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摘要：儲能是新型電力系統的關鍵核心技術，熔鹽儲能作為一種中高溫傳熱蓄熱方法，因具有儲能密度高、穩定性好等優點，廣泛應用于太陽能光熱系統、調峰調頻、綠電消納等新能源領域。但目前對熔鹽儲能系統中的核心部件如儲罐、熔鹽電加熱器、熔鹽換熱器等設備的研究普遍基于太陽能熱發電技術的需求開展，針對其他應用場景的研究尚不夠充分。在不同應用場景下，熔鹽的使用溫度區間、加熱及換熱方式都有區別。概述了熔鹽儲能關鍵技術的研究現狀和技術成果，研究了熔鹽儲能技術的發展路徑，提出了其在新型電力系統中的應用領域，并針對不同應用場景，提出了相應的熔鹽選型參數、儲罐及換熱器類型。

引言：“雙(shuang)碳(tan)”背景(jing)下，構建新(xin)(xin)型電(dian)(dian)力系統是保(bao)障我(wo)國能(neng)(neng)源安(an)全的(de)戰略任務。光伏(fu)光熱(re)(re)、風電(dian)(dian)水(shui)力等新(xin)(xin)能(neng)(neng)源存(cun)在間歇性和(he)(he)不穩定性，易造成(cheng)能(neng)(neng)源供(gong)需(xu)(xu)不匹(pi)配(pei)，需(xu)(xu)要配(pei)合儲(chu)能(neng)(neng)技(ji)(ji)術(shu)。熔(rong)鹽(yan)儲(chu)熱(re)(re)是一種安(an)全水(shui)平較高的(de)儲(chu)能(neng)(neng)方式，利用(yong)硝酸鹽(yan)等熔(rong)鹽(yan)作為傳熱(re)(re)介質，通過熔(rong)鹽(yan)的(de)儲(chu)熱(re)(re)和(he)(he)放熱(re)(re)循(xun)環來存(cun)儲(chu)和(he)(he)放出能(neng)(neng)量(liang)，實現能(neng)(neng)量(liang)的(de)有效遷移。熔(rong)鹽(yan)儲(chu)能(neng)(neng)的(de)關(guan)鍵核(he)心(xin)技(ji)(ji)術(shu)和(he)(he)設備包括熔(rong)鹽(yan)、電(dian)(dian)加熱(re)(re)器、儲(chu)罐以(yi)及換熱(re)(re)器等，廣(guang)泛應(ying)用(yong)在以(yi)下3個方向：太陽(yang)能(neng)(neng)光熱(re)(re)發(fa)電(dian)(dian)、耦(ou)合火電(dian)(dian)機(ji)組調(diao)峰調(diao)頻、耦(ou)合新(xin)(xin)能(neng)(neng)源綠(lv)電(dian)(dian)供(gong)熱(re)(re)。表1為熔(rong)鹽(yan)儲(chu)能(neng)(neng)不同應(ying)用(yong)場景(jing)對(dui)比。針對(dui)不同應(ying)用(yong)場景(jing)，熔(rong)鹽(yan)的(de)使用(yong)溫度區間和(he)(he)換熱(re)(re)過程(cheng)均有較大差(cha)異。現階段以(yi)解決光熱(re)(re)電(dian)(dian)站(zhan)的(de)技(ji)(ji)術(shu)需(xu)(xu)求為主，針對(dui)熔(rong)鹽(yan)儲(chu)能(neng)(neng)耦(ou)合火電(dian)(dian)機(ji)組調(diao)峰調(diao)頻、綠(lv)電(dian)(dian)供(gong)熱(re)(re)等領域的(de)系統性研究嚴重(zhong)不足。

1、熔鹽儲能關鍵技術

現有熔鹽(yan)的(de)(de)選型主(zhu)要為耐(nai)高(gao)溫熔鹽(yan)和低(di)熔點鹽(yan)。耐(nai)高(gao)溫熔鹽(yan)如(ru)(ru)技術成熟的(de)(de)Solar鹽(yan)，最(zui)高(gao)工作溫度(du)達565℃，適(shi)合于高(gao)參數光熱(re)發電(dian)或火電(dian)機組儲(chu)熱(re)調峰(feng)系統(tong)。低(di)熔點鹽(yan)通常為多元(yuan)混(hun)合鹽(yan)，熔點低(di)于240℃，如(ru)(ru)工程(cheng)中常用(yong)的(de)(de)Hitec鹽(yan)等，能降低(di)熔鹽(yan)凝固的(de)(de)風險(xian)，適(shi)用(yong)于較低(di)參數的(de)(de)系統(tong)。

熔鹽儲罐主要有單罐、雙罐、多罐系統。單罐熔鹽儲能系統結構簡單，成本較低，適用于小面積生活供暖等領域，但存在斜溫層導致蓄熱效率降低的問題[1]。雙罐系統包含冷罐與熱罐，通過冷熱熔鹽分離并在2罐中循環換熱，避免了斜溫層問題，技術風險也相對較低。在雙罐的基礎上還可進一步增加儲罐數量，形成多罐系統，增大儲熱量。如哈密50 MW熔鹽塔式光熱發電項目(mu)首(shou)創(chuang)了(le)雙熱罐、一冷罐的系統配置，提高(gao)了(le)機組的可靠性和靈活性。

實現大規模熔鹽儲能的關鍵是兼具低成本、可實施性的高電壓等級熔鹽電加熱器的研發。目前，熔鹽電加熱器主要有電阻式、電極式、感應式3種形式。現有技術普遍為380 V或690 V的低壓電阻式加熱器，主要應用于光熱發電場景。若用于電加熱熔鹽的場景如綠電供熱，則存在高壓綠電輸入與低壓加熱器不匹配而產生較高變電成本的問題。目前，市面上總體缺乏成熟的高電壓熔鹽加熱器。

傳(chuan)統的(de)熔(rong)鹽(yan)(yan)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器有(you)管(guan)殼式(shi)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器和套(tao)(tao)管(guan)式(shi)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器。管(guan)殼式(shi)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器是目前熔(rong)鹽(yan)(yan)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器的(de)主要形式(shi)，許多研究(jiu)者(zhe)已通(tong)過實(shi)驗(yan)和計算(suan)給(gei)出(chu)了推薦(jian)的(de)管(guan)程(cheng)、殼程(cheng)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)關(guan)聯式(shi)[2-3]，對其傳(chuan)熱(re)(re)(re)(re)(re)(re)特(te)性進(jin)行(xing)了數學(xue)描(miao)述。套(tao)(tao)管(guan)式(shi)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器具有(you)結構簡單、能(neng)耐高壓的(de)優點，在工程(cheng)中也有(you)應用(yong)。與上(shang)述傳(chuan)統換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器相比，以(yi)印刷(shua)電路板換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器為代表(biao)的(de)緊湊式(shi)換(huan)(huan)(huan)熱(re)(re)(re)(re)(re)(re)器效率高且能(neng)承受高溫、高壓工況，在新(xin)型(xing)電力系統如熔(rong)鹽(yan)(yan)儲能(neng)與新(xin)型(xing)動力循環的(de)耦合中具有(you)很大優勢[4]。表(biao)2整理了熔(rong)鹽(yan)(yan)關(guan)鍵技(ji)術的(de)對比、分(fen)類情(qing)況，以(yi)及(ji)不同的(de)應用(yong)場景下熔(rong)鹽(yan)(yan)、儲罐、加(jia)熱(re)(re)(re)(re)(re)(re)器選型(xing)的(de)區別。

