Process Safety and Environmental Protection最新文献

This study aims to propose and evaluate two acrylic acid (AA) production processes that utilize bio-based crude glycerol as a feedstock. Scheme 1 employs acrolein as an intermediate, while Scheme 2 utilizes allyl alcohol as an intermediate. For process intensification, Scheme 1 employs a one-pot reactor configuration that couples the glycerol dehydration and oxidation reactions and uses an additional reactor to suppress the formation of side products. Scheme 2 implements a membrane that helps prevent the multiple azeotropic distillation between water and other substances. Furthermore, both processes were systematically optimized based on varying levels of information available in the process (i.e., three objectives for Scheme 1, single objective for Scheme 2). From a techno-economic evaluation, Scheme 2 (2.136 USD/kg) slightly outperforms Scheme 1 (2.514 USD/kg) in terms of the minimum required selling price (MRSP). Both values are significantly higher than the market price (1.24–1.32 USD/kg) based on the conventional process that uses propene as a feedstock. Subsequently, a cradle-to-gate life cycle assessment was conducted to compare these processes across five impact categories (i.e., global warming potential, fossil source scarcity, human non-carcinogenic toxicity, water consumption, and terrestrial acidification). We have observed that Scheme 1 can be more sustainable than Scheme 2 and the conventional process if the issue associated with the acrolein left in the wastewater can be addressed. In contrast, Scheme 2 is far from environmentally friendly even compared to the conventional process, primarily because of the use of formic acid as a co-reactant.

A novel S-scheme 2D/2D boron-doped nitrogen-deficient g-C₃N₄/ZnIn₂S₄ (BDCNN/ZnIn₂S₄) heterojunction was successfully fabricated via the in-situ assembly of ZnIn₂S₄ onto BDCNN in an oil bath. To assess the quality and characteristics of the synthesized photocatalysts, a comprehensive range of characterizations were conducted. The innovative S-scheme 2D/2D BDCNN/ZnIn₂S₄ heterojunction, equipped with a deliberately established inter-built electric field, facilitates rapid electron transfer and enhanced separation efficiency of photo-induced carriers. Consequently, this heterojunction demonstrates remarkable enhancements in both H₂ production and TC degradation under visible-light illumination (λ > 420 nm). The optimized BDCNN/ZnIn₂S₄ heterojunction exhibited impressive photocatalytic performance, achieving a promising H₂ evolution rate of 2378.8 μmolg⁻¹h⁻¹ and a high degradation efficiency exceeding 90 % (k = 0.021 min⁻¹) for TC. This noteworthy improvement in photocatalytic performance is primarily attributed to the synergistic effects of boron-doping and nitrogen-defects within BDCNN, coupled with the unique S-scheme photocatalytic mechanism inherent to the BDCNN/ZnIn₂S₄ heterojunction. Overall, this study introduces a groundbreaking approach for constructing 2D/2D g-C₃N₄-based heterojunctions that exhibit exceptional visible-light photocatalytic capabilities, thereby offering significant potential for various photocatalytic applications.

The ineffective utilization of resources and the potential harm to the ecological environment are both consequences of the accumulation of red mud (RM). This study focuses on synthesizing ferromagnetic materials (FMs) through a hydrometallurgical method, using compounds containing iron (CCI) derived from RM. The study primarily focused on process design, thermodynamic analysis, and environment assessment. Effectively, this procedure resulted in the production of two varieties of FMs: Fe₂O₃ and Fe₃O₄, exhibiting purities of 94.8 % and 98.6 %, correspondingly. The utilization of different concentrations of various flocculants (APAM, PAM, and CPAM) resulted in a substantial improvement in the flocculation process, with APAM demonstrating superior effectiveness. Based on the results of environmental assessments, it was found that the levels of toxic and hazardous substances in the residual solids were below 0.01 wt%, while in wastewater they were below 10⁻⁶ mol L⁻¹. Furthermore, the study put forward mechanisms to explain phase transformation, flocculation, and magnetic separation. The thermodynamic calculation provided insights into the energy variation and reaction extent during the controllable synthesis of FMs. The current study provides a feasible resolution to improve the efficiency of resource recovery and reduce environmental pollution, thus encouraging the adoption of cleaner production methods.

