凤台电厂脱硫烟气工程烟囱型式及防腐工艺

介绍了安徽凤台电厂一期工程2台600MW机组和二期工程待建2台600MW机组的烟囱选型及防腐工艺,其中一期工程采用的是2台机组合用一根210m的套筒烟囱,脱硫后配置回转式烟气-烟气加热器(GGH);二期工程选用的是240m双筒集束烟囱,内筒采用钢内筒,脱硫后不采用GGH。从安全性、合理性及可靠性等方面对目前烟囱的防腐工艺进行了探讨和比较。     

排放湿烟气烟囱的钢内筒设计探讨

针对目前燃煤电厂采用湿式石灰石-石膏法脱硫工艺取消烟气加热装置的烟囱设计存在的问题,分析了排烟参数的变化对钢内筒防腐的影响。通过对某电厂三期工程的设计实践,对钢内筒设计有关问题进行探讨:排烟参数对钢内筒设计的影响十分复杂,烟囱设计中环保、土建、热机专业应密切协调配合,核算钢内筒的内直径、流速、沿程阻力,以满足烟囱全负压运行。建议了不同内衬应控制的烟气流速限值,保证排放湿烟气的烟囱安全可靠运行。     

1 000MW燃煤机组湿烟囱防腐方案

我国燃煤电厂烟气中的SO2排放控制主要采用湿法脱硫技术,脱硫后的烟气中仍含有少量的SO2和大部分SO3,不设烟气再热器（gas-gas heater,GGH）时烟囱内烟气湿度大,属于湿烟囱,应按强腐蚀性等级考虑。从防腐角度来看,烟囱结构形式的首选方案是多管式烟囱。通过对圆筒、方筒和塔架3种烟囱外筒形式的比较,得出采用普通圆形钢筋混凝土外筒最优的结论。通过对钛钢复合板内筒、玻璃钢内筒、镍基合金内衬和宾高德防腐玻璃砖内衬钢内筒这几种湿烟囱防腐方案的对比分析,优先推荐玻璃钢内筒作为1 000MW燃煤机组湿烟囱防腐方案。     

湿法脱硫后烟囱出口烟气液滴夹带问题分析及解决

对燃煤电厂湿法脱硫后烟囱出口烟气液滴夹带现象的成因进行了探讨;分析了该现象对烟囱周边环境的负面影响;主要针对“湿烟囱”提出通过控制烟囱内烟气流速、采用合理的筒型设计和设置液滴回收装置等措施,以解决其出口烟气液滴夹带问题。     

镍基及钛合金在湿法脱硫钢烟囱防腐中的应用

火电厂烟气脱硫系统中,脱硫后尾部烟道及钢烟囱产生腐蚀的原因是含硫量、卤化物、冲刷腐蚀作用、结露液滴形成硫酸等因素形成。镍合金可用于烟道及烟囱筒体的防腐,如C-926、C-31、C-625、C-276、C-59等合金;烟道及烟囱防腐中还可应用钛合金,国内有电厂采用钛复合板为钢烟囱内筒材料。由于各电厂脱硫系统的情况不同,防腐材料的选择应根据具体情况确定。     

湿法脱硫烟囱防腐改造建议及改造实例

论述了湿法脱硫后烟气对烟囱的腐蚀机理,对几种烟囱防腐改造的选型进行了分析,指出宾高德内衬系统适合泡沫玻璃砖钢内筒的防腐改造,杂化聚合结构类适合涂料类或砖类钢内筒的防腐改造,钛钢复合板钢内筒适合新建烟囱应用.详细介绍了一种湿法脱硫烟囱防腐改造实例,经实际运行后现场检查,烟囱整体防腐效果良好.     

吊挂式烟囱钢内筒施工方案

新建火力发电厂的烟气处理多采用湿法脱硫方式,该法产生的酸水对烟囱内壁防腐提出了更高的要求,因此,耐腐蚀较好的钢内筒开始在烟囱设计中广泛使用。悬吊式烟囱钢内筒节约钢材,利于外筒设计,已成为近几年设计的优选方案。天津北疆发电厂烟囱工程钢内筒设计为悬吊式,采用气压顶升倒装法施工,保证了安全和工期,获得了较好的经济效益。     

某电厂单筒式钢筋混凝土烟囱腐蚀调查分析

国内某电厂脱硫方式由干法改为湿法,且未设烟气再热装置,烟囱出现明显腐蚀现象。对该厂单筒式钢筋混凝土烟囱的筒身外观、混凝土、钢筋、内衬、 腐蚀性介质等进行了调查,对其安全性和耐久性进行了评定, 腐蚀性等级评价结果为： 该电厂在采用石灰石-石膏湿法烟气脱硫且无烟气再热（GGH）系统运行条件下,烟囱腐蚀等级为强腐蚀。在调查研究的基础上,提出了湿烟囱排气筒在防腐设计、施工与运行管理等方面的建议,特别提出对烟囱系统加强维护的观点,以实现烟囱系统全寿命周期内的可靠运行。     

玻璃钢排烟内筒在华能轮台电厂的实际应用探讨

华能轮台电厂350MW脱硫技术采用湿法脱硫(F G D)且不加装烟气加热系统(G G H)工艺,该机组所使用的烟囱内筒为玻璃钢材质,相对其它材质烟囱而言,玻璃钢烟囱具有质轻、高强、耐腐蚀、隔热绝缘、施工周期短、不需要维修、使用寿命长等优点,在F G D系统中具有较多的应用优势,很好地应对了经过湿法脱硫后烟囱对耐腐蚀、耐高温的较高要求,特别适合像该电厂作为燃煤电厂脱硫不加GGH的湿烟囱运行条件,为其他电厂湿烟囱运行提供参考借鉴。     

