Long-distance Pipeline Transportation Research Articles

Study on the suspending mechanism of gangue particle in coal-based solid waste slurry

In China's coal mine backfill mining projects, certain mines demonstrate an extensive filling distance that exceeds 3000 m. However, there are few researches concerning the theoretical underpinnings for slurry long-distance pipeline transportation. Gangue particles suspending in filling slurry is the prerequisite for successful long-distance pipeline transportation. This paper conducts theoretical researches on the heightened sensitivity issue of particle settling within coal-based solid waste filling slurry (CSWFS) for long-distance pipeline transportation, which can easily lead to unstable slurry concentration then pipe blockage or bursting accidents. The mechanical model for particle settling and critical non-settling particle diameter for long-distance pipeline transportation are developed based on the "solid-liquid two-phase carrier suspension fluid", and reveal the intrinsical mechanism of particle settling within CSWFS for long-distance pipeline transportation. Through the calculation of the mechanical model for critical non-settling particle diameter and particle settling, coupled with the particle diameter screening experiment, the value of critical non-settling particle diameter is determined to be 0.0067 m, and the density of solid-liquid two-phase carrier suspension fluid is 1712.37 kg/m3. The CSWFS is classified as a semi-stable slurry, lacking time-dependent suspending state required for long-distance pipeline transportation, which could lead to pipe blockage accidents. Further research into effective methods is urgently required to ensure adequate safety and adaptability for long-distance pipeline transportation of CSWFS.

Development and Outlook for Pipeline Inspection Robots

Background:: Robots for pipeline inspection are frequently employed in long-distance oil, wastewater, and natural gas pipelines. Much complex research is being conductedon pipeline inspection robots, including work on fluid-driven and non-fluid-driven, among other things. Research on pipeline inspection robots can be advanced by examining their current stage of development. Additionally, pipeline inspection robots may be able to promote the growth of the pipeline transportation sector by creating new structures. Objective:: This study aims to examine the benefits and drawbacks of several pipeline inspection robots and theirdevelopment trend through the lens of the most recent advancements in the field. Methods:: Through the structure and application scenarios of the latest representative patents of pipeline inspection robots, the working principle and characteristics of pipeline inspection robots are demonstrated. Results:: The shortcomings of the current pipeline inspection robots are highlighted, along with potential future development pathways and research issues, by comparing pipeline inspection robots of various structures. Conclusion:: The development of pipeline inspection robots has benefited the construction of sewage, oil, natural gas, and long-distance pipelines, as well as long-distance pipeline transportation. Because of these robots' unique features and ample room for advancement, pipeline inspection robots have even more development prospects.

Overview of Health-Monitoring Technology for Long-Distance Transportation Pipeline and Progress in DAS Technology Application.

There are various health issues associated with the different stages of long-distance pipeline transportation. These issues pose potential risks to environmental pollution, resource waste, and the safety of human life and property. It is essential to have real-time knowledge of the overall health status of pipelines throughout their entire lifecycle. This article investigates various health-monitoring technologies for long-distance pipelines, providing references for addressing potential safety issues that may arise during long-term transportation. This review summarizes the factors and characteristics that affect pipeline health from the perspective of pipeline structure health. It introduces the principles of major pipeline health-monitoring technologies and their respective advantages and disadvantages. The review also focuses on the application of Distributed Acoustic Sensing (DAS) technology, specifically time and space continuous monitoring technology, in the field of pipeline structure health monitoring. This paper discusses the process of commercialization development of DAS technology, the main research progress in the experimental field, and the open research issues. DAS technology has broad application prospects in the field of long-distance transportation pipeline health monitoring.

A knowledge-enhanced graph-based temporal-spatial network for natural gas consumption prediction

The accurate prediction of natural gas consumption plays a central role in long-distance pipeline system production and transportation planning, and it becomes even more important during present political situation. The existing prediction methods for natural gas consumption barely consider spatial correlations and domain knowledge. As a result, the study proposes a novel deep learning prediction method (knowledge-enhanced graph-based temporal-spatial network, abbreviated to KE-GB-TSN) for predicting natural gas consumption by integrating domain knowledge into association graph construction and capturing temporal-spatial features via a hybrid deep learning network. This study first applies the domain knowledge that analyses the operation technique of the natural gas pipeline network and combines the historical data to establish an association graph. Subsequently, the historical data and association graphs are input to a hybrid deep learning network to predict natural gas consumption. The comparative experiments are conducted by taking real-world cases of natural gas consumption as examples. At last, a sensitivity analysis of different components combination is carried out to exhibit the significance of each component in the proposed model. The results prove that the proposed model is capable of achieving more accurate and efficient predicted results compared to the advanced models, such as decision trees and gated recurrent units. The Mean Absolute Relative Errors and Root Mean Squared Relative Errors gotten by the proposed model are less than 0.11 and 0.14 in all cases, indicating an improvement compared to previous works. Additionally, it is also suggested that domain knowledge and temporal-spatial correlations are crucial for the excellent performance of the prediction model.

