Browse
Recent Submissions
New records verified within the last 240 days
Showing records 371 to 395 of 767. [First] Page: 1 12 13 14 15 16 17 18 19 20 Last
Investigation into the Perforation Optimization in Conglomerate Reservoir Based on a Field Test
Qinghu Fan, Yonggui Ma, Junping Wang, Liang Chen, Zhiquan Ye, Yajun Xu, Huan Li, Bo Wang
September 21, 2023 (v1)
Keywords: conglomerate reservoir, field test, hydraulic fracturing, perforation scheme
The Mahu conglomerate reservoir is characterized by strong heterogeneity and the uneven stimulation of the horizontal lateral during hydraulic fracturing. The optimization of the perforation number per cluster is of great value for horizontal well multi-stage fracturing (HWMF) because the suitable perforation number not only promotes the uniform propagation of multiple fractures but also prevents excessive perforation erosion. In this work, a typical well in the Mahu conglomerate reservoir was selected, and a field test of optimizing the perforation number was carried out. The perforation schemes of three, five, and eight perforations per cluster were designed in nine fracturing stages, respectively. The wellhead pressure under different perforation schemes was compared and analyzed with the step-down flow rate test, and the optimal perforation number per cluster in the Mahu conglomerate reservoir was selected as eight. The theoretical calculation results show that eight perforations p... [more]
Thermal Treatment of Commercial Sweetener Solutions Modulates the Metabolic Responses in C57BL/6 Mice during a 24-Week-Long Exposition
Elizabeth Nieto-Mazzocco, Elena Franco-Robles, Adriana Saldaña-Robles, Neith Pacheco, César Ozuna
September 21, 2023 (v1)
Subject: Biosystems
Keywords: caloric sweeteners, non-caloric sweeteners, orexigenic and anorexigenic peptides, oxidative damage
The purpose of this paper was to evaluate the effect of thermal treatment (TT: 121 ± 2 °C, 15 min) on the composition of commercial sweeteners diluted in water (10 °Brix). Additionally, we evaluated the impact of this TT on metabolic responses in C57BL/6 mice during a 24-week treatment. The sweeteners included in this study were sucrose (SC), glucose-63 (GLU63), agave syrup (AS), sucralose (SUC), and steviol glycosides (STG). HPLC analysis showed changes in the concentration of simple sugars of GLU63 and AS after TT. Importantly, in all sweeteners, TT modulated metabolic responses in mice. The mice drinking thermally treated sweetener solution showed an increase of 10−13% (p < 0.05) in food intake (AS, SUC, and STG), beverage intake (2−21%; SC and GLU63), weight gain (38%; SUC), energy (10−13%; AS, SUC, and STG), glucose levels (11−17%; SC and STG), GLP-1 (30%; SC) and insulin (88%; AS) release, and the generation of protein carbonyl (SC) and malondialdehyde (all sweeteners tested)... [more]
Natural Convection in a Circular Enclosure with Four Cylinders under Magnetic Field: Application to Heat Exchanger
Raouia Azzouz, Mohamed Bechir Ben Hamida
September 21, 2023 (v1)
Keywords: circular enclosure, cylinders, magnetic field, natural convection, Nusselt number
This paper documents the 2D numerical study of magnetohydrodynamic unsteady natural convective heat transfer in a circular enclosure with four heating cylinders in both the horizontal and the vertical mid-plane. The fluid is an incompressible Newtonian fluid. The main transport equations based on the conservation of mass, momentum, and energy are calculated and solved using a finite element numerical solver with the following parameter ranges: dimensionless distance between cylinders S = 0.05−0.29, Rayleigh number Ra=103−106, and Hartmann number for Ha = 0−120. COMSOL Multiphysics, a numerical simulation program, was used to solve the governing equations. It was demonstrated that for lower Ra values, heat transfer through an applied magnetic field is unaffected for a specific S value because the mechanism of transport is diffusion, whereas for larger Ra, there is a complex interaction among magnetic field and physical thermal properties. The features of the heat transfer rate are deter... [more]
Nanofluids as a Waste Heat Recovery Medium: A Critical Review and Guidelines for Future Research and Use
José Pereira, Ana Moita, António Moreira
September 21, 2023 (v1)
Subject: Materials
Keywords: nanofluids, organic Rankine cycle, thermoelectric generator, waste heat conversion, waste heat recovery, waste to energy
