JPH0233754B2 - NETSUBUNKAIHOHO - Google Patents

Description

Detailed Description of the Invention The present invention comprises a fluidized bed pyrolysis tower and a fluidized bed incineration tower, and circulates a fluidized medium such as sand between the two towers to heat organic raw materials such as municipal waste and other solid waste. This invention relates to a two-column circulation thermal decomposition method.

The prototype of the two-column circulating pyrolysis device can be found in the technology used in the process industries for petroleum, coal, etc., but in order to apply this to solid waste such as municipal waste, the pyrolysis raw material must be solid. Technical problems such as non-uniform properties and the contamination of inorganic substances had to be solved from both hardware and software perspectives.

We will discuss the problems with the conventional two-column circulation type thermal cracker. The two-column circulation type pyrolysis equipment consists of a pyrolysis tower where the endothermic decomposition reaction takes place, and a pyrolysis tower where the endothermic decomposition reaction takes place.
It consists of a combustion tower where the combustion reaction of tar mainly takes place. In the combustion tower, the char, oil, tar, and, if necessary, the produced gas are combusted, so there is little variation in the amount of combustion exhaust gas, but in the pyrolysis tower, the composition, moisture content, particle size, etc. of the pyrolysis raw materials fluctuate. As a result, the amount of gas produced and the pressure at the top of the pyrolysis tower fluctuated, which sometimes hindered the stable circulation of sand.

In addition, the amount of gas produced when municipal waste is pyrolyzed,
An example of the composition of the generated gas is shown in FIGS. 1 and 2, respectively.

The composition of the gas produced and the amount of gas produced are greatly influenced and changed by the thermal decomposition temperature. On the other hand, if the composition, moisture content, etc. of the pyrolysis raw material change, the pyrolysis temperature cannot be kept constant, resulting in fluctuations in the gas composition and amount of gas produced. When the gas composition changes, problems arise in terms of the utilization of the generated gas, such as the need for modifications to burners and the like.

The present invention eliminates the above-mentioned drawbacks of the conventional method and achieves stable thermal decomposition by controlling at least one of stable control of the fluidized medium and stable control of the produced gas by stable control of the fluidized bed temperature. The object of the present invention is to provide a pyrolysis method that allows the pyrolysis to be carried out.

The present invention provides a fluidized bed pyrolysis tower, a fluidized bed incineration tower, a connecting pipe for guiding the fluidized medium in the fluidized bed pyrolysis tower to the fluidized bed pyrolysis tower, and a section for transporting the fluidized medium in the fluidized bed pyrolysis tower. A connecting pipe that leads the fluidized medium stored in the pumping section to the fluidized bed incineration tower, and a waste feeder that supplies solid waste to the fluidized bed pyrolysis tower. In a two-column circulation type thermal decomposition method for thermally decomposing organic raw materials, a supplementary fluidized medium is supplied to a fluidized bed incineration tower, the fluidized medium levels in the thermal decomposition tower and the incineration tower are detected, and the fluidization is started based on this signal. The filling amount of the fluidized medium is controlled by controlling either the media supply amount or the amount of foreign matter discharged from the pyrolysis tower or the incineration tower, and the pressure difference between the tops of the pyrolysis tower and the incineration tower or the fluidized medium between the two towers is controlled. Based on the level difference, it is possible to detect a deviation in the level of the fluidizing medium in both columns, and to correct this deviation, the pressure at the top of the column can be adjusted by controlling the opening of a valve installed in the pyrolysis gas outlet passage, or the pressure at the top of the column can be adjusted. It is controlled by adjusting the circulation amount, and the temperature of the pyrolysis tower and the temperature of the incineration tower are detected to control either the combustion amount of the auxiliary burner in the incineration tower, the circulation amount of the fluidized medium, or the amount of waste supplied. This thermal decomposition method is characterized in that the temperature of both columns is kept within a predetermined range.

The present invention will be explained with reference to the drawings based on examples.
The outline of the two-column circulation type pyrolysis apparatus will be explained with reference to FIG.

This device consists of a fluidized bed pyrolysis tower 1 where endothermic decomposition reactions take place, and a fluidized bed combustion tower 2 where combustion reactions of the coal, oil, and tar produced from this take place.
A fluid heat medium such as sand circulates between these. A part of the produced gas is recirculated and supplied as fluidizing gas to the pyrolysis tower 1 to form a fluidized bed at 700 to 800°C, and waste is removed by a conveyor 3.
The waste is sent from the silo 4 to the supply hopper 5, where it is fed into the fluidized bed 8 of the pyrolysis tower, where it is pyrolyzed and gasified while the waste feeder 6 adjusts the supply amount and seals the gas. The produced gas is cleaned and cooled and used as a high-calorie clean fuel.

The heating medium whose temperature has been lowered by the endothermic pyrolysis reaction is sent to the combustion tower pumping section 7 together with the char that is generated at the same time, where the chiar reacts with the air that lifts the heating medium and is combusted, and further combustion occurs. Complete combustion occurs in the tower fluidized bed 11 to raise the temperature of the heat medium.

A part of the chire, which is entrained in the produced gas and collected by the collection device 9, is supplied to the combustion tower fluidized bed 11 by the chir supply device 10, and is similarly combusted to raise the temperature of the heat transfer medium. In addition, oil and tar separated in the water treatment device 12 are also sent to the combustion tower fluidized bed 11 to be burned.

On the other hand, the combustion exhaust gas discharged from the combustion tower 2 is subjected to an aluminum removal machine 13 and a collection device 14 to remove dust such as ash. The dust-removed product gas and combustion exhaust gas discharged from both towers undergo sufficient heat exchange with circulating gas and air, respectively. The generated gas leaving the heat exchanger 15 is purified and cleaned by a gas cleaning device 16 and stored in a gas holder 17.

Heat exchanger 15 partially pressurized by blower 18
The gas is refluxed to the pyrolysis tower 1 as a fluidizing gas through the gas.

On the other hand, the combustion exhaust gas leaving the heat exchangers 19 and 20 is removed by a dust collector 21 and then released into the atmosphere from an exhaust chimney 22.

Nonflammable substances (foreign substances) in the pyrolysis raw materials are removed from the pyrolysis tower 1,
The sand discharged from the foreign matter discharging devices 23, 24, 25, which are comprised of valves, etc. located below the bottom of the combustion tower 2, is separated by a foreign matter sand separation device 26, and is sent to a sand hopper via conveyors 27, 28. Returned to 29. Foreign matter is stored in a foreign matter bunker 30 and transported to landfill.

Replenishment of fluid sand is carried out from bunker 31 to quantitative feeder 3.
2. The conveyor 28 quantitatively supplies sand to the hopper 29, and the sand is discharged to the discharge device 33 as appropriate according to the sand supply signal from the furnace body.
This is done by activating.

The waste water generated when the generated gas is cleaned in the gas cleaning device 16 is separated from oil and tar, and then further treated in the water treatment device 12 to be reduced to below the regulation value and then discharged.

The method and device for discharging foreign matter will be described with reference to the drawings. In FIG. 3A, water vapor for purging is used as the classification gas supplied to the foreign matter discharging pipe 103. The steam system includes a steam source 113 such as a boiler, valves 115, 116,
A steam inlet 111 for purging and a steam inlet 107 for classification are provided. 117 is a cooling device, 118 is a drain outlet, 102 is a floor plate, 10
8 is a fluidized bed.

During normal operation, a part of the produced gas is circulated by the blower 106 and enters the underfloor chamber 105 through the inlet 104 to act as fluidizing gas, and the steam system normally closes valve 115 and closes valve 116. When it is opened, water vapor as a classification gas is allowed to rise inside the foreign matter discharge pipe 103 through the inlet 107 to perform a classification action.

