Transformation of CH4 and liquid fuels into syngas on monolithic catalysts

Active components comprised of fluorite-like Ln_x(Ce_0.5Zr_0.5)_1−xO_2−y (Ln = La, Pr, Sm) and perovskite-like La_0.8Pr_0.2Mn_0.2Cr_0.8O₃ mixed oxides and their composites with yttria-doped zirconia (YSZ) promoted by precious metals (Pt, Ru) and/or Ni were supported on several types of heat-conducting substrates (compressed Ni-Al foam, Fecralloy foil or gauze protected by corundum layer, Cr-Al-O microchannel cermets, titanium platelets protected by oxidic layer) as well as on honeycomb corundum monolithic substrate. These structured catalysts were tested in pilot-scale reactors in the reactions of steam reforming of methane, selective oxidation of decane and gasoline and steam/autothermal reforming of biofuels (ethanol, acetone, anisole, sunflower oil). Applied procedures of supporting nanocomposite active components on monolithic/structured substrates did not deteriorate their coking stability in real feeds with a small excess of oxidants, which was reflected in good middle-term (up to 200 h) performance stability promising for further up-scaling and long-term tests. Equilibrium yield of syngas at short contact times was achieved by partial oxidation of decane and gasoline without addition of steam usually required to prevent coking. For the first time possibility of successive transformation of biofuels (ethanol, acetone, anisole, sunflower oil) into syngas at short contact times on monolithic catalysts was demonstrated. This was provided by a proper combination of active component, thermal conducting monolithic substrates and unique evaporation/mixing unit used in this research.     

Gasoline-range hydrocarbon synthesis over Co/SiO2/HZSM-5 catalyst with CO2-containing syngas

Selective synthesis of gasoline-range hydrocarbons (C₅-C₁₂) was investigated in a fixed-bed micro reactor using two series of CO₂-containing syngas with various mole CO₂/(CO + CO₂) and H₂/(CO + CO₂) ratios, where Fischer-Tropsch synthesis(FTS) and in situ hydrocracking/hydroisomerization were performed over bifunctional Co/SiO₂/HZSM-5 catalyst. CO₂ was converted at 0.15-0.55 of CO₂/(CO + CO₂) ratio under H₂-rich condition (H₂/(CO + CO₂) = 2.0), highest conversion of 20.3% at 0.42. Further increasing CO₂ content decreased CO₂ conversion and quite amount of CO₂ acted as diluting component. For the syngas with low H₂ content or H₂/(CO + CO₂) ratio(< 1.85, H₂/CO = 2.0), the competitive adsorption of CO, H₂ and CO₂ resulted in low CO, CO₂ and total carbon conversion, which was 57.9%, 12.7% and 31.4% respectively at 0.74 of H₂/(CO + CO₂) ratio(H₂/CO/CO₂/N₂ = 40.8/20.4/34.8/4). FTS results indicated that high H₂ content and proper H₂/(CO + CO₂) ratio were favorable for the conversion of CO₂-containing syngas. More than 45% selectivity to gasoline-range hydrocarbons including isoparaffins was obtained under the two series of syngas. It was also tested that the catalytic activity of Co/SiO₂/HZSM-5 kept stable under CO₂-containing syngas(< 7.5%). And the quick catalytic deactivation under high CO₂ containing syngas(H₂/CO/CO₂/N₂ = 45.3/23.2/27.1/3.06) was due to carbon deposition and pore blockage by heavy hydrocarbon, tested by thermal gravimetry, N₂ physisorption and scanning electron microscopy(SEM).     

草酸二甲酯加氢制乙醇酸甲酯反应网络分析及其多相加氢催化剂研究进展

乙醇酸甲酯（MG）官能团丰富,是一种重要的精细化工中间体,而且经过缩聚反应可制得新一代可生物降解材料聚乙醇酸。采用合成气经草酸二甲酯（DMO）加氢路线可实现MG的规模化制备,而该技术工业化的关键是高性能加氢催化剂的开发,当前DMO加氢制MG催化剂正处于工业化前期阶段。本文分析了DMO加氢反应网络及各特征反应的热力学特点,重点概述了DMO多相加氢制MG催化剂的研究进展,包括铜基催化剂、银基催化剂、非铜/银基催化剂等,基于网络特点分析了各催化剂的研究重点及存在的难题,并从反应工艺控制、催化剂载体设计、助剂及活性组分选择等角度提出了改善工业化催化剂开发及性能的思路,建议近期将改性复合载体负载的铜基催化剂,或以银、镍等为第二助剂的复合铜基催化剂作为重点攻关方向,远期将新型非贵金属体系作为储备方向,期望能为开发我国自主知识产权的工业化催化剂提供有益参考。     

