教学教案讲义余热锅炉及蒸汽热风系统.doc

此文档收集于网络，如有侵权，请联系网站删除第七章 余热锅炉及蒸汽热风系统7.1 锅炉的基本知识7.1.1 锅炉的定义及分类锅炉是利用燃料燃烧释放的热能或其它热能将工质(水或其它流体）加热到一定参数的设备。作为锅炉种类之一的余热锅炉不使用燃料,专门回收工业生产过程中的高温烟气余热、化学反应余热、可燃废气余热及高温产品余热,既节约了能源,又可满足下道工序的要求。7.1.1.1 锅炉的分类锅炉按其用途可分为电站锅炉、工业锅炉、船舶锅炉和机车锅炉,前两类因为是安装在固定基础上不可移动的,又统称为固定式锅炉。还可从其它角度出发对锅炉进行分类和命名。锅炉的名称可以反映出其某个方面的特征。具体见表7.1 锅炉分类分 类 方 法锅 炉 分 类工种种类及输出状态蒸汽锅炉、热水锅炉、特种工质锅炉锅炉出口蒸汽压力低压锅炉、中压锅炉、高压锅炉、超高压锅炉、亚临界压力锅炉、超临界压力锅炉燃料或能源燃煤锅炉、燃油锅炉、燃气锅炉、混合燃料锅炉、特种燃料锅炉、余热锅炉、新能源锅炉燃烧方式火床燃烧锅炉（又称层燃锅炉、炉排锅炉）、火室燃烧锅炉（又称悬浮燃烧锅炉、燃煤者也叫煤粉锅炉）、旋风燃烧锅炉、沸腾燃烧锅炉排渣方式固态排渣锅炉、液态排渣锅炉炉内烟气压力负压燃烧锅炉、微正压燃烧锅炉、增压燃烧锅炉通风方式自然通风锅炉、机械通风锅炉锅炉本体结构类型锅壳锅炉（内分卧式和立式）、水管锅炉（内分单锅筒式、双锅筒式按锅筒布置又分纵置式、横置式等）、铸铁锅炉锅炉本体布置型式D型布置、H型布置、塔型布置、箱体布置工质要锅炉内部流动方式自然循环锅炉、强制循环锅炉、直流锅炉、复合循环锅炉、低循环倍率锅炉运输安装方式快装锅炉、组装锅炉、散装锅炉锅炉在厂内布置方式露天锅炉、半露天锅炉、室内锅炉7.1.1.2 余热锅炉分类适合于烟气条件恶劣,烟尘较多的余热锅炉的总体结构,基本上可分为两种形式,即多烟道式和直通式。1. 多烟道式余热锅炉多烟道式余热锅炉一般分为四个烟道。第一烟道是一个大的辐射冷却室,烟气在其中被冷却到烟尘的软化点以下,烟气中的大部份烟尘凝结成固体颗粒后被分离下来。第二、三、四烟道是对流受热区，在这里垂直挂着一排排与烟气成纵向冲刷的屏式受热面。2. 直通式余热锅炉直通式余热锅炉的辐射冷却室和对流区呈直线状连接,烟气是水平方向流动。辐射冷却室体积庞大,内壁全是翅片管,烟尘在其冷却到烟尘的凝固点以下，在有色冶金用的余热锅炉中，一般冷却到650左右，才进入后面的对流受热区。对流区内壁也是翅片管，中间分段悬挂屏式受热面。各屏之间的距离,靠近辐射室最近的几排(凝渣管）间距较大，其后的各区段间距较小。直通式余热锅炉在高温区及烟尘易粘附区设置了振打除尘。多烟道和直通式余热锅炉一般都采用强制循环形式。7.1.1.3 锅炉的规格与型号1. 蒸汽锅炉性能标志锅炉的性能以其供热能力和供热品位为标志。蒸汽锅炉的供热能力用“额定蒸发量”表示，单位为t/h。额定蒸发量有时也叫做额定出力，铭牌蒸发量或锅炉容量。额定蒸发量是在额定出口蒸汽参数和额定给水温度,使用设计燃料和工业过程余热并在保证设计效率的条件下连续运行所应达到的每小时产汽量。蒸汽锅炉的供热品位用额定出口蒸汽压力和温度表示。7.1.2 锅炉的工作过程及基本构成7.1.2.1 锅炉的工作过程锅炉的工作过程就是在锅炉内进行一系列的能量转换和转移过程。具体过程如下:1. 燃料的炉内燃烧,燃料的化学能以热能的形式释放出来,使火焰和烟气具有高温。2. 高温火焰和烟气的热量通过受热面向被加热介质传递。3. 水被加热至沸腾而汽化,成为饱和蒸汽,再经加热面成为过热蒸汽。燃料燃烧,火焰和烟气向工质传热,工质的加热和汽化是三个互相关联而又同时进行的过程,是使用燃料的锅炉的主要工作过程。余热锅炉的工作过程无燃料燃烧一项,取而代之的是不断接受工业过程烟气及高温产品带入的余热。能量转换和转移过程是与物质运动相结合的,即:1. 给水进入锅炉,最后以饱和蒸汽或过热蒸汽(对于热水锅炉则是热水）形式输出。2. 煤进入炉内燃烧,其可燃部分燃烧后连同原含水分转化为烟气,原含灰分则残存为灰渣。3. 风送入炉内参加燃烧反应,过剩的空气也混入烟气中排出。作为锅炉主要系统的水汽系统,煤灰系统,风烟系统的工作也是同时连续地进行。它们是一个有机的整体，缺一不可，任一系统故障，都将导致全系统停止运转。7.1.2.2 锅炉的基本构成锅炉的核心构成部分是“锅”和“炉”。锅是容纳水和蒸汽的受压部件,包括锅筒(也叫汽包）、受热面、集箱(也叫联箱）和管道等,其中进行着水的加热、汽化及汽水分离等过程。炉是燃烧的场所,即燃烧设备和燃烧室(炉堂）。锅和炉是由传热过程联系起来的,受热面即是锅和炉的分界面。凡是一侧有放热介质(火焰、烟气）,另一侧有受热介质(水、蒸汽、空气）,进行着热量传递的壁面称为受热面。2. 工业蒸汽锅炉的型号表方法为:型号代号 变型设计次序燃烧方式 燃料品种额定蒸汽量 过热蒸汽温度（饱和蒸汽则不写此项） 出口蒸汽压力锅炉型式代号表7.2。燃料方式代号见表7.3。