JP2006063179A - Carbonizing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for surely separating a carbonized product kept at a prescribed ignition temperature or above from an uncarbonized product igniting at a temperature below the prescribed ignition temperature. <P>SOLUTION: A screw type carbonizing furnace is obtained by nearly horizontally installing screw type carbonizing pipes kept in a low-oxygen atmosphere in the carbonizing furnace and heating and carbonizing a material which is transported with a screw type conveyor to be carbonized from the outside. The furnace is equipped with a separating mechanism for measuring the temperature of the carbonized material before cooling discharged from the carbonizing furnace and taking out the carbonized product with a product line when the measured value is the prescribed temperature or above and the uncarbonized material from a line separate from the line of the carbonized product when the measured value is below the prescribed temperature. Furthermore, there is provided a timer for calculating the time difference between the time when the temperature of the carbonized material before cooling discharged from the carbonizing furnace is measured and the time to change over the lines with the separating mechanism by the transport speed of the screw conveyor and delaying the changeover of the lines by time difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for carbonizing sewage sludge, livestock waste, and the like.

Details of the prior art are shown in FIG.
The screw-type carbonization furnace 2 includes a furnace body 5 whose outer shell is lined with a refractory, one-stage to several-stage screw-type carbonization pipes 1a to 1c penetrating the inside of the furnace, and dry distillation gas combustion for heating the carbonization pipe Composed of chamber 3. The heat required for carbonization is supplied by combustion of raw dry distillation gas discharged from the heating burner 6 and the nozzle 7 opened in the carbonization tube, and the exhaust is drawn out by the exhaust fan 15. The exhaust fan also serves to draw carbonized gas from the carbonization tube. A rotary valve 4a is provided at the supply port of the object to be carbonized and a rotary valve 4b is provided at the outlet of the carbide to block the carbonization pipe from the outside air.

  The object to be carbonized is heated without being directly in contact with the flame while being sequentially conveyed through the rotary valve 4a through the screw type carbonized pipes 1a to 1c provided with a screw conveyor driven by a motor 8, and evaporates and pyrolyzes moisture. The process is transferred. The high-temperature carbide after pyrolysis discharged from the carbonization furnace is cooled by a cooling device 9 made of, for example, a screw type cooling pipe, and taken out to the storage tank 14. The dry distillation gas is discharged from the nozzle 7 opened in the carbonization tube and burned in the dry distillation gas combustion chamber 3. The carbonized material is heated and carbonized by dry distillation gas combustion to a temperature of 400 to 1000 ° C. (generally speaking, this carbonization temperature is a heating temperature, not a carbonized product temperature). The high-temperature carbide after pyrolysis discharged from the carbonization furnace 2 is cooled by an optional cooling device and taken out. In the conventional example of FIG. 1, the cooling device 9 introduces cooling water from an inlet 11 into a jacket provided around the screw conveyor 10 and takes out the cooling water from the outlet 12, and directly supplies humidified water from the inlet 13 into the screw conveyor 10. A spraying combination system is used. In the prior art, when the humidified water is sprayed directly on the high-temperature carbide, the humidified and cooled carbide is discharged from the rotary valve 4 b to the storage tank 14.

Since carbides have self-heating characteristics, carbides produced at low temperatures ignite at lower temperatures as shown in FIG. FIG. 2 shows the relationship between the carbonization temperature of the carbonized sludge and the ignition temperature. The lower the carbonization temperature, the lower the ignition temperature. As a means for avoiding the risk of ignition of carbonized sludge in the carbonization step, there is a method of controlling the carbide temperature to a predetermined temperature while paying attention to the production temperature of the carbide (for example, JP-A-2001-192669, The temperature of the carbide discharged from the screw conveyor at the last stage or the preceding stage is measured, and the conveying speed of the screw conveyor is adjusted according to the measured value.) Because there are many control factors that affect the carbide temperature, temperature control Is not easy.
JP 2001-192669 A

If the temperature at which the carbides ignite is low, a combustion accident may occur at the storage location. In particular, carbonized sludge produced from sewage sludge has self-heating characteristics, and the temperature rises in places where the cooled carbides are stored as products such as fertilizers (for example, product tanks at production sites or purchased farmers). May ignite. For the purpose of avoiding such accidents, the Japan Sewerage Corporation is instructing to produce carbides with an ignition temperature of 280 ° C. or higher when carbonizing sewage sludge.
An object of the present invention is to provide a means for reliably separating carbonized products having a predetermined ignition temperature or higher from uncarburized substances that ignite at a temperature lower than that.

