JP2000046315A - Pulverized coal distributing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the facility cost of a pulverized coal distributing device and to shorten the construction period of the device by making pulverized coal to be surely distributed without using any damper and, at the same time, omitting the troublesome adjusting work incidental to the damper by making the dispersed state of pulverized coal in a particle flow uniform before the flowing body reaches a pulverized coal mixer. SOLUTION: A pulverized coal distributing device is provided with a pulverized coal distributor 31 which branches a pulverized coal flow which is carried by a gas into a plurality of flows and a pulverized coal mixer 32 positioned on the upstream side of the distributor 31 and the mixer 32 is provided with a plurality of stages of elements 36 (a, b, and c) which are arranged perpendicularly to the axis. The elements 36 are constituted by arranging a required number of pulverized coal dispersing bars 37 (a, b, and c) in parallel with each other in the same plane. Consequently, pulverized coal can be distributed evenly by making the dispersed state of the pulverized coal in a particle flow uniform before the flow reaches the distributor 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pulverized coal distribution device provided in a pulverized coal supply line of a facility using pulverized coal as a fuel, such as a pulverized coal-fired boiler using pulverized coal as a fuel.

[0002]

2. Description of the Related Art In general, a boiler has a heating power adjusted according to a load condition, and a pulverized coal-fired boiler has a plurality of burners so that the heating power can be adjusted. Accordingly, the combustion of the burner provided for combustion is restricted. The pulverized coal distribution device is provided with a function of evenly distributing the pulverized coal fed in the pulverized coal supply line to the plurality of burners.

[0003] First, a pulverized coal-fired boiler provided with a pulverized coal distribution device will be briefly described with reference to FIG.

The pulverized coal-fired boiler 1 has a primary supply line 2,
The secondary supply line 3 and the exhaust line 4 are connected, and the downstream end of the exhaust line 4 is connected to a chimney 15.

The primary supply line 2 includes a primary air fan 5, a primary air preheater 6, a pulverized coal mill 7, a pulverized coal distribution device 8, and a primary air fan 5 and a primary air preheater 6 arranged from the upstream side. It mainly comprises a heat receiving section 6a, a pulverized coal mill 7, a primary air duct 9 for sequentially connecting the pulverized coal distribution device 8, and branch ducts 10a, 10b, 10c for connecting the pulverized coal distribution device 8 to a burner (not shown). You.

The secondary supply line 3 includes a secondary air fan 11, a secondary air preheater 12, a secondary air fan 11, a heat receiving portion 12a of the secondary air preheater 12, It is mainly constituted by a secondary air duct 13 that sequentially connects the pulverized coal-fired boilers 1.

The exhaust line 4 includes a primary air preheater 6 and an exhaust fan 14 provided from an upstream side (pulverized coal-fired boiler 1 side), and a heat supply section 6b of the pulverized coal-fired boiler 1 and the primary air preheater 6. , An exhaust fan 16, an exhaust duct 16 that connects the chimney 15, and a bypass duct 17 that bypasses the primary air preheater 6 and is connected to the heat supply section 12 b of the secondary air preheater 12 on the way. .

The primary air passes through the heat receiving section 6a of the primary air preheater 6 through the primary air duct 9 by the primary air fan 5 and the heat supply section 6b of the primary air preheater 6
Heat is exchanged with the exhaust gas passing through the preheater to be preheated. The preheated primary air is introduced into the pulverized coal mill 7 through the primary air duct 9. The pulverized coal mill 7 is for pulverizing coal into fine powder capable of carrying fluid, and the pulverized pulverized coal is mixed with the primary air in the primary air duct 9.
Flows into the pulverized coal distribution device 8 via the pulverized coal distribution device 8, and is distributed by the pulverized coal distribution device 8;
The burners (not shown) are supplied through b and 10c.

The secondary air passes through the heat receiving portion 12a of the secondary air preheater 12 through the secondary air duct 13 by the secondary air fan 11, and the secondary air preheater 1
Heat exchange is performed between the exhaust gas passing through the second heat supply unit 12b and preheating. The preheated secondary air is introduced into the pulverized coal-fired boiler 1 through the secondary air duct 13. The pulverized coal-fired boiler 1 burns pulverized coal supplied from the primary air supply line 2 to generate steam. Exhaust gas generated by the combustion is sucked by the exhaust fan 14 and discharged from the pulverized coal-fired boiler 1 to the exhaust duct 16 and then split, and one of the split flows is preheated through the exhaust duct 16. It passes through the heat supply section 6b of the vessel 6. In the process of passing through the heat supply section 6b of the primary air preheater 6, the exhaust gas supplies heat to the primary air and is cooled to a required temperature. The other side of the branch is the bypass duct 1
The secondary air passes through the heat supply section 12b of the secondary air preheater 12 via the heater 7 and is supplied with heat to the secondary air during the passage, and is cooled to a required temperature. The cooled exhaust gas merges again and is discharged outside through the exhaust duct 16 and the chimney 15.

