煤化工工艺过程CO_2排放分析及其减排技术

分析了煤化工产业中煤制甲醇、煤直接液化和间接液化、煤制烯烃等工艺过程中CO_2的排放,并介绍了3种CO_2减排技术:CO_2收集和储存技术、CO_2循环利用技术和CO_2化学转化技术。应高度重视CO_2化学转化技术的开发,把CO_2化学转化为附加值高的化学品。     

减碳排放新技术研发进展与应用

介绍了国内在CO2减排方面开展的研究工作、取得的最新进展及应用现状与前景。     

燃煤电厂烟气中二氧化碳的减排技术

由于CO2等温室气体引发的温室效应对全球生态环境和社会经济发展造成了显著影响,使得CO2减排受到了国际社会的密切关注。文章针对CO2的集中排放源,介绍燃煤电厂烟气中CO2减排技术路线和目前国际上常用的CO2捕集分离技术,最后分析和展望CO2捕集分离技术的发展前景。     

高纯液态二氧化碳的生产技术和设备

生产高纯液态CO2是近几年开发的新技术。针对当前许多化工厂蒸馏塔产生的大量高浓度CO2气体的合理利用，介绍了高纯液态CO2的生产技术及主要设备特点，供该项技术的推广运用、渐臻完善参考。     

绿色碳减排途径探讨

提出了经济发展的源头、过程和终端全系统进行绿色碳减排的方案。通过开发和选择低碳原料和工艺,从源头上避免产生CO2排放;从开采、生产和终端消费全过程节能降耗,从过程中减少CO2排放;对于低CO2浓度废气进行异地生物固碳、高CO2浓度废气就地捕集利用,发展生物质能和改良土壤增强碳汇,加快碳循环和碳固定,消除终端CO2过剩和累积,从而实现可持续的碳减排,维持自然界碳氧循环平衡,同时兼顾解决国家能源安全、粮食安全、环境安全、保护耕地与城镇化、以工哺农、“三农”问题等,满足我国今后较长时间的低碳发展需求。     

Staging of the Fischer‐Tropsch Reactor with a Cobalt‐Based Catalyst

A method for systematic reactor design, described by Hillestad [1], is applied to the Fischer‐Tropsch synthesis. The reactor path is sectioned into stages and design functions are optimized to maximize an objective function. Two different objective functions are considered: the yield of wax and a measure of the profitability. With the chosen kinetic model [2] and the path temperature constrained by 240 °C, staging of the Fischer‐Tropsch synthesis based on the first criteria will increase the yield of wax. By introducing the cost of heat transfer area in the objective function, the total heat transfer area requirement of a two‐stage reactor is significantly less than of a single‐stage reactor.     

制氢尾气提取二氧化碳新工艺

通过对天然气制氢尾气提取二氧化碳的方案选择、工艺论述,说明本工艺在实际生产运行当中是可行的,既节约了能源,又降低了成本。同时提高了产品的附加值。     

Intrinsic and Effective Kinetics of Cobalt‐Catalyzed Fischer‐Tropsch Synthesis in View of a Power‐to‐Liquid Process Based on Renewable Energy

The production of liquid hydrocarbons based on CO₂ and renewable H₂ is a multi‐step process consisting of water electrolysis, reverse water‐gas shift, and Fischer‐Tropsch synthesis (FTS). The syngas will then also contain CO₂ and probably sometimes H₂O, too. Therefore, the kinetics of FTS on a commercial cobalt catalyst was studied with syngas containing CO, CO₂, H₂, and H₂O. The intrinsic kinetic parameters as well as the influence of pore diffusion (technical particles) were determined. CO₂ and H₂O showed only negligible or minor influence on the reaction rate. The intrinsic kinetic parameters of the rate of CO consumption were evaluated using a Langmuir‐Hinshelwood (LH) approach. The effectiveness factor describing diffusion limitations was calculated by two different Thiele moduli. The first one was derived by a simplified pseudo first‐order approach, the second one by the LH approach. Only the latter, more complex model is in good agreement with the experimental results.     

