Production of diesel-range oil through pyrolysis of polyolefins recovered from municipal solid waste.

Pyrolysis is an effective method to valorize plastic waste and obtain value-added fuels. This study adopted the ANN-GA (artificial neural network-genetic algorithm) coupled with a central composition factorial design to optimize the oil production from the pyrolysis of waste polyolefins (WP). The interactive effects of PE mass fraction (20-80 wt%), residence time (20-60 min), and carrier gas flow rate (0-100 mL/min) on the yields of WP pyrolysis products were investigated extensively by ANN. Moreover, the highest WP pyrolysis oil production of 78.87 wt%, optimized by GA, was obtained under 80 wt% PE, 60 min, and 0 mL/min. It was found that the different conditions of PE mass fraction, residence time, and carrier gas flow rate did not change the types of oil's main functional groups (-CH2-, -C=C-, -C=CH2, -CH3, and =C-H). The conditions affected the WP pyrolysis oil fractions significantly. The highest diesel selectivity of 91.42% was obtained under 20 wt% PE, 20 min, and 0 mL/min. Additionally, according to the interactive effects of different conditions on the productions of WP pyrolysis products, the pyrolysis pathways were proposed to understand the pyrolysis mechanism of WP better.

Integrating in-bed gas looping and CO2 capture in the FeD-Latrine.

Sanitation equity and climate actions are world concerns stated by the United Nations in the Sustainable Development Goals. A significant source of greenhouse gas emissions is inputted by human wastes, either in developing countries through wastewater treatment plants, or in the underdeveloped world, through anaerobic digestion of fecal sludge in pit latrines. For the first time, an integrated process for CO2 reduction and capture is implemented in a thermally sustainable, latrine-like device that destroys fresh human feces using smoldering combustion, the FeD-Latrine. A gas looping oxidizes combustible gases and creates favorable conditions to capture CO2 in bed. CH4 and H2 molar fractions are decreased around 90 % and 30 %, respectively. CaO used as a sorbent captures up to 8 mmol of CO2 per gram, forming a stable CaCO3. Compared to kinetic-dominant processes for CO2 capture, we obtain an efficiency of around 52 %. Our findings show that using the FeD-Latrine to replace typical pit latrines reduces 60 % of the CO2-eq emissions.