Analysis of influencing factors of pneumatic flow enhancement of pumped concrete based on discrete element method

It is known that, long-distance concrete pipeline transportation often causes pipe blocking accidents. For the problem of pipeline blockage, we have invented a swirl speed-increasing device. In this study, the discrete element method was used to calibrate the parameters of the contact model through the slump bucket experiment, and a discrete element model of horizontal pumping concrete was established. Based on the particle unit, the flow-promoting mechanism of the swirl speed-increasing device was studied, and the effects of the pumping speed, the volume fraction of coarse aggregate and the wind speed output of the device on the movement state of the particles and the flow-promoting distance were analyzed. The results show that the maximum velocity and flow-promoting distance of the particle unit increase with the increase of pumping speed and wind speed, and decrease with the increase of the coarse aggregate volume fraction. When the pumping speed and wind speed are large, the installation distance of the flow promoting device should be increased. When the volume fraction of concrete aggregate is large, the installation distance of the flow promoting device should be shortened. Our swirl speed-increasing device can solve the problem of pumping concrete pipeline blockage. The discrete element model of pumping concrete established in this study can well reflect the motion state of the concrete unit in the pipeline, which verifies the applicability of the discrete element model. The numerical simulation conclusion in this paper can avoid system energy waste and pipeline blockage caused by improper selection of device installation spacing.

Influence of mine water on corrosion of Long-Distance coal pipeline transportation in hongliulin coal mine

In order to improve the economic efficiency of coal transportation in Shenwei pipeline and reduce the investment cost. According to the location characteristics of Shenmu head end pulping plant, it is convenient to take hongliulin mine water, and it can be considered as the second water source. This paper mainly compares the changes of water quality indexes before and after Fugu water and hongliulin mine water are used as coal handling water, and analyzes the influencing factors of corrosion and scaling tendency, so as to provide theoretical guidance and suggestions for the later optimization of coal handling water. The analysis shows that the water quality of Fugu water and hongliulin mine is weakly alkaline, and the ion content before and after pulping is relatively low, which has little impact on the corrosion. However, several key factors such as conductivity and Cl- content should be considered when studying the corrosion of the pipeline during long-term operation.

Influence of mine water on corrosion of Long-Distance coal pipeline transportation in hongliulin coal mine

In order to improve the economic efficiency of coal transportation in Shenwei pipeline and reduce the investment cost. According to the location characteristics of Shenmu head end pulping plant, it is convenient to take hongliulin mine water, and it can be considered as the second water source. This paper mainly compares the changes of water quality indexes before and after Fugu water and hongliulin mine water are used as coal handling water, and analyzes the influencing factors of corrosion and scaling tendency, so as to provide theoretical guidance and suggestions for the later optimization of coal handling water. The analysis shows that the water quality of Fugu water and hongliulin mine is weakly alkaline, and the ion content before and after pulping is relatively low, which has little impact on the corrosion. However, several key factors such as conductivity and Cl- content should be considered when studying the corrosion of the pipeline during long-term operation.

Combined EIS and BAS-BP neural network analysis of electrochemical corrosion on pipeline steel in silty soil in a Salt–Temperature coupling environment

Soil corrosion negatively affects long-distance pipeline transportation. Studies on this phenomenon have revealed the potential safety risks associated with metal durability. In previous studies on the soil corrosion of pipeline steel, corrosion behaviour, which is influenced by the salt–temperature coupling environment, was seldom considered. In this study, a laboratory-simulated corrosion environment for electrochemical impedance spectroscopy (EIS) measurements was designed to analyse the corrosion behaviour of X80 steel immersed in silty soil mixed with different concentrations of NaCl and Na2SO4 over a temperature range of 20 to −20 °C. Nyquist plots displayed three capacitive reactance arcs in various soil environments in the range of 100 kHz to 0.1 Hz. Furthermore, an equivalent circuit model was utilised to fit the Nyquist and Bode plots. The effects of the Cl− concentration, SO42− concentration, and temperature on the EIS characteristics were analysed. The change in the temperature considerably affected the degree of corrosion. Cl− reacted with the metal and catalysed the corrosion process, whereas SO42− enhanced the chemical inertness of the metal surface. The mechanism of the metal corrosion reaction was revealed by performing scanning electron microscopy and X-ray photoelectron spectroscopy. Based on the experimental results and beetle antennae search (BAS) algorithm, an optimised back propagation (BP) neural network model was established to predict the Nyquist plot of the soil corrosion process. The predicted Nyquist plots exhibited the same electrochemical characteristics as those shown by the experimental curves. A comparison of the evaluation parameters revealed that the equivalent circuit of the corrosion system can be applied to the prediction results obtained from the BAS-BP neural network model. Moreover, it demonstrated the practicality of the neural network prediction method in the field of corrosion science.

