Improving of Pyrolysis Oil from Macroalgae Cladophora glomerata with HDPE Pyrolysis Oil

Abstract

The slow pyrolysis of macroalgae at moderate temperatures in the reactor used resulted in an oil with a slightly better calorific value than that of the literature, but the other properties were not convincing. Therefore, co-pyrolysis with HDPE offers a way out in this study. However, this did not improve the property profile as a fuel, as the co-pyrolysate was incombustible due to its high water content. Only a mixture of the pyrolysis oil from algae and of the HDPE wax from the initial pyrolysis of HDPE resulted in a diesel-like product: the density was from 807 kg m−3, the viscosity 3.39 mm2 s−1, the calorific value was 46 MJ kg−1, and the oxidation stability was 68 min. The isoparaffin index indicates only a low branching of the paraffins, and therefore a low research octane number of 80. The blend did not need any further stabilizing additives.

Comparison of Antioxidants to Increase the Oxidation Stability of Pyrolysis Oils of Three Plastics Using Iodine Value

“…The only parameter of distillates that is between 55% and 86% below the requirements for gasoline and diesel fuels is oxidation stability. The low oxidation stability of the oils and distillates is probably due to the high content of unsaturated, double-bonded compounds (alkenes, alkadienes, aromatic compounds), the presence of which was confirmed by NMR spectral analysis of the oils (published in [21,33]) and the iodine values determined. Further experimental studies are required to increase the oxidation stability of the distillates.…”

“…The raw materials used for pyrolysis were high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS), which came from a secondary sorting plant (JSC Waste Management Center of Klaipeda Region, Klaipeda, Lithuania). Algae pyrolysis oil comes from another study, whose results were published in [21]. In this study, macroalgae of the species Cladophora glomerata from the northern beach of Klaipeda (Lithuania) were heated to three different final pyrolysis temperatures.…”

“…Three antioxidants were added to these distillates: pyrocatechol, phenol, and freshly prepared algae pyrolysis oil from another study. The oxidation stability and the change in the iodine number over time according to the method described in the literature [21][22][23][24] were determined and discussed.…”