JP2018095913A - Mercury recovery device and mercury recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an amount of mercury discharged into ambient air by efficiently recovering mercury contained in gas.SOLUTION: A mercury recovery device 100 that recovers mercury from a gas flowing in a flow path 1 from an upstream to a downstream includes :a raw material recovery vessel 12 for recovering a solid raw material from a mixed gas containing mercury-containing gas and an unburned portion; an extraction part 13 for extracting mercury-containing gas flowing the flow path P1 on a downstream of the raw material recovery vessel 12; a mercury recovery part 10 for recovering a mercury adsorbent that has absorbed mercury contained in mercury-containing gas by mixing the mercury-containing gas extracted at the extraction part 13 and the mercury adsorbent; a dust collector 15 for collecting raw material dust containing mercury in the mercury-containing gas flowing the flow path P1 at a temperature lower than the mixed gas on the downstream of the extraction part 13; and a flow path P5 for converging the raw material dust and the gas flowing the flow path P1 on the upstream side of the raw material recovery vessel 12.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a mercury recovery apparatus and a mercury recovery method.

  In cement clinker production, since the clinker is produced by heating the raw material to about 1450 ° C., mercury is hardly taken into the clinker. For this reason, there is a concern that when the concentration of mercury contained in raw fuel increases, the amount of mercury released to the atmosphere increases. In recent years, there is a concern that mercury in wastes used as raw materials for cement increases and mercury derived from wastes increases. Therefore, a technique for recovering mercury from exhaust gas is being studied in order to reduce mercury released into the atmosphere during cement clinker production.

Most of the mercury in the exhaust gas exists in the form of metal Hg or HgCl ₂ . In the case of metal Hg, the saturated vapor pressure of mercury is about 2 mg / m ³ N at 0 ° C. and about 3 g / m ³ N at 100 ° C., and the saturated vapor pressure of HgCl ₂ is at the same level. On the other hand, the mercury regulation imposed on the exhaust gas from the plant is usually about 50 μg / m ³ N, which is orders of magnitude lower than the saturated vapor pressures of metals Hg and HgCl ₂ . For this reason, a method such as adsorption or water washing is used to remove mercury from the exhaust gas.

  For example, Patent Document 1 describes a method of introducing dust collected from exhaust gas into a clinker pulverization step as a method of reducing volatile heavy metals such as mercury released into the atmosphere during cement production.

  In Patent Document 2, in a cement manufacturing facility, a part of an exhaust gas of 350 ° C. or higher discharged from a pre-heater which is usually called a suspension pre-heater is extracted, and after separating dust, cooled to 100 ° C. or lower. A method of condensing and removing harmful substances such as mercury has been proposed.

JP 2002-284550 A JP 2005-097005 A

  When removing a substance from a gas by physical adsorption as well as mercury, the substance to be adsorbed in the gas is usually recovered in a temperature range lower than the boiling point of the substance. Generally, the lower the temperature to be recovered, the higher the efficiency because the amount of adsorption increases. In patent document 1, the dust contained in exhaust gas is made to function as an adsorbent. And the dust which adsorb | sucked heavy metals, such as mercury, is collected when the temperature becomes the lowest before releasing exhaust gas to the atmosphere, and heavy metals, such as mercury, are collect | recovered. However, with such a method, the amount of dust to be collected increases and the load of dust processing increases.

  Moreover, when such dust containing mercury is introduced as a raw material into a high-temperature part of a cement clinker production apparatus, the mercury evaporates and the mercury concentration in the exhaust gas increases. This exhaust gas contains dust that is not collected on the cement clinker side. For this reason, the evaporated mercury is adsorbed by the dust again when the temperature decreases. If this dust is used as a raw material and re-introduced into the cement clinker production apparatus, mercury is circulated and accumulated in the cement clinker production apparatus.

  In patent document 2, in order to reduce the mercury etc. accumulated in this way, a part of the exhaust gas at 350 ° C. or higher is extracted. The extracted exhaust gas is cooled to 100 ° C. or lower to condense a vaporized material such as mercury. However, if the exhaust gas is cooled to 100 ° C. or less, countermeasures for dew condensation are required, and the equipment is also enlarged. For this reason, there is a concern that the recovery cost of mercury will increase.

  Accordingly, an object of one aspect of the present invention is to provide a mercury recovery apparatus capable of efficiently recovering mercury in a gas and reducing the amount of mercury released into the atmosphere. Another object of the present invention is to provide a mercury recovery method capable of efficiently recovering mercury in gas and reducing the amount of mercury released into the atmosphere.

  In the present invention, a mercury recovery device that recovers mercury from a gas flowing from upstream to downstream in a flow path, wherein the solid raw material is obtained from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned components. A mercury-containing gas obtained by mixing a raw material recovery device to be recovered, an extraction portion for extracting a mercury-containing gas flowing through a flow channel downstream of the raw material recovery device, and a mercury-containing gas extracted from the extraction portion and a mercury adsorbent A mercury recovery part that recovers the mercury adsorbent that adsorbs the mercury contained in the gas, and the material dust containing mercury in the mercury-containing gas that flows through the flow path at a lower temperature than the mixed gas downstream of the extraction part A mercury recovery device is provided that includes a dust collector that collects the raw material dust, and a flow path that joins the raw material dust to a gas that flows through the flow path on the upstream side of the raw material recovery device.

  The mercury recovery device recovers a solid raw material from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned matter by a raw material recovery device. Since the mixed gas contains mercury evaporated from the solid material, the solid material can be recovered while removing the gaseous mercury. For this reason, the mercury concentration in the solid raw material can be reduced. And the mercury containing gas is extracted in the extraction part downstream of a raw material collection | recovery device. In this mercury-containing gas, mercury contained in the mercury-containing gas and the solid raw material is concentrated. Therefore, the mercury can be efficiently recovered by mixing the extracted mercury-containing gas and the mercury adsorbent in the mercury recovery unit and adsorbing the mercury contained in the mercury-containing gas. In addition, the amount of mercury-containing gas to be extracted can be reduced.

  On the other hand, the mercury-containing gas that is not extracted by the extraction unit contains raw material dust that is not recovered by the raw material recovery unit and includes a solid material that is not extracted by the extraction unit. Since the raw material dust contains a large amount of unburned matter and fine powder excellent in mercury adsorption performance, the raw material dust containing mercury is collected in a dust collector disposed downstream of the extraction part. Here, since the temperature of the mercury-containing gas is lower than the temperature of the mixed gas introduced into the raw material recovery section, the mercury adsorption performance of the raw material dust can be improved and the release of mercury into the atmosphere can be suppressed. The collected raw material dust is joined to the gas flowing through the flow path on the upstream side of the raw material collector. This raw material dust is mixed with a gas at a temperature higher than that of the mercury-containing gas introduced into the dust collector, and then the mercury evaporates and is supplied to the raw material collector as a mixed gas containing the mercury-containing gas and the solid raw material. Is done. In this way, while collecting mercury in a dust collector and collecting it as raw material dust, mercury in a mercury-containing gas enriched with mercury is adsorbed by the mercury adsorbing material in the mercury recovery section. Therefore, the mercury contained in the gas can be efficiently recovered, and the amount of mercury released as gas from the dust collector can be reduced.

