Optimizing atmospheric distillation unit for maximum light petroleum gas yield and comparative case studies

Interest in productivity improvement of quality fuels from petroleum refinery has been on the rise due to high market demand for these fuels as a result of increasing public concern on health, environment and stricter emission regulations. In Indonesia, the use of high quality fuel such as light petroleum gas (LPG) was promoted to prevent the high mortality rate and morbidity among Indonesian households due to household air pollutants (HAP) that are emitted by kerosene during cooking. There are a variety of options to improve production of the light end cut from which the high quality fuel such as light petroleum gas (LPG) is derived. The first would be by feeding proper selection of crude oil or pre-treated crude into the atmospheric distillation unit (ADU). Second would be by utilizing a new column configuration or design that would allow for the increase in the light end cut. In this presentation, optimizing the LPG yield based on the controllable factors and limitations in the present refinery installation was proposed. The dynamic refinery process of the basic refinery layout was modeled using Aspen Plus. Response surface methodology (RSM) from Design Expert was then employed to optimize the atmospheric distillation operating parameters in order to achieve the maximum LPG yield. Results from this study indicate that the LPG yield was improved from 2.30wt% to 5.17wt% by optimization of the parameters at the refinery conditions of 603K furnace temperature, 33 stages and 1.8% steam to feed ratio. Among the three operating parameters selected in the study, the number of stages was found to be the most significant factor that affected the LPG yield.