樊玉新1,李泓洲(zhou)2,段勝(sheng)男1,顧鵬(peng)程2,任寧1
1.新疆油(you)田分公司工程技術研究(jiu)院(監理公司)
2.中新碳(tan)合科技(北京)有限公司
摘要:新(xin)(xin)疆(jiang)(jiang)油田(tian)公司近期在(zai)某井區(qu)開(kai)(kai)展高溫(wen)光(guang)熱(re)制蒸(zheng)(zheng)(zheng)汽(qi)與(yu)注汽(qi)鍋爐耦合的(de)(de)(de)(de)先導試驗,為稠(chou)(chou)油蒸(zheng)(zheng)(zheng)汽(qi)輔助(zhu)重力泄油(SAGD)開(kai)(kai)發提供低碳(tan)(tan)高品質蒸(zheng)(zheng)(zheng)汽(qi)。先導試驗的(de)(de)(de)(de)開(kai)(kai)展對油氣勘探(tan)開(kai)(kai)發與(yu)新(xin)(xin)能(neng)源技(ji)術(shu)的(de)(de)(de)(de)融(rong)合具有先行示范意(yi)義。“雙碳(tan)(tan)”目標(biao)下新(xin)(xin)疆(jiang)(jiang)油田(tian)公司稠(chou)(chou)油生產(chan)面臨減少天然(ran)氣消耗,降(jiang)低二氧(yang)化碳(tan)(tan)排(pai)放的(de)(de)(de)(de)挑戰(zhan)。結合太陽能(neng)聚光(guang)集熱(re)技(ji)術(shu)、綠電(dian)+電(dian)極熔(rong)鹽加熱(re)技(ji)術(shu)、高溫(wen)儲熱(re)技(ji)術(shu),提出不(bu)同場景下淺(qian)層稠(chou)(chou)油開(kai)(kai)采(cai)中注汽(qi)工(gong)藝的(de)(de)(de)(de)新(xin)(xin)能(neng)源供能(neng)配置(zhi)方(fang)案。為太陽能(neng)高溫(wen)光(guang)熱(re)技(ji)術(shu)在(zai)新(xin)(xin)疆(jiang)(jiang)油田(tian)稠(chou)(chou)油作業(ye)區(qu)規模化應(ying)用(yong)提供了具體思路(lu)與(yu)解決方(fang)法(fa),在(zai)減少自(zi)用(yong)天然(ran)氣的(de)(de)(de)(de)同時(shi)盡(jin)可能(neng)降(jiang)低蒸(zheng)(zheng)(zheng)汽(qi)成本,對稠(chou)(chou)油油田(tian)低碳(tan)(tan)可持(chi)續(xu)開(kai)(kai)發具有重要指(zhi)導意(yi)義。
關鍵(jian)詞:太陽能聚(ju)光集熱;熔鹽儲熱;超稠油;直接產蒸汽;連續(xu)產蒸汽;低碳開(kai)發
中圖分類(lei)號:TE345文獻(xian)標識碼(ma):A
準噶爾(er)盆地蘊(yun)藏豐富的(de)石油(you)和(he)天(tian)然(ran)氣資(zi)源,其(qi)中盆地西北緣是淺層(ceng)超稠(chou)油(you)富集(ji)帶,具有(you)埋深淺、溶解氣量小、天(tian)然(ran)驅動(dong)能(neng)(neng)量弱、黏度特別高(gao)的(de)特點。通過對稠(chou)油(you)油(you)藏注(zhu)入高(gao)溫高(gao)壓蒸汽,降(jiang)低(di)稠(chou)油(you)黏度增加流動(dong)性是開發淺層(ceng)超稠(chou)油(you)的(de)有(you)效方(fang)法。目前主(zhu)要通過燃燒煤炭、天(tian)然(ran)氣等(deng)化石燃料生(sheng)產蒸汽,能(neng)(neng)源消耗(hao)高(gao)。據統計,注(zhu)汽系統能(neng)(neng)耗(hao)約占稠(chou)油(you)生(sheng)產總能(neng)(neng)耗(hao)的(de)98.6%。
國家能源(yuan)局近期提出(chu)油(you)氣勘探開(kai)發(fa)要與新能源(yuan)融(rong)合發(fa)展,要求(qiu)加大(da)油(you)氣勘探開(kai)發(fa)與新能源(yuan)融(rong)合的(de)(de)技術(shu)創(chuang)新攻(gong)關力(li)度(du)。新疆維吾爾自治區也大(da)力(li)提倡綠色生(sheng)產(chan),特別要加快(kuai)煤炭、石油(you)、化工三大(da)重點行(xing)業(ye)的(de)(de)低(di)碳(tan)轉型(xing)。因此,充分利(li)用新疆地區豐(feng)富的(de)(de)太陽(yang)能資源(yuan),通過(guo)聚光(guang)集熱及儲(chu)熱技術(shu),實現(xian)油(you)氣生(sheng)產(chan)過(guo)程的(de)(de)清潔化供熱,助力(li)低(di)碳(tan)油(you)氣開(kai)發(fa)。
1、太陽能高溫光熱制蒸汽技術概述
太陽(yang)(yang)能(neng)聚(ju)光(guang)(guang)集熱(re)(re)(re)技術(shu)主要應用于太陽(yang)(yang)能(neng)熱(re)(re)(re)發(fa)電領域。在稠(chou)油蒸(zheng)(zheng)(zheng)汽驅油開采(cai)(cai)方面美(mei)國(guo)(guo)、阿(a)曼(man)都曾開展過太陽(yang)(yang)能(neng)光(guang)(guang)熱(re)(re)(re)制(zhi)蒸(zheng)(zheng)(zheng)汽示(shi)(shi)范項(xiang)目(mu)。