JP2008175505A - Thermal decomposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal decomposition apparatus, surely discharging thermally decomposed gas remaining in a thermal decomposition furnace and its peripheral devices in case of an emergency stop of the apparatus, and stopping the occurrence of gas explosion to improve safety and economical efficiency. <P>SOLUTION: In this thermal decomposition apparatus, material to be treated is heated in a thermal decomposition furnace 100 to cause thermal decomposition, and thermal decomposition gas is introduced into a thermal decomposition gas combustion furnace 25. A gas ejection passage 6 for emergency is provided to diverge from a thermal decomposition gas passage 8 in an upstream region of the thermal decomposition gas combustion furnace 25, the gas ejection passage 6 for emergency is provided with an emergency gas combustion device 2 for burning the introduced ejection gas, and a gas shut-off device 9 for shutting off circulation of thermal decomposition gas to the thermal decomposition gas combustion furnace 25 is provided between a diverge part 7 of the gas ejection passage 6 and the thermal decomposition gas combustion furnace 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is applied to a sludge carbonization treatment facility and the like, and heats and decomposes an object to be treated including dehydrated sludge by heating with a heating gas in a pyrolysis furnace, and pyrolyzing the pyrolysis gas discharged from the pyrolysis furnace The present invention relates to a pyrolysis apparatus configured to be introduced into a pyrolysis gas combustion furnace through a gas passage.

FIG. 3 shows that dehydrated sludge is heated and dried in a dryer and introduced into a pyrolysis furnace (carbonization furnace), and the dehydrated sludge dried in the pyrolysis furnace is heated with combustion heating gas from the pyrolysis furnace combustion furnace. It is a principal part system diagram of the carbonization processing equipment of the sludge comprised so that a carbide | carbonized_material may be produced | generated from the said dehydrated sludge by heating and decomposing | disassembling.
In FIG. 3, the dewatered sludge is introduced into the dryer 20, heated and dried by a dryer circulating gas from a dryer combustion furnace (pyrolysis gas combustion furnace) 25 described later, and then introduced into the pyrolysis furnace 100. It has come to be. A pyrolysis furnace combustion furnace 21 is installed in association with the pyrolysis furnace 100, and in this pyrolysis furnace combustion furnace 21, a dryer circulating gas and auxiliary fuel from a dryer combustion furnace 25 described later are used for combustion. By burning with air, a high-temperature combustion gas of about 1100 ° C. is generated.

In the pyrolysis furnace 100, the dried sludge from the dryer 20 is heated and thermally decomposed by a high-temperature combustion heating gas of about 1100 ° C. generated in the pyrolysis furnace combustion furnace 21 to decompose carbides from the dried sludge. Is generated. The carbide is cooled while being conveyed by the carbide cooling conveyor 23, and is humidified by the humidifier 24 and then stored in a carbide hopper (not shown).
In the pyrolysis furnace 100, the pyrolysis furnace gas (exhaust gas) after carbonizing the dried sludge is preheated with combustion air by the air preheater 22, subjected to a necessary purification process, and discharged into the outside air. Has been.
Then, the pyrolysis gas from the pyrolysis furnace 100 is introduced into the dryer combustion furnace 25 through the pyrolysis gas pipe 8. In the dryer combustion furnace 25, the auxiliary fuel and air preheater 22 preheats. The pyrolysis gas is burned using the combustion air thus produced, and a combustion gas of about 950 ° C. is generated. This combustion gas is supplied to the pyrolysis furnace combustion furnace 21 and the dryer 20.

Incidentally, Patent Document 1 (Japanese Patent Application Laid-Open No. 11-241815) discloses a waste treatment facility equipped with a pyrolysis furnace. In this treatment facility, an emergency shut-off valve is provided at the time of emergency stop of the pyrolysis device. Close and shut off the flammable gas existing section, confine the flammable gas of the entire system in the system, and then replace the flammable gas in the shutoff section with inert gas, It is made to burn in a reburning furnace.
Further, Patent Document 2 (Japanese Patent Laid-Open No. 2006-35117) discloses a waste treatment facility equipped with a pyrolysis furnace. In this treatment facility, the induction blower is stopped when the pyrolysis device is stopped in an emergency. The pyrolysis gas that continues to be generated from the pyrolysis furnace is guided to the safety torch.

