As the regulations for the upgrading and transformation of wastewater treatment plants have become increasingly stringent, the process flow of wastewater treatment has gradually lengthened and become more complex. Addressing how to intelligently monitor operational conditions of process equipment and enhance fault management has emerged as a hot research topic due to the significant safety incidents and environmental pollution events that faults in wastewater treatment systems can cause. This paper starts by analyzing the characteristics of wastewater treatment process flows and the main types of faults. It comprehensively reviews the latest achievements and progress in fault detection and diagnosis in wastewater treatment processes both domestically and internationally. It summarizes three types of fault detection and diagnostic methods: model?based, domain experience?based, and data?driven approaches. The paper evaluates the current applications, strengths, and weaknesses of these wastewater treatment process fault detection and intelligent diagnostic methods, identifies existing problems, and anticipates future research directions in the technology of fault detection and intelligent diagnosis for wastewater treatment processes.
In order to solve the problems of poor blood compatibility and low adsorption capacity of chitosan (CS) when using graphene oxide (GO) alone, a graphene oxide/chitosan blend membrane (GO/CS membrane) was prepared. Microscopic morphology and composition analysis were conducted using SEM and FTIR, and bilirubin adsorption experiments were carried out on GO/CS membranes. The results showed that when the mass fraction of GO in the casting solution was 3%, the adsorption capacity of GO/CS membrane for bilirubin was optimal. The absorption intensity of C=O belonging to the amide group increases near 1 650 cm-1, while the stretching vibration peak of -NH2 at 3 353 cm-1 and the bending vibration peak of N-H at 1 570 cm-1 weaken simultaneously. Additionally, there is no stretching vibration peak of carboxyl group C=O near 718 cm-1, indicating that an amide reaction has occurred between GO and CS molecules, and the GO/CS membrane has been successfully prepared. Under the conditions of a reaction temperature of 37 ℃ and an adsorption time of 120 min, the GO/CS membrane exhibits the best bilirubin adsorption effect, with a saturated adsorption capacity of 77.8 mg/g. Increasing the mass concentration of bilirubin and lowering the pH under alkaline conditions are both beneficial for adsorption. Increasing the ionic strength of the solution or the mass concentration of bovine serum albumin is not conducive to the adsorption of bilirubin.
In the process of oil exploitation, processing, storage and transportation, the total petroleum hydrocarbon (TPH) released into the soil not only changes the physical and chemical properties of the soil, but also seriously affects the quality of the water environment through the process of migration and transformation. Addressing the environmental issue of petroleum?contaminated soils, the development of efficient, green, and environmentally friendly remediation technologies has become a critical need in the industry. This paper reviews the main remediation technologies for petroleum?contaminated soils based on current domestic and international research. The study showed that physical methods are suitable for remediating soils contaminated with highly volatile and highly permeable petroleum, chemical methods are appropriate for treating severely and recalcitrantly contaminated soils, and biological methods are more environmentally friendly and better suited for treating mildly contaminated soils. By comparing the principles and application ranges of different remediation technologies, it is evident that combined remediation technologies offer strong versatility and widespread applicability. This paper also explores future trends in the development of green and environmentally friendly remediation technologies for petroleum?contaminated soils, aiming to provide a reference for practical applications in soil remediation.
A novel adsorption material of bimetallic Cu and Ni?doped TiO2?modified carbon nanotubes was prepared by sol?gel methodmethod,and experiments on simultaneous desulfurization and denitrification were carried out.The effects of O2 volume fraction,H2O volume fraction and volume airspeed on desulfurization and denitrification were studied,Under the condition of a molar ratio of Cu to Ni of 2.The results showed that the adsorption capacity of MWCNTs/Cu?Ni?TiO2 was significantly better than that of single?metal modified materials. Under the condition of simulating flue gas, the adsorption effect of the bimetallic modified material was the best when the mass concentration of SO2 was 3 140 mg/m3, the mass concentration of NO was 736 mg/m3, the volume fraction of water vapor was 5%, the fraction of O2 was 8%, and the volume space velocity was 2 598 h-1. The optimal adsorption amount of SO2 was 20.43 mg/g, and the optimal adsorption amount of NO was 0.86 mg/g.