其中(zhong)2010年(nian)阿(a)曼(man)建成Miraah 7 MW示(shi)(shi)范裝置(zhi)(北(bei)緯23o),采(cai)(cai)用封閉(bi)式(shi)(shi)槽式(shi)(shi)光(guang)(guang)熱(re)(re)(re)系統,日產(chan)蒸(zheng)(zheng)(zheng)汽達50 t;美(mei)國(guo)(guo)雪佛龍公司(si)在加(jia)州(zhou)科林(lin)納(北(bei)緯36o)建設(she)29 MW光(guang)(guang)熱(re)(re)(re)制(zhi)蒸(zheng)(zheng)(zheng)汽示(shi)(shi)范裝置(zhi),采(cai)(cai)用塔式(shi)(shi)集熱(re)(re)(re)技術(shu),2011—2014年(nian)運行效果(guo)良好。新疆油田公司(si)正在某井區(qu)開展高(gao)溫光(guang)(guang)熱(re)(re)(re)耦合注汽鍋爐聯合供蒸(zheng)(zheng)(zheng)汽的(de)先導試驗項(xiang)目(mu)。該(gai)井區(qu)地處(chu)北(bei)緯46o,每年(nian)日照(zhao)時長(chang)達2 637 h,多年(nian)太陽(yang)(yang)能(neng)平均法向直接輻射量(liang)(DNI)1 360 kW·h/m2,光(guang)(guang)資(zi)(zi)源(yuan)呈現冬夏季分布(bu)不均勻的(de)特(te)點,為此選取聚(ju)光(guang)(guang)比高(gao)的(de)塔式(shi)(shi)光(guang)(guang)熱(re)(re)(re)技術(shu)路線。采(cai)(cai)用北(bei)鏡場布(bu)置(zhi)提高(gao)鏡場余弦(xian)效率,以軟化清(qing)水作(zuo)為集熱(re)(re)(re)介質直接在吸熱(re)(re)(re)器中(zhong)生(sheng)成蒸(zheng)(zheng)(zheng)汽。采(cai)(cai)取與注汽鍋爐耦合運行方式(shi)(shi),不設(she)置(zhi)地面儲熱(re)(re)(re)設(she)施,利用SAGD采(cai)(cai)油工(gong)藝形成的(de)地下汽腔(qiang)作(zuo)為緩沖(chong),平抑(yi)光(guang)(guang)資(zi)(zi)源(yuan)變化對蒸(zheng)(zheng)(zheng)汽量(liang)波動造成的(de)影響,項(xiang)目(mu)效果(guo)圖見(jian)圖1。
圖1某井(jing)區高溫光熱制蒸汽試驗(yan)項目效果(guo)圖
項目配置的(de)高溫光熱(re)(re)(re)(re)直接制蒸汽(CS-DSG)系(xi)(xi)(xi)(xi)統可分為聚(ju)(ju)光集(ji)熱(re)(re)(re)(re)系(xi)(xi)(xi)(xi)統、水(shui)工(gong)質(zhi)吸(xi)(xi)熱(re)(re)(re)(re)器(qi)(蒸汽發生系(xi)(xi)(xi)(xi)統)、汽水(shui)系(xi)(xi)(xi)(xi)統和電氣及熱(re)(re)(re)(re)工(gong)控(kong)制系(xi)(xi)(xi)(xi)統等。聚(ju)(ju)光集(ji)熱(re)(re)(re)(re)系(xi)(xi)(xi)(xi)統收集(ji)太(tai)陽(yang)(yang)能,反(fan)射太(tai)陽(yang)(yang)光并聚(ju)(ju)焦至吸(xi)(xi)熱(re)(re)(re)(re)器(qi),利用太(tai)陽(yang)(yang)能輻(fu)射熱(re)(re)(re)(re)加熱(re)(re)(re)(re)吸(xi)(xi)熱(re)(re)(re)(re)器(qi)內(nei)的(de)水(shui)工(gong)質(zhi),給水(shui)進(jin)入吸(xi)(xi)熱(re)(re)(re)(re)器(qi)的(de)蒸發段(duan)、汽包和過熱(re)(re)(re)(re)器(qi)后形成高品質(zhi)過熱(re)(re)(re)(re)蒸汽。CS-DSG系(xi)(xi)(xi)(xi)統工(gong)藝流(liu)程(cheng)見圖2。
圖2 CS-DSG系(xi)統工藝流程
時(shi)蒸(zheng)汽(qi)(qi)出力(li)受到(dao)影(ying)響,增加高(gao)溫熔鹽儲(chu)熱系(xi)統并(bing)配(pei)置蒸(zheng)汽(qi)(qi)發生器后(hou)可平(ping)抑光資源波(bo)動造成(cheng)的(de)蒸(zheng)汽(qi)(qi)出力(li)影(ying)響。配(pei)置儲(chu)熱裝(zhuang)置的(de)高(gao)溫光熱連續制蒸(zheng)汽(qi)(qi)(CSSGS)系(xi)統工藝流程見圖(tu)3。
CS-SGS系統增加(jia)了儲(chu)熱(re)(re)(re)裝置,以熔(rong)鹽(yan)作為(wei)吸熱(re)(re)(re)和儲(chu)熱(re)(re)(re)介質(zhi),采用冷、熱(re)(re)(re)鹽(yan)罐的(de)雙(shuang)罐儲(chu)熱(re)(re)(re)方式(shi),并(bing)配套(tao)熔(rong)鹽(yan)-蒸(zheng)(zheng)汽(qi)發(fa)生(sheng)系統。加(jia)熱(re)(re)(re)后的(de)熔(rong)鹽(yan)從熱(re)(re)(re)鹽(yan)罐進(jin)(jin)入(ru)蒸(zheng)(zheng)汽(qi)發(fa)生(sheng)器與水工質(zhi)進(jin)(jin)行(xing)換(huan)熱(re)(re)(re),把給水加(jia)熱(re)(re)(re)成過熱(re)(re)(re)蒸(zheng)(zheng)汽(qi),換(huan)熱(re)(re)(re)后的(de)熔(rong)鹽(yan)回到(dao)冷鹽(yan)罐中(zhong)并(bing)通(tong)過冷鹽(yan)泵送入(ru)吸熱(re)(re)(re)塔吸收太陽(yang)能,太陽(yang)能以顯熱(re)(re)(re)的(de)方式(shi)存儲(chu)在熱(re)(re)(re)鹽(yan)中(zhong)。
