This work aimed to conduct a kinetic study of cotton stalks (CSs) through TGA to examine the impact of reaction conditions on bio-oil yield derived from CS slow pyrolysis using a tube furnace lab-scale reactor, as well as a characterization of bio-oil and biochar products. The iso-conversional approaches of Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) were applied to estimate kinetic parameter activation energy (E_a) for the range of conversion degrees (α = 0.1–0.9). The kinetic results demonstrated that the average values of E_a for secondary pyrolysis were lower compared to those of primary pyrolysis; this could be explained by the fact that mainly cellulose degrades during primary pyrolysis, which requires more energy to be degraded. The pyrolysis findings indicated that the highest yield of bio-oil was 38.5%, which occurred at conditions of 500 °C and 0.5–1 mm size, while retention time showed an insignificant effect on pyrolysis oil. GC–MS analysis demonstrated that bio-oil is dominated by phenol compounds, which account for more than 40% of its components. SEM and XRD analyses emphasized that biochar is porous and has an amorphous shape, respectively. It can be concluded that these outcomes confirm that CSs have the potential to be a good candidate for a feedstock material for bioenergy production via the pyrolysis process.

Biomass pellets are increasingly recognized as a cost-effective and sustainable renewable energy source worldwide. However, comprehensive sustainability assessments of their production processes are scarce. To address this gap, three distinct scenarios in Northeast China were evaluated using emergy, economic, and environmental analysis methods: corn single production, corn–pellet co-production, and pellet production. A modified method for calculating the environmental loading rate (ELR) was proposed, which accounts for the environmental benefits associated with replacing coal with biomass pellets for heating. The results showed that corn–pellet co-production demonstrates superior energy efficiency compared to corn-only production, but presents a contrasting economic profile. The ELR for corn single production and corn–pellet co-production are 1.57 and 1.63, respectively, with corresponding emergy sustainability indices (ESI) of 0.89 and 0.84. After applying the modified method, the ELR and ESI for corn–pellet co-production were adjusted to 0.84 and 1.63, respectively, and the ESI of pellet production increased from 8.24 to 21.15. Furthermore, processing corn straw into biomass pellets for heating can reduce heating costs by approximately USD 254.26/hm² and reduce emissions of SO₂, NO_x, CO, PM_2.5, and CO₂ by 9.12, 19.82, 580.31, 65.86, and 13,060.66 kg/hm², respectively. Sensitivity analysis revealed that transportation distance and renewable electricity have a greater impact on pellet production than corn–pellet co-production. The ESI for pellet production decreases from 21.15 to 14.02 as transport distance increases from 20 km to 100 km, while it rises to 57.81 as the proportion of renewable energy in the power supply increases from 0% to 100%.