Industrial Field Tests Research Articles

Research and practice of high-speed spiral composite drilling technology in complex and weak coal seams

In response to the difficult slag discharge and low hole formation rate encountered in the Wangpo Coal Mine, a study was conducted on high-speed spiral composite drilling technology. This study was integrated with the performance characteristics of the ZDY6000LR-type high-speed pit rig, resulting in the design of drill bits in three different specifications: Φ110/63.5 mm, Φ95/60.3 mm, and Φ88/50 mm. Additionally, the study optimized the three-wing drill pipe's feed speed, rotation speed, and airflow volume. The industrial field test, conducted on the 3206 working face of the Wangpo Coal Mine, resulted in the design of three drill bit combinations that exhibited high strength and stiffness. This design improvement led to enhanced hole integrity, elevated slag removal efficiency, and extended service life for both the drill pipe and bit. The high-speed spiral composite drilling technology, alongside the supporting equipment, effectively addresses the challenges of slag discharge and nozzle top drilling encountered during operations. It significantly improves the deep hole drilling rate, achieving a drilling depth of over 100 m with a success rate exceeding 70%. This technology provides vital support for the extraction of gas from coal seams within the mine. Notably, the Φ95/60.3 mm screw pipe and its corresponding drill bit demonstrated the optimal holeforming effect, with an average hole depth of 111.2 m and a hole formation rate of 90.9%. These findings offer valuable insights for drilling operations under similar conditions of complex and weak coal seams.

Prediction of the Penetration Radius of Cumulative Blasting.

To improve the efficiency of coal seam gas extraction, the influence characteristics of different factors on the penetration effect of cumulative blasting were determined and the hole spacing was effectively predicted; in this work, we used ANSYS/LS-DYNA numerical simulation software to establish the penetration model of cumulative blasting. Combined with an orthogonal design scheme, the crack radius prediction of cumulative blasting was studied. A prediction model for predicting the fracture radius of cumulative blasting based on three groups of different factors was established. The results showed that the primary and secondary order of factors that affected the fracture radius of cumulative blasting was as follows: ground stress > gas pressure > coal firmness coefficient. The penetration effect decreased with increasing ground stress and decreased with an increase in the gas pressure and coal firmness coefficient. The industrial field test was carried out. The gas extraction concentration increased by 73.4% after cumulative blasting, and the effective crack radius of cumulative blasting was approximately 5.5-6 m. The maximum error of the numerical simulation was 1.2%, and the maximum error of the industrial field test was 6.22%, which proved that the crack radius prediction model of cumulative blasting was correct.

Quantitative Characteristics of the Microstructure of Typical Chernozems Using Different Agricultural Technologies

The methodological possibilities of micromorphological soil research making it possible to analyze digital images of soil thin sections at a quantitative level are presented in this study. A new software Thixomet Pro has been tested for quantitative micromorphological study of sail on the example of soil thin sections from the surface horizons of Haplic Chernozem. Soil samples for preparing thin sections were collected on the territory of scientific and industrial field test plot for assessing the impact of agro technologies in grain crop rotation on soil properties (Kursk region, Russia). In the field test plot, conventional agro technology (real tillage) and no-till are compared. Soil sampling was carried out in two replications from depth of 10–15 cm. The analysis revealed the variability of microstructure of Haplic Chernozem in the size, shape and orientation of aggregates associated with the use of agricultural technologies with and without plowing in grain crop rotation. In the Сhernozem with no–till, aggregates are generally larger compared to the aggregates of Сhernozem with conventional agro technology. This is noted at all levels of comparison of direct seeding and conventional agricultural technology: in the minimum diameter, the fraction 1–2 mm prevails against 0.25–0.5 mm, respectively, in the average diameter, fractions 1–2, 2–3 and 3–5 mm prevail against 0.5–1 and 0.25–0.5 mm, respectively, in the maximum diameter, fractions 1–2, 2–3 and 3–5 mm prevail against 0.5–1, 0.25–0.5 and 1–2 mm, respectively. It is also shown that less rounded and isometric aggregates are formed during direct seeding. With direct seeding, the proportion of aggregates with a form factor of 0.2–0.4 is higher and the proportion of aggregates with a form factor of 0.4–0.6 is lower than with traditional technology. The proportion of subhorizontal aggregates in direct seeding is higher compared to traditional processing (54.3 and 34.1% respectively).

