JP2005074333A - Exhaust gas treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment apparatus based on a dry treatment of the burning exhaust gas of synthetic resin products and ensuring control of the emission of dioxins, dust and smelling ingredients below specified values. <P>SOLUTION: The apparatus is for treatment of 200°C or lower exhaust gas emitted from the combustion chamber burning synthetic resin products and has a treating powder supplying section 22 spraying and supplying a mixed powder of activated carbon and slaked lime into the gas, a bag filter 24 removing powder from the gas and an activated carbon adsorption section which consists of an activated carbon layer 27a for neutrality arranged in the first half and composed of ordinary carbon and an activated carbon layer 27b for acid arranged in the second half and composed of a carbon adsorbing acidic gases and causes the gas to pass through its inside so as to remove smelling ingredients through adsorption, arranged in this order along with the exhaust gas duct 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust gas treatment device, and more particularly to an exhaust gas treatment device that treats exhaust gas discharged from a combustion chamber that burns a synthetic resin product in a dry manner.

  Conventionally, as an exhaust gas treatment device that removes harmful substances such as dioxins contained in incineration exhaust gas from municipal waste incinerators, etc. (1) Injecting slaked lime mixed with activated carbon into the exhaust gas and adsorbing dioxin etc. on the activated carbon (2) Dust collected by bag filter, (2) Dust collected by bag filter, passed through activated charcoal packed tower to remove dioxin, etc., (3) Bug Dust collected by a filter and then passed through a desulfurization catalyst packed tower to oxidatively decompose dioxin and the like with the desulfurization catalyst. After blowing the agent, dust is collected with a bag filter, and then passed through a denitration catalyst packed tower to make nitrogen oxides harmless by denitration reaction. Are (e.g., see Patent Document 1.).

Further, after exhaust gas from the waste treatment furnace is cooled to 160 to 170 ° C., dust is collected by a bag filter device, and then harmful components such as nitrogen oxides are removed by an exhaust gas cleaning device, etc. As a bag filter device applied to, so that corrosive gas does not condense, and even if ignitable auxiliary agents such as activated carbon are mixed in the exhaust gas to remove dioxin, it does not ignite In addition, there is also known one provided with heating means for heating the hopper without locally generating a high-temperature part (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-249160 JP 2001-347120 A

  By the way, when a synthetic resin product made of PP, ABS resin or the like is normally incinerated, it is particularly important that the exhaust gas easily contains dioxin and has a bad smell because many odorous components are included. It becomes a problem. Therefore, in order to suppress the generation amount of dioxin, it is conceivable to incinerate at a low temperature. Even in that case, even if the exhaust gas treatment apparatus having the configuration as disclosed in Patent Document 1 is used, the dioxin or There is a problem that it is difficult to reduce the amount of dust emission to a specified value or less and to reliably reduce the odor components such as sulfur oxide and hydrogen chloride to a specified value or less.

  As a means for reliably removing odorous components in exhaust gas, it has been conventionally known to use a wet scrubber, but in the case of a wet type, a large amount of wastewater treatment is required. There is a problem that it is not preferable.

  In view of the above-described conventional problems, an object of the present invention is to realize an exhaust gas treatment capable of reliably removing dioxins and odor components contained in a combustion exhaust gas of a synthetic resin product by a dry treatment.

  In order to solve the above problems, an exhaust gas treatment apparatus of the present invention is a treatment apparatus for exhaust gas of 200 ° C. or less discharged from a combustion chamber that burns a synthetic resin product, and is disposed in exhaust gas along an exhaust gas discharge passage. A treatment powder supply unit that sprays and supplies mixed powder of activated carbon and slaked lime, a bag filter device that removes powder in exhaust gas, and an activated carbon adsorption unit that adsorbs and removes odorous components through exhaust gas inside are arranged in this order. is there.