In this case, water vapor is not dangerous like produced gas, so it can be made to have a fairly high pressure, and a large pressure difference between it and the pressure inside the pyrolysis furnace 101 can be maintained. It is possible to reduce the rate of speed fluctuation, perform stable and accurate classification even when there are pressure fluctuations in the pyrolysis furnace 101, and reliably remove foreign substances. Water vapor pressure is 1-10Kg/cm ²
A certain degree is used. Since purge steam usually has a pressure of about 4 to 6 kg/cm ² , it is convenient to design the classification mechanism to handle this pressure. Further, in order to eliminate bridging in the furnace, it is preferable to have a pressure of 1 Kg/cm ² or more.

The water vapor that has entered the pyrolysis furnace 101 is discharged along with the generated gas together with water vapor from water contained in municipal waste, etc., and is condensed by, for example, a cooling device 117 and drained into the exhaust port 1 as a drain.
18 and can be easily separated. Furthermore, since water vapor is almost inert to thermal decomposition reactions and can be condensed and separated in the cooling device 117, there is no risk of deterioration in the quality of the thermal decomposition gas.

Although the above example uses a part of the produced gas as the fluidizing gas, a method using water vapor as the fluidizing gas is also conceivable. However, in this case, a large amount of latent heat is required to convert the condensed water into steam again, resulting in a decrease in thermal efficiency.

Even in conventional installations that use part of the produced gas as fluidizing gas, there are often steam sources for other purposes nearby, and in most cases steam piping for purging is already in place. , it is extremely easy to modify as in the above embodiment, and this is also one of the effects.

Note that the water vapor for purging is not necessarily in the underfloor chamber 105.
It is not necessary to blow into the foreign matter discharge pipe 103; In this case, equipment for switching between the inlet 111, the valve 115, and the valve 116 is not required. (3rd
In figure A, in the case of purge, valves 116, 109,
112 is closed and valve 115 is opened. ) FIG. 3B shows another embodiment, which includes a circulating product gas system having a valve 112, a blower 106, a valve 119, and an inlet 104, and a steam system having a steam source 113, a valve 120, a valve 116, and an inlet 107. are connected by a bypass having a valve 121.
122 is a differential pressure detector between two points at different heights in order to detect clogging in the foreign matter discharge pipe 103, and the signal from the detector enters the control mechanism 125 and is transmitted to the valves 121, 120.
control. 124 is a combustion tower, and 126 is a pumping section.

During normal operation, valve 120 is closed and valve 1
12, 119, 121, and 116 are opened, and a portion of the generated gas is supplied by the blower 106 to the blowing ports 104 and 107 as fluidizing gas and classification gas, respectively. If the pressure inside the pyrolysis furnace 101 fluctuates rapidly and the pressure of the classification gas is insufficient, resulting in a large amount of fluidized sand falling, or if there are many foreign objects stuck in the foreign object exhaust pipe 103, the differential pressure inside the foreign object exhaust pipe 103 will increase. is large, so it is detected by the differential pressure detector 122 and the valve 121 is
Close the valve 120 and open the high pressure steam inlet 10.
7 to blow up and remove the fluidized sand or foreign matter in the foreign matter discharge pipe 103, and when the condition returns to normal, the valve 12 is opened again.
0 is closed and valve 121 is opened. Valve 112 when stopped;
Close valves 119, 109, 121 and valves 116, 120
Open and purge with water vapor. When purging, open the valve 121 and open the air inlets 104 and 107.
Steam may also be supplied from valve 116
Alternatively, the air may be supplied only from the air inlet 104 with the air inlet 104 closed.

Next, to explain the combustion furnace, which is one of the most important parts of the two-column circulation pyrolysis apparatus, using drawings, in FIG. 221 is provided, and fluidizing gas is introduced from the blowing port 222. The outlet 223 at the upper end of the lift pipe 206 is provided above and protrudes from the gas distribution plate 220 which is the bottom of the combustion furnace 202 .

Since the combustion furnace 202 of the present embodiment is configured in this way, when the heat transfer medium lifted up from the storage tank 203 through the lift pipe 206 is spouted into the combustion furnace 202, there is already a portion inside the combustion furnace 202. The interference caused by the entered heat medium is significantly reduced, and pressure fluctuations within the pumping pipe and nozzle are also small, allowing stable pumping without the risk of blow-through. Furthermore, in the combustion furnace 202 of this embodiment, by providing a gas distribution plate 220 and a gas chamber 221 as a fluidization device, the heat medium in the combustion furnace 202 is brought into a fluidized state, and combustible gas such as LPG is heated in the fluidized bed. ,
It becomes possible to burn a heat source material such as fuel oil, and very efficient heat exchange can be performed through direct contact with the heat medium, and the flow of the heat medium into the communication pipe 204 becomes smooth. Stable operation improves controllability.

201 is a pyrolysis furnace, 203 is a storage tank, 204, 2
05 is a connecting pipe, 207 is a nozzle, 208 is a bottom,
209 is a burner, 210 is an exhaust port, 211 is a gas distribution plate, 212 is a gas chamber, 213 is a foreign matter exhaust pipe,
214, 215 are air inlets, 216 is a feeder, 2
17 is a discharge port, 218 is a valve, and 219 is a foreign matter discharge device.

Figures 3D and 3E show another embodiment, which uses a pipe grid 224 as the fluidizing device. The pipe grid 224 consists of pipes 226 having injection holes 225 for fluidizing gas. Since the pipe 226 is used under high temperatures, one end is fixed while the other end is left free in consideration of thermal expansion.
The ejection holes 225 are appropriately opened in the radial direction, axial direction, and other directions to have a diameter and number suitable for the required flow rate and flow rate. These spout holes 22
A fluidized bed can be formed by ejecting fluidizing gas from No. 5, and the effect is almost the same as that described above.

3F, 3G, and 3H illustrate various embodiments of pipe grid 224.

Regarding the stability of the flow of the fluidized medium in the two-column circulation type pyrolysis apparatus, during normal operation, the communication pipe connecting the two columns is gas-sealed by a sand moving bed. When the gases in both columns are mixed through the connecting pipe, the mixing of air into the pyrolysis column causes a decrease in the calorific value of the produced gas. From the viewpoint of producing high-calorie pyrolysis gas with a stable composition, it is desirable to ensure gas sealing. In order to ensure gas sealing between the two columns, it is sufficient that the communication pipe is sufficiently filled with sand, that is, the bed levels of both columns are controlled within a certain range.

The bed level in the two-tower circulation system is H _R12 =〓ΔPγ±{(δ _R1 −δ _R2 ) + f(F _S , V
_f )}+γ _R21・W/γ _S・A _R21 /γ _R12 (1+γ _R21 /γ _R
12・A _R12 /A _R21 ) H _R : Layer level ΔP〓: Differential pressure between tower tops δ _R : Experimental constant F _S : Sand circulation amount V _f : Pyrolysis tower superficial velocity γ _R : Experimental constant W _S : Sand Filling amount γ _S : Apparent specific gravity of sand A _R : Fluidized bed cross-sectional area 1; Pyrolysis tower 2; Combustion tower.

That is, bed level is a function of sand loading, sand circulation, pyrolysis tower superficial velocity, and overhead differential pressure.
A feature of this circulation system is that the amount of sand circulating has a linear relationship with the amount of air pumped into the combustion tower, and is not affected by the amount of gas circulating in the pyrolysis tower. Therefore, if the sand circulation amount is given by the energy balance from the raw material supply amount, moisture content, and temperature conditions of both columns,
The amount of air to be pumped is uniquely determined, and the amount of circulating gas, that is, the superficial velocity of the pyrolysis column, is selected at a value that maintains a good fluidization state, independently of the amount of air to be pumped. Once the sand circulation amount and the superficial velocity of the pyrolysis tower are set as described above, long-term stable operation is easily possible by adjusting the differential pressure between the tops of the tower while monitoring both tower layer levels. In other words, if the upper and lower limits of the level of both towers are set from the structural specifications such as the position of the connecting pipe, from the above formula,
The operating range of the tower top differential pressure ΔP〓 and the sand filling amount WS is 4th.
It becomes the diamond shape shown in the figure. The operating conditions for ΔP and Ws should be around the center of the figure, and it is desirable for the operating range to be located on the WS axis as shown in the figure.