A new machine vision detection method for identifying and screening out various large foreign objects on coal belt conveyor lines

Large foreign object transporting by coal mine conveyor belt may lead to production safety hazards. To reduce safety accidents during coal mining, a large foreign object detection method based on machine vision is proposed in this paper. An adaptive weighted multi-scale Retinex (MSR) image enhancement algorithm is proposed to improve the captured image quality of the belt conveyor line. An improved multi-scale template matching algorithm is designed by combining the frame difference and area methods to screen and identify large foreign objects mixed in coals. The multi-layer perceptron (MLP) network optimized by the Gray Wolf algorithm is introduced to identify the large objects. Experimental results show that the identification accuracy reaches 98.8% for the large foreign objects. Furthermore, industrial field test is carried out in the Gaoyang coal mine, and the filed test results demonstrate that the identification accuracy of the proposed method is more than 95%. Hence, the proposed method meets the industrial detection requirements and can be used in practices for detecting the large foreign objects.

Asymmetric Damage Mechanisms and Prevention Technology in Large-Section Gob-Side Entry Retaining

Based on the deformation and damage characteristics of the surrounding rock in a large-section gob-side entry retaining and combined with field observations and an analysis of the dominant factors, an overall deformation control plan is formulated. The plan mainly includes a structure of high strength, high stiffness and high ductility for roadside support; the reinforcement of the roadway-in support; and the setup entry hydraulic fracturing pressure release mechanism and advanced long, horizontal borehole “fracturing-jet” pressure relief technology. Industrial field tests were completed taking Tangan coal mine as the engineering background. The research shows that the large-section gob-side entry retaining has the typical “asymmetric” overall deformation and damage characteristics, including top coal sinking along the inner side of the roadside support, the whole roadside support structure skewing, and even splitting damage; floor heaving; and the coal-side bolt support structure basically losing support ability and bulging out from the coal side. The dominant factors of deformation damage are disintegration of the floor mudstone by water and deflection deformation under horizontal stress, splitting damage in the concrete roadside support under asymmetric load, damage and expansion due to the insufficient strength of the coal side support, strong dynamic pressure on the roof, and the mutual influence of support and pressure relief. The industrial test shows that the deformation control scheme optimizes the stress environment of the gob-side entry retaining space, the deformation control effect is remarkable, and the roadside fully meets the reuse requirements.

Experimental Study on Floor Damage and Slurry Material Ratio Optimization in Deep and High Confined Water Mining

Deep mining has started in the Huaibei mining area, and the serious threat of high confined water on the floor to the coal seam is gradually increasing. Based on the deep confined water mining project at working face II633 of the Hengyuan coal mine, this paper theoretically analyzes the damage depth of the floor and the risk of water inrush from the floor. The best proportion of grouting materials was quantitatively optimized by indoor experiments, and an industrial field test was conducted to judge the grouting effect. The results show that the failure depth of the bottom plate calculated by theoretical analysis is 31.73 m; a single factor test and a response surface optimization design method determined the best value of each index: water cement ratio 0.8, bentonite 2%, water reducer 0.6%, sodium silicate 2%. The damage depth of the bottom plate after grouting is 18.83~20 m, according to the field monitoring by the strain method. The optimized slurry significantly reduces the damage depth of the floor, ensures the safe and efficient mining of the coal seam above the high–pressure water, and has a high reference value for the safe mining of the coal seam under similar geological conditions.

