JPS63148001A - Operation control method of fluidized bed boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for operating a fluidized bed boiler for fluidized combustion of solid fuel such as coal.

[Prior Art] A fluidized bed boiler that crushes solid fuel in a crusher and performs fluidized combustion can burn coal more efficiently than other types of coal-fired boilers such as a moving bed type. FIG. 2 is a system diagram showing the configuration of a conventional fluidized bed boiler, in which coal is charged into a hopper 10 from a coal bunker, silo, etc., and is sent from a screw feeder 12 through an aerostat valve 14 to a dryer 16 where it is dried. Ru. Next, it is put into the crusher 18 and crushed, and then distributed to a plurality of pipes 38 by a distribution device (splitter) 20, and the fluidized combustion boiler main body 2
The airflow is conveyed to 2.

The fluidized combustion boiler main body 22 includes a boiler furnace body 24, and the inside of this furnace body 24 is divided into upper and lower sections by an air distribution plate 26. Primary air for combustion is introduced into the lower chamber 28 from a pipe 30. A fluidized bed is formed in the fluidized combustion chamber 32 above the dispersion plate 26, combustion heat is transferred to the water pipe 34, and the combustion exhaust gas is discharged from the exhaust port 36 at the top of the furnace body 24 along with some dust. taken out. In order to supply fuel particles to the fluidized bed combustion chamber 32 above the distribution plate 26, the combustion chamber 32 and the splitter 20 are connected by a plurality of air flow conveying pipes 38.

In a fluidized bed boiler configured in this way, it is necessary to manage the supply of a predetermined amount of coal to the fluidized bed boiler main body, but drying and crushing equipment such as a crushing device and a drying device upstream of the splitter 20 must be controlled. Alternatively, blockage may occur in receiving equipment such as a hopper on the upstream side, or in the piping 38 on the downstream side of the splitter 20, and the amount of coal supplied to the fluidized bed boiler body 22 may deviate from the set amount.

Conventionally, such a phenomenon in which the amount of coal supplied deviates from a set value is detected by checking the combustion temperature of the fluidized bed boiler main body 22, 02 in the combustion exhaust gas, or the like.

[Problems to be Solved by the Invention] However, when detecting a blockage phenomenon in the fuel supply system based on the combustion temperature in the fluidized bed boiler body, the 02 concentration in the combustion exhaust gas, etc., it is difficult to detect the combustion temperature, There was a problem in that it took a relatively long time for fluctuations in the 02 concentration etc. to appear, resulting in delayed blockage detection. Further, this also caused the problem that it was difficult to perform accurate boiler control.

[Means for Solving the Problems] The fluidized bed boiler operation management method of the present invention includes a distribution device for receiving solid fuel such as crushed coal and distributing it to a plurality of air flow conveying branch pipes. In a fluidized bed boiler, the pressure difference between the pressure inside the distribution device and the pressure inside the fluidized combustion chamber is detected, and by detecting that this pressure difference is lower than a predetermined range, the amount of solid fuel introduced into the distribution device can be adjusted. This is to detect that the amount is below a set amount, that is, that a blockage has occurred at the inlet portion of the distribution device or a portion upstream thereof.

Furthermore, the fluidized bed boiler operation management method of the present invention detects that the branch pipe is clogged by detecting that this differential pressure is higher than a predetermined range.

[Operation] In a fluidized bed boiler, solid fuel such as coal that has been dried and crushed in a drying facility or a crushing facility is supplied from a distribution device to the fluidized bed boiler main body by air flow through a branch pipe. However, if a blockage occurs at the inlet of the distribution device, or at the upstream receiving facility, drying and crushing facility, etc., the solid fuel will not be transported by airflow within the branch pipe. Then, the differential pressure between the distribution device and the fluidized combustion chamber becomes significantly smaller. In the present invention, by detecting that this differential pressure becomes lower than a predetermined range, a blockage phenomenon at the introduction section of the distribution device or on the upstream side thereof is detected.

In addition, if a blockage occurs in this branch pipe,
The differential pressure between the distribution device and the fluidized combustion chamber increases accordingly. Therefore, by detecting that this differential pressure has become higher than a predetermined range, it is possible to detect a blockage phenomenon in the branch pipe.

Since such a change in differential pressure occurs almost simultaneously with the occurrence of a blockage phenomenon, according to the present invention, the occurrence of a blockage can be quickly detected.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a system diagram showing the configuration of an apparatus suitable for carrying out the present invention. Reference numeral 40 is receiving equipment, which includes a hopper for receiving solid fuel such as coal (in this example, coal);
A feeding device such as a screw feeder for taking out coal from this hopper is provided (none of these are shown). Reference numeral 42 denotes coal drying and crushing equipment, which includes a drying device and a crushing device (not shown) such as a crusher.

The reference numeral 20 is the aforementioned splitter, and the dry crushing equipment 42
The crushed coal is distributed and supplied to the branch pipe 38. This branch pipe 38 is connected to the fluidized combustion chamber 32 of the fluidized combustion furnace main body 22.
The coal particles are transported by air flow. Note that the configuration of the fluidized bed boiler main body 22 is the same as that shown in FIG. 2 above, so
Identical parts are given the same reference numerals and their explanations will be omitted.