Conventionally, in order to maintain stable operation, four factors were considered: sand filling amount, sand circulation amount, pyrolysis tower superficial velocity, and tower top differential pressure.
However, in the control method according to the present invention, multiple types of physical quantities in the circulation system of the fluid medium, such as sand filling amount, sand circulation amount, A device that detects the superficial velocity of the pyrolysis tower and the differential pressure between the tops of the tower, and controls each physical quantity comprehensively and optimally to operate within the stable range in order to satisfy the stable operation range determined by using these multiple types of physical quantities as parameters. It is.

The individual control methods will be described below.

First, regarding sand filling amount control, the level of each fluidized bed is measured from the pressure difference between the upper and lower fluidized beds of both towers, and the amount of sand packed into both towers is grasped. Therefore, control can be achieved by operating the sand supply device and the foreign matter discharge device using the control device to supply and discharge the sand respectively.

To explain the embodiment using drawings, as shown in FIG. 5, the sand supply device includes a hopper 29, a supply pipe 3
4, 35, 36, a rotary feeder 37 and a valve 38 are provided as a cutoff mechanism and a supply mechanism, and a sand level detector 39 is installed in the hopper 29 to detect the lowest level and highest level of the sand level setting. , 40 are provided. 41 receives signals from differential pressure detectors 42, 43 or sand level detectors 39, 40, and operates a rotary feeder 37, a valve 38, or a quantitative feeder 3, which will be described later.
2. A control mechanism that controls the operation of the conveyor 28. In order to replenish sand to Hoppa 29, Bunka 3
1. A quantitative feeder 32 and a conveyor 28 are provided. The quantitative feeder 32 discharges sand from the bunker 31 at a predetermined flow rate, and may be an electromagnetic feeder, a vibration feeder, a rotary feeder, a table feeder, etc., and the flow rate may be controlled. The conveyor 28 is for transporting sand to a high place, and includes bucket elevators, screw conveyors, etc.
Flight conveyors, pneumatic transportation devices, etc. are used.

42 and 43 are upper and lower pressure differential detectors in the fluidized bed that detect excess or deficiency of sand in the pyrolysis device and send the signal to a control mechanism to control the operation of the supply device.

During normal operation, the hopper 29 stores an amount of sand necessary for replenishment. That is, the position of the sand surface detector 40 is set to the position of the sand surface corresponding to the required amount. If the sand level has not reached the position of the sand level detector 40, the control mechanism 41 is activated by the signal from the sand level detector 40, and the conveyor 28 and quantitative feeder 32 are activated to discharge the sand in the bunker 31. It is lifted and sent into the hopper 29. When the sand surface reaches the sand surface detector 40, the quantitative feeder 3 is
2. Stop the operation of the conveyor 28.

Further, the operation of the quantitative feeder 32 and the conveyor 28 may be stopped after reaching the sand level detector 40'.

When there is a shortage of fluidized sand in the pyrolysis device, it is detected by the differential pressure detectors 42 and 43, and the control mechanism 41 is actuated by the signal to start the rotary feeder 37 and transfer the sand in the hopper 29 to the supply pipes 34 and 35. ,36
It is supplied into the combustion tower 2 through. Valve 38 normally remains open. When the sand level in the hopper 29 lowers and reaches the position of the sand level detector 39, the control mechanism 41 stops the operation of the rotary feeder 37. The valve 38 is normally open, but since the rotary feeder 37 rotates while holding sand between its rotary blades, it acts as a blocking mechanism that prevents sand from falling freely and blocks part of the supply path. While working, it also acts as a supply mechanism.
When the rotary feeder 37 stops or when the supply flow rate is small, the rotary feeder 3
Since the supply pipes 35 and 36 below 7 are not filled with sand, the pressure inside the combustion tower 2 reaches the bottom surface of the rotary feeder 37, and this pressure pushes the gas inside the combustion tower 2 upward through the gap between the sand. A force is applied to prevent the sand from leaking to the rotary feeder 37 and to blow the sand above the rotary feeder 37 upward.

On the other hand, the position of the sand surface detector 39 is such that its height H from the rotary feeder 37 has a head of sand that can sufficiently resist the pressure, and is long enough to stop the leakage of the gas. has been selected.

Since the rotary feeder 37 is stopped by the sand level detector 39 and the control mechanism 41 and the height of the sand level is maintained so as not to be lower than H, the gas in the combustion tower 2 does not leak or blow through. Instead, the sand on the rotary feeder 37 satisfies the function of a material seal. If the height of the sand surface is H or higher, the material seal function will be maintained even when the rotary feeder 37 is in operation, and therefore, even if the pyrolysis equipment is in operation and under high pressure, the fluidized sand will remain in place. Replenishment can be carried out.

If the sand surface reaches the sand surface detector 39 and the rotary feeder 37 is stopped, but there is still insufficient fluidized sand in the pyrolysis device, the control mechanism 41 described above is activated.
The conveyor 28 and quantitative feeder 32 are driven by the action of , and after confirming that the necessary amount of sand has been replenished into the hopper 29 from the bunker 31, the rotary feeder 37 supplies it again. If the capacity of the conveyor 28 and quantitative feeder 32 is selected to be larger than the capacity of the rotary feeder 37, the conveyor 28 and quantitative feeder 32 can be operated continuously or intermittently, and the rotary feeder 3 can be
7 can be operated continuously, and there is no need to interrupt for replenishment.

If the sand level height becomes lower than H during operation due to failure or other reasons, there is a risk of leakage or blow-through, so the sand level detector 39 detects the drop and the control mechanism 41 closes the valve 38 to prevent danger. do. Further, when sand is removed from the supply path for maintenance of the rotary feeder 37, the operation of the pyrolysis apparatus can be continued by closing the valve 38.

In another embodiment, the rotary feeder 37 is operated after opening the valve 38 by the operation signal of the rotary feeder 37, and the rotary feeder 37 is stopped by the stop signal and the valve 38 is then closed. It may also be an interlocking mechanism.

The shutoff mechanism is not limited to the rotary feeder 37, but may be any mechanism that can discharge a predetermined flow rate while maintaining a layer of sand with a height of H or more above the shutoff mechanism itself, such as a screw feeder, a valve, or the like. It is also possible to provide only the valve 38 and supply sand at a predetermined flow rate while maintaining the sand above the height H by the orifice effect of the valve 38 with an appropriate opening degree.

Various types of sand surface detectors 39 and 40 are used, such as a rotating blade type and a capacitance type.

The sand is discharged by a foreign matter discharge device 24 provided below the combustion medium fluidized bed 8 in response to a discharge signal. The fluid is discharged from the bottom of the fluidized bed through piping until the discharge signal is released by opening and closing the valve. Further, the foreign matter may be discharged from the combustion tower pumping section 7 by the foreign matter discharging device 25.

In this example, since the sand is directly supplied to the fluidized bed combustion tower 2, the level of the fluidized bed in the combustion tower 2 can be adjusted quickly, ensuring the absolute amount of fluidized medium and Adjustments to offsets in the fluid medium level can be made quickly. This offset adjustment can also be performed by opening the valve 62 in accordance with the tower top pressure to adjust the tower top pressure, as will be described later.

Next, we will discuss sand circulation amount control.

Sand circulation amount control is performed as follows. That is, once the sand circulation amount is determined, the amount of pumping air and the amount of ring air injected from the vicinity of the pumping air outlet are determined, and the ring air amount is finely adjusted so that the set sand circulation amount becomes constant.

An example of sand circulation amount control will be explained using drawings.

