KR20030049738A - Circulation Gas Control System Of CDQ and Method Thereof - Google Patents

Abstract

PURPOSE: A system for controlling circulation gas constituents of CDQ is provided to automatically control air blowing volume for controlling the circulation gas constituents in CDQ adjusting to operation circumstances, and a method for controlling the circulation gas constituents of CDQ is provided. CONSTITUTION: In a CDQ (coke dryer quenching) for quench cooling coke of high temperature discharged from coke oven, the system for controlling circulation gas constituents of CDQ comprises an operation control part for calculating theoretic air volume for controlling the circulation gas constituents from information on circulation gas constituents inside the CDQ and air blowing volume blown into the CDQ, calculating correctional coefficient through analysis of actual results of the air blowing volume, and determining a target air blowing volume, wherein a nitrogen blowing pipe capable of blowing nitrogen for cooling is installed at the entrance of a boiler(6) for the CDQ. In a method for controlling circulation gas constituents of CDQ for quench cooling coke of high temperature discharged from coke oven, the method comprises the steps of measuring air blowing volume into the CDQ and analyzing circulation gas constituents in the CDQ; calculating theoretic air volume for controlling the circulation gas constituents, calculating correctional coefficient through analysis of actual results of the air blowing volume, and determining a target air blowing volume; and controlling the air blowing volume so that air as much as the target air blowing volume is blown into the CDQ.

Description

Circulation Gas Control System Of CDQ and Method Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coke dry fire extinguishing system, and more particularly, to a circulating gas component control system and a method of controlling a coke dry fire extinguishing system for automatically adjusting an appropriate amount of air blowing for adjusting a circulating gas component in a coke dry fire extinguishing system.

In the steelmaking process, coke dry fire extinguishing equipment (CDQ; Cold Dry Quenching) is a facility for cooling and extinguishing coke that has been dry-dried in a coke oven using inert gas.

The circulating gas, which consists of H ₂ and CO from red coke, and CO converted from CO ₂ by incomplete combustion of coke, increases in concentration during the circulation of boilers and chambers in which red coke is stored. ₂ and CO gases are highly explosive and need to be strictly controlled at an appropriate concentration. For this purpose, it is common to incinerate these components by introducing air from the outside.

Conventionally, the operator of a fire extinguishing facility directly controls the concentration of H ₂ and CO gas by directly investigating the components of the circulating gas and then determining the appropriate amount of air blowing by experience and blowing outside air. There has been a problem that it is difficult to operate a stable facility with a target component due to the increased work load according to the need.

In particular, when the excess air is blown without determining the correct amount of air blowing, there is a problem that there is a high risk of burning not only H ₂ and CO gas in the circulating gas but also coke.

The present invention is to solve the problems as described above, the purpose of the circulating gas of the coke dry fire extinguishing equipment for automatically controlling the air blowing amount for adjusting the circulating gas components in the coke dry fire extinguishing equipment to suit the operating conditions A component control system and method are provided.

1 is a view schematically showing a configuration of a coke dry fire extinguishing system to which a circulating gas component control system according to the present invention is applied;

2 is a configuration diagram of a circulating gas component control system of a coke dry fire extinguishing system according to the present invention;

<Explanation of symbols for the main parts of the drawings>

1: coke 2: pre-cooling chamber

2a: Air blowing line 2b: Air blowing control valve and flow meter

3: cooling chamber 3a: air blowing line

3b: Air intake flow control valve 3c: Air intake flow measurement flowmeter

4: duct 5: primary dust collector

5 ': secondary dust collector 6: boiler

7: circulation fan 8: line

9: circulating gas component analyzer 10: DCS computer

20: operation control unit 30: CRT display

The circulating gas component control system of the coke dry fire extinguishing system according to the present invention for achieving the above object, in the coke dry fire extinguishing equipment for extinguishing and cooling the high temperature coke discharged from the coke oven, the circulation inside the coke dry fire extinguishing equipment Operation control unit for calculating the theoretical air amount for adjusting the circulating gas component from the air blowing amount information blown into the gas component and the coke dry fire extinguishing equipment, calculating the correction coefficient by analyzing the air blowing amount performance, and determining the target air blowing amount It is characterized by that it contains.

Here, the nitrogen inlet pipe for blowing the cooling nitrogen to the boiler inlet of the coke dry fire extinguishing facility may be provided.

