Sintayehu, Nibret (PhD)Amanuel, Mengistu2021-08-162023-11-102021-08-162023-11-102021-04http://etd.aau.edu.et/handle/12345678/27680Renewable alternative energy sources have become more popular in recent years and biomass is one of them. Biomass is used as an alternative energy resource and available in huge quantity. Wood is a primary energy source widely used for domestic consumption all over the world. Sawdust of Cupressus Lusitanica is mostly available in various wood workshops throughout Addis Ababa, Ethiopia. The main objective of this study is to enhance the physical and combustion properties of sawdust briquettes through hydrothermal pretreatment (HPT) of the raw biomass and addition of molasses as a binding agent. The effects of HPT temperature (taken at 240°C, 280°C, 320°C) and molasses wt% (0%, 10%, 20%) on the physical and combustion properties of the resulted briquettes prepared from the sawdust of Cupressus Lusitanica with particle size range(1mm-0.5mm) were studied. Dwell time of 45sec and briquetting pressure of 10MPa were kept constant during briquette production. The density, moisture content (MC), volatile matter (VM), ash content (AC), fixed carbon (FC), and high heating value (HHV) of the resulted briquettes were investigated and compared with raw sawdust and briquettes from other studies. This study revealed that the physical and combustion properties of biomass briquettes can be improved by hydrothermal pretreatment of the raw biomass whereas binder addition only improves the mass density of the briquettes at the expense of their combustion properties. Hydrothermal treatment was beneficial to the physical properties of the resulted biomass briquettes; density and durability of the untreated briquettes B00(HPT = none, binder wt% = 0%), B01(HPT = None, binder wt% = 10%), B02(HPT = none, binder wt% = 20%) were lower compared to the HPT briquettes. The optimum operating conditions were determined to be HPT = 320OC and binder wt% = 0%; the response variables at this optimum are as follows: density = 747.47kg/m3, durability = 99.99, MC = 9.61%, VM = 52.2%, AC = 2.87%, FC = 35.4%, HHV = 20.74 MJ/Kg.en-USMolasses BinderSawdust BriquettesHydrothermalCombustionPre-TreatmentThesis