JPH0682002B2 - How to operate the soot blower - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a soot blower operating method, and more particularly to a soot blower operating method for removing soot and ash adhering to a heat transfer tube in a fine powder combustion process heating furnace.

[Prior Art] Conventionally, oil is mainly used as fuel in process heating furnaces used in oil refining and petrochemical plants, but fine powder of solid fuel such as coal, petroleum coke, charcoal, and wood is used to solve energy problems. Development of a heating furnace that uses fuel has been promoted.

FIG. 3 shows the configuration of this type of heating furnace. Fine powder combustion burners c are horizontally provided on a pair of side walls b of the heating furnace a facing each other, and a heat transfer tube e is vertically arranged along a pair of side walls d orthogonal to the side walls b. Then, the fine powder combustion burner c burns the fine powder, and the heat transfer tube e
The process fluid passing therethrough is heated. In order to stably produce a product of a predetermined quality and quantity from the plant, it is necessary to stabilize the outlet temperature of the process fluid heated in the heating furnace a to about ± 2 ° C, and to supply the fuel. An outlet temperature control device (not shown) is provided for varying the amount and controlling the outlet temperature using an auxiliary burner.

In such a heating furnace a, a large amount of soot and ash are generated as the fine powder is burned.
The soot and ash adhere to the surface, and if they are left as they are, the heat transfer efficiency to the process fluid passing through the heat transfer tube e decreases.

Therefore, a plurality of soot blowers f are installed inside the furnace of the heat transfer tubes e, and steam is sprayed from these soot blowers f in the direction of the side wall d to remove soot and ash attached to the surface of the heat transfer tubes e.

At this time, since a large amount of steam is required when attempting to inject steam from a plurality of soot blowers f at the same time, conventionally, a blow cycle in which a plurality of soot blowers f are continuously operated is formed, and this blow cycle is defined. Was repeated in the cycle.

For example, when three soot blowers g, h, i are arranged near the heat transfer tube e as shown in FIG. 4, steam injection is started from the soot blower g at time t _{1 as} shown in FIG. At time t ₂ when the soot and ash attached to the heat transfer tubes e within the effective range j are removed, the injection from the soot blower g is finished and the steam injection from the soot blower h is started this time. Similarly, at time t ₃ , the injection from the soot blower h is terminated and the injection from the soot blower i is performed.
The injection ends at time t ₄ . That is, the heat transfer tubes e within the effective blow range k of the soot blower h at time t ₃ and within the effective blow range l of soot blower i at time t ₄ are cleaned.

[Problems to be Solved by the Invention] By the way, when the soot blower is operated and soot and ash are removed from the heat transfer tube within the effective blowing range of the soot blower, the heat transfer efficiency of that portion is improved, and therefore the process of sending out the heat transfer tube The fluid outlet temperature rises sharply. Therefore, the above-mentioned outlet temperature control device acts to return the outlet temperature to the predetermined value T ₀ , but the reaction speed of this control device is generally slow, and the time when the injection of the soot blower g is ended.
The outlet temperature at t ₂ is higher than the temperature T _{0 at} time t ₁ by ΔT ₁ . Here, if the operation of all soot blowers is stopped, the outlet temperature of the process fluid returns to the predetermined temperature T ₀ for a while due to the action of the outlet temperature control device.

However, as described above, at the time t ₂ , the soot blower g
The injection from the soot blower h is started at the same time when the injection from is finished, and the cleaning within the effective blow range k is performed. Therefore, the outlet temperature of the process fluid will rise further,
At time t ₃ , the temperature becomes higher than the temperature T ₀ by ΔT ₂ . Similarly, at time t ₄ , temperature T ₀ rises by ΔT ₃ .

As described above, conventionally, the outlet temperature of the process fluid fluctuates greatly, and it is difficult to stabilize the outlet temperature.

Therefore, an object of the present invention is to provide a method for operating a soot blower that can solve the above-mentioned problems of the prior art and stabilize the outlet temperature of the process fluid.

[Means for Solving Problems] In order to achieve the above object, the method for operating a sootblower according to the present invention has a heat transfer tube for each pass of a fine powder combustion process heating furnace that heats a process fluid in a multipass heat transfer tube. In the operation method of soot blowers that are arranged along each of the paths, after blowing the first soot blower of each pass in sequence, the second soot blower of each pass is sequentially blown, and so on. The soot blower is blown, and the next soot blower is blown after a predetermined time interval from when each soot blower blows until the outlet temperature of the process fluid stabilizes.

[Operation] As described above, the soot blower of a specific path is not continuously blown, but the soot blowers of each path are sequentially blown one by one, so that the soot and ash attached to the heat transfer tubes of each path are averaged. To be removed.

Further, since the soot blowers are blown after the outlet temperature of the process fluid is stabilized, the rise in the outlet temperature due to the blow is not overlapped and amplified.

That is, the outlet temperature of the process fluid is stabilized.

[Examples] Hereinafter, examples of the present invention will be described based on a pulverized coal combustion process heating furnace according to the accompanying drawings.

