Technoeconomic Analysis of Multiple-Stream Ethanol and Lignin Production from Lignocellulosic Biomass: Insights into the Chemical Selection and Process Integration

Abstract

Technoeconomic analysis of multiple-stream lignin and ethanol production from 100 Mt/h of industrial hemp biomass is conducted based on three scenarios: I, H2SO4 pretreatment and NaOH neutralization; II, parallel HOAc and NaOH pretreatments, solid separation, and liquid integration; and III, parallel H2SO4 and NaOH pretreatments, solid separation, and liquid integration. The technical and economic advantages and disadvantages of the three processing scenarios with different production technologies are discussed. A discounted cash flow rate of return assessment is executed to ascertain the ethanol minimum selling price (MSP). The chemical reagent used for pretreatment is found to have a significant impact on economic aspects with an annual operating cost of $628.34 million for scenario II, which is strikingly higher than $367.97 million for scenario I and $347.86 million for scenario III. The advantage of the largest lignin and ethanol output with a total revenue of $190.53 million annually for scenario II is offset by its high total capital investment and operating cost. Scenario III reaches the lowest ethanol MSP of $6.16/gal compared to $9.04/gal from scenario I and $10.26/gal from scenario II, indicating that parallel H2SO4 and NaOH pretreatments with subsequent integration are more efficient than a single H2SO4 pretreatment. Sensitivity analyses identify biomass and reagent costs and glucose-to-ethanol yield as the dominant contributors to the ethanol MSP. Although the present biorefineries are not profitable yet, this study might provide new perspectives for biomass valorization in terms of chemical selection and engineering design.