浅析余热锅炉在硫铁矿制酸生产中的应用

文章论述余热锅炉在硫铁矿制酸生产中的应用,介绍了硫铁矿制酸生产中采用余热锅炉的原因和余热锅炉的主要结构。结合自己的工作经验和本厂的实际情况,分析影响锅炉正常产生的几个要素,提出通过加强日常运行管理来保证锅炉安全、高效运行。     

锅炉燃烧系统的智能化控制

锅炉燃烧系统对热负荷的干扰因素较多,难于实现经济、安全运行,大中型燃煤锅炉对安全指标和经济指标的要求很高。分析了参数控制、352E扩展型可编程调节器功能和热负荷调节原理,在对两台锅炉仪表进行改造时,现场检测仪表采用智能化变送器,控制室监控仪表的检测部分采用计算机数据采集系统,控制部分采用智能化可编程调节器。经五年运行证实了燃烧效率高,实现了经济、安全、平稳运行的效果。     

锅炉主汽温度自动控制的实现

介绍采用模糊控制技术实现锅炉主汽压力的自动控制。锅炉主汽温度自动控制的实现既保障了锅炉的安全运行,在很大程度上也保障了汽机的安全运行,采用模糊策略,模仿有经验的人工操作,已经成为改善调节品质的有力手段和必然趋势。     

锅炉运行及设备维护问题重点探讨

锅炉运行的安全性和稳定性基本决定了锅炉供应可靠性能,因此,为进一步提升锅炉运行过程中安全性,必须全面加强对锅炉运行的维护管理工作,避免锅炉工作过程中出现故障.基于锅炉运行的基本原则和运行方式、运行注意事项分析了影响锅炉正常工作的故障因素,提出了锅炉日常维护优化措施,以供参考.     

40 kt/a烷基化废硫酸回收装置的设计和运行

介绍了烷基化废酸回收装置的生产工艺流程及操作注意事项。重点探讨了裂解炉、余热锅炉等设备的设计选型。高温裂解炉和余热锅炉采用国产技术,余热锅炉运行3个月,未出现堵塞现象。该装置技术可靠,运行稳定,各项工艺指标基本达到或优于设计值。     

硫酸装置锅炉系统防爆管技术总结

介绍了湖北新洋丰农业科技股份有限公司硫磺制酸装置和硫精砂制酸装置锅炉系统的工艺流程和运行情况。针对锅炉和省煤器出现的爆管问题,技术人员采用在脱盐水中加入氨水调节pH值在8.5左右、控制除氧器水温为(103±1)℃、加强精硫品质控制等措施,避免了省煤器、锅炉蒸发管爆管的事故发生,实现了锅炉系统的安全稳定运行。     

美国燃煤工业锅炉技术

介绍了美国工业锅炉的基本情况和主要的燃煤工业锅炉技术,分析了锅炉专用煤的要求及燃煤工业锅炉的污染控制技术。分析发现,美国的燃煤工业锅炉运行年代长,通过不断技术改造使锅炉保持较高的运行效率;美国对不同类型锅炉的煤质有专门规定,以保证锅炉高效率燃烧和低污染排放。美国燃煤锅炉采用各种污染物减排措施,保证了污染物达标排放。     

氯离子的监测在锅炉水处理中的应用

低压锅炉常采用钠离子交换法对给水进行软化处理,根据钠离子交换器再生终点的控制通常仅为硬度指标,提出了再生终点除监测硬度外,还应继续监测氯离子。增加氯离子指标有利于对低压锅炉结垢的原因进行分析,又提出了根据氯离子和碱度的浓缩倍数可判断运行锅炉的结垢状况,实践证明,用两种浓缩倍数对比法判断运行锅炉结垢趋势准确、简便、易行,容易掌握。同时采用监测锅炉水中氯离子含量可间接控制溶解固形物含量,具有操作简单快捷,为锅炉水处理提供简便可行的控制指标。     

余热锅炉减温器的选择与设计

余热锅炉在运行过程中,由于运行参数的波动会导致过热水蒸汽出口温度升高,超出设计误差范围,对锅炉及锅炉下游设备的安全运行带来了危险,由此我们采用蒸汽侧减温的方式来调节余热锅炉过热水蒸汽出口温度,本文主要探讨了蒸汽侧减温器如何选择,并阐述了面式减温器设计过程。     

