Mitsubishi Heavy Industries, Ltd. (MHI) has successfully developed technology to produce cellulosic ethanol for automobile fuel satisfying the standards of the Japanese Automotive Standards Organization (JASO) from feedstocks such as rice straw and barley straw.
Verification of the technology was conducted as a joint project involving the government, academia, and the agricultural and industrial sectors in Hyogo Prefecture, supported by the Ministry of Agriculture, Forestry and Fisheries (MAFF), to study effective utilization of lignocellulose. During the technological verification at a demonstration plant, the estimated fuel cost required for commercial-scale ethanol production was also confirmed to achieve the targeted goal.
Going forward MHI will endeavor to develop the results of the project into early commercialization of bio-refinery technology in cooperation with companies and organizations concerned.
The demonstration project to produce cellulosic bioethanol has been under way since 2008 jointly with the Hyogo Prefectural Government, the Hyogo Environmental Advancement Association (HEAA) and other entities. MHI jointly with Hakutsuru Sake Brewing Co., Ltd. and Kansai Chemical Engineering Co., Ltd. was responsible for verification of the bioethanol production processes.
Initially, each of the three participating companies took charge of specific areas based on their expertise and conducted verification testing at their own research facility. Starting in December 2009 the entire process to produce ethanol from lignocellulose was verified at a demonstration plant built specifically for the project at MHI’s Futami Plant in Hyogo. Rice and barley straws, the feedstocks, were provided by a local farmers association. HEAA, the Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, and Mitsubishi Agricultural Machinery Co., Ltd. were responsible for the verification of effective technologies relating to feedstock collection, transportation and storage.
Among the various production processes, MHI was responsible for preprocessing and saccharification; Hakutsuru Sake Brewing for fermentation; and Kansai Chemical Engineering for distillation and dehydration.
For preprocessing and saccharification, MHI adopted a hydrothermal treatment system that enables continuous processing of feedstocks; MHI made improvements to the technologies, which were jointly developed with the New Energy and Industrial Technology Development Organization (NEDO). The new system can produce the sugar component more efficiently than by conventional methods using only hot compressed water and enzyme, MHI says. The demonstration testing focused on the system’s performance stability and continuous operability and on optimization of the amount of enzyme to be applied.
In conjunction with the fermentation process, Hakutsuru Sake Brewing, in cooperation with Kobe University, established a technology to convert sugar originating from rice and barley straws into ethanol by use of yeasts. The yeasts are selected from those actually in use or those bred with non genetically modified organism (Non-GMO) technology.
Kansai Chemical Engineering verified distillation and dehydration technologies for producing bioethanol that satisfies automotive fuel standards. The technologies involve use of a new type of distillation column developed by the company which enables longer continuous operation than conventional systems, and a liquid phase adsorption type dehydration unit that enables processing with less energy than existing gas phase types.
The results of these various tests confirmed that biofuel satisfying JASO standards can be produced continuously, and they validated optimal operation conditions when using rice and barley straws as feedstocks. At the same time, based on the verification results, the bioethanol production cost was estimated for a commercial-scale plant to be built in Hyogo Prefecture. It was confirmed that total running costs from collection and transportation of feedstocks to ethanol production can be achieved below the target of ¥90 per liter ($4.17/gallon US).
The technology for extracting sugar from lignocellulose verified by MHI has been drawing attention not only for its feasible application to ethanol production but also as a technology applicable to the production of basic material for bio-plastics.
MHI now plans to make the demonstration plant used in this project available to other business operators in Japan and abroad who are developing applications of feedstock material other than straw and targeting production of non-ethanol products. Going forward the company will continue its pursuit of early establishment of technologies for commercial-scale bio-refinery, including bioethanol, and it will seek order receipts for both experimental and commercial systems based on its proprietary technologies in cooperation with companies and organizations concerned.