氨合成塔使用预还原氨合成催化剂的探讨

预还原氨合成催化剂为制造厂预先将催化剂还原好并进行表面钝化处理等,合成氨厂使用时只需将其表面的钝化部分经简单再还原即可;而传统合成氨生产中使用的氧化态氨合成催化剂并无预先还原的过程,需在氨合成塔内进行整个还原过程。为探究氧化态氨合成催化剂与预还原氨合成催化剂的优劣,从两者的装填、还原过程、活性以及经济性等方面进行对比分析,认为氧化态氨合成催化剂装填较为容易,其还原更需严格控制好各项工艺参数,还原后与预还原氨合成催化剂的活性相差不大;而预还原氨合成催化剂装填需小心谨慎和做好保护等,可明显缩短系统开车时间,节约开车成本,具有明显的经济效益。小型合成氨装置建议使用氧化态氨合成催化剂,大中型合成氨装置推荐全部或部分使用预还原氨合成催化剂。     

山东国昌催化剂有限公司

氨合成催化剂定点生产企业铁系、镍系、铜系催化剂预还原加工基地山东国昌催化剂有限公司是鲁西化工集团所属的高新技术企业,具有得天独厚的生产条件。专业生产氨合成催化剂和预还原催化剂,公司依托南京国昌化工科技有限公司在氨合成领域的技术优势和鲁西化工丰富的管理经验,研究、开发、生产氨合成催化剂及催化剂预还原加工。目前总资     

预还原型氨合成催化剂还原度的分析

对预还原型氨合成催化剂还原度的分析,目前暂无相对准确的方法。介绍了用滴定法测定预还原型氨合成催化剂中的金属铁和总铁的质量分数,二者之比即为预还原型氨合成催化剂的还原度。     

山东国昌催化剂有限公司

<正>氨合成催化剂定点生产企业铁系、镍系、铜系催化剂预还原加工基地山东国昌催化剂有限公司是鲁西化工集团所属的高新技术企业,具有得天独厚的生产条件。专业生产氨合成催化剂和预还原催化剂,公司依托南京国昌化工科技有限公司在氨合成领域的技术优势和鲁西化工丰富的管理经验,研究、开发、生产氨合成催化剂及催化剂预还原加工。目前总资产1300万元,专业技术人员50人。公司现有氧化态氨合成催化剂生产线二     

A301预还原型氨合成催化剂的应用

介绍A301预还原催化剂在建峰化工总厂布朗工艺合成塔中的还原及运行,分析总结该催化剂的使用效果,为以后氨合成催化剂选型提供参考.     

XA201－H－1还原态催化剂的生产制备和工业应用

分析了氨合成氧化态催化剂现场还原的缺点以及预还原催化剂在使用过程中存在的问题;阐述了为解决上述不利因素而研发的还原态催化剂XA201-H-1的还原机理、制备过程以及催化剂的更换、装填方案;工业应用实例表明,该还原态催化剂在提高还原质量、缩短还原时间以及减少原材料、燃料、动力消耗等方面效果明显。     

氨合成催化剂更换总结

总结了氨合成催化剂更换及A110-1H型预还原催化剂升温还原以及运行情况。     

600kt/a合成氨装置氨合成催化剂还原小结

简介河南晋开化工投资控股集团有限责任公司二分公司二期合成氨装置Casale氨合成塔的内件结构、气体流程,针对一期合成氨装置氨合成催化剂还原过程中存在的一些问题,对二期氨合成催化剂升温还原方案及过程控制进行了一些改进,并详细介绍二期氨合成催化剂的装填步骤、升温还原方案及其实际升温还原情况。实践表明,二期氨合成催化剂采用改进方案进行升温还原,还原过程中各项工艺参数均控制在指标范围内,氨合成催化剂使用状况较好。     

新型氨合成催化剂通过鉴定

5月25日，由中德合资辽宁盘锦南方化学辽河催化剂有限公司和浙江工业大学共同研制的新型氨合成催化剂——Amomax-10型氧化型、Amomax-10H型预还原型氨合成催化剂在沈阳通过专家技术鉴定。目前这两种催化剂已经完成了全过程工业化生产。该新型亚铁基氨合成催化剂突破了国际上沿袭了70多年的传统熔铁催化剂的四氧化三铁基体系，在原A301基础上有了实质创新性改进，形成新的专利。新型亚铁基氨合成催化剂氧化型和预还原型产品具有极易还原、催化活性高、低温低压下的高活性和良好的热稳定性，压力与温区宽及抗毒与耐热性能优良、机械强度高等特点。实际应用表明：新型氨合成催化剂完全达到了设计要求，起活温度低，还原时间短。可降低床层阻力，解决了氧化亚铁基催化剂极易还原与大型氨厂还原设施不足的矛盾，节能效果十分明显。     

A110—1H型预还原氨合成催化剂的工业应用

催化剂生产厂采用最佳条件对氨合成催化剂预先进行还原处理，可获得最佳的催化剂活性，并可为氨厂赢得有效的生产时间，经济效益显著。本文拟以小型以及日产千吨的大型氨厂为例，说A110－1H型预还原氨合成催化剂的活化、运转及其经济效益进行分析评价。     

ESTIMATION OF THE EFFECT OF PRODUCT SHRINKAGE ON THE DRYING TIMES,HEAT INPUT AND CONDENSER LOAD OF THE PRIMARY AND SECONDARY DRYING STAGES OF THE LYOPHILIZATION PROCESS IN VIALS

