JP2020041776A - Distributor of solid/gas two-phase flow - Google Patents

Abstract

To provide a distributor of solid/gas two-phase flow capable of substantially reducing distribution deviation in solid/gas two-phase flow to zero.SOLUTION: A distributor of solid/gas two-phase flow comprises: a main body container 4 having the expanding cylinder and a ceiling plate 3 that closes the opening of the cylinder with a larger diameter; one circular inlet duct 1 for supplying the solid/gas two-phase flow to the main body container; two or more circular outlet ducts 2 for discharging the solid/gas two-phase flow from the inside of the main body container; and the same number of plate members 5 as the number of outlet ducts, in which the same number of circular outlet through holes as the number of outlet ducts on the ceiling plate are arranged such that their centers are located at the positions of the vertices of a regular polygon imaged regarding the center of the ceiling plate as the center of gravity, the outlet ducts are connected so as to communicate with the main container in the exit open hole, and the plate-like members are arranged on the underside of the ceiling board so as to cross the arc between two adjacent vertices on the circumscribed circle of the regular polygon.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas-solid two-phase flow distribution device. More specifically, the present invention is intended to control the supply amount of a mixture of conveying air and solid fuel particles (pulverized coal (pulverized coal) or biomass (wood)) to a burner. It relates to a gas-solid two-phase flow distribution device used.

  Usually, a plurality of burners are installed in a furnace of a coal-fired boiler. A mixture of the conveying air and the pulverized coal is supplied to each of these burners. Various devices have been proposed for distributing a multiphase flow of pulverized coal and conveying air in order to control the amount of a mixture of conveying air and pulverized coal supplied to a burner.

  For example, Patent Literature 1 discloses that a powder obtained by pulverizing an object to be pulverized into a mill body is discharged to the outside by air current transfer from a powder outlet at the top of the mill body divided into a plurality in the circumferential direction. In the configured roller mill structure, a table that rotates in the mill body, a plurality of rollers that roll on the table to pulverize the object to be pulverized, and are disposed upstream of the powder outlet. A rotary classifier, and a rectifying device that partially narrows the cross-sectional area of the flow path is provided in the middle of the flow path of the powder airflow flowing into the rotary classifier and flowing toward the powder outlet. A roller mill structure characterized by the above is disclosed. A movable vane is shown as a rectifier. The movable vane is a plate-shaped damper member that swings (opens and closes) about a vertical rotation axis supported on a side wall (outer peripheral side) of the rotary classifier.

  Patent Document 2 discloses a pulverizing unit for pulverizing solid fuel and fuel pipes for supplying the solid fuel pulverized in the pulverizing unit to a plurality of solid fuel combustion burners after being mixed with a carrier gas to form a mixed fluid. In a fuel distribution device of a solid fuel combustion facility having a distribution unit for distributing, a distribution amount adjusting means is provided for adjusting a distribution amount of the solid fuel independently for each connection portion of the distribution unit and each fuel pipe. A fuel distribution device for a solid fuel combustion facility characterized by the above is disclosed. As a distribution amount adjusting unit, a position in which the cylindrical member can be adjusted by a cylindrical member movable to a connection portion between the fuel distribution portion and each fuel pipe, and a connection portion between the fuel distribution portion and each fuel pipe. It discloses a movable plate member in which the position of the plate member can be adjusted.

  U.S. Pat. No. 5,077,086 discloses an outer casing, an inner casing configured to define a passage between which the flow of gas and particles can flow substantially upwards, and a method for separating coarse particles from the flow. Inclined blades to provide rotational flow to the gas and particle flows as the passage passes from the passage into the inner casing, and multiple outlets to discharge gas and particulates, rotation of gas and particulate flows Entrains the mixture of coarse and fine particles, including at least one distribution vane pivotally mounted to the outlets to control the distribution of the fine particles in the various outlets by affecting the flow. An apparatus for separating coarse particles from a provided gas stream is disclosed.