With the intervention of the industry in every aspect of human lifestyle on the one hand, and the prompt reduction in fossil fuel and their harms to the environment, including global warming, on the flip side, the importance of renewable sources of energy has been revealed more than ever. The presented study attempted to investigate a new configuration for a trigeneration configuration based on a solar renewable source. The proposed system comprises a parabolic trough solar collector segment to drive a transcritical carbon dioxide power and refrigeration subsystem, a dual-pressure organic Rankine cycle, and a thermal vapor compression process combined with a multi-effect desalination unit. The suggested configuration is carefully inspected from thermodynamic and economic perspectives, encompassing an analysis of a certain condition and a detailed parametric evaluation. Four decision parameters are employed for the parametric evaluation, in conjunction with two scenarios from a multi-objective particle swarm optimization combined with a linear programming method for multidimensional preference analysis as a decision-maker. The examination outputs bring out a net output power of 12.147 MW, a 7.707 MW cooling load, a 4.448 kg/s freshwater, and energetic and exergetic efficiencies of 15.286 % and 10.192 %, respectively. Moreover, examining the system's performance from an economic perspective reveals a total product cost rate of 954.249 $/h, leading to a 4.694-year payback period. This study optimizes energy usage and minimizes waste, offering industrial applications such as reducing fossil fuel dependence and lowering greenhouse gas emissions. It supports sustainable development and facilitates the global transition to cleaner energy sources.

Hydrogen-containing and hydrocarbon fuels have been widely used in industrial production. Jet fires involving these fuels emerge frequently after leakage or explosion accidents for gas pipelines and processing equipments. To reveal the influencing mechanisms of inclination angle on the pulsation behaviors of jet fires, the burning experiments of hydrogen, syngas, methane and propane jet fires with a nozzle diameter ($D$) of 15 mm, inclination angles (${\theta }_0)$ of 0°∼90°, fuel flow rates ($Q_f)$of 2.5–40 L/min were conducted. The variations of the global and spatial pulsation frequencies with inclination angle and fuel flow rate are sensitive to the fuel types. Subharmonic pulsation was found at large fuel flow rates ($Q_f>Q_{\mathrm{cri}}$). For hydrogen-containing jet flame, a transition from natural pulsation to subharmonic pulsation occurs at a critical inclination angle (${\theta }_{\mathrm{cri}}$). In this case, the transition height where the local pulsation frequency begins to be dominated by subharmonic pulsation, increases with the inclination angle. The local Richardson number ($R{i}_y$) at the transition height is close to 1. The interaction between the inner and outer vortices increases with the decrease of inclination angle, resulting in decreased natural frequency at the nozzle exit. With the theoretical velocity and flame width at y/D = 2, a unified dimensionless model of natural pulsation frequency was developed, $S{t}_y=0.41{\left(1/F{r}_y\right)}^{0.5}$, reasonably predicting the natural pulsation frequency of jet flames under different conditions.

Microbial fuel cells (MFCs) represent a promising technology for simultaneous electricity generation and wastewater treatment. In this study, a single-chambered MFC was fabricated utilizing a novel polymer electrolyte membrane synthesized from sulfonated polyether ether ketone grafted with styrene sulfonic acid (SPEEK/SSA) as the base polymer, and silica decorated with phosphomolybdic acid (SPMA) as a functionalized nanofiller. Various concentrations of SPMA (2.5 %, 5 %, 7.5 %, and 10 %) were incorporated into the SPEEK/SSA membranes and characterized physicochemically. The SPEEK/SSA membrane with 5 wt% SPMA demonstrated the highest proton conductivity (3.75×10⁻² S cm⁻¹) and ion exchange capacity (1.68 meq g⁻¹). This PEM also exhibited superior tensile strength (20 MPa) and excellent chemical durability, as evidenced by Fenton's reagent test. Performance evaluation revealed that this membrane achieved a maximum power density of 196.6 mW m⁻² at a maximum of 180 mA m⁻² current density. Additionally, antibiofouling tests indicated that the 5 % SPMA-incorporated membrane possessed significant antibacterial properties against both gram-positive and gram-negative bacteria and exhibited high biofilm inhibition. The wastewater treatment efficacy of the MFC with the 5 % SPMA membrane was confirmed by a chemical oxygen demand (COD) removal efficiency of 81.49 %, indicating its potential for effective wastewater treatment. Phylogenetic analysis through 16S rRNA sequencing identified major bacterial phyla including Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes, with predominant genera such as Pseudomonas and Acidovorax. This study emphasises the potential of nanocomposite membranes to enhance the performance and durability of MFCs while mitigating biofouling, thereby paving the way for future research and development in this field.

