一氧化碳变换催化剂的应用与发展

介绍了CO变换催化剂的发展背景,对国内外CO高温变换催化剂和低温变换催化剂进行,综述。通过比较,发现高效节能型变换工艺将是变换工艺的发展方向,开发低温、高活性和稳定性的变换催化剂将相应成为研究的主要目标。     

低汽化比CO低温变我催化剂进展及B207的工业应用

介绍了国内外CO低温变换催化剂发展趋势，着重阐述了南化集团研究院研制开发的新型CO低温变换催化剂B207在中原大化集团有限责任公司及安阳化工集团的应用情况。     

铜基CO低温变换催化剂的研究进展

铜基CO低温变换催化剂是合成氨,制氢厂最关键的经济型催化剂.详细介绍了铜基CO低温变换催化剂近年来的发展概况,指出开发低温、高活性和选择性,热稳定性好,堆积密度低,易于还原,还原后体积收缩率低,抗毒性能好的长寿命催化剂,尤其是开发预还原型低变催化剂是今后国产低变催化剂研制开发的趋势.     

铜基低变催化剂H_2S中毒机理热力学分析

为掌握CO变换制氢过程中催化剂中毒机理,采用热力学非均相反应体系中G ibbs自由能最小原理,分析了铜基低温变换催化剂在463.15—523.15 K内H2S中毒过程中可能发生的化学反应及其产物,并结合文献实验结果综合讨论了铜基低温变换催化剂的H2S中毒机理。结果表明:催化剂的H2S中毒过程中,硫酸盐和积碳会造成催化剂的暂时性中毒,生成Cu2S和CuS化合物造成永久性中毒;O2的存在会加快催化剂的中毒反应;铜基低温变换催化剂不适合用于含高体积分数CO原料气的变换反应过程。     

CO变换催化剂的研究进展

介绍了国内外CO中(高)温变换催化剂、低变催化剂及耐硫变换催化剂的现状及研究进展。高效节能型变换工艺将是变换工艺的发展方向,开发低温、高活性和稳定性的变换催化剂将相应成为研究的主要目标。     

金催化剂及其在化工中的应用研究进展

系统地介绍了影响金催化剂催化活性的因素,论述了金属金催化剂在CO低温氧化、CO的选择性氧化、低温水气变换、甲醇的部分氧化、苯乙烯环氧化和葡萄糖的选择性氧化等反应中的研究进展,分析了今后金催化剂的研究重点。     

LB205型CO低温变换催化剂的研制开发

介绍了新型CO低温变换催化剂的研制情况。研制的LB205型低温变换催化剂在压力≤5．0MPa，温度185-250℃．汽／气比0．2～0．6．干气空速1000～4000h^-1．干气中CO体积分数2．5％～4．0％．CO2体积分数16％～19％．余量为H2＋N2条件下，催化剂CO变换率≥95％，400℃耐热2h后CO变换率≥93％。满足工厂对低变催化剂的要求．尤其适合在节能型合成氨厂的低汽／气比条件下使用。     

国产低温变换催化剂在节能流程氨厂的使用

本文介绍了几种用于节能流程大型氨厂低温变换催化剂主要性能及其使用情况,表明国产低温变换催化剂具有低温活性好、CO转化率高、选择性好、使用寿命长等优点,完全可以满足国内节能流程合成氨厂的使用要求。     

CB-9型低变催化剂在中小氮肥厂的应用

合成氨厂所用7种催化剂中,转化、变换、合成催化剂最为重要,变换催化剂尤其是低变催化剂性能的优劣对工厂的经济效益起着至关重要的作用,这对抗风险能力稍弱的中小氮肥企业来说更加重要.而CO的最终变换率取决于低温变换催化剂的性能和适应能力,要求低变催化剂具有较高的活性和稳定性,以便在较低温下使反应达到平衡.实践证明：低变炉出口CO含量降低0.1％,氢气和氨产率可增加1.1％ ～1.6％.     

LB205型低温变换催化剂的工业应用

介绍了LB205型低温变换催化剂升温还原和工业运行情况.实际应用证明:该催化剂具有低温活性好、CO转化率高的特点,在进口气体中含CO体积分数为3.1%～3.6%的情况下,出口气体中含CO体积分数为0.15%～0.18%,CO转化率＞94%,完全满足生产工艺对低变催化剂的要求.     

低密度一氧化碳低温变换催化剂的研究

在国产铜系一氧化碳低温变换催化剂基础上,进行了降低堆密度和副产甲醇量的研究,通过对制备催化剂技术路线的研究,选择了组成为铜、锌、铝氧化物的混合物,Cu/Zn为1.0~1.8时催化剂综合性能较好,考察了制备的低密度催化剂的活性、耐热性和甲醇的生成量,并与现有工业催化剂进行了对比,结果表明本研究的低变催化剂性能达到了较先进的技术指标,能够在低水碳比条件下使用。     

全低变系统偏温问题分析及预防措施

主要介绍了天脊集团高平化工有限公司的全低变工艺及该工艺系统自开车以来的运行、改造情况,对变换炉出现的偏温现象及造成的原因进行了分析,提出了预防措施。     

全低变,联醇工艺对调节氢氮比的干扰及对策

变换改为全低变后，变换出口ＣＯ含量不稳定、联醇进行负荷调整对造气调节合成氢氮比产生了较大的干扰作用，影响合成氨的稳定生产。本文利用高科技波谱规律分析方法进行调节，将全低变ＣＯ、联醇负荷输入微机系统，调节氢氮比，达到提高合成氨产量的目的。     