Organophosphate tri- and diesters in source water supply and drinking water treatment systems of a metropolitan city in China.

The water contaminations with organophosphate triesters (tri-OPEs) and diesters (di-OPEs) have recently provoked concern. However, the distributions of these compounds in natural water sources and artificial water treatment facilities are poorly characterized. A comprehensive study was therefore performed to measure their concentrations in a water source, a long-distance water pipeline, and a drinking water treatment plant (DWTP). Eight tri-OPEs and 3 di-OPEs were found to be widely distributed, with total concentrations in source water and pipelines ranging from 290.6 to 843.9ng/L. The most abundant pollutants were tris(1-chloro-2-propyl) phosphate (TCPP), triethyl phosphate, tri-n-butyl phosphate (TnBP), and diphenyl phosphate (DPhP). Di-OPEs appeared to be removed less efficiently in the DWTP than the parent tri-OPEs, and the elimination efficiencies of tri-OPEs were structure-dependent. Long-distance pipeline transportation had no significant effect on the distributions of tri- and di-OPEs. Statistical analysis suggested that the sources of di-OPEs and the corresponding tri-OPEs differed, as did those of DPhP and di-n-butyl phosphate. A risk analysis indicated that tri-OPEs present limited ecological risks that are mainly due to TnBP and TCPP, and that the human health risks of tri-OPEs are negligible. However, di-OPEs (especially DPhP) may increase these risks. Further studies on the risks posed by di-OPEs in aquatic environments are therefore needed.

An Improved Composite Fly Ash Gel to Extinguish Underground Coal Fire in Close Distance Coal Seams: A Case Study

Fire extinguishing with the superior performance of fly ash composite colloid material is a cost‐effective colloid fire prevention technology. In this paper, a new powder additive (suspending agent (XK‐XJ) and gelling agent) was developed for the existing fire extinguishing technology of fly ash compound colloid. Tests show that the best additions to the fly ash slurry were 0.3% and 0.1∼0.3%, respectively. The grouting technical scheme of adding a suspending agent on the ground and gelling agent downhole was proposed to solve the problems of solid material settlement and blockage in the long‐distance pipeline transportation process. Finally, the optimized fly ash colloid fire prevention and extinguishing technology was successfully applied to the fire control engineering examples of close‐range coal seam groups, and the rationality of the developed powder and its proportion was tested, and the feasibility in coal fire control was tested.

Research and existing problems of pour point depressant/viscosity reducer for crude oil production

The composition and structure of pour point depressant/viscosity reducer for pipeline transportation and its application effect in long-distance pipeline transportation in China as well as the application effect of oil-soluble viscosity reducer and water-soluble viscosity reducer for wellbore lift in low-viscosity and high-viscosity heavy oil wells in China are introduced. The main technical problems existing in the study of viscosity reducer for heavy oil formations drive are presented.

STAMP-based causal analysis of China-Donghuang oil transportation pipeline leakage and explosion accident

The methods used by researchers and accident investigators to analyze or investigate accidents are critical for understanding the underlying causes and for proposing improvement measures. As a systematic analysis model, Systems-Theoretic Accident Model and Processes (STAMP) is used in the aviation, maritime, and railway transportation industries, among others. To the best of the author's knowledge, no systematic analysis approach has been applied in the long-distance pipeline transportation industry. However, the pipeline transportation system is increasingly being considered a complex socio-technical system that requires the exploration of accident causes from a systematic viewpoint. The aims of this paper are to identify the causal factors of the China-Donghuang oil transportation pipeline leakage and explosion accident through a systematic method and illustrate the appropriateness of applying STAMP to the analysis of incidents in the long-distance pipeline transportation industry. To achieve this, a systematic analysis based on STAMP is conducted on the China-Donghuang oil transportation pipeline leakage and explosion accident. The analysis results expand the causal analysis beyond immediate failures, to causes from a systematic perspective, and illustrate the utility of applying the STAMP model to the pipeline transportation domain.