Next, a conventional pulverized coal distribution device 8 will be described with reference to FIG.

[0011] A funnel-shaped branch body 22a, 22b, 2 is connected to the primary air duct 9 at the downstream end of the hollow body 21.
2c are continuously provided, and downstream ends of the branch cylinders 22a, 22b, 22c are respectively provided with stop valves 23a, 23b, 23c.
Are connected to the branch ducts 10a, 10b, and 10c through the connection.

In the pulverized coal powder fluid flowing into the pulverized coal distribution device 8, the pulverized coal in the fluid is drifted due to centrifugal force or the like. For example, as shown in FIG.
Is bent in an L-shape and connected to the body 21, the pulverized coal in the pulverized fluid is unevenly distributed on the outer peripheral side of the curved portion 25,
The dispersion state of the pulverized coal in the pulverized fluid is not uniform. Therefore, in order to equalize the amount of pulverized coal distributed in the branch cylinders 22a, 22b, 22c, the branch cylinder 22a and the branch cylinder 22
b, and at the boundary between the branch body 22b and the branch body 22c, the dampers 24a and 24b are rotatably provided.
4a, 24b, the branch cylinders 22a, 22b,
The area of the branch to 22c is adjusted.

When the positions of the dampers 24a and 24b are set, the pulverized fluid is actually repeatedly flown to find a position where the pulverized coal in the distributed pulverized fluid becomes uniform. After the position is determined, the dampers 24a and 24b are fixed.

[0014]

As described above, in order to distribute pulverized coal evenly, it is necessary to adjust the dampers 24a and 24b, and the adjustment operation cannot be performed by the pulverized coal distribution device alone. It is troublesome to check the dispersion state of the pulverized coal by actually flowing the pulverized fluid, and it took a lot of time. Further, once set, the dampers 24a and 24b are fixed, so that there is a problem that it is not possible to quickly respond to a change in the operating state or a change in the flow state of the powder fluid.

In view of such circumstances, the present invention makes the dispersion state of the pulverized coal in the pulverized fluid uniform before reaching the branch cylinder, eliminates the need for the damper, and ensures the uniform distribution of the pulverized coal. The purpose of the present invention is to omit troublesome adjustment work associated with the damper, thereby reducing equipment costs and shortening the construction period.

[0016]

SUMMARY OF THE INVENTION The present invention relates to a pulverized coal distributor for branching a pulverized coal powder stream for gas transport into a plurality of streams, and a pulverized coal mixer disposed upstream of the pulverized coal distributor. The pulverized coal mixer has a plurality of elements orthogonal to the axis, the element is related to a pulverized coal distribution device comprising a required number of fine powder dispersion rods arranged in parallel in the same plane, Further, the upper and lower adjacent elements of the fine powder dispersing rod relate to a pulverized coal distribution device in which the fine powder dispersing rod is arranged so as to be orthogonal to the fine powder dispersing rod. On the other hand, the element of the separated stage relates to a pulverized coal distribution device in which the fine powder dispersing rod of the separated stage is parallel to the fine powder dispersing rod and located between the fine powder dispersing rod and the fine powder dispersing rod. Homogenizing the dispersion state of the body before reaching the pulverized coal distributor,
Distribute pulverized coal evenly.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the same components as those shown in FIG. 4 are denoted by the same reference numerals.

The pulverized coal distributor 30 includes a pulverized coal distributor 31.
And a pulverized coal mixer 32 connected to the upstream end of the pulverized coal distributor 31.

The pulverized coal distributor 31 is equivalent to the above-described conventional pulverized coal distribution device 8 in which the dampers 24a and 24b are removed, and a funnel-shaped branch cylinder 33a is provided at the downstream end of the hollow body 34. , 33b, 33c are connected to each other,
The downstream ends of the branch ducts 3a, 33b and 33c are respectively connected to the branch ducts 10 through stop valves 23a, 23b and 23c.
a, 10b, and 10c. The branch cylinder 33
The opening area ratio of a, 33b, 33c is a burner (not shown).
Is set to a predetermined value in accordance with the amount of pulverized coal to be fed to the tank.

