S7-200 PLC在袋装尿素计数系统中的运用

袋装尿素计数系统通常用于对外销售时的产品计量.为提高计数系统的可靠性及操作的便利性,通过采用PLC及触摸屏技术实现计数及控制功能.详细介绍重庆建峰化肥有限公司袋装尿素计数系统的特性、工作原理、系统组成、界面显示及功能.     

袋装水泥袋数计数装置的设计与应用

水泥行业中,袋装水泥袋目前仍占75％以上。许多老企业原设计无袋数计数,给生产管理与内部考核管理带来很多麻烦,容易形成管理漏洞,给企业造成了一定的经济损失。本文根据我公司湿法线技术改造实施情况,介绍一种袋数计数装置。     

高效除油装置在尿素生产系统中的应用

长期以来,CO2压缩机使尿素原料气中严重带油而导致系统中一段分解加热器、二段分解加热器的结垢,影响尿素生产系统蒸汽消耗高,垢层清洗又一直是制约长周期运行的难题。其中以一段分解加热器问题更为突出,而合成塔出料及一分塔出料二次加入空气中的油含量则直接影响一段分解、二段分解加热器的结垢程度。西安超滤净化工程有限公司采用全新的凝聚式除油机理研制的“工艺气超高效除油过滤器”,于1999年8月在山东省章丘市第二化肥厂投用并取得显著成效。     

R100系统在尿素装置中的应用

介绍了美国霍尼威尔公司Ｒ１００系统在贵州兴义化工总厂的实际应用情况，并对Ｒ１００系统的设计、组态和控制算式进行了探讨。     

TPS系统在我公司尿素生产中的应用

我公司老系统尿素生产采用水溶液全循环法,尿素系统DCS改造前,重要工艺参数及调节回路基本上采用＊＊Z皿型仪表,与原设计的气动1型仪表相比有很大的优越性。但是,一些重要工艺参数与设备采用手动控制,制约着尿素系统长周期高负荷安全稳定运行。与集散控制系统相比,运行周期短,维护工作量大,控制手段单一,控制精度差,无法实现量化管理和优化控制。作为公司“12·20’重点技改项目,针对尿素系统的自控状况,在进行调研、论证的基础上,我公司选用了美国霍尼韦尔（Honeywell）公司TPS系统,从1996年起先后完成可行性研究、设备…     

MUVAC系统在尿素装置上的应用

本文介绍了 PROVOX 集散系统和 MUVAC 系统的情况,特别对大化肥厂尿素装置的技术改造有参考意义。     

ND钢在余热锅炉上的应用

采用２０Ｇ 省煤器的余热锅炉,由于腐蚀严重,生产周期特别短,因此,在对腐蚀原因进行了分析,采用耐低温露点腐蚀ＮＤ 钢制造的省煤器,提高了省煤器的使用周期,产生了巨大的经济效益。     

水抽真空在尿素蒸发系统的应用

山东明水化工有限公司原2^#尿素蒸发系统一段和二段使用的是1．3MPa（绝）蒸汽,通过蒸发喷射器抽真空。由于该系统蒸汽消耗高,蒸汽压力波动大,导致一、二段真窄度波动大,尿素成品质量得不到保证,尤其在夏季,不得不依靠减量来维持系统生产。当系统生产负荷过重或一、二段蒸发冷凝器出现部分堵塞时,冷却器冷凝效果极差,不凝气中的氨含量升高,在造粒时随造粒塔放空排人大气,不仅造成吨尿素消耗高,而且污染空气,不利于环保。     

双作业机器人袋装水泥智能装车系统设计*

针对目前大部分水泥厂包装车间发运装车机的弊端,研究并设计开发了一种双作业机器人袋装水泥智能装车系统。介绍了系统组成与工作流程,详细分析了其控制系统原理,总结了系统的特点。整套设备结构合理、技术先进、运行稳定、操作简便,对水泥厂各种类型的水泥运输车辆有良好的适应性。     

尿素工艺DCS控制系统增容设想

在现有DCS控制系统的基础上,进行了初步增容改造的设想,对CO2压缩机和合成系统增加了部分新的控制手段和方法。     

船舶管路系统投运前的中性化学清洗

阐述了船舶管路系统投入运行前进行化学清洗的必要性。根据设备特点,设计了中性化学清洗的方案和清洗工艺,选择了专用的中性除油除锈剂。清洗结束后,经过检测达到了标准规定的指标。     

