赤天化氨汽提尿素装置运行与改造

简要阐述了赤天化ＮＨ３汽提尿素装置的运行情况及在运行过程中工程技术人员对该装置实施的部分技改技措,以及ＮＨ３汽提装置仍然存在的缺陷。     

氨汽提尿素装置高压设备腐蚀状况分析

对运行了10a的氨汽提装置4台高压设备进行全面检测,根据大修期间腐蚀检测情况,结合设备自身的特点,论述斯那姆氨汽提尿素装置高压设备的腐蚀问题。     

NH3汽提尿素装置解吸操作优化与低压系统改造

介绍赤天化ＮＨ３汽提尿素装置解吸系统与低压系统存在的问题及处理措施。     

尿素低压放空阀全关探讨

对高压系统在不同的ＮＨ３／ＣＯ２、Ｈ２Ｏ／ＣＯ２下进行了试验性操作，在斯那姆工艺允许的范围内，低ＮＨ３／ＣＯ２操作优于高ＮＨ３／ＣＯ２；考虑到设备能力问题，高、中、低压的分解温度都略有提高，低压系统外加冷却后的蒸汽冷凝液，适当提高解吸到低压的汽相温度，低压放空阀即可全部关闭。     

由氨汽提尿素工艺谈尿素生产防爆措施

根据氨汽提法的一些工艺条件，核算尾气组成，并用相图分析气体的安全性。根据相图提出尿素生产防爆措施：严格控制ＣＯ２、ＮＨ３纯度，氧加入量，改变加氧方式，某些设备、部位专设接地装置等措施，防止爆炸。     

CO2汽提法和NH3汽提法尿素装置工艺比较

通过从设计理论到生产实际运行效果，对ＣＯ２汽提法和ＮＨ３汽提法两种大型尿素生产工艺的技术经济性及可靠性作一比较，以供同行在改扩建化肥厂时作选型参考     

CO_2汽提法尿素装置高压设备入塔检测前的工艺处理

CO_2汽提法尿素装置4台高压设备——CO_2汽提塔、高压甲铵冷凝器、尿素合成塔、高压甲铵洗涤器布置在高框架内,管道与设备间和管道与管道间全部采用焊接连接,设备间无法通过断开管道法兰的形式拆开,高压系统严苛的工况与设备结构的特殊性决定了高压设备定期检测工作的重要性。阐述高压设备定期检测的必要性,对高压设备入塔检测前的工艺安全处理要求、设备保护方面的注意事项、工艺处理步骤与具体操作等进行详细介绍,以利保护设备与保证安全入塔检测。     

斯纳姆氨汽提尿素装置高压圈升温的优化控制

主要对斯纳姆氨汽提大颗粒尿素设备装置进行分析,并对尿素装置高压圈升温问题进行分析,针对高压圈升温现象进行优化与控制。并通过高压圈延伸到装置中其他高压设备,研究高压设备的腐蚀问题,针对这种现象找出解决的方案,希望可以有效促使斯纳姆氨汽提大颗粒尿素的高效生产。     

螺栓拉伸器预紧压力计算法

螺栓拉伸器预紧压力计算法常祖山（中原化肥厂，河南濮阳，４５７００４）收稿日期：１９９６－０９－１２。中原化肥厂５２万ｔ／ａ尿素装置４台高压设备（尿素合成塔，ＮＨ３汽提塔，甲铵冷凝器，甲铵分离器）人孔螺栓均为Ｍ６４，这４台人孔螺栓的预紧、热紧与拆卸采用...     

尿素装置的热量回收

尿素装置的热量回收１尿素制造法在过去３０年里，尿素生产技术的发展主要在于降低能耗和开发防腐蚀材料。从尿素合成的反应式来看它是一个放热过程：２ＮＨ３＋ＣＯ３＝ＮＨ４ＣＯＯＮＨ２－１５９ｋＪ／ｍｏｌ－→ＮＨ２ＣＯＮＨ２＋Ｈ２Ｏ—１３８ｋＪ／ｍｏｌ但在工业...     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

氯苄双羰基化反应动力学模型

氯苄双羰基化反应生成苯丙酮酸钙的过程是一个多相催化反应过程。通过对反应机理的研究,推导出实际操作的等温等压条件下反应动力学方程,并用实验数据加以验证。     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。