Anomalous Properties of Some Fluids − with High Relevance in Energy Engineering − in Their Pseudo-critical (Widom) Region

Imre, Attila R.; Groniewsky, Axel; Györke, Gábor; Katona, Adrienn; Velmovszki, Dávid

doi:10.3311/ppch.12905

Cited by 16 publications

(19 citation statements)

References 24 publications

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“…Figure 4 presents the Widom lines for SC Ar (real Ar rather than the van der Waals Ar) together with that for SC water and CO 2 , based on the correlations presented by Imre et al (2019) in their Table 3 and verified here with the values obtained from the NIST WebBook (2021). Note that in Fig.…”

Section: Thermophysical Properties Of Sc Argon and Anomalous Behaviorsupporting

confidence: 61%

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

2022

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Supercritical (SC) fluid, which was discovered exactly two hundred years ago, was initially thought to have only one state with no distinction between the liquid and vapor. It is now considered to have two distinct regions --"liquidlike" and "gas-like," with thermophysical properties exhibiting anomalous behavior near the critical point (CP). This work highlights that the anomalous behavior, as observed above CP in the Widom region, extends to pressures and temperatures much below the critical pressure P c and/or critical temperature T c . Indeed, the anomalous region starts within the subcritical liquid state and extends well into the SC region. Motivated by many applications, extensive research has been devoted to thermal transport by SC water and CO 2 . However, both of these fluids are reactive and corrosive, and require high pressures (P c = 217.8 and 72.8 atm, respectively); SC water also needs high temperature (T c = 373.95°C for water). This paper presents, for the first time, argon as an alternative SC fluid for thermal transport, whose P c is lower (47.994 atm) and it can work at low temperatures (T c = -122.46°C). Argon is easily-available, nonreactive, noncorrosive, and environmentally benign. A thermal transport analysis of fully developed flow of SC Ar through an isothermally heated duct and its comparison with SC CO 2 and water demonstrates that for similar rates of heat transfer, the increase in cost of using argon is small, in terms of flow work required, whereas the benefits are substantial with regard to complexity (due to P c being much lower), operational maintenance, and life of the thermal systems. It is also revealed that 2 to 3 orders-of-magnitude enhancement in gaseous state heat transfer is possible by moving from subcritical to high-supercritical pressures; the effect being more pronounced at lower SC temperatures, even at cryogenic temperatures in contrast to SC CO 2 (T c = 30.98°C) and water.

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Section: Thermophysical Properties Of Sc Argon and Anomalous Behaviorsupporting

confidence: 61%

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

2022

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“…The utilization of supercritical fluids as cushion gas is a potential strategy to tackle these issues. For supercritical fluids there is a Widom region, where some physicochemical properties such as density and compressibility exhibit anomalous behavior [14][15][16]. The Widom region is related to the critical pressure and critical temperature, which is 7.38 MPa and 31.04 • C, respectively for CO 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Figures[13][14][15] show the average reservoir pressure, mixed zone thickness, and CO2 concentration in produced gas over 15 years of operation under different temperatures, respectively. Logically, temperature had a positive influence on reservoir pressure change, and the cyclical changes were synchronized with the operation scenarios (Figure3).…”

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confidence: 99%

Utilization of CO2 as Cushion Gas for Depleted Gas Reservoir Transformed Gas Storage Reservoir

