N. Smith, Jason C. Wilkes, Jonathan L. Wade, T. Allison, Meera Day Towler, J. Moore, Ian Weinberg, Michael E Mccune
Gas compressor customers desire to operate gas compressors at higher discharge temperatures. In barrel-style centrifugal compressors, dry gas seals are used to limit the leakage along the shaft from the process fluid to atmosphere. The temperature limit of dynamic O-ring seals in the dry gas seal cartridge is one of the primary limiters to operating gas compressors at higher discharge temperatures. While the present discharge temperature limit is conservative compared to the seal limits, without a detailed understanding of the thermal distribution around the discharge-side end cap, operation at compressor discharge temperatures that exceed seal limits has too much risk. Thus, this paper describes the approach taken to characterize the temperatures around the discharge end dry gas seal of a commercial C335EL centrifugal compressor. A phased test matrix with increasing discharge temperatures was conducted so that the temperature distribution throughout the end cap could be assessed. The full-scale, highly-instrumented compressor was operated at discharge pressures and temperatures ranging from 4.7 to 9.4 MPa (680 to 1370 psi) and 113 to 218 degree Celsius (235 to 425 degrees Fahrenheit), respectively. The experimental test set-up and results are presented herein. Results include demonstration of successful compressor operation at discharge temperatures greater than seal limits as well as the end cap temperature sensitivity to lube oil supply and dry gas supply temperatures.
{"title":"Measurements of End Cap Temperatures in a Multistage Barrel-Style Centrifugal Compressor","authors":"N. Smith, Jason C. Wilkes, Jonathan L. Wade, T. Allison, Meera Day Towler, J. Moore, Ian Weinberg, Michael E Mccune","doi":"10.1115/gt2019-91798","DOIUrl":"https://doi.org/10.1115/gt2019-91798","url":null,"abstract":"\u0000 Gas compressor customers desire to operate gas compressors at higher discharge temperatures. In barrel-style centrifugal compressors, dry gas seals are used to limit the leakage along the shaft from the process fluid to atmosphere. The temperature limit of dynamic O-ring seals in the dry gas seal cartridge is one of the primary limiters to operating gas compressors at higher discharge temperatures. While the present discharge temperature limit is conservative compared to the seal limits, without a detailed understanding of the thermal distribution around the discharge-side end cap, operation at compressor discharge temperatures that exceed seal limits has too much risk. Thus, this paper describes the approach taken to characterize the temperatures around the discharge end dry gas seal of a commercial C335EL centrifugal compressor. A phased test matrix with increasing discharge temperatures was conducted so that the temperature distribution throughout the end cap could be assessed. The full-scale, highly-instrumented compressor was operated at discharge pressures and temperatures ranging from 4.7 to 9.4 MPa (680 to 1370 psi) and 113 to 218 degree Celsius (235 to 425 degrees Fahrenheit), respectively. The experimental test set-up and results are presented herein. Results include demonstration of successful compressor operation at discharge temperatures greater than seal limits as well as the end cap temperature sensitivity to lube oil supply and dry gas supply temperatures.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125136533","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}
Gas foil thrust bearings have been utilized in high speed lightweight machines for many decades. These bearings are environment-friendly and capable of withstanding extreme conditions. However, there are also some challenges for foil thrust bearings at high speed conditions, such as insufficient heat dissipation and thermal management. The heat generated by viscous shearing continues to raise the temperature inside the gas film and may cause failures. Among all the methods to enhance heat dissipation, a promising passive thermal management method is modifying the top foil’s trailing edge shape. This modification will enhance the air mixing in between the bearing pads. The aim of this study is to identify the optimal design of the top foil trailing edge shape and provide a guideline for future bearing design. A 3-D computational fluid dynamics (CFD) model for a thrust foil bearing was created using ANSYS-CFX software. The trailing edge of the top foil was modified to a chevron shape. A sensitivity study was conducted to investigate the connection between the top foil trailing edge shape and the thermal conditions in the gas film. The maximum temperature inside the air gas film is selected as the output. The design of experiments (DOE) technique was used to generate the sampling points. A surrogate model was generated based on the output data by using the neural network method. The surrogate model was used together with a genetic multi-objective algorithm to minimize the maximal temperature inside the gas film and maximize the load carrying capacity. The optimal design was then compared with the baseline model. Results suggest the optimized trailing edge shape is capable of reducing the temperature inside the gas film. This optimal design approach can be used for improvements of chevron foil thrust bearing design.
