In refining energy considerations, distillation is typically responsible for what fraction of total energy?

In refining energy considerations, distillation is typically responsible for what fraction of total energy?

• A. 10%
• B. 40%
• C. 60%
• D. 80%

Answer: (B)

Distillation uses a lot of energy because it has to vaporize and then condense large streams of hydrocarbons to achieve the required separations. The reboilers provide the heat to keep columns duty-ing, while the condensers and overheads must be cooled and condensed, and reflux is recycled to drive the separation. Because many refinery streams require several distillation steps and operate with relatively low relative volatilities between components, the energy tied up in heating and cooling the distillation system tends to be a major share of total process energy. In typical refinery energy balances, distillation is recognized as a substantial portion of total energy use, often described as a sizable fraction, with the rest consumed by furnaces, upgrading units, pumps, compressors, and utilities.

Distillation uses a lot of energy because it has to vaporize and then condense large streams of hydrocarbons to achieve the required separations. The reboilers provide the heat to keep columns duty-ing, while the condensers and overheads must be cooled and condensed, and reflux is recycled to drive the separation. Because many refinery streams require several distillation steps and operate with relatively low relative volatilities between components, the energy tied up in heating and cooling the distillation system tends to be a major share of total process energy. In typical refinery energy balances, distillation is recognized as a substantial portion of total energy use, often described as a sizable fraction, with the rest consumed by furnaces, upgrading units, pumps, compressors, and utilities.