Thermodynamic analysis of pyrolysis of olive mill waste water sludge in fluidized bed reactor

摘要

Energy production from fossil fuels is a conventional method which has negative impacts on environment and puts a heavy burden on economy of a country. The developed countries are focusing more on renewable energy sources and reducing their dependency on fossil fuels. Among other renewable sources of energy, biomass is a reasonable source of energy because it also solves the problem of disposal of waste products. Fast pyrolysis is a high temperature thermochemical conversion process widely used for production of bio oil from biomass. Pyrolysis model of olive mill waste water sludge is developed in Aspen Plus based upon the experimental results. Pyrolysis of olive mill waste water takes place at 450°C in a fluidized bed reactor. The products are passed through cyclone at 350^°C for removal of biochar. Bio oil vapors and non-condensable gases are passed through a series of condensers. A heat exchanger carrying water is employed after cyclone to condense the bio oil vapors at 90°C. Cooling water is heated upto 67°C in the heat exchanger which is a suitable temperature to drive an adsorption machine. This adsorption machine is used to condense water vapors at 10°C. The exergy analysis of the process shows that a net heat transfer of 30 W takes place in the first condenser. Overall exergy efficiency of pyrolysis olive mill waste water sludge is about 83% taking into account all products. High efficiency suggests that pyrolysis is a very efficient process for production of bio-oils.