The vicinity of the nozzle 44 and control related equipment will be explained with reference to FIGS. 6 to 8. The flange-shaped inlet 46 at the lower end inlet of the lift pipe 45 and the spout 4 of the nozzle 44
7, the distance Δh from the entrance 46 is made small.
The jet nozzle 47 is closer to the surface 48 corresponding to the free surface of the granular material defined by the angle of repose line drawn from the outer edge of the
In the protruding and stationary state, the spout 47 is arranged so as not to be buried in the powder. Furthermore, a fluidizing ring 49 is attached to the lower part of the nozzle 44, and the ring air is transferred to the flowmeter 5.
0, air is supplied through the flow rate adjustment valve 51. The fluidizing ring 49 has a ring-shaped jet nozzle 52 for ring air arranged diagonally downward, vertically downward, or horizontally, as shown in FIG. 8 as an example. The ring air blown out from the fluidization ring 49 flows through the nozzle 4
4. Disturbs the heat medium around 4 and reduces the angle of repose. This flow facilitates the flow of the heat medium to the upper part of the nozzle 44, and the ejecting action of the nozzle portion by the pumping gas causes the heat medium to be sucked into the flap-shaped inlet 46.

At this time, the degree of activity of the flow near the nozzle 44 changes depending on the amount of air supplied to the fluidization ring 49, and the amount of the heat medium flowing into the upper part of the nozzle 44 also changes. Figure 9 shows the experimental results of the relationship between the fluidization ring supply air amount and the heat medium pumping amount (circulation amount), where A is the upper limit curve, B is the stable pumping region C ₁ , C ₂ ,
At C ₃ , the amount of pumped air is C ₁ > C ₂ > C ₃ . This figure shows that when the amount of air supply exceeds a certain value, the amount of circulating heat medium increases in proportion to the amount of air supply.
Therefore, according to this method, not only the amount of pumping can be stabilized, but also the amount of pumping can be controlled.

On the other hand, the pressure loss within the transport pipe in a powder transport device varies depending on the mixing ratio of the transport gas and the substance to be transported. For example, in FIG. 6, the inside of the lift pipe 45 is a thin transport layer, and therefore the lift pipe 45
The amount of circulation can be measured by detecting the differential pressure between two measuring points with a differential pressure detector. However, in the lift pipe, since the gas and the heat medium form a gas-solid-liquid phase flow, the pressure measurement hole is often clogged with the heat medium, which is not the best method. Therefore, a measurement hole 53 near the pumping air supply nozzle 44 which has the same effect, and a measurement hole 54 near the free board at the top of the furnace where the heating medium does not scatter.
The circulation amount can be measured by detecting the differential pressure ΔP with the differential pressure detector 55. In this case, there is less clogging of the pressure detection hole with the heat medium, so more stable pressure detection is possible.

Reference numeral 56 denotes a control mechanism which controls the valve 51 in response to a signal from the differential pressure detector 55. As mentioned above, the amount of air in the fluidizing ring is adjusted by controlling the valve 51, and the amount of heat medium to be pumped, that is, circulated. The amount can be controlled.

Here, as shown in FIG. 9, there is an upper limit to the amount of sand circulation relative to the amount of pumped air, and if the amount of sand circulation is increased beyond that, air will blow through to the pyrolysis tower through the lower communication pipe.

Therefore, when the amount of pumped air is determined, an upper limit value is set for the amount of sand circulation to prevent the phenomenon of blow-through of the connecting pipe, so if a larger amount of sand circulation is required, valve 51' is set. Just increase the flow rate.

Next, we will discuss the superficial velocity control of the pyrolysis tower.

The superficial velocity of the pyrolysis column is determined to maintain a good fluidization state, and this is done by controlling the flow control valve or the rotational speed of the blower.

To explain the embodiment with reference to the drawings, in FIG. 10, a part of the generated gas is pressurized by a blower 66 and used as fluidizing gas for the pyrolysis tower.

The flow rate is measured by the flow body 67, and based on the difference from the set value, the control mechanism 68 controls the rotation speed of the flow rate regulating valve 69 or the blower 66 to keep the flow rate constant. Alternatively, the temperature of the fluidized bed of the pyrolysis tower may be measured by the temperature detector 70 and the flow rate may be converted into temperature to perform the above control so that the superficial velocity of the pyrolysis tower becomes constant.

Next, we will discuss the differential pressure control between the tower tops.

The differential pressure between the tower tops is controlled by pressure regulating valves provided downstream of each tower so that the tower top pressures of both towers reach a set value.

To explain the embodiment using the drawings, in FIG. 10, 57 detects the pressure difference ΔP ₀ between the pressure at the top 58 of the pyrolysis tower 1 and the pressure at the top 59 of the combustion tower 2 and outputs a signal. The emitting pressure difference detector, 60 is the decomposition column 1
A pressure detector 61 detects the pressure at the top 58 of the tower and issues a signal. Reference numeral 61 is a control mechanism that controls a valve 62 in response to a signal from the pressure detector 60. When the tower top pressure becomes high, the valve 62 is opened. A control mechanism 63 controls the valve 64 in response to a signal from the pressure difference detector 57, and operates to open the valve 64 when the top pressure of the column increases. In this case, of the signal lines A, B, C, and D, A and D are used. In another embodiment, the control mechanism 6
Instead of controlling the valve 64 with the control mechanism 63, the pressure detector 65 at the top 59 of the combustion tower 2 may be detected and the control mechanism 63 may operate the valve 64 in accordance with the signal. This is an example in which A and B of signal lines A, B, C, and D are used.

Alternatively, the pressure detector 65 may control the valve 64 via the control mechanism 63, and the pressure difference detector 57 may control the valve 62 via the control mechanism 61. This is an example in which B and C of the signal lines A, B, C, and D are used. In this case, the pressure at the top 59 of the combustion tower 2 is relatively stable, so good control can be achieved.

In this way, the sand filling amount, sand circulation amount, superficial velocity of the pyrolysis tower, and differential pressure between the tops of the tower, which were selected as multiple types of physical quantities, each have their own control mechanisms, but experiments are performed from each operating point.・Understand where the vehicle is being operated in the stable operation region determined through research,
By providing a control mechanism that judges at which point the vehicle should be operated and feeds back the command to each control mechanism, safe and stable operation can be performed, and moreover, one-man control is possible.

In other words, as shown in Figure 11, the amount of sand filled is:
The amount of sand circulation is determined from the pressure difference between the top and bottom of the combustion tower, and the superficial velocity of the pyrolysis tower is determined from the measurement of the circulating gas flow rate. Desired. An optimal driving area is set at the center of the safe driving area, and a judgment is made as to whether or not the vehicle is being driven within this area.

Based on the judgment, a status quo maintenance signal or an operation modification signal is issued, and a command is given to each of the aforementioned control devices to operate each control mechanism to maintain stable operation.

As the plurality of types of physical quantities, three types of control other than the superficial velocity of the pyrolysis tower may be taken up among the above four types.

The selection of the optimal stable operation region is performed based on the following considerations.

The two-column circulation type pyrolysis device is composed of a pyrolysis tower 1 (reducing atmosphere) where the raw material is thermally decomposed, and a combustion tower 2 (oxidizing atmosphere) where the char produced by the thermal decomposition is combusted. Both towers are connected by an upper connecting pipe and a lower connecting pipe.

During normal operation, the introduction of air into the pyrolysis tower 1 due to the blow-by phenomenon or the generation of bubbles in the connecting pipe not only causes a decrease in the calorific value of the pyrolysis product gas, but also causes the blow-by phenomenon to occur over a long period of time. Stable operation cannot be expected. In this way, in order to ensure long-term stable operation and at the same time obtain high-calorie pyrolysis gas with a stable composition, it is necessary to ensure gas sealing in the connecting pipe.

In the apparatus shown in this embodiment, the gas seal in both communication pipes is performed using a material seal made of a heat medium (hereinafter referred to as sand). Therefore, in order to ensure gas sealing between both towers, it is necessary to sufficiently fill the communication pipe with sand.
That is, it is sufficient that the layer levels of both towers are controlled within a certain range.

By operating the pilot plant of this system, the above items were confirmed and the pyrolysis tower layer level H _RA
and the operational range of _HRG at the combustion tower layer level. This operating region is as shown below.

H _RA lower limit (H _RA .mm): The sand layer level required to sufficiently fill the connecting pipe with sand, that is, the sand layer level up to the lower connecting pipe entrance.