{"title":"Surrogate Model Based Optimization for Chevron Foil Thrust Bearing","authors":"A. Untăroiu, Gen Fu","doi":"10.1115/gt2019-90228","DOIUrl":"https://doi.org/10.1115/gt2019-90228","url":null,"abstract":"\u0000 Gas foil thrust bearings have been utilized in high speed lightweight machines for many decades. These bearings are environment-friendly and capable of withstanding extreme conditions. However, there are also some challenges for foil thrust bearings at high speed conditions, such as insufficient heat dissipation and thermal management. The heat generated by viscous shearing continues to raise the temperature inside the gas film and may cause failures. Among all the methods to enhance heat dissipation, a promising passive thermal management method is modifying the top foil’s trailing edge shape. This modification will enhance the air mixing in between the bearing pads.\u0000 The aim of this study is to identify the optimal design of the top foil trailing edge shape and provide a guideline for future bearing design. A 3-D computational fluid dynamics (CFD) model for a thrust foil bearing was created using ANSYS-CFX software. The trailing edge of the top foil was modified to a chevron shape. A sensitivity study was conducted to investigate the connection between the top foil trailing edge shape and the thermal conditions in the gas film. The maximum temperature inside the air gas film is selected as the output. The design of experiments (DOE) technique was used to generate the sampling points. A surrogate model was generated based on the output data by using the neural network method. The surrogate model was used together with a genetic multi-objective algorithm to minimize the maximal temperature inside the gas film and maximize the load carrying capacity. The optimal design was then compared with the baseline model. Results suggest the optimized trailing edge shape is capable of reducing the temperature inside the gas film. This optimal design approach can be used for improvements of chevron foil thrust bearing design.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123113807","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}
This paper presents a transcritical / supercritical CO2 (sCO2) recompression Brayton cycle using a novel rotary liquid piston compressor (LPC). This new type of multi-phase compressor utilizes a pumped motive fluid that interfaces with sCO2 in a rotating ducted cylinder for efficient CO2 compression at lower hardware costs. The energy required to pump the motive fluid can be significantly lower than that required to compress CO2 in a traditional compressor. The compressor utilizes a low compressibility, low diffusivity, low solubility liquid as the motive fluid to pressurize process fluid (sCO2) stream. Its use as a replacement for the main compressor in a recompression sCO2 Brayton cycle is expected to reduce compression power by more than 10% while maintaining robust operation over a wide range of ambient temperatures and CO2 densities that are typical for dry-cooled sCO2 cycles in arid climates. The new rotary liquid piston compressor also eliminates the need for gas lubricated bearings & dry gas seals, thus providing added advantage of rotordynamic stability, mechanical robustness & life over traditional compressors. Thermodynamic cycle analyses and 1D compressible flow analysis of multi-phase compression inside the rotary LPC is presented. An advanced 3D multi-phase flow model is developed to study fundamental physics of multi-species transport, diffusion & mixing of species and liquid-supercritical interface compression & decompression. This 3D model is used to validate some of the assumptions made in the 1D model. Various performance curves are developed to study the effect of lead flow, rotational speed and compressor inlet temperature on CO2 exit mass flow rate, % mixing of the two species, compression power requirements and overall compression efficiency. Optimization study on above system variables is carried out and a set of guidelines for use of rotary LPC in sCO2 compression is established.
