Heat integrated ethanol dehydration flowsheets

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Separation Science and Technology

DOI:https://doi.org/10.1080/01496399508010381· OSTI ID:88715

Hutahaean, L S; Shen, W H; Brunt, V Van ^[1]

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1. Univ. of South Carolina, Columbia, SC (United States)

zA theoretical evaluation of heat-integrated heterogeneous-azeotropic ethanol-water distillation flowsheets is presented. Simulations of two column flowsheets using several different hydrocarbon entrainers reveal a region of potential heat integration and substantial reduction in operating energy. In this paper, methods for comparing hydrocarbon entrainers are shown. Two aspects of entrainers are related to operating and capital costs. The binary azeotropic composition of the entrainer-ethanol mixture is related to the energy requirements of the flowsheet. A temperature difference in the azeotrophic column is related to the size of the column and overall process staging requirements. Although the hydrophobicity of an entrainer is essential for specification of staging in the dehydration column, no substantial increase in operating energy results from an entrainer that has a higher water content. Likewise, liquid-liquid equilibria between several entrainer-ethanol-water mixtures have no substantial effect on either staging or operation. Rather, increasing the alcohol content of the entrainer-ethanol azeotrope limits its recovery in the dehydration column, and increases the recycle and reflux streams. These effects both contribute to increasing the separation energy requirements and reducing the region of potential heat integration. A cost comparison with a multieffect extractive distillation flowsheet reveals that the costs are comparable; however, the extractive distillation flowsheet is more cost effective as operating costs increase.

• OSTI ID: 88715
• Report Number(s): CONF-931043--
• Journal Information: Separation Science and Technology, Journal Name: Separation Science and Technology Journal Issue: 7-9 Vol. 30; ISSN 0149-6395; ISSN SSTEDS
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
40 CHEMISTRY
AZEOTROPE
COST
DEHYDRATION
DISTILLATION
ETHANOL
MATHEMATICAL MODELS