Utilization of solid residue from hydrothermal liquefaction of breadfruit pulp for the production of bio-briquette using cassava starch as binder

Abstract

The generation of agro-waste as a result of increase in agro and food processing activities is on the increase due to rapid increase in human population. Hence the need to eliminate these waste by converting them into a useful product or energy source. This work presents the use of bio-char from hydrothermal liquefaction of breadfruit pulp to produce bio-briquettes with cassava starch as a binder. The response surface method using design expert was used to design the experiment with particle size, press pressure and binder dosage as factors, to determine the parameter combination that will produce briquettes of high energy density. The briquette with the highest calorific value 26.75 MJ/kg was produced at the parameter combination of 450 mm ⁻⁶ particle size, 5 MPa press pressure, and 20 % binder dosage. The ultimate analysis carried on the produced briquette gave carbon, hydrogen, nitrogen and sulphur content of 47.22 %, 3.88 %, 0.69 %, and 0.42 % respectively, with oxygen content of 4.79 % by percentage mass difference. While the proximate analysis gave moisture, ash, volatile matter, and fixed carbon content of 7.8 %, 3.9 %, 43.7 %, and 44.6 % respectively. Other characterization test carried out gave combustion rate of 4.5 g/min, ignition time of 3.5 min, density of 0.86 g/cm ³, compressive strength of 8.31 N/mm ², shatter index of 0.89, and hydrophobicity of 61.3 %. These findings shows that briquettes produced with bio-char from HTL of breadfruit pulp can be used as solid fuel for domestic and mini-industrial heating purposes, as well as eliminate waste from processing of breadfruit.