JPS61101237A - Apparatus for heating fine particles by gas - Google Patents

Abstract

PURPOSE:To improve the separation of gas and duct, by providing a horizontal fluidized bed type heat exchange apparatus for contacting coarse particles heated by a tower type solid-gas heat exchange apparatus with separate fine particles countercurrently and a transport line for recirculating coarse particles between both apparatuses. CONSTITUTION:Coase particles are contained with the gas rising from the lower part of a tower type solid-gas heat exchange apparatus 120 and fallen while receives heat exchange to be supplied to a horizontal fluidized bed type heat exchange apparatus 101 through a coarse particle discharge port 117, a chute 112 and a coarse particle supply pipe 104. A coarse particle bed 111 is formed above the dispersing plate 102 in the horizontal heat exchange apparatus 10 and moved toward an outlet side while fluidized and crosses over a weir B to be discharged to a coarse particle discharge port 107. Then, said coarse particles pass through an air screening pipe 8, a rotary valve 109 and a recirculation line 113 to be returned to the top part 119 of the tower type solid-gas heat exchange apparatus 120.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a gas-based particle heating device.

(Prior art) As a known prior art, for example, in a cement, alumina, etc. calcination plant, as shown in Fig. 3, a cyclone 4
．． 5.6.7 stacked in multiple stages, suspension brake heater, calciner 2, rotary kiln 1, cooler 3
It is mainly composed of That is, 1 is a kiln, and coal (or heavy oil) is supplied from the right end, mixes with high-temperature air sent from a cooler 5, and burns it. High-temperature gas generated by combustion flows from the left end of rotary kiln 1 to cyclone 4.
5.6.7, and is guided out of the system by the fan 9.

On the other hand, the powdered cement raw material is supplied from the raw material chute 8, dispersed in the high-temperature gas rising from below, and is carried by the gas while exchanging heat with the gas, and enters the uppermost cyclone 7. Gas and raw materials are separated in cyclone 7,
The gas is guided out of the system from the upper part of the cyclone 7 by the tube 9, the raw material descends, and the same behavior as from the raw material supply chute 8 to the cyclone 7 described above is repeated, and the raw material is transferred to the cyclone 6.
5 and sent to the calcining furnace 2. In the similar kiln 2, air extracted from the cooler 3, supplied coal (or heavy oil), and air blown from the bottom by a fan are mixed, and the coal (or heavy oil) is combusted. By this combustion, the raw material coming in from the cyclone 5 is calcined, and is sent to the cyclone 4 along with the exhaust gas from the calciner 2. Cyclone 4
As a result, the gas and the calcined raw material are separated and the gas enters the upper cyclone 5 and repeats the behavior described above, while the raw material is discharged from the lower part of the cyclone 4 and fed to the left end of the rotary kiln 1. The supplied calcined raw material moves to the right side while flowing due to the rotation of rotary kiln 1.
It comes into countercurrent contact with a high-temperature flame or gas, is heated and fired, becomes clinker, and is discharged to the cooler 3. The clinker is cooled by cooling air blown up from the lower part of the cooler 3 by a prower, and is guided from the right end of the cooler 3 to a final crushing step (not shown). Furthermore, an exhaust duct is installed from the rear of cooler 3.
The exhaust gas passes through the dust collector 10 and is discharged into the atmosphere by the induced draft fan 11.

The above is the configuration of a conventional suspension preheater firing plant with a firing furnace.

Although this type of conventional equipment is currently widely used worldwide and is highly regarded as a useful device, it still suffers from high fuel consumption, power consumption,
Further reductions in construction costs are required. Although it is hard to say that there is no possibility of reduction in each, a reduction in any one will lead to an increase in one or two of the others, and we are approaching the limit for overall beneficial improvements.

(Problems to be Solved by the Invention) The reason why there is almost no room for improvement in conventional devices is that fine powder is handled by a suspension preheater. In other words, the components of the suspension brake heater can be said to be a cyclone and a gas duct. The part where heat exchange is mainly performed is the gas duct), and the cyclone is an essential separation device that separates the gas and fine powder, sending the former to the upper gas duct and cyclone, and the latter to the lower gas duct. . This low separation efficiency means that part of the fine powder, which has heated up through heat exchange with the gas, must be returned to the upstream gas duct or cyclone.
When the thermal efficiency is reduced, it becomes K. If the cyclone used as the separation device could be made smaller and the pressure loss could be reduced, this requirement could be met, but since fine powder is used as the raw material for cement, it is difficult to achieve further overall benefits.

