Gasification furnace ash quenching device and method

Abstract

The invention belongs to the technical field of gasification furnaces, and relates to a gasification furnace ash quenching device and method.The device comprises an annular cooling pipe, nozzles and a cooling water header pipe; the nozzle is positioned in a hearth at the upper part of the waste boiler section of the gasification furnace body, is communicated with the annular cooling pipe and is used for spraying water mist into the hearth; the annular cooling pipe is sleeved outside a water cooling wall at the upper part of a waste boiler section of the gasification furnace body and is used for supporting and positioning the nozzle; the cooling water header pipe is arranged outside the gasification furnace body, is communicated with the annular cooling pipe and is used for providing spraying water for the nozzles through the annular cooling pipe. Water mist is sprayed into the hearth through the nozzle, the viscosity of the slag is reduced, the slag is discharged out of the waste boiler section after being quenched and solidified, and therefore the technical problems that slag adheres to the water cooling wall and a slag opening is blocked are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of gasifiers, and relates to a device and method for quenching ash and slag of a gasifier, and is particularly suitable for quenching ash and slag of a semi-waste boiler gasifier. Background Art

[0002] Gasifier is one of the commonly used equipment in coal chemical production, especially the multi-nozzle opposed waste boiler-quenching process gasifier, also known as semi-waste boiler gasifier. This gasifier body includes a combustion chamber section, a waste boiler section and a quenching chamber section. In actual production, the semi-waste boiler gasifier device can produce 9.0MPa high-pressure steam as a by-product and recover the sensible heat of high-temperature water gas. However, the following problems often occur during the operation of the gasifier:

[0003] (1) Water-cooled wall slag: The molten ash carried by the high-temperature coal gas from the waste boiler section has a high viscosity under high temperature conditions, so it will adhere to the surface of the water-cooled wall. As the ash continues to adhere and accumulate, the by-product steam of the waste boiler section will decay;

[0004] (2) Slag outlet blockage: When the byproduct steam in the gasifier decays, the heat of the waste boiler section gas moves downward, the ash becomes sticky and accumulates at the slag outlet, causing the slag outlet to be blocked, making it difficult for the ash to fall;

[0005] (3) Overheating of the bottom of the combustion chamber: When the lower slag outlet is blocked, the high-temperature coal gas in the gasifier flows back into the interlayer of the gasifier, causing overheating of the bottom of the combustion chamber, affecting the stable operation of the gasification device.

[0006] In summary, the problems of water-cooled wall hanging slag and slag outlet blockage in the operation of the existing semi-waste boiler gasifier seriously restrict the long-term stable operation of the device. Summary of the invention

[0007] Aiming at the technical problem that the existing semi-waste boiler gasifier has water-cooled wall hanging slag, which leads to a shortened operation period of the gasifier, the present invention provides a gasifier ash quenching device and method.

[0008] The present invention arranges a nozzle in the furnace above the waste boiler section of the gasifier body to spray water mist into the furnace to spray and wash the slag, reduce the viscosity of the slag, quench and solidify the slag, and then discharge it from the waste boiler section, thereby solving the technical problems of water-cooled wall slag hanging and slag mouth blockage.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A gasifier ash quenching device comprises an annular cooling pipe, a nozzle and a cooling water main pipe;

[0011] The nozzle is located in the furnace at the upper part of the waste boiler section of the gasifier body, and the nozzle is connected to the annular cooling pipe and is used to spray water mist into the furnace;

[0012] The annular cooling pipe is sleeved on the outside of the water-cooled wall at the upper part of the waste boiler section of the gasifier body, and is used to support and position the nozzle and provide spray water to the nozzle;

[0013] The cooling water main pipe is arranged outside the gasifier body and communicated with the annular cooling pipe, and is used for providing spray water into the annular cooling pipe.

[0014] It is further defined that the nozzle passes through the water-cooled wall and is connected to the annular cooling pipe; the nozzle is installed in a direction perpendicular to the upper inclined surface of the water-cooled wall; and the nozzle outlet is inclined toward the center of the gasifier body.

