To explore the patterns of essential oil synthesis and the optimal harvesting period of citral-type Camphora officinarum Nees ex Wall (C. officinarum) at different growth stages, three varieties (C1, C2, C3) from the citral-type C. officinarum coppice were taken as research objects. During the leaf growth cycle from February 2022 to January 2023 (12 periods in total), their morphological indicators, biomass, essential oil yield, chemical components, and output were determined. As a natural monoterpenoid widely used in the food additive, pharmaceutical intermediate, and flavor/fragrance industries, citral-related research is of great significance for improving the breeding value of citral-type C. officinarum germplasm resources. The results showed that: (1) The leaf area, total biomass, and leaf-branch ratio of the three varieties all reached the maximum in Period I (late August, full fruit stage), among which the leaf biomass and total biomass of C1 were significantly higher than those of C2 and C3. (2) The essential oil yield based on dry weight of leaves (0.53–2.79%) was significantly higher than that of branches (0.48–0.7%). Citral (geranial and neral) was the main component of the essential oil; the citral contents in C1 and C2 were the highest in Period G (late June, early fruit stage) (78.38% and 71.78%, respectively), while that in C3 peaked in Period F (late May, late flowering stage) (70.46%). (3) The total essential oil yield reached the peak in Period I, with C1 being significantly higher at 20.19 ± 1.88 g/plant than C2 (13.8 ± 0.61 g/plant) and C3 (16.47 ± 0.87 g/plant). Comprehensive analysis indicated that C1 was identified as the top-performing cultivar among citral-type C. officinarum, and July–August was the optimal harvest period. During this period, both essential oil yield and citral content could be balanced to maximize economic benefits.

The oxidation of filter cake particles (FCPs) is beneficial for preventing filter media blockage during the hot filtration of raw biomass gasification gas. The influence of particle characteristics on hot oxidative filtration was investigated through characterization, kinetic study, and lab-scale experiments. The characterization results indicated that FCPs are particles with C content of more than 60%, containing –CH_n and C=O functional groups. After pyrolysis treatment, these functional groups gradually diminished, while the degree of atomic nucleus condensation increased. The oxidation kinetic calculation indicated that the oxidation activation energy of particles ranged from 55.24 to 117.84 kJ/mol, and higher treatment temperatures could reduce the particle reactivity. The hot oxidative filtration at 400 °C revealed that the primary reaction was C + O₂ = CO₂ rather than combustion or oxidation of combustive gas components. Furthermore, it was observed that the active minerals on the surface of carbon particles would promote the catalytic oxidation of CO. Experimental findings confirmed that the untreated FCPs containing abundant –CH_n functional groups could effectively react with low-concentration O₂. However, the presence of active minerals on the particle surface likely promoted CO oxidation within the FCP layer, thereby reducing the calorific value of the product gas.