Preparing, Characterizing, and Evaluating Ammoniated Lignin Diesel from Papermaking Black Liquor

Managing papermaking black liquor has always been a problem in the papermaking industry. Alkali lignin is biologically difficult to treat and is the main factor that affects the treatment of papermaking black liquor. In this study, we used ammonization to process lignin from papermaking black liquor into ammoniated lignin and then added the ammoniated lignin into diesel oil by applying microemulsion technology. We investigated the influences of several process parameters on the diesel separation rate using an orthogonal array design. The ranges of hydrophilic-lipophilic balance (HLB), emulsifier, and co-emulsifier were from 8.3 to 9.3%, from 4 to 6%, and from 0.8 to 1.6%, respectively. When range analysis and analysis of variation (ANOVA) were conducted, the order of affecting ammoniated lignin diesel production was determined as follows: HLB > emulsifier > co-emulsifier. Meanwhile, optimum microemulsion process conditions were found as follows: HLB (9.3%), emulsifier (6%), and co-emulsifier (1.6%). The physicochemical characterizations of ammoniated lignin diesel were determined to evaluate its feasibility as an engine oil. Engine capacity load velocity characteristic trial was conducted, and the engine emission of ammoniated lignin diesel was determined. Results show that ammoniated lignin diesel can save pure diesel by nearly 10% compared to traditional diesel; consequently, ammoniated lignin diesel can be used directly as a suitable fuel.