JP2000309810A - Method for controlling temperature of blast furnace top gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling the temp. of blast furnace top gas to that moisture in the blast furnace top gas at the furnace top part does not become the saturating state or higher. SOLUTION: The moisture content in the blast furnace top gas in an uptake tube is measured with a moisture meter 11 and this measured value and the moisture content in the saturating state at the upper part of the uptake tube, are compared and a spraying water flow rate till becoming the saturating state is obtd. On the other hand, the blast furnace top gas temp. in the uptake tube is measured with a thermometer 4, and this measured value and a regulating temp. at the upper part of the uptake tube are compared, and a spraying water flow rate for cooling till regulating temp. is obtd. These two spraying water flow rates are compared and the smaller side in these flow rates is set as the spraying water flow rate to an adjusting value 6 for adjusting the spraying water flow rate. Further, the spraying water flow rate is measured with a flow meter 13 arranged at the front of the adjusting valve 6, and while adjusting the opening degree of the adjusting valve 6 based on this difference between the measured value and the spraying water flow rate setting value, the cooling water is sprayed from a spraying water nozzle 3 to indirectly cool the blast furnace top gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of controlling the temperature of a blast furnace top gas, and more particularly, to controlling the water spray flow rate of a water spray nozzle based on the amount of water in the furnace gas and the temperature of the furnace gas. It belongs to the technical field of controlling the temperature of the blast furnace top gas for cooling the top gas.

[0002]

2. Description of the Related Art Blast furnace top gas is collected by a blast furnace exhaust gas riser and introduced into a dust catcher via a downcomer, where coarse dust is removed, and then fine dust is collected by a wet dust collector or a dry dust collector. Is excluded. The dust-removed furnace top gas is introduced into a furnace top power generation turbine to generate power, and then introduced into a hot blast stove or a gas holder. The temperature of the top gas introduced into the top power generation turbine is preferably higher in order to increase the amount of power generation.

[0003] When the temperature of the furnace top gas rises, the life of equipment such as a bell and a cross sonde installed on the furnace top is shortened, and when a dry dust collector (bag filter) is employed, the bag filter is not used. This will cause thermal damage to the filter cloth. Therefore, it is important to properly control the furnace gas temperature. In particular, as the pulverized coal injection amount increases, the furnace top gas temperature tends to increase.

[0004] As a method of controlling the temperature of the top gas, a method of spraying water on each part of the furnace top is generally adopted. However, it is necessary to confirm that the water spray is effectively working for cooling the top gas. is important. FIG. 3 shows an example of a conventional furnace top gas temperature control method. As shown in FIG. 3, water is directly sprayed from a water spray nozzle 9 provided at the top of the blast furnace to the furnace gas rising in the blast furnace to cool the furnace gas, and further, a water spray nozzle provided at the lower periphery of the lower part of the blast furnace exhaust gas riser 3 there is a method of controlling the temperature of the top gas, which indirectly cools the top gas rising in the riser by spraying water on the outer circumference of the blast furnace exhaust gas riser 2.

That is, the temperature of the top gas that has risen in the blast furnace is about 650 ° C. In order to lower this temperature, the temperature of the top gas that has risen is measured by a thermometer 7 installed above the watering nozzle 9. Based on this measured value, the temperature controller 8 sets the PI to a specified temperature, for example, 350 ° C at the lower part of the riser.
D calculation is performed to determine a watering flow rate, and the opening and closing of the control valve 10 is adjusted based on the watering flow rate to spray cooling water from the watering nozzle 9 to directly cool the furnace top gas. In order to further lower the furnace top gas temperature, the temperature of the furnace top gas that has risen is measured by a thermometer 4 installed above the riser pipe, and based on the measured value, a temperature controller 5 determines a specified temperature, for example, the upper part of the riser pipe. At 180 ℃
PID calculation is performed to obtain the watering flow rate, and the opening and closing of the control valve 6 is adjusted based on the watering flow rate to obtain the watering nozzle 3
From the blast furnace exhaust gas riser 2 to indirectly cool the furnace top gas.

[0006]

However, in the case where the emphasis is placed on cooling the furnace top gas and the flow rate of water sprayed from the water spray nozzle is adjusted as described above, if the amount of water sprayed is too large, When the water content in the gas becomes more than the saturated state, the water sprinkled does not evaporate and remains in the water state. The remaining moisture dissolves sulfurous acid gas and chlorine gas generated in the furnace, wets the refractory lining of the blast furnace top and riser, or soaks and reacts with the refractory to promote deterioration of the refractory. . In addition, the moisture dissolved in sulfurous acid gas, chlorine gas, or the like that has invaded through cracks in the refractory also corrodes the steel skin. Repair of the refractory lining at the top of the blast furnace or the riser cannot be performed until the blast furnace is rolled over, and preventing damage to the refractory lining is important for blast furnace operation.