  According to this configuration, the activated carbon powder sprayed into the exhaust gas adsorbs dioxin and the acid gas in the exhaust gas reacts with the slaked lime powder to be neutralized, and these mixed powders are removed together with dust with a bag filter device. Dioxin and acid gas can be removed from the exhaust gas, and the odorous components remaining in the exhaust gas can be reliably adsorbed and removed by passing the exhaust gas through the activated carbon adsorption part, so use a wet scrubber that requires wastewater treatment. In addition, the emission amount of dioxin and dust can be reduced below the specified value, and various odor components such as sulfur oxide and hydrogen chloride can be reliably reduced below the specified value.

  In addition, if a line mixer is installed in the discharge passage immediately after the treated powder supply unit, the entire exhaust gas can be brought into contact with the treated powder evenly and repeatedly, so that adsorption of dioxins in the exhaust gas and neutralization of acid gas are possible. Can be performed reliably.

  In addition, when the activated carbon adsorbing part is configured with a neutral activated carbon layer in the former stage and an acidic activated carbon layer in the latter stage, after adsorbing fine particles such as fine dust remaining in the exhaust gas in the former stage, it smells in the latter stage. It is possible to adsorb and remove acidic fine particles as a component.

  Further, if a heat exchanger for cooling the exhaust gas is disposed between the bag filter device and the activated carbon adsorption unit, the exhaust gas temperature can be cooled to, for example, about 40 ° C., and the adsorption action in the activated carbon adsorption unit can be efficiently performed. It can be performed and the exhaust gas discharge temperature can be lowered to prevent white smoke.

  Also, an odor sensor is provided at the outlet of the activated carbon adsorption unit, and the exhaust gas discharged from the activated carbon adsorption unit is either discharged outside or returned to the inlet of the treated powder supply unit according to the detection result of the odor sensor. When the flow path switching device for switching to is provided, the exhaust gas discharged to the outside can be surely free from odor.

  According to the exhaust gas treatment apparatus of the present invention, exhaust gas produced by burning a synthetic resin product at a low temperature is subjected to dry treatment that does not require wastewater treatment, and the amount of dust and dioxin emission is reduced to a specified value or less, and various odor components are also reliably obtained. It can be discharged below the specified value.

  Hereinafter, an embodiment in which the exhaust gas treatment apparatus of the present invention is applied to a synthetic resin product combustion experiment apparatus for office equipment will be described with reference to FIGS.

  1, 3, and 4, 1 is a combustion chamber for burning a combustion object 2 made of a synthetic resin product for office equipment, and a combustion table 3 on which the combustion object 2 is placed and combusted is located at the center in the lower part. Is installed. As shown in FIG. 3, an observation window 4 made of heat-resistant glass is disposed on the side wall of the combustion chamber 1 in order to visually check the combustion state. An exhaust port 5 is provided at the center of the ceiling, and a grill opening 6 for introducing combustion air is provided at the lower end of the side wall. An outside air introduction port 8 is connected to the exhaust port 5 via an outside air introduction adjustment valve 7 in order to adjust the temperature of exhaust gas discharged outside by introduction of outside air.

  An outlet 9 and an inlet 10 for gas circulation are provided at an upper part and a lower part of one side wall of the combustion chamber 1, and the atmosphere in the combustion chamber 1 is drawn from the outlet 9 and passed through the bag filter device 11. Is removed, and the circulation fan 12 is pushed into the combustion chamber 1 from the inlet 10 to circulate the atmosphere in the combustion chamber 1 by removing soot so that the combustion chamber 1 is in a low oxygen concentration state. ing. Thereby, combustion of the combustion target object 2 is suppressed and the inside of the combustion chamber 1 is made not to become high temperature. Specifically, the ambient temperature in the vicinity of the exhaust port 5 at the top of the combustion chamber 1 is controlled to 200 ° C. or lower.

  A sprinkler 13 is disposed above the combustion chamber 1 so as to extinguish water when the atmospheric temperature in the combustion chamber 1 rises abnormally, and is connected to a fire extinguishing facility 15 via an open / close control valve 14. The opening / closing control valve 14 opens when the temperature detector 16 disposed in the vicinity of the exhaust port 5 and the temperature detected by the temperature detector 17 disposed between the outlet 9 and the bag filter device 11 are each equal to or higher than a predetermined temperature. It is configured.

