合成氨透平压缩机组调速控制系统改造

合成氨装置压缩机组原机械调速系统存在调速精度不高、容易出现故障、存在安全隐患和操作不方便等问题,特别是透平压缩机组机械调速系统不能与整个合成氨装置先进的计算机DCS集散控制系统联机进行闭环控制。应用康吉森TS 3000透平压缩机组综合控制系统(ITCC)对合成氨压缩机组原机械调速系统和相应的控制油路进行改造,实现全电子调速及压缩机组与整个合成氨装置DCS的自动化控制和安全联锁,确保装置安全生产,为企业带来经济效益和社会效益。     

L-谷氨酰胺的生理特性及其应用

L-谷氨酰胺作为人体中含量最多的一种氨基酸,在调节人体蛋白质的合成、抑制蛋白质的降解、刺激细胞生长、激活免疫功能、提高生长激素水平方面起着重要作用。本文阐述了L-谷氨酰胺的生理特性及其应用。     

Cost-Effective Nutrient Reductions to the Baltic Sea

Due to eutrophication caused by heavy loads of nitrogen and phosphorus, the biological conditions of the Baltic Sea have been disturbed: large sea bottom areas without any biological life, low stocks of cods, and toxic blue green algaes. It is recognized that the nitrogen and phosphorus loads to the Baltic Sea must be reduced by 50% in order to restore the sea. The main purpose of this paper is to calculate cost effective nitrogen and phosphorus reductions to the Baltic Sea from the nine countries surrounding the Baltic Sea. The results show a significant difference in minimum costs of decreasing nitrogen and phosphorus loads to the Sea: approximately 12 000 millions of SEK per year and 3 000 millions of SEK respectively for reductions by 50%. It is also shown that a change from a policy of cost-effective nutrient reductions to a policy where each country reduces the nutrient loads by 50% increase total costs for both nitrogen and phosphorus reductions by about 300%. The results are, however, sensitive to several of the underlying assumptions and should therefore be interpreted with much caution.     

氮气环境下催化剂安全卸装技术要求

文章对氮气环境下催化剂卸装提出了切实可行的安全技术要求,指出安全技术条件的保证是氮气环境下催化剂卸装的关键,并指出今后我国石油化工、化肥企业催化剂卸装的方向。     

Is Site-Specific Yield Response Consistent over Time? Does It Pay?

This study examines the profitability and stability of site-specific (SS) nitrogen fertilizer recommendations using an empirical model of SS yield response to controlled inputs, stable site characteristics, and time-varying weather factors. Using a three-year panel of on-farm corn yield experiments and new, continuous variables to describe site characteristics, both spatial and ordinary least squares regression models show clear evidence of SS corn yield response to nitrogen fertilizer. Yield response is predictable only on irrigated fields. Even there, bootstrapped confidence intervals for profitability gains on selected fields indicate that SS nitrogen application would rarely cover its costs.     

Potential of feed additives to improve the environmental impact of European livestock farming: a multi-issue analysis

Today, less than 3% of the 250,000 plant varieties available to agriculture are in use. Sources of (agricultural) biodiversity are under threat and disappearing in many regions. Increasing industrialisation of agriculture and top-down agricultural research have contributed to this dependence on a relatively few plant varieties. This article argues that new approaches to agricultural development research are needed to conserve agricultural diversity, improve crops, and produce food of quality for all. Such an approach should enable small farmers on marginal lands to participate as equal partners alongside agricultural scientists, fairly sharing their know-how, expertise and seeds. Three case studies illustrate how farmers and plant breeders are working together in a diversity of agro-ecological, socio-economic and political contexts to put these new approaches into practice. New forms of collaboration are producing an increase in diversity and a number of promising improved varieties in terms of yields, agronomic traits and taste. These varieties are showing better adaptation to the local environmental conditions without requiring extra external inputs. Long-term success requires that these efforts be backed up by supportive policies, by actions to ensure that policies are implemented, and where necessary by related legislation.     

乙酸钠碳源和铁盐除磷剂对活性污泥系统的影响

为进一步提高污水处理厂工艺运行调控技术水平,通过3套SBR小试处理系统,考察了乙酸钠碳源和铁盐除磷剂2种药剂对污水脱氮除磷效果和活性污泥性质的影响。结果表明：投加250 mg/L的乙酸钠碳源和70 mg/L的铁盐除磷剂均可显著提高除磷效果,均可实现出水总磷达到一级A排放标准,其中,投加铁盐除磷剂会削弱生物除磷效果,且随着铁盐除磷剂投加时间的延长,生物除磷效果下降程度增加,而投加乙酸钠碳源会明显增强生物除磷效果,并减轻除磷剂对生物除磷的抑制作用;投加乙酸钠碳源可明显提高反硝化效果,投加铁盐除磷剂反硝化效果略有提高,但不明显,2种药剂对硝化反应均无明显影响;投加乙酸钠碳源可使MLVSS/MLSS,SVI及SOUR值增加,而投加铁盐除磷剂使MLVSS/MLSS和SVI值降低,SOUR值增加。通过考察进一步掌握了2种药剂对污水处理厂活性污泥系统的影响,可为污水处理厂工艺调控提供科学实用的技术参考。     

利用氨吸收电厂烟道气中的CO2及对大气减排CO2的分析

对以氨吸收电厂烟道气中CO2生产碳酸氢铵的技术可行性进行了分析,并从氨的来源、各种合成氨工艺的能源消耗、附带CO2排放情况和碳酸氢铵在土壤中被植物吸收情况等方面进行了综合分析。结果表明,由于以天然气为原料合成氨生产过程中附带CO2排放相对较少,用于吸收电厂烟道气中CO2生产碳酸氢铵肥料,在碳酸氢铵能够有效被植物吸收的前提下能够达到减排CO2的综合效果。     

On levies to reduce the nitrogen surplus: The case of Dutch pig farms

Pig farms in the Netherlands pay a zero or low price for using the environment. As a consequence, the environment is overused. The Dutch government wants to reduce the emissions of nitrogen and phosphorus. Possible instruments are regulation and levies. In this study a levy on feed and a levy on the nitrogen surplus are investigated, by incorporating a bad output in the production model. The model is estimated using panel data of Dutch pig farms over the period 1975–1989. Levies on nitrogen turn out to be more cost-effective than levies on feed.     

短程硝化反硝化生物脱氮工艺及影响因子

介绍了传统生物脱氮工艺和短程硝化一反硝化工艺原理，提出了短程硝化反硝化的关键是如何控制硝化过程中NO2^--N的积累。分析了影响NO2^--N积累的主要因素为温度、游离氨、pH值、溶解氧、有害物质和泥龄，提出了实现短程反硝化的控制条件。