JPH01179745A - Cooler for cement clinker - Google Patents

Abstract

PURPOSE:To increase the efficiency of an electrostatic precipitator and to reinforce the cooling capacity by adding a part of the high-temp. air discharged to the atmosphere after dust removal to cooling air, and cooling cement clinker with sprayed water. CONSTITUTION:The cement clinker 6 discharged into a cooler 1 from a rotary kiln 2 is cooled by the cooling air from a cooling fan 10. A part of the high- temp. air generated by heat exchange is taken out from a high-temp. air outlet 20, and recovered as the heat source for heat utilizing device such as raw material crushing facilitates and exhaust power generating facilities. The residual high-temp. air is discharged from an exhaust port 5, removed from dust by an electrostatic precipitator, and then discharged into the atmosphere. A part of the air is taken out into a duct 21, introduced into cooling fans 22, 23, and 24, and added to the cooling air. Consequently, the surplus gas passing through the precipitator 11 is held at an appropriate temp., and an increase in the electrical resistivity can be controlled. In addition, a decrease in the cooling efficiency of the clinker 6 is offset by the sprayed water from a water spraying device 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cement clinker cooling device for cooling high-temperature cement clinker discharged from a kiln used subsequent to a cement kiln.

[Conventional technology]

Fig. 3 is a diagram showing the configuration of a conventional cement clinker cooling system, in which 1 is a cooler, 2 is a rotary kiln, 3 is a kiln foot 9 for connecting to the rotary kiln, and a secondary air outlet to the rotary kiln 2. .

4 is a secondary air intake port to the calcining furnace, 5 is an exhaust port for exhaust air,
6 is clinker, 7 is grate, 8 is clinker outlet, 9
10 is a cooling air chamber, 10 is a cooling fan for blowing cooling air,
11 is a dust collector for exhaust dust, 12 is an exhaust fan, and 13 is a transporter for the clinker 6 discharged from the cooling device after cooling.

Clinker 6 fired in rotary kiln 2 has a temperature of 130
When the temperature reaches 0 to 1400℃, it is introduced into cooler 1 and then heated to grade 7.
The clinker is deposited on top, moves to the clinker discharge port 8 along with the swinging movement of the grate 7, is discharged from the cooler 1, and is transported by the transporter 13 to subsequent equipment (not shown). While the clinker 6 moves on the grate 7, it exchanges heat with the cooling air blown into the cooling air chamber 9 below the grate 7 by the cooling fan 10, and is cooled. Clinker 6
The high-temperature air that exchanges heat with the rotary kiln 2 is recovered as secondary air for combustion in the rotary kiln 2 and the calciner at the kiln hood 3 of the rotary kiln 2 and the secondary air outlet 4 to the calciner. The unrecovered air is exhausted from the exhaust port 5 by the exhaust fan 12. As described above, in the conventional cooling system, in order to cool the high-temperature clinker 6 flowing into the cooler 1 to a predetermined temperature (usually around 100 degrees Celsius), the amount of cooling air is usually 2.3 to 2.5 per 1 kg of clinker. Nm
3A9cli is required. On the other hand, the amount of secondary air recovered to the rotary kiln 2 and calciner is 08 to 1 ONm3//i
Kgc11 (its temperature is about 900°C on average). Therefore, the surplus air is 1.3 to 1.7 Nm3/kgc.
11 is discharged from the cooling device, and after dust removal by the dust collector 11, it is discharged into the atmosphere. Normally, the temperature of the released excess air is 2
The temperature is 30-250°C. The surplus air from the cooling system generally contains clinker dust of 10 to 30 g/N to 3, and multi-cyclone or electrostatic precipitator is generally not used as the dust collector 11, but in recent years regulations to prevent air pollution have been introduced. Electrostatic precipitators are mainly used to meet the requirements.