Gasification of heavy fuel oils: A thermochemical equilibrium approach

Combustion of heavy fuel oils is a major source of production of particulate emissions and ash, as well as considerable volumes of SO_x and NO_x. Gasification is a technologically advanced and environmentally friendly process of disposing heavy fuel oils by converting them into clean combustible gas products. Thermochemical equilibrium modeling is the basis of an original numerical method implemented in this study to predict the performance of a heavy fuel oil gasifier. The model combines both the chemical and thermodynamic equilibriums of the global gasification reaction in order to predict the final syngas species distribution. Having obtained the composition of the produced syngas, various characteristics of the gasification process can be determined; they include the H₂:CO ratio, process temperature, and heating value of the produced syngas, as well as the cold gas efficiency and carbon conversion efficiency of the process. The influence of the equivalence ratio, oxygen enrichment (the amount of oxygen available in the gasification agent), and pressure on the gasification characteristics is analyzed. The results of simulations are compared with reported experimental measurements through which the numerical model is validated. The detailed investigation performed in the course of this study reveals that the heavy oil gasification is a feasible process that can be utilized to generate a syngas for various industrial applications.     

煤浆浓度提高对气化装置的影响及经济性评价

介绍了煤浆浓度提高对多喷嘴水煤浆加压气化装置的影响。通过对提浓前、后煤浆浓度、黏度、添加剂消耗、有效气成分、炉温等各工艺参数的变化进行对比，进而对有效气产量、甲醇产量、比氧耗等影响作进一步分析。在此基础上，对煤浆提浓后对经济效益的影响进行了评价，为进一步优化工艺控制、提高经济效益提供依据。     

合成气洗涤塔的腐蚀分析与防范措施

介绍了壳牌煤气化装置中合成气洗涤塔的碱腐蚀、氯离子腐蚀的情况以及处理方法.     

Effect of various coal gas contaminants on the performance of solid oxide fuel cells: Part III. Synergistic effects

The coal-derived gas from a coal gasifier contains multiple contaminants, and their synergistic effects may not be simply the additive influences of individual contaminants. The present work presents the results of a study of the synergistic effects of four contaminants of major concern—S, As, P, and Cl, at the ppm level and in combinations of two, three, or four kinds—on the performance of Ni-YSZ/YSZ/LSM solid oxide fuel cells. The results indicate that both cell performance and morphology differ significantly in cells exposed to a single contaminant, and that cell performance is not simply the additive influence of each contaminant. Synergistic effects can be very destructive (accelerated degradation or even cell failure) when S is in the presence with As/P, but can also be beneficial (stabilization in power density variations over time or a slowed degradation rate) when Cl is present with other contaminants. Cl can even partially restore performance loss when it is introduced after P is already present. Therefore, with the addition of Cl the tolerance limit of SOFCs for the other three contaminants can be greatly increased. We speculate that the affinity of the contaminants to Ni catalyst increases in the following order: As < P < Cl. The interactions between and among these contaminants and possible mechanisms for their destructive and beneficial synergistic effects are discussed.     

煤基费托合成尾气流向变换自热式转化制合成气

提出了一种将热交换与反应相结合的流向变换自热反应器用于煤基费托合成尾气转化制合成气。反应器的进料分中间和旁路两处,采用蓄热式换热法回收高温重整气显热用于预热旁路进料。Aspen Plus拟稳态模拟结果表明:调整氧气与费托合成尾气流量比可以得到最大合成气收率,水蒸气从旁路加入能提高甲烷转化率与合成气收率;相比传统的自热重整反应器,它可以使氧耗降低约26%,同时合成气收率增加约9%。有效能分析发现该反应器可以减少反应过程的化学有效能损失。     

The effect of coal syngas containing HCl on the performance of solid oxide fuel cells: Investigations into the effect of operational temperature and HCl concentration

The performance of solid oxide fuel cells (SOFCs) using simulated coal-derived syngas, with and without hydrogen chloride (HCl), was studied. Electrolyte-supported SOFCs were tested potentiostatically at 0.7 V at 800 and 900 °C with simulated coal syngas containing 0, 20, and 160 ppm HCl. The results from the tests without HCl show good performance with little degradation over 100 h of operation. Both 20 and 160 ppm HCl were shown to cause performance losses in the SOFCs after injection into the system. Although the tests presented in this paper show that HCl does cause degradation to SOFC performance, the cell performance was recoverable upon the removal of HCl from the fuel. Also recent results from anticipated Integrated Gasification Combined Cycle IGCC warm/hot-gas-cleanup technologies suggest that HCl will be removed to levels that will not cause any significant performance losses in SOFCs.     

天然气转化利用技术的研究进展

主要评述了自1995年以来,全球天然气转化利用商业化技术的重大进展,包括合成气生产、天然气制合成油、含氧化合物生产(主要是甲醇和二甲醚)、甲醇制烯烃。综述了甲烷脱氢芳构化反应制苯、部分氧化制甲醇、氧化偶联制乙烯的研究进展,并对发展我国天然气化工提出建议。