Power Generation from Bamboo with Hybrid Kiln: R&D and Future

Abstract

All plants on Earth are composed of polymeric organic carbon (OC), a compound synthesized by nature from atmospheric carbon dioxide (CO₂, hereafter referred to as atmospheric carbon) and water. Fossil fuels, which have been the primary energy source essential for human survival, are made from OC synthesized from atmospheric carbon from geological times. The use of fossil fuels results in the release of geological atmospheric carbon dioxide into the present-day atmosphere, which contributes to global warming. To avoid global warming, the world has pledged to achieve net-zero carbon dioxide emissions into the atmosphere by 2050 (2015 Paris Agreement).

Energy alternatives to fossil fuels such as the sun, wind, and plants are primarily classified into natural sources. Of these, plant energy is superior to solar and wind energy in that it can be supplied reliably 24 hours a day. The challenges for plant energy lie in the stable procurement of raw materials and the development of technologies for decomposing and reforming them.

The present authors focused on bamboo, which has particularly excellent land productivity per area, as a raw material plant. To avoid clinker formation caused by high potassium (K) content of bamboo, it is strictly required to control the temperature below the volatilization point of potassium compounds. While satisfying this requirement, the present study aims to achieve the thermochemical conditions necessary for efficient steam reforming (typically above 900℃). To this end, a low-temperature reforming technology using catalyst-supported char (at 750℃ or lower) has been developed. The paper describes the development process and future prospects of a power supply business utilizing this technology through the use of a hybrid kiln (an externally heated horizontal rotary kiln with an internal gas-solid contact structure) developed by the authors as a pyrolysis and reforming gasification device.