JP3264152B2 - Air blowing method in coke dry fire extinguishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air blowing method for preventing a temperature of circulating gas flowing into a waste heat boiler of a coke dry fire extinguishing system from decreasing.

[0002]

2. Description of the Related Art In recent years, for the purpose of energy saving and environmental measures, red-hot coke is charged into a cooling tower, cooled circulating gas is blown from a lower portion of the cooling tower, the red-hot coke is cooled, and heat exchange with red-hot coke is performed. A so-called coke dry fire extinguishing system (CDQ) that conducts circulating gas, which has become hot due to heat, to a waste heat boiler to generate steam and recover heat.
Has been put to practical use.

[0003] The amount of steam generated from the CDQ is directly affected by the charging amount and charging temperature of the red hot coke to be cooled. For example, when the amount and temperature of the red hot coke discharged from the coke oven and charged into the cooling tower temporarily increases and decreases due to the kiln discharge, the temperature of the circulating gas changes and the steam generation amount of the boiler decreases. Increase or decrease. As a result, it is difficult to determine the amount of steam generated by the boiler or to control the amount of steam to be swallowed to the maximum amount.

In order to solve this problem, air is blown into the exhausted circulating gas at the outlet of the cooling tower to burn a part of the combustible components of the circulating gas and maintain the temperature of the circulating gas at a constant value. An air blowing amount control method has been proposed. One such method is disclosed in Japanese Patent Application Laid-Open No. 54-10302. This is a method in which a component of a low-temperature circulating gas blown into the bottom of a cooling tower is measured, and air and N ₂ gas are added in accordance with a change value of a standard gas component, particularly a change value of a combustible gas component.

[0005]

However, in the method of blowing air at the outlet of the cooling tower, the circulating gas whose temperature has risen due to the combustion of the combustible gas flows through the duct between the outlet of the cooling tower and the boiler inlet. The heat of the circulating gas dissipates from the duct wall into the atmosphere. For this reason, there is a problem that the heat obtained by the combustion of the combustible gas cannot be sufficiently utilized for generating steam. The present invention
It is an object of the present invention to provide a method capable of fully utilizing the heat obtained by blowing air.

[0006]

The present invention achieves the above object by the following method.

A first method is a method of blowing air into a circulating gas in order to increase the amount of steam generated from a waste heat boiler. This is a method in which air is blown into three locations.

The second method is the same as the first method, except that the temperature sensor is provided at the outlet of the flue and at the inlet of the waste heat boiler.
Control the air flow upstream of the dust removal plate based on the measured value of
The gas temperature at the upstream blowing point of the dust removal plate by 7
In this method, the temperature is set to 40 ° C. or higher .

A third method is a method according to the first method, wherein a flame detector is provided at the inlet of the waste heat boiler, and the amount of air blown downstream of the dust removing plate is controlled by detecting the flame.

The operation of the above method is as follows. First method: If the amount of air to be blown is divided into three locations, ie, the cooling tower flue section, the upstream position and the downstream position of the dust removing plate, and blown, the flue outlet can be reduced compared to the conventional method of blowing only at the cooling tower flue outlet. Since the length of the flow path from the other two blowing positions to the boiler is short, the amount of heat dissipation from the duct wall is reduced. Therefore, the amount of steam generated in the boiler can be increased by the reduced amount of heat dissipation.

Second method: H which is a main component of the circulating gas
_In order to burn ₂ , the temperature at the air
It is necessary to be higher than ° C.

Third method: If the air blowing amount at the downstream position of the dust removing plate is too large, the flame hits the evaporator tube of the boiler, and the evaporator tube is deteriorated and its life is shortened. When a flame is detected by a flame detector arranged at the boiler inlet, if the amount of air blown at a position downstream of the dust removing plate is reduced, it is possible to prevent the flame from hitting the evaporating tube and to prevent a life deterioration. .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing one embodiment of the present invention. In FIG. 1, low-temperature circulating gas sucked by a circulation fan 1 is blown from a lower portion of a cooling chamber 2. The low-temperature circulating gas exchanges heat with the red hot coke 3 charged in the cooling chamber 2 to become a high-temperature circulating gas and enters the duct 5 via the flue 4. A dust plate 6 is provided in the duct 5, and the fine dust coke in the circulating gas is removed by the dust plate 6. The circulating gas from which the fine coke has been removed generates steam in the waste heat boiler 7, and is cooled to become a low-temperature circulating gas. The low-temperature circulating gas exiting the waste heat boiler 7 is dust-removed by the dust collector 8, and is sucked into the circulation fan 1 again.

