Title: Production of Fuels and Chemicals Through Catalytic Co-pyrolysis of Waste Biomass & Waste Plastics”
Time : 15th December-2023 at 10:00
Venue: Chemical Engineering Department seminar room.
Online Link : https://teams.microsoft.com/l/meetup-join/19%3ameeting_MjJjMGU3ZWQtZmQ1MC00MGExLWI4OTYtYjIyYmNmMjI4YjBh%40thread.v2/0?context=%7b%22Tid%22%3a%22624d5c4b-45c5-4122-8cd0-44f0f84e945d%22%2c%22Oid%22%3a%22b94ff52d-69c6-485c-9770-fd262044df50%22%7d
Abstract:
Valorization of waste biomass to high-quality biofuels and chemicals is an essential process toward sustainable resource utilization and fulfilment of a circular economy. Nevertheless, post-harvest waste biomass such as rice straw, wheat straw, etc, and forestry residues namely wood chips, timber slash, etc. are generally underutilized and add to solid waste disposable problems. Among the agricultural residues, wheat straw contributes a significant quantity as wheat is the main cereal crop in major part of India. Among the various thermochemical conversion processes of biomass , pyrolysis is an effective method for the production of bio-oil. However, the resultant bio-oil is exceedingly acidic and viscous, contains a high amount of oxygenates, and has a low heating value, therefore, finding limited utilization. The main contributing factor for this low-quality is the inherent chemical compositions of lignocellulosic biomass which has a low H/Ceff ratio. Therefore compensating the same by co-reaction of waste biomass with high H/Ceff materials is expected to alleviate the above issues to some extent. In this aspect, waste poly olefinic plastics such as HDPE, LLDPE, and LDPE with a high H/Ceff can form potential co-reactants for biomass co-pyrolysis.
In this research study, wheat straw (WS) biomass co-reacted with recycled waste plastic HDPE in presence of catalysts to produce valuable chemicals and fuels. In the first work, effect of various concentrations of metal (1,5, and 10 wt.% Mn, Ni, and Zn) modified HZSM-5 extrudates on the co-pyrolysis of WS and waste HDPE at a feed mix ratio of 3:1 is investigated. The study revealed that metal-impregnated HZSM-5 especially Ni-modified catalysts produced higher organic-rich phase fractions of bio-oil in comparison to parent HZSM-5. The metal modifiers also yielded less coke formation as compared to parent zeolite. Further, 5%Ni followed by 5%Mn incorporated HZSM-5 generated more aliphatic hydrocarbons, whereas, 1%-Zn modified HZSM-5 produced a more relative proportion of valuable aromatics. In addition, more valuable lighter olefins (C2-C4) obtained in the gaseous product with 5% Mn generated more volume of lighter olefins.
The second study probed thermal behavior, kinetics, and thermodynamic parameters analysis of catalytic co-pyrolysis of wheat straw (WS) and post-consumer (HDPE) waste plastic and their blend in the ratio of 3:1 (w/w) over unmodified and 5%Mn, Ni, and Zn modified HZSM- 5 through thermogravimetric analysis (TGA) at differing heating rates of 5, 10, 20 °C/min. The study evealed that the use of catalysts considerably moderated the average activation energy required for the co-pyrolysis process.
In the third study, a novel metal impregnated (5% Mn, Ni and Zn) -N-doped reduced graphene oxide (RGrO) catalysts synthesized and its effect on co-pyrolysis of various feed mix of WS:HDPE was explored through analytical Py-GC/MS experiments. The study provided the insight into the co-pyrolysis synergy and the impact of the catalysts on the product profile distribution.
The outcome of these studies provide some directions for improving lignocellulosic biomass and waste plastic recycling and converting these wastes into valuable biofuels or chemicals.
Keywords : Co-pyrolysis , HZSM-5 Extrudates, N-doped Reduced Graphene oxide, TGA