Design and Optimization of a Pure Refrigerant Cycle for Natural Gas Liquefaction with Subcooling

Lee, Inkyu; Tak, Kyungjae; Kwon, Hweeung; Kim, Junghwan; Ko, Daeho; Moon, Il

doi:10.1021/ie403808y

Cited by 47 publications

(34 citation statements)

References 18 publications

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“…Wang et al [17] designed the C3MR process in Aspen Plus ® and presented an optimal design through Sequential Quadratic Programming (SQP). Hatcher et al [18], Lee et al [19], and Mortazavi et al [20] also modeled the C3MR process and subsequently optimized it via the Box method, Successive Reduced Quadratic Programming (SRQP), and hybrid optimization (i.e., Genetic Algorithm (GA) and SQP). Lee et al [21] applied multi-objective optimization (using SQP) via gProms process simulator to find an optimal design of SMR process.…”

Section: Introductionmentioning

confidence: 99%

Single-Solution-Based Vortex Search Strategy for Optimal Design of Offshore and Onshore Natural Gas Liquefaction Processes

et al. 2020

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Propane-Precooled Mixed Refrigerant (C3MR) and Single Mixed Refrigerant (SMR) processes are considered as optimal choices for onshore and offshore natural gas liquefaction, respectively. However, from thermodynamics point of view, these processes are still far away from their maximum achievable energy efficiency due to nonoptimal execution of the design variables. Therefore, Liquefied Natural Gas (LNG) production is considered as one of the energy-intensive cryogenic industries. In this context, this study examines a single-solution-based Vortex Search (VS) approach to find the optimal design variables corresponding to minimal energy consumption for LNG processes, i.e., C3MR and SMR. The LNG processes are simulated using Aspen Hysys and then linked with VS algorithm, which is coded in MATLAB. The results indicated that the SMR process is a potential process for offshore sites that can liquefy natural gas with 16.1% less energy consumption compared with the published base case. Whereas, for onshore LNG production, the energy consumption for the C3MR process is reduced up to 27.8% when compared with the previously published base case. The optimal designs of the SMR and C3MR processes are also found via distinctive well-established optimization approaches (i.e., genetic algorithm and particle swarm optimization) and their performance is compared with that of the VS methodology. The authors believe this work will greatly help the process engineers overcome the challenges relating to the energy efficiency of LNG industry, as well as other mixed refrigerant-based cryogenic processes.

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Section: Introductionmentioning

confidence: 99%

Single-Solution-Based Vortex Search Strategy for Optimal Design of Offshore and Onshore Natural Gas Liquefaction Processes

et al. 2020

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“…The natural gas liquefaction process is required because for long‐distance transport, its volume has to be reduced approximately 600 times . At atmospheric pressure, the natural gas boiling point is about −161°C .…”

Section: Introductionmentioning

confidence: 99%

“…The natural gas liquefaction process is required because for long-distance transport, its volume has to be reduced approximately 600 times. 31 At atmospheric pressure, the natural gas boiling point is about −161 C. 32 The processes for natural gas liquefaction are classified into three main types 30 : (a) cascade liquefaction, (b) MR liquefaction, and (c) expander-based liquefaction. A good number of researchers have investigated the optimum design and operating conditions in MR liquefaction process.…”

Section: Introductionmentioning

confidence: 99%

A novel integrated hydrogen and natural gas liquefaction process using two multistage mixed refrigerant refrigeration systems

2019

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Summary The development and analysis of combined hydrogen and natural gas liquefaction process are reported. Two refrigeration cycles using mixed refrigerants (MRs) are employed. The developed process is capable of generating 290 tons hydrogen and 296 tons liquid natural gas on daily basis. The first refrigeration cycle of the introduced process liquefies 3.5 kg·s−1 normal gaseous hydrogen and 3.5 kg·s−1 normal natural gas at room temperature and 21 bar to −195°C with the consumed power of 0.643 kWh/kgLH2,kgLNG. The second refrigeration cycle cools down the hydrogen and natural gas to −253°C with the consumed power of 1.662 kWh/kgLH2,kgLNG, leading to a lower total consumed power than that of the identical liquefaction processes. The use of novel and appropriately mixed refrigerants based on the configuration, and the thermal design of expanders and heat exchangers fora wide range of temperatures are the innovations of the process. Additionally, the refrigerant compositions of refrigeration cycles are novel. The energy analysis indicated that the coefficient of performance (COP) for the developed process is 0.2442, which is notably high compared with the COP of other identical processes (typically less than 0.1797). The exergy analysis revealed that the overall exergy efficiency of the liquefaction process is 62.54%. Highlight edited A novel integrated hydrogen and natural gas liquefaction process is introduced. The process can generate 290 tons hydrogen and 296 tons liquid natural gas per day. Total power consumptions of the process are 4.165 kWh/kgLH2,kgLNG. Coefficient of performance (COP) for the developed process is 0.2442, which is notably high compared with the COP of other identical processes. Overall exergy efficiency of the liquefaction process is 62.54%.

