JP2011021834A - Method of controlling vapor content in waste melting furnace and vapor content control device for waste melting furnace facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress fluctuation of vapor content by controlling scattering amounts of a combustible gas and char after thermal decomposition, through detection of a thermal decomposition state in a waste melting furnace by selecting a fluctuation state of the highest fluctuation speed among fluctuation states of the waste melting furnace, and through adjustment of an amount of air distributed to a tuyere. <P>SOLUTION: The vapor content of the waste melting furnace facilities is controlled, the facilities which are constituted to treat an exhaust gas after recovering sensible heat by an exhaust gas treatment device 7 in a boiler 6 recovering the sensible heat of the exhaust gas generated in a combustion chamber 5 for burning the combustible gas and combustible residue generated in the waste melting furnace 1, and discharging the exhaust gas after the treatment from a chimney 9 through an induced draft fan 8. A waste charging level 14 in the waste melting furnace, a vapor generation amount 15 in the boiler, an operation load 16 of the induced draft fan, and an exhaust gas amount 17 in an outlet of the chimney are measured, and supply amounts of oxygen source from tuyeres 3, 4 are adjusted on the basis of the measurement value of highest fluctuation value among results of the measurements to control the vapor generation amount in the boiler 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the waste melting furnace processing facility, the present invention burns combustible gas and combustible residue (char) generated from a waste melting furnace for melting waste in a combustion chamber, and generates steam from the exhaust gas after combustion. The present invention relates to the control of the steam amount of a boiler that recovers heat.

  An exhaust gas containing combustible gas and char generated when general waste, industrial waste, shredder dust and other waste are melted in the waste melting furnace is a combustion chamber installed at the rear stage of the waste melting furnace The combustion exhaust gas that is introduced into and burned into the exhaust gas is recovered by a boiler (see Patent Documents 1 and 2).

  Since the waste quality of the waste introduced into the waste melting furnace is not constant and fluctuates, the combustible gas components and the amount of char in the exhaust gas discharged from the waste melting furnace fluctuate. For example, when waste containing a small particle size, such as waste containing plastic such as automobile shredder dust (ASR), and containing a large amount of plastics, which is susceptible to rapid thermal decomposition, is put into a waste melting furnace and processed. Later combustible gas and char are scattered and introduced into the combustion chamber, and the temperature of the combustion chamber rises rapidly. When the temperature of the combustion chamber rose rapidly, the evaporation amount in the boiler at the rear stage of the combustion chamber was greatly fluctuated.

JP-A-8-94035 JP-A-8-159436

  Conventionally, when the pyrolysis combustible gas and char discharged from the waste melting furnace increased rapidly, and the boiler steam volume increased significantly, it was handled by operator operation, so the fluctuation range was too large to follow the fluctuation. If not, the boiler steam temperature upper limit was exceeded, leading to an emergency shutdown of the plant.

  Therefore, the present invention selects the fastest change from the fluctuation state of the waste melting furnace, quickly detects the thermal decomposition state in the waste melting furnace, and adjusts the amount of air blown to the tuyere accordingly Thus, the present invention provides a steam amount control method and apparatus for a boiler of a waste melting furnace facility that controls the amount of scattered flammable gas and char after pyrolysis to suppress fluctuations in the amount of steam.

  According to the first aspect of the present invention, waste is introduced from the upper part of the furnace, and an oxygen source is supplied from a plurality of tuyere arranged at the lower part of the furnace to melt the ash and non-combustibles in the waste. , Flammable gas generated in a waste melting furnace that discharges molten material from the bottom of the furnace, combustion chamber that burns flammable residue, boiler that recovers sensible heat of exhaust gas generated in the combustion chamber, and exhaust gas after sensible heat recovery in the boiler In a method for controlling the amount of steam in a waste melting furnace facility comprising a chimney that is processed by an exhaust gas treatment device and exhausts the treated exhaust gas through an induction fan, the waste filling level in the waste melting furnace, boiler The amount of steam generated, the operating load of the induction fan and the amount of exhaust gas at the smoke outlet are measured, and the oxygen source supply amount from the upper tuyere is adjusted based on the measured value with the largest variation of these measurement results. Controlling the amount of steam generated in the boiler To.