燃料品种代号见表7.4表7.2 锅炉型号代号 表7.3 燃料方式代号 锅壳锅炉立式水管型燃烧方式代号燃烧方式代号固定炉排G抛煤机P活动手摇炉排H下饲炉排A链条炉排L倒转炉排加抛煤机D振动炉排Z往复炉排W沸腾炉F单沸腾炉B室燃炉S旋风炉XLS立式火管型LH卧式外燃型WW卧式内燃型WN水管锅炉单锅筒纵置式DZ单锅筒横置式DH单锅筒立置式DL双锅筒纵置式SZ双锅筒横置式SH纵横锅筒式ZH强制循环式QX表7.4 燃料品种代号燃料品种代号燃料品种代号类石煤、煤矸石S褐煤H类石煤、煤矸石S贫煤P类石煤、煤矸石S水柴M类无烟煤W稻D类无烟煤W甘蔗渣D类无烟煤W油Y类烟煤A汽Q类烟煤A油母页岩Ym类烟煤A受热面从放热介质吸收热量并向受热介质放出热量。凡是以主要辐射换热的方式吸收放热介热量的受热面称为辐射受热面。而主要以对流换热的方式吸收热介质热量的受热面则称为对流受热面。辐射受热面布置在炉膛内;对流受热面布置在炉膛出口以后、烟气温度较低的烟道内。布置对流受热面的烟道称为对流烟道。由锅筒、受热面及其间的连接管道与烟风道、燃烧设备和出渣设备、炉墙和构架(包括平台、扶梯）等所组成的整体称为锅炉本体。由锅炉本体、锅炉范围内的水汽烟风燃料管道及其附属设备、测量仪表、其它的锅炉附属机械等构成的整套装置称为锅炉机组。水位计、压力表、安全阀称为锅炉的三大安全附件。7.1.3 水蒸汽及其热力性质。 7.1.3.1 水蒸汽的基本概念 1. 饱和状态 在水的汽化和水蒸气凝结的过程中,当单位时间内逸出液面与回到液面的分子等相等,汽液两相平衡共存时,此种状态称为饱和状态。 饱和状态下蒸汽和水的压力、温度称为饱和压力和饱和温度。对应于一定的饱和压力,有一定的饱和温度。 处于饱和状态下的蒸汽和水,分别称为饱和蒸汽和饱和水。饱和蒸汽与饱和水的混合物称为湿饱和蒸汽。在湿饱和蒸汽中,饱和蒸汽所占的质量份额(或重量份额）称为干度,用符号X表示不含饱和水的饱和蒸汽称为干饱和蒸汽,其干度为1。饱和水的干度为零。 2. 过热蒸汽 温度高于与其压力所对应的饱和温度时,称为过热蒸汽。 过热蒸汽温度与相应于其压力的饱和温度之差值称为过热度。3. 过冷水(未饱和水温度低于与其压力所对应的饱和温度和水称为冷水或未饱和水。相应于过冷水压力的饱和温度与其温度之差值称为过冷度。4. 水的定压加热与汽化过程 水在锅炉中的加热、汽化过程可以近似地视为定压过程。定压下的水蒸汽发生过程分为三个阶段: 1） 水的预热 将过冷水加热,使之达到饱和温度,成为饱和水。1kg过冷水变为饱和水所需吸收的热量称为过冷水的欠热。 2） 水的汽化 继续加热饱和水,开始产生蒸汽,构成湿饱和蒸汽,而且干度越来越大,最终变为干饱和蒸汽,汽化阶段结束。lkg饱和水汽化成为干饱和蒸汽所需的热量称为水的比汽化潜热。汽化阶段不仅是定压过程,同时也是定温过程。汽化在饱和压力、饱和温度下进行。3） 蒸汽的过热 继续加热干饱和蒸汽,可以使其温度升高而成为过热蒸汽。lkg干饱和蒸汽由饱和温度加热到过热温度所需的热量称为过热热量。5. 临界参数 水的饱和压力与饱和温度是单值函数关系。压力增高,相对应地饱和温度也增高。比汽化潜热也随压力而变化,随着压力的增高,比汽化潜热逐渐减少。 当压力增高达到临界压力值时,水的汽化阶段缩为一点,比汽化潜热为零,此时的温度为临界温度。 水的临界压力为225.51ata,临界温度为374.12,临界比容为0.003147m3/kg。 在临界压力以上,水和汽的差别消失。 7.1.3.2 水和蒸汽的热力性质表 表7.5、表7.6(分别以温度和压力为基准两表）为饱和水和干饱和蒸汽的热力性质表。表7.7 为未饱和水的比容和比焓表。表7.8为过热蒸汽的比容和比焓表。 表7.9为水和蒸汽的导热系数表。表7.10为水和蒸汽的动力粘度系数表。表7.11为水和蒸汽的物理性质准则为Pr数表。 表7.5 饱和水和干饱和蒸汽势力性质表（以温度为基准） 温度饱和压力比容（m3/Kg）比焓（Kcal/Kg）比热Kcal/Kg K）Kg/cm2mmHgVVhhr= h-hss0.010.006234.60.0010002206.160.00597.5597.50.00002.187250.00896.50.0010000144.165.02599.7594.70.01822.1560100.012519.20.0010003106.4310.03601.9591.80.03612.1262150.0173812.80.001000877.9815.03604.1589.00.05362.0977200.0238317.50.001001757.8420.03606.2586.20.07082.0704250.0322823.70.001002943.4025.02608.4583.40.08772.0443300.0432531.80.001004332.9330.01610.6580.60.10432.0193350.0573242.20.001006025.2435612.7577.70.12061.9954400.0752055.30.001007819.5540614.9574.90.13661.9725450.0977171.90.001009915.2844.99617572.00.15251.9504500.1257892.50.001012112.0549.98619.1569.10.16801.9293550.16051118.10.00101459.57954.97621.2566.30.18341.9090600.20313149.10.00101717.679959.97623.3563.30.19851.8895650.2550187.00.00101996.20264.97625.4560.470.21341.8707温度饱和压力比容（m3/Kg）比焓（Kcal/Kg）比热Kcal/Kg