圖3 CS-SGS系統工藝流程
高(gao)(gao)(gao)溫(wen)熔(rong)(rong)(rong)(rong)鹽(yan)儲(chu)(chu)(chu)熱(re)(re)技術在(zai)(zai)太(tai)陽能(neng)熱(re)(re)發電行業應(ying)用至(zhi)今已有數十年時間(jian),是當前主流的(de)高(gao)(gao)(gao)溫(wen)儲(chu)(chu)(chu)熱(re)(re)技術。熔(rong)(rong)(rong)(rong)鹽(yan)一(yi)般具有良(liang)好的(de)熱(re)(re)穩定(ding)性(xing)、高(gao)(gao)(gao)潛熱(re)(re)值(zhi)以及(ji)低蒸(zheng)氣壓,相比導熱(re)(re)油、液態金屬(shu)等儲(chu)(chu)(chu)熱(re)(re)介質價格便(bian)宜且儲(chu)(chu)(chu)量豐富。在(zai)(zai)太(tai)陽能(neng)熱(re)(re)發電熔(rong)(rong)(rong)(rong)鹽(yan)系統中(zhong),使用最多的(de)是硝基型的(de)二(er)元熔(rong)(rong)(rong)(rong)鹽(yan),即太(tai)陽鹽(yan)(60%NaNO3+40%KNO3),熔(rong)(rong)(rong)(rong)點220℃,分解(jie)溫(wen)度575℃;化(hua)工領域使用較多的(de)熔(rong)(rong)(rong)(rong)鹽(yan)是三(san)元硝基鹽(yan),即HITEC鹽(yan)(7%NaNO3+53%KNO3+40%NaNO2),熔(rong)(rong)(rong)(rong)點142℃,分解(jie)溫(wen)度450℃。雖(sui)然太(tai)陽能(neng)聚光集熱(re)(re)技術和高(gao)(gao)(gao)溫(wen)熔(rong)(rong)(rong)(rong)鹽(yan)儲(chu)(chu)(chu)熱(re)(re)技術成熟,但單(dan)位投資(zi)較高(gao)(gao)(gao),受當地光資(zi)源影響,在(zai)(zai)新疆(jiang)油田替代(dai)天然氣制蒸(zheng)汽尚存在(zai)(zai)經(jing)濟性(xing)不(bu)佳的(de)問題。以新疆(jiang)油田某井區光熱(re)(re)先導試驗(yan)項目為(wei)例,增加(jia)熔(rong)(rong)(rong)(rong)鹽(yan)儲(chu)(chu)(chu)熱(re)(re)系統測(ce)算(suan)的(de)蒸(zheng)汽成本要比不(bu)帶(dai)儲(chu)(chu)(chu)熱(re)(re)系統的(de)光熱(re)(re)直接(jie)產蒸(zheng)汽系統高(gao)(gao)(gao)100元/t。考慮到陰雨(yu)天影響,要做到連續供(gong)能(neng)須進一(yi)步增加(jia)儲(chu)(chu)(chu)熱(re)(re)規模(mo)。
北疆地(di)區風(feng)(feng)、光(guang)(guang)(guang)可再生能(neng)源(yuan)豐富,新疆油(you)田公司(si)正開(kai)展以風(feng)(feng)電(dian)(dian)、光(guang)(guang)(guang)伏為主體(ti)的(de)新能(neng)源(yuan)發電(dian)(dian)設施建設,可考(kao)慮將生產的(de)綠電(dian)(dian)轉化為熱能(neng)儲(chu)存(cun)在(zai)熔(rong)鹽系統(tong)(tong)中。在(zai)太陽能(neng)聚光(guang)(guang)(guang)集(ji)熱+熔(rong)鹽儲(chu)熱系統(tong)(tong)基礎上增加(jia)熔(rong)鹽電(dian)(dian)加(jia)熱爐,利(li)用白天風(feng)(feng)光(guang)(guang)(guang)棄(qi)電(dian)(dian)和夜(ye)間谷電(dian)(dian)加(jia)熱熔(rong)鹽,合理利(li)用儲(chu)熱系統(tong)(tong)容(rong)量(liang),提升儲(chu)能(neng)規模,在(zai)降低供(gong)汽成(cheng)本的(de)同(tong)時也減少了(le)油(you)區周邊風(feng)(feng)光(guang)(guang)(guang)新能(neng)源(yuan)的(de)棄(qi)電(dian)(dian)。
電(dian)(dian)(dian)加(jia)(jia)熱(re)(re)爐(lu)根(gen)據(ju)加(jia)(jia)熱(re)(re)原理不(bu)同,可(ke)分(fen)為(wei)電(dian)(dian)(dian)阻式(shi)(shi)、電(dian)(dian)(dian)磁式(shi)(shi)和電(dian)(dian)(dian)極式(shi)(shi)等不(bu)同型式(shi)(shi)。電(dian)(dian)(dian)阻式(shi)(shi)加(jia)(jia)熱(re)(re)方式(shi)(shi)采用低電(dian)(dian)(dian)壓輸(shu)入,適用于(yu)單(dan)臺功(gong)(gong)率較小(<3 MW)的(de)(de)電(dian)(dian)(dian)加(jia)(jia)熱(re)(re)爐(lu),在(zai)(zai)加(jia)(jia)熱(re)(re)熔(rong)鹽(yan)過(guo)程中電(dian)(dian)(dian)熱(re)(re)管表(biao)面形成(cheng)的(de)(de)局部(bu)(bu)高(gao)溫(wen)會造成(cheng)熔(rong)鹽(yan)分(fen)解變(bian)性和局部(bu)(bu)傳熱(re)(re)惡化(hua)。