JPS60128206A - Device for recovering energy of blast furnace gas - Google Patents

Abstract

PURPOSE:To provide the titled device which requires hardly maintenance and running costs by providing a heater and heat accumulator between a dust catcher and a bag filter and administrating thoroughly the temp. of the gas entering the bag filter. CONSTITUTION:When the temp. of the top gas of a blast furnace 1 is lower than the temp. in the stationary state, the temp. attains a dew point region and therefore a heater 9 provided behind a dust catcher 2 is actuated to increase the temp. of the gas and to maintain the same at the dew point or above. When the temp. of the blast furnace gas increases sharply to, for example, >=1,000 deg.C owing to blow-by, etc., the heat energy of the gas is accumulated by a heat accumulator 10 provided before a bag filter 3. The temp. of the gas in the inlet of the accumulator 10 fluctuating periodically according to the timing of charging the raw material to the furnace 1 even in an ordinary gas temp. range is made uniform by the accumulation of the heat energy in the accumulator 10 and heating. The gas maintained at the uniform temp. is fed via the filter 3 to a turbine 4 so that the energvy of the blast furnace gas is recovered at all time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an energy recovery device for blast furnace gas.

Conventionally, a dust collection system using a bag filter has been put into practical use as a gas cleaning system for energy recovery from blast furnace gas. FIG. 1 shows a block diagram of a blast furnace gas energy recovery apparatus having a conventional bag filter dust collection system. In the figure, 1 is a blast furnace, and 2 is a dust catcher 1 for collecting coarse particles of gas generated in the blast furnace 1.
Reference numeral 6 denotes a bag filter using cloth, which is installed after the dust catcher 2.

The gas generated in the blast furnace 1 passes through the dust catcher 2 and the bag filter 6 and is immediately led to the furnace top pressure power generation turbine 4, where the pressure energy of the blast furnace gas is recovered. 5
The pressure of the gas flowing into the turbine 4 is controlled by letting a part of the blast furnace gas flow through the septum valve.

In an energy recovery device having such a dust collection system, in order to protect the bag filter 6 from sudden increases in the temperature of blast furnace gas such as canes and atriums, for example, the first
As shown in the figure, a water sprinkling device including a sensor 6 for detecting the temperature of the inlet gas of the bag filter 6, a water sprinkling valve 7 for sprinkling cooling water, and a water sprinkling nozzle 8 is installed upstream of the dust catcher 2.

However, there are two major problems with energy recovery systems that use water sprinklers to counter the rise in blast furnace gas temperature.

First, since the bag filter 5 uses cloth with low heat resistance, the inlet gas temperature of the bag filter 3 must be strictly limited. Therefore, in order to prevent the water spray nozzle 8 from clogging in the coarse B gas, it is necessary to constantly purge. In addition, in order to maintain the water spray control function perfectly for a long period of time, it is necessary to keep the water sprinkler pump running and on the moving body side at all times. This results in large equipment costs and operating costs.

Second, in a bag filter dust collection system equipped with a water sprinkler, there is less heat storage), and even with normal fluctuations in the furnace top gas temperature, it is almost impossible to equalize the temperature, and the sudden change in gas temperature This is especially true when it rises. Therefore, when the gas temperature rises, it is necessary to lower the gas temperature by sprinkling water, and the thermal energy of the gas is significantly lost due to the latent heat of vaporization at this time, resulting in a decrease in energy recovery efficiency.

The object of the present invention is to provide a blast furnace gas energy recovery apparatus having a dry dust collection system that solves the above-mentioned problems.

The tube furnace gas energy recovery device of the present invention has a heating device that increases the gas temperature when the gas temperature decreases, in which the blast furnace top gas is distributed from the furnace top to the blast furnace gas holder. It consists of a dry heat storage device that absorbs the sensible heat of the gas when the gas temperature rises abnormally, a bag filter that collects gas dust, and a gas turbine that is driven by the gas that has passed through the bag filter. .

This invention will be explained based on examples.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 indicate the same components. 9 is a heater installed after the dust catcher 2,
Reference numeral 10 denotes a heat storage device installed after the heater 9, and the heater 9, for example, as shown in FIG. It consists of a compressed air supply pipe 14 and a combustion chamber 15. When heating blast furnace gas, a part of the blast furnace gas is extracted and compressed by a compressor 13 to increase the gas pressure, and then mixed with compressed air supplied from the compressed air supply pipe 14 to form a mixed gas. , this mixed gas is combusted in the combustion chamber 15 to supply combustion energy to the blast furnace gas.

For example, as shown in FIGS. 4(a) and 4(b), the heat storage device 9 has a heat storage material 16 such as a brick steel material arranged in the gas flow path, and the gas flow rate is set to 4.5 mm to prevent dust from accumulating and sticking. 0/
, C or higher, and the gas passage is designed to be vertical. FIG. 4(a) is a longitudinal sectional view of the heat storage device 9, and FIG. 4(b) is a sectional view taken along line A-A in the figure. . □゛Next, the operation of this embodiment will be explained.

