Processes, Volume 11, Issue 8 (August 2023) – 286 articles

Peanuts, being crucial crops of global importance, have gained widespread recognition for their versatility and nutritional value. In addition to direct consumption, either with or without treatment, peanuts can be the subject of diverse applications focusing mainly on two distinct objectives: oil extraction and defatting processes. As a result of the first process, a solid matrix is generated as a by-product, necessitating the exploration of strategies for its valorization, while the second process is centered on obtaining protein-rich, low-fat peanuts, for which the oil recovered becomes the by-product. As consumers increasingly seek out plant-based foods for their potential health benefits, this trend is expected to persist, encompassing peanut-based foods as well. This review elucidates the methods used for extracting peanut oil, including mechanical and chemical processes that have been combined with biological or physical pre-treatment techniques. Their primary goals are to maximize oil extraction and unlock the untapped potential of defatted whole peanuts. Additionally, the review addresses the challenges and opportunities in both oil extraction and defatting processes, emphasizing the importance of sustainable practices and efficient resource utilization. The advantages and disadvantages of each method were also evaluated and critically analyzed. Developing novel methods for potential industrial applications and limiting the drawbacks associated with traditional methods became necessary. A comparison in terms of productivity, efficacy, specificity, quality of the extracts, and operating conditions was conducted, which favored the novel methods as being mostly environmentally friendly and cost-efficient. Full article

Research on the flow electrification characteristic is of paramount importance for ensuring the electrostatic safety of liquid hydrogen transportation systems. However, the discussion about electrostatic saturation in flow electrification has been lacking. To address this gap, a theoretical model governing the process of flow electrification is constructed which couples the charge conservation equation with the Navier-Stokes equations and applies the Neumann boundary conditions at the solid-liquid interface, and the application of this model is validated by existing experimental data with the simulation parameters of A_t and n being 9.08 × 10¹² and 0.85 for liquid hydrogen. A comparison with benzene reveals that benzene almost reaches the electrostatic saturation state after flowing one meter, whereas the flow of liquid hydrogen remains in the linear growth stage. However, with an increase in pipe length, a gradual saturation trend emerges in the curves of streaming current versus flow distance when the flow distance exceeds 10 m. At the outlet, the corresponding streaming current and charge density are approximately 160 pA and 3 μC/m³, respectively, significantly higher than those observed at one-meter flow distance. Furthermore, the influences of pipe radius and flow velocity on the arrival of electrostatic saturation are analyzed, and the results show that increasing both the pipe radius and flow velocity leads to a delay in the arrival of electrostatic saturation and enhances the saturation value of the streaming current. In conclusion, this study thoroughly discusses the development of flow electrification along with the flow distance and the phenomenon of electrostatic saturation in the long-distance flow of liquid hydrogen, which is crucial for the safe transportation of liquid hydrogen over extended distances. Full article

Severe erosion phenomena often occur in industrial polycrystalline silicon units, leading to hydrogen leakage accidents and affecting long-term operation. It is favorable to use a computational fluid dynamics (CFD) simulation with the dense discrete phase model (DDPM) and the sub-grid energy-minimization multi-scale (EMMS) drag model to improve the prediction accuracy of complex multiphase erosion phenomena in a connecting pipe of an industrial polycrystalline silicon unit. Furthermore, the effect of droplet the specularity coefficient on boundary conditions is thoroughly considered. The predicted erosion behaviors are consistent with industrial data. The effects of operations parameters were discussed with three-dimensional CFD simulation, including droplet size and hydrogen volume fraction on erosion behaviors. The results indicated that the non-uniform multiphase erosion flow behavior near the wall can be simulated accurately with the EMMS drag model in a coarse mesh. A suitable droplet specularity coefficient such as 0.5 can also improve the accuracy of erosion position. Small liquid droplets, such as those of 30 μm size, will follow the gas phase better and have a lower erosion rate. The inertia effect of large droplets, such as those of 150 μm size, plays a dominant role, resulting in obvious erosion on the elbow walls. The erosion range and thinning rate enlarge with the increase in hydrogen volume fraction. A few silicon solid particles, such as 0.01% volume fraction, change local flow behaviors and probably cause the variation of local erosion positions. The process of erosion deformation first circumferentially extended and then accelerated at the local center position deeper. Full article

