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Thermo-economics analysis was used to identify the most economic distillation hybrid configuration to dehydrate bioethanol mash (12 wt%) to fuel grade (99.5 wt%) based on economic objective of minimization of operating cost in this work. Three different hybrids of THIDC with azeotropic and, extractive distillation units were assessed using similar feed and product specifications of 1200 kmol/h (12 wt% ethanol) and 55 kmol/h (99.5 wt% ethanol) respectively . The six hybrid configurations were simulated using Aspen Plus ®. The hybrid of THIDC with conventional extractive distillation (THEX1) was shown to have the lowest irreversibility rate (lost work) and highest exergetic efficiency followed by the hybrid containing thermally extractive sequence (THEX3). The latter also has the lowest energy consumption. However, economic evaluation showed that thermally coupled extractive distillation hybrid (with THIDC) is the most attractive hybrid configuration dehydrating bioethanol to fuel grade at commercial scale with the highest return on investment (ROI) and the least annual product cost. This indicates its economic attractiveness when compared with the other hybrids considered in this work. The trade-off existing between economic and exergy efficiency favors the selection of THEX3 as the preferred choice for bioethanol refining among all the six hybrids investigated.

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Some oil and gas reservoirs are often weakly consolidated making them liable to sand intrusion. During upstream petroleum production operations, crude oil and sand eroded from formation zones are often transported as a mixture through horizontal pipes up to the well heads and between well heads and flow stations. The sand transported through the pipes poses serious problems ranging from blockage, corrosion, abrasion, and reduction in pipe efficiency to loss of pipe integrity. A mathematical description of the transport process of crude oil and sand in a horizontal pipe is presented in this paper. The model used to obtain the mathematical description is the modified form of Doan et al. (1996 and 2000) models. Based on the necessity to introduce a sand deposit concentration term in the mass conservation equation, an additional equation for solid phase was derived. Difference formulae were generated having applied Fick’s equation for diffusion to the mass conservation equations since diffusion is one of the transport mechanisms. Mass and volume flow rates of oil were estimated. The new model, when tested with field data, gave 85% accuracy at the pipe inlet and 97% accuracy at the exit of the pipe.

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in Wiley Online Library (wileyonlinelibrary.com).Ideal heat pump performance models containing one adjustable parameter and intensive thermodynamic variables were developed by transformation of the energetic functions of Rankine heat pump. Two unknown groups in the formulated model, labeled AKR and AKF, were found to curve fit to two intensive variables as linear functions. The parameters of the linear fits were obtained using the least square method; consequently, AKR and AKF were expressed as temperature-lift variables. Maximum errors of about 5% were encountered at conditions below reduced temperature of 0.8. Better accuracy was obtained in the range of practical temperature lift (i.e., 10-80 C). Only one fit parameter value is required by these models where similar correlations require three or more. Furthermore, unlike some of the available models where different equations are required for each working fluid, these equations are not working fluid specific and do not require thermodynamic properties' tables or charts.

The energy and exergy analysis of FCCU of Kaduna Refining and Petrochemical Company (KRPC) Nigeria is presented. The primary objectives of this work were to analyze the system components separately and to identify and quantify the sites having largest energy and exergy losses. The performance of the plant was estimated by a component wise simulation using Aspen Hysys software and a detailed break-up of energy and exergy losses for the considered plant has been presented. The ideal work was calculated to be (-74.169 MW) which characterized the system as work producing. Energy losses mainly occurred in the fractionator column where 46.6MW is lost to the environment while only 3.69, 1.77 and 0.68 MW was lost from the condensers, other equipment and absorbers respectively. The percentage exergy and second law efficiencies of the system was found to be 61.20 and 24.77 %.