Author Affiliations
1College of Chemistry, Fuzhou University, Fuzhou 350108, China2State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China3College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, China4Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, Chinashow less
Fig. 1. Diagram of straight pipe model, the area enclosed by the thick solid line is the cross section of the model (the grey part denotes the water in the secondary circuit, the blue part denotes the tube support plate) (color online)
Fig. 2. Calculated distribution of the fluid velocities in the secondary circuit model(a) Average velocity over cross sections at various heights, (b) Velocity distributions on three selected cross sections at z = 1.5 m, 2.0 m, 2.5 m, respectively, (c) Velocity distribution on the longitudinal section nearby a support plate at z = 2.0 m, see the dashed line of (b) for the location of the section
Fig. 3. Variation curve of average temperatures of water on different sections along the flow direction in the secondary side model
Fig. 4. Variation curve of the average volume fraction of gas along the flow direction on cross sections at different heights of the secondary circuit model, where the black squares indicate the locations of tube support plates
Fig. 5. Variation curve of the pH values of the water near the heat transfer tube wall along the axis of the secondary circuit model, where the sampling point coordinates are (12.525 mm, 0, z), 0≤z≤3.8 m (see the cross section of (b)). The various molar ratios of the binary alkalizers are also shown in the inset of the figure. (color online)(a) = 8.784 mol·m-3, (b) + cETA = 4.56 mol·m-3, (c) + cETA = 1.8 mol·m-3
Fig. 6. Relation curves of pH value with ETA concentration (cETA) change and change rate corresponding to two different alkalizer concentrations (1.8 mol·m-3, 4.56 mol·m-3) at z=1.5 m, 2.0 m two points respectively (shown in Fig.5)
材料 Material | 导热系数 Thermal conductivity / W·(m·K)-1 | 恒压热容Heat capacity at constant pressure / J·(kg·K)-1 | 密度 Density / kg·cm-3 |
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Inconel690 | 17 | 524 | 8 091 | 304SS | 19 | 505 | 7 746 |
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Table 1. Physical parameters of relevant materials
| 解离常数Dissociation constant | 相对挥发度Relative volatility |
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温度Temperature / K | 298.15 | 425.15 | 573.15 | 298.15 | 425.15 | 573.15 | 氨NH3 | 4.75 | 5.10 | 6.67 | 30 | 9.55 | 3.31 | 乙醇胺ETA | 4.5 | 4.82 | 6.20 | 0.01 | 0.09 | 0.33 |
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Table 2. The dissociation constant and relative volatility of NH3 and ETA at different temperatures
NH3:ETA浓度的预设配比 The assumed concentration ratio (NH3 :ETA) | 8∶1 | 1∶0 | 4∶1 | 2∶1 | 1∶1 | 1∶2 | 1∶4 | 1∶8 |
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二回路中NH3浓度 The assumed concentrations of NH3, c1 / mol·m-3 | 4.05 | 4.56 | 3.65 | 3.04 | 2.28 | 1.52 | 0.91 | 0.51 | 二回路中ETA浓度 The assumed concentrations of ETA, c2 / mol·m-3 | 0.51 | 0 | 0.91 | 1.52 | 2.28 | 3.04 | 3.65 | 4.05 |
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Table 3. The calculated concentrations of NH3 and ETA in the secondary circuit model with c1+c2 = 4.56 mol·m-3 ①
NH3:ETA浓度的预设配比 The assumed concentration ratio (NH3 :ETA) | 1∶1 | 1∶0 | 8∶1 | 4∶1 | 2∶1 | 1∶2 | 1∶4 | 1∶8 |
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二回路中NH3浓度 The assumed concentrations of NH3, c1 / mol·m-3 | 0.9 | 1.8 | 1.6 | 1.44 | 1.2 | 0.6 | 0.36 | 0.2 | 二回路中ETA浓度 The assumed concentrations of ETA, c2 / mol·m-3 | 0.9 | 0 | 0.2 | 0.36 | 0.6 | 1.2 | 1.44 | 1.6 |
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Table 4. The calculated concentrations of NH3 and ETA in the secondary circuit model with c1+c2 = 1.8 mol·m-3
热力学参数Thermodynamic parameters | 液相Liquid | 汽相Gas |
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密度Density / kg·m-3 | 740.25 | — | 比热容Specific heat capacity / J·(g·K)-1 | 5.396 2 | 1.990 6 | 液相动力黏度Dynamic viscosity, liquid phase / Pa·s | 9.138×10-5 | — | 导热系数Thermal conductivity / W·(m·K)-1 | 0.569 1 | 0.048 7 |
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Table 5. Thermodynamic parameters of water in its gas and liquid states
边界 Boundary | 类型 Type | 数值 Value |
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入口(z=0 m) Inlet | 水流速度 / m·s-1 水流温度 / K | 1.0 543.15 | 出口(z=3.8 m) Outlet | 水流压强 / MPa | 6.81 | 传热管壁Heat transfer tube wall | 热通量 / W·m-2 | 170 000~10 000z (0<z≤3.0) | 170 000~30 000z (3<z≤3.8) |
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Table 6. The boundary values of main parameters