Improvement of bio-crude oil properties via co-pyrolysis of pine sawdust and waste polystyrene foam.

Conversion technology of solid biomass to liquid fuel, named bio-crude oil, has been researched widely for the production of renewable energy to replace fossil fuel oil. As the result of many admirable researches, fast pyrolysis technology for bio-crude oil production is close to commercialization. However, bio-crude oil has unsatisfactory properties compared to general petroleum oil, for instance, low heating value, high water content, and high viscosity. In this study, pine sawdust (SD) biomass was co-pyrolyzed with waste polystyrene foam (WPSF), which was expected to improve the bio-crude oil quality due to high heating value and non-oxygen composition of polystyrene. The co-pyrolysis experiment was conducted in a bubbling fluidized bed reactor under the following conditions: temperature of 500 °C which was chosen based on the results from thermogravimetric analysis of SD and WPSF, nitrogen flow rate of 20-25 L/min., and feeding rate of 200 g/hr. Various mixing ratios of SD/WPSF by weight percentage were tested as follows: 100/0, 95/5, 90/10, 85/15, 80/20, 75/25, 70/30, 60/40, 50/50, 25/75, 0/100. Experimental results showed that in case of only SD feeding the bio-crude oil yield and higher heating value (HHV) were 48.83 wt% and 17.81 MJ/kg respectively. By contrast, oil yield and HHV in case of 25% SD with 75% WPSF mixture were 63.31 wt% and 39.65 MJ/kg respectively. Additional analysis showed that water content, and acetic acid concentration of bio-crude oil from co-pyrolysis of SD/WPSF mixture were decreased almost proportionally with the increasing WPSF ratio. Furthermore, measured values of water content, and acetic acid concentration were lower than the calculated values by linear interpolation, which means that the synergistic effect between SD and WPSF was achieved during the co-pyrolysis. In conclusion, co-pyrolysis of SD and WPSF was found as a promising solution to improve bio-crude oil quality. With this technology, the industrial growth of bio-crude oil area is expected as well as waste plastic.

Characterization of Korean solid recovered fuels (SRFs): an analysis and comparison of SRFs.

To date, Korea has used four species of solid recovered fuels (SRFs) which have been certified by the Environmental Ministry of Korea: refuse-derived fuel (RDF), refused plastic fuel (RPF), tyre-derived fuel (TDF), and wood chip fuel (WCF). These fuels have been used in many industrial boilers. In this study, seven regulatory properties associated with each of the four species: particle size, moisture and ash content, lower heating value (LHV), total chlorine, sulfur, and heavy metals content (Pb, As, Cd, Hg, Cr) were analysed. These properties are the main regulation criteria for the usage and transfer of SRFs in Korea. Different properties of each SRF were identified on the basis of data collected over the last 3 years in Korea, and the manufacturing process problem associated with the production of SRFs were considered. It was found that the high moisture content of SRFs (especially WCF) could directly lead to the low LHV of SRFs and that the poor screening and sorting of raw materials could cause defective SRF products with high ash or chlorine contents. The information obtained from this study could contribute to the manufacturing of SRF with good quality.