Torch fuel gas undisturbed switching device

Abstract

The utility model provides a torch fuel gas undisturbed switching device. Comprising a first adjusting valve group on a first fuel gas pipeline main line, a first bypass valve on a first fuel gas pipeline branch line, a second adjusting valve group on a second fuel gas pipeline main line, a second bypass valve on a second fuel gas pipeline branch line and a rotor flow meter FT on a main pipeline. The first bypass valve group comprises a first hand valve, a first drain valve and a pressure valve PV; and the second bypass valve group comprises a second hand valve, a second drain valve and a flow valve FV. The remote transmission pressure gauge PT, the pressure valve PV, the flow valve FV and the rotor flow meter FT are connected into a DCS centralized and decentralized control system, dynamic monitoring of torch fuel gas is achieved, manual gas source switching is changed into automatic gas source switching, an operator can complete control without being on site, and convenience, rapidness and accuracy of operation are achieved. And meanwhile, the gas pressure of the two pipelines is more stable, and the operation safety of the chemical device is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical torches, in particular to a flare fuel gas non-disturbance switching device. Background Art

[0002] Chemical plants use flare systems to centrally combust harmful gases from production, converting them into carbon dioxide, water, or other low-toxic substances with minimal impact on the environment and human health. As a critical safety feature, chemical flares ensure safe emissions from production systems and constitute the last line of defense for environmental and personnel safety.

[0003] During normal operation of the flare, a pilot light must be kept burning continuously. Its function is to quickly ignite the combustible gas discharged from the flare system when needed. The fuel gas sources of the pilot light in the synthetic ammonia unit are generally natural gas and liquid nitrogen wash tail gas. The two gases are stored in two separate pipelines, which are connected to the main pipeline in parallel. Manual valves are respectively provided on the two pipelines. Under corresponding circumstances, the switches of the manual valves on the two pipelines are manipulated to allow the appropriate gas to enter the main pipeline. Normally, only liquid nitrogen wash tail gas enters the main pipeline and is transported to the flare. Natural gas is an external gas and due to its high price, it is generally only used in the following situations when it enters the main pipeline: first, when no liquid nitrogen wash tail gas enters the main pipeline during the start-up and shutdown stages of the unit; second, when the flare is operating abnormally or the liquid nitrogen wash tail gas supply is abnormal.

[0004] Currently, before switching the flare fuel gas, the flare gas consumption must be manually calculated based on the pressure gauge on the Claus sulfur recovery unit's user end and the flow meter readings at the source public gas station. The manual switching is then performed by manually adjusting the manual valves on the two flare gas supply pipelines. This operation is relatively complex and cannot achieve disturbance-free adjustment and switching. The stable operation of related equipment is frequently interfered with by human factors, which has a significant impact on the stable operation of the flare and related fuel gas user equipment, and in severe cases, causes some processes to shut down. Furthermore, due to the different pressures of the two fuel gases (0.24 MPa for natural gas and 0.4 MPa for fuel gas), the pressures of the two air inlet pipelines cross-channel during the fuel gas switching, resulting in large pressure fluctuations. This is detrimental to the safe operation of related equipment, thereby affecting the safe emissions of the entire chemical plant and adversely affecting the company's environmental protection. Utility Model Content