2、熔鹽儲能在光熱領域的應用

太(tai)(tai)陽(yang)能(neng)(neng)光熱(re)(re)發(fa)電是新型電力(li)系統的(de)中(zhong)堅力(li)量，擁有并(bing)網無障礙、連續發(fa)電調節(jie)能(neng)(neng)力(li)強的(de)優勢。光熱(re)(re)電站將太(tai)(tai)陽(yang)能(neng)(neng)以熱(re)(re)能(neng)(neng)的(de)形式存儲在熔鹽(yan)中(zhong)，后續利用熔鹽(yan)加(jia)熱(re)(re)給水獲取蒸汽，優勢在于(yu)儲能(neng)(neng)容量大，對(dui)地理(li)環境要求低(di)(di)，建設(she)規模可達10 GW以上。光熱(re)(re)型熔鹽(yan)儲能(neng)(neng)電站的(de)技術研究重點(dian)是如何(he)降低(di)(di)其成本(ben)、提高安全性。

大(da)部分(fen)光熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)電站(zhan)(zhan)使用熔(rong)(rong)(rong)鹽(yan)(yan)(yan)雙(shuang)罐(guan)(guan)系統(tong)，光熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)和(he)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)的(de)耦合(he)形式分(fen)為(wei)間(jian)(jian)接和(he)直(zhi)接2種。雙(shuang)罐(guan)(guan)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)儲熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)系統(tong)如圖1所示[16-17]。間(jian)(jian)接蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)系統(tong)需(xu)要(yao)換(huan)(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)裝置(zhi)來傳遞熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)量，采(cai)用導(dao)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)油(you)或水(shui)蒸(zheng)(zheng)氣作(zuo)為(wei)傳熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)流體，在(zai)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)中(zhong)蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)。間(jian)(jian)接蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)系統(tong)換(huan)(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)過程為(wei)太陽(yang)能(neng)-熔(rong)(rong)(rong)鹽(yan)(yan)(yan)-導(dao)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)油(you)-蒸(zheng)(zheng)汽(qi)(qi)，熔(rong)(rong)(rong)鹽(yan)(yan)(yan)中(zhong)儲存的(de)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)能(neng)通過導(dao)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)油(you)循環(huan)，到達蒸(zheng)(zheng)汽(qi)(qi)發生器(qi)換(huan)(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)。間(jian)(jian)接蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)系統(tong)中(zhong)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)儲能(neng)系統(tong)作(zuo)為(wei)相對獨立的(de)模塊存在(zai)，可用于改造普通光熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)電站(zhan)(zhan)。因導(dao)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)油(you)的(de)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)穩定(ding)性不(bu)足(zu)，間(jian)(jian)接蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)的(de)工(gong)作(zuo)溫度(du)一般(ban)規定(ding)在(zai)400℃以下(xia)。直(zhi)接蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)系統(tong)采(cai)用熔(rong)(rong)(rong)鹽(yan)(yan)(yan)作(zuo)為(wei)傳熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)和(he)蓄熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)介質，其換(huan)(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)過程為(wei)太陽(yang)能(neng)-熔(rong)(rong)(rong)鹽(yan)(yan)(yan)-蒸(zheng)(zheng)汽(qi)(qi)，不(bu)需(xu)要(yao)經過導(dao)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)油(you)循環(huan)，避免了不(bu)良(liang)換(huan)(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)(re)，適(shi)用于400～500℃的(de)高溫工(gong)況，也可提高電站(zhan)(zhan)效率和(he)朗肯循環(huan)效率。

光(guang)熱(re)與(yu)(yu)熔(rong)(rong)鹽(yan)(yan)(yan)耦合的(de)(de)2種形式在工程中均有應用(yong)。熔(rong)(rong)鹽(yan)(yan)(yan)間接(jie)(jie)蓄(xu)熱(re)一(yi)般能保持較高的(de)(de)循環效(xiao)率，比蒸汽(qi)蓄(xu)能成(cheng)本更(geng)低[16]，如西班牙Andasol槽式光(guang)熱(re)電(dian)站是第一(yi)個大規模熔(rong)(rong)鹽(yan)(yan)(yan)間接(jie)(jie)蓄(xu)熱(re)電(dian)站，容量(liang)約(yue)為1000 MW·h，儲能時間為7.5 h。熔(rong)(rong)鹽(yan)(yan)(yan)直(zhi)接(jie)(jie)蓄(xu)熱(re)簡化了電(dian)站設(she)備(bei)組成(cheng)，后期運維便捷。典型的(de)(de)熔(rong)(rong)鹽(yan)(yan)(yan)直(zhi)接(jie)(jie)蓄(xu)熱(re)電(dian)站是美國Solar two項(xiang)目，該項(xiang)目使用(yong)的(de)(de)硝酸(suan)鹽(yan)(yan)(yan)混合鹽(yan)(yan)(yan)被(bei)稱作Solar鹽(yan)(yan)(yan)，溫度范圍290~565℃。此后的(de)(de)塔(ta)式熔(rong)(rong)鹽(yan)(yan)(yan)光(guang)熱(re)電(dian)站多沿(yan)用(yong)直(zhi)接(jie)(jie)蓄(xu)熱(re)方(fang)式與(yu)(yu)此工作溫度區間，如西班牙Gemasolar電(dian)廠、青海(hai)中控德令哈10 MW項(xiang)目。

未來(lai)光熱(re)(re)(re)(re)(re)的(de)發展主(zhu)要(yao)(yao)在(zai)(zai)于高(gao)(gao)(gao)參(can)(can)數運行(xing)及(ji)耦合(he)新(xin)型動力(li)循(xun)環(huan)。高(gao)(gao)(gao)參(can)(can)數運行(xing)涉及(ji)的(de)關(guan)鍵技術為耐(nai)高(gao)(gao)(gao)溫(wen)熔(rong)(rong)(rong)鹽(yan)(yan)，選用(yong)碳酸鹽(yan)(yan)和(he)部分(fen)MgCl2-KCl-NaCl混合(he)體系的(de)氯化鹽(yan)(yan)可提(ti)高(gao)(gao)(gao)系統(tong)的(de)整體效(xiao)率(lv)。光熱(re)(re)(re)(re)(re)耦合(he)新(xin)型動力(li)循(xun)環(huan)則主(zhu)要(yao)(yao)及(ji)高(gao)(gao)(gao)參(can)(can)數熔(rong)(rong)(rong)鹽(yan)(yan)及(ji)熔(rong)(rong)(rong)鹽(yan)(yan)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)，以超臨界CO2（S-CO2）布雷頓循(xun)環(huan)光熱(re)(re)(re)(re)(re)發電(dian)(dian)系統(tong)為例，其中(zhong)最高(gao)(gao)(gao)工作溫(wen)度(du)(du)(du)可達800℃，冷熱(re)(re)(re)(re)(re)罐熔(rong)(rong)(rong)鹽(yan)(yan)的(de)溫(wen)差將達到100~120℃，儲(chu)能(neng)(neng)的(de)難度(du)(du)(du)更(geng)大[18]，需要(yao)(yao)使(shi)用(yong)性能(neng)(neng)穩定(ding)的(de)寬溫(wen)域(yu)高(gao)(gao)(gao)參(can)(can)數熔(rong)(rong)(rong)鹽(yan)(yan)。該系統(tong)參(can)(can)數高(gao)(gao)(gao)、效(xiao)率(lv)高(gao)(gao)(gao)、部件緊湊，涉及(ji)的(de)熔(rong)(rong)(rong)鹽(yan)(yan)-CO2換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)需耐(nai)受(shou)苛刻(ke)工況(kuang)。在(zai)(zai)熔(rong)(rong)(rong)鹽(yan)(yan)-CO2換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)領域(yu)可選擇緊湊式換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)如印刷(shua)電(dian)(dian)路板(ban)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)[4]，換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)效(xiao)率(lv)高(gao)(gao)(gao)，能(neng)(neng)承受(shou)高(gao)(gao)(gao)達30 MPa的(de)高(gao)(gao)(gao)溫(wen)、高(gao)(gao)(gao)壓(ya)工況(kuang)。印刷(shua)電(dian)(dian)路板(ban)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)用(yong)于熔(rong)(rong)(rong)鹽(yan)(yan)儲(chu)能(neng)(neng)和(he)CO2循(xun)環(huan)已有研(yan)究。Wang等人[15]設計(ji)并制造了(le)(le)一種翼(yi)形(xing)肋片(pian)印刷(shua)電(dian)(dian)路板(ban)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)，在(zai)(zai)工作壓(ya)力(li)較(jiao)小的(de)熔(rong)(rong)(rong)鹽(yan)(yan)系統(tong)中(zhong)采用(yong)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)性能(neng)(neng)較(jiao)好的(de)肋片(pian)強(qiang)化換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)通(tong)道。張虎忠(zhong)[19]搭建了(le)(le)最高(gao)(gao)(gao)壓(ya)力(li)和(he)溫(wen)度(du)(du)(du)分(fen)別為32 MPa和(he)600℃的(de)S-CO2換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)試驗平(ping)臺，深度(du)(du)(du)掌握(wo)了(le)(le)S-CO2在(zai)(zai)印刷(shua)電(dian)(dian)路板(ban)換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)器(qi)(qi)(qi)(qi)中(zhong)的(de)流(liu)動換(huan)(huan)(huan)(huan)(huan)(huan)熱(re)(re)(re)(re)(re)特性。