[0015] It is further defined that the length of the nozzle in the furnace is 70 to 100 mm; and the angle between the spraying direction of the nozzle and the vertical direction of the water-cooled wall is 30° to 60°.

[0016] It is further defined that the number of the nozzle is one or more; when there are multiple nozzles, the multiple nozzles are evenly distributed on the annular cooling pipe around the same circumference of the gasifier body.

[0017] It is further defined that the pressure difference between the spray water and the pressure in the furnace is 7 MPa.

[0018] It is further defined that the gasifier ash quenching device also includes a nitrogen main pipe located outside the gasifier body and connected to the cooling water main pipe.

[0019] As described in the ash quenching method of the gasification furnace ash quenching device, the ash quenching method comprises the following steps:

[0020] S1. The gasifier ash quenching device is installed outside the gasifier body, on the water-cooled wall above the waste boiler section of the gasifier body, and in the furnace above the waste boiler section of the gasifier body;

[0021] S2. When slag enters the furnace of the waste boiler section of the gasifier body, spray water passes through the cooling water main pipe, the annular cooling pipe and the nozzle in sequence to form water mist and spray to the slag, thereby reducing the viscosity of the slag and quenching and solidifying the slag.

[0022] It is further defined that in step S2, the spraying water is 13.5 MPa high-pressure boiler water, and the water mist sprayed from multiple nozzles crosses each other inside the furnace to form an annular water curtain, which is sprayed towards the slag.

[0023] It is further defined that, before the gasifier body is operated in step S2, nitrogen cooling protection is provided to the nozzle through the nitrogen main pipe.

[0024] Compared with the prior art, the technical effects of the present invention are:

[0025] 1. The present invention arranges a nozzle in the furnace above the waste boiler section of the gasifier body to spray water mist into the furnace, sprays the molten ash in the waste boiler section, reduces the viscosity of the molten ash, quenches and solidifies the molten ash in advance, and then when the molten ash is discharged from the waste boiler section, it is not easy to adhere to the surface of the water-cooled wall due to its low viscosity, thereby solving the technical problems of slag hanging on the water-cooled wall and slag port blockage, and avoiding steam attenuation.

[0026] 2. In the present invention, the nozzle sprays toward the center of the furnace of the gasifier, and there is an angle between the spray direction and the vertical direction of the water-cooled wall. The nozzle opening is in the form of a flat mouth opening, which can better contact with the coal gas, greatly reduce the water gas temperature, solidify the slag, and avoid the occurrence of slag hanging on the water-cooled wall.

[0027] 3. In the present invention, there are multiple nozzles, and the length of the nozzles in the furnace is 70mm-100mm; the angle between the spray direction of the nozzles and the vertical direction of the water-cooled wall is 30°-60°. The water mist formed in this way intersects each other inside the furnace, forming an annular water curtain without dead angles, spraying and quenching the ash entering the waste boiler section to the greatest extent, thereby improving the quenching effect.

[0028] 4. In the present invention, a nitrogen main pipe connected to a cooling water main pipe is arranged outside the gasifier body. Before operation, cooling medium is provided to the nozzle through the nitrogen main pipe to ensure stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the ash quenching device provided in Example 1;

[0030] Figure 2 It is a top view schematic diagram of the annular cooling tube;

[0031] Figure 3 It is a schematic diagram of the main view of the annular cooling tube;

[0032] Figure 4 It is a schematic diagram of the connection between the annular cooling tube and the water-cooled wall;

[0033] Figure 5 A schematic diagram of the ash quenching device provided in Example 2;

[0034] in:

[0035] 10-gasifier body; 20-water-cooled wall; 201-water-cooled wall tube bundle; 202-fin; 30-annular cooling pipe; 310-first semicircular annular pipe; 311-first water inlet; 312-first mounting hole; 320-second semicircular annular pipe; 321-second water inlet; 322-second mounting hole; 40-nozzle; 50-first cooling water branch pipe; 60-second cooling water branch pipe; 70-cooling water main pipe; 80-first water inlet stop valve; 90-second water inlet stop valve; 100-boiler feed water pipe; 110-blind flange; 120-nitrogen main pipe; 130-first nitrogen stop valve; 140-second nitrogen stop valve; 150-third nitrogen stop valve; 160-check valve; 170-pneumatic shut-off valve. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the following embodiments, the gasifier ash refers to the molten ash carried in the high-temperature coal gas, also referred to as molten slag.

