Supercritical Carbon Dioxide Research Articles

Measurement and Modeling of the Solubility of Mebeverine Hydrochloride in Supercritical Carbon Dioxide

AbstractMebeverine hydrochloride is an important drug to treat irritable bowel syndrome. The solubility of this drug in supercritical carbon dioxide was measured at temperatures from 35 to 65 °C and pressures from 12 to 30 MPa. Results were between 2.16 and 30.2 ppm by mole. The data were correlated with density‐based models (K‐J, MST, Chrastil, Garlapati and Madras, Bartle et al., and Sparks et al.) and equations of state (Peng‐Robinson, Soave, and Estévez et al. models). The mean relative deviation and corrected correlation coefficient were used to assess the goodness of the models. Based on all ten models, Sparks et al. performed best according to average absolute relative deviation (5.64 %), and Bartle et al. was the best according to Radj (0.997). However, this contribution's main merit is the reported experimental data.

Supercritical Carbon Dioxide Extraction of Citronella Oil Review: Process Optimization, Product Quality, and Applications

This review paper explores the utilization of supercritical carbon dioxide (SC-CO2) extraction to isolate citronella oil, delving into its multifaceted dimensions, including process optimization, product quality enhancement, and diverse potential applications. Citronella oil, renowned for its myriad bioactive compounds with demonstrated health benefits, is a coveted essential oil in the pharmaceutical, cosmetics, and food industries. The transition from traditional extraction techniques to SC-CO2 extraction presents a paradigm shift due to its manifold advantages, such as heightened yield rates, expedited extraction durations, and elevated product quality. However, the efficacy of SC-CO2 extraction is intricately interwoven with an array of parameters encompassing pressure, temperature, flow rate, particle size, and co-solvent ratios. Accordingly, meticulous process optimization is indispensable in achieving the desired product quality while maximizing yield. Furthermore, the paper explores the extensive spectrum of potential applications for citronella oil, extending its reach into formulations with antimicrobial, insecticidal, and antioxidant properties. These applications underscore the versatility and commercial appeal of citronella oil. The review establishes SC-CO2 extraction of citronella oil as a promising and sustainable alternative to conventional extraction methodologies, offering myriad applications across the pharmaceutical, cosmetics, and food sectors. This scholarly work provides valuable insights into the intricacies of process optimization and product quality. It outlines future perspectives and avenues for further exploration in SC-CO2 extraction of citronella oil.

Determination of Regorafenib monohydrate (colorectal anticancer drug) solubility in supercritical CO2: Experimental and thermodynamic modeling

In this study, the solubilities of Regorafenib monohydrate (REG), a widely used as a colorectal anticancer drug, in supercritical carbon dioxide (ScCO2) were measured under various pressures and temperature conditions, for the first time. The minimum value of REG in mole fraction was determined to be 3.06×10−7, while the maximum value was found to be 6.44×10−6 at 338 K and 27 MPa. The experimental data for REG were correlated through the utilization of two types of models: (1) a set of 25 existing empirical and semi-empirical models that incorporated 3–8 parameters according to functional dependencies, (2) a model that relied on solid-liquid equilibrium (SLE) and the newly improved association models. All of the evaluated models were capable of generating suitable fits to the solubility data of REG, however, the average absolute relative deviation (AARD) of Gordillo et al. model (AARD=13.2%) and Reddy et al. model (AARD=13.5%) indicated their superiority based on AARD%. Furthermore, solvation and sublimation enthalpies of REG drug were estimated for the first time.

Policosanols from grape marc: A new step towards a sustainable biorefinery for the wine industry by SC-CO2 extraction

Supercritical carbon dioxide (SC-CO2) extraction of policosanol (PC) from grape marc was investigated for the first time. Employing the broken plus intact cells (BIC) model (Sovová's model) the investigation focused on analyzing the SC-CO2 process to extract the nonpolar fraction from grape marc efficiently. Operating conditions for SC-CO2 extraction—280 bar pressure, 70 °C temperature, and a flow rate of 10 kgCO2/h—yielded the highest policosanol content. The extracted policosanol ranged between 3922 and 4083 mg/kgDM, constituting approximately 8 % of the total extraction yield. Surprisingly, this amount of PC was of the same order of magnitude found in beeswax yellow, a well-known rich natural source of PC. The primary aliphatic alcohols found in the PC from grape marc were hexacosanol, octacosanol, and triacontanol. These findings were consistent with grape marc samples from other Italian regions. Furthermore, a comparative analysis between SC-CO2 and Soxhlet extraction methods for PC was carried out.