When using an electrostatic precipitator, there are restrictions on the gas temperature at the inlet of the precipitator. Figure 2 is a diagram showing the relationship between the temperature and electrical resistivity of clinker dust.As shown in the figure, the electrical resistivity of clinker dust generally changes depending on the temperature, and is 10"Q
If the resistivity is greater than -ex, it becomes difficult to collect dust with an electrostatic precipitator. Therefore, the specific resistance of clinker dust is 10
In order to keep it below ″Ω−α, the temperature of the dust collector inlet gas should be set to 2.
It is necessary to keep the temperature above 00°C or below 100°C.

[Problem to be solved by the invention]

The conventional cement clinker cooling device described above had the following problems to be solved. In other words, coal is used as fuel in the kilns and calciners of cement firing equipment, but coal contains moisture, and in order to dry and crush it, a portion of the high-temperature air generated in the cooling device described above must be recovered. It is often used. Furthermore, as a heat source for drying and pulverizing cement raw materials, the exhaust gas from a floating heat exchanger for preheating raw materials with the combustion gas generated in the kiln or calciner of cement firing equipment is usually used. However, if the raw material contains a large amount of water, the exhaust gas from the floating heat exchanger alone is insufficient, and a portion of the high-temperature air generated by the cooling device is recovered and used. In this way, the cooling system not only recovers the secondary air for combustion in kilns and calciners, but also collects it in other heat utilization equipment (drying and crushing equipment for raw materials and coal), from the cooling system to the atmosphere. The amount of excess air released will be smaller and the temperature will be much lower. The normal temperature will be 160-180°C. Therefore, as shown in FIG. 2, the electrical resistivity of the clinker dust contained in the surplus air released into the atmosphere becomes 10''Ω-α or more, reducing the collection efficiency of the electrostatic precipitator.

[Failure to solve the problem]

As a solution to the above problems, the present invention cools high-temperature cement clinker discharged from a cement kiln with cooling air, and uses a part of the high-temperature air generated by heat exchange with the cement clinker as a heat source for heat utilization equipment. In a cooling device for cement clinker, which recovers the remaining high-temperature air and discharges it to the atmosphere after dust removal using an electrostatic precipitator, a means for extracting a part of the high-temperature air released to the atmosphere after dust removal and adding it to the cooling air;
It is an object of the present invention to provide a cooling device for cement clinker characterized by comprising a water spray means for water-cooling the cement clinker that is cooled by the cooling air and discharged.

[For production]

Since the present invention is configured as described above, it has the following effects.

(1) Since a portion of the high temperature air released into the atmosphere is added to the cooling air, the temperature of the exhaust gas passing through the electrostatic precipitator increases, suppressing the specific resistance of dust and maintaining high dust collection efficiency.

(2) The cooling capacity of the cement clinker, which is reduced by adding hot air to the cooling air, is compensated for by spraying water onto the cement clinker using a water spray means.

〔Example〕

An embodiment of the present invention will be explained with reference to FIG. In addition, the first
In the figure, the same members as in the conventional figure 3 are given the same reference numerals, and explanations are omitted unless necessary.

In the figure, 21 indicates a high-temperature air outlet for other heat utilization equipment such as raw material pulverizing and drying equipment, coal pulverizing and drying equipment, and waste heat power generation equipment; 21 indicates excess air discharged from the cooler 1 to the atmosphere;
A cooling fan n1 blows cooling air into the middle part of the cooler 1. A duct is used to circulate the air to the middle part of the cooler 1. 5 is a damper for adjusting the flow rate of air in the duct 21. G is for adjusting the temperature of the circulating gas. A duct for taking in cold air, γ is a damper provided in the duct 26 to adjust the air volume. The above-mentioned fan n1 is installed for blowing circulating gas into each air chamber, and dampers n', n', and U' for adjusting the air volume are installed at the inlets in the same row. The channel is a water spray device for adjusting the temperature of the clinker 6 discharged from the cooling device. In such a cooling system, the secondary air for combustion is normally 0, 8 to 1. ．． When collecting ONm"/kgcli and recovering high-temperature air usually 0.4 to 0.5 Nm37kgc11 from the high-temperature air extraction unit to other heat utilization equipment, part of the surplus gas discharged from the cooling device to the atmosphere. By adjusting the flow rate with the damper 5 through the duct 21 and blowing into the middle part of the cooler 1 with the cooling fan 22. In this case, the amount of circulating gas is about 0.5 Nm3/kycli.Normally, the damper n is used in a fully closed state.In Fig. 1, the exhaust gas circulation fans are designated by symbols 22 and 23. .2
Although three fans in No. 4 are shown, the number of fans is not necessarily three, and is determined according to the amount of recovered air extracted from the high-temperature air outlet. Further, when the exhaust gas is circulated, the temperature of the clinker 6 discharged from the cooling device generally rises, but in this case, water is sprayed onto the clinker by a water spray device path installed at the cooling device outlet to maintain an appropriate temperature. In addition, when the heat utilization equipment for the high temperature air extracted from the high temperature air outlet 0K stops, the damper 5 is fully closed and the damper n is fully open, stopping the circulation of the cooling device exhaust gas and cooling fans n, N5, Cold air is supplied from the duct valley to the same line, and the water spray equipment path is stopped.

