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Supercritical Carbon Dioxide Pretreatment of Various Lignocellulosic Biomasses

Narayana Swamy, Naveen
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1269524607

Abstract Details

2010, Master of Science (MS), Ohio University, Chemical Engineering (Engineering and Technology).
In the production of cellulosic ethanol, the pretreatment of biomass step is considered the most expensive and difficult part of the process. In Supercritical CO2 (SC-CO2) pretreatment method, CO2, which is considered a green solvent is used to treat the biomass. In this work corn stover, switchgrass and rye straw were pretreated using the SC-CO2 at various temperatures and pressures and subsequently enzyme hydrolyzed using the cellulase enzyme. The samples were analyzed for the presence of glucose. A typical CO2 to biomass ratio of 5/50 (g/g) was used in tests. Biomass samples were wetted with water prior to the SC-CO2 treatment. CO2 pressure was released as quickly as possible by opening a quick release value. For all pretreatments glucose yields from corn stover was higher than untreated samples (12mg/100mg biomass) and the maximum glucose yield (30mg/100mg biomass) was found at 3500psi and 150°C. These conditions were chosen for the pretreatment of various other biomasses. The maximum glucose yield for untreated switchgrass and rye straw were found to be 12mg/100mg biomass and 7.6mg/100mg biomass, respectively. The pretreated switchgrass (14mg/100mg of biomass) showed no improvement in the glucose yield as compared to an untreated sample. However, the pretreated corn stover (30mg/100mg biomass) and rye straw (13.5mg/100mg biomass) showed threefold and twofold increase, respectively. The SC-CO2 pretreatment with addition of catalysts such as H2SO4 and HCl was studied on rye straw. The addition of H2SO4 and HCl to the SC-CO2 pretreatment both improved the glucose yield as compared with the SC-CO2 pretreatment. The X-Ray diffraction result showed that there was no change in crystallinity of the SC-CO2 treated corn stover when compared to the untreated. SEM results showed the changes in surface morphology of the SC-CO2 treated corn stover when compared with untreated corn stover. This shows that the increase in glucose yield from enzyme hydrolysis for the SC-CO2 treated corn stover is due to increase in surface area. Carbonic acid (a weak acid) from dissolved CO2 in water phase may also contribute.
Tingyue Gu, PhD (Advisor)
Douglas Goetz, PhD (Committee Co-Chair)
Ahmed Faik, PhD (Committee Member)
Ben Stuart, PhD (Committee Member)
95 p.
Chemical Engineering
Supercritical; Carbon Dioxide; Pretreatment; Lignocellulosic; Biomass; Biofuels

Recommended Citations

Citations

  • Narayana Swamy, N. (2010). Supercritical Carbon Dioxide Pretreatment of Various Lignocellulosic Biomasses [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1269524607

    APA Style (7th edition)

  • Narayana Swamy, Naveen. Supercritical Carbon Dioxide Pretreatment of Various Lignocellulosic Biomasses. 2010. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1269524607.

    MLA Style (8th edition)

  • Narayana Swamy, Naveen. "Supercritical Carbon Dioxide Pretreatment of Various Lignocellulosic Biomasses." Master's thesis, Ohio University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1269524607

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Ohio University and OhioLINK.