KR20010048808A - Controlling flame temperature and compensating furnace heat method of tuyere head when stopping pulverized coal injection - Google Patents

Abstract

PURPOSE: A method for compensating a furnace heat and controlling a combustion temperature is provided to control the combustion temperature of a front end of a tuyere not to be excessively increased when the pulverized coal supply is stopped, and compensate the furnace heat by automatically supplying cokes as the substitutional fuel by an amount of non-supplied pulverized coal. CONSTITUTION: A method for compensating a furnace heat and controlling a combustion temperature of a front end part of a tuyere when stopping the pulverized coal supply includes the steps of controlling a cold wind mixing control valve with a wind temperature value initially set in a wind temperature setting part(S2), continuously checking whether the supplying of pulverized coal is stopped(S3), detecting temperatures of a front end part of the tuyere before and after stopping of the pulverized coal and transmitting a wind temperature set value when the pulverized coal supply was stopped if yes(S4), controlling the cold wind mixing control valve according to the wind temperature set value at the time point when the pulverized coal supply was stopped while converting a pulverized coal supply mode to a pulverized coal supply stopping mode(S5,S6), checking whether the pulverized coal is supplied again(S7), controlling the cold wind mixing control valve according to a reset element while converting the pulverized coal supply stopping mode to the pulverized coal supply mode again if yes(S8,S9), and operating a time period of the coal supply stop and a non-supplied amount of the coal, and a coke amount to be supplied(S10).

Description

Control of combustion temperature and blast compensation at the end of the tuft hole at the time of pulverized coal injection {Controlling Flaming TEMPERATURE AND COMPENSATING FURNACE HEAT METHOD OF TUYERE HEAD WHEN STOPPING PULVERIZED COAL INJECTION}

The present invention controls the combustion temperature of the tip of the tufts that rise excessively when the pulverized coal supplied through the tuyere of the blast furnace is blown, and at the same time, the amount of pulverized coal that has not been blown is automatically supplied to the coke as an alternative fuel to compensate for the heat. The present invention relates to a combustion temperature control and a furnace compensation method in case of blown coal injection.

Generally, about 34 vents are provided in the case of a large blast furnace, and about 25 vents are provided in the case of a small blast furnace.

34 pulverized coal injection lances are installed in the tuyere, and the pulverized coal is blown into the furnace by air through the lance.

At this time, an oxy-coal blown pipe is connected to the pulverized coal lance to improve the combustibility of the pulverized coal and to cool the pulverized coal blown lance.

During the blast furnace operation, the combustion temperature at the tip of the tuyere should be controlled to about 2250 ± 100 ℃, but if the coal dust is stopped due to the problem of the coal dust blowing facility, the combustion temperature will be about 500 ℃ higher than when the coal dust is blown (60 tons per hour). .

If the combustion temperature at the tip of the tuyere is excessively high, it blocks the pores of the coke, which becomes the gas passage in the furnace, and impedes the passage of gas, thereby degrading the contents of the molten iron and lowering the productivity of the molten iron. Therefore, the combustion temperature at the tip of the tuyere is continuously controlled and managed because it hits the tuyere when re-injecting pulverized coal.

In the past, when pulverized coal was blown off, the work and humidity (steam) to block the hatched oxygen in the main building of the blower were temporarily added (about 15 g / Nm ³ ) to temporarily block the oxy-call entering the tuyere and purge the air in the line ( cooling is performed to prevent bending of the pulverized coal injection lance.

After that, determine the cause of pulverized coal blown out, and if re-blowing is started after measures, readjust the blocked oxygen, oxycall, and humidity as in the case of pulverized coal injection, and prevent the blast furnace deterioration sharply. The coke is additionally weighed and charged by identifying the time and amount of coal mined.

However, this method involves the following problems.

First, in order to reduce the combustion temperature at the end of the blowhole when the coal dust is blown off, the operator must manually block the oxycol in the oxygen-rich blowhole and additionally inject the humidity into the high-pressure air purge and blower main for cooling the oxycol blow-in pipe. There is inconvenience.

Second, when pulverized coal injection is stopped, excessive rise of combustion temperature of the blast furnace tip causes deformation of pulverized coal injection lance. Therefore, appropriate measures must be taken manually so that pulverized coal does not damage the blast holes during re-injection. It is inconvenient to continuously carry out complicated and difficult tasks such as downtime, compensation amount, and the amount of coke equivalent of calories.

Third, the excessive purge of air through the oxycoline when the pulverized coal injection is interrupted causes a problem of failure of the auxiliary equipment due to a decrease in the operating pressure of a plurality of pneumatic equipment installed in the facility.