WO 2009/093346 A JP 2006-098030 A US 06607079 B2

  An object of the present invention is to provide a solid-gas two-phase flow distribution device capable of effectively reducing the deviation of the distribution amount of the solid-gas two-phase flow, particularly in a pulverized coal combustion facility, An object of the present invention is to provide a solid-gas two-phase flow distribution device capable of making the distribution amount of pulverized coal to a fuel pipe more uniform than before, and achieving energy saving and cost reduction of the entire equipment.

  As a result of studying to solve the above problems, the present invention including the following aspects has been completed.

[1] A main container having a cylinder whose diameter increases from bottom to top and a ceiling plate that closes an opening of the cylinder with a larger diameter,
An inlet duct having a circular cross section for supplying a solid-gas two-phase flow into the main container;
It has two or more circular outlet ducts having a circular cross section for discharging the gas-solid two-phase flow from the main body container, and the same number of plate-like members as the number of the outlet ducts,
The ceiling panel has the same number of circular exit through holes as the number of exit ducts,
The exit through-holes are arranged such that their centers are located at the vertices of a regular polygon that is envisioned assuming the center of the ceiling plate as the center of gravity,
The outlet ducts are respectively connected to communicate with the main body container at the outlet through holes,
The inlet duct is connected so as to communicate with the main body container at the smaller diameter opening of the cylinder,
The plate-like member is installed so as to hang down on the lower surface of the ceiling plate, and the plate-like member has an upper surface that traverses an arc between two adjacent vertices on the circumcircle of the regular polygon, Are respectively arranged so as to be parallel to the direction radially emerging from the center of the board and perpendicular to the lower surface of the ceiling board,
Gas-solid two-phase flow distribution device.

[2] In the circumscribed circle of the regular polygon, the length l ₃ of the arc between the installation position of the plate-shaped member and the edge of the solid-gas two-phase flow downstream of the nearest outlet through hole from the position. And the arc length l ₄ between the installation position of the plate-like member and the edge of the nearest through hole on the upstream side of the solid-gas two-phase flow from the position, and the radius R ₁ of the circumscribed circle in the main body container , The vertical component V _a of the average flow velocity of the solid-gas two-phase flow at the position, the horizontal component V _t of the average flow velocity of the solid-gas two-phase flow at the position of the radius R ₁ of the circumscribed circle in the main container, and the height of the main container. H ₂ and the vertical length H ₁ of the plate-like member are:
L ₃ = l ₃ -H ₁ × V _t / V _a
S ₁ = L ₃ × H ₂
L ₄ = l ₄ + H ₁ × V _t / V _a
S ₂ = L ₄ × H ₂ -0.5 × H ₁ × H ₁ × V _t / V _a and S ₂ / (S ₁ + S ₂ ) ≧ 0.3
The dispensing device according to [1], wherein:

[3] The ratio L ₁ / D ₁ of the maximum length L ₁ in the horizontal direction of the plate member to the inner diameter D ₁ of the outlet through hole is larger than 0.7, and the height of the plate member with respect to the height H ₂ of the main body container. The dispensing device according to [1] or [2], wherein the ratio H ₁ / H ₂ of the maximum length H _{1 in} the vertical direction is larger than 0.7.
[4] Any one of [1] to [3], further including a wall protruding downward from the lower surface of the ceiling plate on the lower surface of the ceiling plate so as to turn the exit through hole along the edge of the exit through hole. A dispensing device according to any one of the preceding claims.
[5] the ratio L ₂ / D ₁ of the outlet through-hole outlet holes the Megurasu wall in the vertical direction length L ₂ to the inner diameter D ₁ of the is 0.025 to 0.25, according to [4] Dispensing equipment.