煤质变化对锅炉运行的影响及优化措施

为了保证燃煤锅炉的燃烧效率,设计人员会结合锅炉结构及运行特性对燃煤性能中的各项参数进行设计,以确保锅炉能够达到设计的燃烧效率。但是很多火电厂为了节省成本,一般会采用掺烧的方式来提高经济效益,这样就会导致燃煤参数偏离设计值。由于掺烧技术不合理,不仅会影响锅炉燃烧热效率,而且还会影响锅炉运行的安全性和稳定性。首先阐述了煤质变化对锅炉运行产生的影响,然后对提高燃煤锅炉运行效率的优化措施进行分析,以提高电厂经济效益。     

Simulation of reverse flow operation for manipulation of catalyst surface coverage in the selective oxidation of ammonia

A mathematical model has been developed for the simulation of the ammonia oxidation in a reverse flow reactor. Computer simulations were carried out with a kinetic scheme, based upon elementary reaction steps. Aim was to explore the potential of a reverse flow reactor for selective oxidation of NH₃ to produce either N₂, NO, or N₂O via a dedicated operation procedure. Therefore, the conversion of NH₃ and the selectivity toward N₂, NO, or N₂O, were compared for a reverse flow operation and a steady state, once-through operation.A new operation concept of reverse flow operation in combination with a periodically lower feed concentration is proposed. The novel reactor concept shows a better performance compared to normal reverse flow operation and to steady state, once-through operation. The results indicate that reverse flow operation can be applied for manipulation of conversion and selectivity. A periodically lower feed concentration may increase the conversion, even up to levels that exceed the steady state value.     

受限空间安全作业管理浅析

受限空间因受作业场所限制,存在的危险因素较多,受限空间安全管理控制措施为:建立许可制,落实责任和措施,做好受限空间作业人员的个体防护,对受限空间作业的安全管理要实行从审批到应急处理全过程的控制。介绍了受限空间的危险特点和事故类型,提出了受限空间作业安全管理的具体措施。     

Design and operation of 800,000 gpd reverse osmosis seawater system

The paper will review the design and operation of the 800,000 gpd reverse osmosis seawater system installed at the Punta Moron Station, of the C.A. de Administration y Fomento Electrico (CADAFE) of Venezuela. The plant will produce potable and boiler feed water for the utility. The specific areas discussed will be as follows: $\text{Pretreatment}$The design and operation of the Permutit Seawater Pretreatment system producing an influent to the membrane system with an SDI less than 3, will be described. $\text{Membrane System}$The B-10 Seawater Membrane system will be reviewed as to design and operation, with particular emphasis on the process and control features necessary to provide low maintenance operation. $\text{Brackish Water System}$ p]The secondary brackish water B-9 system treating the influent from the seawater unit will be reviewed as to design and operation with particular emphasis on its ability to produce low TDS water for the demineralizers providing boiler feed water for the utility.The paper will outline data and the general experience with the operation of a large Reverse Osmosis Seawater plant. In addition, the integration of the brackish and seawater units into a single system will be reviewed.Operating costs will be outlined and the general question of Reverse Osmosis Seawater plant operation will be discuessed. The impact of the successful operation of this first single pass Reverse Osmosis Seawater System on the future of desalting technology will be evaluated.     

Optimization of the operation of a gas terminal

Optimal operation of complex process plants requires the assistance of computer systems for day to day operation. The application of computers in plant operation comprises:

• 1. optimization systems to define the global plant set points such as product purities keeping in mind the physical limits of plant equipment and the boundary conditions of the market for feed and products; and
• 2. advanced process control systems which help the operator to keep the plant as close to these global set points as possible.

This paper deals with the various aspects of an optimization system, which was developed for the gas terminal at Karstø, Norway. It will be shown that, due to the complex process sequence of this plant, the wide range of feedstock quality and the numerous degrees of freedom for operation, the use of the optimization system is essential to ensure plant operation close to its physical limits at minimum operating cost. The optimization system is designed for off-line usage, but can be extended later for on-line use.     