K）Kg/cm2mmHgVVhhr= h-hss700.3178233.70.00102285.04669.98627.4557.50.22811.8526750.3931289.10.00102594.13474.98629.5554.50.24251.8352800.4829355.20.00102923.40979.99631.4551.50.25681.8181850.5894433.650.00103262.82985.01633.4548.40.27091.8022900.7149525.90.00103612.36190.03635.4545.30.28481.7865950.96196340.00103991.98295.06637.3542.20.29861.77141001.0332760.00.00104371.673100.1639.2539.10.31211.75681101.46090.00105191.210110.2642.8532.60.33881.72901202.02460.00106060.8915120.3464.3526.00.36491.70281302.75460.00107000.6681130.5649.6519.20.39041.67811403.6850.00108010.5085140.7652.8512.10.41541.65481504.8540.00109080.3924151.0655.7504.70.43991.63271606.3030.00110220.3068161.3658.4494.10.46401.61161708.0760.00111450.2426171.8660.9489.10.48761.591418010.2240.00112750.1938182.3663.1480.80.51101.572120015.8550.00115650.1272203.6666.6463.00.55671.535222023.6560.00119000.8604225.4668.7443.40.601471.535224034.1380.00122910.05965247.8669.3396.80.68901.466726047.8690.00127560.04213271.167.9396.80.68901.433328065.4680.00133240.03013295.4664.1368.10.73291.399330087.6210.00140410.02165321.3654.1335.80.77751.3634340148.930.00163870.01078381.1627.2216.20.87461.2761360194.430.00189590.006940421.4593.6172.30.93651.2086374.15225.560.0031700.003170503.3503.301.06121.0612注：表7.5(以温度和压力为基准两上表中, V hs为饱和水的值. Vhs为饱和汽的值.r为潜热或蒸发热。 表7.6 饱和水和干饱和蒸汽热力性质表(以压力为基准）饱和压力温度比容（m3/Kg）比焓（Kcal/Kg）比热Kcal/Kg K）Kg/cm2VVhhr= h-hss0.016.700.0010001131.626.72600.4593.70.02432.14570.0323.760.001002646.5223.80607.9584.10.08362.05060.0532.550.001005128.7232.56611.7579.10.11262.00700.0738.60.001007320.9138.66614.3575.60.13241.97850.1045.450.001010114.9545.44617.2571.80.15391.94850.259.670.00101707.79159.64623.2563.50.19751.89070.368.680.00102215.32668.65626.9558.20.22421.81560.580.860.00102983.30080.86631.8550.90.25931.81560.789.470.00103572.40889.47635.1545.70.28331.78821.099.090.00104301.72599.17638.8539.60.30971.75942119.620.00106030.9018119.9646.2526.30.36391.70383132.880.00107280.6168133.4