JP4720354B2 - Waste disposal method and apparatus - Google Patents

Description

The present invention relates to a waste processing method and apparatus for processing waste in a calcining furnace of a cement manufacturing apparatus.

In recent years, attempts have been made to stably treat waste in various technical fields. For example, Cited Document 1 describes a combustible dust blowing facility in which a double damper is directly connected to a conveyance path. However, since the double dampers arranged in the vertical direction are alternately opened and closed, the amount of combustible dust supplied to the blowing device pulsates.
JP 2004-85174 A

Also in the cement field, an attempt has been made to effectively use as a substitute for fuel and raw materials for cement production by processing waste in a cement production apparatus. When a large amount of waste having different shapes and sizes is to be supplied to the swirl chamber of the calciner through a chute having a double damper, if the waste supply amount pulsates, the temperature in the calciner It is assumed that the supply amount of coal as fuel and other operating conditions will fluctuate greatly. As a result, it is expected that the operating conditions of the calciner that require strict temperature control will become extremely complicated.

An object of the present invention is to provide a waste supply apparatus, a processing method, and a processing apparatus for stably supplying waste to a calcining furnace of a cement manufacturing apparatus and processing the waste in large quantities.

The present invention includes a waste receiving port, a waste retaining portion having a double damper provided at a lower portion of the receiving port, and a waste outlet provided at a lower portion of the retaining portion. In the article supply apparatus, the staying unit includes a plurality of rooms partitioned in a vertical direction, a double damper provided in each room, and a control unit for controlling the double damper. It is a supply device.
As another invention, the discharge port of the waste supply device is connected to the waste reception port provided in the vortex chamber for introducing the cooler bleed gas extracted from the clinker cooler into the calciner. It is a waste disposal device.

  According to the present invention, the pulsation of the amount of waste supplied to the calcining furnace is alleviated, the dispersion of waste is improved, and heat loss can be reduced. As a result, it becomes possible to stabilize the operating conditions of the cement manufacturing apparatus such as temperature, pressure, oxygen concentration, etc., and it becomes possible to treat a large amount of waste having different shapes and sizes. As a result, waste can be effectively used as an alternative to cement manufacturing fuels and raw materials, and the life of the waste disposal site can be extended.

Hereinafter, the content of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view of a waste supply apparatus for carrying out the present invention.
The waste supply device 31 includes a waste reception port, a waste retention unit having a double damper provided at a lower portion of the reception port, and a waste discharge port provided at a lower portion of the retention unit. Have. The supply device 31 has a cylindrical or square shape. The inner diameters of the waste receiving port 23 and the discharge port 12 may be the same as those of the staying portion 32, but can be appropriately changed depending on the size of the waste and the connected device.
The stay part 32 has a partition plate 30 in the vertical direction. The partition plate 30 has a role of distributing waste to each partitioned room. The length of the partition plate 30 is 60 to 100%, preferably 70 to 75%, with respect to the length of the straight body portion of the staying portion 32. Space can be saved by integrating the supply path.

In each partitioned room, dampers 24 to 27 are installed in the vertical direction. A slide gate type is mentioned as a damper. The angle of the damper is 0 to 75 degrees when the horizontal direction is 0 degrees. When the angle of the damper is large, it is possible to prevent the waste from being stuck in the upper part of the damper. However, since the supply path becomes long, the preferable angle is 20 to 45 degrees. As a result, it is possible to prevent the stagnation of the waste and at the same time to reduce the installation space of the supply path.

The distance between the dampers in the same room can be appropriately changed depending on the size and shape of the waste and the supply amount. For example, when the size of the waste is 50 mm in the longest diameter and the straight barrel portion of the staying portion 32 is 2000 mm, the distance from the upper portion of the straight barrel portion to the upper damper is 600 to 1200 mm, preferably 700 to 900 mm. The distance between them is 400 to 1000 mm, preferably 400 to 650 mm, and the distance from the lower damper to the lower part of the straight body is 500 to 1000 mm, preferably 600 to 800 mm. Further, the upper and lower positions of the upper (24 and 26) and lower (25 and 27) dampers of different rooms are the same. The double damper driving directions are opposed to each other in FIG. 1, but may be parallel depending on the installation space of the supply path.

