Innovative biorefineries for cleaner waste textile management towards circular economy: Techno-economic analysis

Abstract

The primary practices for waste textile management are landfill and incineration, generating serious environmental problems while they have a high potential for sustainable production of different green products. This study dealt with the economic analysis of bioethanol production and polyester recovery from waste textile through different scenarios. The pretreatment plays a key role in the biofuel production from waste textile and the most promising methods are pretreatment with NaOH, NaOH/urea, NaOH/thiourea, NaOH/urea/thiourea, and N-Methylmorpholine N-oxide, evaluated through scenarios 1 to 5, respectively. After pretreatment, the cotton part is enzymatically hydrolyzed and fermented through simultaneous saccharification and fermentation. Detailed simulations of the processes were carried out by Aspen Plus, and economic studies were conducted by Aspen Process Economic Analyzer for each scenario. The bioethanol production price were 0.447, 0.524, 0.624, 0.618, and 1.244 $/L for scenarios 1 to 5. The total capital investments required for scenarios 1 to 5 were 38.54, 38.60, 38.42, 38.57, and 39.35 M$, respectively. The profitability index for scenarios 1 to 5 were 2.17, 1.92, 1.61, 1.34, and 1.51. Therefore, the biorefinery based on producing bioethanol from waste textile is economically feasible. Moreover, In scenario 1, the payout period was the minimum time of 3.56 year, and the net return rate was 117.16. Sensitivity analysis also reveals that the price of waste textile has a significant impact on the profitability of the designed biorefinery. Scenario 5 is the most sensitive to variations in waste textile price; a 100% increase in the cost of waste textile increases the cost of producing bioethanol to more than 1.45 $/L, respectively.