scholarly journals Artificial Intelligence Applied to Evaluate Emissions and Energy Consumption in Commuter Railways: Comparison of Liquefied Natural Gas as an Alternative Fuel to Diesel

2021 ◽  
Vol 13 (13) ◽  
pp. 7112
Author(s):  
Pablo Luque ◽  
Daniel A. Mántaras ◽  
Luciano Sanchez
Keyword(s):  
Energy Consumption ◽  
Diesel Engine ◽  
Natural Gas ◽  
Real Data ◽  
Liquefied Natural Gas ◽  
Transportation Sector ◽  
Railway Traction ◽  
Common Effort ◽  
The Impact ◽  
Pilot Tests

At present, there is a common effort to reduce the environmental effect of energy consumption. With this objective, the transportation sector seeks to improve emissions in all its modes. In particular, the rail transport industry is analysing various alternatives for non-electrified lines. These services are mainly carried out with diesel units. As an alternative to diesel fuel, in the present study the use of liquefied natural gas (LNG) in railway traction was analysed. A predictive model was developed and implemented in order to estimate the emissions impact of this fuel on different rail routes or networks. The model was fitted with real data obtained from pilot tests. In these tests, a train with two engines, one diesel and the other LNG, was used. The methodology was applied to evaluate the impact on consumption and emissions of the two fuels on a narrow-gauge commuter line. An improvement was observed in some indicators, while in others there was no clear progress. The conclusions that can be drawn are that CO2 (greenhouse gas) operating emissions are lower in the LNG engine than in the diesel line; CO emissions are lower in the diesel engine and emissions of other pollutants (nitrogen oxide and particles) are higher in the diesel engine by several orders of magnitude.

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 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.

Performance and emissions of an electronic control common-rail diesel engine fuelled with liquefied natural gas-diesel dual-fuel under an optimization control scheme

2018 ◽  
Vol 233 (6) ◽  
pp. 1380-1390 ◽  
Author(s):  
Jiantong Song ◽  
Chunhua Zhang ◽  
Guoqing Lin ◽  
Quanchang Zhang
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Fuel Consumption ◽  
Liquefied Natural Gas ◽  
Common Rail ◽  
Dual Fuel ◽  
Brake Specific Fuel Consumption ◽  
Electronic Control ◽  
Control Scheme ◽  
Optimization Control

In order to reduce the fuel consumption and hydrocarbon and CO emissions of liquefied natural gas-diesel dual-fuel engines under light loads, an optimization control scheme, in which the dual-fuel engine runs in original diesel mode under light loads, is used in this paper. The performance and exhaust emissions of the dual-fuel engine and the original diesel engine are compared and analyzed by bench tests of an electronic control common-rail diesel engine. Experimental results show that the brake-specific fuel consumption and hydrocarbon and CO emissions of the liquefied natural gas-diesel dual-fuel engine are not deteriorated under light loads. Compared with diesel, the brake power and torque of dual-fuel remain unchanged, the brake-specific fuel consumption decreases, and the smoke density and CO2 emissions of dual-fuel decrease, while the hydrocarbon and CO emissions increase, and there is no significant difference in NOx emissions.

Methane Emissions Reduction in Liquefied Natural Gas Off-Loading Process in Refueling Stations

2019 ◽  
Author(s):  
Amir Sharafian ◽  
Paul Blomerus ◽  
Walter Mérida
Keyword(s):  
Natural Gas ◽  
Greenhouse Gas ◽  
Methane Emissions ◽  
Liquefied Natural Gas ◽  
Process Time ◽  
Emissions Reduction ◽  
Pressure Buildup ◽  
Tanker Truck ◽  
Main Component ◽  
The Impact

Abstract Recent research into methane emissions from the liquefied natural gas (LNG) supply chain has revealed uncertainty in the overall greenhouse gas emissions reduction associated with the use of LNG in heavy-duty vehicles. Methane is the main component of natural gas and a potent greenhouse gas. This study investigates the impact of five methods used to offload LNG from a tanker truck to an LNG refueling station and estimate the amount of fugitive methane emissions. The LNG offloading process time, and the final pressures of the tanker truck and refueling station are considered to evaluate the performance of the LNG offloading methods. The modeling results show that the LNG transfer by using a pressure buildup unit has a limited operating range and can increase methane emissions by 10.4% of LNG offloaded from the tanker truck. The results indicate that the LNG transfer by using a pump and an auxiliary pressure buildup unit without vapor return provides the shortest fuel offloading time with the lowest risk of venting methane to the atmosphere.

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.

Impact of Railway Traction Energy Consumption on the Design Scheme

2012 ◽  
Vol 524-527 ◽  
pp. 3112-3117
Author(s):  
Fei Biao Bai ◽  
Hua Liu ◽  
Rong Hua Hou ◽  
Ge Fu Jiang
Keyword(s):  
Energy Consumption ◽  
Construction Projects ◽  
Scientific Basis ◽  
Total Energy Consumption ◽  
Railway Construction ◽  
Methods Of Calculation ◽  
Railway Industry ◽  
Railway Traction ◽  
The Impact ◽  
Energy Consumption Calculation

Facing the trend of energy crisis in the future, energy saving must start from aspects of the design. In China, the railway traction energy consumption is more than 80 per cent of energy consumption in the railway industry as a whole. First of all, this paper presents the energy consumption calculation of a single train, and analyzes the impact of energy consumption on the type of locomotive selection, then calculates total energy consumption and costs under the conditions of different ruling grades and route alternatives based on the life cycle of railway construction projects, which provides a scientific basis to determine the ruling grade and route alternatives. Finally, it illustrates an analysis of processes and methods of calculation through the Hainan West Ring Railway case.

scholarly journals Semi-analytical models of hydroelastic sloshing impact in tanks of liquefied natural gas vessels

2011 ◽  
Vol 369 (1947) ◽  
pp. 2920-2941 ◽  
Author(s):  
I. Ten ◽  
Š. Malenica ◽  
A. Korobkin
Keyword(s):  
Natural Gas ◽  
State Of The Art ◽  
Liquefied Natural Gas ◽  
Analytical Models ◽  
Structural Behaviour ◽  
Hydrodynamic Models ◽  
Basic Principles ◽  
Structural Part ◽  
The Impact ◽  
Violent Sloshing

The present paper deals with the methods for the evaluation of the hydroelastic interactions that appear during the violent sloshing impacts inside the tanks of liquefied natural gas carriers. The complexity of both the fluid flow and the structural behaviour (containment system and ship structure) does not allow for a fully consistent direct approach according to the present state of the art. Several simplifications are thus necessary in order to isolate the most dominant physical aspects and to treat them properly. In this paper, choice was made of semi-analytical modelling for the hydrodynamic part and finite-element modelling for the structural part. Depending on the impact type, different hydrodynamic models are proposed, and the basic principles of hydroelastic coupling are clearly described and validated with respect to the accuracy and convergence of the numerical results.

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