650.6514.10.39761.67134142.920.00108310.4708143.7653.7510.00.42261.64825151.110.00109200.3816152.1656503.90.44261.63036158.080.0110000.3213159.3657.9498.60.45941.61567164.170.0011720.2778165.7659.5493.80.47391.60318169.610.00111400.2448171.3660.8489.50.48671.592210179.040.00112620.1979181.3662.9481.60.50871.573912187.080.00113730.163189.864.5474.70.52731.558814194.130.00114760.1434197.3665.7468.40.54341.548516200.430.00114760.1434197.3665.7468.40.54341.548518206.150.00116630.1124210.2667.4457.20.57051.524320211.390.00117490.1015215.9668.0452.10.58221.515225222.910.00119530.1663198.8664.5474.70.52731.558830232.760.00121420.06794239.669.3429.70.62951.47835241.420.00123210.05817249.4669.3419.80.64851.464340249.180.00124940.05076258.4668.9410.50.66541.451445256.220.0012620.0449426.6668.3401.70.68061.439650262.690.00128260.04025274.3667.6393.30.69491.428860274.280.00121490.02798301.0665.5377.20.72031.409170284.470.00134690.02798301.0622.8361.80.74271.391580293.610.00137910.02406312.8659.7346.90.76311.3752100309.530.00144570.01848334.3652.3318.00.79931.3451120323.150.00151770.0146354.0634.5289.40.83161.3170140335.100.00159850.01183372.8632.8259.90.86161.2890160345.750.00169350.009615391.3619.7228.40.89051.2595180355.350.00181390.007794410.8603.7192.90.92051.2274200364.070.00199020.006187431.6582.8151.10.95201.1892220372.040.0023680.004423462.7545.883.10.99881.1276225.56374.150.003710.003170503.3503.301.06121.0612表7.7 末饱和水的比容和比焓 tum3/KgiKcal/kgum3/KgiKcal/kgum3/KgiKcal/kgP=1.0ataP=5.0ataP=10.0ata00.00100020.00.00100000.10.00099970.2200.001001720.10.001001520.10.001001320.2400.001007840.00.001007640.10.001016740.2600.001017160.00.001016960.10.001028760.0800.001029280.00.001029080.10.001028780.21000.0010435100.20.0010432100.21200.0010605120.40.0010602120.41400.0010800140.70.0010797140.81600.0011020161.4P=15.0ataP=20.0ataP=30.0ata00.00099950.30.00099930.50.00099880.7200.001001120.40.001000820.50.001000420.7400.001007240.30.001006940.40.001006540.6600.001016560.30.001016360.40.001015860.6800.001028580.30.001028380.40.001027880.51000.0010430100.30.0010427100.40.0010422100.61200.0010599120.50.0010596120.60.0010590120.81400.0010793140.90.0010790141.00.00120784141.11600.0011016161.40.0011012161.50.0011005161.71800.0011271182.30.0011267182.40.0011258182.52000.0011561203.60.0011551204.7表7.8 