Exceeding Pinch limits by process configuration of an existing modern crude oil distillation unit – A case study from refining industry

Crude Distillation Unit (CDU) represents significant challenge for retrofitting and energy optimisation as the most energy intensive consumer in a conventional crude oil refinery. Pinch Technology and its based-methodologies are found primary keys for decades to energy savings in refining industries for a range of common economic-based and environmental objectives or applications. Typical benefits in energy savings are reported within 20–40% of original designs. However, such savings are limited and questioned when modern refiners are dealt with. The current paper addresses the revamping of a modern refinery exhibiting an existing high energy efficiency (≈93%). This implies the maximum potential energy savings would only be 7% at current process conditions. The present research proposes an algorithm that tackles energy recovery of modern refiners, enabling additional savings beyond the energy targets set by the existing process. The algorithm starts by process simulation and validation against real plant data, followed by a network optimisation, e.g. stream splitting, to reach the energy targets set by Pinch Analysis . The energy targets are then moved to another lower level by performing potential process modifications to reduce the energy consumption further. Results showed that the current modern refinery unit could reach its energy targets by stream splitting modifications with hot energy savings of 2.69 MW. Process modifications resulted in additional energy savings of 31.3% beyond the current level of the existing plant alongside less than a year of payback period for estimated capital investment. An environmental assessment is performed, and comparable reductions were obtained with respect to greenhouse gas, with reduction in CO 2 emissions by 45.1%. The proposed retrofit methodology is applicable to minimising energy consumptions of refiners including modern units to achieve energy levels beyond energy targets by new process modifications.