Fractionation of natural gas liquids (NGLs) is a complicated process that requires significant engineering skill. Thankfully, the technological age has brought with it tools to more efficiently test fractionation unit designs: process simulators. During the initial design phase for a new fractionation unit, for example, the best operational configuration may not be apparent even after being given a specific set of requirements. Being told what constituents must be processed as well as the necessary purities and volumes definitely will narrow down design options; however, several unknowns may still exist, requiring the use of simulation technology.

Process simulators allow users to select simulator components (including the number of columns), fluid packages, streams and draws, and heating and subcooling components to test a wide variety of designs. Additional parameters such as component purities, ratios, and rates; reboiler and condenser temperatures; reflux flow rates; and water content and solubility can be adjusted. This allows users to evaluate distillation column efficiency, improve process control strategies, measure reboiler and overhead condenser efficiency, gauge system throughput capacity, and determine how to meet required product purity. The end result of fractionation unit simulation includes benefits such as improved product quality, reduced energy consumption, and better returns on investment.

Process simulation, however, can be used for more than new builds. Existing fractionation structures, owned or newly acquired, often need to be optimized or converted to process hydrocarbons in a new way or to process entirely different hydrocarbons. Data related to the existing structure and its past use — including 3D laser scans of the fractionation facility — can be pulled into simulation software for further analysis. In addition to testing different brownfield modifications, the operating conditions of existing equipment can be verified as meeting predicted operating conditions as determined by the simulator.

Finally, process simulation makes a useful educational tool for aspiring and existing engineers. Goals can be defined for undergraduate and graduate courses that include process simulation as a means to meeting those goals. Likewise, continuing education courses can be specifically designed so that existing engineers can expand their knowledge base working with fractionation simulation tools like Apen Plus, HYSYS, or Matlab.