JPS6030405B2 - ground flare system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground flare system,
The purpose is to ensure the safety of plants that emit process gases.

A ground flare is a device that completely combusts and incinerates potentially toxic process gases released from safety valves in various plants such as oil refining, petrochemicals, steel manufacturing, and steel manufacturing.

Due to its nature, ground flares have rapid load fluctuations.
If the treated gas is directly introduced into the furnace, black smoke will be generated due to a lack of combustion air, the flame will blow out due to a sudden decrease in the amount of gas (below the control range of the burner), and the gas will be expelled due to this. emission, abnormal vibration due to flame instability,
Abnormal noise occurs. Therefore, in order to solve this problem, the secondary ground flare is equipped with an automatic valve in the gas piping, so that a staged combustion state commensurate with the amount of gas to be processed can be obtained. Figures 1 and 2
A conventional ground flare system will be explained based on the diagram.
Reference numeral 1 denotes a ground flare, which has burner assemblies 2, 3, and 4 in multiple stages.

That is, the burner assemblies 2, 3, 4 include a plurality of burners 2A,
3A and 4A are arranged in an annular shape, and the burner assemblies 2, 3, and 4 of each stage are arranged concentrically. The number of individual burners forming each burner assembly 2, 3, 4 ranges from tens to hundreds. Therefore, each burner 2A, 3A,
Attaching a pilot burner to each of the 4A increases pilot gas consumption. Therefore, in general, the first stage burner assembly 2 includes one to several dozen pilot burners 5.
is attached, and when processing gas is released from the plant side, first the first stage burner assembly 2 is ignited by the pilot burner 5, and then the burner assembly 3, 4 from the second stage onward is ignited.
A system is adopted in which the burners are sequentially ignited by the torches from the burner assemblies 2 and 3 in the previous stage. On the other hand, the process gas is introduced into the burner assemblies 2, 3, and 4 at each stage using a plant safety valve (not shown).

), etc., through separate processing gas introduction pipes 7A, 7B, and 7C that are connected in a branched manner to the processing gas conduit 6. In these processing gas introduction pipes 7A, 7B, and 7C, pressure detectors 8A and 8B are interposed in the first stage and the second stage (pre-final stage), respectively, and pressure detectors 8A and 8B are interposed in the first stage and the second stage (pre-final stage), and pressure detectors 8A and 8B are interposed in the second stage and the final stage. Automatic valves 9A and 9B are respectively interposed therein. The self-operating valves 9A and 9B are controlled to open and close by signals from the pressure detectors 8A and 8B in the preceding stage. That is, the processing gas released from the plant first flows through the first-stage processing gas introduction pipe 7A and is burned in the first-stage burner assembly 2. When the internal pressure of the first-stage processing gas introduction pipe 7A increases due to an increase in the amount of processing gas, this is automatically detected by the pressure detector 8A, and the automatic valve 9A is thereby opened. Therefore, the process gas is combusted both in the first stage burner assembly 2 and in the second stage burner assembly 3. Similarly, when the amount of treated gas increases further, the automatic valve 9B is opened and the treated gas is combusted in the burner assemblies 2, 3, and 4 of all stages. On the other hand, when the amount of processing gas decreases, the automatic valve 9A of the previous stage is closed from the automatic valve 9B interposed in the final stage processing gas introduction pipe 7C to the top corresponding to the amount of decrease. Incidentally, one is a shield ram interposed in the process gas conduit 6 to prevent flashback. Such conventional systems potentially have the following drawbacks: '1' If the automatic valve 9B interposed in the third-stage processing gas inlet pipe 7C does not close due to some kind of trouble. If the automatic valve 9B does not close due to a failure and gas is released again, the processing Gas flows only to the first stage burner assembly 2 and the third stage burner assembly 4, and does not flow to the second stage burner assembly 3.

Therefore, the third-stage burner assembly 4 cannot receive the fire from the second-stage burner assembly 3, so a large amount of processing gas is released into the furnace in an undisturbed state, and if the furnace is full, posing a risk of explosion. ■ Automatic valve 9A, 9
If B does not open due to some trouble, automatic valve 9
If A and 9B do not open, the back pressure of the safety valve on the plant side may increase and the safety valve may not operate properly, creating the possibility of a plant explosion accident.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art, and an embodiment thereof will be described below with reference to FIGS. 3 and 4.

11 is a ground flare, and 12, 13, and 14 are a first-stage burner assembly, a second-stage burner assembly, and a third-stage burner assembly, respectively.

