JP2009066588A - Waste treatment apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make use of heat in a waste treatment apparatus by reusing waste as an energy source. <P>SOLUTION: A waste dried by a dryer is heated indirectly under a nearly oxygen deficient atmosphere in a kiln-type pyrolysis furnace to generate a pyrolysis gas which is decomposed under reducing atmosphere to lower hydrocarbons to produce a reformed gas. The reformed gas is desalted with a desalting agent, filtered with a bag filter and then subjected to washing by water and desulfurization with a desulfurizing agent to produce a purified gas which is used as a fuel of a gas engine to drive a power generator. The waste treating method comprises the above steps. The above reducing reformer gas produced under reducing atmosphere is supplied to a boiler to generate steam which is supplied to an air preheater to heat air. A fuel gas produced by mixing the heated air and the above purified gas is burned in a furnace to produce a high-temperature combustion gas. This combustion gas is mixed with an exhaust gas from the above gas engine to make a gas mixture of a specified temperature which is supplied to the above kiln-type pyrolysis furnace for indirect heating of a waste. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a waste treatment apparatus, and more particularly, a high-temperature exhaust gas from a generator in a waste treatment apparatus is used in a waste pyrolysis apparatus, and further used in a waste drying apparatus, The present invention relates to an apparatus for effective use.

  Conventionally, general waste discarded from households and industrial waste discarded from factories, etc. have been incinerated or landfilled in incinerators. It has become.

Therefore, in recent years, it is possible to batch treat waste containing combustible waste, non-combustible waste, metal, etc., such as general waste and industrial waste. Furthermore, waste is made harmless, and resources such as metals are recovered and recycled. A waste processing apparatus has been proposed (for example, Patent Document 1).
JP 2000-202419 A

  The waste treatment apparatus comprises: pyrolysis means for thermally decomposing waste to generate a combustible gas; gas reforming means for decomposing the combustible gas into lower hydrocarbons; The gas engine generator is driven by using the purified gas obtained through the gas cleaning / purification means for removing water and acid gas as fuel, and the thermal decomposition means is heated by the combustion heat of the fuel introduced from the outside. Alternatively, it is heated by the combustion heat obtained by burning a part of the purified gas.

  However, the apparatus has a problem in that the heat necessary for thermally decomposing waste is covered by the combustion heat obtained by burning an external fuel such as heavy oil, resulting in a large energy loss. In addition, there is a problem that the energy loss is large even when the combustion heat of the fuel gas is used.

  An object of the present invention is to provide a waste treatment apparatus that can effectively use thermal energy.

In order to achieve the above object, the waste disposal apparatus according to the present invention provides:
1) Waste drying process, pyrolysis process to generate waste gas by indirectly heating waste with almost no air, and cracking the pyrolysis gas into lower hydrocarbons in a reducing atmosphere A reforming step for producing a gas, a purification step for producing a purified gas by desalting, filtering and desulfurizing the reformed gas, and a power generation step for using the purified gas as a fuel for a gas engine that drives a generator. In the waste disposal method,
The reformed gas is supplied to a boiler to generate water vapor, the water vapor is supplied to an air preheater to heat the air to generate heated air, and the heated air and the purified gas are mixed to form a fuel gas The fuel gas is burned in a heating furnace, and the steam containing the odor generated in the drying process introduced into the heating furnace is heated to deodorize, and the high-temperature combustion exhaust gas exhausted from the heating furnace and the gas The waste gas is indirectly heated by supplying the mixed gas mixed with the exhaust gas of the engine to the thermal decomposition step.
2) The mixed gas is used as a heat source for a pyrolysis process in which waste is pyrolyzed, and the mixed gas used as a heat source in the pyrolysis process is used as a heat source in a drying process in which waste is dried. It is said.

