Engineering

CFD application to process equipment Design

A typical chemical processing unit processes a large amount of fluid. Given the economics of most unit operations, even small improvements in efficiency and performance can result in significant increase and saving in costs. Computational methods provide a viable tool for analysis and trouble shooting of such equipment.

A typical chemical process plant involves fluid flow devices such as pipes and valves. Fluid transport equipment such as pumps, compressors are employed for moving fluid from one unit operation to another. Dynamic and static mixing equipment are at the heart of most chemical processing plants. Heat generation and heat evaporators, condensers are employed for generating and transferring heat essential for various processes. Separation equipment such as cyclones, electro-static precipitators, hydro-cyclones, centrifuge separators, gravity separators are employed for gas-solid separators, gas-liquid separators and liquid-solid separation. Failure of a chemical process equipment can result in undesirable down-time and loss of revenue. Computational fluid dynamics (CFD) methods can be applied to examine different equipment designs, or compare performance under different operating conditions.

Computational Fluid DynamicsComputational fluid dynamics (CFD) methods are based on fist principles of mass, momentum and energy conservation. CFD methods involve the solution of conservation equations for mass, momentum and energy at thousands of locations within the flow domain. The details of the computed solution provides flow variables flow variables such as velocity, pressure, temperature, density, concentration, etc. at thousands of locations within the domain.

Computational Fluid Dynamics application to process equipment design






Illustration of Typical Roles which CFD can Play

Process Equipment

Impact of CFD

Mixing: Stirred tank reactors, static mixers, jet mixers, emulsification units.

  • Examine performance of static mixers.
  • Optimize stirred tank performance.
  • Predict share distribution in stirred tank reactor.
  • Scale-up/scale-down of reactors.

Fluid Transport devices: Pumps, compressors, manifolds, headers, valves, flow distributors.

  • Establish envelope of performance.
  • Ensure uniform flow distribution.
  • Minimize power requirements.
  • Identify and eliminate sources of erosion in transport of slurry.

Separation Units: Cyclones, scrubbers, precipitators, centrifuges, gravity separators.

  • Optimize and predict performance.
  • Take a ‘look-inside’ the process.
  • Evaluate design concepts.

Heat generation and heat transfer: Heat exchangers, boilers, furnaces, process heaters, burners.

  • Minimize failure of heat-exchanges.
  • Control formation of pollutants.
  • Eliminate hot-spots in heaters.
  • Improve flame stability and burner efficiency.
  • Improved heat-recovery.

Reactors: Packed bed, bubble column, fluidized bed.

  • Improved catalyst utilization.
  • Minimize waste.
  • Reduced operating costs.

Auxiliary processes: Filling, packing.

  • Eliminate plugging, sloshing, spilling.