Upper limit ( _HRA.max ): Maximum sand layer level obtained from the blower discharge pressure for fluidization. This is determined by the blower.

H _RG lower limit (HR _RG .mm): The sand layer level required to sufficiently fill the connecting pipe with sand. In other words, the sand layer level up to the entrance of the upper connecting pipe.

Upper limit (HR _RG . max): The smaller of the maximum sand layer level at which auxiliary combustion can be performed well with an auxiliary combustion burner, or the maximum sand layer level obtained by the discharge pressure of the blower for fluidization.

In addition, through theoretical analysis and experiments based on the pressure balance of this system, we found that the levels of both tower layers are expressed by the following equation.

H _RA = f ₁ (W _S , F _S , V _f , ΔP _T ) H _RG = f ₂ (W _S , F _S , V _f , ΔP _T ) where W _S : Sand filling amount F _S : Between both columns Sand circulation amount V _f : Surface velocity ΔP in the pyrolysis tower fluidized bed _T : Differential pressure between the tops of both columns In other words, the sand filling amount, sand circulation amount,
It is a function of the superficial velocity of the pyrolysis column and the differential pressure between the tops of the column.

In this system, H _RA and H _RG are determined.
The values of W _S , F _S , V _f , and ΔP _T are operated in the following ranges.

In other words, W _S is originally determined by the size and structure of the furnace, but it is the amount of sand that provides the sand layer level that should be 300 mm < H _RA and H _RG < 300 mm during normal operation.

F _S is a value determined by the energy balance from the raw material supply amount, moisture content, and temperature conditions of both columns (usually a value such that the temperature difference between the fluidized beds of both columns is 20 to 300℃) It is. Especially in this system
F _S has a linear relationship with the amount of air pumped to the combustion tower, and can be set independently without being affected by the amount of circulating gas in the pyrolysis tower.

V _f is independent of the amount of pumped air; the lower limit is the minimum value at which good fluidization can be obtained, and the upper limit is the value at which significant wear and scattering of the heating medium does not occur.
Therefore, V _f operates in the region of 0.4 m/s<V _f <3.0 m/s.

Normally, when the amount of produced gas is not generated
Set and operate so that V _f =0.4 to 1.2 m/s. However, due to the generation of generated gas, V _f
increases by that amount.

Normally, when generated gas is generated, the operating point is selected so that V _f =0.8 to 2.5 m/s.

As for ΔP _T , V _f increases due to the generation of generated gas, which changes the layer levels H _RA and H _RG of both towers, but this
Set ΔP _T so that it is within the upper and lower limits of H _RA and H _RG and operate. In normal operation, -5000mmAg<ΔP _T <5000mmAg.

Expressing the above, H _RA , min < H _RA = f ₁ (W, F _S , V _f , ΔP _T ) <
H _RA , max H _RG , min < H _RG = f ₂ (W, F _S , V _f , ΔP _T ) < H _RG ,
max, H _RA , min, H _RG , max, H _RG , min,
When the operating region is obtained by substituting the values of H _RG , max, W _S during operation, and F _S determined from the throughput, it becomes the region within the diagonal lined diamond shown in FIG. 11A.

During operation, long-term stable operation is possible by controlling ΔP _T or V _f so that it falls within this diamond-shaped region.

In addition, by setting F _S that matches the throughput and further setting V _f at the time of generated gas generation, an operating region as shown in Figure 11B can be obtained, and ΔP _T and W are included within this region. Of course, long-term stable operation is also possible by controlling _S.

In the embodiments described above, the fluidizing medium filling amount
W _S , fluidized medium circulation amount F _S , pyrolysis tower superficial velocity V _f ,
Using the value of the differential pressure ΔPr between the tops of both columns, the W _S , F _S ,
The values of V _f , ΔPr and the bed level of the fluidized bed in both columns H _RA ,
From the relationship with H _RG , controlling at least a part of the W _S , F _S , V _f , and ΔPr so that the layer levels H _RA and H _RG fall within an allowable range to prevent blow-through between the two towers; Control is performed to stabilize the flow of the fluid medium.

Furthermore, when the processing capacity increases, the F _S is changed so that the temperature difference between the fluidized beds in both columns is always 20 to 300℃.
Long-term stable operation is possible by operating within the same range as described above.

This system has the extremely advantageous property that if the operating point is set at the center of the stable region using the control described above, even if the operating point fluctuates due to any disturbance, it will converge to the center again. It's very easy.

Next, we will discuss the control mechanism that stabilizes the product. Conventionally, the operating point for each of the raw material supply amount, sand circulation amount, and auxiliary burner generated gas amount was determined independently by the operator. The energy balance was disrupted due to fluctuations in the composition and moisture content of the pyrolysis raw material, which led to fluctuations in the pyrolysis temperature and, as a result, the gas composition and gas production amount became unstable.

In order to stabilize the product, the pyrolysis temperature in the pyrolysis tower is controlled to be constant as a physical quantity in the circulation system of the fluidized medium. As shown in Figures 1 and 2, the amount of gas produced and the gas composition change depending on the pyrolysis temperature, so even if the composition of the raw material changes, if the pyrolysis temperature is controlled to be constant, the product Stability is measured.

Once the composition, moisture content, and supply amount of the pyrolysis raw material are determined, the amount of heat to be supplied to the pyrolysis tower is determined, and the amount of sand circulation, the fluidized bed temperature in both towers, and the combustion amount of the auxiliary burner are determined. That is, the amount of heat Q _A supplied to the pyrolysis tower by the sand, which is a heat medium, is expressed by the following equation.

Q _A = F _S . C. (TR _RG − T _RA ) …(1) However, F _S : Sand circulation amount C : Specific heat of sand T _RG : Combustion tower fluidized bed temperature T _RA ; Pyrolysis tower fluidized bed temperature On the other hand, in the pyrolysis tower The heat Q _B removed from the sand is Q _B = {Q ₁ (1-W) + Q ₂ W + Q ₃ (1-W) + Q ₄ φ}
W+Q ₅ +Q ₆ ...(2) However, Q ₁ ; Required amount of thermal decomposition per unit weight of raw material Q ₂ ; Amount of heat given to water per unit weight of raw material W; Raw material moisture content Q ₃ ; Produced gas, produced oil, Amount of heat per dry weight of raw material given to the char Q ₄ ; Amount of heat per unit weight given to the non-combustibles φ; Non-flammable fraction Q ₅ ; Amount of heat given to the fluidizing gas (amount of fluidizing gas = constant) Q ₆ ; Wall surface of the pyrolysis tower Heat loss from (approximately constant) W: Raw material supply amount When the heat balance is balanced, assuming Q _A = Q _B , the pyrolysis tower fluidized bed temperature T _RA is derived as follows.

T _RA = T _RG - {Q ₁ (1-w) + Q ₂ w + Q ₃ (1-w) + Q ₄
φ}W+Q ₅ +Q ₆ /F _S C…(3) Here, Q ₀ =Q ₁ (1-w)+Q ₂ w+Q ₃ (1-w)+Q ₄ φ
…(4) Then, T _RA = T _RG −Q ₀ W + Q ₅ + Q ₆ /F _S C …(5) For fluctuations in raw materials (variations in Q ₁ , Q ₂ , w, φ, W), Thermal decomposition temperature (pyrolysis tower fluidized bed temperature) T _RA
In order to keep constant, the following methods can be considered.

(a) Control of the raw material supply amount W (b) Control of the sand circulation amount F _S (c) Control of the burner combustion amount (related to _TRG ) First, a method for controlling the raw material supply amount W will be explained. Changes in properties such as composition and moisture content of pyrolysis raw materials (5)
In the equation, Q ₀ varies.

If the sand circulation amount F _S and the combustion tower fluidized bed temperature T _RG are kept constant, in order to keep the pyrolysis tower fluidized bed temperature T _RA constant, as can be understood from equation (5), It is sufficient if Q ₀ W + Q ₅ + Q ₆ is constant. However, the pyrolysis tower fluidized bed temperature
If T _RA is constant, Q ₅ and Q ₆ are almost constant, so it is sufficient if Q ₀ W≒constant. That is, the raw material supply amount W may be controlled so as to offset the fluctuation of Q ₀ .