A Mini-review on the Chemical Composition, Extraction and Isolation Techniques, and Pharmacological Activity of Rosmarinus officinalis L.

Abstract: Rosmarinus officinalis L. belongs to the genus Rosemary in the family Labiatae, which is a perennial evergreen subshrub. It is currently cultivated in certain areas of Yunnan, Guangxi, and Guizhou. At present, in food, cosmetics, healthcare products, and other domains, R. officinalis has a wide range of applications; it has received widespread attention, and is also a hot topic of research today. Using modern spectroscopic techniques, it has been found that the main chemical components of rosemary can be divided into two major groups, including volatile components (essential oils) and non-volatile components (diterpenes, triterpenes, flavonoids, phenolic acids, sterols, etc.). Among them, carnosic acid, carnosol, rosemary phenol, and 1,8-cineole are the main components acting as antioxidants and they are highly regarded. The main methods for extracting the active ingredients of R. officinalis include water distillation, ultrasonic-assisted microwave method, supercritical CO2 extraction method, enzyme-assisted extraction method, and microwaveassisted extraction method. Modern research has shown that rosemary has anti-inflammatory, antioxidant, antibacterial, antiviral, antitumor, hepatoprotective, hypolipidemic, immunomodulatory, antiseptic, and antithrombotic effects, and is widely used in medical applications.

Supercritical CO2 Treatment of Mixed Matrix Membranes Based on Polyimides for Improvement of Their Gas Transport Properties

Supercritical CO2 Treatment of Mixed Matrix Membranes Based on Polyimides for Improvement of Their Gas Transport Properties

Process Reduces Carbon Emissions From Natural Gas Compression and Production

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214974,“New Technology Reduces Carbon Emissions From Natural Gas Compression and Production Facilities,” by John Guoynes, SPE, David Stiles, SPE, and Cory Vail, Axip Energy Services, et al. The paper has not been peer reviewed. _ A chemical-free process has been developed to capture exhaust from natural gas drive compressors and supporting gas-fueled production equipment while featuring a small footprint. The process separates CO2 and nitrogen from exhaust, allowing the CO2 to be discharged at high pressure for transport, sequestration, or enhanced oil recovery. Introduction Over 50,000 compressors move natural gas in North America. Most are driven by either internal combustion engines or turbines. These compressors produce am estimate of more than 30 million tonnes of CO2 equivalent yearly, according to the US Environmental Protection Agency’s Greenhouse Gas (GHG) Reporting Program. The significance of GHG reduction policies has heightened with the passing of the Inflation Reduction Act, which provides support for companies investing in future carbon capture use and storage, along with methane reduction. Process Modeling Modeling and analysis of an exhaust-gas carbon capture system, and the design and optimization of a supercritical CO2 (sCO2) waste-heat-recovery power cycle, was performed. This cycle was chosen for its high efficiency and relatively compact design compared with competitive waste-heat-recovery technologies. The preliminary process-flow diagram was provided based on conditions for 30,000-hp large reciprocating gas engines. Several process configurations were investigated; these iterations are detailed in the complete paper. A summary of this development shows that Iterations 1 through 3 showed improvements in power through improving the sCO2 power-cycle efficiency. However, this came at the increase in high-pressure sCO2 components. A simplification of components returned the sCO2 cycle to a single cascaded cycle in Iterations 4 through 5. Temperature selection in the sCO2 cycle also improved its efficiency. Moving to Iteration 4 improved the system power requirement by 20.7%. Iteration 5 showed moderately reduced performance over Iteration 4. This was the result of shifting more duty to the ammonia chillers and a moderate worsening of performance in the gas compressor. Iteration 5 did not improve the power requirement of the system. Ultimately, Iteration 4 was the most-efficient cycle evaluated with the overall lowest power requirement. Exhaust-Capture Decarbonization System The system developed captures exhaust from compression and other internal combustion equipment commonly used in gas transmission, oil and gas production, and midstream applications. The system works with a chemical-free, cryogenic design with a small modular footprint to capture large volumes of exhaust gas at atmospheric pressure. This technology separates CO2 and nitrogen, generates enough power from waste heat to run the equipment, and discharges captured CO2 under high pressure at supercritical conditions for compressor stations of 5,000 to 20,000 hp. The design is fully self-contained and mounts on a compact skid package capable of handling up to 70 million scf/D of exhaust while extracting liquid CO2 from rich-burn driven compressors, lean-burn driven compressors, or turbines.

