空氣冷卻器分類及特點

1、濕式空冷器

濕(shi)(shi)(shi)式(shi)(shi)空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)根據噴(pen)水(shui)(shui)方式(shi)(shi)，可(ke)分為表面蒸(zheng)發型(xing)、增(zeng)濕(shi)(shi)(shi)型(xing)和(he)(he)噴(pen)淋(lin)型(xing)3種，在石化工業(ye)中以后(hou)兩種為主。表面蒸(zheng)發式(shi)(shi)空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)是一種利(li)用(yong)管外(wai)水(shui)(shui)膜(mo)蒸(zheng)發來強化傳(chuan)(chuan)(chuan)熱(re)(re)、由光管組成(cheng)的空(kong)(kong)(kong)冷(leng)裝置。增(zeng)濕(shi)(shi)(shi)型(xing)濕(shi)(shi)(shi)式(shi)(shi)空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)只適(shi)用(yong)于相(xiang)對(dui)濕(shi)(shi)(shi)度(du)低于50%的干(gan)燥、炎熱(re)(re)地區(qu)，因為干(gan)空(kong)(kong)(kong)氣相(xiang)對(dui)濕(shi)(shi)(shi)度(du)越小，增(zeng)濕(shi)(shi)(shi)后(hou)降溫(wen)越多，冷(leng)卻效(xiao)果(guo)越顯著。噴(pen)淋(lin)型(xing)濕(shi)(shi)(shi)式(shi)(shi)空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)是直(zhi)接(jie)在翅片(pian)管束上噴(pen)霧(wu)狀水(shui)(shui)，利(li)用(yong)水(shui)(shui)分蒸(zheng)發的潛熱(re)(re)交換(huan)和(he)(he)空(kong)(kong)(kong)氣被增(zeng)濕(shi)(shi)(shi)降溫(wen)來強化傳(chuan)(chuan)(chuan)熱(re)(re)，同時，水(shui)(shui)霧(wu)的存(cun)在可(ke)使空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)入口空(kong)(kong)(kong)氣溫(wen)度(du)接(jie)近環境濕(shi)(shi)(shi)球溫(wen)度(du)，提高了傳(chuan)(chuan)(chuan)熱(re)(re)平均溫(wen)差(cha)，在3%噴(pen)淋(lin)量下換(huan)熱(re)(re)系數可(ke)比干(gan)式(shi)(shi)空(kong)(kong)(kong)冷(leng)器(qi)(qi)(qi)提高2 ~4倍。

總之，相較(jiao)于干(gan)式(shi)(shi)(shi)空(kong)(kong)冷器，在(zai)炎(yan)熱的夏季，環境氣溫較(jiao)高(gao)時，應(ying)用濕(shi)式(shi)(shi)(shi)空(kong)(kong)冷器更為有利。但(dan)是，濕(shi)式(shi)(shi)(shi)空(kong)(kong)冷器在(zai)管(guan)內流體溫度超過70℃時，就極易結垢，且(qie)管(guan)外(wai)空(kong)(kong)氣阻力損失較(jiao)大，約為干(gan)式(shi)(shi)(shi)空(kong)(kong)冷的1.4倍(bei)。管(guan)束面積不(bu)能太大，故(gu)單元裝置的相對面積較(jiao)小，價格相對較(jiao)高(gao)。

該圖片由注冊用戶"安居樂"提供，版權聲明反饋

2、干式空冷器

干(gan)式(shi)空(kong)冷(leng)器僅依靠空(kong)氣(qi)(qi)溫升的(de)顯(xian)熱(re)方(fang)式(shi)來(lai)交換熱(re)量，靠翅片(pian)管和風機強制循環(huan)強化傳熱(re)。操作簡單，使(shi)用方(fang)便，但由于(yu)其冷(leng)卻溫度取決于(yu)空(kong)氣(qi)(qi)的(de)干(gan)球溫度，所以一般只(zhi)能把(ba)管內熱(re)流體冷(leng)卻到高于(yu)環(huan)境溫度15~20℃。