光熱(re)(re)發(fa)電中，塔式通(tong)過吸(xi)熱(re)(re)塔吸(xi)收聚集(ji)的(de)太陽能，傳熱(re)(re)至(zhi)熱(re)(re)罐(guan)；槽式通(tong)過集(ji)熱(re)(re)管收集(ji)太陽能；線性菲涅爾式光熱(re)(re)發(fa)電成本(ben)低(di)，在我國西(xi)部擁有(you)良好的(de)商業(ye)化(hua)前景；S-CO2用于光熱(re)(re)系統具有(you)循環(huan)效率高、結(jie)構緊湊的(de)優勢。光熱(re)(re)發(fa)電加熱(re)(re)器一般(ban)為低(di)壓電阻式，以較低(di)的(de)成本(ben)滿足需求(qiu)。除(chu)加熱(re)(re)器外(wai)，不(bu)同(tong)技術路(lu)線涉及的(de)熔(rong)鹽儲能技術存在的(de)區別見(jian)表(biao)3。

3、熔鹽儲能在火電調峰領域的應用

在(zai)火(huo)(huo)電(dian)(dian)(dian)機組中采用(yong)儲(chu)能(neng)可以(yi)實(shi)(shi)(shi)現削峰填(tian)谷，目(mu)前已經(jing)可以(yi)實(shi)(shi)(shi)現工程應用(yong)的是高溫(wen)熔鹽(yan)(yan)(yan)儲(chu)熱耦(ou)(ou)合(he)(he)火(huo)(huo)電(dian)(dian)(dian)機組調(diao)峰技術[20]。熔鹽(yan)(yan)(yan)-火(huo)(huo)電(dian)(dian)(dian)耦(ou)(ou)合(he)(he)系統的優(you)勢在(zai)于(yu)能(neng)極大地提高機組深度調(diao)峰和(he)提供高溫(wen)蒸(zheng)汽(qi)的能(neng)力。熔鹽(yan)(yan)(yan)-火(huo)(huo)電(dian)(dian)(dian)耦(ou)(ou)合(he)(he)形式(shi)多樣，如(ru)抽取部分主蒸(zheng)汽(qi)和(he)再熱蒸(zheng)汽(qi)進入熔鹽(yan)(yan)(yan)儲(chu)能(neng)模塊實(shi)(shi)(shi)現蒸(zheng)汽(qi)蓄熱；用(yong)發電(dian)(dian)(dian)機出(chu)口電(dian)(dian)(dian)力加(jia)熱熔鹽(yan)(yan)(yan)的電(dian)(dian)(dian)加(jia)熱；通過(guo)煙(yan)氣(qi)-熔鹽(yan)(yan)(yan)換熱器實(shi)(shi)(shi)現的煙(yan)氣(qi)蓄熱以(yi)及(ji)(ji)結合(he)(he)以(yi)上幾種耦(ou)(ou)合(he)(he)形式(shi)的混合(he)(he)型加(jia)熱。為提高熔鹽(yan)(yan)(yan)-蒸(zheng)汽(qi)換熱效率、增加(jia)儲(chu)能(neng)時長，火(huo)(huo)電(dian)(dian)(dian)調(diao)峰領域(yu)主要涉(she)及(ji)(ji)高參數、寬溫(wen)域(yu)的熔鹽(yan)(yan)(yan)選型以(yi)及(ji)(ji)安全穩(wen)定(ding)的雙罐熔鹽(yan)(yan)(yan)系統。

3.1蒸汽蓄熱

3.1.1再(zai)熱(re)蒸汽加熱(re)熔(rong)鹽

在火(huo)電機組(zu)(zu)正常運(yun)行的同時抽取高壓主蒸汽(qi)和再熱(re)(re)蒸汽(qi)加熱(re)(re)熔鹽(yan)，該耦合系統(tong)能(neng)夠提高調峰性能(neng)和全過(guo)程循環效率(lv)，主要適用(yong)于亞臨界一次再熱(re)(re)機組(zu)(zu)500~600℃水平的蒸汽(qi)蓄熱(re)(re)。羅海華(hua)等(deng)[21]通過(guo)計(ji)算證明了再熱(re)(re)蒸汽(qi)加熱(re)(re)熔鹽(yan)方案的可行性，該方案利用(yong)熔鹽(yan)存儲的熱(re)(re)量加熱(re)(re)給水，輸出工業蒸汽(qi)，能(neng)實現(xian)火(huo)電機組(zu)(zu)熱(re)(re)電解耦和供熱(re)(re)調峰。熔鹽(yan)-火(huo)電耦合也可存在多(duo)(duo)個抽汽(qi)點，范慶偉(wei)等(deng)[10]以600 MW機組(zu)(zu)為例(li)，提出多(duo)(duo)罐(guan)-多(duo)(duo)換熱(re)(re)器儲熱(re)(re)系統(tong)，將(jiang)再熱(re)(re)蒸汽(qi)分別引入(ru)2個加熱(re)(re)器，其(qi)中疏(shu)水段加熱(re)(re)器的?效率(lv)最高。

3.1.2再熱+過(guo)熱蒸汽加熱熔鹽

同時抽取(qu)再熱(re)(re)、過(guo)(guo)熱(re)(re)蒸汽與熔(rong)鹽換熱(re)(re)的(de)技術(shu)路(lu)(lu)線能夠充分利用鍋(guo)爐(lu)所(suo)產(chan)生(sheng)的(de)高(gao)溫蒸汽，適用主蒸汽溫度為(wei)500～600℃。王輝等[22]設計了火(huo)電(dian)機組超臨界百兆瓦(wa)級熔(rong)鹽儲能工(gong)藝(yi)流(liu)程(cheng)，具體流(liu)程(cheng)如(ru)圖2所(suo)示。其中，冷罐(guan)(guan)熔(rong)鹽預熱(re)(re)后分成2路(lu)(lu)，分別進入過(guo)(guo)熱(re)(re)加熱(re)(re)器(qi)(qi)和(he)(he)再熱(re)(re)加熱(re)(re)器(qi)(qi)，2路(lu)(lu)混合后進入熱(re)(re)鹽罐(guan)(guan)，實現熔(rong)鹽回路(lu)(lu)的(de)流(liu)動儲熱(re)(re)。該方案各工(gong)藝(yi)模(mo)塊(kuai)均為(wei)閉式(shi)循環，在(zai)全過(guo)(guo)程(cheng)中鍋(guo)爐(lu)和(he)(he)汽輪(lun)機的(de)高(gao)溫工(gong)質沒(mei)有減(jian)少或浪費，能極大提高(gao)深度調峰能力和(he)(he)系統(tong)靈(ling)活性(xing)[23]。

