JP6331304B2 - Grand Flare - Google Patents

Description

  The present invention relates to a ground flare.

  For example, as shown in Patent Document 1, a ground flare including a windshield erected on the ground with the upper end open and a chimney disposed away from the bottom of the windshield includes a plurality of ground flares disposed in the chimney. Combustible exhaust gas is incinerated by a burner.

JP 2010-156508 A

  By the way, when viewed as a sound field, the ground flare having the structure as described above can be regarded as an open tube with both ends open. In such a sound field, an acoustic standing wave is generated that uses a burner as an excitation source and depends on the tube length in the tube axis direction (the length of the sound field). This acoustic standing wave propagates in the tube axis direction of the sound field as a plane wave.

  Here, as in the ground flare shown in Patent Document 1, when the burner is uniformly arranged over the entire area in the plane orthogonal to the tube axis direction, the heat source (burner) is uniformly in the plane with respect to the plane wave. The energy is transferred from and the same phenomenon as the thermoacoustic self-excited vibration is likely to occur. That is, energy is uniformly exchanged over the entire area of the plane wave, which causes the gas in the sound field to vibrate greatly. As a result, low frequency vibrations that resonate and vibrate surrounding objects occur.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to reduce the influence on the surroundings due to low-frequency vibration in a ground flare.

  In order to achieve the above object, in the present invention, as a first solving means, a windshield standing on the ground with its upper end open, and an air introduction that is provided inside the windshield and through which combustion air can pass freely And a chimney erected on the air introduction part, and a plurality of burners provided in the chimney, and the burner is installed in the chimney when viewed from above. The burner installation area and the burner non-installation area which is larger than the burner and where the burner is not installed are provided.

  Further, in the present invention, as the second solving means, in the first solving means, a burner group in which the arrangement pattern of the burners is the same and a plurality are arranged in the circumferential direction of the chimney is provided, and each burner group is provided. Employs a means in which at least one of the inter-group angles, which is an angle between adjacent burner groups as viewed from above, is arranged differently from the others.

  Further, in the present invention, as the third solving means, as the second solving means, in the range where the burner groups do not interfere with each other, the least common multiple of the plurality of inter-group angle values is maximized. The means that the group is arranged is adopted.

  According to the present invention, when viewed from above, the burner is provided with a burner installation area where the burner is installed and a burner non-installation area which is larger than the burner and where no burner is installed. . For this reason, the temperature of the burner installation region becomes higher than the temperature of the burner non-installation region, and the temperature distribution in the plane orthogonal to the tube axis of the sound field becomes non-uniform. Since the sound speed is higher in the high temperature region than in the low temperature region, the acoustic standing wave propagating in the sound field has a partially different velocity in the plane due to the uneven temperature distribution as described above. As a result, plane waves cannot be maintained. As a result, energy is not uniformly exchanged with respect to the acoustic standing wave in the plane orthogonal to the tube axis, and the gas in the sound field can be prevented from vibrating greatly. Therefore, according to the present invention, it is possible to reduce the influence on the surroundings due to the low frequency vibration in the ground flare.

It is a vertical sectional view showing the composition of ground flare A concerning one embodiment of the present invention. It is a vertical sectional view showing the composition of ground flare A concerning one embodiment of the present invention. (A) is a schematic diagram for demonstrating the effect | action in the ground flare A which concerns on one Embodiment of this invention, (b) is a schematic diagram for demonstrating the effect | action in the conventional ground flare. It is a vertical sectional view showing the configuration of a ground flare A1 that is a modification of the ground flare A according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The ground flare A according to the present embodiment is a facility for performing a combustion process on a combustible gas generated excessively in a plant as a processing target. This ground flare A is provided in, for example, an LNG base and heat-treats BOG gas (boil-off gas) inevitably generated in the LNG tank.

  As shown in FIGS. 1 and 2, the ground flare A includes at least a foundation 1, a windshield 2, an air introduction unit 3, a chimney 4, a plurality of burners 5, a supply pipe 6, and a control valve 7. The windshield 2 is generally called a “fence”, and the chimney 4 is also called a “stack”. Moreover, in FIG. 1, the cut surface of sectional drawing is set so that the burner installation area | region Ra and the burner non-installation area | region Rb which are mentioned later may be illustrated.

  The foundation 1 is a concrete structure constructed on the ground such that the upper surface is a horizontal plane. The windshield 2 is a cylindrical body erected on the ground with the upper end open. More specifically, the windshield 2 is a cylindrical body that is installed on the foundation 1 in a vertical state with no gap between the windshield 2 and the upper surface of the foundation 1. Further, the lower end of the windshield 2 is in contact with the upper surface of the foundation 1 all around, but the upper end of the windshield 2 is completely open.