  According to the second aspect of the present invention, waste is introduced from the upper part of the furnace, and an oxygen source is supplied from a plurality of tuyeres arranged in the lower part of the furnace to melt the ash and non-combustibles in the waste. A waste melting furnace for discharging the melt from the bottom of the furnace, a combustion chamber for burning the combustible gas and combustible residue generated in the waste melting furnace, a boiler for recovering sensible heat of the exhaust gas generated in the combustion chamber, and a boiler In the steam control equipment of the waste melting furnace facility composed of an exhaust gas treatment device for exhaust gas after sensible heat recovery and a chimney that discharges the treated exhaust gas through an induction fan, the waste installed in the waste melting furnace A filling level measuring device for measuring the filling level of waste in the melting furnace, a generated steam amount measuring device for measuring a generated steam amount of a boiler installed in the boiler, and an attraction for measuring an operating load of the induction fan Ventilator operating load measuring device and the smoke The exhaust gas amount measuring device that measures the exhaust gas amount at the outlet of the air and the measurement results from each of the measuring devices are input, and the air flow rate to the tuyere is calculated based on the measured value with the largest fluctuation value of these measurement results And an air supply control device that outputs a control signal for adjusting the opening degree of the valve to a flow rate adjusting valve that adjusts the amount of air sent to the tuyere.

  In the present invention, when pyrolysis progresses rapidly, there is a sudden decrease in the dust level, a rapid increase in the amount of boiler steam, a sudden increase in the operating load of the induction fan, and a rapid increase in the exhaust gas flow rate. Measure the filling level, the amount of steam generated from the boiler, the load of the induction fan and the amount of exhaust gas from the smoke outlet, and the pyrolysis status in the melting furnace based on the measured value with the largest fluctuation value of any of the detection end data Can be adjusted at the time before the fluctuation of the boiler steam volume becomes large, and the boiler steam volume can be maintained within an appropriate range. It becomes. In addition, it is possible to reliably suppress fluctuations in the boiler steam amount by adjusting the air flow rate while maintaining the air flow balance that can maintain the stable melting state of the waste melting furnace.

1 is a schematic overall view of a waste melting furnace facility to which a steam amount control method of the present invention is applied. The arrangement | positioning of the upper tuyeres of the melting furnace by this invention is shown, (a) is an upper stage tuyeres of AA, (b) is an arrangement plan of the middle tuyeres of BB. It is a graph which shows the relationship between the air quantity and boiler steam quantity of an upper stage tuyere and a middle stage tuyere.

  Embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, coke is charged from the upper part of the shaft furnace type waste melting furnace 1 together with waste and auxiliary limestone. Air is blown from an upper tuyere composed of an oxygen-containing gas or an oxygen-enriched gas and a middle tuyere 3 and an upper tuyere 4 above the lower tuyere 2 at the bottom of the furnace. The carbonaceous material generated by coke and pyrolysis is burned at a high temperature in the high-temperature hearth, and the drying zone, pyrolysis zone, and combustion melting zone in the furnace are sequentially lowered to form molten slag.

  The exhaust gas containing the combustible gas and char discharged from the melting furnace 1 is combusted in the combustion chamber 5, the high-temperature combustion exhaust gas is recovered by the boiler 6, and the exhaust gas from the boiler 6 is used as a cooling tower of the exhaust gas treatment facility 7. Then, it is neutralized with a neutralizing agent such as slaked lime, solid-gas separated by a dust collector, and discharged from the chimney 9 through the induction fan 8. The waste melting furnace 1, the combustion chamber 5, the boiler 6, the exhaust gas treatment facility 7, and the induction ventilator 8 are sequentially connected by ducts 10 to 13, respectively.

  The melting furnace 1 is provided with measuring devices 14 to 17 for measuring the dust level, the boiler for the amount of boiler steam, the induction fan for operating load (current value), and the exhaust gas flow rate for the outlet of the chimney. .

  The upper tuyere of the melting furnace 1 is shifted in the circumferential direction of the melting furnace 1 so that the upper tuyere 4 shown in FIG. 2A and the middle tuyere 3 shown in FIG. By arranging it, the amount of air blown is made to flow uniformly without being biased in the furnace.

  The upper tuyere 4, the middle tuyere 3 and the lower tuyere 2 are respectively connected to the upper tuyere header 20, the middle tuyere header 21 and the lower tuyere header 22 branched from the oxygen source supply pipe 19 of the blower 18. Air is supplied from the connected upper tuyere air supply pipe 23, middle tuyere air supply pipe 24, and lower tuyere air supply pipe 25. The air supply pipes 23, 24, 25 are provided with flow rate adjusting valves 26, 27, 28, respectively.

  Measurement signals measured by the measurement devices 14 to 17 are input to the air supply control device 29, and flow rate control signals are output to the flow rate adjustment valves 26 and 27. The air supply control device 29 includes an adjustment amount of an individual flow rate control valve for each of the upper tuyere 4 and the middle tuyere 3 with respect to the fluctuation level of the dust level, the boiler steam amount, the induction fan load or the exhaust gas flow rate of the chimney. Is set, and the set value of the adjustment amount of the flow rate control valve is output as a control signal to the flow rate control valve with respect to the measured dust level, boiler steam amount, induction ventilator load or chimney exhaust gas flow rate.

