Carbon Nanostructures Production by AC Arc Discharge Plasma Process at Atmospheric Pressure

Carbon nanostructures have received much attention for a wide range of applications. In this paper, we produced carbon nanostructures by decomposition of benzene using AC arc discharge plasma process at atmospheric pressure. Discharge was carried out at a voltage of 380 V, with a current of 6 A–20 A. The products were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), and Raman spectra. The results show that the products on the inner wall of the reactor and the sand core are nanoparticles with 20–60 nm diameter, and the products on the electrode ends are nanoparticles, agglomerate carbon particles, and multiwalled carbon nanotubes (MWCNTs). The maximum yield content of carbon nanotubes occurs when the arc discharge current is 8 A. Finally, the reaction mechanism was discussed

Experimental investigation on plugging performance of nanospheres in low-permeability reservoir with bottom water

The oil production rate decreases rapidly after a short period of high yield from acidizing or fracturing in low-permeability reservoirs. In this paper, nanospheres are applied before the fracturing step, which possess the ability to absorb water and expand in the water layer, reducing the flow capacity of bottom water and finally enhancing the oil recovery. The plugging performance is investigated by nanosphere displacement  experiments in cores and sand-packs, which explores the plugging effect in the oil layer, the oil-water transition zones, the water layer and the fracturing zones. In addition, a nuclear magnetic resonance experiment is conducted to study the flow mechanism of nanospheres and determine the plugging rates, which can characterize the plugging performance of nanospheres in porous media. The results show that the plugging rate is 85.84% and 78.65% on the water layer and oil-water transition zone, respectively, and 94.36% in the fracturing zone. Meanwhile, the nanospheres cannot plug the oil layer. The formation pressure has a less considerable effect on the plugging performance of nanospheres. The nanospheres have good injectivity, and the intensity variations in small, medium and large pores account for 34.46%, 13.22% and 52.32%, respectively. Overall, this paper explores the feasibility of applying nanospheres for water plugging and enhanced oil recovery.Cited as: Tang, M., Wang, C., Deng, X., Yang, H., Lu, J., Yu, H. Experimental investigation on plugging performance of nanospheres in low-permeability reservoir with bottom water. Advances in Geo-Energy Research, 2022, 6(2): 95-103. https://doi.org/10.46690/ager.2022.02.0

Difference analysis method of grid connection influence between CRE and DRE based on bus state trajectory

This paper presents a method to investigate the impact of centralized and distributed renewable energy on the power grid system, aiming to discern their differences. First, we derived the coupling relationship between renewable energy permeability and access point voltage under a simplified model. Second, we proposed a holomorphic embedding model designed for non-global variation, enabling the construction of the bus state trajectory index. This index is employed to analyze the influence of centralized and distributed renewable energy access on power grid stability and voltage under low-permeability conditions. Furthermore, under high permeability, we determined the limit permeability of centralized and distributed renewable energy. Last, we provided renewable energy configuration recommendations to enhance the system’s receptive capacity