the study of decrease in co2 emission using pinch technology

Naphtha hydrotreating is a refining process that removes sulfur, nitrogen, and other impurities from naphtha. co2 emission pinch analysis (cepa) is a technique used for planning and optimizing energy systems to minimize co2 emissions. this study aims to optimize the heat exchanger network of a naphtha hydrotreating unit based on the pinch technology with three designed scenarios to reduce the co2 emission. in the scenario i the heat exchanger network (hen) is modified to achieve the optimum δtmin. using pinch technology. fuel switching between natural and fuel gas is applied in scenario ii for co2 emissions reduction. an economizer installation at the furnace stack is suggested in scenario iii to increase the thermal efficiency of the furnaces and reduce co2 emissions. ultimately, the integration of all three scenarios is effectively performed. scenario i reduces the energy consumption of hot utilities and co2 emissions by 40.4% and 41.3%, respectively. the total annual cost of the unit is minimized in scenario i at the optimum ∆tmin.=12 °c. scenario ii reduces the fuel consumption from 100 kg/h and the co2 emission by 16%. while scenario iii decreases co2 emission by 5.5%, the new integration method of scenarios i–iii provides the minimum emission reduction by 52.3%. the use of natural gas instead of fuel gas, and energy recovery from flue gas to preheat the incoming streams to the furnace in scenarios ii and iii are found to be the reasons for the efficient co2 emission reduction of the hydrotreating unit.