For this reason, it is effective to meet the above requirements by using coarse particles instead of fine powder as a heating medium to exchange heat with rotary kiln or calciner exhaust gas, and by bringing the resulting high-temperature coarse particles into contact with the fine powder. I discovered that.

By doing so, the problem of separation in the heat exchange device for coarse particles and gas has been largely resolved, and furthermore, a cyclone with large pressure loss has become unnecessary.

Furthermore, it has been found that the coarse particle/fine particle heat exchange device proposed in the application filed on the same date as the present application can be applied to coarse particles and fine powder.

(Means for Solving the Problems) Based on the above knowledge, the present invention is comprised of the following device.

1) An upright type heat exchange device in which coarse particles and gas contact each other in a countercurrent flow. 2) A horizontal type in which coarse particles and fine powder form a lower layer and an upper layer, and contact each other while flowing in opposite directions to exchange heat. Fluidized bed heat exchange device 3) A coarse particle circulation device is provided between 1) and 2) above.

That is, the present invention provides a formal solid-air heat exchange device that brings coarse particles into countercurrent contact with a gas, and a horizontal fluidized bed type coarse particle/fine particle heat exchange device that brings coarse particles heated in the same device into countercurrent contact with other fine particles. This device is characterized by comprising a device and a transport line that circulates coarse particles between both devices.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

(1) Formal solid-gas heat exchange device The top portion 119 of the formal solid-gas heat exchange device 120, in which portions with a wide cross-sectional area and narrow portions (throat) overlap alternately, serves as a gas outlet and a coarse particle supply. The bottom part 121 is provided with a gas supply port 118 on the side surface and a coarse particle collection discharge port 117 at the lower end thereof.

Tower-type solid-gas heat exchanger 120 top 119 is Suicron 12
2 is connected to the fan 123 with a diameter.

Further, gas to the tower isotropic heat exchange device 120 is piped so as to be supplied from a rotary kiln 126 and a calcination furnace 124 to a cyclone 125 .

(2) Horizontal fluidized bed heat exchange device with coarse particles and fine particles Horizontal fluidized bed casing 101, dispersion plate or multiple nozzles (reciprocating operation grade is also possible) 102, blower 103,
Coarse particle supply pipe 104, partition plate (wall) or aperture 105
．． 105', fine particle discharge port 106, air sieve tube 108, coarse particle discharge port 107, rotary valve 109, fine particle layer 11
G, consists of a coarse particle layer 111, a fine particle supply pipe 114, and a fluidized air discharge pipe 115.

As shown in FIG. 2, which is a sectional view of the fluidized bed casing 101 taken along line XX in FIG. desirable.

On the particulate discharge port 106 side of the fluidized bed casing 101, a wall or weir is provided so that the height of the particulate layer 110 is kept constant and overflow occurs therefrom. Further, on the coarse particle outlet 107 side, a wall or weir of a constant height is provided so that the height of the coarse particle layer 111 can be kept constant and the coarse particles can be washed out from there.

As the dispersion plate or the nozzle 101, a known one can be used, and a description thereof will be omitted.

The partition plate (wall) or the aperture 105.10 da is provided as an example as shown in the figure, but it is intended to suppress mixing in the movement direction (lateral direction) of particles, and is not limited to this. do not have.

A wind sieve pipe 108 is provided below the coarse particle outlet 107.
Coarse particles and fine particles are separated, and only the coarse particles are extracted downward.

(3) A transport line 113o for returning other coarse particles from the horizontal fluidized bed heat exchanger 101 to the top of the base or solid-gas heat exchanger 120
' A line 129 that returns the fine particles collected by the cyclone 122 to the horizontal fluidized bed heat exchanger 101, a cyclone 116 for collecting fine particles in the exhaust from the horizontal fluidized bed heat exchanger 101, and a column type solid gas heat exchanger for the solid cyclone exhaust gas. A line 128 also leads to the upper part of the device 120, and a line 128 leads the collected powder to the horizontal fluidized bed heat exchange device 10.
1, a chute 129 leading to the bottom part 12 of the solid-gas heat exchanger
1. A chute 112° is provided for guiding the coarse particles from the coarse particle collection outlet 117 to the horizontal fluidized bed heat exchanger 101.