过热蒸汽表压力(Kg/cm3）(饱和温度）温 度 801001201401601802002202402601.0 v1.7291.8291.9272.0282.1202.2162.3112.4062.501(99.09） hs 638.9648.8658.4667.9667.4686.8696.3705.7715.21.75981.78551.80941.83191.85321.87361.89311.91191.93001.4 v1.3001.3711.4411.5101.5791.6481.7161.785(108.74） hs647.8657.6667.3676.9686.4695.9705.4714.9 1.74631.77081.79361.81521.83581.85551.87431.89251401601802002202402602803003202 v0.95391.0041.0531.1021.1511.1991.2471.2951.3421.390(119.62） h656.466.3676.1685.7695.3704.9714.5724.1733.7743.3 s1.72911.75261.77461.79541.81531.83431.85261.97031.88741.90393 v0.62940.66390.69760.73080.78370.79620.82860.86080.89280.9248(132.88） h656.4664.6674.7684.6694.3704.0713.7723.4733.1742.8s1.68021.70481.72751.74881.76911.78841.86091.82471.84191.85864 v0.49380.56190.54520.57020.59490.61940.64380.66800.6922(142.92） h662.9673.3683.4693.3730.2713.0722.8732.5742.3 s1.66991.69331.71521.73581.75541.77411.79211.80951.82625 v0.39160.41290.43370.45400.47410.49390.51360.53320.5526(151.11） h661.0671.8682.2692.3702.2712.2722.1731.9741.8 s1.64201.6621.68861.70961.72951.74851.76661.78411.80106 v0.32320.31460.35930.3760.39350.41030.42680.44320.4595(158.08） h659.2670.3680.9691.3701.4711.5721.4731.4741.3 s1.61841.64351.66651.68791.70811.72731.74561.76331.78027 v0.29070.30620.32120.33600.35050.36480.37900.3930(164.17） h688.7679.7690.2700.5710.7720.8730.8740.7 s1.62381.64741.66931.68981.70921.72771.74551.76268 v0.25240.26630.27970.29280.30560.31830.33080.3432(169.61） h664.1678.4689.1699.6709.9720.1730.1740.2 s1.60631.63051.65281.67371.69341.71211.73001.74729 v0.22260.23520.24740.25920.27020.28210.29330.3044(174.53） h655.5677.0688.0689.7709.1719.4729.5739.6 s1.59041.61531.63811.65931.67931.69811.71621.721210 v0.19870.21030.22150.23230.24280.25310.26330.7233(179.04） h663.8675.7686.9697.7708.3718.7728.9739.1 s1.57581.60151.62741.64631.6651.68561.70381.721216 v0.13390.14130.14180.15530.16200.1685(200.43） h679.7691.7703.2714.3725.1735.7 s1.56141.58541.67071.62771.64691.6651(饱和温度）220 24026028030032035040045050020 