In order to carry out the present invention, three air blowing pipes are provided inside the duct 5 of the coke dry fire extinguishing system as described above.
It is provided separately for each location. These air blowing pipes include an air blowing pipe 11 at the flue outlet position, an air blowing pipe 12 at a position upstream of the dust removing plate 6 between the flue outlet and the dust removing plate, and a dust removing plate 6 between the dust removing plate 6 and the waste heat boiler inlet. Is an air blow pipe 13 at a downstream position of the air blow pipe.

The four air blowing pipes 11 at the flue outlet position are dispersedly mounted at four locations on the inner circumference of the duct so as to be blown uniformly over the entire cross section. In addition, the air blowing pipe 1 at the upstream position
As in the embodiment shown in FIG. 4, one is located on the upstream side in the flow direction of the circulating gas (12a) and one is located on the downstream side in the turbulent flow area TF of the circulating gas generated before the dust removing plate 6 (12b). ) Install and install a total of four air blowing pipes at two locations corresponding to the duct width direction. Further, one (13a) of the air blowing pipes 13 at the downstream position is installed in a turbulent flow area TF generated at the rear part of the dust removing plate 6, and a total of two air blowing pipes are attached together with the corresponding positions in the width direction of the duct. In addition, in FIG. 4, FL is a gas streamline in a laminar flow region.

The position of the turbulent flow region TF is determined by model calculation or wind tunnel experiment to determine the position where the turbulence region TF is generated, and the mounting position of the duct for the actual machine is determined. In the turbulent flow region, the circulating gas is agitated by the turbulent flow, and the concentration of the flammable gas, such as H ₂ gas, is uniform, so if the air is blown into this turbulent flow region, the combustion flame of the flammable gas becomes stable There is an effect of doing.

The blowing air produced by the air blowing blower 14 is supplied to the air blowing pipe 11 through a flow meter 16 and a flow control valve 17 connected to a pipe branched from the discharge pipe 15.
In addition, a flow meter 18 and a flow control valve 19 connected to a pipe branched from the discharge pipe 15 connect the air blow pipe 12 to the air blow pipe 12.
Further, the air is supplied to the air blowing pipe 13 through a flow meter 20 and a flow control valve 21 connected to a pipe branched from the discharge pipe 15.

In order to measure the temperature of the circulating gas flowing near the air blowing pipe 11, a thermometer 2 is provided near the air blowing pipe 11.
2 is provided, and a thermometer 23 is provided for measuring the temperature of the circulating gas flowing into the waste heat boiler.

A flame detector 24 is provided near the inlet of the waste heat boiler for detecting that the flame generated by the air blow from the air blow pipe 13 reaches the inlet of the waste heat boiler.
Further, a gas component detector 25 of the circulating gas and a circulating gas flow meter 26 are provided downstream of the circulating fan 1.

The method of the present invention is carried out by the above-described apparatus as follows. The air blowing amount of the air blowing pipes 11 to 13 in which the air blowing amount obtained based on the flammable component of the circulating gas and the empirical value is distributed to the calculator 30 at a fixed ratio is calculated by the calculator 3
0 is input in advance. The flow control valves 17, 19 and 21 of the respective air blowing pipes control the flow in accordance with a command from the computer 30, and a set amount of air is blown from the respective air blowing pipes 11, 12 and 13. On the other hand, the measured value T ₂₂ Contact and T ₂₃ of the thermometer 22 and 23 are sent to the arithmetic unit 30, the circulation gas temperature T ₁₂ and T ₁₃ in the air blowing tubes 12 and 13 are calculated based on these measurements .

[0021] When the temperature T ₁₂ of the air blowing tube 12 is lower than 740 ℃, temperature, for example, saw a margin to 740 ℃, 80
0 air blowing amount necessary to only raise the circulating gas temperature temperature difference ℃ and T ₁₂ is calculated. An opening increment of the flow control valve corresponding to the air blowing amount is commanded to the flow control valves 17 and 19, and the blowing amounts of the air blowing pipes 11 and 12 are controlled.

Further, the computer 30 calculates the measured value T23 of the boiler inlet thermometer ₂₃ and the boiler inlet allowable temperature of 100.
The temperature difference from 0 ° C. is calculated, and the air blowing amount required to raise or lower the circulating gas temperature by this temperature difference is calculated. An increase or decrease in the opening degree of the flow control valve 21 corresponding to the air blowing amount is commanded, and the blowing amount of the air blowing pipe 13 is controlled. The operation is performed so that the boiler inlet temperature becomes 990 ° C. in consideration of the fluctuation of the gas temperature.

When a flame is detected by the flame detector 24 at the boiler inlet, a command to decrease the preset opening amount is issued from the computer 30 to the flow control valve 21 and the air blow pipe 13 is blown. The amount is controlled.