  It is preferable that the mercury recovery apparatus includes a merging portion that joins a solid material containing unburned matter with a mercury-containing gas flowing through the flow channel between the extraction portion and the dust collector. Since the unburned matter has excellent mercury adsorption performance, mercury can be adsorbed to the solid material upstream of the dust collector. Therefore, the recovery of mercury is facilitated, and the mercury released as gas from the dust collector can be reduced.

  The mercury recovery apparatus preferably includes a removal unit that removes solids from the extracted mercury-containing gas between the extraction unit and the mercury recovery unit. Thereby, the solid content flowing into the mercury recovery apparatus is reduced, and the recovery load of the mercury adsorbent can be reduced. In the removal part, it is preferable to maintain the temperature of the mercury-containing gas at 200 ° C. or higher. Thereby, mercury contained in the dust removed in the removal unit is reduced, and a mercury-containing gas containing a high concentration of mercury can be processed in the mercury recovery unit. Therefore, mercury can be efficiently recovered while reducing the recovery load of the mercury adsorbent.

  The mercury recovery device preferably includes a circulation flow path that joins at least a part of the mercury adsorbent recovered by the mercury recovery section to the mercury-containing gas. Thus, by circulating and repeatedly using the mercury adsorbing material, the amount of the mercury adsorbing material recovered by effectively using the mercury adsorbing material can be reduced.

  The mercury recovery device preferably includes a flow path for returning a gas obtained by reducing mercury from the mercury-containing gas to a flow path downstream of the extraction section in the mercury recovery section. As a result, the amount of mercury released to the atmosphere can be further suppressed.

  In the mercury recovery apparatus, the dust collector preferably collects raw material dust containing mercury in a mercury-containing gas having a temperature of 300 ° C. or lower. Thereby, the mercury gas of the mercury-containing gas is condensed and efficiently adsorbed to the raw material dust. Since the amount of mercury adsorbed by the raw material dust increases, the amount of mercury released to the atmosphere can be further reduced.

  The raw material recovery device in the mercury recovery device is a cyclone with a kiln with a suspension preheater for producing cement clinker, and a charging device for supplying a solid raw material to the inlet side of the cyclone, and an exhaust gas that is a mercury-containing gas is extracted to the outlet side of the cyclone. And a bleed portion to be provided. By using the mercury recovery device as a cyclone in a kiln with a suspension preheater for manufacturing cement clinker in this way, the amount of mercury released into the atmosphere at the cement clinker manufacturing facility can be efficiently reduced.

  In the present invention, the solid raw material collected by the dust collector preferably contains at least one of coal ash and incineration ash. Since coal ash and incineration ash contain unburned components, they have excellent mercury adsorption performance. Therefore, the amount of mercury released to the atmosphere can be sufficiently reduced.

  In another aspect, the present invention provides a mercury recovery method for recovering mercury from a gas flowing in a flow path from upstream to downstream, from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned components. A raw material recovery step for recovering a solid raw material with a raw material recovery device; a bleeding step for extracting a part of the mercury-containing gas flowing through the flow path obtained by recovering the solid raw material in the extraction portion; and a mercury-containing gas extracted Mercury recovery process for mixing mercury adsorbent and recovering the mercury adsorbent that adsorbs mercury contained in the mercury-containing gas, and mercury circulating in the flow path at a lower temperature than the mixed gas downstream of the extraction part A mercury recovery method comprising: a dust collection step of collecting raw material dust adsorbing mercury in the contained gas; and a merging step of combining the raw material dust with the gas flowing through the flow path on the upstream side of the raw material collector. Provide .

  According to the said mercury recovery method, it has the raw material recovery process which collect | recovers a solid raw material with a raw material recovery device from the mixed gas containing a mercury containing gas and the solid raw material containing an unburned part. In the raw material recovery step, the solid raw material can be recovered while removing the gaseous mercury by obtaining the solid raw material from the mixed gas containing mercury evaporated from the solid raw material. For this reason, the mercury concentration in the solid raw material can be reduced. And in the extraction process, the mercury containing gas which distribute | circulates the flow path obtained by collect | recovering solid raw materials is extracted. In this mercury-containing gas, mercury contained in the solid raw material and the mercury-containing gas is concentrated. Therefore, in the mercury recovery step, mercury can be efficiently recovered by mixing the extracted mercury-containing gas and the mercury adsorbent and adsorbing mercury contained in the mercury-containing gas. Further, the amount of mercury-containing gas extracted in the extraction process can also be reduced.

  On the other hand, the mercury-containing gas that is not extracted in the extraction process contains raw material dust that contains a solid material that is not recovered in the raw material recovery process and that is not extracted in the extraction part. Since the raw material dust contains a large amount of unburned matter and fine powder excellent in mercury adsorption performance, the raw material dust containing mercury is collected in the dust collection process. Here, since the temperature of the mercury-containing gas is lower than the temperature of the mixed gas introduced into the raw material recovery section, the mercury adsorption performance of the raw material dust can be improved and the release of mercury into the atmosphere can be suppressed. The collected raw material dust is joined to the gas flowing through the flow path on the upstream side of the raw material collector. When this raw material dust is combined with a gas having a temperature higher than that of the mercury-containing gas that is processed in the dust collection process, the mercury evaporates and becomes a mixed gas containing the mercury-containing gas and the solid raw material. Supplied. In this way, mercury in the mercury-containing gas, which is concentrated in the mercury recovery unit, is removed from the mercury-containing gas by collecting and collecting the mercury in the dust in the dust collection process. Adsorbed and recovered with Therefore, mercury contained in the gas can be efficiently recovered, and the amount of mercury released as gas through the dust collection process can be reduced.

  In the dust collection step, it is preferable to collect raw material dust containing mercury in a mercury-containing gas at 300 ° C. or lower. Thereby, the mercury gas of the mercury-containing gas is condensed and efficiently adsorbed to the raw material dust. Since the amount of mercury adsorbed by the raw material dust increases, mercury released to the atmosphere can be further reduced.

  In one aspect, the present invention can provide a mercury recovery apparatus that can efficiently recover mercury contained in a gas and reduce the amount of mercury released into the atmosphere. In another aspect, the present invention can provide a mercury recovery method capable of efficiently recovering mercury contained in a gas and reducing the amount of mercury released into the atmosphere.

FIG. 1 is a diagram showing an embodiment of a mercury recovery apparatus. FIG. 2 is a diagram showing another embodiment of the mercury recovery apparatus. FIG. 3 is a view showing still another embodiment of the mercury recovery apparatus. FIG. 4 is a view showing still another embodiment of the mercury recovery apparatus. FIG. 5 is a diagram showing a cement clinker production facility equipped with a mercury recovery device.

