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1、,Chapter 2 Boiler,2.1 Introduction,Boilers use heat to convert water into steam for a variety of applications. Primary among these are electric power generation and industrial process heating. Steam has become a key resource because of its wide availability, advantageous properties and nontoxic natu
2、re.,The steam flow rates and operating conditions can vary dramatically: from 1000 lb/h (0.126kg/s) in one process use to more than 10 million lb/h (1260kg/s) in large electric power plants; from about 14.7 psi (1 bar) and 212(100) in some heating applications to more than 4500 psi (310 bar ) and 11
3、00(593) in advanced cycle power plant.,锅炉利用热量使水转变成蒸汽以进行各种利用。其中主要是发电和工业供热。由于蒸汽具有有利的参数和无毒特性，因此蒸汽作为一种关键的工质（资源）被广泛的应用。 蒸汽流量和运行参数的变化很大：从某一过程里1000磅/小时（0.126kg/s）到大电厂超过10106磅/小时（1260 kg/s），压力从一些加热应用的14.7 psi (1.0135bar), 212 （100）到先进循环电厂的4500 psi （310bar）1100 （593）。,Criteria n. 标准 Utility boiler 电站锅炉 Utili
4、ty-type unit 电站型机组，大型机组 Reheater n. 再热器 cycle efficiency 循环效率,Modern steam generating systems can be classified by various criteria. These include end use, firing method, operating pressure, fuel and circulation method.,Utility boilers are used primarily to generate electricity in large central powe
5、r stations. They are designed to optimise overall thermodynamic efficiency at the highest possible availability. A key characteristic of newer units is the use of a reheater section to increase overall cycle efficiency.,现代蒸汽发生系统可根据不同的标准分类。这些包括最终用途、燃烧方式、运行压力、燃料和循环方式。大型中心电站的电站锅炉主要用来发电。经过优化设计，使最大可能可用性时
6、有最高的热效率。新机组的关键特性是利用再热器提高整个循环效率。,A variety of additional systems also produce steam for power and process applications. These systems usually take advantage of low cost or free fuels, a combination of power cycles and processes, and recovery of waste heat in order to reduce overall costs. Examples of
7、 these include:,各种附加的系统也产生蒸汽用于发电及过程应用。这些系统常常利用廉价或免费燃料，联合动力循环和过程，余热回收以减少总费用。这些例子包括：,Pressurized fluidised-bed combustion (PFBC) Includes higher pressure combustion with gas cleaning and expansion of the combustion products through a gas turbine.,Integrated gasification combined cycle (IGCC) Adds a co
8、al gasifier to the CC to reduce fuel costs and minimize airborne emissions.,Gas turbine combined cycle (CC) Advanced gas turbines with heat recovery steam generators as part of a bottoming cycle to use waste heat recovery and increase thermal efficiency.,Pressurized fluidised-bed combustion (PFBC) I
9、ncludes higher pressure combustion with gas cleaning and expansion of the combustion products through a gas turbine.,Blast furnace hood heat recovery Generates steam using the waste heat from a blast furnace.,Solar steam generator Uses concentrators to collect and concentrate solar radiation and gen
10、erate steam.,燃气轮机联合循环（CC）带有余热回收蒸汽发电机作为基本循环一部分的高级燃气轮机以利用余热并提高热效率。,整体煤气化联合循环（IGCC）：在CC基础上增加煤气化以降低燃料费用并将污染排放降到最低。,增压循环流化床燃烧（PFBC）：在更高压力下燃烧，包括燃气净化，以及燃烧产物膨胀并通过燃气轮机做功。,高炉排烟热量回收：利用高炉余热产生蒸汽。,太阳能蒸汽发生器：利用集热器收集太阳辐射热产生蒸汽。,2. 2 Development of Utility Boiler,The modern 660MW coal-fired boiler has some 6000 tons o
11、f pressure parts which include 500 km of tubing, 3.5 km of integral piping and 30000 tube butt welds.,It is the culmination of some fifty years development and while the basic concept of pulverized fuel firing into a furnace lined with evaporator tubes, with the combustion gases then passing over co
12、nvection superheater and heat recovery surface, has remained unchanged, the advancement of steam conditions, increases in unit size and the properties of the fuel fired have required major changes in materials employed, fabrication techniques and operating procedures.,现代660MW燃煤锅炉有大约6000吨的压力部件，包括500千
13、米的受热面管材，3.5千米连接管与联箱和30000个管接头焊口。这是经过大约50年发展的结果，并形成了煤粉在具有蒸发管束的炉膛燃烧，烟气然后流经对流过热器和热回收表面的基本概念并保留至今。蒸汽参数的提高，机组容量的增大及燃料燃烧特性的改进都要求在材料、制造技术和运行程序上相应发展。,In the years immediately following the Second World War, it was customary to install in a power station, a greater number of boilers than turbines, the boiler
14、s feeding a range to which the turbines were connected.,This arrangement reflected the inferior availability of boilers compared with turbines, but increase in boiler availability in the late 1940s led to the acceptance of unitized boilers and turbines.,The change to unitized boiler and turbine allo
15、wed reheat to become practicable and, with the availability of high temperature steels, there followed a continuous advance in steaming conditions to the current standard cycle of 2400 lbf/in2( 165.5bar), 568 with reheat to 568.,To take full advantage of the more advanced steam conditions and to obt
16、ain the economies of size, the next fifteen years also saw a twenty-fold increase in unit size.,二战后的一些年里，在电厂安装锅炉的数量多于汽轮机是很常见的，锅炉提供蒸汽到母管然后到汽机。这种布置反应了锅炉的可用性低于汽轮机。四十年代后期，随着锅炉可用性的提高，锅炉和汽机开始可以相互配套使用。锅炉和汽机成套的变化使得再热成为可行，而且伴随着高温钢材的应用，经过蒸汽参数的不断提高，达到了当前的标准循环2400lbf/in2(165.5bar)，568和再热568。为充分利用更高的蒸汽参数和获得经济容量，
17、在接下来的15年，机组容量又增加了20倍。,A utility normally procures plant from specialist manufacturers who have responsibility for design, manufacture,erection and commissioning. While the manufacturers carry out development of manufacturing processes and continuously update their design methods, and change in operating conditions and size necessarily results in a new plant being of a prototype nature.,