Employment of artificial intelligence approach for optimizing the solubility of drug in the supercritical CO2 system

This paper investigates the solubility behavior of digitoxin in supercritical carbon dioxide (CO2) through a comprehensive analysis employing ensemble learning techniques and various regression models. The dataset consists of temperature and pressure as input variables, with solvent density and digitoxin solubility as output variables. Utilizing bagging as the ensemble method, Gaussian process regression (GPR), Bayesian Ridge Regression (BRR), Orthogonal Matching Pursuit (OMP), and Polynomial Regression (PR) were employed as regression models. Hyper-parameter tuning was achieved through gradient-based optimization. Results revealed that Polynomial Regression (PR) emerges as the most effective model for predicting both solvent density and digitoxin solubility. For solubility prediction, BAG-PR yields an R2 score of 0.98527, with MSE and MAE of 1.4290E-03 and 3.40547E-02, respectively. Concerning solvent density, BAG-PR achieves an outstanding R2 of 0.99766, along with MSE and MAE of 7.4759E+01 and 7.33964E+00, respectively. These results show that ensemble learning, and polynomial regression can accurately predict solubility and solvent density, revealing digitoxin's behavior in supercritical CO2.

Solubility of o-toluidine in supercritical carbon dioxide at high-temperatures and high-pressures

In many technological applications the solubility (VLE data) of materials (solid or liquids) in SC CO2 is required. It is essential to understand the solubility and other properties of o-toluidine in the SC CO2 due to their technological importance. This paper presents a new isothermal VLE data for SC CO2 (1)+ o-toluidine (2). Thus, the main purpose of the present work is to experimental study of the VLE properties (solubility, PTxy relationship) of o-toluidine (one of the technologically important compound) in the SC CO2 needs for variety industrial applications. The measurements were made at four selected isotherms of (313.15, 333.15, 353.15, and 373.15) K over the pressure range from (1.24 to 31.44) MPa. A high-temperature and high-pressure optical cell has been used to measure of the phase equilibrium properties (PTxy) of the binary CO2 (1)+ o-toluidine (2) mixture. The combined expanded absolute and relative uncertainty of the temperature, pressure, and the phase concentration measurements at 0.95 confidence level with a coverage factor of k = 2 is estimated at 0.15 K, 0.2 %, and 3 %, respectively. The critical point parameters of the mixture in the PC−TC projection have been estimated using the measured VLE data. The shape of the critical curve behavior indicates that CO2 (1) + o-toluidine (2) mixture belongs to the Type III according to the Konynenburg and Scott classification. PR and PC-SAFT equation of state (EoS) were successfully applied to model the phase equilibria (qualitative point of view) for the SC CO2 (1) + o-toluidine (2) mixture at the measured experimental temperatures. From a quantitative point of view, the best choice (among the models used) was PR EoS. The critical curves predicted with PR and PC-SAFT EoS confirmed that the mixture is classified as Type III phase behavior.

Effect of Esterification of Natural Dyes with Glycosides on Dyeing Properties of Natural Fibers in Supercritical Carbon Dioxide

Effect of Esterification of Natural Dyes with Glycosides on Dyeing Properties of Natural Fibers in Supercritical Carbon Dioxide

Supercritical carbon dioxide cycle thermodynamic and exergoeconomic improvements using a bidirectional coupling strategy

