Thermal Performance of Ammonia in Dual Mixed Refrigerant Cycle of Natural Gas Liquefaction Process

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Ray Soujoudi ◽  
Randall Manteufel
Keyword(s):  
Natural Gas ◽  
Methane Concentration ◽  
Exergy Efficiency ◽  
Feed Pressure ◽  
Operation Conditions ◽  
Through Flow ◽  
Unique Approach ◽  
Composite Curve ◽  
Liquefaction Process ◽  
Liquid Natural Gas

Abstract Mixed refrigerant (MR) system is commonly used for a liquefaction process of liquid natural gas (LNG) plants due to its higher efficiency of heat transfer rate compared to pure refrigerants. The performance of MR system is highly dependent on the variable refrigerant composition, which is challenging to obtain in a practical LNG plant setting. To address this challenge, this study investigates a unique approach to improve the exergy efficiency of liquefaction cycle employing ammonia in the mixture while keeping the MR molar composition constant in dual mixed refrigerant (DMR) cycle. A control strategy is proposed to regulate the MR flowrate through flow control sensors and a series of Joule-Thomason (JT) valves to sustain the desired efficiency of the cycle under various plant’s operation conditions. The robustness and adaptability of two proposed MR compositions were examined under eight cases by varying natural gas (NG) feed pressure and methane concentration. Composite curve plots were utilized as a tool to control the minimum temperature approach (MTA) and to improve exergy efficiency of the cycle. Furthermore, findings revealed that mixtures which included ammonia yielded a reduction in the number of compressors, as well as a reduced the overall amount of compressors rate of shaft work required for the liquefaction cycle. The results emphasize that DMR is most efficient when NG methane concentration is at 75%. Furthermore, the compressor rate of shaft work reduced by 13.3%, while exergy efficiency of the cycle increased by 14.3%, when natural gas methane concentration reduced from 90% to 75%.

Analysis and Optimization of Small Expansion Natural Gas Liquefaction Process

2014 ◽  
Vol 962-965 ◽  
pp. 473-478
Author(s):  
Yuan Wei Lu ◽  
Li Hua Liu ◽  
Yu Ting Wu ◽  
Chong Fang Ma ◽  
Jing Fu Wang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Power Consumption ◽  
Optimal Operation ◽  
Specific Power ◽  
Small Scale ◽  
Specific Power Consumption ◽  
Technical Parameters ◽  
Operation Conditions ◽  
Natural Gas Liquefaction ◽  
Liquefaction Process

In order to develop small-scale natural gas liquefaction equipment, a small expansion natural gas liquefaction process was designed, which was based on the technical parameters of the single screw compressor and expander developed by Beijing University of Technology. The effect of the key parameters on the natural gas liquefaction rate and specific power consumption was simulated and optimized. The results showed that the liquefaction rate of the process can reach 100% and the specific power consumption was relatively low under the optimal operation conditions. These research results can provide theoretical basis for the design of small-scale natural gas liquefaction equipment.

Blast-resistant buildings for Australia's North-West shelf liquid natural gas plant

1990 ◽  
Vol 9 (1-4) ◽  
pp. 175-197
Author(s):  
C. Turnell ◽  
N.W. Murray ◽  
I.D. Bennetts
Keyword(s):  
Natural Gas ◽  
North West ◽  
Liquid Natural Gas

The Lay-Up and Reactivation of LNG Tankers: Lessons Learned

1994 ◽  
Vol 10 (03) ◽  
pp. 174-183
Author(s):  
John W. Boylston ◽  
Paul J. Riley ◽  
Gary W. Van Tassel
Keyword(s):  
Natural Gas ◽  
Capital Cost ◽  
Lessons Learned ◽  
Inert Gas ◽  
Ballast Tank ◽  
Economic Decisions ◽  
Liquid Natural Gas ◽  
Gas Plants

The Liquid natural gas (LNG) industry went from a projected boom in the 1970's to a contracted industry in the 1980's, when many ships were either permanently or temporarily laid up. In the 1990s, many laid-up LNG carriers are being reactivated after as many as 12 years in lay-up. While the capital cost of an LNG carrier should dictate maximum preservation of the asset, the LNG industry is not immune to having to make hard economic decisions during slack times. In this paper, the authors present specific alternate lay-up procedures, together with the relative costs of these alternatives. LNG carriers are steam vessels, as are many of the vessels in the Ready Reserve Fleet (RRF). However, many of the conclusions reached can also be applied to motor vessels, and as such could be of interest to operators and shipyards in all phases of the RRF program. The subjects of dehumidification, inert gas plants, ballast tank coatings and drydocking, among others, are discussed.

