Construction method and structure for isolating combustible gas risk in a duct

Abstract

The application discloses a construction method for isolating combustible gas risk in a pipeline and a structure thereof, and comprises the following steps: screening a blocked pipeline with hidden safety hazards on both sides of a construction position; customizing a flange blockage device according to the specification of the blocked pipeline at the construction position; sealing the pipeline on both sides of the construction position by the blockage device; reforming the pipeline passing through the construction position into a detection gas pipeline with safety gas; providing an inlet of safety gas at one end of the detection gas pipeline and connecting a gas discharge port of the pipeline at the other end for discharging the safety gas; continuously injecting the safety gas into the detection gas pipeline and keeping the gas in the detection gas pipeline in a slightly positive pressure state, meanwhile, opening a vent valve of the gas discharge port and detecting the safety gas concentration in real time at the position; judging the safety of the construction position according to the concentration standard value of the safety gas. In the case that there is no internal leakage of the valve or there is internal leakage of the valve, the safety hidden danger caused by production suspension, maintenance and modification can be solved by the isolation method.

Description

Technical Field

[0001] This invention relates to the technical fields of LNG receiving terminals, offshore oil fields, and onshore terminals, and in particular to safe construction methods and structures for valves that may have internal leakage during maintenance, renovation, and shutdown repairs of the aforementioned LNG receiving terminals, offshore oil fields, and onshore terminals. Background Technology

[0002] LNG receiving terminals, offshore oil fields, and onshore terminals undergo annual shutdowns for maintenance and frequently require process modifications. Before commencing any of these tasks, the processes must be isolated to ensure safety during shutdowns, maintenance, or modifications. Internal and micro-leaks in valves are common issues in these processes, especially those involved in oil and gas operations. The presence of internal and micro-leaks poses significant safety hazards during shutdowns, maintenance, and modifications. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a construction method and structure for isolating the risk of flammable gases in pipelines. Regardless of whether there is internal leakage in the valve, the isolation method solves the problem of the great safety hazards caused by shutdown, maintenance and renovation.

[0004] To address the aforementioned technical problems, this invention provides a construction method for isolating the risk of flammable gases within pipelines, comprising the following steps:

[0005] S1: Select pipes with safety hazards on both sides of the construction site for sealing;

[0006] S2: Customize flange plugs according to the specifications of the pipe to be plugged at the construction location;

[0007] S3: The flange plug will seal the pipelines on both sides of the construction location;

[0008] S4: Modify the pipelines at each of the construction locations along the route into detection gas pipelines carrying safety gas;

[0009] S5: A safety gas inlet is provided at one end of the detection gas pipeline, and the other end is connected to the pipeline vent for discharging the safety gas.

[0010] S6: Continuously inject safety gas into the detection gas pipeline and maintain the gas in the detection gas pipeline at a slightly positive pressure. At the same time, open the vent valve of the vent port and detect the safety gas concentration at this location in real time.

[0011] S7: Determine the safety of the construction site based on the standard concentration value of the safety gas.

[0012] Furthermore, the safety gas is an inert gas.

[0013] Further, the inert gas is nitrogen.

[0014] Further, the detection gas pipeline is modified by using the pipeline inherent to the construction site.

[0015] Another technical solution of the present application is a construction method for isolating the risk of combustible gas in a pipeline, characterized in that a flange blockage device is arranged on the pipeline on both sides of the construction position, the flange blockage device seals the pipeline on both sides of the construction position, a detection gas pipeline through which safety gas passes is modified on each pipeline passing through the construction position, one end of the detection gas pipeline is provided with an inlet of safety gas, and the other end is connected to a gas discharge port of a safety gas pipeline.

[0016] Further, the inlet and the gas discharge port of the safety gas are arranged at positions on the upstream and downstream sides of the construction site.

[0017] The technical effect of the present application is that the combustible gas concentration is detected in real time, inert gas nitrogen is filled near the valve with internal leakage, the distal end is opened for venting, the inert gas is used to discharge the dangerous medium leaked or remaining in the construction area, and four protection measures are used to ensure the safety of construction. At the same time, the present application uses the existing pipeline for partial replacement, only part of the pipeline is replaced, the replacement of the entire pipeline and equipment is avoided, and the efficiency of on-site replacement is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of a construction structure for isolating the risk of combustible gas in a pipeline. DETAILED DESCRIPTION

[0019] The present application will be further described below in combination with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting the present application.

