JPH11286684A - Continuous carbonization furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a furnace for conducting continuous carbonization treatment of high water content organic wastes such as ciehydrated sludge of sewage water, human wastes or the like, pulp sludge and food sludge at a low cost. SOLUTION: A continuous carbonization furnace comprises a metallic retort 8 provided almost horizontally through a furnace body 1 and is rotationally driven; retort 8 having partition walls 12 which divide retort 8 into a drying zone 15, a dry distillation carbonization zone 16 and an activation zone 17 in the direction of the outlet from the inlet of furnace body 1 and allow substances to be treated to flow within retort 8 but shut off a gas flow; dry distillation carbonization zone 16 and activation zone 17 of retort 8 having exhaust pipes 19 for releasing a gas within retort 8 into furnace body 1; burners 26 provided at the positions corresponding to dry distillation carbonization zone 16 and activation zone 17 in furnace body 1 to heat drying zone 15 with the combustion gas flowing in from the positions corresponding to dry distillation carbonization zone 16 and activation zone 17 from the outside of retort 8; and a pipe for supplying the gas generated within drying zone 15 to activation zone 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace for continuously carbonizing high-moisture organic waste such as dewatered sludge such as sewage and human waste, pulp sludge and food sludge at low cost.

[0002]

2. Description of the Related Art Dry carbonization of high-moisture organic waste requires drying as a pretreatment. First, an object to be treated is put into a drum provided with blades therein and stirred by rotating. In addition, heat was exchanged with the exhaust gas from a carbonization furnace provided separately, and the air heated by a burner was blown in to dry. However, since the exhaust gas generated by drying had an odor, 800 Heated above ℃ and released into the atmosphere.

[0003]

As described above, in an apparatus in which the drying furnace is provided separately from the carbonization furnace, when the exhaust gas from the carbonization furnace is used as a heat source for drying, the heat is released by the heat release during the transfer of the exhaust gas. There is a problem that the loss is large and the running cost is high because a large amount of fuel is required to heat the exhaust gas in the deodorizing furnace.

[0004]

Means for Solving the Problems, Functions and Effects As means for solving such problems, the invention according to claim 1 is directed to a metal retort which is driven to rotate substantially through a furnace body substantially horizontally. A drying zone from the inlet to the outlet by a partition wall that allows the flow of the workpiece and blocks the flow of gas,
The retort is divided into a carbonization zone and an activation zone, and an exhaust pipe for releasing gas in the retort into the furnace is provided in the carbonization zone and the activation zone of the retort, and a burner is provided at a position corresponding to the carbonization zone and the activation zone of the furnace body. Is established,
The drying zone is heated from the outside of the retort by a combustion gas flowing from a position corresponding to the dry distillation carbonization zone and the activation zone of the furnace body, and a pipe for supplying gas generated in the drying zone to the activation zone is provided. It is provided.

[0005] In the present specification, drying refers to removing water adhering to an object to be treated or water contained in pores of the object to be treated by heating and air. Dry carbonization refers to reduction of an organic object to be treated. Heating in an atmosphere to thermally decompose and volatilize volatiles (carbonized gas) to leave carbon and ash, and activation is to remain in the pores of the porous solid that has been carbonized and ashed by dry carbonization. The tar content is discharged by steam to increase the number of pores, and a small amount of dry distillation gas is generated.

According to the first aspect of the present invention, a drying zone, a carbonization zone and an activation zone are formed from an inlet to an outlet by a partition wall which permits the flow of an object to be processed and blocks the flow of gas in a metal retort. Since the zones are separated, each zone is processed while the objects to be processed are sequentially moved to the next zone while maintaining an independent atmosphere, and the carbonization gas released from the carbonization zone into the furnace is burned by a burner. It is ignited and burns, and directly heats the dry distillation carbonization zone and the activation zone of the retort together with the combustion flame of the burner, and then heats the drying zone to heat the high-moisture workpiece, generating steam and odor.

At this time, the internal pressure of the drying zone increases,
In the activation zone, the burned carbonized gas is released into the furnace, and thus slightly lower than the atmospheric pressure.

For this reason, the water vapor and the odor generated in the drying zone flow into the activation zone through the pipe, and the material to be processed is activated and discharged from the retort.

The pipe is heated by the heat for heating the dry distillation carbonization zone, and the odor in the gas flowing therethrough is decomposed and deodorized by the heat, so that the calorific value for deodorization is not particularly required.