Supercritical carbon dioxide (SCO2) combined cycle power system, one of the potentially effective ways to achieve energy grade utilization of the medium and high-temperature heat sources, is vulnerable to ambient temperatures as the system performance is susceptible to the compressor inlet temperature. So far, most studies have been focused on the system performance analysis and optimization under ideal operation conditions while the mitigation of unfavorable ambient temperature is missed. In this work, a bidirectionally-coupled system is proposed to reduce the compressor inlet temperatures in the original SCO2 cycle power system so that the adverse effects of ambient temperature are alleviated. The proposal utilizes the low-grade waste heat in a SCO2 recompression reheat Brayton cycle (i.e., topping cycle) to drive an absorption refrigeration cycle (i.e., bottoming cycle) which in turn precools the compressor inlet of the topping cycle. The thermodynamic and exergoeconomic analyses have been conducted for the proposed bidirectionally-coupled combined SCO2 RRBC and ARC system, with the attention to the effects of ambient temperatures on the system performance. Our results show that the combined SCO2 RRBC and ARC system increases the energy efficiency relative to the standalone cycle power system by over 5% at the ambient temperatures of 303.15 K or above, while the exergy efficiency improves by 1.124%–3.574%. In terms of the exergoeconomic factor, the combined SCO2 RRBC and ARC system also exhibits superiority against standalone cycle power system. The current work proves that a conventional recuperated SCO2 cycle system can be improved both thermodynamically and economically by coupling it to an absorption refrigeration cycle, despite of the additional upfront costs for the components. The discovery could further promote the commercial application of the SCO2 cycle power systems in new generation plants.

Comparison of antimicrobial activities of oregano, lavender, sage, anise and clove extracts obtained by supercritical fluid carbon dioxide extraction and essential oils obtained by hydrodistillation

ABSTRACT The aim of the study was to compare the extraction yields, chemical compositions and antimicrobial activities of essential oils obtained by hydrodistillation (HD) and volatile extracts obtained by supercritical fluid extraction extraction (SFE) from oregano (Origanum onites), lavender (Lavandula angustifolia), sage (Salvia officinalis), anise (Pimpinella anisum) and clove (Syzygium aromaticum). Essential oil compounds (EOCs) of the obtained materials from both techniques (HD and SFE) were determined by GC-MS/FID. Agar well diffusion method was used for the determination of antimicrobial activities on five different foodborne microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli Enterococcus faecalis and Klebsiella pneumoniae). According to the results; extraction yields of SFE were found to be higher than HD for all tested aromatic plants. Active ingredient ratios (carvacrol, camphor, anethole, eugenole and linalol) varied depending on the extraction methods. SFE extracts were higher antimicrobial activity than HD essential oils, except clove extract on E. faecalis.

A comprehensive multi-variable approach for evaluating the feasibility of integration a novel heat recovery model into a gas turbine power plant, producing electricity, heat, and methanol

Considering the importance of efficient thermal integration for a gas turbine cycle using its energetic flue gas, the current paper proposes an eco-friendly and efficient process integrated into a gas turbine cycle. The newly designed polygeneration structure produces power, hot water, and methanol. The components of this system include a heat provider unit, a direct carbon dioxide hydrogenation unit for the production of methanol, an ammonia Rankine cycle, a proton exchange membrane electrolyzer, a supercritical carbon dioxide power cycle, and two organic Rankine cycles. The feasibility of the proposed model is evaluated using a comprehensive multi-variable assessment from energy, exergy, economic, and environmental approaches. This system exhibits a power production capacity of 17197.23 kW and a methanol generation rate of 0.7573 kg/s. Also, the total irreversibility is equal to 68161.18 kW. Besides, the total energy and exergy efficiencies are found as 68.73% and 32.03%, respectively. This model's carbon dioxide emission is 18667.36 kgCO2/h, and its carbon footprint equals 0.2196 kgCO2/kWh. Furthermore, the economic analysis reveals that the project has an annual total cost of 194,602,338 and a net present value of 686,221,616. Besides, the computed total unit costs for products and energy are 0.3385 $/kWh and 89.81 $/GJ, respectively.

Effect of Operational Variables on Supercritical Foaming of Caffeic Acid-Loaded Poly(lactic acid)/Poly(butylene adipate-co-terephthalate) Blends for the Development of Sustainable Materials.

