scholarly journals Natural Gas Variability In California: Environmental Impacts And Device Performance Combustion Modeling of Pollutant Emissions From a Residential Cooking Range

2011 ◽  
Author(s):  
S R Tonse ◽  
B C Singer
Keyword(s):  
Natural Gas ◽  
Environmental Impacts ◽  
Pollutant Emissions ◽  
Device Performance ◽  
Combustion Modeling

A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

2021 ◽  
pp. 146808742110050
Author(s):  
Enrica Malfi ◽  
Vincenzo De Bellis ◽  
Fabio Bozza ◽  
Alberto Cafari ◽  
Gennaro Caputo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Pollutant Emissions ◽  
Average Error ◽  
Combustion Engines ◽  
Nitric Oxides ◽  
Lean Burn ◽  
Fuel Charge ◽  
Unburned Hydrocarbons ◽  
Model Reliability

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

scholarly journals Assessing the Environmental Impact and Cost of the Tourism-Induced CO2, NOx, SOx Emission in China

2021 ◽  
Vol 13 (2) ◽  
pp. 604
Author(s):  
Yalan Shi ◽  
Miaojing Yu
Keyword(s):  
Environmental Impact ◽  
Environmental Impacts ◽  
Full Range ◽  
Correlation Effect ◽  
Tourism Industry ◽  
Pollutant Emissions ◽  
Travel Agency ◽  
Sustainable Mobility ◽  
Industrial Sectors ◽  
Direct Emission

Tourism, as one economic activity, results in a full range of environmental impacts globally as well as in China. However, the evaluation of environmental impacts is insufficient because of the strong correlation effect between tourism and other industries. This study attempted to assess the environmental impact and cost of the tourism-induced pollutant emissions (in a broad sense) at the national scale through constructing the environmental-economic input-output model. Our results suggested that the China’s total emission of CO2, NOx, SOx related to tourism industry increased from 42 × 106 t, 162 kt, 345 kt in 1995 to 157 × 106 t, 527 kt, 854 kt in 2009. The indirect CO2, NOx, and SOx emissions of tourism and related industries were nearly 6.8–11 times of their direct emission in travel agency. Most of these indirect emissions (73% of CO2 in 2009, 54% of NOx in 1995, 62% of SOx in 2009) are derived from the energy plants and industrial sectors. The sustainable tourism should largely depend on the realization of sustainable mobility and transportation, through the low-emission behavior and energy-saving technology. The emission reduction cost of tourism industry in China was 30,170 and 172,812 million CNY in 1995 and 2009, accounting for nearly 14% of the total tourism revenue.

scholarly journals CFD Study and Experimental Validation of a Dual Fuel Engine: Effect of Engine Speed

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4307
Author(s):  
Roberta De Robbio ◽  
Maria Cristina Cameretti ◽  
Ezio Mancaruso ◽  
Raffaele Tuccillo ◽  
Bianca Maria Vaglieco
Keyword(s):  
Natural Gas ◽  
High Performance ◽  
Engine Speed ◽  
Pollutant Emissions ◽  
Dual Fuel ◽  
Automotive Market ◽  
Light Duty ◽  
Viable Solution ◽  
Dual Fuel Engines ◽  
Gas Ratio

Dual fuel engines induce benefits in terms of pollutant emissions of PM and NOx together with carbon dioxide reduction and being powered by natural gas (mainly methane) characterized by a low C/H ratio. Therefore, using natural gas (NG) in diesel engines can be a viable solution to reevaluate this type of engine and to prevent its disappearance from the automotive market, as it is a well-established technology in both energy and transportation fields. It is characterized by high performance and reliability. Nevertheless, further improvements are needed in terms of the optimization of combustion development, a more efficient oxidation, and a more efficient exploitation of gaseous fuel energy. To this aim, in this work, a CFD numerical methodology is described to simulate the processes that characterize combustion in a light-duty diesel engine in dual fuel mode by analyzing the effects of the changes in engine speed on the interaction between fluid-dynamics and chemistry as well as when the diesel/natural gas ratio changes at constant injected diesel amount. With the aid of experimental data obtained at the engine test bench on an optically accessible research engine, models of a 3D code, i.e., KIVA-3V, were validated. The ability to view images of OH distribution inside the cylinder allowed us to better model the complex combustion phenomenon of two fuels with very different burning characteristics. The numerical results also defined the importance of this free radical that characterizes the areas with the greatest combustion activity.

Semi–Empirical Predictions and Correlations of NOx Emissions From Utility Combustion Turbines

1995 ◽  
Author(s):  
Donald M. Newburry ◽  
Arthur M. Mellor
Keyword(s):  
Natural Gas ◽  
A Priori ◽  
Fuel Oil ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Time Model ◽  
Heterogeneous Effects ◽  
Inlet Conditions ◽  
Thermal Nox ◽  
Semi Empirical

Semi–empirical equations model the dominant subprocesses involved in pollutant emissions by assigning specific times to the fuel evaporation, chemistry, and turbulent mixing. They then employ linear ratios of these times with model constants established by correlating data from combustors with different geometries, inlet conditions, fuels, and fuel injectors to make a priori predictions. In this work, thermal NOx emissions from two heavy–duty, dual fuel (natural gas and fuel oil #2) diffusion flame combustors designated A and B operating without inert injection are first predicted, and then correlated using three existing semi–empirical approaches termed the Lefebvre (AHL) model, the Rizk–Mongia (RM) model, and the characteristic time model (CTM). Heterogeneous effects were found to be significant, as fuel droplet evaporation times were required to align the natural gas and fuel oil data. Only the RM model and CTM were employed to study this phenomenon. The CTM achieved the best overall prediction and correlation, as the data from both combustors fell within one standard deviation of the predicted line. The AHL and RM models were not able to account for the geometries of the two combustors. For Combustor A the CTM parameter correlated the data in a highly linear manner, as expected, but for Combustor B there was significant curvature. Using the CTM this was shown to be a residence time effect.