電(dian)(dian)(dian)磁式(shi)(shi)加(jia)(jia)熱(re)(re)方式(shi)(shi)存(cun)在(zai)(zai)電(dian)(dian)(dian)轉磁轉熱(re)(re)過(guo)程中有用功(gong)(gong)下降(jiang),整體(ti)能量轉換效(xiao)(xiao)率降(jiang)低的(de)(de)問(wen)題,通常(chang)電(dian)(dian)(dian)磁加(jia)(jia)熱(re)(re)綜(zong)合效(xiao)(xiao)率低于(yu)90%。熔(rong)鹽(yan)電(dian)(dian)(dian)極加(jia)(jia)熱(re)(re)方式(shi)(shi)可(ke)較好地解決電(dian)(dian)(dian)阻式(shi)(shi)與電(dian)(dian)(dian)磁式(shi)(shi)技術在(zai)(zai)大(da)容量熔(rong)鹽(yan)加(jia)(jia)熱(re)(re)中存(cun)在(zai)(zai)的(de)(de)問(wen)題。熔(rong)鹽(yan)本身就是電(dian)(dian)(dian)阻,不(bu)會存(cun)在(zai)(zai)發(fa)熱(re)(re)不(bu)均和局部(bu)(bu)過(guo)熱(re)(re)的(de)(de)情況;電(dian)(dian)(dian)極加(jia)(jia)熱(re)(re)效(xiao)(xiao)率能達到99%以上,輸(shu)入高(gao)電(dian)(dian)(dian)壓提升單(dan)臺功(gong)(gong)率,適合大(da)規模電(dian)(dian)(dian)加(jia)(jia)熱(re)(re)。
《中國(guo)太陽(yang)能熱(re)發(fa)電(dian)(dian)行(xing)業(ye)藍皮(pi)書2022》指出(chu),降低聚光(guang)(guang)(guang)(guang)器(qi)成(cheng)(cheng)本和提(ti)(ti)高聚光(guang)(guang)(guang)(guang)鏡(jing)場效(xiao)率(lv)(lv)一直是推(tui)進太陽(yang)能光(guang)(guang)(guang)(guang)熱(re)發(fa)電(dian)(dian)的(de)(de)重(zhong)大課題。全球太陽(yang)能熱(re)發(fa)電(dian)(dian)的(de)(de)平準化(hua)度電(dian)(dian)成(cheng)(cheng)本(LCOE)從2010年(nian)0.358美(mei)元(yuan)/(kW·h)降低到2020年(nian)0.114美(mei)元(yuan)/(kW·h),十年(nian)下(xia)降70%。該報告預測,到2030年(nian)塔式光(guang)(guang)(guang)(guang)熱(re)電(dian)(dian)站太陽(yang)島成(cheng)(cheng)本將下(xia)降23.1%,年(nian)均成(cheng)(cheng)本下(xia)降率(lv)(lv)3%。聚光(guang)(guang)(guang)(guang)、吸熱(re)及(ji)熱(re)功轉(zhuan)換(huan)過(guo)程(cheng)是構成(cheng)(cheng)系(xi)統(tong)能量和效(xiao)率(lv)(lv)損失的(de)(de)主要部分(fen),約(yue)占總(zong)損失的(de)(de)97%。因此(ci)提(ti)(ti)高太陽(yang)能熱(re)發(fa)電(dian)(dian)效(xiao)率(lv)(lv)的(de)(de)關鍵在(zai)于(yu)提(ti)(ti)高集熱(re)及(ji)熱(re)功轉(zhuan)換(huan)過(guo)程(cheng)的(de)(de)效(xiao)率(lv)(lv)。據保守估計,到2030年(nian)聚光(guang)(guang)(guang)(guang)集熱(re)系(xi)統(tong)光(guang)(guang)(guang)(guang)熱(re)轉(zhuan)換(huan)效(xiao)率(lv)(lv)可提(ti)(ti)升14%,年(nian)均增長(chang)1.9%。具(ju)體體現(xian)在(zai)定日(ri)(ri)鏡(jing)清潔技(ji)(ji)術(shu)(shu)、云預測技(ji)(ji)術(shu)(shu)、定日(ri)(ri)鏡(jing)鏡(jing)面(mian)工(gong)藝(yi)、鏡(jing)場排布工(gong)藝(yi)、截斷效(xiao)率(lv)(lv)優化(hua)以及(ji)吸熱(re)器(qi)涂層等方面(mian)的(de)(de)技(ji)(ji)術(shu)(shu)提(ti)(ti)升與系(xi)統(tong)優化(hua)。受(shou)益于(yu)未來高溫光(guang)(guang)(guang)(guang)熱(re)技(ji)(ji)術(shu)(shu)的(de)(de)提(ti)(ti)升和成(cheng)(cheng)本的(de)(de)下(xia)降,高溫光(guang)(guang)(guang)(guang)熱(re)在(zai)稠(chou)油熱(re)采的(de)(de)應用具(ju)有(you)廣闊的(de)(de)發(fa)展前景。
結(jie)合(he)新疆油(you)田公(gong)司稠油(you)生產規模(mo)以(yi)及未(wei)來開發規劃(hua),依托當地可再(zai)生能源(yuan)稟賦并根(gen)據項目邊界條(tiao)件約束,針對三(san)種不(bu)同稠油(you)開采場(chang)景提出太陽(yang)能光熱(re)供熱(re)解(jie)決方案,在保障(zhang)供能和蒸汽(qi)品質基礎上以(yi)蒸汽(qi)成本(ben)最低為(wei)目標開展(zhan)方案對比(bi)分析。