Expanded polystyrene will account for 5.3% of total global plastic production in 2021 and is widely used for food packaging due to its excellent moisture resistance and thermal insulation. However, some of these packages are often used only once before being discarded, generating large amounts of environmentally harmful plastic waste. A very attractive alternative to the conventional methods used for polymer processing is the use of supercritical carbon dioxide (scCO2) since it has mass-transfer properties adapted to the foam morphology, generating different path lengths for the diffusion of active compounds within its structure and can dissolve a wide range of organic molecules under supercritical conditions. The objective of this research was to evaluate the effect of operational variables on the process of caffeic acid (CA) impregnation and subsequent foaming of polylactic acid (PLA) as well as two PLA/poly(butylene-co-terephthalate-adipate) (PBAT) blends using scCO2. The results showed an increase in the degree of crystallinity of the CA-impregnated samples due to the nucleation effect of the active compound. On the other hand, SEM micrographs of both films and foams showed significant differences due to the presence of PBAT and its low miscibility with PLA. Finally, the results obtained in this work contribute to the knowledge of the important parameters to consider for the implementation of the impregnation and foaming process of PLA and PLA/PBAT blends with potential use in food packaging.

Raziskave o trajnostni proizvodnji tekstila: brezvodno barvanje poliestrskih in recikliranih poliestrskih tkanin

Due to water limitations and the growing global demand for raw materials, manufacturers and consumers are seeking more environmentally friendly alternatives. Polyester, a non-biodegradable fibre derived from petroleum, can be replaced with recycled polyester (r-PET), a sustainable alternative that reduces environmental impacts through the reuse of materials. The textile finishing industry, known for its high water and energy consumption, is calling for the development of low-water-consumption technologies. One innovative approach involves waterless dyeing procedures using a supercritical carbon dioxide (scCO2) medium that is particularly suitable for dyeing synthetic fibres. To assess its effectiveness, a study compared traditional water dyeing with scCO2 medium dyeing on woven fabrics made from both polyester (PET) and recycled polyester (r-PET) fibres with varying weights. After conducting tests on the dyed fabrics, the data revealed that r-PET fabrics dyed using a supercritical carbon dioxide (scCO2) medium appeared darker than fabrics dyed using traditional water dyeing techniques. Moreover, r-PET fabrics demonstrated better colour fastness. Notably, the K/Ssum values (measurement of colour intensity) of r-PET fabrics were at least as good as those of PET-based fabrics in all cases of dyeing, while the fastness values were similar for both PET and r-PET fabrics.

A green approach to efficient soil decontamination using supercritical carbon dioxide and ethanol

As the need for global decommissioning and site remediation of aging and shut-down nuclear power plants continues to grow, it becomes increasingly crucial to efficiently treat contaminated soil while minimizing waste generation. This study explores an innovative soil decontamination approach that utilizes supercritical carbon dioxide (SCCO₂) as the primary solvent, along with ethanol as a co-solvent and specific additives, including a chelate ligand (catechol ligand) and a co-ligand (NEt₄PFOSA). The advantages of SCCO₂, such as its penetration and solubility, coupled with its ability to separate from radioactive waste, are harnessed in this research. The study demonstrates that the combination of SCCO₂, ethanol, and additives significantly enhances decontamination efficiency, particularly for cesium (Cs), strontium (Sr), and uranium (U) contamination. Results indicate that decontamination efficiency varies with soil particle size, with smaller particles presenting greater challenges. This study presents a promising eco-friendly soil decontamination technology using SCCO₂ containing ethanol and specific additives to efficiently reduce radioactive contamination in soil.

Numerical Simulation of Flow Characteristics for Supercritical CO2-Sprayed Polyurethane Resin.

Conventional paint spraying processes often use small molecule organic solvents and emit a large amount of volatile organic compounds (VOCs) that are highly toxic, flammable, and explosive. Alternatively, the spraying technology using supercritical CO2 (scCO2) as a solvent has attracted attention because of its ability to reduce VOC emissions, but the flow characteristics of coatings have not been thoroughly studied. Therefore, we numerically simulate the spraying process based on the actual process of scCO2 spraying polyurethane coatings by computational fluid dynamics (CFD). The effects of inlet pressure and volume fraction of scCO2 on the fluid motion parameters inside the nozzle as well as the atomization effect of droplets outside the nozzle are investigated. The simulated results show that a fluid with a large volume fraction of scCO2 will obtain a smaller density, resulting in a larger velocity and a larger distance for the spray to effectively spray. Higher coating content and bigger inlet pressures will result in higher discrete phase model (DPM) concentrations, and thus a bigger inlet pressure should be used to make the droplets more uniform across the 30° spray range. This study can provide theoretical guidance for the process of scCO2-sprayed polyurethane resin.

