JP5166320B2 - CO concentration control method in coke dry fire extinguishing equipment - Google Patents

Description

  In the coke dry fire extinguishing equipment that cools red hot coke taken out from a coke oven with an inert circulating gas, in order to suppress a sudden increase in the CO concentration in the circulating gas when the red hot coke is charged, The present invention relates to a method for adjusting the amount of air blown at the time of charging red hot coke, in which the amount of air blown is adjusted before charging and charging is completed to control the CO concentration below a predetermined amount.

  Coke dry fire extinguishing equipment is used to cool red hot coke taken out from the coke oven. The red hot coke is charged into the pre-chamber from the upper part of the fire extinguishing tower of the coke dry-type fire extinguishing equipment, and is cooled in contact with the inert circulating gas blown from below while descending the cooling chamber.

  Coke dry fire extinguishing equipment is widely known, and a fire extinguisher is composed of a pre-chamber, a cooling room, and a slowing flue between the pre-chamber and the cooling room.

  A cooling gas blowing device and a coke discharge port for blowing a cooling gas made of an inert gas such as nitrogen are provided in the lower part of the cooling chamber. The red hot coke conveyed from the coke oven is charged into the pre-chamber from the charging device, cooled while coming into contact with the cooling gas blown from the cooling gas blowing device while descending the cooling chamber, from the coke discharge port. Discharged.

  The high-temperature cooling gas discharged from the fire extinguisher is introduced into the boiler and heat exchanged. The cooling gas discharged from the boiler is introduced into the heat exchanger by the circulation fan, sent to the cooling gas blowing device, blown into the cooling chamber, and circulated.

  In the operation of the coke dry fire extinguishing equipment, red hot coke is charged from the top of the pre-chamber (several times per hour), and the atmosphere in the pre-chamber is generated when red hot coke is charged. Due to the combustible gas (CO) and the CO brought in from the charged coke, the CO concentration of the circulating gas rapidly increases. However, if the operation is continued with the CO concentration still increased, the specific heat of the circulating gas is lowered, and the amount of sensible heat recovered in the subsequent boiler is reduced. Therefore, it is important to reduce the CO concentration. Therefore, the CO concentration is lowered by blowing air into the circulating gas upstream of the boiler to burn the CO.

  As a gas concentration control method, Patent Document 1 discloses that a combustible gas (CO) and an oxygen component in a circulating gas are always kept at a minimum, and a sensible heat recovery amount is maximized so as to maximize a sensible heat recovery amount. Feedback control using a PID control method that compensates for the deviation between the flow rate setting value and the actual value using a bypass air amount controller and the amount of air blown from the air inlet, and feedforward control based on the coke discharge amount and gas concentration results Is disclosed.

JP 2006-183058 A

  However, the technique of Patent Document 1 does not particularly take into consideration that the CO concentration suddenly increases after charging the red hot coke. Therefore, if the CO concentration rapidly increases after the coke charging, the CO concentration is reduced. The current situation is that the operator makes manual adjustments to reduce this. The details will be described with reference to FIG.

  FIG. 7 is a graph showing the effect of air blowing on the CO concentration and the pre-chamber pressure when charging conventional red hot coke. The CO concentration is a concentration measured on the outlet side of the heat exchanger.

  As shown in FIG. 7, since the CO concentration increases for a while after charging the coke, the amount of air blown from the air blowing port provided between the sloping flue and the boiler is increased by the operation of the operator. However, due to the increase in CO brought in by the red hot coke immediately after charging the red hot coke and intrusion air from the charging inlet, the control for the increase in the CO concentration cannot catch up, and the CO concentration increases.

  As described above, it is very difficult for the operator to adjust the flow rate of air blown from the air blowing port so as to obtain a stable low CO concentration. For this reason, after the coke is charged, the CO concentration in the circulating gas increases and the specific heat of the circulating gas decreases, resulting in a decrease in the amount of recovered sensible heat (steam) in the boiler installed subsequently. Was.

Therefore, the present invention provides a CO concentration control method for a coke dry fire extinguishing facility that can suppress a rapid increase in CO concentration when the red coke is charged into the coke dry fire extinguishing facility.