v0.10450.11080.11680.12260.12820.13360.13150.15430.16690.1792(211.38） h674.4687.4699.6711.2722.4733.4749.54755.9802.2828.1 s1.52831.55411.57741.5981.61871.63751.66401.70471.74221.777130 v0.069820.074500.078830.082920.086840.092490.10150.11010.1185(232.75） h675.3689.7702.9715.3727.2744.4722.0799.0825.7 s1.49061.51811.54241.56451.53491.61311.65571.69131.730140 v0.053010.056750.060170.063370.067910.074990.081200.08819(249.17） h678.4693.7707.6720.6739.0768.0795.8823.2 s1.46931.49751.52221.54451.57481.61951.65941.695950 v0.043290.046380.049210.053110.059080.061650.06998(262.70） h683.3699.2713.5733.4763.8792.6820.6 s1.45771.48591.51051.54321.59021.63151.6689100 v0.019880.023030.027050.030430.03348(309.53） h666.6699.5740.5775.3804.1 s1.36931.42351.48711.53681.5793150 v0.011990.016090.018890.02125(340.55） h647.5712.6755.8792.3 s1.30811.40921.47121.5200注:V为比容m3/Kg,h为比焓Kcal/kg,S为比热Kcal/Kgk。表7.9 水和蒸汽的导热系数102Kcal/(mh）tP Kgf/cm2饱 和 压 力12040水蒸汽048.849.049.248.91.512051.752.052.251.81.624054.254.454.654.21.736056.256.356.556.21.868057.557.757.857.51.991002.1058.658.858.52.131202.2459.159.358.92.301402.3859.259.359.12.481602.5358.959.058.82.691802.6958.258.458.12.432002.8557.257.354.13.222203.013.4255.955.73.672403.183.5054.154.14.002603.363.614.1851.94.542803.543.704.1851.94.543003.733.924.2546.46.183203.024.104.3743.37.553404.114.294.5239.69.723604.314.474.6934.512.93804.514.674.874004.714.875.064204.925.085.26表7.10 水和蒸汽的动力粘度系数U106KgfS/m2 tP Kgf/cm2饱 和 压 力12040水蒸汽0179179179178.90.8220102102102102.10.004066.466.466.466.40.986047.247.247.347.21.078035.835.835.935.81.151001.2328.528.528.51.231201.3223.523.523.51.301401.4019.920.919.91.381601.4817.317.317.21.151801.5715.215.315.21.522001.6513.713.713.61.592201.731.7012.412.41.662401.821.7811.411.41.742601.901.871.8410.52801.981.961.949.81.913002.062.062.059.22.023202.152.152.168.52.183402.232.242.267.62.433602.312.342.366.62.883802.402.422.454002.482.502.534202.562.582.61表7.11 水和蒸汽的物理性质准则Pr数 tP Kgf/cm2饱 和 压 力 12040水蒸汽013.012.912.813.00.85206.676.936.896.960.88404.324.304.294.320.01602.962.962.962.970.94802.202.202.192.200.961001.001.731.721.730.991201.001.421.421.431.921400.981.071.071.071.991600.981.071.071.071.991800.970.970.970.971.142000.970.900.900.911.202200.961.200.860.861