3.1.3高再冷(leng)段蒸汽加熱熔鹽

抽取(qu)再(zai)(zai)(zai)(zai)熱(re)(re)蒸(zheng)(zheng)汽(qi)(qi)加熱(re)(re)熔鹽(yan)(yan)可(ke)能(neng)導致再(zai)(zai)(zai)(zai)熱(re)(re)溫度超限(xian)，采用(yong)具有煙氣再(zai)(zai)(zai)(zai)循環(huan)的二(er)(er)次(ci)(ci)(ci)再(zai)(zai)(zai)(zai)熱(re)(re)機(ji)(ji)(ji)組(zu)(zu)可(ke)避免上(shang)述問題(ti)。該技術路線適用(yong)于(yu)主(zhu)蒸(zheng)(zheng)汽(qi)(qi)溫度600～620℃的二(er)(er)次(ci)(ci)(ci)再(zai)(zai)(zai)(zai)熱(re)(re)機(ji)(ji)(ji)組(zu)(zu)。在上(shang)述機(ji)(ji)(ji)組(zu)(zu)中抽取(qu)高(gao)再(zai)(zai)(zai)(zai)冷段(duan)蒸(zheng)(zheng)汽(qi)(qi)加熱(re)(re)熔鹽(yan)(yan)，所儲熱(re)(re)能(neng)可(ke)用(yong)于(yu)加熱(re)(re)給水，供熱(re)(re)或供工業蒸(zheng)(zheng)汽(qi)(qi)，提高(gao)機(ji)(ji)(ji)組(zu)(zu)靈活性。張(zhang)世(shi)剛[24]以某超超臨界660 MW二(er)(er)次(ci)(ci)(ci)再(zai)(zai)(zai)(zai)熱(re)(re)機(ji)(ji)(ji)組(zu)(zu)為(wei)研究對象，提出同(tong)時抽取(qu)一次(ci)(ci)(ci)和二(er)(er)次(ci)(ci)(ci)高(gao)再(zai)(zai)(zai)(zai)冷段(duan)高(gao)溫蒸(zheng)(zheng)汽(qi)(qi)進行熔鹽(yan)(yan)蓄熱(re)(re)。龐力(li)平等(deng)[25]則模擬(ni)了二(er)(er)次(ci)(ci)(ci)再(zai)(zai)(zai)(zai)熱(re)(re)機(ji)(ji)(ji)組(zu)(zu)鍋爐和汽(qi)(qi)輪機(ji)(ji)(ji)的負(fu)荷響應特(te)性，結果表明高(gao)再(zai)(zai)(zai)(zai)冷段(duan)蒸(zheng)(zheng)汽(qi)(qi)用(yong)于(yu)熔鹽(yan)(yan)蓄熱(re)(re)，可(ke)提高(gao)二(er)(er)次(ci)(ci)(ci)再(zai)(zai)(zai)(zai)熱(re)(re)機(ji)(ji)(ji)組(zu)(zu)對電網負(fu)荷的響應速率。

3.1.4直接蒸汽蓄熱(re)技術

針對超超臨界機組620℃以上的(de)(de)蒸(zheng)汽(qi)蓄熱(re)(re)，就需要采(cai)用(yong)(yong)(yong)直接蒸(zheng)汽(qi)蓄熱(re)(re)（direct steam generation，DSG）技術。DSG電站中(zhong)僅產出飽和蒸(zheng)汽(qi)，無法(fa)采(cai)用(yong)(yong)(yong)常規的(de)(de)熔(rong)(rong)鹽(yan)(yan)(yan)冷(leng)、熱(re)(re)罐(guan)(guan)(guan)倒換運行(xing)模式，缺乏合適(shi)的(de)(de)長時(shi)間大(da)規模儲(chu)熱(re)(re)系(xi)統(tong)。為(wei)解決DSG技術的(de)(de)瓶頸，可采(cai)用(yong)(yong)(yong)高(gao)(gao)參數熔(rong)(rong)鹽(yan)(yan)(yan)技術和多罐(guan)(guan)(guan)熔(rong)(rong)鹽(yan)(yan)(yan)系(xi)統(tong)來組成DSG的(de)(de)儲(chu)能裝置(zhi)。如Seitz等人[26]在DSG系(xi)統(tong)中(zhong)耦合冷(leng)、熱(re)(re)、中(zhong)間罐(guan)(guan)(guan)3罐(guan)(guan)(guan)熔(rong)(rong)鹽(yan)(yan)(yan)儲(chu)能，間接存(cun)儲(chu)給水蒸(zheng)發的(de)(de)熱(re)(re)量，進(jin)行(xing)預熱(re)(re)和過(guo)熱(re)(re)加(jia)熱(re)(re)。Disor項(xiang)目[27]使用(yong)(yong)(yong)熔(rong)(rong)點為(wei)306℃的(de)(de)硝酸鈉(na)熔(rong)(rong)鹽(yan)(yan)(yan)作為(wei)介質(zhi)，直接與水蒸(zheng)氣進(jin)行(xing)換熱(re)(re)。此類特殊情況涉及高(gao)(gao)參數熔(rong)(rong)鹽(yan)(yan)(yan)，對熔(rong)(rong)鹽(yan)(yan)(yan)熱(re)(re)穩(wen)定性的(de)(de)要求較高(gao)(gao)。

3.1.5蒸汽加熱熔鹽的不同(tong)情況

在(zai)(zai)主(zhu)蒸(zheng)汽(qi)(qi)(qi)蓄(xu)熱(re)(re)(re)和(he)再(zai)熱(re)(re)(re)蒸(zheng)汽(qi)(qi)(qi)蓄(xu)熱(re)(re)(re)領域，熔(rong)鹽的選型(xing)存在(zai)(zai)區別。再(zai)熱(re)(re)(re)蒸(zheng)汽(qi)(qi)(qi)壓力參數較低，一般約(yue)(yue)為4 MPa，對應飽(bao)和(he)蒸(zheng)汽(qi)(qi)(qi)溫度約(yue)(yue)251℃。高溫主(zhu)蒸(zheng)汽(qi)(qi)(qi)和(he)再(zai)熱(re)(re)(re)蒸(zheng)汽(qi)(qi)(qi)分別在(zai)(zai)不同熔(rong)點的熔(rong)鹽中蓄(xu)熱(re)(re)(re)的情況如圖3所示(shi)。