On the other hand, the method for controlling the circulating gas component of the coke dry fire extinguishing system according to the present invention, in the method for controlling the circulating gas component of the coke dry fire extinguishing system for extinguishing and cooling high temperature coke discharged from the coke oven, the air in the coke dry fire extinguishing facility Measuring a blow amount and analyzing a circulating gas component; Calculating a theoretical air amount for adjusting the circulating gas component, calculating a correction coefficient through analysis of the performance of the blown air amount, and calculating a target air blow amount; And controlling an air blowing amount such that the air as much as the target air blowing amount is blown.

Here, the theoretical air amount is characterized by being calculated by the equation (1).

A _{_need} = (CO _{_flow} * 0.5 + H _{2_flow} * 0.5) / 0.21 ----- (Equation 1)

(In the formula, A is _{_need} theoretical amount of air, CO _{_flow} necessary circulation amount of CO gas, H _{2_flow} to incineration of H ₂ is the amount of the circulation gas to be incinerated.)

In addition, the correction coefficient is characterized in that it is calculated by the equation (2).

K _ff = (1.0-K _fn ) ----- (Equation 2)

Where K _ff is the correction factor and K _fn is Where K _fx = CO _{n-x + 1} -CO _nx and CO _n is the closest circulating gas component analysis at the present time.)

In addition, the target air blowing amount is characterized in that it is calculated by equation 3.

_{_F} = A + A A _{_b _need ff} * K * K _fp ----- (Equation 3)

(In the formula, A _{_f} is a target air intake amount, the amount _{_b} A conventional air intake, A _{_need} the theoretical air quantity, K _ff is a correction factor, K _fp is a plant characteristic coefficient.)

In addition, when the boiler inlet side temperature of the coke dry fire extinguishing facility is more than the critical temperature blowing step for cooling nitrogen may be further included.

Here, the nitrogen injection amount is characterized in that calculated by the formula 4.

V _N = [(T _p -T _t ) * Circ _{_flow} ] / (T _p -T _N ) ----- (Equation 4)

Where V _N is the nitrogen injection, T _p is the current temperature, T _t is the target temperature, T _N is the nitrogen temperature, and Circ _{_flow} is the circulating gas flow.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

First, the circulating gas component control system of the coke dry fire extinguishing system according to the present invention will be described.

The glowing coke extruded from the coke oven is charged into a coke dry fire extinguishing facility as illustrated in FIG. 1 and then contacted with a circulating gas to be cooled down and then discharged.

Specifically, the precooling chamber 2 in which the high temperature red coke 1 is primarily cooled in the upper side of the coke dry fire extinguishing facility, and the air for blowing air from the outside into the precooling chamber 2 A blowing line 2a, an air blowing control valve and a flow meter 2b are provided. Then, the lower side of the pre-cooling chamber (2) and the cooling chamber (3) is a formal coke-cooled fire extinguishing, and the air blowing line (3a) which is connected to the duct (4) to be a passage for blowing air from the outside And an air intake amount control valve 3b and an air intake amount flow meter 3c attached thereto.

In particular, the duct 4 is passed through the cooling chamber 3 to the outside to distribute the circulating gas, the intermediate point of the duct 4 has a primary dust collector 5 for filtering foreign matter in the circulating gas It is provided, and the boiler 6 which adjusts to the temperature which can produce | generate steam using a high temperature circulating gas and cools coke again when it passes this primary dust collector 5 is installed.

In addition, a secondary dust collector 5 'is provided after passing through the boiler 6, and a circulation fan 7 for circulating the circulating gas in the duct 4 back to the cooling chamber 3 is provided. In the middle of the line 8 from 7) to the cooling chamber 3, a circulating gas component analyzer 9 for analyzing the components of the circulating gas is provided.

Therefore, the high temperature red coke 1 is cooled and extinguished by the circulating gas in the precooling chamber 2 and the cooling chamber 3, and the circulating gas receives heat obtained by heat exchange with the red coke 1 and the boiler 6 It is delivered to and cooled again to function to extinguish coke (1). At this time, the heat exchanged high temperature circulating gas is collected in the primary dust collector 5 through the duct 4 and introduced into the boiler 6, and then again collected in the secondary dust collector 5 ′ to the circulation fan 7. By circulation.

The coke dry fire extinguishing facility is controlled by a control device commonly referred to as a display control system (DCS) computer. In the present invention, as shown in FIG. 2, the operation control unit 20 is added to the DCS computer 10. I am doing it.