  Hereinafter, an embodiment of a mercury recovery apparatus of the present invention will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted in some cases. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a diagram showing an embodiment of a mercury recovery apparatus. The mercury recovery apparatus 100 in FIG. 1 is an apparatus that recovers mercury from the gas flowing through the flow path P1. The flow path P1 includes various devices and piping that connects them. The gas in the flow path P1 flows from the left to the right in FIG. For this reason, the left side in FIG. 1 corresponds to the upstream side in the flow direction of the gas flowing through the flow path P1, and the right side in FIG. 1 corresponds to the downstream side in the flow direction of the gas flowing through the flow path P1. In the mercury recovery device 100, the merging portion 11, the raw material recovery device 12, the bleed portion 13, the merging portion 17 and the dust collector 15 are arranged in series in this order from the upstream side along the flow direction of the mercury-containing gas in the flow path P1. Has been placed. The merging portion 11, the raw material recovery device 12, the bleed portion 13, the merging portion 17, and the dust collector 15 are communicated with each other through the flow path P1.

A raw material charging machine 14 is connected to the merging portion 17 through the flow path P4 so that the solid raw material merges with the mercury-containing gas flowing in the flow path P1. Examples of the raw material charging machine 14 include those capable of adjusting the supply amount of the solid raw material. For example, a rotary feeder capable of adjusting the number of rotations may be used. The raw material feeder 14 supplies an appropriate amount of solid raw material and joins the mercury-containing gas. As the solid raw material, a solid material containing unburned components can be used, and examples thereof include coal ash and incinerated ash. It should be noted that some chloride may be added together with the mercury adsorbent as long as the chloride that changes the metal Hg to HgCl ₂ is insufficient depending on the properties of the exhaust gas and the solid raw material.

The solid raw material may contain dust obtained by collecting a mercury adsorbing material such as activated carbon into a mercury-containing gas and then collecting the material. Since the solid raw material contains unburned components such as unburned carbon, the mercury contained in the mercury-containing gas can be sufficiently adsorbed. Therefore, the amount of mercury released to the atmosphere can be sufficiently reduced. The mercury concentration in the exhaust gas discharged from the dust collector 15 through the flow path P9 may be, for example, 50 μg / m ³ N or less, or 30 μg / m ³ N or less.

  After the solid raw material is merged with the mercury-containing gas at the merging portion 17, the mercury-containing gas containing the solid raw material is introduced into the dust collector 15 (dust collection step). The dust collector 15 may be, for example, an electric dust collector or a bag filter. The temperature of the mercury-containing gas introduced into the dust collector 15 is lower than that of the mixed gas introduced into the raw material collector 12 from the viewpoint of improving the mercury adsorption performance of the solid raw material, for example, 50 to 300 ° C. When the dust collector 15 is an electric dust collector, the temperature of the mixed gas introduced into the dust collector 15 is preferably 90 to 120 ° C. from the viewpoint of dust collection efficiency and mercury removal efficiency. it can. The temperature of the mercury-containing gas can be reduced, for example, by watering or the like on the upstream side of the dust collector 15. When the dust collector 15 is a bag filter, it can be operated even when the temperature of the mixed gas is 50 to 300 ° C. by selecting an appropriate material. The lower the temperature of the mixed gas, the higher the efficiency of physical adsorption, but it is preferably 100 to 180 ° C. from the viewpoints of dew condensation countermeasures, chimney effects and material costs.

  When the dust collector 15 is a bag filter, the contact time between the mercury-containing gas and the solid material can be extended. When the dust collector 15 is an electric dust collector, by increasing the amount of solid raw material including unburned components supplied from the raw material input device 14 as compared with the case of the bag filter, Mercury emissions can be suppressed.

  In order to reduce the load on the dust collector 15, dust collection equipment such as a cyclone and a gravity settling chamber may be provided on the upstream side of the dust collector 15. The dust collection facility includes a device that collects dust by changing the flow of exhaust gas after watering and using gravity, such as a humidity control tower.

  In the dust collector 15, raw material dust containing a solid raw material including unburned components is collected. This raw material dust contains mercury adsorbed by the unburned component in addition to the unburned component. The dust collector 15 is connected to a flow path P5 that joins the collected raw material dust to the gas flowing through the flow path P1 in the merging section 11 on the upstream side of the raw material collector 12. The raw material dust collected by the dust collector 15 flows through the flow path P5 and joins the gas flowing through the flow path P1 at the merging portion 11. At this time, it joins so that the temperature of the mercury containing gas obtained by joining may become higher than the temperature of the mixed gas introduce | transduced into the dust collector 15 (merging process).

  At least a part of the raw material dust collected by the dust collector 15 may be extracted by the flow path P10 and used for other purposes. On the other hand, all of the raw material dust collected by the dust collector 15 may be merged with the gas at the merge section 11. In this case, the flow path P10 may be omitted.

  An introduction machine may be provided in the flow path P5, and raw material dust may be supplied from the introduction machine to the merging section 11. As the charging machine, an apparatus for supplying a solid content such as powder can be used. From the viewpoint of airtightness, a rotary feeder is preferable.

The boiling point of mercury is 357 ° C. for metal Hg and 304 ° C. for HgCl ₂ . Therefore, the temperature of the mercury-containing gas is preferably 400 ° C. or higher, and may be 400 to 800 ° C., for example. In this case, the raw material dust that joins the gas at the junction 11 is heated to about 300 to 400 ° C. For this reason, most of the mercury contained in the raw material dust evaporates. As a result, a high-concentration mercury-containing gas flows through the flow path P1.

  The gas that merges with the raw material dust in the merging section 11 may be, for example, exhaust gas of a cement clinker manufacturing apparatus, or may be combustion gas of a furnace that uses a gas burner. Moreover, the exhaust gas which burned coal, and the mercury containing gas which heated the raw material containing mercury may be sufficient. When the gas contains mercury and unburned matter or dust, the mercury and dust contained in the gas can be removed at the same time.

  The mercury-containing gas obtained at the junction 11 is introduced into the raw material recovery unit 12 (raw material recovery step). The dust collection efficiency of the raw material collector 12 is preferably 80% or more. In order to reduce the amount of mercury adsorbed on the recovered raw material and increase the amount of mercury recovered in the mercury recovery unit 10, mixing in the raw material recovery unit 12 until it is introduced from the merging unit 11 to the raw material recovery unit 12 The higher the gas temperature is, for example, preferably 300 ° C. or higher. This makes it possible to evaporate the mercury and lower the mercury adsorption performance of the unburned portion, thereby reducing the mercury concentration in the solid raw material recovered by the raw material recovery device 12.

  Since the raw material recovery device 12 is provided in the flow path P1, it is preferable to have a low pressure loss. Further, in order to keep the temperature of the mercury-containing gas high in the raw material recovery device 12, it is preferable that the residence time of the mercury-containing gas is short and the mercury-containing gas is hardly cooled. From such a viewpoint, it is preferable that the raw material collector 12 is, for example, a cyclone or an inertia dust collector.

  The solid raw material that could not be recovered by the raw material recovery device 12 generally has many small-diameter particles containing a large amount of unburned matter, and has the same mercury adsorption action as the solid raw material containing the unburned amount supplied from the raw material feeder 14. For this reason, it is preferable to reduce the low pressure loss of the raw material recovery unit 12 and to allow some small diameter particles to escape with a dust collection efficiency of 90 to 98%. Note that a bag filter or an electrostatic precipitator with high dust collection efficiency may be used depending on the operating conditions.