Therefore, there is an effect that carbonization can be performed efficiently.

The invention of claim 2 has the effect that the pipes connecting the drying zone and the activation zone are provided through the carbonized carbonization zone so that the retort does not increase in bulk. Since it is provided bypassing the zone, it is directly heated by the combustion gas and has a high deodorizing effect.

[0012] The invention of claim 4 is the invention of claim 1, 2, or 3.
According to the invention, since the drying zone is heated by driving the combustion gas into the drying zone, there is an effect that drying is promoted.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a carbonization furnace according to the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a furnace body made of a refractory, which is divided into right and left by a partition wall 6, and a right side thereof has a hearth 2 in which a suction hole 3 is formed.
Is divided into an upper primary combustion chamber 4 and a lower secondary combustion chamber 5.
A retort 8 made of a heat-resistant metal penetrating through both side walls and the partition wall 6 with a small gap is provided substantially horizontally, and a ring 9 fixed to the outer periphery of the retort 8 on both outer sides of the furnace body 1 is freely rotatable on a stand 10. It is supported by a supported roller 11 and is driven to rotate in one direction.

As shown in FIG. 2, the inside of the retort 8 is dried from the inlet side to the outlet side by a partition wall 12 communicating both sides of the partition plate 14 with a spiral tube 13 along the inner peripheral surface of the retort 8. A pipe 18, which is divided into a zone 15, a carbonization zone 16, and an activation zone 17, passes through the center of the partition plate 14 of the partition wall 12 on both sides of the carbonization zone 16 and communicates the drying zone 15 and the activation zone 17. Provided and carbonized carbonization zone 16 and activation zone 1
7 is provided with an exhaust pipe 19 for discharging gas in the retort 8 into the primary combustion chamber 4, and a screw connected to a hopper 22 through a closing plate 20 fixed to the furnace 1 in the drying zone 15. A conveyor 21, a stirring blade 23 and a hot air driving pipe 24 are inserted, and a guide blade 25 is spirally mounted on the outer periphery of the retort 8 in the drying zone 15.

Further, five burners 26 are provided in the primary combustion chamber 4 of the furnace body 1 and one burner 27 is provided in the secondary combustion chamber 5. A ventilation hole 7 for discharging gas to the atmosphere through the outer periphery of the drying zone 15 of the retort 8 by suction of the fan 28 is formed.

A part of the exhaust gas from the suction fan 28 is driven into the drying zone 15 of the retort 8 through the hot air driving pipe 24.

Next, the operation when carbonizing high moisture organic waste using the carbonization furnace of the present embodiment will be described.

When the burner 26 of the primary combustion chamber 4 and the burner 27 of the secondary combustion chamber 5 are burned and an object to be processed is charged into the hopper 22 while keeping the furnace interior at an appropriate temperature, the screw conveyor 21 drives the drying zone of the retort 8. 15 and is transferred while being dried and pulverized by the high-temperature gas passing through the outer periphery of the retort 8 and the hot air injected from the hot-air driving pipe 24 while being stirred by the stirring blades 23, and rotated between the retort 8 and the carbonized carbonization zone 16. The carbonization zone 16 through the spiral pipe 13 of the partition wall 12 provided
However, since the inside of the helical tube 13 is filled with the granular material to be treated, water vapor and odor cannot enter the dry distillation carbonization zone 16, and as described later, the pressure is slightly lower than the atmospheric pressure. It flows through the pipe 18 to the activation zone 17 and is heated as it passes through the high-temperature dry distillation carbonization zone 16, the steam becomes higher in temperature, and the odor is thermally decomposed and disappears.

Since the dry distillation carbonization zone 16 is partitioned by the partition walls 12 on both sides, the dried object to be treated is heated to a high temperature by the combustion flame of the burner 26 and a part of the organic matter is burned to reduce the reducing atmosphere. Most of the organic matter is decomposed into carbonization gas, and flows into the primary combustion chamber 4 through the exhaust pipe 19 and burns. Since the temperature inside the primary combustion chamber 4 rises, the burners 26 of the primary combustion chamber 4 are sequentially turned on. You can also erase them all and finally erase them all.

Exhaust gas flowing into the secondary combustion chamber 5 which has become negative pressure by the suction of the fan 28 through the suction hole 3 of the hearth 2 is reheated by the burner 27 and unburned carbon and odor are incinerated. However, when harmful substances such as dioxin are not decomposed, some of the burners 26 of the primary combustion chamber 4 may be burned to increase the temperature.