{"title":"Transcritical / Supercritical CO2 Recompression Brayton Cycle Using a Novel Rotary Liquid Piston Compressor","authors":"A. Thatte","doi":"10.1115/gt2019-91088","DOIUrl":"https://doi.org/10.1115/gt2019-91088","url":null,"abstract":"This paper presents a transcritical / supercritical CO2 (sCO2) recompression Brayton cycle using a novel rotary liquid piston compressor (LPC). This new type of multi-phase compressor utilizes a pumped motive fluid that interfaces with sCO2 in a rotating ducted cylinder for efficient CO2 compression at lower hardware costs. The energy required to pump the motive fluid can be significantly lower than that required to compress CO2 in a traditional compressor. The compressor utilizes a low compressibility, low diffusivity, low solubility liquid as the motive fluid to pressurize process fluid (sCO2) stream. Its use as a replacement for the main compressor in a recompression sCO2 Brayton cycle is expected to reduce compression power by more than 10% while maintaining robust operation over a wide range of ambient temperatures and CO2 densities that are typical for dry-cooled sCO2 cycles in arid climates. The new rotary liquid piston compressor also eliminates the need for gas lubricated bearings & dry gas seals, thus providing added advantage of rotordynamic stability, mechanical robustness & life over traditional compressors. Thermodynamic cycle analyses and 1D compressible flow analysis of multi-phase compression inside the rotary LPC is presented. An advanced 3D multi-phase flow model is developed to study fundamental physics of multi-species transport, diffusion & mixing of species and liquid-supercritical interface compression & decompression. This 3D model is used to validate some of the assumptions made in the 1D model. Various performance curves are developed to study the effect of lead flow, rotational speed and compressor inlet temperature on CO2 exit mass flow rate, % mixing of the two species, compression power requirements and overall compression efficiency. Optimization study on above system variables is carried out and a set of guidelines for use of rotary LPC in sCO2 compression is established.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"67 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127450675","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}
Gas Transport System Operators (TSO1) are considering injecting hydrogen gas in their networks. Blending hydrogen into the existing natural gas pipeline network appears to be a strategy for storing and delivering renewable energy to markets [1], [2],[3]. In comparison to methane, hydrogen gas (dihydrogen or molecular hydrogen) has a higher mass calorific value than methane gas. Because of this property, molecular hydrogen is appreciated for space shuttle engines. A second property is that hydrogen gas has a lower mass density than methane gas. The result of the second property is that the volume calorific value is in favor of methane gas. The list of differences between methane and hydrogen is long. In the relevant range of pressures and temperatures, the Joule-Thomson coefficient has a different sign for hydrogen and methane, and the compressibility factor has the opposite trend when the gas is compressed. The dynamic viscosity is also significantly different, and finally, heat capacity, isentropic exponent, and the thermal conductivity are also different. What are the impacts of these hydrogen characteristics on the transport capacity and its efficiency in the case of blending in a gas transport network? The first part of the paper is a review of the differences in characteristics between Hydrogen Gas and a Typical Natural Gas in Europe and their impact on the gas flow performance in a pipeline network equipped with compressors. The second part of the paper is dedicated to pipe segments. And in the third part, compressor stations are introduced between each pipe segment. At each step, an analysis of a mixed gas from one hundred per cent pure natural gas to one hundred per cent pure hydrogen is done. The paper provides some results for 10 %, 40 %, and 100 % of hydrogen blending in an international pipeline. The study shows that the energy quantity transported at the same pressure ratio is reduced respectively by 4 %, 14 %, and 15 to 20 %, and energy requirement for compression increases respectively by 7 %, 30 %, and 210 % (i.e. it more than triples). To transport the same quantity of energy in a network, assuming the resizing to the same level of optimizations, the energy requirement increases by 11 %, 52 %, and 280 %. In other words, it takes 4 times the energy to transport a given amount of energy if the gas is pure hydrogen than it takes if the gas is pure natural gas. The paper does not address the issue of equipment or material, it only compares the influence of hydrogen gas on the network capacity and the transport efficiency. This paper doesn’t take into account the limits of the equipment. All equipment is considered as compatible with any load of hydrogen blending.