因(yin)此，對于(yu)我(wo)國南方濕(shi)熱(re)(re)地區，濕(shi)式(shi)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)蒸發效果不好，一般主(zhu)要(yao)用干式(shi)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)。從熱(re)(re)量(liang)傳(chuan)遞角度講，空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)的(de)(de)(de)比(bi)(bi)(bi)熱(re)(re)僅為(wei)(wei)(wei)水(shui)的(de)(de)(de)比(bi)(bi)(bi)熱(re)(re)的(de)(de)(de)1 /4，空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)的(de)(de)(de)密(mi)度也(ye)遠小于(yu)水(shui)的(de)(de)(de)密(mi)度，因(yin)此，若傳(chuan)遞相(xiang)同(tong)的(de)(de)(de)熱(re)(re)量(liang)，冷(leng)(leng)卻介質(zhi)溫升相(xiang)同(tong)，所(suo)需要(yao)的(de)(de)(de)空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)量(liang)將是水(shui)的(de)(de)(de)4倍，相(xiang)比(bi)(bi)(bi)于(yu)水(shui)冷(leng)(leng)卻器(qi)，干式(shi)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)的(de)(de)(de)體積是很大的(de)(de)(de)。最關(guan)鍵的(de)(de)(de)是，空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)側的(de)(de)(de)換熱(re)(re)系(xi)數很低，約為(wei)(wei)(wei)50~60W/(m2·℃)，導致光管(guan)(guan)(guan)(guan)(guan)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)的(de)(de)(de)總傳(chuan)熱(re)(re)系(xi)數很低，較(jiao)水(shui)冷(leng)(leng)卻器(qi)的(de)(de)(de)傳(chuan)熱(re)(re)系(xi)數約低10~30倍，為(wei)(wei)(wei)抵消空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)側換熱(re)(re)系(xi)數較(jiao)低的(de)(de)(de)影響，空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)一般均采用擴(kuo)展表(biao)面(mian)(mian)的(de)(de)(de)翅(chi)片(pian)管(guan)(guan)(guan)(guan)(guan)，其(qi)翅(chi)化比(bi)(bi)(bi)大致為(wei)(wei)(wei)10~24倍。也(ye)有(you)采用板式(shi)傳(chuan)熱(re)(re)元件(jian)的(de)(de)(de)板式(shi)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)，因(yin)為(wei)(wei)(wei)板片(pian)形(xing)成(cheng)(cheng)的(de)(de)(de)流(liu)(liu)(liu)道(dao)(dao)(dao)(dao)斷面(mian)(mian)形(xing)狀(zhuang)沿(yan)流(liu)(liu)(liu)動(dong)方向不斷變化，增強了擾動(dong)，在低雷(lei)諾數下具有(you)高的(de)(de)(de)傳(chuan)熱(re)(re)效率和低的(de)(de)(de)壓(ya)降，特(te)別適用于(yu)石化行業(ye)大型裝置(如大型乙烯成(cheng)(cheng)套設備等(deng))的(de)(de)(de)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)，但是由(you)于(yu)板式(shi)空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)的(de)(de)(de)流(liu)(liu)(liu)道(dao)(dao)(dao)(dao)狹窄，在我(wo)國北(bei)方寒冷(leng)(leng)的(de)(de)(de)冬(dong)季，容易引起(qi)流(liu)(liu)(liu)道(dao)(dao)(dao)(dao)內(nei)被(bei)冷(leng)(leng)卻介質(zhi)凝(ning)結而(er)(er)堵塞流(liu)(liu)(liu)道(dao)(dao)(dao)(dao)，并(bing)且易結垢從而(er)(er)堵塞流(liu)(liu)(liu)道(dao)(dao)(dao)(dao)，又由(you)于(yu)加(jia)工工藝(yi)多(duo)為(wei)(wei)(wei)全焊式(shi)結構，局部損壞(huai)或堵塞時，必須(xu)整臺更換空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)，造成(cheng)(cheng)很大浪費(fei)。所(suo)以，翅(chi)片(pian)管(guan)(guan)(guan)(guan)(guan)仍然是空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)的(de)(de)(de)主(zhu)流(liu)(liu)(liu)傳(chuan)熱(re)(re)元件(jian)，空(kong)(kong)(kong)(kong)(kong)(kong)冷(leng)(leng)器(qi)的(de)(de)(de)本質(zhi)可以看為(wei)(wei)(wei)是空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)－熱(re)(re)媒的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)翅(chi)式(shi)換熱(re)(re)器(qi)，強化空(kong)(kong)(kong)(kong)(kong)(kong)氣(qi)(qi)冷(leng)(leng)卻器(qi)傳(chuan)熱(re)(re)性能的(de)(de)(de)關(guan)鍵是研制低接觸熱(re)(re)阻、高傳(chuan)熱(re)(re)效能和流(liu)(liu)(liu)動(dong)阻力小的(de)(de)(de)翅(chi)片(pian)管(guan)(guan)(guan)(guan)(guan)。當(dang)換熱(re)(re)器(qi)內(nei)部為(wei)(wei)(wei)壓(ya)力較(jiao)高的(de)(de)(de)流(liu)(liu)(liu)體時，管(guan)(guan)(guan)(guan)(guan)外加(jia)肋，就(jiu)相(xiang)當(dang)于(yu)用不承(cheng)(cheng)壓(ya)的(de)(de)(de)廉價肋片(pian)取代承(cheng)(cheng)壓(ya)的(de)(de)(de)優質(zhi)管(guan)(guan)(guan)(guan)(guan)材，經濟(ji)效果顯著(zhu)。