[0038] Example 1

[0039] See also Figure 1 The gasifier ash quenching device provided in this embodiment includes an annular cooling pipe 30, a nozzle 40 and a cooling water main pipe 70.

[0040] In this embodiment, the nozzle 40 is located in the furnace at the upper part of the waste boiler section of the gasifier body 10. The nozzle 40 is connected to the annular cooling pipe 30 and is used to spray water mist into the furnace.

[0041] In this embodiment, the annular cooling pipe 30 is sleeved on the outside of the water-cooled wall 20 at the upper part of the waste boiler section of the gasifier body 10, and is used to provide support and positioning for the nozzle 40 and to provide spray water to the nozzle 40. Since the annular cooling pipe 30 is sleeved on the outside of the water-cooled wall 20, it plays a supporting role, and since the nozzle 40 is arranged on the annular cooling pipe 30, it plays an installation and positioning role; in addition, spray water is also provided to the nozzle 40 through the annular cooling pipe 30.

[0042] In this embodiment, the cooling water main pipe 70 is disposed outside the gasifier body 10 and is in communication with the annular cooling pipe 30 , and is used to provide spray water into the annular cooling pipe 30 .

[0043] In this embodiment, the nozzle 40 passes through the water-cooled wall 20 and is connected to the annular cooling pipe 30; the nozzle 40 is installed perpendicular to the upper slope of the water-cooled wall; in order to better contact with the coal gas, the outlet of the nozzle 40 is inclined toward the center of the gasifier body 10.

[0044] In this embodiment, the length of the nozzle 40 in the furnace is 70 mm to 100 mm; the angle between the spray direction of the nozzle 40 and the vertical direction of the water-cooled wall 20 is 30° to 60°. Preferably, the angle is 45°.

[0045] During implementation, the nozzle 40 is made of 316L material, has a width of 8 mm, and has a flat opening.

[0046] See also Figure 1 and Figure 4 In this embodiment, the water-cooled wall 20 is a tubular structure, with water-cooled wall tube bundles 201 distributed inside, and fins 202 are arranged between the water-cooled wall tube bundles 201. When the nozzle 40 passes through the water-cooled wall 20, a through hole is arranged on the fins 202 between the water-cooled wall tube bundles 201, and the nozzle 40 extends into the waste boiler section furnace 100mm through the through hole. After all the nozzles 40 are arranged and installed, the fins 202 and the outer wall of the nozzle 40 are sealed and welded to ensure that there is no channeling between the waste boiler section furnace and the interlayer.

[0047] See also Figure 2 and Figure 3 In this embodiment, in order to facilitate the installation of the annular cooling pipe 30 on the outside of the water-cooled wall 20, the annular cooling pipe 30 is an annular structure composed of a first semicircular annular pipe 310 and a second semicircular annular pipe 320; the first semicircular annular pipe 310 and the second semicircular annular pipe 320 are both sleeved on the outer wall of the water-cooled wall 20 in the gasifier body 10; the nozzle 40 is set at the bottom of the first semicircular annular pipe 310 and the bottom of the second semicircular annular pipe 320; the cooling water main pipe 70 is connected to the inside of the first semicircular annular pipe 310 and the inside of the second semicircular annular pipe 320 respectively.

[0048] In this embodiment, the interior of the first semicircular annular tube 310 and the second semicircular annular tube 320 are both 1 / 2 annular tubes with both sides blocked, and the first semicircular annular tube 310 and the second semicircular annular tube 320 have the same number of nozzles 40.

[0049] Preferably, in order to facilitate the installation and connection of the nozzle 40 and the annular cooling tube 30, a first mounting hole 312 is set at the bottom of the first semicircular annular tube 310, the number of the first mounting holes 312 is the same as the number of the nozzles 40, each first mounting hole 312 is connected to a corresponding nozzle 40, and the nozzles 40 are welded to the first mounting holes 312; a second mounting hole 322 is set at the bottom of the second semicircular annular tube 320, the number of the second mounting holes 322 is the same as the number of the nozzles 40, each second mounting hole 322 is connected to a corresponding nozzle 40, and the nozzles 40 are welded to the second mounting holes 322.