The exhaust gas thus detoxified is discharged from the fan 28 into the atmosphere while being swirled by the guide vanes 25 on the outer periphery of the drying zone 15 of the retort 8, during which the heat is exchanged to dry. Heat zone 15 sufficiently.

The granular workpiece carbonized in the dry distillation carbonization zone 16 passes through the spiral tube 13 of the partition wall 12 and is activated in the activation zone 1.
7 and heated by the primary combustion chamber 4 while being mixed with the high-temperature steam supplied from the drying zone 15 through the pipe 18, the tar remaining in the pores is removed, and the pores are made porous. The gas discharged from the spiral pipe 13 of the partition wall 12 and generated in the activation zone 17 is burned in the primary combustion chamber 4 through the exhaust pipe 19.

The porous carbide is effectively used as a soil conditioner or the like.

As another embodiment of the present invention, as shown in FIG. 3, a pipe 18 may be arranged outside the retort 8 to bypass the dry distillation carbonization zone 16.

EXAMPLE A sewage sludge having a water content of 80% was prepared by drying the sewage sludge having a length of 3
1, the carbonization zone 16 and the activation zone 17 each have a length of 1.5 m and a retort 8 having an inner diameter of 0.3 m. Then, carbide was obtained in 60 minutes from charging to discharging. First, all the burners were ignited, the temperature of the primary combustion chamber 4 of the furnace was raised to 750 ° C., and then charging was started. Although the internal temperature of the drying zone 15 was 520 ° C., the temperature gradually decreased due to the introduction of sludge, and the temperature gradually decreased from 480 ° C. to 470 ° C.
However, when the sludge passed through the drying zone 15 and entered the carbonization zone 16, the carbonization gas was ejected from the exhaust pipe 19 provided in the retort 8, ignited, and the temperature increased. Accordingly, the second and third burners 26 are sequentially turned off from the inlet side except for the first burner 26 (first from the inlet side of the retort 8), and finally the burner 27 of the secondary combustion chamber 5 is turned off.
The fire was extinguished except for the fifth burner 26 of the primary combustion chamber 4 (closest to the exit of the retort 8). At this time, the temperature of the secondary combustion chamber 5 also increased to 680 ° C., and the temperature of the drying zone 15 also increased to 520 ° C. to 530 ° C. At this time, the furnace was switched from manual to automatic control, and the dry distillation carbonization zone 16 was set to 750.
° C, the activation zone 17 is 850 ° C, and the secondary combustion chamber 5 is 850 ° C.
When the temperature was set to ℃, stable carbonization could be maintained. The secondary combustion chamber 5 is heated to 850 ° C. by the burner 26.
The unburned carbon is incinerated, and the high-temperature gas flows from the secondary combustion chamber 5 through the ventilation holes 7 to around the drying zone 15 and acts as drying energy. As a direct contact with the sludge to promote the evaporation of water. The remaining warm air was released into the atmosphere from the chimney. The exhaust gas was a harmless exhaust gas without odor and dust.

The raw sludge with a water content of 80% used in this experiment was 893 kg, the produced carbon was 55.8 kg, and the time required for the treatment was 510 minutes. LP gas consumption is 73.5kg
The amount of gas used per kg of raw sludge was 0.0823 kg.

The resulting carbide was a hard granular coal having a size of 5.00 mm or less and a bulk specific gravity of 0.53. The specific surface area of charcoal is 145
It was about 1/10 of activated carbon at m ² / g.

Comparative Example A retort penetrating through the inside of the furnace is a continuous carbonization furnace having a heating zone having an inner diameter of 0.3 m and a length of 3 m. There is no drying zone, and the dry distillation carbonization zone and the activation zone are spirals provided in the retort. A retort consisting of two chambers separated by a wall is installed in a furnace frame, and rotated while heating with a burner and a self-burning dry distillation gas to dry carbonize and activate. Naturally, the inlet and outlet are designed to block the intrusion of air, and the carbonized gas generated as in Example 1 is injected from the exhaust pipe that passes outside of the retort and self-burns. The activation zone is activated from the outlet side of the furnace. Water was injected through a thin pipe leading to the zone, and the water was turned into steam in the pipe for activation.

