The large-scale cultivation of salt-tolerant rice supports food security, and its straw offers potential for resource utilization, but studies on energy applications, particularly in microwave-assisted fluidized bed pyrolysis (MFBP), are still limited. This work compared salt-tolerant and conventional rice straw, examined fluidization effects on product distribution, and explored co-pyrolysis with peanut shell and Ascophyllum nodosum, while analyzing nitrogen migration during pyrolysis. Results indicate that salt-tolerant rice contains higher alkali metals and lipids, producing bio-oil dominated by acids and esters. The high thermal stability of solid-phase nitrogen in salt-tolerant rice inhibits the release of nitrogen. Bulk density and fluidization strongly influenced product distribution and secondary tar cracking, while fluidization not only shortened the reaction time but also promoted the release of nitrogen-containing gases. As pyrolysis proceeded, unstable nitrogen species were transformed into stable heterocycles such as pyridine and pyrrole. During co-pyrolysis, the addition of peanut shells inhibited the decomposition reaction of biomass and the generation of bio-gas, but increased the bio-oil yield by up to approximately 10%. In contrast, the introduction of Ascophyllum nodosum promoted the decomposition reaction of biomass and maximally increased the hydrogen yield by about 4.5 mmol/g. Gas-phase secondary combination reactions of free radicals promoted macromolecular formation in bio-oil while suppressing gas release, whereas aldehydes and acids reacted with NH 3 , reducing nitrogen transfer to the gas phase. This study provides a basis for energy utilization of salt-tolerant rice straw. • Valorization of salt-tolerant rice straw via microwave fluidized-bed pyrolysis. • Fluidization and bulk density critically govern product distribution and N fate. • Co-pyrolysis with algae maximizes H 2 yield and suppresses gaseous N. • NH 3 fixation by aldehydes/acids shifts N from gas to liquid products.
Xu et al. (Thu,) studied this question.