Fourth, because oxygen is blown into the high temperature gas in the blast furnace as a gas having a high explosion limit, there is a high possibility of explosion if the blowing conditions are not satisfied when re-blowing after oxycol blowing.

The present invention was created in view of the various problems caused when stopping the pulverized coal injection as described above, when the pulverized coal injected into the blast furnace is blown by various factors, subsidiary oxygen, oxycall, humidity control It is possible to reduce the amount of hot air flow through the hot stove and increase the cold wind flow to control the combustion temperature at the tip of the blowhole as well as to prevent deformation of the pulverized coal injection lance and quickly and accurately The purpose of the present invention is to provide combustion temperature control and furnace compensation method in case of pulverized coal injection stop.

1 is a schematic diagram illustrating a blowing path supplied to a blast furnace;

2 is a flow chart illustrating a wind temperature control flow according to the present invention.

Explanation of symbols on the main parts of the drawings

1: blast furnace, 14: hot air temperature,

16: a funnel, 16a: a funnel tip.

An object of the present invention described above is a first step of controlling the cold air mixing control valve to the initial temperature set in the wind temperature setting system while the pulverized coal is blown into the pulverized coal blowing mode at the same time, and the blowing of the pulverized coal after the first step occurs 2nd step of continuously checking whether or not the powdered coal is not stopped in the second step, and if it is determined that the powdered coal is not stopped, the wind tunnel before and after immediately stopping the powdered coal injection through the instrumentation computer. A third step of detecting a tip temperature and communicating with a wind temperature setting system to transmit a wind temperature set value when the blowing is stopped; and after the third step, the blown wind temperature transmitted from the wind temperature setting system is switched to the pulverized coal blowing mode; A fourth step of controlling the cold air mixing control valve in accordance with a set value and whether or not pulverized coal is re-blown after the fourth step; In step 5 and, if the re-injected pulverized coal is not performed in the fifth step, and the re-injected pulverized coal is re-injected, the cold air mixed control valve is switched to the pulverized coal injection mode by communicating with the wind temperature setting system. The amount of coke to be blown is calculated by calculating the time and non-blown amount of the blown-out through the program embedded in the process computer after the sixth step of controlling to correspond to the reset value, and calculating the fuel cost of reducing the wind temperature accordingly. It is achieved by including the seventh step of deriving and weighing the raw materials and then adding the weighed coke to the blast furnace to further blow.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a system diagram illustrating a blowing path supplied to a blast furnace.

As shown, the cold air of about 200 ° C. sent from the blower 2 and the sub-oxygen 3 and the humidity control 4 are mixed, and the cold air valves 6 and 6a of the hot air path through the cold air line 5. 7) After passing through the heat storage chambers 8 and 8a and the combustion chambers 9 and 9a that have been heat-generated through combustion (7a), the temperature is raised to high temperature hot air of about 1200 ° C., followed by the hot air valve (11) and the hot air main pipe (13). ), And enters the blast furnace (1) through the tuyere (16).

Here, in order to make the cold air into a hot air of high temperature, one or two of the four units perform a mixed combustion of gas and air in the combustion chambers 9 and 9a, and then heat storage in the heat storage chambers 8 and 8a. The cold air is blown by the heat-generated furnace of the heat storage chambers 8 and 8a to make hot air of high temperature.

In other words, the 1,2 and 3 and 4 in parallel, but when the 1,2 is operating to control so that the 3,4 is in the standby state.

In other words, the cycle of combustion and heat storage in four of the hot stoves is automatically changed every one hour, and the hot air temperature 14 which has passed through the furnace accumulated in the three and four heat storage chambers 8 and 8a is set. If it is abnormal, open the cold air mixing control valve 12 on the trailing blower side of the three or four hot air furnace to mix the hot air and cold air in the mixed-cooling chamber 10 to lower the air temperature so that the hot air temperature 14 is controlled. .

When the blowing of the pulverized coal is stopped in this operation, the humidity (4), the oxygen enrichment (3), and the oxycol (18) are blown as before, and the combustion temperature is detected before and after the blowing hole tip 16a is stopped. The amount of air blown is checked in time series, and when the pulverized coal injection is stopped, the wind temperature setting value is automatically changed by the instrument computer to switch to the blowing mode. At the same time, two mixed cold air control valves 12 and 12a are opened, and pulverized coal injection is performed. It is managed by the same combustion tip 16a combustion temperature before stopping.

After the processing is completed, when the pulverized coal is re-blown, the instrument temperature setting value of the instrumentation computer is automatically changed to the set value before the blow-in progression, and is switched to the pulverized coal injection mode, and at the same time, one of the two cold air mixing control valves 12 (12a) Valves 12a are closed and only the remaining valves 12 are opened to control the hot air temperature 14.

