Techno-economic assessment on pilot-scale plant for fuel ethanol production from sweet sorghum stem by solid state fermentation

The technological process of pilot-scale plant for fuel ethanol production from sweet sorghum stem by solid state fermentation, which was set up in Weihai city, Shandong province of China, was described and techno-economic assessment of the plant was conducted with cost and profit analysis. Results showed that the ethanol conversion efficiency relative to theoretical yield was up to 95.8%. The residual vinasse was re-fermented and protein feed with 8% crude protein was obtained. The cost and benefit analysis showed that costs of absolute ethyl alcohol production and protein feed production were 5?033.8 yuan/t and 101yuan/t, respectively. Cash flow analysis showed that Net Present Value, Internal Return Rate and Profit/Cost of financial analysis in project level were 2?817.5 thousands yuan, 16.05% and 0.953, respectively when the social discount rate was 10%. And the dynamic pay-back period was 9-10 years. As a result, the project has a certain ability of making a profit. The sensitivity analysis showed that the sensitivity of IRR to changes of product price and operating cost was the highest and the sensitivity of IRR to initial investment was the lowest. The market risk of this project depends mainly on the product price at the current scale and technological conditions.