由圖3a)可(ke)見(jian)，由于點(dian)(dian)a處夾點(dian)(dian)溫(wen)(wen)度(du)的(de)(de)存在(zai)(zai)，熔(rong)(rong)(rong)鹽(yan)(yan)(yan)被加(jia)熱(re)(re)(re)的(de)(de)溫(wen)(wen)度(du)受(shou)到熔(rong)(rong)(rong)鹽(yan)(yan)(yan)最低使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)和夾點(dian)(dian)溫(wen)(wen)度(du)的(de)(de)限制，其使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)范圍有限。常(chang)見(jian)的(de)(de)低熔(rong)(rong)(rong)點(dian)(dian)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)范圍為140~450℃，受(shou)到夾點(dian)(dian)溫(wen)(wen)度(du)影(ying)響，其最高(gao)溫(wen)(wen)度(du)僅(jin)能被加(jia)熱(re)(re)(re)至400℃左(zuo)右。若降低熔(rong)(rong)(rong)點(dian)(dian)，選擇熔(rong)(rong)(rong)點(dian)(dian)在(zai)(zai)100℃左(zuo)右的(de)(de)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)，其使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)上限就(jiu)可(ke)以(yi)提升至450℃，但此(ci)類熔(rong)(rong)(rong)鹽(yan)(yan)(yan)的(de)(de)應用(yong)(yong)(yong)研究尚不充分(fen)，工程實際中使(shi)用(yong)(yong)(yong)較少。若采用(yong)(yong)(yong)常(chang)規Solar鹽(yan)(yan)(yan)，其使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)為260~565℃，此(ci)時熔(rong)(rong)(rong)鹽(yan)(yan)(yan)最低工作溫(wen)(wen)度(du)已經接近(jin)飽和蒸汽(qi)(qi)線，被再(zai)熱(re)(re)(re)蒸汽(qi)(qi)加(jia)熱(re)(re)(re)的(de)(de)空間(jian)較小(xiao)，并不適用(yong)(yong)(yong)于該場景(jing)。綜上所(suo)述，在(zai)(zai)再(zai)熱(re)(re)(re)蒸汽(qi)(qi)蓄(xu)熱(re)(re)(re)的(de)(de)情景(jing)下，宜采用(yong)(yong)(yong)熔(rong)(rong)(rong)點(dian)(dian)較低的(de)(de)熔(rong)(rong)(rong)鹽(yan)(yan)(yan)，其最高(gao)使(shi)用(yong)(yong)(yong)溫(wen)(wen)度(du)無(wu)需設置過高(gao)。

與之(zhi)相反，主蒸(zheng)汽(qi)的(de)(de)參(can)數(shu)(shu)較高，以14 MPa主蒸(zheng)汽(qi)為(wei)例(li)，對(dui)(dui)應(ying)飽和蒸(zheng)汽(qi)溫(wen)(wen)(wen)(wen)度約335℃，如圖3b)點(dian)b，其夾點(dian)位置相對(dui)(dui)更高，對(dui)(dui)熔(rong)(rong)鹽(yan)加熱(re)的(de)(de)限制相對(dui)(dui)較小。圖3b)描述了同(tong)一(yi)參(can)數(shu)(shu)的(de)(de)主蒸(zheng)汽(qi)加熱(re)不(bu)同(tong)參(can)數(shu)(shu)熔(rong)(rong)鹽(yan)的(de)(de)情況，此時常(chang)見的(de)(de)低(di)熔(rong)(rong)點(dian)熔(rong)(rong)鹽(yan)工作溫(wen)(wen)(wen)(wen)度范圍為(wei)140~450℃，最(zui)高溫(wen)(wen)(wen)(wen)度可(ke)進一(yi)步拓展，而Solar鹽(yan)工作溫(wen)(wen)(wen)(wen)度約260~565℃，在此蒸(zheng)汽(qi)參(can)數(shu)(shu)下,只能被加熱(re)到420℃左右，若降低(di)熔(rong)(rong)點(dian)，則熔(rong)(rong)鹽(yan)甚至可(ke)被加熱(re)到530℃以上(shang)。由此可(ke)見，針對(dui)(dui)主蒸(zheng)汽(qi)蓄(xu)熱(re)供熱(re)場景，常(chang)規熔(rong)(rong)鹽(yan)即可(ke)適(shi)用，但(dan)是(shi)對(dui)(dui)于主蒸(zheng)汽(qi)蓄(xu)熱(re)后還(huan)要再產生蒸(zheng)汽(qi)的(de)(de)熔(rong)(rong)鹽(yan)蓄(xu)熱(re)場景，適(shi)用于熔(rong)(rong)點(dian)較低(di)但(dan)是(shi)最(zui)高溫(wen)(wen)(wen)(wen)度較高的(de)(de)寬溫(wen)(wen)(wen)(wen)域熔(rong)(rong)鹽(yan)。

3.2發電(dian)(dian)機出口(kou)電(dian)(dian)加熱熔鹽(yan)

發(fa)電(dian)(dian)(dian)(dian)機(ji)出口電(dian)(dian)(dian)(dian)加(jia)熱(re)熔(rong)鹽(yan)(yan)技術路(lu)線是利用電(dian)(dian)(dian)(dian)廠(chang)發(fa)電(dian)(dian)(dian)(dian)機(ji)出口的高(gao)壓電(dian)(dian)(dian)(dian)加(jia)熱(re)熔(rong)鹽(yan)(yan)，將儲(chu)存的熱(re)能(neng)(neng)輸出為調(diao)峰(feng)(feng)電(dian)(dian)(dian)(dian)能(neng)(neng)，即(ji)“電(dian)(dian)(dian)(dian)-熱(re)-電(dian)(dian)(dian)(dian)”轉化(hua)。所存儲(chu)的熱(re)能(neng)(neng)也可(ke)用于實現(xian)供熱(re)，即(ji)“電(dian)(dian)(dian)(dian)-熱(re)-熱(re)”轉化(hua)。電(dian)(dian)(dian)(dian)加(jia)熱(re)熔(rong)鹽(yan)(yan)儲(chu)能(neng)(neng)啟停方便，能(neng)(neng)提高(gao)現(xian)有儲(chu)熱(re)和(he)發(fa)電(dian)(dian)(dian)(dian)設備的利用率，降低(di)棄風(feng)棄光率，提升(sheng)電(dian)(dian)(dian)(dian)站效益。與(yu)光熱(re)發(fa)電(dian)(dian)(dian)(dian)和(he)電(dian)(dian)(dian)(dian)化(hua)學儲(chu)能(neng)(neng)相(xiang)比，電(dian)(dian)(dian)(dian)加(jia)熱(re)熔(rong)鹽(yan)(yan)通過(guo)在電(dian)(dian)(dian)(dian)廠(chang)發(fa)電(dian)(dian)(dian)(dian)機(ji)出口增(zeng)加(jia)電(dian)(dian)(dian)(dian)加(jia)熱(re)熔(rong)鹽(yan)(yan)裝置就(jiu)能(neng)(neng)實現(xian)，成本下降空間大；與(yu)鋰電(dian)(dian)(dian)(dian)池等(deng)儲(chu)電(dian)(dian)(dian)(dian)池相(xiang)比，其優勢為兼具火電(dian)(dian)(dian)(dian)靈(ling)活性(xing)改(gai)造的功能(neng)(neng)，滿足(zu)靈(ling)活調(diao)峰(feng)(feng)調(diao)頻等(deng)工(gong)況需要(yao)。