That is, the DCS computer 10 controls the circulating gas component analyzer 9, the air intake measurement flow meter 3c, and the air intake amount control valve 3b, and the circulation analyzed by the circulating gas component analyzer 9 The calculation control unit 20 calculates the theoretical air amount for adjusting the circulating gas component based on the information on the gas component and the current blowing air, the correction coefficient through the performance analysis of the blowing air amount, and the target air blowing amount. By transmitting to 10), the air blowing amount control valve 3b causes the appropriate amount of air to be blown.

In addition, the operation control unit 20 is connected to the CRT display 30, the facility driver can easily grasp the facility operation status.

Here, the calculation method of the theoretical air amount, the correction coefficient, and the target air blowing amount will be described in detail in the control method described later.

On the other hand, the air blown into the dry fire extinguishing facility not only incinerates H ₂ and CO gas, but also the temperature of the circulating gas circulated to the boiler 6 by incineration of powdered coke has a critical temperature (for example, experience value during actual operation). The furnace may rise excessively above 980 ° C.) and damage the boiler 6. To prevent this, a thermometer 6a is installed at the inlet of the boiler 6 and cooling nitrogen is introduced into the duct 4. A nitrogen blowing line 6b for blowing may be provided.

Next, a method of controlling a circulating gas component of a coke dry fire extinguishing system according to the present invention will be described.

First, the circulating gas should be managed with CO 4% or less, H ₂ 2% or less, O ₂ 1% or less, and these components are easily incinerated at high temperature, so they are adjusted by blowing air (O ₂ ) and incineration. CO and H ₂ are adjusted at the same time. Since hydrogen is incinerated first, hydrogen is automatically managed when CO concentration is controlled.

The combustion equation for adjusting the composition of the circulating gas is as follows.

CO + 1/2 O ₂ ⇒ CO ₂ + 67.56 Kcal

H ₂ + 1/2 O ₂ ⇒ H ₂ O + 57.6 Kcal

That is, oxygen in the air incinerates hydrogen and CO components in the circulating gas and converts them into inert gas. If H ₂ and CO are higher than the concentration to be controlled, the amount of air blown to be controlled is reduced. The amount of air blown to adjust the component to be managed depends on the circulating gas flow rate and the content of the ingredient. That is, even at the same concentration, the required air amount varies depending on the flow rate of the circulating gas.

In order to determine the amount of air to be blown, the theoretical air amount required for the composition adjustment is calculated based on the circulating gas flow rate and concentration. Also, in actual operation, it may be slightly different from the control by the theoretical air amount, so that the correction factor is obtained by analyzing how much the amount of the injected air can adjust the components of the circulating gas, and the amount of air to be blown is determined by these two equations. In other words, it analyzes the pattern of changing the components of the circulating gas due to the change in operating conditions and use it to determine the air intake amount.

In order to calculate the required theoretical air amount according to the components of the circulating gas, first, the amount of H ₂ and CO contained in the circulating gas to be incinerated is calculated based on the following equation.

CO _{_flow} = Circ _{_flow} * (CO _{_ratio} -CO _{_crit} )

H _{2_flow} = Circ _{_flow} * (H _{2_ratio} -H _{2_crit} )

Here, CO _{_flow} is CO amount, Circ _{_flow} is circulating gas amount, CO _{_ratio} is CO analysis value, CO _{_crit} is CO ingredient management standard value, H _{2_flow} is H ₂ quantity, H _{2_ratio} is H ₂ analysis value, H _{2_crit} is H ₂ ingredient management standard value The unit of H ₂ and CO amount is Nm ³ / Hr (N is Normal).

Since the required theoretical air volume is the flow rate for incineration of H ₂ and CO, it is calculated by the following equation by the combustion equation and the ratio of nitrogen and oxygen in the air.

O _{2_need} = CO _{_flow} * 0.5 + H _{2_flow} * 0.5

A _{_need} = O _{2_need} / 0.21 = (CO _{_flow} * 0.5 + H _{2_flow} ) * 0.5 / 0.21

As a result, the theoretical air amount A _{_need} is expressed as in Equation 1.

A _{_need} = (CO _{_flow} * 0.5 + H _{2_flow} ) * 0.5 / 0.21 ----- (Equation 1)

Here, A _{_need} is the amount of theoretical air required, CO _{_} flow is the amount of CO to be incinerated in the circulating gas, H _{2_flow} is the amount of H ₂ to be incinerated in the circulating gas (unit: Nm ³ / Hr).

However, in actual operation, it is difficult to precisely adjust the target components only by injecting the theoretical air amount. Therefore, in consideration of the tendency of the component change in the actual operation, it must be added to or subtracted from the theoretical air amount. If it is increased, the air blowing amount should be decreased, and if the concentration keeps decreasing, the air blowing amount should be reduced to a constant concentration. In other words, a correction factor for applying theoretical air volume to actual operation should be obtained.