The present invention is a screw-type carbonization furnace in which a screw-type carbonization pipe maintained in a low oxygen atmosphere is installed substantially horizontally in a carbonization furnace, and a carbonized material conveyed by a screw conveyor is heated from the outside of the carbonization pipe and dry-distilled. The temperature of the carbide before cooling discharged from the carbonization furnace is measured, and when the measured value is equal to or higher than the predetermined temperature, it is a product line as a carbonized product. It is a carbonization apparatus characterized by providing a separation mechanism to be taken out in a line.
The separation mechanism calculates the time difference between the time when the temperature of the carbide before cooling discharged from the carbonization furnace is measured and the time when the line is switched by the separation mechanism based on the conveying speed of the screw conveyor. Has a timer to delay only.
More specifically, the separation mechanism includes a temperature sensor that measures the temperature of the carbide before cooling discharged from the carbonization furnace, a gate that divides the discharged carbide into a carbonized product line and an uncarbonized product line, and Control means for operating the gate so that the carbonized product is taken out in the product line as a carbonized product when the measured value measured by the previous sensor is equal to or higher than a predetermined temperature, and when the measured value is lower than the predetermined temperature, it is taken out in the separate line as uncarburized. Further, the time difference from the point where the temperature of the carbide before cooling discharged from the carbonization furnace is measured to the time when the carbide reaches the gate is calculated by the conveying speed of the screw conveyor, and the switching of the line is calculated from the measured time. A timer for delaying by the time difference may be provided.
The present invention further provides a recirculation line in which uncarburized substances (carbides whose carbonization temperature does not reach a predetermined temperature) taken out in a separate line from the carbonized product are recycled and carbonized again before the carbonization furnace.

The carbonization apparatus according to the present invention measures the temperature at the time of manufacture of the object to be carbonized, and only separates the carbide above the predetermined temperature as the carbonized product, so that it is possible to substantially avoid the uncarburized material from being mixed into the carbonized product. . Conventionally, the carbonization temperature is controlled by a method such as controlling the conveyance speed depending on the temperature in the vicinity of the screw carbonization tube in the final stage, but the present invention does not perform such difficult control, and the carbonization temperature is not controlled. By selectively fractionating carbides having a predetermined carbonization temperature or higher regardless of fluctuations, it has become possible to inexpensively and efficiently produce products having a carbonization temperature higher than the predetermined carbonization temperature.
In the present invention, when the temperature of the outlet of the carbonization furnace is measured and the line is switched by the separation mechanism, a carbonization temperature equal to or higher than a predetermined carbonization temperature is obtained by using a timer that can select a difference in arrival time depending on the conveying speed of the screw conveyor. The carbonized product which has can be provided reliably.
Furthermore, in the present invention, since another line for recirculating the uncarburized material taken out by the separation mechanism as a raw material to be carbonized is provided, the efficiency of the carbonization apparatus and the utilization efficiency of resources are increased.

Example 1
Embodiment 1 of the present invention will be described in detail with reference to FIG. The carbonization apparatus shown in FIG. 3 measures the temperature of the uncarburized material before cooling discharged from the carbonization furnace, and the product gate and uncarburized products are provided with a slide gate provided in the lower part of the screw-type cooling pipe depending on the temperature of the object to be carbonized. It shows the mechanism of sorting.
In FIG. 3, the carbonization apparatus has a screw-type carbonization furnace 2 and a cooling device 9 connected to the downstream side thereof. Of these devices, portions not related to the features of the present invention are partially omitted, but actually they have the same structure as the conventional example of FIG. 3, parts corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

A connection pipe 23 is connected between the outlet of the final stage screw-type carbonization pipe 1c of the carbonization furnace 2 and the cooling device 9, and a temperature sensor 16 for measuring the temperature of the carbide is installed inside the connection pipe 23. On the other hand, a product line 17 for taking out carbide products is provided at the bottom of the cooling device 9 on the downstream side, and a slide gate 18 is provided at the upper end thereof. The slide gate 18 is driven by a motor 22. The temperature of the carbide detected by the temperature sensor 16 is sent to the controller 20 via the signal line 19 where it is processed by an appropriate program having the following action to generate a control signal, which is transmitted via the control line 21. Then, by opening and closing the slide gate 18 by the motor 22, the carbides are separated according to the carbonization temperature. Thus, the part which controls the slide gate 18 from the temperature sensor 16 comprises the classification mechanism of this invention.
The controller 20 generates an activation signal that opens the gate to take out the product carbide when the temperature exceeds a reference temperature that distinguishes between product carbide and uncarbide, and closes the gate when the temperature is less than the reference temperature. The controller 20 calculates the time until the carbide at the temperature sensing point reaches the gate of the cooling device 9 from the speed of the screw conveyor 10 and delays the operation signal by that time to the motor 22 via the control line 21. Built-in timer to send.

