JPH07217856A - Soot blow controller - Google Patents

Abstract

PURPOSE:To remove combustion dust effectively by a method wherein lances, arranged at every places in a boiler, are opened and closed intermittently and sequentially upon receiving soot blow command to effect soot blow. CONSTITUTION:Lances A, B, C are installed at every places in the combustion furnace of a steam generating boiler and high-pressure steam is ejected from these lances A, B, C whereby combustion dust is removed. The opening and closing of solenoid valves 10A, 10B, 10C, which supply steam to the lances A, B, C, is controlled by a soot blow control unit. The solenoid valves 10A, 10B, 10C are controlled by the soot blow control unit 11 so as to be opened and closed sequentially with a given time width whereby soot blow, in which high-pressure steam is ejected intermittently and sequentially by the lances A, B, C, is effected. According to this method, combustion dust can be removed effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soot blow control device for a boiler used in paper pulp, steel, petroleum refining, petrochemicals, foods, chemicals and other plants.

[0002]

2. Description of the Related Art Conventionally, in a boiler widely used in industrial fields such as paper pulp, steel, petroleum refining, petrochemicals, foods, chemicals, etc., in order to remove combustion dust accumulated in the furnace, various parts in the furnace are removed. A lance is installed at each lance, and soot is blown out from each lance at high speed to blow out combustion dust.

[0003]

However, in the conventional soot blow control device, when the soot blow is sequentially performed by the lances installed at various places inside the furnace of the boiler, as shown in FIG. 5, a soot blow command is given to each lance from the outside. If it is input, the control is performed so that steam is continuously ejected during the command period, and there is a problem that the effective removal of dust is not sufficient.

By the way, generally, when a pipe facility is newly installed in a food plant or the like, it is effective to wash water by intermittently passing water instead of continuously passing water to wash the inside of the pipe. I try to wash it. Therefore, in sootblowing, effective removal of combustion dust can be expected by intermittently ejecting steam.

The present invention was invented under such consideration, and while the soot blow command is given for each lance,
An object of the present invention is to provide a soot blow control device that effectively removes combustion dust by intermittently opening and closing a lance to perform soot blow.

[0006]

A soot blow control device of the present invention includes lances installed at various places of a boiler,
In response to an external soot blow command, the lances are sequentially opened and closed intermittently to perform soot blow control.

[0007]

In the soot blow control device of the present invention, in response to a soot blow command from the outside, the soot blow control unit sequentially opens and closes the lances at various locations of the boiler to perform soot blow, thereby effectively burning the combustion dust in the boiler furnace. To remove.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a system diagram of a general steam generation boiler,
This steam generating boiler supplies the mixed fuel from the fuel line 1 and the air line 2 to the burner 3, burns this mixed fuel in the combustion furnace 4, and discharges the exhaust gas through the chimney 5.
On the other hand, the water in the water line 6 is passed through a preheater 7 in the combustion furnace 4 to be preheated and then supplied to a steam drum 8, where it is heated by combustion gas to generate steam, and the generated steam is further heated by a superheater. It is configured to take out steam that has been heated to a high temperature by passing through 9.

In such a steam generating boiler, lances A, B, C, ... Are provided at various places in the combustion furnace 4, and high pressure steam is ejected from the lances to remove combustion dust. The solenoid valves 10A, 10B, 10C, ... Supplying steam to the lances A, B, C ,.
As shown in FIG. 3, the soot blow control unit 11 controls opening and closing.

The soot blow control unit 11 includes soot blow control circuits 12 as shown in FIG.
Prepare for each. Each soot blow control circuit 12 is connected in series to the soot blow switches 13, 14, 15 and the soot blow switch 13 arranged in parallel, which are turned on at the same time by a soot blow command from a boiler control device (not shown) composed of a computer. , Cycle T
A timer T1 that turns on / off at 1 and a soot blow switch 14 are connected in series, a delay timer T1A that turns on after T1A time, a timer T2 that turns on / off at a cycle T2, and a soot blow switch 15 are connected in series.
From a delay timer T2A that turns on after 2A time, a timer T3 that turns on / off in a cycle T3, and relay contacts t1, t2, and t3 that are arranged in parallel and are turned on while each of these timers T1, T2, and T3 is on. It is configured. Then, the relay contacts t1, which are arranged in parallel,
The outputs of t2 and t3 are the solenoid valves 10A, 10B, 10C,
It becomes a soot blow operation signal that controls the opening and closing of each.