湿法脱硫烟囱防腐方案选择

介绍了目前火电厂常用的湿法脱硫(FGD)烟囱防腐工艺,包括钢内筒+发泡玻璃砖、钢内筒喷涂涂料、钛钢复合板和玻璃钢内筒等防腐方案。给出了不同工艺的优、缺点和适用范围,并进行了技术经济比较。分析表明,玻璃钢材料具有优良的耐腐蚀性和较高的技术经济性,在国外已有较多的使用案例和成熟的设计安装经验,可作为FGD烟囱理想的内筒材料。     

关于烟囱防雷设计标准中存在差异的探讨

目前 ,国内、外对电厂烟囱防雷设计已制定了相关标准 ,但各种防雷标准存在一些差异。结合国外烟囱防雷的设计 ,对顶部避雷针的选择和布置、烟囱防雷系统引下线的布置、烟囱防雷系统导体和钢筋的连接、钢内筒烟囱防雷系统的连接进行了叙述 ,阐明了电厂烟囱防雷设计相关标准的应用。     

240 m烟囱钢内筒气压顶升倒装施工法

合肥皖能发电厂5号机组为600 MW超临界燃煤机组,该机组的烟囱为240 m的单套筒式结构。 在该烟施工中采用气顶装置使烟囱钢内筒缓慢起升。 介绍了钢内筒气顶装置的安装与布置,钢筒体采用倒装法安装方法以及气顶作业的施工方法。     

西门子百万等级超超临界机组凝汽器结构分析

介绍了西门子百万等级下排汽凝汽器技术,针对该凝汽器结构,陈述了该类型凝汽器的设计特点,并作了对比分析.西门子下排汽凝汽器与汽机低压缸采用刚性连接,低压缸外缸与凝汽器喉部直接焊接.汽轮机低压缸内缸通过轴承座直接支撑在基础上.凝汽器底部采用多球轴承座与基础焊接,并在底部基础上布置定向导轨,定位凝汽器在水平面沿正交方向膨胀.西门予公司下排汽凝汽器管束采用特有的低密度管束布置,具有专利技术的对称布王形式,其传热效果好,除氧效果尤佳,凝结水过冷度低.     

Concept of turbines for ultrasupercritical,supercritical, and subcritical steam conditions

The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder’s inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.     

1000MW机组汽轮机启动方式及旁路系统的选择

为选择邹县电厂1 000 MW超超临界机组汽轮机的启动方式和旁路系统的配置方式,进行了技术分析和经济比较。从技术和安全性考虑,高压缸启动和中压缸启动均可行。在运行安全方面,高压缸启动的系统简单、故障率低;在经济上,高压缸启动只需配置高压一级大旁路,系统大大简化,与中压缸启动比可节省大量初期投资。通过分析、比较,确定邹县发电厂1000MW超超临界机组汽轮机采用带高压一级简化大旁路的高压缸启动方式。     

A novel low power and high speed double edge explicit pulse triggered level converter flip‐flop

One of the effective ways to reduce power consumption is using clustered voltage scaling technique. The level converter flip‐flop is needed to control static current when the block with Low Supply Voltage (VDDL) drives the block with High Supply Voltage (VDDH). One of the big challenges of design is that level converter flip‐flop has low power and high speed. In this paper, pulse triggered level converter flip‐flop and double edge pulse generator were proposed. This level converter flip‐flop used conditional data mapping technique for reducing power consumption. An explicit double edge pulse generator could be shared among several level converter flip‐flops so that power consumption would be reduced. Also, the number of stack transistor was reduced in the discharging path that causes delay decrease. The simulation results showed that the proposed flip‐flop reduced 20% of power consumption and 17% of delay in comparison with other flip‐flops at 50% data switching activity. Copyright © 2013 John Wiley & Sons, Ltd.     

Development of a 400 kJ Nb3Sn superconducting magnet for an SMES system

An Nb₃Sn superconducting magnet to store 400 kJ was developed as a unit magnet for a 2.4-MJ SMES system used for stabilization studies of electrical power systems. The superconducting magnet consists of a cryostat and an Nb₃Sn coil. The dimensions of the coil are: 340 mm inner diameter, 700 mm outer diameter and 177 mm axial length. The pool-cooled coil is a stack of 20 Nb₃Sn double pancakes, and the cooling channels are aligned between pancake coils. To reduce Joule loss in electrical power converters, the maximum operating current of the coil is designed to be 350 A, which is one order of magnitude less than the operating currents of similar scale coils for pulse use. The conductor is an Nb₃Sn monolithic conductor with cross section 1.50 × 2.38 mm. For good superconducting stability and high dielectric strength of the coil, the Nb₃Sn double pancakes were wound by the react-and-wind technique. Operation of dc current to 105% (367.5 A) of the design operating current was achieved without quench. After the whole of the coil was exposed out of liquid helium, the coil did not quench under 120 A current operation for more than 2 hours. It was verified that the coil was stable for the SMES system. © 1998 Scripta Technica, Inc. Electr Eng Jpn, 121(3): 44–52, 1997     

电厂湿法烟气脱硫工程临时烟囱的设计

在燃煤电厂烟气脱硫技改项目中,因不设烟气换热器而需要对原烟囱进行防腐改造:为了解决因施工影响主机运行的难题,需要设置临时烟囱;通过渭河电厂技改工程,介绍了临时烟囱的设计方法,该方法可为类似工程提供参考.