Patent ID: 12196417

DETAILED DESCRIPTION

FIG.1shows a combustible treatment apparatus according to an embodiment of the present invention, and the treatment apparatus1is provided with a hopper2for receiving a combustible C, a mixer3for gasifying the combustible C supplied from the hopper2by mixing the combustible C with a preheated raw material R2 of 600° C. or higher and 900° C. or lower, which is drawn from a cyclone11B in the second stage from the bottom of a preheater11of a cement burning device10, and a feeder5for suppling the gasified combustible C and the preheated raw material R2 (including a non-gasified combustible C, hereinafter referred to as “mixed raw material M”) to a region from an inlet end13aof a cement kiln13to a calciner12of the cement burning device10. Although two cyclones11B are drawn inFIG.1for the convenience of explanation, they are the same.

The combustible C to be treated includes a combustible waste such as waste plastic, waste tires, rice husk, wood shavings, PKS, RDF and sludge, and a fossil fuel such as coal and coke.

The mixer3is a pug mill or the like in which many blades3bare attached to a horizontal shaft3a, and rotating the horizontal shaft3aallows the blades3bto be rotated also, and mixes the combustible C with the preheated raw material R2 to gasify the combustible C.

A water spray device (not shown) is provided above the mixer3, and sprays water into the mixer3(moisture W is supplied) to carry out water gas shift reaction. The mixer3is provided with a hood3cin order to prevent scattering dust from increasing due to the sudden generation of water vapor.

A shut damper4is installed below the mixer3, and introducing a mixed raw material M to the region from the inlet end13aof the cement kiln13to the calciner12of the cement burning device10via the feeder5while maintaining airtightness. Further, an exhaust duct6for discharging the gasified gas G is provided, and the gas G discharged from the exhaust duct6merges with the mixed raw material M below the shut damper4, and is introduced into the region from the inlet end13aof the cement kiln13to the calciner12of the cement burning device10via the feeder5. As the feeder5, a chute, a duct or a transporter is used.

The cement burning device10to which the processing device1is attached is provided with the preheater11for preheating the cement raw material R1, the calciner12for calcining the preheated raw material R2 from the cyclone11B in the second stage from the bottom of the preheater11, the cement kiln13for firing the raw material R3 from the lowermost cyclone11A of the preheater11with the fuel F blown from the main burner15, a clinker cooler14for cooling cement clinker fired in the cement kiln13, and the like, and these components are identical to the conventional ones. It is preferable that at the supply position of the mixed raw material M with the feeder5, the powder or granular material dispersion device of Japan Patent No. 6396433 by the present applicant is installed, and the gasified combustible C and the preheated powdery raw material are effectively dispersed into the gas.

Next, a method for treating combustible with the treatment device1will be described with reference toFIG.1.

During the operation of the cement burning device10, the combustible C received in the hopper2is supplied to the mixer3, and a part of the preheated raw material R2 discharged from the cyclone11B of the preheater11is drawn, and the drawn raw material R2 is introduced into the mixer3. The preheated raw material R2 that is not drawn is decarbonated in the calciner5and the lowermost cyclone11A as usual, and then fired in the cement kiln13to generate cement clinker.

In the mixer3, the combustible C and the preheated raw material R2 are conveyed while being mixed and stirred, and the combustible C is heated and gasified with the separated preheated raw material R2, and water is sprayed from the water spray device to carry out water gas shift reaction. Mixing the combustible C with the preheated raw material R2 avoids adhesion trouble due to tar generated during gasification. Further, acid gas generated from the combustible C can be fixed to the preheated raw material R2. In addition, since combustion time can be shortened through gasification, it can be effectively burned even in the conventional calciner12for coal combustion, and the amount of coal used and the amount of CO generated can be reduced.

The mixing ratio of the combustible C and the preheated raw material R2 is not particularly limited, but when the combustible C adheres to the inside of the mixer3or the transport path, the mixing ratio of the preheated raw material R2 is increased. Further, when treating waste plastic or the like, it is preferable to crush it to approximately 200 mm or less in advance in the front stage of the mixer3. Further, it is preferable that the residence time of the combustible C in the mixer3is 5 to 15 minutes, the rotation speed of the horizontal axis3aof the mixer3is variable, and the residence time can be adjusted.

Further, since the mixer3is sealed with water vapor without introducing oxygen, there is no danger of explosion, and a reducing agent H2 is generated though water gas shift reaction, and since Fe2O3 in the preheated raw material R2 is also reduced to FeO, the amount of reducing agent increases dramatically.

The mixed raw material M discharged from the mixer3is supplied to the region from the inlet end13aof the cement kiln13to the calciner12of the cement burning device10with the feeder5via the shut damper4. As described above, since the amount of reducing agent is dramatically increased, NOx in the cement kiln combustion gas can be effectively reduced. Further, among the mixed raw materials M, the non-gasified combustible C is used as a fuel substitute in the calciner12, and the preheated raw material R2 drawn is decarbonated in the calciner12and the lowermost cyclone11A and is fired in the cement kiln13to produce cement clinker.

In the above embodiment, the preheated raw material R2 is drawn from the cyclone11B of the preheater11, but it may be drawn from other parts if the temperature of the cement raw material to be drawn is 600° C. or more and 900° C. or less.

Further, a water spray device is provided and water is sprayed into the mixer3to carry out water gas shift reaction in the above embodiment. Without spraying water, simply mixing the combustible C with the drawn preheated raw material R2 for gasification avoids adhesion trouble due to tar generated during gasification, and there are effects such as shortening combustion time by gasification, and the combustible C can be effectively used and the NOx concentration in the cement kiln exhaust gas can be reduced while maintaining the stable operations of the treatment apparatus1and the cement burning device10.

The configuration of the mixer3is not limited to the above, and if the combustible C can be mixed with the drawn preheated raw material R2 and gasified, and if water is further added to carry out water gas shift reaction, it can also be adopted in other types of devices.

DESCRIPTION OF THE REFERENCE NUMERALS

1combustible treatment apparatus2hopper3mixer4shut damper5feeder6exhaust gas duct10cement burning device11preheater12calciner13cement kiln14clinker cooler15main burner