As is clear from FIG. 4, the first-stage burner assembly 12 has burners arranged in a cross shape inside the furnace of the ground flare 11, and the third-stage burner assembly 14 has the first-stage burner assembly 12 arranged in a cross-shaped manner inside the furnace of the ground flare 11. Each burner is arranged in an annular shape including 12 outermost burners 12A, and the second stage burner assembly 13 is arranged between the first stage burner assembly 12 and the third stage burner assembly 14. The assembly 12 is arranged in an annular shape including the intermediate burner 128 . And pie. Burna 15
are installed near the burner 12C located at the center of the furnace or near each of all first-stage burners. According to such a burner arrangement, even if processing gas does not flow to the second stage burner assembly 13 due to a failure of the automatic valve 9A, the third stage burner assembly 1
4, it is ignited by the burner flame of the first stage burner assembly 12. Even when the burner assembly is configured in three or more stages, the same effect can be achieved based on the arrangement shown in the illustrated example. 16 is a bypass line extending from the inlet side to the outlet side of the automatic valve 9A interposed in the third stage processing gas introduction pipe 7B, and a water sealing device 17 is connected to this bypass line 16.
is mediated.

Further, 18 is a bypass line extending from the inlet side to the outlet side of the automatic valve 9B interposed in the third stage processing gas introduction pipe 7C, and a water sealing device 19 is interposed in this bypass line 18. The two water sealing devices 17 and 19 each include drums 17A and 19A filled with water, and inlet pipes extending from the inlet sides of the automatic valves 9A and 9B and inserted at a certain depth L, 1 into the filled water. It consists of 16A, 18A and outlet pipes 16B, 18B. In this way, if the automatic valve 9A fails to open, for example, the water seal of the water seal device 17 is broken and the process gas flows to the second stage burner assembly 13 through the bypass line 16. If the automatic valve 9B fails and does not open, the water sealing device 19 operates in the same manner. If the amount of gas to be processed decreases, there is no problem because the water seal is maintained when the pressure falls below the set pressure of the water seal devices 17 and 19. The set pressure for opening and closing automatic valves 9A and 9B is 300 to 80, depending on the back pressure of the safety valve on the plant side and the performance of the burner.
Set pressure for closing Aq Aq is set to 10 to 10 Aq Aq.

If the processing gas flows through the water sealing devices 17 and 19 under these conditions, if the gas amount decreases, the gas pressure after the water sealing devices 17 and 19 will drop to 10 Aq or less, which may cause abnormal vibrations and abnormal noise. However, this vibration and noise are not harmful to the equipment, and only last for a short time.
Also, since the frequency is about once every few years, it is not a problem. As is clear from the above description, according to the present invention, the burners of the first-stage burner assembly are arranged in a cross shape in the ground flare furnace, so that the second- and third-stage burner assemblies are connected to the first-stage burner assembly. The assembly ensures ignition, and furthermore, automatic valves are installed in each stage of processing gas introduction pipes from the second stage processing gas introduction pipe to the final stage processing gas introduction pipe, and these automatic valves The automatic valves are opened and closed by signals from the pressure detectors in the processing gas introduction pipes before and after the valves, and a bypass line is provided from the inlet side to the outlet side of each automatic valve, and a water sealing device is interposed in this bypass line. , even if the automatic valve fails, the process gas will flow through the bypass line to the ground flare, preventing the operation of the safety valve on the plant side and creating a risk of explosion. This can be prevented.

[Brief explanation of the drawing]

Figures 1 and 2 show conventional examples; Figure 1 is an explanatory diagram;
The figure is a burner arrangement diagram, FIGS. 3 and 4 show embodiments of the present invention, FIG. 3 is an explanatory diagram, and FIG. 4 is a burner arrangement diagram. 6... Processing gas conduit, 7A, 7B, 7C...
... Processing gas inlet pipe, 8A, 8B... Pressure detector, 9A, 9B... Automatic valve, 11...
- Grand flare, 12, 13, 14... Burner assembly, 16, 18. ．．・．． ...Bypass line, 1
7,19... Water sealing device. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Each ground flare is composed of a first-stage burner assembly, a second-stage burner assembly, and a third-stage burner assembly, and each burner of the first-stage burner assembly is arranged in a cross shape in the furnace of the ground flare, The burners of the third stage burner assembly are arranged in a ring shape including the outermost burner of the first stage burner assembly on the inner periphery of the furnace, and each burner of the second stage burner assembly is arranged in a ring shape including the outermost burner of the first stage burner assembly. A plurality of processing gas introduction pipes branched from a common processing gas conduit are arranged in an annular shape including an intermediate portion between the outermost burner and the central burner, and are individually connected to each burner assembly of the ground flare. A pressure detector is interposed in each processing gas introduction pipe from the first stage processing gas introduction pipe to the final stage processing gas introduction pipe, and a pressure detector is inserted in each processing gas introduction pipe from the second stage processing gas introduction pipe to the final stage processing gas introduction pipe. An automatic valve is installed in each stage's processing gas introduction pipe,
These automatic valves are configured to be opened and closed by signals from the pressure detector of the processing gas introduction pipe in the preceding stage, and a bypass line is provided from the inlet side to the outlet side of each automatic valve, and a water sealing device is installed in this bypass line. A ground flare system characterized by intervening.