An integrated simulation–optimisation approach for free fatty acid removal in palm oil deodorisation process

Abstract

Deodorisation is the key process to produce high‐quality refined, bleached and deodorised palm oil (RBDPO) in a palm oil refinery. In this work, an integrated simulation–optimisation approach was adopted for the analysis of a deodorisation process in an operating palm oil refinery. The process includes a deodoriser unit that removes free fatty acids (FFA) from bleached palm oil (BPO), and a vacuum scrubber utilising palm fatty acid distillate (PFAD) to reduce the FFA content entering the vacuum system. Being a proprietary technology, deodoriser is not found in the standard models of commercial simulation software. Approximation was made in simulation, with results compared to plant data. Detailed analyses showed that the reduction of FFA content relies on deodorisation temperature and pressure, stripping steam flowrate, as well as the temperature and flowrate of PFAD entering the vacuum scrubber. An optimisation model was solved to maximise profit from the deodorisation. Results showed that the FFA content entering the vacuum system is reduced significantly by 49.7%, leading to higher recovery of FFA in PFAD and lower loss into the condenser section. Applying the optimum values to the refinery has resulted in FFA levels greater than 91.2% in PFAD and RBDPO yield improvement of 0.5%.

Process Simulation of Steam Stripping of Bleached Palm Oil Deodorization for Removing Free Fatty Acids using DWSIM

“…Nevertheless, this simulation demonstrates that the deodorization process was fairly well described by process simulation, modelled using absorber column unit operation. Similar results were also obtained by the simulation work conducted by [12] using Aspen HYSYS software. Nevertheless, this current simulation results could serve as the upper bound marginal error for the RBDPO composition of FFAs and water when conducting deodorization of BPO using simulation software (absorber column).…”

“…The comparison of the current simulation results was also done against a real plant data and was presented in Table 4. The real plant data of RBDPO compositions were taken from the literature as reported by [12]. Despite of the difference in magnitude between the plant data and simulation for FFAs and water content in the "RBDPO" stream, nevertheless, this current simulation can be used to represent the deodorization process of BPO with high accuracy of TGs components mass percent.…”

“…Higher temperature beyond 260 °C will accelerate the formation of more FFAs resulting from the thermolytic or hydrolysis reaction. Due to complex chemical phenomenon of hydrolysis to form FFAs, most of the modellng and simulation works on physical refining of vegetables oils does not integrate the hydrolysis reaction in the simulation works [9][10][11][12].…”