2、光熱非連續產汽解決方案
稠油熱(re)采工藝主要分為(wei)蒸汽吞吐、蒸汽驅、SAGD和驅泄復(fu)合(he)(VHSD)等(deng)方式,其(qi)基本原理是(shi)通過往(wang)油層(ceng)注入(ru)高干(gan)度(du)或過熱(re)蒸汽加熱(re)油層(ceng),從而降低稠油黏度(du)、增加稠油流動性(xing),以便(bian)于(yu)采油舉升和輸(shu)送。
SAGD開采過程中,主(zhu)要依(yi)靠(kao)濕飽(bao)和蒸汽(qi)(qi)的(de)汽(qi)(qi)化潛(qian)熱(re)加(jia)熱(re)油(you)藏,給原油(you)的(de)熱(re)量傳遞以熱(re)傳導為主(zhu),對流(liu)為輔。開發(fa)至(zhi)一定階段,泄(xie)油(you)后形(xing)成(cheng)的(de)地下(xia)蒸汽(qi)(qi)腔橫向擴(kuo)展,相鄰井間蒸汽(qi)(qi)腔實現(xian)連(lian)通,地下(xia)發(fa)育形(xing)成(cheng)的(de)蒸汽(qi)(qi)腔具有(you)良好儲熱(re)條(tiao)件(jian)。試驗(yan)發(fa)現(xian),當采用變流(liu)量注(zhu)入蒸汽(qi)(qi)時,最終采收(shou)率(lv)、突破時間、產(chan)油(you)高(gao)峰期與持(chi)續穩定注(zhu)汽(qi)(qi)的(de)生(sheng)產(chan)效果幾乎(hu)相同。
采(cai)用(yong)SAGD工藝開發的稠(chou)油作業(ye)區可(ke)采(cai)用(yong)高(gao)溫光(guang)熱(re)直接制(zhi)(zhi)蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)(CS-DSG)系統(tong)(tong)(tong)與注汽(qi)(qi)(qi)(qi)鍋爐耦合(he)運行的方(fang)式開展光(guang)熱(re)制(zhi)(zhi)蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi),通過變流量(liang)注入蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)。為(wei)分(fen)析(xi)(xi)不同(tong)鏡場(chang)(chang)規(gui)模對應(ying)(ying)(ying)的光(guang)熱(re)制(zhi)(zhi)蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)成(cheng)本(ben),分(fen)別(bie)選取20 t/h、36 t/h、66 t/h、200 t/h四(si)種光(guang)熱(re)制(zhi)(zhi)蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)出力方(fang)案開展集熱(re)鏡場(chang)(chang)布(bu)置與系統(tong)(tong)(tong)匹配分(fen)析(xi)(xi)。結果(guo)表(biao)明,隨著(zhu)集熱(re)鏡場(chang)(chang)的規(gui)模增(zeng)加單位投資(zi)成(cheng)本(ben)呈(cheng)現下降(jiang)(jiang)趨勢,成(cheng)本(ben)降(jiang)(jiang)低主要得(de)益于光(guang)熱(re)制(zhi)(zhi)蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)系統(tong)(tong)(tong)的規(gui)模效應(ying)(ying)(ying)。但當鏡場(chang)(chang)規(gui)模增(zeng)長到(dao)一定程度(du),系統(tong)(tong)(tong)光(guang)熱(re)轉化效率(lv)有所(suo)降(jiang)(jiang)低,造成(cheng)集熱(re)量(liang)減(jian)少,蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)產量(liang)也相應(ying)(ying)(ying)減(jian)少,折(zhe)算(suan)全生(sheng)命周期(qi)的噸蒸(zheng)(zheng)汽(qi)(qi)(qi)(qi)投資(zi)成(cheng)本(ben)反而(er)上升。具體方(fang)案參(can)數(shu)對比(bi)見(jian)表(biao)1。
表1不同規模CS-DSG系統參(can)數對比(bi)
表1中方(fang)案三的經濟性最佳(jia),產汽量66 t/h,噸蒸汽成本140元(yuan),每年預計可節省天然氣6.83×106m3,減排(pai)二(er)氧(yang)化(hua)碳1.475×104 t。
為提(ti)高(gao)鏡(jing)場(chang)的光學效率和土地利(li)用率,優化鏡(jing)場(chang)采用非(fei)圓形鏡(jing)場(chang)布置,鏡(jing)場(chang)布置見圖(tu)4。
圖4太陽能集熱鏡(jing)場(chang)布置及(ji)余弦(xian)效率分布