在電(dian)(dian)(dian)加(jia)(jia)熱(re)熔鹽的(de)使用(yong)(yong)情(qing)景下，電(dian)(dian)(dian)能直接來(lai)源于發電(dian)(dian)(dian)機出(chu)口，功率規模大，使用(yong)(yong)傳統低壓(ya)(ya)(ya)電(dian)(dian)(dian)阻式(shi)熔鹽加(jia)(jia)熱(re)器不能滿足(zu)需求。因(yin)此，需要(yao)采用(yong)(yong)高(gao)電(dian)(dian)(dian)壓(ya)(ya)(ya)加(jia)(jia)熱(re)系統如高(gao)電(dian)(dian)(dian)壓(ya)(ya)(ya)電(dian)(dian)(dian)阻式(shi)、感應式(shi)、電(dian)(dian)(dian)極式(shi)加(jia)(jia)熱(re)器。高(gao)電(dian)(dian)(dian)壓(ya)(ya)(ya)熔鹽加(jia)(jia)熱(re)器電(dian)(dian)(dian)壓(ya)(ya)(ya)等(deng)級可達6～10 kV，可避免低壓(ya)(ya)(ya)電(dian)(dian)(dian)阻式(shi)加(jia)(jia)熱(re)方案中輸(shu)電(dian)(dian)(dian)線(xian)路損耗高(gao)的(de)問題，成本較低。

“電(dian)-熱(re)(re)(re)(re)-電(dian)”熔(rong)鹽(yan)電(dian)蓄熱(re)(re)(re)(re)是一種電(dian)熱(re)(re)(re)(re)儲(chu)能，即“卡諾(nuo)電(dian)池”技術。可采(cai)用雙(shuang)罐熔(rong)鹽(yan)系統，通過(guo)冷熱(re)(re)(re)(re)罐循環放熱(re)(re)(re)(re)發電(dian)。“電(dian)-熱(re)(re)(re)(re)-熱(re)(re)(re)(re)”轉(zhuan)化的情況(kuang)下，熔(rong)鹽(yan)電(dian)蓄熱(re)(re)(re)(re)與固(gu)體蓄熱(re)(re)(re)(re)具有相似性，并(bing)且可以結合。張家口市崇(chong)禮區城(cheng)建(jian)小區使用固(gu)體蓄熱(re)(re)(re)(re)電(dian)鍋(guo)爐，綠(lv)電(dian)進(jin)入(ru)(ru)110 kV電(dian)鍋(guo)爐加熱(re)(re)(re)(re)鎂磚至500～550℃，所儲(chu)熱(re)(re)(re)(re)能再通過(guo)換熱(re)(re)(re)(re)器傳導至熱(re)(re)(re)(re)水，熱(re)(re)(re)(re)水進(jin)入(ru)(ru)集中供熱(re)(re)(re)(re)系統。

3.3煙氣蓄熱

大型火電機組中(zhong)的(de)(de)(de)高(gao)溫(wen)(wen)(wen)煙(yan)(yan)(yan)氣(qi)可達(da)700～800℃，若(ruo)能(neng)(neng)在(zai)(zai)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)中(zhong)蓄(xu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)形成穩定熱(re)(re)(re)(re)(re)(re)(re)(re)(re)源，就可以(yi)實現(xian)較(jiao)高(gao)參數的(de)(de)(de)可持續(xu)供暖或供生活熱(re)(re)(re)(re)(re)(re)(re)(re)(re)水(shui)，同時也使鍋爐適(shi)應熱(re)(re)(re)(re)(re)(re)(re)(re)(re)負荷變化較(jiao)大的(de)(de)(de)供熱(re)(re)(re)(re)(re)(re)(re)(re)(re)需要，提(ti)(ti)高(gao)機組調峰(feng)能(neng)(neng)力。熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)煙(yan)(yan)(yan)氣(qi)蓄(xu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)涉及高(gao)參數熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)以(yi)及特(te)殊的(de)(de)(de)煙(yan)(yan)(yan)氣(qi)-熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)。目前，關于(yu)高(gao)溫(wen)(wen)(wen)煙(yan)(yan)(yan)氣(qi)與熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)的(de)(de)(de)儲熱(re)(re)(re)(re)(re)(re)(re)(re)(re)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)設(she)(she)備有許多設(she)(she)計(ji)，如引導煙(yan)(yan)(yan)氣(qi)穿過(guo)加熱(re)(re)(re)(re)(re)(re)(re)(re)(re)棒，實現(xian)高(gao)溫(wen)(wen)(wen)煙(yan)(yan)(yan)氣(qi)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)儲熱(re)(re)(re)(re)(re)(re)(re)(re)(re)的(de)(de)(de)特(te)殊換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)通道[28]，以(yi)及利(li)用(yong)(yong)高(gao)溫(wen)(wen)(wen)煙(yan)(yan)(yan)氣(qi)加熱(re)(re)(re)(re)(re)(re)(re)(re)(re)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)的(de)(de)(de)自冷卻屏(ping)式加熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)[29]等，其優勢在(zai)(zai)于(yu)傳熱(re)(re)(re)(re)(re)(re)(re)(re)(re)溫(wen)(wen)(wen)差大，熱(re)(re)(re)(re)(re)(re)(re)(re)(re)量(liang)品位(wei)高(gao)。煙(yan)(yan)(yan)氣(qi)-熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)還(huan)可收集(ji)煉鋼過(guo)程中(zhong)產(chan)生的(de)(de)(de)高(gao)溫(wen)(wen)(wen)余(yu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)，由(you)多根并聯的(de)(de)(de)金屬管組成并設(she)(she)置(zhi)在(zai)(zai)煙(yan)(yan)(yan)腔內[30]。通過(guo)煙(yan)(yan)(yan)氣(qi)-熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)收集(ji)煙(yan)(yan)(yan)氣(qi)廢熱(re)(re)(re)(re)(re)(re)(re)(re)(re)，可通過(guo)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)雙罐(guan)系統實現(xian)再利(li)用(yong)(yong)。利(li)用(yong)(yong)雙罐(guan)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)中(zhong)儲熱(re)(re)(re)(re)(re)(re)(re)(re)(re)實現(xian)發(fa)電的(de)(de)(de)循環包括：低(di)溫(wen)(wen)(wen)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)從煙(yan)(yan)(yan)氣(qi)出口(kou)進入換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)管束，與煙(yan)(yan)(yan)氣(qi)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)成為高(gao)溫(wen)(wen)(wen)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)；依(yi)次經(jing)過(guo)過(guo)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)、蒸(zheng)發(fa)器(qi)、預熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)加熱(re)(re)(re)(re)(re)(re)(re)(re)(re)給(gei)水(shui)，輸出過(guo)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)蒸(zheng)汽(qi)(qi)驅(qu)動汽(qi)(qi)輪機發(fa)電，換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)后的(de)(de)(de)低(di)溫(wen)(wen)(wen)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)回到儲罐(guan)[31]。現(xian)有的(de)(de)(de)高(gao)溫(wen)(wen)(wen)煙(yan)(yan)(yan)氣(qi)熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)器(qi)適(shi)用(yong)(yong)溫(wen)(wen)(wen)度范圍較(jiao)小(xiao)，無法利(li)用(yong)(yong)低(di)濃度煙(yan)(yan)(yan)氣(qi)的(de)(de)(de)余(yu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)，在(zai)(zai)安全性和蓄(xu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)換(huan)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)能(neng)(neng)力方面(mian)依(yi)然有待(dai)提(ti)(ti)高(gao)。表4為蒸(zheng)汽(qi)(qi)、電蓄(xu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)、煙(yan)(yan)(yan)氣(qi)蓄(xu)熱(re)(re)(re)(re)(re)(re)(re)(re)(re)情景下對熔(rong)鹽(yan)(yan)(yan)(yan)(yan)(yan)儲能(neng)(neng)技(ji)術的(de)(de)(de)選擇。

