CO2 Removal from Natural Gas Using N-Modified Silicate Fiberglass Materials
Тезисы доклада (Meeting Abstracts),
251st ACS National Meeting & Exposition
13-17 мар. 2016
ACS National Meeting Book of Abstracts
Институт катализа им. Г.К. Борескова СО РАН
A series of fiberglass materials of silicate origin was modified with organic N-bases (TMAH, in particularly) in order to adsorb selectively CO2 from different gaseous feedstock including natural gas. These fiberglasses were characterized by means of SEM in combination with EDX, FTIR, NMR etc. During this treatment the continuous cleavage and formation of new silicate network takes place. The insertion of N+ cations into the Si-O-Si bonds terminates the oligomerization process, so that thin 100-200 nm gel-like film formed on fiberglass surface. The density and viscosity of this phase is noticeably lower compared with pristine fiberglass due to shorter silicate chains. The formed Si-O-N+(CH3)4 species are responsible for CO2 adsorption, since the number of adsorbed molecules of carbon dioxide as monodentate carbonate species coincides well with concentration these sites estimated by NMR and IRS. The samples treated with TMAH demonstrated good CO2 adsorption capacity exceeding 5% wt. The broadening of NMR lines caused by limitation of the methyl groups rotation in TMAH molecule allowed to estimate quantitatively the viscosity (7000 cP) of low dense phase and diffusion coefficient (1.6×10-9 cm2/s). The H2O-stimulated carbon dioxide desorption occurs via formation of intermediate less stable hydrocarbonates, which decompose at low enough temperatures. It allows to state that N-modified fiberglass adsorbent is regenerable at rather mild conditions. The stability of this new adsorbent was confirmed by number of adsorption – desorption cycle.