As shown in FIG. 1, the dampers 24 to 27 are connected to the control unit 29. The control unit 29 has a role of opening and closing the dampers 24 to 27 according to the time schedule.

Next, the invention according to claim 2 will be described. FIG. 2 is a schematic view of a cement manufacturing apparatus for carrying out the present invention. The cement manufacturing apparatus includes a rotary kiln 1 for firing cement raw material, a suspension preheater including a calcining furnace 2 having a vortex chamber 5, a clinker cooler 3 (hereinafter referred to as AQC) for cooling a cement clinker with cooling air, and a cooler. A suspension preheater is connected to the raw material supply side of the rotary kiln 1 and an AQC is connected to the cement clinker discharge side. Further, the AQC and the vortex chamber 5 are connected by a cooler bleed gas duct 6 so that hot air discharged from the AQC is introduced into the calcining furnace 2 as secondary air.
3 and 4 are a plan view and a side view of the calcining furnace 2 having the vortex chamber 5 for carrying out the present invention, respectively.
The vortex chamber 5 has the waste receiving port 34 and is connected to the discharge port 12 of the waste supply device. The supply port 34 is located at a ceiling part of the vortex chamber 5, preferably 0 to 3 m from the center radius of the ceiling part, and 1 to 4 m away from the connection part with the cooler bleed duct 6.
Further, the supply device 31 is 0 to 20 degrees, preferably 0 degrees, when the vertical angle with respect to the ceiling portion of the vortex chamber 5 is 0 degrees. Thereby, it becomes possible to supply waste stably by gravity, and the blockage problem of the supply part accompanying supply of waste is solved. In addition, while ensuring a long residence time of the waste, the waste can be reliably burned by a high oxygen atmosphere near the outer periphery.

A gas supply nozzle (A) 22 for supplying gas is installed at the waste receiving port 34 of the vortex chamber 5. The gas supply nozzle 22 has an injection nozzle mechanism bent in an L-shaped elbow shape from the ceiling of the vortex chamber 5. The tip of the supply nozzle (A) 22 reaches the upstream side of the waste receiving port 34. The horizontal distance L1 between the tip of the supply nozzle (A) 22 and the open end of the receiving port 34 is 100 to 1000 mm as shown in FIG. 5, and the vertical distance L2 is 500 to 1500 mm. The shape of the tip of the injection nozzle is usually round, but may be any of square, ellipse, oval, rectangle, half moon, harmonica, porous, and the like. As a result, the waste supplied to the vortex chamber 5 is immediately well dispersed in the vortex chamber, and can be prevented from falling to the cooler bleed gas duct 6 or the bottom of the vortex chamber 5 to be deposited and fixed.

As shown in FIG. 6, a gas supply nozzle (B) 33 different from the gas supply nozzle (A) 22 is provided in the vortex chamber 5 into which the waste is introduced. As a result, even when waste having a large inertia force of 100 mm or more in the longest part is supplied to the vortex chamber 5, combustion treatment can be performed without depositing and fusing to the lower portion of the vortex chamber 5. A more stable operation is achieved. The gas supply nozzle (B) 33 is not particularly limited as long as the waste can be blown up. For example, from the side of the vortex chamber 5 to the bottom of the vortex chamber 5 descending from the waste inlet 34 in the vertical direction. Then, it is oriented in the direction of 20 to 75 degrees obliquely downward from the horizontal. The gas can be introduced from two or more locations. For example, gas supply nozzles (B) 33 can be provided at two locations, the inner peripheral portion near the core at the bottom of the vortex chamber 5 and the outer peripheral portion near the furnace wall at the bottom of the vortex chamber 5.