  The air introduction part 3 is a substantially cylindrical opening constructed concentrically with the windshield 2 inside the windshield 2. For example, the air introduction part 3 is composed of a plurality of support columns arranged in the same ring at predetermined intervals, and is used for combustion over a predetermined height from the upper surface of the foundation 1 and over substantially the entire circumference. Air can pass freely.

  The chimney 4 is a cylindrical body provided on the air introduction part 3 in a vertical posture. The chimney 4 has the same diameter as the air introduction part 3 and has a predetermined length. The length (height) of the chimney 4 is set so that the flame generated in the plurality of burners 5 cannot be visually recognized from the outside, that is, the upper end of the chimney 4 is higher than the upper end of the flame.

  A plurality of burners 5 are provided in the chimney 4 and at a position (horizontal position) slightly higher than the upper end of the air introduction part 3 in the chimney 4 with a predetermined interval. Such a plurality of burners 5 are taken into the windshield 2 from the upper end of the windshield 2, and further, the combustion air taken into the chimney 4 through the air introduction part 3 is used as an oxidant to combustible gas ( To be treated.

  The supply pipe 6 is a pipe that supplies a plurality of burners 5 with a combustible gas (processing target). The supply pipe 6 passes through the windshield 2 and is drawn into the windshield 2, and is further drawn into the chimney 4 through the air introduction unit 3.

  The control valve 7 is provided on the supply pipe 6 outside the windshield 2. The control valve 7 is set to an open state when the combustible gas needs to be burned by the ground flare A, and is set to a closed state when the combustible gas is not required to be processed by the ground flare A. .

  Further, the characteristic configuration of the ground flare A will be described. As shown in FIG. 2, as viewed from above, the burner installation region Ra in which the burner 5 is installed in the chimney 4 and the size of one burner 5. And a burner non-installation region Rb where the burner 5 is not installed.

  The burner non-installation region Rb is a region where the burner 5 is not intentionally installed with respect to a space where the burner 5 can be installed. By providing this burner non-installation region Rb, the arrangement of the burners 5 in the chimney 4 when viewed from above is non-uniform.

  Moreover, in this grand flare A, the central burner 5a arrange | positioned in the center of the chimney 4 and the three (plural) burner groups 10 (the 1st burner group 11, the 2nd burner group 12, and the 3rd burner group 13) are comprised. I have. Each burner group 10 consists of five burners 5, and the arrangement pattern of these burners 5 is the same. These burner groups 10 are arranged in the circumferential direction of the chimney 4 with the central burner 5a as the center. That is, the present ground flare A includes a central burner 5 a and a plurality of burner groups 10 arranged in the circumferential direction of the chimney 4. In addition, each burner group 10 is arrange | positioned so that the arrangement pattern of the burner 5 which forms each may become point-symmetrical centering on the center burner 5a.

  A burner 5 is installed in an area where the burner group 10 is arranged, and this area is a burner installation area Ra. Moreover, the burner 5 is not installed in the area | region between the burner groups 10 in the circumferential direction of the chimney 4, This area | region becomes the burner non-installation area | region Rb.

  As shown in FIG. 2, a reference axis passing through the center of each burner group 10 is a reference axis L, and an angle between reference axes L of adjacent burner groups 10 when viewed from above is an inter-group angle. The inter-group angle between the reference axis L of the group 11 and the reference axis L of the second burner group 12 is the first inter-group angle θ1, and the reference axis L of the second burner group 12 and the reference axis L of the third burner group 13 are The inter-group angle is the second inter-group angle θ2, and the inter-group angle between the reference axis L of the third burner group 13 and the reference axis L of the first burner group 11 is the third inter-group angle θ3.

  In the ground flare A, the first group angle θ1, the second group angle θ2, and the third group angle θ3 are all set to different angles. For example, the first inter-group angle θ1 is set to 120 °, the second inter-group angle θ2 is set to 100 °, and the third inter-group angle θ3 is set to 140 °. This makes the arrangement of the burners 5 in the chimney 4 as viewed from above more uneven.

  As will be described later, in order to suppress the occurrence of low-frequency vibration, it is desirable that the arrangement of the burners 5 in the chimney 4 when viewed from above is as non-uniform as possible. For this reason, in the range where the burner groups 10 do not interfere with each other, the burner group 10 is set so that the least common multiple of the values of the first group angle θ1, the second group angle θ2, and the third group angle θ3 is the largest. Is preferably arranged.

Next, functions and effects of the present ground flare A will be described in detail.
In this ground flare A, when a combustible gas combustion process becomes necessary, the control valve 7 is set from the closed state to the open state by the plant control device, and a pilot burner (not shown) is operated by the plant control device. As a result, the burner 5 is ignited.

