JP4458972B2 - Waste pyrolysis treatment system - Google Patents

Description

  The present invention relates to a waste pyrolysis processing system for processing a workpiece such as waste by pyrolysis.

  Conventionally, as a waste treatment system for treating undegraded and untreated waste containing various pollutants and converting them into usable materials, it has been disclosed in JP 2000-202419 A (Patent Document 1). Thermal decomposition systems for treating such wastes by thermal decomposition are known.

  In such a waste treatment system, an object to be treated such as waste is supplied into a thermal decomposition furnace by a waste supply device via a pretreatment device, and is thermally decomposed at a temperature of about 550 ° C. in the thermal decomposition furnace. It is processed. As a general pyrolysis furnace, for example, an externally heated rotary kiln that heats a rotary drum from the outside is used.

  The organic polymer gas generated by pyrolysis in the pyrolysis furnace is reformed at a temperature of about 1100 ° C. by a gas reformer to become a low molecular combustible gas, and then from about 900 ° C. to 200 ° C. by a gas cooler. It is rapidly cooled to about 0 ° C. and further purified by a gas purification device. In the gas cleaning process performed by the gas purification device, removal of carbon dust by a bag filter and gas water cleaning by water are performed. The combustible gas purified by the gas purification device is supplied to the gas usage destination through the induction blower, the water seal device, and the supply blower. These pyrolysis furnaces, gas reformers, gas coolers, and gas purification devices are controlled by the induction blower to a slightly negative pressure state, so that air easily enters from the outside. The main part is provided with a sealing structure so that the excessive amount does not enter.

However, in such a waste pyrolysis processing system, waste is pyrolyzed at about 550 ° C. in a pyrolysis furnace to generate pyrolysis gas. Even if the supply to the pyrolysis furnace is stopped, unpyrolyzed waste remains in the pyrolysis furnace and pyrolysis gas continues to be generated. However, even in such an emergency situation, it is required to safely remove the pyrolysis gas outside the process system. In addition, in order to increase the processing amount in the same plant, there are cases where a plurality of systems are installed and dealt with. However, if all the devices are arranged in a double row, the equipment cost and the operating cost become high.
JP 2000-202419 A

  The present invention has been made in view of the above-described conventional technical problems, and provides a waste pyrolysis processing system that can safely extract pyrolysis gas out of a process system even in an emergency. With the goal.

The invention of claim 1 includes a pyrolysis furnace for an object to be processed, such as crushed waste pyrolysis, the waste feed device for supplying the object to be treated such as the crushed waste into the pyrolysis furnace Gas reforming that accepts organic polymer gas generated by pyrolysis of the object to be treated in the pyrolysis furnace, reforms it into low-molecular combustible gas by high-temperature gas reforming treatment, and discharges it Receiving and cooling the combustible gas discharged from the gas reformer, receiving the gas cooler and discharging the combustible gas discharged from the gas cooler, purifying and removing impurities, Gas purifier that discharges purified combustible gas, and an attraction for attracting gas inside each of the pyrolysis furnace, gas reformer, gas cooler, and gas purifier while maintaining a negative pressure. The blower and the purified product attracted by the attracting blower In the waste pyrolysis process system comprising a feed blower for the combustible gas supplied to the gas utilization destination through the feed pipe, the waste feed system in an emergency failure or abnormal process such equipment constituted Stop the introduction of waste into the thermal decomposition furnace was stopped by the the emergency stopping means for stopping the attractant blower supply blower, generated from the gas reformer and the pyrolysis furnace during the operation of the emergency stop means And a gas venting means for venting the pyrolysis gas.

  According to a second aspect of the present invention, in the waste pyrolysis processing system according to the first aspect, the gas venting means is a gas gate valve composed of a stopper that can withstand a high temperature of the pyrolysis gas and a sealing granule. It is characterized by this.