Sustainability assessment of gas based power generation using a life cycle assessment approach

2018 ◽  
Vol 29 (5) ◽  
pp. 826-841 ◽  
Author(s):  
Binita Shah ◽  
Seema Unnikrishnan
Keyword(s):  
Power Generation ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Power Plant ◽  
Natural Gas ◽  
Environmental Impacts ◽  
Electricity Generation ◽  
Lca Methodology ◽  
Iso 14040 ◽  
Content Type

Purpose India is a developing economy along with an increasing population estimated to be the largest populated country in about seven years. Simultaneously, its power consumption is projected to increase more than double by 2020. Currently, the dependence on coal is relatively high, making it the largest global greenhouse gas emitting sector which is a matter of great concern. The purpose of this paper is to evaluate the environmental impacts of the natural gas electricity generation in India and propose a model using a life cycle assessment (LCA) approach. Design/methodology/approach LCA is used as a tool to evaluate the environmental impact of the natural gas combined cycle (NGCC) power plant, as it adopts a holistic approach towards the whole process. The LCA methodology used in this study follows the ISO 14040 and 14044 standards (ISO 14040: 2009; ISO 14044: 2009). A questionnaire was designed for data collection and validated by expert review primary data for the annual environmental emission was collected by personally visiting the power plant. The study follows a cradle to gate assessment using the CML (2001) methodology. Findings The analysis reveals that the main impacts were during the process of combustion. The Global warming potential is approximately 0.50 kg CO2 equivalents per kWh of electricity generation from this gas-based power plant. These results can be used by stakeholders, experts and members who are authorised to probe positive initiative for the reduction of environmental impacts from the power generation sector. Practical implications Considering the pace of growth of economic development of India, it is the need of the hour to emphasise on the patterns of sustainable energy generation which is an important subject to be addressed considering India’s ratification to the Paris Climate Change Agreement. This paper analyzes the environmental impacts of gas-based electricity generation. Originality/value Presenting this case study is an opportunity to get a glimpse of the challenges associated with gas-based electricity generation in India. It gives a direction and helps us to better understand the right spot which require efforts for the improvement of sustainable energy generation processes, by taking appropriate measures for emission reduction. This paper also proposes a model for gas-based electricity generation in India. It has been developed following an LCA approach. As far as we aware, this is the first study which proposes an LCA model for gas-based electricity generation in India. The model is developed in line with the LCA methodology and focusses on the impact categories specific for gas-based electricity generation.

scholarly journals Multi-Objective Optimization of a Regional Water–Energy–Food System Considering Environmental Constraints: A Case Study of Inner Mongolia, China

2020 ◽  
Vol 17 (18) ◽  
pp. 6834
Author(s):  
Junfei Chen ◽  
Tonghui Ding ◽  
Ming Li ◽  
Huimin Wang
Keyword(s):  
Natural Gas ◽  
Water Consumption ◽  
Inner Mongolia ◽  
Food System ◽  
Gas Production ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Basic Material ◽  
Multi Objective ◽  
Multi Objective Programming

Water, energy, and food, as the basic material resources of human production and life, play a prominent role in social and economic development. As the imbalance between the supply and demand of water, energy, and food increases, a highly sensitive and fragile relationship gradually forms among water, energy, and food. In this paper, Inner Mongolia in China is selected as a research area. Firstly, synergy theory is applied to establish the framework of a water–energy–food system. Then, a multi-objective programming model is constructed, where the objective functions are defined to minimize the integrated deviation degree and pollutant emissions of the water–energy–food system. Meanwhile, maximization of the water benefit, energy production, and food production is also considered. In addition, the model takes economy, environment, water, energy, and food as constraints. Finally, a genetic algorithm is designed for accurately assessing the most promising results. The results show that the cooperation degree of the water–energy–food system in Inner Mongolia is getting better and better, and the pollutant emission from the water–energy–food system is decreasing. In 2020, the proportion of agricultural water consumption fell by 1%, while that of industrial water consumption rose by 0.48%. The production of coal, natural gas, and power are all showing an increasing trend. Among them, the increase of natural gas production is as high as 38,947,730 tons of standard coal. However, the proportions of coal, natural gas, and power change inconsistently, where the proportions of coal and natural gas increase while that of power decreases. Corn production accounts for more than 80% of the total, which is in the eldest brother position in the food industry structure. Besides, there are differences between the planned values and optimal values of decision variables. Finally, suggestions are put forward to improve the sustainable development of water–energy–food in Inner Mongolia.

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