Extraction of Contamination of Automotive Gas Tank Material by Extrusion with Supercritical Carbon Dioxide

During their working life, plastics can be exposed to contaminating media which limit their recyclability. A continuous extraction process with supercritical CO₂ has been developed. Contaminated material is extruded through two twin‐screw extruders in a cascade. The first extruder purifies with scCO₂ and the second extruder is for degassing and hot‐cut pelletisation. Post‐consumer automotive diesel fuel tank material has been processed. A direct flow and a counter‐flow process with different screw configurations have been developed. Characterisation has been performed by headspace gas chromatography. Results show that contaminants were extracted out of the plastic for both process variants. However, direct flow yielded better extraction efficiency.

     

Liquid Carbon Dioxide as Anti‐Solvent Coating Aluminum Hydride

This paper presents a novel surface coating to resolve the serviceability, stability, compatibility, and dehydrogenation of aluminum hydride (alane) using liquid carbon dioxide as an anti‐solvent, dispersant, drying medium, and inert atmosphere. The coated alane sample was characterized by SEM, XPS, XRD, and FT‐IR spectroscopy. The coating agent was uniformly applied on the surface of alane and the crystalline phase remained unchanged. The alane molecules became more stable after coating. The thermal stability of alane before and after coating was analyzed by DSC. The enthalpy of the coated alane increased under different heating rates, indicating increased thermal stability. The lower electric spark sensitivity of the coated alane showed improved serviceability and stability. The method developed in this study may be suitable for coating other hydrogen storage and energetic materials.     

苯酚和二氧化碳合成碳酸二苯酯的热力学分析

根据经典热力学原理,计算了苯酚和二氧化碳合成碳酸二苯酯的反应在不同温度下的摩尔吉布斯自由能变化。结果表明,高温有利于碳酸二苯酯的生成;提高二氧化碳压力对平衡有利;计算结果与实验数据吻合,但实验收率偏低。     

Mixing from Fickian diffusion and natural convection in binary non‐equilibrium fluid phases

A two‐dimensional (2‐D) model that describes mass transport between non equilibrium gas and liquid phases of a binary non polar mixture in a closed system of fixed volume and temperature is presented. Diffusion, convective mass transport due to compressibility and non ideality, and the motion of the interface upon evaporation and dissolution are accounted. Natural convection in both phases is incorporated, which allows to study the effect of density increase in the liquid phase from gas dissolution. The Peng‐Robinson equation of state is used to calculate the densities and the fugacities needed to find the interfacial composition consistent with local chemical equilibrium. The results obtained with a one‐dimensional model was compared to our 2‐D results, showing that natural convection influences the mixing time drastically. In the liquid bulk phase, convective flux is much higher than diffusive flux. Across the interface, diffusive flux is, however, the dominating flux, which allows accurate measurement of diffusion coefficients at high pressure in 2‐D domains. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Palladium Supported on an Acidic Resin: A Unique Bifunctional Catalyst for the Continuous Catalytic Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide

1% Palladium‐doped acidic resin (Amberlyst^® 15; styrene‐divinylbenzene matrix with sulfonic acid groups) is shown to be a highly active catalyst for the continuous catalytic hydrogenation of CC bonds in supercritical carbon dioxide (scCO₂) without affecting CO bonds. This 1% Pd/Amberlyst‐15 catalyst promotes the industrially important selective formation of 2‐ethylhexanal from crotonaldehyde in a “one‐pot” pathway involving hydrogenation and aldol condensation with a number of merits. The selectivity behavior of 1% Pd/Amberlyst‐15 is strikingly different compared to that of 1% Pd/C and 1% Pd/Al₂O₃ due to its prominent bifunctional nature based on sulfonic acid groups adjacent to metallic Pd sites. Hybrid “[Pd_n–H]⁺” sites are suggested to act as both metal and acid sites promoting the bifunctional catalysis.     

在超细催化剂CuO/ZnO/SiO_2上CO_2加氢合成甲醇的优化研究

本文考察了焙烧温度、还原温度、反应温度、反应压力和体积空速对用于ＣＯ２加氢反应的超细ＣｕＯ／ＺｎＯ／ＳｉＯ２催化剂性能和产物分布的影响，确定了催化剂的合适焙烧温度、还原温度，并对ＣＯ２加氢反应条件进行了优化