The thermal energy storage and conversion process possesses high energy losses in the form of waste heat. The losses associated with energy conversion achieve almost 90% of the worldwide energy supply, and approximately half of these losses are waste heat. Hence, waste heat recovery approaches intend to recuperate that large amount of wasted heat from chimneys, vehicles, and solar energy systems, among others. The novel class of thermal fluids designated by nanofluids has a high potential to be employed in waste heat recovery. It has already been demonstrated that nanofluids enhance energy recovery efficiency by more than 20%. Also, the use of nanofluids can improve the energy capacity of steelworks systems by around three times. In general, nanofluids can improve efficiency and reduce exergy destruction and carbon emissions in devices like heat exchangers. The current work summarizes the application of nanofluids in waste heat recovery and discusses the involved feasibility factors. A... [more]
Analysis of the Fuel Properties of the Seed Shell of the Neem Plant (Azadirachta indica)
Francisco Simão Neto, Maria Melo Neta, Ana Sousa, Luana Damasceno, Bruna Sousa, Samuel Medeiros, Rafael Melo, Ada Lopes, José Santos, Maria Rios
September 21, 2023 (v1)
Subject: Materials
Keywords: alternative source, bioenergy, Neem, plant biomass, proximate analysis, TG, XRF
The energetic potential of the seed shell of the Neem plant (Azadirachta indica) was investigated using proximate analysis, Higher Heating Value (HHV), thermal analysis (TG-DTG and DSC) in inert and oxidative atmospheres, and X-ray fluorescence (XRF). The results of ash (3.80% ± 0.44), volatile matter (81.76% ± 1.30), fixed carbon (14.44% ± 1.74), and estimated HHV (18.791 MJ/kg: average value) are compatible with other biomasses already used as fuels in the bioenergy industry. Thermograms showed three main degradation events in synthetic air and two in nitrogen, attributed to the moisture, release of volatile materials, and decomposition of hemicellulose, cellulose, and lignin. The elements positively detected by the XRF were Ca, K, S, P, Fe, Ti, Zn, Rb, and Sr.
Optimization Study of Inert Gas Distribution for Multiple-Bay Fuel Tank
Lei Shao, Jiawei He, Xia Lu, Weihua Liu
September 21, 2023 (v1)
Subject: Optimization
Keywords: inerting system, optimization scheme, TOPSIS method, ventilation mode
Inert gas distribution has a great influence on the inerting effect, especially for the multiple-bay fuel tank. In order to find out the optimal scheme, an optimization method based on the entropy-weight improvement TOPSIS method is proposed, and an experimental system of inert gas distribution is established to measure the speed index and uniformity index. The results show that the position of the inlet and outlet has a significant effect on the overall inerting effect. The inerting scheme designed by the entropy-weight improvement TOPSIS method can not only reduce the flow demand of inert gas but also make the oxygen distribution more uniform. The optimization inerting scheme of the Boeing 747 aircraft has improved the average speed index by 3.01% and the average uniformity index by 26.18%. The smoke visualization experiment also showed that the scheme designed by the entropy-weight improvement TOPSIS method has the denser white smoke, which means that the scheme has better performan... [more]
Bearing Fault Diagnosis Based on ICEEMDAN Deep Learning Network
Bo Liang, Wuwei Feng
September 21, 2023 (v1)
Keywords: convolutional block attention module, deep learning, deep residual network, Hilbert, ICEEMDAN, rolling bearing fault diagnosis
Bearing fault diagnosis has evolved from machine learning to deep learning, addressing the issues of performance degradation in deep learning networks and the potential loss of key feature information. This paper proposes a fault diagnosis method for rolling bearing faults based on ICEEMDAN combined with the Hilbert transform (ICEEMDAN-Hilbert) and a residual network (ResNet). Firstly, the collected fault vibration signals are classified as fault samples and randomly sampled with a fixed length. The IMF components obtained by decomposing the bearing fault vibration signals using ICEEMDAN are able to maximize the restoration of fault vibrations. Then, the IMF components are transformed from one-dimensional time-domain signals to two-dimensional time-frequency domain images using Hilbert transformation. The RGB color images can be directly used in deep learning models without the need for manual labeling of a large amount of data, thereby avoiding the loss of key feature information. The... [more]
Effect of Self-Recirculating Casing Treatment on the Aerodynamic Performance of Ultra-High-Pressure-Ratio Centrifugal Compressors
Tengbo Fan, Baotong Wang, Chuanxiang Yan, Wenchao Zhang, Zhaoyun Song, Xinqian Zheng
September 21, 2023 (v1)
Keywords: aerodynamic stability, centrifugal compressor, multi-splitter blade, parametric model, self-recirculating casing treatment, ultra-high pressure ratio