[0050] Preferably, in order to facilitate the installation and connection of the cooling water main pipe 70 and the annular cooling pipe 30, a first water inlet 311 is provided on the top of the first semicircular annular pipe 310, and the cooling water main pipe 70 is connected to the first semicircular annular pipe 310 through the first water inlet 311; a second water inlet 321 is provided on the top of the second semicircular annular pipe 320, and the cooling water main pipe 70 is connected to the second semicircular annular pipe 320 through the second water inlet 321. When connected, the cooling water main pipe 70 is connected to the first water inlet 311 and the second water inlet 321 by welding.

[0051] In this embodiment, there are one or more nozzles 40 , and the plurality of nozzles 40 are evenly distributed on the annular cooling pipe 30 around the same circumference of the gasifier body 10 .

[0052] Preferably, the tube diameter of the first semicircular annular tube 310 and the tube diameter of the second semicircular annular tube 320 are both 28 mm.

[0053] In this embodiment, considering that when no spray medium is introduced into the inner side of the water-cooled wall after blocking, the high temperature in the furnace will damage the nozzle, which will cause the nozzle to break, causing the high-pressure boiler water to flow into the interlayer, so the number of nozzles should not be too large. Preferably, according to the diameter of the gasifier 10 and the diameter of the water-cooled wall 20, there are 12 nozzles 40, which are evenly distributed in a circle on the annular cooling pipe 30 and along the circumference of the gasifier 10.

[0054] Preferably, six first mounting holes 312 are provided at the bottom of the first semicircular ring tube 310 , and six second mounting holes 322 are provided at the bottom of the second semicircular ring tube 320 .

[0055] In this embodiment, the cooling water main pipe 70 is led out from the boiler water supply pipe 100; at the same time, a blind flange 110 is reserved on the gasifier body 10, the cooling water main pipe 70 is located outside the gasifier body 10, and one end of the cooling water main pipe 70 is connected to the boiler water supply pipe 100, and the other end of the cooling water main pipe 70 passes through the blind flange 110 and enters the gasifier body 10, and is placed in the waste boiler section interlayer and communicates with the inside of the annular cooling pipe 30. The interlayer is a cavity layer formed between the inner wall of the waste boiler section of the gasifier body 10 and the outer wall of the water-cooled wall 20. Due to the expansion change of the water-cooled wall 20 before and after operation, the cooling water main pipe 70 is provided with a "U"-shaped elbow before being incorporated into the annular cooling pipe 30 for thermal expansion compensation. Specifically, the cooling water main pipe 70 is connected to the annular cooling pipe 30 through the first cooling water branch pipe 50 and the second cooling water branch pipe 60. The first cooling water branch pipe 50 and the second cooling water branch pipe 60 form a structure similar to a "U"-shaped elbow, which plays a role in thermal expansion compensation.

[0056] In this embodiment, in order to facilitate the connection between the cooling water main pipe 70 and the first semicircular annular pipe 310 and the second semicircular annular pipe 320 , a first cooling water branch pipe 50 and a second cooling water branch pipe 60 are arranged above the annular cooling pipe 30 .

[0057] The first cooling water branch pipe 50 is an L-shaped pipe formed by connecting the first transverse pipe and the first longitudinal pipe, and the first transverse pipe is an arc-shaped structure matching the outer wall of the water-cooled wall 20; the second cooling water branch pipe 60 is an L-shaped pipe formed by connecting the second transverse pipe and the second longitudinal pipe, and the second transverse pipe is an arc-shaped structure matching the outer wall of the water-cooled wall 20, and the first transverse pipe and the second transverse pipe form a ring structure. During implementation, the first transverse pipe and the second transverse pipe are sleeved on the outer wall of the water-cooled wall 20, and the cooling water main pipe 70 is respectively connected to the first transverse pipe and the second transverse pipe, the first longitudinal pipe is located above the first semicircular annular pipe 310 and is connected to the inside of the first semicircular annular pipe 310 through the first water inlet 311; the second longitudinal pipe is located above the second semicircular annular pipe 320 and is connected to the inside of the second semicircular annular pipe 320 through the second water inlet 321.