For drying, high-temperature gas of 650 ° C. discharged from the secondary combustion chamber of the carbonization furnace is guided to a hot air generator for drying by a duct, and further heated by a burner to increase the air volume and blow hot air of 700 ° C. into the drying furnace. For drying. The drying oven has an inner diameter of 0.5m,
Rotating blades and a lifter for crushing are installed in the pipe 2m in length. Sludge with a water content of 80% is broken down by the blades while hot air is blown in, lifted up by a lifter, and dried by contact with hot air while falling. It is a mechanism. The drying exhaust gas is an odorous gas mainly composed of water vapor, is sucked by a fan from a drying furnace, incinerated and deodorized through a deodorizing furnace heated to 850 ° C. by a burner, and released into the atmosphere. 90 kg of 80% moisture sludge was put into the drying furnace at an hour, and the moisture content after drying was 42.4%.
60 kg / h of dry sludge having a water content of 42.4% is continuously and automatically charged into the carbonization furnace, and the carbonization zone is 750 ° C. and the activation zone 8 is
After passing through 00 ° C. for 30 minutes, a carbide was obtained. At this time, the injection of water into the activation zone was 6 l / h. In this experiment, the primary combustion chamber burned the first and fifth burners out of the five burners, and the secondary combustion chamber maintained a temperature of 800 ° C. 544.2 kg of raw sludge having a water content of 80% was supplied to a drying furnace at 90.7 kg per hour to obtain 188.8 kg of dry sludge having a water content of 42.4%. 36.5 kg of this dried sludge per hour
34 kg of carbides could be produced by continuous feeding to the carbonization furnace. The resulting carbide had a bulk specific gravity of 0.58, a diameter of 5 mm or less, and was hard black granular carbide. The specific surface area of charcoal is 135
Although it is m ² / g, which is lower than activated carbon, it can be used sufficiently for growing plants. The LP gas used for this carbonization was 71.8 kg, of which 43% was in the dryer, 39.1% in the deodorization furnace, and 17.9% in the carbonization furnace. The fuel required for 1 kg of raw sludge was 0.132 kg.

The fuel (LP gas) required for carbonization of raw sludge having a water content of 80% was 0.0823 kg of LP gas per kg of raw sludge and 82.3 kg of LP gas for 1 ton treatment in the example, but was not used in the comparative example. 0.132 kg per 1 kg of sludge, 132 kg per ton
Consumed. This is apparently due to the fuel used for drying and deodorizing. In the case of the embodiment, the temperature of the secondary combustion chamber 5 is also maintained at 850 ° C., and the temperature of the activation zone 17 is also 8 ° C.
Although the temperature was set to 50 ° C. higher than that of the comparative example, the difference in fuel use was thus obtained, and it was demonstrated that the present invention greatly contributes to low fuel consumption by carbonization of high moisture sludge. By thus integrating the drying furnace with the carbonizing furnace and omitting the deodorizing furnace, the equipment becomes compact and the equipment cost is reduced, and the effect of the present invention is great.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a partition wall.

FIG. 3 is a sectional view of another embodiment of the retort of the present invention.

[Explanation of symbols]

 1: Furnace body 4: Primary combustion chamber 5: Secondary combustion chamber 8: Retort 12: Partition wall 13: Spiral tube 14: Partition plate 15: Drying zone 16: Carbonization zone 17: Activation zone 18: Pipe 19: Exhaust pipe 26, 27: Burner

Claims (4)

[Claims] 1. A drying zone from an inlet to an outlet by a partition wall that allows a flow of an object to be processed and blocks a flow of a gas in a metal retort that is rotated and driven substantially horizontally through a furnace body. An exhaust pipe for releasing gas in the retort into the furnace is provided in the dry distillation carbonization zone and the activation zone of the retort, corresponding to the dry distillation carbonization zone and the activation zone. A burner is provided at a position where the drying zone is heated from outside the retort by a combustion gas flowing from a position corresponding to the dry distillation carbonization zone and the activation zone of the furnace body. A continuous carbonization furnace provided with a pipe for supplying gas generated in the above to the activation zone. 2. The continuous carbonization furnace according to claim 1, wherein said pipe is provided through said dry distillation carbonization zone. 3. The continuous carbonization furnace according to claim 1, wherein the pipe is provided so as to bypass the dry distillation carbonization zone. 4. The continuous carbonization furnace according to claim 1, wherein the drying zone is heated by driving the combustion gas into the drying zone.