The motivation to design a more efficient and compact aircraft engine leads to a continuous increase in overall pressure ratio and decrease in the stage number in compressors. Compared to the traditional multi-stage compressor, a single-stage ultra-high-pressure-ratio centrifugal compressor with a pressure ratio higher than 10.0 can significantly improve the engine’s power-to-weight ratio and fuel economy with a reduced structure complexity. Thus, it has great potential to be adopted in the compression system of advanced aero engines, such as turboshaft engines, in the future. However, the highly narrow Stable Flow Range (SFR) of ultra-high-pressure-ratio centrifugal compressors is a severe restriction for engineering applications. This research focuses on the aerodynamic performance of a ultra-high-pressure-ratio centrifugal compressor, and three-dimensional simulation is employed to investigate the effect of Self-Recirculating Casing Treatment (SRCT) on the performance and stability... [more]
Numerical Study on High Throughput and High Solid Particle Separation in Deterministic Lateral Displacement Microarrays
Maike S. Wullenweber, Jonathan Kottmeier, Ingo Kampen, Andreas Dietzel, Arno Kwade
September 21, 2023 (v1)
Keywords: Computational Fluid Dynamics, deterministic lateral displacement, discrete element method, high throughput, immersed boundary method, particle concentration, particle separation
Deterministic lateral displacement (DLD) is a high-resolution passive microfluidic separation method for separating micron-scale particles according to their size. Optimizing these microsystems for larger throughputs and particle concentrations is of interest for industrial applications. This study evaluates the limitations of the functionality of the DLD separation principle under these specific conditions. For this reason, different particle volume fractions (up to 11%) and volumetric flow rates (corresponding to Reynolds numbers up to 50) were varied within the DLD microsystem and tested in different combinations. Resolved two-way coupled computational fluid dynamics/discrete element method (CFD-DEM) simulations including spherical particles were performed. The results show a general increase in the critical diameter with increasing volume fraction and decreasing separation efficiency. The largest tested Reynolds number (Re = 50) results in the highest separation efficiency, particu... [more]
A Study on the Mechanism of Casing Deformation and Its Control Strategies in Shale Oil Hydraulic Fracturing
Nan Zhang, Peng Wang, Junliang Li, Wenhai Ma, Xiaochuan Zhang, Hongtao Zhang, Chenggang Jiang, Weiming Huang, Xinzhu Feng, Shuwei Liu
September 21, 2023 (v1)
Keywords: casing deformation, fracture slip, hydraulic fracturing, prevention of casing deformation, shale oil
The problem of casing deformation caused by large-scale hydraulic fracturing in shale oil wells severely restricts the efficient development of Gulong shale oil. In order to clarify the mechanism of casing deformation in shale oil wells, comprehensive analysis was conducted on engineering factors, multi-arm caliper logging, seismic attributes, and the distribution characteristics of casing deformations. This study shows that casing strength, cementing quality, and wellbore curvature are not the main controlling factors for casing deformation. Casing deformation is caused by the communication between hydraulic fractures and natural fractures during the fracturing process, which increases the fluid pressure in the natural fracture and induces shear slip, resulting in casing deformation due to shear stress. Based on the understanding of the mechanism of casing deformation in shale oil wells, two targeted casing deformation prevention and control methods are proposed. First, temporary plug... [more]
Evaluation of Fracture Volume and Complexity of Tight Oil Wells Based on Flowback Data
Jie Li, Sen Liu, Jianmin Li, Zhigang Liu, Xi Chen, Jiayan Li, Tianbo Liang
September 21, 2023 (v1)
Keywords: flowback analysis, hydraulic fracturing, stimulation volume, tight oil
For tight reservoirs, horizontal wells and multi-stage fracturing can generate a complex fracture network that realizes economic and effective development. The volume and complexity of the fracture network are of great significance to accurately predicting the productivity of tight oil wells. In this work, a mathematical model of a multiphase flow is proposed to evaluate the stimulation effect based on the early flowback data. The model showing the early slope of the material balance time (MBT) and production balance pressure (RNP) can help estimate the effective stimulated volume of the horizontal well. The linear flow region can be determined from the slope of the log−log plot of the MBT versus RNP curve, which equals 1. The method is verified by commercial simulation software, and the calculated stimulated volume is consistent with the statistical results of simulation results. Results also show that the flow pattern of the fracture−matrix system can be judged by the slope of the fl... [more]
