Comparative Thermal Analysis of the Properties of Coal and Corn Cob Briquettes

Abstract

The work involved the production of smokeless briquettes of various compositions from coal and corn cob using CaSO4 and starch as binders, while Ca(OH2) was used as desulphurizing agent. The briquettes were produced in the following ratio of coal and rice husk such as 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100 respectively. The proximate analyses of the raw coal sample yielded the following: ash content 12.56%, moisture content 7.03%, volatile matter 39.21%, fixed carbon 41.2% and calorific value 117.18 KJ/g. The corn cob gave the following values, ash content 12.56%, moisture content 7.03%, volatile matter 39.21%, fixed carbon 41.2% and calorific value 61.46 KJ/g. The prepared briquettes were sun dried for seven days, subjected to various tests to assess their fuel quality. Of the briquettes produced, the 80% coal: 20% corn cob briquettes produced using starch as binder had the following values; ash content 21.70%, fixed carbon 45.01%, moisture content 2.87%, density 0.482 g/cm 3 , volatile matter 30.42%, porosity index 40.12%, calorific value 153.23 KJ/g, water boiling test 1.65 minutes, burning time 24.42 minutes, ignition time 41.22 seconds and sulphur content 6.05%. For briquettes produced with CaSO4 as binder, 80% coal: 20% corn cob had the following values; ash content 27.69 %, fixed carbon 41.63 %, moisture content 2.77 %, density 0.503 g/cm 3 , volatile matter 27.91 %, porosity index 41.11 %, calorific value 134.46 KJ/g, water boiling test 1.71 mins, ignition time 41.40 secs, burning time 25.91 mins and sulphur content 7.42 %. The briquettes showed improved properties but with regards to combustible property, the briquettes made using starch as binder do have better qualities than those of produced with CaSO4 as binder.