The invention according to claim 1 is a method in which red hot coke is heat-exchanged with a cooling gas composed of an inert gas in a fire extinguisher of a coke dry-type fire extinguishing equipment, and the high-temperature cooling gas discharged from the fire extinguisher is 7000 to 700 in a normal cooling operation. In the operation method of the coke dry fire extinguishing equipment, in which CO combustion air is blown at an air flow rate of 10000 Nm ³ / h , introduced into the boiler, heat is recovered, and the cooling gas cooled and discharged by the boiler is circulated to the fire extinguishing tower. ,
The flow rate of air being blown at charging begins before the normal cooling operation to extinguish tower red hot coke, blow the 10~95Nm 3 / ^h the amount of air required to CO combustion to increase after the coke charged per second blowing continuously increased in air flow increase rate during the loading completion from continuing charging initiation is characterized by blowing increased air flow at charging start time

  The present invention blows CO combustion air into the high-temperature cooling gas discharged from the fire extinguishing tower prior to charging the red hot coke into the fire extinguishing tower in a predetermined increase amount, and then continues charging from the start of charging to the end of charging. In the meantime, by blowing in the increased air flow rate at the start of charging, it is possible to suppress an increase in CO concentration during charging of red hot coke.

It is the schematic which shows an example of the coke dry fire extinguishing equipment applied in this invention. It is a graph which shows the influence which the increase rate of the blowing air flow rate for 1 second exerts on CO concentration and a pre-chamber pressure in this invention. It is a graph which shows the influence which it has on the CO density | concentration and pre chamber pressure in case the blowing air flow rate increase rate is 100 Nm < ³ > / h. It is a graph which shows the influence which acts on CO density | concentration and a pre chamber pressure in case a blowing air flow rate increase rate is 7 Nm < ³ > / h. It is a graph which shows the influence which it has on the CO density | concentration and prechamber pressure in case the blowing air flow rate increase rate is 10-95 Nm < ³ > / h. It is the schematic which shows another example of the coke dry fire extinguishing equipment applied in this invention. It is a graph which shows the influence which the air blowing at the time of the conventional red hot coke charging has on the CO concentration and the pre-chamber pressure.

  The CO concentration control method and control device for the coke dry fire extinguishing equipment of the present invention will be described with reference to examples.

  FIG. 1 is a schematic view showing an example of a coke dry fire extinguishing equipment to which the present invention is applied.

  In FIG. 1, the coke dry fire extinguishing equipment includes a pre-chamber 3 into which red hot coke is charged from a charging device 2 at the upper part of the fire extinguishing tower 1, and a cooling chamber 4 that is disposed in the lower part and cools the descending red hot coke. It is configured. Between the pre-chamber 3 and the cooling chamber 4, an annular slowing flue 5 is provided for extracting the cooling gas that has been subjected to heat exchange and has reached a high temperature, and the slowing flue 5 is connected to the flue 6.

  A cooling gas blowing device 7 and a coke discharging device 8 for blowing a cooling gas made of an inert gas such as nitrogen are provided in the inverted conical portion at the bottom of the cooling chamber 4. A cooling gas is supplied from the heat exchanger 9 to the cooling gas blowing device 7.

  The red hot coke conveyed from the coke oven by the fire extinguisher 1 is charged into the pre-chamber 3 from the charging device 2 and contacts the cooling gas blown out from the cooling gas blowing device 7 while descending the cooling chamber 4. Then, it is cooled and discharged from the coke discharging device 8.

  On the other hand, the cooling gas that has been brought into contact with the red hot coke and heat-exchanged to a high temperature is dust-removed in the flue 6 and then introduced into the boiler 10 to be heat-exchanged and cooled. The cooling gas discharged from the boiler 10 is removed by a dust catcher 11 connected to the gas outlet side of the boiler 10, introduced into the heat exchanger 9 by the circulation fan 12, and sent to the cooling gas blowing device 7. Then, it is blown into the cooling chamber 4 and circulated.

  In the operation of the coke dry fire extinguishing equipment, when the CO concentration is increased, the specific heat of the circulating gas is decreased, and the sensible heat recovery amount in the subsequent boiler is decreased. The air is blown into the cooling gas that has been heat-exchanged from the fire-extinguishing tower 1 and heated to a high temperature upstream from the air blowing port 13 to burn the CO, thereby reducing the CO concentration. The flow rate of the blown air is adjusted by a flow rate adjusting valve that is the flow rate adjusting means 14. The flow rate adjusting means 14 may be controlled and adjusted as shown in FIG. 6 instead of the flow rate adjustment valve.

  In the present invention, as described below, in order to suppress a sudden increase in CO concentration when charging red hot coke, before starting the charging of red hot coke into the fire extinguishing tower, and then from the start to the end of charging of red hot coke. The flow rate of the blown air is adjusted, and after the charging is completed, the flow rate of the blown air is adjusted by feedback control according to the CO concentration.

  FIG. 2 is a graph showing the influence of the increase rate of the blown air flow rate per second on the CO concentration and the pre-chamber pressure in the present invention.

In FIG. 2, the air flow rate (about 7000 to about 10,000 Nm ³ / h) blown in the normal cooling operation from 150 seconds to 15 seconds before the start of charging of the red hot coke into the fire extinguisher is 10 Nm ³ per second. The air is increased at a rate in the range of / h (dashed line) to 95 Nm ³ / h (two-dot chain line).

