dryer configured to dry the cement raw material using chiller exhaust gas discharged from the chiller. In this case, it is possible to effectively utilize the thermal energy of the cooler exhaust gas discharged from the cooler in the dryer.

Example 13. The apparatus of any one of Examples 1-12 may further comprise bleed means configured to partially introduce the gas into the chiller. In this case, since the amount of gas to be cooled in the cooler is limited by the bleed means, there is no need to increase the cooling capacity of the cooler more than necessary. Therefore, it is possible to suppress the construction cost of the exhaust gas treatment device while stably suppressing the emission of heavy metals to a low level.

Example 14. The apparatus of any one of Examples 1 to 13 further comprises first and second housings including interior spaces containing coolers, the first and second housings diverging gas into each It may be configured to be introduced into each of the internal spaces. In this case, when collecting the granular material in the first housing, by stopping the introduction of the gas into the first housing and introducing the gas into the second housing, the second housing It becomes possible to continue cooling the gas with the body cooler.

Example 15. In the apparatus of any one of Examples 1-14, the heavy metal may be mercury or a mercury compound.

According to the exhaust gas treatment apparatus according to the present disclosure, it is possible to recover heavy metals without using an adsorbent and stably suppress heavy metal emissions to a low level.

FIG. 1 is a block diagram showing an example of a clinker manufacturing apparatus. FIG. 2 is a diagram schematically showing an example of a dust box. FIG. 3 is a graph showing the vapor pressure of metallic mercury versus temperature. FIG. 4 is a cross-sectional view for explaining how powder particles adhere to a pipe. FIG. 5 is a graph showing the relationship between the temperature of the exhaust gas when heat is exchanged with the fluid flowing through the pipe and the concentration of mercury deposited on the surface of the pipe at that temperature. FIG. 6 is a diagram schematically showing another example of the dust box. FIG. 7 is a diagram schematically showing another example of the dust box.

Since the embodiments according to the present disclosure described below are examples for explaining the present invention, the present invention should not be limited to the following contents. In the following description, the same reference numerals will be used for the same elements or elements having the same functions, and redundant description will be omitted.

[Configuration of clinker manufacturing equipment]
The configuration of the clinker manufacturing apparatus 1 will be described with reference to FIGS. 1 to 4. FIG. The clinker production apparatus 1 is a part of cement production equipment, and as shown in FIG. 1, is an apparatus for producing cement clinker M5 from cement raw material M1. The clinker production apparatus 1 also has a function of internally treating the exhaust gas discharged from itself, and also operates as an exhaust gas treatment apparatus. The clinker manufacturing apparatus 1 includes a raw material storage area 10, a dryer 12 (dryer), a crusher 14 (dryer), a silo 16, an SP (suspension preheater) 18 (preheater; cement kiln), and a rotary kiln. 20 (a cement kiln), a boiler 22, a dust box 24, a dust collector 26, and a fermentation machine 28.

The raw material storage space 10 is configured to store the cement raw material M1. The cement raw material M1 is, for example, a mixture of limestone, coal ash, silica stone, clay, iron oxide raw material, waste, etc., and has a size of several centimeters to ten and several centimeters. These cement raw materials M1 may contain heavy metals (for example, mercury, mercury compounds, lead, thallium, etc.). The boiling point of metallic mercury is about 356.7°C, the boiling point of mercury chloride is about 302°C, the boiling point of lead is about 1749°C, and the boiling point of thallium is about 1473°C. The melting point of metallic mercury is about -38.83°C, the melting point of mercury chloride is about 277°C, the melting point of lead is about 327.5°C, and the melting point of thallium is about 304°C. Note that FIG. 3 is a graph of the vapor pressure of metallic mercury based on the description in the chemical handbook. As shown in FIG. 3, the vapor pressure of metallic mercury is significantly reduced below 300.degree. That is, it is understood that the amount of metallic mercury present in a gaseous state is greatly reduced at 300° C. or lower, and that at approximately 150° C. or lower, the amount of metallic mercury present in a gaseous state is almost eliminated.

The dryer 12 is configured to supply hot air (for example, about 400° C.) to the cement raw material M1 introduced from the raw material storage site 10 to dry the cement raw material M1. The cement raw material M1 dried by the dryer 12 becomes the dry raw material M2. Dust box exhaust gas G6, which is exhaust gas from the dust box 24, is introduced into the dryer 12 and used for drying the cement raw material M1. On the other hand, dryer exhaust gas G7 (dryer exhaust gas), which is exhaust gas from the dryer 12, is introduced into the dust collector . The temperature of the dryer exhaust gas G7 when it is introduced into the dust collector 26 is, for example, about 90°C.

The pulverizer 14 is configured to pulverize the dry raw material M2 introduced from the dryer 12 . Examples of the pulverizer 14 include a vertical roller mill and a ball mill. The dry raw material M2 is pulverized into particles of 300 μm or less by the pulverizer 14 to become the granular raw material M3. When the dry raw material M2 is pulverized in the pulverizer 14, the dry raw material M2 contacts with the dust box exhaust gas G4, which is the exhaust gas from the dust box 24, and is further dried. Granular raw material M3 is then introduced into silo 16 .

On the other hand, pulverizer exhaust gas G5 (dryer exhaust gas), which is the exhaust gas from the pulverizer 14, is introduced into the dust collector 26. As shown in FIG. The temperature of the pulverizer exhaust gas G5 when it is introduced into the dust collector 26 is, for example, about 90°C.

The silo 16 is configured to temporarily store the granular raw material M3 from the crusher 14 . The silo 16 supplies the granular raw material M3 to the SP 18 in a timely manner.

The SP 18 is a device for preheating the granular raw material M3 in the rotary kiln 20 for the purpose of increasing the raw material firing efficiency, and constitutes a part of the cement firing furnace 2 . The SP 18 has a plurality of stages (for example, about 4 to 5 stages) of cyclones (separators). Granular raw material M3 is charged to the top of SP18. Kiln exhaust gas G1 (gas), which is the exhaust gas from the rotary kiln 20, is introduced from the tower bottom of SP18. The kiln exhaust gas G1 and the granular raw material M3 are sequentially heat-exchanged in each stage of the cyclone, and the granular raw material M3 is preheated to, for example, about 850° C. to become the kiln raw material M4. The kiln raw material M4 produced in SP18 is discharged from the tower bottom and introduced into the rotary kiln 20.

On the other hand, the SP exhaust gas G2 (preheater exhaust gas; gas), which is the exhaust gas from the SP18, is discharged from the tower top of the SP18. The SP exhaust gas G2 is, for example, about 400°C. The SP 18 may be a New Suspension Preheater (NSP) further comprising a calciner provided between the bottom stage of the cyclone and the rotary kiln 20 . According to the NSP, fuel (for example, pulverized coal) is supplied to the calcining furnace to calcine the granular raw material M3, so the production amount and firing efficiency of the kiln raw material M4 are improved.

The rotary kiln 20 is configured to calcine the kiln raw material M4 introduced from SP18 at a high temperature to produce cement clinker M5. The rotary kiln 20 forms part of the cement kiln 2 . The maximum temperature of the rotary kiln 20 is usually over 2000°C. Therefore, in the rotary kiln 20, the kiln raw material M4 is heated to about 1450° C., for example. Kiln exhaust gas G1 internally generated by firing in the rotary kiln 20 is introduced into SP18. The temperature of the kiln exhaust gas G1 when it is introduced into the SP18 is, for example, about 900.degree. C. to 1250.degree.

Since the temperature inside the rotary kiln 20 is higher than the boiling point of heavy metals, the heavy metals contained in the kiln raw material M4 introduced into the rotary kiln 20 are gaseous or liquid inside the rotary kiln 20 . Therefore, gaseous or liquid heavy metals are discharged toward SP18 together with kiln exhaust gas G1 and fine powder.

The boiler 22 is configured to exchange heat with the SP exhaust gas G2 to generate steam. Steam obtained in the boiler 22 is introduced into the power generation turbine. Therefore, part of the heat of the SP exhaust gas G2 is recovered in the boiler 22 as electrical energy. Boiler exhaust gas G<b>3 (gas), which is exhaust gas from the boiler 22 , is introduced into the dust box 24 . The temperature of the boiler exhaust gas G3 when introduced into the dust box 24 may be, for example, 300° C. or lower, 275° C. or lower, 250° C. or lower, or 210° C. or lower. There may be.

If the temperature of the boiler exhaust gas G3 when introduced into the dust box 24 is 300° C. or less, the boiler exhaust gas G3 contacts the pipe 34 and tends to drop below the boiling point or melting point of heavy metals. Therefore, compared to the case where the temperature of the boiler exhaust gas G3 exceeds 300° C. when introduced into the dust box 24, the concentration of heavy metals contained in the particulate matter P deposited on the surface of the pipe 34 tends to increase. Therefore, it becomes possible to recover heavy metals more effectively.

The dust box 24 is configured to collect heavy metals in the boiler exhaust gas G3. Specifically, as shown in FIG. 2, the dust box 24 includes a housing 30, a supply source 32 (cooler), a pipe 34 (cooler), and a collector 36 (collector).

The housing 30 accommodates a portion of the pipe 34 in its internal space. Boiler exhaust gas G3 is introduced into the housing 30 . From the housing 30, dust box exhaust gases G4 and G6, which are exhaust gases after heat exchange with the piping 34, are discharged. The temperature of the dust box exhaust gas G4, G6 may be, for example, 100° C. or higher, 125° C. or higher, or 150° C. or higher. When the temperature of the dust box exhaust gas G4 is 100° C. or higher, the heat energy of the dust box exhaust gas G4, G6 can be effectively utilized by introducing the dust box exhaust gas G4, G6 into other equipment.

The supply source 32 is configured to supply the fluid F to the pipe 34 and circulate the fluid F downstream through the pipe 34 . As the fluid F, various fluids that are liquid or gaseous at room temperature can be used. In this case, the heat of the boiler exhaust gas G3 can be recovered very easily. The temperature of the fluid F when it is supplied from the supply source 32 to the pipe 34 may be normal temperature, for example.

A portion of the pipe 34 passes through the internal space of the housing 30 . The portion of the pipe 34 may meander within the interior space of the housing 30, as shown in FIG. The upstream end of pipe 34 is connected to supply source 32 . The downstream end of pipe 34 is connected to SP18. Therefore, the fluid F after heat exchange with the boiler exhaust gas G3 in the internal space of the housing 30 is introduced into the SP18. The heat of the fluid F is used as part of the heat source for preheating the combustion air of the burner in SP18. Therefore, it is possible to save energy by reducing the amount of fuel used in SP18.

Here, the heavy metals that have become gaseous or liquid in the rotary kiln 20 are sequentially accompanied with fine powder in the kiln exhaust gas G1, the SP exhaust gas G2, and the boiler exhaust gas G3 while remaining gaseous or liquid, or changing from the gaseous state to the liquid state. Then, it is introduced into the internal space of the housing 30 . When the boiler exhaust gas G3 comes into contact with the surface of the pipe 34, the boiler exhaust gas G3 is cooled by the pipe 34, and the fine powder agglomerates on the surface of the pipe 34 and deposits as particulates P as shown in FIG. Specifically, the granular material P adheres to the pipe 34 so as to cover the entire surface of the pipe 34, and particularly grows in a mountain shape on the surface of the pipe 34 toward the upstream side of the boiler exhaust gas G3. At this time, since the gaseous or liquid heavy metal accompanying the boiler exhaust gas G3 and the fine powder is also cooled, the heavy metal changes to a liquid or solid state and is involved in the aggregated fine powder. As described above, the supply source 32 and the pipe 34 function as a cooler CL that cools the boiler exhaust gas G3.

The recovery machine 36 is configured to recover the granular material P adhering to the surface of the pipe 34 . As long as the granular material P can be recovered from the surface of the pipe 34, the recovery method by the recovery device 36 is not particularly limited. For example, the recovery machine 36 may be configured to recover the granular material P by dropping the granular material P from the surface of the pipe 34 . The heavy metal contained in the granular material P is also collected by collecting the granular material P deposited on the surface of the pipe 34 by the collecting machine 36 .

Specific examples of the recovery device 36 include a blower configured to blow gas onto the surface of the pipe 34, a vibrator configured to apply vibration to the pipe 34, and the like. Examples of blowers include suit blowers. Examples of the vibrator include a hammering device that directly hits the pipe 34 and a high-frequency vibration generator that directly or indirectly applies high-frequency vibration to the pipe 34 .

The dust collector 26 is configured to separate the granular material (powder or particles) contained in the pulverizer exhaust gas G5 from the gas. The dust collector 26 is, for example, an electric dust collector. After passing through the dust collector 26, the gas is discharged to the outside of the clinker manufacturing apparatus 1 as exhaust gas G8 of the clinker manufacturing apparatus 1.

The fermenter 28 is configured to ferment organic sludge OM1 introduced from the raw material storage site 10 (for example, sewage sludge, night soil sludge, wastewater sludge, animal manure, etc.). By drying the organic sludge OM1 using the heat of fermentation in the fermentation machine 28, dried sludge OM2 is produced, and sludge properties (for example, volume reduction, sludge handling performance, etc.) are improved. The fermentation temperature in the fermenter 28 can generally be set between 60°C and 80°C.

The fluid F after heat exchange with the boiler exhaust gas G3 in the internal space of the housing 30 is introduced into the fermenter 28 . The heat of the fluid F is used to ferment the organic sludge OM1 in the fermenter 28 . Dried sludge OM2 produced in fermenter 28 is introduced into SP18 and used as part of the heat source for preheating granular raw material M3. In this way, by using the dried sludge OM2 for other purposes, it is possible to effectively utilize the waste and to save energy by reducing the amount of fuel used in SP18.

[Action]
By the way, as shown in FIG. 5, as a result of intensive research by the present inventors, the lower the temperature of the boiler exhaust gas G3 when exchanging heat with the fluid F flowing through the pipe 34, the more powder deposited on the surface of the pipe 34. A new finding was obtained that the mercury concentration in the granules P was increased. In particular, when the temperature of the boiler exhaust gas G3 was 300°C or less, the mercury concentration of the particulate matter P was twice or more as much as when the temperature of the boiler exhaust gas G3 exceeded 300°C. Furthermore, when the temperature of the boiler exhaust gas G3 was 210°C or less, the mercury concentration in the particulate matter P was four times or more as compared to when the temperature of the boiler exhaust gas G3 exceeded 210°C.

In view of the above knowledge, the clinker manufacturing apparatus 1 according to the present embodiment cools the boiler exhaust gas G3 using the pipe 34 through which the fluid F flows, and collects the particulate material P deposited on the surface of the pipe 34 by the collector 36. is configured to Therefore, the heavy metal contained in the granular material P is recovered together with the granular material P by the recovery machine 36 . Therefore, according to the clinker production apparatus 1 according to the present embodiment, heavy metals can be recovered without using an adsorbent, and the amount of heavy metals discharged can be stably suppressed to a low level.

In this embodiment, the kiln exhaust gas G1 from the rotary kiln 20 is used to preheat the granular raw material M3 in SP18. SP exhaust gas G2 generally has a temperature of about 400° C., which tends to be higher than the boiling point or melting point of heavy metals. Therefore, heavy metals are recovered from the gas generated inside the cement kiln 2 on the surface of the pipe 34 while using the heat of the kiln exhaust gas G1 for preheating the granular raw material M3. Therefore, it is possible to achieve both effective use of thermal energy and recovery of heavy metals.

In this embodiment, steam is generated in the boiler 22 using the SP exhaust gas G2 from the SP18. Boiler exhaust gas G3 generally has a temperature of about 300° C. or less, which tends to be higher than the boiling point or melting point of heavy metals. Therefore, heavy metals are recovered from the gas generated inside the cement kiln 2 on the surface of the pipe 34 while using the heat of the SP exhaust gas G2 to generate steam. Therefore, it is possible to achieve both effective use of thermal energy and recovery of heavy metals.

In this embodiment, the pipe 34 through which the fluid F flows functions as a cooler for cooling the boiler exhaust gas G3. Therefore, it is possible to configure the cooler extremely simply.

In this embodiment, the downstream end of pipe 34 is connected to fermentation machine 28 . Therefore, the heat recovered by the fluid F from the boiler exhaust gas G3 can be utilized for the fermentation of the organic sludge in the fermenter .

In this embodiment, the recovery machine 36 can be configured to recover the granular material P by dropping the granular material P from the surface of the pipe 34 . In this case, the heavy metal can be easily recovered together with the particulate material P.

In this embodiment, the dust box exhaust gas G6 from the dust box 24 is used for drying the cement raw material M1 in the dryer 12 . Therefore, it becomes possible to effectively utilize the thermal energy of the dust box exhaust gas G6 in the dryer 12 .

[Other embodiments]
Although the embodiments according to the present disclosure have been described in detail above, various modifications may be made to the above embodiments within the scope of the gist of the present invention.

(1) For example, as shown in FIG. 6, the clinker manufacturing apparatus 1 may further include a damper 38 (breathing means). A damper 38 is arranged between the boiler 22 and the dust box 24 . The damper 38 is configured to be able to adjust the extraction amount of the boiler exhaust gas G3 from the boiler 22 . Therefore, depending on the opening of the damper 38, part or all of the boiler exhaust gas G3 is introduced into the dust box 24, while the remainder of the boiler exhaust gas G3 joins the dust box exhaust gases G4 and G6 without passing through the dust box 24.

According to the example of the clinker manufacturing apparatus 1 shown in FIG. 6, the amount of gas to be cooled in the pipe 34 is restricted by the damper 38, so there is no need to increase the cooling capacity of the pipe 34 more than necessary. Therefore, it is possible to suppress the construction cost of the clinker manufacturing apparatus 1 while stably suppressing the emission of heavy metals to a low level.

(2) As shown in FIG. 7, the dust box 24 may include a plurality of (three in FIG. 7) housings 30A-30C and valves 40A-40C and 42A-42C. Although not shown, pipes 34 through which the fluid F flows are housed inside the housings 30A to 30C. In this case, independent pipes 34 may be accommodated in the housings 30A to 30C, respectively, or one pipe 34 may cross the housings 30A to 30C.

The valves 40A-40C are located upstream of the corresponding housings 30A-30C, respectively. The boiler exhaust gas G3 branched into a plurality (three branches in FIG. 7) can be introduced into the corresponding housings 30A to 30C according to the opening and closing of the valves 40A to 40C. Valves 42A-42C are located downstream of corresponding enclosures 30A-30C, respectively. Exhaust gases discharged from the housings 30A to 30C can go downstream as dust box exhaust gases G4 and G6 according to the opening and closing of the valves 42A to 42C.

In the example of the clinker manufacturing apparatus 1 shown in FIG. 7, for example, when recovering the granular material P in the housing 30A, the valves 40A and 42A are closed to stop the gas flow in the housing 30A, The valves 40B, 40C, 42B and 42C may be opened to allow gas to flow through the housings 30B and 30C. In this case, it is possible to collect the particulate material P in the housing 30A and cool the gas by the piping 34 in the housings 30B and 30C at the same time. Moreover, since the valves 40A and 42A are closed when the granular material P is collected in the housing 30A, scattering of the granular material P containing heavy metals to the outside of the housing 30A can be prevented. It becomes possible.

(3) Heat exchange with the fluid F flowing through the pipe 34 may be performed with the kiln exhaust gas G1, with the SP exhaust gas G2, or with the boiler exhaust gas G3. may be performed in

(4) The downstream end of the pipe 34 may be connected to equipment other than the SP18. For example, the downstream end of the pipe 34 may be connected to the cement kiln 2, the dryer 12, the crusher 14, the rotary kiln 20, the boiler 22, the fermenter 28, the calciner of NSP, and the like. In this case, the heat recovered by the fluid F from the gas generated inside the cement kiln 2 can be effectively used in other equipment.

