Analyzing the influence of feedstock selection in pyrolysis on aviation gas turbine engines: A study on performance, combustion efficiency, and emission profiles

Abstract

Commercial aviation is primarily reliant on fossil fuels, yet the depletion of these sources and the consequences of climate change necessitates the exploration of sustainable alternatives. The pyrolysis process offers a viable method for producing biofuels from various feedstocks. This research examines the combustion, emission, and performance characteristics of biofuels derived from agricultural residues, waste tyres, and plastics using pyrolysis. Pyrolysis oils derived from forestry or agricultural products exhibit high viscosity and moisture content, which impairs combustion efficiency and increases carbon monoxide (CO) from 70 % to 187 % and unburned hydrocarbon (UHC) emissions. Conversely, pyrolysis oils from plastics and waste tyres provide stable combustion with carbon monoxide and total hydrocarbon emissions (THC) comparable to those of commercial jet fuel. However, nitrogen oxide (NOX) emissions are significantly elevated from 57 % to 157 %. Engine performance tests demonstrated that forestry pyrolysis oils result in thrust loss due to their high viscosity value (14.3–113 mm2/s) and low calorific value (17.3–31.7 MJ/kg). In contrast, plastic and tyre pyrolysis oil perform similarly to commercial jet fuels but may potentially cause performance loss due to their high aromatic content (>47.67 %). Overall, upgrading the viscosity, moisture, and aromatic content of pyrolysis oils can enhance their suitability as alternative aviation fuels. These improvements could assist the aviation sector in achieving its carbon-neutral goals by making pyrolysis oils competitive with conventional jet fuels.