通過(guo)(guo)鏡場布(bu)置(zhi)優(you)化(hua),整體余弦效(xiao)率提升(sheng)至(zhi)79.33%。CS-DSG技術直接(jie)(jie)將太(tai)陽光(guang)(guang)(guang)(guang)輻射熱(re)(re)(re)轉化(hua)為(wei)工質(zhi)的(de)熱(re)(re)(re)能,其光(guang)(guang)(guang)(guang)熱(re)(re)(re)轉化(hua)效(xiao)率要比光(guang)(guang)(guang)(guang)伏(fu)發(fa)(fa)電+電鍋爐制蒸汽(qi)高(gao)很多。對比相近(jin)產汽(qi)量的(de)光(guang)(guang)(guang)(guang)熱(re)(re)(re)制蒸汽(qi)方案與(yu)光(guang)(guang)(guang)(guang)伏(fu)發(fa)(fa)電+電鍋爐方案(表(biao)2)后發(fa)(fa)現:①年(nian)集(ji)熱(re)(re)(re)量相近(jin)、產汽(qi)量接(jie)(jie)近(jin),光(guang)(guang)(guang)(guang)熱(re)(re)(re)鏡場占(zhan)地(di)只有光(guang)(guang)(guang)(guang)伏(fu)陣列(lie)占(zhan)地(di)的(de)1/4;②CS-DSG系統單(dan)位造(zao)價(jia)約為(wei)光(guang)(guang)(guang)(guang)伏(fu)+電鍋爐制汽(qi)系統單(dan)位造(zao)價(jia)的(de)85%;③光(guang)(guang)(guang)(guang)熱(re)(re)(re)轉化(hua)效(xiao)率比光(guang)(guang)(guang)(guang)電轉化(hua)效(xiao)率高(gao)1倍(bei)。以(yi)上差別主要是由于太(tai)陽能光(guang)(guang)(guang)(guang)熱(re)(re)(re)轉化(hua)效(xiao)率可以(yi)達到40%~50%,而太(tai)陽能光(guang)(guang)(guang)(guang)電轉化(hua)效(xiao)率只有20%多;光(guang)(guang)(guang)(guang)伏(fu)發(fa)(fa)電一般采用固定支(zhi)架,為(wei)避(bi)免過(guo)(guo)度遮擋,陣列(lie)間(jian)距較大(da)。
表2 CS-DSG系統與光伏(fu)發電+電鍋爐制蒸汽方案(an)參數對比
綜合上述對比分(fen)析,對于采用(yong)SAGD工藝(yi)且已開發一(yi)段時間的稠油(you)作(zuo)業區,可采用(yong)CS-DSG系統與(yu)現有注汽(qi)鍋(guo)爐耦合運(yun)行,以(yi)較低成本實現可再生能(neng)源替代部分(fen)天然氣。
3、光熱連續產汽解決方案
相比(bi)SAGD工(gong)(gong)藝(yi)(yi)(yi),稠油(you)熱(re)采(cai)的(de)其(qi)它工(gong)(gong)藝(yi)(yi)(yi)對蒸汽(qi)連續穩定性(xing)(xing)要求相對較高,或(huo)需要對現有(you)注汽(qi)鍋(guo)爐實現可再生(sheng)能(neng)源全部替代,該場景下應考慮采(cai)用高溫光(guang)(guang)熱(re)連續制(zhi)(zhi)蒸汽(qi)(CS-SGS)方案(an)。CS-SGS系(xi)(xi)(xi)統(tong)(tong)(tong)包(bao)括聚光(guang)(guang)集熱(re)系(xi)(xi)(xi)統(tong)(tong)(tong)、熔(rong)(rong)鹽工(gong)(gong)質吸熱(re)器、熔(rong)(rong)鹽儲熱(re)系(xi)(xi)(xi)統(tong)(tong)(tong)、熔(rong)(rong)鹽蒸汽(qi)發生(sheng)系(xi)(xi)(xi)統(tong)(tong)(tong)、汽(qi)水系(xi)(xi)(xi)統(tong)(tong)(tong)及(ji)電氣及(ji)熱(re)工(gong)(gong)控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong),相比(bi)CS-DSG增加了(le)熔(rong)(rong)鹽儲熱(re)系(xi)(xi)(xi)統(tong)(tong)(tong)和(he)熔(rong)(rong)鹽蒸汽(qi)發生(sheng)系(xi)(xi)(xi)統(tong)(tong)(tong),這與光(guang)(guang)熱(re)發電前端產汽(qi)系(xi)(xi)(xi)統(tong)(tong)(tong)工(gong)(gong)藝(yi)(yi)(yi)流程一致,運(yun)行穩定性(xing)(xing)與可靠性(xing)(xing)均有(you)保證。主要問題是受制(zhi)(zhi)于油(you)區光(guang)(guang)資源條(tiao)件和(he)光(guang)(guang)熱(re)系(xi)(xi)(xi)統(tong)(tong)(tong)成本,替代經濟性(xing)(xing)不佳。
借鑒(jian)火電(dian)廠和(he)可再生能源大基地(di)的做法(fa),充分(fen)利(li)用谷(gu)電(dian)和(he)風光棄電(dian),把電(dian)能轉化為(wei)熱(re)(re)能存儲在(zai)熔(rong)鹽中。在(zai)集熱(re)(re)鏡(jing)場、熔(rong)鹽儲熱(re)(re)系(xi)統(tong)基礎上增加(jia)電(dian)極加(jia)熱(re)(re)熔(rong)鹽裝置,實現(xian)太陽能集熱(re)(re)系(xi)統(tong)耦合電(dian)極加(jia)熱(re)(re)系(xi)統(tong)對熔(rong)鹽進(jin)行加(jia)熱(re)(re)。充分(fen)利(li)用罐容提高儲熱(re)(re)規模,增加(jia)供(gong)汽規模,利(li)用谷(gu)電(dian)和(he)棄電(dian)也(ye)降低了蒸汽成本(ben)。表3是CS-SGS系(xi)統(tong)與增加(jia)一套40 MW電(dian)熔(rong)鹽加(jia)熱(re)(re)系(xi)統(tong)方案對比(bi)。后(hou)者(zhe)集熱(re)(re)量增加(jia)158%,儲熱(re)(re)系(xi)統(tong)容量由132 MW·h增加(jia)到300 MW·h,對應儲熱(re)(re)時長(chang)(chang)由6 h增長(chang)(chang)到14 h。年產(chan)蒸汽量由每年8.2×104 t增長(chang)(chang)到21.2×104 t,噸蒸汽成本(ben)從(cong)240元降低到174元。
