立式水蒸汽冷凝器 IMB standardization office【IMB 5AB- IMBK 08- IMB 2C】X X X X大学本科毕业论文题目:流量为130t/h立式蒸汽冷凝器专业:过程装备与控制工程班级:学生姓名:指导教师:论文提交日期:年月日论文答辩日期:年月日毕业设计(论文)任务书过程装备与控制工程专业班学生:摘要冷凝器它是使用范围很广的一种化工设备,属于换热器一种。
本设计任务主要是根据已知条件选择采用固定管板式换热器的设计,固定管板式换热器的优点是锻件使用少,造价低;传热面积比浮头式换热器大20%到30%且旁路渗流小。
本台换热器主要完成的是水蒸气-水之间的热量交换,首先根据给出的设计温度和设计压力来确定设备的结构形式以及壳程和管程的材料,然后根据物料性质和传热面积来确定换热管的材料,尺寸,根数。
,设计压力为管程,壳程,工作温度管程50℃,壳程130℃,设计温度管程80℃,壳程140℃,传热面积为256m2,采用Φ25××3000的无缝钢管换热,则可计算出622根换热管,D=1200mm的圆筒根据换热管的根数确定换热管的排列,并根据换热管的排列和长度来确定筒体直径以及折流板的选择。
通过对容器的内径和内外压的计算来确定壳体和封头的厚度并进行强度校核。
然后是对换热器各部件的零部件的强度设计,有法兰的选择和设计计算与校核,钩圈及浮头法兰的设计计算与校核和管子拉脱力的计算。
还包括管板的结构设计、防冲挡板、滑道结构的设计以及支座设计。
结构设计中的标准件可以参照国家标准根据设计条件直接选取;非标准件,设计完结构后必须进行相应的应力校核。
管板与换热管的连接方式为焊接,因管板上的应力较多,且内外温度有一定的差值,因此,对管板强度的校核是一个重点,也是一个难点.. 关键词:换热器;强度设计;结构设计AbstractThe condenser is a kind of chemical equipment which is widely used, and belongs to a kind of heat exchanger.. The design task is mainly according to the known conditions to choose the design of fixed tube plate heat exchanger, the advantages of fixed tube plate heat exchanger is forging used less, low cost; heat transfer area ratio of floating head type for heat exchanger is 20% to 30% and a bypass flow small.The heat exchanger is mainly completed is between water vapor and water heat exchange, first of all according to the given design temperature and pressure to determine structure of equipment and the shell side and tube side material, and then according to the nature of the material and the heat transfer area to determine the heat exchange tube materials, dimensions, number of roots. And design pressure for tube side , shell , the working temperature of the tube process 50 DEG C, 130 DEG C shell, design temperature tube process at a temperature of 80 DEG C, shell and 140 DEG C, heat transfer area for 256m2. The phi 25 x x 3000 seamless steel pipe heat exchanger can be calculated 622 heat exchange tube, D=1200mm cylindrical root according to determine the root number of heat exchange tube heat exchanger tube arrangement and according to the arrangement and length of heat exchange tube to determine cylinder diameter and baffle the choice. Determine the thickness of the shell and the head and carry out the intensity verification by calculating the inner diameter and the internal pressure of the