An embodiment of the raw material supply device will be described with reference to FIG.

The most important parts of the raw material supply device are formed by a hopper 5, a taper screw feeder 71, a crusher 72, and a straight screw feeder 73. Amount control can be performed.

As a supply device for supplying municipal waste to the pyrolysis tower 1, a straight screw feeder 73 as a rear stage supply section, an intermediate chamber 74, and a tapered screw feeder 71 as a front stage supply section are provided. The tapered portion 75 of the IDA 71 compresses the waste to act as a material seal, and a crusher 72 is provided in the intermediate chamber 74 to crush the solidified waste.

An overflow type quantitative hopper 5 is provided at the inlet of the tapered screw feeder 71 to supply a constant quantity. In other words, it is equipped with a collection mechanism that allows the pyrolysis raw materials brought in in excess of the hopper capacity to overflow under its own weight and returns them to the previous stage equipment, and the raw material waste is first transferred to a silo 4 equipped with a storage tank and quantitative discharge device. The raw material enters the hopper 5 by the conveyor 3, and is further fed into the intermediate chamber by a pre-stage supply section having a tapered screw feeder 71. At this time, the input amount Qc is in the relationship Qc>Qs compared to the supply amount Qs, so the garbage accumulates on the hopper 5 and maintains the garbage level height h while Qc
The amount corresponding to -Qs overflows and returns via the chute 76 and is returned by the conveyor 77 to the silo 4 equipped with a storage tank and quantitative discharge device. A lid 79 is connected to a cylinder 80 by a hinge 78 on the upper edge of the hopper 5.
It is installed so that it can be opened and closed freely. Normally, this lid 79 is fully opened, but when the temperature of the pyrolysis tower 1 is being increased, the supply of waste disappears and the waste inside the taper screw feeder 71 is often not in a sufficient state to perform material sealing. Therefore, during temperature rising operation, the lid 79 is closed and sealed.

Alternatively, as shown in FIG. 12A, the cylinder 80,
Two sets of lids 79, 79' opened and closed by 80' may be used to provide two-stage sealing. In the case of the example shown in FIG. 12, dust accumulates on the sealing surface, making it impossible to achieve a complete seal, but in the case of the example shown in FIG. 12A, the sealing surface is vertically downward, so there is an advantage that no dust accumulates.

81 is a chute that supplies waste to the silo 4 with a storage tank and quantitative discharge device; 82 is a level detector;
3 is a fluidized bed.

To explain the operation of the feeding device after the taper screw feeder 71, since the straight screw feeder 73 opens into the fluidized bed 83, the opening is hot, so if the feeding speed is slow, the waste will melt and stick. Therefore, it is necessary to feed the material at a speed that is at a limit that does not cause melting and sticking, that is, at a speed that is higher than the melting speed. In the case of municipal waste, experiments and research have shown that it is practically desirable to supply the waste at a rate of 15 cm/sec or more.

The taper screw feeder is preferably 15 cm/sec or less, but it is possible to use 15 cm/sec or more.

In the raw material supply device configured in this way,
By providing a variable mechanism for the screw rotation speed of the tapered screw feeder 71 and having the rotation speed controlled by the control device 84, the raw material supply amount can be adjusted.

The sand circulation amount can be controlled to be constant using the method described above.

Maintaining the combustion tower fluidized bed temperature constant can be carried out as follows.

As shown in FIG. 13, the bed temperature is measured with a thermometer 85 placed in the fluidized bed of the combustion tower, and based on the difference from the set temperature, the produced gas pipe 87 and the air pipe 88 are respectively This can be carried out by controlling the attached flow rate regulating valves 89 and 90 to change the combustion amount.

Here, if the sand circulation amount F _{S and} the combustion tower fluidized bed temperature T _RG are kept constant, the pyrolysis tower temperature T _RA can be easily kept constant by controlling the raw material supply amount _W. Even if the tower fluidized bed temperature _TRG is not kept constant, the objective can be achieved by controlling the raw material supply amount W, although there will be a time delay.

The second method is to control the amount of sand circulation so that the temperature of the fluidized bed in the pyrolysis tower remains constant.

In equation (4), Q _O changes due to changes in the properties of the pyrolysis raw material and changes in the supply amount. Furthermore, from equation (5), if the sand circulation amount F _S is changed to match the fluctuation of Q _O , the pyrolysis tower fluidized bed temperature T _RA can be kept constant. At this time, the combustion amount of the auxiliary burner is determined by the combustion tower fluidized bed temperature.
It may be controlled so that TR _RG is constant, or a constant amount of generated gas may be combusted.

However, in the latter case, when the sand circulation amount F _S is changed, the combustion tower fluidized bed temperature T _RG also changes, but the same effect can be achieved with the same operation, albeit with a time delay.

Examples will be described using drawings.

As shown in Fig. 14, the bed temperature is measured with a thermometer 91 placed in the fluidized bed of the pyrolysis tower, and based on the difference from the set temperature, the amount of sand circulation is determined by a command from the controller 92.
Control _FS . The method for controlling this sand circulation amount F _S is the method described above. That is, the control device 92 adjusts the ring air amount and the pumping air amount using the valves 51 and 51' to control the sand circulation amount F _S .

The third method is to control the amount of combustion in the auxiliary burner so that the pyrolysis tower fluidized bed temperature _TRA remains constant. In other words, since Q _O fluctuates due to changes in the properties and supply amount of the pyrolysis feedstock, the pyrolysis tower fluidized bed temperature T _RA can be kept constant by changing the combustion tower fluidized bed temperature T _RG accordingly. . At this time, it is desirable that the sand circulation amount F _S be constant, but F _S may be varied within a range where T _RA is constant in equation (5).

Examples will be explained using drawings.

As shown in FIG. 15, the bed temperature is measured with a thermometer 91 placed in the fluidized bed of the pyrolysis tower, and based on the difference between the bed temperature and the set temperature, it is attached to the produced gas pipe 87 and the air pipe 88, respectively, according to the command from the control device 93. This can be carried out by controlling the flow control valves 89 and 90 to change the combustion amount.

Common to all three methods, the following control may be added to the combustion control of the auxiliary burner. That is, the composition of the generated gas is analyzed by a gas chromatograph 94 or the like, the theoretical air amount is determined from the analyzed value, and the supplied air amount is controlled so as to keep the air-fuel ratio constant. This makes it possible to maintain stable combustion against fluctuating gas compositions.

Note that the waste contains low-melting point metals or low-melting point metal compounds such as aluminum Al and cadmium Cd, and these are contained in the gas discharged from the pyrolysis furnace and combustion furnace (hereinafter referred to as the "furnace"). Fine particles and vapors of low melting point substances are entrained. These low melting point substances are cooled on the inner surface of the flue and deposited on the cooling surface, including dust. If equipment such as a cyclone heat exchanger is located at the location where this precipitation occurs, the functionality of the equipment will be significantly reduced. In order to prevent problems caused by the precipitation of low melting point components, it is desirable to provide a precipitate removal device in the flue of gas discharged from the furnace. This precipitate removal device is
Shown in Figures 6A, 16B, and 16C. To explain this with reference to the drawings, a bent pipe 303 is provided immediately after the exhaust gas outlet generated at 301 or in the middle of the flue 302,
An opening 305 is provided in the middle of the curved pipe 303 on an extension in the direction of the inlet flow line, which includes the curved pipe inlet cross section.

A cylindrical or prismatic rotating body 304 is provided facing the opening 305 and serves as a cooling surface for solidifying and depositing a molten substance or precipitated substance mainly composed of aluminum, and the rotating body 304 is sealed from the outside air. A casing 319 is provided. Valves 308 and 310 are provided at the bottom of the casing 319.
A double discharge valve consisting of a discharge pipe 309 is provided, which is connected to a bunker 312 via a conveyance device 311 such as a transport pipe.

