Thermomechanically integrated distillation of ethylene from ethane
- Univ. of Missouri, Rolla, MO (United States)
The separation of ethylene from ethane by distillation is normally the final step in the production of ethylene. The critical temperature of ethylene is about 50 F, therefore moderately low temperatures and moderately high pressures are typically used to provide optimum economic conditions. The optimum design can require thick walled and heavy pressure vessels which may be constructed of expensive alloy steels depending on the specific operating conditions. The required purity of ethylene usually exceeds 99.9%, and the economic level of recovery is approximately 99%. In addition, the relative volatility of ethylene to ethane is moderately small ranging from about 1.13 for high pressure mixtures rich in ethylene to 2.34 for low pressure mixtures rich in ethane. The relatively high purity and recovery and relatively low relative volatility dictate a large distillation column with more than 100 trays and a large diameter for world scale production levels of over a billion pounds per year of ethylene. The installed capital cost for a unit of this type and size can exceed twenty million dollars, and utility costs can exceed one million dollars per year. Consequently, there is a strong economic incentive to reduce costs through improved process designs for the distillation of ethylene from ethane, and the process is well studied in the literature. Thermomechanically integrated distillation provides an improved design which can reduce both capital and operating costs as compared to the best conventional designs. In this paper, the conventional designs for both vapor and liquid feeds are reviewed, the underlying thermodynamics characterizing the process is discussed, alternative thermomechanically integrated designs are presented, and utility and purchased equipment costs are compared.
- OSTI ID:
- 288696
- Report Number(s):
- CONF-9404309-; TRN: IM9639%%405
- Resource Relation:
- Conference: 6. ethylene producers conference, Atlanta, GA (United States), 17-21 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of 6. ethylene producers` conference: Proceedings. Volume 3; PB: 721 p.
- Country of Publication:
- United States
- Language:
- English
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