[0058] In this embodiment, in order to facilitate the control of the entry of the spraying medium into the cooling water main pipe 70, a first water inlet stop valve 80 and a second water inlet stop valve 90 are arranged in sequence on the cooling water main pipe 70 along the water inlet direction; according to the actual needs of the gasifier, the first water inlet stop valve 80 and the second water inlet stop valve 90 are opened or closed, which is easy to operate.

[0059] When in use, the spray medium (13.5MPa high-pressure boiler water) flows out from the boiler feed water pipe 100, passes through the cooling water main pipe 70, and enters the first cooling water branch pipe 50 and the second cooling water branch pipe 60 respectively after passing through the first water inlet stop valve 80 and the second water inlet stop valve 90 in sequence, and then enters the 12 nozzles 40 through the first semicircular annular pipe 310 and the second semicircular annular pipe 320 respectively. The spray medium is sprayed into the upper furnace of the waste boiler section of the gasifier body 10 through the nozzles 40. Since the pressure difference between the spray medium and the furnace is 7MPa a. The water mist formed by the 12 nozzles 40 distributed on the upper part of the waste boiler section crosses each other inside the furnace to form a ring-shaped water curtain without dead corners, spraying the high-temperature coal gas entering the waste boiler section, reducing the temperature of the high-temperature water coal gas leaving the combustion chamber section and reducing the temperature of the molten ash carried in the high-temperature coal gas, so that the coal gas temperature is reduced, the molten ash is quenched and solidified, thereby reducing the viscosity of the molten ash, making it difficult for the molten ash coming out of the waste boiler section to adhere to the water-cooled wall, avoiding slag hanging on the water-cooled wall and slag accumulation to cause slag blockage, thereby ensuring the service life of the gasifier.

[0060] Example 2

[0061] See also Figure 5 On the basis of Example 1, the gasifier ash quenching device provided in this embodiment further includes a nitrogen main pipe 120 located outside the gasifier body 10 and connected to the cooling water main pipe 70.

[0062] The function of the nitrogen main pipe 120 is to provide nitrogen cooling protection to the nozzle 40 through the nitrogen main pipe 120 before the gasifier is started.

[0063] In this embodiment, the connection end between the nitrogen main pipe 120 and the cooling water main pipe 70 is located at the rear end of the second water inlet stop valve 90 , that is, the nitrogen in the nitrogen main pipe 120 directly flows into the cooling water main pipe 70 without passing through the second water inlet stop valve 90 .

[0064] In this embodiment, in order to control the introduction of nitrogen, a first nitrogen shut-off valve 130, a second nitrogen shut-off valve 140 and a third nitrogen shut-off valve 150 are sequentially arranged on the nitrogen main pipe 120 along the direction of the airflow entering; the introduction of nitrogen is controlled by the three nitrogen shut-off valves, and the control is accurate.

[0065] In this embodiment, since the nitrogen main pipe 120 is provided, a check valve 160 and a pneumatic shut-off valve 170 are also provided on the cooling water main pipe 70 between the nitrogen main pipe 120 and the outer wall of the gasifier body 10. The pneumatic shut-off valve 170 is close to the gasifier body 10, and the check valve 160 and the second water inlet stop valve 90 are arranged on both sides of the nitrogen main pipe 120. The pipeline between the nitrogen main pipe 120 and the gasifier body 10 is cut off by the pneumatic shut-off valve 170, and the backflow of coal gas is prevented by the check valve 160.

[0066] Example 3

[0067] In this embodiment, the gasifier ash quenching device of Embodiment 1 or Embodiment 2 is used to quench the gasifier ash.

[0068] The method for quenching ash and slag of a gasifier provided in this embodiment comprises the following steps:

[0069] S1. The gasifier ash quenching device of Example 1 or Example 2 is correspondingly installed outside the gasifier body 10, on the water-cooled wall 20 above the waste boiler section of the gasifier body 10, and in the furnace above the waste boiler section of the gasifier body 10.