The development of natural fractures (NFs) in shale gas reservoirs is conducive to improving the productivity of shale gas wells. However, NF development leads to high-frequency frac hits between the infill and parent wells, which critically restricts its efficiency. To elucidate the large contribution of hydraulic fractures (HFs) and NFs in frac hits during the production and the development of NF-developed shale gas reservoirs, such reservoirs in the WY area of western China are taken as an example. A total of 197 frac hits well events in this area are systematically classified via the frac-hit discrimination method, and the effects of different factors on HF- and NF- dominated frac hits are classified and studied. Combined with the correlation analysis method and the chart method, the main controlling factors affecting the two types of frac hits are determined, and the corresponding frac-hit prevention countermeasures are proposed. The research demonstrates that (1) the distribution and development of NFs are crucial to production after frac hits. NFs and HFs in the WY area cause 51% and 49%, respectively, of the frac hits. (2) The main controlling factors in NF-dominated frac hits are the approximation angle, fracture linear density, and horizontal stress difference, whereas they are net pressure in fractures, horizontal stress difference, and liquid strength in HF-dominated frac hits. Sensitivity analysis shows that the NF activation difficulty coefficient fluctuates between −35.1% and 47.6%, and the maximum hydraulic fracture length fluctuates between −43.5% and 25.29%. (3) The corresponding frac-hit prevention countermeasures are proposed for the two types of formation mechanisms from different approaches, including frac-hit risk assessment and path planning, production well pressurization and stress diversion, and infill-well fracturing parameter optimization. This paper not only provides a reference for exploring the formation mechanism of frac hits in fractured shale gas reservoirs but also a theoretical basis for the corresponding frac-hit prevention countermeasures. Full article

To address the issues of strong subjectivity, low efficiency, and difficulty in on-site model deployment encountered in existing CCTV defect detection of pipelines, this article proposes an object detection model based on an improved YOLOv5s algorithm. Firstly, involution modules and GSConv simplified models are introduced into the backbone network and feature fusion network, respectively, to enhance the detection accuracy. Secondly, a CBAM attention mechanism is integrated to improve the detection accuracy of overlapping targets in complex backgrounds. Finally, knowledge distillation is performed on the improved model to further enhance its accuracy. Experimental results demonstrate that the improved YOLOv5s achieved an [email protected] of 80.5%, which is a 2.4% increase over the baseline, and reduces the parameter and computation volume by 30.1% and 29.4%, respectively, with a detection speed of 75 FPS. This method offers good detection accuracy and robustness while ensuring real-time detection and can be employed in the on-site detection process of sewer pipeline defects. Full article

Vacuum freeze-dried products exhibit properties characteristic of porous media, rendering them superior in both drying and rehydration capabilities. However, the process of sublimation drying is constrained by its substantial time and energy costs. To comprehensively grasp its technological process and identify the optimal process parameters, the cellular automata method was employed for sublimation process simulation. Carrot slices, measuring 10 mm in thickness and 40 mm in radius, were selected for both simulation and experimentation. The sublimation process was characterized using a two-dimensional heat and mass transfer equation, inclusive of a dusty gas model. Additionally, a cellular automaton model was applied to simulate the mass transfer process, temperature, and moisture content changes in the sublimation drying stage. Then, the accuracy of the model was verified through experimentation. There was a remarkable alignment between simulation and experimental outcomes, with determination coefficients R2 of 99.4% for moisture content and 97.6% for temperature variations. Full article

The present work is a numerical analysis of electro-thermo convection, occurring in a square differentially heated cavity filled with a dielectric fluid. The cavity experiences the combined effects of viscous, electrical, and thermal forces. The equations modelling the physical problem are solved via the finite volume approach. The study focuses on the effect of cavity tilt on the fluid flow structure and thermal performance inside the enclosure under the action of an electric field. A parametric study was performed, where the tilt angle is getting varied between 0° and 90°, as well as the Rayleigh number (5000 ≤ Ra ≤ 250,000) and the electric field (0 ≤ T ≤ 800). Furthermore, the electric charge injection level C, the mobility M and the Prandtl Pr numbers were all adjusted to a value of 10. The obtained results demonstrate that the hydrodynamic and thermal fields are significantly impacted by the cavity inclination. In addition, regardless of the thermal Rayleigh’s number, high electric field values could govern fluid movement through electric forces. Electro-convection typically demonstrates an oscillating flow due to the tilting of the cavity which gives rise to a bicellular regime occupying the entire cavity. A correlation has been established to estimate heat transfer by considering various system parameters such as cavity inclination, electrical Rayleigh number, and thermal Rayleigh number. Full article