表3 CS-SGS系統增加電熔(rong)鹽加熱器前后參(can)數對比
本(ben)方(fang)案利用(yong)(yong)白天(tian)光熱資源和夜間谷電(dian)(dian)(dian)(dian)資源,在(zai)熔(rong)鹽儲熱系(xi)統(tong)罐容基礎(chu)上(shang)增加一定(ding)儲熱容量,可實現較大規(gui)模的(de)穩(wen)定(ding)供汽,具體耦合配(pei)置方(fang)案可根(gen)據現場(chang)蒸(zheng)汽需(xu)求確定(ding)。當前在(zai)開展光伏、風電(dian)(dian)(dian)(dian)等可再生能源供能設施建設,當風光發(fa)電(dian)(dian)(dian)(dian)發(fa)展到(dao)一定(ding)階段必將面臨(lin)可再生能源電(dian)(dian)(dian)(dian)力(li)(li)消納、電(dian)(dian)(dian)(dian)網調峰和棄(qi)(qi)電(dian)(dian)(dian)(dian)之間的(de)問題。在(zai)開展光熱制蒸(zheng)汽替代天(tian)然氣注汽鍋爐方(fang)案基礎(chu)上(shang)增加電(dian)(dian)(dian)(dian)加熱器配(pei)置,利用(yong)(yong)棄(qi)(qi)電(dian)(dian)(dian)(dian)/谷電(dian)(dian)(dian)(dian)開展熔(rong)鹽儲熱,既解決棄(qi)(qi)電(dian)(dian)(dian)(dian)問題,又(you)得到(dao)油(you)田(tian)作業區需(xu)要的(de)綠色(se)熱能,同時增加用(yong)(yong)戶側(ce)負荷調節能力(li)(li),起到(dao)一舉多(duo)得的(de)作用(yong)(yong)。
4、大規模開發的稠油作業區光熱解決方案
前述兩個方(fang)案主要針(zhen)對已開發的(de)(de)稠油作業(ye)(ye)區(qu)開展(zhan)以(yi)(yi)熱替熱的(de)(de)可(ke)再生能(neng)(neng)源供(gong)能(neng)(neng)替代(dai)。對于大(da)規模新(xin)上(shang)產(chan)能(neng)(neng)的(de)(de)稠油作業(ye)(ye)區(qu),則需要系統性(xing)配置低碳(tan)供(gong)能(neng)(neng)解(jie)決方(fang)案,在保障(zhang)供(gong)能(neng)(neng)的(de)(de)基礎上(shang)做好與新(xin)能(neng)(neng)源的(de)(de)融合(he)發展(zhan),并(bing)兼顧經濟性(xing)要求。為(wei)此(ci)提出光(guang)熱/光(guang)伏(fu)耦合(he)燃機熱電(dian)聯(lian)產(chan)方(fang)案,可(ke)在最大(da)限度上(shang)滿足新(xin)上(shang)產(chan)能(neng)(neng)的(de)(de)作業(ye)(ye)區(qu)清潔用(yong)電(dian)、用(yong)熱的(de)(de)需求。基于以(yi)(yi)下指導原(yuan)則開展(zhan)低碳(tan)供(gong)能(neng)(neng)方(fang)案的(de)(de)配置。
①同一地區光(guang)資源(yuan)的變(bian)化情況與光(guang)熱制蒸汽與光(guang)伏發電出力(li)變(bian)化曲線基本一致。
②燃機(ji)熱(re)(re)電聯產技術成熟,屬(shu)于清潔供能,其供熱(re)(re)與發(fa)電出力隨(sui)燃機(ji)負荷變(bian)化可同(tong)步快速(su)調整。
③耦合光(guang)熱(re)(re)(re)、光(guang)伏與燃(ran)(ran)機(ji)實現熱(re)(re)(re)電(dian)(dian)聯(lian)產(chan)匹配。白天通(tong)過太(tai)陽能(neng)為(wei)油田提供無碳(tan)蒸汽與電(dian)(dian)力,燃(ran)(ran)機(ji)熱(re)(re)(re)電(dian)(dian)聯(lian)產(chan)機(ji)組作為(wei)調峰(feng)以及夜間基(ji)荷(he)供應(ying),削峰(feng)填谷起到可再生能(neng)源的壓艙石作用。
太(tai)陽能(neng)、天然氣、風(feng)能(neng)等一次(ci)能(neng)源(yuan)目前主要(yao)(yao)是通過(guo)高(gao)溫(wen)(wen)光熱、燃機熱電聯產、光伏(fu)(fu)發(fa)(fa)電、風(feng)力發(fa)(fa)電等技術轉(zhuan)換為二次(ci)能(neng)源(yuan)(如蒸(zheng)汽(qi)和(he)電力等)加以利用(yong),轉(zhuan)換流(liu)程見圖5。稠油(you)開發(fa)(fa)的主要(yao)(yao)用(yong)能(neng)為蒸(zheng)汽(qi)和(he)電力,因(yin)此,可以考(kao)慮(lv)耦合高(gao)溫(wen)(wen)光熱制蒸(zheng)汽(qi)、光伏(fu)(fu)發(fa)(fa)電和(he)燃機熱電聯產等技術,通過(guo)多能(neng)互補(bu)的形式為稠油(you)開發(fa)(fa)提供(gong)蒸(zheng)汽(qi)和(he)電力。