[0070] Specifically, the cooling water main pipe 70, the annular cooling pipe 30 and the nozzle 40 are correspondingly installed outside the gasifier body 10, the water-cooled wall 20 above the waste boiler section of the gasifier body 10, and the furnace above the waste boiler section of the gasifier body 10.

[0071] S2. When slag enters the furnace of the waste boiler section of the gasifier body 10, spray water passes through the cooling water main pipe 70, the annular cooling pipe 30 and the nozzle 40 in sequence to form water mist and spray to the slag to reduce the viscosity of the slag and quench and solidify the slag;

[0072] S3. After quenching and solidification, the slag continues to be discharged downward from the waste pot section.

[0073] In step S2, the pressure difference between the spray water and the pressure in the furnace is 7 MPa, the spray water is 13.5 MPa high-pressure boiler water, and the water mist sprayed from multiple nozzles 40 crosses each other inside the furnace to form an annular water curtain. There is no dead zone when spraying to the molten ash, thereby improving the quenching effect.

[0074] In step S2 of this embodiment, before the gasifier body 10 starts working, nitrogen spray is provided to the nozzle 40 through the nitrogen main pipe 120 to ensure stable operation of the gasifier.

[0075] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A gasifier ash quenching device, characterized in that: It comprises an annular cooling pipe (30), a nozzle (40) and a cooling water main pipe (70); The nozzle (40) is located in the furnace at the upper part of the waste boiler section of the gasifier body (10), and the nozzle (40) is connected to the annular cooling pipe (30) and is used to spray water mist into the furnace; The annular cooling pipe (30) is sleeved on the outside of the water-cooled wall (20) at the upper part of the waste boiler section of the gasifier body (10) and is used to support and position the nozzle (40) and provide spray water to the nozzle (40); The cooling water main pipe (70) is disposed outside the gasifier body (10) and is in communication with the annular cooling pipe (30) and is used to provide spray water into the annular cooling pipe (30).

2. The gasifier ash quenching device according to claim 1, characterized in that: The nozzle (40) passes through the water-cooled wall (20) and is connected to the annular cooling pipe (30); the installation direction of the nozzle (40) is perpendicular to the upper inclined surface of the water-cooled wall; the outlet of the nozzle (40) is inclined toward the center position of the gasifier body (10).

3. The gasifier ash quenching device according to claim 2, characterized in that: The length of the nozzle (40) in the furnace is 70 mm to 100 mm; the angle between the spraying direction of the nozzle (40) and the vertical direction of the water-cooled wall (20) is 30° to 60°.

4. The gasifier ash quenching device according to claim 3, characterized in that: There are one or more nozzles (40); when there are multiple nozzles (40), the multiple nozzles (40) are evenly distributed on the annular cooling pipe (30) around the same circumference of the gasifier body (10).

5. The gasifier ash quenching device according to claim 4, characterized in that: The gasifier ash quenching device further comprises a nitrogen main pipe (120) located outside the gasifier body (10) and connected to the cooling water main pipe (70).

6. The slag quenching method formed by the gasification furnace slag quenching device according to claim 5 is characterized in that: The ash quenching method comprises the following steps: S1. The gasifier ash quenching device according to claim 5 is installed correspondingly outside the gasifier body (10), on the water-cooled wall (20) above the waste boiler section of the gasifier body (10), and in the furnace above the waste boiler section of the gasifier body (10); S2. When slag enters the furnace of the waste boiler section of the gasifier body (10), spray water passes through the cooling water main pipe (70), the annular cooling pipe (30) and the nozzle (40) in sequence to form water mist and spray toward the slag, thereby reducing the viscosity of the slag and quenching and solidifying the slag.

7. The slag quenching method according to claim 6, characterized in that: In step S2, the spraying water is 13.5 MPa high-pressure boiler water, and the water mist sprayed by multiple nozzles (40) crosses each other inside the furnace to form an annular water curtain, which is sprayed towards the slag.

8. The ash quenching method according to claim 7, characterized in that: In the step S2, before the gasifier body (10) starts working, nitrogen cooling protection is provided to the nozzle (40) through the nitrogen main pipe (120).

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