Economic comparison of a continuous ABE fermentation with and without the integration of an in situ vacuum separation unit

Abstract

The development of renewable fuels has achieved enormous progress motivated by the rapid decline in petroleum resources and their oscillating price. After a wave of interest in bioethanol and biodiesel, biobutanol has been intensely investigated over the last decade and is considered a suitable renewable fuel. Biobutanol is most often produced through the Acetone-Butanol-Ethanol (ABE) bacterial fermentation process. This process is plagued, however, with high recovery costs because of the low final butanol concentration ($0.01 g/g, 1 wt %) due to product inhibition on the microorganisms. To partly alleviate this problem and increase productivity, in situ butanol recovery techniques from the fermentation broth were proposed. These integrated methods increase the final concentration of butanol, and as a result improve the separation efficiency of the process. This paper compares the economic feasibility of a large-scale continuous ABE fermentation process with and without integrating a vacuum separation unit. It is illustrated that based on the current market price of butanol, only the integrated fermentation process is economically feasible for discount rates up to $45 %. Adding an in situ butanol recovery technique made this process profitable compared to the conventional fermentation process analyzed under two different scenarios: constant fermenter volume and constant butanol production rate. The net present values (NPV) of the conventional process were found to be negative for both scenarios, whereas the integrated vacuum process had a NPV of US$ 87 000 000 at the end of 10 years of operation based on a discount rate of 10 %.

A Feasibility Study of Cellulosic Isobutanol Production—Process Simulation and Economic Analysis

“…The main modeling and economic assumptions made in the analysis are presented in Table 5. Those values were selected based on previous relevant publications [8,31,[36][37][38] as well as on the authors' engineering judgement. In the case of SCA, the initial concentration of sugars in the fermentor is limited to 60 g/L and the conversion of sugars was assumed to be 85% (assuming equal conversion of pentoses and hexoses) with the remaining percentage converted to biomass cells.…”

“…This kind of uncertainty is usually not considered at all or is, at best, partially addressed by single-point sensitivity analysis where specific key parameters are varied independently. [38] This work presents a techno-economic analysis of two alternative process scenarios for a small-scale biorefinery that produces isobutanol from corn stover. The uncertainty in the estimation of the unit production cost associated with the choice of certain key parameters (e.g., sugars conversion, corn stover cost, enzyme price and loading ratio) is addressed by a Monte Carlo simulation.…”

Techno-Economic Analysis (TEA) of Different Pretreatment and Product Separation Technologies for Cellulosic Butanol Production from Oil Palm Frond

“…The potential of large-scale cellulosic butanol production is limited by the low efficiency of the pretreatment process as well as the extensive downstream processing requirement. Studies have revealed both operations as potentially driving the production cost of cellulosic butanol [1][2][3][4]. Pretreatment is essential to reduce the recalcitrant structure of lignocellulosic materials and therefore results in better sugar yield after the enzyme hydrolysis process [5].…”

“…Several available works compared the energy performance of the product separation process [1,4,8,10,13]. However, researchers have agreed that direct comparison among the available literature is hard due to the various operating conditions and system assumptions used [18].…”

Economic optimization of in situ extraction of inhibitors in acetone-ethanol-butanol (ABE) fermentation from lignocellulose

“…At the best of our knowledge, a scheme of production of ABE, butyric acid (BA), furans and phenolic compounds by liquid-liquid extraction has been not studied in the literature. Process modeling is an important tool to determinate the viability of new processes [25][26][27][28]. For these reasons, in this work, a detoxification system with simultaneous saccharification, fermentation, and extraction (SSF-E) ( Fig.…”