Hydrofluoroolefin-based novel mixed refrigerant for energy efficient and ecological LNG production

Qyyum, Muhammad Abdul,Lee, Moonyong Elsevier 2018 ENERGY Vol.157 No.-

<P><B>Abstract</B></P> <P>To satisfy the worldwide demand for energy, the liquefied natural gas (LNG) industry has grown significantly in the past three decades owing to its low CO<SUB>2</SUB> emissions and high thermal efficiency compared to the other available energy resources. However, the process of natural gas liquefaction is generally considered to be energy-intensive. In this context, a novel hydrofluoroolefin (HFO-1234yf)-based mixed refrigerant, with the advantages of zero ozone depletion and minimal global warming potential, is proposed to liquefy natural gas in an ecological and energy-efficient manner. A new liquefaction cycle using the HFO-based mixed refrigerant is developed to fully utilize its potential. The results reveal that the overall energy requirement for natural gas liquefaction can be reduced by 46.4% compared with a single mixed refrigerant process, 42.5% compared with a dual mixed refrigerant process, and 36.3% compared with the Linde–single mixed refrigerant process. Economic analysis based on the capacity parameters of each equipment is also performed to emphasize the commercial feasibility of the proposed LNG process. The proposed HFO-based mixed refrigerant system provides an innovative solution to improve the ecological aspects and energy efficiency of natural gas liquefaction processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel 4th generation mixed refrigerant based on HFO-1234yf. </LI> <LI> An innovative refrigeration cycle for an energy efficient LNG production. </LI> <LI> The overall energy requirement for the LNG process is reduced significantly. </LI> <LI> Economic evaluation based on capacity parameters. </LI> </UL> </P>

An innovative vortex-tube turbo-expander refrigeration cycle for performance enhancement of nitrogen-based natural-gas liquefaction process

Qyyum, Muhammad Abdul,Wei, Feng,Hussain, Arif,Noon, Adnan Aslam,Lee, Moonyong Elsevier 2018 Applied thermal engineering Vol.144 No.-

<P><B>Abstract</B></P> <P>Liquefied natural gas (LNG) has attracted global attention as a more ecological energy source when compared to other fossil fuels. The nitrogen (N<SUB>2</SUB>) expander liquefaction is the most green and safe process among the different types of commercial natural gas liquefaction processes, but its relatively low energy efficiency is a major issue. To solve this issue, an energy-efficient, safe, and simple refrigeration cycle was proposed to improve the energy efficiency of the N<SUB>2</SUB> based natural-gas liquefaction process. In the proposed refrigeration cycle, vortex tube as an expansion device was integrated with turbo-expander in order to reduce the overall required energy for LNG production. A well-known commercial simulator Aspen Hysys® v9 was employed for modeling and analysis of proposed LNG process. The hybrid vortex-tube turbo-expander LNG process resulted in the specific energy requirement of 0.5900 kWh/kg LNG. Furthermore, the energy efficiency of the proposed LNG process was also compared with previous N<SUB>2</SUB> expander-based LNG processes. The results demonstrated that the proposed hybrid configuration saved up to 68.5% (depending on feed composition and conditions) in terms of the overall specific energy requirement in comparison with previous studies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An innovative vortex tube based N<SUB>2</SUB> expansion refrigeration cycle. </LI> <LI> Vortex tube is hybridized with turbo-expander for LNG production. </LI> <LI> The overall energy requirement for the LNG process is reduced significantly. </LI> <LI> The proposed refrigeration cycle can be implemented to other cryogenic processes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Energy efficiency enhancement of a single mixed refrigerant LNG process using a novel hydraulic turbine

Qyyum, Muhammad Abdul,Ali, Wahid,Long, Nguyen Van Duc,Khan, Mohd Shariq,Lee, Moonyong Elsevier 2018 ENERGY Vol.144 No.-

<P><B>Abstract</B></P> <P>The advancement in hydraulic turbine (HT) technology was exploited for energy and cost benefits in natural gas liquefaction. Replacing the conventional Joule–Thompson (JT) valve with HT has the potential to recover the work input. This research investigated the effect of replacing the JT valve with HT in the energy efficiency enhancement of a single mixed refrigerant (SMR) process. To fully take the potential benefit of the HT, the proposed SMR schemes were optimized by using a modified coordinate descent optimization method, which was implemented in Microsoft Visual Studio environment and linked to the rigorous HYSYS<SUP>®</SUP> model. The results showed that the required energy of the proposed HT based SMR process could be saved up to 16.5% in comparison with the conventional SMR process using the JT valves. Utilization of the recovered energy into boosting the natural gas feed pressure could further reduce the energy requirement up to 25.7%. Exergy efficiency analysis also showed that whole exergy efficiency of the enhanced SMR process can be increased by about 11% as compared to the base case. The proposed HT based liquefaction technology can be extended to other natural gas liquefaction processes as an attractive option for enhancing the energy efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An enhanced SMR process using hydraulic turbines was proposed for improving energy efficiency. </LI> <LI> Synergistic effects by hydraulic turbines with optimization were investigated. </LI> <LI> The proposed SMR process reduces energy requirement up to 16.5%. </LI> <LI> Efficient utilization of recovered energy further reduces energy requirement up to 25.7%. </LI> <LI> The proposed hydraulic turbine based liquefaction can be extended to other natural gas liquefaction processes. </LI> </UL> </P>