This paper presents a comprehensive computational fluid dynamics (CFD) model for describing the oxidative coupling of methane (OCM) carried out in fixed-bed reactors for olefin production. Initially, a single pellet model was developed and implemented to describe the heat and mass transfer within the pellet and between the gaseous and solid phases. Subsequently, sensitivity analyses were performed to assess the impact of pellet arrangement and feed conditions on the heat and mass transfer rates, subsequently affecting concentration and temperature profiles. As indicated by the simulations, a high ethylene content could be obtained with the increase in the ${\mathrm{CH}}_4/{\mathrm{O}}_2$ ratio, aligning well with previous experimental studies. Furthermore, it was observed that pellet arrangement can significantly affect the reactor performance. Additionally, the behavior of temperature and concentration in the gaseous and solid phases can be very different, such that pseudo-homogeneous modeling approaches should not be assumed a priori. Finally, the simulated temperature differences between the gaseous and solid phases were very substantial and above 100 °C, indicating the occurrence of catalyst auto-ignition behavior. Full article

Carbon dioxide (CO₂) is widely used in the prevention and control of spontaneous coal combustion. In this manuscript, three low-rank coals with different metamorphic degrees were selected as the research objects. The temperature-programmed experiments, in situ infrared cooling experiments, simulation of the competitive adsorption of CO₂ and oxygen (O₂) in coal pores, and simulation study of the CO₂ inhibition of the coal oxygen composite reaction were used to obtain the role and effect of CO₂ in preventing oxygen adsorption in coal at the low-temperature oxidation stage. It was concluded that CO₂ can displace the O₂ near the pore wall to physically prevent the adsorption of O₂. Through the changing law of heating rate and a kinetics analysis, it was found that CO₂ can increase its activation energy by 5.3–108.3% during the slow heating stage of coal and reduce its heat rate. At around 120 °C, coal loses the protective effect of CO₂. From the changes in functional groups, it can be seen that when coal was cooled in the CO₂ atmosphere, mainly pyrolysis and condensation reactions occurred due to the lack of O₂. In addition, CO₂ can also inhibit the chain reaction of the chemical adsorption of oxygen in coal. This work provides a theoretical basis for CO₂ prevention and the control of spontaneous coal combustion. Full article

Pecan (Carya illinoinensis) nuts are rich in functional compounds (unsaturated fatty acids, phytosterols, polyphenols, and tocopherols) associated with various health benefits. Commercially, pecan nuts are roasted to enhance their physical, chemical, and sensory properties. In the present study, response surface methodology (RSM) was used to optimise the quality and nutritional and antioxidant attributes of ‘Wichita’ pecan nuts roasted by using a microwave process with a range of microwave power (96.45–803.55 W) and roasting time (1.37–5.62 min). The microwave-roasted pecan nuts were analysed for hardness, total colour difference (TCD), and radical scavenging activity and modelled using the central composite design. The results showed that microwave power and roasting time significantly (p < 0.05) influenced the quality attributes of the pecan. The quadratic model adequately described the changes in TCD and hardness, respectively, while the 2FI model adequately described the changes in DPPH radical scavenging activity. To obtain the desired pecan nuts quality attributes (TCD = 1863.391; hardness = 28.755 N and DPPH radical scavenging activity = 33.877 mmol Trolox/g), the determined conditions were 700 W and 2.24 min, with a desirability of 0.557. The primary unsaturated fatty acids, including cis-oleic, cis-linoleic, α-linolenic, and stearic acids, were not affected (p < 0.05) by microwave roasting the pecan nuts at determined conditions. Volatile compounds, such as alcohols, aldehydes, ketones, lactones, hydrocarbons, and carboxylic acids, were identified in both raw and microwave-roasted pecan nuts, with limonene, which possesses various health properties, being the major volatile compound. It can be concluded that microwave roasting may be optimised using response surface methodology to produce quality pecan nuts that can be used as snacks or as an ingredient in other snack products. Full article

The multi-stage pulse competition of pressurized pulsed water jet becomes the initial pulse at the head tip, and hydraulic parameters are the key parameters that affect the characteristics of multiple pulses. Based on the ultra-high-speed imaging system, a pressurized pulsed water jet flow field capture system was constructed, and the effects of initial pressure and driving pressure of the pressurized chamber on the characteristics of multi-stage pulses were studied. The experimental results show that as the initial pressure of the booster chamber increases, the jet changes from a discontinuous state to a continuous state, and the multi-level pulse simultaneously changes from dominant multi-pulse to implicit multi-pulse; as the driving pressure increases, the initial spacing between the first pulse and the second pulse increases, and the peak velocity of the initial pulse gradually increases. At the same time, the location of the peak velocity also shifts away from the nozzle as the driving pressure increases. In addition, the peak velocity of the initial pulse is relatively close to the theoretical velocity of the continuous jet under driving pressure conditions. Full article