  According to a third aspect of the present invention, in the waste thermal decomposition treatment system according to the first or second aspect, when the emergency stop means is operated, the waste gas decomposition means operates simultaneously with the upstream portion of the thermal decomposition furnace and gas cooling. An emergency inert gas injection means for injecting an inert gas into the downstream portion of the vessel is provided.

According to a fourth aspect of the present invention, in the waste pyrolysis processing system according to any one of the first to third aspects, the gas purification device includes a bag filter that scrapes carbon dust from the pyrolysis gas , and the waste heat The decomposition processing system includes a bypass means that operates simultaneously with the gas venting means and switches the pyrolysis gas flowing through the bag filter to a bypass line.

The invention of claim 5, Bei in any waste pyrolysis process system of claim 1, wherein the activated gas vent means at the same time, a gas cooler stop means to stop the Susuharai of the gas cooler It is characterized by that.

  The invention of claim 6 is the waste pyrolysis processing system according to claim 2, wherein the furnace pressure measuring means for measuring the furnace pressure of the pyrolysis furnace and the valve opening of the gas gate valve are adjusted, And a degassing control means for degassing while keeping the furnace pressure of the pyrolysis furnace constant at a slight negative pressure.

  ADVANTAGE OF THE INVENTION According to this invention, the waste pyrolysis processing system which can draw out pyrolysis gas outside a process system | strain safely also at the time of emergency can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the entirety of a plurality of waste pyrolysis treatment systems as one embodiment of the present invention. In FIG. 1, an object to be processed such as waste is supplied into a thermal decomposition furnace 103 by a waste supply device 102 via a pretreatment device 101 that performs crushing and iron recovery. The waste is processed by pyrolysis at a temperature of about 550 ° C. in the pyrolysis furnace 103. As the pyrolysis furnace 103, for example, an externally heated rotary kiln for heating a rotary drum from the outside is generally used, and an organic polymer gas generated by pyrolysis in the pyrolysis furnace 103 is used as a gas reformer 104. Here, it is reformed at a temperature of about 1100 ° C. to become a low-molecular combustible gas. The combustible gas is transferred to the gas cooler 105 where it is rapidly cooled from about 900 ° C. to about 200 ° C. and then supplied to the gas purification device 106. In the gas purification device 106, the cooled gas is purified to obtain a combustible gas from which impurities are removed. The gas purification device 106 includes a bag filter and a gas cleaning device, removes carbon dust with the bag filter, and gas cleaning with water is performed by the gas cleaning device 106. The combustible gas purified by the gas purification device 106 is supplied to the gas use destination through the induction blower 107, the water seal device 108, and the supply blower 109.

  On the other hand, the residue generated in the pyrolysis furnace 103 is discharged to the outside of the pyrolysis furnace 103 through the residue discharge device 111, valuable metal is recovered by the residue cooling, pulverization, and separation device 112, and the carbon residue is transferred to the granulator 113. It is sent and recycled as a granulated product. The cleaning water used for gas cleaning in the gas purification device 106 is sent to the water treatment device 114, neutralized, absorbed and adsorbed, subjected to purification water, and returned to the gas purification device 106.

  Note that the pyrolysis furnace 103, the gas reformer 104, the gas cooler 105, and the gas purification device 106 are controlled by the induction blower 107 in a slightly negative pressure state, so that the main part does not enter excessive air from the outside. Is provided with a sealing structure. In the pyrolysis processing system shown in FIG. 1, a reformed gas that is a combustible gas of a secondary material generated in the pyrolysis processing system is reused as an energy source of the pyrolysis furnace 103. In addition, it is recirculated for temperature adjustment of main components. Further, surplus gas generated by the system is burned according to the exhaust gas standard in a combustion furnace or the like, and released into the atmosphere.

