EXPERIMENTAL-DETERMINATION OF BED AGGLOMERATION TENDENCIES OF SOME COMMON AGRICULTURAL RESIDUES IN FLUIDIZED-BED COMBUSTION AND GASIFICATION

Ever increasing energy demand and the polluting nature of existing fos sil fuel energy sources demonstrate the need for other non-polluting a nd renewable sources of energy. The agricultural residues available in abundance in many countries can be used for power generation. The flu idized bed technology seems to be suitable for converting a wide range of agricultural residues into energy, due to its inherent advantages of fuel flexibility, low operating temperature and isothermal operatin g condition. The major ash-related problem encountered in fluidized be ds is bed agglomeration which, in the worst case, may result in total defluidization and unscheduled downtime. The initial agglomeration tem perature for some common tropical agricultural residues were experimen tally determined by using a newly developed method based on the contro lled fluidized bed agglomeration test. The agricultural residues chose n for the study were rice husk, bagasse, cane trash and olive flesh. T he results showed that the initial agglomeration temperatures were les s than the initial deformation temperature predicted by the ASTM stand ard ash fusion tests for all fuels considered. The initial agglomerati on temperatures of rice husk and bagasse were more than 1000 degrees C . The agglomeration of cane trash and olive flesh was encountered at r elatively low temperatures and their initial agglomeration temperature s in gasification were lower than those in combustion with both bed ma terials. The use of lime as bed material instead of quartz improved th e agglomeration temperature of cane trash and olive flesh in combustio n and decreased the same in gasification. The results indicate that ri ce husk and bagasse can be used in the fluidized bed for energy genera tion since their agglomeration temperatures are sufficiently high. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.