Development of pyrolysis based process for synthetic fuel production from biowaste

Abstract

Pyrolysis is a thermal process without oxygen. Pyrolysis of biomass produces three main products: biooils, biogas and biochar. Depending on the process conditions, they appear in different proportions. High biochar yield will be achieved if low temperature and low heating rate are carried out. One of the main disadvantages of pyrolysis is the formation of dioxins and furans which are very toxic. Their formation also depends on the conditions of the process. In this paper, the aim is to optimize the conditions of the pyrolysis process in laboratory scale in order to achieve the maximum yield of biochar and the minimal production of dioxins and furans. For this purpose, oak sawdust was used as biomass. Oak sawdust was previously characterized by ICP-MS and CHNS analyzes and its calorific value was determined. Pyrolysis processes were performed at three temperatures: 350, 550 and 750 0. The yields of the main products were measured gravimetrically, while the main gaseous by-products of pyrolysis were measured by GC-MS technique. From the obtained results, it can be concluded that the highest yield of biochar is at the lowest temperature; with lowest yield of syn-gas. Unlike the lowest temperature, at the highest temperature, almost no biochar is formed with almost 90 % of produced syn-gas and in that case GC- MS analysis shows that there are less unwanted by-products.