Since the flue 302 is made into a curved pipe 303, the exhaust gas discharged from the furnace 301 is removed from the rotating body 3 by inertia force.
04, and by selecting the surface temperature of the rotating body to be below the freezing point or below the precipitation point of the substance to be solidified or precipitated, it is possible to selectively attach it to the surface of the rotating body 304. It's like this.

Furthermore, by appropriately selecting the gas temperature, it is possible to condense high-boiling substances such as tar in the gas and use it as a binder to cause free carbon, dust, and chir in the gas to adhere to the surface of the rotating body.

Incidentally, since dust and chiar have no adhesion force to the rotating body 304, they do not adhere to the rotating body 304, but pass through the flue 302 together with the gas, and are configured to be collected by the cyclone 307 and discharged. .

A seal plate 324 may be provided protruding from the flue 302 or the casing 319 to prevent dust from clogging between the rotating body 304 and the casing 305. Furthermore, in order to keep the surface temperature below the freezing point, cooling water or cooling gas 316 is introduced into the rotating body 304 through the rotating shaft 315.
may be discharged from the outlet 317 after cooling. Further, the surface of the rotating body 304 may be subjected to a surface treatment such as Teflon treatment to weaken the adhesion of solidified matter or precipitates.

In the figure, 318 is a gasket, which is provided as a shaft seal to prevent gas from leaking into the atmosphere.

The rotary body 304 is driven by a low-speed electric motor 313 via a gear 314, a chain, or a belt, but instead of the rotary body 304, an endless belt may be freely hung and used as a moving cooling surface. . Furthermore, substances mainly composed of aluminum adhering to the rotating body 304 are scraped off by a scraping plate 306 fixed to the casing, discharged to the outside of the system by double discharge valves 308, 309, and 310, and transferred to a bunker by a transfer device 311. It is reasonable to store it in 312. 320 is a cooling water outlet, and 321 is a drain port. Furthermore, the opening 305 is connected to the bent pipe 303.
They may be directly formed, but it is also possible to use a joint pipe 323 with a flange 322, as shown by the dotted line in Figure 16B, to facilitate disassembly and connection. 324 is a seal plate.

The aluminum is then put into the furnace 301 as it is, and a part of it is discharged by the foreign matter discharge device already installed in the pyrolysis device, and a new aluminum removal device is installed in front of the cyclone to scrape and collect the aluminum adhering pieces.

Note that when the molten aluminum re-solidifies and adheres to the rotating body, the adhesion force can be weakened by finishing the surface of the rotating body.

That is, surface treatments include Teflon resin coating, enamel finishing, hard chrome plating, and the like. Among these, Teflon resin coating has chemical resistance at operating temperatures of 260°C or lower, and can be used even if there are some scratches on the surface.

On the other hand, if we look only at the gas discharged from the pyrolysis furnace, it is accompanied by the aforementioned low-melting-point substances, mainly aluminum, as well as oil and carbon, and these substances also adhere to the cooling surface of the flue and cause similar problems. adversely affect. Actual measurements of the temperature at which oil, carbon, etc. adhere to the cooling surface revealed that oil and carbon rapidly adhere to the cooling surface when the gas temperature drops below 350°C. Therefore, it is important to maintain the temperature of the gas passing through equipment such as a heat exchanger installed in the pyrolysis gas flue at 350°C or higher. However, it is difficult to maintain the pyrolysis gas at a temperature of 350°C or higher, and
When pyrolysis gas is placed in a gas holder for temporary storage, the temperature must be lowered to room temperature. Therefore, in handling the gas from the pyrolysis furnace, it is first treated with the precipitate removal equipment mentioned above, and the dust is separated with a dust collector.
Heat is recovered using a heat exchanger, and at this time, the gas temperature at the outlet of the heat exchanger is maintained at 350°C or higher, and then water or a chemical solution is sprayed to rapidly lower the gas temperature. Oil, carbon, etc. are removed by this water or It is preferable to separate the drug along with the drug solution. 17A, 17
This will be explained using figures B and 17C. 4 in Figure 17A
01 is a pyrolysis furnace, 430 is a combustion furnace 425, and a heat medium, ie, fluidized sand, is circulated between them.
The gas from the pyrolysis furnace 401 passes through a precipitate removal device (not shown), a cyclone 402, and then passes through a heat exchanger 4.
Leading to 03. There is a temperature detector 442 at the outlet of the heat exchanger 403. The pyrolysis gas exiting the heat exchanger 403 is brought into contact with water or a chemical solution in an absorption cooling tower 405, where it is cooled and harmful substances are removed. A part of the cooled gas is pressurized by a pressurizing device 419, guided to a heat exchanger 403, heated, and used as fluidizing gas for the pyrolysis furnace 401. The temperature of the pyrolysis gas decreases due to changes in the raw material for pyrolysis, and the detected value of the temperature detector 442 at the outlet of the heat exchanger 403 reaches 350°C.
In the following cases, the amount of fluidizing gas is lowered to lower the heat transfer load on the heat exchanger 403. This reduces the release of heat from the pyrolysis furnace 401 by the fluidizing gas, and also leads to increasing the temperature of the pyrolysis furnace 401.

Alternatively, it is also effective to increase the amount of gas in the auxiliary burner 435 of the combustion furnace 430 to raise the temperature of the combustion furnace 430, and to raise the temperature of the heat medium flowing into the pyrolysis furnace 401, and these two means may be used alone or in combination. It is desirable to do this at the same time.

However, the amount of fluidizing gas must be within the range of gas flow rate determined in advance by the heat medium, and
The temperature inside the combustion furnace should also be kept within a range that does not melt the heat transfer medium.

In addition, in FIG. 17A, FIG. 17B, and FIG. 17C, 404 is a recirculation line, 406 is a reuse process, 407 is a pump, 408 is a cooler, and 409
is an inflow part, 410 is a pump, 411 is an alkali tank, 412 is an absorption/drainage liquid, 413 is an oil separator, 4
14 is an oil pipe, 415 is a drainage pipe, 416 is a dust pipe, 420 is a waste, 421 is a supply device, 42
2 is a heat exchanger outlet, 423 is a heat exchanger inlet, 424 is an absorption cooling tower inlet, 431 is a dust collector, 432 is a heat exchanger, 433 is a rear end device, 441 is air, 443 is a control device, 444 is a fuel adjustment valve, 451, 45
2,453 is a liquid injection part, 454 is a rectifying plate, 455 is an inner wall, and 456 is a mist separator.

In the above embodiment, the thermal decomposition temperature is brought to a predetermined temperature by controlling at least one of the following: controlling the raw material supply amount W, controlling the fluidized medium circulation amount F _S , or controlling the burner combustion amount. None, the composition and amount of produced gas are stably controlled.

According to the present invention, the level of the fluidized medium in the fluidized bed combustion tower can be adjusted with rapid response to changes in the conditions of the raw material, and the level of the fluidized medium can be quickly secured, and the flow of the fluidized medium can be controlled stably. , it is possible to provide a stable and reliable pyrolysis method by adjusting the pyrolysis temperature and stabilizing the quality of the produced gas without fear of operation interruption, and has extremely great practical effects. .

