Methane/coal dust/air explosions and their suppression by solid particle suppressing agents in a large-scale experimental tube

Ballast consisting of large sized aggregate particles with uniform size distribution is an essential component of the track substructure, to facilitate load distribution and drainage. As freight tonnage accumulates with traffic, ballast will accumulate an increasing percentage of fines due to either aggregate breakdown or outside contamination such as subgrade soil intrusion and coal dust collection. According to the classical text by Selig and Waters [1], ballast degradation from traffic involves up to 76% of all fouling cases; voids will be occupied by fines from the bottom of ballast layer gradually causing ballast clogging and losing its drainage ability. When moisture is trapped within ballast, especially fouled ballast, ballast layer stability is compromised. In the recent studies at the University of Illinois, the focus has been to evaluate behavior of fouled ballast due to aggregate degradation using large scale triaxial testing. To investigate the effects of moisture on degraded ballast, fouled ballast was generated in the laboratory through controlled Los Angeles (LA) abrasion tests intended to mimic aggregate abrasion and breakdown and generate fouled ballast at compositions similar to those observed in the field due to repeated train loadings. Triaxial shear strength tests were performed on the fouled ballast at different moisture contents. Important findings of this preliminary study on characterizing wet fouled ballast are presented in this paper. Moisture was found to have a significant effect on the fouled ballast strength behavior. Adding a small amount of 3% moisture (by weight of particles smaller than 3/8 in. size or smaller than 9.5 mm) caused test specimens to indicate approximately 50% decrease in shear strength of the dry fouled ballast. Wet fouled ballast samples peaked at significantly lower maximum deviator stress values at relatively smaller axial strains and remained at these low levels as the axial strain was increased.

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Central-Station Solar Hydrogen Power Plant

Solar Energy ◽

10.1115/isec2005-76052 ◽

2005 ◽

Author(s):

Gregory J. Kolb ◽

Richard B. Diver ◽

Nathan Siegel

Keyword(s):

Sulfuric Acid ◽

Solid Particle ◽

Large Scale ◽

Solar Power ◽

Storage System ◽

Energy Storage System ◽

Thermochemical Cycle ◽

Thermochemical Process ◽

Solar Power Tower ◽

Solar Electricity

Solar power towers can be used to make hydrogen on a large scale. Electrolyzers could be used to convert solar electricity produced by the power tower to hydrogen, but this process is relatively inefficient. Rather, efficiency can be much improved if solar heat is directly converted to hydrogen via a thermochemical process. In the research summarized here, the marriage of a high-temperature (∼1000 °C) power tower with a sulfuric acid/hybrid thermochemical cycle (SAHT) was studied. The concept combines a solar power tower, a solid-particle receiver, a particle thermal energy storage system, and a hybrid-sulfuric-acid cycle. The cycle is “hybrid” because it produces hydrogen with a combination of thermal input and an electrolyzer. This solar thermochemical plant is predicted to produce hydrogen at a much lower cost than a solar-electrolyzer plant of similar size. To date, only small lab-scale tests have been conducted to demonstrate the feasibility of a few of the subsystems and a key immediate issue is demonstration of flow stability within the solid-particle receiver. The paper describes the systems analysis that led to the favorable economic conclusions and discusses the future development path.

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Coal dust/air explosions in a large-scale tube

Fuel ◽

10.1016/j.fuel.2009.07.010 ◽

2010 ◽

Vol 89 (2) ◽

pp. 329-335 ◽

Cited By ~ 36

Author(s):

Qingming Liu ◽

Chunhua Bai ◽

Xiaodong Li ◽

Li Jiang ◽

Wenxi Dai

Keyword(s):

Large Scale ◽

Coal Dust

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Central-Station Solar Hydrogen Power Plant

Journal of Solar Energy Engineering ◽

10.1115/1.2710246 ◽

2006 ◽

Vol 129 (2) ◽

pp. 179-183 ◽

Cited By ~ 48

Author(s):

Gregory J. Kolb ◽

Richard B. Diver ◽

Nathan Siegel

Keyword(s):

Sulfuric Acid ◽

Solid Particle ◽

Large Scale ◽

Solar Power ◽

Storage System ◽

Energy Storage System ◽

Thermochemical Cycle ◽

Thermochemical Process ◽

Solar Power Tower ◽

Solar Electricity

Solar power towers can be used to make hydrogen on a large scale. Electrolyzers could be used to convert solar electricity produced by the power tower to hydrogen, but this process is relatively inefficient. Rather, efficiency can be much improved if solar heat is directly converted to hydrogen via a thermochemical process. In the research summarized here, the marriage of a high-temperature (∼1000°C) power tower with a sulfuric acid∕hybrid thermochemical cycle was studied. The concept combines a solar power tower, a solid-particle receiver, a particle thermal energy storage system, and a hybrid-sulfuric-acid cycle. The cycle is “hybrid” because it produces hydrogen with a combination of thermal input and an electrolyzer. This solar thermochemical plant is predicted to produce hydrogen at a much lower cost than a solar-electrolyzer plant of similar size. To date, only small lab-scale tests have been conducted to demonstrate the feasibility of a few of the subsystems and a key immediate issue is demonstration of flow stability within the solid-particle receiver. The paper describes the systems analysis that led to the favorable economic conclusions and discusses the future development path.