  The waste used in the present invention is a single item or a mixture of two or more types of combustible wastes such as waste plastic, waste wood, wood chips, old tatami mats, waste paper, waste rubber, cloth cracks, and solid fuel (RDFs). Say. When foreign matter such as iron scraps or aluminum pieces is mixed in the waste, it is removed in advance by means such as a magnetic separator, a non-ferrous material removing device, and a sieve. The maximum length of the waste is 100 mm or less, preferably 70 mm or less. When the longest part is 100 mm or more, the inertial force is large even if the swirl flow in the vortex chamber 5 is taken. Since it falls to the kiln bottom part 21 via the rising duct 9 and adheres to the furnace wall, it is not preferable. Waste having a maximum length of 30 mm or less immediately rises upward due to the kiln exhaust gas 13 from the rising duct 9 at the lower part of the calcining furnace 2, so that the residence time in the high oxygen region is short and is supplied from the coal burner 8. Shows the same combustion behavior as pulverized coal. The ratio of the waste to the pulverized coal supplied from the coal burner 8 is 10 to 40% by weight.

The waste is stored in each room partitioned by the partition plate 30 via the receiving port 23. The double damper in each room is controlled so that the opening and closing timing is different.

FIG. 7 shows an operation driving time schedule of the double damper for carrying out the present invention. For the sake of convenience, the room on one side of the partitioned room is set as system 1 and the other is set as system 2.
First, the upper stages 24 and 26 and the lower stages 25 and 27 of the first and second systems are closed.
Next, wastes are filled on the upper stages 24 and 26 of the first and second systems from the inlet 23. Next, the upper stage 24 of the first system is opened, and the lower stage 27 of the second system is opened at the same time. As a result, in the first system, the waste is received between the upper and lower stages, and in the second system, the waste is supplied to the processing apparatus.
Thereafter, the upper stage 24 of the first system is closed, and at the same time the lower stage 27 of the second system is closed. As a result, the upper and lower dampers of the 1st and 2nd systems are all closed.
Next, the lower stage 25 of the first system is opened, and the upper stage 24 of the second system is opened. As a result, the waste is supplied from the first system to the processing apparatus, and the waste is received between the dampers 26 and 27 in the second system.
Thereafter, the lower stage 25 of the first system is closed, and at the same time, the upper stage 27 of the second system is closed. As a result, the upper and lower dampers of the 1st and 2nd systems are all closed. This completes the waste supply cycle.
By repeating this cycle, the waste is supplied to the processing apparatus. As a result, the pulsation of the amount of waste supplied to the processing apparatus can be alleviated, and fluctuations in operating conditions of the processing apparatus can be greatly reduced.

Each time width of the time schedule is set by an electronic timer or soft timer according to the required amount of waste supply, but the open time range of the upper damper is between the lower damper and the upper damper. The time width of the timer is set so that the chute space is not filled with waste, that is, 80% or less of the full amount. In addition, with respect to the above, a level switch or a limit switch 28 is attached at a position where the height is 80% of the full amount, and is used in combination with the timer. When the level detection or timer operation is performed, the damper is set to a predetermined level. The waste may be operated in a stable manner so that the waste can be supplied stably. If the width of the timer time is too large, waste may get caught in the tip of the double damper.

In the above description, the two-line waste supply apparatus has been described. However, the present invention can be implemented in three or more lines. The double damper driving method in this case is the same as the time schedule of each series described above, and only provides a time difference. Thereby, it is possible to further reduce the pulsation of the waste supply amount. However, as the number of series increases, the structure of the supply path becomes complicated and the control of the drive of the damper becomes complicated. Therefore, the number of series is preferably 2 to 4 series.

The waste whose supply amount pulsation is reduced by the control of the double damper is supplied to the vortex chamber 5 for introducing the cooler bleed gas 11 extracted from the clinker cooler into the calciner 2. The waste supplied to the vortex chamber 5 is combusted while slowly swirling on the swirling gas 15 around the circumferential portion 10 of the calciner vortex chamber 5 that has become an atmosphere of high temperature and high oxygen by the cooler bleed gas 11. Accelerated. Thereby, the residence time of a waste can be ensured longer than before by carrying out swirling behavior in the combustion space in a furnace with high oxygen concentration.
Thereafter, the waste having a relatively large inertial force circulates around the inner wall portion of the calciner 2 as a flying trajectory 16 by a centrifugal force in the calciner upper chamber 17 by centrifugal force. Burn while. The gas generated by the combustion of the waste naturally merges with the jet gas 14 that penetrates the central longitudinal axis of the calciner upper chamber 17 from the bottom to the top. Thereby, the combustion treatment can be performed without the waste being fused to the furnace wall.