Fused Data-Driven Approach for Early Warning Method of Abnormal Conditions in Chemical Process
Xiaomiao Song, Fabo Yin, Dongfeng Zhao
September 21, 2023 (v1)
Keywords: abnormal conditions, chemical process, data-driven
The utilization of data-driven methods in chemical process modeling has been extensively acknowledged due to their effectiveness. However, with the increasing complexity and variability of chemical processes, predicting and warning of anomalous conditions have become challenging. Extracting valuable features and constructing relevant warning models are critical problems that require resolution. This research proposed a novel fused method that integrates K-means density-based spatial clustering of applications with noise (DBSCAN) clustering and bi-directional long short-term memory multilayer perceptron (Bi-LSTM-MLP) to enable early warning of abnormal conditions in chemical processes. The paper applied the proposed method to analyze the early warning using actual process data from Eastman Tennessee and the atmospheric pressure reduction unit as an example. In the TE model and example, the root mean square error (RMSE) of this method is 0.006855 and 0.052546, respectively, which is quit... [more]
Advancement in Microbial Fuel Cells Technology by Using Waste Extract as an Organic Substrate to Produce Energy with Metal Removal
Ghada Mohamed Aleid, Anoud Saud Alshammari, Alamri Rahmah Dhahawi Ahmad, Fida Hussain, Sang-Eun Oh, Akil Ahmad, Mohamad Nasir Mohamad Ibrahim, Khalid Umar
September 21, 2023 (v1)
Subject: Biosystems
Keywords: Energy, heavy metals, microbial fuel cell, organic substrate, Wastewater
Energy generation using microbial fuel cells (MFC) and removing toxic metal ions is a potentially exciting new field of study as it has recently attracted a lot of interest in the scientific community. However, MFC technology is facing several challenges, including electron production and transportation. Therefore, the present work focuses on enhancing electron generation by extracting sugarcane waste. MFC was successfully operated in a batch mode for 79 days in the presence of 250 mg/L Pb2+ and Hg2+ ions. Sugarcane extract was regularly fed to it without interruption. On day 38, the maximum current density and power density were recorded, which were 86.84 mA/m2 and 3.89 mW/m2, respectively. The electrochemical data show that a sufficient voltage generation and biofilm formation produce gradually. The specific capacitance was found to be 11 × 10−4 F/g on day 79, indicating the steady growth of biofilm. On the other hand, Pb2+ and Hg2+ removal efficiencies were found to be 82% and 74.85... [more]
Study of Tangential Effusion Cooling of a Combustor Liner
Ziwan Li, Pengfu Xie, Qinghua Zeng, Xuanwu Chen
September 21, 2023 (v1)
Keywords: cooling efficiency, effusion cooling, heat and mass transfer, tangential inlet
Tangential effusion cooling of a combustor liner has a large difference from traditional effusion cooling on a plate. In this paper, numerical simulation is carried out to study the flow field, heat transfer characteristics and the factors affecting the cooling effectiveness of tangential effusion cooling of a combustor liner. It is found that the cooling film formed by the tangential jet is distributed in a divergent “horsetail” shape and adheres tightly to the inner wall of the liner, which increases the cooling area and effectiveness. Three different tangential inlet cooling hole arrangements and their cooling efficiencies are studied, and several important parameters that affect the cooling effectiveness are summarized. Then, an improved cooling hole arrangement is proposed, and its cooling efficiency is studied and compared with those of the original three arrangements. The results show that the new arrangement significantly improves the comprehensive cooling efficiency and decrea... [more]
Development of Ultrasound Piezoelectric Transducer-Based Measurement of the Piezoelectric Coefficient and Comparison with Existing Methods
Chandana Ravikumar, Vytautas Markevicius
September 21, 2023 (v1)
Keywords: acoustic method, dynamic, energy harvesting, interferometric, piezoelectric coefficient, quasi-static, ultrasound transducer
