Analysis of design and operation of multi-point ground flares

Multi-point ground flares (MPGF) are used to process large quantities of hydrocarbon gases
generated in chemical processing or petrochemical refining. These flares use hundreds of flare
burners arranged and fired in a staged fashion. A wind fence surrounds the MPGF to shield the
flames from plant operators and neighboring communities reduce the impact of ambient wind on
the flames to promote highly efficient combustion (see Figure 1). Safety concerns related to
radiation flux, ignition cross lighting, and excessive emissions have been examined using
Computational Fluid Dynamics (CFD) [1]. This paper will discuss recent work aimed at
understanding how burner and row spacing impact radiation flux and respective ground and
fence temperature plus flame shape and height. Based on previous work, design guidelines and
operating limits are being developed addressing:
- Flame height, shape and smokeless performance based on tip spacing and row spacing,
- Wind fence porosity and its impact on flame height and soot production,
- Tip port area and tip spacing effect on predicted radiation flux surrounding surfaces,
- Tip size effect on flare DRE and ignition, and
- Radiation flux outside of the wind fence.
Previous work on MPGF design and operation supporting these conclusions is discussed.
Figure 1 – General Multi-Point Ground Flare (MPGF) with tips and wind fence design