  The mercury-containing gas obtained by recovering the raw material in the raw material recovery device 12 also includes mercury derived from the solid raw material, so that the mercury concentration is high. This mercury-containing gas may contain small-diameter raw material dust containing a large amount of unburned matter that could not be recovered by the raw material recovery device 12. Such mercury-containing gas flows through the flow path P <b> 1 and reaches the extraction unit 13 on the downstream side of the raw material recovery unit 12. In the extraction part 13, the extraction pipe P3 is connected to the flow path P1. The extraction unit 13 extracts a part of the mercury-containing gas that has circulated through the flow path P1 (extraction process).

  The extraction pipe P3 is provided in the extraction unit 13 so as to branch from the flow path P1. The extraction pipe P3 may be connected to form an acute angle with respect to the flow direction of the mercury-containing gas in the flow path P1. Thereby, low pressure loss can be achieved. Conversely, the extraction pipe P3 may be connected so as to form an obtuse angle with respect to the flow direction of the mercury-containing gas in the flow path P1. Thereby, the suction amount of dust contained in the mercury-containing gas can be reduced. Such a form is particularly preferable when a device for removing the solid content is not provided between the extraction unit 13 and the mixing of the mercury adsorbent. The extraction unit 13 is disposed between the raw material collector 12 and the merging unit 17. The extraction pipe P3 may be a normal pipe, and a refractory may be applied depending on the temperature.

  In the extraction part 13, the flow path P1 may have a bent part or a curved part. In this case, if the extraction part 13 is configured by connecting the extraction pipe P3 to the inner peripheral side of the bent part or the curved part of the flow path P1, the amount of dust of the mercury-containing gas extracted can be reduced. Thereby, the amount of dust collected by the mercury collecting dust collector 10B can be reduced.

  The extraction rate refers to a ratio of extracting the mercury-containing gas flowing through the flow path P1 by the extraction unit 13. The required extraction rate is the ratio of the amount of mercury recovered when mercury is collected by the mercury recovery device 100 to the amount of mercury released to the atmosphere when the mercury recovery device 100 does not collect mercury. It can be generally calculated from the recovery rate (assumed as A) and the concentration rate (assumed as B). Here, the concentration ratio is the extraction unit 13 with respect to the amount of mercury released into the atmosphere when mercury is not recovered by the mercury recovery device 100 (for example, the amount per hour expressed in units such as g / day). Is the magnification of the amount that represents the amount of mercury flowing in the flow path P1 immediately before bleed in the same unit. When A is about 80% or less, the concentration rate does not change so much, so the necessary extraction rate can be calculated by multiplying A / B by about twice the safety factor. In the present embodiment, B can be 100 times or more. If A is 50%, from the above calculation (50% / 100 × 2 = 1%), an extraction rate of 1% or less is sufficient.

  The mercury-containing gas that circulates through the extraction pipe P3 is introduced into the mercury recovery unit 10 to remove mercury (mercury recovery process). The mercury recovery unit 10 supplies a mercury adsorbent to the extraction pipe P3, mixes the mercury adsorbent with the mercury-containing gas, and mercury that collects the mercury adsorbent that adsorbs the mercury contained in the mercury-containing gas. And a dust collecting device 10B. As the charging machine 10A, a general powder supply apparatus can be used. From the viewpoint of airtightness, the charging machine 10A preferably has a rotary feeder, and preferably has a table feeder in order to improve the measurement accuracy of the mercury adsorbent to be charged.

  Similarly to the dust collector 15, the mercury collecting dust collector 10 </ b> B may be an electric dust collector or a bag filter. From the viewpoint of mercury adsorption efficiency on the mercury adsorbent, the mercury collecting dust collector 10B is preferably a bag filter. The mercury dust collector 10B may be a cyclone.

As the mercury adsorbent, a general material having a large specific surface area and excellent physical adsorption performance can be used. For example, dust, fly ash, activated carbon, and zeolite with a large amount of unburned matter are included. Activated carbon or zeolite may be used from the viewpoint of reducing the solid content recovered by the mercury collecting dust collector 10B. The fly ash may contain a chloride such as CaCl ₂ . When chloride is contained, mercury contained in the mercury-containing gas reacts to produce HgCl ₂ . Since HgCl ₂ is more easily adsorbed than metal Hg, the mercury recovery efficiency can be further improved by using fly ash containing chloride. In this case, mercury can be efficiently adsorbed even when the temperature of the mercury-containing gas is 200 ° C. or higher.

  Incineration ash and coal ash taken out by dry process contain a lot of chloride. The unburned matter extracted by pulverizing these can be suitably used as a mercury adsorbent even when the temperature of the mercury-containing gas is 200 ° C. or higher. Activated carbon or zeolite may be modified by passing it through a gas containing chloride. As a result, mercury can be efficiently adsorbed even when the temperature of the mercury-containing gas is 200 ° C. or higher, as in the above-described fly ash. The reforming with the gas containing chloride may be performed on the solid raw material supplied from the raw material feeder 14.

  The gas that has collected the mercury adsorbent by the mercury dust collector 10B can be released to the atmosphere from the flow path P7 if it is appropriately treated. However, the processing gas may be merged with the mercury-containing gas flowing through the flow path P1 so as not to be extracted again. Moreover, it is good to merge with the mercury containing gas which distribute | circulates downstream from the extraction part 13. FIG. In this embodiment, since the mercury-containing gas having a high mercury concentration is extracted, the amount of the mercury-containing gas to be extracted can be reduced. For this reason, even if the exhaust gas from the mercury collection dust collector 10B is merged with the mercury-containing gas flowing through the flow path P1, the processing can be continued stably without greatly increasing the load on each device.

  On the other hand, at least a part of the mercury adsorbent that has adsorbed the mercury collected by the mercury collecting dust collector 10B may be returned to the input device 10A and reused or discharged from the flow path P8. The used mercury adsorbent is treated by a known process. In this way, mercury released into the atmosphere can be reduced. The mercury-containing gas that has not been extracted by the extraction unit 13 is joined by the solid material in the junction unit 17. After the merge, the above-described series of processes is repeated. Thereby, the solid raw material containing mercury can be used continuously.

  FIG. 2 is a diagram showing another embodiment of the mercury recovery apparatus. The mercury recovery apparatus 110 in FIG. 2 is an apparatus that recovers mercury from the gas flowing through the flow path P1 in the same manner as the mercury recovery apparatus 100 in FIG. The gas in the flow path P1 is circulated from the left to the right in FIG. For this reason, the left side in FIG. 2 corresponds to the upstream side in the flow direction of the gas flowing through the flow path P1, and the right side in FIG. 2 corresponds to the downstream side in the flow direction of the gas flowing through the flow path P1.

  The mercury recovery device 110 is provided with (i) a removal device 10D for removing dust in the extraction pipe P3, and (ii) a gas collected from the mercury adsorbent by the mercury collecting dust collector 10B through the flow path P7. (Iii) a part of the dust containing the mercury adsorbent that adsorbs the mercury collected by the mercury collecting dust collector 10B. The mercury collecting apparatus 100 is different from the mercury collecting apparatus 100 in that it is supplied to the charging machine 10C through the flow path P11. Since the other configuration is the same as that of the mercury recovery apparatus 100, a duplicate description is omitted here.