Load-Adapted Surface Modifications to Increase Lifetime of Forging Dies

Diffusion treatments offer possibilities to enhance the performance and the service lifetime of hot forging tools. In combination with coating after nitriding, the surface layer hardness can be further increased. Within the scope of this study, a surface layer hardness above 2,000 HV0.005 was determined for borided or DLC (diamond-like carbon) coated surface layers. An increased surface layer hardness improves the abrasive wear resistance of forging dies. Furthermore, the plastic deformation of thermally softened forging die areas can be reduced. Beside these desirable effects, the ductility of diffusion treated or coated near surface layers is reduced and thermomechanical cracks are promoted. Therefore, additional approaches were developed to improve the thermomechanical crack behaviour of forging dies. Patterned plasmanitriding by the use of coverages to prevent areas from nitrogen diffusion, new combination processes of plasmanitrocarburizing (PNC) followed by plasmanitriding (PN) and the innovative boriding were investigated on different abstraction levels. A system of several testing rigs was set up to enable the abstraction of the thermal shock conditions in different stages. The patterned nitriding, boriding and combination plasma process (PN + PNC) were evaluated in a series of industrial field tests to derive recommendations for suitable tool treatments.

Integrated Collaborative Control of “Shielding-Filling-Grouting” of 1 km Deep Large-Section Roadways: A Case Study

Effective control of deformation failure of surrounding rock in deep roadway has become an important prerequisite for the safe and efficient development of deep coal resources. In this study, the field measurement of the study area’s in-situ stress was carried out for the specific engineering geological conditions of the KCM −967 m level west-wing main track roadway. The west-wing main track roadway’s full-section deformation failure features were summarized and analyzed, and the main roadway’s surrounding rock nonlinear deformation failure mechanism was revealed from the perspective of elastoplastic mechanics. Based on that, a set of highly targeted integrated collaborative control technology of “shielding-filling-grouting” system was proposed. The industrial field test revealed that, after the above integrated collaborative control scheme was adopted, there was no strong deformation failure on the surface of the main roadway surrounding rock and deep rock mass, which played the role of active and passive support collaborative control, reduced the subsequent repeated repair and maintenance workload of the roadway, and satisfied the needs of long-term safe and efficient production of the mine. The results obtained provide a reference for the control of surrounding rock of deep and large-section roadways in other mining areas.

Study on Pressure Relief Technology of High-Pressure Water Jet of Residual Coal Pillar in Overlying Goaf in Close Seam Mining

To solve the problem of strong ground pressure behaviour under a residual coal pillar in the overlying goaf of a close-distance coal seam, this paper proposes the technology of weakening and relieving the residual coal pillar in the overlying goaf by a high-pressure water jet. Based on the geological occurrence of the No. 3 coal seam and mountain No. 4 coal seam in the Yanzishan coal mine, the high-pressure water jet pressure relief technology of residual coal pillars in the overlying goaf of close-distance coal seams was studied by theoretical analysis and field industrial tests. First, the elastic-plastic zone of the residual coal pillar and the stress distribution law of the floor are obtained by theoretical analysis, and the influence degree of the residual coal pillar on the support of the lower coal seam working face is revealed. Then, a high-pressure water jet combined with mine pressure is proposed to weaken the residual coal pillar. Finally, through the residual coal pillar hydraulic cutting mechanical model and “double-drilling double-slot” model, the high-pressure water jet drilling layout parameters are determined, and an industrial field test is carried out. The single knife cutting coal output and 38216 working face hydraulic support monitoring data show that high-pressure hydraulic slotting can weaken the strength of the coal body to a certain extent, destroy the integrity of the residual coal pillar, cut off the load transmission path of the overlying strata, and reduce the working resistance of the hydraulic support under the residual coal pillar to a certain extent, which is beneficial to the safe mining of the working face.

