P-短窑设计特点.pdf

PYRORAPID design 1 Design Characteristics of the PYRORAPID Short Rotary Kiln PYRORAPID 两支撑短窑的设计特点 Abstract 摘要 The benefits offered by the short kiln from the point of view of the designer are outlined by comparing a standard preheater kiln PYROCLON R with a PYRORAPID short rotary kiln each designed for a production capacity of 2800t d 笔者通过生产能力均为日产 2800 吨的普通预热器 PYROCLON R 窑和 PYRORAPID 短窑进 行比较 阐述短窑的一些特点 The major advantage of the short rotary kiln is that it is a statically defined system This means that overload conditions which may occur for standard kilns carried on three roller stations e g as a result of foundation subsiding and or kiln tube warping are eliminated for short rotary kilns Therefore when dimensioning kilns with reference to identical maximum admissible specific loads the short kiln features markedly greater safety margins with respect to wear and fracture 短窑的主要特点是静态组合系统 也就是说普通三支撑窑可能发生基础沉降和 或窑筒体弯曲 造成的过负荷情况 短窑完全不会出现 因此 从窑最大单位荷载方面 短窑抗磨损和破裂的 安全系数明显增大 The conclusive results obtained when comparing pier loadings speeds drivers weights and design details round off the overall positive outcome in favour of the short rotary kiln PYRORAPID 通过对窑墩荷载 窑速 窑传动 窑重量及其设计方面的全面比较 短窑 PYRORAPID 确实 有许多优点 现介绍如下 1 Introduction 简介 Formerly long rotary kilns operated by the wet or dry process and were equipped with 6 roller station or more and as general practice for the manufacture of cement 较早水泥湿法和或干法长窑一般带有 6 组托轮或更多 Since the introduction of cyclone preheaters the kiln with three roller stations has taken a leading position The kiln length diameter ratio of current standard preheater kilns equals ratio of current standard preheater kilns equals about 14 to 1 自从采用悬浮预热器窑后 三支撑窑占据了主要地位 目前大多数悬浮预热器窑的长径比为 14 比 1 With the kiln dimensions remaining unchanged the kiln throughput has been more than doubled since interaction of the precalcining process PYROCLON R The length diameter ratio was also not changed 即使后来采用同样规格窑型 产量成倍增长的窑外分解 PYROCLON R 工艺后 窑的长径比 也没有改变 PYRORAPID design 2 The use of a short kiln became feasible only with the introduction of the PYRORAPID method While the kiln diameter remains unchanged for identical throughput the kiln length equals no more than the eleventh of this nominal diameter That short kiln is equipped with only 2 roller stations 短窑的在采用 PYRORAPID 之后才切实可行 但窑的直径在产量同样的情况下没有改变 长 度为名义直径的 11 倍 因此 该种长径比的窑只使用两支撑结构 Setting the two kiln systems Fig 1 and the arrangement of their zones side by side indicates that inside the short kiln virtually almost nothing but the clinkering process takes place The temperature at the kiln inlet is slightly higher for the short kiln The resulting structural measures will be outlined at the end of this paper 将两种窑 图 1 的各功能部位一一进行对比 几乎没有什么变化 只是分解带发生了较大变 化 短窑窑尾温度略有增加 因此 窑尾密封结构相应进行改进 改变情况在本文结尾将简单 介绍 The following statements compare from a designer s viewpoint the standard PYROCLON R kiln carried on 3 roller stations with the PYRORAPID kiln on 2 roller stations This paper will concentrate solely on aspects that clearly differ for the two versions 本文从设计角度对普通三支撑 PYROCLON R 窑与两支撑 PYRORAPID 进行对比分析 All parameters included in the comparison have been determined for kilns of 2800t d clinker capacity The standard kiln measures 4 2m in diameter and 57m in length and the short kiln same