  Thus, when this grand flare A starts operation, the plurality of burners 5 burn the combustible gas (processing target) using the combustion air taken from the outside air through the air introduction unit 3 as an oxidant. However, noise (combustion noise) is generated in the chimney 4 with this combustion. Then, mainly due to this combustion noise, the windshield 2 and the chimney 4 resonate at their own natural frequencies and emit low frequency vibrations.

  Here, according to the ground flare A of this embodiment, when viewed from above, the burner installation region Ra in which the burner 5 is installed in the chimney 4 and the burner 5 which is wider than the size of the burner 5 are installed. A non-burner non-installation region Rb is provided. For this reason, the temperature of the burner installation area Ra becomes higher than the temperature of the burner non-installation area Rb, and the temperature distribution in the plane orthogonal to the tube axis of the chimney 4 becomes non-uniform.

  Since the acoustic velocity is higher in the high temperature region than in the low temperature region, the acoustic standing wave propagating in the chimney 4 has a partially different velocity in the plane due to the non-uniform temperature distribution. The plane wave cannot be maintained. That is, as shown in FIG. 3A, in the burner installation area Ra, the temperature is high and the sound speed is high, and in the burner non-installation area Rb, the temperature is low and the sound speed is slower than the burner installation area Ra.

  For this reason, as shown in FIG. 3B, when the burner 5 is installed uniformly in the chimney 4 as in the conventional ground flare, the acoustic standing wave H propagates as a plane wave. Thus, according to the ground flare A, the acoustic standing wave H is not a plane wave.

  According to the present ground flare A, energy is not uniformly transferred to the acoustic standing wave H in a plane orthogonal to the tube axis of the chimney 4, and the gas in the sound field vibrates greatly. Can be deterred. Therefore, according to the present ground flare A, it is possible to reduce the influence on the surroundings due to the low frequency vibration.

  Further, the present ground flare A includes a burner group 10 in which the arrangement pattern of the burners 5 is the same and a plurality of the burner groups 10 are arranged in the circumferential direction of the chimney 4, and includes a first group angle θ1 and a second group angle θ2. And the third group angle θ3 are all set to different angles. For this reason, the arrangement | positioning of the burner 5 in the chimney 4 when it sees from upper direction can be made more uneven, and the vibration suppression effect of gas increases more. In a range where the burner groups 10 do not interfere with each other, the burner group 10 is arranged so that the least common multiple of the values of the first group angle θ1, the second group angle θ2, and the third group angle θ3 is the largest. As a result, the arrangement of the burners 5 in the chimney 4 becomes more non-uniform, and the effect of suppressing gas vibration is further enhanced.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the said embodiment, the three burner groups 10 which consist of several burners 5 are provided, each burner group 10 is arranged in the circumferential direction of the chimney 4, and between these burner groups 10 burner non-installation area | region Rb However, the present invention is not limited to this. For example, as shown in the ground flare A1 shown in FIG. 4, the burners 5 may be arranged in the horizontal direction without being grouped, and the burner non-installation region Rb may be formed by removing a plurality of them.

(2) In the above embodiment, the three burner groups 10 are provided. However, the present invention is not limited to this. For example, two or four or more burner groups 10 may be provided so that the burner non-installation region Rb is provided.

(3) In the above embodiment, the first group angle θ1, the second group angle θ2, and the third group angle θ3 are all different angles. However, the present invention is not limited to this. For example, any of these inter-group angles may be the same value. That is, in the present invention, it is only necessary that the burner groups 10 are arranged so that at least one of the inter-group angles is different from the others.

  A ... Grand flare, A1 ... Grand flare, 1 ... Basic, 2 ... Wind shield, 3 ... Air introduction part, 4 ... Chimney, 5 ... Burner, 5a ... Center burner, 6 ... Supply pipe 7, control valve, 10 ... burner group, 11 ... first burner group, 12 ... second burner group, 13 ... third burner group, H ... acoustic standing wave, L ... reference axis , Ra …… Burner installation area, Rb …… Burner non-installation area

Claims (1)

A windshield erected on the ground with the upper end open, an air introduction part provided inside the windshield through which combustion air can pass, a chimney erected on the air introduction part, and the chimney In the ground flare comprising a plurality of burners provided in the inside,
When viewed from above, the chimney is provided with a burner installation area in which the burner is installed, and a burner non-installation area that is larger than the burner and in which the burner is not installed,
A plurality of burners arranged in the circumferential direction of the chimney with the same burner arrangement pattern;
An axis provided at the same location passing through the center in each of the burner groups is a reference axis,
Each of the burner groups is arranged so that all of the inter-group angles that are the angles of the reference axes of the adjacent burner groups when viewed from above are different.

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