The production of bio-based fuels and carbon catalysts from chicken waste

Abstract

From an environmental and economic perspective, converting harmful waste materials into value-added products is very important. This work explores using an equal mixture of chicken waste (CW) and chicken bones (CBs) as a raw material for creating more valuable products. The CW (chicken skin and fat) were de-fatted, and their solid residue leftover was blended with CBs and utilized as a pyrolysis feedstock to create bio-oil (BO) and bio-char (BC). The waste blend was thermally pyrolyzed over a range of temperatures (400–600 °C) and periods (30–150 min) numerous range of heating rates (5–20 °C/min). The highest yield of liquid fractions (61.60%) was achieved at 500 °C for 120 min at a 10 °C/min rate of heating. The BO content of the liquid fraction amounted to 25.225%. According to the FTIR outcomes, the produced BO is a complex mixture of many organic compounds, including carboxylic acids, aldehydes, ketones, esters, and hydrocarbons (alkanes, alkenes, cyclic compounds, etc.). The fuel characteristics of the synthetic BO were similar to those reported for numerous samples of BO in the literature. It also offered its suitability as a synthetic fuel for engines and a probable source of chemical feedstock. The BC leftover after the pyrolysis of the waste mixture was exploited as catalyst support. It was impregnated with different ratios (10–50%) of KOH. The typical sample (40K/BC) was identified by SABET, FE-SEM, EDX, XRD, and FTIR spectroscopy. The efficiency and performance of the 40K/BC catalyst for transesterification of a blend of chicken fat and waste cooking oil to biodiesel (BD) were explored under diverse operating conditions. The highest BD yield (94.88%) was obtained in 90 min at 60 °C reaction temperature using a 4.0 wt% 40K/BC catalyst and 9:1methanol: lipid blend molar ratio. Additionally, the developed catalyst (40K/BC) demonstrated sustained activity after five cycles of recycling and reusing with a BD yield of >84.0%. The BD characteristics met the requirements of ASTM D6751 and EN 14,214. The ester content in the BD amounted to 96.36% based on 1HNMR analysis.