A Study on Agglomeration Behaviour of Cotton Stalk Under Fluidized Bed Conditions

Abstract

In this work, agglomeration behaviour of cotton stalk under conditions similar to fluidized bed has been studied. Fuel samples of cotton stalk, bed material (silica sand), bed ash and agglomerate were collected from 7.5 MW FBC-based thermal power plant located at Sri Muktsar Sahib, Punjab, India. Samples of cotton stalk ash mixed with silica sand are heated in a perforated bowl at three different temperatures viz. 700, 800 and 900 ℃ in a muffle furnace. SEM images of the samples showed that ash viscosity decreases with increase in temperature leading to increase in ash coated sand particle stickiness. Formation of gas holes and cracks was observed at surfaces due to release of gaseous products. On completion of combustion, solidification of low-melting-point alkali silicates takes place leading to the formation of agglomerates. Agglomeration index of cotton stalk is found to be 4.31, indicating high agglomeration tendency of cotton stalk. An agglomeration mechanism has also been proposed for cotton stalk.