The pulverized coal mixer 32 will be described with reference to FIGS.

The pulverized coal mixer 32 has a plurality of elements 36 arranged in a cylindrical frame 35 in a plurality of stages. The elements 36 are orthogonal to the axis of the frame 35. The element 36 has fine powder dispersing rods 37 arranged in parallel at a required pitch in the same plane. The fine powder dispersing rod 37 is, for example, an angle-shaped member having an L-shaped cross section, and is arranged such that the corner ridge of the angle-shaped member is located on the upstream side of the powder flow.

Above the fine powder dispersion rod 37a in the second stage from the bottom,
The element 36b of the lower adjacent stage is a fine powder dispersion rod 37.
b is arranged so as to be orthogonal to the fine powder dispersion rod 37a, and the upper separated element 36c is arranged on the fine powder dispersion rod 37c.
Are arranged in parallel with the fine powder dispersion rod 37a and in the middle between the fine powder dispersion rod 37a and the fine powder dispersion rod 37a.

The operation will be described below. The description of the same components as those in the related art is omitted.

The pulverized coal in the primary air flowing from the pulverized coal mill (not shown) in the primary air duct 9 is
5, due to the action of centrifugal force, the air is unevenly distributed on the outer peripheral side of the curved portion 25, and flows into the fine powder mixer 32 in a state where the concentration of pulverized coal in the primary air on the outer peripheral side of the curved portion 25 is high. I do.

The pulverized coal in the primary air is supplied to each of the fine powder
7 while passing through the element 36. The flow of the powder fluid is diverged by the collision of the powder fluid of the gas transport with the fine powder dispersion rod 37, and the branched flow is deflected laterally with respect to the flow by the slope of the fine powder dispersion rod 37 and dispersed. You. Therefore, the portion where the pulverized coal dispersed concentration is high is dispersed every time when passing through each element 36,
The pulverized coal concentration is made uniform. Furthermore, as the pulverized coal dispersed concentration increases, the amount of pulverized coal colliding with the pulverized coal dispersion rod 37 increases, so that the passage resistance of the portion where the pulverized coal dispersed concentration is high increases, and the passing speed of the pulverized coal is reduced. It is slower than the lower part. Therefore, the amount of pulverized coal passing through each element 36 per unit time is gradually made uniform, and the pulverized coal in the primary air after passing through each element 36 is in a state of being uniformly dispersed.

The primary air in which the pulverized coal is uniformly dispersed flows into the pulverized coal distributor 31, and the pulverized coal in the primary air is proportional to the opening area ratio of the branch cylinders 33a, 33b, 33c. A predetermined amount of pulverized coal is distributed to the branch ducts 10a, 10b, and 10c, and is supplied to the burners (not shown).

In the above-described embodiment, the L-shaped angle-shaped member is used for the pulverized coal dispersion rod 37. However, in the case of a long member, an inclined flat band plate or round bar is used. Is also good.

[0029]

As described above, according to the present invention, even if the pulverized coal dispersed concentration in the primary air is not uniform when flowing into the pulverized coal mixer, it becomes uniform during the passage through the pulverized coal mixer, Primary air uniformly dispersed in the pulverized coal distributor can be supplied.

Therefore, the pulverized coal can be evenly distributed, and a damper for adjusting the dispersion state of the pulverized fluid in the pulverized coal distributor is not required. It has the excellent effect of reducing the time and shortening the construction period.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an element according to the embodiment.

FIG. 3 is a system diagram showing a pulverized coal-fired boiler facility.

FIG. 4 is a schematic explanatory view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 30 pulverized coal distribution device 31 pulverized coal distributor 32 pulverized coal mixer 36 element 37 pulverized dispersion rod

Claims (3)

[Claims] 1. A pulverized coal distributor that branches a gas-conveyed pulverized coal powder stream into a plurality of streams, and a pulverized coal mixer disposed upstream of the pulverized coal distributor. A pulverized coal distributing apparatus characterized in that the vessel has a plurality of elements orthogonal to the axis, and the elements are provided with a required number of fine powder dispersion rods in parallel in the same plane. 2. The pulverized coal distribution apparatus according to claim 1, wherein the upper and lower adjacent elements of the fine powder dispersing rod are arranged such that the fine powder dispersing rod is orthogonal to the fine powder dispersing rod. 3. The fine powder dispersing rod is located at an intermediate element between the fine powder dispersing rod and the fine powder dispersing rod. 1. Pulverized coal distribution device.