High quality syngas production from microwave pyrolysis of rice husk with char-supported metallic catalysts

• RHC-supported metallic catalysts had good microwave absorption capability.
• Ni/RHC catalyst presented most effective effects on gas production.
• Ni/RHC and Fe/RHC catalysts played pivotal roles in tar conversion.

This study aimed to obtain the maximum possible gas yield and the high quality syngas production from microwave pyrolysis of rice husk with rice husk char and rice husk char-supported metallic (Ni, Fe and Cu) catalysts. The rice husk char-supported metallic catalysts had developed pore structure and catalytic activity for gas productions and tar conversion. The temperature-rising characteristic, product yields, properties of gas products and tar conversion mechanisms were investigated. It was found that three rice husk char-supported metallic catalysts improved the microwave absorption capability and increased heating rate and final temperature. Rice husk char-supported Ni catalyst presented most effective effects on gas production, e.g. the gas yield is 53.9%, and the volume concentration of desired syngas is 69.96%. Rice husk char-supported Ni and Fe catalysts played pivotal roles in tar conversion that less heavy compounds can be detected along with the reduction of organic compound number.