JP2009079885A - Waste treatment device and treatment method for preferentially taking out steam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten preheating-drying time of inputting waste, to increase a generation quantity of hydrogen gas, in its turn, to restrain generation of dioxin being a toxic substance, by recovering steam from there, by arranging an exhaust gas hole in a furnace upper part of a reduction melting furnace. <P>SOLUTION: The exhaust gas hole is arranged in a furnace body upper part of the reduction melting furnace. The steam is taken in, and the taken-in steam generates the hydrogen gas by reduction reaction with coke of a sub-raw material by blowing in from a twyer of a furnace lower part, and is generated in larger quantities than a conventional method, and dries an input object in the furnace in a short period. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a gas riser pipe for sending reducing gas to the next process at the lower part of a reduction melting furnace for treating general waste and industrial waste, and an exhaust gas hole at the upper part of the furnace body to In addition to accelerating the drying of the upper part of the furnace main body by collecting it, the technique relates to a technique that is used for generating hydrogen gas by blowing the recovered water vapor from the tuyeres at the lower part of the furnace.

  In recent years, the amount of municipal solid waste, industrial waste, etc. (hereinafter referred to as waste) has increased, and most of this waste has been reduced by incineration, resulting in incineration ash as a residue. Reclaimed at the final disposal site. However, due to an increase in the amount of waste, there is a problem of shortage of final disposal sites.

As means for effectively dealing with this problem, there is a reduction melting furnace described in Patent Document 1 proposed by the applicant.
JP 2004-132655 A

  In the reduction melting furnace described in Patent Document 1, coke and limestone are charged from the charging port as a processing object such as waste and auxiliary materials, and the charged processing object and coke are accumulated in the furnace and packed. The air is supplied from the upper, middle and lower tuyere, and combustible components and coke in the waste melt in a reduced state. The generated gas rises in the melting furnace from the bottom of the furnace and preheats, dries, and pyrolyzes the waste. In this way, the waste, coke and limestone that have been input become water vapor until reaching the lower part of the furnace, the combustion components are thermally decomposed, and the solid matter is melted. The melt is taken out from the slag outlet. Further, a gas of 800 ° C. or higher such as combustion gas or exhaust gas generated when the object to be processed is melted is sent to a subsequent process through a gas recovery pipe, and can be used as thermal energy, gas resources, or the like.

  The reduction melting furnace described in Patent Document 1 has a structure in which a gas recovery pipe is provided at a position 3 m or more lower than the waste filling level so that reducing gas at 800 ° C. or higher can be recovered.

  In the case of the above method, when any one kind of gas is used in order to pass through the gas recovery pipe in a mixed state with water vapor, hydrogen gas, carbon monoxide gas or the like which can be generated by melting the waste Had to separate the mixed gas with a separator.

  In addition, the upper part of the furnace, especially the upper part of the waste filling level, is a preheating / drying zone for waste introduced from the top of the furnace, so the amount of water vapor is higher than the lower part of the furnace and preheating / drying takes time. Was an issue. Moreover, although hydrogen gas is produced | generated by the reductive reaction of water vapor | steam and coke, since water vapor | steam retains in the upper part, it is also a subject that the production amount is small.

  On the other hand, an exhaust gas hole is provided near the top of the furnace, and means for taking out the exhaust gas from the position is used. In the case of the above method, although water vapor is easily obtained, since the exhaust gas temperature at the furnace outlet is as low as about 200 to 300 ° C., there is a high possibility that dioxins which are harmful substances are generated.

  An object of the present invention is to provide an exhaust gas hole in the upper part of a reduction melting furnace as in Patent Document 1 and recover water vapor therefrom, thereby shortening the preheating / drying time of the input waste and generating hydrogen gas. It increases the amount and, in turn, suppresses the generation of the harmful substance dioxin.

In order to achieve the above object, the gist of the present invention is as follows.
(1) In a reduction melting furnace that treats general waste and industrial waste, a gas riser pipe is provided to send a reducing gas to the next process at least 3 m below the waste filling level, and a gas riser below the waste filling level. An exhaust gas hole for letting gas out of the furnace is provided at a higher position, and water vapor staying in the upper part of the furnace is taken in through the exhaust gas hole. A waste processing apparatus and a processing method for preferentially taking out water vapor for the purpose of generating hydrogen gas by the reduction reaction of the above and drying the input in the furnace in a short period of time.

(2) In the reduction melting furnace that treats general waste and industrial waste, the water vapor staying in the upper part of the furnace is taken in through the exhaust gas holes, and the taken-in water vapor is blown from the tuyeres at the lower part of the furnace and coke, which is a secondary raw material. The waste treatment apparatus and treatment method for preferentially extracting water vapor as described in (1), wherein hydrogen gas is generated by a reduction reaction and the charge in the furnace is dried in a short period of time.

  According to the present invention, the exhaust gas hole provided in the upper part of the furnace main body is provided, and by collecting the water vapor from the exhaust gas hole, the recovered water vapor is sent to the tuyere that feeds air into the furnace, and filled in the furnace. Hydrogen gas can be obtained by a reduction reaction with coke. Further, since the water vapor is discharged outside the furnace, the humidity in the upper part of the furnace is reduced, the preheating / drying of the waste introduced from the top of the furnace is accelerated, and the time required for the melting treatment of the waste can be shortened. Furthermore, dioxin contained in the water vapor can be decomposed by blowing water vapor obtained from the exhaust gas holes into the tuyere and reducing the gas at a high temperature.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view of a main body of a reduction melting furnace according to the present invention. FIG. 2 shows an example in which the steam recovered in FIG. 1 is blown into a tuyere provided in the lower part of the furnace. FIG. 3A shows an example in which a filter is provided in the exhaust gas hole, and FIG. 3B shows an example in which a separation device is provided in the exhaust gas hole. FIG. 4 shows an example in which the steam recovered in FIG. 1 is used for hot water or the like.

