Coal Mine Ventilation Research Articles

Experimental demonstration and modeling of an adsorption-enhanced reverse flow reactor for the catalytic combustion of coal mine ventilation air methane

Ventilation air methane is a major contributor to the carbon footprint of the coal mining industry. This contribution can be mitigated by combustion of methane to carbon dioxide. The use of efficient combustion devices, such as catalytic reverse flow reactors, can improve the economy of the process. However, the high water content of the ventilation air can inhibit catalysts (such as palladium) used in this process. The overcome this issue a novel reverse flow reactor with integrated separation, capable of adsorbing water from the feed before reaching the catalyst, is studied. The adsorbent is regenerated in situ thanks to the characteristic thermal pattern of reverse flow reactors. The application of this reactor design to the combustion of ventilation air methane has been demonstrated in a bench-scale device, operated at 0.15m/s (n.t.p.) superficial velocity and different methane concentrations (1800–5400ppm) and switching times (100–600s). A mathematical model for this reactor has been proposed, the water adsorption parameters have been determined experimentally, and the model has been validated by comparison to bench-scale experimental results.

Influence of packed honeycomb ceramic on heat extraction rate of packed bed embedded heat exchanger and heat transfer modes in heat transfer process

Under the condition that the transient oxidation heat extraction process of coal mine ventilation air methane (VAM) is equivalent to a series of steady state process, the steady state heat extraction experiment platform is built. The influence of the honeycomb ceramic packed in heat extraction zone and its two-side space on heat extraction rate and heat transfer modes is investigated. The experimental results show that the honeycomb ceramic packed in heat extraction zone two-side space can always strengthen heat extract ion of heat exchanger by increasing gas physical flow velocity in bed and radiation heat exchanging area and disturbing heat exchanger leeward side flow field. The contradictory dual characteristic of the influence of the honeycomb ceramic packed in heat extraction zone on heat exchanger heat extraction rate determines that the honeycomb ceramic has no great influence on heat extraction rate and doesn't always strengthen heat exchanger heat extraction. Contribution of heat transfer modes on packed bed embedded heat exchanger heat extraction is investigated using the method of coating heat exchanger outer surface silver; the experimental result shows that 55% contribution of packed bed embedded heat exchanger heat extraction rate is from radiation when gas mass flow rate is 0.15kg·s−1·m−2 and its temperature is 1113k; with the gas temperature being increased further, radiation will become the main way of packed bed embedded heat exchanger heat extraction.

Research on Index for Assessment of Mine Ventilation Capability

In order to perfect the current index equivalent orifice for assessment of coal mine ventilation capability checking, we put forward a new evaluation methodology to accomplish this aim based on existing research and the present practical conditions in China. In addition, indexes for calculating reasonable values of equivalent orifice for all kinds of mine ventilation systems are given. The new way is more reasonable and scientific by example. Equivalent orifice equation is analyzed and then it can be found that for the mines with different ventilation systems the calculation methods of total equivalent orifice and total windage are different. Equivalent orifice calculation needs the total amount of the return air in the mine; total windage is calculated according to the specific form of ventilation.

Use meteotron I for coal mine ventilation

The meteotron characteristics with thermal power of 0.24 million kilowatts and experimental conditions on an open coal mine ventilation heat method are shown. Heat and mass transfer mechanisms are proposed in case of pronounced inversion gas layer. Experimental results are described and compared with the proposed mechanisms.

Activity of MnOx–CeO2 catalysts in combustion of low concentrated methane

Due to its warming potential over 20 times higher than that of CO2, methane is classified as one of the most dangerous pollutants. Removal of methane emitted particularly from low calorific sources, such as coal mine ventilation air streams or dumping grounds, falls thus in line with the most important challenges of environmental catalysis. Main goal of this work was to verify the efficiency and to understand the catalytic behavior of a series of coprecipitated MnOx–CeO2 mixed oxide samples, containing nominally 30–80mol% of MnO2. A plethora of structural (XRD, RS), textural (BET), and spectroscopic (EPR, XPS, and RS) methods have been applied for sample characterization. Catalytic activity has been determined by TPSR in the temperature range from 100 to 700C. It was shown that catalytic activity of the investigated MnOx–CeO2 samples is strongly related to their structural heterogeneity and reducibility of various manganese centers coexisting within the surface MnOx clusters interacting with nanocrystalline CeO2.

