尿素换代产品的开发与应用

当前尿素供求关系失衡,越来越多的尿素生产企业向传统产品创新及差异化方向发展,使尿素行业产品结构发生大的调整.本文介绍了国内近期多肽尿素、双酶尿素、硫包衣尿素、腐植酸尿素4种尿素新型产品的研制开发及应用概况.     

尿素新型产品的开发与应用

面对当前尿素行业供求关系失衡,越来越多的尿素生产企业在传统产品的创新及差异化方向发展,新型尿素品种将在市场中占有一席之地,也使尿素行业产品结构有很大的调整,更加适应农业种植结构和质量效益型农产品生产的新形势发展需要。介绍了国内近期多肽尿素、双酶尿素、硫包衣尿素和腐殖酸尿素4种尿素新型产品的开发及应用概况。     

大颗粒尿素装置产品多元化的研究与应用

依托氨汽提大颗粒尿素生产装置进行产品多元化研究,采取小规模技术改造,成功生产多肽尿素、小颗粒尿素、车用尿素,为大颗粒尿素装置的多元化生产提供经验。     

50 kt/a车用尿素装置运行中存在的问题及对策措施

尿素生产企业建设车用尿素生产装置,有助于提高尿素产品的附加值,增强企业抗风险的能力。概述了车用尿素生产工艺流程及产品质量指标,分析了车用尿素装置在实际运行过程中出现配制槽尿素浓度变化大、配制时间长、成品槽内产品被污染、产品中醛类物质超标等问题的原因。采取相应的措施后,实现了车用尿素装置的稳定运行,产品质量达到了国家标准的要求。     

改产大颗粒尿素技术方案比较与选择

当今尿素市场竞争剧烈，与普通粒径的尿素相比，大颗粒尿素具有良好特性，因此，改产大颗粒尿素，开拓产品市场、提高工厂经济效益具有重大意义。现从市场现状、改产规模、产品规模以及改产大颗凿尿素采用的工艺技术，消耗指标等进行分析比较，仅供同行参考。     

提高尿素产品外观质量的技改措施

塔里木油田塔西南石化厂为解决尿素产品板结的问题,采用了在尿素中加入甲醛的技改方案。介绍了甲醛及其水溶液的理化性质;简述了在尿素中添加甲醛溶液的工艺原理和工艺流程。监测分析结果表明：控制尿素中甲醛含量在0.18%～0.3%之间时,尿素中总氮、水分、缩二脲含量无明显变化,而尿素颗粒强度明显提高,由未添加甲醛前的7.3 N提高到8.6 N。此外,尿素产品的粉尘量明显减少,尿素成品粒度由98%上升到98.5%。     

多肽尿素发展概况与应用前景

当前尿素行业供求关系失衡,市场竞争激烈,越来越多的尿素生产企业开始关注传统产品的创新及差异化,新型尿素品种逐渐增多,在市场中也占有了一席之地,使得尿素行业产品结构有了很大地调整,产品更加适应农业种植结构和质量效益型农产品生产新形势发展的需要。国内近期开发的多肽尿素就是其中一种新型尿素产品,介绍了近年来多肽尿素的研制开发及应用概况,并对国内多肽尿素的发展提出了一些建议。     

增值尿素开发和尿素深加工产品探索

介绍普通尿素的产能、市场现状及用途。分析增值尿素的开发和下游产品深加工的探索,重点介绍多肽尿素、三聚氰胺、车用尿素的生产工艺流程、市场前景等。     

尿素深加工产品的应用和开发前景

本文概述了尿素深加工产品的门类、用途及其国内开发动向。尿素既是一种含氮很高的固体肥料,又是一种重要的化工原料。近年来,国内外不断开发尿素的深加工产品。在尿素参与生产的多数产品中,具有耗用原料少,见效快等特点,     

小尿素厂生产大颗粒尿素产品技术探讨

本文论述了小尿素厂生产大颗粒尿素产品的必要性,并根据世界上大颗粒尿素生产技术情况探讨了我国小尿素厂生产大颗粒尿素的技术路线。     

缓释和控释尿素的研究与开发综述

分析了尿素利用率低对环境的影响和尿素在土壤中的释放过程，阐述了各种缓释和控释尿素的产品设计，缓释机理和制备方法以及国内外对缓释和控释尿素尤其是包膜尿素的研发进展，对提高尿素利用率，研究高效控释包膜尿素进行了展望。     

Ammonia volatilization from a flooded rice field fertilized with amended urea materials

The extent of ammonia volatilization from prilled urea, urea supergranule and urea amended with neem seed cake, shell-lac and dicyandiamide was studied in a field experiment on flooded rice. The ammonia loss was measured by the closed acid trap method. The collected ammonia was highest from unamended prilled urea, accounting for 19 to 20 per cent of the applied N in 1983 and 20 to 24 per cent of the applied N in 1984. Coating of urea prills was either coaltar soaked neem seed cake or shell-lac was more effective than coating with dicyandiamide in reducing ammonia loss. Deep placement of urea as a supergranule was the most effective method of reducing ammonia volatilization. A diurnal variation in the pH and temperature of floodwater was observed. The quantity of ammonia collected in the acid trap was closely related to ammoniacal-N concentration and pH of the floodwater.     

