Key words: poultry manure, brawn coal, supercritical water oxidation, heat evolution, contaminants
The results of joint supercritical water oxidation (SCWO) on the poultry manure (PM and brown coal (BC) mixtures continuously fed as a NaOH stabilized (0.8 wt. %) slurry into a tubular reactor at 25 MPa, temperature gradient along its vertical axis of 390— 600 °C, varied reactant flow rate and concentrations of PM and BC in the slurry are presented. The addition of BC leads to the 1.5—1.8-fold reduction of the total energy consumption by ohmic heaters depending on the content of combustible matter in the slurry. The forming gas mixture contains CO2, N2, and trace amount of N2O. Calcium and sodium carbonates, phosphates, and aluminosilicates are dominated in the composition of ash residues. The total content of phenols (17—32 μg/dm3) and polycyclic aromatic hydrocarbons (2—4 μg/dm3) in the effluent depends on the PM concentration in the slurry and does not exceed the level of their maximum permissible concentration in wastewater. The formation of HNO3 and H2SO4 during the SCWO process results in corrosion of construction materials and increases the content of chromium, copper and nickel in the aqueous effluent. The mechanisms of transformation of organic and mineral components of PM and BC are discussed.
doi:10.34984/SCFTP.2024.19.4.005