Coal mine ventilation air methane combustion in a catalytic reverse flow reactor: Influence of emission humidity

The role of the humidity content on the performance of catalytic reverse flow reactors (RFRs) for the abatement of methane emissions from coal mines is studied in this manuscript. It has been demonstrated that this technique is very useful for the abatement, and even upgrading, of these emissions. However, the effect of humidity on the reactor performance has not been addressed yet, in spite of being well known that water is an inhibitor in catalytic combustion.Experimental studies in a lab-scale isothermal fixed bed reactor demonstrated that water decreases the activity of a palladium on alumina catalyst for the combustion of methane, but this inhibition is entirely reversible, results fitting well to a Langmuir–Hinshelwood kinetic model. Then, the influence of water was studied in a bench-scale RFR operating at near adiabatic conditions at different switching times (100–600s) and methane feed concentrations (2700–7200ppm). Finally, a mathematical model for the reverse flow reactor, including the kinetic model with water inhibition, has been validated using the experimental results. This model is of key importance for designing this type of reactors for the treatment of mine ventilation emissions.

Catalytic oxidation of coal mine ventilation air methane in a preheat catalytic reaction reactor

The results of experimental investigations on catalytic oxidation of coal mine ventilation air methane in a preheat catalytic reaction reactor is presented in this paper. The experimental system was located in the Energy Research Institute of Shandong University of Technology, which has been applied to investigate the effects of startup conditions such as the startup flow coefficient (0.3–0.5) and the startup power (10 kW–20 kW) on the startup process within the preheat catalytic reaction reactor. The average temperature distribution of catalytic oxidation bed and the minimal startup power were measured and the effects of operating conditions such as the space velocity (2600h−1 to 11,500 h−1) and the methane concentration (0.8%–1.2%) were experimentally investigated. Moreover, the methane conversion rate and the average temperature of the catalytic oxidation bed were discussed and the critical space velocity value and the critical methane concentration value were determined.

Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor

This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h) and catalytic oxidation bed average temperature (20°C to 560°C) within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry.

Enrichment and Separation of Coal Mine Ventilation Methane and Engineering Education

Due to the large flow, low concentration, low enrichment efficiency, potential safety hazards and the difficulty of comprehensive utilization, it is a big challenge for the development and application of enrichment and separation technology for coal mine ventilation methane (CMVM) at home and abroad. And many countries paid more and more attentions to resolve this problem. In this paper, we comprehensively introduce the research progress in the field of gas enrichment and separation of CMVM, and analyze the related research and application situation. Then, we put forward the enrichment and separation of CMVM in the future development will focus on high efficient adsorbent and adsorption & separation & enrichment technology and equipment, etc. in order to effectively form the system technology of separation & enrichment of CMVM. So we can provide technical support and auxiliary equipment for the domestic related enterprises, and ensure the mine safety and CMVM utilization. The application of CMVM in the laboratory can make mining engineering students learn how to use environmental technology to realize energy saving and emission reduction in coal mine.

DFS-Based Partition Method of Coalmine Ventilation Safety SubRegion

According to functional characteristics of different regions of the ventilation network, the complicated ventilation network can be further divided into non-overlapping and exhaustive safety subregions, which can provide scientific basis on classification guidance for ventilation analysis in a concise point of view. Therefore, it is of great application significance. Specifically, a method is proposed to divide safety subregions of the ventilation network. Then, six different safety subregions are defined, and they are air-inlet subregion, air-outlet subregion, air-consuming subregion, upstream of air-consuming subregion, downstream of air-consuming subregion and bypass subregion. After that, with an air-consuming spot (working face and heading face) as the center, depth-first search (DFS) algorithm is adopted to perform traversal analysis on coalmine ventilation network. Besides, ventilation network partition is achieved in combination with safety subregion partition algorithm. The method proposed here can be used for coalmine safety production analysis and management. Finally, Huangling coalmine is taken as an example to verify the correctness and feasibility of the method proposed.