  Examples of the remover 10D include a bag filter and an electric dust collector. Most of the solid content contained in the mercury-containing gas extracted by the extraction pipe P3 is removed by the remover 10D. The remover 10 </ b> D is maintained at 200 ° C. or higher, preferably 300 ° C. or higher, in order to suppress mercury from adsorbing to the solid content to be removed. By providing the remover 10D, it is possible to reduce dust brought into the mercury collecting dust collector 10B accompanying the mercury-containing gas. As a result, the mercury concentration of the mercury adsorbent collected by the mercury collecting dust collector 10B becomes high and it becomes possible to adsorb mercury efficiently, so that the amount of mercury adsorbent can be reduced.

  After the solid content is removed in the remover 10D, the mercury-containing gas is supplied from the charging device 10C to the mercury-containing gas, and the mercury-containing gas and the mercury-adsorbing material are mixed. In the mercury collecting dust container 10B, dust containing a mercury adsorbing material that adsorbs mercury is collected. Part of the collected dust is returned to the input device 10C via the flow path P11 and recycled. On the other hand, the other part of the collected dust flows through the flow path P8 and is discharged. The flow path P11 and the flow path P12 may be, for example, screw conveyors that do not retain heat. Thus, when the dust is cooled in the flow path P11 and the flow path P12 and sent to the extraction pipe P3, the temperature of the mercury-containing gas after being recharged is lowered, so that the adsorption performance of the mercury adsorbent can be improved.

  The amount of dust returned (circulated and used) to the charging machine 10C can be adjusted according to the temperature of the mercury-containing gas and the type of the mercury collecting dust collector 10B. For example, 80% or more of the dust collected by the mercury collecting dust collector 10B may be returned to the input device 10C. The mercury adsorbing material reused in this way may have improved mercury adsorption performance due to contact with the mercury-containing gas. Therefore, the amount of dust discharged from the mercury collection dust collector 10B can be reduced.

  As can be seen from the fact that mercury is used for measurement of pore volume, mercury has a property that it is difficult to wet with a general adsorbent. And it has characteristics different from other substances such as a wide temperature range in liquid and extremely high surface tension, and mercury tends to gather and form droplets easily. Therefore, when an adsorbent with a large adsorption surface area having many elongated pores is used, a mercury droplet is formed at the entrance of the pore to form a lid. For this reason, the adsorption | suction surface of the back of a pore may become difficult to exhibit an original function. The mercury that forms the lid of the droplet also evaporates again if it has temperature and time, and moves to the back of the pores to be adsorbed. As a result, the entire adsorption surface of the mercury adsorbent can be effectively utilized.

  Therefore, if a circulation path for supplying at least a part of the mercury adsorbent collected by the mercury collecting dust collector 10B from the input device 10C is provided again, even if it seems to be almost broken through, a considerable amount of mercury is adsorbed. be able to. Therefore, in the mercury adsorbent that is circulated, the temperature decreases while being recovered by the mercury collecting dust collector 10B and re-supplied from the input device 10C to the extraction pipe P3, and the temperature rises at the time of re-supply, so It is conceivable that mercury easily diffuses into the surface.

  The mercury recovery unit 10 may have a charging machine 10A shown in FIG. 1 in addition to the charging machine 10C. In this case, the input device 10C may be an input device that inputs dust collected by the mercury collecting dust collector 10B, and the input device 10A may be an input device that inputs a fresh mercury recovery material. In this way, it is possible to easily adjust and control the supply amount of the mercury recovery material. As the charging machine 10C, the same one as the charging machine 10A can be used.

  Of the dust collected by the mercury collecting dust collector 10B, only dust having a high mercury concentration may be collected from the flow path P8. For example, in a tank installed at the dust outlet of the mercury collection dust collector 10B, the dust collected by the mercury collection dust collector may be fluidized, and only the dust that has a large amount of unburned floating may be collected and collected. On the other hand, the dust that has not been recovered may be mixed with the mercury-containing gas in the flow path P1 as dust containing unburned matter.

  Mercury collection dust collector 10B may be a bag filter or a cyclone. In the bag filter, since the mercury adsorbent forms a dust layer on the filter surface, the contact between the mercury-containing gas and the mercury adsorbent can be improved. Further, since the residence time can be increased, the adsorption performance of mercury or the like in the mercury recovery unit 10 can be further improved. In the case of using a cyclone, it is preferable that the dust collection efficiency is set to 95% or more, for example, and that the mercury adsorption material is sufficiently recycled to sufficiently increase the mercury adsorption concentration.

  The processing gas from which the dust is separated by the mercury collecting dust collector 10B and reduced in mercury flows through the flow path P7 and returns to the flow path P1, and is combined with the mercury-containing gas that has not been extracted in the extraction section 13 and the merge section 18. Join. As a result, the processing gas released from the mercury dust collector 10B into the atmosphere is reduced, so that the amount of mercury released into the atmosphere can be further reduced. Further, the sensible heat of the processing gas can be effectively used.

  FIG. 3 is a view showing still another embodiment of the mercury recovery apparatus. The mercury recovery apparatus 120 in FIG. 3 is an apparatus that recovers mercury from the gas flowing through the flow path P1 in the same manner as the mercury recovery apparatus 100 in FIG. The gas in the flow path P1 circulates from left to right in FIG. For this reason, the left side in FIG. 3 corresponds to the upstream side in the flow direction of the gas flowing through the flow path P1, and the right side in FIG. 3 corresponds to the downstream side in the flow direction of the gas flowing through the flow path P1.

  The mercury recovery device 120 is different from the mercury recovery device 100 in that it has a junction 17 that joins the solid raw material to the gas flowing through the flow path P1 between the junction 11 and the raw material collector 12. Since the other configuration is the same as that of the mercury recovery apparatus 100, a duplicate description is omitted here. Also in the case of the mercury recovery apparatus 120, after the mercury contained in the solid raw material is separated from the solid raw material in the raw material recovery device 12, the mercury recovery unit 10 processes the mercury-containing gas extracted from the extraction unit 13, Mercury is recovered. Therefore, mercury can be efficiently recovered while suppressing mercury released into the atmosphere. Since the amount of raw material dust contained in the mercury-containing gas extracted from the extraction unit 13 is increased, a remover 10D for removing dust may be provided in the same manner as the mercury recovery apparatus 110 in FIG.

  FIG. 4 is a view showing still another embodiment of the mercury recovery apparatus. The mercury recovery device 130 in FIG. 4 is a device that recovers mercury from the gas flowing through the flow path P1 in the same manner as the mercury recovery device 100 in FIG. The gas in the flow path P1 circulates from left to right in FIG. Therefore, the left side in FIG. 4 corresponds to the upstream side in the flow direction of the gas flowing through the flow path P1, and the right side in FIG. 4 corresponds to the downstream side in the flow direction of the gas flowing through the flow path P1.

