(83c) Assessing the Technical Feasibility of Steam Hydrogasification of Agriculture-Derived Wastes for Renewable Fuel Production in the Leading Agriculture Region

California is the largest producer of agricultural products in the nation. In particular, the Central Valley of California is one of the world's most productive agricultural regions and many Central Valley’s counties are at the top of the nation's agriculture producing counties. Hence, a huge number of agricultural wastes such as corn stover, orchard pruning, and manure is generated regionally every year. However, conventional treatment methods such as open burning and land application lead to air quality issues and contamination of ground water. Additionally, the Central Valley is home to the largest concentration of dairies in California, which has the largest milk producer in the United States. Though industrial wastewater treatment facilities were established for treating regional dairy wastewater, the high strength of dairy wastewater influent is still challenging to traditional treatment processes. Therefore, sustainable methods for processing these agriculture-derived waste streams are highly demanded. Steam hydrogasification reaction based process is an advanced and self-sustainable technology that can convert high moisture content feedstock (e.g., commingled orchard pruning and dairy wastewater) into renewable energy and fuels without costly drying process. In this study, the availability of various agricultural waste streams was assessed, and the technical feasibility of steam hydrogasification of dairy wastewater and other agricultural waste was evaluated experimentally. The preliminary results showed that over 15 million bone dry tons of agricultural wastes are generated in the Central Valley annually, which occupy over 60% of total gross agricultural wastes in California. Also, the dairy wastewater amount is sufficient to be used and mixed with most agricultural waste streams in the Valley. The experimental data showed that steam hydrogasification of dairy wastewater and different agricultural waste led to high carbon conversion (>90%) and desired syngas composition (e.g., sufficient hydrogen for internal recycle use, high methane yield) for further downstream upgrading to final renewable fuel products such as synthetic natural gas.