JPH037617B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a white cement manufacturing apparatus in which raw materials preheated by a suspension preheater are fired in a rotary kiln and then cooled by sprinkling with water in a cooling device.

Referring to FIG. 1, in the conventional white cement manufacturing apparatus, raw materials preheated by a suspension preheater 1 are fired in a rotary kiln 2, and then
White cement is manufactured by sprinkling water with a water spray nozzle 4 in a rotary cooler 3 serving as a cooling device. In such conventional white cement production equipment, the sensible heat of the clinker heated to high temperature after being fired in the rotary kiln 2 is not recovered, so the heat consumption is large, for example, per 1 kg of clinker.
It was around 1400Kcal. Therefore, the amount of exhaust gas from the rotary kiln increases, and accordingly, the suspension preheater 1 becomes larger than necessary, and the exhaust gas temperature at the outlet of the suspension preheater 1 becomes relatively high. Therefore, a cooling device 7 using water sprinkling to protect the induced fan 6 is provided in the middle of the exhaust duct 5 that leads the exhaust gas from the suspension preheater 1 to cool the exhaust gas. Furthermore, as the amount of exhaust gas increases, the amount of ducts, that is, the amount of raw materials removed from the suspension preheater 1 increases. As a result, the amount of raw materials input to the suspension preheater 1 increases, and accordingly, the equipment for the pre-process such as a crusher and transport equipment for crushing the raw materials becomes larger.
Power consumption was increasing.

The present invention solves the above-mentioned technical problems, and provides a white cement manufacturing apparatus that minimizes the amount of exhaust gas introduced into the suspension preheater, downsizes the suspension preheater, and reduces the amount of raw material input. The purpose is to provide.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system diagram of an embodiment of the present invention,
In FIG. 2, solid arrows indicate the flow of raw materials, and dashed arrows indicate the flow of gas. This white cement manufacturing apparatus includes a suspension preheater 10, a rotary kiln 11 connected to the suspension preheater 10 via a rising duct 20, and a rotary cooler 12 as a cooling device. In the suspension preheater 10, the raw material is introduced into the duct 14 as shown by the arrow 13, and then
It is blown up by high-temperature exhaust gas from below and exchanges heat.
It is collected by cyclone 15 and falls to the lower stage. Next, the raw material flows through duct 16 → cyclone 17 → duct 18 → cyclone 19 → rising duct 20 → cyclone 21, and is preheated to about 800 to 850°C. Raw materials from cyclone 21 are sent to chute 22
It is fed into the rotary kiln 11 via. In the rotary kiln 11, raw materials are converted into clinker by a burner 24, and this clinker is cooled by water sprinkling from a water nozzle 25 in a rotary cooler 12 serving as a cooling device, and then discharged as a product. On the other hand, the exhaust gas that has undergone heat exchange with the raw material in the suspension preheater 10 is discharged through an exhaust duct 27 provided with an induced blower 26 .

According to the present invention, one end of the air bleed duct 28 is connected to the middle of the rising duct 20, and the other end of the air bleed duct 28 is connected to the discharge duct 27 downstream of the induced blower 26. In the middle of the bleed duct 28, a cyclone 29 as a dust collector, a cooling device 30 using water spray, and an induced fan 31 are provided in order from the upstream side to the downstream side. The amount of exhaust gas extracted from the extraction duct 28 is set so that the amount of exhaust gas guided to the suspension preheater 10 out of the exhaust gas from the rotary kiln 11 is the minimum value necessary to preheat the raw material. The capacity of the induced blower 31 is selected.

In this way, the amount of exhaust gas guided from the rotary kiln 11 to the suspension preheater 10 becomes the minimum necessary, so the suspension preheater 10 is made smaller and the exhaust duct 27
The temperature of the exhaust gas discharged into the tank becomes relatively low. Therefore, a cooling device for protecting the induced blower 26 is not required. Also, suspension preheater 1
As the amount of exhaust gas led out from zero is reduced, the amount of raw material removed from the suspension preheater 10 is also reduced, so there is no need to input an unnecessarily large amount of raw material. Therefore, it is possible to downsize the crusher and transportation equipment in the previous process, and the power consumption is reduced.

