Memory Effect Stability on Hydrate-Based Coal Mine Methane Separation for Reducing Direct CMM Emission

2010 ◽  
Vol 113-116 ◽  
pp. 897-903 ◽  
Author(s):  
Qiang Wu ◽  
Bao Yong Zhang
Keyword(s):  
Pressure Drop ◽  
Memory Effect ◽  
Coal Mine ◽  
Gas Hydrate ◽  
Induction Time ◽  
Global Environment ◽  
Stability Conditions ◽  
Coal Mine Methane ◽  
Dissociation Temperature ◽  
The Stability

A new hydrate-based gas separation (HBGS) method for recovering methane from low-concentration CMM was proposed. The objective of this study is to investigate the influence of the temperature increase, agitation, and pressure drop on the stability of memory effect. Results showed that (1) when the dissociation temperature is not higher than 25.00 °C, the decreases of subcooling and induction time in gas hydrate nucleation range from 0.16 to 1.06 °C, and 1.75 to 88.92min, respectively. But when the dissociation temperature is higher than 25.00 °C, the memory effect is destroyed notably; (2) the agitator type and agitation show little influence on the stability of memory effect; (3) the pressure drop renders notable influence on the stability of memory effect. The present study provides stability conditions of memory effect that will contribute to CMM utilization and to benefit for local and global environment.

scholarly journals Bottom-Up Estimates of Coal Mine Methane Emissions in China: A Gridded Inventory, Emission Factors, and Trends

2019 ◽  
Vol 6 (8) ◽  
pp. 473-478 ◽  
Author(s):  
Jianxiong Sheng ◽  
Shaojie Song ◽  
Yuzhong Zhang ◽  
Ronald G. Prinn ◽  
Greet Janssens-Maenhout
Keyword(s):  
Coal Mine ◽  
Methane Emissions ◽  
Emission Factors ◽  
Bottom Up ◽  
Coal Mine Methane

Combustion Characteristics of Coal Mine Methane in a Preheated-Burner Packed with Raschig Rings

2021 ◽  
Author(s):  
Huaming Dai ◽  
Huiwei Zhu ◽  
Pan Yang ◽  
Hongchao Dai ◽  
Song He ◽  
...  
Keyword(s):  
Coal Mine ◽  
Combustion Characteristics ◽  
Coal Mine Methane

scholarly journals Causality and stability conditions of a conformal charged fluid

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Farid Taghinavaz
Keyword(s):  
Chemical Potential ◽  
Second Law Of Thermodynamics ◽  
Dense Medium ◽  
Wave Number ◽  
Second Law ◽  
Stability Conditions ◽  
Charged Fluid ◽  
Large Wave ◽  
The Stability ◽  
Large Wave Number

Abstract In this paper, I study the conditions imposed on a normal charged fluid so that the causality and stability criteria hold for this fluid. I adopt the newly developed General Frame (GF) notion in the relativistic hydrodynamics framework which states that hydrodynamic frames have to be fixed after applying the stability and causality conditions. To do this, I take a charged conformal matter in the flat and 3 + 1 dimension to analyze better these conditions. The causality condition is applied by looking to the asymptotic velocity of sound hydro modes at the large wave number limit and stability conditions are imposed by looking to the imaginary parts of hydro modes as well as the Routh-Hurwitz criteria. By fixing some of the transports, the suitable spaces for other ones are derived. I observe that in a dense medium having a finite U(1) charge with chemical potential μ0, negative values for transports appear and the second law of thermodynamics has not ruled out the existence of such values. Sign of scalar transports are not limited by any constraints and just a combination of vector transports is limited by the second law of thermodynamic. Also numerically it is proved that the most favorable region for transports $$ {\tilde{\upgamma}}_{1,2}, $$ γ ˜ 1 , 2 , coefficients of the dissipative terms of the current, is of negative values.

scholarly journals The Security of Energy Supply from Internal Combustion Engines Using Coal Mine Methane—Forecasting of the Electrical Energy Generation

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3049
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Klaudia Zwolińska ◽  
Rafał Łuczak ◽  
Zbigniew Kuczera
Keyword(s):  
Coal Mine ◽  
Predictive Models ◽  
Coalbed Methane ◽  
Internal Combustion Engines ◽  
Drainage System ◽  
Production Capacity ◽  
Methane Combustion ◽  
Economic Benefits ◽  
Electricity Production ◽  
Coal Mine Methane

Increasing emissions from mining areas and a high global warming potential of methane have caused gas management to become a vital challenge. At the same time, it provides the opportunity to obtain economic benefits. In addition, the use of combined heat and power (CHP) in the case of coalbed methane combustion enables much more efficient use of this fuel. The article analyses the possibility of electricity production using gas engines fueled with methane captured from the Budryk coal mine in Poland. The basic issue concerning the energy production from coalbed methane is the continuity of supply, which is to ensure the required amount and concentration of the gas mixture for combustion. Hence, the reliability of supply for electricity production is of key importance. The analysis included the basic characterization of both the daily and annual methane capture by the mine’s methane drainage system, as well as the development of predictive models to determine electricity production based on hourly capture and time parameters. To forecast electricity production, predictive models that are based on five parameters have been adopted. Models were prepared based on three time variables, i.e., month, day, hour, and two values from the gas drainage system-capture and concentration of the methane. For this purpose, artificial neural networks with different properties were tested. The developed models have a high value of correlation coefficient. but showed deviations concerning the very low values persisting for a short time. The study shows that electricity production forecasting is possible, but it requires data on many variables that directly affect the production capacity of the system.

scholarly journals Iterative stability analysis for general polynomial control systems

2021 ◽  
Author(s):  
Bo Xiao ◽  
Hak-Keung Lam ◽  
Zhixiong Zhong
Keyword(s):  
Stability Analysis ◽  
Lyapunov Function ◽  
Control Systems ◽  
Polynomial System ◽  
Stability Conditions ◽  
General Polynomial ◽  
Main Challenge ◽  
Detailed Simulation ◽  
Feasible Solutions ◽  
The Stability

AbstractThe main challenge of the stability analysis for general polynomial control systems is that non-convex terms exist in the stability conditions, which hinders solving the stability conditions numerically. Most approaches in the literature impose constraints on the Lyapunov function candidates or the non-convex related terms to circumvent this problem. Motivated by this difficulty, in this paper, we confront the non-convex problem directly and present an iterative stability analysis to address the long-standing problem in general polynomial control systems. Different from the existing methods, no constraints are imposed on the polynomial Lyapunov function candidates. Therefore, the limitations on the Lyapunov function candidate and non-convex terms are eliminated from the proposed analysis, which makes the proposed method more general than the state-of-the-art. In the proposed approach, the stability for the general polynomial model is analyzed and the original non-convex stability conditions are developed. To solve the non-convex stability conditions through the sum-of-squares programming, the iterative stability analysis is presented. The feasible solutions are verified by the original non-convex stability conditions to guarantee the asymptotic stability of the general polynomial system. The detailed simulation example is provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed approach is more capable to find feasible solutions for the general polynomial control systems when compared with the existing ones.

scholarly journals Hydrate-based Methane Recovery from Coal Mine Methane Gas in Scale-up Equipment with Bubbling

2017 ◽  
Vol 105 ◽  
pp. 4983-4989 ◽  
Author(s):  
Jing Cai ◽  
Chungang Xu ◽  
Zhiming Xia ◽  
Zhaoyang Chen ◽  
Xiaosen Li
Keyword(s):  
Coal Mine ◽  
Scale Up ◽  
Methane Recovery ◽  
Coal Mine Methane ◽  
Methane Gas
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