Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
Not a member yet
23976 research outputs found
Sort by
Highly dispersed and stable Schiff base nickel catalyst on multi-walled carbon nanotubes promote ethylene oligomerization
No full textalpha-Olefins are essential chemical raw materials in the synthesis of emulsifiers, plasticizers, and other value-added chemicals, and ethylene oligomerization is the main method used for preparing alpha-olefins. However, catalysts employed in ethylene oligomerization have drawbacks such as poor selection of target products, catalyst particle aggregation, and deactivation. To prevent the aggregation of the catalyst and expose a large number of active sites, we propose an anchoring strategy to stabilize and uniformly disperse catalysts on multi-walled carbon nanotubes (MWCNTs). Hybrid catalysts (SCn@MWCNTs) fabricated using the strategy exhibited considerably higher catalytic performance compared with homogeneous Schiff base nickel catalysts (SCn) owing to the combined effects of MWCNTs and active nickel centers. Under optimal catalytic conditions (temperature: 25 degrees C; Al/Ni molar ratio: 500 (SCn); Al/Ni molar ratio: 700 (SCn@MWCNTs); pressure: 0.7 MPa), the activities of SC1 and SC1@MWCNTs were 6.56 x 104 and 8.25 x 104 g/(mol Ni & sdot;h), respectively. In particular, SC1@MWCNTs showed remarkable recyclability and catalytic stability
Study on the Micromorphology and Rheology of Tetrahydrofuran Hydrate during Formation and Dissociation Processes
No full textClarifying the flow properties of hydrate slurries is of paramount importance for flow assurance in oil and gas pipelines and the application of hydrate technologies. In this study, the formation and dissociation processes of tetrahydrofuran (THF) hydrate at different concentrations and temperatures were observed by a visualized rheometer for the first time, and the influence of the micromorphology of THF hydrate on its rheology was discussed. Otherwise, observations indicate that under shear conditions, the morphology of THF hydrates transforms from nearly 2D plate-like crystals to 3D aggregates, accompanied by a sharp increase in the viscosity of the THF hydrate slurry. The results show that both temperature and concentration impact the crystal morphology of THF hydrates, thereby affecting the rheological properties of the hydrate slurry. Higher temperatures result in smaller aggregate volumes and lower peak viscosities, making the hydrate aggregates more prone to fragmentation under flow conditions. Conversely, higher concentrations lead to greater peak viscosities, with aggregate volumes initially increasing and then decreasing, making the aggregates more resistant to breakage at a concentration of 30 wt %. Compared to temperature, THF concentration exerts a more significant influence on the morphology and rheological properties of hydrates. Additionally, by observing the dissociation process of THF hydrates under static conditions, two primary states of hydrate dissociation were identified, both of which generate a large number of bubbles toward the end of the dissociation process
Multi-objective optimization of the configuration of Electric vehicle charging piles based on scenario analysis
No full textAbstract
The optimization of electric vehicles (EVs) charging piles configurations is explored across varying demand levels, land prices, and unit time cost, with the aim of minimizing users’ waiting times and construction operation and maintenance costs. The analysis indicates that a significant reduction in user waiting times can be achieved through the increase of charging piles, with only a marginal rise in construction operation and maintenance cost, proving to be economically beneficial, especially in scenarios of high user time cost. After determining the minimum number of charging piles according to the charging demand, adding 1 to 4 charging piles based on it is the most direct and convenient method to determine the configuration of charging piles
Effect of hydrochar from biogas slurry co-hydrothermal carbonization with biomass on anaerobic digestion performance of food waste
No full textAnaerobic digestion is a promising method for converting food waste into renewable methane-rich biogas. However, challenges, such as significant biogas slurry generation, poor stability, and low methane production, limit its widespread adoption. This study produced 15 types of hydrochars by co-hydrothermal carbonization of biogas slurry with sugarcane leaves, cellulosic ethanol residue, or food waste digestate at 180-260 degrees C to enhance anaerobic digestion performance and methane yield. The methane yield was influenced by both the raw materials and hydrothermal carbonization temperature. The hydrochar derived from sugarcane leaves at 180 degrees C exhibited the highest methane yield of 461.59 mL/g VS, which is a 13.69% increase over the food waste group. Additionally, different doses of SL-180 were tested for their effects on the anaerobic digestion performance in food waste. The cumulative methane yield increased from 379.68 mL/g VS to 543.26 mL/g VS with SL-180 dosages ranging from 5 g/L to 40 g/L, enhancing cumulative methane yield by 3.90-48.66 % compared to the food waste group. The primary factor influencing methane yield was hydrochar degradation, whereas secondary factors included maintaining system stability and enriching methane-producing microorganisms, particularly Methanosaeta and Methanomassiliicoccus. Energy assessment and economic analysis indicate that combining hydrothermal carbonization with anaerobic digestion can achieve high energy output and economic benefits. This study offers insights and recommendations for managing biogas slurry, resource recovery, and improving the stability and methane yield in the anaerobic digestion of food waste
Effect of hydrochar from biogas slurry co-hydrothermal carbonization with biomass on anaerobic digestion performance of food waste