ABSTRACT

The effects of cake shrinkage on the drying times and energy requirements of the primary and secondary drying stages of the freeze drying process involving the drying of a material in a vial, are estimated through the construction and solution of an extended unsteady state and spatially multidimensional model that accounts for the changes introduced by cake shrinkage on the internal and external mass and heat transfer mechanisms of the freeze drying     

6万t/a甲醇装置的增产节能改造

采用二段低压法甲醇合成技术、三塔精馏和高效规整填料对6万t/a甲醇装置进行改造，改造后甲醇产量增幅为675，吨精甲醇综合能耗下降30％，产品质量全部达到GB338－92优等品要求，实践证明改造是成功的。     

Copper and its utilisation in Danish agriculture

Use of copper in modern agriculture needs more and more attention. Copper is used as an additive for feeding stuffs and for fertilizers . Crop uptake of copper is small and when farmers use very copper-enriched slurry, manure or sludge there will be a great positive copper balance in the soil. Under such conditions the copper content of the crops will increase and this can cause toxicity in animals, especially in sheep. The paper reviews the situation in Danish agriculture in particular.     

离体筛选方法在杀虫剂研发中的应用

农药筛选方法在新农药开发中占有重要的地位,与传统的活体筛选方法相比,离体筛选方法具有快速、经济、方便和重复性好等优点.近年来,离体筛选方法在杀虫剂研发中得到了广泛的应用,随着分子生物学和生物技术的发展,新的杀虫剂筛选方法将不断被开发出来.     

注射型原位成型药物传递系统的研究现状

注射型原位成型药物传递系统在近年来得到了广泛关注。注射型原位凝胶植入局部位置并使多聚物以半固体形式贮存药物,这种形式相比其它传统的给药方式具有很多优点。本文重点介绍了原位系统中原位沉淀凝胶的贮药机制,特性及其优缺点。     

A Comparative Study of Water- and Benzene-Saturated Mesoporous Silicas by 1H NMR Spectroscopy

1H NMR investigations have been carried out on water- and benzene-saturated mesoporous sillicas with a wide range of pore sizes (13–42 Å). The freezing point of the bound water increases with the pore size, approaching that of bulk water at large pore sizes. With large pore sizes, there is more than one transition due to the bound water species. The benzene-saturated samples show a behavior similar to that of water-saturated samples, although the freezing point depression is significantly greater. The pore size distribution generally becomes broader with the increase in pore size. The original Kelvin equation is satisfactory to estimate the pore radii both in the case of water and benzene-saturated samples.     

固定床间歇式煤气发生炉系统的增产节能

详细介绍了如何提高煤气发生炉的吹风蓄热效率；适当提高气化层温度，增加蓄热量；采用高热焓的过热蒸汽制气；充分利用加氮蓄热，提高气化效率；采用前吹净方法来增加加氮总量，提高气化效率；合理控制蒸汽流量等技术措施来解决煤气发生炉系统的增产节能等问题。     

The impact of surface science on the commercialization of chemical processes

Surface science developed instruments for atomic- and molecular-scale studies of catalyst surfaces, their composition and structure, both in a vacuum and at high pressures, under reaction conditions (bridging the pressure gap). Surfaces ranging from single crystals, nanoparticles and thin films to porous high surface area catalytic materials have been studied. Classes of surface structure sensitive and insensitive reactions have been identified by surface science studies, including ammonia synthesis, hydrodesulfurization, reforming, combustion and hydrogenation. Rates of reactions often vary by orders of magnitude between using the right and the wrong surface structures. The roles of many promoters that modify the catalyst surface structures and bonding of adsorbates have been verified. Surface reaction intermediates could be identified and the mobility of adsorbates and the adsorbate induced reconstruction of the catalysts attest to the dynamic nature of the catalytic systems during the reaction turnover. The important active sites for catalysis include the low coordination surface step, kink, oxygen and chloride ion vacancies sites and sites at oxide-metal interfaces. Uncovering the molecular ingredients of heterogeneous catalysts will have a major impact on the understanding of reaction selectivity to help the evolution of green chemistry and selective reaction of many types.     

Independent prediction of slip velocity and hold-up in liquid/liquid extraction columns

The correlation of slip velocity using a large bank of published data for pulsed perforated-plate, Karr reciprocating-plate, rotating disc and spray extraction columns is presented. Based on more than 3,700 data points with and without mass transfer, empirical equations not including hold-up for each of the columns are suggested which reproduce the slip velocity data over a wide range of variables. Explicit correlations for hold-up in both the loose and dense-packed regions of operation in spray columns are also presented which do not involve slip velocity. The equations presented are more exact and simpler to use than previous empirical correlations; these often involve the characteristic velocity which is difficult to accurately predict.     

Morphology development of ZnO produced by sonothermal process

Wurtzite ZnO (hcp) was produced by the 80 °C sonothermal reactions of 1:5, 1:10, and 1:20 molar ratios of Zn(NO₃)₂·6H₂O:NaOH in water, containing 2 g, 5 g, 10 g, and 20 g of polyethylene glycol (PEG) with the molecular weights (MWs) of 6000, 10000, and 20000 for 1 h, 3 h, and 5 h. ZnO phase with different morphologies was detected. When the amount of NaOH, both MW and the amount of PEG, and the experimental time were increased, the products still retain their single phase, but their morphologies were changed from nanoplates in clusters to nanospears with sharp tips gathering together in the shape of flowers, and long nanorods with oval tips in clusters. In the present work, formation mechanism of these products was also discussed.