  The mercury recovery device 130 is different from the mercury recovery device 100 in that the mercury recovery device 130 has a merging portion 17 for merging the solid raw material with the gas flowing through the flow channel P1 in the flow channel P1 upstream of the merging portion 11. Since the other configuration is the same as that of the mercury recovery apparatus 100, a duplicate description is omitted here. Also in the case of the mercury recovery apparatus 130, after the mercury contained in the solid raw material is separated from the solid raw material in the raw material recovery device 12, the mercury recovery unit 10 processes the mercury-containing gas extracted from the extraction unit 13, Mercury is recovered. Therefore, mercury can be efficiently recovered while suppressing mercury released into the atmosphere. Since the amount of raw material dust contained in the mercury-containing gas extracted from the extraction unit 13 is increased, a remover 10D for removing dust may be provided in the same manner as the mercury recovery apparatus 110 in FIG. Further, the merging portion 17 may be provided on the flow path P5, and the solid raw material may be introduced into the flow path P1 from the merging portion 11 together with the raw material dust collected by the dust collector 15.

  FIG. 5 is a diagram showing a cement clinker production facility equipped with a mercury recovery device. A cement clinker production facility 200 shown in FIG. 5 includes a cement clinker production device 50 and a mercury recovery device 150. The cement clinker manufacturing apparatus 50 includes a kiln 60 and a suspension preheater SP. That is, the cement clinker manufacturing apparatus 50 includes a kiln with a suspension preheater. The uppermost cyclone 12 of the suspension preheater SP corresponds to a raw material recovery unit. The solid line in FIG. 5 indicates the flow of solid, and the broken line indicates the flow of gas and dust accompanying the gas.

  The SP exhaust gas G1 discharged from the uppermost cyclone 12 of the suspension preheater SP of the cement clinker manufacturing apparatus 50 is exhausted through the flow path P1B which is the main flue by the suction of the SP fan 23.

  The SP exhaust gas G1 (mercury-containing gas) discharged from the uppermost cyclone 12 has a high mercury concentration because it accompanies the mercury evaporated in the uppermost cyclone 12 and the like. The SP exhaust gas G1 temperature may have a temperature of 300 to 400 ° C., for example, immediately after being discharged from the uppermost cyclone 12 to the flow path P1B. In some other embodiments, a boiler or a watering device may be provided in the middle of the flow path P1B to cool to about 250 ° C. at the outlet of the SP fan 23.

  The SP exhaust gas G1 circulates in the flow path P1C connected to the outlet of the SP fan 23 and reaches the extraction unit 13. An extraction pipe P3 is connected to the extraction unit 13. Part of the SP exhaust gas G1 is extracted by the extraction pipe P3. The extraction rate of the SP exhaust gas G1 extracted from the flow path P1C, which is the main flue, into the extraction pipe P3 may be, for example, 1% or less. According to the present embodiment, the concentration rate of mercury in the SP exhaust gas becomes 100 times or more, and thus the extraction rate can be lowered.

  In an example of the present embodiment, the temperature of the SP exhaust gas G1 extracted by the extraction unit 13 is set to 250 ° C., coal ash is supplied from the raw material input device 14, and an electric dust collector is used as the dust collector 15 at about 90 ° C. When operating at 1, the concentration rate of mercury in the SP exhaust gas is calculated to be about 200 times.

  By further reducing the amount of mercury released to the atmosphere using a bag filter as the dust collector 15, or by increasing the temperature of the SP exhaust gas G1 extracted by the extraction unit 13 to increase the amount of mercury evaporation If the concentration rate of mercury is further increased, the extraction rate can be further reduced.

  The SP exhaust gas G1 extracted by the extraction pipe P3 is introduced into the remover 10D. The remover 10D may be a bag filter or an electrostatic precipitator, or a combination thereof. Since the remover 10D has the bag filter, the raw material dust can be removed with high accuracy. The remover 10D is not limited to a bag filter and an electric dust collector, and may be, for example, a highly efficient cyclone (multi-clone) having a dust collection efficiency of 99% or more.

  By the remover 10D, most of the raw material dust accompanying the SP exhaust gas G1 can be removed. As a result, the load on the rear stage of the mercury recovery unit 10 can be reduced. The temperature of the SP exhaust gas G1 in the remover 10D is preferably 200 ° C. or higher, and more preferably 300 ° C. or higher. Thereby, it is possible to suppress mercury from adsorbing to the raw material dust captured by the remover 10D. The raw material dust collected by the remover 10D may be joined to the flow path P5B by the flow path P21.

  The mercury adsorbent is supplied from the input device 10A to the SP exhaust gas G1 whose solid content is sufficiently reduced by the remover 10D through the flow path P12A, and the SP exhaust gas G1 that is a mercury-containing gas and the mercury adsorbent are mixed. As a result, mercury contained in the SP exhaust gas G1 is adsorbed by the mercury adsorbent. The mercury adsorbent may be measured and supplied from the charging machine 10A. The mixed gas containing the SP exhaust gas G1 and the mercury adsorbent is introduced into the mercury collecting dust collector 10B. In the mercury collecting dust collector 10B, dust containing a mercury adsorbing material that adsorbs mercury is collected, and exhaust gas having a mercury concentration lower than that of the SP exhaust gas G1 is obtained.

  Part of the dust collected by the mercury collecting dust collector 10B is discharged out of the system from the flow path P8, and the remaining dust is returned to the input machine 10C via the flow path P11. Then, it is mixed again with the SP exhaust gas G1 from the charging device 10C via the flow path P12C. Thus, the flow path P11, the charging machine 10C, and the flow path P12C constitute a circulation flow path for the mercury adsorbent. The amount of mercury adsorbent used can be reduced by circulating and repeatedly using the mercury adsorbent. The dust discharged from the flow path P8 may be subjected to final treatment of mercury by removing mercury by a process not shown.

  As the mercury adsorbent, for example, dust, fly ash, activated carbon, and zeolite with a large amount of unburned content can be used.

  An input device 10C for supplying the dust collected by the mercury collecting dust collector 10B and an input device 10A for supplying a fresh mercury adsorbent are provided separately. While the mercury adsorbing material supplied from the charging device 10A is supplied while being measured, the mercury adsorbing material (circulation utilization) supplied from the charging device 10C may be supplied without being measured. For example, a screw conveyor may be used as the charging machine 10C. At this time, for example, when the operation is performed so that the material seal works, the mercury adsorbent that is circulated can be appropriately cooled.

  Mercury collection dust collector 10B operates, for example at 100-300 ° C. Thereby, the mercury recovery rate of the extracted SP exhaust gas G1 can be sufficiently increased. The mercury recovery rate of the extracted SP exhaust gas G1 can be, for example, 80% or more. When the mercury dust collector 10B is operated at a temperature exceeding 250 ° C., it is preferable to use a high-temperature bag filter. Thereby, the mercury recovery rate of the extracted SP exhaust gas G1 can be maintained at, for example, 50% or more. When the mercury recovery rate is low, the mercury recovery rate can be increased by increasing the extraction rate.

