Transportation fuel production by combination of LDPE thermal cracking and catalytic hydroreforming

Abstract

Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effect of the Ni loading on Ni/h-Beta is investigated in the hydroreforming of the oils form LDPE thermal cracking. h-Beta samples were impregnated with Ni nitrate, calcined and reduced in H2 up to 550°C to achieve different Ni contents: 1.5%, 4%, 7% and 10%. Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. Hydroreforming tests were carried out in autoclave reactor at 310°C, under 20 bar H2, for 45 min. Ni content progressively increased the amount of gases at the expenses of diesel fractions, while gasoline remained approximately constant about 52-54%. Maximum selectivity to automotive fuels (∼81%) was obtained with Ni 7%/h-Beta. Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. High cetane indices (71-86) and octane numbers (89-91) were obtained over all the catalysts. Regarding the different studied Ni contents, Ni 7%/h-Beta constitutes a rather promising catalyst for obtaining high quality fuels from LDPE thermal cracking oils.

Keywords: Hierarchical zeolites; Hydroreforming; Low density polyethylene; Nickel; h-Beta.