碳素有限公司400kt/a預焙陽極電捕焦油器陽極板芒刺線廠家清單

碳(tan)素(su)廠焙(bei)(bei)燒煙(yan)氣(qi)凈化工藝系統(tong)概述：本工藝系統(tong)為田(tian)林(lin)百礦田(tian)田(tian)碳(tan)素(su)有限(xian)公司400kt/a預焙(bei)(bei)陽(yang)極(ji)碳(tan)素(su)項(xiang)目陽(yang)極(ji)焙(bei)(bei)燒煙(yan)氣(qi)凈化系統(tong)，共設(she)2套煙(yan)氣(qi)凈化系統(tong)，每套系統(tong)負(fu)責處理焙(bei)(bei)燒車間一臺焙(bei)(bei)燒爐(lu)（40室(shi)）所產(chan)生的煙(yan)氣(qi)，將煙(yan)氣(qi)中的瀝青煙(yan)、氟化物、粉塵、SO2凈化后達標(biao)排放。

根據焙(bei)(bei)燒爐(lu)煙(yan)(yan)(yan)氣(qi)(qi)特點(dian)，凈(jing)化(hua)系(xi)(xi)統(tong)采用(yong)“干法電(dian)捕+石(shi)灰石(shi)-石(shi)膏濕法脫(tuo)(tuo)硫、脫(tuo)(tuo)氟凈(jing)化(hua)處理”工藝方(fang)案，其中(zhong)(zhong)脫(tuo)(tuo)硫劑采用(yong)超細碳(tan)酸鈣粉末（CaCO3）（外購合(he)格粒(li)度的石(shi)灰石(shi)粉）。焙(bei)(bei)燒煙(yan)(yan)(yan)氣(qi)(qi)凈(jing)化(hua)工藝系(xi)(xi)統(tong)主要分(fen)為(wei)電(dian)捕焦(jiao)、脫(tuo)(tuo)硫脫(tuo)(tuo)氟兩個分(fen)項系(xi)(xi)統(tong)，以及配套(tao)的煙(yan)(yan)(yan)風系(xi)(xi)統(tong)等，每(mei)個分(fen)項系(xi)(xi)統(tong)由分(fen)為(wei)若干子系(xi)(xi)統(tong)。焙(bei)(bei)燒爐(lu)煙(yan)(yan)(yan)氣(qi)(qi)中(zhong)(zhong)含有大(da)(da)量的瀝青(qing)煙(yan)(yan)(yan)、氟化(hua)物、粉塵、SO2等污染物，其中(zhong)(zhong)瀝青(qing)煙(yan)(yan)(yan)、焦(jiao)油(you)通過電(dian)捕焦(jiao)系(xi)(xi)統(tong)去除。焙(bei)(bei)燒爐(lu)出(chu)口煙(yan)(yan)(yan)氣(qi)(qi)溫(wen)度120-250℃，最高可達350℃，根據國內大(da)(da)多數碳(tan)素廠焙(bei)(bei)燒爐(lu)運行(xing)經驗，系(xi)(xi)統(tong)入(ru)(ru)口煙(yan)(yan)(yan)氣(qi)(qi)溫(wen)度長時間維持在120-150℃的溫(wen)度區間；高溫(wen)煙(yan)(yan)(yan)氣(qi)(qi)首先(xian)進(jin)入(ru)(ru)噴霧(wu)冷(leng)卻塔(ta)，冷(leng)卻塔(ta)采用(yong)全(quan)蒸發設計，煙(yan)(yan)(yan)氣(qi)(qi)從(cong)塔(ta)上部(bu)進(jin)入(ru)(ru)，向下與霧(wu)化(hua)噴入(ru)(ru)的冷(leng)卻水順流接觸，將(jiang)(jiang)水迅速霧(wu)化(hua)，煙(yan)(yan)(yan)氣(qi)(qi)溫(wen)度下降至90℃左右，瀝青(qing)煙(yan)(yan)(yan)變成小液滴(di)，并從(cong)塔(ta)底排出(chu)進(jin)入(ru)(ru)電(dian)捕焦(jiao)油(you)器，在高壓電(dian)場作用(yong)下，將(jiang)(jiang)煙(yan)(yan)(yan)氣(qi)(qi)中(zhong)(zhong)的焦(jiao)油(you)、粉塵捕集并排出(chu)，凈(jing)化(hua)后煙(yan)(yan)(yan)氣(qi)(qi)進(jin)入(ru)(ru)引(yin)風機。

