TY JOUR TI PROCESSING SUNFLOWER HUSK INTO HIGH STRENGTH COAL BRIQUETTES KW conductive pyrolysis KW sunflower husk KW high-strength coal briquettes KW plant waste KW alternative energy sources JO Vestnik of Kazan State Agrarian University AU Tuncev, D.V. AU Har'kov, V.V. AU Kuznecov, M.G. PY 2020 IS 14 PB Kazan state agrarian University