Prediction Models of Barite Crystallization and Inhibition Kinetics: Applications for Oil and Gas Industry

Barite is one of the most common mineral scales in the oilfield and its formation can sequester toxic strontium (Sr) and radium (Ra). Various scale inhibitors are widely used to inhibit its formation. The inhibition efficiencies of 18 common inhibitors were tested using an improved kinetic turbidity method over broad oil and gas production conditions. A theoretical and a semi-empirical barite crystallization and inhibition model were developed for the 18 most used scale inhibitors. Both models can work under a broad range of production conditions and are carefully reviewed against all available experimental data. These models have shown wide applications in industrial operations, field testing, and laboratory testing. Using the new models and testing method, a novel fast inhibitor performance testing method was proposed and validated. Furthermore, the barite crystallization and inhibition models also work well to predict the inhibition performance of mixed inhibitors. This study not only advanced barite scale inhibition in an efficiency and low-cost way during oil and gas production, but also provided new insights on understanding the fate and transport of toxic Sr and Ra.

The virtual lands of Oz: testing an agribot in simulation

Testing autonomous robots typically requires expensive test campaigns in the field. To alleviate them, a promising approach is to perform intensive tests in virtual environments. This paper presents an industrial case study on the feasibility and effectiveness of such an approach. The subject system is Oz, an agriculture robot for autonomous weeding. Its software was tested with weeding missions in virtual crop fields, using a 3D simulator based on Gazebo. The case study faced several challenges: the randomized generation of complex 3D environments, the automated checking of the robot behavior (test oracle), and the imperfect fidelity of simulation with respect to real-world behavior. We describe the test approach we developed, and compare the results with the ones of the industrial field tests. Despite the low-fidelity physics of the robot, the virtual tests revealed most software issues found in the field, including a major one that caused the majority of failures; they also revealed a new issue missed in the field. On the downside, the simulation could introduce spurious failures that would not occur in the real world.

The Location Optimum and Permeability-Enhancing Effect of a Low-Level Shield Rock Roadway

High (low)-level roadways are effective gas control measures for coal seams with high outburst potential and low permeability. The spatial location of the low-level roadway directly determines the gas drainage efficiency and can affect the success of the whole engineering project. Currently, determining the location of a low-level roadway is based mostly on empirical engineering analogies and lacks relevant theoretical support. In this work, based on the Ji-15-24080 engineering project at the No. 10 Coal Mine of Pingdingshan Tian’an Coal Industry Co., Ltd., a numerical model for the location of a low-level roadway was established using ANSYS numerical software to analyze the stress distribution in the rock surrounding the conveyor roadway for the mining face and assess the permeability-enhancing effect of the low-level roadway when it is placed at different locations. A location directly beneath the conveyor roadway was found to provide a good location for a low-level shield roadway. In addition, a quantitative distance between the conveyor roadway and the low-level roadway can also be determined. These optimization results were then directly applied in the field. Relevant industrial field tests were conducted to determine fracture development, gas pressure and stability of the surrounding rock. The field test results confirm that the proposed location for a low-level shield roadway is reasonable. We recommend that when the low-level shield roadway is placed directly beneath a conveyor roadway, it should be within 50 m of the working face, and an effective support structure should be employed to support the rock surrounding the conveyor roadway to ensure the stability of the rock. We further recommend that, in the area in front of the working face, particularly within 25 m of the working face, densely distributed gas drainage boreholes should be drilled to drain gas from the coal seam to reduce the gas pressure and lower the outburst risk. The results of this work will provide guidance for similar engineering projects to determine the location of a low-level roadway and to ensure gas control.

The Tracking Ratio Station

In ratio control, the control objective is to keep the ratio between two signals, normally flow measurements, at a desired value in spite of variations in setpoints and load disturbances, and possible control signal saturations. This paper presents a new ratio control scheme, the Tracking Ratio Station, that manages to handle all these situations. It is also able to keep the ratio when one of the controllers takes a local setpoint or is switched to manual control. The Tracking Ratio Station determines the setpoints of the two flow loops so that the one with the largest control error follows the external setpoint, whereas the one with the smallest control error follows the process output of the opposite control loop. The paper illustrates the properties of the Tracking Ratio Station in terms of both simulations and industrial field tests.