Recovery of nitrogen by spring barley from ammonium nitrate,urea and sulphur-coated urea as affected by time and method of application

The objective of this study was to increase the efficiency of fall-applied N either by placement in bands or by using a slow-release fertilizer. Four field experiments were conducted in north-central Alberta to determine the influence of N source, time of application and method of placement on the recovery of fall-applied N as soil mineral N in May, and on yield and recovery of N in grain of spring-sown barley. The recovery in soil of mineral N by May from the fall-applied fertilizers varied among treatments. More specifically, the recovery was lowest with topdressed application, highest with banding, and tended to be less with incorporation application as compared to banding. Recovery of mineral N was least for sulphur-coated urea (SCU) compared with A.N. and urea, regardless of method of application. The loss of fall-applied N was substantial, but leaching did not go beyond 60 cm deep.Yield and recovery of N in barley grain were much greater with spring application than with fall application at the 4 sites for ammonium nitrate (A.N.) and at 3 sites for urea. The SCU treatments were inferior. The A.N. and urea had greatest yield and N recovery with banding, followed by incorporation and then with topdressing for both fall- and spring-applied N. Method of application had little effect on yield and N uptake with SCU. In all, the greatest yield or crop N uptake was obtained with spring banding of A.N. or urea, while SCU did not function well as a fall- or spring-applied N fertilizer.(Contribution No. 680)     

包膜控释尿素在湖北中稻上合理施用量的研究

在湖北省中稻上开展了控释尿素不同施用量的田间试验。研究结果表明,施用控释尿素不仅可以提高中稻产量,而且可以提高氮肥的农学效率及表观利用率,控释尿素70%的用量与普通尿素100%的用量效果相当,并随着控释尿素施用年限的增加,控释尿素施用效果越显著,控释尿素至少可以减少氮肥用量30%。     

N2O and NO emissions from a field of Chinese cabbage as influenced by band application of urea or controlled-release urea fertilizers

A field experiment was conducted in an Andosol in Tsukuba, Japan to study the effect of banded fertilizer applications or reduced rate of fertilizer N (20% less) on emissions of nitrous oxide (N₂O) and nitric oxide (NO), and also crop yields of Chinese cabbage during the growing season in 2000. Six treatments were applied by randomized design with three replications, which were; no N fertilizer (CK); broadcast application of urea (BC); band application of urea (B); band application of urea at a rate 20% lower than B (BL); band application of controlled-release urea (CB) and band application of controlled-release urea at a rate 20% lower than CB (CBL). The results showed that reduced application rates, applied in bands, of both urea (BL) and controlled-release urea fertilizer (CBL) produced yields that were not significantly lower than yields from the full rate of broadcast urea (BC). The emissions of N₂O and NO from the reduced fertilizer treatments (BL, CBL) were lower than that of normal fertilizer rates (B, CB). N₂O and NO emissions from controlled-release urea applied in band mode (CB, CBL) were less than those from urea applied in band mode (B, BL). The total emissions of N₂O and NO indicated that applying fertilizers in band mode mitigated NO emission from soils, but N₂O emissions from banded urea (B) were no lower than from broadcast urea (BC).     

RS-3系统在斯纳姆氨气提尿素生产装置上的应用

介绍RS－3集散系统与PLC系统在SMAM氨气提尿素生产装置上的应用情况,着重阐述了自控装置的硬件构成与实施方案。     

秸秆黄腐酸包膜尿素在水稻上的应用效果

在石灰性土壤上进行田间小区试验，结果表明，秸秆黄腐酸包膜尿素能满足水稻生长最大效率期对营养的要求，有利于有效穗的分化，提高结实率。等氮量试验平均增产9．6％，等重量试验平均增产7．4％。     

小管板在尿素二段蒸发加热器上的应用

针对尿素二段蒸发加热器的损坏原因,重点介绍采用小管板延长二蒸加热器的寿命。     

国产MACS分布式系统在氯乙烯精馏中的应用

讨论了DCS系统在氯乙烯精馏中设计和应用情况,江苏金浦北方氯碱化工有限公司采用MACS分布式系统,融合现场总线技术,使氯乙烯精馏系统实现了全方位控制。