Japanese Patent Laid-Open No. 11-241815 JP 2006-35117 A

  However, in the thermal decomposition apparatus equipped in the sludge carbonization facility as shown in FIG. 3, the heat connected from the thermal decomposition furnace 100 to the dryer combustion furnace 25 when the thermal decomposition apparatus is in an emergency stop. If the pyrolysis gas in the system of the cracking gas pipe 8 remains in the system without being sufficiently discharged, there is a problem that it is likely to cause an explosion or the like.

  In Patent Document 1 (Japanese Patent Laid-Open No. 11-241815), at the time of an emergency stop of the thermal decomposition apparatus as described above, the emergency shut-off valve is closed to shut off the existing section of the combustible gas, thereby combusting the entire system. In order to solve the above-mentioned problem, the combustible gas is confined in the system, and then the combustible gas in the shut-off section is replaced with the inert gas. If the combustible gas is an explosive gas mixture in the system where the gas is confined, there is still a possibility of inducing a gas explosion caused by fire types such as static electricity and residual heat in the system. ing.

  Further, in Patent Document 1, a pusher fan (push blower) for pushing the inert gas into the pyrolysis furnace is provided in the gas passage between the inert gas cylinder and the pyrolysis furnace, and the pyrolysis furnace outlet side is provided. An emergency damper is installed in the pyrolysis gas passage of the engine, and at the time of emergency stop, the emergency shut-off valve is closed to shut off the flammable gas existing section, and then the emergency damper is opened. Since the pyrolysis gas in the pyrolysis gas pipe line between the furnace and the emergency damper is replaced with an inert gas, the solid solids in the pyrolysis pipe line are sealed by the push fan to the pyrolysis furnace and its front and rear seals. There is a risk of gas leakage due to poor sealing.

  On the other hand, in Patent Document 2, the induction blower is stopped at the time of an emergency stop as described above, and the pyrolysis gas that continues to be generated from the pyrolysis furnace is safely kept in a state where the pyrolysis furnace and the subsequent equipment are in circulation. Since it is guided to the torch, there is a possibility of inducing a gas explosion when air inhalation or flammable gas leakage occurs in the subsequent equipment.

  The present invention has been made in view of such a situation, and its purpose is to reliably discharge the pyrolysis gas remaining in the pyrolysis furnace and its surrounding devices to the outside of the system at the time of emergency stop of the apparatus. An object of the present invention is to provide a thermal decomposition apparatus capable of preventing the occurrence of gas explosion and improving safety and economy.

  In order to solve the above-described problems of the prior art, the present invention introduces an object to be processed including dehydrated sludge into a pyrolysis furnace, and heats the object to be processed with a heating gas in the pyrolysis furnace for thermal decomposition. In the pyrolysis apparatus configured to introduce the pyrolysis gas discharged from the pyrolysis furnace into the pyrolysis gas combustion furnace through the pyrolysis gas passage, the pyrolysis gas in the upstream portion of the pyrolysis gas combustion furnace An emergency gas extraction passage branched from the passage is provided, an emergency gas combustion device for combusting the extracted gas introduced into the emergency gas extraction passage is provided, and the branch portion of the emergency gas extraction passage and the heat In the pyrolysis gas passage located between the pyrolysis gas combustion furnace and a pyrolysis gas combustion furnace, a gas shut-off device that shuts off the flow of pyrolysis gas to the pyrolysis gas combustion furnace is provided.

Specifically, in the present invention, the following configuration is preferable.
(1) The emergency gas extraction passage is provided with an emergency induction fan that sucks the gas in the pyrolysis gas passage and sends it to the emergency gas combustion device (claim 2).
(2) The pyrolysis gas passage is provided with a stationary induction fan that sucks the gas in the pyrolysis gas passage and sends it to the pyrolysis gas combustion furnace.
(3) On the upstream side of the pyrolysis furnace, an inert gas supply means for supplying an inert gas into the pyrolysis furnace is provided (claim 4).
(4) A water-sealed tank that seals the extracted gas that has passed through the emergency gas extraction passage is installed at an upstream portion of the emergency induction fan of the emergency gas extraction passage. After passing through a water-sealed tank, it is configured to be sucked into the emergency induction fan (claim 5).