[6] The ceiling plate further has a circular additional through hole at the center thereof,
The inlet duct and the main container are arranged so as to have the same central axis,
Further comprising a powder supply pipe arranged along the central axis and having a circular cross section having an outer diameter smaller than the inner diameter of the inlet duct, extending from above the ceiling plate to the inside of the inlet duct through the additional through hole, The dispensing device according to any one of [1] to [5].

[7] A mill provided with the distribution device according to any one of [1] to [6].
[8] A boiler including the mill according to [7].

[9] Using the distribution device according to any one of [1] to [6],
Solid-gas two-phase flow is supplied into the main container via the inlet duct,
Discharging the solid-gas two-phase flow from the main body container through the outlet duct,
The gas-solid two-phase flow has a Stokes number of less than 1 in the main body container.
Gas-solid two-phase flow distribution method.
[10] The distribution method according to [9], wherein the particles contained in the solid-gas two-phase flow have a 50% diameter in a weight-based particle size distribution of 30 to 50 µm.

  ADVANTAGE OF THE INVENTION The distribution apparatus of the solid-gas two-phase flow of this invention can make the deviation of the distribution amount of a solid-gas two-phase flow substantially zero. The solid-gas two-phase flow distribution device of the present invention can make the distribution amount of pulverized coal to each fuel pipe of a furnace more uniform than before, particularly in a pulverized coal combustion facility, thereby saving energy and reducing costs of the entire facility. Reduction can be achieved.

It is the top view and schematic side view which show an example of the distribution apparatus of this invention. Is a diagram for explaining the ratio _{S 2 / (S 1 + S} 2). It is the top view and schematic side view which show another example of the dispensing apparatus of this invention. It is a figure showing an example of a mill provided with a distribution device of the present invention.

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by these examples.

  The solid-gas two-phase flow distribution device of the present invention includes a main body container 4, one inlet duct 1, two or more outlet ducts 2, and a plate-shaped member 5.

The main container has a cylinder whose diameter increases from bottom to top, and a ceiling plate 3 that closes the opening of the cylinder with the larger diameter.
The ratio R ₄ / R ₅ of the radius R ₄ of the larger-diameter opening of the cylinder to the radius R ₅ of the smaller-diameter opening of the cylinder is preferably 1.4 to 2.2.
The ceiling panel has the same number of circular outlet holes as the number of outlet ducts. The exit through-holes are arranged such that their centers are located at the vertices of a regular polygon imagined by considering the center of the ceiling plate as the center of gravity. The inner diameter D ₁ of the outlet through-holes are each the same. Further, the radius R ₁ of the circumscribed circle of the regular polygon, the ratio R ₁ / R ₄ to the radius R ₄ of the opening of the large diameter of the cylinder, preferably 0.6 to 0.9.

  The inlet duct is a tube having a circular cross section. The inlet duct is connected to communicate with the main body container at an opening having a smaller diameter of a cylinder constituting the main body container. Through the inlet duct, a solid-gas two-phase flow can be supplied into the main container.

The outlet duct is a tube having a circular cross section. Each of the outlet ducts is connected to communicate with the main body container through an outlet through hole provided in the ceiling plate. The gas-solid two-phase flow can be discharged from the main container via the outlet duct. The inner diameter of the outlet duct is substantially the same as the inner diameter D ₁ of the outlet through-hole.