Energy harvesting using the piezoelectric material in the development of compact vibration energy harvesters can be used as a backup power source for wireless sensors or to fully replace the use of fossil-resource-wasting batteries and accumulators to power a device or sensor. Generally, the coefficient is used as the metric for evaluating the property in materials. Recent research reports that accurate measurement and calculation of the coefficient in materials, especially in polymers, can be challenging for various reasons. From the reviewed references, different methods, including the quasi-static, dynamic, interferometric, and acoustic methods, are discussed and compared based on the direct and indirect effect, accuracy, repeatability, frequency range, and so on. A development of an ultrasound piezoelectric transducer is conducted to estimate d33 coefficient with a reference value. The purpose of the method was mainly to measure the values of piezoelectric material in order to meas... [more]
Study on Enhanced Heat Transfer of the Convex Columns in the Cooling Channel of Motorized Spindle Based on Field Synergy
Yang Li, Zhe Nie, Dongxu Su, Jingyao Tian, Wenlei He, Wanhua Zhao
September 21, 2023 (v1)
Keywords: convex column, cooling channel, field synergy, motorized spindle
The cooling performance of motorized spindles plays an important role in accuracy in high-speed machining. Aiming at improving the cooling performance of traditional motorized spindles, convex columns were built in the cooling channel. Based on field synergy, the effects of quadrilateral, circular and triangular convex columns on the heat transfer performance of the cooling channel were analyzed numerically. We also compared the pressure drop between the inlet and outlet under the same conditions. The results show that the cooling channels with triangular convex columns provide the best cooling effect with the smallest increase in area compared to quadrilateral convex columns and circular convex columns. The pressure drop in the cooling channels with a circular convex column is minimized. By optimizing the spacing of the convex column, the best effect was found at a spacing of 7 mm. By optimizing the angle of the top angle of the triangular column, it is found that the enhanced heat tr... [more]
Atomic Force Microscopy as a Tool to Study Transport Phenomena in Biological Systems
Sneha Kandapal, Bingqian Xu
September 21, 2023 (v1)
Subject: Biosystems
Keywords: atomic force microscopy, binding interactions, biological systems, biomarkers, physical properties, transport
Biological interactions often involve the transport of molecules, ions, or other species across biological membranes or between interacting proteins. The understanding of these transport phenomena is crucial for the development of therapies for various diseases. Atomic force microscopy is a powerful tool that has been increasingly used to study biological systems at the nano scale. The high resolution, quantitative measurements, and the ability to probe biological interactions under near-physiological conditions make AFM an attractive tool for investigating transport phenomena in biological systems. In this article, we focus on the use of AFM in the study of the transport phenomena in biological systems. We discuss the principles of AFM, its instrumentation, and its application in the study of biomolecules and biological systems. We also provide a comprehensive overview of recent articles that have utilized AFM in the study of biomarkers in biological systems.
Experimental Study on the Influence of Wind Speed on the Start-Up Characteristics and Thermoelectric Generation Characteristics of Gravity Heat Pipe in Gangue Dump
Bailin Zhang, Shuhua Fang, Songlin Zhang, Runxu Zhang, Yu Zang
September 21, 2023 (v1)
Keywords: gravity heat pipe, start-up characteristic, thermoelectric generation, wind speed
As an efficient heat exchange component, the gravity heat pipe can effectively control the accumulated temperature inside gangue dumps and enable reuse of transferred heat. This study establishes a similar simulation experimental platform for gravity heat pipes to control gangue dumps and thermoelectric generation. The influence of wind speed on the start-up performance and isothermal performance of gravity heat pipes is analyzed, along with the impact of wind speed on their thermoelectric generation performance. Initially, the optimal working fluid height and heating height are determined, followed by a comparison and analysis of the isothermal performance, start-up performance, and thermoelectric generation performance of the gravity heat pipe under different wind speeds. The results indicate that at a wind speed of 1.0 m/s, the gravity heat pipe exhibits better start-up and isothermal performance. At a wind speed of 2.0 m/s, the thermoelectric power generation reaches its peak. In t... [more]
New Ultrasound-Assisted Extraction Sample Preparation Procedure for the Fast Determination of Total Sn in Canned Tomatoes by HG-ICP OES