  The content described above is a case where waste disposal is normally performed. If there is an emergency such as a failure of a component or a process abnormality, a safety torch 17 that combusts pyrolysis gas and releases it to the atmosphere, nitrogen on the upstream side of the pyrolysis furnace 3 and downstream side of the gas cooler 5 An inert gas is injected, and internal carbon ignition prevention gas injection lines 18 and 19 are provided. In FIG. 1, a granulation device 13, a safety torch 17, and a water treatment device 14 are provided as a shared plant of two systems as a shared system of the first and second systems.

  2-4 is explanatory drawing of the principal part in the waste pyrolysis processing system of the said embodiment. First, the state of the pyrolysis furnace 3 and the gas reformer 4 during normal processing operation will be described with reference to FIG. In the pyrolysis furnace 3, waste is continuously or intermittently supplied into the rotary drum 22 by the waste input device 21. An outlet hood 23 is disposed on the outlet side of the rotary drum 22, and the waste thermally decomposed in the rotary drum 22 is separated into a pyrolysis gas 24 and a pyrolysis residue 25 in the outlet hood 23. It is supposed to be discharged.

  The pyrolysis gas 24 is sent to the pyrolysis burner 27 through the gas communication pipe 26, mixed with the combustion air 28, and partially combusted (29) inside the reformer 4, and the gas is reformed at a temperature of about 1000 ° C. Quality processed. The reformer 4 has a concave shape and flows while reacting along the gas flow 30 to ensure the time required for reforming (gas reforming reaction time).

  On the other hand, the pyrolysis residue 25 is sent to the residue cooler 31. The rotating drum 22 having a cylindrical structure is supported by a support 32 so as to be freely rotatable. The rotating drum 22 is housed in the combustion chamber 33 and is heated by the burner 34 from the outside heat. Although the inside of the rotating drum 22 is controlled to a slightly negative pressure state, a seal structure is applied to a main part so that air does not enter excessively from the outside.

  Next, the state of the gas reformer 4, the gas cooler 5, the gas purification device 6, the induction blower 7, and the water sealing device 8 during normal processing operation will be described with reference to FIGS. The gas reformer 4 has a concave shape with a pre-reaction tower 40 and a post-reaction tower 41. Pyrolysis gas and air (oxidant) enter from the upper part of the pre-reaction tower 40, and gas exits from the upper part of the post-reaction tower 41. The reformed gas containing soot coming out from the upper part of the post-reaction tower 41 enters from the upper part of the gas cooler (smoke tube boiler) 5 installed in the vertical type, and flows downward in the heat transfer pipe 42 to 900 to 200 ° C. The gas is cooled to 0 ° C., folded at the gas cooler bottom 43, and flows upward in the quencher device 44. A product gas nozzle 45 and a water spray nozzle 46 are incorporated in the quencher device 44 to control the quencher outlet temperature. The gas is guided from this quencher device 44 to the bag filter 47. The pre-reaction tower 40 is provided with an air main valve 81 and an air sub valve 82. The main air valve 81 is a valve that is opened during operation and closed in an emergency. The air sub-valve 82 is a valve for closing the air during operation and opening it during an emergency to send the required minimum flow rate of air to the gas reformer 4 for cooling.

  A filter cloth 48 is attached in the bag filter 47, and the gas that has passed through the filter cloth 48 is sent to the gas cleaning device 49, and the dust 62 collected by the filter cloth 48 falls to the lower part and is discharged to the outside.

  The gas cleaning device 49 includes a cooler 50 and a gas cleaning tower 51, and has a concave shape including the inlet pipe 52. A water spray nozzle 53 is incorporated in the cooler 50, and a filler 54 and a water spray nozzle 55 are incorporated in the gas cleaning tower 51.

  The gas exiting the gas cleaning device 51 is sucked into the induction blower 7, sealed with water so as not to flow backward by the water seal device 8, and further sent to a supply blower (not shown) at the subsequent stage.

  A transfer screw 56 is installed at the bottom of the gas reformer 4. The transfer screw 56 transfers the gutter 57 collected at the bottom to the cooling screw 58. The cooling screw 58 cools the flange 57 and sends the flange 57 to a discharge mechanism 59 having, for example, a double damper configuration. The discharge mechanism 59 discharges the flange 57 to the outside while blocking air from the outside.