At the same time, considering that 60 tons per hour is blown, the process computer calculates the amount of pulverized coal that has not been blown in time series from the blowing stop point, and determines the input amount of coke through the calculated value to control the injection after the automatic basis weight.

2 is a flowchart illustrating a wind temperature control flow according to the present invention.

As shown, when the pulverized coal is blown, it is operated in the pulverized coal blowing mode which is controlled to the temperature set by the air temperature setting system (S1).

The pulverized coal injection mode maintains the air temperature through a cold air mixing control valve in order to maintain the initial value set in the air temperature setting system (S2).

While the pulverized coal is being blown, it is continuously determined whether the blowing is stopped by various factors (S3).

If the pulverized coal injection is not stopped in the determination process, the process of controlling the wind temperature while maintaining the pulverized coal injection mode is repeated.

If the pulverized coal injection is stopped, the instrumentation computer immediately calculates the tip temperature of the tufts before and after the pulverized coal is stopped, and at the same time communicates the wind temperature setting value according to the pulverized coal injection with the wind temperature setting meter (S4).

Subsequently, at the same time, the changed wind temperature setting value is received from the wind temperature setting system and is switched to the pulverized coal blowing stop mode and wind temperature control is performed to maintain the corresponding temperature value (S5).

Accordingly, the cold air mixing control valve is also controlled in accordance with the set-change wind temperature value (S6).

Then, it is continuously judged whether or not pulverized coal is re-injected. If it is judged that re-injection of pulverized coal is not achieved, the cycle of continuously operating the wind temperature set in the pulverized coal injection mode is repeated until the injection is performed, and When the blowing is confirmed, the instrumentation computer immediately transmits / receives the wind temperature setting system and changes to the wind temperature value at the time of blowing the pulverized coal, and switches to the pulverized coal blowing mode (S7) (S8).

In accordance with the switching to the pulverized coal injection mode, the cold air mixing control valve is also controlled to open and close corresponding to the changed wind temperature set value (S9).

Subsequently, the process computer calculates the unblended amount by time-series calculation of the time when the pulverized coal is stopped, and converts it to the fuel cost to be additionally charged, and finally converts the amount of coke to be additionally injected. (S10).

The amount of coke calculated in the process is based on the control of the process computer in the raw material weighing system to weigh the additional blown coke amount (S11).

After that, the coke is further blown (S12).

As such, when the pulverized coal is stopped, it maintains the existing equipment without arbitrarily adjusting the equipment as before, while controlling the air temperature through the cold air mixing control valve and additionally adding fuel corresponding to the pulverized coal quantity not injected. By automatic supply, it is possible to easily maintain the temperature at the tip of the tuyere, and at the same time compensate for the heat.

The following equations and tables show specific numerical values for the above-described air balloon tip combustion temperature control as an example, and also provide a basis for calculating a compensation amount for thermal compensation according to the amount of pulverized coal.

Combustion temperature value of the tip of the tuyere according to the change of various operation index Item / Classification Set value Adjusted value Blow-out tip combustion temperature change Wind temperature 1200 ℃ / hour ± 10 ℃ Set Value ± 8.4 ℃ Pulverized coal 55 tons / hour ± 1 ton setting value ± 8.0 ℃ Moisture 15 g ／ Nm ³ ± 5 g setting value ± 30.0 ° C Oxygen 15000 Nm ³ / hr ± 1000 Nm ³ Setpoint ± 16.0 ° C

According to Table 1, it can be seen that the combustion temperature change at the tip of the tuyere varies and varies considerably due to various operating indexes such as wind temperature, pulverized coal input, humidity (humidity), and oxygen enrichment.

Therefore, the air temperature set value and the combustion temperature management at the tip of the air vent according to appropriate control of the correlation when pulverized coal injection is stopped are shown in Table 2 below.

Wind temperature in normal operation ℃ Wind temperature at the time of pulverized coal cut Blown amount change (CUT time) ton Humidity (g ／ Nm ³ ) Oxygen (Nm ³ / hour) Combustion temperature (℃) 1200 1080 20 → 0 30 5000 2351 1200 1060 25 → 0 30 6000 2348 1200 1010 30 → 0 25 7000 2349 1200 990 35 → 0 25 8000 2346 1200 950 40 → 0 20 9000 2356 1200 920 45 → 0 20 10000 2344 1200 860 50 → 0 15 12000 2350 1200 820 55 → 0 15 15000 2357 1200 780 60 → 0 10 17000 2354 1200 750 65 → 0 10 17000 2355 1200 720 70 → 0 10 19000 2357

According to Table 2, the air temperature set value is managed in close proximity to the operation management temperature of the air port tip 2200 ± 100 ℃.