The plate member has the same number as the number of outlet ducts. The plate-shaped member hangs down from the lower surface of the ceiling plate. The plate-like members are respectively arranged so as to cross the arc between two adjacent vertices on the circumscribed circle of the regular polygon. The plate member is installed such that its plate surface is parallel to a direction radially protruding from the center of the ceiling plate and perpendicular to the lower surface of the ceiling plate. A plate-like member of a preferred form is a member which can be rotated about an edge near the inner surface of the cylinder as an axis, and the plate surface can be tilted toward the inner surface of the cylinder.
It is preferable that the edge of the plate-shaped member on the side closer to the inner surface of the cylinder is located at the position of the vertex of a regular polygon envisioned assuming the center of the ceiling plate as the center of gravity. The radius R ₃ of the circumscribed circle of the regular polygon of the edge of the plate-like member on the side close to the inner surface of the cylinder has a ratio R ₃ / R ₄ to the radius R ₄ of the large-diameter opening of the cylinder, preferably 0.9 to 0.9. 0.95. It is preferable that the edge of the plate-shaped member, which is farther from the inner surface of the cylinder, be located at the position of the vertex of a regular polygon envisioned assuming the center of the ceiling plate as the center of gravity. The radius R ₂ of the circumscribed circle of the regular polygon on the edge of the plate-shaped member on the side remote from the inner surface of the cylinder has a ratio R ₂ / R ₄ to the radius R ₄ of the large-diameter opening of the cylinder, preferably 0.3 to 4.0. 0.6.

The plate member preferably has a plate surface in a shape such as a rectangle, a trapezoid, or a parallelogram. The plate-shaped member may or may not be in contact with the inner surface of the cylinder constituting the main body container. Further, it may or may not be in contact with the outer surface of the powder supply pipe.
Maximum length L ₁ of the horizontal plate member, the ratio L ₁ / D ₁ to the inner diameter D ₁ of the outlet through-holes tend to maximum flow rate deviation decreases at the outlet duct to more increase. The ratio L ₁ / D ₁ is preferably greater than 0.7.
Maximum length H ₁ in the vertical direction of the plate-like member, the ratio H ₁ / H ₂ to the height H ₂ of the main body container, there is a tendency that the maximum flow rate deviation decreases at the outlet duct to more increase. The ratio H ₁ / H ₂ is preferably greater than 0.7.

Further, in the present invention, the ratio _{S 2 / (S 1 + S} 2) tends to a maximum flow rate difference is reduced at the outlet duct to more increase. The ratio S ₂ / (S ₁ + S ₂ ) is preferably at least 0.3.
Note that S ₁ and S ₂ are values calculated by the following equations.
S ₁ = L ₃ × H ₂ = (l ₃ −H ₁ × V _t / V _a ) × H ₂
S ₂ = L ₄ × H ₂ -0.5 × H ₁ × H ₁ × V _t / V _a
= (L ₄ + H ₁ × V _t / V _a ) × H ₂ −0.5 × H ₁ × H ₁ × V _t / V _a
Here, l ₃ is the arc of the circumscribed circle of the radius R ₁ between the installation position of the plate-shaped member and the edge of the solid-gas two-phase flow downstream from the closest position opposite the outlet through hole. in length, l ₄ is the circumscribed circle of the radius R _1, the arc between the nearest exit through the hole edge on the upstream side of the plate-like member solid-gas two-phase flow from the installation position and the position of the in length, V _a is the vertical component of the average velocity of the solid-gas two-phase flow at the position of radius R ₁ of the circumscribed circle in a body vessel, V _t is the radius R of the circumscribed circle in a body vessel The horizontal component of the average flow velocity of the solid-gas two-phase flow at the position ₁ is H ₂ is the height of the main body container, and H ₁ is the maximum length of the plate member in the vertical direction.
V _a and V _t is the main body container, it occurs when the plate-like member 5-1 is not provided, based on the average flow velocity of the solid-liquid two-phase flow at the position of the circumscribed circle radius R _1, is determined. The average flow velocity V _a and V _t of the solid-liquid two-phase flow can be represented by a flow rate of solid particles. For example, it is effective to determine the flow velocity of the solid particles using CFD (Computational Fluid Dynamics). If the Stokes number is 1 or less, the trajectory of the solid particles roughly matches the streamline of the gas flow, so that a vector of the gas flow can be used.