diameter and 46m in length fig 2 NORMAL KILN PYROCLON 普通三支撑窑 R 14Xdia SHORT KILN PYRORAPID 两支撑短窑 11Xdia R caicining zone 分解带 transition zone 过渡带 sintering zone 烧成带 outlet zone 冷却带 Fig 1 Comparision of standard and short kiln showing zone 图1 标准窑和短窑各功能带的对比 PYRORAPID design 3 Kiln production 窑产量 2800t d Normal kiln 普通三支撑窑 Short kiln 两支撑短窑 PYROCLON RPYRORAPID 4 2 57m4 2 46m Fig 2 Example of rotary kiln comparison 图 2 两种窑型实例对比 所有窑参数的对比都是在日产 2800 吨熟料基础上进行 普通三支撑窑直径为 4 2 米 长度为57 米 短窑直径与普通三支撑一样 长度为 46 米 图 2 2 Rotary kiln statics 回转窑的荷载分析 The structure analysis of rotary kiln considers all rotary masses and the kiln filling feed material and coatings as liners as well as point loads 在结构荷载分析时 所有与窑一同运动的窑 内填充物 喂料和窑皮 以及窑内的耐火材 料均予以考虑 A technical kiln designer formerly had to do that analysis by painstaking and time consuming calculations in accordance with Clapeyron s equation Varying moments of inertia could be accounted for only by way of factors These calculations became particularly elaborate as soon as subsiding of supports or temperature differences had to be taken into account 以前窑的设计者在对窑进行设计计算时采用 Clapeyron 计算法即费时又费力 许多荷载变量无 法计算 只有采用系数法处理 这些计算还受到基础沉降或温度变化引起的热膨胀而影响准确 度 Today that analysis is carried out at maximum accuracy with the aid of most up to date processing programs on large computer systems duly considering all influencing parameters The time needed for the calculations is no more than seconds and for the printout a few minutes only The printouts indicate bending moments shearing forces stress distribution elastic line etc 现在进行类似的计算均采用计算机极其相应的专门程序来进行精确计算 在计算中还可以考虑 各种影响因素 计算过程只需要很短时间 计算结果打印也无需太多时间 计算结果包括如弯 曲力 剪切力 应力分布和弹力线等 The standard kiln carried on 3 roller stations is a statically indefinite system 普通三支撑窑是一个不确定的静态受力系统 The conditional equations of structural analyses do not suffice for determining the load distribution onto the roller stations Instead the elastic deformations of the kiln tube have to be referred to Fig 3 shows the typical elastic line of a kiln with 3 roller stations indicating a maximum deflection of approx 2mm at kiln inlet 在对托轮负荷分布的结构分析时 各种不同前提条件很难同时满足 图 3 所示的典型普通三支 撑窑筒体弹性变形造成在窑尾至少约 2mm 的偏差 The upper left load condition in Fig 4 displays the standard load distribution 图 4 左上所显示的是正常情况下的荷载分布 A deformed kiln axle caused for instance by the settlement of foundations or warping of the kiln shell will induce a changed load distribution A number of typical load conditions which may certainly occur in practice reveal that the roller station loads may rise to more than twice the standard PYRORAPID design 4 2910KN 3139KN 2514KN Normal kiln 普通三支撑窑 Short kiln 两支撑短窑 3850KN 3810KN Inlet 窑尾 Outlet 窑头 Inlet 窑尾 2615KN 295KN 10 1 3799KN 660KN 21 0 2150KN 364KN 14 5 failure condition 1 第一种荷载分布变化情况 5mm 5mm 4314KN 1404KN 48 2 4250KN 1736KN 69 0 failure condition 2 第二种荷载分布变化情况 1000KN 1910KN 65 6 7525KN 4425KN 141 0 failure condition 3 第三种荷载分布变化情况 Fig 4 Loading cases of normal kiln and standard load case of short kiln 图4 不同情况下普通三支撑窑荷载分布以及两支撑短窑荷载分布情况 Outlet 窑头 05101535302520454050556065 m 2 50 2 00 1 50 1 00 0 50 0 00 0 50 mm Inlet 窑尾Outlet 窑头 Fig 3 Deflection of normal kiln at normal condition 图3 普通三支撑窑正常情况下的变形 PYRORAPID design 5 level Fig 4 refers lower load conditions Obviously the loads exerted on the different structural