  The soot collected at the bottom of the gas cooler 5 is similarly cooled by the cooling screw 60 and sent to the discharge mechanism 61. The discharge mechanism 61 discharges the soot outside while blocking air from the outside.

  The inlet part of the gas cooler (smoke tube boiler) 5 is provided with a wiping nozzle 65 and a control valve 66, and has a structure in which wiping is periodically performed using steam generated in the boiler itself. Prevent occlusion in advance.

  The trap 62 collected by the bag filter 47 falls to the lower part, is cooled by the cooling screw 63, and is sent to a discharge mechanism 64 having, for example, a double damper configuration. The discharge mechanism 64 discharges the soot to the outside while blocking air from the outside.

  The outlet portion of the filter cloth 48 of the bag filter 47 is provided with a back-washing nozzle 67 and a control valve 68 that use nitrogen to wipe off the scissors 62 attached to the filter cloth 48. Further, the bag filter 47 is provided with an inlet valve 69 and an outlet valve 70 for partitioning the main body. The valves 69 and 70 are closed, and the bag bypass line 90 is opened to bypass the plant so that the temperature of the plant is increased or during an emergency. The body of the bug filter 47 can be isolated.

  Next, an emergency operation of the system will be described. In FIG. 1, a gas gate valve 20, an inert gas injection valve 19, and in FIG. 2, an inert gas injection valve 18 are provided for emergencies. In FIG. 5, gas gate valves 20a and 20b are provided in tunnel portions 71a and 71b of the gas reformers 4a and 4b in a plurality of systems. The gas gate valves 20a and 20b are composed of plugs 72a and 72b that can withstand high temperatures, granular bodies 73a and 73b, and lifting mechanisms 74a and 74b. Thus, normally, the plugs 72a and 72b are closed, and the material is sealed with the granular materials 73a and 73b. The safety torch 17 and the gas gate valves 20a and 20b are connected by gas pipes 75a and 75b. The safety torch 17 includes an exhaust tower 76, a combustion air blower 77, and a pilot burner 78. The pilot burner 78 uses 13A gas or the like and is always combusted. As shown in FIG. 6, a control device 91 configured by a computer that controls the overall operation of the system according to the present embodiment is provided. This control device 91 turns on / off the blowers 7 and 9, waste ON / OFF of the supply device 2, ON / OFF of the screw motor 56a, etc., opening / closing of the valves 18, 19, 20, etc., PWM control of the inverter 92 that converts the power of the power supply 93 and supplies it to the blowers 77, 79, etc. Various controls to be described later are executed according to predetermined logic.

  In a thermal decomposition processing system for processing an object to be processed such as waste by pyrolysis, in the event of an emergency such as a malfunction of a configured device or a process abnormality, the waste is put into the thermal decomposition furnace 3 under the control of the control device 91. The induction blower 7 is stopped, the supply blower 9 is also stopped, the gas gate valve 20 (20a or 20b) attached to the gas reformer 4 is opened, and the pyrolysis furnace 3 (3a or 3b) is opened. The pyrolysis gas that continues to be generated from the gas can be extracted to the safety torch 17. In this case, the configuration of venting is as shown in FIG. Here, the emergency operation of the system b will be described in detail. When the plug 72b constituting the gas gate valve 20b is pulled up, the granular material 73b falls from the gap with the valve seat, forms a gas flow furnace, and the gas pipe 75b. To the exhaust tower 76. An ascending airflow is always generated in the exhaust tower 76, which works to suck in the pyrolysis gas and can be safely exhausted simply by opening the gas gate valve 20b. Further, it is mixed with air sent from the combustion air blower 77, burned and exhausted. The granular material 73b is dropped into the tunnel portion 71b of the gas reformer 4b simultaneously with the opening operation of the gas gate valve 20b, and is discharged to the outside by the furnace screw 56 shown in FIG.

