列管式換熱器的工藝設(shè)計(jì)及選用

..化工原理課程設(shè)計(jì)說明書題目：列管式換熱器的工藝設(shè)計(jì)和選用課程名稱：化工原理課程設(shè)計(jì)設(shè)計(jì)人：吳琳瑜專業(yè)：化學(xué)工程與工藝班級(jí)：化工B081學(xué)號(hào)：200801034119指導(dǎo)老師：李辰明學(xué)校：華北科技學(xué)院目錄設(shè)計(jì)條件····················································································3設(shè)計(jì)題目·····················································································3設(shè)計(jì)任務(wù)····················································································3設(shè)計(jì)原則··················································································3設(shè)計(jì)流程·····················································································3一、確定設(shè)計(jì)方案·········································································31.選擇換熱器類型······································································32.確定冷、熱流體流徑途徑··························································4二、流體有關(guān)物性數(shù)據(jù)···································································4三、估算傳熱面積·········································································41.計(jì)算熱負(fù)荷············································································42.冷卻水用量·············································································43.傳熱平均傳溫差·······································································4四、初算傳熱面積·········································································4五、工藝結(jié)構(gòu)尺寸·········································································51.選管子規(guī)格·············································································52.總管數(shù)和管程數(shù)······································································53.初選換熱器類型與型號(hào)·····························································54.確定管子在管板上的排列方式TC"傳熱管排列和分程方法"\fC··················································55．管子與管板、管板與殼體的連接···············································66.殼體內(nèi)徑的確定·····································································67.確定實(shí)際管子數(shù)目··································································68.折流擋板··············································································69.