The solid-gas two-phase flow distribution device according to a preferred embodiment of the present invention further includes a powder supply pipe 10. The powder supply pipe has an outer diameter smaller than the inner diameter of the inlet duct. Then, the powder supply pipe has a circular shape having the inlet duct 1 and the main body container 4 arranged so as to have the same central axis along the central axis from above the ceiling plate at the center of the ceiling plate. It is arranged to extend through an additional feed hole and into the inlet duct. Below the inlet duct or the powder supply pipe, there are means for crushing the powder supplied via the powder supply pipe, and means for causing the crushed powder to accompany the air flow to form a solid-gas two-phase flow. be able to. Then, the obtained solid-gas two-phase flow can be guided to the inlet duct. The ratio R ₆ / R ₅ of the outer radius R ₆ of the powder supply tube 10 to the radius R ₅ of the small diameter opening of the cylinder is preferably 0.3 to 0.6, and the ratio of the large diameter opening of the cylinder is small. the ratio R ₆ / R ₄ to the radius R ₄ is preferably 0.15 to 0.3.

The solid-gas two-phase flow distribution device according to a preferred embodiment of the present invention includes a wall protruding downward from the lower surface of the ceiling plate, in which the lower surface of the ceiling plate is provided with an outlet through hole along an edge of the outlet through hole. Has further. Vertical length L ₂ of the wall Megurasu the outlet through hole, the ratio L ₂ / D ₁ to the inner diameter D ₁ of the outlet through-holes, preferably 0.025 to 0.25, more preferably 0.05 Not less than 0.2. When the ratio L ₂ / D ₁ is in the above range, the particles flowing along the swirl flow collide with the wall, are dispersed, and go around to another outlet duct to discharge the particles. As a result, the maximum flow deviation at the outlet duct tends to decrease.

In the solid-gas two-phase flow used in the present invention, the Stokes number St in the main body container is preferably less than 1. In the case of St <1, the trajectory of the particles can be considered to substantially coincide with the streamline of the fluid.
St = (ρ _p d ² U) / (18ηL)
ρ _p = particle density (kg / m ³ ), d = particle diameter (m), U = typical flow velocity (m / s)
η = viscosity of fluid (kg / ms), L = typical length of flow (m)
The powder particles contained in the solid-gas two-phase flow used in the present invention preferably have a 50% diameter in a weight-based particle size distribution of 30 to 50 μm.

The mill of the present invention includes the solid-gas two-phase flow distribution device of the present invention. The boiler of the present invention includes the mill of the present invention.
FIG. 8 is a diagram illustrating an example of the mill of the present invention. A grinding table 15 and a grinding roller 14 are provided below the inlet duct 1. The coal 12 is supplied from the coal supply pipe 10 onto the pulverizing table, and the coal is pulverized. Air 11 is introduced into the mill through an air supply line (throat) 16. Air may be introduced using an air supply pipe configured to allow air to swirl and flow in the mill. The pulverized coal is sent upward with air. The coal is divided into coarse coal and fine coal by the classifier 13. Return the coarse coal to the grinding table. The pulverized coal enters the main container of the dispensing device from the inlet duct 1 together with the air. The gas-solid two-phase flow composed of pulverized coal and air is distributed by the plate member 5 to the outlet duct 2 with a small flow deviation. The solid-gas two-phase flow is supplied to the solid fuel burner of the furnace through the outlet duct 2 to burn the pulverized coal.

  INDUSTRIAL APPLICABILITY The distribution device of the present invention can be suitably used in a facility where a solid fuel such as coal is pulverized by a pulverizer in a coal-fired boiler plant or the like, and then supplied to a burner by an air stream and burned. Further, since the distribution device of the present invention can adjust and supply the distribution amount of the particulate solid fuel, it can be used in a multistage combustion system having a plurality of burners.

