低(等)压合成氨的最佳H2/N2与催化活性的关系

采用高压催化剂性能评价实验装置，在压力分别为7.0,10.0和15.0MPa，温度分别为350,400和450℃条件下，在H2／N2为1.6-3.0范围内研究了H2／N2对A301，ZA－5和A110－2型催化剂的活性和合成塔出口氨浓度的影响。在压力和空速一定的条件下，最佳H2／N2随反应温度而异。在350，400和450℃下，最佳H2／N2分别为1.8-2.2,2.2-2.5和2.5-3.0。由此可见，合成氨反应的速率达到最大值时的最佳H2／N2值与反应的进程有关。为此提出了催化剂效率K（Catalysis efficiency)的概念来表征在催化剂作用下反应器出口氨浓度趋近平衡的程度，即K＝CNH3／C^*NH3。根据实验结果，得到了最佳H2／N2与催化剂效率的定量关系：（H2／N2）m=1.5(1 CNH3/C^*NH3)=1.5(1 K)。由此可以根据催化剂在不同反应条件下的催化剂效率来确定最佳H2／N2。凡是会降低催化剂效率的因素，都会使最佳H2／N2降低。各种影响因素对最佳H2／N2的影响中，反应温度的影响最大，其次是空速和催化剂的活性，而压力和惰性气体含量的影响相对较小。在低温（低压）下合成氨，宜采用较低的H2／N2。     

新型氨合成催化剂的选用和还原

介绍了氨合成催化剂的创新和发展、A301型和ZA-5型Fe1-xO基氨合成催化剂的性能特点及新型低温低压高活性氨合成催化剂的选择原则。以A301型催化剂为例,详细讨论了新型氨合成催化剂的升温还原方法。     

The role ofAzolla in curbing ammonia volatilization from flooded rice systems

By the year 2020, an additional 300 million tons of rice are needed annually to meet the demands of a growing population. If our natural resource base is to be preserved, intensification strategies should rely on integrated nutrient management, making full use of biological nitrogen fixation. TheAzolla-Anabaena complex is amongst the most effective systems of fixing nitrogen. In this paper we present evidence from greenhouse studies on the potential ofAzolla to curb the volatilization of NH₃ following the application of urea to a mixedAzolla-rice culture, providing a new incentive for developing ways of integratingAzolla in intensive rice cultivation systems.The results of a series of short term greenhouse experiments show that a full cover ofAzolla can significantly reduce losses of applied urea-N from 45 and 50% to 20 and 13% for the 30 and 60 kg N ha^–1 treatments, respectively. About one-quarter of the applied N was tied up in theAzolla biomass. The applied N inhibitedAzolla growth as well as the amount of N fixed. Inoculation with smaller quantities ofAzolla allowing for more vigorousAzolla multiplication was equally effective in reducing NH₃ volatilization and doubled the amount of¹⁵N tied-up byAzolla. The reduction in NH₃ volatilization is largely related to the depression byAzolla of the floodwater pH, which in its absence may reach values between 9 and 10 as a result of algal activity.Early rice growth responded positively to urea as well as the large quantities of appliedAzolla and increased the yield potential of the crop. Smaller quantities ofAzolla alone were not effective in this regard. The conservation of fertilizer N byAzolla, particularly when it fully covered the water, was reflected in a synergistic effect on rice dry matter production, amounting to 9% at the 30 kg N rate and 16% at the 60 kg N rate. In all likelihood this interaction is attributable to the higher efficiency of the applied N. The benefits ofAzolla in conserving basal urea-N even in small quantities (200-500 kg fresh material ha^–1), outweighed competition for the applied N and may be as important as its BNF. The most promising integratedAzolla/rice management systems emerging from our studies should be given further attention under field conditions.     

湿式氨法脱硫工艺及应用

随着二氧化硫对环境的污染越来越严重,国家环保总局对烟气二氧化硫排放控制严格,烟气脱硫显得日益重要。简单介绍了湿式氨法烟气脱硫技术的工艺流程及实际应用情况。湿式氨法脱硫工艺具有原料易得、脱硫塔不易结垢、不产生废水、副产品硫酸铵可作为农用肥料,减少了对环境的二次污染等特点,是较适合我国国情的烟气脱硫技术。     

15万t/a双甲氨合成联合装置设计

从工艺路线的比较、压力等级的选择、主要设备的选型等方面阐述了双甲氨合成联合装置的设计特点。结合生产运行实践,分析了双甲氨合成工艺路线的运行参数,与采用不同工艺的生产消耗和产品成本进行了对比。结果表明,该工艺吨氨节约成本80元,精醇成本为1112.6元/t,经济效益显著且生产运行稳定。     

高压氨泵干气密封泄漏的故障分析与处理对策

分析多级离心式高压氨泵干气密封损坏泄漏的原因,是机封紧定套失效使机封内侧动环传动轴套和定位轴套外移,动、静环比压加大,磨损加剧,密封面损伤而泄漏.采取在车床上单边进刀量为0.25 mm的整形光刀措施,可继续使用.     

探讨回收污水中有用的物质

重油催化裂化等的污水含汽油、硫和氨，将汽油、硫和氨回收是哈尔滨石化分公司具有发展前景的项目。     

氮化硅结合碳化硅管状制品的研制

简介了氮化硅结合碳化硅管状制品研制的必要性 ,确定了原材料及粒度配比 ,选择了合适的成型方法及添加剂 ,介绍了氮化烧成机理。研制出的制品其质量和使用性能接近同类进口产品 ,具有良好的市场前景和广泛的推广应用价值。     

Increasing urea-N efficiency for transplanted lowland rice by pneumatic injection: Yield and economics at the farm level

To increase the fertilizer-N efficiency in lowland rice (Oryza sativa L.) cultivation, new management practices are needed. Main cause of the present low efficiency is the low N recovery by plants, as a considerable part of the N applied is lost; deep placement techniques improve the recovery. A pneumatic injector, with which urea prills can be point-placed at a depth of 5–10 cm in paddy soils, was tested in 38 on-farm trials in 1989/90, mostly during the wet season. The experiments, located in Africa and Asia, focussed on differences in grain yield between conventional methods of broadcasting urea and injection by the pneumatic injector, at recommended N-rates. The study shows that the pneumatic injector is effective as a tool to improve the N fertilizer efficiency. The average yield increases per region, resulting from the use of the injector, ranged from about 250 to 1300 kg grain ha^–1. The value of the yield increase would allow most farmers to recover the costs of the injector within one season, even if labour was hired to carry out the injections. The average labour requirement of the injector was 40 hours ha^–1. In Indonesia, injection of prilled urea gave yields similar to those obtained with urea briquettes.     

垃圾渗滤液中氨氮的处理技术

阐述了氨氮对垃圾渗滤液处理效果的影响，介绍了垃圾渗滤液中氨氮的脱除方法、技术特点及工作原理，结合国内外的工程实例，对各种处理技术进行了分析比较。