催化裂化干气中乙烯的回收工艺研究进展

介绍了国内外各种催化裂化干气中乙烯的回收工艺和发展状况,分析了其特点和适应性。同时,结合我国目前干气中乙烯回收的现状,基于吸附分离和吸收分离的各种优势提出了一种浆态吸收法新工艺,此工艺既解决了吸附法的连续性问题,又解决了吸附分离的稳定性问题,为乙烯的回收提供了新的思路。     

环氧乙烷装置排放气中乙烯的回收

讨论了环氧乙烷装置排放气的组成及其对氧化反应的影响，提出了对乙烯进行回收的工艺技术要求，分析比较了国内外不同回收工艺包括变压吸附、膜分离、吸附分离等技术的发展概况，提出变压吸附技术由于工艺简单，适应性强，是一种较有发展前景的回收工艺。     

吸附富集的石脑油中正构烷烃裂解制烯烃经济效益分析

为了集成优化利用石脑油资源,使乙烯裂解和催化重整工艺得到合理的原料调配,运用5A分子筛吸附分离技术将石脑油中的正构烷烃分离.富含非正构烃的吸余油作为优质催化重整原料或高辛烷值汽油调合组分,富含正构烷烃的脱附油作为优质蒸汽裂解制乙烯原料.在工业典型操作条件下,与以石脑油为原料的乙烯裂解工艺相比,气体收率由84.3%增加到90.8%,乙烯收率增加11～14个百分点,三烯总收率增加8～10个百分点.以90万吨/年乙烯装置为例进行了以吸附分离脱附油和石脑油共同作为裂解原料的石脑油部分吸附分离加工方案的经济效益分析.     

石脑油吸附分离组分的经济收益分析

文章采用5A分子筛为吸附剂的固定床吸附分离技术将石脑油组分分离,得到较优化工艺条件:压力为0.5 MPa、温度为300℃,对分离得到的脱附油和吸余油等几种油样在乙烯和重整方向分别进行了经济收益的分析,乙烯收率和重整效益增加明显,数据详实可靠,为工业设计提供了参考。     

变压吸附在乙烯装置氢气分离中的应用

介绍了变压吸附的分离原理及变压吸附技术在乙烯装置中分离氢气的应用．成功的分离出了高纯度氢气产品。     

轻质烯烃-烷烃分离新工艺开发进展

介绍了用于乙烯、丙烯等轻质烯烃与相应烷烃分离的化学吸收、吸附和膜分离等新工艺。评价了膜分离法具有分离因子高、能耗低、清洁、环保特点,但膜的稳定性还有待改进,膜材料的价格较昂贵;认为膜与蒸馏相结合的复合分离技术具有潜在的工业应用价值。     

变压吸附回收高纯乙烯的工艺模拟

石化装置的烯烃尾气存在无法回收的情况，利用变压吸附过程可以实现烯烃尾气的回收。为得到较高浓度的乙烯回收产品，创造更高的经济价值，应用Aspen Adsorption吸附模拟软件，对乙烷、乙烯吸附过程建模。经过实验验证，模型可以准确提供实验参考，从而减轻变压吸附过程对实验的完全依赖。面向乙烯回收的工艺过程，应用软件对工艺操作参数进行了模拟，得到了高纯度的乙烯回收产品，从机理上验证了方案的技术可行性。     

变压吸附技术在MTO脱甲烷系统中的应用性分析

针对目前Lummus和惠生的MTO烯烃分离工艺都存在尾气中乙烯损失量大,吸收剂循环量大和分离能耗高等缺陷,利用Aspen Plus 软件模拟计算了两种降低能耗成本的改进流程.本研究通过在脱甲烷系统中引入变压吸附装置,形成吸附-精馏的耦合,提高乙烯总收率的同时达到降低能耗的目的.     

