Numerical simulation of micro-mixing in gas–liquid and solid–liquid stirred tanks with the coupled CFD-E-model

The coupled CFD-E-model for multiphase micro-mixing was developed, and used to predict the micro-mixing effects on the parallel competing chemical reactions in semi-batch gas–liquid and solid–liquid stirred tanks. Based on the multiphase macro-flow field, the key parameters of the micro-mixing E-model were obtained with solving the Reynolds-averaged transport equations of mixture fraction and its variance at low computational costs. Compared with experimental data, the multiphase numerical method shows the satisfactory predicting ability. For the gas–liquid system, the segregated reaction zone is mainly near the feed point, and shrinks to the exit of feed-pipe when the feed position is closer to the impeller. Besides, surface feed requires more time to completely exhaust the added H⁺ solution than that of impeller region feed at the same operating condition. For the solid–liquid system, when the solid suspension cloud is formed at high solid holdups, the flow velocity in the clear liquid layer above the cloud is notably reduced and the reactions proceed slowly in this almost stagnant zone. Therefore, the segregation index in this case is larger than that in the dilute solid–liquid system.     

石化企业挥发性有机物无组织排放监测技术进展

无组织排放占石化企业挥发性有机物（VOCs）排放的主导地位,排放点多、面广、量大、分散、无规则,总体表现为大型面源或体积源,监测难度很大。本文评述了点、线和面(通量)等VOCs无组织排放监测技术及应用进展,总结了石化企业VOCs无组织排放监测存在的主要问题与难点,提出了石化企业VOCs无组织排放监测体系及适用监测技术。总体上,石化企业VOCs无组织排放监控存在排放清单质量不高、源头监测及溯源困难、排放烟羽及其迁移扩散途径无定形、厂界等开放空间难以封闭监测、常规监测的时间和空间覆盖有限等问题或技术难点,可复合应用点、线、面及通量监测技术,结合常规离线、实时在线、排放通量、移动快速响应等监测设计,构建覆盖排放与环境影响的多元化、网络化、立体化监控体系。未来石化企业VOCs无组织排放监控将向多层级、智能化和大数据应用发展。     

加氢反应器空间利用率分析及提升技术开发

通过研究影响加氢反应器空间利用率的主要因素,从最大化提高加氢反应器空间利用率的角度出发,开发出提高加氢反应器空间利用率技术,包含提高反应器空间利用率的反应器内构件成套技术和优选异形齿球形催化剂技术。该技术在保障加氢反应器整体效能和运行周期的基础上,使加氢反应器空间利用率提高了10%~23%。其中,新型内构件成套技术,解决了物料分布不均、易出现局部热点的工程放大问题,使反应器空间利用率比传统技术提高5.3%~14.5%;优选的异形齿球形催化剂技术,能够使反应器空间利用率提高4.7%~8.5%,提高原料油加工量,经济效益十分显著。     

焙烧气氛和孔结构对加氢脱金属催化剂性能的影响

采用饱和浸渍法、在不同焙烧气氛（空气、氮气、水蒸气）下制备了三种加氢脱金属Mo-Ni催化剂,并考察了焙烧气氛对催化剂脱金属、脱硫和脱残碳的影响,研究结果表明：焙烧气氛对加氢脱金属反应的活性影响不大,而空气气氛下焙烧的催化剂表现出相对较高的加氢脱硫和脱残碳活性。进一步考察了氧化铝孔结构对催化剂加氢脱金属性能的影响,并结合数值模拟计算,发现最可几孔径为22 nm的催化剂更有利于加氢脱金属过程的反应-扩散平衡,从而表现出较高的加氢脱金属性能。     

D2H2 equilibration over γ-irradiated zeolites

D₂H₂ equilibrium was studied at 77 and 298 K over HY, AIHY, HZSM-5 and Al_xO_yHZSM-5 which had been γ-irradiated at 77 and/or 298 K. The exchange rate was found to be higher at the lower temperature regardless of the temperature of irradiation. Moreover, at 77 K the exchange rates were similar and more stable over the individual zeolites than at 298 K, thus indicating a common reaction path at 77 K. The exchange rate at 298 K depended on the zeolite type: it was more stable and higher over HZSM-5 than over HY, and extra-lattice Al increased both these properties on HY as well as on HZSM-5. The reaction mechanism is discussed in connection with the nature of defects generated by γ-irradiation.     

Influence of Ce3+ and Pt2+ ions on the reducibility and dispersion of Cu in copper-exchanged Y zeolites

The influence of small additions of Ce³⁺ and Pt²⁺ ions on the reducibility and dispersion of Cu in CuNaY zeolite was examined. The presence of Ce³⁺ ions in CuNaY zeolite during reduction by hydrogen increased the degree of Cu²⁺ reduction, forming Cu⁰ which occured as very small clusters. The addition of a small amount of platinum also increased the degree of reduction of Cu²⁺ ions, but the copper then formed large crystallites (20–30 nm). When Ce³⁺ and Pt²⁺ ions are present simultaneously, platinum has controlling influence on the reducibility and dispersion of Cu⁰.     

塔河沥青质亚组分分离及表征

采用甲苯-正庚烷法将塔河沥青质(TA)分离成重组分(TA1)和轻组分(TA2),使用扫描电镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱法(FT-IR)和核磁共振氢谱(1H-NMR)等方法对TA、TA1和TA2进行表征,分析其表面形态、晶体结构和官能团结构等组成和结构信息.结果表明,TA具有较少的长链结构,侧链...     

弗罗里硅土处理低质量浓度氨氮废水研究

利用弗罗里硅土吸附脱除石化低浓度废水中的氨氮。分别采用BET、SEM及XRF对弗罗里硅土进行表征。考察剂液比、吸附时间、pH、吸附温度及氨氮初始质量浓度等因素对吸附脱除氨氮效果的影响。结果表明,在氨氮初始质量浓度为50.00 mg/L、剂液比为2 g/L、pH为7、吸附温度为293.15 K和吸附时间为5 min的条件下,氨氮去除效果最佳;在此条件下处理石化低质量浓度氨氮废水,氨氮质量浓度从17.53 mg/L降至5.16 mg/L,去除率达到70.6%,满足GB 31570-2015的排放标准。