Process design and simulation of gasification and Fischer-Tropsch process for biofuels production from lignocellulosic biomass
Author
Mencigar, Matevz
Term
4. term
Education
Publication year
2020
Submitted on
2020-06-04
Pages
94
Abstract
Denne afhandling bruger computersimuleringer i Aspen Plus (software til procesmodellering) til at undersøge, hvordan biomasse kan omdannes til flydende brændstoffer via forgassing og Fischer–Tropsch (FT)-syntese. Forgassing omdanner biomasse til syntesegas (en blanding af brint og kulmonoxid), og FT-syntese bruger en katalysator til at omdanne denne gas til kulbrinter. Tre procesopstillinger blev simuleret: én med højtemperatur-FT og to med lavtemperatur-FT, hvor den ene brugte en jernbaseret katalysator og den anden en koboltbaseret katalysator. Fordi temperatur og katalysator påvirker, hvilke produkter der dannes, gav processerne forskellige slutprodukter med fokus på diesel- og benzinlignende biobrændstoffer samt metan. Herefter blev processerne økonomisk vurderet og sammenlignet. Lavtemperatur-FT med en koboltbaseret katalysator klarede sig bedst. Til sidst blev design og drift af to centrale separationsenheder—hoveddestillationskolonnen og fraktioneringskolonnen—optimeret for kobolt-varianten for at forbedre ydeevnen. Denne optimering reducerede de estimerede udstyrsomkostninger med 175.000 $.
This thesis uses computer simulations in Aspen Plus (process modeling software) to study how biomass can be turned into liquid fuels via gasification and Fischer–Tropsch (FT) synthesis. Gasification converts biomass into synthesis gas (a mix of hydrogen and carbon monoxide), and FT uses a catalyst to turn this gas into hydrocarbons. Three process setups were simulated: one with high-temperature FT and two with low-temperature FT, using either an iron-based catalyst or a cobalt-based catalyst. Because temperature and catalyst change the product distribution, the routes produced different final product slates, focusing on diesel- and gasoline-like biofuels as well as methane. The processes were then economically evaluated and compared. Low-temperature FT with a cobalt-based catalyst performed best overall. Finally, the design and operation of two key separation units—the main distillation column and the fractional distillation column—were optimized for the cobalt-based case to improve performance, reducing estimated equipment costs by $175,000.
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