Wear of different PVD coatings at industrial fine-blanking field tests

Thin hard physical vapor deposited (PVD) coatings play significant role on wear performance of fine-blanking punches in the presence of extremely high contact stresses. Nevertheless it seems that in blanking or fine-blanking the coatings are selected based on coincidence, trial-error-method or latest trends. There is limited information about planning and conducting the fine-blanking industrial field tests and measuring the wear of different coatings. In the present study a set of fine-blanking punches and laboratory specimens were prepared with three coatings – TiCN, nACRo and nACo. As substrate material Bohler S390 Microclean high speed steel was used. Coating mechanical properties (modulus of elasticity and nanohardness) were measured and wear rate with alumina ball was determined using the reciprocating sliding test. Wear of coatings was measured from punches after industrial use. All of the tested coatings showed high variance of wear. However coatings nACo and nACRo have better average wear resistance in fine-blanking compared with the well-known TiCN. Industrial field tests show correlation to the ratio elastic strain to failure H/E. DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7249

Wet gas overreading characteristics of a long-throat Venturi at high pressure based on CFD

Based on the operational conditions of the PetroChina Southwest Oil & Gas well field, this study aims to explore the wet gas flow overreading (OR) characteristics of a nonstandard long-throat Venturi by the means of computational fluid dynamics (CFD) technique. The studied prototype structure size is an inner diameter of 50mm, a diameter ratio of 0.4 and a throat length of 50mm. According to the field experiment, the simulation pressure is 3MPa gauge. Through a comparative study of the multiphase flow models and turbulence models, combined with the analysis of the Baker׳s flow regime and interparticle space under the field conditions, this paper eventually employed DPM model and Eulerian model for wet gas simulation, respectively, and RSM for turbulence model. An equivalent droplet diameter adjustment method was implemented to improve the precision of prediction. During post-processing, the liquid phase distributions and the wall pressure profiles were investigated. The numerical results indicate that the differential pressure in convergent section of long-throat Venturi by using DPM model is less than that by using Eulerian model, and the differential pressures in the divergent section by using the two models are analogous. Afterwards, the OR prediction correlations based on the differential pressure ratio method were proposed, and then compared and validated by the industrial field tests. The root mean square errors (RMSE) and the average relative errors predicted by Eulerian model were 4.24% and 3.78%, 5.69% and 5.01% by using DPM model, respectively. In conclusion, Eulerian model is more suitable for wet gas flow prediction. And some advice on the improvement of the multiphase flow simulation is provided to get a more preferable performance in wet gas flow prediction.

Cemented Filling Mining Technology in Continuous Miner Filling Mining Face

Based on interval arrangement characteristics of the mined branch roadways and pillars in continuous miner filling mining gob,the cemented filling mining thought which divided mining and filling both into two stages was put forward.The first stage was mining branch roadways and then filling gob with cemented materials in time, and the second stage was mining pillars and filling gob with the first stage filling body support when it meet designed strength. Industrial field test showed that branch roadways were smoothly mined and filled, filling body strength meet demand and pillars were safety mined out.Continuous miner filling mining technology could reache high production efficiency based on advantages of mining and filling parallel operation and filling spaces constructing easily.

Experimental Research on the Drag Reduction Mechanism of Natural Gas Drag Reduction Agent and Its Industrial Field Test

As environmental protection has drawn increasing attention all around the world, natural gas has been increasingly used for its high efficiency, cleanliness, and low cost. However, the frictional resistance in transportation causes a large loss of energy, thereby reducing the transportation capacity. To address this problem, this work analyzes the hydraulics of natural gas pipeline transportation, the regularity of the effects of a drag reduction agent (DRA) on the pipe inner-surface roughness, the relationship between the drag reduction effect and DRA injection technology (different doses and injection methods), and the flow pattern improvement regularity of the DRA membrane acting on the near-wall region of the pipeline. Through these studies, the fundamental reason for frictional resistance has been found, and the drag reduction mechanism has also been identified. Field test shows that the application of DRA could reduce the frictional loss by 12–16.5% in the gas pipeline transportation and raise the transportation efficiency by 8–12%.

