广西田东电厂氨-硫酸铵法与石灰石-石膏法烟气脱硫技术比较

文章介绍了2种典型的火力发电厂烟气脱硫(FGD)技术(石灰石-石膏法和氨-硫酸铵法)的脱硫工艺和脱硫过程,分析了其相关机理及技术特性,并以广西田东电厂1~#和2~#机组为例对比了2种脱硫工艺的经济性,同时对二者的优缺点做了充分讨论。从烟气脱硫系统的投资、副产品价值和资源综合利用等方面进行综合技术经济分析可知,采用氨-硫酸铵法进行烟气脱硫具有一定的优势。     

石灰石-石膏湿法烟气脱硫氧化空气管窥

目前,火电厂烟气脱硫使用最广的工艺是:石灰石-石膏湿法烟气脱硫。而石灰石-石膏湿法烟气脱硫工艺的主要技术是喷淋塔。经过多年的研究,石灰石-石膏湿法烟气脱硫工艺已经初步形成。强制氧化、自然氧化、抑制氧化是石灰石-石膏湿法烟气脱硫氧化工艺的三种方法。其中,强制氧化是目前各国最常采用的工艺,由于受吸收塔浆液密度、深度、温度、PH值、氧化率及空气压力、氧化空气设计形式等各方面的影响,使得运行要求和总效果也不尽相同。     

石灰石-石膏湿法脱硫工艺技术探讨与实践

干法脱硫工艺脱硫效率较低,设备庞大、投资大、占地面积大,操作技术要求高。为了规避干法脱硫所产生的负面效果,业界通过技术研究,提出了一种石灰石/石灰原石膏湿法烟气脱硫工艺。该工艺脱硫效率高、技术成熟、吸收剂资源丰富,价格便宜,很好的规避了干法脱硫工艺的缺陷,逐渐成为我国烟气脱硫的主要形式。本文将讨论石灰石/石灰原石膏湿法烟气脱硫工艺,并就该工艺应用于国电谏壁发电厂#7、#8炉脱硫实践情况进行总结。     

浅谈石灰石-石膏湿法脱硫技术对脱硝效率的影响

本文以2×330MW和2×660MW大型燃煤火电厂的4台锅炉为研究对象,采用烟气测试仪对烟气中的大气污染物进行测试分析,探讨石灰石-石膏湿法脱硫技术对低氮燃烧的脱硝效率的影响。试验结果表明:石灰石-石膏湿法脱硫技术对烟气中氮氧化物(主要成分为一氧化氮和二氧化氮)仅吸收1.21%-6.63%,说明石灰石-石膏湿法脱硫技术对脱硝效率影响不大。     

发电厂对烟气二氧化硫控制技术探讨

针对发电厂对烟气二氧化硫控制技术探讨问题,对目前燃煤过程的主要脱硫工艺进行了介绍,探讨了石灰石/石膏湿法的脱硫工艺、烟气循环流化床脱硫工艺、新型一体化干法脱硫工艺和氨法脱硫工艺,通过对发电厂现行两种脱硫工艺效果的探讨,循环干法烟气脱硫技术和CFB脱硫工艺,对两种不同脱硫工艺系统进行了比较。为发电厂脱硫技术选择和创新提供了依据。     

石灰石-石膏法脱硫浆液起泡研究

在石灰石-石膏法脱硫中,吸收塔浆液溢流是较为常见的现象,它会对脱硫系统的正常运行造成较大危害,如果不采取适当的预防和处理措施,甚至会导致诸如增压风机叶片损坏等重大事故。通过分析石灰石-石膏工艺中吸收塔浆液产生溢流现象的各种原因,提出防止和解决吸收塔浆液溢流的方法,以保证脱硫系统的正常运行。     

日照钢铁2×180m~2烧结烟气氨法脱硫存在问题及解决措施

文章以日钢2×180m2烧结烟气氨法脱硫工程为蓝本介绍了该项目的背景,重点介绍了氨法烧结烟气脱硫在日钢的应用情况,针对日钢烧结烟气的特点分析了氨法烧结烟气脱硫在日钢应用中出现的主要问题、产生原因以及解决措施,借此对氨法烧结烟气脱硫系统的设计提出建议,最终实现氨法烧结烟气脱硫应用的成熟和完善。     

