JPH0241442Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a pulverized fuel burner used in boilers, chemical industrial furnaces, etc. that use pulverized coal, charcoal, coke, rubber, plastic, etc. as fuel. Regarding.

BACKGROUND ART FIG. 2 shows a conventional pulverized fuel burner (hereinafter referred to as PM burner) described in Japanese Unexamined Patent Publication No. 149517/1983. In this figure, reference numeral 1 denotes a mixed flow passage through which a mixed fluid of pulverized fuel and air is conveyed, and this passage 1 is connected to a distributor 2 . The distributor 2 uses centrifugal force to divide the mixed fluid introduced from the mixed flow path 1 into a concentrated pulverized fluid 3 with a high pulverized fuel concentration and a light pulverized fluid 4 with a low pulverized fuel concentration.
It is intended to separate the Therefore, the distributor 2 is connected with a concentrated fine powder flow conveying pipe 5 and a light fine powder flow conveying pipe 6, and the centrifugal force of the mixed fluid causes
What flows into pipe 5 has a high concentration of pulverized fuel,
Conversely, the concentration of pulverized fuel flowing into the pipe 6 becomes low.

The concentrated fine powder flow conveying pipe 5 opens at the center of the concentrated fine powder fuel injection nozzle (hereinafter referred to as CONC nozzle) 7, and the light fine powder flow conveying pipe 6 opens at the center of the light fine powder flow injection nozzle (hereinafter referred to as WEAK nozzle) 8. It opens in the center. Note that 9 is the SGR port and 10 is the auxiliary air compartment.

Problems to be solved by the invention The pulverized fuel burner as described above can maintain extremely stable combustion and reduce
It has been well received because it can reduce NO _x .

However, CONC nozzle 7 in PM burner
The fuel distribution between WEAK nozzle 8 and WEAK nozzle 8 is normally CONC
Since the WEAK nozzle is 20-30 compared to the nozzle 80-70, the burnout length of the PM burner and the maximum heat load of the burner compartment are all CONC.
It is to be determined by nozzle 7. Therefore, the maximum heat load on the burner compartment is limited, which determines the number of PM burner stages required for a certain size boiler furnace cross section.

In this way, for a furnace cross section of a certain size, the maximum allowable heat load per burner compartment is determined, and this determines the required number of CONC nozzle stages, that is, the number of PM burner stages and the number of mills. Therefore, in a normal PM burner, apart from boiler turndown, the number of PM burner stages and the number of mills are selected by the number determined by the above. PM burner has CONC nozzle and
A pair of WEAK nozzles constitutes a set of burners, and the height of the burner compartment is inevitably higher than that of a normal burner.

Means for Solving the Problems In order to solve the above problems, the present invention introduces a mixed fluid of pulverized fuel and air, which is conveyed through a supply pipe, into a distributor and has different concentrations of the mixed state. In a pulverized fuel burner which separates a pulverized fluid and a light pulverized fluid and injects each divided fluid from respective nozzles arranged close to each other, a flow rate distribution baffle is provided in the center of the distributor, Two lines of concentrated fine powder fluid are extracted from both sides, and one line of light fine powder fluid is extracted from the middle part, and this light fine powder fluid is injected from a nozzle for light fine powder fluid, and the nozzle for light fine powder fluid is injected from the nozzle for light fine powder fluid. The two series of concentrated fine powder fluids are separately injected from the nozzles for concentrated fine powder fluids formed on both sides so as to sandwich the two lines.

Function Since two CONC nozzles are combined for one WEAK nozzle, the heat input per CONC nozzle is halved, and the PM burner required from the maximum heat load per burner compartment allowed for a furnace cross section of a certain size is reduced. The number of sets will be reduced.

Embodiment An embodiment of the pulverized fuel burner according to the present invention will be described in detail below with reference to FIG. Note that in FIG. 1, the same parts as in FIG. 2 are given the same reference numerals, so a description of those parts will be omitted.

