JPS6246769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soot blower control method, and more particularly to a soot blower control method that allows effective blowing to be performed at an optimal time.

When a boiler equipment is operated, soot, ash, etc. adhere to and accumulate on heat transfer surfaces such as water wall tubes in the furnace, deteriorating the heat exchange performance of the heat transfer surfaces. Therefore, it is necessary to operate the soot blower at an appropriate time to remove soot, ash, etc. that have adhered to and accumulated on the heat transfer surface. The number of soot blowers installed is usually around 50 or more in large boilers for power plants, and around 100 in waste heat boilers. Further, in a boiler device for black liquor recovery of a pulp plant, a large number of soot blowers are used to blow at a frequency of about once every three hours, for example.

Conventionally, when operating a soot blower, a boiler operator constantly measured the exhaust gas temperature and draft of the boiler equipment, and when the exhaust gas temperature or draft rose, the operator judged the timing of blowing based on his experience. For this reason, there are individual differences among operators when making judgments, and if the soot blower is not operated properly, the efficiency of the boiler device will decrease.
In addition, operators must constantly monitor changes in exhaust gas temperature and draft, which results in time constraints and poor work efficiency.

Therefore, all soot blowers are normally operated according to a certain sequence regardless of the degree of dirt on the heat transfer surface. However, with this method, the injection medium (steam, steam,
(Air) is used for cleaning, which wastes the jetting medium. In particular, when steam generated in a boiler device is used as an injection medium, it is necessary to capture the amount of steam that is lost, which requires additional fuel. On the other hand, even though blowing is necessary,
Since the operating time has not yet arrived, more soot may accumulate and solidify, making it difficult to remove during the next blowing. Note that there is also a method in which the operator selects a soot blower corresponding to the heat transfer surface and blows the part that requires blowing even if the predetermined operation time has not arrived.
However, in this method, there is a tendency to excessively blow the portions of the heat transfer surface that are estimated to be heavily contaminated, which contributes to a substantial reduction in boiler efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a soot blower control method that eliminates the above-mentioned drawbacks of the prior art and allows the soot blower to blow in the most effective sequence at the required time.

In order to achieve this object, the present invention provides a boiler system equipped with a plurality of soot blowers corresponding to each heat transfer surface, in which a plurality of measurement points are provided to measure boiler characteristics related to contamination on each heat transfer surface. The boiler characteristic data used to set and determine the heat transfer surface contamination allowable limit for each measurement point and the priority order of soot blower operation are stored in advance in the storage unit of the control device, and the boiler characteristics data at each measurement point are stored in advance in the storage unit of the control device. measure,
The comparison/judgment unit of the control device compares the measured value with the boiler characteristic data to determine whether or not the heat transfer surface has reached the allowable limit for contamination. The soot blower corresponding to the heat transfer surface stops blowing, and the soot blower corresponding to the heat transfer surface whose contamination reaches an allowable limit performs blowing according to the priority order.

Next, embodiments of the present invention will be described with reference to the drawings.
In Fig. 1, 1 is a boiler device, which includes a superheater 2, an evaporator water pipe 3, and an economizer 4 along the flow direction of combustion gas.
A heat exchanger such as the following is installed. The high-temperature combustion gas generated by the combustion of the supplied fuel is heat-recovered while passing through the heat exchanger, and is released from the flue via a dust collector and a chimney (none of which are shown). Ru. In addition, 5 is a steam cylinder, 6 is a water cylinder, and 7 is a screen pipe.

While the combustion gas passes through the heat exchanger, soot, ash, dust, etc. contained in the combustion gas gradually adhere to and accumulate on the heat transfer surface, deteriorating the heat exchange performance. In order to determine whether the heat transfer surface is contaminated with soot or the like, the steam temperature is measured in the superheater 2, and the combustion gas temperature and draft differential pressure are measured in the evaporative water pipe 3 and the economizer 4. That is, the steam inlet temperature of the front superheater 2 is TG ₁ , and the steam outlet temperature of the front superheater 2 and the steam inlet temperature of the rear superheater 2 are
At TG ₂ , the steam outlet temperature of the rear superheater 2 is measured at TG ₃ , respectively. Although not shown, a flow meter is installed in the middle of the steam flow path, and the temperature in the front and rear superheaters 2 is determined by the measured value of this flow meter and the steam temperature difference at each measurement point. The amount of absorption is determined for each.

In addition, the combustion gas inlet side of the evaporative water pipe 3, the intermediate part,
A temperature detector and a draft measuring device are installed on each combustion gas outlet side. The combustion gas temperature at each measurement point is detected as t ₁ (inlet side), t ₂ (middle part), and t ₃ (outlet side), and the draft differential pressure between the inlet side and the middle part is ΔP ₁ , and the draft pressure difference between the middle part and the outlet side is The draft pressure difference of is detected as ΔP ₂ . Further, a temperature detector and a draft measuring device are installed on the combustion gas inlet side, the intermediate portion, and the combustion gas outlet side of the economizer 4, respectively. The combustion gas temperature at each measurement point is t ₄ (inlet side), t ₅ (middle part), t ₆
(exit side), the draft differential pressure between the inlet side and the intermediate portion is detected as ΔP ₄ , and the draft differential pressure between the intermediate portion and the outlet side is detected as ΔP ₅ . Further, the draft pressure difference between the outlet side of the evaporative water pipe 3 and the inlet side of the economizer 4 is detected as ΔP ₃ .