Efficiency of Supercritical CO2 and Ultrasound-Assisted Extraction Techniques for Isolation of Bioactive Molecules from Sea Buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) Berry Oils and Cakes

This study compared the efficiency of advanced supercritical CO2 extraction (SC-CO2) and conventional Soxhlet extraction (SE) in the isolation of lipophilic bioactive molecules (BAMs) from the oils of different sea buckthorn (SB) berries (Leikora and Ascola). A SB cake, a valuable by-product of oil extraction, was analyzed for phenolic compounds and antioxidant activity (AA). For this purpose, ultrasound-assisted extraction (UAE) with 70% (v/v) ethanol was optimized, and the following optimal UAE conditions were determined: ultrasonic power of 60%, temperature of 50 °C, and extraction time of 20 min. The individual BAMs in the oils and cake extracts were analyzed chromatographically, while the AAs were determined using the ORAC method. The oils extracted with SC-CO2 had a higher content of lipophilic BAMs and a higher AA value than the oils extracted with SE. Palmitic and palmitoleic acids, β-sitosterol, and α-tocopherol dominated the Leikora oil, while a higher content of oleic, linoleic, and α-linolenic acids and carotenoids was found in the Ascola oil. The highest phenolic content was found in the Ascola cake, with the flavonols isorhamnetin-3-hexoside, isorhamnetin-3-rutinoside, and quercetin-3-glucoside being the most abundant. Oil and cake extracts of the Ascola variety also had a higher AA.

Thermo-hydraulic characteristics and structural optimization of supercritical CO2-cooled microchannel heat sink

Supercritical carbon dioxide (sCO2) serves as an efficient working fluid in microchannel heat sinks (MCHS), effectively mitigating heat dissipation challenges in high heat flux microelectronic devices. Nonetheless, the issue of flow acceleration affecting micro-scale heat transfer, especially in channels with diameters <0.2 mm, warrants additional investigation. Flow acceleration exacerbates temperature non-uniformity, consequently diminishing heat transfer efficiency. Numerical simulations were conducted to examine the thermo-hydraulic characteristics of sCO2 in microchannels featuring complex structures including ribs and cavities. The channel had a diameter of 0.133 mm, with heat flux to mass flow rate (q/G) ranging from 0.1 to 0.5 kJ/kg. Three-dimensional entropy production rate (Sg) maps and corresponding heat maps were utilized to establish boundary conditions and evaluate heat transfer optimization. Additionally, structural optimizations were performed to rectify temperature non-uniformity in sCO2 within MCHS. The results indicate that the entropy production rate (Sg) of sCO2 initially decreased and then increased with the increase in q/G and dimensionless enthalpy (h*). The optimized MCHS demonstrated enhanced temperature uniformity, with a maximum temperature difference of 1.8 K, notably lower than that of the non-optimized MCHS (5.3 K). This study offers a theoretical basis for the design and implementation of sCO2 in micro-scale MCHS.

Parameters analysis and techno-economic comparison of various ORCs and sCO2 cycles as the power cycle of Lead–Bismuth molten nuclear micro-reactor

Organic Rankine cycle (ORC) and supercritical CO2 (sCO2) Brayton cycle are two key and competition technology routes as the power cycle of Lead–Bismuth micro-reactor (LBMR). However, few studies focus on the comparison of thermodynamic and economic performance between ORCs and sCO2 cycles in nuclear micro-reactor. The objectives in this study are to perform parameters analysis and techno-economic comparison in ORCs and sCO2 cycles with various configurations as the power cycle of LBMR, so as to provide the technical support for the selection of power cycle and its operating conditions in different scenarios. Several high/low-temperature working fluids are screened for ORCs in view to achieve high net efficiency (ηth) and low electricity production cost (EPC). Multi-objective optimization is performed to solve the trade-off between ηth and EPC, and then to compare the comprehensive performance of various cycles from thermodynamic, compact and economic aspects. Results show that, the ηth and EPC of ORCs are comparable or superior to that in sCO2 cycles when the two cycles have similar structures (simple/regenerative). Among the ORCs, the cascade ORC with two-side regeneration using N-Dodecane/Pentane as working fluid pair has the best performance. In all cycles, recompression sCO2 cycle performs best, but only when the heat source temperature is higher than 460 °C, the performance of the recompression sCO2 cycle are overall better than the cascade ORC.