電加熱設(shè)計(jì)資料

計(jì)量單位1.計(jì)量單位1.功率:W、kW重量：kg流速：m/min流量：m3/min、kg/h比熱:Kcal/(kg°C)6?功率密度：W/cm27.壓力:MPa8?導(dǎo)熱系數(shù)：W/(mC)9?溫度：C電熱設(shè)計(jì)資料1kW=3.412BTU/hr(英熱單位/小時(shí))=1.36(馬力)=864Kcal/hr1kg=2.204621b(磅)1kcal/(kgC)=1BTU/hr.oF=4186.8J/(KgC)1W/c^=6.4516W/in21W/(m°C)=0.01J/(cmsC)=0.578Btu/(ft.h.F)1oF=9/5C＋321R=9/5C＋491.671K=1C＋273.15電加熱功率計(jì)算加熱功率的計(jì)算有以下三個(gè)方面：即運(yùn)行時(shí)的功率 越啟動(dòng)時(shí)的功率 的系統(tǒng)中的熱損失所有的計(jì)算應(yīng)以最惡劣的情況考慮：卸最低的環(huán)境溫度和最短的運(yùn)行周期即最高的運(yùn)行溫度別加熱介質(zhì)的最大重量(流動(dòng)介質(zhì)則為最大流量)設(shè)計(jì)電加熱器系統(tǒng)的步驟暫根據(jù)工藝過(guò)程，畫出加熱的工藝流程圖(不涉及材料形式及規(guī)格)。腐計(jì)算工藝過(guò)程所需的熱量。腐計(jì)算系統(tǒng)起動(dòng)時(shí)所需的熱量及時(shí)間。

野重畫加熱工藝流程圖，考慮合適的安全系數(shù)，確定加熱器的總功率。決定發(fā)熱元件的護(hù)套材料及功率密度。暫決定加熱器的形式尺寸及數(shù)量。腐決定加熱器的電源及控制系統(tǒng)。有關(guān)加熱功率在理想狀態(tài)下的計(jì)算公式如下：EI系統(tǒng)起動(dòng)時(shí)所需要的功率:(mixcl+m2xc2)xATS64xhQ2x1000(mixcl+m2xc2)xATS64xhQ2x1000A-1E!系統(tǒng)運(yùn)行時(shí)所需要的功率:A-21000m3xcdhATA-21000P= 864^h加熱系統(tǒng)的散熱量E!管道2kxAt2kxAtP= xL A-31N(d+25)/d式中符號(hào)，含義如下:P式中符號(hào)，含義如下:P功率:kWml介質(zhì)重量：kgcl介質(zhì)比熱:kcal/kg°Cm2容器重量：kgc2介質(zhì)比熱:kcal/kgCm3每小時(shí)增加的介質(zhì)重量或流量:kg/hc3介質(zhì)比熱:kcal/kgCh加熱時(shí)間：hQ散熱量：管道為W/m；平面為W/m2入保溫材料的導(dǎo)熱數(shù)：W/mk6保溫材料厚度：mmd管道外徑：mmL管道長(zhǎng)度：mS系統(tǒng)的散熱面積：m2△T介質(zhì)和環(huán)境溫度之差或溫升：C有關(guān)加熱功率計(jì)算的參考數(shù)據(jù)（如需更多數(shù)據(jù)，請(qǐng)來(lái)電、來(lái)函咨詢）各種物質(zhì)的比熱(25°C)cal/(g°C)kcal/(kg°C)物質(zhì)比熱物質(zhì)比熱物質(zhì)比熱物質(zhì)比熱氫氣3.41乙醇0.55導(dǎo)熱油0.46玻璃0.200水1.00丙醇0.67二氧化碳0.24銀0.056冰0.50丁醇0.69氨0.52錫0.051酒精0.58丙酮0.51空氣0.24汞0.033甘油0.58石油0.52軟木塞0.49鋅0.090乙醚0.56石蠟0.77瀝青0.40鋁0.215煤油0.51蜂蠟0.82硬橡膠0.34爐渣0.180機(jī)油0.40醋酸0.42ABS塑料0.35鎳0.106松香水0.42硫磺0.24陶瓷0.26鋼0.120氮?dú)?.25硫酸0.34混凝土0.21生鐵0.130苯0.34橄欖油0.47巖鹽0.22鐵0.118甲苯0.44蓖麻油0.43無(wú)定形碳0.17黃銅0.090萘0.40天然氣0.60硫0.18銅0.092甲醇0.60氯化氫0.20水泥0.19石墨0.174各種氣體和蒸汽的定容定壓比熱cal/（gC）kcal/（kgC）物質(zhì)溫度（°C）定壓比熱（Cp）定容比熱（Cv）氫163.412.42氦181.250.75氨200.510.39水蒸汽100-3000.470.36酒精蒸汽108-2200.450.40乙醚蒸汽25-1110.430.40氮200.250.18氧化碳180.250.18空氣20-1000.240.17氧200.220.16二氧化碳200.200.15氯化氫22-2140.190.13各種物質(zhì)的密度物質(zhì)比重物質(zhì)比重物質(zhì)比重氣體（0°C和標(biāo)準(zhǔn)大氣壓下,g/cm3)氫0.00009甲烷0.00078氦0.00018乙炔0.00117氖0.00090氧化碳0.00125氮0.00125空氣0.00129氧0.00143氧化氮0.00134氟0.001696硫化氫0.00154

