This study explores dual fueling a diesel genset with producer gas made from biosolids , wastepaper and woodchips generated at or brought into the Minoa (a village in New York) Wastewater Treatment Plant (MWTP) and the possibility of a dual fueled genset and gasifier reducing the MWTP operating costs. The producer gas resulted from gasifying the biomass in a downdraft Imbert style gasifier. Gasification of woodchips was first studied in the gasifier using two different sizes and types of woodchips. It was found that the denser hardwood chips 2 cm x 2 cm x 0.6 cm gave better performance than less dense willow chips 1 cm x 1 cm x 0.15 cm. The smaller, less dense chips restricted air flow and reduced temperatures in the gasifier oxidation and reduction zones. Particle size distribution from samples taken vertically through the gasifier also indicated restriction of air and fuel flow through these zones with the smaller, lighter chips. Dual fueling of the genset with the larger, denser woodchips reduced diesel consumption by approximately 75%.
Wastepaper, primarily newspaper, was then studied as gasifier fuel. It was first pulped, then the wet pulp was formed into 60 cm3 chunks, then dried and gasified. The wastepaper fuel was generally difficult to gasify because of its low density and tendency to hang up in the gasifier. Dual fueling the genset with producer gas from wastepaper only reduced diesel consumption by approximately 30%. Since wastepaper can be recycled by Minoa at no cost, gasifying its wastepaper was not recommended. Biosolids were then studied as gasifier fuel. Copious ashes were removed from the gasifier oxidation and reduction zones. Dual fueling the gasifier with producer gas from biosolids reduced diesel consumption by 70% - 90%.
Biosolids first processed through a filter press then pressed into roughly 15 cm3 chunks and dried gasified easily as long as the grate was continuously agitated. By generating electricity and the potentially valuable soil amendment biochar dual fueling a diesel powered genset with producer gas generated from biomass could save Minoa more than $14580 annually
