NiO/Dolomite Catalyzed Steam/O₂ Gasification of Different Plastics and Their Mixtures

Abstract

The catalytic gasification of different individual plastics and their mixtures with a dolomite supported Ni catalyst was evaluated in a drop-tube fixed-bed reactor. The influence of the Ni loading level and the interactions of mixed plastics during steam gasification were both examined. A 5 wt % NiO/dolomite catalyst gave the highest degree of carbon conversion for all evaluated plastics and mixtures. A mixture of the four types of plastic that matched the estimated weight ratio of real plastic waste revealed a lower gas yield than predicted, suggesting their interaction during gasification. The mixtures which contain high-density polyethylene or low-density polyethylene at 0.75 wt/wt led to a reduced gas production, while polystyrene increased it, especially in the polystyrene–polypropylene binary mixture with a markedly higher H2, CO, and CO2 production level than that expected. Thus, it would be beneficial to screen plastic types prior to the generation of suitable gas products.

Syngas production from polyolefins in a semi‐batch reactor system

“…The increased reforming activity, also observed in the literature, 19 can further be explained by the aromaticity of PS. Due to the π* electron system, the aromatic pyrolysate from the PS will bind more strongly to the Ni catalyst under high‐temperature reforming conditions, increasing reforming activity over the Ni catalyst 29,30 …”

Co-pyrogasification of Plastics and Biomass, a Review

“…Pyro-gasification (with air, pure oxygen, steam and carbon dioxide or their mixtures as gasifying agent) of pure plastics is treated in many publications: Xiao et al, 2007 [13], Ongen, 2016 [14], Toledo et al, 2011 [15], Erkiaga et al 2013 [16], Wu and Williams, 2010 [17], Acomb et al, 2014 [18], Wilk and Hofbauer, 2013 [19], Kannan et al, 2013 [20], Cho et al, 2013 [21], [22], Cho et al, 2014 [23], Lopez et al, 2015 [24], Arena et al, 2011 [25], Arena and Gregorio, 2014 [26], Kim et al, 2011 [27], Lee et al, 2013 [28], Salbidegoitia et al 2015 [29]. Pyrogasification of mixed plastics is treated by Friengfung et al, 2014 [30], Martinez-Lera et al, 2013 [31], Saad and Williams, 2016 [32]. It is clear that pyro-gasification as waste treatment method does not so much target pure plastics, or plastics that can easily be purified, as these are preferably treated by mechanical recycling, but rather mixed plastics and plastics mixed with or contaminated by other waste.…”

A sequential process for hydrogen production based on continuous HDPE fast pyrolysis and in-line steam reforming

“…The studies dealing with the direct production of H 2 from waste plastics by reforming have been carried out following two main strategies: i) gasification with a reforming catalyst arranged in situ [17,18] and ii) pyrolysis and in line reforming [19][20][21][22][23][24]. The latter strategy provides clear advantages compared to the direct gasification strategy due the lower operating temperature.…”