This work focuses on developing and applying Encrypted Lyapunov-based Model Predictive Control (LMPC) in a nonlinear chemical process network for Ethylbenzene production. The network, governed by a nonlinear dynamic model, comprises two continuously stirred tank reactors that are connected in series and is simulated using Aspen Plus Dynamics. For enhancing system cybersecurity, the Paillier cryptosystem is employed for encryption–decryption operations in the communication channels between the sensor–controller and controller–actuator, establishing a secure network infrastructure. Cryptosystems generally require integer inputs, necessitating a quantization parameter d, for quantization of real-valued signals. We utilize the quantization parameter to quantize process measurements and control inputs before encryption. Through closed-loop simulations under the encrypted LMPC scheme, where the LMPC uses a first-principles nonlinear dynamical model, we examine the effect of the quantization parameter on the performance of the controller and the overall encryption to control the input calculation time. We illustrate that the impact of quantization can outweigh those of plant/model mismatch, showcasing this phenomenon through the implementation of a first-principles-based LMPC on an Aspen Plus Dynamics process model. Based on the findings, we propose a strategy to mitigate the quantization effect on controller performance while maintaining a manageable computational burden on the control input calculation time. Full article

Aiming at the stability of the output speed and the poor adaptability of the transmission system during the operation of a cotton picker, a control strategy of hydro-mechanical continuously variable transmission (HMCVT) for cotton pickers based on gray prediction and fuzzy PID is proposed. Firstly, the hardware and software of the existing hydraulic mechanical coupling transmission test-bed of cotton pickers are designed, and the HMCVT human-computer interaction measurement and control system is built by using LABVIEW 2020 software. Then, combined with the transmission theory, the control strategy and gray prediction model are designed. Finally, the continuity test, transmission efficiency test, and adaptive control verification test are carried out. The results show that as the input speed increases, the peak time of the pump motor output speed is prolonged, while the overall speed regulation process is smoother, and the output speed process of the HMCVT system is continuous. As the displacement ratio of the variable pump increases, the transmission efficiency of the hydraulic system increases accordingly, but the highest efficiency is around 0.8. At a working speed of 10 km/h, the transmission efficiency of the HMCVT system of the cotton picker is more than 80%, and the high efficiency of the mechanical system in the whole system makes up for the low efficiency of the hydraulic system, and the transmission efficiency of the cotton picker is the highest at 15–25 km/h. The speed under the adaptive control strategy is better, with good robustness to sudden torque changes and speed fluctuations in the range of ±0.0125% under external load conditions. This study provides a reference for future adaptive control of transmission output speed for heavy-duty vehicles and construction machinery. Full article

The process of energy transition in Colombia has sparked an exploration into appropriate geographical areas for the utilization of solar energy. The country’s rugged terrain and significant climate variability pose challenges for implementing standardized technologies uniformly across all regions. Consequently, this study aims to develop and apply a mathematical model to characterize the performance of a solar adsorption cooling system under the environmental conditions found in six distinct Colombian cities, taking into account different thermal profiles and extreme weather periods such as the El Niño and La Niña phenomena. The selected mathematical model was simulated in these cities, considering ambient temperature and solar radiation variables over a twelve-month period during these extreme weather phenomena and an additional twelve-month period representative of a typical year with minimal influence from these phenomena. The results indicated that despite a lower coefficient of performance (COP) compared to the other cities, Riohacha demonstrated a greater number of ice production days owing to its high levels of solar radiation. Full article

Improving the resolution and accuracy of the mechanical properties of organic-rich shale is very important. The results can reveal the mechanical properties of shale from micro scale and serve as a guide for the design of hydraulic fracture optimization parameters. This study introduced an advanced technique to obtain the mechanical properties of shale with high resolution (58.6 nm/pixel) by combining SEM, EDS, and Atomic Force Microscopy (AFM). To locate the target area in SEM and AFM accurately, a positioning technique that uses special distributions of pyrite was established. AFM PeakForce QNM mode was selected due to its advantages at capturing topography and mechanical properties in material. Results illustrated the ability of AFM to obtain the mechanical properties (modulus) of individual mineral components in shale, the detailed topography of crack, and mechanical properties of minerals in a specific area. In particular, the mechanical properties of minerals around crack explained the layered distribution of minerals around the fractures, and the cracks developed in the clay mineral layer was detected. This article demonstrates the great potential application of AFM in shale. Full article