Therefore, in this embodiment, a differential pressure gauge 44 is used to detect the differential pressure between the pressure inside the splitter 20 and the inside of the flow combustion chamber 32.
are installed and connected to the splitter 20 and the fluidized combustion chamber 32 via pipes 46 and 48, respectively. Further, the detection signal of this differential pressure gauge 44 is sent to the determination circuit 5 via a signal line 50.
It is output to 2.

In the fluidized bed boiler configured in this manner, if a blockage occurs in the receiving equipment 40 or the drying and crushing equipment 42, the supply of coal from the splitter 20 to the fluidized combustion chamber 32 via the pipe 38 is stopped.

Then, the pressure inside the splitter 20 and the flow combustion chamber 32
The differential pressure within becomes less than the predetermined range. For example, if this is expressed as a calculated value, it will be as follows. Now cross-sectional area 21.
Assuming that air is flowing at a flow rate of 17 m/see in a pipe with a diameter of 98 crn" (nominal diameter 50 A) and a length of 10 m, the pressure drop ΔP is as follows: ΔP = (4fpu2L) / (2gD) = (4X
O,005x 1.27x 172x 10)/ (2
X 9.8 X 52.9X 1O-3) = 70.8m
mAq. On the other hand, if coal particles are flowing in this pipe with a solid-air ratio m = 2, the pressure loss due to friction is ΔPm = (
1+am)xΔP (where a is a constant determined by the physical properties of the transported object, the inner diameter of the transport pipe, the transport air velocity, etc.). Therefore, when coal particles stop flowing in this pipe, this Δ
Since Pm disappears, the differential pressure becomes only ΔP, which decreases significantly.

Therefore, in the apparatus shown in FIG. 1, if a blockage occurs at the inlet of the splitter 20 or a portion upstream thereof, coal particles will no longer flow within the branch pipe 38, and the flow between the inside of the splitter 20 and the fluidized combustion chamber 32 will be reduced. The differential pressure between the inside and outside becomes lower than the predetermined range.

Then, in response to the differential pressure of the differential pressure gauge 44 being lower than a predetermined range, the determination circuit 52 sends an alarm signal, etc. to indicate that a blockage has occurred at the splitter inlet portion or a portion upstream thereof. It is output as .

Furthermore, if a blockage occurs in the branch pipe 38, the splitter 20
The pressure difference between the internal pressure and the internal pressure of the fluidized combustion chamber 32 will increase. For example, if there are 15 pipes 38 and one of them becomes clogged, the pressure difference between the pressure inside the splitter 20 and the pressure inside the flow combustion chamber 32 will be (15/14) 2
That is, it becomes about 1.15 times. (The differential pressure up until then was 70.8
mmAq, it becomes 81.3 mmAq). In this way, when at least one pipe is clogged, a large differential pressure rise occurs, so by detecting this differential pressure rise, blockage in the pipe 38 can be detected. (In this case, the determination circuit 52
When it is determined that the detected differential pressure of No. 4 is higher than a predetermined range, an alarm signal indicating a blockage in the pipe 38 is output. As described above, according to the present invention, a blockage in the inlet portion of the splitter 20, the upstream side thereof, or the branch pipe 38 can be detected.

Since the variation in the differential pressure of the differential pressure gauge 44 occurs immediately when the blockage occurs, according to the present invention, it is possible to quickly detect the blockage phenomenon.

Note that various types of conventionally used equipment can be used as the receiving equipment and drying and crushing equipment in the apparatus of the above embodiment. Furthermore, the configuration of the fluidized bed boiler main body 22 can be various configurations that have been conventionally used.

Further, as the determination circuit 52, for example, a known microcomputer or the like can be used.

[Effects of the Invention] As described above, according to the present invention, a blockage phenomenon in the fuel supply system to the fluidized bed boiler main body can be detected extremely quickly.

Therefore, according to the present invention, it is also possible to accurately control a fluidized bed boiler.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the configuration of an apparatus suitable for carrying out the present invention, and FIG. 2 is a system diagram showing the configuration of a conventional fluidized bed boiler. 10...Hopper, 18...Crusher,
20... Splitter, 22... Fluidized bed boiler main body, 32... Fluidized combustion chamber, 38... Branch piping, 44
...Differential pressure gauge. Patent applicant: Ube Industries Co., Ltd. Agent: Patent attorney Tsuyoshi Shigeno Figure 2

Claims (2)

[Claims] (1) In a fluidized bed boiler that includes a distribution device that receives crushed solid fuel and distributes it to a plurality of branch pipes for airflow conveyance, and a fluidized bed boiler main body to which these branch pipes are connected to a fluidized combustion chamber, By detecting the pressure difference between the pressure in the distribution device and the pressure in the fluidized combustion chamber, and by detecting that this pressure difference is lower than a predetermined range, the amount of crushed solid fuel introduced into the distribution device is lower than the set amount. A fluidized bed boiler operation management method that detects that (2) In a fluidized bed boiler having a distribution device that receives crushed solid fuel and distributes it to a plurality of branch pipes for airflow conveyance, and a fluidized bed boiler main body to which these branch pipes are connected to a fluidized combustion chamber, The flow control system detects the pressure difference between the pressure in the distribution device and the pressure in the flow combustion chamber, and detects that the branch pipe is clogged by detecting that the pressure difference is higher than a predetermined range. How to manage the operation of a floor boiler.