Maja Welna, Anna Szymczycha-Madeja, Pawel Pohl
September 21, 2023 (v1)
Keywords: canned tomatoes, hydride generation, ICP OES, sample preparation, tin
An analytical method with no need for laborious sample preparation before determining the total Sn in canned tomatoes by hydride generation (HG) coupled to inductively coupled plasma optical emission spectrometry (ICP OES) was developed. The ultrasound-assisted extraction with various reagents (acidic media: HCl, HNO3, CH3COOH or aqua regia and alkaline: TMAH) that could replace the traditional wet sample digestion in the presence of a concentrated HNO3-H2O2 mixture was tested and compared. Tin hydride was generated directly from the prepared sample solution in the reaction with 1% NaBH4 or via prior acidification with a 1 mol L−1 HCl. The effect of the sample pretreatment before HG-ICP OES measurements on the Sn signal was also examined. The best results were obtained with aqua regia as the extraction medium, followed by a simple two-fold dilution of the sample extract combined with the addition of L-cysteine. The developed method was characterized by a detection limit of Sn at 0.74 n... [more]
Study on the Reservoir Heterogeneity of Different Volcanic Facies Based on Electrical Imaging Log in the Liaohe Eastern Sag
Zongli Liu, Huanping Wu, Shanyi Zhang, Xiaoqing Zhao
September 21, 2023 (v1)
Keywords: electrical imaging log, heterogeneity, porosity spectrum, volcanic facies
The volcanic rocks of the Es3 Formation (the third member of the Eocene Shahejie) in the Liaohe Eastern Sag can be divided into four facies and twelve subfacies. The porosity spectrum, porosity bin, variation coefficient (VC), and porosity width derived from electrical imaging log data were applied to study and characterize the heterogeneity of four facies and nine subfacies, both qualitatively and quantitatively. However, the VC and porosity width cannot be used to quantitatively classify heterogeneity when the VC is small and the porosity width is large. In the present study, the authors propose a new parameter, Pvcd = variation coefficient × porosity width. Based on this parameter, using a combination of porosity spectra, porosity bin features, VC, and porosity width, lithofacies heterogeneity is divided into three categories. The first is weak heterogeneity, which has a Pvcd < 1.1, a VC < 0.15, and a porosity width < 6. The second is moderate heterogeneity, which has a Pvcd 1... [more]
The Catalytic Upgrading Performance of NiSO4 and FeSO4 in the Case of Ashal’cha Heavy Oil Reservoir
Yasser I. I. Abdelsalam, Leysan A. Akhmetzyanova, Lilia Kh. Galiakhmetova, Gadel F. Baimukhametov, Rustam R. Davletshin, Aleksey V. Dengaev, Firdavs A. Aliev, Alexey V. Vakhin
September 21, 2023 (v1)
Keywords: aquathermolysis, catalytic hydrocracking, destructive hydrogenation, FeSO4, heavy oil, in situ upgrading, NiSO4, resins and asphaltenes, water-soluble catalysts
Aquathermolysis is a promising process for improving the quality of heavy oil under reservoir conditions. However, the application of catalysts during the process can significantly promote the transformation of the heavy fragments and heteroatom-containing compounds of crude oil mixtures into low-molecular-weight hydrocarbons. This research paper conducted a comparative analysis of the catalytic effectiveness of water-soluble metal salts like NiSO4 and FeSO4 in the process of aquathermolysis to upgrade heavy oil samples extracted from the Ashal’cha reservoir. The temperature of the experiment was 300 °C for a duration of 24 h. Compared to the viscosity of the native crude oil, the Fe nanoparticles contributed to a 60% reduction in viscosity. The viscosity alteration is explained by the chemical changes observed in the composition of heavy oil after catalytic (FeSO4) aquathermolysis, where the asphaltene and resin contents were altered by 7% and 17%, accordingly. Moreover, the observed... [more]
Improving Biomethanol Synthesis via the Addition of Extra Hydrogen to Biohydrogen Using a Reverse Water−Gas Shift Reaction Compared with Direct Methanol Synthesis
Kuntima Krekkeitsakul, Rujira Jitrwung, Weerawat Patthaveekongka, Teerasak Hudakorn
September 21, 2023 (v1)
Keywords: biohydrogen, biomethanol, catalytic conversion, molasses fermentation, reverse water–gas shift
