JPH0756026B2 - Method for preventing rupture of boiler tube in coke dry cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention detects abnormalities in a heat transfer tube called a boiler tube of a dry cooling device for cooling a cauterizing coke extruded from a coke oven, and breaks the heat transfer tube. It is related to the method for preventing.

[Prior Art] As an apparatus for extinguishing and cooling the burning coke extruded from a coke oven, in recent years, for example, from the viewpoint of energy saving
The dry cooling device shown in Japanese Patent Laid-Open No. 56-45860 is being used.

The structure of this dry cooling device will be described below with reference to FIG.

Burning coke extruded from a coke oven is charged into the cooling tower 1 of the dry cooling device through a charging port 2 provided at an upper portion of the cooling tower 1, and a low temperature gas is supplied from a cooling gas blowing port 4 provided at a lower portion of the cooling tower 1. Circulating gas is blown in.

On the way of descending the cooling tower 1, the ablation coke is sequentially cooled by the circulating gas rising from the lower part of the cooling tower 1 to the body part, and is discharged from the lower part of the cooling tower 1.

On the other hand, as described above, the circulating gas blown from the cooling gas blowing port 4 of the cooling tower 1 absorbs heat from the cauterizing coke while rising in the cooling tower 1 and reaches a high temperature of about 900 to 1000 ° C. 5 and flows into the boiler 11 through a duct 10 having a dust catcher 9.

The boiler 11 cools the high-temperature circulating gas to 160 to 180 ° C., and the cyclone 12, the blower 13, and the cooler 14 in the next stage are sequentially passed through the cooling gas inlet 4 of the cooling tower 1 as a low-temperature circulating gas. It will blow again.

[Problems to be Solved by the Invention] In the boiler 11, heat transfer tube groups SH _{1 to} SH ₅ through which cooling water flows are arranged in a high-temperature circulating gas flow passage 15, and particularly the heat transfer tube group.
In order to improve the heat recovery efficiency, the pipes 3 are densely arranged in SH ₄ and SH ₅ , and fins 6 are provided on the outer periphery of the pipe 3 as shown in FIG. 2 in order to expand the heat transfer area. Provided (hereinafter, this pipe is referred to as a finned heat transfer pipe).

On the other hand, the small coke and the powder coke in the cooling tower 1 fly from the sloping flue 5 along with the hot circulating gas.

The flying small coke and powder coke damage the conduits of the heat transfer tube groups SH _{1 to} SH ₅ and puncture them to leak cooling water. Immediately after this pipe breaks, the cooling of the cauterizing coke in the cooling tower 1 must be stopped and the broken pipe must be repaired, which requires a great deal of time and labor. In particular, in a coke oven operating with one dry cooling device, the burning coke could not be cooled during that time, which was a serious problem.

The present invention causes the above problems by predicting the breakage of the pipes of the heat transfer tube groups SH _{1 to} SH _{5 while} the dry cooling device is operating, and removing the cause of the breakage based on the prediction. The challenge is to carry out stable operations without doing so.

[Means for Solving the Problem] The present inventors have found that when the pipes of the heat transfer tube groups SH _{1 to} SH _{5 in} the boiler 11 puncture, the pressure loss in the boiler 11 increases. , The present invention is based on this,
The characteristic means 1 is that a caulking coke is charged from the upper part and a coke cooled from the lower part is cut out, and a boiler tube for circulating a cooling medium is arranged in the hot gas passage, and the hot gas passage is provided. A boiler for recovering the heat of the high-temperature circulating gas flowing through the boiler, and the high-temperature circulating gas derived from the body of the cooling tower is supplied to the boiler, and the low-temperature circulating gas that has been deprived of heat by the boiler and flows out is the cooling tower. A coke dry cooling device having a circulating gas passage circulated from the lower part into the cooling tower, wherein a pressure measuring device is provided at the inlet and outlet of the boiler, and the circulating gas pressure value of the boiler inlet and outlet parts measured by the both pressure measuring devices. The pressure difference is calculated from the above, and a flow meter for measuring the circulating gas flow rate is installed at the outlet side of the boiler, and the pressure is calculated from the circulating gas flow rate value measured by the flow meter and the preset reference circulating gas flow rate value A correction coefficient is obtained, the calculated pressure difference is corrected by the pressure correction coefficient to obtain a corrected pressure difference, and when the corrected pressure difference becomes equal to or greater than a preset reference pressure difference, the coke dry cooling device is operated. The method is a method for preventing breakage of a boiler tube of a coke dry cooling device by stopping and removing coke adhering and depositing in the boiler.