The anode materials play a crucial role in the components of sodium?ion batteries. Petroleum coke serves as an important precursor for the preparation of carbon anode for sodium?ion batteries. In this study, the effects of carbonization temperature and sulfur content on the structure of petroleum coke anode were characterized by XRD and Raman spectroscopy, and the changes of sodium storage properties for different structured anodes were analyzed. The results show that the anode has a balanced defect density and interlayer spacing and excellent conductivity, which exhibits better electrochemical performance at 1 000 ℃. The discharge capacity at a current density of 50 mA/g is 434 mA?h/g. The presence of sulfur inhibits the rearrangement and growth of carbon layer. With the increase of sulfur content of petroleum coke, the anode material exhibits higher sodium storage capacity and better cycle life and rate performance, while the initial coulomb efficiency decreases from 65% to 54%, posing significant challenges for future research.
The spinel?phase Zn2Ga2.98-x Ge0.75O8:Cr0.02, La x (x=0.005,0.010,0.015,0.020,0.025) nanoparticles were synthesized by a hydrothermal method in combination with a subsequent heat treatment. With the La3+ doping concentration increasing from 0 to 0.025, the average particle size of these nanoparticls increased from 64 nm to 78 nm. Under 590 nm excitation, La3+?doped ZGGO nanoparticles exhibited stronger narrow?band NIR emission peaked at 697 nm, originating from the 2E(2G)→4A2(4F) transition of Cr3+. From the TEM and emission spectral analyses, it can be found that the increased NIR persistent luminescence is attributed to the increased particle size and the increased number of luminescent centers in a relatively strong crystal field environment. On the basis of thermoluminescence spectra and the afterglow decay curves, it can be found that La3+ doping leads to the formation of more traps related to the thermal activation process and the afterglow time exceeding 15 h.
Risk evaluation is the core work of pipeline integrity management and the prerequisite and foundation for realizing risk prevention management. Zhoushan submarine pipeline has harsh service conditions, difficult monitoring and maintenance, and serious consequences of accidents. In order to ensure the safe operation of the submarine pipeline. Integrating the service conditions and operational characteristics of the Zhoushan section of the Xinao LNG submarine pipeline, this study first identifies risk factors through systematic hazard analysis. Subsequently, the modified Kent methodology is applied to quantify relative risk values. According to the size of the relative risk value, the risky pipeline sections of this LNG pipeline system were graded. The results show that the relative risk value of the Zhoushan section of the submarine pipeline is predominantly within the 100~200 range, and the risk rating is at a low level. Meanwhile, risk management measures and recommendations for Zhoushan submarine pipeline are proposed. These strategies are aimed at promoting the realization of a risk?level?based management mechanism, thus providing scientific guidance and reference bases for the safe operation of submarine pipelines.
The optimization process in reservoir history matching belongs to the high?dimensional system's optimal control problem, and the selection of a suitable optimization algorithm is crucial for achieving a good fitting effect. As gradient?based methods face challenges in computing the gradient of the objective function, intelligent optimization algorithms with stochastic properties are widely applied in reservoir optimization processes. A method for reservoir history matching based on real?number coding genetic algorithm RGA and connectivity model was proposed. This method eliminates the need for encoding and decoding operations by directly using feasible solutions obtained from traditional solving methods as initial parameters for the improved genetic algorithm, thereby reducing the complexity of the search space. In RGA, real?number coding is employed to represent parameters, enabling the algorithm to handle continuous variables directly, thus enhancing search accuracy and convergence speed. A adaptive selection strategies, crossover, and mutation operations are introduced in this paper to further enhance the algorithm's performance. Application of RGA to the history matching problem in a mechanistic model demonstrates that RGA can effectively improve fitting results and find relatively optimal solutions in a short time. Therefore, this method has significant potential for widespread application in reservoir history matching problems.
