Recent Progress in Low-Cost Catalysts for Pyrolysis of Plastic Waste to Fuels

Abstract

The catalytic and thermal decomposition of plastic waste to fuels over low-cost catalysts like zeolite, clay, and bimetallic material is highlighted. In this paper, several relevant studies are examined, specifically the effects of each type of catalyst used on the characteristics and product distribution of the produced products. The type of catalyst plays an important role in the decomposition of plastic waste and the characteristics of the oil yields and quality. In addition, the quality and yield of the oil products depend on several factors such as (i) the operating temperature, (ii) the ratio of plastic waste and catalyst, and (iii) the type of reactor. The development of low-cost catalysts is revisited for designing better and effective materials for plastic solid waste (PSW) conversion to oil/bio-oil products.

Advances in the Pyrolysis Process and the Generation of Bioenergy

“…Several authors have already published works testing different catalysts, in different process configurations, attesting to diverse improvements in obtaining bio-oil. Among these improvements in the use of catalysts in the fast pyrolysis process, it is worth mentioning: [60].…”

“…• Depending on the catalyst(s) selected, there may be a significant increase in aromatic compounds (up to 50%), giving greater stability to the bio-oil and providing a potential use as a fuel [60,65].…”

“…Despite promising experimental results, the fast pyrolysis process using catalysts still needs to overcome some obstacles to reach the industrial level. The basis for these challenges is the development of catalytic reactors capable of supporting the pyrolysis atmosphere without expressive rates of catalyst deactivation, expanding the selection of desired products in bio-oil, in addition to efficient developments in the recovery and regeneration of catalysts [41,60]. works on catalytic pyrolysis of biomass at different scales, the characteristics of the catalysts used as well as the yield in bio-oil.…”

Recent Trends in the Pyrolysis of Non‐Degradable Waste Plastics

“…Zeolite catalysts were selected since their surface feature Lewis‐ and Brønsted‐acidic sites: the abstraction of a hydrogen ion from the waste polymer is initiated by the Lewis acid site, while the addition of a proton to the C−C bond is carried out by the Brønsted acid sites. Therefore, if the catalytic surface contains more Brønsted acid sites, more hydrogen is provided for the double bond [95,96] …”

“…Therefore, if the catalytic surface contains more Brønsted acid sites, more hydrogen is provided for the double bond. [95,96] The catalysts employed for the pyrolysis of waste plastics can be applied either directly in the reaction system (in situ) or through a second reactor for the actual catalytic process (ex situ). [97] A recent study by Fan et al used continuous-stirred microwave pyrolysis (CSMP) and a batch microwave system for the pyrolysis of linear LDPE (LLDPE) in the presence and absence of HZSM-5.…”