The mixed flow path 1 through which the mixed fluid of pulverized fuel and air is conveyed includes a distributor 20 having three outlets.
are connected. A flow rate distribution baffle 21 is provided in the center of the distributor 20, and two lines of concentrated fine powder flow conveying pipes 5a and 5b are connected to both sides of the flow distribution baffle 21.
A series of light and fine powder flow conveying pipes 6 is connected to the intermediate portion thereof. And, the light fine powder flow conveyor pipe 6 is WEAK
The concentrated fine powder flow conveying pipes 5a and 5b are connected to and open at the center of the nozzle 8, and are connected to and opened at the center of CONC nozzles 7a and 7b provided on both sides of the WEAK nozzle 8, respectively.

Now, the mixed fluid is introduced into the distributor 20 from the passage 1 and divided into left and right by the flow rate distribution baffle 21, but at this time, the pulverized fuel contained in the mixed fluid is biased outward due to centrifugal force and upwards. transported to. Therefore, the shape of the baffle 21 is made appropriate so that 70 to 80% of the total pulverized fuel is introduced into the concentrated fine powder flow conveying pipes 5a and 5b connected to both sides of the distributor 20, and the remaining 30 to 20% of the total pulverized fuel is introduced. % of the pulverized fuel is introduced into the light pulverized flow conveying pipe 6 connected to the central part. In addition, concentrated fine powder flow conveying pipes 5a, 5b
The outlet opening of the distributor 20 is determined so that the flow rate ratio between the two and the two is approximately 1:1.

As a result, from CONC nozzles 7a and 7b,
The concentrated pulverized fluid is injected in an amount less than the theoretical amount of air necessary for combustion of the volatile matter of the pulverized fuel where the primary air/pulverized fuel ratio is 3 to 4 or less, while from the WEAK nozzle 8,
More than the theoretical volatile combustion air amount of pulverized fuel, and
It is possible to inject a light pulverized fluid containing fixed carbon that is less than the theoretical combustion air amount of pulverized fuel.

Therefore, when the burner of the present invention is placed in a boiler furnace with a certain cross-sectional area, if the maximum allowable heat load per burner compartment is constant, the conventional
Approximately twice as much heat can be input into the PM burner,
The number of PM burner sets and mills can be reduced to about half of conventional ones.

Effects of the invention As detailed above, according to the invention, the concentrated powder fluid is divided into two systems using a distributor, and each system is installed on both sides of the WEAK nozzle.
Since I made it to inject from the CONC nozzle, 1
The heat input per CONC nozzle is halved, and the PM required by the maximum heat load per burner compartment allowed for a certain size furnace cross section.
The number of burner sets is halved compared to the conventional one, and the number of mils can also be halved accordingly.

The final number of burner stages and number of mills will be determined by taking boiler turndown and maintenance into consideration, but overall it is certain that the number of PM burner sets and number of mills will be reduced.

[Brief explanation of drawings]

FIG. 1 is a structural explanatory diagram showing one embodiment of a pulverized fuel burner according to the present invention, and FIG. 2 is a structural explanatory diagram showing a conventional pulverized fuel burner. 1...Mixing flow path, 5a, 5b...Dense fine powder flow conveying pipe, 6...Light fine powder flow conveying pipe, 7a, 7b...
CONC nozzle, 8...WEAK nozzle, 20...
Distributor, 21...Flow rate distribution buffer.

Claims (1)

[Scope of utility model registration request] A mixed fluid of pulverized fuel and air conveyed through a supply pipe is introduced into a distributor and separated into a dense pulverized fluid and a light pulverized fluid with different mixing states, and each divided fluid is placed close to the other. In a pulverized fuel burner that injects fuel from each nozzle,
A flow rate distribution baffle is provided in the center of the distributor, and two lines of concentrated fine powder fluid are extracted from both sides thereof, and one line of light fine powder fluid is extracted from the middle part. A pulverized fuel burner configured to inject from a fluid nozzle and to separately inject the two series of concentrated pulverized fluid from dense pulverized fluid nozzles formed on both sides of the light pulverized fluid nozzle.