In addition, the waste treatment apparatus according to the present invention is
3) A dryer that dries waste, a pyrolysis furnace that indirectly heats the waste dried by this dryer to generate pyrolysis gas in a state where the air is almost cut off, and a reducing atmosphere for the pyrolysis gas A reformed gas furnace for generating a reformed gas by decomposing it into lower hydrocarbons, a filtration device supplied with a desalting agent for desalting the reformed gas, and a desalted gas filtered by the filtration device In a waste treatment apparatus having a desulfurization apparatus for desulfurizing and producing a purified gas, a gas engine using the purified gas as a fuel, and a generator driven by the gas engine, the reformed gas is combusted to produce steam. Generated by the boiler, an air preheater that heats the air with water vapor generated by the boiler, and a fuel gas that is a mixture of the heated air generated by the air preheater and the purified gas, and is generated by the dryer Odor Pyrolysis that heats waste by indirect heating using a mixed gas that is a mixture of high-temperature combustion exhaust gas exhausted from this heating furnace and the exhaust gas of the gas engine. And a furnace.
4) The mixed gas is used as a heat source for a pyrolysis furnace in which waste is pyrolyzed, and the mixed gas used as the heat source in the pyrolysis furnace is used as a heat source for a dryer in which waste is dried. It is said.

(Multi-stage use of heat)
The waste treatment apparatus according to the present invention generates steam by supplying heat of the high-temperature reformed gas reformed in the reforming furnace, and heats the air introduced into the air preheater by the steam. Since the heated air and the purified gas are mixed to form a fuel gas and burned in a combustor using a high-temperature fuel gas, energy efficiency is good. In addition, a heat source for indirect heating of the kiln pyrolysis furnace can be easily obtained by supplying the combustion exhaust gas of the combustor to the exhaust gas of the gas engine.

  In addition, steam is generated by the heat of the high-temperature reformed gas, the air supplied to the combustor is heated by the steam so that efficient combustion can be performed, and the reformed gas that has generated steam is Since the temperature is reduced to such an extent that it can be filtered with a bag filter, the heat energy of the reformed gas can be effectively used without wasting it.

  Furthermore, steam containing deodorized odor from the dryer is heated and deodorized with a combustor, and the waste of the kiln type gasifier is indirectly heated with a mixed gas in which the exhaust gas of the combustor is mixed with the exhaust gas of the gas engine. In addition, the mixed gas after the indirect heating is used as a heat source for drying the waste of the dryer, and efficient use of thermal energy can be achieved by utilizing heat in multiple stages.

  Hereinafter, a waste treatment apparatus according to the present invention will be illustrated and described. The temperature condition shown in the present embodiment is an example and is appropriately changed depending on the design.

Example 1
As shown in FIG. 1, the waste treatment apparatus according to the present invention is a waste such as general waste or industrial waste, which is crushed to a predetermined size by a crusher A and supplied to a dryer B. Water in the waste is removed by indirect heating by the exhaust gas from the heating furnace R and gas engine P used in the rotary kiln C supplied to the dryer B.

  The waste material dried by the dryer B is supplied to the kiln-type cracking furnace C at a temperature of about 70 to 90 ° C. The waste is indirectly heated by the high-temperature exhaust gas (500 to 580 ° C.) from the heating furnace R and the gas engine P in the decomposition furnace C in an almost oxygen-free atmosphere to become about 430 to 500 ° C. It is decomposed into a certain pyrolysis gas g1 and a pyrolysis residue which is a non-volatile component.

  The pyrolysis gas g1 is 430 to 500 ° C., is exhausted from above the separation device D, and is introduced into the gas reforming furnace E through the pipe 12. The gas reforming furnace E has a reducing atmosphere in which water vapor w1 and oxygen are introduced. In the gas reforming furnace E, a part of the pyrolysis gas g1 is burned and becomes about 1000 to 1200 ° C. A reformed gas g2 is produced in which tar and soot contained in the pyrolysis gas g1 are decomposed into lower hydrocarbons and hydrogen.

  In the present embodiment, the reformed gas g2 is supplied to the boiler F1 at a high temperature of 1000 to 1200 ° C., and steam is generated in the boiler F1 to heat the air preheater F2, which will be described later. The air supplied to the combustor R is heated. The reformed gas g2 reduced in temperature by the boiler F1 becomes 200 to 400 ° C. and is introduced into the bag filter J to which a powdery desalting agent is supplied so that hydrogen chloride, soot and the like are removed. . The desalting agent is a “Solticle” sold by the applicant, and is supplied to the bag filter J by pumping with purified gas g4. Further, the desalting agent contains sodium hydrogen carbonate powder, hydrophilic wet silica powder and hydrophobic metal soap powder, the content of the hydrophilic wet silica is 1 to 10 wt%, The content is 0.1 to 0.5 wt%.

