Abstract
According to the statistics in 2014, 39.7 million ton of municipal solid waste (MSW) were incinerated in our country, and 4.3 million ton of incineration residue generated. Aluminum (Al) is contained in incineration residue, and it is known that Al contributes to generation of hydrogen gas, but little is known about quantitative information about detailed Al source in MSW and material flow of Al in MSW has not been clarified. In addition, economic and environmental assessment about a hydrogen recovery system from incineration residue has not been accomplished. This paper attempted to apply material flow analysis (MFA) and life cycle assessment (LCA) on a system of hydrogen recovery from incineration residue in order to evaluate its environmental and economic efficiency. Specifically, this study focused on was Clean Park Seibu of Fukuoka city as a target facility, Al flow in municipal waste treatment, life cycle cost and life cycle CO2 emission of hydrogen recovery system were estimated.
A result of material flow analysis on Al in 2015 showed that the amount of Al contained in incineration residue was 686t. In this amount of Al, 90% came from combustible waste and 10% came from incombustible waste. The amount of hydrogen gas recovery of hydrogen recovery system was 15, 435Nm3 and life cycle cost of hydrogen recovery system was 4.25million yen/year. In life cycle cost, 83 % came from initial cost and 17% came from running cost. According to the results of the amount of hydrogen gas recovery and life cycle cost of hydrogen recovery system, hydrogen production cost was 275 yen/Nm3. In order to meet a standard of hydrogen sales price 103-113yen/Nm3, it is necessary to increase flow rate of hydrogen gas in 8Nm3/h. And also, it was revealed that the amount of CO2 emission of hydrogen recovery system and unit CO2 emission were 21.0t-CO2/year and 1.36kg-CO2/Nm3 respectively.
