Volume 9: Supercritical CO2最新文献

{"title":"Specific Speed Considerations for Inward Flow Radial Supercritical CO2 Turbines","authors":"S. J. Hoque, Pramod Kumar, P. Gopi","doi":"10.1115/gt2022-82090","DOIUrl":"https://doi.org/10.1115/gt2022-82090","url":null,"abstract":"\u0000 Inward flow radial supercritical CO2 turbines require higher operating speeds than steam or gas turbines making only low specific speed designs practically realizable. A theoretical model is presented to estimate the low specific speed design regime. The model incorporates boundary conditions across the turbine and engineering limitations such as blade height, Mach number, and flow angle at the rotor inlet to predict the minimum allowable rotational speed. A CFD study is subsequently performed to review the applicability of gas turbine design principles on sCO2 turbines for low specific speed designs. The effect of specific speed and velocity ratio on turbine efficiency and flow physics is studied for power output ranging from 100 kW to 5 MW. The results show a significant deviation in the optimal specific speed, velocity ratio, and incidence angle values than traditional gas turbine designs. It is found that viscous losses dominate low specific speeds, while Coriolis effects dominate the high specific speed designs. High specific speed designs require higher negative incidence angles ∼ −50° to −55° to overcome the flow stagnation at blade pressure surface arising from the Coriolis effect. Maximum turbine efficiencies (∼ 83%) are achieved at lower specific speeds of ∼ 0.4 than gas turbines’ optimal specific speed of ∼ 0.55 to 0.65. Variations of stator, rotor, and exit kinetic energy losses with specific speeds are also presented. Finally, the results are superposed on Balje’s Ns-Ds diagram and compared with gas turbine designs.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132718412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preliminary Analysis of High-Temperature Corrosion of Metallic Alloys With CO2 and CO2-Based Working Mixtures for Power Plants Applications","authors":"Lorenza Putelli, G. Di Marcoberardino, M. Gelfi, C. Invernizzi, P. Iora, G. Manzolini","doi":"10.1115/gt2022-84197","DOIUrl":"https://doi.org/10.1115/gt2022-84197","url":null,"abstract":"\u0000 CO2 has been proposed in the past decades as a suitable working fluid in power plants. One way to reduce costs is to use carbon dioxide blends instead. There is a lack of knowledge about the behavior of sCO2 blending in the interaction with commercial alloys at high temperatures, so this aspect must be strictly considered. A preliminary study has been performed considering the oxidation behavior of some Ni-based and Fe-based alloy (i.e., alloy 625, AISI 304, and AISI 316) in different conditions. In each case, the oxidation layer developed on the alloy surface was investigated by scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The analysis was also performed on the cross-section of the sample to evaluate the penetration depth of damage. The results show that the interaction with fluorine-containing compounds is more corrosive than pure CO2. This confirms that although the mixture improves the thermodynamic efficiency of the cycle, their compatibility with materials must be carefully investigated. However, in all the cases studied, in the test conditions, the preliminary analysis doesn’t recommend the use of the tested materials.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117048000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygen Storage Incorporated Into Net Power and the Allam-Fetvedt Oxy-Fuel sCO2 Power Cycle – Technoeconomic Analysis","authors":"J. Moore, Owen M. Pryor, Ian Cormier, J. Fetvedt","doi":"10.1115/gt2022-82060","DOIUrl":"https://doi.org/10.1115/gt2022-82060","url":null,"abstract":"\u0000 With the planned future reliance on variable renewable energy, the ability to store energy for prolonged time periods will be required to reduce the disruption of market fluctuations. This paper presents a method to analyze a hybrid liquid-oxygen (LOx) storage / direct-fired sCO2 power cycle and optimize the economic performance over a diverse range of scenarios. The system utilizes a modified version of the NET Power process to produce energy when energy demand exceeds the supply while displacing much of the cost of the ASU energy requirements through cryogenic storage of oxygen. The model uses marginal cost of energy data to determine the optimal times to charge and discharge the system over a given scenario. The model then applies ramp rates and other time-dependent factors to generate an economic model for the system without storage considerations. The size of the storage system is then applied to create a realistic model of the plant operation. From the real plant operation model, the amount of energy charged and discharged, the CAPEX of each system, energy costs and revenue and other parameters can be calculated. The economic parameters are then combined to calculate the net present value (NPV) of the system for the given scenario. The model was then run through the SMPSO genetic algorithm in Python for a variety of geographic regions and large-scale scenarios (high solar penetration) to maximize the NPV based on multiple parameters for each subsystem. The LOx storage requirements will also be discussed.