Purification of Biogases from Siloxanes by Adsorption: On the Regenerability of Activated Carbon Sorbents

Abstract

The effective adsorption capacity of hexamethycyclotrisiloxane (HMCTS), a common siloxane impurity in biogases, by solids, such as activated carbons (ACs), silica, and zeolite, has been evaluated in laboratory experiments using synthetic biogas. The adsorption mode of this molecule has been investigated by infrared (IR) spectroscopy. Similar experiments have been performed with exhausted ACs taken from a commercial adsorption column treating real landfill biogas. It has been found that pure ACs are efficient sorbents for HMCTS, better than alkali-impregnated ACs and inorganic solids. It was found that HMCTS converts in part upon adsorption into silicone and silica. This is likely a reason of the only partial regenerability of ACs after use in purification of real biogases.

Purification of landfill biogases from siloxanes by adsorption: A study of silica and 13X zeolite adsorbents on hexamethylcyclotrisiloxane separation

“…The most efficient solids to remove siloxanes are activated carbons (ACs) [12][13][14]. However, according to both landfill gas treatment practice and laboratory experiments [12,15], ACs can only be partially regenerated from siloxanes after use. This makes the cost of the adsorbent quite significant.…”

Effect of the synthesis conditions of Ni/Al2O3 catalysts on the biogas decomposition to produce H2-rich gas and carbon nanofibers

“…Besides this, DRM using biogas can be classified as environmentally friendly due to the renewable character of the feedstock. However, the utilization of biogas in the DRM faces many challenges, being the energy required to carry out the process (CH 4 + CO 2 → 2H 2 + 2CO, ∆Hº= 247 kJ·mol -1 ), catalyst poisoning caused by biogas minor compounds [11][12][13] and catalyst deactivation by carbon deposition [14] among the most important.…”

Avaliação Preliminar Do Biogás De Um Aterro Sanitário Para Geração De Energia Elétrica

“…Embora materiais como o óxido de ferro e o carvão ativado impregnado com químicos sejam considerados mais eficientes para remoção de H 2 S, o carvão ativado convencional geralmente apresenta maior potencial de adsorção de siloxanos, ao mesmo tempo em que pode ser regenerado com maior facilidade, ao passo que os óxidos de ferro perdem a maior parte de sua capacidade de adsorção e os carvões ativados impregnados não podem ser regenerados e geram resíduos perigosos (ZICARI, 2003;TURCO et al, 2016;FINOCCHIO et al, 2009 (NEVES, 2015;SILVESTRE, 2015). Porém, a comparação com esses trabalhos não é totalmente satisfatória, uma vez que foram analisados outros drenos em condições operacionais e metodológicas diferenciadas.…”