Optimising Process Conditions to Obtain Distillate Properties Within Regional Specifications

In this work, a case study of a modular crude oil refinery is carried out. Located in Imo State, Nigeria, it is the first refinery to simultaneously produce four (4) petroleum products - Naphtha, Kerosene, Automotive Gas Oil (AGO) (i.e., Diesel) and Heavy Pour Fuel Oil (HPFO), that have constantly met the requirements of the Nigerian Department of Petroleum Resources (DPR). The refinery is situated beside the Ibigwe Marginal Field from which it obtains its crude oil; it represents perhaps the personification of efficiency in maximizing value from petroleum resources. Numerous lessons exist for prospective modular refiners. The paper aims to identify optimal process conditions and discuss a data-focused strategy utilized in ensuring optimal distillation column parameters required to achieve the production of "on-spec" (that is, meeting the desired regulatory/client quality specifications) distillates. The set points of temperatures and pressures for the distillation and stripping of each product were examined, while assessing the impact of changes in feed stock properties, product specifications or ambient conditions and the adjustments that needed to be made to process conditions. Some examples of the concerned characteristics of the product required to meet specification are API Gravity, Flash point and Pour Point. The reflux temperature, petroleum products draw rate, etc. are few variables to be appropriately manipulated. Strategies were developed and implemented for all stages of the refinery’s development – preliminary ones being the Design stage and Construction stage, with the ongoing one being the operation stage. Literature alludes to refiners categorizing "meeting specifications" as a potential problem. For example, you have now obtained "on spec" kerosene, what quantity of "on spec" diesel is left? In this paper, the technical journey to meeting DPR requirements is narrated, aiming to transfer knowledge and further develop the nation’s ability to meet its energy needs.