電捕焦分(fen)(fen)項系(xi)統(tong)(tong)分(fen)(fen)為(wei)(wei)(wei)全蒸發(fa)霧(wu)(wu)化冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)、噴(pen)霧(wu)(wu)閥架、冷(leng)(leng)(leng)(leng)卻(que)(que)水(shui)、電捕焦油(you)器(qi)等(deng)子系(xi)統(tong)(tong)。全蒸發(fa)噴(pen)霧(wu)(wu)冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)按照全蒸發(fa)設(she)計，每臺40室焙燒爐配備一臺，單臺處(chu)理煙氣(qi)量為(wei)(wei)(wei)180000Nm3/h。煙氣(qi)為(wei)(wei)(wei)上進(jin)下(xia)出，冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)底部(bu)為(wei)(wei)(wei)錐體結構，設(she)置排油(you)閥；冷(leng)(leng)(leng)(leng)卻(que)(que)水(shui)在(zai)煙氣(qi)進(jin)口上方噴(pen)入，采(cai)用霧(wu)(wu)化、全覆蓋方式，以保證(zheng)水(shui)與煙氣(qi)的充分(fen)(fen)混合和快速(su)蒸發(fa)，為(wei)(wei)(wei)延長煙氣(qi)停留時間(jian)、增加蒸發(fa)效果，噴(pen)霧(wu)(wu)位置距離煙氣(qi)出口不小于21米。冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)按照煙氣(qi)進(jin)口溫(wen)度(du)150℃進(jin)行設(she)計，可在(zai)100-200℃溫(wen)度(du)區間(jian)內(nei)正常運行，冷(leng)(leng)(leng)(leng)卻(que)(que)塔(ta)(ta)(ta)出口溫(wen)度(du)90±2℃，噴(pen)入的冷(leng)(leng)(leng)(leng)卻(que)(que)水(shui)為(wei)(wei)(wei)全部(bu)蒸發(fa)，不產生廢水(shui)，但(dan)底部(bu)會有少量焦油(you)排出。

由于采取濕法降溫(wen)方式，煙氣(qi)出口溫(wen)度(du)較低，因此設備內部存在干(gan)濕界(jie)面、酸(suan)露點等腐蝕情況，需要進(jin)行防(fang)腐處理。塔外壁需要進(jin)行保溫(wen)，保溫(wen)形式采用巖棉彩鋼瓦形式，保溫(wen)厚度(du)為75mm.。顏色由乙(yi)方發函甲方，最終確認(ren)。

本方案全蒸發(fa)噴霧(wu)冷卻塔采用鋼結構形式(shi)。下部錐斗及噴淋段以(yi)下采用12mm碳鋼板(ban)制(zhi)做，噴淋段以(yi)上采用10mm鋼板(ban)制(zhi)做，外(wai)部設置加強筋。全蒸發(fa)噴霧(wu)冷卻塔內(nei)外(wai)表(biao)面(mian)(mian)刷防腐(fu)漆(qi)，刷漆(qi)前須對設備內(nei)外(wai)表(biao)面(mian)(mian)進行ST3級除(chu)銹(xiu)，然后塔體(ti)外(wai)表(biao)面(mian)(mian)涂刷W06耐(nai)高溫(wen)防腐(fu)底漆(qi)兩道(dao)，塔體(ti)內(nei)表(biao)面(mian)(mian)及塔內(nei)所有(you)附(fu)件涂刷W61-2有(you)機硅(gui)耐(nai)高溫(wen)防腐(fu)漆(qi)底漆(qi)兩道(dao)，面(mian)(mian)漆(qi)兩道(dao)。

