JP2006098026A - Pyrolyzing treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pyrolyzing treatment system capable of exhibiting waste treating capacity to the maximum even with the occurrence of a heating impediment factor such as adhesion. <P>SOLUTION: In the pyrolyzing treatment system for pyrolyzing a treated material 1 into pyrolyzed gas 6 and pyrolyzed residue 7 by heating it in a pyrolyzing furnace 3, the heating value of a heating source to the pyrolyzing furnace is measured by a heat source heating value measuring means, and the quantity of exhaust heat exhausted after heating the pyrolyzing furnace 3 is measured by an exhaust heat measuring means 12. The difference between the heating value of the heat source and the quantity of exhaust heat is obtained by a control device 13, and the net quantity of heating to the treated material is obtained from the difference. The treated quantity of the treated material to the heating furnace 3 is adjusted corresponding to the net quantity of heating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal decomposition treatment system that heats an object to be processed in a thermal decomposition furnace to thermally decompose it into a pyrolysis gas and a pyrolysis residue.

  As a waste treatment system that transforms unsorted and untreated waste containing various pollutants (processed materials) into usable materials, a thermal decomposition treatment system that thermally decomposes waste has been conventionally used. It is known (see, for example, Patent Document 1).

  This thermal decomposition treatment system is a system in which waste containing organic matter is heated to several hundred degrees Celsius in a reducing atmosphere to decompose it into thermal decomposition gas and solid residue. As such a thermal decomposition treatment system, an external heating type rotary furnace (kiln) that employs an external heating method for heating the rotary drum from the outside can be applied. Externally heated kilns have a long history of use in cement firing, etc., and are generally widely used as undecomposed and unsorted waste disposal devices with a simple structure and high reliability.

  In this thermal decomposition processing system, waste is introduced into the rotary drum (rotary furnace) by an input device having a weighing function. A combustion chamber is formed outside the rotating drum, in which fuel is burned by a burner or the like, and waste is heated through the rotating drum. The waste in the heated rotating drum is pyrolyzed into pyrolysis gas and solid pyrolysis residue, and discharged individually from the respective outlets. Further, the combustion exhaust gas from the combustion chamber is discharged out of the system through the exhaust duct. The pyrolysis gas and solid residue generated from the waste are sent to various processing apparatuses in the post-process of the pyrolysis processing system and subjected to detoxification, and then reused as an energy source.

  In the thermal decomposition treatment system as described above, it is desirable that the thermal decomposition treatment of an object to be treated such as waste is performed stably and continuously over a long period of time. However, if the thermal decomposition treatment of the workpiece is continuously performed for a long time in the rotary drum of the pyrolysis furnace, the thermal decomposition residue adheres to the inner wall of the rotary drum and the processing capacity is lowered. There is a problem. That is, the thermal decomposition residue adhering to the inner wall of the rotating drum blocks the heat transferred from the outside of the rotating drum to the inside. Therefore, in the method of heating the workpiece in the rotating drum from the outside of the rotating drum, Heat from heating is not sufficiently transferred to the inside of the rotating drum. As a result, the heat transfer efficiency deteriorates, it becomes difficult to efficiently thermally decompose the object to be processed in the rotating drum, the object to be processed cannot be heated to a predetermined thermal decomposition temperature, and the processing amount is reduced. This is because it must be lowered.

  In order to solve such a problem, a device for mechanically scraping off deposits on the inner wall of the drum while continuing the processing operation has been proposed. Also in this case, it is difficult to completely prevent deposits from being deposited, and when an externally heated rotary drum is applied to thermal decomposition, the problem of performance degradation due to adhesion is inevitably generated. .

  Generally, the heating state of the workpiece is controlled by monitoring the temperature inside or outside the drum, or by the temperature of the workpiece to be processed at the outlet. When the heat transfer is deteriorated by the deposit and the temperature inside the drum or at the outlet is lowered, generally, a measure is taken to increase the heating amount or to reduce the processing amount.

Here, increasing the heating amount naturally has an upper limit value from the heat resistance of the device and the capacity of the heating device, and after reaching this upper limit, there is only an option for a decrease in the processing amount. On the other hand, it is difficult to accurately measure the temperature inside the drum when deposits are accumulated, and it is difficult to determine whether heating is appropriate for the pyrolysis process. Will be difficult. For this reason, it must be operated with a low throughput.
JP 2000-202419 A

  In this way, if deposits are generated on the inner wall of the pyrolysis furnace, it is difficult to accurately grasp the amount of heat applied to the object to be processed in the pyrolysis furnace, and the performance is drawn up to the maximum capacity of the pyrolysis furnace. It was difficult to perform efficient processing.

  An object of the present invention is to provide a thermal decomposition treatment system capable of maximizing the waste treatment capacity even when a heating inhibiting factor such as adhesion occurs.

