Investigation of combustion and spray of biowaste based fuel and diesel blends

An alternative source of biofuels is through the use of biowaste, as an estimated 20 million dry tons of volatile organic compounds is deposited in U.S. municipal wastewaters every year. Most of the energy content is not recovered, though biowaste is theoretically a colossal source of renewable energy. Biocrude diesel can be converted from wet biowaste via a process called hydrothermal liquefaction (HTL), which can be created from various feedstocks such as algae, swine manure, and food processing waste. Previous experiments were conducted in a single-cylinder diesel engine used a diesel blend consisting of 10% and 20% HTL fuel. Preliminary results showed that the HTL blends had roughly similar power and emissions in comparison to pure diesel. In order to fully understand what the spray and combustion is like, it is necessary to study these mixtures in a constant volume chamber. The experiments were conducted at different temperatures and atmospheric conditions, revealing that the HTL blends has similar combustion and soot characteristics when compared to diesel. The HTL blends has roughly the same amount of apparent heat release rate and combustion pressure as diesel and performs better under low oxygen concentrations. The HTL fuel blends resulted in a shorter spray penetration length of HTL fuel than pure diesel, though showed more soot emissions.