FIG. 2 is a conceptual diagram of a pulverized coal combustion process heating furnace to which a soot blower operating method according to an embodiment of the present invention is applied. And heat transfer tubes 2 of the heat transfer tube 1 of paths P ₁ along the furnace side walls and path P ₂ is installed vertically, the sootblower 3,4,5 near the heat transfer tube 1, the sootblower in the vicinity of the heat exchanger tubes 2 6 , 7, 8 are arranged respectively. Further, the heat transfer tubes 1 and 2 join together on the downstream side thereof. In the figure, 13 to 18 indicate the effective blow range of the soot blowers 3 to 8, respectively.

Further, the heating furnace is provided with an outlet temperature control device (not shown) for changing the fuel supply amount and stabilizing the outlet temperature of the process fluid.

Next, the operating method of the present embodiment will be described with reference to the process fluid outlet temperature change diagrams of FIGS. 1 (a) to (c). In addition,
Figure 1 (a) ~ (c) outlet temperature T ₁ of the respective paths P _1,
Is a diagram showing the time variation of the temperature T ₃ after the confluence of the outlet temperature T ₂ and path P ₁ and P ₂ of path P _2.

First, pulverized coal combustion is started in the heating furnace, and passes P ₁ and P ₂
The process fluid is introduced into the heat transfer tubes 1 and 2 to be heated, and the outlet temperatures T ₁ , T ₂ and T ₃ of the process fluid are maintained at the predetermined temperature T ₀ by the outlet temperature control device.

Then, at the time t ₁ , blowing of the soot blower 3 of the path P ₁ is started, and after the time required for removing the soot and the ash adhering to the heat transfer tube 1 within the effective blow range 13 (about 2 minutes) has elapsed. The blow ends at time t ₂ . At this time,
Since the soot and ash are removed, the heat transfer efficiency is improved, and the outlet temperature T ₁ of the path P ₁ becomes higher than the initial temperature T ₀ by ΔT. On the other hand, since the outlet temperature T ₂ of the path P ₂ is kept at the temperature T _0, the variation width of the temperature T ₃ after the confluence with the assumed that equal amount of process fluid is caused to flow into the paths P ₁ and P ₂ Is 1/2
ΔT.

After that, the outlet temperatures T ₁ and T ₃ of the process fluid decrease due to the action of the outlet temperature control device, and return to the temperature T ₀ at time t ₃ .

Further, at the time t ₄ , the soot blower 6 of the path P ₂ is started to be blown at this time, and the blow is ended at the time t ₅ when the soot and ash attached to the heat transfer tube 2 in the blow effective range 16 are removed. At this time, the outlet temperature T ₂ of the path P ₂ is higher than the temperature T ₀ delta
While it increases by T, the outlet temperature T ₁ of the path P ₁ remains at the temperature T ₀ , so the fluctuation range of the temperature T ₃ after merging is still 1/2
ΔT.

After the outlet temperature T ₂ and T ₃ to time t ₆ is returned to the temperature T _0, the path P ₁ and so that each sootblower 4,7,5 and 8 at time t ₇ ~t ₁₀ In the same manner as P Blow ₂ soot blowers alternately. Outlet temperature T ₂ of the outlet temperatures T ₁ or path P ₂ of path P ₁ for each blow of sootblower is varied by [Delta] T, the temperature T ₃ after the confluence varies only 1/2 · [Delta] T.

In this way, the fluctuation range of the temperature T ₃ of the process fluid after merging could be controlled to ± 2 ° C.

Although the two-pass type heating furnace is used in the above embodiment, the present invention is not limited to this, and a heating furnace having more than one or three passes may be used. As the number of passes increases, the temperature fluctuation range after the process fluids merge can be reduced.

Further, the number of soot blowers provided in each path is not limited to three.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects are exhibited.

(1) The soot blower can be blown to remove soot and ash adhering to the heat transfer tube while keeping the outlet temperature of the process fluid stable.

(2) Therefore, the stable operation of the fine powder combustion process heating furnace for a long time becomes possible.

[Brief description of drawings]

FIGS. 1 (a) to 1 (c) are changes in the outlet temperature of a process fluid according to the operation method of a sootblower according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of a pulverized coal combustion process heating furnace to which the embodiment is applied. FIG. 3 is a block diagram of a general fine powder combustion process heating furnace, and FIGS. 4 and 5 are explanatory views showing problems in the conventional case. In the figure, T ₁ is the exit temperature of path P ₁ , T ₂ is the exit temperature of path P ₂ ,
T ₃ is the temperature after merging.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sanzan Tamada 4-21-10 Imagawa, Suginami-ku, Tokyo Idemitsu Ogikubosha No. 605 (56) References JP 62-69014 (JP, A)

Claims (1)

[Claims] 1. A method of operating a soot blower in which a plurality of fine powder combustion process heating furnaces for heating a process fluid in a multi-pass heat transfer tube are arranged along each heat transfer tube, respectively. After sequentially blowing the soot blowers of the above, the second soot blower of each pass is blown in sequence, and so on. All the soot blowers of each pass are blown in the same manner, and after each soot blower blows, the outlet temperature of the above process fluid A method for operating a sootblower, characterized in that the sootblower is blown after a predetermined time interval until it becomes stable.