• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.261-265
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• 2022

In this paper, comparative studies between Linde, Claude and advanced cycle for the liquefaction of nitrogen have been completed. PRO/II with PROVISION release 2021. 1 from AVEVA company (Cambridge, UK) was used, and Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the condensation of nitrogen. When using Claude liquefaction, we can reduce the total compression power by 49.25% for the comparison of Linde cycle. And finally, we could conclude that 90.41% of total compression power was saved when using an advanced cycle being compared to Linde liquefaction cycle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.775-780
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• 2008

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.446-450
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• 2022

In this paper, comparative studies between Linde-Hampson and Claude cycle for the liquefaction of oxygen have been completed. PRO/II with PROVISION release 2021. 1 from AVEVA company (Cambridge, UK) was used, and Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the condensation of oxygen. When using Claude liquefaction cycle, we could reduce the total compression power by 59.51% for the comparison of Linde-Hampson cycle.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.4
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• pp.135-140
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• 2009

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.130-139
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• 1994

A cycle analysis was performed for 2-stage expansion Claude refrigerators by a numerical method. The refrigerators are under recent development such that the reciprocating expanders of Collins cycle are replaced by new turboexpanders. A computer simulation program was written to predict the coefficient of performance of the refrigerators for several input parameters. It was found out that there exist unique optimum values for the ratio of expanded mass through the turboexpanders to the total mass and for the intermediate pressure of the 2-stage expansion. The maximum coefficient of performance was about $5{\times}10^{-4}$ at the optimal operation.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.21-27
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• 2010

In the past vaporized gases from a carrier were burned or used for fuel. Due to the movement of bigger LNG carriers and using diesel engine, it is limited that ways of deposing vaporizes gases from the carrier by the act of environment. For getting over the problem, a reliquefaction process is considered. Even though the reliquefaction process was created to three generation process, it has been researched and developed to optimize the process. Basically the reliquefaction process is compartmentalized into Reverse Brayton Cycle System and Claude Cycle System. This research is focused on the reliquefaction efficiency with the systems and changing equipments arrangement by using HYSYS. The result could be use for a design of a reliquefaction process.

• Steel and Composite Structures
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• v.17 no.2
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• pp.185-198
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• 2014

Carbon-manganese steel A42 (French standards) is used in steam generator pipes of nuclear center and subject to low cycle fatigue (LCF) loads. In order to obtain the material LCF behavior, the tests are implemented in a hydraulic fatigue machine. The LCF plastic deformation and cyclic stress in macroscope have been influenced by the accumulated low cycle fatigue damage. The constitutive kinematic and isotropic hardening modeling is modified with coupling fatigue damage to describe the fatigue behavior. The improved model seems to be good agreement with the test results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.7
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• pp.485-490
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• 2007

The LNG BOG re-liquefaction system for LNG carriers was designed based on the Claude refrigeration cycle and the thermodynamic analysis was carried out in order to find the design point of the three heat exchangers constituting the system. The thermodynamic analysis revealed that the system state could be defined by the three cold endpoint temperatures of the three-pass heat exchanger. Hence the iso-lines of the specific liquefaction work, taken as the performance indicator, were presented in terms of those three temperatures and discussed. The system was found most economical when those three temperatures approached a single temperature of $-140^{\circ}C$ and thus this system state could be taken as the design point for the heat exchangers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.141-148
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• 2015

The cryogenic cooling system should maintain the HTS power cable below 77 K. As the length of HTS power cables has increased, there have been many efforts to develop large capacity cryocoolers. Brayton, Joule-Thomson, and Claude refrigerators were considered for the large capacity cryocooler. Among the various cryocoolers, the Brayton refrigerator is the most competitive in terms of the HTS power cable. At present, it is thought that a 10-kW class refrigerator will be able to be used as a unit cooling system for the commercialization of HTS power cables in the near future. The Brayton refrigerator is composed of recuperative heat exchangers, a compressor, and a cryogenic turbo expander. Among the various components, the cryogenic turbo expander is the part that decreases the temperature, and it is the most significant component that is closely related with overall system efficiency. It rotates at high speed using high-pressure helium or neon gas at cryogenic temperatures. This paper describes the design of a 300-W class Brayton refrigeration cycle and the cryogenic turbo expander as a downscale model for the practical 10-kW class cycle. Flow and structural analyses are performed on the rotating impeller and nozzle to verify the efficiency and the design performance.

• BMB Reports
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• v.38 no.1
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• pp.65-70
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• 2005

Choristoneura fumiferana granulovirus (ChfuGV) infection results two types of enveloped virions: Occlusion-derived virus (ODV) and budded virus (BV). Structural proteins ODVP-6E/ODV-E56 and p74 are two major conserved ODV-associated proteins that may be involved in the initiation of viral infection cycle in susceptible host insect larvae. This study presents the characterization of ChfuGV odvp-6e/odv-e56 and p74 transcription and translation as well as immunolocalization of these proteins in the occluded ChfuGV virion. Our results revealed that the transcription of odvp-6e/odv-e56 and p74 genes, both, start at 24 hours post infection (h p.i.). Using monospecific polyclonal antibodies made against ODVP-6E/ODV-E56 and p74 we demonstrated that these proteins are both expressed late in infection (24 h p.i.). Immunogold labeling using antisera against ODVP-6E/ODV-E56 and p74 proteins demonstrated that ODVP-6E/ODV-E56 and p74 proteins are both associated with the ODV envelop of ChfuGV.