Reactor design for production of fermentable sugars from empty fruit bunch

Abstract

Bioethanol is a fuel produced from sugar fermentation process that used bio-based renewable sources as feedstock. As the second largest producer of oil palm, Malaysia has abundant of empty fruit bunch (EFB) waste. Despite of tremendous experimental studies done on effectiveness of using EFB for production of bioethanol, the process implementation in industry is still discouraging. This is due to lack of proven technology and high capital cost of investment. Hence, there is a need to find a straight-forward and cost effective process with a promising glucose yield. From previous experimental work, it has been proven that combination of low pressure steam heating (LPSH) and dilute acid pretreatment (DAP) able to gain a glucose yield of 78.6%, which is comparably higher than other pretreatment methods. In this present study, a block flow diagram was developed based on the data provided in the experimental work. The analysis then continued with mass balance calculation of process operation. With a scale up feedstock to ratio of 10 (to 100g of EFB), both pretreatment and hydrolysis process unit operations were modelled in Aspen Plus simulator for production of fermentable sugars. The reactors were based on RStoich and RYield reactor block due to unavailability of kinetic rate of reactions. Mass balance results from both experimental and simulation were compared and the difference was found to be around 0.73% to 0.85%. This indicated that the assumptions in simulation modelling were almost accurate to the actual experimental works. The reactor was sized based on the largest unit operations volume, which was determined to be 0.01791 m3. Detailed reactor’s mechanical design was illustrated using Microsoft Visio. Using bare module cost technique, the cost estimated to build this fermentable sugars reactor was around RM 111 000. This design work could be considered as a significant progress in the effort to bring the experimental works to industrial application.