Production and Characterization of Biomass Briquettes from Tannery Solid Waste

Abstract

Abstract:The tannery industry is renowned for the huge amount of toxic solid and liquid waste generated from the cleaning, fleshing, splitting, tanning, shaving and buffing of raw materials. Biomass briquettes are a proven way of generating energy from waste. This study investigates the development and characterization of biomass briquettes from tannery solid wastes (TSWs). TSWs, which comprise hair, flesh, chrome shavings and buffing dust, were collected from a tannery in Kano, Nigeria, to formulate and characterize six briquettes. Scanning electron microscopy and proximate analysis were carried out on the samples. The six briquettes, comprising varying ratios of hair, flesh, chrome shavings and buffing dust, were molded and characterized. Thermal efficiency, durability and compressive strength, among other properties, were determined for the six briquette formulations. The briquettes developed had calorific values between 18.632 and 24.101 MJ/kg. Durability of the briquettes ranged from 98.12% to 99.77%. The energy values were within the range of 17.462-24.101 MJ/kg, which was comparable to other fuel sources such as sub-bituminous coal (20.000-24.730 MJ/kg). This study shows that TSWs can be used for fuel briquette production, which is a source of sustainable energy generation. It is environmentally friendly, cost effective and affordable compared to fossil fuel.

Potential of Briquetting as a Waste-Management Option for Handling Market-Generated Vegetable Waste in Port Harcourt, Nigeria

“…The lower moisture content of the torrefied briquettes compared to the sun-dried ones could be explained by the removal of free and chemically bonded moisture resident in the residues with increasing temperature [38]. The lower moisture content of the sun-dried carrot briquettes (3.53-6.13%) compared to the sun-dried cabbage briquettes (4.61-8.47%) agrees with the finding of Onukak et al [25] and may be a result of the levels of moisture in the waste materials. Carrot residues had lower moisture (48.5%) than cabbage residues (84.9%).…”

“…The lower moisture levels of the briquettes are an advantage in the sense that energy will not be utilized to exhume much moisture during combustion. Also, a damp fuel will lead to the excessive emission of fumes and a risk of explosion [25]. The lower moisture content of the torrefied briquettes compared to the sun-dried ones could be explained by the removal of free and chemically bonded moisture resident in the residues with increasing temperature [38].…”

“…The briquettes made from sun-dried cabbage residues had the shortest ignition time of all the briquette types because of their larger particle sizes [25]. The larger particle sizes offered more pronounced pore spaces for the easy percolation of oxygen and the outflow of combustion products during combustion [25,37]. The increase in the time taken to ignite this particular briquette type (Figure 5a) with an increase in the percentage of paper could be due to the increase in the concentration of biomass in those briquette types [16].…”

“…It involved boiling an equal volume (100 cm 3 ) of water with a fixed mass (100 g) of the various briquette types as reported by Onuegbu et al [27], using a typical local charcoal stove. During this test, the smoke evolution level was observed and other properties including ignition time, boiling time and burning rate of the briquettes were measured, as reported by Onukak et al [25] and Onuegbu et al [27].…”

“…The percentage difference between these two weights gave an estimate of the moisture content of the waste materials. The moisture content (dry basis) of the briquettes was determined using the oven-dry method as carried out by Onukak et al [25] using three samples of briquettes from each treatment. …”