{"title":"Impacts of H2 Blending on Capacity and Efficiency on a Gas Transport Network","authors":"Francis Bainier, R. Kurz","doi":"10.1115/gt2019-90348","DOIUrl":"https://doi.org/10.1115/gt2019-90348","url":null,"abstract":"\u0000 Gas Transport System Operators (TSO1) are considering injecting hydrogen gas in their networks. Blending hydrogen into the existing natural gas pipeline network appears to be a strategy for storing and delivering renewable energy to markets [1], [2],[3].\u0000 In comparison to methane, hydrogen gas (dihydrogen or molecular hydrogen) has a higher mass calorific value than methane gas. Because of this property, molecular hydrogen is appreciated for space shuttle engines. A second property is that hydrogen gas has a lower mass density than methane gas. The result of the second property is that the volume calorific value is in favor of methane gas. The list of differences between methane and hydrogen is long. In the relevant range of pressures and temperatures, the Joule-Thomson coefficient has a different sign for hydrogen and methane, and the compressibility factor has the opposite trend when the gas is compressed. The dynamic viscosity is also significantly different, and finally, heat capacity, isentropic exponent, and the thermal conductivity are also different.\u0000 What are the impacts of these hydrogen characteristics on the transport capacity and its efficiency in the case of blending in a gas transport network?\u0000 The first part of the paper is a review of the differences in characteristics between Hydrogen Gas and a Typical Natural Gas in Europe and their impact on the gas flow performance in a pipeline network equipped with compressors.\u0000 The second part of the paper is dedicated to pipe segments. And in the third part, compressor stations are introduced between each pipe segment. At each step, an analysis of a mixed gas from one hundred per cent pure natural gas to one hundred per cent pure hydrogen is done.\u0000 The paper provides some results for 10 %, 40 %, and 100 % of hydrogen blending in an international pipeline. The study shows that the energy quantity transported at the same pressure ratio is reduced respectively by 4 %, 14 %, and 15 to 20 %, and energy requirement for compression increases respectively by 7 %, 30 %, and 210 % (i.e. it more than triples). To transport the same quantity of energy in a network, assuming the resizing to the same level of optimizations, the energy requirement increases by 11 %, 52 %, and 280 %. In other words, it takes 4 times the energy to transport a given amount of energy if the gas is pure hydrogen than it takes if the gas is pure natural gas.\u0000 The paper does not address the issue of equipment or material, it only compares the influence of hydrogen gas on the network capacity and the transport efficiency. This paper doesn’t take into account the limits of the equipment. All equipment is considered as compatible with any load of hydrogen blending.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133319081","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}
Haoxiang Chen, W. Zhuge, Yangjun Zhang, Hongdan Liu
Supercritical carbon dioxide (S-CO2) Brayton power cycle has attracted a lot of attention around the world in energy conversion field. It takes advantage of the high density of CO2 near the critical point while maintaining low viscosity to reduce compressor power and achieve high cycle efficiency. However, as CO2 approaches to its critical point, the thermodynamic properties of CO2 vary dramatically with small changes in temperature or pressure. As a result, the density of the working fluid varies significantly at the compressor inlet in the practical cycle if operating near the critical point, especially for small-scale cycles and air-cooled cycles, which leads to compressors operating out of the flow range, even being damaged. Concerns of large density variations at the inlet of the compressor result in S-CO2 compressor designers selecting compressor inlet conditions away from the critical point, thereby increasing compressor power. In this paper, a criterion to choose inlet pressure and inlet temperature of compressors as the design inlet condition is proposed, which is guaranteeing ±50% change in inlet specific volume within ±3 °C variation in inlet temperature. By the criterion, 8 MPa and 34.7 °C is selected as the design inlet condition. According to design requirements of the cycle, a S-CO2 centrifugal compressor is designed through 1-D design methodology. Based on the two-zone model, the effects of compressor inlet condition including inlet pressure and inlet temperature on the compressor performance are analyzed in detail. In practical operation, the compressor inlet condition is varied. Thus, an accurate prediction of compressor performance under different inlet conditions is necessary. The traditional correction method is not suitable for S-CO2 compressor. Dimensionless specific enthalpy rise is used to correct pressure ratio by the real gas table. And the S-CO2 compressor performance can be predicted correctly under different inlet conditions.