  When the pre-chamber lid is opened and the charging of red hot coke is started, ± 30% of the air flow rate Q blown at the start of charging of red hot coke, that is, 0.7 × Q to 1.3 × Q Blow at an air flow rate in the range of. Thereby, the increase in CO concentration by the increase in CO concentration at the time of red hot coke charging can be suppressed.

Regarding the red hot coke charging start time, the following knowledge was obtained as a result of testing and analysis with various changes in the start time of blowing, with the rate of increase of the blowing air flow rate (range of 10 to 95 Nm ³ / h per second) being a constant value. Obtained.

If the air increase time before starting the red hot coke charging is made too long (that is, the increase start time is too early than 150 seconds before), the total blown air flow rate becomes too high, and O ₂ in the blown air causes the inside of the chamber to Since coke burns and CO is produced by a reduction reaction, the CO concentration cannot be controlled low. It was also found that if the air increase time is too short (starting time of increase is too late than 15 seconds before), the amount of O ₂ required for CO combustion is insufficient and the CO concentration cannot be controlled.

  From the above results, it has been found that it is appropriate to start increasing the blowing air flow rate before starting the charging of red hot coke from 150 seconds to 15 seconds in advance.

  Next, the test was carried out by changing the increasing rate of the blowing air flow rate for 1 second in an appropriate time (within a range of 150 seconds to 15 seconds before) before starting the charging of the red hot coke.

FIGS. 3 to 5 are graphs showing the influence of the increase rate of the blown air flow rate for one second on the CO concentration and the pre-chamber pressure. FIG. 3 is a graph showing the case where the blown air flow rate increase rate is 100 Nm ³ / h, and FIG. When the air flow rate increase rate is 7 Nm ³ / h, FIG. 5 is a graph showing the case where the blown air flow rate increase rate is 10 to 95 Nm ³ / h.

As shown in FIG. 3, when the amount of air increased by 100 Nm ³ / h per second, pressure fluctuation occurred in the chamber, and the amount of circulating gas fluctuated as the pressure balance of the entire CDQ facility changed. The amount of steam recovered in the boiler is fluctuating.

On the other hand, as shown in FIG. 4, with an increase in the amount of air of 7 Nm ³ / h per second, the increase in CO brought in by coke brought in by the subsequent process of red hot coke charging and CO generated by intrusion air from the charging inlet Air becomes insufficient and the CO concentration cannot be reduced.

As shown in FIG. 5, as a result of testing with various air flow rate increasing speeds within the range of the blowing air flow rate increasing rate shown in FIGS. 3 and 4, stable CO 2 at 10 to 95 Nm ³ / h per second. Concentration and pre-chamber pressure.

From the start to the end of the charging of the red hot coke, 0.7 × Q to the air flow rate Q which is increased by 10 to 95 Nm ³ / h per second until the start of the charging of the red hot coke. Blow with an air flow rate in the range of 1.3 × Q. When it exceeds 1.3 × Q, when the coke is charged, hot gas blows out of the system, contaminates the environment, and is not preferable for safety. In addition, when it is less than 0.7 × Q, the pressure in the pre-chamber is reduced, and outside air (atmosphere) enters from outside the system, thereby burning the internal coke and generating CO by a reduction reaction. The CO concentration in the circulating gas cannot be lowered. Therefore, it was found that the proper value is 0.7 × Q to 1.3 × Q.

1: Fire extinguisher 2: Charger 3: Prechamber (PC)
4: Cooling chamber 5: Slowing flue 6: Flue 7: Cooling gas blowing device 8: Coke discharging device 9: Heat exchanger 10: Boiler 11: Dust catcher 12: Circulating fan 13: Air blowing port 14: Flow rate adjusting means (Flow adjustment valve, blower)

Claims (1)

Heat exchange of red hot coke with a cooling gas composed of inert gas in the fire extinguisher of the coke dry fire extinguishing equipment, and an air flow rate of 7000 to 10000 Nm ³ / h during normal cooling operation to the high temperature cooling gas discharged from the fire extinguisher In the method of operating the coke dry fire extinguishing equipment, in which CO combustion air is blown in, introduced into the boiler to recover heat, and the cooling gas cooled and discharged by the boiler is circulated to the fire extinguishing tower.
The flow rate of air being blown at charging begins before the normal cooling operation to extinguish tower red hot coke, blow the 10~95Nm 3 / ^h the amount of air required to CO combustion to increase after the coke charged per second CO concentration in coke dry-type fire extinguishing equipment characterized by continuously increasing the air flow rate at a rate of increase in air flow rate, and then blowing in the increased air flow rate at the start of charging from the start of charging to the end of charging. Control method.

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