Study on the combustion properties of bio-coal briquette blends of cassava stalk

Abstract

This study was carried out to investigate the properties of bio-coal briquette produced from blending cassava stalk and coal. The cassava stalk and coal lumps were carbonized at 160 ^oC, pulverized and used to produce biocoal briquettes of 10 %, 20 %, 30 %, 40 %, 50 %, 60 %,70 %, 80 %, 90 % and 100 % biomasses. The briquettes were produced mechanically using a manual briquetting machine with force and compression pressure of 276.36 N and 31.67 N/m² respectively using starch as a binder while Ca(OH₂) was the desulphurizing agent. Proximate analyses of raw cassava stalk showed ash content (5.48 %), volatile matter (45.72 %), fixed carbon (25.34 %), moisture content (23.46 %) and calorific value (25834 kJ/kg). For the raw coal, the proximate analyses results are moisture content of (3.25 %), volatile matter of (20.12 %), ash content of (10.12 %) and calorific value of (29573.13 kJ/kg). The briquettes were sun-dried for five days and analyzed. For the briquettes produced, the 40% bio-coal briquette sample with values; ash content (25.13 %), fixed carbon (41.36 %), moisture content (3.36%), volatile matter (30.15 %), calorific value (25898.18 kJ/kg), water boiling test (2.98 min), burning time (22.79 g/min), ignition time (36.68 s) and compressive strength (10.78 N/mm³) showed improved combustible qualities.

Keywords: briquette, cassava stalk, binder, blend, bio-coal, fuel