燃煤炉预混-喷钙二段脱硫技术探讨

当前对燃煤炉进行脱硫处理所采取的技术方案多以燃煤炉尾部烟气脱硫技术为主。该技术方案虽然具有一定的脱硫效果,但投资成本较高。文章从燃煤炉脱硫的角度入手,研究了一种基于预混-喷钙二段脱硫技术,并就该技术在脱硫方面的主要机制进行了研究探讨,配合实验分析的方式,论证了燃煤炉预混-喷钙二段脱硫技术的实施效果,希望能够引起各方关注与重视。     

钠碱法两级塔脱硫技术

文章介绍了永清环保股份有限公司在锦州新华龙钼业股份公司建设的一套用钠碱法两级塔脱硫技术,治理五期回转窑烟气SO2含量20 000 mg/Nm3的成功案例,描述了钠碱法两级塔脱硫技术的整个工艺流程和列举了主要设备。经运行实践证明,环保效果明显,脱硫装置脱硫效率大于98%,脱硫副产品亚硫酸钠品质大于93%。     

改进型石灰-石膏法脱硫工艺在糠醛厂的应用

文章通过某糠醛厂糠醛渣锅炉烟气脱硫实例,介绍了改进型石灰-石膏法脱硫工艺流程、工艺特点及脱硫效果,对该糠醛厂脱硫系统运行过程中存在的问题进行了分析,并提出了改进措施,为相同类型糠醛锅炉烟气治理提供了设计和运行经验。     

关于脱硫系统取消烟气旁路的分析

取消烟气旁路系统已成为当今脱硫系统的一个趋势,很多文献介绍取消旁路系统的好处。针对旁路系统取消的原因、取消后应采取的补偿措施、以及如何进行整体规划等实际问题,本文提出几点不同看法。     

中小型燃煤锅炉烟气脱硫技术现状及趋势

文章分析了常用的烟气脱硫技术,以我国中小型燃煤锅炉(≤65t/h)为研究对象,分析了其烟气脱硫技术的应用现状,结合工程实践经验,提出其未来发展趋势。     

石灰石—石膏湿法脱硫中结垢堵塞等问题的探讨

目前,石灰石—石膏法作为火电厂烟气脱硫工程技术规范之一,具有工艺技术成熟、运行可靠、应用广泛的特点,在火电厂烟气脱硫行业中占据着主导地位。但在实际工程运行中,仍存在着一些问题。文章针对其工程应用中存在的结垢堵塞和脱水困难等问题进行了探讨。     

烟气脱硫中pH值对脱硫过程的影响

湿法石灰石-石膏烟气脱硫系统(即FGD系统)目前在国内外燃煤电站FGD系统中占绝对优势。FGD的目的是用化学方法除去烟气中的二氧化硫而使烟气得以净化。pH值作为石膏浆液酸碱度的度量,是脱硫工序中一项重要的技术参数,同时可作为一项与化学反应相关的环境指标。石灰石利用率、脱硫效率和石膏浆液品质等与pH值的控制密切相关。通常我们通过控制石灰石(CaCO3)掺加量来控制pH值,要提高pH值,可增加石灰石添加量,反之则减量。运行中,必须维持pH值的稳定性。pH值升高会提高系统碱度和脱硫效率,但石灰石利用率会相应降低,并加速垢的生成,最终影响石膏品质。降低pH值会提高系统酸度,同时提高石灰石利用率,并加速石膏晶体析出,但会加速系统腐蚀,造成系统运行不稳定,脱硫效率也会大大降低。因此,浆液pH值的控制应在达到要求脱硫率的前提下谋求最佳值。一般控制pH在5.0-5.8为最佳范围。     

Taking ‘Don’t Knows’ as Valid Responses: A Multiple Complete Random Imputation of Missing Data