A Study on Application of Real-Time Online Analysis of Ventilation Safety Data Based on Coalmine Monitoring System

Due to poor coalmine monitoring system data utilization and relatively high threshold for application of most application software in ventilation safety field, a multi-perspective coalmine ventilation management technology, with the goal of daily ventilation safety management, is introduced based on the real-time data from the coalmine monitoring system. Specifically, data acquisition unit is adopted to collect monitoring data in a real-time manner, and then integration of ventilation and coalmine gas data is made. After that, real-time online data analysis and display can be realized by using smart guidance and multi-screen linkage technologies according to chained features of the data. In this way, daily management interfaces based on specialized knowledge are shown in a friendly manner. Therefore, the technology proposed here can greatly improve coalmine management level and work efficiency. At the end, Huangling No. 2 coalmine is taken as an example to validate the relative technologies.

Addressing barriers to global deployment of best practices to reduce methane emissions from coal mines

Low energy prices coupled with a lack of carbon financing options have led to shuttering many emission-reducing projects located around the world at gassy coal mines. In late 2013, the Global Methane Initiative (GMI) Coal Subcommittee organized a panel of experts to discuss issues related to investment in coal mine methane (CMM) and ventilation air methane (VAM) emission reduction. The consensus of the panel is that the precipitous fall in Clean Development Mechanism (CDM) carbon prices from the 2011 high of €15 to the 2013 low of €0.50 has had a severe impact on project development and maintenance. Nevertheless, the CDM process demonstrated that carbon financing works, and there are hopeful signs that regional and national markets may provide incentives for renewed CMM and VAM project development. The GMI Coal Subcommittee actively seeks solutions to the challenges facing CMM and VAM emission reduction projects and offers support to its stakeholders through meetings, publications and training.

Coal-packed methane biofilter for mitigation of green house gas emissions from coal mine ventilation air.

Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min−1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m−3 empty bed h−1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min−1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.

Catalytic properties of Pd supported on hexaaluminate coated alumina in low temperature combustion of coal mine ventilation air methane

Palladium supported on γ-Al2O3 has been demonstrated as most active catalyst for catalytic combustion of methane. However, the sintering of support and PdO seriously affects its activity. We prepared a composite Pd/hexaaluminate/Al2O3 catalyst and compared its catalytic activity as well as sintering behavior with Pd/Al2O3. This composite catalyst exhibits higher activity and better resistance to sintering. The effect of water vapor presented in feed has also been investigated.

Balanced Ventilation Principle in the Application of Shigetai Coal Mine Ventilation System Optimization

In order to reduce Shigetai coal mine ventilation resistance of mine ventilation system, using balanced ventilation principle Shigetai coal mine ventilation resistance of mine ventilation system was analysed and balanced, and the balanced ventilation resistance measure mine ventilation resistance in 2014-2015 simulation calculation. Results suggest that balanced ventilation measures implemented in mine ventilation resistance, coal mine ventilation resistance in the next two years not only with increased ventilation line length increases, but lower. Visible, balanced ventilation of mine has better technical and economic results are obvious, merits promotion.

Research and Application of Ventilation Simulation and Monitoring System in Chensilou Coal Mine

Mine ventilation simulation system is a set of advanced, reliable and practical ventilation simulation system, which has a function of ventilation system simulation and visualization. It solved the technical problems such as automatic establishment and management of the topological relations, automatic identification of diagonal connection and air distribution according to demand under fixed cut set. According to the complexity of ChenSiLou coal mine ventilation system, the detailed analysis research is carried on. Mine ventilation simulation system has a successful connection with the mine monitoring system, realizing the real-time monitoring and real-time query. The technology is taken to optimize and transform the ventilation system of the mine. To ensure that the optimization and transformation of the ventilation system of the mine are carried out successfully, it simulated the ventilation system reconstruction scheme of the mine .The final plan is determined and has obtained the good effect of field application.

