scholarly journals Improved Configurations For Liquefied Natural Gas Cycles

2018 ◽  
Vol 1 (1) ◽  
pp. 19-37
Author(s):  
Said Al Rabadi
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Energy Savings ◽  
Liquefied Natural Gas ◽  
Considerable Reduction ◽  
Total Energy Consumption ◽  
Power Efficient ◽  
Natural Gas Liquefaction ◽  
Important Challenge ◽  
Reduction Of Energy Consumption

The most important challenge in a natural gas liquefaction plant is to improve the plant energy efficiency. A process topology should be implemented, which results in a considerable reduction of energy consumption as the natural gas liquefaction process consumes a large amount of energy. In particular, system design focusing on configuring cold part cycle is an attractive option. In this study, various energy recovery-oriented process configurations and the potential improvements of energy savings for small- & midscale liquefied natural gas plants were proposed and compared with almost exclusively commercial trademarks processes. These improved simulation based investigations were validated under the variation in feed gas pressure, mixed refrigerant cooling reference temperature and the pinch temperature of cryogenic plate fin heat exchanger. The simulation results exhibited considerable reduction of specific total energy consumption. Therefore, the proposed liquefaction cycles have a simple topology, hence lower capital cost and compacter plant layout, which is compatible for power-efficient, offshore, floating liquefied natural gas liquefaction plants.

scholarly journals Investigation on Energy Consumption of an Olympic Ice Rink and Sports Facility

2021 ◽  
Vol 65 (1) ◽  
pp. 113-118
Author(s):  
Hamdi Sunnetci ◽  
Deniz Yilmaz
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Total Energy ◽  
Co2 Emissions ◽  
Energy Savings ◽  
Cooling System ◽  
Electrical Energy ◽  
Total Energy Consumption ◽  
Energy Expenditures ◽  
The World

In these days, people spend 87% of their time indoors. Therefore, buildings are responsible for 36% of the total energy consumption and 40% of the CO2 emissions in the world. Besides, energy expenditures can be reduced, especially through improvements in public buildings used by many people. In this study, an annual energy consumption was conducted for an Olympic ice-skating rink and sports complex in Istanbul with a capacity of 900 spectators, was analyzed. Annual energy consumption of the building was 2 915 032 kWh electrical energy and 157 944 m3 natural gas. It was foreseen that 40 000kWh energy savings can be achieved annually with the evaporative pre-cooling system.

Energy savings potential of new aeration system: Full scale trials

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
A. Lazić ◽  
V. Larsson ◽  
Å. Nordenborg
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Total Energy ◽  
Energy Savings ◽  
Treatment Plant ◽  
Full Scale ◽  
Total Energy Consumption ◽  
Aeration System ◽  
Fine Bubble ◽  
Aeration Control

The objective of this work is to decrease energy consumption of the aeration system at a mid-size conventional wastewater treatment plant in the south of Sweden where aeration consumes 44% of the total energy consumption of the plant. By designing an energy optimised aeration system (with aeration grids, blowers, controlling valves) and then operating it with a new aeration control system (dissolved oxygen cascade control and most open valve logic) one can save energy. The concept has been tested in full scale by comparing two treatment lines: a reference line (consisting of old fine bubble tube diffusers, old lobe blowers, simple DO control) with a test line (consisting of new Sanitaire Silver Series Low Pressure fine bubble diffusers, a new screw blower and the Flygt aeration control system). Energy savings with the new aeration system measured as Aeration Efficiency was 65%. Furthermore, 13% of the total energy consumption of the whole plant, or 21 000 €/year, could be saved when the tested line was operated with the new aeration system.

scholarly journals A novel hybrid liquefied natural gas process with absorption refrigeration integrated with molten carbonate fuel cell

2021 ◽  
Author(s):  
Mehdi Mehrpooya ◽  
Parimah Bahramian ◽  
Fathollah Pourfayaz ◽  
Hadi Katooli ◽  
Mostafa Delpisheh
Keyword(s):  
Energy Consumption ◽  
Fuel Cell ◽  
Natural Gas ◽  
Hybrid System ◽  
Liquefied Natural Gas ◽  
Molten Carbonate Fuel Cell ◽  
Cooling Load ◽  
Absorption Refrigeration ◽  
Molten Carbonate ◽  
Carbonate Fuel Cell

Abstract The production of liquefied natural gas (LNG) is a high energy-consuming process. The study of ways to reduce energy consumption and consequently to reduce operational costs is imperative. Toward this purpose, this study proposes a hybrid system adopting a mixed refrigerant for the liquefaction of natural gas that is precooled with an ammonia/water absorption refrigeration (AR) cycle utilizing the exhaust heat of a molten carbonate fuel cell, 700°C and 2.74 bar, coupled with a gas turbine and a bottoming Brayton super-critical carbon dioxide cycle. The inauguration of the ammonia/water AR cycle to the LNG process increases the cooling load of the cycle by 10%, providing a 28.3-MW cooling load duty while having a 0.45 coefficient of performance. Employing the hybrid system reduces energy consumption, attaining 85% overall thermal efficiency, 53% electrical efficiency and 35% fuel cell efficiency. The hybrid system produces 6300 kg.mol.h−1 of LNG and 146.55 MW of electrical power. Thereafter, exergy and sensitivity analyses are implemented and, accordingly, the fuel cell had an 83% share of the exergy destruction and the whole system obtained a 95% exergy efficiency.

