Graphical revamping of a delayed coker unit: A case study from an Egyptian refinery

Delayed coker units are used to upgrade the heavy feedstocks (barrel bottom) to valued low-carbon liquid fuels (light fractions) and coke, but they are considered one of the most energy-intensive processes in refining industries. It is highly recommended to optimize the energy efficiency of such units to reduce CO2 atmospheric release to mitigate green-house-gas (GHG) implications. The objective of this research is to maximize the energy efficiency of delayed coker units and reduce electricity consumption in particular and CO2 emissions accordingly. In this case study, a Pinch Technology-based method is developed to redesign a network of a delayed coker located in some modern refineries in Egypt to improve its energy efficiency, enhance profit and reduce carbon emissions. The new revamping method relies on implementing graphics and integrating Pinch insights. The case study contains twenty-nine exchanger units, including about thirty-six process streams. The coker unit under study is relatively new, and processes vacuum residue into LPG, naphtha, light and heavy gas oil, and coke. The outcome of this case study resulted in savings of 4.72 MW of hot energy and 4.83 MW equivalent of electricity savings, and reduced energy costs of 3,390,388 US $ per year with total capital investment of 321,819 US $. The corresponding annual cut in CO2 emissions is 32,184 t, leading to better environment with respect to climate change. The relative energy savings and carbon emissions cut are 11 % and 13 %, respectively compared with the current operation.