120t/h加热炉项目设计
目 录
1 设计依据 ........................................................................................................................ 1 2 燃料燃烧计算 ................................................................................................................ 1
2.1煤气干湿成分的换算 .......................................................................................... 1 2.2煤气低发热值 ...................................................................................................... 2 2.3煤气重度 .............................................................................................................. 2 2.4空气需要量 .......................................................................................................... 2 2.5燃烧产物生成量及成分 ...................................................................................... 3 2.6燃烧产物重度 ...................................................................................................... 4 3 炉膛热交换计算 ............................................................................................................ 4
3.1确定炉膛有关尺寸 .............................................................................................. 4 3.2求炉气黑度 .......................................................................................................... 5 3.3炉壁对金属的角度系数 ...................................................................................... 7 3.4求导来辐射系数C .............................................................................................. 7 4 金属加热计算 ................................................................................................................ 8
4.1金属均热段末（界面4）各有关参数 ............................................................... 8 4.2金属一加热段末（界面3）各有关参数 ........................................................... 9 4.3金属二加热段末（界面2）各有关参数 ......................................................... 11 4.4金属预热段末（界面1）各有关参数 ............................................................. 11 4.5金属预热段开始（界面0）各有关参数 ......................................................... 14 4.6各段平均热流及加热时间 ................................................................................ 14 5 确定炉子的主要尺寸 .................................................................................................. 15
5.1炉子有效长度 .................................................................................................... 15 5.2有效炉底强度 .................................................................................................... 16 6 炉子热平衡计算 .......................................................................................................... 17
6.1热收入项计算 .................................................................................................... 17 6.2热支出项计算 .................................................................................................... 18 7 换热器计算 .................................................................................................................. 30
7.1计算依据 ............................................................................................................ 30
7.2设计计算 ............................................................................................................ 31 .8 排烟系统流体力学计算 ............................................................................................. 36
8.1计算依据 ............................................................................................................ 36 8.2阻力计算 ............................................................................................................ 36 8.3烟囱计算 ............................................................................................................ 40 9 供风系统流体力学计算 .............................................................................................. 42
9.1.空气管道内径 .................................................................................................... 42 9.2.空气管道阻力损失 ............................................................................................ 43 10 炉底水管的校核 ........................................................................................................ 46 11 烧嘴计算 .................................................................................................................... 47 12 风机选择 .................................................................................................................... 49 13 选用装料机和出钢机 ................................................................................................ 50
3.13.1推钢机的选用 ............................................................................................... 50 3.13.2出钢机的选用 ............................................................................................... 50
参考文献 .................................................................................................................................. 57
项目设计
3.1 设计依据
1、炉子生产率：G=120t/h
2、加热钢种：普碳钢，钢坯尺寸：230mm×1600 mm×4000 mm的标准坯。 3、燃料：
(1)种类： 高焦炉混合煤气
(2)低发热量：2133×41.8=8916kJ/Nm3
4、加热参数：
(1)板坯加热初始温度t=20℃ (2)板坯加热终了温度t=1180 ℃ (3)板坯加热终了断面温差Δt≤30℃ (4)空气预热温度t=400 ℃ (5)出炉烟气温度t=900 ℃
3.2 燃料燃烧计算
按以上设计依据和设计方案进行如下热工计算。 高焦炉煤气的体积成分如表3.1。
表3.1 高焦炉煤气的体积成分（﹪）
干成分 体积 百分比
H2 30.96
N2 31.47
CH4 9.45
CO 14.49
CO2 12.46
C2H4 0.80
C2H6 0.33
C3H6 0.03
C3H8 0.01
3.2.1煤气干湿成分的换算 换算关系式[5]：
Xs?Xg100 (3.1)
100?0.124g式中：g─煤气含水量，g/m3；
Xs─湿煤气中各成分的体积，％；
Xg─干煤气中各成分的体积，％； 已知高焦炉混合煤气温度为20℃，g=18.9g/Nm3。
Xs?Xg100?0.977Xg
100?0.124?18.9求得高焦炉混合煤气成分列入表3.2中。
表3.2 高焦炉混合煤气中各种成分体积 （﹪）
高焦炉混合煤气 H2 N2 CH4 CO CO2 0.977×30.96﹪=30.25﹪ 0.977×31.47﹪=30.55﹪ 0.977×9.45﹪=9.23﹪ 0.977×14.49﹪=14.56﹪ 0.977×12.46﹪=11.98﹪ C2H4 C2H6 C3H6 C3H8 H2O 0.977×0.80﹪=0.78﹪ 0.977×0.33﹪=0.32﹪ 0.977×0.03﹪=0.03﹪ 0.977×0.01﹪=0.01﹪ 0.977×18.9﹪×0.124=2.29﹪ 3.2.2煤气低发热值 计算公式：
Qd=30.2CO+25.8H2+85.6CH4+142.9C2H4+152C2H6+207.7C3H6+218C3H8 (3.2) =30.2×14.56+25.8×30.25+85.6×9.23+142.9×0.78+152×0.32+207.7×0.03+218×0.01 =2130kcal/Nm3
=8916kJ/Nm3 3.2.3煤气重度
1(2×H2+28×N2+16×CH4+28×CO+44×CO2+28×C2H4+30×C2H6
22.4?100r0煤=
+42×C3H6+44×C3H8+18×H2O) =
1(2×30.25+28×30.55+16×9.23+28×14.56+44×11.98+28×0.78+30×0.32
22.4?100+42×0.03+44×0.01+18×2.29) =0.93kg/Nm3 3.2.4空气需要量 (1)理论空气需要量 L0=
1??×?0.5CO?0.5H2?3CH4???m?21???n?CHn?1.5HS?O?m22? (3.3)4??