  As shown in the graph of FIG. 3B, among the measurement signals of the dust level, boiler steam amount, induction ventilator load or chimney exhaust gas flow rate input to the air supply control device 29, the thermal decomposition in the melting furnace. If the measurement signal selected the fastest is the boiler steam amount 30, the temperature control device 29 responds to the settings of the upper tuyere blown air amount 31 and the middle tuyere blown air amount 32, respectively. The control signal of the adjustment amount of each flow regulating valve 4 and 3 is output and is adjusted to be reduced, so that an increase in the boiler steam amount 30 is suppressed.

Thermal decomposition in the melting furnace occurs when either (1) a sharp drop in dust level, (2) a rapid increase in boiler steam volume, (3) a sudden increase in operating load of the induction fan, or (4) a sudden increase in exhaust gas flow rate Therefore, when any detection signal is input to the air supply control device, the flow adjustment valve at the upper tuyere or the middle tuyere is adjusted to reduce the amount of blown air and to quickly perform thermal decomposition. suppress. By this suppression, the fluctuation range of the boiler steam amount is not increased, and the fluctuation of the boiler steam amount can be surely suppressed.

1: Melting furnace 2: Lower tuyere 3: Middle tuyere 4: Upper tuyere 5: Combustion chamber 6: Boiler 7: Exhaust gas treatment equipment 8: Induction ventilator 9: Chimney 10-13: Duct 14: Measuring device (garbage) level)
15: Measuring device (boiler steam volume)
16: Measuring device (attracting ventilator load)
17: Measuring device (exhaust gas flow rate)
18: Blower 19: Oxygen source supply pipe 20: Upper tuyere header 21: Middle tuyere header 22: Lower tuyere header 23: Upper tuyere air supply pipe 24: Middle tuyere air supply pipe 25: Lower tuyere Mouth air supply pipe 26: Flow rate adjustment valve 27: Flow rate adjustment valve 28: Flow rate adjustment valve 29: Air supply control device 30: Boiler steam amount 31: Upper tuyere blown air amount 32: Middle stage tuyere blown air amount

Claims (2)

Disposal in which waste is introduced from the top of the furnace, oxygen sources are supplied from a plurality of tuyeres arranged at the bottom of the furnace, ash and non-combustibles in the waste are melted, and the melt is discharged from the bottom of the furnace Combustion gas that burns combustible gas and combustion residue generated in a material melting furnace and boiler that recovers sensible heat of exhaust gas generated in the combustion chamber In the method for controlling the amount of steam in a waste melting furnace facility comprising a chimney that discharges the exhaust gas through an induction ventilator,
Measure the filling level of waste in the waste melting furnace, the amount of steam generated by the boiler, the operating load of the induction fan and the amount of exhaust gas from the smoke outlet,
The steam of the waste melting furnace equipment is characterized in that the amount of steam generated in the boiler is controlled by adjusting the oxygen source supply amount from the upper tuyere based on the measurement value having the largest fluctuation value of these measurement results. Quantity control method. Disposal in which waste is introduced from the top of the furnace, oxygen sources are supplied from a plurality of tuyeres arranged at the bottom of the furnace, ash and non-combustibles in the waste are melted, and the melt is discharged from the bottom of the furnace Waste melting furnace, combustion chamber for burning combustible gas and combustible residue generated in waste melting furnace, boiler for recovering sensible heat of exhaust gas generated in combustion chamber, and exhaust gas treatment of exhaust gas after sensible heat recovery in boiler In the facility for controlling the amount of steam of the waste melting furnace facility comprising the device and the chimney that discharges the exhaust gas after treatment through the induction fan,
A filling level measuring device for measuring the filling level of the waste in the waste melting furnace installed in the waste melting furnace;
A generated steam amount measuring device for measuring a generated steam amount of a boiler installed in the boiler;
An induction fan operating load measuring device for measuring an operation load of the induction fan; and
An exhaust gas amount measuring device for measuring the exhaust gas amount at the exit of the chimney;
A flow rate for inputting the measurement results from each of the measuring devices, calculating the air flow rate to the tuyere based on the measurement value having the largest fluctuation value of these measurement results, and adjusting the air flow rate sent to the tuyere An apparatus for controlling the amount of steam in a waste melting furnace, comprising: an air supply control device that outputs a control signal for adjusting the opening of the valve to a control valve.

Images