The Experts below are selected from a list of 26394 Experts worldwide ranked by ideXlab platform
Wen Nie - One of the best experts on this subject based on the ideXlab platform.
-
Gas Pressure prediction model for carbon dioxide Injection in a large scale coal matrix experiment
Rock Mechanics and Rock Engineering, 2019Co-Authors: Wen Nie, Lin Chen, Hongwei Yang, Yidu Hong, Yulong ChenAbstract:Carbon dioxide Injection, Gas flow, and adsorption of CO2 in a coal matrix are modelled by a large-scale physical experiment. The process primarily comprises an increase in the Gas Pressure from an unsaturated to a saturated status during Gas Injection followed by a reduction in the Gas Pressure due to the adsorption of CO2 after the cessation of Gas Injection. We developed a straightforward and effective calibration-based Gas Pressure model for the spatio-temporal prediction of CO2 in a coal matrix. The Nash–Sutcliffe efficiency of the models for predicting Gas Pressure is between 0.931 and 0.998. The results indicate that the spatio-temporal distribution of Gas Pressure in the coal matrix mainly relates to the Gas Pressure injected, geological boundary conditions, initial geo-stress, and Gas type. The Gas concentration tends to increase in high Earth stress and boundary areas during Gas Injection, whereas the Gas adsorption rate is high in areas of low Earth stress. The Gas adsorption rate of the coal matrix decreases as the Gas Injection content and Gas Injection time increase; improvement of the Gas Injection Pressure can boost the Gas adsorption to some extent. This model can explain or predict the behaviour of Gas in a coal matrix depending on the matrix density, and it has the potential to simulate Gas behaviour in a large-scale undisturbed coal sample considering the structure (joints and cleats) of the coal.
J F Harrington - One of the best experts on this subject based on the ideXlab platform.
-
final report of forge wp4 1 1 the stress path permeameter experiment conducted on callovo oxfordian claystone
2012Co-Authors: Robert J. Cuss, J F HarringtonAbstract:This report describes in detail the stress-path permeameter (SPP) apparatus and the test programme conducted on Callovo-Oxfordian (COx) Claystone from the Bure underground research laboratory (URL) in France. Funding for this study has been provided by the French radioactive waste management operator, Andra, the European Union (FORGE Project, Project number 230357) and the British Geological Survey through its well-founded laboratory programme and the Geosphere Containment project (part of the BGS core strategic programme). The results from the first test conducted using the SPP showed that COx has a very pronounced time-dependent component of deformation. This had implications for the following test conducted on COx and also has implications when comparing tests that have been deformed at a much faster rate. Test SPP_COx-1 was conducted with water as a test permeant at constant pore-Pressure along a pre-defined stress-path. Volumetric deformation was observed during 16 steps along the stress-path, with considerable time-dependent deformation and anisotropy seen in radial strain. The 16th stage saw the sample fail through the formation of a fracture after the sample had experienced constant stress conditions for 5.5 days; this emphasises the observed time dependent deformation. The results from test SPP_COx-2 clearly showed that the sample dilated at the onset of Gas propagation; dilatancy was observed in three radial and one axial direction. A component of this volumetric deformation was associated with changes in pore-Pressure. However, pore-Pressure variation cannot account for the full amount of strain recorded and a proportion of the strain observed was the result of Gas migration by dilatant pathway formation. Prior to the sample attaining steady-state flow, outflow from the sample slowly reduced and the conductive features experienced self-sealing. Gas Injection Pressure was raised and back-Pressure was carefully lowered; neither course of action re-initiated flow through the sample.
-
final report of forge wp4 1 1 the stress path permeameter experiment conducted on callovo oxfordian claystone
2012Co-Authors: Robert J. Cuss, J F HarringtonAbstract:This report describes in detail the stress-path permeameter (SPP) apparatus and the test programme conducted on Callovo-Oxfordian (COx) Claystone from the Bure underground research laboratory (URL) in France. Funding for this study has been provided by the French radioactive waste management operator, Andra, the European Union (FORGE Project, Project number 230357) and the British Geological Survey through its well-founded laboratory programme and the Geosphere Containment project (part of the BGS core strategic programme). The results from the first test conducted using the SPP showed that COx has a very pronounced time-dependent component of deformation. This had implications for the following test conducted on COx and also has implications when comparing tests that have been deformed at a much faster rate. Test SPP_COx-1 was conducted with water as a test permeant at constant pore-Pressure along a pre-defined stress-path. Volumetric deformation was observed during 16 steps along the stress-path, with considerable time-dependent deformation and anisotropy seen in radial strain. The 16th stage saw the sample fail through the formation of a fracture after the sample had experienced constant stress conditions for 5.5 days; this emphasises the observed time dependent deformation. The results from test SPP_COx-2 clearly showed that the sample dilated at the onset of Gas propagation; dilatancy was observed in three radial and one axial direction. A component of this volumetric deformation was associated with changes in pore-Pressure. However, pore-Pressure variation cannot account for the full amount of strain recorded and a proportion of the strain observed was the result of Gas migration by dilatant pathway formation. Prior to the sample attaining steady-state flow, outflow from the sample slowly reduced and the conductive features experienced self-sealing. Gas Injection Pressure was raised and back-Pressure was carefully lowered; neither course of action re-initiated flow through the sample.
Ming Chia Lai - One of the best experts on this subject based on the ideXlab platform.
