(569v) Failure Analysis of a Second Generation Biorefinery from OIL PALM Empty Fruit Bunches Using Graph Theory

The oleochemical sector in Colombia has been growing during the last decade as effect of the development of the biodiesel industry and the increase on demand of petrochemical substitutes and specialty fats (Rincón, Hernández et al. 2014). Currently, the oil palm is the most important oleochemical feedstock by yield, harvested area and production in the country. This crop reached a cultivated area of 477,000 hectares in Colombia in 2013, while the production of crude palm oil exceeded the one million tonnes for the same year. The palm oil extraction leads to obtain different by-products and residues with economical potential. Among these, the empty fruit bunches (EFB) are the solid residue that is produced in the highest amount from the fresh fruit bunches (FFB) of the oil palm (Quintero, Moncada et al. 2013; Rincón, Moncada et al. 2014). Usually the EFB represent 12 to 26% of the FFB in dry basis. This means that approximately 438 tonne of EFB are produced per km². Due to its high moisture content, this residue is not appropriate as fuel and currently it does not have any industrial application (Piarpuzán, Quintero et al. 2011). In this work, experimental and simulation procedures were performed in order to propose a biorefinery scheme to take full advantage of this waste.

The raw material was obtained from a palm oil extraction plant (Palmar Santa Elena) located in the southwest cost of Colombia. The EFB were characterized by measuring moisture content (AOAC 928.09 method), klason lignin content (TAPPI 222 om-83 method), acid-soluble lignin content (TAPPI 250UM-85 method) holocellulose content (ASTM Standard D1104 method), cellulose content (TAPPI 203 os-74 method), and ash content (TAPPI Standard T211 om-93 method).  Besides, the pretreatment of the EFB was also carried out experimentally. First, the raw material was conditioning, and then submitted to a two steps hydrolysis process consisting in an acid hydrolysis followed by an enzymatic hydrolysis. All the experiments were carried out in the Biotechnology and Agrobusiness Institute at the Universidad Nacional de Colombia at Manizales.

Based on the characterization results, an integrated biorefinery to obtain xylitol, ethanol, furfural, poly-3-hydroxybutyrate (PHB) and energy was assessed from the techno-economical point of view using simulation tools. The main simulation tools used were the commercial package Aspen Plus v8.0 and Aspen Economic Analyzer V8.0 (both from Aspen Technology, Inc., USA). Specialized package for performing mathematical calculations especially for kinetic analysis such as Matlab was also used.

In order to complement the simulation and quantitative analysis of the proposed process flowsheet, a qualitative analysis is performed in order to assess security issues. With the aid of graph theory most sensitive units to cascade failures are identified. In a system of interconnected units, a cascade failure can be defined as failure event that triggers the failure of successive units. The spreading dynamics of this failure across the process flowsheet cannot be simulated using process software. Therefore, a graph that represents the material and energy interactions between the process units is extracted from the process flowsheet, allowing the calculation of graph topological properties such as the centralities, which allowed identifying the most endangered units in the case of random cascade failures.

Piarpuzán, D., J. A. Quintero, et al. (2011). "Empty fruit bunches from oil palm as a potential raw material for fuel ethanol production." Biomass and Bioenergy 35(3): 1130-1137.

Quintero, J. A., J. Moncada, et al. (2013). "Techno-economic analysis of bioethanol production from lignocellulosic residues in Colombia: A process simulation approach." Bioresource Technology 139(0): 300-307.

Rincón, L. E., V. Hernández, et al. (2014). "Analysis of technological schemes for the efficient production of added-value products from Colombian oleochemical feedstocks." Process Biochemistry 49(3): 474-489.

Rincón, L. E., J. Moncada, et al. (2014). "Analysis of potential technological schemes for the development of oil palm industry in Colombia: A biorefinery point of view." Industrial Crops and Products 52(0): 457-465.