A kiln exhaust gas 13 having a gas temperature from the rotary kiln 1 of 1000 to 1200 ° C. and an oxygen concentration of 1 to 3% by volume extends from the bottom to the center of the calciner 2 along the central axis of the calciner 2. The jet gas 14 penetrates at high speed. Therefore, in the calciner 2, the vicinity of the center along the central axis is a low oxygen concentration region. On the other hand, the cooler bleed gas 11 having an oxygen concentration of 21% by volume from 850 to 900 ° C. from AQC is introduced into the vortex chamber 5 horizontally from the lateral direction of the calciner 2 through the cooler bleed gas duct 6. After slowly swirling the circumferential portion 10 as the swirling flow gas 15, the inside of the calcining furnace upper chamber 17 rises from the bottom to the top while forming a swirling flow in the horizontal upward direction along the periphery of the inner wall of the furnace. Therefore, the peripheral part near the furnace wall of the calciner 2 is a high oxygen concentration region.
On the other hand, the pulverized coal supplied from the coal burner 8 has a role of reducing atmosphere to reduce NOx in the preheater exhaust gas 19. That is, both pulverized coal and primary air are injected from the coal burner 8 in the flow direction of the jet gas 14 which is the kiln exhaust gas 13 having a low oxygen concentration from the rising duct 9. As a result, CO gas is generated by thermal decomposition at a high temperature of about 900 ° C. in the vicinity of the central vertical axis of the calciner upper chamber 17, and NOx in the preheater exhaust gas 19 is reduced by the CO gas.

Waste consisting of a mixture of polyethylene, polypropylene, nylon, waste wood, fiber waste, etc. was supplied to the supply device 31 and supplied to the vortex chamber 5 while controlling the double damper according to the time schedule. As a result, the gas temperature at the exit of the calcining furnace was 900 ° C. plus / minus 10 ° C. when waste was supplied to the vortex chamber 5 without using the supply device 31, whereas it was 900 ° C. plus / minus. The temperature fluctuation was reduced to half by 5 ° C. The amount of pulverized coal supplied to the calcining furnace 2 was 12.5 plus / minus 2 t / hr, but 12.5 plus / minus 1 t / hr. Furthermore, the fluctuation | variation of the CO gas concentration in the exit gas of the calciner 2 was not recognized. This indicates that the waste is stably burned in the calcining furnace 2 without causing a burning delay. As a result, the utilization rate of the amount of heat brought in from the waste could be greatly improved from about 70% to about 90%. Moreover, the stable treatment of the waste in the calcining furnace 2 enabled the stable operation of the rotary kiln 1, and the production amount of the clinker could be increased by 0.4% by weight.

Gas can be supplied to the inlet 34 to which waste is supplied. The gas is injected from the downstream side close to the supply port in parallel with the cooler bleed gas. Examples of the gas include compressed air, blower air, and exhaust gas discharged from a cement manufacturing apparatus. The tip flow velocity of the gas supply nozzle (A) 22 is 30 to 80 m / sec, preferably 40 to 60 m / sec. The gas supply amount is 0.1 to 5.0% by volume, preferably 0.5 to 3.0% by volume, with respect to the cooler bleed gas 11.

As the gas to be blown, a preheated gas can be used. For example, air heated by a shell-and-tube heat exchanger, or a pipe that is laid in a circular or snake-like shape on the outer wall of the calcining furnace 2 and heated by circulating air through the pipe is used. Can do. Thereby, the heat loss in the vortex chamber 5 can be prevented, and the operating conditions of the calciner can be further stabilized.