  The hydrophilic wet silica is white carbon having an average particle size of 10 to 200 μm. The metal soap contains at least one of calcium stearate, magnesium stearate, and zinc stearate. In addition, finely powdered activated carbon can be added for the purpose of removing dioxins and heavy metals in the reformed gas g2.

  The desalted gas g3 filtered by the bag filter J is introduced into the gas washing tower K, the tar content is removed by washing with water, and then introduced into the gas washing tower M, where the hydrogen sulfide is removed by the desulfurizing agent and purified gas. g4 (clean gas) is obtained. The purified gas g4 is washed with water in the gas washing towers K and M and is about 40 to 60 ° C.

  The purified gas g4 is stored in the gas storage tank N, and a predetermined amount of the purified gas g4 is supplied to the gas engine P and the combustor R. Further, the storage tank N is set at a predetermined pressure by a compressor (not shown) so that the gas pressure does not fluctuate due to fluctuations in the amount of waste processed.

  The purified gas g4 supplied from the storage tank is used as fuel for the gas engine P, and the generator S is driven by the gas engine to generate power. Further, the purified gas g4 and the air a1 heated by the air preheater F2 are introduced into the combustor R and burned.

  The exhaust gas g5 of the gas engine P is about 350 to 430 ° C., and the combustion exhaust gas g6 of the combustor R is 700 ° C. or higher, preferably 800 ° C. or higher, for heating deodorization described later. The mixed gas g7 adjusted to 450 to 600 ° C. by adding the combustion exhaust gas g6 of the combustor R to the exhaust gas g5 of the gas engine P is introduced into the kiln pyrolysis furnace C as a heat medium for indirect heating of waste. ing.

  As shown in FIG. 3, the kiln-type pyrolysis furnace C is provided with a plurality of heat medium circulation pipes C3 extending in the axial direction of a cylindrical body C1 at predetermined intervals in the circumferential direction. The heat exchange efficiency is higher than either the direct heating method in which heated air is fed into the main body C1 or the indirect heating method in which heated air is fed into the side surface, and the waste inside the cylindrical body is It can be heated uniformly by stirring, and further, the efficiency of stirring the waste is improved, and the waste indirect heating medium can be sufficiently used at a temperature of about 500 to 600 ° C. .

  The exhaust gas g8 used to indirectly heat the waste of the kiln pyrolysis furnace C is supplied to the dryer B as a heat source for drying the waste of the dryer B. The exhaust gas g9 used as a heat source in the dryer B is discharged from the chimney U to the outside.

  The water vapor w generated from the waste of the dryer B is supplied to the combustor R and is deodorized by heating. From the viewpoint of this deodorizing, the combustor R is 700 ° C. or higher, preferably 800 ° C. or higher. It is preferable to drive.

  Next, utilization of heat in the waste treatment apparatus configured as described above will be described with reference to FIG.

  Means for detecting the temperature of the high temperature gas g7 to the supply pipe 3 for supplying a high temperature gas g7, which is a mixture of the exhaust gas g5 of the gas engine P and the combustion exhaust gas g6 of the combustor R, as a heat medium for indirect heating of the kiln pyrolysis furnace C. An adjustment valve v1 for adjusting the gas flow rate based on the temperature signal Y1 detected by the temperature detecting means T1 is provided in the supply pipe 19 that is provided with T1 and supplies the purified gas g4 to the combustor R.

  Therefore, the opening and closing of the regulating valve v1 is adjusted so that the temperature becomes about 500 to 600 ° C. by adding the combustor exhaust gas g6 of about 800 ° C. to the gas engine exhaust gas g5 of 350 to 430 ° C. When the temperature of the mixed gas g7 supplied to the kiln-type pyrolysis furnace C is higher than a predetermined temperature, the adjusting valve v1 is adjusted to the closed side, and when the temperature is lower than the predetermined temperature, the adjusting valve v1 is adjusted to the open side. . Then, the heat of the gas engine exhaust gas g5 and the combustor exhaust gas g6 can be effectively used for heating waste in the kiln pyrolysis furnace C without wasting. Moreover, since the water vapor generated from the waste of the dryer B is heated and deodorized by the combustor R, the deodorizing treatment step can be omitted.