Further, since the volume of the circulating gas is increased by blowing air, the increased amount is recovered as fuel gas downstream of the circulating fan 1. For this reason, the gas component value detected by the gas component detector 25 is transmitted to the calculator 30, and when the combustible component value (CO, H ₂ , CH _4, etc.) deviates from the reference component value, or when the oxygen concentration Is too high, the amount of increase or decrease in air blowing is calculated and the total air blowing is controlled.

The arithmetic unit 30 calculates the gas calories of the circulating gas based on the combustible component values (CO, H ₂ , CH _4, etc.) of the circulating gas which are input, and calculates the calories as the recovered gas. Is too low (for example, 200 kcal / Nm ³ or less) or unburned O ₂
If it is not suitable as a recovered gas (for example, the oxygen concentration is 2% or more), it is necessary to reduce the amount of blown air. Conversely, the calorie of the recovered gas is too high (for example, 1000
(kal / Nm ³ or more), it is necessary to increase the amount of blown air. In such a case, taking into account the detection cycle (1 minute) of the gas component detector 25 and its measurement error, etc., and avoiding a sudden change in the amount of blown air, the air blown amount is calculated by Equation 1 (for example, 1 minute). Calculated each time).

[0026]

(Equation 1)

The maximum air injection amount and the minimum air injection amount (Nm ³ / h) depend on the amount of coke discharged from the lower part of the cooling tower (t / h) and the target recovered steam amount (t / h). ), The amount of circulating gas and the charging coke temperature (° C), etc., are determined by the equipment conditions and operating conditions. Therefore, the total amount of air to be blown is the amount between the maximum air blow and the minimum air blow. Adjusted.

[0028]

FIG. 2 shows a conventional method in which air is blown at two locations upstream of the flue portion and the dust removal plate, and a blow at three locations by blowing air downstream of the dust removal plate at two locations of the conventional method. 4 is a graph showing changes in the amount of generated steam, the amount of air blown, and the temperature of circulating gas in the case of the method of the present invention. September 2 that implemented the present invention
From day 0, the amount of steam generated is 106.1 T / hr → 109.7 T / hr
And the temperature difference between the flue outlet temperature and the boiler inlet temperature has been reduced by about half from 56 ° C to 25 ° C. The reason for this is that the temperature drop during this period is reduced by blowing air downstream of the dust removal plate. FIG. 3 is a diagram showing the correlation between the amount of heat input to CDQ and the amount of generated steam for the two-point injection and the embodiment of the present invention. These figures show that a 3 T / H increase in steam volume can be obtained by the method of the present invention.

[0029]

According to the present invention, the amount of generated steam can be increased by dividing the air blowing into three portions. Further, according to the second method, the combustible components can be more effectively burned. Further, according to the third method, it is possible to further prevent deterioration of the evaporator tube due to the flame.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of an air blowing method of the present invention.

FIG. 2 is a graph showing changes in the amount of air blown, the amount of generated steam, and the gas temperature in the conventional method and the embodiment of the method of the present invention.

FIG. 3 is a correlation diagram between a heat input amount and a steam generation amount in the conventional method and the method of the present invention.

FIG. 4 is an explanatory view of a mounting position of an air blowing pipe according to the present invention.

[Explanation of symbols]

Reference Signs List 4 Flue 5 Duct 6 Dust remover 7 Waste heat boiler 11 Flue outlet air blow-in pipe 12, 12a, 12b, 12c, 12d Dust remover upstream air blow-in pipe 13, 13a, 13b Dust remover downstream air blow-in pipe 17 Flue outlet flow control valve 19 Dust plate upstream flow control valve 21 Dust plate downstream flow control valve 22 Flue outlet thermometer 23 Boiler inlet thermometer 24 Flame detector

Continuation of the front page (72) Inventor Kenichi Nemoto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (56) References JP-A-63-110281 (JP, A) Jpn. (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C10B 39/02 C10B 41/00

Claims (3)

(57) [Claims] 1. A method for blowing air into a circulating gas in order to increase the amount of steam generated from a waste heat boiler, wherein the amount of air to be blown is reduced at three positions: an outlet of a cooling tower, an upstream position and a downstream position of a dust removing plate. An air blowing method for a coke dry-type fire extinguishing facility, wherein air is blown separately. 2. A set to the inlet of the flues outlet and the waste heat boiler
Based on the temperature measured by the beam temperature sensor.
By controlling the inflow air amount,
2. The method for blowing air into a coke dry fire extinguishing system according to claim 1 , wherein the gas temperature at the place is 740 ° C. or higher . 3. The method for blowing air in a coke dry fire extinguishing system according to claim 1, wherein a flame detector is provided at an inlet of the waste heat boiler, and the amount of air blown downstream of the dust removing plate is controlled by detecting the flame.