Paste-like Pumping Backfilling Technique with High Stowing Gradient and Long Distance

In order to achieve the maximum recovery of the shallow residual ore resources in Xikuangshan Mine Flash Star Antimony Ltd. in Hunan province of China, on the premise of safe mining, a new paste-like pumping backfilling technique characterized by long-distance pipeline transportation and a high stowing gradient (the ratio of the whole length to the vertical height of the filling pipeline) was studied through the proportion test, pumpability experiment, system process design and reliability analysis of the backfilling system. It is revealed that the optimum proportions (cement: fly-ash: tailings) applied in the stope and mined-out gobs are 1:2:8 and 1:4:15, respectively with mass fractions both being 74%-76% and the rheological property both being paste-like. Furthermore, the backfill pump HBT80/21-220S has been proved to meet the requirements of the backfill industry. The cost of the backfill system is 23.46 yuan per ton, and the remnant ore recovery rate is 60%. In the end, the output value increased by 2.322 billion yuan. The remarkable economic benefits indicate that the application of horizontal sand silos is feasible. As this backfilling technique sets a precedent in China, it can not only enrich the backfilling theories but also provide some constructive guidance for environmental protection and mining in mines with similar conditions.

Simulation of long-distance pipeline transportation properties of whole-tailings paste with high sliming

Based on Bingham rheological model, a three-dimensional numerical simulation model for long-distance pipeline transportation is established by computational fluid dynamics (CFD) to study the pipeline transportation properties of high sliming paste from a copper mine in China. Based on the rheological properties test, the pressure and velocity of pipeline and elbow are simulated by CFD under different mass concentrations and different stowing capacities. The results show that the pipeline resistance of whole-tailings paste with high sliming while without pumping agent is much higher than that with high sliming and pumping agent at the same mass concentration, and the pipeline resistance of whole-tailings paste with high sliming while without pumping agent is much higher than that with low sliming while without pumping agent. It is very important to add pumping agent to whole-tailings paste with high sliming, and the resistance changes with mass concentration and stowing capacity at the same cement-to-sand ratio of 1:5 and tailings-to-waste ratio of 6:1. However, the change is just limited, that is to say, the paste transportation system is of good stability. Furthermore, at the elbow, the maximum pressure and velocity transfer to the outside of the pipe from the inside. However, lubricating layer is formed at the pipe wall because of high content of fine particles in whole-tailings paste, which will protect the elbow from abrasion. CFD provides an intuitive and accurate basis for pipeline transportation study, and would have a wider application space in the study of paste rheological properties and resistance reduction methods.

Time-Varying Hydraulic Gradient Model of Paste-Like Tailings in Long-Distance Pipeline Transportation

Paste-like tailings slurry (PTLS) is always simplified as a Bingham plastic fluid, leading to excessive computational errors in the calculation of the hydraulic gradient. In the case of paste-like tailings in long-distance pipeline transportation, to explore a high-precision and reliable hydraulic gradient formula, the rheological behavior of paste-like tailings slurry was analyzed, a time-varying hydraulic gradient model was constructed, and a series of laboratory shear tests were conducted. The results indicate that the PTLS shows noticeable shear-thinning characteristics in constant shear tests; the calculated hydraulic gradient declined by about 56%, from 4.44 MPa·km−1 to 1.95 MPa·km−1 within 253 s, and remained constant for the next four hours during the pipeline transportation. Comparing with the balance hydraulic gradient obtained in a semi-industrial loop test, the computational errors of those calculated by using the time-varying hydraulic gradient model, Jinchuan formula, and Shanxi formula are 15%, 78%, and 130%, respectively. Therefore, our model is a feasible and high-precision solution for the calculation of the hydraulic gradient of paste-like tailings in long-distance pipeline transportation.

Refinery continuous-time crude scheduling with consideration of long-distance pipeline transportation

In reality, crudes from unloading storage tanks at a docking berth may experience long-distance pipeline transportation to refinery charging tanks before their processing by crude distillation units. Such pipeline transportations cause significant transport delay and crude holdup that will substantially affect plant production performance. Unfortunately, current short-term crude scheduling studies have never systematically considered these issues. In this work, a new continuous-time crude scheduling model has been developed, which addresses the long-distance pipeline transportation and other realistic considerations such as brine settling and multiple jetties for crude unloading. The feeding of crudes into pipeline, and crude movements inside pipeline, as well as crude discharging to the receiving charging tanks are combined with the continuous time formulation of crude scheduling. The efficacy of the developed scheduling model has been demonstrated by three case studies including one industrial size example. An outer-approximation (OA) based iterative algorithm (Karuppiah et al., 2008) is implemented to successfully solve the case studies.