The correction coefficient is calculated by analyzing the trend of the CO analysis value. In order to obtain a correction coefficient from the analyzed CO value, the component analysis value closest to the present point in time is expressed as CO _n , and before that, CO _n-1 and CO _n-2 , CO _n-3 ....., the correction factor is calculated by the following process.

CO _n -CO _n-1 = K _f1 , CO _n-1 -CO _n-2 = K _f2 , CO _n-2 -CO _n-3 = K _f3 , .....

Thus, K _fn = (K _f1 + K _f2 + K _f3 + .....) / n, that is, K _fn = K _fx = CO _{n-x + 1} -CO _nx where x is a positive integer.

As a result, the correction coefficient K _ff can be expressed as Equation 2.

K _ff = (1.0-K _fn ) ----- (Equation 2)

Since the component of the circulating gas is the theoretical air amount calculated based on the current analysis value, the calculated air amount is not applied to the air intake line 3a where air is blown. Will be.

In other words, it analyzes the CO concentration according to the result of operating according to the initial value, calculates the value exceeded from the standard CO concentration, and considers the correction coefficient by operation on the theoretical air amount that can incinerate the concentration of CO exceeding the initial value. It is. As a result, the amount of air to be blown is calculated by equation (3).

_{_F} = A + A A _{_b _need ff} * K * K _fp ----- (Equation 3)

Here, A _{_f} is a target air intake amount, the amount _{_b} A conventional air intake, A _{_need} the theoretical air quantity, K _ff is a correction factor, K _fp is a plant characteristic coefficient.

K _fp taking into account the characteristics of each facility in Equation 3 is a factor for compensating for the differences of each facility, and is determined by an operational test, so that it can be applied to several facilities in the same way. The application of the present invention was analyzed to apply 0.4 to 0.7 as a result of the operation test of Pohang Iron & Steel Gwangyang Phase 1 CDQ, but generally 0.5 can be obtained.

On the other hand, the air blowing amount increases in proportion to the flow rate of the circulating gas, but it is sometimes difficult to blow a sufficient amount of air by the air blowing amount regulating valve 3b. In order to improve this, by additionally blowing the necessary air through the pre-cooling chamber (2) and the air blowing line (2a) described above to reduce the H ₂ and CO early.

The additional air blowing can be calculated, for example, by multiplying 0.5% of the difference between the current amount of circulating gas and the maximum amount of circulating gas according to the equipment specifications, where 0.5% is the experience value according to the performance of the operation. Can be.

In addition, as described above, nitrogen is blown in order to prevent the boiler from being damaged due to excessive rise of the boiler inlet temperature due to incineration of the powdered coke due to the blowing of air, and the nitrogen blowing amount is a target temperature and a present value. Compare and lower it below the target value.

The nitrogen injection amount calculates the total calorie value of the circulating gas and the total calorie value at the target temperature and the present total calorific value, and calculates the amount of nitrogen which can be cooled by dilution by Equation 4.

V _N = [(T _p -T _t ) * Circ _{_flow} ] / (T _p -T _N ) ----- (Equation 4)

Where V _N is the nitrogen injection amount, T _p is the current temperature, T _t is the target temperature, T _N is the nitrogen temperature, and Circ _{_flow} is the circulating gas flow rate.

As described above, control of the circulating gas component is performed according to the following steps based on a theoretical air amount, a correction coefficient, and a target air blowing amount calculation formula for adjusting the component of the circulating gas.

First, the air blowing amount in a coke dry fire extinguishing system is measured using the air blowing amount flowmeter 3c, and the circulating gas component analyzer 9 analyzes the circulating gas component.

Subsequently, the calculation control unit 20 calculates a theoretical air amount, a correction coefficient, and a target air blowing amount for adjusting the circulating gas component based on the above-described equations 1 to 3.

Then, the air blowing amount is controlled through the air blowing amount control valve 3b so that the air as much as the target air blowing amount is blown according to the calculated value.

In addition, when the temperature of the inlet side of the boiler 6 of the coke dry fire extinguishing system measured by the boiler inlet thermometer 6a is excessively raised above the critical temperature, the nitrogen for cooling is blown in through the nitrogen inlet line 6b. You can also perform the steps.

