FESEABILITY STUDY OF A PYROLYSIS CONVERSION PLANT FOR HEAT AND POWER PRODUCTION WITH SEWAGE SLUDGE AS FEEDSTOCK - MASS AND ENERGY BALANCE

The present work aimed to evaluate the feasibility of a waste to energy plant, at a global glance, considering not only the conversion step but also all the required installations before and after the conversion process. The process conditions have been fixed to maximize the syngas production (process temperature: 850 degrees C, residence time: 20 minutes). In the present work a feasibility study of a waste to energy plant feed with sewage sludge is reported. 16000 t/years have been considered as input material. The waste material has to be dried to maximize the plant efficiency. The apparatus for feedstock preparation (drying unit) has been considered from mass balance, energetic and economic point of view. The plant has been equipped with commercial furniture to assure a realistic estimation of plant efficiency and energy consumptions. The byproducts of pyrolysis process are: syngas 48 %, liquid 16% (oil) and char 36%. The syngas average heating value is 16.5 MJ/Nm(3). A layout of a possible plant configuration has been design to estimate the required installation area. A business plan with the return investment costs has also been reported. The impact of the feedstock pre-treatment unit and the amount of byproducts generated has been also considered.