Kinetic modeling of polymer-grade ethylene production by diluted ethanol dehydration over H-ZSM-5 for industrial design. Issue 5 (October 2018)

• Record Type: Journal Article
• Authors: Becerra, Jorge; Quiroga, Eliana; Tello, Edisson; Figueredo, Manuel; Cobo, Martha
• Is Part Of: Journal of environmental chemical engineering. Volume 6:Issue 5(2018)
• Page Start: 6165
• Page End: 6174
• Publication Date: 2018-10
• Subjects: Bioeconomy -- Biorefinery -- Capital expenses -- Operation expenses -- Light olefins; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2018.09.035
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: Ethylene production from bioethanol dehydration was studied over H-ZSM-5. In-situ DRIFTS was employed to evaluate the ethanol adsorption over H-ZSM-5. A Langmuir-Hinshelwood kinetic expression of the reaction was developed. A plant producing 99.9 mol% ethylene was proposed with a cost of 338 USD/ton-year. Abstract: The production of ethylene from bioethanol dehydration is considered one of the most promising processes for industry. In this work, H-ZSM-5 zeolites with different Si/Al ratios (Si/Al = 23, 30, and 280) were evaluated as catalysts during diluted bioethanol dehydration. In situ DRIFTS ethanol adsorption experiments showed that ethanol is adsorbed on both the SiOHAl Brønsted acid sites and SiOH silanol Lewis species, preferentially over the latter in the HZSM-5 with a Si/Al of 280 at temperatures lower than 300 °C. This process likely leads to the formation of CO ethoxy species, which are further turned into ethylene. Activity tests showed total conversion of ethanol and selectivity of 99% to ethylene using a H-ZSM-5 with a Si/Al = 280 at 300 °C and a space velocity (W/F) of 0.72 gcat h gEtOH −1 . This ethylene production was maintained during 72 h of time on stream (TOS). A Langmuir-Hinshelwood-based kinetic expression was proposed for the diluted ethanol dehydration in the range of 200–300 °C using H-ZSM-5 with a Si/Al ratio of 280. This reactor equation was used to propose a conceptual design of an industrial plant for producing polymer-grade ethylene from diluted bioethanol. Capex of 1 million USD (72 USD/ton-year ethylene) and Opex of 4.7 million USD/year (338 USD/ton-year) were calculated for a plant that produces 13.9 Mton year −1 ethylene from bioethanol. These costs are comparable to those from the oil industry (Capex of 1100 USD/ton-year and Opex of 324 UDS/ton-year), showing the large opportunity for sustainable production of ethylene from bioethanol.