1: Inlet duct 2, 2-1, 2-2: Outlet duct 3: Ceiling plate 4: Main container 5, 5-1 and 5-2: Plate member

Claims (10)

A main body container having a cylinder expanding in diameter from bottom to top and a ceiling plate closing an opening of a larger diameter of the cylinder;
An inlet duct having a circular cross section for supplying a solid-gas two-phase flow into the main container;
It has two or more circular outlet ducts having a circular cross section for discharging the gas-solid two-phase flow from the main body container, and the same number of plate-like members as the number of the outlet ducts,
The ceiling panel has the same number of circular exit through holes as the number of exit ducts,
The exit through-holes are arranged such that their centers are located at the vertices of a regular polygon that is envisioned assuming the center of the ceiling plate as the center of gravity,
The outlet ducts are respectively connected to communicate with the main body container at the outlet through holes,
The inlet duct is connected so as to communicate with the main body container at the smaller diameter opening of the cylinder,
The plate-like member is installed so as to hang down on the lower surface of the ceiling plate, and the plate-like member has an upper surface that traverses an arc between two adjacent vertices on the circumcircle of the regular polygon, Are respectively arranged so as to be parallel to the direction radially emerging from the center of the board and perpendicular to the lower surface of the ceiling board,
Gas-solid two-phase flow distribution device. In the circumscribed circle of the regular polygon, an arc length l ₃ between the installation position of the plate-shaped member and the edge opposite the nearest outlet through hole downstream of the solid-gas two-phase flow from the position, and The position of the arc length l ₄ between the installation position of the plate member and the edge of the outlet through hole closest to the upstream of the solid-gas two-phase flow from the position, and the radius R ₁ of the circumscribed circle in the main body container the vertical component V _a of the average flow velocity of the solid-gas two-phase flow in a horizontal direction component V _t of the average flow velocity of the solid-gas two-phase flow at the position of radius R ₁ of the circumscribed circle in a body vessel, the main container height H ₂ , and the vertical length H ₁ of the plate member is
S ₁ = (l ₃ −H ₁ × V _t / V _a ) × H ₂
S ₂ = (l ₄ + H ₁ × V _t / V _a ) × H ₂ −0.5 × H ₁ × H ₁ × V _t / V _a and S ₂ / (S ₁ + S ₂ ) ≧ 0.3
The dispensing device according to claim 1, wherein Greater than the ratio L ₁ / D ₁ of the maximum horizontal length L ₁ of the plate-like member to the inner diameter D ₁ of the outlet through-hole is 0.7, and the plate-like member to the height H ₂ of the main body container in the vertical direction greater than the maximum ratio H ₁ / H ₂ of length H ₁ 0.7 the dispensing device of claim 1 or 2.   4. The lower surface of the ceiling plate, further comprising a wall protruding downward from the lower surface of the ceiling plate, turning the outlet through hole along the edge of the outlet through hole, according to any one of claims 1 to 3. Dispensing device. The ratio L ₂ / D ₁ of the outlet holes of the Megurasu wall in the vertical direction length L ₂ to the inner diameter D ₁ of the outlet holes is 0.025 to 0.25, the distribution device according to claim 4 . The ceiling plate further has a circular additional through hole at its center,
The inlet duct and the main container are arranged so as to have the same central axis,
Further comprising a powder supply pipe arranged along the central axis and having a circular cross section having an outer diameter smaller than the inner diameter of the inlet duct, extending from above the ceiling plate to the inside of the inlet duct through the additional through hole, The dispensing device according to claim 1.   A mill comprising the dispensing device according to any one of claims 1 to 6.   A boiler comprising the mill according to claim 7. Using the distribution device according to any one of claims 1 to 6,
Solid-gas two-phase flow is supplied into the main container via the inlet duct,
Discharging the solid-gas two-phase flow from the main body container through the outlet duct,
The solid-gas two-phase flow has a Stokes number of less than 1 in the main container.
Gas-solid two-phase flow distribution method.   The method according to claim 9, wherein the particles included in the solid-gas two-phase flow have a 50% diameter in a weight-based particle size distribution of 30 to 50 μm.

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