  The thermal decomposition processing system of the present invention is a thermal decomposition processing system that heats an object to be processed in a thermal decomposition furnace and decomposes it into a thermal decomposition gas and a thermal decomposition residue. The heat quantity metering means of the heating source to be metered, the exhaust heat quantity metering means for metering the amount of exhaust heat exhausted after heating the pyrolysis furnace, and the difference between the heat quantity of the heat source measured by these metering means and the amount of exhaust heat. And a control device for obtaining a net heating amount for the processing object and adjusting a processing amount of the object to be processed in the heating furnace in accordance with the net heating amount.

  Further, in the present invention, a fuel flow meter to the heating source is provided as a calorific value measuring means of the heating source, and the heating source is calculated from the fuel consumption measured by the fuel flow meter and the calorific value of the fuel determined in advance. The amount of heat is being sought.

  Further, in the present invention, an exhaust gas thermometer is provided as the exhaust heat quantity measuring means, and the exhaust gas temperature measured by the exhaust gas thermometer, the exhaust gas flow rate obtained from the fuel consumption amount and the preset air ratio, The amount of exhaust heat is calculated from these.

  Furthermore, in the present invention, an external combustion type rotary furnace is used as the pyrolysis furnace.

  According to the present invention, even if a heating-inhibiting factor such as adhesion due to the progress of processing occurs, the net amount of heat inside the drum (pyrolysis furnace) can be known almost accurately, so that it corresponds to the state of the drum. It is possible to select the optimum processing amount and control the input amount, and to maximize the waste processing capacity.

  Hereinafter, an embodiment of a thermal decomposition treatment system according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the overall configuration of this embodiment. As described above, the thermal decomposition treatment system heats waste containing organic substances to several hundred degrees Celsius in a reducing atmosphere to separate into pyrolysis gas and solid residue. As the pyrolysis furnace, an externally heated rotary furnace (kiln) that employs an external heating method for heating the rotary drum from the outside is used.

  In FIG. 1, waste 1 is charged into a rotating drum 3 by a charging device 2 having a weighing function, and is heated by a combustion chamber 4 provided outside the rotating drum 3. That is, in the combustion chamber 4, the fuel 10 is burned by the burner 5, and the waste in the rotating drum 3 is heated via the rotating drum 3 by the combustion heat. The waste in the heated rotating drum 3 is pyrolyzed into pyrolysis gas 6 and solid pyrolysis residue 7 and discharged from the outlet. Further, the combustion exhaust gas 8 from the combustion chamber 4 is discharged out of the system through the exhaust duct 9. The pyrolysis gas 6 and the solid residue 7 generated from the waste are reused as an energy source after being sent to various processing apparatuses in the post-process of the pyrolysis treatment system and subjected to detoxification treatment.

  In this embodiment, an external combustion type rotary furnace having a rotary drum 3 is used as the pyrolysis furnace. The heating source for the rotary drum (pyrolysis furnace) 3 is the burner 5 of the combustion chamber 4 as described above, and the fuel flow rate to the fuel supply path to the burner 5 as a calorific value measuring means of the heating source for measuring the amount of heat. A total of 11 is provided to measure the amount of fuel 10 consumed. An exhaust gas thermometer 12 is provided in the exhaust path of the exhaust gas 8 as an exhaust heat amount measuring means for measuring the exhaust heat amount after heating the rotary drum 3 to measure the exhaust temperature.

  Further, a control device 13 is provided that performs calculation using these pyrolysis furnace operation state quantities as input, and allows the input amount of the waste 1 to be adjusted by the input device 2.

  The control device 13 calculates the total heat input to the pyrolysis furnace from the fuel consumption measured by the fuel flow meter 11, calculates the exhaust gas flow rate, and from the exhaust gas flow rate and the exhaust gas thermometer 12, Calculate the amount of heat exhausted outside the pyrolysis furnace system.

  That is, first, the amount of heat input to the combustion chamber 4 as a heating source (total amount of heat input to the pyrolysis furnace) from the fuel consumption measured by the fuel flow meter 11 and the calorific value of the fuel 10 determined in advance. Is obtained by the following equation.

(Total heat input to the pyrolysis furnace) = (Fuel consumption) x (Fuel exotherm)
Here, the calorific value of the fuel is already known from the composition of the fuel.

  Next, the exhaust gas flow rate is obtained from the exhaust gas temperature measured by the exhaust gas thermometer 12, the fuel consumption measured by the fuel flow meter 11, and the preset air ratio of the burner 5, and the exhaust heat amount is obtained therefrom. Ask for.

  Although the calculation of the exhaust gas flow rate is complicated, it can be calculated by using a fuel consumption amount and an “air ratio” that are preset by adjusting the burner. The air ratio is usually a constant value set during the plant trial operation.

  Details are shown below. This relational expression is very common in a heating system by combustion of fuel using liquid or gas.