電捕(bu)焦油器工藝原理(li)：

電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)焦油器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源也是提(ti)高(gao)粉塵(chen)驅進(jin)速(su)度(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)重要(yao)方面(mian)，提(ti)高(gao)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)水平可(ke)以在(zai)(zai)節(jie)(jie)能(neng)(neng)的(de)(de)(de)(de)(de)(de)(de)同(tong)(tong)時(shi)，有(you)(you)效(xiao)(xiao)收集高(gao)比(bi)(bi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻粉塵(chen)，提(ti)高(gao)捕(bu)(bu)集效(xiao)(xiao)率(lv)。傳統(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)為直流脈(mo)(mo)動，現(xian)在(zai)(zai)常采用與(yu)常規電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源不(bu)同(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)間(jian)(jian)(jian)(jian)(jian)歇(xie)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)技(ji)術來(lai)改變粉塵(chen)的(de)(de)(de)(de)(de)(de)(de)荷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)特(te)性(xing)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)器(qi)(qi)采用脈(mo)(mo)沖(chong)間(jian)(jian)(jian)(jian)(jian)歇(xie)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控制方式(shi)的(de)(de)(de)(de)(de)(de)(de)目的(de)(de)(de)(de)(de)(de)(de)是提(ti)高(gao)二(er)次瞬(shun)(shun)間(jian)(jian)(jian)(jian)(jian)峰(feng)值(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)、瞬(shun)(shun)間(jian)(jian)(jian)(jian)(jian)峰(feng)值(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流、減(jian)小一次電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流。它的(de)(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)實質在(zai)(zai)于三相(xiang)高(gao)壓(ya)間(jian)(jian)(jian)(jian)(jian)隙(xi)脈(mo)(mo)沖(chong)具(ju)有(you)(you)一定重復頻率(lv)、寬度(du)(du)(du)很窄而(er)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)峰(feng)值(zhi)又很高(gao)的(de)(de)(de)(de)(de)(de)(de)間(jian)(jian)(jian)(jian)(jian)隙(xi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。間(jian)(jian)(jian)(jian)(jian)隙(xi)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)是在(zai)(zai)很短的(de)(de)(de)(de)(de)(de)(de)時(shi)間(jian)(jian)(jian)(jian)(jian)內在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)上(shang)施(shi)加(jia)快速(su)上(shang)升(sheng)的(de)(de)(de)(de)(de)(de)(de)脈(mo)(mo)沖(chong)，提(ti)高(gao)了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場擊穿電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，所以施(shi)加(jia)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場上(shang)的(de)(de)(de)(de)(de)(de)(de)峰(feng)值(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)比(bi)(bi)常規電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)一般高(gao) 1. 5 倍～ 2倍; 脈(mo)(mo)沖(chong)間(jian)(jian)(jian)(jian)(jian)歇(xie)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，陰極(ji)具(ju)有(you)(you)非常均(jun)勻(yun)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)分布和(he)很強的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)力，從而(er)提(ti)高(gao)了粉塵(chen)的(de)(de)(de)(de)(de)(de)(de)荷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)概率(lv);可(ke)在(zai)(zai)脈(mo)(mo)沖(chong)峰(feng)值(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)基(ji)本不(bu)變的(de)(de)(de)(de)(de)(de)(de)條件下，根據粉塵(chen)特(te)性(xing)，不(bu)同(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場采取不(bu)同(tong)(tong)脈(mo)(mo)沖(chong)間(jian)(jian)(jian)(jian)(jian)歇(xie)比(bi)(bi)，在(zai)(zai)不(bu)同(tong)(tong)間(jian)(jian)(jian)(jian)(jian)歇(xie)比(bi)(bi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)平均(jun)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流也不(bu)同(tong)(tong)，創造不(bu)同(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)節(jie)(jie)能(neng)(neng)效(xiao)(xiao)率(lv)，因此，對粉塵(chen)性(xing)質的(de)(de)(de)(de)(de)(de)(de)變化有(you)(you)良好的(de)(de)(de)(de)(de)(de)(de)適應(ying)(ying)性(xing)，由(you)其(qi)在(zai)(zai)末極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場有(you)(you)利于克服(fu)”反(fan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)”現(xian)象(xiang)，可(ke)以明顯(xian)降低運行電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，節(jie)(jie)能(neng)(neng)效(xiao)(xiao)果(guo)顯(xian)著(zhu);三相(xiang)脈(mo)(mo)沖(chong)間(jian)(jian)(jian)(jian)(jian)歇(xie)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)這(zhe)些特(te)點使其(qi)在(zai)(zai)當今電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)器(qi)(qi)應(ying)(ying)用領域獲得越來(lai)越多的(de)(de)(de)(de)(de)(de)(de)認可(ke)。三相(xiang)高(gao)壓(ya)脈(mo)(mo)沖(chong)間(jian)(jian)(jian)(jian)(jian)歇(xie)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)使極(ji)板(ban)間(jian)(jian)(jian)(jian)(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場強度(du)(du)(du)增大，使極(ji)板(ban)間(jian)(jian)(jian)(jian)(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流密度(du)(du)(du)分布均(jun)勻(yun)性(xing)趨好，改善電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)運行狀(zhuang)況(kuang)，有(you)(you)效(xiao)(xiao)抑制“電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)封閉”及“反(fan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)(yun)”現(xian)象(xiang)，提(ti)高(gao)粉塵(chen)的(de)(de)(de)(de)(de)(de)(de)荷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量，提(ti)高(gao)塵(chen)粒的(de)(de)(de)(de)(de)(de)(de)驅進(jin)速(su)度(du)(du)(du)，提(ti)高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)捕(bu)(bu)器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)除塵(chen)效(xiao)(xiao)率(lv)和(he)高(gao)效(xiao)(xiao)節(jie)(jie)能(neng)(neng)

