Low-Carbon Fertilizer Production from Tropical Biomass Gasification

Summary: Address the problem of high greenhouse gas emissions and high national and economic security risk from imported fossil-derived fertilizers, by manufacturing low-greenhouse gas organic and potash fertilizers from tropical biomass and locally-sourced organic wastes. We will then demonstrate performance compared to imported fertilizers in physical on-farm trials. The Russian invasion of Ukraine in February 2022 and subsequent 30% spike in fertilizer prices globally, highlighted the direct links between fossil natural gas, fertilizer production, and food security to U.S. national and economic security. Russia is the worldĺs largest exporter of fertilizer with 21% global market share in potash fertilizers. In addition, nitrogen fertilizer application produces over 74.2% of U.S. agricultural greenhouse gas (GHG) emissions, and this does not even include the GHG emissions from the fossil natural gas used to make the fertilizer. We are developing an integrated gasification process to convert cellulosic and woody waste such as ôdirtyö wood from construction and demolition debris (C&D) and greenwaste from invasive plants into renewable natural gas and hydrogen. Through this work, we discovered that the ash from this ôcleanö biomass creates an opportunity to re-use the ash and its nutrients as an organic and potash fertilizer. Our simple estimates of the carbon intensity showed a lifecycle GHG reduction over 97% below traditional fossil fuel fertilizer inputs. Over 25% of that has been mineralized carbon, providing additional GHG benefits through permanent carbon sequestration. In our home market of Hawaii, over 99% of the food, energy, and fertilizer are imported; the municipal landfill in every county has less than 10 years of life left; and land and fresh water resources are very limited. Fertilizer costs are the highest operating expense for farmers in Hawaii after labor, and fertilizer in Hawaii typically costs 40 to 100% more than the U.S. national average. In addition, much of Hawaiiĺs agricultural land was left fallow after the end of the sugar era and are now over-run with wildfire-prone invasive species. On the positive side, diverting and re-using waste to displace imports and virgin materials are very popular and frequently requested by community members in municipal and state proceedings. I include proving the concept of manufacturing organic and potash fertilizer capable of displacing imported fossil-fuel derived fertilizers, from locally generated organic wastes. We obtained over 800lbs of invasive species wood chips and grasses from a wildfire prevention project, prepared it for gasification, gasified it to make industrial hydrogen and ash in a fluidized bed pilot plant, blended the ash with other organic wastes generated within Hawaii into two fertilizer types, and tested the fertilizers in two tropical food crop trials at two agricultural research stations. The performance of both fertilizer types was comparable to common imported organic and synthetic fertilizer products, at a lower modeled cost to produce compared to imports. Collection and preparation for gasification of mixed tropical at 100 times larger scale than in Phase I Physical gasification trial on real-world tropical greenwaste in commercial gasification conditions Fertilizer formulation with real-world locally wastes at 100 times larger scale than in Phase I On-farm crop trials on commercial organic and conventional farms in Honolulu and Hilo, Hawaii System Engineering for a commercial plant including vendor quotes and system integration Technoeconomic optimization for product quality, commercial viability, and community benefit Workforce development and community benefits opportunity identification