其他附件··············································································710.接管···················································································7六、換熱器核算··········································································81.總傳熱系數(shù)K的計(jì)算·····························································8=1\*GB2⑴管內(nèi)傳熱膜系數(shù)··································································8=2\*GB2⑵管外傳熱膜系數(shù)·································································8=3\*GB2⑶污垢熱阻和管壁熱阻····························································9=4\*GB2⑷總傳熱系數(shù)K······································································9=5\*GB2⑸傳熱面積校核·····································································92.壁溫的計(jì)算··········································································93.核算壓力降···········································································10=1\*GB2⑴管程壓力降········································································10=2\*GB2⑵殼程壓力降········································································10七、設(shè)計(jì)計(jì)算結(jié)果匯總表·····························································11八、總結(jié)·····················································································12參考文獻(xiàn)·····················································································13CAD圖紙····················································································14設(shè)計(jì)題目：列管式換熱器的工藝設(shè)計(jì)和選用設(shè)計(jì)條件煉油廠用原油將柴油從175℃冷卻到130℃。柴油流量為12500kg/h原油初溫為70℃,經(jīng)換熱后升溫到110℃。換熱器的熱損失可忽。管、殼程阻力壓降不大于30kpa。污垢熱阻均取0.0003m2·℃·W-1。試設(shè)計(jì)一臺(tái)列管式換熱器,完成該生產(chǎn)任務(wù)。設(shè)計(jì)任務(wù)根據(jù)設(shè)計(jì)條件選擇合適的換熱器型號(hào),并核算換熱面積,壓力降是否滿要求,并設(shè)計(jì)管道與殼體的連接,管板與殼體的連接,折流板數(shù)目、形式等。繪制列管式換熱器的裝配圖。編寫課程設(shè)計(jì)說明書。設(shè)計(jì)原則1.滿足工藝和操作要求設(shè)計(jì)出來的流程和設(shè)備首先要保證質(zhì)量,操作穩(wěn)定,這就必須配置必要的閥門和計(jì)量?jī)x表等,并自確定方案時(shí),考慮到各種流體的流程,溫度和壓強(qiáng)變化使采取什么措施來調(diào)節(jié),而在設(shè)備發(fā)生故障時(shí),加修應(yīng)方便。2.滿足經(jīng)濟(jì)上的要求在確定某些操作指標(biāo)和治標(biāo)和選定設(shè)備型式以及儀表配置時(shí),要有經(jīng)濟(jì)核算的觀點(diǎn),既能滿足工藝和操作要求,又使施工簡(jiǎn)便,材料來源容易,造價(jià)低廉。