電捕焦(jiao)油收塵器的(de)防(fang)腐(fu)蝕與結露(lu)(lu)一對相關(guan)聯的(de)問(wen)題， 首先做(zuo)到避免結露(lu)(lu)來(lai)防(fang)腐(fu)，然后是(shi)(shi)結露(lu)(lu)能運行，主要構件耐腐(fu)蝕，要想做(zuo)到避免結露(lu)(lu)對本(ben)次電捕焦(jiao)油器設計(ji)來(lai)講是(shi)(shi)比較容(rong)易的(de)事，保(bao)證煙氣(qi)高于露(lu)(lu)點(dian)溫度即可(ke)，但是(shi)(shi)結露(lu)(lu)往(wang)往(wang)不是(shi)(shi)存在于整個(ge)電場(chang)空間(jian)而是(shi)(shi)在局部(bu)(bu)漏風嚴(yan)重的(de)地方(fang)，人孔(kong)門(men)(men)或頂部(bu)(bu)檢修孔(kong)等可(ke)開啟部(bu)(bu)位，人孔(kong)門(men)(men)使用成雙(shuang)層(ceng)人孔(kong)門(men)(men)以確保(bao)并控制零的(de)漏風率。同時采用空氣(qi)夾層(ceng)巖(yan)棉雙(shuang)層(ceng)保(bao)溫的(de)方(fang)法。即殼體板外(wai)側先加一層(ceng)50毫(hao)米厚(hou)的(de)巖(yan)棉，再用支(zhi)架(jia)支(zhi)起一空氣(qi)夾層(ceng)200毫(hao)米外(wai)貼金屬護板，保(bao)證其保(bao)溫效果(guo)。

為了結露(lu)運(yun)行(xing)和耐(nai)腐蝕，在所有(you)陰陽級有(you)接觸部(bu)位加(jia)復合結角絕緣(yuan)保護，防止結露(lu)常(chang)導(dao)至爬(pa)電，爬(pa)電嚴重導(dao)致(zhi)電場擊(ji)穿(chuan)，保證(zheng)在結露(lu)時電收塵能夠正常(chang)運(yun)行(xing)，并增加(jia)內件防腐處理，

27000風量的電捕焦油器配置單：電捕焦(jiao)油器(qi)設計技(ji)術參數(shu)為：