控释尿素和控释BB肥对夏玉米的增产效果研究

采用控释尿素和普通尿素两种氮素肥料及含控释尿素的BB肥进行夏玉米肥效试验研究。试验结果表明：100％控释尿素处理产量最高,为8714kg／hm^2。和8838kg/hm^2,与同等氮素用量的普通尿素相比,分别增产658kg／hm^2和667kg／hm^2,提高8．2％和8．2％,增产效果显著;控释尿素用量在70％～100％时,产量随氮肥用量的增加而增加,普通尿素也呈同样趋势;70％控释尿素处理与100％普通尿素处理相比,产量差异不大,没有达到显著性差异,说明施用控释尿素可以比普通尿素用量减少约1／3的纯氮用量,夏玉米作物产量并不下降。     

Solubility of metallic-salt in acid nutrients in acid fertilizer solutions of urea phosphate,urea sulfate and urea nitrate

Solubilities of individual metallic-salt micronutrients were determined at 0°C in saturated acid fertilizer solutions of urea phosphate, urea sulfate, and urea nitrate. By using the acid pH mechanism, less expensive metallic salts can be used with drip irrigation applications to supply specific micronutrient needs to crops.Solubility of the sulfates of Cu, Fe, Mn, and Zn varied with each acid solution. Solubility of the above sources in the urea sulfate solutions also varied with the amount of sulfate in solution. The solubility of molybdenum decreased with the acidic conditions of the urea nitrate acid solution but appeared to increase for the urea phosphate and urea sulfate acid solutions. Boron was only slightly soluble in all the acid solutions.     

A comparative study of urea hydrolysis rate and ammonia volatilization from urea and urea calcium nitrate

A comparing of urea hydrolysis and NH₃ volatilization from urea supergranules and urea calcium nitrate (UCN, a new fertilizer produced by Norsk Hydro A/S, Norway) was made on two different flooded soil types, a high-CEC clay loam (Ås) and an intermediate-CEC clay loam (Kinn).Nitrogen loss by ammonia volatilization was reduced from 17% by surface application of urea supergranules (USG) on flooded Ås soil to 3% and 6% by UCN briquettes at either the same urea or nitrogen concentration as USG. A significant reduction was even found with the surface application of prilled UCN, 12% and 18% N-loss for prilled UCN and urea, respectively. The floodwater pH and NH ₄ ⁺ content was lower with UCN than urea, which reduced the potential for ammonia volatilization.NH₃-loss (5%) was significantly less when USG was surface applied on Kinn soil, while NH₃-loss from UCN briquettes was independent of soil type. The reduction in NH₃-loss from USG on Kinn soil was due to a decrease in the pH and NH ₄ ⁺ content of the floodwater caused by a reduced rate of urea hydrolysis.The rate of urea hydrolysis was lower with UCN than USG in both soils, but the difference between UCN and USG was greater in the Ås soil than in the Kinn soil. Three days after deep placement (10 cm), 18% of UCN urea and 52% of USG urea were hydrolyzed in Ås soil, while only 12% UCN and 17% USG were hydrolyzed in the Kinn soil.The surface application of USG on flooded soil reduced the rate of urea hydrolysis as compared to deep placement. 30% and 17% of USG urea was hydrolyzed after four days on Ås and Kinn soil, respectively. During the first few days the rate of hydrolysis of UCN was more affected by the soil type than the application method. Four days after surface application 32% and 13% UCN urea was hydrolyzed on Ås and Kinn soil, respectively. The rate of urea hydrolysis exhibited a zero-order reaction when USG and UCN-briquettes were point placed in flooded soils.     

金正大包膜尿素与普通尿素不同掺混比例对玉米肥效试验的研究初报

从金正大包膜尿素与普通尿素不同掺混比例对玉米肥效的试验结果看:70%包膜尿素 30%普通尿素掺混比例处理产量最高,667m2为586 kg,比包膜尿素处理增产5%,比普通尿素处理增产22%;从作物经济性状产量构成因素看,主要在穗粒数表现差异较大。     

控释尿素在夏玉米上的施用效果及氮素利用率研究

通过田间试验方法,对比评价控释尿素在夏玉米上的施用效果和方法。根据施用控释尿素对玉米籽粒产量、氮素吸收和利用率的影响,探讨控释尿素在夏玉米上的施用效果。试验结果表明：与普通尿素相比,施用控释尿素后,玉米产量及氮素利用率均明显提高。     

工业尿素合成理论（一）

以多学科综合分析法，叙述传统工业尿素合成理论和现代工业尿素合成理论的建立过程；从理论上分析了传统工业尿素合成理论的缺陷和弊病。以超临界共沸相图取代了原来的相平衡，并汲取了20世纪80年代后国际尿素技术中有关工业合成的新理念，从而诠释了工业生产上尿素合成塔中的合成反应化工过程，改进了传统尿素合成理论，建立了新型的现代工业尿素合成理论。     

尿素造粒塔粉尘产生的原因及排放控制措施

论述尿素造粒塔中尿素粉尘形成的主要原因及减少粉尘弥散的可能途径。