乙烯-乙烷分离吸附剂的研究进展

对吸附法分离乙烯的研究作了综述 ,分析了不同的乙烯吸附剂及其吸附性能。     

三维KIT-6分子筛对乙烯乙烷吸附分离的研究

采用水热法合成三维KIT-6分子筛,以KIT-6为载体,采用等体积浸渍法负载Ag NO3制备乙烯/乙烷分离的π络合吸附剂,通过氮气吸附脱附、X射线衍射和X射线能谱分析对吸附剂进行表征,采用自制设备测定了π络合吸附剂的乙烯乙烷吸附等温线和乙烯吸附动力学曲线,相应的乙烯乙烷吸附热用克劳修斯-克拉伯龙方程求得。结果表明,Ag NO3最佳负载量为29%,在303.15 K、0.6 MPa下,络合吸附剂的乙烯吸附量高达47 m L/g,分离系数为3.3,乙烯吸附热值显示乙烯与吸附剂的作用是介于物理吸附和化学吸附之间的π络合吸附,乙烯在络合吸附剂上传质较快,具有一定的应用前景。     

载体对CuCl2-La（NO3）3／AC吸附分离乙烯／乙烷的影响

考察了不同种类的活性炭载体对CuCl2-La（NO3）3/AC吸附剂吸附乙烯性能的影响。通过XRD表征表明,CuCl在4种活性炭上均呈高度分散状态。对吸附剂的比表面、总孔容、微孔孔容和平均孔径测试结果表明,活性炭的平均孔径和微孔孔容大小决定乙烯的吸附量和乙烯／乙烷分离因数大小。活性炭的平均孔径越小,微孔孔容越大,对乙烯的吸附量越大,乙烯,乙烷分离因数越大。以上海椰壳炭为载体的吸附剂因为具有最小的平均孔径和最大的微孔孔容,因此,对乙烯的吸附效果最好。     

CaY分子筛对乙二醇和1,2-丁二醇吸附分离性能的研究

利用装填有CaY分子筛的固定床对乙二醇和1,2-丁二醇吸附分离进行研究,从水、甲醇、乙醇和正丙醇中筛选出正丙醇为最佳洗脱溶剂,并探究了进样流速(0.4, 0.8, 1.2 mL/min)及操作温度(298, 318, 338 K)对穿透曲线的影响,对测得的穿透曲线采用Modified Dose-Response模型进行拟合,与实验结果能够高度吻合。并采用巨正则蒙特卡洛(GCMC)研究混合醇在CaY分子筛内部的竞争吸附,模拟了乙二醇和1,2-丁二醇在CaY分子筛内部的吸附位点,发现其吸附位点几乎重合,且CaY分子筛对乙二醇的吸附量要大于1,2-丁二醇,此模拟结果为实验结果提供了微观理论支撑。     

Separation of ethylene/ethane mixtures by adsorption on small-pored titanosilicate molecular sieves

Adsorptive separation of ethylene and ethane may represent a less energy-intensive alternative to current sub-ambient distillation methods. In this approach, ethylene and ethane are separated by inverse-phase gas chromatographic and gravimetric isotherm techniques on ion-exchanged forms of ETS-4 and RPZ titanosilicate molecular sieves. Gas chromatography reveals that kinetic separation of ethylene from ethane is possible using ETS-4 and RPZ adsorbents exchanged with Zn and mixed Ca/H. Gas chromatographic selectivities of 4–40 for the adsorptive separation of ethylene and ethane were measured for these adsorbents, and the limiting selectivity calculated from gravimetric adsorption isotherms was between 4 and 12. In accordance with the ideal adsorbed solution theory, ethylene/ethane selectivity increases with pressure in all cases studied, especially for strontium- and barium-exchanged ETS-4. Due to the molecular sieving character of the adsorbents, steric effects were observed for the adsorption of ethylene and ethane, and contact time between the adsorbent and the gas mixture was the key factor in the separation of the gases. ETS-4 and RPZ materials exchanged with Zn or Ca/H are excellent candidates for the commercial adsorptive separation of ethylene and ethane.     

添加稀土镧对吸附分离乙烯/乙烷的影响

考察了添加稀土镧, 氧化镧、硝酸镧和氯化镧,对载铜活性炭吸附剂分离乙烯/乙烷的影响.测定了乙烯,乙烷40℃吸附等温线.乙烯选择性实验结果表明,氯化镧的添加效果最佳.合适的添加量在11.2%(wt)附近,可使乙烯的选择性提高到原来的两倍以上. 比表面及孔径分布数据表明, 添加适量稀土镧增大了吸附剂孔的比表面和孔体积, 特别是对微孔,因而更有利于提高吸附剂表面的利用率.通过SEM对稀土络合吸附剂的形貌观察可知,稀土分散于未被活性组分CuCl利用的活性炭表面.由于稀土对乙烷吸附量极小,从而极大抑制了活性炭载体对乙烷的物理吸附,这是此复合吸附剂提高乙烯乙烷分离性能的主要原因.     