The combustion chamber 1 is provided with an HCl meter 18 and a CO / O ₂ meter 19 for monitoring the HCl concentration of the internal atmosphere and the ratio of the CO concentration and the O ₂ concentration.

  An exhaust gas pipe 20 is connected to the exhaust port 5. As shown in FIGS. 2, 3, and 4, the exhaust gas pipe 20 includes a temperature detector 21 that detects the temperature of the exhaust gas, and activated carbon in the exhaust gas. Powder processing unit 22 for spraying mixed powder of slaked lime and slaked lime, a flow rate adjusting valve 23 for exhaust gas, a bag filter device 24 for removing powder in the exhaust gas, and a heat exchanger for cooling the exhaust gas by heat exchange with the outside air 25, an exhaust fan 26, and an activated carbon adsorbing portion 27 for adsorbing and removing odorous components through exhaust gas inside are arranged in this order.

  According to the temperature of the exhaust gas passing through the exhaust gas pipe line 20 detected by the temperature detector 21, the outside air introduction adjustment valve 7, the flow rate adjustment valve 23, and the blower fan 25b of the heat exchanger 25 described later are controlled. It is configured.

  The treatment powder supply unit 22 includes a storage tank 22a containing a mixed powder obtained by mixing activated carbon and slaked lime powder at 50:50, a pressure feed fan 22b, a treatment powder supply port provided in the exhaust gas pipeline 20, and a pressure feed fan 22b. In addition, the mixed powder is formed by a transport pipe 22c connected to the discharge port of the storage tank 22a in the middle, and is put on an air flow that is pumped from the pressure feed fan 22b through the transport pipe 22c into the exhaust gas pipe 20. Are pneumatically conveyed and sprayed into the exhaust gas pipe 20.

  The bag filter device 24 is configured to separate and recover the soot in the exhaust gas and the powder supplied by spraying with the bag filter 24b accommodated in the hopper portion 24a, and the compressed air supplied from the compressor 28 to the bag filter. 24b is provided with a backwashing mechanism 24c that jets in a pulse shape in the direction opposite to the exhaust gas flow direction, backwashes the bag filter 24b, and drops and recovers the bag filter 24b into the hopper 24a. The bag filter device 11 similarly includes a hopper portion 11a, a bag filter 11b, and a backwash mechanism 11c.

  The heat exchanger 25 includes a heat exchange unit 25a, a blower fan 25b that blows outside air for heat exchange to the heat exchange unit 25a, a filter 25c that removes dust in the outside air and supplies the dust to the blower fan 25b, and a blower fan An inverter control unit 25d of 25b is provided, and a detection signal of the temperature detector 21 is input to the inverter control unit 25d.

  The activated carbon adsorbing unit 27 is a fixed bed type filled with activated carbon such as powder, crushed charcoal, granular (pellet), etc., and is composed of a neutral activated carbon layer 27a made of preceding ordinary charcoal and a subsequent acidic gas adsorbing charcoal. An acidic activated carbon layer 27b, and configured to adsorb and remove acidic fine particles, which are odorous components remaining in the exhaust gas. And the exhaust gas which passed this activated carbon adsorption part 27 is discharge | released in air | atmosphere.

  2, an odor sensor 29 is provided at the outlet of the activated carbon adsorption unit 27, and a flow path switching device 30 is provided in front of the exhaust gas discharge port. When the odor component more than a predetermined amount remains, the flow path switching device 30 is operated, the exhaust gas is recirculated to the position before the processing powder supply unit 22 through the reflux line 31, and the process is repeated again. Also good.

  Further, by disposing the line mixer 32 in the vicinity of the outlet of the treated powder supply unit 22, the activated carbon and the slaked lime are evenly dispersed in the exhaust gas, and the activated carbon and the slaked lime are effectively brought into contact with the entire exhaust gas. It is preferable to ensure that the adsorption of dioxin and the neutralization reaction of the acid gas are performed.

