Flowsheet Simulation And Heat Exchanger Networks Optimization Of Atmospheric And Vacuum Units

The shortage of petroleum energy has been an important factor restricting the economic development of China.In 2017,China's oil consumption reached 58.8 billion tons.However,during the petrochemical industry production process,energy consumption and material consumption are huge.The energy consumption of atmospheric and vacuum unit,as the first process of crude oil processing,reaches 25%~30%of that of the whole refinery.Therefore,it is very meaningful to calibrate and save energy and reduce the cost of operation.The research subject of this paper is an atmospheric and vacuum units in the first workshop whose energy consumption reaches 11.98 Eo/t.The process was calibrated by the chemical process software aspen plus,and the heat transfer network was diagnosed on the basis of the calibration.The problem was found and the optimization scheme was put forward.In the simulation process,the components are defined according to the crude oil assay data,and then select the suitable physical property method PENG-ROB equation and the convergence module design-spec.in the basic module,the distillation column uses the PetroFrac,and the heat exchanger uses the HeatX.According to the result of process simulation,the heat transfer process of initial bottom oil and the heat transfer process of reducing bottom oil are analyzed,and the heat transfer network is simulated by Aspen Energy Analyzer.Compared at 15?to 25?,the pinch temperature and utility consumption under the heat transfer temperature difference are determined.Finally,15?is selected to determine the grid diagram of heat transfer network.Then the unreasonable position of heat transfer is analyzed according to the pinch theory,and the feasibility of the transformation scheme is explored.After optimization,the heat transfer area increased by 257.2m~2 of E122,the E125 is231.5m~2,and the E128 is 112.3m~2.and the heat transfer area of new heat exchanger E125N was increased 523m~2.The utility consumption is reduced by 2105 MJ/h;the other is to study the feasibility of changing the deep well water into circulating water of the top reducing oil and gas cooler,mainly to calculate and analyze a heat exchanger in the cooler E146 of the decompression tower.When the circulating water quantity of each heat exchanger is in112.5t/h,the required heat transfer area is 198 m~2,and the actual heat transfer area of the heat exchanger is 215 m~2.After calculating the effect of circulating water on heat transfer,the feasibility of the revamping is determined.