Design optimization of single mixed refrigerant LNG process using a hybrid modified coordinate descent algorithm

Qyyum, Muhammad Abdul,Long, Nguyen Van Duc,Minh, Le Quang,Lee, Moonyong Elsevier 2018 Cryogenics Vol.89 No.-

<P>Design optimization of the single mixed refrigerant (SMR) natural gas liquefaction (LNG) process involves highly non-linear interactions between decision variables, constraints, and the objective function. These non-linear interactions lead to an irreversibility, which deteriorates the energy efficiency of the LNG process. In this study, a simple and highly efficient hybrid modified coordinate descent (HMCD) algorithm was proposed to cope with the optimization of the natural gas liquefaction process. The single mixed refrigerant process was modeled in Aspen Hysys (R) and then connected to a Microsoft Visual Studio environment. The proposed optimization algorithm provided an improved result compared to the other existing methodologies to find the optimal condition of the complex mixed refrigerant natural gas liquefaction process. By applying the proposed optimization algorithm, the SMR process can be designed with the 0.2555 kW specific compression power which is equivalent to 44.3% energy saving as compared to the base case. Furthermore, in terms of coefficient of performance (COP), it can be enhanced up to 34.7% as compared to the base case. The proposed optimization algorithm provides a deep understanding of the optimization of the liquefaction process in both technical and numerical perspectives. In addition, the HMCD algorithm can be employed to any mixed refrigerant based liquefaction process in the natural gas industry.</P>

Coal to clean energy: Energy-efficient single-loop mixed-refrigerant-based schemes for the liquefaction of synthetic natural gas

Qyyum, Muhammad Abdul,Chaniago, Yus Donald,Ali, Wahid,Qadeer, Kinza,Lee, Moonyong Elsevier 2019 Journal of Cleaner Production Vol.211 No.-

<P><B>Abstract</B></P> <P>Higher air-pollutant (CO<SUB>2</SUB>, SO<SUB>2</SUB>, particulates, etc.) emission from coal burning prohibits the direct use of coal. The demand for clean and sustainable energy is increasing with the growth of population and living standards. Considering the current energy challenges, coal-enriched countries have focused on the green utilization of coal by converting it to a clean energy source, such as synthetic natural gas (SNG). To fulfill the global clean energy demand, liquefaction is a promising and feasible approach enabling safe storage and transportation. However, the liquefaction of SNG is an energy- and cost-intensive process, primarily owing to the presence of low-boiling impurities such as hydrogen and nitrogen. This paper describes the major challenges and issues associated with the SNG liquefaction process for its commercialization and attempts to solve the issues inherent to the SNG liquefaction industry. The optimal energy-efficient single-loop mixed-refrigerant-based liquefaction schemes, with the separation of low-boiling impurities (hydrogen and/or nitrogen), are presented as a major contribution of this study. The proposed SNG liquefaction schemes are analyzed in comparison with the latest SNG liquefaction study. Liquefied SNG can be produced with energy savings of up to 30.4% compared to the published base case.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Green utilization of coal to convert it to clean energy i.e., LNG. </LI> <LI> Synthetic natural gas liquefaction with the removal of low-boiling impurities. </LI> <LI> Single-loop mixed refrigerant for energy-efficient liquefaction. </LI> <LI> Hydrogen (H<SUB>2</SUB>) and nitrogen (N<SUB>2</SUB>) removal from synthetic natural gas. </LI> <LI> Flash, stripper, and distillation-based separation for H<SUB>2</SUB> and N<SUB>2</SUB> recovery. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Feasibility study of environmental relative humidity through the thermodynamic effects on the performance of natural gas liquefaction process

Qyyum, Muhammad Abdul,Minh, Le Quang,Ali, Wahid,Hussain, Arif,Bahadori, Alireza,Lee, Moonyong Elsevier 2018 Applied thermal engineering Vol.128 No.-