In addition to the pressure measuring device at the inlet and outlet of the boiler, means 2 is provided with a plurality of pressure measuring devices in the circulating gas flow direction in the boiler, and the circulating gas pressure value at each position measured by each pressure measuring device is used to determine each position. The pressure difference between the two is calculated, each pressure difference is corrected by the pressure correction coefficient to obtain a corrected pressure difference, and when the corrected pressure difference becomes equal to or greater than a preset reference pressure difference,
This is a method for preventing hole breakage of a boiler tube of a coke dry cooling device by stopping the operation of the coke dry cooling device and removing the coke that has adhered and accumulated between the pressure measurement positions where the pressure difference exceeds the reference pressure.

[Operation] The operation of the present invention will be described with reference to FIGS. 1 to 4.

The cause of the conduit of the heat transfer tube group SH ₁ ~SH ₅ is Yabuana the present inventors have in the boiler, as shown in Figure 3 while going to various investigations, the heat transfer tube group SH ₁ ~SH ₅ Boiler when pipeline breaks
The pressure loss inside 11 rises sharply.

When repairing Yabuana conduits of the heat transfer tube group SH ₁ ~SH _5, small lump coke deposited deposited to the conduit of the heat transfer tube group SH ₁ ~SH _5, initially it was commissioned Remove the coke breeze We have found that the pressure loss inside the boiler 11 is low.

As a result of further studying this, the heat transfer tube groups SH _{1 to} SH ₃ in the upper area of the boiler have pipe lines arranged at intervals of 40 mm to 50 mm, while in the lower area of the boiler, The pipes 3 of the heat transfer pipe groups SH ₄ and SH ₅ are arranged at intervals of 10 mm to 20 mm, and the fins 6 are attached to the periphery of the pipes 3 as described above, and the fins 6 are seen in a plan view. When they are turned on, they are in an overlapping state as shown in FIG.

For this reason, the small coke that has flowed in from the cooling tower 1 along with the circulating gas at a high temperature causes the small heat transfer tube groups SH ₄ and SH _{5 in the} lower part of the boiler 11 to flow.
Between the fins 6 of the finned heat transfer tube 3 or between the fins 6 and the heat transfer tube 3 to cause clogging, and the coke dust that has flowed in along with the high-temperature circulating gas adheres to this as well. accumulate.

However, for some reason, between the fins 6, or between the fins 6
When the small coke sandwiched between the heat transfer tube 3 and the heat transfer tube 3 escapes, or when the deposition height of the amount of powder coke becomes too high, the adhered deposition layer of the small coke and powder coke is broken, and the boiler 11 It flows down with the circulating gas flowing inside.

A large amount of the flowing powder coke and the small coke collide with the finned heat transfer tube 3 below, which is similar to the case where a large amount of the powder coke and the small coke were locally blown to the heat transfer tube 3. It was found that the heat transfer tube 3 and the fins 6 were successively worn away to make them thinner, and finally the heat transfer tube 3 reached a rupture hole.

From this, in order for the heat transfer tube 3 with fins in the lower part of the boiler 11 to reach a rupture hole, as shown in FIG. 4, the boiler is proportional to the amount of lump coke and powder coke deposited and accumulated on the heat transfer tube 3.
We have found that the pressure loss in 11 increases.

That is, as in the present invention, a large number of pressure measuring devices 20 to 23 are arranged in the inlet / outlet of the boiler 11, preferably in the height direction of the boiler 11.
The pressure difference between the predetermined positions in the boiler 11 is calculated from the pressure difference of the circulating gas measured by the pressure measuring devices 20 to 23, that is, the pressure loss is calculated, and the small pressure coke and the powder coke are adhered by the calculated pressure difference. Estimating the amount of deposit, and when this estimated amount of adhered deposit exceeds a predetermined value, the supply of circulating gas to the boiler 11 is stopped, and the small coke and powder coke that have adhered and accumulated are removed, so that the heat transfer tube of the boiler 11 The purpose of the invention is to prevent wall thinning or puncture of each pipeline of the groups SH _{1 to} SH ₅ .

[Example] An example of the present invention will be described below with reference to FIG.

In the figure, SH _{1 to} SH ₅ are heat transfer tube groups provided in the boiler 11, SH ₄ and SH ₅ are heat transfer tube groups with fins, and SH _{1 to} SH ₃ are simple heat transfer tubes without fins etc. Tube) group.