{"title":"Effect of Compressor Inlet Condition on Supercritical Carbon Dioxide Compressor Performance","authors":"Haoxiang Chen, W. Zhuge, Yangjun Zhang, Hongdan Liu","doi":"10.1115/gt2019-90647","DOIUrl":"https://doi.org/10.1115/gt2019-90647","url":null,"abstract":"\u0000 Supercritical carbon dioxide (S-CO2) Brayton power cycle has attracted a lot of attention around the world in energy conversion field. It takes advantage of the high density of CO2 near the critical point while maintaining low viscosity to reduce compressor power and achieve high cycle efficiency. However, as CO2 approaches to its critical point, the thermodynamic properties of CO2 vary dramatically with small changes in temperature or pressure. As a result, the density of the working fluid varies significantly at the compressor inlet in the practical cycle if operating near the critical point, especially for small-scale cycles and air-cooled cycles, which leads to compressors operating out of the flow range, even being damaged. Concerns of large density variations at the inlet of the compressor result in S-CO2 compressor designers selecting compressor inlet conditions away from the critical point, thereby increasing compressor power. In this paper, a criterion to choose inlet pressure and inlet temperature of compressors as the design inlet condition is proposed, which is guaranteeing ±50% change in inlet specific volume within ±3 °C variation in inlet temperature. By the criterion, 8 MPa and 34.7 °C is selected as the design inlet condition. According to design requirements of the cycle, a S-CO2 centrifugal compressor is designed through 1-D design methodology. Based on the two-zone model, the effects of compressor inlet condition including inlet pressure and inlet temperature on the compressor performance are analyzed in detail. In practical operation, the compressor inlet condition is varied. Thus, an accurate prediction of compressor performance under different inlet conditions is necessary. The traditional correction method is not suitable for S-CO2 compressor. Dimensionless specific enthalpy rise is used to correct pressure ratio by the real gas table. And the S-CO2 compressor performance can be predicted correctly under different inlet conditions.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124133351","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}
Levelised cost of energy is an important measure to evaluate the success of a wind energy project. It includes all the capital and operational expenditures of a wind turbine over its lifetime based on the expected power generated. In the literature, wind turbine reliability is largely neglected in levelised cost of energy estimation. This paper presents a model to evaluate levelised cost of energy while considering the reliability and maintenance of wind turbine subassemblies. The key concept behind this model is that the failure rate of a wind turbine subassembly depends on the preventive maintenance spending. The proposed model makes it possible to relate reliability data, such as failure rate and downtime of wind turbine subassemblies, to the operation and maintenance expenditure, as well as the annual energy production. The model is analysed using a sample set of recently published reliability data and it is observed that both the operation and maintenance expenditure and levelised cost of energy are convex functions of the subassembly’s failure rate and the preventive maintenance spending. This study can help wind turbine manufacturers and operators identify the level of reliability improvement and maintenance investment required to minimise the levelised cost of energy.
{"title":"Modelling the Effects of Reliability and Maintenance on Levelised Cost of Wind Energy","authors":"C. Dao, B. Kazemtabrizi, C. Crabtree","doi":"10.1115/gt2019-90015","DOIUrl":"https://doi.org/10.1115/gt2019-90015","url":null,"abstract":"\u0000 Levelised cost of energy is an important measure to evaluate the success of a wind energy project. It includes all the capital and operational expenditures of a wind turbine over its lifetime based on the expected power generated. In the literature, wind turbine reliability is largely neglected in levelised cost of energy estimation. This paper presents a model to evaluate levelised cost of energy while considering the reliability and maintenance of wind turbine subassemblies. The key concept behind this model is that the failure rate of a wind turbine subassembly depends on the preventive maintenance spending. The proposed model makes it possible to relate reliability data, such as failure rate and downtime of wind turbine subassemblies, to the operation and maintenance expenditure, as well as the annual energy production. The model is analysed using a sample set of recently published reliability data and it is observed that both the operation and maintenance expenditure and levelised cost of energy are convex functions of the subassembly’s failure rate and the preventive maintenance spending. This study can help wind turbine manufacturers and operators identify the level of reliability improvement and maintenance investment required to minimise the levelised cost of energy.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129994591","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}
M. A. Ancona, M. Bianchi, L. Branchini, F. Catena, A. D. Pascale, F. Melino, A. Peretto
In the last years, the increased demand of the energy market has led to the increasing penetration of renewable energies, in order to achieve the primary energy supply. Simultaneously, natural gas is predicted to play a vital and strategic role in the energy market, on account of its lower environmental impact than other fossil fuels, both as gaseous fuel for stationary energy generation and as liquefied fuel. In particular, the Liquefied Natural Gas (LNG) is becoming interesting in transports as an alternative to diesel fuel, allowing a decrease in pollutant emissions and a reduction in fuel’s costs for the users. As a consequence, in this context, the LNG production process can be seen as an electrical storage system by the integration with renewables, becoming an interesting solution to avoid the issues related to intermittency and unpredictability of renewables. The aim of the paper is the development of a calculation code and the evaluation of the off-design operation of a LNG production plant coupled with wind renewable energy sources. With this purpose, on the basis of mathematical models from literature, a dedicated calculation code has been developed, able to thermodynamically analyze both design and off-design operation of the integrated process. In addition, in this study the proposed model is employed to investigate the correct integration between renewables and LNG generation, in order to define the optimal choice of the wind size for a given LNG production plant. With this purpose, the LNG plant size of a real prototype has been considered and an economic analysis has been carried out, accounting for the revenue of the LNG sale, the costs for NG purchase, for operation and maintenance and for the initial investment costs, but also with the aim to minimize the electricity introduction into the grid, considered in this study as a penalty.