  Next, the operation will be described. A combustion object 2 made of a synthetic resin product is placed on the combustion table 3 and ignited to start combustion. At that time, the exhaust fan 26 does not operate at the initial stage of combustion, and only the circulation fan 12 is operated without exhausting from the exhaust port 5 and the atmosphere in the combustion chamber 1 is circulated. Let As a result, a large amount of soot is generated, but the generated soot is removed by the bag filter device 11 while the exhaust gas is circulated. Further, the temperature of the circulated exhaust gas is detected by the temperature detector 17, and the operation of the circulation fan 12 is controlled according to the temperature, thereby maintaining natural combustion at a relatively low temperature.

Further, when the combustion chamber 1 is in an excessive combustion state and the ambient temperature becomes abnormally high, and the temperature detected by the temperature detector 16 near the exhaust port 5 exceeds 200 ° C., the opening / closing control valve 14 is opened. Then, fire extinguishing water is supplied from the fire extinguishing equipment 15 to the sprinkler 13, and water is sprayed to extinguish the fire. Thereby, also in the combustion chamber 1 which has the observation window 4 which consists of glass windows, a combustion experiment can be performed safely. Further, since the atmosphere in the combustion chamber 1 is monitored by the HCl meter 18 and the CO / O ₂ meter 19, safety is ensured when an operator enters the combustion chamber 1.

When the low-temperature combustion state in the combustion chamber 1 is stabilized, the exhaust fan 26 is operated while maintaining the combustion state due to the circulation of the exhaust gas by the circulation fan 12, and the exhaust gas is sucked from the exhaust port 5 to the exhaust gas pipe 20. Discharge. The ratio of the exhaust gas flow rate to be circulated and the exhaust gas flow rate discharged from the exhaust port 5 is about circulation 7: discharge 3. The exhaust gas discharged from the exhaust port 5 has, for example, a maximum of about 40 m ³ N / min, and has a composition of SO ₂ of 60 ppm, HCl of 1053 ppm, dioxin of 10 ng-TEQ / m ³ N, and dust of 240 mg / m ^3. About N is contained. Further, the opening degree of the outside air introduction adjustment valve 7 is adjusted according to the temperature detected by the temperature detector 21 so that the gas temperature becomes 40 to 200 ° C., and the bag filter device is adjusted by adjusting the opening degree of the flow rate adjustment valve 23. 24 is prevented from overheating.

First, a mixed powder of activated carbon and slaked lime is sprayed and supplied to the exhaust gas discharged to the exhaust gas pipe 20 by the processing powder supply unit 22. The activated carbon and slaked lime come into contact with the exhaust gas, and dioxins are adsorbed and removed by the activated carbon powder, and the acidic gas reacts with the slaked lime to be neutralized and absorbed. The supply amount of the mixed powder exhibits a sufficient effect, for example, at about 100 to 300 mg / m ³ . Further, when the exhaust gas and the mixed powder are stirred and mixed immediately after the supply of the mixed powder, the opportunity of contact between the exhaust gas and these powders increases, and these actions are promoted and more effectively adsorbed. -Neutralization is performed.

  The activated carbon powder that has adsorbed dioxin and the slaked lime powder that has been neutralized with the acid gas are removed from the exhaust gas by the next bag filter device 24. Next, the exhaust gas is heat-exchanged with the outside air in the heat exchanger 25 and cooled from about 80 ° C. to about 40 ° C. Thus, by the exhaust gas temperature being cooled to 40 ° C. or less, the next adsorption at the activated carbon adsorption unit 27 is effectively performed.

Next, the exhaust gas is adsorbed with fine particles such as fine dust remaining in the exhaust gas in the neutral activated carbon layer 27a in the previous stage of the activated carbon adsorption unit 27, and further in the subsequent acidic activated carbon layer 27b, the odor component SO ₂ or Acidic fine particles such as HCl are reliably removed by adsorption. The exhaust gas thus purified and from which odorous components are removed is released into the atmosphere.