Reference numeral 8 designates a slide-type soot blower for cleaning the heat transfer surface of the heat exchanger; an injection pipe with a nozzle at the tip is inserted into the furnace only during operation, and the injection medium (steam) is supplied while rotating the injection pipe. It has a mechanism to spray it. In the soot blower 8, the heat transfer surface of the front superheater 2 is evaporated by _S1 to _S3 , the heat transfer surface of the rear superheater 2 is evaporated by _S4 to _S6 , and the heat transfer surface of the rear superheater 2 is evaporated by _S7 to _S14 . The heat transfer surface of the water tube 3 and the heat transfer surface of the economizer 4 are respectively cleaned in steps S ₁₅ to _{S 19} . These soot blowers 8 S ₁ to _{S 19} can perform blowing one by one or divided into small groups.

The boiler characteristics described above, such as steam temperature TG ₁ to TG ₃ , combustion gas temperature t ₁ to _{t 6} , and draft differential pressure ΔP ₁ to ΔP ₅ , are detected constantly or periodically at relatively short intervals.
The detection signal is inputted to a control device 9 consisting of a microcomputer or the like as shown in FIG.

The storage unit of this control device 9 contains boiler characteristic data (steam temperature, combustion gas temperature, draft differential pressure, etc.) for determining the allowable limit of contamination of the heat transfer surface for each measurement point, and soot blower operation priority. The ranking is stored in advance. Note that since the boiler characteristic values vary considerably depending on the boiler load, the boiler characteristic data is stored in association with the boiler load. The steam temperatures TG ₁ to _{TG 3} , combustion gas temperatures t ₁ to t ₆ , and draft differential pressures ΔP ₁ to ΔP ₅ measured at each measurement point and input to the control device 9 as described above are as follows:
A comparison/determination section of the control device 9 compares the boiler characteristic data with the boiler characteristic data to determine whether or not the heat transfer surface has reached the contamination allowable limit. This matching judgment is
This is done at each measurement point.

As a result of this judgment, for example, the entire superheater 2, the combustion gas inlet side and the intermediate heat transfer surface of the evaporative water pipe 3 have reached the allowable contamination limit, and the combustion gas outlet side of the evaporative water pipe 3 and the energy saver 4 If it is determined that the entire heat transfer surface of the stove does not reach the allowable fouling limit, blowing is performed on S ₁ to _{S 12} of the stove blower 8.
S ₁₃ to S ₁₉ do not require blowing. Once the soot blower 8 to be used for blowing is determined, the soot blowers are arranged in descending order of priority according to the priority order of soot blower operation stored in the storage section, and the order signal is sent to the soot blower panel board 10. For example, the priority of soot blower operation is determined by determining the draft difference when the combustion gas temperature exceeds the reference value of the boiler characteristic data at one measurement point and the draft differential pressure exceeds the reference value of the boiler characteristic data at the other measurement point. If the soot blower closest to the pressure measurement point is operated preferentially, or if the combustion gas temperature at a certain measurement point extremely exceeds the reference value of the boiler characteristic data, the soot blower near that measurement point is operated with priority. Priority items are determined in detail depending on each condition, such as driving with higher priority. Soot blower panel board 10
issues an operating command to each soot blower 8 in accordance with the order signal from the control device 9 to perform blowing.

Comparison of actual boiler characteristic measurements with boiler characteristic data is carried out constantly or periodically at relatively short intervals, and the first comparison results indicate that the heat transfer surface associated with the measurement point has not reached the allowable fouling limit. too,
If the subsequent measured value exceeds the reference value of boiler characteristic data, blowing is performed in the same manner as described above.

As explained above, according to the present invention, the soot blower can perform the most effective blowing at the required time, and there is no loss of the ejected medium.

[Brief explanation of the drawing]

1 and 2 are a schematic configuration diagram and a system diagram for explaining the soot blower control method according to the present invention. 1... Boiler device, 2... Superheater, 3... Evaporative water pipe, 4... Energy saver, 8, _S1 to _S19 ... Soot blower, 9... Control device, TG ₁ to TG ₃ ... Steam Temperature, t ₁ to _{t 6} ... Combustion gas temperature, ΔP ₁ to ΔP ₅ ... Draft differential pressure.

Claims (1)

[Claims] 1. In a boiler device equipped with multiple soot blowers corresponding to each heat transfer surface, multiple measurement points are set to measure the boiler characteristics related to dirt on each heat transfer surface, and the heat transfer at each measurement point is measured. Boiler characteristic data for determining the permissible limit of surface contamination and the priority order of soot blower operation are stored in advance in the storage unit of the control device, the boiler characteristics are measured at each of the measurement points, and the actual values and the soot blower operation priority are stored in advance. The comparison judgment unit of the control device compares the characteristic data with the heat transfer surface to determine whether the contamination tolerance limit has been reached.
Soot blowers that correspond to heat transfer surfaces whose contamination has not reached the permissible limit stop blowing, and soot blowers that correspond to heat transfer surfaces whose contamination has reached the permissible limit perform blowing according to the priority order described above. A soot blower control method characterized by performing the following steps.