3、干－濕聯合式空冷器

干(gan)(gan)－濕聯合(he)式(shi)(shi)空(kong)冷器，就是將干(gan)(gan)式(shi)(shi)空(kong)冷器與(yu)濕式(shi)(shi)空(kong)冷器組合(he)集成。組合(he)的一(yi)般原(yuan)則是，在(zai)工藝流體(ti)高溫(wen)(wen)區(qu)用(yong)干(gan)(gan)式(shi)(shi)空(kong)冷器，起(qi)氣(qi)體(ti)冷凝的作用(yong);在(zai)低(di)溫(wen)(wen)區(qu)使用(yong)濕式(shi)(shi)空(kong)冷器，起(qi)冷凝液冷卻的作用(yong)。總之，選(xuan)擇哪種形式(shi)(shi)的空(kong)冷器，要根據當(dang)地的大氣(qi)溫(wen)(wen)度(du)、風速及相對濕度(du)等(deng)環(huan)境氣(qi)候條件，結合(he)介質最終冷卻溫(wen)(wen)度(du)等(deng)換熱工藝要求，并兼顧(gu)經濟性，進行(xing)綜合(he)考(kao)量確定。

空氣冷卻器通風方式

1、鼓風式(shi)：空氣先(xian)流經通風機后流入管束。

2、引風式：空(kong)氣先流(liu)經管束(shu)后流(liu)入通風機。前者操作費用(yong)較經濟(ji)，產(chan)生的(de)湍流(liu)對(dui)傳熱有利，使用(yong)較多。

后(hou)者(zhe)氣流(liu)(liu)分布均勻，有利于溫度(du)(du)精確控制，噪聲小(xiao)，是發展的(de)(de)方向。熱流(liu)(liu)體出口(kou)溫度(du)(du)主要靠調節通過管束的(de)(de)風量來控制，即調節葉片(pian)的(de)(de)傾角(jiao)、通風機(ji)轉速和百葉窗(chuang)的(de)(de)開啟程度(du)(du)等。對冬季易(yi)凝(ning)、易(yi)凍的(de)(de)流(liu)(liu)體，可采用熱風循環或蒸汽加熱的(de)(de)辦法調節流(liu)(liu)體出口(kou)溫度(du)(du)。