[0005] In view of the problem that manual switching of torch fuel gas in the prior art is complicated to operate and easily interfered by various factors, the utility model provides a disturbance-free switching device for torch fuel gas, comprising: a first fuel gas pipeline main line, a first fuel gas pipeline branch line, a second fuel gas pipeline main line, a second fuel gas pipeline branch line and a main pipeline; the first fuel gas pipeline branch line is a pipeline connected in parallel with the first fuel gas pipeline main line, and the second fuel gas pipeline branch line is a pipeline connected in parallel with the second fuel gas pipeline main line; the first fuel gas pipeline main line and the second fuel gas pipeline main line are connected to the main pipeline after being connected in parallel; the inlet end of the first fuel gas pipeline main line is connected to natural gas, and the inlet end of the second fuel gas pipeline main line is connected to liquid nitrogen to wash tail gas; the first fuel gas pipeline main line is sequentially arranged along the air inlet direction There is a remote pressure gauge PT, a first regulating valve group and a check valve; a first bypass valve is arranged on the first fuel gas pipeline branch line; the first regulating valve group includes a first manual valve, a first shower valve and a pressure valve PV; the remote pressure gauge PT, the second regulating valve group and the check valve are arranged in sequence along the air intake direction on the second fuel gas pipeline main line; a second bypass valve is arranged on the second fuel gas pipeline branch line; the second regulating valve group includes a second manual valve, a second shower valve and a flow valve FV; a rotor flowmeter FT is arranged on the main pipeline; the signal PIA of the remote pressure gauge PT and the signal FIA of the rotor flowmeter FT are transmitted to the DCS centralized distributed control system, and the control signal PC of the pressure valve PV and the control signal FC of the flow valve FV come from the DCS centralized distributed control system.

[0006] Furthermore, the check valve is arranged near the main pipeline.

[0007] Furthermore, there are two first manual valves, which are respectively located in front of and behind the pressure valve PV.

[0008] Furthermore, the first shower valve is arranged between the two first manual valves.

[0009] Furthermore, there are two second manual valves, which are respectively located in front of and behind the flow valve FV.

[0010] Furthermore, the second shower guide valve is arranged between the two second hand valves.

[0011] Compared with the prior art, this utility model has the following beneficial effects:

[0012] This utility model provides a disturbance-free switching device for flare fuel gas. By connecting a remote pressure gauge (PT), pressure valve (PV), flow valve (FV), and rotor flowmeter (FT) to a DCS centralized distributed control system, it enables dynamic monitoring of flare fuel gas and automatically switches the gas source from manual to automatic, eliminating the need for on-site operator control. This facilitates convenient, rapid, and accurate operation. Furthermore, the gas pressure in both pipelines is more stable, improving the safety of chemical plant operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a flare fuel gas disturbance-free switching device structure according to an embodiment of the utility model;

[0014] In the figure: 1. First fuel gas pipeline main line; 2. Second fuel gas pipeline main line; 3. Main pipeline; 4. Remote pressure gauge PT; 5. First fuel gas pipeline branch line; 6. Second fuel gas pipeline branch line; 7. Check valve; 8. First regulating valve group; 9. First bypass valve; 10. Second regulating valve group; 11. Second bypass valve; 12. First manual valve; 13. First shower valve; 14. Pressure valve PV; 15. Second manual valve; 16. Second shower valve; 17. Flow valve FV; 18. Rotor flowmeter FT. DETAILED DESCRIPTION

[0015] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0016] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. Terms such as "upper," "lower," "front," "back," "top," and "bottom" indicate positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or parts referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. It should be understood that the terms used in this manner are interchangeable, where appropriate, for the purposes of describing the embodiments of the present invention. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions.

