The ammonium salt corrosion is a typical failure mode for the hydrogenation reaction effluent air cooler(REAC) system. In order to investigate the corrosion characteristics in the REAC system, numerical simulations we...The ammonium salt corrosion is a typical failure mode for the hydrogenation reaction effluent air cooler(REAC) system. In order to investigate the corrosion characteristics in the REAC system, numerical simulations were performed by using the mixture model, the heating transfer model, and the particles tracking model. The results show that the differences between the temperature and the velocity at each cross section of the first-row and second-row tubes are small. The inertia of the particles plays an important role in the particle’s deposition, and the smaller particles distribute more uniformly in the air cooler. However, for larger particles, they prefer falling from the inner side of the vertical elbow, and preferentially depositing at the inlet header and pipes before saturation. In the heat exchanger tubes, the particle deposition number is larger in the second-row tubes than that in the first-row tubes, and the high-risk tubes mainly concentrate on the middle and right side of the air cooler. The kinetic parameters of the particles are in accordance with the blocking-prone position in many real operating conditions.展开更多
渣油加氢装置因原料劣化腐蚀性强,设备长期处于极端运行工况下,导致冷换设备铵盐腐蚀性风险大。以沸腾床渣油加氢系统空气冷却器(简称空冷器)为研究对象,采用NRTL-RK模型构建多组分体系下反应流出物系统化学离子-平衡模型,并通过工艺过...渣油加氢装置因原料劣化腐蚀性强,设备长期处于极端运行工况下,导致冷换设备铵盐腐蚀性风险大。以沸腾床渣油加氢系统空气冷却器(简称空冷器)为研究对象,采用NRTL-RK模型构建多组分体系下反应流出物系统化学离子-平衡模型,并通过工艺过程关联分析和数值模拟分析相结合的方式,对系统内铵盐结晶腐蚀风险进行评估。计算结果表明,空冷器存在NH 4Cl腐蚀风险,结晶温度为169~187℃,且铵盐结晶速率随着温度降低不断增加,极限工况下为0.22 kg h。空冷器对流换热模型通过组分运输方程和冷凝模型构建,数值模拟结果表明,随着流动的持续,最大的传质系数(1.52×10^(-4)m s)和腐蚀速率(0.43 mm a)出现在出口集合管底部。展开更多
基金supported by the National Key R&D Program of China(Grant No.2017YFF0210403)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY17E060008)the Talent Project of Zhejiang Association for Science and Development Project of SINOPEC(No.318023-2)
文摘The ammonium salt corrosion is a typical failure mode for the hydrogenation reaction effluent air cooler(REAC) system. In order to investigate the corrosion characteristics in the REAC system, numerical simulations were performed by using the mixture model, the heating transfer model, and the particles tracking model. The results show that the differences between the temperature and the velocity at each cross section of the first-row and second-row tubes are small. The inertia of the particles plays an important role in the particle’s deposition, and the smaller particles distribute more uniformly in the air cooler. However, for larger particles, they prefer falling from the inner side of the vertical elbow, and preferentially depositing at the inlet header and pipes before saturation. In the heat exchanger tubes, the particle deposition number is larger in the second-row tubes than that in the first-row tubes, and the high-risk tubes mainly concentrate on the middle and right side of the air cooler. The kinetic parameters of the particles are in accordance with the blocking-prone position in many real operating conditions.
文摘渣油加氢装置因原料劣化腐蚀性强,设备长期处于极端运行工况下,导致冷换设备铵盐腐蚀性风险大。以沸腾床渣油加氢系统空气冷却器(简称空冷器)为研究对象,采用NRTL-RK模型构建多组分体系下反应流出物系统化学离子-平衡模型,并通过工艺过程关联分析和数值模拟分析相结合的方式,对系统内铵盐结晶腐蚀风险进行评估。计算结果表明,空冷器存在NH 4Cl腐蚀风险,结晶温度为169~187℃,且铵盐结晶速率随着温度降低不断增加,极限工况下为0.22 kg h。空冷器对流换热模型通过组分运输方程和冷凝模型构建,数值模拟结果表明,随着流动的持续,最大的传质系数(1.52×10^(-4)m s)和腐蚀速率(0.43 mm a)出现在出口集合管底部。