A gas can be supplied to the vortex chamber 5 separately from the gas supply nozzle (A). Examples of the gas include compressed air, blower air, and exhaust gas discharged from a cement manufacturing apparatus. The tip flow velocity of the gas supply nozzle (B) 33 is 30 to 80 m / sec, preferably 40 to 60 m / sec. The gas supply amount is 0.1 to 5.0% by volume, preferably 0.5 to 3.0% by volume, with respect to the cooler bleed gas 11. Also in this case, a preheated one as described above can be used.

The present invention can be used when a large amount of waste is used as a raw material or fuel for cement production.

It is the schematic of the waste supply apparatus for implementing this invention. It is the schematic of the cement manufacturing apparatus for implementing this invention. It is a top view of the calcining furnace for implementing this invention. It is a side view of the calcining furnace for implementing this invention. It is an enlarged view of the waste supply apparatus and gas supply nozzle for implementing this invention. It is another side view of the calcining furnace for implementing this invention. It is a time schedule which shows the drive method of the double damper for implementing this invention.

Explanation of symbols

1 Rotary kiln 2 Calciner 3 Clinker cooler 4 Kiln coal burner (pulverized coal)
5 Calciner vortex chamber 6 Cooler extraction gas duct 7 Exhaust fan 8 Coal burner 9 Rising duct (RD)
10 Outer and inner walls of vortex chamber 11 Cooler bleed gas (secondary air for calcining furnace)
12 Waste outlet 13 Kiln exhaust gas 14 Jet gas 15 Swirl gas 16 Waste trajectory 17 Calciner upper chamber 18 Cement raw material input port 19 Preheater exhaust gas 20 Preheater cyclone 21 Kiln bottom 22 Supply nozzle (A)
23 Waste Receiving Port 24 1st System Upper Damper 25 1st System Lower Damper 26 2nd System Upper Damper 27 2nd System Lower Damper 28 Level Switch or Limit Switch 29 Control Unit 30 Partition Plate 31 Supply Device 32 Retention Unit 33 Gas Supply Nozzle ( B)
34 Waste entrance

Claims (6)

Waste supply device having a waste receiving port, a waste retaining portion having a double damper provided at a lower portion of the receiving port, and a waste outlet provided at a lower portion of the retaining portion In the above, the stay part is a plurality of rooms partitioned in the vertical direction, a double damper provided in each room, a control part for controlling the double damper ,
A vortex chamber for introducing cooler bleed gas extracted from the clinker cooler into the calciner,
A supply nozzle (A) provided in the vortex chamber for supplying gas toward the waste receiving port;
With
The gas supplied from the supply nozzle (A) into the vortex chamber has a horizontal component.
Waste treatment equipment characterized by Processing apparatus according to claim 1 and a discharge port of the supply device of the waste described, waste receiving opening is connected waste provided in the swirl chamber. The waste processing apparatus according to claim 1 or 2, wherein a gas supply nozzle (B) different from the supply nozzle (A) for supplying the gas is provided in the vortex chamber. The waste treatment apparatus according to claim 3, wherein the gas supply nozzle (B) is inclined 30 to 80 degrees downward from a horizontal direction of the vortex chamber. The waste is received from the waste receiving port, the double damper provided at the lower portion of the receiving port is controlled, and the waste discharge port provided at the lower portion of the double damper is transferred to the waste processing apparatus. In the waste processing method for supply, the waste received from the receiving port is stored in a plurality of rooms partitioned in the vertical direction, and the opening and closing timings of the double dampers provided in the respective rooms are different. supplying the waste while controlling the,
A vortex chamber for introducing cooler bleed gas extracted from the clinker cooler into the calciner,
A supply nozzle (A) provided in the vortex chamber for supplying gas toward the waste receiving port;
With
The gas supplied from the supply nozzle (A) into the vortex chamber has a horizontal component,
The gas supply position is a position where the waste is supplied in the vortex chamber.
A method for treating waste. The waste gas treatment method according to claim 5 , wherein the gas is a hot gas heat-exchanged with an outer wall of the calciner.

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