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125568335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Part-Load Behaviour and Control Philosophy of a Recuperated Supercritical CO2 Cycle","authors":"Lorenzo Gini, Simone Maccarini, A. Traverso, E. Pesatori, A. Milani, V. Bisio, Roberto Valente, S. Barberis, R. Guédez","doi":"10.1115/gt2022-83021","DOIUrl":"https://doi.org/10.1115/gt2022-83021","url":null,"abstract":"\u0000 High efficiency, flexibility and competitive capital costs make supercritical CO2 (sCO2) systems a promising technology for renewable power generation in a low carbon energy scenario. Recently, innovative supercritical systems have been studied in the literature and proposed by DOE-NETL (STEP project) and a few projects in the EU Horizon 2020 program aiming to demonstrate supercritical CO2 Brayton power plants, promising superior techno-economic features than steam cycles particularly at high temperatures.\u0000 The H2020 SOLARSCO2OL project1, which started in 2020, is building the first European MW-scale sCO2 demonstration plant and has been specifically tailored for Concentrating Solar Power (CSP) applications. This paper presents the first off-design analysis of such a demonstrator, which is based on a simply recuperated sCO2 cycle. The part-load analysis ranged from 50% of nominal up to a 105% peak load, discussing the impact on compressor and turbine operating conditions. The whole system dynamic model has been developed in TRANSEO MATLAB® environment. Full operational envelop has been determined considering cycle main constraints, such as maximum turbine inlet temperature and minimum pressure at compressor inlet.\u0000 The off-design performance analysis highlights the most relevant relationships among the main part-load regulating parameters, namely mass flow rate, total mass in the loop, and available heat source. The results show specific features of different control approaches, discussing the pros and cons of each solution, considering also its upscale towards commercial applications. In particular, the analysis shows that at 51% of load an efficiency decrease of 20% is expected.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114490967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative Expanders for Supercritical Carbon Dioxide Cycles","authors":"Alessandro Perri, Avinash Renuke, A. Traverso","doi":"10.1115/gt2022-83116","DOIUrl":"https://doi.org/10.1115/gt2022-83116","url":null,"abstract":"\u0000 Supercritical carbon dioxide plants are attracting strong interest, particularly for distributed power generation, thanks to the high-power density, allowing high compactness and efficiencies due to the particular features of the fluid conditions near the critical point. In the present work, the feasibility of innovative turboexpanders is evaluated for the first European demonstrator of MW size, coupling small volumetric flows with technological simplicity, typical of these types of plants. In particular, the possibility of replacing conventional turbines with bladeless expanders is studied, proposing a design in line with those achievable by small radial and axial turbomachines. The bladeless expanders consist of flat parallel disks mounted on a shaft, separated by spacers to maintain small gaps between them. The laminar flow inside the rotor makes it highly efficient: however, rotor-stator interaction losses reduce the overall performance. Such bladeless expanders maintain high interest for their capability to tackle low volumetric flows, their relatively simple design and ease of manufacturability.\u0000 The design case presented in this paper is the feasibility study of a single modular bladeless expander using the existing conventional design (axial and radial stages) as the reference design. 3D numerical analysis is carried out using commercial computational fluid dynamic software. The results show ∼55% total static efficiency of the bladeless expander at 37000 rpm for approximately 1.25MW output power. The impact on performance at different nozzle throat cross-sections and rotor disks diameter has been discussed. The overall performance of the expander is presented by evaluating the losses and improvement strategies that are discussed.