Catalytic or thermal reversed flow combustion of coal mine ventilation air methane: What is better choice and when?

The paper presents a comparison of the two options of reverse flow reactors destined for the utilization of coal mine ventilation air methane by catalytic (CFRR) or thermal (TFRR) combustion. It has been shown that both solutions have advantages and drawbacks. The use of the catalyst significantly decreases reactor temperature and makes the operation becomes to be autothermal for methane concentrations lower than in TFRR (even as low as over 0.06vol.%). On the other hand when methane is combusted, particularly if average concentration is higher than ca. 0.4vol.% the maximum temperature in the reactor appears to be too high for available cheap catalysts, while the use of the noble metals as active components (e.g. Pd) is not economically viable. Moreover lifetime of the catalysts is much lower than of the inactive heat exchange packing. For TFRR autothermicity threshold is higher (ca. 0.2vol.%) but it enables cost-effective heat recovery if CH4 concentration is higher than approx. 0.4vol.%. In conclusion, the paper states that for lower VAM concentrations, when only greenhouse gas mitigation is an aim of combustion CFRR can have some advantages over TFRR. Should the heat recovery be seriously taken into account the TFRR is economically and technically the most advantageous solution, however.

Statistical Analysis for Ventilation Resistance Characteristics of Bolting and Shotcrete Roadway in Nanyangpo Coal Mine

The statistical analysis for frictional resistance of bolting and shotcrete roadway is carried out by using the software of SPSS and statistical principle and combining the coal mine ventilation theory with the actual situation in Nanyangpo coal mine. The results show that the frictional resistance coefficient does not follow normal distribution and the 95% confidence interval is 0.0063~0.0087 N.s2/m4 for frictional resistance coefficient of bolting and shotcrete roadway. The comparison analysis of hectometer friction ventilation resistence is carried out between the statistical results with the actual measurement data in Nanyangpo Coal Mine, and its correlation is highly significant. It verifies that the statistical results is right. It has important application value for increasing the ventilation management level and ensuring the safety production of coal mining enterprises.

Study on the Coal Mine Ventilation Air Methane Utilization Technologies Based on Flow-Reversal Oxidation Principle

There is a huge amount of coal mine ventilation air methane emitted into the atmosphere directly each year in china, not only causes a lot of energy was wasted, but also do severe harm to the protection of the environment. The Utilization Technologies of coal mine ventilation air methane (VAM) are receiving more and more attention from people, Aiming at the domestic and international development status of VAM utilization, Thermal flow reversal reactor (TFRR) and catalytic flow reversal reactor (CFRR) are introduced, as two kind of flow-reversal oxidation technology which are the most popular and used widely. The economic and applicability about service life, total cost, space and performance of device are comparative analyzed, and illustrate the trends about the technology of flow-reversal oxidation of VAM from two aspects: to solve the problem of running stability well and improve its work efficiency reasonably. Finally, this paper outlines the future prospect for the development of this technology.

The Theoretical Study of Noise Control Engineering Design

Mine ventilation system is serious pollution to the surrounding environment. Due to the air flow rate, high speed, strong noise radiation. In addition to the scientific and reasonable design for muffler, ventilation resistance loss calculation is one of the key successful factors of project design, in order to eliminate the noise pollution of mine ventilation system.In recent years,people's awareness level of the harm of noise rises ceaselessly, the environmental protection departments also gradually enlarges the management and punishment to noise pollution.The noise control of coal mine ventilation system with strong radiation and harm has become a pressing matter of the moment. Because the theory calculation of noise control design is fuzzy, Some environmental protection company implement noise control by virtue of experience or imitation of other engineering, leading to a series of problems, such as noise control can not reach the design standard, large ventilation resistance, energy consumption increased, regeneration noise exceed the standard, system vibration. Based on the systematic study for engineering design, i summed up the theory calculation rule for the coal mine ventilation system noise control, as reference to technical personnel.