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“…Single mixed‐refrigerant processes have been subject to optimization in many studies, with varying values of the minimum temperature difference, such as 0.1 K, 1.2 K, 1.5 K, 2 K, 3 K, and 5 K . Similarly, the power consumption of propane‐precooled mixed‐refrigerant processes (C3MR) has been minimized requiring the minimum temperature difference to be larger than 2 K or 3 K. Alabdulkarem et al studied the influence of the minimum temperature difference on power consumption in a C3MR process by performing optimization with different values (0.01 K, 1 K, 3 K, and 5 K).…”

Section: Introductionmentioning

confidence: 99%

Impact of problem formulation on LNG process optimization

Austbø

Gundersen

2016

AIChE Journal

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The power consumption of a single mixed-refrigerant process (PRICO V R ) for natural gas liquefaction was minimized using four different constraint formulations to handle the trade-off between investment and operating costs. Aspen HYS-YS V R was used for process simulation, while a sequential quadratic programming algorithm (NLPQLP) was used for optimization. The results confirm that optimal utilization of the heat exchanger area is only obtained with a constraint based on a maximum heat exchanger conductance (UA). The minimum temperature difference constraint commonly used in process design gives a significant energy penalty as it is incapable of accounting for the distribution of driving forces with respect to temperature, the nonlinearity of the composite curves and the trade-off between driving forces and cooling load. The results also indicate that the maximum UA constraint leads to increased complexity of the optimization problem, and that the success rate of the optimization method used therefore is reduced. V C 2016 American Institute of Chemical Engineers AIChE J, 00: 000-000, 2016 Keywords: process optimization, heat transfer, driving forces, economic trade-off, liquefied natural gas IntroductionProcess design and operation is carried out with the prevailing objective of maximizing profit, or alternatively minimizing cost. Since detailed cost data seldom are available in an early design phase, a simplified approach is often taken. Both investment and operating costs are important for the overall economy of a plant, yet they are often in conflict. For many process units, improving operation comes at the expense of increased investment cost. Hence, to minimize the total cost of a process, the optimal trade-off between investment and operating costs must be found.For a heat-transfer process, both investment and operating costs are closely linked to the magnitude of the temperature driving forces. On one hand, the energy efficiency (and thereby the operating costs) is reduced when the driving forces are reduced. On the other hand, reduced driving forces lead to increased heat exchanger size (and thereby increased investment costs). To address this issue, a minimum temperature difference is commonly used as an economic trade-off parameter in heat exchanger network design. Jensen and Skogestad 1 found, however, that this approach gave suboptimal solutions when applied to design of processes for natural gas liquefaction, that is, subambient processes.Comparing different strategies for design of heat exchangers, Austbø and Gundersen 2 found that a design where the temperature difference in the heat exchanger is proportional to the temperature level, as suggested by Bejan, 3 Xu, 4 and Chang et al. 5 among others, gives the smallest irreversibilities associated with heat transfer. The potential savings in energy use, compared to a design with a uniform temperature difference throughout the heat-transfer process, were found to increase with decreasing temperature level and/or increasing temperature span. This sugg...

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Design and Optimization of a Pure Refrigerant Cycle for Natural Gas Liquefaction with Subcooling

Cited by 47 publications

References 18 publications

Single-Solution-Based Vortex Search Strategy for Optimal Design of Offshore and Onshore Natural Gas Liquefaction Processes

Single-Solution-Based Vortex Search Strategy for Optimal Design of Offshore and Onshore Natural Gas Liquefaction Processes

A novel integrated hydrogen and natural gas liquefaction process using two multistage mixed refrigerant refrigeration systems

Impact of problem formulation on LNG process optimization

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