Using molecular dynamics, the lowest energy configurations of n?dodecane, n?octadecane, and n?nonadecane were constructed, and the interactions between oil molecules and wax molecules were studied at different water contents (mass fractions). The molecular dynamics model of crude oil emulsion system based on different mass fraction water content was constructed. The effect of water molecules dissolved in the system on the viscosity of waxy crude oil was studied. The radial distribution functions of wax molecules in different water content systems were compared. The results show that carbon number is the main factor to determine the interaction energy between crude oil molecules. With the increase of water content, the distance between molecules increases, while the interaction energy decreases. After water molecules are dissolved in the system, the distance between wax molecules and electrostatic interaction become larger, the distribution of wax molecules becomes disordered, and the flow characteristics of crude oil are improved.
Centrifugal compressors are key equipment in the natural gas pipeline network of the petrochemical industry, and their high failure rate can cause significant economic losses to the affiliated enterprises. This article proposes an ontology based fault diagnosis method for centrifugal compressors. Firstly, this method takes the centrifugal compressor fault analysis reports accumulated by petrochemical enterprises as the knowledge source, extracts fault diagnosis knowledge from the knowledge source through ontology modeling, and promotes the integration, sharing, and reuse of fault diagnosis knowledge. Then, a fault diagnosis knowledge base was constructed using the ontology software Protégé, and rule?based reasoning (RBR) was implemented using the Semantic Web Rule Language (SWRL). The knowledge was stored and queried using the software Neo4j. The effectiveness of this fault diagnosis method has been confirmed through testing the oil system composed of centrifugal compressors. The results show that this method improves the application efficiency of fault knowledge and provides a high?quality knowledge foundation for the diagnosis and decision?making of centrifugal compressors.
In order to enrich the understanding of the mixing characteristics of various stirring paddles, the effects of rotational speed and immersion depth of six types of stirring paddles such as Paddle Straight Blade Paddle, Paddle Inclined Blade Paddle, Six Straight Blade Turbine Paddle, Six Inclined Blade Turbine Paddle, Straight Blade Rushton Paddle (Disc Straight Blade Turbine Paddle), Inclined Blade Rushton Paddle (Disc Inclined Blade Turbine Paddle ), on the mixing time, power, power quasi?counts, the number of mixing times, the number of mixing efficiencies, have been analyzed in depth. The results showed that the mixing time, power, power quasi number, mixing time number and mixing efficiency number were affected by the rotational speed and submergence depth of six types of stirring paddles. When the rotational speed of the paddle is 150 r/min, the mixing time decreases and then increases with the increase of the submergence depth, in which the power required by the inclined?blade Rushton paddle is the smallest, the mixing rate is the largest, and the mixing efficiency is the highest; when the submergence depth is 25 cm, the mixing time of the six types of paddles decreases with the increase of rotational speed, and the power required by the inclined?blade Rushton paddle is the smallest, the mixing rate is the largest, and the mixing efficiency is the highest; and the mixing time of the six types of paddles is the largest. When the rotational speed and submergence depth are certain, the power required by the Rushton paddle is the smallest and the mixing efficiency is the highest; the integrated mixing performance of the Rushton paddle is the best. The results of the study provide both experimental data for the industrial applications and a theoretical basis for the optimization of the subsequent design of stirring paddles.
An improved ant colony algorithm is proposed to address issues such as susceptibility to local optima and slow convergence speed. Firstly, the relationship between the current target node and the next target node and the normal distribution function are introduced into the heuristic function, enhancing the algorithm's search capability in the early stages. In addition, by introducing an inflection point factor, the diversity of directional selection is enhanced. Secondly, an adaptive dynamic pheromone volatility coefficient is proposed to adjust the pheromone evaporation rate adaptively, modifying the pheromone update rules. Finally, simulation experiments were conducted using Matlab to compare the traditional ant colony algorithm and the improved ant colony algorithm on three different grid maps. The experimental results demonstrate that, compared with the traditional ant colony algorithm, the improved algorithm exhibits advantages such as faster convergence speed, shorter paths, and fewer inflection points.
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