废热锅炉系统汽水循环过程的研究

汽水循环状况对废热锅炉系统的安全运行、稳定操作和延长使用寿命都有重要的意义,通过对甲醇厂废热锅炉系统汽水循环过程进行计算和研究,判断废热锅炉系统循环回路的工作状态,并对现有系统存在的问题提出建议,为稳定工艺生产提供借鉴。     

Application of response surface methodology to optimize the operation process for regeneration of acid and base using bipolar membrane electrodialysis

BACKGROUND: Bipolar membrane electrodialysis (BMED) has been widely used for desalination, concentration, separation, and purification in many fields. The purpose of this study is to optimize the operation conditions using response surface methodology (RSM) for the regeneration of sulfuric acid and ammonia from ammonium sulfate solution by BMED coupled with ammonia in situ stripping. RESULTS: A three‐factor central composite design of RSM was used to analyze the effect of operation conditions (current density, flow rate, initial acid concentration) on average current efficiency (ACE) and establish the optimal operation conditions. The ACE was 76.7 ± 2.2% under optimal operation conditions (current density 23.8 mA cm^?2, flow rate 27.3 L h^?1, initial acid concentration 0.09 mol L^?1). CONCLUSION: A suitable regression model for predicting ACE within the ranges of variables used was developed based on experimental results. The operation conditions were optimized by RSM and the ACE obtained under the optimal operation conditions was in good agreement with the value predicted by the regression model (78%), which proved the validity of the model. Copyright © 2007 Society of Chemical Industry     

炼化装置热网联运存在的问题及建议

针对炼化装置热网联运过程中蒸汽管网末端温度偏低,分析了管线输送过程中的理论热损失和实际热损失,推断要满足蒸汽管线末端最低温度时起点的最低温度。对比燃机排气特性在不同负荷运行下设计与实际运行的差异,余热锅炉初始设计产汽量与实际产汽量的区别以及热网的供需平衡,提出了提高4.2MPa中压蒸汽产量,避免中压蒸汽减压至低压;停输化肥厂中压蒸汽;优化燃机余热锅炉运行;提高余热锅炉运行效率;减少电力工程部至化肥厂蒸汽管线热损失运行改进措施,并要求上级生产运行部门要根据各用户蒸汽需求,及时调整燃机余热锅炉运行,尽量使整个热网系统高效运行。     

乙烯气相聚合过程中氢气振荡操作制备双峰聚乙烯

在单一气相反应器中,采用国产APE-1G(Cp*₂ZrCl₂·2LiCl·THF)型茂金属催化剂,通过强制振荡反应器内的氢气浓度制备双峰聚乙烯。实验考察了氢气浓度、振荡时间分配和振荡周期对聚乙烯分子量分布的影响。实验结果表明,氢气的加入使得催化剂活性降低,产物分子量也减小。通过强制振荡氢气的浓度可以得到双峰分布的聚乙烯,M_w/M_n达到11.2～34.2。研究表明,通过调节氢气振荡操作的实验条件,尤其是调节振荡时间分配,可以很好地控制双峰聚乙烯的分子量分布。     

Carbon dioxide reforming of methane under periodic operation

The carbon dioxide reforming of methane under periodic operation over a commercial Ni/SiO₂·MgO catalyst was investigated at two different temperatures, 923 and 1,023 K. According to this operation, pure methane and carbon dioxide were alternately fed to the catalyst bed where methane cracking and the reverse Boudouard reaction took place, respectively. Therefore, hydrogen and carbon monoxide products appeared separately in different product streams. The performance of this operation was compared to that of the steady state operation with simultaneous feed of both carbon dioxide and methane. At 1,023 K, the methane conversion and hydrogen yield from the periodic operation initially decreased with time on stream and eventually leveled off at values about half of those obtained in the steady state operation with co-feed of both reactants. The decreased catalytic activity was due to the accumulation of carbonaceous deposit and loss of metal active sites. However, a different trend was observed at 923 K. The methane conversion and hydrogen yield were almost constant over the time on stream, although more carbonaceous deposit was progressively accumulated on the catalyst bed during the reaction course. At this temperature, the periodic operation offered the equivalent hydrogen yield to the steady state operation. The observed behavior could be due to the different mechanisms of carbon formation over the catalyst. Finally, it was found that cycle period and cycle split did not influence the reaction performance within the ranges of this study.     

轴径向型氨合成塔的数学模型及工艺优化研究

运用氨合成化学反应本征动力学方程,建立了轴径向型氨合成塔拟均相一维的催化床层内氨浓度和反应温度分布的数学模型。利用正常生产运行的操作数据反算得到了各段催化床层的催化剂活性系数;逐一对单元工艺操作条件进行了优化,模拟计算出系统压力随氨合成塔工艺操作条件变化的情况,从中确定出一组工艺操作条件的优化值;通过实际生产运行,对优化前后氨合成塔工艺操作数据进行了对比,结果实明,生产操作工况良好。