氬0.00178二氧化碳0.00198臭氧0.00214二氧化氮0.00198氯0.00321氰0.00234氪0.00374二氧化硫0.00293氙0.00589溴化氫0.00364氡0.00973碘化氫0.00579煤氣0.00060氨0.0007汽油0.70橄欖油0.92硝酸乙醚汽油0.70橄欖油0.92硝酸乙醚0.71魚肝油0.95硫酸石油0.76蓖麻油0.97溴酒精0.79純水1.00水銀木精0.80海水1.03煤油0.80醋酸1.05松節(jié)油0.86鹽酸1.20苯0.88無(wú)水甘油1.26礦油0.9-0.93二硫化碳1.29植物油0.9-0.93蜂蜜1.40液體（常溫g/cm3）1.501.803.1214.20鑄鋼7.80鉛11.34有機(jī)玻璃碳鋼7.80-7.85鎂1.738石灰石鑄鐵6.80-7.20鋅7.133瀝青鋁2.70鉻7.19白磷銀10.49錳7.43碳金19.302鈉0.97銅8.93鎢19.254康銅8.90鉭16.60鎳8.90錫5.765鎳鉻8.40鉑21.45固體（常溫g/cm3）1.182.60-3.00.90-1.501.821.90-2.30材料

玻璃纖維巖棉最高使用溫度材料

玻璃纖維巖棉最高使用溫度（°C）300物質(zhì)溶點(diǎn)（C）溶解熱（cal/g）沸點(diǎn)（C）汽化熱（cal/g）乙醚-11723.543584酒精-11423.5478204二硫化碳-11245.346.2584冰080100539各種保溫材料的導(dǎo)熱系數(shù)和最高使用溫度

礦渣棉3500.040膨漲珍珠巖5500.047聚氨脂泡沫塑料800.024聚苯稀泡沫塑料600.031硅酸鈣5500.054復(fù)合硅酸鹽氈FHP-VB7000.024復(fù)合硅酸鹽FHP-V涂料7000.024硅酸鋁（干法制造）4000.046硅酸鋁（濕法制造）8000.046注：準(zhǔn)確的數(shù)據(jù)請(qǐng)查供應(yīng)商的說(shuō)明書不同溫度下，不同管徑的保溫材料的厚度材料:巖棉外表封皮：鋁或不銹鋼 濕度：1% 環(huán)境溫度：5.4°C 風(fēng)速：3.8m/s管道直徑 管道溫度（C）英寸/公稱直徑/毫米2550花1001251501752002252502753003253503754004254501/2〃/15/21.342530303040505050606060808080808080803/4〃/20/26.672530304040505060606070808080808080801〃/25/33.402530404040506060607070808080808080801/2〃/40/48.262530404050506060707070909090909090902〃/50/60.33304040505060607070707090901001001001201203〃/80/88.903040405050607070708080901101101201301301504〃/100/1140330405050506070808090901001001101201301301606〃/150/168.330405060707080801001001001101301301301301601608〃/200/219.1405050607080809010010010011013013013015017018010〃/250/273.14050606070808010010010012012014014017017018019012〃/300/323.94050606070808010010010012014014017017018019020014〃/350/355.64060606070808010010010014014017017018019020020016〃/400/406.44060608080809010010010014015017018018019020021018〃/450/457.2406060808090901001001101501601701801801902221020〃/500/508.060606080909010010010012016016018019020021022022024〃/600/609.6060606080909010010010012017017019020020021022022026〃/650/660.406060601001009010013013014020020020020020021022022028〃/700/711.206060701001009011013013014020020020020020021022022030〃/750/762.060607010010010011013013017020020020020020021022028036〃/900/91404070709010010010011016017018020020020020020021022028040〃/1000/1016.070709010010010011017018019020020020020020028028029042〃/1050/1066.8070709010010010011017018019020020020020028028029030048〃/1200/1219.20707090100100100110170190190200200200200290300300300

54〃/1350/1371.6060〃/1500/1524.0066〃/1650/1676.8072〃/1800/1828.80罐體r\rf.*仲丄匚二eZ4-P4?707070707070707080100100100100100100100100100100100100100100100100100150100160100170100170180200180180190190200190200200200200190200200200300200200200200300200200200200300200280280280300280280300300300300300300300300300300300300300300300300300400300300300300400以上數(shù)據(jù)僅供參考常用的設(shè)計(jì)圖表在工程的計(jì)算和電加熱器的選型中，經(jīng)常要涉及到一些常用數(shù)據(jù)，如介質(zhì)表面的熱損失、介質(zhì)在不同工況下的溫度變化等。為了防止在電加熱器工作的同時(shí)，對(duì)介質(zhì)的性能和加熱元件產(chǎn)生不必要的損傷，下面列出了部分圖表，供選型參考。強(qiáng)迫對(duì)流下加熱器功率密度的選擇（空氣，環(huán)境溫度20c）65060055050045040035030025020015010050出口溫度。c出口流速m/min出口流速m/min水表面的熱損失（環(huán)境溫度20c）熱損失kW/m2

表面溫度C表面溫度C表面溫度C表面溫度C熱損失kW/m2溶融金屬表面的熱損失（鋁、巴氏合金、錫，環(huán)境溫度20C）熱損失kW/m25432101111119876543丁汁4丄丄，丄ij.llT~t^pT.T.+:十丄；丄i一一I ?■ ■■ ■―5432101111119876543丁汁4丄丄，丄ij.llT~t^pT.T.+:十丄；丄i一一I ?■ ■■ ■―1 ri L■150200「■FT!」…：一!T;:!300400500表面溫度￡5?陶瓷纖維絕熱層表面的熱損失（64kg/m3,環(huán)境溫度20°C）熱損失kW/m2e--i—「--1--4:I十1002003004005006007006.