Functions

  • Emission and Combustion of Waste Gases
    In industries like petroleum and chemical engineering, a large amount of waste gases are generated during the production process. The risers and stacks of the flare system collect these waste gases, guide them to high altitudes, and safely combust and discharge them, preventing direct release into the atmosphere and avoiding environmental pollution and safety hazards.
  • Prevention of Flashback
    Through reasonable design and installation, the risers and stacks of the flare system can effectively prevent flames from flashback into process units, avoiding serious safety accidents such as explosions and ensuring the safe operation of production units.

Types

  • Self-Supported
    • Structural Features
      Composed of multiple cylindrical sections with different diameters, the self-supported riser is usually larger in diameter at the bottom and smaller at the top, requiring only one foundation and occupying a relatively small area.
    • Advantages and Disadvantages
      Advantages: No guy wires are needed, resulting in low maintenance costs, and there are no design or maintenance issues caused by guy wires.
      Disadvantages: The height is usually limited, affected by transportation conditions and on-site manufacturing economy.
    • Application Scenarios
      Suitable for occasions with low height requirements and limited site space.
  • Guyed
    • Structural Features
      The top of the flare riser is supported by a set of steel cables (guy wires), which are generally arranged at 120-degree angles and require multiple anchor foundations to fix the guy wires on the ground.
    • Advantages and Disadvantages
      Advantages: It can achieve a higher height with relatively low cost.
      Disadvantages: It requires a large area to set up anchors, and the maintenance and inspection of guy wires are complex.
    • Application Scenarios
      Suitable for situations where a higher flare height is needed and the site space is open.
  • Derrick
    • Structural Features
      The riser is supported by a steel truss structure (derrick), generally requiring three to four foundations for the derrick legs.
    • Advantages and Disadvantages
      Advantages: It can eliminate concerns about process temperature design, and a single derrick structure can support multiple flare risers.
      Disadvantages: The foundation construction cost is relatively high.
    • Application Scenarios
      Suitable for occasions where multiple flare risers need to be supported and high requirements for process temperature control exist.
  • Demountable Derrick
    • Structural Features
      Based on the derrick type, it adds detachable and mobile functions. Through devices such as a winch system, guide rails, tilting platforms, and flanged riser sections, the flare tip can be lowered to the ground for maintenance, inspection, or repair.
    • Advantages and Disadvantages
      Advantages: Maintenance can be carried out without shutting down the flare system, avoiding impacts on production caused by flare system shutdown, and reducing the use of leased equipment such as large cranes.
      Disadvantages: The structure is relatively complex, and the initial investment cost is high.
    • Application Scenarios
      Suitable for industrial facilities with high requirements for the operational continuity of the flare system and frequent maintenance.

Design Considerations

  • Gas Flow and Composition
    Accurately determine parameters such as the flow rate, composition, temperature, and pressure of the waste gases to be treated, so as to select appropriate riser diameters and stack heights, ensuring smooth emission and complete combustion of waste gases.
  • Environmental Conditions
    Including local wind speed, wind direction, seismic intensity, temperature variation range, etc. For example, in high-wind-speed areas, the structural design of risers and stacks needs to be strengthened to ensure their stability.
  • Safety Distance
    Adequate safety distances must be maintained between the flare system risers/stacks and surrounding buildings, process units, roads, etc., to prevent accidents such as fires and explosions from endangering surrounding facilities and personnel.
flare riser/flare stack