Sorption enhanced reforming of ethanol over novel catalysts and microwave reactor application


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Kimya Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Tezin Dili: İngilizce

Öğrenci: MERVE SARIYER

Asıl Danışman (Eş Danışmanlı Tezler İçin): Naime Aslı Sezgi

Eş Danışman: Timur Doğu

Özet:

Environmental concerns and fast depletion of fossil fuel resources increased the research activities for the production of hydrogen from renewable sources. Hydrogen production through ethanol steam reforming reaction (SRE) has the potential to be used for its on board production on vehicles and with the sorption enhanced process (SESRE), use of CaO for in-situ removal of produced CO2 increases hydrogen production, decreasing the carbon dioxide and carbon monoxide amount. In this study nickel impregnated SBA-15, silica aerogel, commercial mesoporous carbon, the mesoporous carbon by METU were synthesized, characterized and tested in both the SRE and SESRE reactions. In addition to this, for the SESRE reaction, the effect of the divided section packing concept on the hydrogen purity was also investigated. All catalysts gave good catalytic activity in the SRE reaction. The best one was the 10Ni-SA catalyst with the high yield, stable product distribution and low coke formation compared to other catalysts at 600°C. In all the packing concepts, in the pre-breakthrough period, the mole percentage of the hydrogen was nearly 90 % for all catalysts. In the breakthrough period, decrease of hydrogen and increase of CO and CO2 mole fractions were observed, due to saturation of CaO with CO2. Moreover, in the SESRE-M experiments in post-breakthrough period, the mole percentage of the vi products reached the same values with the SRE results for the only 10Ni-SA and 10Ni-P123-SBA-15 catalysts. For the other catalysts, the physical interaction between catalyst and sorbent affects the catalytic activity of the catalyst. The best packing configuration of catalyst and sorbent in the SESRE reaction is three ordered packing concept. Activity test results showed that in-situ removal of CO2 with CaO significantly enhanced hydrogen production by minimizing equilibrium limitations. Results proved the advantages of sorption enhanced process for the production of high purity hydrogen from ethanol. With use of microwave heating system for the 10Ni-SBA-15 catalyst, the coke formation in the spent catalysts for the SRE was decreased from 56% to 3% compared to conventionally heated system.