Thermodynamic analysis of crude oil distillation systems

Abstract

SUMMARYThis work deals with a thermodynamic analysis of crude oil distillation systems to study energy and exergy efficiencies for system analysis, performance evaluation and optimization. In this regard, a new analysis methodology is proposed, and the SimSci/PRO II (2000) is employed as a simulation package for the required parametric studies, particularly to study the effects of the distillation column temperatures and pressures on the efficiencies. The simulations are carried for the operating conditions of the model. It is found that the total irreversibility losses are 608 MW for a flow rate of 507 kg s À1 [e.g. 56% by the Atmospheric Distillation Unit (ADU), 26% by the Vacuum Distillation Unit (VDU) and 18% by the heaters]. The highest irreversibility losses occur in the ADU as the main separation takes place there. Of the losses, 6.2% are due to chemical exergy losses associated with the separation process itself. The rest of the losses are due to the physical exergy losses mainly because of the temperature difference. The energy efficiencies are 0.497 for the ADU, 0.579 for the VDU and 0.519 for the overall system. The exergy efficiencies are 0.433 for the ADU, 0.501 for the VDU, 0.821 for Heater 1, 0.956 for Heater 2 and 0.233 for the overall system. The overall efficiency is not equal to the product of the components efficiencies.

Energy intensity and environmental impact metrics of the back-end separation of ethylene plant by thermodynamic analysis

“…In order to achieve this, the thermal analysis produces 'Column Grand Composite Curves' (CGCC) and 'Exergy Loss Profiles.' The user makes changes to column configurations and specifications until CGCCs and exergy profiles display closer actual and ideal operations [14,16]. The CGCCs are displayed as the stage-enthalpy (Stage-H) or temperatureenthalpy (T-H).…”

“…This approximation takes into account the inefficiencies introduced through column design and operation, such as mixing, pressure drops, multiple sideproducts, and side strippers. Using CGCC is significant because (1) it is a graphical tool to assess the current energy use and flow conditions of distillation operations, (2) it is based on the complex and rigorous stage-by-stage calculations, and (3) it can lead to the qualitative and quantitative guidance [4,13,15,16] in identifying the targets for potential column modifications for the following:…”

“…A part of accessible work potential is always lost in any real process. Exergy losses (destructions) represent inefficient use of available energy due to irreversibility and should be reduced by suitable modifications [12,16]. As the exergy loss increases, the net heat duty has to increase to enable the column to achieve its required separation task.…”

Advanced exergy analysis of distillation tower and simulation and optimization by hysys

“…Exergy analysis includes conservation of mass and energy balance together with the second law of thermodynamics. [2] Published a thermodynamic analysis of crude oil distillation systems, which includes aspects like energy and exergy analysis, performance evaluation and system optimization. [29] Have shown that large savings could be obtained because of reduction of high-quality energy.…”

Exergy Rate Profile of Multicomponent Distillation System

“…Hence going a step further, to evaluate the quality of energy lost via exergy analysis is an efficient technique for reducing inefficiencies. [2] published a thermodynamic analysis of crude oil distillation systems which includes aspects like energy and exergy analysis, performance evaluation and system optimization.…”