Suchergebnisse

At present, large water demand and carbon dioxide (CO2) emissions have emerged as challenges of steam injection for oil thermal recovery. This paper proposed a strategy of superheated steam injection by the high-temperature gas-cooled reactor (HTR) for thermal recovery of heavy oil, which has less demand of water and emission of CO2. The paper outlines the problems of conventional steam injection and addresses the advantages of superheated steam injection by HTR from the aspects of technology, economy, and environment. A Geographic Information System (GIS) embedded with a thermal hydraulic analysis function is designed and developed to analyze the strategy, which can make the analysis work more practical and credible. Thermal hydraulic analysis using this GIS is carried out by applying this strategy to a reference heavy oil field. Two kinds of injection are considered and compared: wet steam injection by conventional boilers and superheated steam injection by HTR. The heat loss, pressure drop, and possible phase transformation are calculated and analyzed when the steam flows through the pipeline and well tube and is finally injected into the oil reservoir. The result shows that the superheated steam injection from HTR is applicable and promising for thermal recovery of heavy oil reservoirs.

Helically coiled tube Once-Through Steam Generator (H-OTSG) is one of the key equipment types for small modular reactors. The flow instability of the secondary side of the H-OTSG is particularly serious, because the working condition is in the range of low and medium pressure. This paper presents research on density wave oscillations (DWO) in a typical countercurrent H-OTSG. Based on the steady-state calculation, the mathematical model of single-channel system was established, and the transfer function was derived. Using Nyquist stability criterion of the single variable, the stability cases were studied with an in-house computer program. According to the analyses, the impact law of the geometrical parameters to the system stability was obtained. RELAP5/MOD3.2 code was also used to simulate DWO in H-OTSG. The theoretical analyses of the in-house program were compared to the simulation results of RELAP5. A correction factor was introduced to reduce the error of RELAP5 when modeling helical geometry. The comparison results agreed well which showed that the correction is effective.

This book captures an epochal juncture of two of the world's most transformative processes: the People's Republic of China's rapidly expanding sphere of influence across the global south and the disintegration of the Amazonian, Cerrado, and Andean biomes. The intersection of these two processes took another step in April 2020, when Chinese President Xi Jinping launched a "New Health Silk Road" agenda of aid and investment that would wind through South America, extending the Eurasian-African "Belt and Road Initiative" to the Latin American tropics. Through thirty short essays, this volume brings together an impressive array of contributors, from economists, anthropologists, and political scientists to Black, feminist, and Indigenous community organizers, Chinese stakeholders, environmental activists, and local journalists to offer a pathbreaking analysis of China's presence in South America. As cracks in the progressive legacy of the Pink Tide and the failures of ecocidal right-wing populisms shape new political economies and geopolitical possibilities, this book provides a grassroots-based account of a post-US centered world order, and an accompanying map of the stakes for South America that highlights emerging voices and forms of resistance