A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering

Thesis (M.Eng.) - Asian Institute of Technology

Fluidi7.ed Red Combustion System is wide ly regarded as one of the most promising techniques for huming low grade fuels and also t.o reduce 1he emission of litmospheri c pollutantr.. such as NC\ and so2 , released during i:he combustion. This ~ys m shows many advantages over th e conventional combustion systems such as, higl1 comhuslion effic.:i ency, effici ent pollution contrnl and it.s fl exihility to bum prnct.ically any cnmhusti hle mal.erial. In the present work, experiments were performed to study the combustion of two low grade fuels e.g. black liquor and pit h (wasl.e materials of pulp and paper industry), as fuelr... The ex riment~~ on the hlack Ji4uor cnmhuscinn, in fluidized and spouted beds, had shown the agglorneralion problem of I.he hed matedal due t.o characteristics of the fuel. Good results were achieved in case of pith combustion hy using the Jluidized an d spouted he el comhust.ion sysl.ems. The combustion effi ciency in 1his case was found in the range of 80- 94%. The present work also studied the pyrolysis kinetics of black liquor and main components of biomass (cellulose, xylan and lignin). Them1ogravime tric analysis was canied oll1 10 study the r.hermal behavior of these mate1fals. Tt was fo und, during this study that hl11ck liquor pyrolysis is a lwo st.age process. H was presumed that the lignin portion was pyrolyzed during I.he first stage. This was confirmed when the values of activation energy and temperature range of the first. st.age of black liquor pyrolysis was compared with those of lignin py roJysis.