JP2504345Y2 - Fluidized bed firing equipment for powdery granular materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a powdery granular raw material having an improved means for recharging the temperature-reduced trapped dust in the exhaust gas discharged from above the suspension preheater to the outside of the system. The present invention relates to a fluidized bed firing apparatus.

[Prior Art] A suspension preheater, which is configured by arranging a plurality of cyclones in multiple stages, is continuously provided above a fluidized bed firing furnace.
The exhaust gas of the fluidized bed firing furnace is introduced into the system of the suspension preheater, the powdery granular material circulating in the system is preheated, and the preheated powdery granular material is charged into the fluidized bed firing furnace to be fired. , A means for supplying and recovering to the fluidized bed cooler via the chute and a means for supplying and recovering the powdery granular material collected by the collecting cyclone to the fluidized bed cooler via the chute, while being collected from above the suspension preheater. The high-temperature exhaust gas discharged outside the system is heat-exchanged in the waste heat boiler to lower the temperature, and the dust in the low-temperature exhaust gas is collected by a dust collector such as a bag filter, and the exhaust gas is discharged outside the system. The fluidized bed calciner designed to release is "Mitsubishi Heavy Industries Technical Report" VOL.14 NO.5 issued in September 1977.
Is disclosed in.

[Problems to be Solved by the Invention] Although there is no disclosure in the above-mentioned document regarding a subsequent treatment means for low-temperature dust collected by a bag filter,
Generally, the following dust processing method is presumed.

(A) It is mixed in the product.

(B) Dispose as industrial waste.

(C) It is mixed in the granular material.

(D) Recharge to the fluidized bed firing furnace.

However, if dust is mixed in the product, the quality of the product such as firing rate, activity rate, whiteness, etc. will be deteriorated, and if it is disposed as industrial waste, this collected dust has no use as a by-product. In addition, the cost required for disposal is large, and the loss due to the reduction in product yield is enormous.
In addition, when disposing of the powdered and granular material, the collected dust is pulverized by the bag filter, and most of it scatters in the suspension preheater system, and the circulation with the bag filter is improved, and the When the waste is re-introduced into the layer firing furnace, the dust is burned, but the collection cyclone cannot be collected efficiently because it is at a high temperature.Therefore, the amount of dust circulation inside the suspension preheater increases, and the recarbonation reaction temperature increases. There is a problem that the fine powder adhesion growth in a cyclone of 600 to 800 ° C, which is the region, is fast and hinders the continuous operation of the fluidized bed firing apparatus for a long time.

An object of the present invention is to cool low-temperature dust collected by a bag filter into a product discharge chute that connects a fluidized bed firing furnace and a fluidized bed cooler and / or a product discharge chute that connects a collection cyclone and a fluidized bed cooler. Input and supply, heat exchange with high temperature products flowing down in the product discharge chute, for example, about 800 ° C to burn the dust, collect with a cooler cyclone with small temperature and high dust collection efficiency, and collect as products It is intended to provide a fluidized bed firing apparatus of powdery granular material having a good yield as described above.

[Means for Solving the Problems] The structure of the present invention for solving the problems of the prior art is such that a suspension preheater configured by arranging a plurality of cyclones in multiple stages is continuously provided above a fluidized bed firing furnace. The exhaust gas of the fluidized bed firing furnace is introduced into the system of the suspension preheater, the powdery granular material circulating in the system is preheated by heat exchange with the exhaust gas, and the preheated powdery granular material is charged into the fluidized bed firing furnace. The product obtained by firing is cooled through a product discharge chute having an L valve and a product discharge chute having a backflow prevention means such as a seal damper connected to a collection cyclone directly connected to the fluidized bed baking furnace. In a fluidized bed calcination device for powdered and granular raw material, which is designed to be supplied to and recovered from a fluidized bed cooler equipped with a cyclone, an exhaust gas system connected above the suspension preheater outside the system. The charging chute of the low temperature dust collected by the discharging treatment means is provided with a product discharging chute above the L valve, and / or
It is connected to the product discharge chute above the backflow prevention means.

[Operation] The exhaust gas whose temperature has been reduced by heat exchange in the waste heat boiler has dust collected in the exhaust gas by the bag filter,
The low-temperature exhaust gas is released outside the system. Then, the dust collected by the bag filter is put into a product discharge chute that connects the fluidized bed firing furnace and the fluidized bed cooler and / or a product discharge chute that connects the collection cyclone and the fluidized bed cooler, The heat is exchanged with a high temperature product of 800 ° C to burn the dust, and it is collected as a product in a cooler cyclone with a low temperature and small size and high dust collection efficiency.

[Embodiment] Next, the embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partially cutaway front view of the first embodiment, and FIG.
It is a partially cutaway front view of an example.

First, the first embodiment will be described with reference to FIG. 1. A plurality of cyclones C ₁ , C ₂ , C ₃ , and C ₄ are arranged in multiple stages to form a suspension preheater 1. The limestone or the granular material such as dolomite charged from the material charging chute 3 provided in the inlet side duct 2 of the uppermost cyclone C ₄ constituting the suspension preheater 1 is
Preheated by the exhaust gas from the fluidized bed firing furnace 4, the preheated powdery granular material is successively introduced into the fluidized bed firing furnace 4 and fired. The product fired in the fluidized bed firing furnace 4 is
It is guided to the fluidized bed cooler 9 through a product discharge chute 6 provided with an L valve 5 in the middle and a product discharge chute 8 having a seal damper 7 connected to the collection cyclone C ₀ directly connected to the fluidized bed firing furnace 4. , Where it is cooled and collected as a product from a conveyor (not shown).