4、熔鹽儲能在綠電供熱領域的應用

新能源(yuan)發電(dian)(dian)稱作綠(lv)電(dian)(dian)，綠(lv)電(dian)(dian)供熱(re)(re)(re)是新能源(yuan)消(xiao)納的(de)(de)(de)一種(zhong)新途(tu)徑，是指(zhi)使(shi)用低(di)谷電(dian)(dian)或風、光富余電(dian)(dian)量加熱(re)(re)(re)熔(rong)(rong)鹽(yan)(yan)，經過電(dian)(dian)-熔(rong)(rong)鹽(yan)(yan)-給(gei)(gei)水(shui)(shui)的(de)(de)(de)熱(re)(re)(re)傳遞(di)，用于入(ru)戶供暖。一般通過雙罐熔(rong)(rong)鹽(yan)(yan)系統來實現綠(lv)電(dian)(dian)供熱(re)(re)(re)，其原理(li)如(ru)(ru)圖4所示[31]。使(shi)用綠(lv)電(dian)(dian)棄(qi)電(dian)(dian)或谷電(dian)(dian)將(jiang)熔(rong)(rong)鹽(yan)(yan)加熱(re)(re)(re)并儲(chu)存在高(gao)(gao)溫熔(rong)(rong)鹽(yan)(yan)罐中(zhong)，白(bai)天將(jiang)高(gao)(gao)溫熔(rong)(rong)鹽(yan)(yan)從罐中(zhong)抽出，通過熔(rong)(rong)鹽(yan)(yan)換(huan)熱(re)(re)(re)器加熱(re)(re)(re)給(gei)(gei)水(shui)(shui)，滿足多種(zhong)需求。如(ru)(ru)供給(gei)(gei)90℃熱(re)(re)(re)水(shui)(shui)實現常規(gui)居民供熱(re)(re)(re)，供給(gei)(gei)180～360℃的(de)(de)(de)中(zhong)低(di)溫工業(ye)蒸汽(qi)(qi)，以及500℃以上的(de)(de)(de)高(gao)(gao)溫蒸汽(qi)(qi)。換(huan)熱(re)(re)(re)后降溫的(de)(de)(de)熔(rong)(rong)鹽(yan)(yan)再流入(ru)低(di)溫熔(rong)(rong)鹽(yan)(yan)罐，完成循環。

綠電(dian)(dian)(dian)供(gong)(gong)(gong)(gong)(gong)熱(re)(re)(re)是一(yi)種高(gao)效(xiao)的(de)(de)清(qing)潔(jie)供(gong)(gong)(gong)(gong)(gong)暖(nuan)方式(shi)，在各地(di)(di)已開展試(shi)點工程(cheng)。河北(bei)辛集熔(rong)鹽(yan)(yan)蓄(xu)熱(re)(re)(re)低谷(gu)電(dian)(dian)(dian)綠色供(gong)(gong)(gong)(gong)(gong)暖(nuan)示范工程(cheng)[32]以低熔(rong)點鹽(yan)(yan)作為傳熱(re)(re)(re)、蓄(xu)熱(re)(re)(re)工質，利用(yong)電(dian)(dian)(dian)網10 h的(de)(de)低谷(gu)電(dian)(dian)(dian)力加熱(re)(re)(re)熔(rong)鹽(yan)(yan)用(yong)于供(gong)(gong)(gong)(gong)(gong)給(gei)生活熱(re)(re)(re)水(shui)，儲(chu)熱(re)(re)(re)時長16 h。北(bei)京市燃氣(qi)熱(re)(re)(re)力供(gong)(gong)(gong)(gong)(gong)熱(re)(re)(re)中心(xin)[33]將夜間低谷(gu)綠電(dian)(dian)(dian)轉(zhuan)化為熱(re)(re)(re)能(neng)儲(chu)存(cun)在180～390℃的(de)(de)熔(rong)鹽(yan)(yan)中，白天使用(yong)熔(rong)鹽(yan)(yan)儲(chu)熱(re)(re)(re)為北(bei)京西站(zhan)地(di)(di)區供(gong)(gong)(gong)(gong)(gong)暖(nuan)，同時對外供(gong)(gong)(gong)(gong)(gong)應(ying)穩定的(de)(de)中低溫工業(ye)蒸(zheng)汽。與燃氣(qi)供(gong)(gong)(gong)(gong)(gong)暖(nuan)相(xiang)比，綠電(dian)(dian)(dian)供(gong)(gong)(gong)(gong)(gong)熱(re)(re)(re)的(de)(de)運行費(fei)用(yong)更低；與熱(re)(re)(re)泵供(gong)(gong)(gong)(gong)(gong)暖(nuan)技術相(xiang)比，其初(chu)投資較(jiao)低；與水(shui)蓄(xu)熱(re)(re)(re)式(shi)電(dian)(dian)(dian)采暖(nuan)相(xiang)比，其優勢在于占地(di)(di)面積小，蓄(xu)能(neng)密(mi)度高(gao)。部分綠電(dian)(dian)(dian)供(gong)(gong)(gong)(gong)(gong)熱(re)(re)(re)機(ji)組能(neng)夠同時供(gong)(gong)(gong)(gong)(gong)應(ying)100℃以下的(de)(de)民(min)用(yong)熱(re)(re)(re)水(shui)和各類工業(ye)蒸(zheng)汽，熱(re)(re)(re)效(xiao)率(lv)較(jiao)高(gao)，為火(huo)電(dian)(dian)(dian)機(ji)組改造提供(gong)(gong)(gong)(gong)(gong)了(le)新方向。

綠(lv)電(dian)(dian)供(gong)(gong)(gong)熱(re)(re)涉及的(de)(de)關(guan)鍵技術(shu)為安全穩定的(de)(de)雙罐系(xi)統、高(gao)效率的(de)(de)換熱(re)(re)器(qi)和高(gao)電(dian)(dian)壓(ya)熔(rong)(rong)(rong)(rong)鹽(yan)(yan)電(dian)(dian)加(jia)熱(re)(re)器(qi)。普通生活(huo)熱(re)(re)水(shui)供(gong)(gong)(gong)應系(xi)統中(zhong)常使用(yong)浮動(dong)盤管(guan)型(xing)彈性管(guan)束換熱(re)(re)器(qi)，而(er)在熔(rong)(rong)(rong)(rong)鹽(yan)(yan)-水(shui)換熱(re)(re)的(de)(de)情景下(xia)，需(xu)要在管(guan)殼式熔(rong)(rong)(rong)(rong)鹽(yan)(yan)換熱(re)(re)器(qi)的(de)(de)基礎上(shang)進行改造優(you)化。由于(yu)(yu)直接(jie)(jie)接(jie)(jie)入(ru)電(dian)(dian)網的(de)(de)熔(rong)(rong)(rong)(rong)鹽(yan)(yan)加(jia)熱(re)(re)器(qi)可(ke)以節省(sheng)變電(dian)(dian)成本，綠(lv)電(dian)(dian)供(gong)(gong)(gong)熱(re)(re)也(ye)需(xu)要成熟(shu)可(ke)靠的(de)(de)高(gao)電(dian)(dian)壓(ya)熔(rong)(rong)(rong)(rong)鹽(yan)(yan)加(jia)熱(re)(re)器(qi)，如各類高(gao)壓(ya)電(dian)(dian)阻式、電(dian)(dian)極式、電(dian)(dian)磁感應式加(jia)熱(re)(re)器(qi)。對于(yu)(yu)部分只提供(gong)(gong)(gong)民用(yong)熱(re)(re)水(shui)或中(zhong)低溫工業蒸汽的(de)(de)機組，也(ye)可(ke)直接(jie)(jie)采用(yong)380 V電(dian)(dian)極式或電(dian)(dian)阻式熔(rong)(rong)(rong)(rong)鹽(yan)(yan)加(jia)熱(re)(re)爐。總(zong)結(jie)綠(lv)電(dian)(dian)供(gong)(gong)(gong)熱(re)(re)不同技術(shu)路線適用(yong)的(de)(de)關(guan)鍵技術(shu)見表5。

