JP2954334B2 - Burner number control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a boiler burner control device and a circuit for controlling the number of burners, which automatically performs ignition / extinguishing control of a boiler burner under an appropriate fuel pressure. About providing.

[Conventional technology]

The conventional burner number control circuit calculates the appropriate number of burner ignitions corresponding to the boiler load command from the boiler dynamic characteristic data, compares this appropriate number with the actual number of burner ignitions, and calculates only the difference between the two. A burner increase (ignition) command or a decrease (fire extinguishing) command is automatically transmitted at an appropriate timing.

[Problems to be solved by the invention]

In the above prior art, since the burner increase / decrease control is performed only by the boiler load command, for example, in a special boiler operation state such as a sudden load change in a low load zone or a high load zone, the fuel pressure fluctuation width is not increased. In some cases, abnormal combustion such as burner misfire or flame blow-off may occur. Further, there is a danger that a burner increase command is transmitted and a low fuel pressure trip occurs even though the fuel pressure is low.

Further, when the fuel pressure is temporarily reduced to a value equal to or lower than the burner ignition permission setting, the burner may be ignited at the same time.

An object of the present invention is to solve the above-mentioned problems and to provide a preferable burner number control circuit that prevents fluctuations in fuel pressure and prevents simultaneous ignition of burners.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a circuit for setting the number of the boiler burners to be ignited or extinguished by a boiler load command transmitted to a plurality of installed boiler burners; A comparison circuit for comparing the set number of ignitions of the boiler burner; a burner ignition / extinguishing command circuit for transmitting an ignition or fire extinguishing signal to the boiler burner based on the signal compared by the comparison circuit; Provided is a burner number control circuit including a fuel pressure correction circuit that corrects the pressure of fuel supplied to all ignited boiler burners including a boiler burner ignited based on a command signal of a fire extinguishing command circuit within a desired range. I do.

The present invention also provides a circuit for setting the number of boiler burners to be ignited or extinguished by a boiler load command transmitted to a plurality of installed boiler burners, a number of boiler burners for which ignition has been completed, and A comparison circuit for comparing the number of ignitions, a burner ignition / extinguishing command circuit for transmitting an ignition or extinguishing signal to the boiler burner based on a signal compared by the comparison circuit, and a pressure of fuel supplied to the boiler burner being predetermined And a burner ignition prevention circuit for stopping the burner ignition signal transmitted to the burner to be ignited when the burner ignition signal is transmitted at a pressure equal to or lower than the pressure of the burner.

[Action]

The correction circuit based on the fuel pressure absorbs the fuel pressure fluctuation when the burner increases / decreases in the direction of the reference fuel pressure, using the ratio of the appropriate reference fuel pressure corresponding to the number of burners and the actual fuel pressure as an index. Set the correction ratio to. Thus, when the fuel pressure deviates from the reference fuel pressure, the burner increase / decrease command stops the transmission and operates so as to maintain the fuel pressure within an appropriate range.

If the burner ignition permission setting is not exceeded,
Stop sending the burner increase command. As a result, the burner increase (ignition) for each burner ignition / extinguishing control circuit
Prevents sending commands.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a burner number control circuit according to the present invention. In the figure, reference numeral 1 denotes a boiler load command, and 2 denotes the actual number of burners ignited during boiler operation. 3 is the lower limit number of burner ignitions corresponding to the boiler load command given by 1 (see FIG. 3).
F _{I (n)} ) is a function generator for transmitting the upper limit number (F _{D (n) of} FIG. 3 ₎ .
Reference numerals 5 and 6 denote comparators for calculating the difference between the lower limit number and upper limit number of burners transmitted from 3 and 4, respectively, and the actual number of burners ignited.
Reference numeral 21 denotes a fuel pressure correction ratio corresponding to the number of burner ignitions, and a ratio of a reference fuel pressure to an actual fuel pressure for maintaining an optimal combustion state for each number of burners. Given by Reference numerals 22, 23 denote function generators for transmitting correction ratios for burner increase / decrease commands using the fuel pressure correction ratio of 21 as an index, and each correction ratio is indicated by F in FIG.
_{Indicated by I (X)} and FD _(X) . Reference numerals 24 and 25 denote multipliers to which a correction ratio (ratio) using the fuel pressure as an index with respect to the burner increase / decrease direction burner number deviation signal transmitted from the burners 5 and 6, respectively, is added. The correction circuit for maintaining the fuel pressure within an appropriate range is constituted by 21, 22, 23, 24, and 25. 7, 8 is 2 each
By inputting the burner increase / decrease burner number deviation signal taking into account the correction ratio due to the fuel pressure transmitted from 4, 25, it is determined whether the current burner number is to be increased (ignition) or reduced (extinction). A burner increase / decrease command transmission circuit for transmitting an increase / decrease command. Reference numeral 9 denotes a backup fuel pressure setting for transmitting a burner increase command when the fuel pressure continues to increase even when the burner increase command from 7 is not transmitted due to some abnormality, which is called a burner increase setting. , represented by P _I in Figure 4. 10 is indicated by P _D of FIG. 4 in similarly burner reduced set. 19 is shown in FIG. 4 P _P called burner ignition permission setting the fuel pressure value that allows the ignition of the burner. If the fuel pressure is lower than this setting, even if a burner increase command is issued, the increase command is locked by the logical product of 17 so that the subsequent ignition command to each burner is not sent. 15a to 15n are ignition commands for the first to nth burners.
Signals are sent to individual burner ignition / extinguishing control circuits at appropriate timings by interval timers a to 13n. Similarly, reference numerals 16a to 16n denote fire extinguishing commands for the first to n-th burners, and reference numerals 14a to 14n denote interval timers for measuring the timing of issuing the fire extinguishing command.

