The effects of Clay, Gum Arabic and Hybrid binders on the properties of Briquettes

Abstract

This study set out to determine the effects of clay, gum Arabic and hybrid binders on the physicothermal and mechanical property of briquettes. The hybrid binders, gum Arabic and clay, were used with carbonized rice and coffee husks to developed briquettes under low pressure. Their respective weights were as follows: clay binders (2.4%, 3.6%, 4.7%, 5.8%, 6.9%); gum Arabic binders: (2.4%, 3.6%, 4.7%, 5.8%, 6.9%) and: hybrid binders were (4.7%, 6.9%, 9%, 11.1%, 13%). To these were added 200 g of combined biochars of rice and coffee husks. The physical properties, density and calorific value of the developed bio-composite briquettes were determined using thermogravimetric analysis and bomb calorimeter, respectively. The compressive strength was determined using Universal Test Machine. The thermal properties were determined using water boiling time protocols. The particulate matter of 2.5 was determined using filter based gravimetric while the Carbon Monoxide and Carbon Dioxide levels were determined by electrochemical cell and dispersive infrared sensors, respectively. The results for the developed combined biochar briquettes with clay binder were as follows: the calorific values ranged from 17140-18336 kJ/kg; the water boiling time ranged from 45-74 (min); the burning rate ranged from 2.88-4.47 (g/min). The total emission of CO, CO2 and PM2.5 produced during combustion ranged from 38.86-56.59 (g), 128-228(g), and 702-1092(mg), respectively. The results of the developed combined biochar briquettes with gum Arabic binder calorific values ranged from 18053-18665 kJ/kg; water boiling time ranged from 42-50 (min); the burning rate ranged from 3.89-4.93 (g/min). The total emission of CO, CO2 produced during combustion ranged from 33.04-66.68(g), 48-229(g) respectively, while the PM2.5 alternated from 1037-1500 (mg). The results showed that the calorific values of the developed combined biochar briquettes with hybrid binder ranged from 17404-18232 kJ/kg; water boiling time ranged from 40-56 (min); burning rate ranged from 3.59-5.12(g/min). The total emission of CO, CO2 and PM2.5 produced during combustion, ranged from 32.57 - 45.12(g), 98-218(g), and 599 -1385 (mg), respectively. From the result obtained, a hybrid binder is can therefore be considered a suitable alternative to binders. This study equally showed that the hybrid binder had reduced boiling time, higher burning rate, higher compressive strength and low fuel consumption. Therefore this study recommends the use of the briquettes produced from combined biochars with gum Arabic binder and a hybrid binder.