components will increase accordingly 例如由于基础沉降或筒体变形将会导致各点荷载分布产生变化 这种情况实际上肯定也会发 生 图 4 中所示几种荷载分布变化中 第三种情况会导致中间托轮组比正常荷载高出一倍多 所以 在结构设计上不得不考虑这种情况的荷载变化 Relieving of a specific roller station will always result in correspondingly higher load acting on the adjacent station or stations That effect will grow with the kiln tube stiffness and be reduced for weaker more elastic softer kiln tubes 针对这种可能发生的荷载变化 习惯办法是始终相应提高该处及相临托轮组的承载能力 同时 提高窑筒体整体刚度 降低筒体变形和弹性 A kiln is considered stiff if the distance of the roller stations is narrow and its shell plates are relatively thicker In contrast to this a soft kiln is characterized by wider roller station distances and relatively thin shell plates 如果两组托轮距离较小 应考虑相应提高筒体刚度 筒体厚度适当加厚 而针对托轮组之间距 离较远的筒体部分应降低筒体刚度 筒体厚度适当减薄 Standard preheater kilns with 3 roller stations have fairly short roller station distance because of their length diameter ratio There fore these kilns are stiff The diagram reveals that foundation subsiding and deformation of the kiln axle have significant effects on kiln statics 三支撑的普通预热器窑由于长径比和托轮组的数量关系 托轮组之间的距离相对较近 所以 这种类型的窑筒体刚性较高 从荷载分布图可以看出基础的下沉和筒体轴向变形对窑的荷载有 很大的影响 Although the permissible specific loads are kept low upon kiln dimensioning operating a kiln with 3 roller stations will have to make absolutely sure that damage caused by overload is avoided But this can be done by modern computer aided monitoring and gauging devices 虽然从窑的尺寸和结构来讲 这种荷载完全可以承受 而且目前三支撑窑在运行中可以通过现 代化计算机辅助监测系统和仪器仪表进行监测 不会出现因过负荷而造成损坏 The situation is completely different for the short kiln This system with 2 roller stations is a statically defined system 短窑的情况就完全不同了 该两支撑系统是一个相对静态载荷系统 In the event of the above influences i e foundation settlement and kiln tube warping there can be no interaction between the roller station loads There is nothing else than the normal load condition as shown in fig 4 on the upper right side 从图 4 右上显示可以看出基础沉降和窑筒体变形不会影响托轮组的正常荷载 It this for the reasons just mentioned that the specific loads exerted on the different components do not undergo any changes either This becomes obvious when studying the reference stress curves fig 5 This effective stress is used as reference value for determining the plate thickness of a kiln tube 从图 5 的筒体断面压力曲线可以看出不同部分和不同状态下的荷载分布 这些荷载分布可以作 PYRORAPID design 6 为窑筒体钢板厚度选择的依据 Whereas the reference stress may under the failure load condition 2 increase to four times the standard value for the kiln of standard length that stress does not change for short kiln 普通三支撑窑在第二种荷载分布情况时 筒体承载压力高出正常状态 4 倍 而两支撑短窑不变 When dimensioning kilns with reference to identical specific loads under normal operation conditions it become obvious that the short kiln features distinctly greater safety margins operation than a kiln of standard because overload contingencies of purely static kind simply do not exist 当设计窑时必须考虑窑在各种情况运行时的荷载变化 短窑在安全系数上不需要考虑普通三支 撑窑过负荷引起的荷载变化 3 Pier loadings 窑墩荷载 The survey fig 6 indicates standard pier loadings 图 6 中显示为正常情况下窑墩的荷载 Considering the sum of the three pier loadings of a standard kiln to be 100 the sum of the two pier loadings of short kiln equals no more than 86 5 0 15 10 40 20 80 50 45 60 55 65 70 75 85 90 25 30 35 5 0 15 10 20 25 05101520302535604045505503510515202530504045 N mm2Inlet窑尾Outlet窑头 Inlet 窑尾N mm2Outlet窑头 Failure conditions 2 荷载状态2 Normal conditions 