ENERGY OPTIMIZATION OF A HYDROTREATING PROCESS FOR GREEN DIESEL PRODUCTION FROM PALM OIL

Abstract

This work focus on the hydrotreating process for green diesel production from palm oil and the energy optimization of the process. The process simulations were performed by using Aspen plus program. The green diesel production process from palm oil by using NiMoS2/γ-Al2O3 is considered. The results show that the green diesel yield, green diesel purity, liquid product distribution, hydrodeoxygenation (HDO) and decarbonylation (DCO)/decarboxylation (DCO2) reactions occurring in the process are good agreement with the experimental data. The tolerance allowed is not more than 2%. In addition, the energy optimization for green diesel production process by using the heat exchanger network is studied. To minimize the energy consumption of the process, the energy optimization is divided into 3 strategies. From the energy optimization strategy 1 and 2, the energy consumption of 81.79% and 80.73% are decreased, respectively. The difference of energy saving of strategy 1 and 2 is 1.07%. Thus, the exchanged heat sequence affects on the energy saving due to the boundary of minimum temperature difference of exchanged hot and cold streams. Based on the energy optimization strategy 3, split hot stream, the energy consumption of 89.36% is decreased when compared with the original process. The results suggest that the energy optimization strategy 3 is very promising process for green diesel production. When comparing the cost of heat exchanger network construction and cost of utilities, the energy optimization strategy 3 has the lowest annual cost. Therefore, the energy optimization strategy 3 is the most worthwhile investment. In case of the pressure drop over the process, the compressor is used to increase the pressure that results in the increasing energy requirement.