Such a state occurs when there is an incompatibility in the performance of the water spray nozzle, the installation position of the water spray nozzle with respect to the flow of the furnace top gas, the flow rate of the water spray with respect to the flow rate of the furnace top gas, and the like. To prevent these inconsistencies, it may be possible to install many sensors, but it is difficult to accurately grasp information from many sensors. Therefore, there is a demand for a method of controlling the temperature of the furnace top gas by adjusting the flow rate of water sprayed from the water spray nozzle with a small number of sensors and evaporating all of the water sprayed so that the water remains in the water state.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. In a method for controlling the temperature of the top gas by spraying water from a water spray nozzle, the temperature of the top gas and the amount of water in the top gas are controlled. By measuring, the sprinkling flow rate from the sprinkling nozzle is adjusted accurately, and all the sprinkled water does not evaporate and remain in the water state, so that the water in the furnace top gas does not become saturated at the furnace top or more. It is an object of the present invention to provide a method for controlling a blast furnace top gas temperature.

[0009]

The gist of the present invention is to control the furnace gas temperature by spraying water from a water spray nozzle, and to measure the amount of water in the furnace gas in the furnace blast furnace exhaust gas using a moisture meter installed above the furnace gas riser. Is measured and the measured value is compared with the water content in the saturated state at the upper part of the riser to determine the watering flow rate until the state becomes saturated. Measure the gas temperature, compare this measured value with the specified temperature at the upper part of the riser pipe, find the water flow rate to cool down to the specified temperature, compare these two water flow rates, and adjust the smaller water flow rate, and adjust the water flow rate The control valve is set as the watering flow rate, and the watering flow rate is measured by a flow meter provided in front of the control valve.The blast furnace is adjusted while opening and closing the control valve based on the difference between the measured value and the watering flow setting value. Provided on the lower periphery of the exhaust gas riser The riser outer periphery by sprinkling cooling water from the water spray nozzle is a control method of blast furnace top gas temperature indirectly cool the cooled top gas.

In addition to the above-described method of controlling the temperature of the furnace top gas, the amount of moisture in the furnace top gas in the riser is measured by a moisture meter installed in the lower part of the riser. Compare the amount of water in the saturated state and determine the water flow rate until the saturated state is reached.On the other hand, install directly above the spray nozzle that cools the top gas by spraying water directly on the top gas that has risen in the blast furnace. Measure the gas temperature at the furnace top with a thermometer, compare the measured value with the specified temperature at the bottom of the blast furnace exhaust gas riser, determine the water flow rate for cooling to the specified temperature, compare these two water flow rates, and compare the smaller water flow rate The flow rate is set as a sprinkling flow rate in a control valve for adjusting the sprinkling flow rate, and the sprinkling flow rate is measured with a flow meter provided in front of the control valve, and the flow rate is adjusted based on a difference between the measured value and the sprinkling flow rate set value. Blast furnace top while adjusting valve opening and closing In a blast furnace top gas temperature controlling method of the water spray nozzles and sprinkling cooling water to cool directly the top gas which has been raised a blast furnace provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the water flow rate until the moisture in the furnace top gas at the temperature measurement site becomes saturated is the same as the water flow rate until the temperature at the temperature measurement site is cooled to a specified temperature. And spraying water from the watering nozzle based on the smaller watering flow rate to control the furnace top gas temperature. In other words, when the water flow in the furnace top gas at the temperature measuring part is smaller than the water flow rate until the water is saturated, the water flow rate before the water is saturated is less. If the furnace top gas temperature is controlled by the water spray flow rate until the temperature at the same temperature measurement site where the temperature is large is cooled to the specified temperature, the water that is excessively sprayed and cannot be evaporated remains in the water state.

When the water flow rate at which the temperature at the temperature measuring part is cooled to the specified temperature is smaller, there is less room for the water flow rate at which the temperature is cooled to the specified temperature. If the temperature of the top gas is controlled by the water flow rate until the moisture in the top gas at the same temperature measurement site is saturated, the water is excessively sprayed and the temperature of the top gas becomes too low. Therefore, control of the furnace top gas temperature is performed by comparing the sprinkling flow rate until the temperature at the temperature measurement site reaches the saturation state and the sprinkling flow rate until cooling to the specified temperature at the same temperature measurement site. Do with. However, if the moisture in the furnace top gas is above the saturation state or the furnace top gas temperature is lower than the specified temperature, it is not possible to spray more water to cool the furnace top gas.