  In the present invention, the pyrolysis gas passage located between the branch portion of the emergency gas extraction passage and the pyrolysis gas combustion furnace is formed in a plurality of parallel passages, A gas shut-off device is provided (Claim 6).

  According to the present invention, the emergency gas extraction passage branched from the pyrolysis gas passage in the upstream portion of the pyrolysis gas combustion furnace, and the emergency gas combustion apparatus for burning the extraction gas introduced into the emergency gas extraction passage And a gas shutoff device that shuts off the flow of pyrolysis gas to the pyrolysis gas combustion furnace in the pyrolysis gas passage located between the branch of the emergency gas extraction passage and the pyrolysis gas combustion furnace. Therefore (Claim 1), at the time of emergency stop such as failure of the pyrolysis furnace, the gas shut-off device is operated simultaneously with the emergency stop to shut off the flow of pyrolysis gas to the pyrolysis gas combustion furnace, The emergency gas extraction passage branched from the pyrolysis gas passage is communicated, for example, by discharging water from the water-sealed tank, and the pyrolysis gas in the pyrolysis furnace and the passage leading to the pyrolysis furnace is used as an emergency. Gas extraction passage Introducing the emergency gas combustion device through, it is possible to combustion treatment in the emergency gas combustion apparatus.

  Therefore, according to the present invention, at the time of an emergency stop, the pyrolysis gas in the pyrolysis furnace and the passage leading to the pyrolysis furnace does not remain and does not leak to the pyrolysis gas combustion furnace side. The gas can be introduced into the emergency gas extraction passage and burned by the emergency gas combustion device. The pyrolysis gas can be confined in the pyrolysis furnace and in the passage leading to the pyrolysis furnace, and gas explosion can be induced by this. Therefore, the safety of the whole plant at the time of emergency stop can be maintained, and the economic efficiency can be improved.

  Further, if an emergency induction fan is provided in the emergency gas extraction passage (Claim 2), or a stationary induction fan is provided in the pyrolysis gas passage (Claim 3), the emergency stop can be performed at the time of the emergency stop. Since the pyrolysis gas in the pyrolysis furnace and in the passage leading to the pyrolysis furnace can be sucked and sent out to the emergency gas combustion apparatus by the emergency induction fan or the stationary induction fan, the above-mentioned Patent Document 1 When the inert gas is pushed into the pyrolysis furnace and peripheral equipment by a push-in fan at the time of an emergency stop of the plant as in the case of the above-mentioned technique, the fine solids in the pyrolysis passage are put into the pyrolysis furnace and its The front and rear seal portions are not clogged, and it is possible to avoid the occurrence of a sealing failure and gas leakage due to this.

  Further, if the inert gas is supplied from the upstream side of the pyrolysis furnace into the pyrolysis furnace by the inert gas supply means (Claim 4), the inert gas is supplied from the upstream side of the pyrolysis furnace. By injecting, the entire pyrolysis gas passage in the pyrolysis furnace and on the downstream side of the pyrolysis furnace can be replaced with the inert gas. Therefore, the inert gas can be distributed uniformly and efficiently over the entire path of the pyrolysis gas, and as a result, the amount of the inert gas used can be reduced.

  In addition, a water-sealed tank is installed upstream of the emergency induction fan in the emergency gas extraction passage, and the extracted gas that has passed through the emergency gas extraction passage passes through the water-sealed tank and is then sucked into the emergency induction fan. By doing so, the emergency gas extraction passage can be reliably shut off by the water in the water-sealed tank during steady operation, while the emergency operation is performed by discharging the water from the water-sealed tank at the time of emergency stop. The gas extraction passage can be opened to ensure communication with the emergency gas combustion device. The emergency gas extraction passage cannot be opened due to tar content in the pyrolysis gas. The suction fan can be efficiently inhaled.

