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ObjectivesIn order to master the deep peak shaving capability of supercritical circulating fluidized bed units and scientifically participate in the auxiliary service market, it is necessary to conduct in-depth research on the deep peak shaving performance of existing units.MethodsFrom the three dimensions of safety, economy and environmental protection, 40% and 30% of rated load continuous trial operation, boiler combustion optimization adjustment, boiler efficiency and steam turbine heat consumption rate performance tests were carried out, respectively.More than 10 optimization measures such as single pump operation of feed water pump, pressure curve optimization, boiler oxygen amount, bed pressure adjustment, etc., were implemented.ResultsThe continuous operation of 30% rated load for 12 consecutive days was realized, 40% and 30% rated load depth peak-monasizing the peaks affected coal consumption by about 52%, 72 g/(kW·h), respectively.ConclusionsThe 350 MW supercritical circulating fluidized bed unit has good deep peak shaving ability. There is no need to transform 30% rated load conditions, and inject oil to stabilize combustion and maintain high efficiency of the boiler. Monitoring parameters for the steam turbine generator unit body, thermal system and auxiliary equipment are normal. The main flue gas pollutants are ultra-low emission.

Red hot exciton emitters with high exciton utilization efficiencies (EUEs) are scarce. Herein, three red emitters, 2TPA, TPAPXZ, and TPAPXZCN, are designed and synthesized. These emitters have large rigid structures and large spin‐orbit coupling between the high‐lying triplet and adjacent singlet states. Photophysical studies show that these emitters exhibit anti‐Kasha high‐lying triplet emissions. Moreover, the MADN host is doped with 5 wt.% of these emitters, which inhibits the internal conversion (IC) rate (kICTn ∼ 108 s−1) of the high‐lying triplet state, making it similar to the high‐lying reverse intersystem crossing (hRISC) rate (khRISC ∼ 108 s−1). It provides a basis for doped devices to achieve high EUEs. Using 2TPA, TPAPXZ, and TPAPXZCN as emissive layers, the doped devices achieve red emission with emission peaks at 628, 626, and 647 nm, respectively. Notably, these devices achieve high EUEs of 43.9%, 81.0%, and 62.6%, respectively. To this knowledge, the EUE of these devices is among the highest values reported for hot exciton material devices. This study provides a novel approach for addressing low EUEs of hot exciton materials and improving their design strategies. [ABSTRACT FROM AUTHOR]

How to evaluate and predict potential source terms quickly and effectively is very important for emergency response. In this paper, the traditional forward analysis calculation based on deterministic method was combined with probability theory calculation, and a large number of typical accident sequences were calculated with severe accident analysis software to obtain data of source terms. According to expert knowledge base, probabilistic safety analysis, and other information, a model of nuclear power plant was established based on Bayesian network algorithm, so as to carry out researches on rapid source term calculation and prediction methods. Based on the Bayesian network model of a specific power plant and the pre-calculated source term results of typical accident scenarios, the best available knowledge and observation results of events were used to estimate the relevant typical source terms and their possibilities, which provide a strong basis for effectively grasping and predicting the accident process, quickly predicting source terms and release characteristics of radioactive materials, and quickly and accurately evaluating the radioactive consequences. [ABSTRACT FROM AUTHOR]

Changes of porosity, permeability, and tortuosity due to physical and geochemical processes are of vital importance for a variety of hydrogeological systems, including passive treatment facilities for contaminated groundwater, engineered barrier systems (EBS), and host rocks for high-level nuclear waste (HLW) repositories. Due to the nonlinear nature and chemical complexity of the problem, in most cases, it is impossible to verify reactive transport codes analytically, and code intercomparisons are the most suitable method to assess code capabilities and model performance. This paper summarizes model intercomparisons for six hypothetical scenarios with generally increasing geochemical or physical complexity using the reactive transport codes CrunchFlow, HP1, MIN3P, PFlotran, and TOUGHREACT. Benchmark problems include the enhancement of porosity and permeability through mineral dissolution, as well as near complete clogging due to localized mineral precipitation, leading to reduction of permeability and tortuosity. Processes considered in the benchmark simulations are advective-dispersive transport in saturated media, kinetically controlled mineral dissolution-precipitation, and aqueous complexation. Porosity changes are induced by mineral dissolution-precipitation reactions, and the Carman-Kozeny relationship is used to describe changes in permeability as a function of porosity. Archie’s law is used to update the tortuosity and the pore diffusion coefficient as a function of porosity. Results demonstrate that, generally, good agreement is reached amongst the computer models despite significant differences in model formulations. Some differences are observed, in particular for the more complex scenarios involving clogging; however, these differences do not affect the interpretation of system behavior and evolution.

With the increasing scarcity of easy separation ores, utilization of refractory ores need to be solved urgently. A difficult-to-beneficiate ore in Heilongjiang has the features of high oxidation rate, low-grade of molybdenum, uneven grain size distribution, and difficult in separation of copper and molybdenum. The ore has not been exploited for many years, caused a great waste of resources. The low-grade molybdenum ore contains 0.033% molybdenum and 0.014% copper. The molybdenum minerals in the ore mainly exist in the form of molybdenite, grain size is 0.01 - 0.50 mm, the average oxidation rate is 18.89 %. Copper minerals mainly exist in the form of chalcopyrite, grain size is 0.005 - 0.15 mm, the floatability of chalcopyrite is excellent, and the molybdenum concentration is difficult. According to the characteristics of the uneven size distribution of molybdenum minerals and fine particle size of copper minerals, a process flowsheet of "coarse grinding and roughing + fine grinding and cleaning" was designed, regarding chalcopyrite has the characteristics of good floatability and is difficult to inhibit. Inhibition effect of various copper depressants on copper-bearing minerals was investigated. The research find that new agent HL120 has the main component of hydroxylated xanthate with hydrophilic and hydrophilic groups, it is easier to adsorb on the surface of chalcopyrite, which can inhibit chalcopyrite more effectively. Using HL120 to inhibit chalcopyrite in molybdenum flotation, a molybdenum concentrate containing 48.87% Mo and 0.26% Cu with a molybdenum recovery of 82.43% was finally obtained. Study on flotation of the molybdenum tailings obtained a copper concentrate containing 16.88% Cu with copper recovery 81.27% for the operation and 47.66% for the raw ore. The low-grade ore was effectively utilized, and the economic benefits of the enterprise were significantly improved. [ABSTRACT FROM AUTHOR]

In this study, a concise and fast framework based on the average kernel and iterative direct numerical simulation is proposed to solve the generalized Smoluchowski coagulation equation with a physically realistic kernel. Taking advantage of the symmetry of the homogeneous collision kernel, the realistic kernel function can be represented as a simple power function through Laplace transformation under the average kernel method, and the corresponding moment model and self-preserving model can then be constructed and solved analytically. Compared with the classical Taylor-series expansion method of moments, the present moment model has the same asymptotic growth rate, but the form is more concise and the particle number density is decoupled from the other moments. To obtain a better agreement with the experimental data, the iterative direct numerical simulation can be employed to correct the similarity solution using the analytical similarity solution as the initial condition. The corrected similarity solution overcomes the inherent contradiction between the analytical solution and experimental data discussed in the literature. The results reveal that the shape of self-preserving distribution is independent of the initial distribution and that it does depend on the mechanism of coagulation. The results also show the universality, reliability, and strong robustness of the iterative direct numerical simulation algorithm. [ABSTRACT FROM AUTHOR]