For example, the operation status of the circulating gas component of the coke dry fire extinguishing system according to the present invention is a circulating gas flow rate of 230,000 Nm ³ / Hr, an initial air blowing amount of 20,000 Nm ³ / Hr, a measured CO concentration of 6%, When the target CO concentration is 4%, the H ₂ concentration is 2%, and the management standard is 1%, the required air blowing amount is calculated as follows.

CO _{_flow} = 230,000 * ( _0.06-0.04 ) = 4,600 Nm ³ / Hr

H _{2_flow} = 230,000 * (0.02-0.01) = 2,300 Nm ³ / Hr

O _{2_need} = 4,600 * 0.5 + 2,300 * 0.5 = 3,420 Nm ³ / Hr

A _{_need} = 3,420 / 0.21 = 16,285 Nm ³ / Hr

If the correction coefficient K _ff is 0.5 and the facility characteristic coefficient K _fp is 0.5, then the target air intake A _f = 20,000 + (16,258 * 0.5 * 0.5) = 24,064.5 Nm ³ / Hr.

As described above, according to the system and method for controlling the circulating gas component of the coke dry fire extinguishing system according to the present invention, it is possible to automatically control the amount of air blown to control the circulating gas component in the coke dry fire extinguishing facility according to the operating conditions. As a result, it is not necessary to continuously monitor the component analysis value of the circulating gas, thereby reducing the work load and having the effect of enabling stable facility operation with the target component.

In addition, it is possible to determine the exact amount of air blown to prevent the incineration of coke in addition to H ₂ and CO gas in the circulating gas.

Claims (8)

In the coke dry fire extinguishing system for extinguishing and cooling high temperature coke discharged from the coke oven, The theoretical air amount for adjusting the circulating gas component is calculated from the circulating gas component inside the coke dry fire extinguishing facility and the air blowing amount information blown into the coke dry fire extinguishing facility, and a correction factor is calculated through an analysis of the performance of the air blowing amount. Computing control unit for determining the target air blowing amount; Circulating gas component control system of the coke dry fire extinguishing equipment comprising a. The method of claim 1, The circulating gas component control system of the coke dry fire extinguishing system, characterized in that the nitrogen inlet pipe for injecting cooling nitrogen into the boiler inlet of the coke dry fire extinguishing facility. In the method of controlling the circulating gas component of a coke dry fire extinguishing system for extinguishing and cooling high temperature coke discharged from a coke oven, Measuring air intake in the coke dry fire extinguishing system and analyzing a circulating gas component; Calculating a theoretical air amount for adjusting the circulating gas component, calculating a correction coefficient by analyzing the performance of the blowing air amount, and calculating a target air blowing amount; And controlling an air intake amount such that the air is blown as much as the target air intake amount. The method of claim 3, The theoretical air amount is calculated by the formula 1, characterized in that the circulating gas component control method of the coke dry fire extinguishing equipment. A _{_need} = (CO _{_flow} * 0.5 + H _{2_flow} * 0.5) / 0.21 ----- (Equation 1) (In the formula, A is _{_need} theoretical amount of air, CO _{_flow} necessary circulation amount of CO gas, H _{2_flow} to incineration of H ₂ is the amount of the circulation gas to be incinerated.) The method of claim 3, The correction coefficient is a circulating gas component control method of the coke dry fire extinguishing system characterized in that it is calculated by the formula (2). K _ff = (1.0-K _fn ) ----- (Equation 2) Where K _ff is the correction factor and K _fn is Where K _fx = CO _{n-x + 1} -CO _nx and CO _n is the closest circulating gas component analysis at the present time.) The method of claim 3, The target air blowing amount is calculated by the formula 3, characterized in that the method for controlling the circulating gas component of the coke dry fire extinguishing equipment. _{_F} = A + A A _{_b _need ff} * K * K _fp ----- (Equation 3) (In the formula, A _{_f} is a target air intake amount, the amount _{_b} A conventional air intake, A _{_need} the theoretical air quantity, K _ff is a correction factor, K _fp is a plant characteristic coefficient.) The method of claim 3, And injecting cooling nitrogen when the boiler inlet side temperature of the coke dry fire extinguishing system is greater than or equal to a critical temperature. The method of claim 7, wherein The nitrogen injection amount is calculated by the equation 4, characterized in that the circulating gas component control method of the coke dry fire extinguishing equipment. V _N = [(T _p -T _t ) * Circ _{_flow} ] / (T _p -T _N ) ----- (Equation 4) Where V _N is the nitrogen injection, T _p is the current temperature, T _t is the target temperature, T _N is the nitrogen temperature, and Circ _{_flow} is the circulating gas flow.