Fundamental study on incineration of woody waste including seawater using the two-stage combustion method

Abstract

The objective of this study is to establish a method of direct combustion that allows safe and effective incineration of difficult-to-process woody waste as well as its utilization as fuel. A tremendous amount of debris including woody waste was washed into the sea by the tsunami of the Great East Japan Earthquake in 2011, and still remains on the coastal seabed. In order to examine the feasibility and effectiveness of incineration of the woody debris containing seawater, combustion experiments are conducted using a small combustor by applying the two-stage combustion method which we developed for woody biomass. Simulated wastes with three different moisture contents (13, 22, 38 %) are prepared by saturating woody chips with artificial seawater. The experiments confirm that the two-stage combustion method is applicable to the combustion of the woody waste containing seawater. In addition, it is clarified that combustion temperature could be widely controlled by changing the amount of air in the range of about 860 to 1250 K in the pyrolytic combustion process and about 820 to 1240 K in the surface combustion process. The results indicate that the two-stage combustion method is effective to reduce salt content in combustion gas, and that a large part of contained salt could be recovered as a residue after incineration. It is also revealed that combustion temperature is an important factor influencing the generation of hydrogen chloride.

Keywords

• solid combustion
• woody waste
• seawater
• two-stage combustion method