  The inert gas injection valves 18 and 19 are opened almost simultaneously with the operation of removing the pyrolysis gas that continues to be generated from the pyrolysis furnace 3b, and an inert gas (for example, nitrogen) is introduced into the upstream portion of the pyrolysis furnace 3b and the downstream portion of the gas cooler 5b. ). As a result, even when the pyrolysis gas is exhausted, the system is gradually filled with an inert gas such as nitrogen, and internal carbon can be prevented from being ignited even at high temperatures. Further, the bag filter 47 is switched to the bypass line 90 almost simultaneously with the operation of removing the pyrolysis gas that continues to be generated from the pyrolysis furnace 3b, so that the ignition of carbon in the bag filter 47 can be prevented. Furthermore, the pressure in the system can be stably maintained by stopping the scavenging of the gas cooler 5b almost simultaneously with the operation of removing the pyrolysis gas that continues to be generated from the pyrolysis furnace 3b. In addition, by providing the water sealing device 8 for preventing the backflow of the process gas, the water sealing device 8 can be pressure-separated from the equipment downstream from the water sealing device 8, and the emergency gas can be vented safely.

  The furnace pressure of the pyrolysis furnace 3b is measured by the pressure sensor 80, the opening degree of the gas gate valve 20b is adjusted, and the gas is vented while the furnace pressure of the pyrolysis furnace 3b is kept slightly constant. The opening degree of the gas gate valve 20b is adjusted by the lifting mechanism 74b.

  In addition, in the event of an emergency such as equipment failure or process abnormality, the introduction of waste into the pyrolysis furnace 3 (3a, 3b) is stopped, the induction blower 7 (7a, 7b) is stopped, and the supply blower 9 ( 9a, 9b) is stopped and cooling air is supplied to the pyrolysis burner 27 of the gas reformer 4 (4a, 4b) almost simultaneously with the operation of removing the pyrolysis gas continuously generated from the pyrolysis furnace 3 (3a, 3b). By providing the valve 82 for flowing the minimum necessary flow rate, the minimum air flow rate necessary for the burner cooling can be secured even when the main flow valve 81 is fully closed in an emergency.

  In addition, when the gas reformer 4 and the safety torch 17 must be separated depending on the location conditions of the place where the system is installed, as shown in FIG. 7, there is a safety torch 17 common to the gas reformers 4a and 4b. By providing the high temperature gas transfer blowers 79a and 79b between them, the pressure loss of the gas pipes 75a and 75b can be compensated and the pyrolysis gas can be transferred safely. In this case, as a means for degassing while keeping the furnace pressure (detected by the sensor 80) of the pyrolysis furnace 3 (3a, 3b) at a slight negative pressure, the controller 91 controls the high-temperature gas transfer blowers 79a, 79b. By controlling the rotation speed with an inverter, the pyrolysis gas can be extracted safely even if a change in gas generation amount or a change in pressure loss in the gas pipes 75a and 75b occurs.

  Furthermore, in the waste pyrolysis processing system of the present embodiment, a plurality of rows of pyrolysis processing systems for processing the processing object such as waste by thermal decomposition are installed, but at least the safety torch 17 is shared, so that the equipment cost This makes it possible to reduce operating costs. In this case, in order to realize the facility cost and the operation cost safely and most efficiently, in addition to the safety torch 17, the granulator 13 and the water treatment device 14 are shared, and other devices may be provided individually. Is possible.