Conventionally, methanol is derived from a petroleum base and natural gas, but biomethanol is obtained from biobased sources, which can provide a good alternative for commercial methanol synthesis. The fermentation of molasses to produce biomethanol via the production of biohydrogen (H2 and CO2) was studied. Molasses concentrations of 20, 30, or 40 g/L with the addition of 0, 0.01, or 0.1 g/L of trace elements (TEs) (NiCl2 and FeSO4·7H2O) were investigated, and the proper conditions were a 30 g/L molasses solution combined with 0.01 g/L of TEs. H2/CO2 ratios of 50/50% (v/v), 60/40% (v/v), and 70/30% (v/v) with a constant feed rate of 60 g/h for CO2 conversion via methanol synthesis (MS) and the reverse water−gas shift (RWGS) reaction were studied. MS at temperatures of 170, 200, and 230 °C with a Cu/ZnO/Al2O3 catalyst and pressure of 40 barg was studied. Increasing the H2/CO2 ratio increased the maximum methanol product rate, and the maximum H2/CO2 ratio of 70/30% (v/v) resulted in met... [more]
Coating Composites Based on Polyurea Elastomers with Increased Fire Resistance and Their Use as Roofing Systems
Wojciech Dukarski, Iwona Rykowska, Piotr Krzyżanowski, Joanna Paciorek-Sadowska, Marek Isbrandt
September 21, 2023 (v1)
Subject: Materials
Keywords: cone calorimetry, flame retardancy, polyurea, tensile strength, thermal properties
This paper presents the results of tests on elastomer coatings based on polyurea−polyurethane formulation with increased fire parameters. Coatings modified with flame retardants: bis(phenylphosphate) resorcinol (RDP), trischloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) were tested. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA/DTG) were used to investigate the structure and thermal stability. The effectiveness of resorcinol bis(phenylphosphate) (RDP), tris chloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) on heat release rate (HRR), smoke release rate (RSR), and oxygen consumption was evaluated using cone calorimetry. The cone calorimetry results were correlated with the mechanical properties of the coatings. The cone calorimetry analysis showed suitable organophosphorus flame retardant (FR) performance, significantly decreasing HRR and oxygen consumption. Additionally, 15% TCPP caused a reduction of HRR by over 50%, obtaining... [more]
Establishment and Application of a New Parameter Model for Quantitative Characterization of the Heterogeneity of Thick, Coarse-Grained Clastic Reservoirs: A Case Study of the Badaowan Formation in the Western Slope of the Mahu Depression, Junggar Basin, C
Boyu Zhou, Xiaodong Zhao, Xuebing Ji, Xinyu Wu, Wenping Zhao, Xi Rong
September 21, 2023 (v1)
Keywords: fluctuation coefficient, heterogeneity, Junggar Basin, Mahu Depression, thick coarse-grained clastic rock reservoir
The rock composition of thick-layer, coarse-grained clastic reservoirs is complex. There are large variations in granularity and poor selectivity. Reservoirs of thick-layer, coarse-grained clastic rocks are extremely heterogeneous. Current conventional parameters for quantitative characterization of reservoir heterogeneity, such as the calculation values of the permeability variation coefficient, the permeability rush coefficient, and the permeability contrast, are unbounded, have different representation angles, and the quantification degree of the characterization method is not high. This study takes the thick layer of the coarse-clastic rock reservoir developed in the western slope of the Badaowan Formation in the Mahu Depression of the Junggar Basin as an example. Through core observation, microscopic characteristics, and analysis of laboratory data, a new quantitative characterization parameter of heterogeneity is proposed, and a reservoir interpretation parameter model is establi... [more]
Evaluation of Foam Gel Compound Profile Control and Flooding Technology in Low-Permeability Reservoirs
Xiaoyu Gu, Gejun Cai, Xuandu Fan, Yanlong He, Feifei Huang, Zhendong Gao, Shaofei Kang
September 21, 2023 (v1)
Keywords: compound profile control and flooding, foam, gel, low permeability reservoir
In the waterflooding development of fractured ultra-low permeability reservoirs, the heterogeneity is becoming increasingly serious. The development of large fracture channels leads to serious water channelling and low recovery, and the effect of conventional profile control is not ideal. This paper proposed gel foam composite profile control and flooding technology to solve the above problems. Herein, the new intelligent gel and foaming agent systems were optimized through laboratory experiments, and their performance was evaluated. The new intelligent gel system has the characteristics of low viscosity, easy preparation, good injection, slow cross-linking, high strength, and long-term effectiveness. The injection parameters were optimized, and the indoor injection scheme was formulated, that is, the optimal injection volumes of gel and foam slugs were 0.3 and 0.6 PV, respectively. The injection sequence of composite slugs was to inject gel slugs first, then foam slugs. The injection... [more]
Showing records 371 to 395 of 767. [First] Page: 1 12 13 14 15 16 17 18 19 20 Last