  Of the dust collected by the mercury collection dust collector 10B, the amount of dust discharged out of the system from the flow path P8 is, for balance, dust that is not removed by the remover 10D and the mercury adsorption supplied from the input device 10A. This is the sum of the materials. In such a case, the range where the transportation capacity does not become a bottleneck can be automatically balanced if the ratio of the dust extracted outside the system is kept constant. For example, the ratio is adjusted using a distribution damper at the branch point between the flow path P8 and the flow path P11 so that the mercury concentration in the dust discharged out of the system from the flow path P8 becomes an appropriate target value. May be.

  The exhaust gas with reduced mercury obtained by the mercury collecting dust collector 10 </ b> B flows through the flow path P <b> 7 and returns to the flow path P <b> 1 </ b> C, and merges with the SP exhaust gas G <b> 1 that has not been extracted by the extraction unit 13. The merging portion 18 is provided on the downstream side of the extraction portion 13 with reference to the flow direction of the SP exhaust gas G1 in the flow path P1C. In some other embodiments, the exhaust gas from the mercury dust collector 10B may be discharged into the atmosphere after being separately treated with the exhaust gas without returning to the flow path P1C, or further downstream of the flow path P1C. You may return to the side.

  The SP exhaust gas G1 flowing through the flow path P1B joins with the exhaust gas from the mercury collecting dust collector 10B at the merge section 18, and after flowing through the branch section 26 and the flow path P1D, is introduced into the gas processing section 80. The gas processing unit 80 uses a dry pulverizer 82, a sprinkler 84, and a dryer 86. The dry pulverizer 82 is an apparatus for pulverizing cement raw materials such as limestone, clay, meteorite, and iron concentrate, and the dryer 86 is an apparatus for drying cement raw materials. The watering device 84 is a device that cools the temperature of the exhaust gas by spraying water. The cement raw material pulverized and dried by the dry pulverizer 82 and the dryer 86 is introduced into the raw material silo 20 from the flow path P25 after passing through a flow path (not shown).

  The exhaust gas that has flowed through the flow path P1D is introduced into the drying pulverizer 82, the dryer 86, and the sprinkler 84 and cooled. The exhaust gas that has passed through the dry pulverizer 82 is extracted through the flow path P1E. A flow path P4 for supplying a solid raw material from the raw material charging machine 14 is connected to the junction 17 of the flow path P1E. In this junction part 17, the exhaust gas and solid raw material which distribute | circulate the flow path P1E merge. As the solid raw material, a solid material containing unburned components can be used, and for example, it is preferable to include coal ash and / or incinerated ash. By bringing the solid raw material containing unburned content into the merging portion 17 on the downstream side of the dry pulverizer 82, the contact time between the exhaust gas and the solid raw material can be extended. As a result, the amount of mercury adsorbed by the solid material can be increased, and the efficiency of mercury recovery can be further increased.

  The mixed gas of the exhaust gas and the solid material obtained in the merging portion 17 merges with the exhaust gas discharged from the sprinkler 84 and the dryer 86, and then flows through the flow path P1F and is introduced into the dust collector 15. In the dust collector 15, the mixed gas is separated into raw material dust and exhaust gas. Since the mercury contained in the mixed gas is adsorbed by the solid raw material containing unburned components, the exhaust gas from the dust collector 15 has a sufficiently reduced mercury concentration. For this reason, it discharge | releases to air | atmosphere via the flow path P9.

  The configuration of the gas processing unit 80 is not limited to that described above. For example, in FIG. 5, in the gas processing unit 80, the drying pulverizer 82, the watering device 84, and the dryer 86 are arranged in parallel on the basis of the flow direction of the exhaust gas, but these devices may be arranged in series. It may be a combination of serial and parallel. Further, for example, at least one of the dryer 86 and the watering device 84 may not be provided. Further, the merging unit 17 may be provided after exhaust gases from the drying pulverizer 82, the water sprinkler 84, and the dryer 86 are merged. For example, the merging unit 17 may be provided on the upstream side of the gas processing unit 80, for example, between the extraction unit 13 and the branching unit 26. Further, the merging portion 18 may be provided on the downstream side of the branching portion 26. Further, the branch portion 26 may not be provided, and the SP exhaust gas G1 flowing through the flow path P1B is merged with the exhaust gas from the mercury collection dust collector 10B at the merge portion 18, and then the entire amount is introduced into the gas processing portion 80. Also good.

  As the dust collector 15, an electric dust collector can be used when the raw material dust to be collected has high mercury adsorption performance. In the case of cement clinker production, the electrostatic precipitator is operated at about 100 ° C. because of the relationship with the specific resistance of the raw material dust. At such a low temperature, the raw material dust usually has sufficient mercury adsorption performance.

  A part of the exhaust gas from the merging unit 18 may be branched into the branching unit 26 without being introduced into the gas processing unit 80, and then introduced into the dust collector 15 through the flow path P <b> 1 </ b> F. However, when the mercury concentration in the exhaust gas is high, it is preferable to reduce the amount of the exhaust gas introduced into the dust collector 15 from the flow path P1F by bypassing the gas processing unit 80. When the mercury concentration in the exhaust gas from the flow path P9 is high, the mercury concentration can be reduced by increasing the amount of raw material supplied from the raw material input device 14 or lowering the temperature in the dust collector 15. . In this case, it is preferable to use a bag filter as the dust collector 15.

  The raw material dust collected by the dust collector 15 flows through the flow path P5A, and is usually introduced into the raw material silo 20 through a mixing silo (not shown). Thus, in the cement clinker manufacturing facility 200, almost the entire amount of the raw material dust collected by the dust collector 15 can be reused as a raw material again. In the material silo 20, the other material is circulated through the flow path P <b> 5 </ b> B and introduced into the charging machine 24. The raw material dust is supplied together with other cement raw materials from the feeder 24 to the flow path P1A on the inlet side of the uppermost cyclone 12 of the suspension preheater SP. Here, it merges with the gas (exhaust gas) rising in the cyclone. In the uppermost cyclone 12, the mercury adsorbed on the raw material dust does not have to be completely evaporated. For example, it may evaporate after dropping into the lower cyclone like the cement raw material 72. Thus, most mercury can be evaporated by putting it in a high-temperature cyclone. In this way, the SP exhaust gas G1 containing mercury discharged from the suspension preheater SP is extracted by the flow path P1B which is the main flue by the suction of the SP fan 23.

  The cement raw material 74 flowing down the suspension preheater SP is introduced into the kiln 60. The cement raw material 74 is fired by the combustion of the burner 64 in the kiln 60, and a cement clinker is generated. The cement clinker obtained in the kiln 60 is taken out after being cooled by the clinker cooler 62. The cement clinker manufacturing apparatus 50 has a calcining furnace including a burner 61 below the suspension preheater. An extraction duct 66 from the clinker cooler 62 is connected to the calciner. In addition, the cement clinker manufacturing apparatus 50 is not limited to such a structure. For example, the cyclone 12 corresponding to the raw material collector may not be the uppermost cyclone and may be the second and subsequent cyclones.

