Current demand for wood biomass and plastic composite materials is increasing year by year. At the same time, mixed wastes that include plastics and wood materials continue to be generated from waste treatment streams without efficient, economical recycling and utilization of these mixtures via separation. It is crucial, therefore, that treatment systems not requiring separation are developed to address the situation. The future of recycling in Japan must look ahead with an aim to not only increase the amount of recycling being done, but also to improve the quality of products being recovered. To realize this, production of “circulative resources, ” such as feedstocks used in the chemical industry and high quality fuel from complicated mixed wastes, must be achieved. This paper first summarizes the current situation with regard to plastic recycling and utilization of woody biomass through thermochemical processes such as pyrolysis, incineration and gasification. With examples showing the effectiveness of co-pyrolysis treatments, the paper goes on to introduce some of the research being conducted by the authors on co-pyrolysis of wood biomass/plastic mixtures and syngas production from these mixtures.

View full abstract

Biomass gasification and catalytic liquid fuel (Biomass-To-Liquid : BTL) synthesis is a promising process not only for energy but also for chemical applications. It is being advocated that BTL be widely introduced by the Japanese government in the near future, at least before 2030. BTL synthesis is currently at the R & D stage and its use is expected to accelerate within Japan. For example, the R & D budget for BTL will be increased by 5 times in fiscal year 2017. We have been studying entrained-flow type biomass gasification because of advantages that make it suitable for BTL synthesis. In this paper, we introduce and give an overview of our joint research projects being conducted among several companies and one university, organized by the New Energy and Industrial Technology Development Organization (NEDO). This research focuses on methanol synthesis at a 2-ton/day scale test plant and bio-jet fuel synthesis using a pilot plant.

View full abstract

The rebuilding of the municipal solid waste disposal facility has been a pressing issue in Machida City. Following discussions on future perspectives for general waste disposal held between the municipal government and citizens, two basic plans were formulated: one plan proposed changing municipal solid waste into usable resources and the other recommended construction of a facility for resource recycling. A method known as DBO (Design Build Operate) was adopted for the construction and management of the new facility, this advocates that building be done on a public basis while operation is taken up by the private sector. The execution policy outlining construction and management for such an energy recovery facility was publicly announced in Machida City in January 2016 and the contract for this project was concluded with entrepreneurs in December 2016. Machida City has been promoting the slogan, “Refuse products that end up in the waste stream・No incineration・No landfill” as its basic philosophy and motto since 2006. Over the past 10 years, the municipality and citizens have worked hand-in-hand to incorporate renewable energy sources and reduce negative impacts to the environment while also utilizing this facility as their municipal general waste disposing facility.

View full abstract

A food waste recycling system was constructed using a small-scale methane fermentation system that incorporates hot spring heat. Local people provide the food waste and reap the benefits of the rich liquid byproduct. Biogas produced from food waste using methane fermentation is being used to boil water for the Ene Café METHANE. Instead of money, customers make payment in food waste to drink a cup of tea. The system has gained a following, now with over 1900 club members participating. Community members collect their organic food waste and utilize the liquid fertilizer (i.e. methane fermentation-digested liquid) generated as a byproduct of the system. The system at Ene Café METHANE is a completely interdependent food recycling system that makes customers happy because they can recycle their food waste while enjoying the company of fellow locals over a cup of tea. It has also been developed as a tourism resource and is creating stronger face-to-face communication within the community. This unique system is introduced here, along with a description of possibilities for its future development.

View full abstract

Utilization of biomass and effective use of its energy are important issues from the viewpoint of preventing global warming (reducing greenhouse gases) and resource recycling. Generation by biomass-based waste is expected to become a stable power source that is not affected by weather and other such factors. In order to disseminate compact, dispersed power generation using biomass with regional characteristics, high efficiency power generation technology is required for small- and medium-sized facilities. Power generation using a gas engine is not influenced by facility size. Fluidized bed gasification is a technology expected to produce gaseous fuel for gas engines and is considered important in the accumulation of information to influence material and gasification conditions on synthesized gas compositions. Unfortunately, till now, realization of MSW disposal facilities generating electricity using gasification and gas engines is still limited. A woody biomass power generation facility that uses gasification combustion has, however, been running stably since April 2016. Operating at a low total air ratio under 1.2, boiler efficiency has exceeded 90 % and a power generation efficiency rate of 29 % has been made achieved.

View full abstract

The outline of basic characteristics, production equipment, demonstration experiments and future prospects of Biocoke (BIC) are described in this paper. BIC, devised by Ida et al. in 2006, is a new type of sold biofuel developed to replace coal-coke. BIC has several positive features, including high apparent density, high compression strength, slow combustion rate, long-term safety storage ability and high yields of mass and energy. These qualities make BIC functional as a biofuel, enabling gas and liquid to flow within a furnace in a high temperature environment. The production method apparatus for BIC was upgraded from batch operation to a continuous operating production method in 2012, which has contributed even further to an increased production rate and a reduction in energy consumption. From the results of the demonstration experiments that have been conducted since 2008, it was confirmed that BIC can be utilized not only in a cupola or a high-temperature gasifying and direct melting furnace, but also in agricultural facilities for heating. It is expected that further investigations into BIC reform will increase the substitution rate of coal-coke and further spread utilization of BIC into the world, as well as in Japan.

View full abstract

Municipal waste incineration facilities in Japan often use gasification melting furnaces due to their high environmental performance and ash volume reduction. This project tests bio-coke made from various types of biomass, fed into a furnace for several months as a substitute for coal coke. Bio-coke is considered to be a carbon-neutral fuel and has been verified to reduce CO₂ emissions by at least 25 %, as compared to conventional fuel.
　The project aims to achieve four objectives : (1) steady collection of biomass in Yokote City, Akita Prefecture (mainly rice husks and bark, but their availability varies with harvest and snow seasons, respectively, so various types of biomass will be collected to provide a steady year-round supply of mixed feedstock); (2) development of effective and economic technology to produce bio-coke from mixed feedstock; (3) long-term demonstration of operations using bio-coke at Morioka/Shiwa District Environmental Facilities Association; and (4) investigation of the applicability of bio-coke from mixed feedstock in other industries.

View full abstract