{"title":"Off-Design Performance Evaluation of a LNG Production Plant Coupled With Renewables","authors":"M. A. Ancona, M. Bianchi, L. Branchini, F. Catena, A. D. Pascale, F. Melino, A. Peretto","doi":"10.1115/gt2019-90495","DOIUrl":"https://doi.org/10.1115/gt2019-90495","url":null,"abstract":"\u0000 In the last years, the increased demand of the energy market has led to the increasing penetration of renewable energies, in order to achieve the primary energy supply. Simultaneously, natural gas is predicted to play a vital and strategic role in the energy market, on account of its lower environmental impact than other fossil fuels, both as gaseous fuel for stationary energy generation and as liquefied fuel. In particular, the Liquefied Natural Gas (LNG) is becoming interesting in transports as an alternative to diesel fuel, allowing a decrease in pollutant emissions and a reduction in fuel’s costs for the users. As a consequence, in this context, the LNG production process can be seen as an electrical storage system by the integration with renewables, becoming an interesting solution to avoid the issues related to intermittency and unpredictability of renewables.\u0000 The aim of the paper is the development of a calculation code and the evaluation of the off-design operation of a LNG production plant coupled with wind renewable energy sources. With this purpose, on the basis of mathematical models from literature, a dedicated calculation code has been developed, able to thermodynamically analyze both design and off-design operation of the integrated process. In addition, in this study the proposed model is employed to investigate the correct integration between renewables and LNG generation, in order to define the optimal choice of the wind size for a given LNG production plant. With this purpose, the LNG plant size of a real prototype has been considered and an economic analysis has been carried out, accounting for the revenue of the LNG sale, the costs for NG purchase, for operation and maintenance and for the initial investment costs, but also with the aim to minimize the electricity introduction into the grid, considered in this study as a penalty.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132718586","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}
An experimental facility is currently operating at Cranfield University in the UK and it is being used to explore supercritical carbon dioxide as a working fluid for future bottoming power cycle applications. The initial objective of this experimental programme is to de-risk and demonstrate the robustness of a closed-loop system, whilst proving the function and performance of individual components and various measurement and control modules. This paper describes the first operational experience gained whilst operating the test facility. More specifically, it summarizes the lessons learned from the commissioning phase and first test campaigns carried out in 2018.
{"title":"An Overview of Initial Operational Experience With the Closed-Loop sCO2 Test Facility at Cranfield University","authors":"Eduardo Anselmi, I. Bunce, V. Pachidis","doi":"10.1115/gt2019-91391","DOIUrl":"https://doi.org/10.1115/gt2019-91391","url":null,"abstract":"\u0000 An experimental facility is currently operating at Cranfield University in the UK and it is being used to explore supercritical carbon dioxide as a working fluid for future bottoming power cycle applications. The initial objective of this experimental programme is to de-risk and demonstrate the robustness of a closed-loop system, whilst proving the function and performance of individual components and various measurement and control modules. This paper describes the first operational experience gained whilst operating the test facility. More specifically, it summarizes the lessons learned from the commissioning phase and first test campaigns carried out in 2018.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115182572","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}
Liquefied Natural Gas (LNG) liquefaction plants have become increasingly important as natural gas is exported from the United States of America to markets world-wide. Downtime of any part of the process train (gas turbine, compressors, controls, etc.) due to failure of one or more of its components can result in high costs. The total cost of loss is of great concern to the LNG industry as it moves towards increased LNG exports with required operational efficiency, and downtime reduced to a minimum. This paper reports the application of a methodology of property risk assessment, providing insight into the use of PML (Probable Maximum Loss) and MFL (Maximum Foreseeable Loss) risk measures. Major sources of risk are analyzed, drawing from both technical literature and operational information on typical large LNG liquefaction plants. The outcome of this paper is an estimation of the economic loss associated with property risk for two hypothetical LNG liquefaction plants, based upon sample plants located in North America and characterized by different capacity. These plants represent recently built and commissioned plants and are chosen to take advantage of current technology and plant capacities.