  In addition, the introduction pipe 4 that introduces the temperature-reduced gas g8 that has been heated by indirectly heating the waste of the kiln-type pyrolysis furnace C to the dryer B, and the temperature of the temperature-reduced gas g8 that circulates in the introduction pipe 4 And a bypass passage i1 communicating with the supply pipe 3 for supplying the high-temperature gas to the kiln-type pyrolysis furnace C and the introduction pipe 4 for introducing the temperature-reduced gas g8 to the dryer B. The bypass path i1 is provided with an adjusting valve v2 for adjusting the gas flow rate according to the temperature signal detected by the temperature detecting means T3 of the temperature-reducing gas g8.

  Therefore, when the temperature of the temperature-reducing gas g8 is higher than the predetermined temperature, the regulating valve v2 of the bypass passage i1 is adjusted to the open side, and when the temperature is lower than the predetermined temperature, the temperature reducing gas 8 is adjusted to the closing side. The temperature is maintained at a predetermined temperature. That is, the temperature of the temperature-reducing gas g8 exhausted from the kiln-type pyrolysis furnace C can be maintained at a predetermined temperature, and heat can be used more efficiently. Further, the temperature-reduced gas g8 can be effectively used in the dryer B that heats the waste at a lower temperature than the kiln-type pyrolysis furnace C.

  Further, the bypass pipe i2 for supplying the gas engine exhaust gas is provided in the introduction pipe 4 and the temperature detecting means T3 is provided, and the adjustment valve v3 for adjusting the gas flow rate based on the temperature signal detected by the temperature detecting means T3 is bypassed. Provided on the road.

  By adjusting the regulating valve v3 provided in the bypass passage i2, the exhaust gas g5 of the gas engine P is introduced into the temperature-reducing gas g8, and the temperature is increased from 280 to 330 ° C. to about 350 to 400 ° C. Yes. Therefore, the temperature of the heat medium (mixed gas) whose temperature decreases sequentially can be increased without using heating means, and the heat energy of the gas engine exhaust gas g5 is effectively used.

  Furthermore, a bypass pipe i3 communicating with the introduction pipe 4 and the discharge pipe 5 that discharges the gas g9 that has become low temperature by heating the waste of the dryer B is provided, and the temperature detection provided in the discharge pipe 5 An adjustment valve v4 for adjusting the gas flow rate based on the temperature signal detected by the means T4 is provided in the bypass passage i3.

  Therefore, the temperature-reducing gas g8 can be introduced into the low-temperature gas g9 (mixed gas) exhausted from the chimney, and the temperature can be raised to a temperature satisfying the anti-whitening conditions (120 to 180 ° C, preferably 150 ° C) for exhaust The heating device for anti-whitening becomes unnecessary.

  According to the present embodiment, the heat of the pyrolysis gas generated in the kiln-type pyrolysis furnace is recovered by the boiler, and the generator is driven by operating the gas engine using the purified gas as fuel, and the thermal energy of the exhaust gas of this gas engine Is used as a heat source for the kiln-type pyrolysis furnace and the dryer, so that heat energy can be recovered efficiently and effectively used in the waste treatment apparatus.

  In addition, heat exchange efficiency is improved by adopting a kiln-type cracking furnace as a multi-tube type, and it is possible to operate at a lower temperature than the conventional heating method that blows hot air into the kiln body, so the energy required for the heat source Can be reduced.

  In addition, this invention is characterized by using a heat | fever stage, Comprising: The operating condition (temperature) shown in the said Example is an example, It is not limited to this.

  In this embodiment, steam and oxygen are supplied in the reforming furnace, but air can be supplied instead of oxygen.

  Further, the steam generator may be driven by the heat of the reformed gas to generate electric power, and the air preheater may be heated by exhaust heat from the generator.

(Example 2)
In the present embodiment, the fuel gas is obtained from the thermal decomposition residue. The same reference numerals as those in the first embodiment represent the same members, and the description thereof is omitted.