Rockfall disasters have long restricted the further improvement of the safety level of steeply dipping coal seams (SDCSs). When a rockfall disaster occurs, it causes damage to the hydraulic support and other equipment at the working face. An effective way to carry out protection design is using the law of rockfall migration and energy evolution. Therefore, this study used the polyhedral rockfall migration and its impact process on the hydraulic support equipment of the working face as the research object and analyzed the influence of relevant parameters on the maximum contact deformation, maximum impact force, and energy absorption of the column during the collision and contact between the rockfall and the hydraulic support column. Firstly, with hexahedral rockfall as an example, the migration process of rockfall was simulated using PFC3D software. Secondly, according to the Hertz contact theory, the contact model of the shock process between the rockfall and the hydraulic support column was constructed, and the maximum deformation and maximum impact force of the collision contact between the rockfall and the column were obtained. Finally, the Hamilton principle and the Galerkin discrete method were used to construct the dynamic model of the collision between the rockfall and the column, and the energy evolution law of the shock process between the rockfall and the column was studied. The conclusions of this paper can provide a certain theoretical basis for the prediction of rockfall disasters and the design of rockfall protection devices. Full article

Adsorbents presenting high adsorption capacity, fast adsorption rate, easy regeneration, and a good possibility for reusability are ideal for removing 4-chloro-2-methyl-phenoxyacetic acid (MCPA) or other pesticides from wastewater. Here, the effects of regeneration treatments on adsorption–desorption cycles are examined using two commercial activated carbons (ACs) (Merck and Norit 1240 X). MCPA adsorption was fast on Merck and Norit ACs in powder form (6 h) but on Norit AC, in granular form, adsorption was too slow, and the equilibrium time was reached only after 288 h. MCPA adsorption kinetic data were analyzed by applying pseudo-first-order, pseudo-second-order, and Weber–Morris models. The pseudo-second-order model fit better to all data, and the Weber–Morris representation allows confirming that on Norit 1240 X, in granular form, the pore diffusion was the limiting factor concerning the MCPA adsorption. Merck and Norit 1240 X (in powder and granular form) ACs loaded with MCPA were submitted to different regeneration process by washing with distilled water, ethanol, HNO₃, and NaOH solutions and washed with NaOH solutions or ethanol followed by a thermal treatment. The ACs regenerated with ethanol performed well in the subsequent adsorption–desorption cycles. All ACs had more than 99% desorbed MCPA after the first cycle of washing with ethanol. The washing with NaOH solution was less efficient. The regeneration process, consisting of washing the sample with a solution of NaOH and subsequent heating at 573 K, was very effective. After this regeneration procedure, the amount of MCPA adsorbed on Norit 1240 X AC was even higher than the amount adsorbed in the first adsorption cycle. At present, washing methods for adsorbent regeneration are not used at an industrial level. However, research for environmentally friendly regeneration methods is necessary to achieve the objectives of the circular economy. Full article

Separating heavy components from natural gas not only enhances safety, improves pipeline transportation, ensures product quality, and addresses environmental considerations, but it also exerts an influence on global energy trends. Therefore, separating heavy components is necessary and can result in beneficial goods. This article presents a comprehensive study on the process simulation and optimization of the recovery of natural gas condensate via the combined refrigeration of a mixture of ethane and propane as a refrigerant. The optimization objectives include maximizing the recovery of ethane and propane, minimizing energy consumption, and achieving desired product quality targets. A sensitivity analysis was performed to assess the impact of key parameters on process performance. Using Aspen HYSYS software, the influence of the cooler outlet stream temperature and expander outlet stream pressure on the shaft power and profit of a dry gas compressor was analyzed based on the operating conditions of the case plant, which has a processing capacity of 2988 kmol/h. The profitability of the plant is at a maximum when the cooler’s outlet stream temperature is −61 °C and the expander’s outlet stream pressure is 2500 kPa. After optimization, the refrigeration cycle system can reduce the plant’s energy consumption by 1516.4 kW. An optimized process design can lead to enhanced recovery efficiency, reduced energy consumption, and improved profitability in the natural gas industry. Full article

With the progress of society and the iterative improvement of infrastructure construction, the power grid transmission lines have also entered an era of intelligence. The national distribution system has made ensuring the regular operation of the distribution network as well as prompting troubleshooting and detection its top priority. Research on fault diagnosis for 35 kV single-ended radial distribution networks is still in its infancy compared to other hot topics in the industry, such as short-circuit fault detection and fault node localization. This study adopts the 35 kV single-ended radial distribution network as a model, detects fault lines via the traveling wave method, and accurately locates fault nodes using the wavelet conversion method, hoping to quickly identify and locate fault nodes in distribution networks. The experimental results demonstrate that the research method can quickly identify the faulty line and carry out further fault node location detection. The final obtained fault distance is 1.19 km with an actual error of only 0.16 km; the maximum relative errors are only 0.33 km and 0.21 km when the initial phase angle and transition resistance parameters are changed, respectively; and the error amplitude fluctuations are essentially stable. The experimental results also demonstrate that the research method can quickly identify the faulty line and carry out further fault node location. Full article