(Function) (1) Rotary kiln 126 exhaust gas, calcining furnace 124
Flow of Exhaust Gas Exhaust gas from the rotary kiln 126 and the calciner 124 passes through a cyclone 125 and is then transferred to a column-type solid-gas heat exchanger 120.
Enter through the gas supply port 118 at the bottom 121 of the device 12.
0, exchanges countercurrent heat with the coarse particles, and is discharged from the top 119. This gas is induced by a fan 123, and the dust is collected by a cyclone 122.

(2) Flow of coarse particles (heating medium) The coarse particles (heating medium) come into contact with the gas rising from the bottom to the top of the column-type solid-gas heat exchanger 120, and fall while exchanging heat. , chute 112, and coarse grain supply pipe 104, and are supplied to the horizontal fluidized bed heat exchanger 101.

In the horizontal fluidized bed heat exchanger 101, on the distribution plate 102,
A coarse particle layer 111 is formed at the bottom.1. While being fluidized,
It moves toward the exit side, crosses the weir (■), is discharged to the coarse particle discharge port 107, and is passed through the wind sieve tube 108 and the rotor pulp 109.
, through the circulation line 113 to the column-type solid-gas heat exchanger 120
is returned to the top 119 of. During this time, it contacts the fine particle layer 110 that is formed above the coarse particle layer 111 and moves in the opposite direction to the coarse particle layer 111, and is cooled. This coarse particle layer 11
1 and the fine particle layer 110 is the air jetted out from the dispersion plate 102 at the bottom of the horizontal fluidized bed heat exchanger 101. Since the horizontal fluidized bed heat exchanger 101 has a cross section as shown in FIG. 3, the coarse particles rise directly above the dispersion plate 102 and jump into the fine particle layer 110, but the gas flow rate decreases. This shows a convection phenomenon in which it stalls, splits into both sides, and descends near the wall. This is coarse particle layer 1
11 and the fine particle layer 110 to promote contact and heat exchange.

(3) Flow of Fine Particles Fine particles are supplied through the supply pipe 114 to the opposite side of the horizontal fluidized bed heat exchanger 101 from the coarse particle supply side. Since coarse particles have greater resistance to the upward gas flow than fine particles, the coarse particles sink downward and the fine particles float above, forming two layers, a coarse particle layer 111 and a fine particle layer 110, respectively. The height of each layer is determined by ■ of the weir.

The fine particles that have moved to the opposite side are heated by the coarse particles, cross over the weir, and are sent to the calciner 124 through the fine particle outlet 106. In the calcining furnace 124, fuel and air are supplied, the fuel is combusted, and the raw material is calcined by the heat. The raw material is entrained in the gas, further combined with the exhaust gas from the rotary kiln 126, and guided to the S/F clone 125.

Solid-gas separation is performed at and \, and the fine particles are supplied to a rotary kiln 126.

(4) In addition, the air supplied by the lower blower 103 of the horizontal fluidized bed heat exchanger 101 is divided into the coarse particle layer 111 and the fine particle layer 1.
After fluidizing 10, the diameter of the fluidized air discharge pipe 115 is,
The dust enters the cyclone 116, separates the dust, and sends it to the upper part of the column-type solid heat exchanger 120.

(Effects) (1) To bring the coarse particles into countercurrent contact with the rotary kiln 126 and calciner 124 exhaust gas and exchange heat with high thermal efficiency,
A simple, low-pressure-loss column-type solid-gas heat exchanger 120 is adopted, and (2) a horizontal fluidized bed type is adopted, which is simple and consumes less power to efficiently impart heat obtained from coarse particles to fine particles. Heat exchange device 1
Compared to the conventional suspension preheater, adopting 01 has higher thermal efficiency, increases the temperature of fine powder, and lowers the exhaust gas temperature, resulting in a reduction in overall fuel consumption.

(2) The number of cyclone stages used is reduced, the pressure loss in the column-type solid-gas heat exchanger 120 line is reduced, and the power of the horizontal fluidized bed heat exchanger 101 line is also small, resulting in a reduction in power consumption as a whole.

@ Overall, the entire device is smaller and the frame is simpler, reducing construction costs.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line X--X of FIG. 1, and FIG. 3 is an explanatory diagram of a conventional heating method.

Claims (1)

[Claims] A column-type solid-gas heat exchange device that brings coarse particles into countercurrent contact with gas, a horizontal fluidized bed type coarse particle/fine particle heat exchange device that brings coarse particles heated in the same device into countercurrent contact with other fine particles, and A device for heating fine particles using gas, characterized by comprising a transport line that circulates particles between both devices.