  In the present invention, a pyrolysis gas passage located between the branch portion of the emergency gas extraction passage and the pyrolysis gas combustion furnace is formed in a plurality of parallel passages, and the gas shut-off device is provided in each of the parallel passages. If it is configured to provide (Claim 6), even when one gas shut-off device cannot be opened due to tar content in the pyrolysis gas during normal operation, a sound side gas shut-off device is replaced instead. It can be opened and used, and the operation efficiency of the plant can be maintained high.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First embodiment]
FIG. 1 is a system diagram of an essential part of a sludge carbonization facility equipped with a thermal decomposition apparatus according to a first embodiment of the present invention.
In the carbonization treatment facility shown in FIG. 1, the dewatered sludge is introduced into the dryer 20 from the cake quantitative feeder 27 and heated by a dryer circulating gas from a dryer combustion furnace (pyrolysis gas combustion furnace) 25 described later. After being dried, it is introduced into the pyrolysis furnace 100 through the dried sludge quantitative feeder 28 and the dried sludge conveyance path 30. A pyrolysis furnace combustion furnace 21 is installed in association with the pyrolysis furnace 100, and the pyrolysis furnace combustion furnace 21 burns dryer circulating gas and auxiliary fuel from a dryer combustion furnace 25 described later. By burning using industrial air, a high-temperature combustion gas of about 1100 ° C. is generated.

The pyrolysis furnace 100 generates carbides from the dried sludge by heating and decomposing the dried sludge from the dryer 20 with a high-temperature combustion heating gas of about 1100 ° C. generated in the pyrolysis furnace combustion furnace 21. It is a furnace. The carbide is cooled while being conveyed by the carbide cooling conveyor 23, and is humidified by the humidifier 24 and then stored in a carbide hopper (not shown).
In the pyrolysis furnace 100, the pyrolysis furnace gas (exhaust gas) after carbonizing the dried sludge is preheated with combustion air by the air preheater 22, and then subjected to a necessary purification process in the outside air. It has been discharged.
Further, an inert gas supply means 10 for supplying an inert gas into the pyrolysis furnace 100 is provided at a portion upstream of the pyrolysis furnace 100 in the dried sludge conveyance path 30.

Pyrolysis gas from the pyrolysis furnace 100 is introduced into the dryer combustion furnace 25 through a dust collector 26 and a pyrolysis gas pipe (pyrolysis gas passage) 8. In the dryer combustion furnace 25, auxiliary fuel is supplied. In addition, the pyrolysis gas is combusted using the combustion air preheated by the air preheater 22 and introduced through the air pipe 31, and a combustion heating gas of about 950 ° C. is generated. This combustion heating gas is supplied to the pyrolysis furnace combustion furnace 21 and the dryer 20 through the combustion gas pipe 32.
In the dryer 20, the dryer circulating gas after the dehydrated sludge from the cake quantitative feeder 27 is heated and dried enters the circulation path through the dryer sludge dust collector 29.

A stationary induction fan 1 is provided in the middle of the pyrolysis gas pipe 8. During steady operation of the plant, the stationary induction fan 1 sucks pyrolysis gas from the pyrolysis furnace 100 side. It feeds into a dryer combustion furnace (pyrolytic gas combustion furnace) 25.
Further, an emergency use branching from the pyrolysis gas pipe 8 upstream of the dryer combustion furnace 25 (the branch portion is indicated by reference numeral 7) downstream of the stationary induction fan 1 of the pyrolysis gas pipe 8. A gas extraction pipe (emergency gas extraction passage) 6 is provided, and this emergency gas extraction pipe 6 is connected to an emergency gas combustion furnace 2 for burning the extracted gas introduced through the emergency gas extraction pipe 6. Has been.

In the middle of the emergency gas extraction pipe 6, a water seal tank 4 for sealing the extracted gas that has entered the emergency gas extraction pipe 6 in order from the branching portion 7 to the downstream side, An emergency induction fan 3 that sucks the pyrolysis gas in the cracking gas pipe 8 and sends it to the emergency gas combustion furnace 2 is provided.
The water seal tank 4 has a function as an opening / closing means. When the water is stored, the emergency gas extraction pipe 6 is closed, and when the water is discharged, the emergency gas extraction pipe 6 is opened. The emergency induction fan 3 and the emergency gas combustion furnace 2 are configured to communicate with each other. Therefore, the bottom of the water-sealed tank 4 is provided with a discharge pipe 5 for discharging the stored water and an opening / closing valve 5a for opening and closing the discharge pipe 5.