Incomplete data is a common problem of survey research. Recent work on multiple imputation techniques has increased analysts’ awareness of the biasing effects of missing data and has also provided a convenient solution. Imputation methods replace non-response with estimates of the unobserved scores. In many instances, however, non-response to a stimulus does not result from measurement problems that inhibit accurate surveying of empirical reality, but from the inapplicability of the survey question. In such cases, existing imputation techniques replace valid non-response with counterfactual estimates of a situation in which the stimulus is applicable to all respondents. This paper suggests an alternative imputation procedure for incomplete data for which no true score exists: multiple complete random imputation, which overcomes the biasing effects of missing data and allows analysts to model respondents’ valid ‘I don’t know’ answers.     

Combining research techniques to improve quality service in hospitality

Hospitality research includes many studies that combine and revisit the quantitative–qualitative debate, and review the arguments for and against using mixed-methods. The aim of this paper is to demonstrate the application of qualitative methodologies based on the combination of techniques which also include quantitative elements in addition to those pertaining to qualitative techniques. The research aims to specifically identify the most important managerial factors which, from the point of view of hotel chain executives, serve to improve the quality of the service they provide. The techniques used are concept mapping and qualitative optimization, both of which are qualitative methodologies though they include quantitative elements to overcome the subjectivity deficits typically found in qualitative methodologies. In addition, the combination of both techniques leads to greater precision of the results obtained. Our methodological proposal combines concept mapping with qualitative optimisation, thereby improving the prioritisation and hierarchical ordering of the ideas obtained and structured. Instead of working with each cluster’s average score in terms of importance (as defined within the concept mapping model), our contribution is based on prioritising these based on their distance to the optimal reference. This allows for experts’ evaluations of each idea in terms of its importance to not be strictly quantitative, that is, the experts are not obligated to assign numbers to their evaluations; rather, they can assess ideas based on qualitative labels.     

Design and investigation of EWMA and double EWMA with quadratic process model in R2R controllers

In the last few years, “Run-to-Run” (R2R) control techniques have been developed and used to control various processes in industries. These techniques combine control engineering and statistical process control techniques. The R2R controller is basically consists of a linear regression model that relates the input variables to the output variables using Exponentially Weighted Moving Average (EWMA) or double EWMA (dEWMA) scheme. In this paper, we have developed a quadratic R2R controller model as an extension of Box, Luceno and Del Castillo models. The validity and performance of the developed models were tested in the magnetic ceramic process. By this study we have found that the quadratic model improves capability of process and applying dEWMA procedure decreases variance of the response variables. The results of the study shows that the quadratic R2R control models outperform linear R2R controls in the certain manufacturing process.     

An examination of estimation and specification error biases in estimates of option prices generated by Black-Scholes and Cox-Ross models

In this paper the author identifies and examines the estimation and specification error biases of the Black-Scholes and Cox-Ross models by using both analytical and monte-carlo simulation techniques. Several hypotheses are tested. The central hypothesis is whether or not the estimation error bias in the correctly specified model is large enough to make researchers mistakenly pick the “wrong” model as being the “correct” one. The findings in this study support this hypothesis. It is shown that there is a bias toward accepting the Cox-Ross model as correct, even if the Black-Scholes is assumed to be the true model for pricing options.     

Revolution, evolution, or status quo? Guidelines for efficiency measurement in health care

This paper discusses ways forward in terms of making efficiency measurement in the area of health care more useful. Options are discussed in terms of the potential introduction of guidelines for the undertaking of studies in this area, in order to make them more useful to policy makers and those involved in service delivery. The process of introducing such guidelines is discussed using the example of the development of guidelines in economic evaluation of health technologies. This presents two alternative ways forward—‘revolution’, the establishment of a panel to establish initial guidelines, or ‘evolution’—the more gradual development of such guidelines over time. The third alternative of ‘status quo’, representing the current state of play, is seen as the base case scenario. It is concluded that although we are quite a way on in terms of techniques and publications, perhaps revolution, followed by evolution is the way forward.