Abstract
The aim of the present work is to investigate the chemical and physical properties of the grass psecies Phragmites australis (known also as common reed) and to characterize the products derived from its pyrolysis. Calorimetric analysis of different reed samples highlighted an interesting heating value of about 17 MJ/kg on a dry basis. Nevertheless, this feedstock has been found to be characterized by considerable ash content and rather low ash melting temperatures. These aspects are essential for the correct design of a possible treatment plant for the thermochemical conversion of herbaceous biomass. Furthermore, reed thermal behavior has been assessed by means of advanced thermal analysis, consisting of thermogravimetric analysis (TG) coupled with the simultaneous analysis of the evolved gases by means of gas chromatography/mass spectrometry (GC-MS) and infrared spectroscopy (FT- IR). Several pyrolysis tests have been then performed in a bench scale pyrolysis apparatus, investigating different process temperatures (between 300°C and 700°C) with an heating rates of 50°C min-1. In each test, the condensable fraction (tar) was collected according to the technical standard CEN/TS 15439 and analyzed through gas chromatography in order to detect the content of polycyclic aromatic hydrocarbons (PAHs). Moreover, the permanent gases were analyzed on-line by means of a microGC system. A detailed economic analysis is required to give a reliable assessment of the applicability of reed in thermochemical conversion plant. However, a proper feasibility analysis cannot be performed without taking into account the physical-chemical characteristics of such biomass, its thermal behavior and the characterization of the process products and by-products. The results of this work are crucial for this purpose.