Effect of unsaturation degree on microwave-assisted pyrolysis of fatty acid salts

• Microwave-assisted pyrolysis (MAP) of fatty acid salts was carried out.
• Effect of unsaturation degree on product distribution and composition was investigated.
• Properties of liquid product obtained from MAP of fatty acid salts were measured and analyzed.

This work is aimed to study the effect of unsaturation degree on microwave-assisted pyrolysis (MAP) of fatty acid salts. Sodium stearate, sodium oleate, and sodium linoleate were selected as model compounds. MAP of sodium oleate obtained the highest yield of liquid product. GC–MS analysis of liquid product revealed that MAP of unsaturated fatty acid salt could produce alkadienes, cycloalkanes, cycloalkenes, alkynes and aromatics, which could not appear in liquid product obtained from MAP of saturated fatty acid salt, and unsaturation degree had a great influence on liquid product composition. Analysis of the gas product indicated that MAP of sodium oleate produced more CO2 and CO, while the MAP of sodium linoleate produced more gaseous hydrocarbons and H2. Analysis of the solid char showed that MAP of unsaturated fatty acid salts favors the cyclization and aromatization of pyrolysis vapours. The properties of liquid product were measured and analyzed, which confirmed that MAP of fatty acid salts is a feasible technology to produce high-quality renewable hydrocarbon fuels.