A Shunt Active Power Filter with Enhanced Dynamic performance using Dual-Repetitive Controller and Predictive Compensation

In this paper, the configuration characteristic of shunt active power filter (APF) with split capacitor is analyzed, as well as its principle diagram and control module. In order to improve the dynamic performance of a control system and to eliminate multi-repetitive errors (MRE), a combination strategy based on dual-repetitive controller (DRC) and PI controller is presented. One repetitive controller is for ensuring the current tracking accuracy and the other one is for enhancing dynamic response. And for purpose of eliminating the system delay brought by the inverter and special control, an improved predictive compensation method is proposed by using the pre-compensated angel. Using this composite control strategy to carry on industrial prototype simulation and field test, the experimental result shows that system compensation could effectively reduce the total harmonic distortion (THD) values from 26.02%, 26.94% and 26.27% to 4.20%, 4.59% and 4.35% for each phase of the current. And the full response time are all less than 10ms, fully meeting the standard of IEEE-519. DOI: http://dx.doi.org/10.11591/ijpeds.v3i2.2930

Current development and application of chemical combination flooding technique

Abstract Great progress and success have been achieved in the fundamental study and field test of chemical combination flooding in recent years. In China, a low concentration ASP formula is employed to achieve ultra-low interfacial tension by the synergistic effect of alkali and surfactant. The viscosity of polymer solution prepared from produced water can meet the technological requirement when salt tolerance polymer is applied. ASP or SP flooding can increase both oil displacement efficiency and sweep volume. ASP pilot tests and industrial field tests in Daqing Oilfield have resulted in an oil recovery increase of 18.5%-26.5%. The chemical combination flooding has entered into the industrial promotion and application stage, with a series of supporting techniques formed in the field tests. The main challenges in this technique include short pump-checking period and difficulty in produced liquid handling and high cost. Micelle-polymer flooding as the major chemical combination flooding technique was applied abroad in the early stage of chemical flooding tests. However, the micelle-polymer flooding has not been applied widely due to its high cost. With the rise of oil price in recent years, low concentration chemical combination flooding has drawn more attention. Because of high temperature and high salinity in most reservoirs abroad where chemical combination flooding is used, high performance temperature and salt tolerance oil displacement agents are the bottleneck for future chemical flooding.

Carbon monoxide formation and emissions during waste incineration in a grate-circulating fluidized bed incinerator

This paper presents an experimental study of carbon monoxide (CO) formation and emissions in both grate drying bed incinerators and circulating fluidized bed (CFB) incinerators to simulate the two key parts of a combined grate and circulating fluidized bed (grate-CFB) incinerator in order to investigate pollutant emission control in municipal solid waste (MSW) combustion that occurs in a grate-CFB incinerator utilizing a patented technology. Polyvinyl chloride, polystyrene, kitchen waste, paper, textile, etc. were chosen to simulate the MSW. The effects of temperature, air staging, and moisture on the CO formation and emissions were analysed for both the grate drying bed combustion and the CFB combustion. In the grate drying bed, the low temperatures increased the carbon to CO conversion rate which also increased slightly with the moisture content. Industrial field tests in a commercial grate-CFB incinerator showed that the CO concentration at the grate drying bed exit was very high and decreased along furnace height. The carbon to CO conversion rates were 0-20% for the grate drying bed which exceeded the range of 0.8-16% measured in a grate drying bed exit of the commercial grate-CFB incinerator tests. In the commercial grate-CFB incinerator tests, at excess air ratios ranging from 1.5-2.0 or more, the CO emissions decreased to a low and stable level, whose corresponding carbon to CO conversion rates were far lower than 0-10%. The low CO emission is one of the factors enabling the polychlorinated dibenzodioxin/polychlorinated dibenzofuran emissions to satisfy the Chinese national regulations.