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121973948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Update of the sCO2-Test Rig at Cranfield University","authors":"Eduardo Anselmi, P. Belleoud, I. Roumeliotis, V. Pachidis","doi":"10.1115/gt2022-83273","DOIUrl":"https://doi.org/10.1115/gt2022-83273","url":null,"abstract":"\u0000 Since 2018, there is an experimental supercritical carbon dioxide (sCO2) facility operating at Cranfield University. The purpose of this rig is to enable the exploration of supercritical carbon dioxide as a working fluid for future bottoming power cycle applications and, more recently, for thermal management applications. The core of the rig is a transcritical closed loop, which has recently been upgraded. The upgrades include an increase in the number of measurement stations, changes to the types of measurements taken, as well as the addition of a new, dedicated data acquisition system. A summary of some of the lessons learned from different test campaigns conducted from 2018 to 2021 is provided, along with a discussion on the measurement upgrades performed. The experience obtained with this rig, as recounted in this paper, could be relevant to similar test rigs or future power cycles applications.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130767637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Real Gas Properties on Loss in a Super Critical CO2 (sCO2) Centrifugal Compressor","authors":"Ruikai Cai, Mingyang Yang, K. Deng, W. Zhuge, Bijie Yang, R. Martinez-Botas, Tao Chen","doi":"10.1115/gt2022-82151","DOIUrl":"https://doi.org/10.1115/gt2022-82151","url":null,"abstract":"\u0000 The performance of the SCO2 centrifugal compressor is the key component influencing the efficiency and stability of the whole Close-Bryton cycle system. It is important to understand the loss mechanism inside the compressor to guide the design and performance optimization of the compressor. However, the physical properties of SCO2 are strongly nonlinear near the critical point, and the internal flow of the compressor is highly coupled with its properties, which inevitably profoundly influences the loss generation in the device. In this paper, the loss mechanism of SCO2 compressor is investigated comprehensively based on numerical method compared with experimental data. CO2 real gas model embodied in RANS model are used for the study. Firstly, grid independence and influence of the resolution of real gas properties tables are discussed. The numerical simulation results are in good agreement with the experimental data of Sandia SCO2 compressor. Secondly, the distribution of the loss of the compressor are evaluated by means of local entropy generation at different mass flow rates. In particular, a direction comparison between the cases with real gas properties and the constant properties is carried out for manifesting of the influence by real gas properties. The results manifest that the loss of the case with constant properties is profoundly higher than that of the real gas properties, especially at small flow rate. Detailed flow field is compared to understand the influence of the properties. It is shown that the tip leakage flow is evidently decreased with the real gas properties and results in a much more uniform flow distribution throughout the impeller. The decrease in static temperature and pressure due to the acceleration of SCO2 at the tip of the main blade causes an increase in fluid density, reducing the tip leakage and secondary flow. Moreover, the influence on the flow in the impeller results in smaller incidence angle near hub side for the case with real gas properties, thus the separation on the suction surface which happens in the case with constant properties is alleviated. Therefore, the loss in both the impeller and diffuser is significantly reduced by the real gas properties.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124220435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technoeconomic Comparison of sCO2 and ORC Systems for Waste Heat Recovery","authors":"T. Allison, Jason C. Wilkes, Karl D. Wygant, Rob Pelton","doi":"10.1115/gt2022-83434","DOIUrl":"https://doi.org/10.1115/gt2022-83434","url":null,"abstract":"\u0000 Various supercritical carbon dioxide (sCO2) power cycles are an emerging bottoming cycle technology for gas turbine waste heat recovery with potential advantages relative to Organic Rankine Cycle (ORC) systems, including improved performance, compactness, improved economics, nonhazardous working fluids, and faster ramp capabilities. This work compares a waste heat recovery system based on an integrally geared compander in a sCO2 preheat cycle configuration with split recuperator with a recuperated ORC in the literature. The integrally geared system is comprised of an 1800 rpm generator with high-pressure and low-pressure pinions splitting a two-stage compressor and expander. Cycle constraints and design drivers, and optimization of the sCO2 system are described, along with current technology readiness and full-pressure full-temperature opera ting experience of the various components including compressors, expanders, heat exchangers, and other system components. Both cycles are paired with a commercial 15 MW gas turbine, and the resulting system costs, performance, and other attributes are presented. The cycles are compared with an cold-side temperature of 35 °C, showing an ORC system output of 5066 kW and an sCO2 system output of 5660 kW, i.e. an 11.7 % performance benefit for sCO2. Additionally, cost and size requirements and costs for the sCO2 and ORC-based systems are compared, indicating comparable nominal costs for both systems and a potentially lower cost for sCO2 systems, particularly when an indirect heat transfer loop is needed.