Renewable Energy from Waste: Investigation of Co-pyrolysis between Sargassum Macroalgae and Polystyrene

Abstract

Co-pyrolysis of the seaweed Sargassum and polystyrene was investigated as a potential source of renewable energy. Sargassum is a brown macroalgae, posing a large disposal problem for beaches worldwide, and polystyrene is the plastic least recycled in the U.S. Although macroalgae bio-oil cannot be directly used as a result of a high oxygen content and low heating value, co-pyrolysis of macroalgae with low-oxygen-content waste polystyrene can enhance oil quality. Pyrolysis of pure Sargassum was conducted to determine the temperature producing the highest percent oil (600 °C). Co-pyrolysis of four different mixture ratios of Sargassum and polystyrene (5, 15, 25, and 33% by weight) was then conducted at 600 °C. Feedstocks and pyrolysis products (liquid oil and water, gas phase, and solid phase) were characterized using elemental analysis, thermogravimetric analysis, gas chromatography, surface area and adsorption isotherm analysis, and nuclear magnetic resonance. Co-pyrolysis with polystyrene improved the quality and quantity of the oil compared to pyrolysis of Sargassum alone. The oil quantity increased, from 3% for Sargassum alone to 29% for a mixture of 67% Sargassum and 33% polystyrene. Co-pyrolysis improved the oil potential heating value and decreased its potential for producing air pollution when combusted, by lowering its nitrogen content. Co-pyrolysis produced a gas with up to 7% hydrogen and 30% methane, which can be burned as a fuel. Co-pyrolysis of Sargassum and polystyrene, therefore, shows promise as a method for generating fuel and reducing disposal problems.

Golden seaweed tides from beach inundations as a valuable sustainable fuel resource: Fast pyrolysis characteristics, product distribution and pathway study on Sargassum horneri based on model compounds

“…The T m values were 268.1 °C, 333.9 °C, 374.4 °C and 280.8 °C for S. horneri, AGA, MCC and SBP, respectively, from which we can see that the T m of S. horneri was similar to that of its protein and polysaccharide fractions. This finding has also been confirmed in the aforementioned literature on the pyrolysis mechanism of seaweed polysaccharides [32]. Moreover, the devolatilization index D i characterizes the performance of volatile matter release.…”

Thermal behavior and kinetics of co-pyrolysis of cellulose and polyethylene with the addition of transition metals

“…It is reported by Dorado et al that the yield of alkyl benzenes from the catalytic fast pyrolysis of CL along with polyethylene terephthalate was greatly enhanced compared with CL alone [12]. Kositkanawuth et al found that co-pyrolysis of biomass with polystyrene led to the improvement of the quality and quantity of the oil compared to pyrolysis of Sargassum alone [13]. Particularly, the oil quantity increased from 3% for Sargassum alone to 29% for the mixture of 67% Sargassum and 33% polystyrene.…”

Study on kinetics, thermodynamics and co-pyrolysis studies of sugarcane bagasse and expanded polystyrene

“…However, most of the generated thermocol wastes are subjected to land lling, and energy recovery respectively by use of thermochemical conversion methods like combustion, pyrolysis, etc (Lopez et al, 2017) (Uttaravalli et al, 2020). Many researchers have explored the co-pyrolysis kinetics of biomass and polystyrene, including (epelioullar & Pütün, 2013), (zsin & Pütün, 2017, (Alam et al, 2020), (Ng et al, 2018), (Kositkanawuth et al, 2017), (zsin & Pütün, 2018, (H (Pradhan et al, 2020). However, kinetic, thermodynamic, and co-pyrolysis experiments combining sugarcane bagasse (SB) and thermocol waste (TW) have not been documented in the literature.…”