Petrochemical Furnaces

REI provides research and consulting services to the chemical process industry. REI has modeled a variety of combustion systems in the petrochemical industry, generally with a goal of enhancing product yield and improving furnace thermal efficiency. One area of particular interest is interaction between burner performance and process efficiency in pyrolysis furnaces. REI is working with industry leaders Stone & Webster and John Zink to develop improved modeling capabilities in this area.

Experience with petrochemcial furnaces and related systems includes:

  • Ethylene Cracking Furnaces
    • Flow pass balancing
    • Decoking
  • Xylene Reboiler
  • Continuous Catalyst Regenerator
  • Thermal Oxidizers
  • Gas and Oil Burners
  • Flares

Typical project objectives include improving performance in the following areas:

  • Pollutant Formation
  • Waste Stream Disposal
  • Flame Impingement
  • Tube Overheating
  • Flux & COT Uniformity
  • Yield & Conversion
  • Radiant Efficiency

In addition to the applications listed here, REI continues to develop expertise in new areas. If your application is not among those listed, please contact us to discuss appropriate ways we may be able to work together.

Ethylene Furnace – Flow Pass Balancing

REI’s turbulent reacting flow code BANFF was used to simulate flow and heat transfer in a full-scale “M” coil ethylene cracking furnace. Full two-way coupling between the “fire-side” and “process-side”computations provided accurate estimation of process conditions, including process temperature as a function of tube length. The simulation indicated the presence of a “cool end wall” which contributed to a non-uniform coil outlet temperature distribution under uniform firing conditions. Simulations demonstrated the feasibility of using flow pass balancing, in which the process flow rates in pairwise coils are independently adjusted and controlled, to achieve more uniform distributions of coil outlet temperature.

Ethylene_Furnace_Flow_Balance

 

Cracking Furnace – Decoking Operation

REI’s two phase, turbulent reacting flow code GLACIER was used to simulate flow, heat transfer, and particle burnout within a “U coil” ethylene cracking furnace during decoke firing conditions. Process-side conditions were computed based on calculation of the fire-side flow field and heat transfer properties. The process of “in-furnace decoking,” in which the partially oxidized coke with carrier steam and air from the process coils is re-routed back into the firebox for burnout was modeled. Effects of decoke nozzle size, nozzle position, and coke particle size were examined to optimize coke particle trajectories and burnout within the firebox.

Decoking_Operation

 

Xylene Reboiler

The REI combustion simulation code BANFF was used to simulate combustion and heat transfer in a xylene reboiler. Convective and radiative heat transfer to individual process tubes was computed as a function of tube length and position within the heater. Results were used to identify tube “hot spots” and to identify the physics behind observed temperature profiles in the radiant and convective sections of the heater. Parametric simulations were used to study the effects of fuel changes and excess air variations on heat transfer and gas exit temperature.

Xylene_Reboiler

Continuous Catalyst Regenerator

Continuous_Catalyst_RegeneratorThe REI combustion simulation code BANFF was used to simulate combustion and heat transfer in a multi-chamber process heater used in a continuous catalyst regenerator. Convective and radiative heat transfer to individual process tubes was computed as a function of tube length and position within the heater. Process temperatures at the tube exits were also computed to assess tube-to-tube and heater section-to-section variations. Parametric studies were used to evaluate the effects of load balancing and fuel heating value changes for the 50 burners along the floor of the heater.