Dust in the exhaust gas extracted from the rising duct 20 is removed in a cyclone 29. The collected dust is returned to the rotary kiln 11 via the chute 32. Therefore, the amount of dust carried away by the extracted exhaust gas is extremely small, and the increase in heat consumption due to the sensible heat of the dust being discharged is extremely small. In addition, induced blower 3
1, it is necessary to provide a cooling device 30, but since the amount of exhaust gas extracted is small, the cooling device 30 may be small.

FIG. 3 is a system diagram of another embodiment of the present invention,
Parts corresponding to the embodiment of FIG. 2 are given the same reference numerals. In the previous embodiment, the extracted exhaust gas was cooled by a cooling device 30 (see FIG. 2), but in this embodiment, heat is recovered by a heat exchanger 33. This heat exchanger 33 is provided upstream of the induced fan 31. As a result, the amount of heat retained in the extracted exhaust gas, which was wasted in the embodiment shown in FIG. 2, can be effectively recovered. Note that the heat exchanger 33 may be a boiler, and the steam obtained from this boiler may be used to preheat heavy oil used in the burner 24 of the rotary kiln 23.

FIG. 4 is a system diagram of another embodiment of the present invention,
Parts corresponding to the respective embodiments described above are given the same reference numerals. In this embodiment, a calcining furnace 34 is provided downstream of the connection position of the bleed duct 28 in the riser duct 20, that is, above. The heat exchanger 33 is an air preheater, and a part of the air preheated by the air preheater is supplied as combustion air to the burner 24 of the rotary kiln 11 via the pipe 36, and the remaining preheated air is The air is supplied as combustion air to the burner 38 of the calciner 34 via the pipe 3. In this way, the amount of heat retained in the extracted exhaust gas is recovered for preheating the combustion air.
Fuel consumption in burners 24, 38 is reduced.

Although the provision of the calcination furnace 34 has the effect of reducing the amount of NOx produced in the exhaust gas, the calcination furnace 34 may be omitted in other embodiments of the present invention.

As described above, according to the present invention, a part of the exhaust gas discharged from the rotary kiln is extracted and the remaining exhaust gas is guided to the suspension preheater, so that the suspension preheater can be downsized, and The amount of raw material input can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the prior art, FIG. 2 is a system diagram of one embodiment of the present invention, and FIGS. 3 and 4 are system diagrams showing other embodiments of the present invention. 10...Suspension preheater, 11...
Rotary kiln, 12...Rotary cooler, 20
...Rising duct, 27...Discharge duct, 28...
... Bleeding duct, 29 ... Cyclone, 33 ... Heat exchanger, 34 ... Calciner.

Claims (1)

[Scope of Claims] 1. In a white cement manufacturing apparatus in which raw materials preheated by a suspension preheater are fired in a rotary kiln and then cooled by sprinkling water in a cooling device, exhaust gas is discharged from the rotary kiln to the suspension preheater. An air bleed duct is connected in the middle of the rising duct to extract a part of the exhaust gas and guide it to the exhaust duct from the suspension preheater, and a bleed air duct is connected in the middle of the air bleed duct to remove dust from the extracted gas. A white cement manufacturing apparatus characterized in that it is equipped with a dust collector for returning the white cement to the rotary kiln. 2. The white cement manufacturing apparatus according to claim 1, wherein a heat exchanger is provided downstream of the dust collector in the air extraction duct. 3. The white cement manufacturing apparatus according to claim 2, wherein the heat exchanger is an air preheater, and includes a pipe line for guiding air preheated by the air preheater to a rotary kiln. 4. Claim 3, characterized in that a calciner is provided downstream of the connection position of the bleed air duct in the riser duct, and a conduit for guiding preheated air to the calciner is provided. white cement production equipment.