{"title":"Property Risk Assessment for Liquefied Natural Gas Liquefaction Plants","authors":"G. Orme, M. Venturini","doi":"10.1115/gt2019-90068","DOIUrl":"https://doi.org/10.1115/gt2019-90068","url":null,"abstract":"Liquefied Natural Gas (LNG) liquefaction plants have become increasingly important as natural gas is exported from the United States of America to markets world-wide. Downtime of any part of the process train (gas turbine, compressors, controls, etc.) due to failure of one or more of its components can result in high costs. The total cost of loss is of great concern to the LNG industry as it moves towards increased LNG exports with required operational efficiency, and downtime reduced to a minimum.\u0000 This paper reports the application of a methodology of property risk assessment, providing insight into the use of PML (Probable Maximum Loss) and MFL (Maximum Foreseeable Loss) risk measures. Major sources of risk are analyzed, drawing from both technical literature and operational information on typical large LNG liquefaction plants.\u0000 The outcome of this paper is an estimation of the economic loss associated with property risk for two hypothetical LNG liquefaction plants, based upon sample plants located in North America and characterized by different capacity. These plants represent recently built and commissioned plants and are chosen to take advantage of current technology and plant capacities.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129964474","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}
Marco Mariottini, N. Pieroni, P. Bertini, Beniamino Pacifici, Alessandro Giorgetti
In the oil and gas industry, manufacturers are continuously engaged in providing machines with improved performance, reliability and availability. First Stage Bucket is one of the most critical gas turbine components, bearing the brunt of very severe operating conditions in terms of high temperature and stresses; aeromechanic behavior is a key characteristic to be checked, to assure the absence of resonances that can lead to damage. Aim of this paper is to introduce a method for aeromechanical verification applied to the new First Stage Bucket for heavy duty MS5002 gas turbine with integrated cover plates. This target is achieved through a significantly cheaper and streamlined test (a rotating test bench facility, formally Wheel Box Test) in place of a full engine test. Scope of Wheel Box Test is the aeromechanical characterization for both Baseline and New bucket, in addition to the validation of the analytical models developed. Wheel Box Test is focused on the acquisition and visualization of dynamic data, simulating different forcing frequencies, and the measurement of natural frequencies, compared with the expected results. Moreover, a Finite Elements Model (FEM) tuning for frequency prediction is performed. Finally, the characterization of different types of dampers in terms of impact on frequencies and damping effect is carried out. Therefore, in line with response assessment and damping levels estimation, the most suitable damper is selected. The proposed approach could be extended for other machine models and for mechanical audits.
{"title":"Wheel Box Test Aeromechanical Verification of New First Stage Bucket With Integrated Cover Plates for MS5002 GT","authors":"Marco Mariottini, N. Pieroni, P. Bertini, Beniamino Pacifici, Alessandro Giorgetti","doi":"10.1115/gt2019-90075","DOIUrl":"https://doi.org/10.1115/gt2019-90075","url":null,"abstract":"\u0000 In the oil and gas industry, manufacturers are continuously engaged in providing machines with improved performance, reliability and availability. First Stage Bucket is one of the most critical gas turbine components, bearing the brunt of very severe operating conditions in terms of high temperature and stresses; aeromechanic behavior is a key characteristic to be checked, to assure the absence of resonances that can lead to damage. Aim of this paper is to introduce a method for aeromechanical verification applied to the new First Stage Bucket for heavy duty MS5002 gas turbine with integrated cover plates. This target is achieved through a significantly cheaper and streamlined test (a rotating test bench facility, formally Wheel Box Test) in place of a full engine test. Scope of Wheel Box Test is the aeromechanical characterization for both Baseline and New bucket, in addition to the validation of the analytical models developed. Wheel Box Test is focused on the acquisition and visualization of dynamic data, simulating different forcing frequencies, and the measurement of natural frequencies, compared with the expected results. Moreover, a Finite Elements Model (FEM) tuning for frequency prediction is performed. Finally, the characterization of different types of dampers in terms of impact on frequencies and damping effect is carried out. Therefore, in line with response assessment and damping levels estimation, the most suitable damper is selected. The proposed approach could be extended for other machine models and for mechanical audits.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117011858","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}
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