As described above, by comparing the two watering flow rates and controlling the furnace top gas temperature based on the smaller watering flow rate, there is no water remaining in the water state,
The refractory lining at the top of the blast furnace and the riser does not deteriorate, and the moisture dissolved in sulfurous acid gas, chlorine gas, or the like that has penetrated from cracks in the refractory does not corrode the steel shell. Further, since the furnace top gas temperature can be maintained at the specified temperature, the furnace top power generation amount is also stabilized, and the thermal damage to the filter cloth of the dry dust collector can be avoided.

[0014]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the temperature of the furnace top gas rising from the blast furnace exhaust gas riser by spraying water on the outer periphery of the blast furnace exhaust gas riser 2 is two blast furnace exhaust gas risers 2 extending upward from the top of the blast furnace exhaust gas. The moisture meter 11 is installed at the connection point A. The reason is that when the furnace condition becomes unstable and the top gas temperature rises sharply, water is rapidly sprayed on the top gas, and in such a case, excessive water is temporarily generated. This is because the furnace top gas containing excess moisture collides with the side wall at a portion where the flow is bent and wets the portion. Therefore, the moisture meter is located at the junction A where the flow of the furnace top gas is bent.
11 are installed. As the moisture meter 11, a neutron moisture meter can be used.

The moisture content in the furnace top gas in the riser is measured by the moisture meter 11, and based on the measured value, PID calculation is performed by the moisture controller 12 to determine the watering flow rate until saturation. on the other hand,
The temperature of the furnace top gas in the riser is measured by a thermometer 4 installed at the upper part of the riser.
An ID calculation is performed to determine a watering flow rate until cooling to a specified temperature. Then, the signals of the two sprinkling flow rates are sent to the calculator 15.

An arithmetic unit 15 compares two sprinkling flow rate signals sent from the moisture controller 12 and the temperature controller 5 and calculates a sprinkling flow rate obtained by performing PID calculation on the smaller sprinkling flow rate signal. Set the watering flow rate to 14 The flow controller 14 controls opening and closing of the control valve 6 based on the set watering flow rate. A flow meter provided in front of the control valve 6
The water flow rate is measured at 13, and based on the difference between the measured value and the water flow rate set value, the flow controller 14 adjusts the opening and closing of the control valve 6 to increase the accuracy of the water flow rate from the watering nozzle 3. be able to. The watering nozzle 3 provided below the blast furnace exhaust gas riser while adjusting the opening and closing of the control valve 6 in this manner.
The temperature of the furnace top gas is controlled by indirectly cooling the furnace top gas by spraying cooling water from above to cool the outer periphery of the riser pipe.

[0017]

Embodiment 2 FIG. 2 shows a method of controlling the furnace top gas temperature shown in FIG.
16 is installed to improve the accuracy of the water flow rate from the watering nozzle 9. In other words, when the furnace condition becomes unstable and the temperature of the top gas rises sharply, water is rapidly sprayed on the top gas, and in such a case, the water temporarily becomes excessively water (moisture is more than saturated). There is a moisture analyzer here 16
It is important to measure the amount of water in the furnace top gas by installing a blast furnace in order to avoid damage to the refractory lining of the blast furnace top and the riser pipe. As the moisture meter 11, a neutron moisture meter can be used.

The moisture content in the furnace top gas in the riser is measured by a moisture meter 16, and based on the measured value,
D is calculated to determine the watering flow rate until the water is saturated. On the other hand, the temperature of the top gas at the top of the blast furnace is measured by the thermometer 7 installed above the watering nozzle 9, PID calculation is performed by the temperature controller 8 based on the measured value, and watering is performed until the temperature reaches the specified temperature. Find the flow rate. Then, the two sprinkling flow rate signals are sent to the computing unit 20.

The arithmetic unit 20 compares the two sprinkling flow rate signals sent from the moisture controller 16 and the temperature controller 9 and calculates the sprinkling flow rate obtained by performing PID calculation on the smaller sprinkling flow rate signal. Set to 19 as the set watering flow rate. The flow controller 19 adjusts the opening and closing of the control valve 10 based on the set watering flow rate. Further, a flow meter provided in front of the control valve 10
The sprinkling flow rate is measured at 18, and based on the difference between the measured value and the sprinkling flow rate set value, the flow controller 19 adjusts the opening and closing of the control valve 10 to increase the accuracy of the sprinkling flow rate from the sprinkling nozzle 9. be able to. While controlling the opening and closing of the control valve 10, the cooling water is sprayed from the water spray nozzle 9 provided at the top of the blast furnace to directly cool the furnace gas, thereby controlling the furnace gas temperature.