  On the other hand, the pyrolysis gas pipe 8 located between the branch portion 7 of the emergency gas extraction pipe 6 and the dryer combustion furnace 25 has a shut-off that blocks the flow of pyrolysis gas to the dryer combustion furnace 25. A damper (gas shut-off device) 9 is provided.

  In the sludge carbonization equipment constructed as described above, when the thermal decomposition apparatus is stopped due to a power failure or the like, the on-off valve of the water-sealed tank 4 provided in the emergency gas extraction pipe 6 that is closed during normal operation is used. When the water 5a is opened and the water stored in the water-sealed tank 4 is discharged from the discharge pipe 5, the pyrolysis gas remaining in the pyrolysis gas passage from the pyrolysis furnace 100 to the pyrolysis gas pipe 8 is used for emergency. The gas is introduced into the gas extraction pipe 6, passes through the water-sealed tank 4, is sucked into the emergency induction fan 3, and is sent from the emergency induction fan 3 to the emergency gas combustion furnace 6 for combustion treatment.

  As described above, according to the first embodiment of the present invention, the emergency gas extraction pipe 6 branched from the pyrolysis gas pipe 8 upstream of the dryer combustion furnace (pyrolysis gas combustion furnace) 25 and the emergency gas are provided. An emergency gas combustion furnace 2 for burning the pyrolysis gas introduced and extracted from the extraction pipe 6 is provided, and the heat located between the branch portion 7 of the emergency gas extraction pipe 6 and the dryer combustion furnace 25 is provided. Since the cracking gas pipe 8 is provided with the shut-off damper 9 for shutting off the flow of the pyrolysis gas to the dryer combustion furnace 25, at the time of emergency stop such as failure of the pyrolysis furnace 100 or power failure, The shut-off damper 9 is operated to shut off the flow of the pyrolysis gas to the dryer combustion furnace 25, and the emergency gas outlet pipe 6 branched from the pyrolysis gas pipe 8 is sealed by opening the on-off valve 5. The tank 4 is opened to communicate with the inside of the pyrolysis furnace 100. Then, the pyrolysis gas in the passage leading to the pyrolysis furnace 100 can be introduced into the emergency gas combustion furnace 2 through the emergency gas extraction pipe 6 and burned in the emergency gas combustion furnace 2.

  Therefore, according to the first embodiment, during the emergency stop, the pyrolysis gas in the pyrolysis furnace 100 and the passage leading to the pyrolysis furnace 100 does not remain and leaks to the dryer combustion furnace 25 side. Without being carried out, the gas can be completely introduced into the emergency gas extraction pipe 6 and completely burned in the emergency gas combustion furnace 2, and the pyrolysis gas into the pyrolysis furnace 100 and to the passage leading to the pyrolysis furnace 100 can be obtained. There is no possibility of confinement of gas and gas explosion induction by this, and the safety of the whole plant at the time of emergency stop can be secured and maintained.

  In the first embodiment of the present invention, the emergency induction fan 3 is provided in the emergency gas extraction pipe 6, or the stationary induction fan 1 is provided in the pyrolysis gas pipe 8, so that the emergency As the conventional induction fan 3 or the stationary induction fan 1 sucks the pyrolysis gas in the pyrolysis furnace 100 and the passage leading to the pyrolysis furnace 100 and sends it to the emergency gas combustion furnace 2 side, as in the prior art In the emergency stop of the plant, the inert gas is pushed into the pyrolysis furnace and peripheral equipment by the push-in fan and replaced, so that fine solids in the pyrolysis passage are clogged in the pyrolysis furnace and the seals around it. Therefore, it is possible to avoid the occurrence of poor sealing and gas leakage due to this.

Moreover, the inert gas supply means 10 is configured to supply an inert gas into the pyrolysis furnace 100 from the upstream side of the pyrolysis furnace 100, and the inert gas is injected from the upstream side of the pyrolysis furnace 100. Since the entire pyrolysis furnace 100 and the pyrolysis gas pipe 8 on the downstream side of the pyrolysis furnace 100 are replaced with the inert gas, the inert gas is spread over the entire pyrolysis gas passage. It can be distributed uniformly and efficiently, and as a result, the amount of inert gas used is small.
Further, a water-sealed tank 4 is installed upstream of the emergency induction fan 3 of the emergency gas extraction pipe 6 so that the extracted gas passing through the emergency gas extraction pipe 6 is passed through the water-sealed tank 4. Therefore, it does not happen that the water-sealed tank 4 cannot be opened due to the tar content in the pyrolysis gas, and the emergency induction fan 3 can be efficiently inhaled.

[Second Embodiment]
FIG. 2 is a system diagram of an essential part near the dryer combustion furnace according to the second embodiment of the present invention.
In the second embodiment, a pyrolysis gas pipe 8 positioned between the branch portion 7 of the emergency gas extraction pipe 6 and the dryer combustion furnace 25 is formed in the plurality of parallel passages 8a and 8b. In each of the parallel passages 8a and 8b, cutoff dampers (gas cutoff devices) 9a and 9b are provided.
According to the second embodiment, even when one shut-off damper (for example, 9a) cannot be opened due to tar or the like in the pyrolysis gas during normal operation, a sound-side shut-off damper (for example, 9b) can be opened and used, and the operation efficiency of the plant can be maintained high.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

FIG. 2 is a system diagram of a principal part showing the sludge carbonization equipment equipped with the thermal decomposition apparatus according to the first embodiment of the present invention. It is a principal part systematic diagram which shows the dryer combustion furnace vicinity which concerns on 2nd Embodiment of this invention. It is a principal part systematic diagram which shows the carbonization processing equipment which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stationary induction fan 2 Emergency gas combustion furnace 3 Emergency induction fan 4 Water seal tank 5 Discharge pipe 5a On-off valve 6 Emergency gas extraction pipe 7 Branch part 8 Pyrolysis gas pipe 8a, 8b Parallel passage 9, 9a, 9b Shut-off damper (gas shut-off device)
10 Inert gas supply means 20 Dryer 21 Pyrolysis furnace combustion furnace 25 Dryer combustion furnace (pyrolysis gas combustion furnace)
100 pyrolysis furnace

Claims (6)

  An object to be treated including dehydrated sludge is introduced into a pyrolysis furnace, and the object to be treated is thermally decomposed by heating gas in the pyrolysis furnace, and the pyrolysis gas discharged from the pyrolysis furnace is pyrolyzed gas. In the pyrolysis apparatus configured to be introduced into the pyrolysis gas combustion furnace through a passage, an emergency gas extraction passage branched from the pyrolysis gas passage at an upstream portion of the pyrolysis gas combustion furnace is provided, An emergency gas combustion device for combusting the extracted gas introduced into the emergency gas extraction passage is provided, and the pyrolysis gas passage located between the branch portion of the emergency gas extraction passage and the pyrolysis gas combustion furnace is provided. A pyrolysis apparatus comprising a gas shut-off device for shutting off the flow of pyrolysis gas to the pyrolysis gas combustion furnace.   2. The pyrolysis according to claim 1, wherein the emergency gas extraction passage is provided with an emergency induction fan that sucks gas from the pyrolysis gas passage and sends the gas to the emergency gas combustion device. apparatus.   The heat according to claim 1 or 2, wherein the pyrolysis gas passage is provided with a stationary induction fan that sucks the gas in the pyrolysis gas passage and sends it to the pyrolysis gas combustion furnace. Disassembly equipment.   The pyrolysis according to any one of claims 1 to 3, wherein an inert gas supply means for supplying an inert gas into the pyrolysis furnace is provided upstream of the pyrolysis furnace. apparatus.   A water seal tank that seals the extracted gas that has passed through the emergency gas extraction passage is installed upstream of the emergency induction fan in the emergency gas extraction passage. The thermal decomposition apparatus according to claim 2, wherein the thermal decomposition apparatus is configured to be sucked into the emergency induction fan after passing through.   A pyrolysis gas passage located between the branch portion of the emergency gas extraction passage and the pyrolysis gas combustion furnace is formed in a plurality of parallel passages, and each of the parallel passages is provided with the gas shut-off device. The thermal decomposition apparatus according to claim 1, wherein the thermal decomposition apparatus is provided.

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