This research proposes the dandelion optimizer (DO), a bioinspired stochastic optimization technique, as a solution for achieving maximum power point tracking (MPPT) in photovoltaic (PV) arrays under partial shading (PS) conditions. In such scenarios, the overall power output of the PV array is adversely affected, with shaded cells generating less power and consuming power themselves, resulting in reduced efficiency and local hotspots. While bypass diodes can be employed to mitigate these effects by redirecting current around shaded cells, they may cause multiple peaks, making MPPT challenging. Therefore, metaheuristic algorithms are suggested to effectively optimize power output and handle multiple peaks. The DO algorithm draws inspiration from the long-distance movement of a dandelion seed, which relies on the force of the wind. By utilizing this bioinspired approach, the DO algorithm can successfully capture the maximum power point (MPP) under different partial shading scenarios, where traditional MPPT algorithms often struggle. An essential contribution of this research lies in the examination of the performance of the proposed algorithm through simulation and real-time hardware-in-the-loop (HIL) results. Comparing the DO algorithm with the state-of-the-art algorithms, including particle swarm optimization (PSO) and cuckoo search (CS), the DO algorithm outperforms them in terms of power tracking efficiency, tracking duration, and the maximum power tracked. Based on the real-time HIL results, the DO algorithm achieves the highest average efficiency at 99.60%, surpassing CS at 96.46% and PSO at 94.74%. These findings demonstrate the effectiveness of the DO algorithm in enhancing the performance of MPPT in PV arrays, particularly in challenging partial shading conditions. Full article

Emergency management synergy capability is not only a “touchstone” to measure the operation effect of the emergency system of coal mine enterprises, it is an important symbol to reflect its level. In order to improve the level of emergency management in coal mines based on the PPRR theory of crisis management cycle, in this paper a hierarchical evaluation index system is constructed based on the emergency management process. A quantitative evaluation model of emergency synergy capacity is proposes based on the entropy–weighted elemental topology method to conduct evaluation and model validation for the case of J coal mine in Henan Province. The results show that the overall evaluation of the emergency management synergy capability of J Coal Mine is at a “good” level, with the emergency prevention synergy capability, emergency preparedness synergy capability, and recovery and reconstruction synergy capability at a “good” level and the emergency response synergy capability is at a “average” level. This indicates that the evaluation model is consistent with the current development of coal mining enterprises and has universal applicability. Therefore, this research can provide decision-making support for emergency management synergistic capacity building of coal mining enterprises to enhance the inherent driving force behind the early completion of the dual carbon task in the coal mining industry. Full article

The production of building materials is unavoidable if the well-being and development of society are to be maintained. However, in manufacturing these materials, significant greenhouse gas emissions and environmental effects are produced. For this reason, and with the aim of reducing the impact of the manufacture of these materials, this work developed a geopolymeric material made up solely of wastes, brick dust and biomass bottom ashes which replaced the traditional ceramic materials. To evaluate the quality of this sustainable geopolymeric material, different groups of specimens were formed with different percentages of both residues, subsequently determining the physical properties of the new-formed geopolymers and guaranteeing they accomplish the prescriptions of the ceramic regulations for construction. In addition, the results of the geopolymer characterisation tests were statistically analysed using factor analysis, with the sole purpose of establishing connections and interdependence between the variables that influence the geopolymerisation process. Thus, it was possible to demonstrate that the combination of brick dust and biomass bottom ashes produced geopolymers with adequate qualities to replace traditional ceramics, as well as that the different combinations of both residues produced feasible materials to be used as ceramics with various characteristics, with two main factors determined by factorial analysis that governed the physical properties of the geopolymer obtained: the percentage of brick dust and the theoretical porosity. Full article

This study aims at exploring earthworm protein hydrolysate and its peptide fractions as a potential hypoglycemic agent by inhibiting α-amylase and α-glucosidase. Firstly, the best hydrolysis conditions to gain the hydrolysates with the highest α-amylase inhibitory activity (α-AIA) and α-glucosidase inhibitory activity (α-GIA) were figured out using a one-factor test. Next, the stability of the hypoglycemic activity of the hydrolysates and their 5 peptide fractions recovered using ultrafiltration membranes were assessed by employing the tests of in vitro digestion, thermal, and pH treatment. The results showed that at the best hydrolysis conditions, the hydrolysates exhibited α-AIA of 91.30 ± 2.51% and α-GIA of 44.69 ± 0.47%. Specifically, the <1 kDa peptide fraction from the hydrolysate expressed a greater α-AIA than that of acarbose, with nearly the same α-GIA as that of voglibose. The α-AIA and α-GIA of the hydrolysates and their fractions were enhanced after the in vitro digestion treatment, whereas they remained over 40% after the pH treatment in the range of 1 to 11 or heat treatment at 100 °C for 180 min. These data provide the preliminary evidence to develop the earthworm protein hydrolysate and its peptide fractions in functional food or nutraceutical products with hypoglycemic activity. Full article