  The reference temperature for judging product carbide and uncarburized is determined by obtaining the relationship between the carbide production temperature and ignition temperature as shown in FIG. For example, in the example of FIG. 2, assuming that the product carbide temperature is 450 ° C. or more and the ignition temperature is 280 ° C. or more, when making a carbonized product having an ignition temperature of 280 ° C. or more, the measured product temperature at the carbonization furnace outlet is 450 If the slide gate 18 at the lower part of the cooling device 9 is opened when the temperature is higher than 0 ° C., the carbide falls from this gate and becomes a product. When the measurement temperature falls below 450 ° C., the uncarburized material can be separated without falling as a product by closing the gate. On the contrary, when the carbide temperature becomes 450 ° C. or higher when the gate is closed, the gate is opened. The reference temperature can be set according to the desired carbonization temperature.

  Since the screw-type carbonization furnace quantitatively conveys the conveyed product from other types of carbonization furnaces, more accurate separation is possible by calculating the time difference and operating the separation mechanism. For example, similarly, when making a carbonized product having an ignition temperature of 280 ° C. or higher, when the measured product temperature falls below 450 ° C. and the gate is closed, the conveying speed of the screw conveyor, the temperature measurement position, and the branch location (gate ), When the gate is closed immediately before the uncarburized material of less than 450 ° C. arrives at the gate, the uncarburized material can be separated without falling as a product. When the carbide temperature becomes 450 ° C. or higher after the gate is closed, the gate is opened immediately after the arrival time of the carbide to be the product, contrary to when the carbide is closed.

  In FIG. 3, the temperature of the object to be carbonized after carbonization is measured at the outlet of the carbonization furnace, but the measurement location on the screw pipe may be an appropriate position on the final stage screw conveyor. Further, FIG. 3 shows an example in which a slide gate is provided in the lower part of the screw type machine cooling pipe, but a similar separation mechanism may be provided after the screw type cooling pipe.

Example 2
The carbonization apparatus of the second embodiment shown in FIG. 4 uses the same carbonization apparatus as that of the first embodiment (FIG. 1), but the uncarburized material separated by the separation mechanism is used as a part of the material to be carbonized and is supplied to the carbonization furnace. And is configured to re-carbonize.
That is, in this embodiment, the temperature of the uncarburized material before cooling discharged from the carbonization furnace 34 is measured, and it is installed after the cooling device 35 and is separated into product carbide and uncarburized according to the temperature of the object to be carbonized. FIG. 5 shows a flow in which uncarburized material that has not become a product is separated by an appropriate separation mechanism, and then the uncarbonized material is supplied to the conveyor 32 and carbonized again.
In FIG. 4, the non-carbonized material is returned to the transport conveyor 32, but may be returned to the dried sludge hopper 33 or the carbonization furnace 34.

The carbonization apparatus of FIG. 4 includes a dryer 31 for granulating and drying dehydrated sludge having a moisture content of about 80%, a carbonization furnace 34 for carbonizing the dried sludge, and a heat exchanger 38 for recovering heat from the combustion gas. And exhaust gas treatment cyclones 36 and 39.
A fixed amount of dehydrated sludge having a water content of about 80% is supplied to the dryer 31. The dryer 31 which is an internal heat type rotary kiln type blows the dry distillation gas of about 800 ° C. generated in the carbonization furnace 34 into the dryer drum, and rotates, agitates, granulates, and transfers the dehydrated sludge while containing a moisture content of 30. % To dry. The dried sludge is transferred to a dry sludge hopper 33 equipped with a quantitative supply device at the upper part of the carbonization furnace by the transport conveyor 32.

  The carbonization furnace 34 is an external heat kiln in which the inside of the furnace is passed through 3 to 6 screw conveyors, and the dried sludge supplied to the uppermost screw conveyor is sequentially transferred to the upper, middle and lower screw conveyors. . When the casing of the screw conveyor is heated to about 700 ° C. by the preheating furnace burner 42 at the lower part of the carbonization furnace, the dried sludge in the conveyor casing is pyrolyzed, that is, carbonized and carbonized in a low oxygen state.

