Ethyl levulinate is a diesel additive that has received special attention recently due to its potential for production in large quantities from inexpensive feedstocks. Several processes have been developed for the conversion of biomass into levulinic acid and ethyl levulinate, and an economic analysis of these routes would indicate the main hindering factors of their commercialization. This Review focuses on filling this gap in current knowledge by gathering data from scientific papers and patents to create a simulation to analyze processes by focusing on the production of ethyl levulinate in nine countries or regions across the globe. The key indicator to analyze the economic feasibility of ethyl levulinate production is a comparison of its minimum selling price to the local wholesale price of diesel on an energy basis. Processes simulated in Brazil, China, and India presented promising results with feedstocks such as sugarcane bagasse and rice residues. Also, the integration of ethyl levulinate production into existing ethanol plants is a factor that may improve process economics. Overall, this Review specifies key factors in economic and environmental performances of the processes to indicate research topics that could achieve high impact on industrial‐scale processes once matured.

No abstract

Levulinic acid (LA) is currently one of the most promising chemicals derived from biomass. However, its large-scale production is hampered by the challenges in biomass hydrolysis and the poor selectivity due to the formation of humins (HUs). This study addresses these challenges using the biorefinery concept of biomass fractionation. A three-step process (pretreatment, delignification, and acid-catalyzed conversion) was optimized to produce LA from SCB considering the yield (Y LA ), efficiency (E LA ), and concentration of LA (C LA ) as functions of temperature, reaction time, acid concentration, and solids loading. By means of a multi-response optimization, values of Y LA (20.9 ± 1.25 g/100g ISF-D ), E LA (37.5 ± 2.24 mol%), and C LA (25.1 ± 1.50 g/L) were obtained at 180°C, 75 min, 7.0% w/v H 2 SO 4 , and 12.0% w/v of solids loading. Six scenarios for production of LA were analyzed in terms of yields of LA, HUs, lignin, and other sugar-derived products considering one-, two-, or three-step processes. The economic analysis indicated that the three-step scenario delivers better economic figures given that other valuable biomass fractions (hemicellulosic sugars and lignin) are better used and contribute to the overall economic performance of the process. The results also demonstrate the burden of HUs in the economics of the process because it was shown that the largest production of LA is also linked to the largest formation of HUs, which does not necessarily yield the best economic results. These findings indicate the importance of added value by-products for the profitable production of LA in biorefineries.

Lactic acid production is highly affected by the fermentation pH. The need for neutralizing agents and the salts produced during fermentation have a significant impact on the overall process performance. Changing the neutralizing agent and allowing lower pH fermentation can improve the process profitability. This work investigates the impact of fermentation parameters and evaluates the process economics of alternative downstream processing designs to produce lactic acid. The results show that low-pH fermentation (pH = 3.86) was profitable (internal rate of return, IRR > 10%) at a fermentation yield of 0.97 g/g sucrose. Decomposing the salt subproduct to reduce the environmental burden associated with gypsum disposal has a significant impact on the economic performance, resulting in a lower IRR than the other designs. Although the salt decomposition process has a high energy demand, it is compensated by the savings obtained in the downstream processing, thus resulting in a similar overall energy demand when compared to conventional reactive distillation. A novel process configuration with ammonium sulfate subproduct shows potential for 3 p.p. higher IRR and up to 30% lower fuel demand in comparison with the conventional process. Therefore, alternative downstream processes could drive low-pH fermentation to outperform the conventional process without any neutralizing agent.

No abstract