et al. 2020

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Underground gas storage reservoirs (UGSRs) are used to keep the natural gas supply smooth. Native natural gas is commonly used as cushion gas to maintain the reservoir pressure and cannot be extracted in the depleted gas reservoir transformed UGSR, which leads to wasting huge amounts of this natural energy resource. CO2 is an alternative gas to avoid this particular issue. However, the mixing of CO2 and CH4 in the UGSR challenges the application of CO2 as cushion gas. In this work, the Donghae gas reservoir is used to investigate the suitability of using CO2 as cushion gas in depleted gas reservoir transformed UGSR. The impact of the geological and engineering parameters, including the CO2 fraction for cushion gas, reservoir temperature, reservoir permeability, residual water and production rate, on the reservoir pressure, gas mixing behavior, and CO2 production are analyzed detailly based on the 15 years cyclic gas injection and production. The results showed that the maximum accepted CO2 concentration for cushion gas is 9% under the condition of production and injection for 120 d and 180 d in a production cycle at a rate of 4.05 kg/s and 2.7 kg/s, respectively. The typical curve of the mixing zone thickness can be divided into four stages, which include the increasing stage, the smooth stage, the suddenly increasing stage, and the periodic change stage. In the periodic change stage, the mixed zone increases with the increasing of CO2 fraction, temperature, production rate, and the decreasing of permeability and water saturation. The CO2 fraction in cushion gas, reservoir permeability, and production rate have a significant effect on the breakthrough of CO2 in the production well, while the effect of water saturation and temperature is limited.

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“…Figure 3 shows the steps of modelling proceeded for PE-ORC, ORC, superheated ORC, and TCO2C where the vapour quality (i.e., the ratio of the mass of vapour to the total mass of working fluid) at the end of the expansion ( ) is varied from 0.56 to 1.00. The TCO2C with = 0.56 (see Figure 3(a)) is developed to see the efficiency obtained in the very close vicinity of the critical point (due to the elevated density fluctuations in this region [21], crossing the critical point is technically almost impossible). The temperature of the condenser is fixed at 224.41 K, and the starting temperature of the expansion varies between 274.41 K and 500 K. Only the cycles formed below critical pressure are considered as TFC, PE-ORC, and ORC.…”

Section: Systems Models and Mathematical Descriptionmentioning

confidence: 99%

The efficiency of transcritical CO₂ cycle near critical point and with high temperature

2021

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Efficiency is a key parameter used to assess the quality of operation of power generation systems and devices applied for converting one type of energy to the other. Although, in the end, an investment project is mainly evaluated by economic aspect. Furthermore, many researchers have been investigating the possible types of energy conversion systems and devices applied for power generation and utilizing different types of working fluids. This paper presents the inside into transcritical carbon dioxide (CO2) cycle and the gradients of its efficiency. Transcritical CO2 cycle (TCO2C) here refers to a CO2-based thermal power generation cycle absorbing heat from a heat source (ideally with constant pressure) till the supercritical state is reached. It is followed by an expansion to a sub-critical superheated or even two-phase (wet) state. As alternatives, trilateral flash cycle (TFC) and organic Rankine cycle (ORC) utilizing CO2 are also introduced in this paper. The calculation in this study is computed based on MATLAB integrated with thermophysical properties like CoolProp and REFPROP, the mathematical models of the system are built and calculated with the same heat sink temperature of 224.41 K, and the heat source temperature is varied between 274.41 K and 500 K. At a certain temperature, the obtained result shows that the efficiency of the TCO2C is lower than the efficiency of ORC. Another result proves that the quality of working fluid at the end of the expansion process significantly influences the efficiency of the cycle.

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Anomalous Properties of Some Fluids − with High Relevance in Energy Engineering − in Their Pseudo-critical (Widom) Region

Cited by 16 publications

References 24 publications

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

Utilization of CO2 as Cushion Gas for Depleted Gas Reservoir Transformed Gas Storage Reservoir

The efficiency of transcritical CO₂ cycle near critical point and with high temperature

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Anomalous Properties of Some Fluids − with High Relevance in Energy Engineering − in Their Pseudo-critical (Widom) Region

Cited by 16 publications

References 24 publications

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

Existence of Supercritical "Liquid-Like" State in Subcritical Region, Optimal Heat Transfer Enhancement, and Argon as a Nonreacting, Noncorroding Sc Heat Transfer Fluid

Utilization of CO2 as Cushion Gas for Depleted Gas Reservoir Transformed Gas Storage Reservoir

The efficiency of transcritical CO2 cycle near critical point and with high temperature

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The efficiency of transcritical CO₂ cycle near critical point and with high temperature