container.. Then the strength design of components of the various components of the heat exchanger, flange design, selection and calculation and checking, hook and loop and floating head flange design calculation and checking of the pipe and pull off force calculation. Also includes a tube plate structure design, anti scour baffle, slideway structure design and the design of support. The standard parts in the structure design can be selected directly according to the national standards; the non standard parts must be checked for the corresponding stress after the design of the structure.Tube plate and tube heat exchanger and the connection mode of welding, tube plate more stress, and the temperature inside and outside have certain difference. Therefore, on the tube sheet strength check is a key and a difficulties.Keywords: heat exchanger; strength design; structure design目录第一章传统工艺计算工艺计算介质原始数据管程水的进口温度t1′=20℃管程水的出口温度t 1″=90℃ 管程水的工作压力MP P 1.21= 管程水的流量G 1=290t/h=290000kg/h 壳程水蒸气的入口温度t 2′=℃ 壳程水蒸气的出口温度t 2″=85℃ 壳程水蒸气的入口压力P 2=介质定性温度及物性参数①管程:管程水定性温度 1t =(1t '+ 1t '')/2=(20+90)/2=55℃ 管程水密度查物性表得1ρ= ㎏/m 3管程水比热查物性表得Cp 1=(Kg ﹒K ) 管程水导热系数查物性表得λ1=(m ﹒℃) 管程水粘度μ1=×10-4 Pa·s管程水普朗特数查物性表得 24.31=r P ②壳程:壳程水蒸汽定性温度: 壳程水蒸汽冷凝点 : t i = t 2′=℃冷却段:2t =(t i + t 2″)/2=(+85)/2=℃ 冷凝段:2t = (t 2′+ t i )=(+)/2=℃ 壳程水蒸汽密度查物性表得: 冷却段:ρ2=㎏/m 3冷凝段: p 2=㎏/ m 3壳程水蒸汽比热查物性表得: 冷却段:Cp 2= KJ/(Kg ﹒K ) 冷凝段:C p 2= KJ/(Kg ﹒K )壳程水蒸汽导热系数查物性表得: 冷却段:λ2 = W/(m ﹒K ) 冷凝段:λ2′= W/(m ﹒K ) 壳程水蒸汽粘度: 冷却段:μ2 =×10-6 Pa·s 冷凝段:u 2=×10-6 Pa·s壳程水蒸汽普朗特数查物性表得: 冷却段:Pr 2 = 冷凝段:P r 2=传热量与水蒸汽流量计算取定换热效率 =则设计传热量 :0Q = G 1×Cp 1×(t 1″- t 1′)×1000/3600=290000××(90-20)×1000/3600=×106W由0Q =2G [r+ Cp 2(t 2′- t 2″)]·导出水蒸气流量G 2,r 为t 2′时的汽化潜热,r=Kg 水蒸汽流量: G 2= Q 0//[r+ Cp 2(t i - t 2″)]=×106/[×1000+×1000×]=s冷却段传热量:Q 2=G 2·Cp 2·(t i - t 2″)=××103×=2481037W冷凝段传热量:Q 2= G 2设冷凝段和冷却段分界处的温度为3t根据热量衡算 : Q η2= 11p C G ⨯()13t t '- 3t =Q 2·/ G 1/ Cp 1+ t 1℃ 有效平均温差计算逆流冷却段平均温差: △t n =())t -t t -t ln()t -t (--t 123i 123i ''''''t =℃ 逆流冷凝段平均温差: △t n ′=()()⎪⎪⎭⎫ ⎝⎛-''-'--''-'312312ln t t t t t t t t i i =℃ 冷却段:参数:P=t3-ti -t3''t1=59.974-0.71759.974-90= 参数:R='-t3t1''t2'-ti =59.974-0958-0.717=换热器按单壳程 单管程设计则查图 2-6(a),得: 温差校正系数 = 有效平均温差: △t m =·△t n =×=℃ 冷凝段:参数:P='t1'-t2t1'-3t =02-0.71720-59.974= 参数:R=t1'-t3t2'-ti =20-59.9747.017-7.017=0换热器按单壳程 单管程设计则查图 2-6(a),得: 温差校正系数 =有效平均温差: △t m ′= ·△t n ′=×=℃管程换热系数计算初选冷却段传热系数:K 0′= 820 w/(m ·k) 初选冷凝段传热系数: K 0″= 1300 w/(m ·k)则初选冷却段传热面积为:F0=Q2·/( K0′·△tm)= 2481037×(820×= 初选冷凝段传热面积为: F0′=Q 选用25×的无缝钢管做换热管则: 管子外径d 0=25 mm 管子内径d i =20 mm 管子长度 L=3000 mm则需要换热管根数:N t =( F 0+ F 0′)/( πd 0L)=+/××3)= 可取换热管根数为 662根管程流通面积:a 1=t N ·π4d i 2= 662×π×40.022=管程流速: W 1 =1113600G a p = 290000/( 3600×× )= s管程雷诺数:Re 1=ρ1w 1d i /μ1=×××10-4)=则管程冷却段的定性温度:t 11=(t3+ t 1″)/2=+90)/2=℃ 管程冷却段传热系数:a 1′=3605×(1+ t 11) (100d i )^= 管程冷凝段的定性温度: t 12=(t3+t1′)/2=+20)/2=℃ 管程冷凝段传热系数: a 1″=3605×(1+ t 12) (100d i )^=管程结构初步设计查 GB151—1999知管间距按025.1d , 取管间距为:m S 032.0= 管束中心排管数为:Nc=Nt =,取30根 则壳体内径:D i =s (Nc-1)+4 d 0= 圆整为: 1200=i D 则长径比:i D L =1.23= 合理 折流板选择弓形折流板:弓形折流板的弓高:24.02.12.02.0=⨯==i D h折流板间距:B=3D i =31200=400㎜取B=400㎜ 折流板数量:N b =B L -1=0.43-1= 取7块壳程换热系数计算壳程流通面积: ⎝⎛⎪⎭⎫-=s d BD f i 021=××()=20.105m 壳程流速: 冷却段:w 2=222f p G =(×)=s 冷凝段:w 2=222f p G =(×)=s 壳程当量直径:de=(D i 2-N t d 02)/(N t d 0)=(21.2-711×20.025)/(711×)=① 冷凝段管外壁温度假定值: 6.109=w t ℃ 膜温:t m =(t w+ t 2′)/2=(+)/2=℃膜温下液膜的粘度:μm =195×10-6Pa·s膜温下液膜的密度:ρm =m3膜温下液膜的导热系数为:λm =(m ﹒℃)正三角形排列n s = N t =×662 =冷凝负荷:Γ=s2Ln G =(3×)= 壳程冷凝段雷诺数:Re =4Γ/u m =4×195×10-6=壳程冷凝段传热系数:a 2″=·(λm 3ρm g/μm 2)31(Re )31=② 冷却段管外壁温假定值:952=w t ℃ 冷却段雷诺数:Re=2e22u d w p =×××10-6= 壁温下水粘度:μw2=×10-6 Pa·s粘度修正系数:1=(w22u u )= 壳程传热因子查图 2-12 得: 100=s j 冷却段壳程换热系数:a 2′=(λ2/d e )·Pr 231 · 1 ·j s=()×31××100= 总传热系数计算查 GB-1999 第 138 页可知水蒸汽的侧污垢热阻:r 2=×10-5(m 2·℃/w )管程水选用地下水,污垢热阻为: ()W C m r o /1026251⋅⨯=- 由于管壁比较薄,所以管壁的热阻可以忽略不计 冷却段总传热系数:K j ′=1/[1/a 2′+r 2+r 1×d 0/d i +d 0/(a 1′×d i )]= 820传热面积比为: K j ′/ K 0′=(合理) 冷凝段总传热系数:K j 〞=1/[1/ a 2″+r 2+r 1×d 0/d i +d 0/(a 1″×d i )]= 传热面积比为: K j〞/ K 0〞=13001385.0607=(合理)管壁温度计算设定冷凝段的长度:m L 0424.2='' 冷却段的长度:m L 9576.0=' 冷却段管外壁热流密度计算:q 2′=Q 2/(N t πd 0 L′)=(m 2·℃)冷却段管外壁温度: t w ′=t 2-q 2′(1/a 2′+r 2)=℃误差校核:e′=t w2- t w ′==℃ 误差不大 冷凝段管外壁热流密度计算: q 2″=Q 2/( N t πd 0 L″)⨯)/ w/(⨯⨯⨯)=(m 2·℃) 冷凝段管外壁温度: t w ″=t m - q 2″(1/ a 2″+r 2)=℃误差校核:e = w t - t w ″=℃ 误差不大管程压力降计算管程水的流速: u 1=111a p 3600G =290000/(⨯⨯)=s管程雷诺准数:Re 1=ρ1w 1d i /μ1=⨯⨯(⨯-410)= 程摩擦系数:ξ==压降结垢校正系数:4.1=i d φ沿程压降:△P 1=ξρ1μ12Ldi /(2d i )=(⨯⨯20.393 1.43⨯⨯)/(20.02⨯)=取管程出入口接管内径:d 1′=250mm管程出入口流速:u 1′=4G/(3600πd 1′2ρ1)=(4⨯290000)/(3600 3.14⨯⨯20.25985.75⨯)=s局部压降: △P 3=ρ1 u 1′2(1+/2=(⨯21.67⨯)/2= Pa管程总压降: △P=△P 1+△P 3=+ = 管程允许压降:[]a P P 35000=∆ △P < [ △P] 即压降符合要求。