如果有廢熱可以利用,要盡量節(jié)省熱能,充分利用,或者采取適當(dāng)?shù)拇胧┻_(dá)到降低成本的目的。3.保證安全生產(chǎn)在工藝流程和操作中若有爆炸、燃燒、中毒、燙傷等危險(xiǎn),就要考慮必要的安全措施。又如設(shè)備的材料強(qiáng)度的演算,除按規(guī)定應(yīng)有一定的安全系數(shù)外,還應(yīng)考慮防止由于設(shè)備中壓力突然升高或者造成真空而需要裝置安全閥等,以上提到的都是為了保證安全生產(chǎn)所需要的。設(shè)計(jì)方案也可能一次定不好,后來需要修改,但各物料流通路線和操作指標(biāo)的改動(dòng)都對(duì)后面的計(jì)算的影響,所以最好第一次確立就考慮周到些。設(shè)計(jì)流程一、確定設(shè)計(jì)方案1.選擇換熱器類型兩流體的溫度變化情況：熱流體進(jìn)口溫度為175℃,出口溫度為130℃。冷流體進(jìn)口溫度為70℃,出口溫度為110℃由于冷、熱流體溫差較大,同時(shí)為了便于拆卸清洗,選用浮頭式列管換熱器。2.確定冷、熱流體流徑途徑由于柴油較易結(jié)垢,為便于清洗,應(yīng)使柴油走管程,原油的粘度大,在裝有折流擋板的殼程中流動(dòng)。有利于提高湍動(dòng),增大傳熱系數(shù),原油走殼程。二、流體有關(guān)物性數(shù)據(jù)物料kg/m3kJ/<kg℃>W·m-1·℃-1Pa·s原油8150.128柴油7150.133三、估算傳熱面積1.計(jì)算熱負(fù)荷〔忽略熱損失W2.冷卻水用量<忽略熱損失>kg/s3.傳熱平均傳溫差先按逆流計(jì)算=溫度校正：R＝＝＝0.38P＝＝＝1.13據(jù)R、P值,查溫差校正系數(shù)圖,得溫度校正系數(shù)=×=0.92×62.5=57.50℃四、初算傳熱面積參照傳熱系數(shù)K的大致范圍,取=230W/<m2·℃>,則估算面積為：＝=取實(shí)際面積為估算面積的1.1倍,則實(shí)際估算面積為：A=1.1=1.1×29.30=32.23m2五、工藝結(jié)構(gòu)尺寸1.選管子規(guī)格選用252.5mm的無縫鋼管,管長(zhǎng)L=6m。2.總管數(shù)和管程數(shù)總管數(shù)根單程流速=單程流速較低,為提高傳熱效果考慮采用多管程。按管程流速的推薦范圍,選管程流速為=1m/s,所以管程數(shù)為=取4管程3.初選換熱器類型與型號(hào)由于冷、熱流體溫差較大,同時(shí)為了便于拆卸清洗,選用浮頭式列管換熱器為宜,=2\*ROMANII=2\*ROMANII的具體參數(shù)殼徑/mm400管子尺寸25mm×2.5mm公稱壓力/MPa1.00管長(zhǎng)/m6計(jì)算換熱面積/m31.6管子總數(shù)68管程數(shù)4管子排列方式四邊形錯(cuò)列殼程數(shù)1折流擋板形式弓形4.確定管子在管板上的排列方式TC"傳熱管排列和分程方法"\fC管子布置應(yīng)在換熱器的截面上均勻而緊湊的分布,此外還有考慮流體的性質(zhì)和結(jié)構(gòu)設(shè)計(jì)及制造等方面的問題管子的排列方式有等邊三角形和正方形兩種。如圖〔a、圖〔b所示。與正方形相比,等邊三角形排列比較緊湊,管外流體湍動(dòng)稱帝高、表面?zhèn)鳠嵯禂?shù)大。正方形排列雖比較松散,傳熱效果也較差,但管外清洗方便,對(duì)易結(jié)垢流體更為適用。如將正方形排列的管束轉(zhuǎn)45度安裝如圖〔c可在一定的程度上提高對(duì)流傳熱系數(shù),采用正方形錯(cuò)列。5．管子與管板、管板與殼體的連接=1\*GB2⑴在管殼式換熱器的結(jié)構(gòu)設(shè)計(jì)中,管子與管板的連接是否緊密十分中。如果連接不緊密,在操作時(shí)連接處發(fā)生泄漏,冷熱流體互相混合,會(huì)造成物料和熱量損失；若物料帶有腐蝕性、放射性或者兩種流體接觸會(huì)產(chǎn)生易燃易爆物質(zhì),后果將更加嚴(yán)重。在固定管板式換熱器的連接方法處還應(yīng)考慮能承受一定的軸向力,以避免溫度變化較大時(shí),產(chǎn)生的熱應(yīng)力使管子從管板脫出。焊接法由于具有很多的優(yōu)點(diǎn)〔加工簡(jiǎn)單、對(duì)管空的加工要求不高,較強(qiáng)的抗脫能力使之在高溫高壓下仍能保持連接處的緊密性,同時(shí)在壓力不太高時(shí)還可采用薄型管板,在一些要求較高的場(chǎng)合被廣泛應(yīng)用。管子與管板采用焊接結(jié)構(gòu)。=2\*GB2⑵浮頭式換熱器通常是把管板夾在殼體法蘭與管箱法蘭之間便于管殼程一起清洗。管心距取a=1.25d0=1.25×25=31.25≈32mm隔板兩側(cè)相鄰管心距6.殼體內(nèi)徑的確定取管板利用率η=0.8,則殼體內(nèi)徑為：按殼體標(biāo)準(zhǔn)圓整取7.確定實(shí)際管子數(shù)目N=688.折流擋板換熱器內(nèi)安裝折流擋板是為了提高殼程流體的對(duì)流傳熱系數(shù)。