Parametric analysis of total costs and energy efficiency of 2G enzymatic ethanol production

A quasi-linear section of the TCP surface was identified delimited by (300-1100 ton DB/day) and (80-55% pc) with increments no larger than 21% of the minimum TPC obtained (0.99 USD/l etOH for 2100 ton DB/day and 80% pc). Major cost contributions are detailed and quantified for boundary cases of this surface. Energy consumption and production were also calculated for all the plant capacity and feedstock pc cases, taking into consideration the Maximum Energy Recovery (MER) obtained from a Pinch analysis. The end-use energy index eer was less than 0.82 for all cases, thus stressing the need to use process equipment with lower energy requirements. TPC are compared against previously published results for SHF technology between 500 and 2100 ton DB/day plant capacities. These values were updated and normalized with respect to feedstock and enzyme costs employed in this work. Differences among TPC and recently published normalized results are within a ±5% range, thus confirming the dependence of TPC from feedstock and enzyme prices, regardless of flowsheet technology and economic conditions.