The olefin separation from their mixture with paraffins by facilitated transport membranes is a very important process for the further macromolecular compounds production. Membranes loaded with silver ions, which are responsible for the facilitated olefin transport, are instable with time due to their reduction, while those containing protons catalyze the polymerization of olefins. In this work, membranes based on polyethylene with grafted sulfonated polystyrene in various ionic forms (H⁺, Li⁺, Na⁺) were used for the first time for the separation of the ethylene/ethane mixture. The influence of sulfonation time, relative humidity, and various ionic forms on ethylene separation was studied. The SEM study shows a non-uniform sulfur distribution over the membrane thickness for membranes sulfonated for different reaction times. With increasing sulfonation time and relative humidity the ethylene permeability and the factor of its separation with ethane increase. Separation factors for membranes in the Li⁺-form are shown to be as high as for membranes in the H⁺-form. A possible mechanism for the facilitated ethylene transport is discussed. Full article

This paper focuses on a comprehensive stability study of a two-area power system with wind power integration and synthetic inertia control in each area, considering the effects of varying the interconnection link. Normally, synthetic inertia proposals are analyzed in one-area systems, in which stability is tested without considering transmission system phenomena, such as coherency. As modern power systems are progressively becoming interconnected, the possibility of forming two or more non-coherent areas is likely, which poses a challenge to synthetic inertia control techniques that use system frequency as a main feedback signal. In this context, this work addresses a crucial gap in the existing literature and provides a valuable starting point for studying more complex interconnected power systems with wind power integration. Simulations were performed in Matlab-Simulink considering a data-driven frequency dynamics model of the Chilean Electric System, and a wind power model with synthetic inertia control $H_2$ norm minimization in each area. The results showed that it is possible to find local optimal feedback gains, preserving the stability of the global system under significant variations in the interconnection link. RoCoF and Nadir indicators are provided, highlighting the benefits of synthetic inertia control, particularly in low-inertia situations. Full article

Two kinds of slit pore carbon materials, namely activated carbon (AC) and 3D graphene materials (3D-GS), were purchased to examine their methane storage capabilities. The structural analysis and characterization of AC and 3D-GS were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), the X-ray energy dispersive spectrum (EDS), and N₂ adsorption/desorption isotherms. Additionally, a thermodynamic framework was employed in the Henry’s law region to evaluate the potential well between the adsorbed fluid and adsorbent. The adsorption behavior of methane on two materials at room temperature and high pressure was also investigated. The results show that the Toth equation is the most suitable model for predicting adsorption isotherms than the Langmuir and L-F equations and determines that the absolute uptake of methane storage on AC and 3D-GS are, respectively, 7.86 mmol·g⁻¹ and 8.9 mmol·g⁻¹ at 298 K and 35 bar. In the Henry’s law region, the isosteric heat of methane adsorption on 3D-GS is larger than that of AC. Meanwhile, the potential well between methane and carbon-based materials decreases as the temperature increases. This indicates that the capacity of methane uptake is enhanced at lower temperatures, which is consistent with the measurements of adsorption isotherms. The research concludes that the 3D-GS is more suitable as a material storage medium than AC. This study provides valuable theoretical guidance for exploring the potential of methane storage on slit pore carbon-based material. Full article

This article proposes an innovative two-stage technology for biomass torrefaction generating high-quality biochar, more specifically biocoal, as solid fuel, and offering a promising solution to the challenges posed by the combustion of biomass. In particular, the higher quality of biochar as solid fuel reduces the build-up of unmanageable deposits on fired surfaces, as these deposits inhibit heat transfer and reduce the efficiency of biomass boilers. The proposed two-stage technology involves torrefaction in a hearth-type reactor at temperatures up to 250 °C, followed by a subsequent stage of cooling achieved through washing with water. The two-stage torrefaction technology is integrated within a vertical hearth reactor vessel composed of three superimposed trays serving for biomass input, torrefaction, and water washing combined with biomass cooling, respectively. Upon contact with torrefied biomass, cooling water turned into water vapor; hence, eliminating the requirement for subsequent biomass separation and drying. The system was tested on sunflower husk, and results showed a reduction in the content of problematic elements such as alkali metal chlorides or sulfur compounds in biochar ash, suggesting lower corrosion rates of convective heating surfaces of the boiler under ash sediments. It is hypothesized that, while water exited hot biomass in the form of water vapor instead of liquid water, as is typically the case in water-washing processes, a share of undesirable elements may still have been removed from biomass through vaporization, without necessitating any additional process for ash removal. Hence, the index values calculated according to the chemical analysis of biomass ash suggested that sunflower husk biochar (biocoal) resulting from the proposed two-stage torrefaction process may display fuel characteristics similar to biomasses whose combustion ash may form reduced levels of deposits on boiler surfaces. Therefore, the proposed technology holds the potential to improve solid fuel characteristics of biomass, targeting enhanced efficiency and sustainability of biomass-fired power plants. Full article