By the above treatment, for example, compared to the exhaust gas composition at the exhaust port 5, SO ₂ is reduced from 60 ppm to 40 ppm, HCl is reduced from 1053 ppm to 430 ppm, dioxin is changed from 10 ng-TEQ / m ³ N to 5 ng-TEQ / m to ³ N or less, it is possible to reduce the dust from 240 mg / m ³ N below 10 mg / m ³ N. Thus, without using a wet scrubber that requires wastewater treatment, it can be released into the atmosphere in a state that satisfies environmental standards.

  In the description of the above embodiment, an example in which the ratio of the activated carbon and slaked lime of the mixed powder supplied from the processing powder supply unit 22 is 50:50 is shown, but depending on the nature of the exhaust gas discharged from the exhaust port 5 of the combustion chamber 1 Needless to say, the composition of slaked lime may be increased when the concentration of acid gas is high, for example. Moreover, although the example which provided the activated carbon layer 27a for neutrality and the activated carbon layer 27b for acid in the activated carbon adsorption part 27 was shown, it cannot be overemphasized that the activated carbon layer for alkalis etc. may be provided.

  Moreover, although the said embodiment showed the example which applied the waste gas processing apparatus of this invention to the process of the waste gas discharged | emitted from the combustion chamber 1 in the combustion experiment apparatus of the combustion target object 2 which consists of synthetic resin products for office equipments, Of course, the exhaust gas treatment apparatus of the present invention can be applied to the exhaust gas treatment of a combustion treatment apparatus for various synthetic resin products, and the effect can be demonstrated without needing to be described again.

  The exhaust gas treatment apparatus according to the present invention makes it possible to reduce the emission of dioxin and dust to a specified value or less by dry processing, and to ensure that the various odorous components are also to a specified value or less. It can be treated and is useful for exhaust gas treatment in a combustion treatment apparatus for synthetic resin products.

1 is a schematic configuration diagram around a combustion chamber of a combustion experimental apparatus to which an embodiment of an exhaust gas treatment apparatus of the present invention is applied. It is a schematic block diagram of the waste gas processing part of the embodiment. FIG. 3 is a plan layout view of the combustion experiment apparatus of the same embodiment. It is an AA arrow elevational view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combustion chamber 20 Exhaust gas pipe 22 Process powder supply part 24 Bag filter apparatus 25 Heat exchanger 27 Activated carbon adsorption part 27a Activated carbon layer for neutral 27b Activated carbon layer for acid 29 Odor sensor 30 Flow path switching device 32 Line mixer

Claims (5)

An apparatus for treating exhaust gas of 200 ° C. or less exhausted from a combustion chamber that burns a synthetic resin product, wherein a treatment powder supply unit that sprays a mixed powder of activated carbon and slaked lime into the exhaust gas along an exhaust gas exhaust passage; An exhaust gas treatment apparatus comprising: a bag filter device that removes powder in exhaust gas; and an activated carbon adsorbing portion that adsorbs and removes odorous components through the exhaust gas in this order. The exhaust gas treatment apparatus according to claim 1, wherein a line mixer is disposed in the discharge passage immediately after the treated powder supply unit. 3. The exhaust gas treatment apparatus according to claim 1, wherein the activated carbon adsorbing portion is configured such that a neutral activated carbon layer is disposed in a preceding stage and an acidic activated carbon layer is disposed in a subsequent stage. The exhaust gas treatment apparatus according to claim 1, wherein a heat exchanger for cooling the exhaust gas is disposed between the bag filter device and the activated carbon adsorption part. An odor sensor is provided at the outlet of the activated carbon adsorption unit, and the exhaust gas discharged from the activated carbon adsorption unit is switched to either external discharge or reflux to the inlet of the treated powder supply unit according to the detection result of the odor sensor. The exhaust gas treatment apparatus according to claim 1, further comprising a flow path switching device.

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