1 荷载状态1 4 2X46m Short kiln 两支撑短窑 4 2X57m Normal kiln 普通三支撑窑 Fig 5 Reference stress 图 5 筒体断面压力 PYRORAPID design 7 如果考虑将普通三支撑窑的三个窑墩总荷载认定为 100 那么两支撑短窑两个窑墩的总荷载 为 86 The individual pier loading of the standard kiln result in bearing of size DGL 450 at inlet and in the middle DGL 400 at the outlet This means that the most cost effective version includes two different bearing sizes Providing identical size for all bearings for reasons of inventory streamlining means higher prices 三支撑窑各窑墩的荷载不同导致选用不同的轴承 DGL 450 用于窑尾和中档托轮轴上 DGL 400 用于窑头托轮轴上 这意味着采用两种规格托轮轴将会提高制造和维护成本 如果全部采用一样的轴承 同样会造 成采购成本增加 Contrary to that the short kiln has two roller stations of identical size equipped with bearing DGL 500 两支撑短窑由于结构关系与三支撑窑不同 只采用一种托轮轴 DGL 500 Fixing most appropriate tire distance allows to keep the difference between the pier loadings small 选择和定位托轮组之间的合适距离 并允许两组托轮荷载有较小的差别 4 Downhill thrust of the kiln 窑的推力挡轮 The downhill thrust of the two kilns is at identical slope directly proportional to the sum of their pier loadings fig 7 两种窑在一定斜度情况下对窑墩的产生的荷载如图 7 所示 This force acting on the thrust rollers equals 300kN for the standard kiln and Normal kiln 普通三支撑窑Short kiln 两支短撑窑 DGL 450DGL 450DGL 400 Inlet 窑尾Outlet 窑头Inlet 窑尾Outlet 窑头 Large bearings 轴瓦 Pier loadings 窑墩荷载 2910KN3139KN2514KN DGL 500DGL 500 3850KN3510KN Pier loadings 窑墩荷载合计 8563KN 100 7360KN86 Fig 6 Pier Loadings 图6 窑墩荷载 PYRORAPID design 8 258kN for the short kiln which is 14 less 该荷载作用在推力挡轮上的力分别为 普通三支撑窑 300kN 两支撑短窑 258kN 比普通三支撑窑小 14 The resulting size of the hydraulic thrust roller bracket to be installed is type HDR 50 for the standard kiln and type HDR 30 for the short kiln i e the next smaller size 相应的液压推力挡轮为 普通三支撑窑 HDR 50 两支撑短窑 HDR 30 就是采用较小的挡轮 Obviously the force to be generated for hydraulic longitudinal movement of the short kiln is correspondingly less 很明显 两支撑短窑作用于液压推力挡轮的水平作用力要相对低一些 5 Kiln speed and drive powers 窑速和驱动功率 Kiln inclination and speed determine the residence time of the material inside the kiln 回转窑的斜度和转速是窑内物料滞留时间的主要影响因素 While the slope of the two kilns is identical i e 3 5 their speed differs slightly as it shown in fig 8 The short kiln revolves approx 10 more slowly and its theoretical filling is therefore somewhat greater 两种窑型的斜度是一样的 即 3 5 窑速如图 8 所示略有不同 两支撑短窑的转速比普通三 支撑窑低约 10 且窑内理论填充率略高 The calculated driving power of the standard kiln amount to 200kW that of the short kiln to 185kW This means a saving of 0 13kWh per t of clinker produced for the short kiln 普通三支撑窑的计算驱动功率为 200kW 短窑为 185kW 这意味着短窑生产每吨熟料比普通 Inlet 窑尾 Normal kiln 普通三支撑窑 Outlet 窑头Outlet 窑头 Short kiln 两支短撑窑 Inlet 窑尾 HDR 50HDR 30Thrust roller type 推力托轮型号 300KN258KN 100 86 Fig 7 Downhill thrust 图7 推力挡轮 PYRORAPID design 9 三支撑窑降低电耗 10 3kWh The ratio of the install motor powers corresponds to the actual driving power 装机功率要根据实际情况确定 Normal kiln 普通三支撑窑 Dia 4 2 57 0m Short kiln 两支撑短窑 Dia 4 2 46 0m Difference 比较 Speeds required 转速要求 2 80 min 12 50 min 10 30 min 1 Maximum speeds 最高转速 3 30 min 13 00 min 10 30 min 1 Power required 需用功率 200 kW185 kW15 kW Motor required 装机功率 430 kW390 kW40 kW Fig 8 Kiln speed and power requirements 图 8 窑转速和功率 Structure components 窑主要部件 Normal kiln 普通三支撑窑 Dia 4 2 57 0m Short kiln 两支撑短窑 Dia 4 2 46 0m Difference 比较 Kiln tube compl 窑筒体 178 0t149 0t29 0t Tyres incl fastenings 轮带极其固定件 85 0t66 0t19 0t Ro