-
experimental study of the effects of natural Gas Injection timing on the combustion performance and emissions of a turbocharged common rail dual fuel engine
Energy Conversion and Management, 2014Co-Authors: Bo Yang, Xing Wei, Yifu Liu, Ke Zeng, Ming Chia LaiAbstract:Abstract Natural Gas combustion with pilot ignition has been considered to be one of the most promising ways to utilize natural Gas in existing diesel engine without serious engine modification and it has been widely researched all over the world. In this study, three experiments of different loads (BMEP 0.240 MPa, 0.480 MPa and 0.767 MPa) were performed on a 2.8 L four-cylinder, natural Gas manifold Injection dual-fuel engine to investigate the effects of natural Gas Injection timing on engine combustion performance and emissions. The pilot Injection parameters (pilot Injection timing and Pressure) and natural Gas Injection Pressure remain constant at a speed of 1600 rpm in the experiment. The cylinder Pressure, HRR, CoVimep, flame development duration, CA50 and brake thermal efficiency were analyzed. The results indicated that under low and part engine loads, the flame development duration and CA50 can be reduced by properly retarding natural Gas Injection timing, while the CoVimep increased with retarded natural Gas Injection timing. As a result, the brake thermal efficiency is increased and the combustion stability slightly deteriorates. Meanwhile, under low and part engine loads, PM emissions in the dual-fuel engine is much lower than that in conventional diesel engines, furthermore, at high load, the PM emissions are near zero. CO and HC emissions are reduced with retarded natural Gas Injection timing under low and part loads, however, NOx emissions are slightly increased. Under high load, the flame development duration and CA50 are obviously prolonged with retarded natural Gas Injection timing companied with a deterioration of brake thermal efficiency. CO and HC emissions are not significantly varied with retarded natural Gas Injection timing under high load, except that NOx emissions decreased slightly.
Liang Wang - One of the best experts on this subject based on the ideXlab platform.
-
experimental investigation of co2 Injection into coal seam reservoir at in situ stress conditions for enhanced coalbed methane recovery
Fuel, 2019Co-Authors: Zhengdong Liu, Yuanping Cheng, Yongkang Wang, Liang WangAbstract:Abstract CO2 geological sequestration is an effective method to reduce the concentration of CO2 in the atmosphere. The Injection of CO2 into CH4-containing coal seams also named CO2-ECBM (CO2 Enhanced Coalbed Methane Recovery), allows the storage of CO2 and the enhancement of CH4 recovery. Due to complex geological environment of the site, dynamic variation of CH4 and CO2 can hardly be monitored in real time during CO2 Injection into coal seams. Therefore, this paper conducted experimental studies were carried out on cuboid coal samples with a size of 300 ∗ 70 ∗ 70 mm via a self-developed experimental device which can simulate in-situ stress and temperature conditions. In the experiment, different adsorbed Gases (CH4 and CO2) were applied to determine the variation of permeability values under various load stresses and pore Pressures. Results proved that the coal had greater adsorption capacity to CO2 than to CH4. The injected CO2 occupied the original adsorption site of CH4, thus leading to the rapid discharge of CH4. Meanwhile, real-time dynamic monitoring was also performed on Gas parameters in coal under different Gas Injection Pressures to obtain variation laws of pore Pressure, Gas flow rate and concentration at the outlet with the increment of injected CO2. The results reveal that with the increase of injected CO2, pore Pressure tended to equilibrium while CH4 flow rate and concentration at the outlet gradually fall to zero. Therefore, CO2 Injection into the coal mass can effectively improve the recovery of CH4. In addition, variations of Gas flow rate and concentration at the outlet with the displacement ratio of Gas volume under different Gas Injection Pressures suggested that the enhancement of Gas Injection Pressure boosted discharge efficiency of CH4 from the coal mass and CO2 consumption. Furthermore, inspired by the competition relationship between engineering efficiency and CO2 consumption, we think a reasonable and effective economic cost model can be established as an effective method to guide the selection of Gas Injection Pressure in the future. Hence, the experimental results have guiding significance for better understanding and application of CO2-ECBM technology.
Yulong Chen - One of the best experts on this subject based on the ideXlab platform.
-
Gas Pressure prediction model for carbon dioxide Injection in a large scale coal matrix experiment
Rock Mechanics and Rock Engineering, 2019Co-Authors: Wen Nie, Lin Chen, Hongwei Yang, Yidu Hong, Yulong ChenAbstract:Carbon dioxide Injection, Gas flow, and adsorption of CO2 in a coal matrix are modelled by a large-scale physical experiment. The process primarily comprises an increase in the Gas Pressure from an unsaturated to a saturated status during Gas Injection followed by a reduction in the Gas Pressure due to the adsorption of CO2 after the cessation of Gas Injection. We developed a straightforward and effective calibration-based Gas Pressure model for the spatio-temporal prediction of CO2 in a coal matrix. The Nash–Sutcliffe efficiency of the models for predicting Gas Pressure is between 0.931 and 0.998. The results indicate that the spatio-temporal distribution of Gas Pressure in the coal matrix mainly relates to the Gas Pressure injected, geological boundary conditions, initial geo-stress, and Gas type. The Gas concentration tends to increase in high Earth stress and boundary areas during Gas Injection, whereas the Gas adsorption rate is high in areas of low Earth stress. The Gas adsorption rate of the coal matrix decreases as the Gas Injection content and Gas Injection time increase; improvement of the Gas Injection Pressure can boost the Gas adsorption to some extent. This model can explain or predict the behaviour of Gas in a coal matrix depending on the matrix density, and it has the potential to simulate Gas behaviour in a large-scale undisturbed coal sample considering the structure (joints and cleats) of the coal.