20 to 23 are pressure gauges provided in the boiler 11,
Is installed on the inlet side of the boiler 11 and measures its pressure P ₁ . The pressure gauge 23 is provided on the outlet side of the boiler 11 and measures the pressure P ₄ thereof. The pressure gauge 21 is provided between the heat transfer tube group SH ₃ and the finned heat transfer tube group SH ₄ , and measures the pressure P ₂ thereof. The pressure gauge 22 is provided between the finned heat transfer tube group SH ₄ and the finned heat transfer tube group SH ₅ , and measures the pressure P ₃ thereof. Reference numeral 24 denotes a circulating gas flow meter provided on the outlet side of the boiler 11, which measures the circulating gas flow rate Q passing through the inside of the boiler 11. 25 is the pressure inside the boiler 11 measured by the pressure gauges 20-23
A pressure difference calculation unit that deoxidizes each pressure difference ΔP ₁₁ , ΔP ₂₁ , and ΔP ₃₁ of P _{1 to} P ₄ , 26 is a pressure correction coefficient calculation unit, and when the amount of gas flowing in the boiler 11 is changed, the inside of the boiler 11 is changed. Since the pressure fluctuates, the circulating gas flow rate Q measured by the circulating gas flow meter 24 is compared with the reference gas flow rate Q ₀ from the setter 27, and the correction factors for the pressure differences ΔP ₁₁ , ΔP ₂₁ , and ΔP ₃₁ are compared. Calculate α. 28
Is a pressure correction coefficient calculator 2 for calculating the pressure differences ΔP ₁₁ , ΔP ₂₁ , ΔP ₃₁ between the respective positions in the boiler 11 calculated by the pressure difference calculator 25.
The pressure correction calculation unit that performs correction calculation using the correction coefficient α calculated in 6 and 29 is the correction pressure difference ΔP calculated in the pressure correction calculation unit 28.
₁₂ , ΔP ₂₂ , ΔP ₃₂ is compared with the reference pressure difference ΔP ₀₀ from the setting device 30, and when each correction pressure difference ΔP ₁₂ , ΔP ₂₂ , ΔP ₃₂ becomes larger than the reference pressure difference ΔP ₀₀ , an alarm device It is a comparison unit that outputs an abnormal alarm signal to 31. The alarm device 31 issues an alarm by the abnormal alarm signal from the comparison unit 29.

In other words, when the red hot coke extruded from the coke oven (not shown) is cooled by the dry cooling device, the small lumps and the powder coke flow into the boiler 11 along with the circulating gas and enter the heat transfer tube groups SH _{1 to} SH ₅ . Heat transfer tubes with fins that are sequentially deposited and accumulated
SH ₄ and SH ₅ have a large amount of small lumps and coke powder that adhere and accumulate.

Since the circulating gas in the boiler 11 is sucked by the blower 13 provided on the downstream side of the boiler 11 as in FIG. 5, the pressure of the boiler 11 has a high negative pressure at the bottom.
Negative pressure decreases as it goes to the top.

For this reason, as described above, the small mass in the heat transfer tube group SH _{1 to} SH ₅ , the circulation gas becomes worse as the powder coke adheres and deposits, and the negative pressure measured by the pressure gauges 20 to 23 is small (that is, It becomes the positive pressure direction). For example, heat transfer tubes with fins
When small particles and powder coke start to adhere to SH ₄ , pressure gauges 22,23
The pressure measurement values P ₃ and P ₄ of _{No. 1} change little, but the negative pressures of the pressure measurement values P ₁ and P ₂ of the pressure gauges 20 and 21 gradually decrease.

Thus, the pressure difference ΔP ₂₁ between the pressure gauges 21 and 22 gradually increases. As a result, the corrected pressure difference ΔP ₂₂ after correction in the pressure correction calculation unit 28 increases successively, and when the difference exceeds the reference pressure difference ΔP ₀₀ , the comparison unit 29 issues an abnormal alarm signal and an alarm device 31 issues an alarm.

By the alarm of this alarm device 31, the operator stops the supply of the circulating gas to the boiler 11 and cools the boiler 11.

After the cooling of the boiler 11, the small lumps and the coke of powder adhering to the finned heat transfer tube group SH ₄ are removed, and the operation of the boiler 11 is restarted.