  The pyrolysis residue generated in the kiln pyrolysis furnace C is separated from the pyrolysis gas g1 from below the separator D, cooled to about room temperature by the cooler 30, and supplied to the separation device 36. The separation device 36 separates metals, heavy metals, and the like into carbides, the metals are recovered, and the carbides are ignited in a melting furnace 37 to about 1300 to 1500 ° C. to volatilize containing glassy slag and carbides. Separated into sex gases. This volatile gas is washed with water in the gas washing tower 38 to remove soot and the like, and after being cooled to 200 to 400 ° C. which is the reformed gas temperature at the outlet of the boiler F1, the reformed gas between the boiler F1 and the bag filter J. It is mixed with g2.

  According to this embodiment, the production amount of purified gas, which is a fuel for the gas engine, increases, so that higher thermal energy can be extracted. In addition, the amount of resources recovered increases.

1 is a schematic configuration diagram of a waste treatment apparatus according to the present invention. It is a figure which shows the multistage utilization of the heat | fever of the combustion gas of the waste processing apparatus which concerns on this invention. 1 is a schematic cross-sectional view of a kiln-type pyrolysis furnace of a waste treatment apparatus according to the present invention. It is the schematic which shows the other embodiment which concerns on this invention.

Explanation of symbols

A Crusher B Dryer C Rotary kiln (kiln type cracking furnace)
D Sorting machine E Reforming furnace F1 Boiler F2 Air preheater H Storage container H1 Fixed cut feeder J Bag filter K Gas cleaning tower M Desulfurization tower N Gas holder P Gas engine R Heating furnace S Generator v1, v2, v3, v4 Regulating valve t1, t2, t3, t4 Thermometers i1, i2, i3, i4 Bypass path g1 Pyrolysis gas g2 Reformed gas g3 Desalted gas g4 Refined gas g5 Gas engine exhaust gas g6 Heated gas g7 Mixed gas g8 Heated gas after passing through kiln g9 Heated gas after passing through the dryer a1 Preheated air w Water

Claims (4)

A waste drying process, a pyrolysis process in which the waste is indirectly heated with almost air cut off to generate pyrolysis gas, and the pyrolysis gas is decomposed into lower hydrocarbons in a reducing atmosphere to be reformed gas Waste having a reforming process for generating a gas, a purification process for generating a purified gas by desalting, filtering, and desulfurizing the reformed gas, and a power generation process using the purified gas as fuel for a gas engine that drives a generator In the processing method of
The reformed gas is supplied to a boiler to generate water vapor, the water vapor is supplied to an air preheater to heat the air to generate heated air, and the heated air and the purified gas are mixed to form a fuel gas The fuel gas is burned in a heating furnace, and the steam containing the odor generated in the drying process introduced into the heating furnace is heated to deodorize, and the high-temperature combustion exhaust gas exhausted from the heating furnace and the gas A waste treatment method, wherein a waste gas is indirectly heated by supplying a mixed gas mixed with engine exhaust gas to the thermal decomposition step.   The mixed gas is used as a heat source for a pyrolysis process in which waste is pyrolyzed, and the mixed gas used as a heat source in the pyrolysis process is used as a heat source in a drying process in which waste is dried. The waste disposal method according to claim 1. A dryer for drying the waste, a pyrolysis furnace for indirectly heating the waste dried by the dryer in a state where air is substantially cut off, and generating the pyrolysis gas; and the pyrolysis gas in a reducing atmosphere. A reformed gas furnace that generates reformed gas by decomposing into lower hydrocarbons, a filtration device that is supplied with a desalting agent for desalting the reformed gas, and desulfurizing the desalted gas filtered by the filtration device In a waste treatment apparatus having a desulfurization device to be purified gas, a gas engine using the purified gas as fuel, and a generator driven by the gas engine,
A boiler that burns the reformed gas to generate water vapor, an air preheater that heats air with the water vapor generated in the boiler, and a fuel gas that is a mixture of heated air generated by the air preheater and the purified gas A heat source is a mixed gas in which a high-temperature combustion exhaust gas exhausted from this heating furnace and a gas engine exhaust gas are mixed with a heating furnace that deodorizes by heating water vapor containing odor generated in the dryer A waste treatment apparatus comprising: a pyrolysis furnace that indirectly heats and decomposes waste.   The mixed gas is used as a heat source of a pyrolysis furnace in which waste is pyrolyzed, and the mixed gas used as the heat source of the pyrolysis furnace is used as a heat source of a dryer in which waste is dried. The waste processing apparatus according to claim 3.

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