<P><B>Abstract</B></P> <P>This study examined the thermodynamic effects of relative humidity (RH) on the performance of the natural gas liquefaction process. A single mixed refrigerant (SMR) liquefaction process was chosen for this study because of its simplicity and compactness. In addition, it is considered the most promising process for the liquefied natural gas (LNG) floating production, storage and offloading (FPSO) unit. The SMR process was optimized using a modified coordinate descent methodology, which resulted in 13.6% energy savings. Subsequently, an interface between commercial software Aspen Hysys® and MS-Excel VBA was carried out to study the effects of RH. The results showed that RH has pronounced effects on the performance of the LNG cycle by affecting the enthalpy balance around the air coolers, which ultimately affects the overall compression power, LNG exchanger performance, and other design and operational parameters. Furthermore, when the RH was increased from 0% to 95%, the UA value (product of overall heat transfer coefficient and heat transfer area) of the air coolers and the overall compression power decreased and increased linearly, respectively. Moreover, the heat transfer coefficient of the LNG cryogenic exchanger increased asa 4th order polynomial function in terms of the log-mean enthalpy difference. The results can provide insight into the selection of the appropriate design and operational parameters for the LNG plants associated with the regions of low or high relative humidity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of relative humidity on the performance of SMR was investigated successfully. </LI> <LI> Compression energy for SMR process was reduced significantly. </LI> <LI> Compression power has a linear relation with the relative humidity. </LI> <LI> The UA value of LNG cryogenic exchanger increases as 4th-order polynomial function. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comprehensive Review of the Design Optimization of Natural Gas Liquefaction Processes: Current Status and Perspectives

Qyyum, Muhammad Abdul,Qadeer, Kinza,Lee, Moonyong American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.17

<P>Globally, liquefied natural gas (LNG) has drawn interest as a green energy source in comparison with other fossil fuels, mainly because of its ease of transport and low carbon dioxide emissions. However, LNG production is an energy and cost intensive process because of the huge power requirements for compression and refrigeration. Therefore, a major challenge in the LNG industry is to improve the energy efficiency of the LNG processes through economic and ecological strategies. Optimizing the design and operational parameters of the natural gas liquefaction cycles has been considered as one of most effective and popular approaches to address this issue. This paper reviews recent developments in the design optimization of LNG processes. In the choice of the most suitable and competitive LNG process, the operating costs, capital costs, environmental impact, and safety concerns must be considered for the optimal design and operation of LNG processes. The challenges in comparing recent researches are also discussed, along with suggestions for future directions to improve the energy efficiency of natural gas liquefaction processes.</P> [FIG OMISSION]</BR>

Nitrogen self-recuperation expansion-based process for offshore coproduction of liquefied natural gas, liquefied petroleum gas, and pentane plus

Qyyum, Muhammad Abdul,Qadeer, Kinza,Minh, Le Quang,Haider, Junaid,Lee, Moonyong Elsevier 2019 APPLIED ENERGY Vol.235 No.-

<P><B>Abstract</B></P> <P>In the current scenario of energy challenges, natural gas (NG) and associated liquids such as liquefied petroleum gas (LPG) are considered to be clean energy sources compared with coal and oil. Liquefaction is one of the most feasible and safe approaches for transporting NG from the site of production to the site of consumption. However, NG processing to produce liquefied natural gas (LNG) and LPG is extremely costly in terms of both operating and capital expenses because it requires a tremendous amount of energy, particularly at offshore sites. We have developed a new liquefaction process that uses N<SUB>2</SUB> self-recuperation rather than external precooling with 80% less energy consumption than that required by existing single N<SUB>2</SUB> expander processes. In this work, we evaluate the use of an innovative self-recuperative expander-based integrated process to produce LNG–LPG–pentane plus (condensate) at an offshore site in an energy-efficient manner with minimal capital expenditure. Thermodynamic and economic analyses were performed to evaluate the commercial feasibility of the proposed process. Furthermore, the environmental impact in terms of CO<SUB>2</SUB> emissions was calculated. This study reveals that LNG–LPG can be produced at a specific energy expense of 0.2362 kW with a payback period of 1.38 years.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An innovative self-recuperative expander-based integrated process. </LI> <LI> Offshore coproduction of LNG, LPG, and Pentane-plus. </LI> <LI> Commercial feasibility of integrated LNG-LPG-condensate production process. </LI> <LI> Energy and exergy analysis are performed. </LI> <LI> Environmental impact in terms of CO<SUB>2</SUB> emissions was also calculated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comprehensive Review of the Design Optimization of Natural Gas Liquefaction Processes: Current Status and Perspectives

Abdul Qyyum, Muhammad,Qadeer, Kinza,Lee, Moonyong ACS AMERICAN CHEMICAL SOCIETY 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.17

Krill-Herd-Based Investigation for Energy Saving Opportunities in Offshore Liquefied Natural Gas Processes

Qadeer, Kinza,Qyyum, Muhammad Abdul,Lee, Moonyong American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.42

<P>For offshore natural gas liquefaction operation, the single mixed refrigerant process is considered as one of the best and most suitable processes. However, multivariable nonlinear thermodynamic interactions among operating conditions and flow rates of mixed refrigerant ingredients lead to energy losses, which ultimately contributes to high energy consumption for liquefied natural gas production. The present work investigates the energy saving opportunities in the single mixed refrigerant liquefaction process through “krill-herd” strategy which is based on the biological flocking (herding) behavior of individual krill. To find the energy saving opportunities, the krill-herd approach effectively reduced the exergy losses of the compression units and cryogenic heat exchanger up to 18.6 and 41.1%, respectively, as compared to the published liquefaction process. The figure of merit was found as 27.0% in the krill-herd-optimized single mixed refrigerant process, whereas it was 22.2% in the base case.</P> [FIG OMISSION]</BR>