[0020] As shown in Figure 1 , the present application is a construction method for isolating the risk of combustible gas in a pipeline, which comprises the following steps:

[0021] S1: screening the blockage pipeline with safety hazards on both sides of the construction position;

[0022] S2: customizing the flange blockage device 2 according to the specifications of the blockage pipeline of the construction position;

[0023] S3: the flange blockage device 2 seals the pipeline on both sides of the construction position;

[0024] S4: The pipeline at each construction site is modified to a detection gas pipeline with safety gas, pipeline 1 and pipeline 2 shown in the figure; the detection gas pipeline is modified by using the pipeline inherent to the construction site, without the need to establish a new pipeline, avoiding replacement of the entire pipeline and equipment, and greatly improving the efficiency of site replacement.

[0025] S5: The detection gas pipeline has a safety gas inlet 3 at one end and a gas vent (11 / 12) connected to the pipeline at the other end for discharging safety gas;

[0026] S6: Safety gas is continuously injected into the detection gas pipeline (pipeline 1 and pipeline 2), and the gas in the detection gas pipeline is kept at a slight positive pressure, while the vent valve is opened and the safety gas concentration is detected in real time at this point; the safety gas is an inert gas, and in this embodiment, the inert gas is nitrogen.

[0027] S7: Determine the safety of the construction site according to the standard value of the safety gas concentration.

[0028] As Figure 1 shown, it is a construction structure for isolating the risk of flammable gas in the pipeline according to the present application, and in this embodiment, the center site is a welding bead, the valve 5 is close to the welding bead, and the flange blockage device 2 is provided on the pipeline on both sides of the construction site. The flange blockage device 2 seals the pipeline on both sides of the construction site, and a flange blockage device 2 is installed between the upstream flange weld position and the butterfly valve to prevent residual flammable gas from entering the welding area; a flange blockage device 2 is also installed at the corresponding position on the downstream side to isolate the pipe blockage.

[0029] The pipeline at each construction site is modified to a detection gas pipeline with safety gas, as shown in pipeline 1 and pipeline 2, in fact, the number of detection gas pipelines similar to pipeline 1 and pipeline 2 should not be exhaustive. One end of the detection gas pipeline is provided with a safety gas inlet 3, and the other end is connected to a gas vent (11 / 12) for discharging safety gas. The safety gas inlet and the gas vent are located at the upstream and downstream positions of the construction site.

[0030] In actual work, the staff detects the flammable gas concentration in real time, fills the inert gas nitrogen near the possible internal leakage valve 5, opens the vent at the far end, uses the inert gas to discharge the internal leakage or residual hazardous medium away from the construction area, and then uses the flange blockage device mechanical blockage, on-site monitoring method, four protection measures to ensure construction safety.

[0031] The above-described embodiments are merely preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitutions or transformations made by those skilled in the art based on the present application are within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A construction method for isolating the risk of flammable gases inside a pipeline, characterized in that, The method includes the following steps: S1: Select pipes with safety hazards on both sides of the construction site for sealing; S2: Customize flange plugs according to the specifications of the pipe to be plugged at the construction location; S3: The flange plug will seal the pipelines on both sides of the construction location; S4: The pipelines at each of the construction locations are modified into detection gas pipelines carrying safety gas, and the detection gas pipelines are modified from the existing pipelines at the construction site. S5: A safety gas inlet is provided at one end of the detection gas pipeline, and a vent is connected to the other end of the pipeline for discharging the safety gas. The safety gas inlet and vent are located on the upstream and downstream sides of the construction site, respectively. S6: Continuously inject safety gas into the detection gas pipeline and maintain the gas in the detection gas pipeline at a slightly positive pressure. At the same time, open the vent valve of the vent port and detect the safety gas concentration at this location in real time. S7: Determine the safety of the construction site based on the standard concentration value of the safety gas.

2. The construction method for isolating the risk of flammable gases in a pipeline according to claim 1, characterized in that, The safety gas is an inert gas.

3. The construction method for isolating the risk of flammable gases in a pipeline according to claim 2, characterized in that, The inert gas is nitrogen.

4. The structure of the construction method for isolating the risk of flammable gases in a pipeline according to any one of claims 1 to 3, characterized in that, Flange plugs are installed on the pipelines on both sides of the construction site to seal the pipelines on both sides of the construction site. Each pipeline passing through the construction site is modified into a detection gas pipeline carrying safety gas. One end of the detection gas pipeline is equipped with a safety gas inlet, and the other end is connected to a vent for discharging the safety gas. The safety gas inlet and vent are located on the upstream and downstream sides of the construction site, respectively.

Images