Research on numerical simulation and protection of transient process in long-distance slurry transportation pipelines

The calculation of water-hammer pressure phenomenon of single-phase liquid is already more mature for a pipeline of uniform characteristics, but less research has addressed the calculation of slurry water hammer pressure in complex pipelines with slurry flows carrying solid particles. In this paper, based on the developments of slurry pipelines at home and abroad, the fundamental principle and method of numerical simulation of transient processes are presented, and several boundary conditions are given. Through the numerical simulation and analysis of transient processes of a practical engineering of long-distance slurry transportation pipeline system, effective protection measures and operating suggestions are presented. A model for calculating the water impact of solid and fluid phases is established based on a practical engineering of long-distance slurry pipeline transportation system. After performing a numerical simulation of the transient process, analyzing and comparing the results, effective protection measures and operating advice are recommended, which has guiding significance to the design and operating management of practical engineering of longdistance slurry pipeline transportation system.

Measurement of Bulk Modulus and Study of its Impact on Transport Characteristics for Dense Paste

Dense paste is solid-liquid waste from industry production and sewage disposal process with high concentration and viscosity. It has large output, low utility rate and serious environmental pollution. While the engineering application of long-distance and large-diameter pipeline transportation solve the disposal of dense paste, the serious back-flow causes that actual throughput is far less than the theoretical. It is relevant to dense paste bulk modulus, which there has no related study. In this paper, we carried out a test on coal slime based on wave speed method theory. We get the bulk modulus by measuring the propagation speed of pressure wave in the pipe, and analyze its impact on actual throughput and effective stroke of piston.Verification shows that the scheme is feasible and provides reference for the further study between bulk modulus and transport characteristics.

A New Technique of Low-Pressure Long-Distance Soft Clay Pipeline Transportation

A new technique of long-distance pipeline transportation of soft clay, which is related to Non Newton--Bingham pipe flow studies. Propose a method of non-continuous pneumatic conveying method with surface film lubrication, which will obviously reduce the friction between pipe wall and mud column and the Viscous resistance of clay. The air is injected to form air-column between mud columns. Adjust the lengths of mud column and air column and their proportion, and make the pushing force bigger than or near equivalent to the resistant force, until the optimum air-mud ratio for the required delivery distance is achieved. Long distance transportation of soft clay through low pressure pipeline is achieved. The method, with the features of energy-saving, high efficiency, profitable, can be applied in fields of water conservancy, petroleum, chemical, mining, and environmental protection, etc.

Life Cycle Inventories for the Nuclear and Natural Gas Energy Systems, and Examples of Uncertainty Analysis (14 pp)

The energy systems included in the ecoinvent database v1.1 describe the situation around year 2000 of Swiss and Western European power plants and boilers with the associated energy chains. The addressed nuclear systems concern Light Water Reactors (LWR) with mix of open and closed fuel cycles. The system model ‘Natural Gas’ describes production, distribution, and combustion of natural gas. Comprehensive life cycle inventories of the energy systems were established and cumulative results calculated within the ecoinvent framework. Swiss conditions for the nuclear cycle were extrapolated to major nuclear countries. Long-term radon emissions from uranium mill tailings have been estimated with a simplified model. Average natural gas power plants were analysed for different countries considering specific import/export of the gas, with seven production regions separately assessed. Uncertainties have been estimated quantitatively. Different radioactive emission species and wastes are produced from different steps of the nuclear cycle. Emissions of greenhouse gases from the nuclear cycle are mostly from the upstream chain, and the total is small and decreasing with increasing share of centrifuge enrichment. The results for natural gas show the importance of transport and low pressure distribution network for the methane emissions, whereas energy is mostly invested for production and long-distance pipeline transportation. Because of significant differences in power plant efficiencies and gas supply, country specific averages differ greatly. The inventory describes average worldwide supply of nuclear fuel and average nuclear reactors in Western Europe. Although the model for nuclear waste management was extrapolated from Swiss conditions, the ranges obtained for cumulative results can represent the average in Europe. Emissions per kWh electricity are distributed very differently over the natural gas chain for different species. Modern combined cycle plants show better performance for several burdens like cumulative greenhouse gas emissions compared to average plants. Comparison of country-specific LWRs or LWR types on the basis of these results is not recommended. Specific issues on different strategies for the nuclear fuel cycle or location-specific characteristics would require extension of analysis. Results of the gas chain should not be directly applied to areas other than those modelled because emission factors and energy requirements may differ significantly. A future update of inventory data should reconsider production and transport from Russia, as it is a major producer and exporter to Europe. The calculated ranges of uncertainty factors in ecoinvent provide useful information but they are more indications of uncertainties rather than strict 95% intervals, and should therefore be applied carefully.