  In the reduction melting furnace 1, waste to be treated and a coke or limestone charge 2 as a secondary material are placed in a skip bucket, raised using a hoisting device, and the waste is placed in the furnace.

  The charge 2 forms a packed bed inside the furnace, and air is supplied from the upper, middle and lower tuyere, and the waste is melted and thermally decomposed in a reduced state with coke. The pyrolyzed gas rises toward the upper part of the furnace, and the input waste is warmed in the preheating / drying zone at the upper part of the furnace. And melted.

  Examples of the gas generated in the reductive melting furnace 1 include water vapor 4 generated during preheating and drying, and reducing gas 5 such as hydrogen gas and carbon monoxide gas generated by a reduction reaction with coke.

  Among the generated gases, the steam 4 is largely retained in the space near the waste input level 3 at the top of the reduction melting furnace 1. This is because the upper part of the furnace is a preheating / drying zone of the waste that has been charged, and heat is applied to the waste at this location, and the internal moisture is released as water vapor 4.

  The gas containing the water vapor 4 staying in the upper part of the reduction melting furnace 1 is led to the exhaust gas hole 6 provided at the waste filling level 3 or lower and above the position of the gas riser pipe and recovered. Since gas rises from bottom to top lighter than air, it is desirable that the installation angle be tilted upward with respect to the horizontal direction of the furnace.

  If the exhaust gas hole 6 is provided with a filter 10 that blocks dust as shown in FIG. 3A, water vapor without foreign matter can be obtained.

  Furthermore, as shown in FIG. 3B, high-purity water vapor can be obtained by providing a separation device 11 that selectively separates only the water vapor 4.

  The steam 4 discharged to the outside of the furnace passes through the exhaust gas pipe 8 and is sent together with the air to the tuyere 9 for sending the air provided in the lower part of the furnace into the furnace, and the steam and the coke filled in the furnace. Hydrogen gas is generated by the reduction reaction.

  Since the water vapor 4 has a low temperature of about 200 to 300 ° C., it may contain dioxins, but dioxins can be decomposed by blowing the water vapor 4 into the tuyere and generating hydrogen gas.

  Further, the recovered water vapor 4 may be further heated using the heating device 12 and used as a heat source for the hot water facility 13 or the like.

  Reducing gas 4 such as hydrogen gas and carbon monoxide gas generated by the reduction reaction between waste 2 and coke put into the furnace is sent to a gas riser pipe 7 for the next process such as a gas combustion chamber or a cooling tower. Sent.

  Since the concentration of hydrogen gas, which is a reducing gas, suddenly increases below 3 m from the waste filling level 3, it is desirable to provide a gas riser below this point. Therefore, the gas recovery pipe 7 is provided at least 3 m below the waste filling level 3 of the reduction melting furnace 1 and extends upward.

  By installing the gas recovery pipe 7 as described above, the temperature of the reducing gas 5 entering the gas recovery pipe 7 becomes 800 ° C. or higher, and there is no possibility of generating harmful substances such as dioxins.

  Waste was treated using a melting furnace according to the present invention and a conventional melting furnace. The melting furnace according to the present invention is provided with an exhaust gas hole 1.5 m below the waste filling level of the conventional melting furnace, and the recovered water vapor passes through the exhaust gas pipe from the exhaust gas hole, and the tuyeres at the bottom of the furnace Connected to the air and sent to the tuyere with air. Moreover, the treated waste is 2t / day of general waste.

  From Tables 1 and 2, by providing the exhaust gas holes 5 in the upper part of the furnace and collecting the water vapor 3, the amount of water vapor in the upper part of the furnace was reduced and the time required for drying the waste was shortened. In addition, the amount of hydrogen gas produced increased, which demonstrated a reduction in preheating and drying time and an increase in hydrogen gas production.

Schematic of a reduction melting furnace according to the present invention Example of blowing water vapor into the tuyere Example when a filter and separation device are provided in the exhaust gas hole Example when steam is sent to a heater and used for hot water

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reduction melting furnace 2 Waste 3 Waste filling level 4 Water vapor 5 Reducing gas 6 Exhaust gas hole 7 Gas riser pipe 8 Exhaust gas pipe 9 Tuyere 10 Filter 11 Separation device 12 Heating device 13 Hot water facility etc.

Claims (2)

  In a reduction melting furnace that treats general waste and industrial waste, a gas riser pipe is provided to send the reducing gas to the next process at least 3 m below the waste filling level, and above the gas filling pipe below the waste filling level. A waste processing apparatus and a processing method for preferentially extracting water vapor provided with an exhaust gas hole for discharging gas out of the furnace at a position.   In the reduction melting furnace that treats general waste and industrial waste, gas that stays in the upper part of the furnace, especially water vapor, is taken in through the exhaust gas holes, and the taken-in water vapor is blown from the tuyeres at the lower part of the furnace and reduced to coke, which is an auxiliary material. The waste processing apparatus and processing method for preferentially extracting water vapor according to claim 1, wherein hydrogen gas is generated by the reaction and the input in the furnace is dried in a short period of time.

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