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between pyrolysis temperature and gas production amount, Figure 2 is a diagram showing the relationship between pyrolysis temperature and generated gas composition, and Figures 3 to 17C are diagrams showing the relationship between pyrolysis temperature and gas production amount. Regarding an example, Fig. 3 is a flow sheet of a two-column circulation type pyrolysis equipment, Fig. 3A and Fig. 3B.
The figures are flow diagrams of different examples of foreign matter evacuation devices, Figure 3C is a flow diagram of the combustion furnace and pyrolysis furnace parts, Figures 3D and 3E are plan views and vertical sectional views of the vicinity of the pipe grid, and Figure 3F. , Figure 3G,
Fig. 3H is a plan view of different examples of pipe grids, Fig. 4 is a diagram showing the relationship between sand filling amount and tower top differential pressure, Fig. 5 is a flow diagram of the sand filling amount control device, and Fig. 6 7 is a flow diagram of the sand circulation amount control device.
The figure is a vertical cross-sectional view of the vicinity of the nozzle of the pumping part, Figure 8 is a vertical cross-sectional view of another example of the nozzle part, and Figure 9 is a line showing the relationship between the fluidization ring supply air amount and the heat medium circulation amount. 10 is a flowchart of the pyrolysis tower superficial velocity control device and the differential pressure control device between the tops of the tower. Flow sheet for integrated control of top-to-top differential pressure control,
Figures 11A and 11B are diagrams showing the operating ranges of different examples, Figures 12 and 12A are flow diagrams of different examples of the raw material supply device, and Figure 13 is a diagram of the combustion tower fluidized bed temperature control device. flow diagram,
Fig. 14 is a flow diagram of a pyrolysis temperature control device using sand circulation amount control, Fig. 15 is a flow diagram of an auxiliary burner combustion amount control device, and Fig. 16A is a cutaway plan view of a device for removing low melting point metals such as aluminum. , 1st
Figure 6B is a longitudinal sectional view of the same, Figure 16C is a side view of one state of use, Figure 17A is an overall flow diagram of the device for removing adhesive substances such as carbon, and Figure 17B is a diagram of the absorption cooling tower related system. Flow diagram, Figure 17C is a detailed flow diagram of the absorption cooling tower. 1... Pyrolysis tower, 2... Combustion tower, 3... Conveyor, 4... Silo, 5... Supply hopper, 6... Refuse feeder, 7... Lifting section, 8... Pyrolysis tower flow layer, 9... collection device, 10... chir supply device,
11... Combustion tower fluidized bed, 12... Water treatment equipment, 1
3... Aluminum removal machine, 14... Collection device, 15...
... Heat exchanger, 16 ... Gas cleaning device, 17 ... Gas holder, 18 ... Blower, 19 ... Heat exchanger, 20 ... Heat exchanger, 21 ... Dust collector, 22 ...
...Chimney, 23, 24, 25... Foreign matter discharge device, 2
6... Foreign matter/sand separation device, 27, 28... Conveyor, 29... Hopper, 30... Foreign matter bunker, 31
... Bunker, 32 ... Quantitative feeder, 33 ... Discharge device, 34, 35, 36 ... Supply pipe, 37 ...
Rotary feeder, 38... Valve, 39... Sand level detector, 40, 41'... Sand level detector, 41... Control mechanism, 42, 43... Differential pressure detector, 44... Nozzle, 45 ...Lifting pipe, 46...Ratsupa-shaped entrance,
47... Jet nozzle, 48... Surface, 49... Fluidization ring, 50... Flow meter, 51, 51'... Valve, 5
2... Fumarole, 53, 54... Measurement hole, 55...
Differential pressure detector, 56... Control mechanism, 57... Pressure difference detector, 58, 59... Tower top, 60... Pressure detector, 61... Control mechanism, 62... Valve, 63...
Control mechanism, 64... Valve, 65... Pressure detector, 6
6... Blower, 67... Flow meter, 68... Control mechanism, 69... Flow control valve, 70... Temperature detector,
71...Taper screw feeder, 72...
Crushing machine, 73... Straight screw feeder, 74... Intermediate chamber, 75... Taper part, 76
...Shoot, 77...Return conveyor, 78...
Hinge, 79, 79'... Lid, 80, 80'...
Cylinder, 81... Chute, 82... Level detector, 83... Fluidized bed, 84... Control device, 85
... Thermometer, 86 ... Control device, 87, 88 ...
Piping, 89, 90...flow control valve, 91...thermometer, 92, 93...control device, 94...gas chromatograph, 101...pyrolysis furnace, 102...floor plate, 103...foreign matter discharge pipe, 104...Inlet,
105...Underfloor room, 106...Blower, 107...
...Inlet, 108...Fluidized bed, 109...Valve, 1
11...Inlet, 112...Valve, 113...Steam source, 115,116...Valve, 117...Cooling device, 118...Drain outlet, 119,120,
121... Valve, 122... Differential pressure detector, 124...
... Combustion tower, 125 ... Control mechanism, 126 ... Lifting section, 201 ... Pyrolysis furnace, 202 ... Combustion furnace, 2
03...Storage tank, 204,205...Communication pipe, 20
6... Lifting pipe, 207... Nozzle, 208... Bottom, 209... Burner, 210... Discharge port, 21
1... Gas distribution plate, 212... Gas chamber, 213...
... Foreign matter discharge pipe, 214, 215 ... Inlet, 21
6...Feeder, 217...Discharge port, 218...
Valve, 219... Foreign matter discharge device, 220... Gas distribution plate, 221... Gas chamber, 222... Inlet, 2
23...Exit, 224...Pipe grid, 22
5...Blowout hole, 226...Pipe, 301...
Furnace, 302... Flue, 303... Bent pipe, 304...
... Rotating body, 305 ... Opening, 306 ... Scraping plate, 307 ... Cyclone, 308 ... Valve,
309...Discharge pipe, 310...Valve, 311...
...transport device, 312...bunker, 313...low-speed electric motor, 314...gear, 315...rotating shaft,
316...Cooling gas, 317...Outlet, 318...
...Patzkin, 319...Casing, 320...
Outlet, 321...Discharge port, 322...Flange, 323...Joint pipe, 324...Seal plate, 4
01...Pyrolysis furnace, 402...Collection device, 403
... Heat exchanger, 405 ... Absorption cooling tower, 406 ...
... Reuse process, 407 ... Pump, 408 ... Cooler, 409 ... Inflow section, 410 ... Pump, 4
11...Alkali tank, 413...Oil separation tank,
414... Oil, 415... Water treatment equipment, 419
... Pressure device, 421 ... Supply device, 422 ...
Exit, 424... Inlet, 425... Connecting pipe, 43
0... Combustion furnace, 431... Dust collection device, 43
2... Heat exchanger, 433... Rear end equipment, 435...
...Auxiliary combustion burner, 441...Air, 442...Temperature detector, 443...Control device, 444...Fuel control valve, 451, 452, 453...Injection point, 45
4... Rectifier plate, 455... Inner surface, 456... Mist separator.

Claims (1)

[Scope of Claims] 1. A fluidized bed pyrolysis tower, a fluidized bed incineration tower, a connecting pipe that leads the fluidized medium in the fluidized bed pyrolysis tower to the fluidized bed pyrolysis tower, and a fluidized bed pyrolysis tower that leads the fluidized medium in the fluidized bed pyrolysis tower to the fluidized bed pyrolysis tower. It is equipped with a communication pipe leading to the pumping section, a pumping pipe leading the fluidized medium stored in the pumping section to the fluidized bed incineration tower, and a waste feeder that supplies solid waste to the fluidized bed pyrolysis tower. In a two-column circulation type pyrolysis method that pyrolyzes organic raw materials such as waste, a supplementary fluidized medium is supplied to the fluidized bed incineration tower, the fluidized media levels in the pyrolysis tower and the incineration tower are detected, and this signal is detected. The filling amount of the fluidized medium is controlled by manipulating either the fluidized medium supply amount or the foreign matter discharge amount of the pyrolysis tower or the incineration tower based on the pressure difference between the tops of the pyrolysis tower and the incineration tower or the pressure difference between the tops of the pyrolysis tower and the incineration tower, or the pressure difference between the tops of the pyrolysis tower and the incineration tower, or the pressure difference between the towers. Detecting a deviation in the fluidizing medium level of both columns based on the difference in the fluidizing medium level of the two columns, and adjusting the top pressure of the column by controlling the opening of a valve provided in the pyrolysis gas outlet path, or It is controlled by adjusting the circulation amount of the fluidized medium, and also detects the temperature of the pyrolysis tower and the temperature of the incineration tower, and controls the combustion amount of the auxiliary burner in the incineration tower, the circulating amount of the fluidized medium, or the amount of waste supplied. 1. A thermal decomposition method characterized in that the temperature of both columns is controlled to be within a predetermined range.