scholarly journals An energy-efficient metro speed profiles for energy savings: application to the Valencia metro

2016 ◽  
Author(s):  
Ignacio Villalba Sanchis ◽  
Pablo Salvador Zuriaga
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Economic Cost ◽  
Rolling Stock ◽  
Net Energy ◽  
General Terms ◽  
Proposed Model ◽  
Single Vehicle ◽  
Reduction Of Energy Consumption ◽  
Actual Energy Consumption

Nowadays one of the main priorities for metro line operators is the reduction of energy consumption, due to the environmental impact and economic cost. In order to achieve this objective different strategies can be applied, normally focused into rolling stock, infrastructure and/or operation. Considering short-term measures and related to the traffic operation strategies, different approaches are being researched. One of the most effective strategy which reduce net energy consumption is the use of efficient driving techniques. These techniques produces a speed profile between two stations that requires the minimum net energy consumption, without degrading commercial running times or passenger comfort. In this paper, a computer model for calculating the metro vehicles speed profiles minimizing the energy consumption was developed. The equations considered in the model represent the behavior of a single vehicle operated under manual driving, subject to different constraints such as the headway, cycle time, distances and acceleration limits. The proposed model calculates different commands to be systematically executed by the driver. The resulting simulator has been tuned by means of on board measurements of speed, accelerations and energy consumption obtained along different lines in Metro de Valencia network. For this purpose, different scenarios are analyzed to assess the achievable energy savings. In general terms and comparing with the actual energy consumption, the solutions proposed can reduce the net energy consumption around 19%.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3774

scholarly journals Modeling and Analysis of Coal-Based Lurgi Gasification for LNG and Methanol Coproduction Process

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 688 ◽  
Author(s):  
Gu ◽  
Yang ◽  
Kokossis
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Methanol Synthesis ◽  
Co2 Emission ◽  
Value Added ◽  
Economic Benefits ◽  
Liquefied Natural Gas ◽  
Utilization Efficiency ◽  
Separation Unit ◽  
Gas Removal

A coal-based coproduction process of liquefied natural gas (LNG) and methanol (CTLNG-M) is developed and key units are simulated in this paper. The goal is to find improvements of the low-earning coal to synthesis natural gas (CTSNG) process using the same raw material but producing a low-margin, single synthesis natural gas (SNG) product. In the CTLNG-M process, there are two innovative aspects. Firstly, the process can co-generate high value-added products of LNG and methanol, in which CH4 is separated from the syngas to obtain liquefied natural gas (LNG) through a cryogenic separation unit, while the remaining lean-methane syngas is then used for methanol synthesis. Secondly, CO2 separated from the acid gas removal unit is partially reused for methanol synthesis reaction, which consequently increases the carbon element utilization efficiency and reduces the CO2 emission. In this paper, the process is designed with the output products of 642,000 tons/a LNG and 1,367,800 tons/a methanol. The simulation results show that the CTLNG-M process can obtain a carbon utilization efficiency of 39.6%, bringing about a reduction of CO2 emission by 130,000 tons/a compared to the CTSNG process. However, the energy consumption of the new process is increased by 9.3% after detailed analysis of energy consumption. The results indicate that although electricity consumption is higher than that of the conventional CTSNG process, the new CTLNG-M process is still economically feasible. In terms of the economic benefits, the investment is remarkably decreased by 17.8% and an increase in internal rate of return (IRR) by 6% is also achieved, contrasting to the standalone CTSNG process. It is; therefore, considered as a feasible scheme for the efficient utilization of coal by Lurgi gasification technology and production planning for existing CTSNG plants.

scholarly journals Lighting Control Including Daylight and Energy Efficiency Improvements Analysis

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2166 ◽  
Author(s):  
Aniela Kaminska ◽  
Andrzej Ożadowicz
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Experimental Tests ◽  
Experimental Results ◽  
Automation System ◽  
Building Automation ◽  
Total Energy Consumption ◽  
Lighting Control

Energy used for lighting is one of the major components of total energy consumption in buildings. Nowadays, buildings have a great potential to reduce their energy consumption, but to achieve this purpose additional efforts are indispensable. In this study, the need for energy savings evaluation before the implementation of lighting control algorithms for a specified building is highlighted. Therefore, experimental tests have been carried out in a university building with laboratories and other rooms, equipped with KNX building automation system. A dimmable control strategy has been investigated, dependent on daylight illuminance. Moreover, a relationship between external and internal daylight illuminance levels has been evaluated as well. Based on the experimental results, the authors proposed a method for the rough estimation of electrical energy savings. Since, according to the EN 15232 standard, Building Automation and Control Systems (BACS) play an important role in buildings’ energy efficiency improvements, the BACS efficiency factors from this standard have been used to verify the experimental results presented in the paper. The potential to reduce energy consumption from lighting in non-residential buildings by 28% for offices and 24% for educational buildings has been confirmed, but its dependence on specific building parameters has been discussed as well.