The need for efficient and dependable lithium-ion battery packs has significantly increased as a result of the progressively rising sales of electric vehicles (EVs). Thermal management is one of the key factors in battery performance and durability. To avoid thermal deterioration, improve safety, and maximize system effectiveness, the battery pack's temperature must be carefully managed. These battery systems' potential for thermal runaway has raised concerns about how safely they can be operated in harsh environments. Environmental considerations, governmental laws, and developments in battery technology are driving the switch from internal combustion engines to electric automobiles. Lithium-ion batteries are sensitive to temperature variations and operating them outside the optimal temperature range can lead to accelerated degradation, reduced capacity, and compromised safety. Key performance indicators used to assess battery thermal management system effectiveness include temperature uniformity, cooling effectiveness, energy usage, and effect on battery life. This paper describes an experimental investigation that looked at how lithium-ion EV battery packs behaved in harsh environments. It also suggests a unique strategy to prevent thermal runaway by using materials like Transformer Oil (TO) and Phase Change Materials (PCM). A specially built experimental setup was created to undertake this inquiry in order to imitate several extreme situations, including high ambient temperatures. A lithium-ion (NMC) battery pack (7S3P) was put through the experimental phase's predicted harsh circumstances to see how it would react thermally. In order to obtain insight into the underlying mechanisms causing thermal runaway, the data acquired were evaluated, and crucial thermal metrics like temperature distribution, heat dissipation, and thermal gradients were studied. The experiment's findings showed that under extreme circumstances, conventional cooling techniques were ineffective in preventing thermal runaway, which resulted in serious safety risks and a reduction in battery performance. The suggested strategy, which incorporates PCM and TO, was then put into practice to fix these flaws and improve battery safety. Due to their ability to self-regulate, they served as components that prevented thermal runaway by limiting the rise in temperature under high-stress situations.

A three-dimensional electrochemical reactor (3DER) with Ce-modified CoFe-LDHs as particle electrodes is assembled and used to efficiently degrade N-Nitrosopyrrolidine (NPYRs) in disinfected water. The construction of hierarchical structure and oxygen vacancies accelerates the electron transfer rate, provides a suitable working potential range and reduces electrochemical resistance, which leads to improved removal efficiency. The optimised particle electrodes (Co₂Fe_0.84Ce_0.16-LDHs@AC) achieved NPYR degradation of 81.5 % after 120 min of continuous treatment with low energy consumption of 2.4 kWh mg^–1 NPYR (current density of 5 mA cm⁻², flow rate of 3 mL min⁻¹, electrolyte concentration of 0.21 mol L⁻¹, and a pollutant concentration of 10 mg L⁻¹). Based on GC-MS, LC-MS analysis and quenching experiments, the degradation pathway of NPYR is proposed, while reactive oxygen species (ROS) during the degradation process include •OH, O₂^•− and ¹O₂. The modification of Ce in LDHs has a significant role in enhancing degradation efficiency by accelerating the formation of ROS, which provides an efficient solution to the material design used in the 3DER system for boosting pollution degradation during water treatment.

To support the landfill design and waste management in rural areas of China, solid waste covering eight provisional regions was collected and tested in the laboratory to characterize its physical properties (composition, moisture content, specific gravity, dry unit weight) and mechanical properties (compressibility and shear strength). The results show that, compared with solid wastes from urban areas (MSW), solid waste from rural areas (RSW) comprised a much lower content of soil-like, gravel, and inert waste and a significantly higher content of combustible waste, thereby yielding a much lower specific gravity and dry unit weight. Similar to MSW, the compression index of RSW correlated well with its physical properties. However, its strength properties displayed divergence. Notably, the friction angle φ' of RSW remained relatively consistent, ranging from 28.4° to 30.9°. This narrow range is attributed to RSW's higher combustible-to-inert (CI) ratio compared to MSW. The cohesion intercept c' of RSW ranged from 13.5 to 24.9 kPa, showing a positive correlation with the fiber content without considering contribution from paper waste. This finding combined with data from the literature further revealed that the trend of increasing cohesion intercept with increasing fiber content became weakened over time. Relationships between φ' and c' versus C/I for RSW observed in this study will serve as an extension to the existing finding reported for MSW in the literature, i.e., for predominately combustible waste with C/I exceeding 10, constant values of strength parameters (i.e., moderate values φ' = 30°, c' = 20 kPa) are recommended. The results of this study are useful for the capacity design and slope stability analysis of landfills as well as waste recycle and reuse, ensuring a sustainable development of environment in China.