[0017] The utility model provides a flare fuel gas non-disturbance switching device, such as Figure 1 As shown, it includes: a first fuel gas pipeline main line 1, a first fuel gas pipeline branch line 5, a second fuel gas pipeline main line 2, a second fuel gas pipeline branch line 6 and a main pipeline 3; the first fuel gas pipeline branch line 5 is a pipeline connected in parallel with the first fuel gas pipeline main line 1, and the second fuel gas pipeline branch line 6 is a pipeline connected in parallel with the second fuel gas pipeline main line 2; the first fuel gas pipeline main line 1 and the second fuel gas pipeline main line 2 are connected in parallel to the main pipeline 3; the inlet end of the first fuel gas pipeline main line 1 is connected to natural gas, and the inlet end of the second fuel gas pipeline main line 2 is connected to liquid nitrogen for washing tail gas; a remote pressure gauge PT 4, a first regulating valve group 8 and a check valve 7 are sequentially provided on the first fuel gas pipeline main line 1 along the air inlet direction; a first bypass valve 9 is provided on the first fuel gas pipeline branch line 5; the first regulating valve group 8 includes a first manual valve 12, a first pilot valve 13 and a pressure valve PV 14; a remote pressure gauge PT 4, second regulating valve group 10 and check valve 7; a second bypass valve 11 is provided on the second fuel gas pipeline branch line 6; the second regulating valve group 10 includes a second manual valve 15, a second pilot valve 16, and a flow valve FV 17; a rotor flowmeter FT 18 is provided on the main pipeline 3; the signal PIA from the remote pressure gauge PT 4 and the signal FIA from the rotor flowmeter FT 18 are transmitted to the DCS centralized distributed control system, and the control signal PC for the pressure valve PV 14 and the control signal FC for the flow valve FV 17 are from the DCS centralized distributed control system.

[0018] During equipment operation, remote pressure gauge PT 4 provides pressure indication and alarm (PIA) for the first and second fuel gas pipeline main lines 1 and 2, transmitting signals to the DCS centralized distributed control system. Rotameter FT 18 provides flow indication and alarm (FIA) for the main pipeline 3, transmitting signals to the DCS centralized distributed control system. Based on the PIA and FIA signal feedback, operators remotely control pressure valve PV 14 and flow valve FV 17 through the DCS centralized distributed control system, achieving precise regulation of pressure and flow in the first and second fuel gas pipeline main lines 1 and 2. To prevent crosstalk between the first and second fuel gas pipeline main lines 1 and 2 due to pressure differences when switching gas sources, check valves 7 are installed before the first and second fuel gas pipeline main lines 1 and 2 connect to the main pipeline 3.

[0019] Generally, the check valve 7 is arranged close to the main pipeline 3. In order to ensure the best effect of the check valve 7, the distance between the check valve 7 and the main pipeline 3 is as small as possible.

[0020] In this embodiment, natural gas is transported in the first fuel gas pipeline 1, and liquid nitrogen is transported in the second fuel gas pipeline 2 for tail gas scrubbing. During the equipment startup phase, the pressures in the first fuel gas pipeline 1 and the second fuel gas pipeline 2 are set to predetermined values ​​and maintained stable via the DCS. At this time, flow valve FV 17 on the second fuel gas pipeline 2 is closed, and the natural gas in the first fuel gas pipeline 1 is transported to the main pipeline 3 as the fuel gas source.

[0021] When switching the fuel gas from natural gas to liquid nitrogen-washed tail gas: if the pressure in the first fuel gas pipeline main line 1 fluctuates, the pressure valve PV14 controls the pressure in the first fuel gas pipeline main line 1 and stops the gas supply. The flow valve FV17 on the second fuel gas pipeline main line 2 opens and starts the gas supply, completing the fuel gas switch. If the pressure in the second fuel gas pipeline main line 2 fluctuates, the flow valve FV17 controls the pressure in the second fuel gas pipeline main line 2 and continues the gas supply from the first fuel gas pipeline main line 1. After the pressures in the two pipelines stabilize, the fuel gas switch is performed again until the switch is successful.

[0022] After the equipment enters the normal operation stage, the liquid nitrogen-washed tail gas in the second fuel gas pipeline main line 2 is continuously transported to the main pipeline 3, and the DCS centralized distributed control system monitors the pressure in the first fuel gas pipeline main line 1 and the second fuel gas pipeline main line 2, and the flow in the main pipeline 3. If the rotor flowmeter FT18 indicates that the flow in the main pipeline 3 is lower than the preset value, the pressure valve PV14 in the first fuel gas pipeline main line 1 is controlled to perform partial flow compensation.