scholarly journals Systematic Simplified Simulation Methodology for Deep Energy Retrofitting Towards Nze Targets Using Life Cycle Energy Assessment

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3038 ◽  
Author(s):  
José Sánchez Ramos ◽  
MCarmen Guerrero Delgado ◽  
Servando Álvarez Domínguez ◽  
José Luis Molina Félix ◽  
Francisco José Sánchez de la Flor ◽  
...  
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Building ◽  
Energy Performance ◽  
Simulation Tools ◽  
Energy Assessment ◽  
Energy Efficiency Improvement ◽  
The Difference ◽  
Reduction Of Energy Consumption

The reduction of energy consumption in the residential sector presents substantial potential through the implementation of energy efficiency improvement measures. Current trends involve the use of simulation tools which obtain the buildings’ energy performance to support the development of possible solutions to help reduce energy consumption. However, simulation tools demand considerable amounts of data regarding the buildings’ geometry, construction, and frequency of use. Additionally, the measured values tend to be different from the estimated values obtained with the use of energy simulation programs, an issue known as the ‘performance gap’. The proposed methodology provides a solution for both of the aforementioned problems, since the amount of data needed is considerably reduced and the results are calibrated using measured values. This new approach allows to find an optimal retrofitting project by life cycle energy assessment, in terms of cost and energy savings, for individual buildings as well as several blocks of buildings. Furthermore, the potential for implementation of the methodology is proven by obtaining a comprehensive energy rehabilitation plan for a residential building. The developed methodology provides highly accurate estimates of energy savings, directly linked to the buildings’ real energy needs, reducing the difference between the consumption measured and the predictions.

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

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1732 ◽  
Author(s):  
Muhammad Abdul Qyyum ◽  
Muhammad Yasin ◽  
Alam Nawaz ◽  
Tianbiao He ◽  
Wahid Ali ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Optimal Design ◽  
Natural Gas ◽  
Point Of View ◽  
Base Case ◽  
Aspen Hysys ◽  
Design Variables ◽  
Single Solution ◽  
Natural Gas Liquefaction

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.

scholarly journals Non-Renewable Energy and Macroeconomic Efficiency of Seven Major Oil Producing Economies in Africa

2016 ◽  
Vol 19 (1) ◽  
pp. 59-74 ◽  
Author(s):  
Olabanji Benjamin Awodumi ◽  
Adebowale Musefiu Adeleke
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Total Energy ◽  
Technical Efficiency ◽  
Fossil Fuel ◽  
Primary Energy ◽  
African Countries ◽  
Total Energy Consumption ◽  
Macroeconomic Efficiency ◽  
The Impact

Abstract This study adopted two-stage DEA to estimate the technical efficiency scores and assess the impact of the two most important components of fossil fuel associated with oil production on macroeconomic efficiency of Seven oil producing African countries during 2005-2012. Our results showed that increasing the consumption of natural gas would improve technical efficiency. Furthermore, increasing the share of fossil fuel in total energy consumption has negative effect on the efficiency of the economies of the top African oil producers. Also, we found that increasing the consumption of primary energy improves efficiency in these economies. We therefore, recommend that governments and other stakeholders in the energy industry should adopt inclusive strategies that will promote the use of natural gas in the short term. However, in the long-run, efforts should be geared towards increasing the use of primary energy, thereby reducing the percentage share of fossil fuel in total energy consumption.

scholarly journals The Strategy of Implementing Energy Efficiency Standards and Labels for Domestic Air Conditioners in Libya

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Salah M Alabani ◽  
Ibrahim H Tawil
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Total Energy Consumption ◽  
Air Conditioners ◽  
Improve Energy Efficiency ◽  
Reduce Energy Consumption ◽  
Two Stages ◽  
Energy Efficiency Standards

The residential sector in Libya has grown over the past decade in the construction of residential buildings due to the increase in the population. Moreover, the increase in the level of income has contributed to the increase in the purchase of household appliances, which leads to increased demand for energy. Energy consumption in the household sector accounted for 31% of total energy consumption during 2010, and the share of air conditioners in this sector consumed 18.35%. To reduce energy consumption and improve energy efficiency in this sector, policies should be considered to apply energy efficiency standards and markers to household electrical appliances, as they are considered one of the most successful programs used in the world. Countries are implementing such programs to reduce energy consumption in the domestic sector. This paper presents the possibility of implementing such programs to introduce the importance of energy efficiency standards and labeling programs for home appliances in Libya. The calculations required to design such programs show the energy savings that can be achieved during cooling loads in the summer period of 4 months July, August, September). A strategic plan has been developed during 10-year (2020-2030) to estimate the expected savings of energy consumed and to identify possible obstacles and difficulties by gradually increasing the energy efficiency ratio for comestic air conditioners in two stages, from EER10 to EER11 in the first stage is then raised to EER12 as the second stage.

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