Rapid-cycle pressure swing adsorption (PSA) with small adsorbents particles is intended to improve mass transfer rate and productivity. However, the mass transfer mechanisms are changed with reduction of particle size during rapid-cycle adsorption process. A heat and mass transfer model of rapid-cycle PSA air separation process employing small LiLSX zeolite particles is developed and experimentally validated to numerically analyze the effects of mass transfer resistances on the characteristics of cyclic adsorption process. Multicomponent Langmuir model and linear driving force model are employed for characterizing the adsorption equilibrium and kinetic. The results of numerical analysis demonstrate that the dominant mass transfer resistance of small adsorbents particles is a combination of film resistance, axial dispersion effect and macropore diffusion resistance. The oxygen purity, recovery and productivity of the product are overestimated by ~2–4% when the effect of axial dispersion on mass transfer is ignored. As particle size decreases, the front of nitrogen-adsorbed concentration and gas temperature become sharp, which effectively improves the performance. However, the adverse effect of axial dispersion on the mass transfer becomes significant at very small particles conditions. It is nearly identical shapes of nitrogen concentration and gas temperature profiles after adsorption and desorption steps. The profiles are pushed forward near the production end with an increase in bed porosities. The optimal oxygen recovery and productivity are achieved with a particle diameter of 0.45 mm and bed porosity of 0.39 during the PSA process. Full article

Aiming at the optimal layout of a deep chamber for coal–gangue separation (DCCS) based on the weak stratum horizon, an in-depth study was carried out by combining field investigations, model tests, and numerical simulations. Firstly, the main structural characteristics of DCCS were summarized. Then, the deformation and failure law for rocks surrounding DCCS were revealed under different horizons in the weak stratum. Finally, the optimal layout methods of DCCS based on the thickness and horizon in the weak stratum were determined in different in situ stresses, using the proposed comprehensive evaluation method for surrounding-rock stability. The results show that if the thickness of the weak stratum was small, the side near the roof of DCCS should be arranged along the weak stratum when the lateral pressure coefficient was λ < 0.6 or λ > 1. The side near the floor of DCCS was arranged along the weak stratum when 0.6 ≤ λ ≤ 1 and the surrounding-rock stability was the best. If the thickness of the weak stratum was large, the side of DCCS should be arranged along the weak stratum when λ < 0.6 or λ > 1. The floor of DCCS was arranged along the weak stratum when 0.6 ≤ λ ≤ 1, which was most favorable for the surrounding-rock control. The research results have important guiding significance for the spatial layout and support design of DCCS. Full article

The Lower Permian Fengcheng formation is a significant source of rocks and a reservoir for the Mahu Sag in the Junggar Basin. Recently, the paleo-environment deposition factors of the P₁f formation have become a popular research topic. This research was conducted using data from the F7 well of Mahu Sag, based on the geochemical analysis results of TOC (total organic carbon), REE (rare earth elements), and major and trace elements of 53 samples from P₁f (Lower Permian Fengcheng formation), and some deposition factors are discussed. The P₁f deposition process was classified into four stages based on paleo-environment elemental indicators. This research describes the deposition process of the evolution of alkaline lakes. The early and preliminary stages of alkali lake evolution are considered as late P₁f₁ to middle P₁f₂; the paleoclimate of this process was dry, the reduction conditions increased, and the paleo-productivity and lake salinity were enhanced. The terminal stage of alkali lake evolution is considered as late P₁f₂ to middle P₁f₃; in this period, the paleoclimate changed with seasonal cycles, resulting in a decrease in water salinity and an increase in oxidation; the paleo-productivity of the alkaline lake was at a medium level. Until the end of P₁f₃, the salinity of the lake decreased, and the water body became anoxic and weakly alkaline. Furthermore, the research on TOC and sedimentary parameters confirmed that the deposition of P₁f organic matter is affected by multiple types of factors. A relatively warm climate, lack of oxygen, fresh water–brackish water, suitable debris flow, and high primary productivity conditions promoted organic matter deposition. Full article