LB205低温变换催化剂的研制开发

介绍了新型CO低温变换催化剂的研制情况。研制的LB₂0₅型低温变换催化剂在≤5.0 MPa、温度185～250 ℃、V(汽)／V(气)=0.2～0.6、干气空速1 000～4 000 h^－1、干气中CO 体积分数2.5%～4.0％、CO₂体积分数16%～19％和余量为H₂+N₂条件下,催化剂CO变换率≥95％,400 ℃耐热2 h后CO变换率≥93％。满足工厂对低变催化剂的要求,尤其适合在节能型合成氨厂的低汽/气条件下使用。     

天然气制氨一次变换炉设计

一次等温ＣＯ变换是合并传统的中低和低变为一次变换工艺，总结介绍在泸县化肥厂的生产实践经验，ＣＢ－２催化剂的优良性能，一次变换炉结构优化及推广应用前景。     

Effect of varying proportions of dietary menhaden and corn oil on experimental rat mammary tumor promotion

Dose-related effects of long-chain highly unsaturated n−3 fatty acids on the development ofN-nitrosomethylurea (NMU)-induced rat mammary tumors were assessed in female F344 rats. Four test groups (36 rats/group) were fed the following high-fat (HF) diets (23% fat, w/w): Group 1, 18% menhaden oil (MO) and 5% corn oil (CO); Group 2, 11% MO and 11.8% CO; Group 3,5% MO and 18% CO; Group 4, CO alone. A fifth group, serving as an internal control, was fed a low-fat diet containing 5% CO alone. Experimental diets were begun after initiation with NMU, and the experiment was terminated 31 wk later. Total tumor numbers in the five groups were 28, 16, 32, 26 and 11, respectively, indicating that the promotion phase of NMU-induced carcinogenesis was significantly suppressed only when equal parts of CO and MO (Group 2) were fed or when CO alone was fed at 5% (w/w). At high (Group 1) or low (Group 3) levels of MO, tumor numbers were indistinguishable from the HF CO group (Group 4). The same pattern was observed when assessed in terms of cumulative tumor incidence and multiplicity. However, when expressed in terms of final tumor incidence, dietary MO did not suppress tumor promotion in a statistically significant fashion at any concentration. Animals fed MO gained weight at the same rate as those fed CO, indicating that the presence of MO in the diet did not result in food avoidance behavior. Measurement of total serum cholesterol indicated an inverse trend with respect to the MO content of the diet. Analysis of serum fatty acid profiles indicated that the proportion of n−3 and n−6 polyun-saturated fatty acids (PUFA) in the serum reflected that of the diet. These results support the hypothesis that the relative proportions of dietary n−3/n−6 fatty acids play an important role in the suppression of experimental mammary tumorigenesis and suggest that changes in circulating cholesterol or n−3 PUFA levels, induced by dietary MO, are not directly related to tumor development. Presented in part at the 81st Annual Meeting of the American Association for Cancer Research, Washington, D.C., May 1990     

Development of iso-octane fuel processor system for fuel cell applications

An iso-octane fuel processor system with three different reaction stages, autothermal reforming (ATR) reaction of iso-octane, high temperature shift (HTS) and low temperature shift (LTS) reactions, was developed for applications in a fuel cell system. Catalytic properties of the prepared Ni/Fe/MgO/Al₂O₃ and Pt–Ni/CeO₂ or molybdenum carbide catalysts were compared to those of commercial NiO/CaO/Al₂O₃ and Cu/Zn/Al₂O₃ catalysts for ATR and LTS reaction, respectively. It was found that the prepared catalysts formulations in the fuel processor system were more active than those of the commercial catalysts. As the exit gas of iso-octane ATR over the Ni/Fe/MgO/Al₂O₃ catalyst was passed through Fe₃O₄–Cr₂O₃ catalyst for HTS and Mo₂C or Pt–Ni/CeO₂ catalyst for LTS reaction, the concentration of CO in hydrogen-rich stream was reduced to less than 2400 ppm. The results suggest that the iso-octane fuel processor system with prepared catalysts can be applied to PEMFC system when a preferential partial oxidation reaction is added to KIST iso-octane reformer system.     

煤基甲醇装置CO变换超温原因及对策

河南煤业化工集团中原大化公司甲醇装置CO变换采用三段变换工艺,2008年投入运行后,第一变换炉超温严重,影响了系统的正常运行,增加了消耗。通过分析造成超温的原因,分步整改,最终使问题得到了有效解决,取得了良好的经济效益。     

LTS型、TTS型三螺杆挤出机与双螺杆挤出机的比较

从机械设计角度,对石家庄德倍隆科技有限公司生产的LTS型、TTS型三螺杆挤出机与双螺杆挤出机进行了比较。指出LTS和TTS型三螺杆挤出机操作范围更宽,混炼能力更强,能够降低能耗,能满足新材料对混合效果不断提高的要求。     

CO2吸收塔腐蚀现象及原因分析

ＣＯ_２吸收塔腐蚀现象及原因分析任永祥（川化集团有限责任公司第二化肥厂，成都，６１０３０１）１９９４年１２月在对ＣＯ２吸收塔进行压力容器定期检验时，发现该塔下塔底部的气体进口分布器与最下层填料支撑之间塔壁发生了较严重的冲刷腐蚀现象。经过１９９５年一年?..