In the normal operation, 60 tons of pulverized coal per hour is continuously blown, so the combustion temperature at the tip of the tuyere is stopped by Equation 1 below when it is stopped.

Here, VO2 is oxygen injection amount / 60 / air volume, W is pulverized coal injection amount * (1000000/60) * air volume.

Table 3 below is a fuel cost conversion of the coke amount due to a decrease in wind temperature when the pulverized coal injection is stopped.

If blowing stop occurs while blowing 60 tons / hour of pulverized coal, the wind temperature should be controlled at 1200 ℃ to 2250 ± 100 ℃, which is the target value. In terms of air temperature, -1 kg / TP is -42 kg / TP when the wind temperature is -10 ° C, and it is 2.52 tons since it is 60 kg per 1 kg / TP.

However, more heat compensation is required to rise in low heat conditions (e.g. approximately twice as much compensation), which requires about 5.04 tons, which is twice the 2.52 tons, to compensate for the coke charged to the top of the table. As explained in Supplementary Note 3, the average divided by 6.0 charges per hour (CHARGE) is required.

Pulverized coal injection Normal wind temperature (A) Pulverized coal cut wind temperature (B) Deviation (A-B) Conversion to fuel costs Coke equivalent Trip pay compensation 20 → 0 1200 1080 -120 12 + α 1.44 1.44 / 6 = 0.24 25 → 0 1200 1060 -140 14 + α 1.88 1.88 ／ 6 = 0.31 30 → 0 1200 1010 -190 19 + α 2.28 2.28 ／ 6 = 0.38 35 → 0 1200 990 -210 21 + α 2.52 2.52 / 6 = 0.42 40 → 0 1200 950 -250 25 + α 3.0 3.0 / 6 = 0.5 45 → 0 1200 920 -280 28 + α 3.36 3.36 ／ 6 = 0.56 50 → 0 1200 860 -340 34 + α 4.08 4.08 ／ 6 = 0.68 55 → 0 1200 820 -380 38 + α 4.32 4.32 / 6 = 0.72 60 → 0 1200 780 -420 42 + α 5.04 5.04 ／ 6 = 0.84 65 → 0 1200 450 -450 45 + α 5.40 5.40 / 6 = 0.9 70 → 0 1200 720 -480 48 + α 5.76 5.76 / 6 = 0.96

As described in detail above, the method for controlling the combustion temperature at the tip of the tufts and the furnace compensation method when stopping the pulverized coal injection according to the present invention provides the following effects.

First, when pulverized coal injection is stopped, the combustion temperature at the tip of the tuyere does not need to perform additional and complicated operations such as oxygen enrichment, oxy-call blocking, purging air to the blowing lance, and randomly increasing humidity, thereby improving work efficiency.

Second, by controlling the combustion temperature at the tip of the tuyere naturally, it is possible to prevent the rise of silicon in the molten iron component to obtain a good molten iron, and to prevent the blow lance deformation and to perform a stable pulverized coal blowing operation.

Third, when the pulverized coal injection is stopped, the pulverized coal quantity is not calculated automatically and the replacement fuel is injected immediately to create the effect of stabilization of the furnace and improvement of aging.

Claims (1)

A first step of controlling the cold air mixing control valve to the wind temperature value initially set in the wind temperature setting system as the pulverized coal enters the pulverized coal injection mode at the same time; A second step of continuously checking whether or not the injection of pulverized coal has occurred after the first step; If it is determined in the second step that the fine coal injection is not stopped, the flow is cycled to the first step, and if it is determined that the fine coal injection is stopped, the wind blowing tip temperature is detected immediately before and after the fine coal injection is stopped through the instrumentation computer and communicated with the wind temperature setting meter. A third step of transmitting the wind temperature setting value of the city, A fourth step of controlling the cold air mixing control valve according to the blowing temperature setting value transmitted from the wind temperature setting system while switching to the pulverized coal blowing stopping mode after the third step; A fifth step of checking whether the pulverized coal is re-blown after the fourth step; If the re-injection of pulverized coal is not performed in the fifth step, if the re-injection is performed in the fifth step, if the re-injection is performed, the pulverized coal injection mode is re-switched by communicating with the air temperature setting system and the cold air mixed control valve is controlled to correspond to the reset value. The sixth step After the sixth step, a program embedded in the process computer is used to calculate the stopped time and non-blown amount, calculate the fuel cost according to the decrease in wind temperature, derive the amount of coke to be blown, and weigh the raw material after the basis weight of the coke. The combustion temperature control and furnace compensation method of the wind blowing tip at the time of stopping the pulverized coal injection, characterized in that it comprises a seventh step to further blow through the top of the.