  The flow paths P1A, P1B, P1C, P1D, P1E, and P1F in FIG. 5 correspond to the flow path P1 in FIGS. The flow path P5A and the flow path P5B in FIG. 5 correspond to the flow path P5 in FIGS.

  In the cement clinker manufacturing facility 200 of FIG. 5, the mercury recovery unit 10 of the mercury recovery apparatus 150 causes the mercury contained in the SP exhaust gas G1 to be adsorbed on the mercury adsorbent, and is recovered by the mercury collecting dust collector 10B. Is extracted and processed. At the same time, in the gas processing unit 80, the raw material containing unburned components is mixed with the exhaust gas and the mercury contained in the exhaust gas is adsorbed, and then the dust containing the raw material is collected by the dust collector 15. The collected raw material dust is introduced into the suspension preheater SP together with other cement raw materials.

  After the introduction, mercury is removed by evaporation and becomes a cement clinker together with other raw materials. On the other hand, evaporated mercury is concentrated in the SP exhaust gas G1 discharged from the suspension preheater SP. Thus, since mercury is reduced or removed from the SP exhaust gas G1 in which mercury is concentrated in the mercury recovery unit 10, mercury released into the atmosphere can be efficiently reduced.

  Next, an embodiment of the mercury recovery method of the present invention will be described. The mercury recovery method according to the present embodiment is a mercury recovery method for recovering mercury from a gas flowing in the flow path P1 (P1A to P1F) from upstream to downstream, and includes the following steps. By repeating the following series of steps, the mercury recovery apparatus can be operated continuously.

A raw material recovery process for recovering a solid raw material by a raw material recovery unit 12 from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned components. Flow through a flow path P1 (P1C) obtained by recovering the solid raw material. Extraction process of extracting a part of the mercury-containing gas in the extraction unit 13 ・ Mercury recovery for mixing the extracted mercury-containing gas and the mercury adsorbent to recover the mercury adsorbent adsorbing the mercury contained in the mercury-containing gas A dust collection step / raw material dust that collects the raw material dust that adsorbs mercury in the mercury-containing gas that flows through the flow path downstream of the process / bleeding unit 13 and flows through the flow path at a temperature lower than the mixed gas, A merging step for merging with the gas flowing through the flow path P1 (P1A) on the upstream side of the raw material recovery unit 12

  The mercury recovery method described above may be performed using, for example, any one of the mercury recovery apparatuses 100, 110, 120, 130, and 150 shown in FIGS. 1 to 5 or another mercury recovery apparatus. May be. The contents of each process can be performed by applying the explanation contents of the mercury recovery apparatus described above. According to this mercury recovery method, mercury can be recovered efficiently and the amount of mercury released to the atmosphere can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment at all.

  According to the present disclosure, it is possible to provide a mercury recovery apparatus and a mercury recovery method capable of efficiently recovering mercury contained in a gas and reducing the amount of mercury released into the atmosphere.

  DESCRIPTION OF SYMBOLS 10 ... Mercury recovery part, 10A ... Dosing machine, 10B ... Mercury collection dust collector, 10C ... Dosing machine, 10D ... Remover, 11 ... Confluence part, 12 ... Raw material collection | recovery device (top cyclone), 13 ... Extraction part, DESCRIPTION OF SYMBOLS 14 ... Raw material charging machine, 15 ... Dust collector, 17, 18 ... Junction part, 20 ... Raw material silo, 23 ... SP fan, 24 ... Loading machine, 26 ... Branching part, 50 ... Cement clinker manufacturing apparatus, 60 ... Kiln, 61, 64 ... Burner, 62 ... Clinker cooler, 66 ... Extraction duct, 72, 74 ... Cement raw material, 80 ... Gas treatment section, 82 ... Drying and grinding machine, 84 ... Sprinkler, 86 ... Dryer, 100, 110, 120 , 130, 150 ... mercury recovery equipment, 200 ... cement clinker production facility.

Claims (11)

A mercury recovery device that recovers mercury from gas flowing from upstream to downstream in a flow path,
A raw material recovery device for recovering the solid raw material from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned components;
An extraction part for extracting the mercury-containing gas flowing through the flow path downstream of the raw material recovery unit;
A mercury recovery part that mixes the mercury-containing gas extracted in the extraction part and the mercury adsorbent, and recovers the mercury adsorbent that adsorbs the mercury contained in the mercury-containing gas;
Downstream of the extraction unit, a dust collector that collects raw material dust containing mercury in the mercury-containing gas flowing through the flow path at a temperature lower than the mixed gas;
And a flow path for joining the raw material dust to a gas flowing through the flow path on the upstream side of the raw material recovery device.   2. The mercury recovery apparatus according to claim 1, further comprising a merging unit that joins the solid raw material containing unburned matter to the mercury-containing gas that circulates through the flow path between the extraction unit and the dust collector.   3. The mercury recovery apparatus according to claim 1, further comprising a remover that removes a solid content from the extracted mercury-containing gas between the extraction unit and the mercury recovery unit.   The mercury recovery apparatus according to claim 3, wherein the remover maintains a temperature of the mercury-containing gas at 200 ° C. or higher.   The mercury recovery apparatus according to any one of claims 1 to 4, further comprising a circulation channel that joins at least a part of the mercury adsorbent collected by the mercury recovery unit to the mercury-containing gas.   The mercury recovery unit according to any one of claims 1 to 5, further comprising a flow path that returns a gas obtained by reducing mercury from a mercury-containing gas to the flow path on the downstream side of the extraction unit in the mercury recovery unit. apparatus.   The said dust collector is a mercury collection | recovery apparatus as described in any one of Claims 1-6 which dusts the raw material dust containing the mercury in the mercury containing gas which is 300 degrees C or less. The raw material recovery device is a cyclone of a cement clinker manufacturing apparatus having a kiln with a suspension preheater,
A charging machine for supplying the solid raw material to the exhaust gas inlet side of the cyclone;
The mercury recovery device according to any one of claims 1 to 7, further comprising: the extraction unit that extracts the exhaust gas that is the mercury-containing gas on an exhaust gas outlet side of the cyclone.   The mercury recovery apparatus according to any one of claims 1 to 8, wherein the solid material includes at least one of coal ash and incineration ash. A mercury recovery method for recovering mercury from gas flowing from upstream to downstream in a flow path,
A raw material recovery step of recovering the solid raw material by a raw material recovery unit from a mixed gas containing a mercury-containing gas and a solid raw material containing unburned components;
An extraction step of extracting a part of the mercury-containing gas flowing through the flow path obtained by collecting the solid raw material in an extraction unit;
A mercury recovery step of mixing the extracted mercury-containing gas and the mercury adsorbent and recovering the mercury adsorbent adsorbing the mercury contained in the mercury-containing gas;
Downstream of the extraction part, a dust collection step of collecting the raw material dust adsorbing mercury in the mercury-containing gas flowing through the flow path at a temperature lower than the mixed gas;
And a merging step of merging the raw material dust with the gas flowing through the flow path on the upstream side of the raw material collector.   The mercury recovery method according to claim 10, wherein in the dust collection step, raw material dust containing mercury in a mercury-containing gas having a temperature of 300 ° C or lower is collected.

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