圖5太陽能光(guang)(guang)熱/光(guang)(guang)伏耦合燃(ran)機實現熱電聯(lian)產
新疆油(you)田公司擬開(kai)發(fa)的某稠油(you)作業(ye)區采(cai)取太陽,基本運行模式如下。
①白(bai)天光熱制(zhi)蒸汽系統(tong)高負(fu)荷(he)運行,燃(ran)機可采取一(yi)臺運行、一(yi)臺備用的模式。
②當光熱制蒸汽(qi)系統轉為(wei)低負荷或停運時,通過增(zeng)加(jia)燃機(ji)(ji)出(chu)力或啟動另一臺燃機(ji)(ji)提升供汽(qi)能(neng)力。
③燃機采(cai)取(qu)以(yi)熱定電(dian)的運(yun)行方式,耦合光熱制蒸(zheng)汽(qi)系統為(wei)作業區提供(gong)所需蒸(zheng)汽(qi),作為(wei)供(gong)汽(qi)調峰(feng),同時兼(jian)顧(gu)電(dian)網調峰(feng)。
通過以充分(fen)利(li)用(yong)太(tai)陽能且(qie)整體供汽(qi)量(liang)保(bao)持穩定為目(mu)標(biao)的系(xi)統(tong)優化,配置(zhi)了太(tai)陽能光熱+燃機熱電聯產(chan)耦合供汽(qi)的供能設(she)施(shi)參(can)數(shu),見表4。
表4光(guang)熱/光(guang)伏耦合燃機熱電聯產配置方案
通過(guo)光熱/光伏耦(ou)合燃(ran)(ran)機(ji)熱電聯產方(fang)式,實(shi)(shi)現了對(dui)稠油作業(ye)區(qu)大規模可靠(kao)的(de)供(gong)能,在維持(chi)現有供(gong)汽(qi)成本的(de)前提(ti)下提(ti)升供(gong)能設施的(de)清潔性并與新能源有效融合。方(fang)案(an)配置(zhi)可根(gen)據蒸汽(qi)電力需(xu)求(qiu)靈(ling)活耦(ou)合熔鹽電加熱裝置(zhi),配置(zhi)熔鹽儲(chu)熱方(fang)式,根(gen)據供(gong)能規模配置(zhi)不同規模、數(shu)量(liang)的(de)燃(ran)(ran)機(ji)。例(li)如對(dui)于蒸汽(qi)需(xu)求(qiu)在150~200 t/h的(de)作業(ye)區(qu),可配置(zhi)1臺套(tao)燃(ran)(ran)機(ji)熱電聯產系統(tong),1套(tao)44 MW的(de)CS-DSG系統(tong),或者1~2套(tao)耦(ou)合電熔鹽加熱器的(de)CS-SGS系統(tong);對(dui)于100~150 t/h蒸汽(qi)需(xu)求(qiu)的(de)作業(ye)區(qu),采取小規模的(de)燃(ran)(ran)機(ji)配置(zhi)實(shi)(shi)現熱電匹配。
5、結論與建議
光熱(re)(re)(re)在稠油熱(re)(re)(re)采中的(de)應用是利用高(gao)溫太(tai)陽能(neng)聚光集(ji)熱(re)(re)(re)技術將(jiang)太(tai)陽能(neng)轉化為熱(re)(re)(re)能(neng),替代燃燒煤炭、天(tian)然氣生產高(gao)品質蒸汽,用于稠油熱(re)(re)(re)采注(zhu)汽,實現稠油蒸汽驅油的(de)可再生能(neng)源(yuan)替代。
1)對于已開(kai)發區(qu)塊特別是(shi)采用(yong)SAGD開(kai)發方(fang)式(shi)的(de)稠(chou)油作(zuo)業區(qu),利(li)用(yong)形(xing)成地下(xia)汽(qi)腔的(de)儲熱(re)能力,現階段優先考慮采用(yong)CS-DSG技術,耦合現有注汽(qi)鍋爐聯(lian)合供汽(qi),井口變流量注汽(qi)方(fang)式(shi)。
2)對(dui)于蒸汽(qi)驅或蒸汽(qi)吞(tun)吐開(kai)發方(fang)式的(de)稠油(you)作業區,依托周邊風電(dian)(dian)光伏產生的(de)綠電(dian)(dian)、棄電(dian)(dian)以(yi)及谷電(dian)(dian)資源,采(cai)用CS-SGS技術,耦合高溫聚(ju)光集熱與電(dian)(dian)加熱,匹配熔鹽儲熱系統生產蒸汽(qi),在降(jiang)低蒸汽(qi)成(cheng)本基礎上(shang)實(shi)現可再生能源連續為稠油(you)開(kai)采(cai)提供蒸汽(qi)。
3)對(dui)于新(xin)上產能(neng)稠油(you)(you)(you)作業區,結合國家對(dui)建設油(you)(you)(you)氣與太(tai)陽能(neng)同(tong)步開發綜合利(li)用示范工程的(de)要求及新(xin)疆(jiang)油(you)(you)(you)田(tian)上產規劃,利(li)用光(guang)(guang)熱制蒸(zheng)汽(qi)+光(guang)(guang)伏發電耦合燃(ran)機(ji)熱電聯產的(de)方式(shi)為(wei)油(you)(you)(you)田(tian)提(ti)供(gong)綠色(se)、清潔(jie)、低碳的(de)蒸(zheng)汽(qi)與電力(li)供(gong)應。
4)光熱(re)(re)制(zhi)(zhi)蒸汽成(cheng)本已經接近(jin)傳統(tong)(tong)燃氣注汽鍋爐的(de)蒸汽成(cheng)本,隨著光熱(re)(re)制(zhi)(zhi)蒸汽系(xi)統(tong)(tong)成(cheng)本降低與(yu)技術進步,預(yu)計未(wei)來3~5年(nian)光熱(re)(re)制(zhi)(zhi)蒸汽成(cheng)本將(jiang)與(yu)天然氣注汽鍋爐制(zhi)(zhi)汽成(cheng)本持平,光熱(re)(re)制(zhi)(zhi)蒸汽在稠油熱(re)(re)采中(zhong)的(de)應(ying)用(yong)具(ju)有廣闊的(de)發展前景(jing)。