As societies across the globe urbanize, we are producing increasing amounts of solid waste and demanding ever-more energy sources. We must change our thinking from the need to strictly manage municipal solid waste (MSW) to the ability to valorize it into renewable source of carbon. One potential solution is to integrate pyrolysis of MSW to recover liquid and gaseous biofuels and a solid biochar, with CO<sub>2</sub> activation of the biochar to produce activated carbons for water treatment. We demonstrate surface areas of resulting MSW-biochars higher than 300 m<sup>2</sup>/g, with the lower pyrolysis temperature and higher activation temperature yielding the highest areas. However, given MSW’s high water content, we also explore the hydrothermal carbonization (HTC) of MSW. HTC at harsher conditions (higher temperatures, longer residence times) decrease the solid yield while increasing the higher heating value, fixed carbon, and elemental carbon. Energy yields upwards of 80% can be obtained at both intermediate and high temperatures (220 and 260-280 °C), but the thermal stability and reactivity of the intermediate hydrochars suggest the formation of a secondary reactive char that condenses on the surface of the primary hydrochar, putting into question the ability to use the hydrochar as a replacement solid fuel in existing combustors. However, it is further demonstrated that these hydrochars can undergo a secondary thermal conversion whereby pyrolysis liquids are extracted as a biofuel source, and the resulting hydrochar can be upgraded to a highly adsorbent activated carbon used to treat both organic and heavy metal contaminated wastewater.

Multiple thermochemical pathways for municipal solid waste valorization to biofuels and bioproducts

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.