scholarly journals Energetic and exergetic analyses of carbon dioxide transcritical refrigeration systems for hot climates

2015 ◽  
Vol 19 (3) ◽  
pp. 905-914 ◽  
Author(s):  
Farivar Fazelpour
Keyword(s):  
Carbon Dioxide ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Exergy Efficiency ◽  
Refrigeration System ◽  
Long Period ◽  
Operation Conditions ◽  
Scientific Papers ◽  
System Operating

In the last two decades many scientific papers and reports have been published in the field of the application of the carbon dioxide as a refrigerant for refrigeration systems and heat pumps. Special attention has been paid to the transcritical cycle. However, almost no papers discussed such cycles for hot climates, i.e., when the temperature of the environment is higher than 40?? during a long period of time. This paper deals with the energetic and exergetic evaluation of a CO2 refrigeration system operating in a transcritical cycle under hot climatic conditions. The performance and exergy efficiency of the CO2 refrigeration system depend on the operation conditions. The effect of varying these conditions is also investigated as well as the limitations associated with these conditions.

scholarly journals The Development of a Low-Cost Method for Monitoring Methane Leakage from the Subsurface of Natural Gas Fields

Methane ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 24-37
Author(s):  
Muhammad Alfiza Farhan ◽  
Yuichi Sugai ◽  
Nuhindro Priagung Widodo ◽  
Syafrizal Syafrizal
Keyword(s):  
Activated Carbon ◽  
Natural Gas ◽  
Methane Concentration ◽  
Low Cost ◽  
Gas Field ◽  
Methane Leakage ◽  
Wide Scale ◽  
Adsorbed Methane ◽  
In The Beginning ◽  
Gas Fields

The leakage of methane from the subsurface on the coalfield or natural gas field invariably becomes an important issue nowadays. In notable addition, materials such as activated carbon, zeolites, and Porapak have been successfully identified as adsorbents. Those adsorbents could adsorb methane at atmospheric pressure and room temperature. Therefore, in this scholarly study, a new method using adsorbents to detect points of methane leakage that can cover a wide-scale area was developed. In the beginning, the most capable adsorbent should be determined by quantifying adsorbed methane amount. Furthermore, checking the possibility of adsorption in the column diffusion and desorption method of adsorbents is equally necessary. The most capable adsorbent was activated carbon (AC), which can adsorb 1.187 × 10−3 mg-CH4/g-AC. Hereinafter, activated carbon successfully can adsorb methane through column diffusion, which simulates the situation of on-site measurement. The specific amount of adsorbed methane when the initial concentrations of CH4 in a bag were 200 ppm, 100 ppm, and 50 ppm was found to be 0.818 × 10−3 mg-CH4/g-AC, 0.397 × 10−3 mg-CH4/g-AC, 0.161 × 10−3 mg-CH4/g-AC, respectively. Desorption of activated carbon analysis shows that methane concentration increases during an hour in the temperature bath under 80 °C. In conclusion, soil methane leakage points can be detected using activated carbon by identifying the observed methane concentration increase.

scholarly journals Bezpieczeństwo dostaw surowców energetycznych do Polski drogą morską

2020 ◽  
Vol 14 ◽  
pp. 177-195
Author(s):  
Michał Piekarski
Keyword(s):  
Law Enforcement ◽  
Natural Gas ◽  
North Sea ◽  
Energy Sources ◽  
Liquid Natural Gas

Security of energy supplies to Poland by sea The article describes issue of security of delivery of energy sources – Liquid Natural Gas (LNG) and oil to Poland by the maritime routes. Poland currently uses one LNG terminal and one major oil import terminal, and further developments – Baltic Pipe pipeline from North Sea and another LNG terminal are planned. Security of those routes depends on various factors from security of terminals, safe passage of tankers and required using multiple elements, including security and law enforcement services, naval forces and air defence systems to provide reliable delivery of oil and LNG in case of peace, crisis and war.

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