1 is a block diagram showing an entire waste pyrolysis processing system according to one embodiment of the present invention. Sectional drawing of the part of the pyrolysis furnace and gas reformer in the waste pyrolysis processing system of the said embodiment. Sectional drawing of the part of the gas reformer and gas cooler in the waste pyrolysis processing system of the said embodiment. Sectional drawing of the part of the gas purification apparatus in the waste pyrolysis processing system of the said embodiment, an induction blower, and a water seal apparatus. Sectional drawing which shows the part of multiple systems gas reformer and the safety torch common to these in the waste thermal decomposition treatment system of the said embodiment. The block diagram of the control apparatus of the waste pyrolysis processing system of the said embodiment. Sectional drawing which shows another example of the part of the gas reformer of multiple systems in the waste thermal decomposition processing system of the said embodiment, and the safety torch common to these. .

Explanation of symbols

3 Pyrolysis furnace 4, 4a, 4b Gas reformer 5, 5a, 5b Gas cooler 6, 6a, 6b Gas purification device 7, 7a, 7b Induction blower 8, 8a, 8b Water seal device 9, 9a, 9b Supply Blower 13 Granulator 14 Water treatment device 17 Safety torch 18 Inert gas injection valve 19 Inert gas injection valve 20 Gas gate valve 20a, 20b Gas gate valve 27 Pyrolysis burner 47 Bag filter 56 In-furnace screw 71a, 71b Tunnel portion 72a, 72b Plug 73a, 73b Granular body 74a, 74b Lifting mechanism 75a, 75b Gas piping 76 Exhaust tower 77 Combustion air blower 78 Pilot burner 79a, 79b Hot gas transfer blower 80 Pressure sensor 81 Main valve 82 Sub valve 91 Controller 92 Inverter

Claims (6)

The object to be treated such as crushed waste pyrolysis furnace for pyrolysis,
A waste supply device for supplying a material to be processed such as the crushed waste to the pyrolysis furnace;
A gas reformer that accepts an organic polymer gas generated by thermal decomposition of the object to be processed in the pyrolysis furnace, reforms it into a low-molecular combustible gas by high-temperature gas reforming treatment, and discharges it. When,
A gas cooler that receives and cools the combustible gas discharged from the gas reformer, and discharges the combustible gas;
A gas purification device that receives the flammable gas discharged from the gas cooler, purifies and removes impurities, and discharges the purified flammable gas;
An induction blower for keeping the pyrolysis furnace, the gas reformer, the gas cooler, and the gas purification device in a negative pressure state and attracting gas into each of them,
In a waste pyrolysis system comprising a supply blower for supplying the purified combustible gas attracted by the induction blower to a gas user through a supply pipe ,
And emergency stop means for said waste supply device is stopped in an emergency failure or abnormal process such devices configured to stop the introduction of waste into the pyrolysis furnace, stopping the attractant blower supply blower ,
A waste pyrolysis processing system comprising: the gas reformer and a gas venting means for venting the pyrolysis gas continuously generated from the pyrolysis furnace when the emergency stop means is operated.   2. The waste pyrolysis system according to claim 1, wherein the gas venting means is a gas gate valve composed of a stopper that can withstand a high temperature of the pyrolysis gas and a sealing granule.   An emergency inert gas injection means for injecting an inert gas into the upstream part of the pyrolysis furnace and the downstream part of the gas cooler, which operates simultaneously with the gas venting means when the emergency stop means is operated, is provided. The waste thermal decomposition treatment system according to claim 1 or 2. The gas purification apparatus includes a bag filter that scrapes carbon dust from the pyrolysis gas , and the waste pyrolysis processing system operates simultaneously with the gas venting means to bypass the pyrolysis gas flowing through the bag filter. The waste pyrolysis system according to any one of claims 1 to 3, further comprising bypass means for switching to a line. It said venting means and operated simultaneously, waste pyrolytic processing system according to any of claims 1 to 4, characterized in that example Bei the gas cooler stop means to stop the Susuharai of the gas cooler. Furnace pressure measuring means for measuring the furnace pressure of the pyrolysis furnace;
3. The degassing control unit according to claim 2, further comprising a degassing control unit configured to degas while adjusting a valve opening degree of the gas gate valve and maintaining a constant negative pressure in the pyrolysis furnace. Waste pyrolysis treatment system .

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