Partial replacement of coal with paddy straw pellets as fuel in brick kilns

Abstract

Rice is a major crop cultivated in Northern India. The open burning of stubble left after harvesting of this crop has severe impacts on environment despite various interventions for its in situ and ex situ management; large quantities of paddy straw continue to be burnt in open fields. Thus, there is pressing need to establish techno-economically viable applications for paddy straw. In the present study, paddy straw in pellet form was utilized as partial replacement of coal in brick kiln industry. The trials were conducted with combination of different ratios of paddy straws pellets (PSP), and coal is used in ratios 10:90, 15:85, 20:80, and 30:70. After mixing the PSP with coal, this mixture was fed in the feed holes of the brick kilns and their effectiveness for achieving the required temperature range, and energy for vitrification/baking of clay bricks was assessed. After conducting the trials, the optimum PS-based pellet to coal ratio could be obtained without any modification in the configuration of the kiln or process. Thus, after the investigation, it has been found that the coal can be replaced partially with 20% PSP. Further, the stack emission monitoring showed reduction suspended particulate matter (SPM) and sulfur dioxide (SO₂) emissions. The values of brick quality test presents that the PSP co-fired bricks fall under Class 15 standard as per the IS code 1077 (1992): Common Burnt Clay Building Bricks-Specification.