提高乙二醇紫外线透过率技术进展

介绍了影响乙二醇紫外线透过率的因素，分析了乙二醇产品中的微量羰基化合物杂质是影响其紫外线透过率的主要因素；认为在乙二醇纯化过程中使用吸附、膜分离和添加有关试剂等物理、化学方法可以提高其紫外线透过率。     

催化裂化干气分离丙烯用活性炭吸附剂的特性研究

为了获得可用于催化裂化干气中吸附分离丙烯用的活性炭,选择国内有代表性的不同材质和产地的活性炭,测定了比表面积、孔容、平均孔径和微孔体积等物性参数.在自制的吸附实验装置上,测定了101.3 kPa、40℃下丙烯和乙烯在不同活性炭上的吸附量,比较对丙烯的选择性.结果表明在上述吸附条件下,活性炭AC-1对丙烯的吸附量最大,达3.552 mmol/g,对丙烯的选掸性为1.37.测定了乙烯丙烯二元混合气中,不同丙烯分压下,活性炭AC-1对丙烯和乙烯的吸附量.活性炭AC-1适用于干气吸附分离丙烯过程.     

Shaping of metal-organic frameworks through a calcium alginate method towards ethylene/ethane separation

The separation of ethylene and ethane is a crucial, challenging and cost-intensive process in chemical engineering. Metal-organic frameworks (MOFs) are a class of novel porous adsorbents used for the separation of ethylene/ethane mixtures. However, MOFs are normally crystalline powders that cause multiple problems, such as dust, abrasion and heat/mass loss, as well as significant pressure drops on the adsorption bed resulting in a sudden stop in production. To solve these issues, we have prepared four different sphere-shaped adsorbents, including Mg-gallate, Co-gallate, MUV-10(Mn) and MIL-53(Al) using a calcium alginate method to achieve excellent ethylene/ethane separation performance. The performance of the sphere-shaped adsorbents has been validated using mechanical strength measurements, powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, gas adsorption isotherms and dynamic breakthrough experiments. The excellent mechanical strength of these sphere-shaped adsorbents meets the criteria for industrial application in gas separation. Thus, the energy consumption and operating cost will be further reduced in the ethylene production process. We believe that this shaping method will open a prosperous route to the development of MOFs toward higher technology levels and their commercial application.     

Reverse selectivity of zeolites and metal-organic frameworks in the ethane/ethylene separation by adsorption

Major advances in the ethane/ethylene separation will be related with the discovery of adsorbents that present preferential adsorption of ethane over ethylene. Metal-organic frameworks (MOFs) are crystalline materials consisting of metal ions, or ion clusters, and organic ligands. Gas chromatography (GC) is most informative for materials screening for the ethane/ethylene separation since it needs only few mg of sample and gives selectivity results at various temperatures. This is illustrated by the methodology presented in this work where materials from two types of families (zeolites and MOFs) were used to show the reversed selectivity that can be found towards the ethane/ethylene separation.     

Adsorptive separation of ethylene/ethane mixtures with CuCl@HY adsorbent: equilibrium and reversibility

In this work, we investigate the potential of CuCl-functionalized HY zeolite (CuCl@HY) as an effective adsorbent for the ethylene/ethane separation. The CuCl@HY adsorbents were prepared with CuCl₂ as precursor by a solid-state dispersion method, followed by the activation with CO. The CuCl@HY adsorbents with different CuCl loadings were investigated for ethylene and ethane adsorptions, and evaluated the reversibility for multiple ethylene adsorption/desorption cycles. The experimental results reveal that the optimal adsorbent with copper loadings of 5 mmol/g HY zeolite displays high ethylene adsorption capacity, high C₂H₄/C₂H₆ adsorption selectivity and good reversibility. In addition, the adsorption equilibrium isotherms of ethylene and ethane on CuCl@HY at temperatures up to 333 K can be well correlated by the Sips models, and the corresponding isosteric heats of adsorption are calculated using the Clausius–Clapeyron equation. The value of isosteric heat of adsorption suggests that the interaction of CuCl@HY with ethylene molecules is between physisorption and chemisorption.