(5) In order to cool the gas generated inside the cement kiln 2, not only the piping 34 through which the fluid F flows but also various coolers can be used. For example, a Peltier element configured to transfer heat to and from the gas generated inside the cement kiln 2 may be used as a cooler.

(6) The temperature difference between the surface temperature of the pipe 34 through which the fluid F flows and the temperature of the boiler exhaust gas G3 may be, for example, 50°C or higher, and more preferably 150°C or higher. The greater the temperature difference, the higher the heavy metal recovery efficiency tends to be.

DESCRIPTION OF SYMBOLS 1... Clinker manufacturing apparatus (exhaust gas processing apparatus), 2... Cement baking furnace, 12... Dryer (dryer), 14... Pulverizer (dryer), 18... SP (preheater; cement baking furnace), 20... Rotary kiln (Cement firing furnace), 22... Boiler, 24... Dust box, 28... Fermenter, 30, 30A to 30C... Case, 32... Supply source (cooler), 34... Piping (cooler), 36... Recovery machine ( recovery means), 38... damper (bleeding means), CL... cooler, F... fluid, G1... kiln exhaust gas (gas), G2... SP exhaust gas (preheater exhaust gas; gas), G3... boiler exhaust gas (gas), G5 Pulverizer exhaust gas (dryer exhaust gas), G7 Dryer exhaust gas (dryer exhaust gas), M1 Cement raw material, M5 Cement clinker, P Granules.

Claims (13)

a rotary kiln configured to calcine cement raw materials to produce cement clinker;
a preheater configured to preheat the cement raw material using kiln exhaust gas discharged from the rotary kiln;
a boiler configured to generate steam using the preheater exhaust gas discharged from the preheater;
a cooler configured to cool the boiler exhaust gas by exchanging heat between the boiler exhaust gas discharged from the boiler and a working fluid;
a recovery means configured to recover the heavy metals in the boiler exhaust gas and the powder particles adhering to the surface of the cooler as the boiler exhaust gas is cooled by the cooler;
the heavy metal is mercury or a mercury compound ;
The exhaust gas treatment apparatus, wherein the temperature of the boiler exhaust gas introduced into the cooler is 300° C. or less . The apparatus according to claim 1 , wherein the temperature of said boiler exhaust gas introduced into said cooler is 210°C or less. 3. Apparatus according to claim 1 or 2 , wherein the chiller exhaust gas discharged from the chiller has a temperature of 100[deg.]C or higher. The apparatus according to any one of claims 1 to 3 , wherein the cooler is a pipe configured so that cooling fluid can flow. 5. Apparatus according to claim 4 , wherein the fluid is air or water. 6. Apparatus according to claim 4 or 5 , wherein the pipe connects the chiller and other installations located downstream of the chiller. further comprising a fermenter configured to ferment the organic sludge,
The pipe connects the cooler and the fermenter, and is configured to introduce the fluid in the pipe heated by heat exchange with the boiler exhaust gas into the fermenter. 7. Apparatus according to Item 6 . The apparatus according to any one of Claims 1 to 7 , wherein the recovery means is configured to drop the granular material adhering to the surface of the cooler from the surface of the cooler. 9. Any one of claims 1 to 8 , wherein the recovery means is a blower configured to blow gas onto the surface of the cooler, or a vibrator configured to apply vibration to the cooler. 3. Apparatus according to paragraph. Apparatus according to any one of the preceding claims, further comprising a dryer configured to dry the cement raw material using chiller exhaust gas discharged from the chiller. Apparatus according to any one of the preceding claims, further comprising bleed means arranged to partially introduce said boiler exhaust gas into said cooler. Further comprising a first and a second housing including an internal space for housing the cooler,
The apparatus according to any one of claims 1 to 11 , wherein said first and second housings are configured such that said boiler exhaust gas is branched and introduced into each of said internal spaces. The apparatus according to any one of claims 1 to 12 , further comprising a grinder configured to dry and grind the cement raw material using cooler exhaust gas discharged from the cooler.

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