In the present embodiment, the abnormality of the boiler 11 is automatically detected, but the present invention is not limited to this, and the pressure differences ΔP ₁₁ , ΔP ₂₁ , and ΔP ₃₁ calculated by the pressure difference calculation unit 25 can be calculated. The operator may directly monitor and detect the abnormality by this pressure difference.

Alternatively, it is acceptable to set up a pressure gauge 20 23 only, thereby the boiler 11 detects the overall abnormal, the nodules after cooling of the boiler 11, heat transfer tube group SH ₁ ~SH adhering deposition of coke ₅
May be detected by the operator to remove the small lumps and the coke dust that have adhered and accumulated. However, in this case, it takes some time to restart the operation, but this does not pose a serious operational problem.

[Effect] The present invention detects abnormalities before a heat transfer tube in a boiler is damaged and removes small particles and powder coke that cause damage to the heat transfer tube. Since it does not flow out to the outside and no repair is required, it is possible to restart the boiler in a short time, and in particular, a coke oven that cools red hot coke by extinguishing with a single dry cooling device. It is effective in this field, and the effect in this field is enormous.

[Brief description of drawings]

FIG. 1 is a simplified explanatory view of an embodiment of the present invention, and FIG. 2 (a).
(B) is an explanatory view of the heat transfer tube with fins in the boiler, FIG. 3 is a view showing a pressure loss value in the boiler during the operation of the dry cooling device, and FIG. 4 is attached and deposited on the heat transfer tube in the boiler. The figure which shows the relationship between the amount of small coke and powder coke and the pressure loss.
The figure shows a conventional example. 1 ... Cooling tower, 2 ... Input port, 3 ... Pipe line, 4 ... Inlet port, 5 ... Sloping flue, 6 ... Fin, 9 ... Dust catcher, 10 ... Duct, 11 ... Boiler, 12 ... Cyclone, 13 …… Blower 14 …… Cooler, 15 …… Circulating gas flow passage 20〜23 …… Pressure measuring instrument 24 …… Flowmeter, 25 …… Pressure calculation unit 26 …… Pressure correction coefficient calculation unit 27 …… Setting device , 28 …… Pressure difference calculation part 29 …… Comparison part, 30 …… Setting device 31 …… Alarm device, SH …… Heat transfer tube group

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Eto 1 Nishinosu, Oita-shi, Oita Pref. Nippon Steel Co., Ltd. Inside Oita Works (56) Reference JP 60-44582 (JP, A) Sho 63-54032 (JP, U)

Claims (2)

[Claims] 1. A cooling tower in which a cauterizing coke is charged from the upper portion and a coke cooled from the lower portion is cut out, and a boiler tube for circulating a cooling medium in the high temperature gas passage are provided, and the high temperature gas passage is passed through the boiler. A boiler that recovers the heat of the high-temperature circulating gas and a high-temperature circulating gas that is derived from the body of the cooling tower are supplied to the boiler, and the low-temperature circulating gas that has been deprived of heat by the boiler and that has flowed out is cooled from the lower part of the cooling tower. A coke dry cooling device having a circulating gas passage for circulating supply in a tower, wherein a pressure measuring device is provided at the inlet and outlet of the boiler, and a pressure difference from the circulating gas pressure value at the boiler inlet and outlet parts measured by the both pressure measuring devices. Furthermore, a flow meter for measuring the circulating gas flow rate is provided on the outlet side of the boiler, and a pressure correction coefficient is calculated from the circulating gas flow rate value measured by the flow meter and the preset reference circulating gas flow rate value. Therefore, the calculated pressure difference is corrected by the pressure correction coefficient to obtain a corrected pressure difference, and when the corrected pressure difference becomes equal to or larger than a preset reference pressure difference, the operation of the coke dry cooling device is stopped. A method for preventing breakage of a boiler tube of a coke dry cooling device, characterized in that coke deposited and deposited in the boiler is removed. 2. In addition to the pressure measuring device at the inlet and outlet of the boiler,
A plurality of pressure measuring devices are provided in the circulating gas flow direction in the boiler, the pressure difference between the respective positions is calculated from the circulating gas pressure value at each position measured by each pressure measuring device, and each pressure difference is corrected by the pressure correction. When the corrected pressure difference is corrected by a coefficient and the corrected pressure difference becomes equal to or more than a preset reference pressure difference, the operation of the coke dry cooling device is stopped, and the pressure measurement becomes equal to or more than the reference pressure difference. The method for preventing breakage of a boiler tube of a coke dry cooling device according to claim 1, characterized in that coke deposited between the positions is removed.