If the temperature of the carbide is measured at the final stage of the carbonization furnace and is equal to or higher than a predetermined temperature (for example, 450 ° C.), this is cooled to about 40 ° C. by the cooling device 35 and then passed through the separator 45 to be a carbonized product. If it is 450 degrees C or less, it will judge that it is an uncarburized substance, and after cooling to about 40 degreeC similarly with the cooling conveyor 35, it isolate | separates with the sorter 45, and sends to the conveyance conveyor 32, and is re-carbonized.
The dry distillation gas generated in each stage of the screw conveyor is burned after being discharged from a dry distillation gas discharge hole provided in the upper part of the screw conveyor casing, and this is used as a heat source for dry distillation. Moreover, the combustion exhaust gas of the dry distillation gas is recombusted at 800 ° C. by the reburning furnace burner 43 for exhaust gas treatment, and also used as a heat source for the dryer.

  Exhaust gas from the dryer is sucked by a circulation fan 37 and separated by a cyclone 36, and then burned in a reburning furnace through a circulation gas heat exchanger 38 to decompose and remove bad odors.

  The exhaust gas thermally decomposed in the reburning furnace is sucked by the induction fan 40 and discharged from the smoke stack 41 to the atmosphere through the circulating gas heat exchanger 38 and the cyclone 39.

As described above, the carbonization apparatus according to the present invention measures the temperature at the time of manufacture of the object to be carbonized, and separates only the carbide above the predetermined temperature as the carbonized product, so that it is substantially avoided that uncarburized is mixed into the carbonized product. can do.
In the present invention, when the temperature of the outlet of the carbonization furnace is measured and the line is switched by the separation mechanism, a carbonization temperature equal to or higher than a predetermined carbonization temperature is obtained by using a timer that can select a difference in arrival time depending on the conveying speed of the screw conveyor. The carbonized product which has can be provided reliably.
Furthermore, in the present invention, since another line for recirculating the uncarburized material taken out by the separation mechanism as a raw material to be carbonized is provided, the efficiency of the carbonization apparatus and the utilization efficiency of resources are increased.

FIG. 1 is a detailed view of a conventional carbonization apparatus. FIG. 2 shows the relationship between the carbonization temperature of sludge and the ignition temperature. FIG. 3 shows a carbonization apparatus equipped with a sorting mechanism according to Embodiment 1 of the present invention. FIG. 4 shows a carbonization apparatus equipped with a sorting mechanism according to Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1c Screw type carbonization pipe 2 Carbonization furnace 3 Combustion chamber 4a Supply side rotary valve 4b Outlet side rotary valve 5 Furnace body 6 Heating burner 7 Nozzle 8 Motor 9, 35 Cooling device 10 Screw conveyor 11 Inlet 12 Outlet 13 Humidification water Inlet 14 Storage tank 16 Temperature sensor 17 Product line 18 Slide gate 19 Signal line 20 Controller 21 Control line 22 Motor 23 Connection pipe 31 Dryer 32 Transport conveyor 33 Drying sludge hopper 34 Carbonization furnace 36, 39 Cyclone 37 Circulating fan 38 Heat exchanger 40 Induction fan 41 Smoke stack 42 Preheating furnace burner 43 Reburning furnace burner 45 Sorting machine

Claims (5)

  A screw-type carbonization furnace in which a screw-type carbonization tube maintained in a low oxygen atmosphere is installed substantially horizontally in a carbonization furnace, and a carbonized material conveyed by a screw conveyor is heated from the outside of the carbonization pipe to dry distillation, The temperature of the carbide before cooling discharged from the factory is measured, and when the measured value is above a predetermined temperature, it is taken as a product line as a carbonized product. A carbonization apparatus provided with a mechanism.   The separation mechanism calculates the time difference between the time when the temperature of the carbide before cooling discharged from the carbonization furnace is measured and the time when the line is switched by the separation mechanism based on the conveying speed of the screw conveyor. The carbonization apparatus according to claim 1, further comprising a timer that delays only by a time.   The carbonization apparatus according to claim 1 or 2, wherein uncarbonized material taken out from a line separate from the carbonized product is supplied before the carbonization furnace and carbonized again.   The separation mechanism was measured by a temperature sensor that measures the temperature of the carbide before cooling discharged from the carbonization furnace, a gate that divides the discharged carbide into a carbonized product line and an uncarbonized product line, and a front sensor. 2. The carbonization apparatus according to claim 1, further comprising control means for operating the gate so that the carbonized product is taken out in the product line as a carbonized product when the measured value is equal to or higher than a predetermined temperature, and is taken out as uncarburized in the separate line when the measured value is lower than the predetermined temperature.   The control means further calculates the time difference until the carbide reaches the gate from the point where the temperature of the carbide before cooling discharged from the carbonization furnace is measured by the conveying speed of the screw conveyor, and the line switching is measured. The carbonization apparatus according to claim 4, further comprising a timer that delays the time difference by the time difference.

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