Investigation of Heat Recovery with Pump-Arounds at a Crude Oil Atmospheric Distillation Tower

Effect of application of pump-arounds in an atmospheric crude oil distillation column on tower parameters as well as on the heat balance of the whole unit was investigated. Model of three cases was prepared Base case without, while Case1 with one and Case2 with two pump-arounds. After establishing the models Energy Integration studies were done in every case. Results showed that by applying pump-arounds the required tower diameter considerably decreased from 5,180 mm to 4,570 mm or 4,270 mm depending on its number. Another advantageous effect of using pump-arounds was that the internal flow rate of the distillation column became more uniform. However, it should be noticed that the tray design of pump-around section required special consideration due to the high liquid loads. Results of Energy Integration studies to be done at tmin= 20 °C and with overall heat transfer coefficient of 0.3 kW/m 2 °C showed that both the external heating and cooling requirements significantly decreased (Qc: 23,256 kW → 14,207 kW / 13,569 kW; QH: 23,256 kW → 14,207 kW / 13,569 kW) meantime the attainable process/process heat exchange increased (33,475 kW → 45,238 kW / 45,434 kW). The temperature of cold stream (e.g. crude oil) leaving the pre-heat train also improved (147 °C → 180°C) by realizing the heat recovery at higher temperature levels. With implementing pump-arounds (Case1/Case2) the total process/process heat exchanger area, which calculated with using the Composite Curves, were higher than that was in Base case. Taking everything in account it can be stated implementation of pump-around system in the crude oil distillation tower had clear positive effect on both the capital and operating expenditures.