Figure 5 shows the temperature characteristics of blast furnace gas. The temperature of blast furnace gas is usually 100℃ to 150℃ on average, as shown in figure (a).
℃G range, but considering past operating results of blast furnaces, during low fuel ratio operation, the temperature drops to 50 to 60℃ as shown in Figure (B), and when operating with all coke, etc. When operating at a high fuel ratio, as shown in the figure ←
The temperature rises from 50℃ to 200℃. Furthermore, the temperature in the atrium sometimes rises to 1000°C for a short period of time as shown in the figure.

Although the gas temperature fluctuates over a wide range in this way,
When the gas temperature becomes low, it reaches the dew point range, so if the filter cloth becomes clogged due to dew condensation, it becomes a fatal Vi defect for the bag filter 6.

To prevent this, use a dust catcher.
A heater 9 is installed after the gas temperature 2, and when the gas temperature drops, the heater 9 operates to raise the gas temperature and maintain it above the dew point temperature.

□In order to control the gas temperature at the outlet of the heater 9, as shown in Figure 6,
A control block diagram in which a temperature sensor 17 is installed between a heater 9 and a heat storage device 10 is shown. The temperature sensor 17 constantly detects the gas temperature at the outlet of the heater 9, and when the gas temperature falls below 60°C, the heater 9 is started and the bag filter 6 is removed.
The temperature of the gas entering the tank should be above the dew point temperature.

In addition, when the blast furnace gas temperature suddenly rises to over 1000℃ due to abnormal furnace conditions such as in the atrium, and even under normal conditions, when the gas temperature rises due to the timing of charging raw materials to the blast furnace, the bag The thermal energy of the gas is stored in a heat storage device 10 installed in front of the filter 6.

Fig. 7) shows the inlet gas temperature distribution of the regenerator 10 shown in Fig. 4 when the blast furnace gas temperature rises rapidly due to the atrium, and (e) shows the outlet gas temperature distribution of the regenerator 10. shows. As is clear from the figure, blast furnace gas at an initial temperature of 150°C is blown through for 10 minutes at the inlet of the regenerator 10.
Even if the temperature reaches 00°C, thermal energy is stored in the heat storage device 10, so the gas temperature at the outlet of the heat storage device 10 gradually rises inside the atrium, reaching a maximum temperature of about 250°C. After that, the gas temperature gradually decreases. Therefore, since the maximum temperature of the gas entering the bag filter 3 is suppressed, the bag filter 6 can be protected.

' Furthermore, even in the normal gas temperature range, the gas temperature at the inlet of the heat storage device 10 fluctuates periodically, as shown in FIG.

It is possible to equalize this fluctuation in gas temperature by storing and dissipating thermal energy in the heat storage device 10 as shown in FIG. can.

The heater 9 and the heat storage 10 are installed between the dust catcher 2 and the bag filter 6 to perform dry dust collection of the blast furnace gas. can be supplied.

As described above, according to the present invention, by installing the heater and the heat storage device between the dust catcher and the bag filter, the temperature of the gas entering the bag filter can be sufficiently controlled, resulting in maintenance and running costs. It is almost unnecessary and can protect the bag filter stably for a long period of time. Furthermore, since the regenerator equalizes gas temperature fluctuations, the gas temperature entering the furnace top pressure power generation turbine is equalized, which has the effect of improving the energy recovery efficiency of the turbine.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of a conventional blast furnace gas energy recovery system, Figure 2 is a professional diagram showing the configuration of an embodiment of this invention, and Figure 6 is a schematic configuration diagram of a heater. 4. Figure 4 (a) is a longitudinal cross-sectional view of the heat storage device, and (b) is the line A-A in figure (a).
Fig. 5 is a temperature characteristic diagram of blast furnace gas, Fig. 6 is a control block diagram of the heater, Fig. 7 is a gas temperature distribution diagram when the atrium is open, and Fig. 8 is a diagram showing the periodic fluctuations of gas temperature. FIG. 3 is a gas temperature distribution diagram when 1... Blast furnace, 2... Dust catcher, 6... Bag filter, 4... Furnace top pressure power generation turbine, 5...
・Septum valve? ... Heater, 10... Heat storage device.゛Deputy 9P Physician San Kimura M Fig. 1 Fig. 113 @ Fig. 4 Fig. (0) ・ Fig. 5 Ichi 6th 71st! 1st time - 8th palanquin - Ichirei 1 line Seki

Claims (1)

[Claims] In order to guide the blast furnace top gas from the top of the furnace to the blast furnace gas holder,
In a line that has a dust collection system equipped with a bag filter after the dust catcher, a heater is installed that raises the gas temperature when the gas temperature drops, and a heater that increases the gas temperature when the gas temperature rises abnormally. A blast furnace gas energy recovery device is equipped with a dry heat storage device that absorbs sensible heat, a back filter that collects gas dust, and a dry gas turbine that is driven by gas.