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"63 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132513012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Nitrogen Impurities on Oxy-Fuel Combustion Under Supercritical-CO2 Conditions","authors":"P. Gokulakrishnan, J. Shao, M. Klassen, D. Davidson, Ronald K. Hanson","doi":"10.1115/gt2022-81576","DOIUrl":"https://doi.org/10.1115/gt2022-81576","url":null,"abstract":"\u0000 The direct-fired supercritical-CO2 (sCO2) cycle has demonstrated the ability to produce clean energy by burning hydrocarbon feed stocks under oxy-fuel conditions. High-pressure operation of the direct-fired cycle allows for more economic extraction of CO2 for carbon capture and storage. However, the presence of nitrogen impurities in the oxidizer (i.e., N2) and in fuel feed stocks (e.g., NH3) can generate NOx in the exhaust. The presence of NOx in the recycled-CO2 stream can impact the combustion process as well as the structural integrity of the system. Also, even trace amounts of nitrogen oxides (considered acid gases) can be detrimental for CO2 capture, transportation and storage at supercritical conditions.\u0000 Therefore, it is critical to understand and accurately model the effects of nitrogen impurities on NOx formation and the impact of NOx in the recycled CO2 on combustion kinetics under oxy-fuel sCO2 conditions. It is also important to understand the effects of pressure with a sCO2 medium as the direct-fired sCO2 cycle operates up to 300 atm pressure. In this work, experimental and modeling work were performed to study the effect of nitrogen species on emissions as well as effect of NOx on ignition of CH4 and syngas fuels at sCO2 conditions. A chemical reactor network simulation was used to investigate the effects of nitrogen impurities in fuel and oxidizer stream on emissions from a direct-fired combustor condition. Monte Carlo simulations were also carried out to study the impact of model input variables on the emission profile.\u0000 High-pressure shock tube ignition delay time experiments were performed to investigate the effect of NOx on ignition at conditions relevant to direct-fired oxy-fuel sCO2 combustion. The ignition delay time measurements were made for syngas and CH4 fuels with and without NO addition using CO2 as bulk diluent at nominal pressures around 100 atm. Experimental data showed that the presence of NO promotes the ignition at the oxyfuel sCO2 combustion conditions. Reaction sensitivity analyses and model uncertainty analyses were conducted to identify important reactions and their rate uncertainty on the model predictions, respectively.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132143633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a 1MW Direct-Fired Oxy Combustor for sCO2 Power Cycles","authors":"Steve White, Grey Berry, B. Connolly","doi":"10.1115/gt2022-81747","DOIUrl":"https://doi.org/10.1115/gt2022-81747","url":null,"abstract":"\u0000 Direct-fired super-critical carbon dioxide (sCO2) power cycles are a potential method for efficiently capturing nearly all of the CO2 emissions from burning fossil fuels. Direct-fired sCO2 cycles require a very high degree of recuperation, which in turn means that the inlet temperature to the combustor is significantly higher than would typically be seen in a similar gas turbine combustor. Previous efforts have shown that combustor inlet temperatures of around 700°C at 200 bar are to be expected for a cycle with around 1200°C combustor exit temperatures.\u0000 The project team led by Southwest Research Institute is in the process of building and commissioning a 1MW scale direct-fired sCO2 oxy combustor. The test rig at SwRI uses laser ignition and advanced optical access to monitor combustion and characterize behavior. This paper will detail some of the challenges associated with the design and fabrication of the combustor and sCO2 power loop. These obstacles include thermal management, water generation, and constituent monitoring. The first ever unsteady simulations of this type of combustor were conducted as part of the design process. A presentation of the test rig layout, design considerations, and integration challenges will be covered.","PeriodicalId":105703,"journal":{"name":"Volume 9: Supercritical CO2","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133327670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}