(105d) Atmospheric/Vacuum Crude Distillation Integration for Energy and CO2 Emission Reduction

Oil refineries are continuously pushing towards reducing its energy consumption and CO2 emissions. In grassroots design of oil refineries pre-heat trains are a major design degree of freedom to minimize load on crude heater and consequently reducing the energy-based CO2 emission. Integrating the vacuum unit with the atmospheric unit can further reduce both energy consumption on the crude heater and the CO2 emission. The grassroots design approach of engineering contractors normally puts the emphasis on the minimization of the HEN area and the number of units, using shell and tube heat exchanger; ahead of energy savings and CO2 emission. This approach is myopic since it ignores for instance integration between units and using other types of heat exchangers that can allow higher cross over temperatures between the hot and cold streams; resists fouling and renders better heat recovery without extra tangible capital cost.

In this paper the integration between typical crude atmospheric/vacuum units is introduced. The objective of having minimum number of units is traded off against desired levels of reduction in both crude atmospheric &vacuum heaters thermal load and CO2 emission. Several schemes for heat exchangers network with different levels of sophistication are proposed. The results of an industrial case study exhibit the role of pre-heat HEN good design in maximizing energy savings and CO2 emission reduction while keeping number of units target at minimum. The beforehand design target of having a ?maximum of two splits in the crude stream in the preheat train is preserved? and the paper shows that even under such very limited degree of freedom in design there is an excellent room for improvement in the energy consumption and CO2 emissions reduction.