ENHANCING THE PYROLYTIC GAS PRODUCTION GENERATED BY SLOW PYROLYSIS USING A FIXED-BED PROLYZER

Abstract

The biomass slow pyrolysis using the fixed-bed pyrolyzer is a simple and inexpensive technique that can be used in small farms comparing to the complex and expensive technology of the fast pyrolysis. However, slow pyrolysis primary produces bio-char and lower yields of bio-oil and pyrolytic gas. Thus, there is urgent need to enhance pyrolytic gas production under the slow pyrolysis conditions on the account of bio-char due to the advantage of using the gas in wide applications in farm. Hence, this work aims to fabricate and operate a small-scale fixed bed pyrolyzer to enhance the pyrolytic gas productivity from the ground pieces of Mango trees Pruning Logs (MPLs) under slow pyrolysis conditions (heating rate of 0.01-1 oC/s, vapor residence time of 4 min.) and full absence of oxygen. The pyrolytic gas production was investigated under different final pyrolysis temperatures of 300,350 and 400°C, particle length ranges of 1-5, 10-15 and 20-25 mm. The obtained results revealed that, the increase of pyrolysis temperature from 300-400°C and decrease of the ground MPL length from 20-25 to 1-5 mm was accompained with explicit increment in the pyrolytic gas concentration, gas yield, higher heating value of pyrolytic gas (HHVg) and energy conversion efficiency by about 34.28%, 61.15%, 12.68% and 66.10%, respectively along to high concentrations of the combustible gases )e.i. H2, CH4). Additionally, the optimal cost per energy unit of pyrolytic gas (0.085 EGP/MJ or 0.005 $/MJ) is lower than cost per energy unit of the natural gas and LPG by about 11.45% and 75.07%, respectively.