Exhaust gas flow rate G: actual exhaust gas amount per fuel 1kg or 1Nm ³ Nm ³ / kg
_{G = G 0 + (m-} 1) A 0 + G W + G W '[Nm 3 / kg] or [Nm 3 / Nm 3]
here,
m: Air ratio [-]
G ₀ : Theoretical dry exhaust gas amount [Nm ³ / kg] or [Nm ³ / Nm ³ ]
A ₀ : Theoretical air combustion amount [Nm ³ / kg] or [Nm ³ / Nm ³ ]
G _W: amount of water vapor in the exhaust gas due to moisture vapor and fuel caused by the combustion
[Nm ³ / kg] or [Nm ³ / Nm ³ ]
_w ': Amount of water vapor in exhaust gas depending on combustion air temperature [Nm ³ / kg] or [Nm ³ / Nm ³ ]
_{G W '= 1.61zmA 0 [Nm} 3 / kg] or [Nm 3 / Nm 3]
z: Absolute humidity of outside air [kg / (kg dry air)], but Z may be set to 0 in the approximate calculation.

In order to estimate the value of the theoretical air combustion amount A _o and the theoretical exhaust gas amount G ₁ = G _o + G _w including water vapor, it is obtained from the following empirical formula using the lower heating value H _l of the fuel.

In the case of gaseous fuel and high calorific value (H _l > 14.65 × 10 ⁶ J / Nm ³ ) A ₀ = 1.105H _l /4.1868×10 ⁶ +0.2 [Nm ³ / Nm ³ ]
G ₁ = 1.19H _l /4.1868×10 ⁶ +0.5 [Nm ³ / Nm ³ ]
The net amount of heat input to the waste inside the rotary drum 3 is determined as the amount of exhaust heat subtracted from the total amount of heat input. Further, the input amount control device 13 calculates the optimum input amount from the net heat input amount to the waste thus obtained, and controls the input device 2.

  Here, the net heat input is obtained in an optimum operation method when the temperature of the waste in the rotary drum 3 is not accurately known, and the waste is sufficiently heated to a predetermined thermal decomposition temperature (for example, 550 ° C.). As shown in the figure, the optimum input amount is obtained by the following equation.

(Net heat input) = (Waste input amount) x (Waste specific heat) x (Predetermined thermal decomposition temperature-Waste temperature before input (= normal temperature))
From this, the optimum input amount is as shown in the following equation.

(Optimum input amount) = (net heat input amount) / {(specific heat of waste) × (predetermined thermal decomposition temperature−waste temperature before input (= normal temperature))}
As described above, in the present embodiment, even if a heat transfer inhibiting factor such as an adhering matter is generated inside the rotating drum 3 as the waste processing progresses, the net heating amount inside the rotating drum 3 is reduced. In the control device 13, the actual heating state can be diagnosed almost accurately, and it is possible to control the processing amount to an optimum amount according to the heating state.

  In other words, even if there is a heating-inhibiting factor such as adhesion due to the progress of processing, the net heating amount inside the drum can be known almost accurately, so the optimum processing amount according to the drum state is selected and input. The amount can be controlled, and the waste processing capacity can be maximized.

1 is an overall configuration diagram showing an embodiment of a thermal decomposition system according to the present invention.

Explanation of symbols

1 Waste (processed material)
3 Pyrolysis furnace (rotary drum)
5 Heating source (burner)
6 Pyrolysis gas 7 Pyrolysis residue 8 Exhaust gas 10 Fuel 11 Heat source heat quantity metering means (fuel flow meter)
12 Waste heat measurement means (exhaust gas thermometer)
13 Control device

Claims (4)

A pyrolysis processing system that heats a workpiece in a pyrolysis furnace and pyrolyzes it into pyrolysis gas and pyrolysis residue,
A heat quantity metering means for measuring the heat quantity of the heating source for the pyrolysis furnace, and an exhaust heat quantity measuring means for measuring the amount of exhaust heat exhausted after heating the pyrolysis furnace;
The net heating amount for the object to be processed is obtained from the difference between the heat amount of the heating source measured by these measuring means and the exhaust heat amount, and the processing amount of the object to be processed in the heating furnace is adjusted in accordance with the net heating amount. A control device;
A thermal decomposition treatment system comprising:   A fuel flow meter to the heating source is provided as a means for measuring the heat amount of the heating source, and the heat amount of the heating source is obtained from the fuel consumption measured by the fuel flow meter and the calorific value of the fuel obtained in advance. The thermal decomposition processing system according to claim 1.   An exhaust gas thermometer is provided as a means for measuring the amount of exhaust heat, and the exhaust gas temperature measured by the exhaust gas thermometer and the exhaust gas flow rate obtained from the fuel consumption and a preset air ratio are used. The thermal decomposition processing system according to claim 2, wherein the amount of heat is obtained.   The pyrolysis treatment system according to any one of claims 1 to 3, wherein an external combustion type rotary furnace is used as the pyrolysis furnace.

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