Chemical exergies of the elements

Szargut, Jan

doi:10.1016/0306-2619(89)90016-0

Cited by 243 publications

(110 citation statements)

References 6 publications

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“…Chemical exergy accounts for deviations in chemical composition from reference substances present in the environment. In this work, chemical exergy is calculated using the reference environment defined in Szargut [12,52,53]. The specific chemical exergy of a given mixture e ch mix is expressed as [54]:…”

Section: Flow Exergymentioning

confidence: 99%

On the definition of exergy efficiencies for petroleum systems: Application to offshore oil and gas processing

Nguyen

Voldsund

Elmegaard

et al. 2014

Energy

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Section: Flow Exergymentioning

confidence: 99%

On the definition of exergy efficiencies for petroleum systems: Application to offshore oil and gas processing

Nguyen

Voldsund

Elmegaard

et al. 2014

Energy

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“…The exergy efficiency of the discharging process can be evaluated using Equation (15). During discharging, air is heated from 25 o C to 65 o C. The exergy recovered in this process can be evaluated as…”

Section: Dischargingmentioning

confidence: 99%

Energy and Exergy Analyses of an Open Thermochemical Energy Storage System: Methodology and Illustrative Application

Abedin¹

2012

TOREJ

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Thermal energy storage (TES) is a developed technology for storing thermal energy that can diminish environmental impacts and provide more efficient and environmentally friendly energy systems. Among various types of TES systems, thermochemical TES is an advanced method with the potential for higher energy storage densities and more compact systems. The evaluation of such systems is improved significantly when exergy analysis is used to complement energy analysis. Here, a general open thermochemical TES is investigated using energy and exergy analyses. An example using experimental data is presented to illustrate the analyses. Efficiencies are determined for the overall TES cycle and its charging, storing and discharging processes. The overall energy and exergy efficiencies for system considered in the illustrative example are determined to be 69% and 23%, respectively. This result indicates that the efficiency of the thermochemical TES based on exergy is much lower than that based on energy, and that there is a significant margin for loss reduction and efficiency improvement.

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“…The chemical exergy of real chemical compounds is calculated based on the concept of standard chemical exergy, using the reference environment defined by Szargut [48,55,56]. The chemical exergy of hypothetical components e ch hyp is computed with the heuristic correlations of Rivero [57].…”

Section: Exergetic Accountingmentioning

confidence: 99%

“…This heat exchange faces two issues. First, all the gas streams should be cooled down to • C, and the oil stream has an initial temperature of [45][46][47][48][49][50][51][52][53][54][55] • C. The gas streams should therefore be cooled in two steps, by first exchanging heat with the oil, and then with cooling water. Secondly, the oil stream cannot be heated by only one gas stream, as the heating demand for the oil can reach up to 12 MW, while the cooling demand for each individual gas stream does not exceed 4 MW.…”

Section: Analysis Of the Site Profilesmentioning

confidence: 99%

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

Nguyen

Fülöp

Breuhaus

et al. 2014

Energy

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Oil and gas platforms are energy-intensive systems, which operate under changing boundary conditions over time. In this paper, the life performance of an offshore platform is analysed by comparing three representative stages of an oil field (early-life, plateau and end-life productions). The energy requirements are assessed by a process integration study, and the system inefficiencies are pinpointed by performing an exergy accounting. The heating and cooling requirements vary significantly over time, and most inefficiencies take place in processes where chemical exergy is consumed ( 50-55 %), thermal exergy is transferred ( 15-20 %), or mechanical exergy is varied ( 10-15 %). These findings are valid for all production periods: this suggests that more attention should be paid on a proper integration of the processing and utility plants, by, for instance, recovering heat from the turbine exhausts and from the exported gas. Multi-objective optimisations are conducted for evaluating the integration of steam and organic Rankine cycles, considering thermodynamic, economic and environmental performance indicators. They indicate that the profitability of a given improvement measure mainly depends on (i) the field properties, (ii) the platform operating strategy, and (iii) the production stage of the oil field. The implementation of steam networks appears promising, as it results in a better performance of the offshore platform and in larger economic profits.

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Chemical exergies of the elements

Cited by 243 publications

References 6 publications

On the definition of exergy efficiencies for petroleum systems: Application to offshore oil and gas processing

On the definition of exergy efficiencies for petroleum systems: Application to offshore oil and gas processing

Energy and Exergy Analyses of an Open Thermochemical Energy Storage System: Methodology and Illustrative Application

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

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