In this case, it is the same as that shown in the conventional example (FIG. 3). Circulating gas is distributed to the cooling fans n, N5, and U by dampers 22', n', and U'. Since the cooler exhaust air after dust removal is used as the circulating gas, troubles with the circulation fan caused by high temperature dust can be prevented.

In this embodiment, as described above, a part of the surplus gas discharged from the cooling device to the atmosphere is taken out through the duct 21, and a cooling fan n which is a cooling air supply means for cooling the clinker 6 is used.
Since the clinker 6 is cooled, the temperature of the excess gas (high temperature air) passing through the exhaust port 5 and the dust collector 11 can be maintained at an appropriate high temperature, and the electric ratio can be maintained at an appropriate high temperature. The increase in resistance can be suppressed and the dust collection efficiency of the dust collector 11 can be maintained at a high level. In addition, the reduction in cooling efficiency for the clinker 6 caused by adding a portion of high-temperature surplus gas to the cooling air can be compensated for by lowering the temperature to an appropriate level by spraying water on the clinker 6 using a water spray device, which is rational as a whole. In other words, it is possible to obtain a clinker cooling device that has a well-balanced clinker cooling efficiency, dust collection efficiency, and utilization efficiency of high-temperature air after cooling.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects. That is, since the electrical resistivity value of clinker dust can be adjusted to an appropriate value, the dust collection efficiency of the electrostatic precipitator can be maintained at a high level, and dust emission regulations can be satisfied. At the same time, the temperature of the cement clinker discharged from the cooling device is lowered to an appropriate temperature by the water spray device, so that there is no problem with the operation of subsequent equipment. In addition, the high temperature air after cooling the cement clinker can be used for other purposes as before, without sacrificing convenience at all.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a cooling device as an embodiment of the present invention;
FIG. 2 is a diagram showing the relationship between the electrical resistivity of clinker dust and temperature, and FIG. 3 is an explanatory diagram of a conventional cooling device. 1... Cooler 2... Rotary kiln 3.
・・Kiln fan-1-+4・・Secondary air outlet・・Exhaust port 6・・Clinker 7・・Grate
8...Clinker outlet 9...Cooling air chamber
10...Cooling fan 11...Electric dust collector 12
...Exhaust fan 13...Transport aircraft addition...
High temperature air intake port 21... duct 22, Z3.24... cooling fan 22', 23', 24', 25... damper...
27...Damper...Water spray device

Claims (1)

[Claims] The high-temperature cement clinker discharged from the cement kiln is cooled with cooling air, and a portion of the high-temperature air generated by heat exchange with the cement clinker is recovered as a heat source for heat utilization equipment, and the remaining high-temperature air is used in an electrostatic precipitator. A cooling device for cement clinker that is released into the atmosphere after dust removal includes means for extracting a portion of the high-temperature air that is released into the atmosphere after dust removal and adding it to the cooling air, and water-cooling the cement clinker that is cooled by the cooling air and discharged. A cooling device for cement clinker, characterized in that it is equipped with a water spray means.