[0023] In a preferred embodiment, corresponding devices are provided in the first and second regulating valve groups 8 and 10 to facilitate troubleshooting. Two first manual valves 12 are provided, one located before and one after the pressure valve PV 14. A first pilot valve 13 is provided between the two first manual valves 12. Two second manual valves 15 are provided, one located before and one after the flow valve FV 17. A second pilot valve 16 is provided between the two second manual valves 15.

[0024] During normal operation, the first manual valve 12 and the second manual valve 15 are open, while the first pilot valve 13, the first bypass valve 9, the second pilot valve 16, and the second bypass valve 11 are all closed. Both fuel gases are transported exclusively through the first fuel gas mainline 1 and the second fuel gas mainline 2. In the event of a malfunction in pressure valve PV 14 or flow valve FV 17, the manual valves preceding and following them are closed, isolating the pressure valve PV 14 or flow valve FV 17 for maintenance. The first bypass valve 9 or the second bypass valve 11 can be temporarily opened manually, allowing both fuel gases to be temporarily transported through the first fuel gas branch line 5 and the second fuel gas branch line 6. This ensures that even if a malfunction occurs in pressure valve PV 14 or flow valve FV 17, the flare gas supply is not affected. The first pilot valve 13 and the second pilot valve 16 are used to depressurize their respective pipelines and collect samples for analysis during troubleshooting. To facilitate removal, replacement, or maintenance, all valves are flange-connected.

Claims

1. A flare fuel gas disturbance-free switching device, characterized in that: include: A first fuel gas pipeline main line (1), a first fuel gas pipeline branch line (5), a second fuel gas pipeline main line (2), a second fuel gas pipeline branch line (6) and a main pipeline (3); the first fuel gas pipeline branch line (5) is a pipeline connected in parallel to the first fuel gas pipeline main line (1), and the second fuel gas pipeline branch line (6) is a pipeline connected in parallel to the second fuel gas pipeline main line (2); the first fuel gas pipeline main line (1) and the second fuel gas pipeline main line (2) are connected in parallel to the main pipeline (3); the inlet end of the first fuel gas pipeline main line (1) is connected to natural gas, and the inlet end of the second fuel gas pipeline main line (2) is connected to liquid nitrogen washing tail gas; a remote pressure gauge PT (4), a first regulating valve group (8) and a check valve (7) are sequentially arranged on the first fuel gas pipeline main line (1) along the air inlet direction; a first bypass valve (5) is arranged on the first fuel gas pipeline branch line Valve (9); the first regulating valve group (8) includes a first manual valve (12), a first pilot valve (13) and a pressure valve PV (14); the second fuel gas pipeline main line (2) is provided with the remote pressure gauge PT (4), the second regulating valve group (10) and the check valve (7) in sequence along the air inlet direction; the second fuel gas pipeline branch line (6) is provided with a second bypass valve (11); the second regulating valve group (10) includes a second manual valve (15), a second pilot valve (16) and a flow valve FV (17); a rotor flowmeter FT (18) is provided on the main pipeline (3); the signal PIA of the remote pressure gauge PT (4) and the signal FIA of the rotor flowmeter FT (18) are transmitted to the DCS centralized distributed control system, and the control signal PC of the pressure valve PV (14) and the control signal FC of the flow valve FV (17) are from the DCS centralized distributed control system.

2. The flare fuel gas disturbance-free switching device according to claim 1, characterized in that: The check valve (7) is arranged near the main pipeline (3).

3. The flare fuel gas disturbance-free switching device according to claim 1, characterized in that: There are two first manual valves (12) and they are respectively located in front of and behind the pressure valve PV (14).

4. The flare fuel gas disturbance-free switching device according to claim 1, characterized in that: The first shower valve (13) is arranged between the two first hand valves (12).

5. The flare fuel gas disturbance-free switching device according to claim 1, characterized in that: There are two second manual valves (15) and they are respectively located in front of and behind the flow valve FV (17).

6. The flare fuel gas disturbance-free switching device according to claim 1, characterized in that: The second shower guide valve (16) is arranged between the two second hand valves (15).

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