FIG. 2 shows an example of the prior art. The prior art differs from the embodiment of the present invention shown in FIG. 1 in that a fuel pressure correction circuit constituted by reference numerals 21 to 25 and a circuit in which a burner ignition permission setting of 19 is not provided. Therefore, there is a possibility that the fuel pressure may deviate from an appropriate range when the burner increases or decreases, or that a burner ignition command is simultaneously transmitted when the burner ignition permission setting is not reached.

FIG. 3 is a characteristic curve diagram showing a relationship between the number of burners and the number of burners corresponding to the boiler load command. FI _(n) indicates the lower limit of the number of burners and FD _(n) indicates the upper limit. Here, for example, when the boiler load command is at MW ₂ , the number of burner ignitions is n
If it is ₂ , the first is that n ₂ is within the upper and lower limit number.
Neither the burner increase command nor the burner decrease command is transmitted as determined by 5 and 7 and 6 and 8 in FIG. In addition, if the burner ignition number of cormorants n _3,
6 and 8 determine that the upper limit number FD _(n) is exceeded, and issue a burner decrease command to perform an operation of returning the number of burner ignitions from n ₃ to n ₂ (within the upper and lower limit numbers). If Likewise burner ignition number is a n _1, performs an operation to increase from n ₁ to disseminate the burner increase command to the n ₂ by determination of the 5 and 7.

FIG. 4 is a characteristic curve diagram showing the relationship between the fuel flow rate and the fuel pressure for each burner ignition number. Burner increasing characteristic and reduction characteristics according to the prior art deviations from the optimum Naru reference fuel pressure P _P is large. Burner increasing characteristic and reduction characteristic of the present invention, on the other hand is located near the reference fuel pressure P _P by the action of the fuel pressure correction circuit constituted by a 21 to 25 of FIG. 1.

FIG. 5 is a diagram showing a correction ratio using the fuel pressure as an index. The correction ratio for the burner increase command is given by F _{I (X)} , and the correction ratio for the burner decrease command is given by _{FD (X)} ,
This correction ratio is added by the multipliers 24 and 25 in FIG. 1 to realize the operation in which the fuel pressure is kept within an appropriate range as shown in the burner increase / decrease characteristics of the present invention shown in FIG. it can.

〔The invention's effect〕

According to the present invention, the correction circuit based on the fuel pressure operates to absorb the fuel pressure fluctuation at the time of increasing and decreasing the burner in the reference fuel pressure direction. realizable.

Also, by adding a burner ignition permission setting, if this condition is not satisfied, the burner is increased (ignition) from the burner number control circuit.
The transmission of the command is securely locked, and simultaneous ignition of the burners is prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a burner number control circuit according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a burner number control circuit according to the prior art, and FIG. 3 is a characteristic curve showing the relationship with the number of burner ignitions corresponding to a boiler load command. FIG. 4 is a characteristic curve diagram showing the relationship between the fuel flow rate and the fuel pressure for each burner ignition number, and FIG. 5 is a diagram showing a correction ratio using the fuel pressure as an index. 1 ... Boiler load command, 2 ... Number of burner ignitions, 3,4,2
2,23 Function generator, 7 Burner increase command transmission circuit
8: Burner decrease command transmission circuit, 9: Burner increase setting, 10: Burner decrease setting, 19: Burner ignition permission setting, 21: Fuel pressure correction ratio.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Yoshinori Murakami, Inventor 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Omika Plant of Hitachi, Ltd. (56) References JP-A-2-101317 (JP, A) JP-A-64-63712 (JP, A) JP-A-63-286614 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23N 1/00 F23N 5/00

Claims (2)

(57) [Claims] 1. A circuit for setting the number of boiler burners to be ignited or extinguished by a boiler load command transmitted to a plurality of installed boiler burners, the number of boiler burners for which ignition has been completed, and the set boiler burner ignition A comparison circuit that compares the number with the burner ignition / extinction command circuit that transmits an ignition or fire extinguishing signal to the boiler burner based on the signal compared by the comparison circuit; A burner number control circuit, comprising: a fuel pressure correction circuit that corrects the pressure of fuel supplied to all ignited boiler burners including a ignited boiler burner within a desired range. 2. A circuit for setting the number of boiler burners to be ignited or extinguished by a boiler load command transmitted to a plurality of installed boiler burners, the number of boiler burners for which ignition has been completed, and the set boiler burner ignition A comparison circuit for comparing the number of the fuel cells, a burner ignition / extinguishing command circuit for transmitting an ignition or fire-extinguishing signal to the boiler burner based on a signal compared by the comparison circuit, and a pressure of fuel supplied to the boiler burner being a predetermined pressure. A burner ignition prevention circuit for stopping the burner ignition signal transmitted to the burner to be ignited when the burner ignition signal is transmitted at a pressure equal to or lower than the pressure. .