為了獲得良好效果,折流擋板的尺寸和間距必須適當(dāng)。對(duì)于常用的圓缺形擋板,弓形切口太大或太小,都會(huì)產(chǎn)生流動(dòng)"死區(qū)",如圖所示,不利于傳熱,且增加流體阻力。一般切口高度與直徑之比為0.15-0.45,常見的有0.20和0.25兩種。擋板的間距對(duì)殼程的流動(dòng)有重要的影響,間距太大不能保證流體垂直流過管束,使得管外給熱系數(shù)降低,間距太小又不方便檢修,阻力損失也很大。一般采用間距為殼體的0.2-1.0倍。取板間距B＝200mm。而對(duì)圓缺形擋板而言,弓形缺口的大小對(duì)殼程流體的流動(dòng)情況有中重要的影響。弓形缺口太大還是太小都有可能造成流體"死區(qū)",既不利于傳熱也不利于流體的流動(dòng)。一般來說,弓形口的高度可取殼程的0.1-0.4。據(jù)以上原理可以選擇的缺口高度以及擋板常采用0.2和0.25采用弓形折流板。折流板數(shù)=－1=－1=29<塊>9.其他附件=1\*GB2⑴拉桿選拉桿直徑為16mm,拉桿數(shù)量為4根。=2\*GB2⑵封頭封頭有方形和圓形兩種,方形用于小直徑〔<400mm的殼體圓形用于較大直徑的殼體。=3\*GB2⑶緩沖擋板為防止殼程流體進(jìn)入換熱器時(shí)對(duì)管束的沖擊,可在進(jìn)料口裝設(shè)緩沖擋板。=4\*GB2⑷導(dǎo)流桶殼程流體的進(jìn)、出口和管板間必存在有一段流體不能流動(dòng)的空間〔死角,為了提高傳熱效果,常在管束外增設(shè)導(dǎo)流桶,使流體進(jìn)、出殼程時(shí)必然經(jīng)過這個(gè)空間=5\*GB2⑸放氣孔、排液孔換熱器的殼體上常安有放氣孔和排液孔,以排除不凝氣體和冷凝液等。10.接管=1\*GB2⑴管程流體進(jìn)出口接管。取管內(nèi)流速則接管內(nèi)徑按管子標(biāo)準(zhǔn)圓整,取管程流體進(jìn)出口接管規(guī)格為無縫鋼管。=2\*GB2⑵殼程流體進(jìn)出口接管。取管內(nèi)流速則接管內(nèi)徑按管子標(biāo)準(zhǔn)圓整,取殼程流體進(jìn)出口接管規(guī)格為無縫鋼管。六、換熱器核算1.總傳熱系數(shù)K的計(jì)算=1\*GB2⑴管內(nèi)傳熱膜系數(shù)由計(jì)算。流體被加熱,取n=0.4管程流體流速==2\*GB2⑵管外傳熱膜系數(shù)由計(jì)算。傳熱當(dāng)量直徑=殼程流通截面積m殼程流體流速殼程中柴油被冷卻,取0.95W/<m2·℃>=3\*GB2⑶污垢熱阻和管壁熱阻管內(nèi)、外側(cè)的熱阻均取。已知管壁厚；取碳鋼導(dǎo)熱系數(shù)。=4\*GB2⑷總傳熱系數(shù)K總傳熱系數(shù)K為：=5\*GB2⑸傳熱面積校核所需傳熱面積前已算出換熱器的實(shí)際傳熱面積,則：說明該換熱器有17.7%的面積裕度,在10%～25%。滿足此要求,能完成生產(chǎn)任務(wù)。2.壁溫的計(jì)算換熱管壁溫可由下式估算已知：；；換熱管平均壁溫為殼體壁溫可近似取為殼程流體的平均溫度,即,。殼體壁溫與傳熱管壁壁溫之差為該溫差小于50℃,故不需設(shè)置溫差補(bǔ)償裝置。3.核算壓力降=1\*GB2⑴管程壓力降已知。對(duì)于碳鋼管,取管壁粗糙度由關(guān)系圖中查得=2\*GB2⑵殼程壓力降已知;,有管子按正方形錯(cuò)列,折流擋板間距折流擋板數(shù)殼程流通截面積殼程流速所以計(jì)算結(jié)果表明,管程和殼程的壓力降均能滿足設(shè)計(jì)要求。三、設(shè)計(jì)計(jì)算結(jié)果匯總表換熱器的工藝計(jì)算及結(jié)構(gòu)設(shè)計(jì)的主要結(jié)果和主要尺寸匯總于下表：工藝參數(shù)管程殼程質(zhì)量流量/<kg/h>1250015840進(jìn)/出口溫度/℃175/13070/110物性參數(shù)定性溫度/℃152.590密度/<kg/m3>715815定壓比熱熔/[kJ/<kg·K>]2.482.2粘度/<Pa·s>0.64×10-53×10-3熱導(dǎo)率/[W/<m·K>]0.1330.128工藝主要計(jì)算結(jié)果流速/<m/s>0.910污垢熱阻/[m2·K/W]0.00030.0003阻力〔壓降/kPa19.892.049對(duì)流傳熱系數(shù)/[W/<m2·K>]1500422.4總傳熱系數(shù)K/[W/<m2·K>]250平均傳熱溫差/℃57.50熱流量/kW387.5傳熱面積裕度/%17.7設(shè)備結(jié)構(gòu)設(shè)計(jì)程數(shù)41推薦使用材料碳鋼碳鋼換熱器型式浮頭式換熱器臺(tái)數(shù)1殼體內(nèi)徑/mm400傳熱面積/m231.6管徑/mmФ25×2.5折流板型式上下管數(shù)/根68折流板數(shù)/個(gè)29管長(zhǎng)/m6折流板間距/mm200管子排列方式