Next, the operation of the soot blow control device having the above configuration will be described. In the circuit shown in FIG. 2, a boiler control device (not shown) inputs to the soot blow control unit 11 a command for sequentially soot-blowing each of the lances A, B, C, ....

Now, the time width W of soot-blowing the lance A
When the soot blow command is given, the soot blow switches 13, 14, 15 in the soot blow control circuit 12 shown in FIG. And timer T
1 intermittently starts ON / OFF operation in cycle T1,
During the time T1 during which the timer T1 is on, the relay contact t1 is on, the solenoid valve 10A is opened, and high pressure steam is ejected into the combustion furnace 4 through the lance A to remove combustion dust. Then, during the next time T1, when the timer T1 is turned off, the relay contact t1 is turned off, which causes the solenoid valve 10A.
Closes and the ejection of high pressure steam from the lance A stops.

If the timer T1 is turned on again during the next T1 time, high pressure steam is similarly ejected from the lance A to remove the combustion dust, and again during the next T1 time, the timer T1 is restarted.
1 turns off, solenoid valve 10A closes, and lance A of high-pressure steam
Squirt from the plant stops.

The timer T1 is preset to 2
Repeatedly turning on / off a number of times, this time T1A (= 4 ×
T1) delay timer T1A is turned on and timer T
2 is driven, and the timer T2 repeats the on / off operation twice in the cycle T2 shorter than the cycle T1 of the timer T1, thereby turning on / off the relay contact t2 and performing the soot blow twice every time of the cycle T2. After that, the delay timer T2A for the time T2A (= 4 × T1 + 4 × T2) is turned on to drive the timer T3, and the timer T3 has a cycle T shorter than the cycle T2 of the timer T2.
The ON / OFF operation is repeated 4 times in 3 to thereby turn ON / OFF the relay contact t3 to perform soot blow 4 times for each cycle T3, and the soot blow of the lance A is completed.

When the soot blow by the lance A is completed, the soot blows of the lance B, the lance C, ... Are sequentially started in the cycle of the soot blow time W, and in the same manner, intermittent combustion of the soot blow causes combustion dust at various places in the combustion furnace 4. To remove.

Thus, in the soot blow control device of this embodiment, the lances A, B, C, and
By sequentially performing soot blowing which ejects high-pressure steam intermittently, combustion dust can be removed more effectively than in the conventional case where high-pressure vapor is continuously ejected. Further, since the soot is blown intermittently, the temperature drop due to the jetting of steam into the combustion furnace 4 can be suppressed more than in the case of continuous soot blow, and the boiler efficiency can be improved.

The present invention is not limited to the above embodiments, and the type of boiler may be a recovery boiler or other type. Also, the number of lances and the installation location are set to the optimum ones according to the type and size of the boiler, and the intermittent operation time and the number of soot blows can be changed appropriately according to the type and size of the boiler. It can also be set to.

Further, in the above embodiment, the control circuit 12 of the soot blow control unit 11 is constituted by the relay sequence, but this can be realized by software control by the microcomputer.

[0019]

As described above, according to the present invention, in response to the soot blow command from the outside, the soot blow control section sequentially opens and closes the lances at various locations of the boiler to perform soot blow, thereby effectively heating the boiler furnace. The combustion dust inside can be removed.

[Brief description of drawings]

FIG. 1 is a system diagram of a steam generating boiler using a soot blow control device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of an embodiment of the present invention.

FIG. 3 is a circuit diagram showing a soot blow control circuit in the above embodiment.

FIG. 4 is a timing chart of the soot blow operation of the above embodiment.

FIG. 5 is a timing chart of a soot blow operation of a conventional example.

[Explanation of symbols]

 1 Fuel Line 2 Air Line 3 Burner 4 Combustion Furnace 5 Chimney 6 Water Line 7 Preheater 8 Steam Drum 9 Superheater 10A, 10B, ... Solenoid Valve 11 Soot Blow Control Circuit 12 Soot Blow Switch 14 Soot Blow Switch 15 Soot Blow Switch T1 Timer T2 Timer T3 Timer t1 Relay Contact t2 Relay Contact t3 Relay Contact T1A Delay Timer T2A Delay Timer

Claims (1)

[Claims] 1. A soot blow control device comprising: a lance installed at each place of a boiler; and a soot blow control unit for intermittently opening and closing each of the lances in response to a soot blow command from the outside to perform soot blow. .