No full textAnaerobic digestion is a promising method for converting food waste into renewable methane-rich biogas. However, challenges, such as significant biogas slurry generation, poor stability, and low methane production, limit its widespread adoption. This study produced 15 types of hydrochars by co-hydrothermal carbonization of biogas slurry with sugarcane leaves, cellulosic ethanol residue, or food waste digestate at 180-260 degrees C to enhance anaerobic digestion performance and methane yield. The methane yield was influenced by both the raw materials and hydrothermal carbonization temperature. The hydrochar derived from sugarcane leaves at 180 degrees C exhibited the highest methane yield of 461.59 mL/g VS, which is a 13.69% increase over the food waste group. Additionally, different doses of SL-180 were tested for their effects on the anaerobic digestion performance in food waste. The cumulative methane yield increased from 379.68 mL/g VS to 543.26 mL/g VS with SL-180 dosages ranging from 5 g/L to 40 g/L, enhancing cumulative methane yield by 3.90-48.66 % compared to the food waste group. The primary factor influencing methane yield was hydrochar degradation, whereas secondary factors included maintaining system stability and enriching methane-producing microorganisms, particularly Methanosaeta and Methanomassiliicoccus. Energy assessment and economic analysis indicate that combining hydrothermal carbonization with anaerobic digestion can achieve high energy output and economic benefits. This study offers insights and recommendations for managing biogas slurry, resource recovery, and improving the stability and methane yield in the anaerobic digestion of food waste
A newly early warning model for anaerobic digestion systems: Based on an improved sparrow search algorithm combined with least square support vector machine
No full textAnaerobic digestion as an important means of organic waste treatment will play a key role in the realization of ecological civilization and the goal of double carbon. However, the instability of the system due to the high sensitivity to operating conditions restricts the economy and sustainability of the current commercial biogas projects in China. Machine learning as an early warning and control tool for many industrial systems is also applicable to anaerobic digestion systems. Existing studies focus on the biogas or methane yield prediction of the system, while there are few studies have considered the acid-bases indicators, which is crucial to the stability of the system. In this study, an improved sparrow search algorithm was developed, and after comparing its performance with selected optimization algorithms using CEC2017 test suite, combined with LSSVM, was applied to the prediction of eight different indicators of anaerobic systems, and eight datasets were validated. The results show that the optimization algorithm proposed in this study improves the performance of LSSVM and the model of ISSALSSVM shows excellent potential in the early warning and controlling of anaerobic digestion system
Revealing the kinetic behaviors of hydrate formation on bubble surface with different pressure gradients in deep-sea methane seepage areas of the South China Sea
No full textIn the deep-sea methane seepage environment, hydrate formation on the methane bubbles is a crucial pathway for methane transformation, and plays an important role in determining whether seepage methane can enter the surface ocean. While how the pressure determines the hydrate formation process in different water depths remains unclear. In this study, we investigated the formation kinetic characteristics and microstructure evolution of methane hydrate on suspended gas bubbles within varied pressure conditions. The pressure range (4-14 MPa) was in the deep-sea methane seepage environment. The results indicated that pressure obviously affected the hydrate film formation characteristics. As pressure increased, the lateral growth rate of the hydrate film accelerated, the hydrate crystal particles became smaller, and the initial hydrate film surface became smoother. Raman spectroscopy results showed that pressure changes did not obviously alter the microporous evolution on the hydrate film surface, that the gas-phase/water-phase Raman peak area ratio exhibited similar trends. The dissolved methane concentration under different pressure conditions was not the primary factor affecting hydrate thickening, rather, it depended mainly on the driving force. This study is of great significance in revealing the characteristics of methane hydrate formation and methane transfer in the oceanic methane seepage environment
Revealing the kinetic behaviors of hydrate formation on bubble surface with different pressure gradients in deep-sea methane seepage areas of the South China Sea
No full textIn the deep-sea methane seepage environment, hydrate formation on the methane bubbles is a crucial pathway for methane transformation, and plays an important role in determining whether seepage methane can enter the surface ocean. While how the pressure determines the hydrate formation process in different water depths remains unclear. In this study, we investigated the formation kinetic characteristics and microstructure evolution of methane hydrate on suspended gas bubbles within varied pressure conditions. The pressure range (4-14 MPa) was in the deep-sea methane seepage environment. The results indicated that pressure obviously affected the hydrate film formation characteristics. As pressure increased, the lateral growth rate of the hydrate film accelerated, the hydrate crystal particles became smaller, and the initial hydrate film surface became smoother. Raman spectroscopy results showed that pressure changes did not obviously alter the microporous evolution on the hydrate film surface, that the gas-phase/water-phase Raman peak area ratio exhibited similar trends. The dissolved methane concentration under different pressure conditions was not the primary factor affecting hydrate thickening, rather, it depended mainly on the driving force. This study is of great significance in revealing the characteristics of methane hydrate formation and methane transfer in the oceanic methane seepage environment
Access Repository Dashboard
Do you manage Institutional Repository of GuangZhou Institute of Energy Conversion, CAS? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!