Study on pyrolysis characteristics of lignocellulosic biomass impregnated with ammonia source

•Carbonyl compounds were converted into nitrogenous heterocyclic compounds (NHCs).•The contents of NHCs and phenols in URL are very high.•The quantity of compounds in SRL and PRL reduces remarkably.•The reaction mechanism for the formation of NCHs was proposed.

The current study presents the pyrolysis characteristics of rice husk impregnated with different kinds of ammonia source (ammonium acetate, urea, ammonium sulfate and ammonium dihydrogen phosphate) in a fixed bed reactor. The introduction of ammonia source in pyrolysis process achieved the conversation from carbonyl compounds to nitrogenous heterocyclic compounds. The liquid product of urea-impregnated biomass has higher content of nitrogenous heterocyclic compounds (8.35%) and phenols (30.4%). For ammonium sulfate and ammonium dihydrogen phosphate-impregnated biomass, the quantity of compounds in liquid products reduces remarkably, and the gas products are rich in CO and H2. All the solid products of pyrolysis have great potential application in biochar-based fertilizer and activated carbon for their high N content.