On the other hand, the high-temperature exhaust gas discharged to the outside of the upper system of the suspension preheater 1 is lowered in temperature by the heat exchange action in the waste heat boiler 10, and the dust contained in this low-temperature exhaust gas is substantially removed by the bag filter 11. It is completely collected, and the exhaust gas is discharged outside the system as shown in the figure. The waste heat boiler 10, and dust collected by the bag filter 11, is collected in the screw conveyor 12,
A dust charging chute 13 provided at one end of the screw conveyor 12 is connected to the L charging chute 14 and 15 via the branch charging chute 14 and 15.
It is connected to a product discharge chute 6 above the valve 5 and a product discharge chute 8 above the seal damper 7. Then, the dust is mixed with the product of about 800 ° C. flowing down in the product discharge chute 6,8, and the dust is burned by the heat exchange effect and guided to the fluidized bed cooler 9 together with the product. Collected by the cooler cyclones 9a and 9b.

Referring to the second embodiment shown in FIG. 2, this embodiment is an improvement of the dust charging means in the above-described first embodiment, and the dust charging chute 13 connected to the screw conveyor 12 is used. Is connected to the duct bin 16, and a charging chute 19 having a flow rate adjusting valve 18 is attached to a screw conveyor 17 whose one end is connected to the lower end of the dust bin 16.
To the product discharge chute 6 above the L valve 5,
A charging chute 21 having a flow rate adjusting valve 20 is connected to the product discharging chute 8 above the seal damper 7. In addition, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, in the second embodiment, the temperature sensors T ₁ and T ₂ for the products are provided below both the product discharge chutes 6 and 8, respectively.
The flow rate adjusting valves 18 and 20 are controlled by the detection signals of T ₁ and T ₂ , and the product temperature below the product discharge chutes 6 and 8 is 800
The amount of dust is controlled so that the temperature is kept above ℃.

[Effect of the Invention] According to the configuration of the present invention as described above, the following effects can be obtained.

(A) The exhaust gas continuously provided above the suspension preheater is cooled to a low temperature in an external discharge treatment stage such as a waste heat boiler and a bag filter, and dust collected at a low temperature is discharged through a charging chute to a fluidized bed firing furnace. And the fluidized bed cooler are connected to the product discharge chute and / or the collection cyclone and the fluidized bed cooler are connected to the product discharge chute. In addition to firing, it can be collected with a cooler cyclone with small temperature and small size and high dust collection efficiency, and can be collected together with the product. In addition, since the sensible heat of the product to be cooled is used, it is not necessary to add the amount of heat for firing the dust.

(B) The temperature-reduced dust is supplied to the product discharge chute above the L valve and / or the product discharge chute above the backflow prevention means such as a seal damper, so that heat exchange with the high temperature product is performed. The efficiency can be improved, and the dust can be evenly baked.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of the first embodiment, and FIG. 2 is a partially cutaway front view of the second embodiment. C ₀ ... collection cyclone, C ₁ , C ₂ , C ₃ , C ₄ ... cyclone, 1 ... suspension preheater, 2 ... duct,
3 ... Raw material charging chute, 4 ... Fluidized bed firing furnace, 5 ...
L valve, 6 ... Product discharge chute, 7 ... Seal damper, 8 ... Product discharge chute, 9 ... Fluidized bed cooler, 9
a, 9b …… Cooler cyclone, 10 …… Waste heat boiler, 11 ……
Bag filter, 12 …… Screw conveyor, 13 …… Injection chute, 14,15 …… Branch chute, 16 …… Dust bin, 17 …… Screw conveyor, 18 …… Flow rate adjusting valve, 19
...... Charging chute, 20 …… Flow rate adjusting valve, 21 …… Charging chute, T ₁ , T ₂ …… Product temperature sensor.

Claims (1)

(57) [Scope of utility model registration request] 1. A suspension preheater comprising a plurality of cyclones arranged in multiple stages is continuously provided above the fluidized bed firing furnace, and exhaust gas from the fluidized bed firing furnace is introduced into the system of the suspension preheater. The powdery granular material circulating in the system is preheated by heat exchange with this exhaust gas, and the preheated powdery granular material is put into a fluidized bed firing furnace to be fired. The obtained product is a product discharge chute having an L valve, And, a granular material which is supplied and recovered to a fluidized bed cooler equipped with a cooler cyclone through a product discharge chute having a backflow prevention means such as a seal damper connected to a collection cyclone connected to a fluidized bed firing furnace. In the fluidized bed calcination apparatus of the above, the charging chute of the low temperature dust collected by the exhaust gas outside emission treatment means continuously provided above the suspension preheater is Product discharge chute above L valve,
And / or a fluidized bed calcination device for powdered and granular raw materials, which is connected to a product discharge chute portion above the backflow prevention means.