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Remote-Sensing Evaluation and Temporal and Spatial Change Detection of Ecological Environment Quality in Coal-Mining Areas

Remote Sensing ◽

10.3390/rs14020345 ◽

2022 ◽

Vol 14 (2) ◽

pp. 345

Author(s):

Xinran Nie ◽

Zhenqi Hu ◽

Mengying Ruan ◽

Qi Zhu ◽

Huang Sun

Keyword(s):

Coal Mining ◽

Coal Mine ◽

Large Scale ◽

Coal Dust ◽

Ecological Environment ◽

Ecological Index ◽

Mining Areas ◽

Environment Quality ◽

Temporal And Spatial

The large-scale development and utilization of coal resources have brought great challenges to the ecological environment of coal-mining areas. Therefore, this paper has used scientific and effective methods to monitor and evaluate whether changes in ecological environment quality in coal-mining areas are helpful to alleviate the contradiction between human and nature and realize the sustainable development of such coal-mining areas. Firstly, in order to quantify the degree of coal dust pollution in coal-mining areas, an index-based coal dust index (ICDI) is proposed. Secondly, based on the pressure-state-response (PSR) framework, a new coal-mine ecological index (CMEI) was established by using the principal component analysis (PCA) method. Finally, the coal-mine ecological index (CMEI) was used to evaluate and detect the temporal and spatial changes of the ecological environment quality of the Ningwu Coalfield from 1987 to 2021. The research shows that ICDI has a strong ability to extract coal dust with an overall accuracy of over 96% and a Kappa coefficient of over 0.9. As a normalized difference index, ICDI can better quantify the pollution degree of coal dust. The effectiveness of CMEI was evaluated by four methods: sample image-based, classification-based, correlation-based, and distance-based. From 1987 to 2021, the ecological environment quality of Ningwu Coalfield was improved, and the mean of CMEI increased by 0.1189. The percentages of improvement and degradation of ecological environment quality were 71.85% and 27.01%, respectively. The areas with obvious degradation were mainly concentrated in coal-mining areas and built-up areas. The ecological environment quality of Pingshuo Coal Mine, Shuonan Coal Mine, Xuangang Coal Mine, and Lanxian Coal Mine also showed improvement. The results of Moran’s Index show that CMEI has a strong positive spatial correlation, and its spatial distribution is clustered rather than random. Coal-mining areas and built-up areas showed low–low clustering (LL), while other areas showed high–high clustering (HH). The utilization and popularization of CMEI provides an important reference for decision makers to formulate ecological protection policies and implement regional coordinated development strategies.

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The Analysis of the Possibility of Feeding a Liquid Catalyst to a Coal Dust Channel

Energies ◽

10.3390/en14248521 ◽

2021 ◽

Vol 14 (24) ◽

pp. 8521

Author(s):

Zdzisław Bielecki ◽

Marek Ochowiak ◽

Sylwia Włodarczak ◽

Andżelika Krupińska ◽

Magdalena Matuszak ◽

...

Keyword(s):

Energy Consumption ◽

Experimental Research ◽

Lower Energy ◽

Power Plants ◽

Large Scale ◽

Coal Dust ◽

Exhaust Gases ◽

Flow Parameters ◽

Channel Outlet

This article presents the concept of a method of improving the dynamics of combustion in boilers operating in power plants, cogeneration plants, and heating plants by introducing a catalyst that is fed with a carrier in the form of droplets. Thanks to the proposed method, a greater degree of fuel burnout can be obtained, which, in turn, results in lower energy consumption in the case of producing the same amount of power. The parameters of the emitted exhaust gases and ash are also improved. The method described in the article involves the adding of a catalyst to the dust pipe of the boiler, which improves the combustion parameters. The catalyst was implemented using a sprayer/nebulizer. In order to obtain the correct flow parameters, the sprayer was modeled using CFD calculations. The calculations include trajectories, velocities and concentrations with regards to various flow parameters. Particular attention should be paid to the model of the evaporation of moving droplets. The results of these calculations enable the parameters that guarantee that the catalyst reaches the dust channel outlet in the desired form to be assessed. The analysis is an introduction to experimental research that is carried out on a medium and large scale.

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