在綠電(dian)供熱(re)(re)場(chang)景中，由熔(rong)鹽加熱(re)(re)蒸汽或(huo)過冷水(shui)，應根據不同的情況(kuang)選擇低參(can)數或(huo)高參(can)數熔(rong)鹽。綠電(dian)供熱(re)(re)中熔(rong)鹽蒸汽換熱(re)(re)情況(kuang)如圖5所示(shi)。

由圖5a)可見，蒸(zheng)汽(qi)的(de)升溫(wen)受到夾(jia)點a的(de)限制，若(ruo)要(yao)(yao)輸出(chu)超過500℃的(de)高(gao)溫(wen)工業蒸(zheng)汽(qi)，就需要(yao)(yao)提(ti)高(gao)熔鹽(yan)的(de)蓄熱溫(wen)度至約600℃，選用高(gao)參(can)數熔鹽(yan)與蒸(zheng)汽(qi)進行換熱。在供應(ying)中低(di)(di)溫(wen)工業蒸(zheng)汽(qi)時，使(shi)用熔點較(jiao)低(di)(di)的(de)硝(xiao)酸鹽(yan)熔鹽(yan)即(ji)能滿足需求（圖5b)）。熔鹽(yan)加熱蒸(zheng)汽(qi)的(de)過程受夾(jia)點b溫(wen)度限制，最終(zhong)在低(di)(di)參(can)數熔鹽(yan)工作區(qu)間(jian)150~450℃，可供應(ying)1.2 MPa、370℃的(de)蒸(zheng)汽(qi)。

5、結論

1）目前(qian)，熔(rong)(rong)鹽儲能相關技術(shu)多(duo)樣，但各項關鍵技術(shu)都存在欠缺,限(xian)制(zhi)了熔(rong)(rong)鹽儲能在新型電力(li)系統中(zhong)的(de)(de)(de)應用發展(zhan)。目前(qian)，在多(duo)元混合(he)熔(rong)(rong)鹽領域，低熔(rong)(rong)點鹽主要是(shi)鋰、鈣、鉀等(deng)元素的(de)(de)(de)硝酸鹽和亞硝酸鹽體系，如Hitec鹽。耐(nai)高(gao)溫鹽中(zhong)氯化鹽的(de)(de)(de)腐蝕性(xing)以及碳(tan)酸鹽的(de)(de)(de)易分解性(xing)缺陷，還需(xu)要展(zhan)開(kai)針對研究，為市場提供(gong)更多(duo)商業化熔(rong)(rong)鹽材(cai)料。

另外，在熔(rong)鹽(yan)(yan)儲(chu)(chu)罐的預熱(re)、變工況方(fang)面(mian)研究(jiu)不(bu)足(zu)，大型(xing)高(gao)(gao)溫(wen)熔(rong)鹽(yan)(yan)儲(chu)(chu)罐缺乏(fa)完善的制造(zao)標準和規(gui)范。市場缺乏(fa)成(cheng)熟的高(gao)(gao)電(dian)壓(ya)等級熔(rong)鹽(yan)(yan)電(dian)加(jia)熱(re)器(qi)，部分電(dian)磁(ci)感應加(jia)熱(re)器(qi)雖可接入(ru)高(gao)(gao)電(dian)壓(ya)，但(dan)成(cheng)本較高(gao)(gao)，并不(bu)具備普遍(bian)實施性。目前(qian)，廣泛(fan)采用的傳統管殼(ke)式換(huan)熱(re)器(qi)，存在未兼顧以熔(rong)鹽(yan)(yan)為(wei)工質的情(qing)況，缺少針對優化熔(rong)鹽(yan)(yan)換(huan)熱(re)器(qi)的構型(xing)展開的實驗研究(jiu)。

2）熔鹽儲能(neng)系統的技術突破能(neng)提(ti)高效(xiao)率(lv)、降低成本(ben)，也(ye)是增(zeng)強光熱(re)電(dian)(dian)(dian)站競爭(zheng)力的關鍵所在。目(mu)前在光熱(re)領域，我國已具備了支撐光熱(re)發電(dian)(dian)(dian)大規模發展的基(ji)礎。太(tai)陽能(neng)光熱(re)發電(dian)(dian)(dian)的成本(ben)控制主要通過提(ti)高系統效(xiao)率(lv)和降低設備成本(ben)2方面來實現。

在提高(gao)系(xi)(xi)統效率(lv)方面主(zhu)要(yao)有(you)2種途徑：①高(gao)參(can)數(shu)光(guang)熱(re)發電(dian)，使用溫(wen)度區間和(he)儲(chu)熱(re)容量更(geng)大，循(xun)環(huan)效率(lv)更(geng)高(gao)；②光(guang)熱(re)耦合新(xin)型動(dong)力循(xun)環(huan)，如熔(rong)鹽(yan)儲(chu)能耦合S-CO2光(guang)熱(re)發電(dian)系(xi)(xi)統，需(xu)(xu)要(yao)采(cai)用耐高(gao)溫(wen)高(gao)壓的(de)印(yin)刷(shua)電(dian)路板換熱(re)器，儲(chu)熱(re)系(xi)(xi)統溫(wen)度需(xu)(xu)超過700℃，但目前還(huan)沒有(you)成(cheng)熟(shu)的(de)商(shang)用熔(rong)鹽(yan)可(ke)以(yi)滿足需(xu)(xu)求，存在技術瓶(ping)頸。

降低成本應從熔(rong)(rong)鹽儲(chu)能關鍵技術(shu)入(ru)手，如關于(yu)下(xia)一代光熱電站熔(rong)(rong)鹽的選型(xing)，期望同(tong)時滿足低熔(rong)(rong)點、耐高溫、低成本的要求。但關于(yu)不同(tong)熔(rong)(rong)鹽、儲(chu)罐(guan)、加熱器等(deng)的選型(xing)還(huan)需要進(jin)一步細化行業標準(zhun)，形成規范評價體(ti)系，促進(jin)技術(shu)配套實現。

3）火電機組(zu)與熔鹽儲能結合是(shi)增(zeng)加機組(zu)靈活性(xing)，提高(gao)全過程循環效率的有效方(fang)式。但目前針對火電機組(zu)與熔鹽儲能耦合的運(yun)行工(gong)況研究較(jiao)少，雙罐系統在(zai)其中的安(an)全性(xing)保證(zheng)仍需(xu)進(jin)一步實踐研究。

現(xian)有熔(rong)鹽-火電耦(ou)合發(fa)電系統的(de)(de)研究(jiu)范圍多針(zhen)對(dui)主蒸汽(qi)溫度620℃以(yi)下的(de)(de)機組，關(guan)于超超臨界機組主蒸汽(qi)溫度620℃以(yi)上的(de)(de)熔(rong)鹽蒸汽(qi)蓄熱還(huan)缺乏成熟(shu)落地的(de)(de)方案。目前，抽(chou)取再(zai)熱或過熱蒸汽(qi)加熱熔(rong)鹽的(de)(de)方案可行性(xing)已被證實(shi)，但具體抽(chou)汽(qi)量的(de)(de)標準尚不(bu)明(ming)確，對(dui)火電系統整體的(de)(de)負(fu)面影響也需要進一步(bu)對(dui)比研究(jiu)。

注：本文轉自《熱力發電》期刊，聯合作者為西安熱工研究院有限公司左芳菲，韓偉，姚明宇。轉載此文是出于傳遞更多信息之目的，若有來源標注錯誤或侵犯了您的合法權益，請作者與本網聯系。