DESIGN FEATURES OF THE EXPERIMENTAL UNIT AND NUMERICAL STUDIES OF BIOMASS THER-MOCHEMICAL PROCESSING. PART 3 THE INFLUENCE OF HEAT CAPACITY AND THERMAL DECAY EFFECT ON THE HEATING RATE OF WOOD BIRCH PARTICLE BED

• Дата: 2024
• Автори: Rokhman , B. B., Kobzar , S. G.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: Institute of Renewable Energy National Academy of Sciences of Ukraine 2024
• Теми: fixed bed; biomass; Wood Birch; thermal conductivity; pyrolysis; gas; temperature; thermal energy; recycling; electric heater.
• Онлайн доступ: https://ve.org.ua/index.php/journal/article/view/495
• Назва журналу: Vidnovluvana energetika

The third part of this work is devoted to the theoretical study of the influence of biomass heat capacity, boundary condi­tions, recirculation of pyrolysis gases, external and internal heat flows on the heating time of a fixed pyrolysis bed consisting of Wood Birch particles of 10 mm equivalent diameter. Three options for heating the bed were considered: a) electric heating of the outer and inner surfaces of the pyrolyzer; b) electric heating of the outer surface and heating the inner surface of the pyrolyzer by combustion products; c) two electric heaters and recirculating pyrolysis gas with a temperature of 800 °С. It is shown that: 1) taking into account the thermal decomposition thermal effect in the equation of thermal energy of particles leads to a decrease in the biomass bed heating time by 1.33 times and an increase in the bed heating rate to 987 °С/min; 2) recirculation of high-temperature pyrolysis gases entering the pyrolyzer limited by the outer D = 220 mm and inner d = 150 mm diameters, reduces the bed heating time by 1.39 times, resulting in increasing the particle heating rate from 987 to 1373 °С/min; 3) pyrolysis gases recirculation contributes to the rapid pyrolysis organization when the pyrolyzer outer diameter increases from 220 to 240 mm and from 220 to 300 mm, resulting in a decrease in the bed heating rate from 1373 to 1295.3 °С/min and from 1373 to 1223 °С/min, respectively; 4) the calculated composition of the mixed pyrolysis gas at tg = 800 °С: CO2 = 7.14 %, CO = 51.4 %, H2 = 15.56 %, C1.16H4 = 23.72 % (CH4 = 16.6 % and C2H4 = 7.116 %), N2 = 0.296 %), is in good agreement with the results of the Wood Birch pyrolysis experiment at tg = 800 °С: CO2 = 8.3 %, CO = 50.70 %, H2 = 16.8 %, CH4 = 16.2 % and C2H4 = 7.9 %.