As described above, by providing the moisture meters 11 and 16, the amount of water in the top gas can be measured, and based on this, the water flow rate until the water in the top gas becomes saturated can be measured. You can ask. On the other hand, based on the temperatures measured by the thermometers 4 and 7, it is possible to determine the watering flow rate until the temperature of the temperature measuring part is cooled to the specified temperature. If the top gas temperature is controlled at the smaller flow rate by comparing the two flow rates, the top gas temperature does not exceed the specified temperature, and the water content in the top gas becomes more than the saturated state. Not even. Therefore, it is possible to prevent damage to the refractory lining of the blast furnace top and the riser pipe.

[0021]

As is apparent from the above description,
According to the present invention, since the temperature of the top gas can be controlled so that the water in the top gas does not become saturated or higher, the water directly sprayed on the top gas at the top of the blast furnace does not completely evaporate. Will not remain in the state. Therefore,
Water dissolved in sulfurous acid gas, chlorine gas, etc. does not wet or infiltrate the refractory lining of the blast furnace top and riser, and as a result, damage to the refractory and corrosion of the steel shell can be prevented .

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for controlling a blast furnace top gas temperature according to claim 1;

FIG. 2 is a diagram illustrating a method for controlling a blast furnace top gas temperature according to claim 2;

FIG. 3 is a diagram illustrating a conventional method for controlling a blast furnace top gas temperature.

[Explanation of symbols]

1: Blast furnace, 2: Blast furnace exhaust gas riser, 3: Sprinkler nozzle, 4
... thermometer, 5 ... temperature controller, 6 ... control valve, 7 ... thermometer,
8 ... temperature controller, 9 ... watering nozzle, 10 ... control valve, 11 ... moisture meter, 12 ... moisture controller, 13 ... flow meter, 14 ... flow controller,
15… Calculator, 16… Moisture meter, 17… Moisture controller, 18… Flow meter, 19… Flow controller, 20… Calculator.

Claims (2)

[Claims] In a method for controlling a furnace gas temperature by spraying water from a water spray nozzle, a moisture meter installed above a blast furnace exhaust gas riser is used to measure the amount of moisture in the furnace top gas in the riser, and this measured value is compared with the measured value. Compare the water content in the upper part of the riser with the saturated water content to determine the water flow until saturation, and measure the furnace top gas temperature in the riser with a thermometer installed on the upper part of the riser. Compare the value with the specified temperature at the top of the riser pipe to determine the watering flow rate for cooling to the specified temperature, compare these two watering flow rates, and set the smaller watering flow rate as the watering flow rate at the control valve that controls the watering flow rate. Further, the sprinkling flow rate was measured with a flow meter provided in front of the control valve, and provided on the outer periphery of the lower part of the blast furnace exhaust gas riser pipe while adjusting the opening and closing of the control valve based on the difference between the measured value and the sprinkling flow rate set value. Watering the cooling water from the watering nozzle A method for controlling the temperature of the blast furnace top gas, comprising cooling the outer periphery of the riser pipe and indirectly cooling the top gas. 2. In addition to the method for controlling a blast furnace furnace gas temperature according to claim 1, the amount of water in the furnace gas in the riser is further measured by a moisture meter installed below the riser. And the amount of water in the lower part of the riser in the saturated state to determine the water flow rate until the saturated state is reached.On the other hand, the water spray nozzle directly cools the furnace gas by spraying water directly on the furnace gas rising in the blast furnace. Measure the gas temperature at the top of the furnace with a thermometer installed above, compare this measured value with the specified temperature at the bottom of the blast furnace exhaust gas riser, find the water flow rate for cooling to the specified temperature, and compare these two water flow rates. The smaller sprinkling flow rate is set as a sprinkling flow rate in a control valve for adjusting the sprinkling flow rate, and the sprinkling flow rate is measured with a flow meter provided in front of the control valve,
While controlling the opening and closing of the control valve based on the difference between the measured value and the water flow setting value, cooling water is sprayed from a water spray nozzle provided at the top of the blast furnace to directly cool the furnace gas rising in the blast furnace. A method for controlling a blast furnace top gas temperature, characterized in that: