劉麗艷,石?凱,吳?桐,譚?蔚,汪?洋
多噴嘴對(duì)置式煤氣化爐激冷室顆粒運(yùn)動(dòng)及碰撞特性研究
劉麗艷1, 2,石?凱1,吳?桐1,譚?蔚1,汪?洋1
(1. 天津大學(xué)化工學(xué)院,天津 300350;2. 天津市化工安全與裝備技術(shù)重點(diǎn)實(shí)驗(yàn)室,天津 300350)
多噴嘴對(duì)置式水煤漿氣化技術(shù)是我國(guó)自主研發(fā)的一種潔凈煤技術(shù),具有轉(zhuǎn)化率高、有效氣含量高等優(yōu)點(diǎn).氣化爐是煤氣化工藝的核心設(shè)備之一,其主體結(jié)構(gòu)包括燃燒室與激冷室兩部分.燃燒室反應(yīng)生成的粗合成氣夾帶固體灰渣顆粒進(jìn)入激冷室液池,在氣液兩相湍流作用下與爐體發(fā)生碰撞,造成沖蝕磨蝕等破壞,對(duì)氣化爐安全和長(zhǎng)周期穩(wěn)定運(yùn)行造成影響.本文以多噴嘴對(duì)置式氣化爐為研究對(duì)象,建立了激冷室三維物理模型;利用VOF多相流模型和DPM離散相模型研究了氣液固三相流場(chǎng),得到連續(xù)流場(chǎng)和不同粒徑顆粒的分布狀態(tài);通過(guò)Fluent UDF對(duì)灰渣顆粒與爐體碰撞位置和碰撞參數(shù)進(jìn)行了統(tǒng)計(jì)分析,得到激冷室內(nèi)碰撞多發(fā)區(qū)域及破壞機(jī)理.研究結(jié)果表明:合成氣進(jìn)入激冷室液池中形成負(fù)浮力射流,動(dòng)量逐漸衰減,最終改變運(yùn)動(dòng)方向而向上反折流動(dòng);不同粒徑的顆粒在激冷室流場(chǎng)中的分布不同,粒徑較小的顆粒氣相跟隨性更為明顯,分布范圍更廣;顆粒粒徑影響其與激冷室壁面主要碰撞區(qū)域,粒徑為0.05mm和0.1mm的小尺寸灰渣顆粒碰撞主要發(fā)生在下降管下端;0.5mm的大尺寸灰渣顆粒碰撞主要發(fā)生在激冷室爐體下部,在設(shè)計(jì)制造過(guò)程中要重點(diǎn)關(guān)注;分析碰撞角度發(fā)現(xiàn)各壁面碰撞破壞機(jī)理不同:下降管下端壁面主要是撞擊磨損;激冷室爐體則是沖刷磨損和撞擊磨損的耦合作用.
多噴嘴對(duì)置式水煤漿氣化爐;激冷室;灰渣顆粒;磨損;數(shù)值模擬
多噴嘴對(duì)置式水煤漿氣化技術(shù)是我國(guó)自主研發(fā)的一種潔凈煤技術(shù).該技術(shù)利用4個(gè)對(duì)稱分布燒嘴射流產(chǎn)生的撞擊作用減小反應(yīng)盲區(qū)、強(qiáng)化熱質(zhì)傳遞過(guò)程從而提高固體燃料轉(zhuǎn)化率和合成氣中有效氣體成分含量[1-2],同時(shí)對(duì)激冷室內(nèi)流場(chǎng)、合成氣脫灰、激冷水熱量回收等過(guò)程進(jìn)行了優(yōu)化[3].
多噴嘴對(duì)置式水煤漿氣化爐包括燃燒室與激冷室兩部分.燃燒室反應(yīng)生成的粗合成氣通過(guò)下降管進(jìn)入激冷室,完成初步的洗滌冷卻后進(jìn)入后續(xù)工序.高溫合成氣與激冷水在下降管內(nèi)接觸并發(fā)生強(qiáng)烈的熱質(zhì)交換,合成氣中熔融狀態(tài)的灰渣遇冷發(fā)生聚并與凝結(jié)[2].下降管出口浸入激冷室液池中,進(jìn)入液池后大部分灰渣顆粒被液池捕捉,部分顆粒隨合成氣進(jìn)入后續(xù)工序.由于高溫高壓、多相相變及強(qiáng)湍流等復(fù)雜工作環(huán)境導(dǎo)致?tīng)t體材料常產(chǎn)生沖蝕、磨蝕等損傷,對(duì)煤氣化爐的安全穩(wěn)定運(yùn)行帶來(lái)潛在威脅.研究煤氣化爐激冷室多相流場(chǎng)分布和固相顆粒運(yùn)動(dòng)特性,分析氣化爐沖蝕和磨蝕危險(xiǎn)區(qū)域,可為煤氣化爐的設(shè)計(jì)制造和運(yùn)行參數(shù)優(yōu)化提供參考.國(guó)內(nèi)外學(xué)者對(duì)此進(jìn)行了大量研究,Kurowski等[4]對(duì)氣化爐成渣過(guò)程進(jìn)行了模擬,對(duì)灰渣的顆粒、速度以及溫度分布進(jìn)行了研究;吳晅等[5-7]分別建立了二維和三維軸對(duì)稱激冷室模型,分析灰渣顆粒在流場(chǎng)中的受力,研究了液池對(duì)不同粒徑灰渣顆粒的捕捉效率;Li等[8]利用DPM模型研究了氣化爐燃燒室內(nèi)煤粉顆粒運(yùn)動(dòng)軌跡和停留時(shí)間;姜峰等[9]利用CCD圖像采集和數(shù)據(jù)處理系統(tǒng),研究了不同操作條件對(duì)加熱管束中固體顆粒分布的影響.田華等[10]建立了考慮顆粒黏附和反彈行為的碳煙顆粒沉積數(shù)值模型,研究了不同流速與粒徑下管排換熱器內(nèi)的顆粒沉積分布.
上述研究主要關(guān)注顆粒的分布特性,對(duì)顆粒與壁面的碰撞未做深入研究.本文建立了多噴嘴對(duì)置式水煤漿氣化爐激冷室的物理模型,利用VOF多相流模型和DPM離散相模型構(gòu)建了三相流場(chǎng)數(shù)值計(jì)算模型.通過(guò)分析激冷室內(nèi)連續(xù)相分布,得到顆粒所處的流場(chǎng)環(huán)境;對(duì)不同尺寸灰渣顆粒在氣化爐激冷室流場(chǎng)中的運(yùn)動(dòng)軌跡、顆粒與爐體的碰撞位置進(jìn)行了研究,得到激冷室磨蝕危險(xiǎn)區(qū)域,為氣化爐設(shè)計(jì)和結(jié)構(gòu)優(yōu)化提供參考.同時(shí)對(duì)危險(xiǎn)位置的碰撞參數(shù)進(jìn)行分析,為爐體碰撞損傷機(jī)理研究提供基礎(chǔ)數(shù)據(jù).
本文以兗礦魯南化工有限公司的6.5MPa級(jí)多噴嘴對(duì)置式水煤漿氣化爐為研究對(duì)象,不考慮靜態(tài)破渣器、破泡床和下降管支管等激冷室內(nèi)件對(duì)流場(chǎng)的影響,建立了三維物理模型,如圖1所示.模型各尺寸見(jiàn)表1.
圖1?激冷室物理模型
表1?激冷室模型尺寸
Tab.1 Main dimensions of the water-scrubbing cooling chamber mm
激冷室是三維圓柱狀套筒結(jié)構(gòu),整體尺寸較大,直接劃分四面體網(wǎng)格數(shù)量多且網(wǎng)格質(zhì)量較差.故本文將模型分為6個(gè)部分,分塊劃分網(wǎng)格,分塊及劃分結(jié)果如圖2所示.
對(duì)模型的網(wǎng)格無(wú)關(guān)性進(jìn)行了檢驗(yàn),比較粒徑為0.05mm、計(jì)算時(shí)間為15s時(shí)顆粒在不同網(wǎng)格尺寸下的逃逸率,結(jié)果如圖3所示.網(wǎng)格總體尺寸分別為20mm、30mm和40mm,由圖可見(jiàn)知:20mm與30mm網(wǎng)格下逃逸率相差較小,但40mm網(wǎng)格的逃逸率相較偏差較大.故本文綜合考慮計(jì)算精度和計(jì)算量后,選擇尺寸為30mm的網(wǎng)格進(jìn)行計(jì)算,網(wǎng)格數(shù)量為1404萬(wàn).
圖2?網(wǎng)格劃分結(jié)果
圖3?不同尺寸網(wǎng)格下0.05mm顆粒逃逸率
合成氣和熔融態(tài)的灰渣在下降管內(nèi)發(fā)生熱質(zhì)傳遞、相變等過(guò)程,本文主要考慮灰渣顆粒在激冷室內(nèi)的運(yùn)動(dòng),故以下降管出口作為激冷室流場(chǎng)模擬計(jì)算的入口以簡(jiǎn)化計(jì)算.假設(shè)下降管入口氣速恒定,結(jié)合文獻(xiàn)[11-12]確定操作條件進(jìn)而確定模擬計(jì)算的邊界條件,如表2所示.
表2?多噴嘴對(duì)置式水煤漿氣化爐操作條件
Tab.2 Operating conditions of the opposed multi-burner gasifier
激冷室內(nèi)連續(xù)相為合成氣和激冷水的兩相流動(dòng),選擇VOF多相流模型可追蹤氣液兩相自由界面,準(zhǔn)確模擬氣液兩相耦合流動(dòng)行為[13-15].離散顆粒運(yùn)動(dòng)利用DPM離散相模型[16-17],考慮離散相與連續(xù)相間的耦合作用.入口為速度入口,出口為壓力出口,其他計(jì)算設(shè)置見(jiàn)表3.
表3?數(shù)值模擬計(jì)算設(shè)置
Tab.3?Numerical calculation settings
在本文的離散相計(jì)算中,考慮的離散項(xiàng)顆粒在流場(chǎng)中的受力包括重力、浮力、虛擬質(zhì)量力、壓力梯度力和薩夫曼升力[18],簡(jiǎn)要介紹如下.
1) 虛擬質(zhì)量力A
當(dāng)顆粒在流體中加速運(yùn)動(dòng)時(shí)會(huì)引起周圍的流體一起加速,由于流體的慣性作用,顆粒會(huì)受到流體的反作用力,故推動(dòng)顆粒運(yùn)動(dòng)的力大于顆粒自身的慣性力.這部分力稱為虛擬質(zhì)量力:
式中:p為顆粒半徑,m;t為流體密度,kg/m3;c為周圍流體速度,m/s;p為顆粒運(yùn)動(dòng)速度,m/s.
2) 壓力梯度力p
顆粒在壓力不為常數(shù)的流場(chǎng)中運(yùn)動(dòng)時(shí),會(huì)由于壓力梯度的存在受到壓力梯度力,其大小與壓力梯度及粒徑有關(guān):
3) 薩夫曼升力S
當(dāng)固體顆粒在有速度梯度的流場(chǎng)中運(yùn)動(dòng)時(shí),由于顆粒上下兩側(cè)的流速不相同,會(huì)產(chǎn)生一個(gè)由低速區(qū)指向高速區(qū)的升力.其表達(dá)式如下:
顆粒在激冷室中的運(yùn)動(dòng)與連續(xù)相流場(chǎng)密切相關(guān),研究激冷室流場(chǎng)對(duì)分析顆粒停留位置和運(yùn)動(dòng)狀態(tài)有重要意義.通過(guò)瞬態(tài)數(shù)值模擬可以得到不同時(shí)刻氣液兩相分布,以粒徑為0.05mm的顆粒為例對(duì)不同時(shí)刻激冷室內(nèi)氣液兩相分布云圖進(jìn)行整理分析,如圖4所示.
圖4?不同時(shí)刻激冷室氣液分布云圖
由圖4可知,氣體由下降管進(jìn)入液池形成負(fù)浮力射流,在豎直向上的浮力以及壓力梯度力的作用下,氣體的初始動(dòng)量逐漸發(fā)生衰減,最終改變運(yùn)動(dòng)方向而向上反折流動(dòng),兩相分布云圖與文獻(xiàn)[5]中的結(jié)果一致.在上升的過(guò)程中氣體不斷卷吸周圍的液相形成液沫夾帶,兩相間進(jìn)行動(dòng)量傳遞.
研究灰渣顆粒在激冷室內(nèi)的分布對(duì)顆粒運(yùn)動(dòng)和顆粒與壁面碰撞位置分析具有重要意義.合成氣攜帶顆粒從下降管進(jìn)入激冷室液池,顆粒在重力和流場(chǎng)作用在激冷室內(nèi)運(yùn)動(dòng).根據(jù)式(4)對(duì)不同顆粒在下降管內(nèi)的斯托克斯數(shù)進(jìn)行了計(jì)算.
式中:p為顆粒密度,kg/m3;為下降管直徑,m.
粒徑為0.05mm、0.1mm和0.5mm的顆粒在下降管流場(chǎng)中對(duì)應(yīng)分別為0.0465、0.1862和4.6544,即0.05mm和0.1mm跟隨性能更好.但進(jìn)入激冷室后顆粒運(yùn)動(dòng)受到氣液兩相復(fù)雜流場(chǎng)的作用,斯托克斯數(shù)會(huì)發(fā)生變化且難以直接計(jì)算得到.故本文對(duì)各粒徑的顆粒不同時(shí)刻在激冷室的分布位置進(jìn)一步研究,分析不同顆粒在復(fù)雜流場(chǎng)下的運(yùn)動(dòng),如圖5所示.
由顆粒停留位置結(jié)合連續(xù)相流場(chǎng)分析結(jié)果可知:粒徑為0.05mm和0.1mm的顆粒由于粒徑較小,流體的曳力作用對(duì)其影響更為顯著,大量顆粒隨合成氣向上擴(kuò)散,被氣相帶出液池的顆粒隨合成氣逐漸充滿整個(gè)激冷室,部分隨氣體從出口逃逸.粒徑為0.5mm的灰渣顆粒受慣性力作用更為顯著,不易被合成氣攜帶,因此顆粒隨合成氣進(jìn)入液池后,大部分被液池捕獲,部分隨合成氣向上運(yùn)動(dòng)至一定高度后逐漸沉降.
圖5?不同時(shí)刻顆粒位置
研究爐體碰撞多發(fā)區(qū)域可在設(shè)計(jì)制造中針對(duì)性做出防護(hù)和改進(jìn)措施.在模擬計(jì)算中利用Fluent UDF實(shí)現(xiàn)對(duì)顆粒碰撞的位置、角度等參數(shù)的提取并對(duì)此進(jìn)行了相關(guān)分析.為方便討論,對(duì)激冷室爐體壁面各區(qū)域分塊命名,見(jiàn)圖6.
在計(jì)算時(shí)間內(nèi),粒徑為0.05mm、0.1mm和0.5mm的顆粒與壁面分別發(fā)生359578、358060、168552次碰撞.由于粒徑大的顆粒氣相跟隨性較差,進(jìn)入激冷室液池后大部分被捕獲逐漸沉降,故其與壁面發(fā)生碰撞概率較小,這與顆粒分布分析結(jié)果對(duì)應(yīng).對(duì)不同粒徑顆粒在不同區(qū)域發(fā)生碰撞的比例進(jìn)行比較,如表4所示.
圖6?爐體壁面命名示意
表4?不同粒徑顆粒與各壁面發(fā)生碰撞占比
Tab.4 Proportion of the collision of particles with differ-ent sizes
由表4所示,0.05mm顆粒和0.1mm顆粒碰撞主要發(fā)生在面4-2,即下降管下端壁面;0.5mm的顆粒碰撞主要發(fā)生在面3-1、面4-1、面5-1和面6-1,即激冷室內(nèi)壁面下部.由連續(xù)相氣液分布可知?dú)怏w在反折向上流動(dòng)過(guò)程中在下降管壁面附近聚集,粒徑較小的顆粒在湍動(dòng)的合成氣攜帶下易與下降管下端壁面發(fā)生碰撞;而粒徑較大的顆粒受重力效應(yīng)影響較大,易被液池捕獲,在激冷室內(nèi)整體分布較為集中并快速聚集下沉,下沉過(guò)程與激冷室內(nèi)壁發(fā)生碰撞.圖7是兗礦某多噴嘴對(duì)置式煤氣化爐停車檢修時(shí)拍攝的激冷室磨蝕破壞圖,可以發(fā)現(xiàn)下降管下端是破壞最嚴(yán)重的區(qū)域,這與本文的模擬計(jì)算結(jié)果一致.
圖7?下降管破壞情況
沖蝕磨蝕損傷根據(jù)顆粒碰撞形式不同分為沖刷磨損和撞擊磨損兩類.沖刷磨損是顆粒以較小或與壁面相對(duì)平行的沖擊角對(duì)壁面進(jìn)行撞擊的一種現(xiàn)象,而撞擊磨損是顆粒以較大或接近垂直的沖擊角對(duì)壁面進(jìn)行撞擊的現(xiàn)象[17].為進(jìn)一步研究各壁面損傷形式,對(duì)顆粒與爐體碰撞的碰撞角度進(jìn)行了統(tǒng)計(jì)分析.
由圖8可知,不同粒徑顆粒在其主要碰撞區(qū)域發(fā)生碰撞的碰撞角度明顯不同,粒徑為0.05mm和0.1mm的灰渣顆粒在其主要碰撞區(qū)面4-2處的碰撞角主要集中在30°~60°范圍內(nèi);粒徑為0.5mm的灰渣顆粒在面3-1處的碰撞角分布在10°~30°和30°~60°范圍內(nèi),在面4-1處的碰撞角主要分布在0°~30°內(nèi).碰撞角度分析結(jié)果表明激冷室內(nèi)各壁面破壞機(jī)理不同,下降管下端壁面主要是撞擊磨損;激冷室爐體則是沖刷磨損和撞擊磨損的耦合作用.
圖8?不同主要碰撞區(qū)碰撞角分布
本文針對(duì)激冷室內(nèi)存在的沖蝕、磨蝕等破壞,采用數(shù)值模擬的方法進(jìn)行了研究.建立了激冷室三維物理模型和數(shù)值模擬模型,應(yīng)用VOF多相流模型、DPM離散相模型和Fluent UDF對(duì)激冷室流場(chǎng)、顆粒運(yùn)動(dòng)及其與激冷室壁面碰撞參數(shù)分析研究得到如下結(jié)論.
(1) 合成氣進(jìn)入激冷室液池中初始動(dòng)量逐漸發(fā)生衰減,最終改變運(yùn)動(dòng)方向而向上反折流動(dòng)并發(fā)生液沫夾帶.
(2) 不同粒徑的顆粒在激冷室流場(chǎng)中的分布不同,粒徑較小的顆粒氣相跟隨性更為明顯、分布更為分散.
(3) 不同粒徑的顆粒主要碰撞區(qū)域不同,粒徑為0.05mm和0.1mm的小尺寸灰渣顆粒碰撞主要發(fā)生在下降管下端;0.5mm的大尺寸灰渣顆粒的碰撞主要發(fā)生在激冷室爐體下部,在設(shè)計(jì)制造過(guò)程中要重點(diǎn)關(guān)注這些位置.
(4) 激冷室內(nèi)各壁面沖蝕、磨蝕破壞機(jī)理不同,下降管下端壁面主要是撞擊磨損;激冷室爐體壁面是沖刷磨損和撞擊磨損的耦合作用.
[1] 龔?欣,劉海峰,王輔臣,等. 新型(多噴嘴對(duì)置式)水煤漿氣化爐[J]. 節(jié)能與環(huán)保,2001(6):15-17.
Gong Xin,Liu Haifeng,Wang Fuchen,et al. A new type(with opposed multi-nozzles) of gasifier for coal-water slurry[J]. Energy Conservation & Environmental Protection,2001(6):15-17(in Chinese).
[2] 張?斌,孔德升,宋兆龍. 四噴嘴氣化工藝技術(shù)優(yōu)化總結(jié)[J]. 煤炭加工與綜合利用,2015(2):57-59,67,16.
Zhang Bin,Kong Desheng,Song Zhaolong. Summarization to techniques of optimizations of four-injector gasify technology[J]. Coal Processing & Comprehensive Utilization,2015(2):57-59,67,16(in Chinese).
[3] 曹孟常. 單噴嘴與多噴嘴水煤漿氣化技術(shù)選擇與對(duì)比[J]. 儀器儀表用戶,2018,25(9):27-30.
Cao Mengchang. The selection and comparison of coal slurry gasification technology between single nozzle and multi-nozzle[J]. Instrumentation,2018,25(9):27-30(in Chinese).
[4] Kurowski M P,SpliethoffH. Deposition and slagging in an entrained-flow gasifier with focus on heat transfer,reactor design and flow dynamics with SPH[J]. Fuel Processing Technology,2016,152:147-155.
[5] Wu Xuan,Li Tie,Yuan Zhulin. Numerical prediction of particle number concentration distribution in scrubbing-cooling chamber of entrained-flow coal gasifier[J]. Chemical Engineering Journal,2009,149(1):325-333.
[6] 吳?晅,李?鐵,蔡?杰,等. 水煤漿氣化爐洗滌室內(nèi)氣體穿越液池過(guò)程顆粒分布的數(shù)值模擬[J]. 中國(guó)電機(jī)工程學(xué)報(bào),2008,38(20):15-21.
Wu Xuan,Li Tie,Cai Jie,et al. Numerical simulation of particles distribution in process of gas crossing cistern in scrubbing chamber in coal water slurry gasifier[J]. Proceedings of the CSEE,2008,38(20):15-21(in Chinese).
[7] 吳?晅,謝海燕,李?鐵,等. 激冷室內(nèi)氣體穿越液池過(guò)程氣液固三相的數(shù)值模擬[J]. 熱能動(dòng)力工程,2007,22(4):385-390.
Wu Xuan,Xie Haiyan,Li Tie,et al. A gas-liquid-solid three-phase numerical simulation of the syngas passing through a cistern in a quench chamber[J]. Journal of Engineering for Thermal Energy and Power,2007,22(4):385-390(in Chinese).
[8] Li C,Dai Z,Xu J. Numerical study of the particle residence time and flow characters in an opposed multi-burner gasifier[J]. Powder Technology,2015,286:64-72.
[9] 姜?峰,王兵兵,齊國(guó)鵬,等. 汽-液-固多管循環(huán)流化床蒸發(fā)器中固體顆粒的分布[J]. 天津大學(xué)學(xué)報(bào)(自然科學(xué)與工程技術(shù)版),2013,46(2):133-137.
Jiang Feng,Wang Bingbing,Qi Guopeng,et al. Solid particle distribution in vapor-liquid-solid multi-pipe circulating fluidized bed evaporator[J]. Journal of Tianjin University(Science and Technology),2013,46(2):133-137(in Chinese).
[10] 田?華,張?釗,陳天宇,等.管排換熱器碳煙顆粒沉積分布特性的數(shù)值模擬[J]. 天津大學(xué)學(xué)報(bào)(自然科學(xué)與工程技術(shù)版),2021,54(8):825-833.
Tian Hua,Zhang Zhao,Chen Tianyu,et al. Numerical simulation on soot particle deposition distribution characteristics of tube heat exchangers[J]. Journal of Tianjin University(Science and Technology),2021,54(8):825-833(in Chinese).
[11] 趙永彬,吳?輝,蔡曉亮,等. 煤氣化殘?jiān)幕咎匦匝芯縖J]. 潔凈煤技術(shù),2015,21(3):110-113,74.
Zhao Yongbin,Wu Hui,Cai Xiaoliang,et al. Basic characteristics of coal gasification residual[J]. Clean Coal Technology,2015,21(3):110-113,74(in Chinese).
[12] 宋瑞領(lǐng),李?靜,付亮亮,等. 多噴嘴對(duì)置式水煤漿氣化爐爐渣特性研究[J].潔凈煤技術(shù),2018,24(5):43-49.
Song RuiLing,Li Jing,F(xiàn)u Liangliang,et al. Characteristics of slags generated from multi-nozzle opposed coal-water slurry gasifier[J]. Clean Coal Technology,2018,24(5):43-49(in Chinese).
[13] 尤學(xué)一,朱生風(fēng),王曉宇,等. 表面波誘導(dǎo)的近底高濃度泥沙水層內(nèi)波動(dòng)場(chǎng)的計(jì)算[J]. 天津大學(xué)學(xué)報(bào),2012,45(1):1-5.
You Xueyi,Zhu shengfeng,Wang Xiaoyu,et al. Wave field analysis of near-bottom water layer of high sediment concentration induced by surface wave[J]. Journal of Tianjin University,2012,45(1):1-5(in Chinese).
[14] 馮惠生,楊?騰,李文秀,等. D-T型雙軸臥式攪拌裝置半釜持液量時(shí)功率特性的數(shù)值模擬[J]. 天津大學(xué)學(xué)報(bào),2011,44(11):1003-1008.
Feng Huisheng,Yang Teng,Li Wenxiu,et al. Numerical simulation of power performances in D-T shape horizontal biaxial stirring tank with half kettle liquid holdup[J]. Journal of Tianjin University,2011,44(11):1003-1008(in Chinese).
[15] 劉麗艷,蘇?桐,郭?凱,等. 壓水堆核電站蒸汽發(fā)生器二次側(cè)兩相流流場(chǎng)特性模擬[J]. 天津大學(xué)學(xué)報(bào)(自然科學(xué)與工程技術(shù)版),2019,52(7):745-753.
Liu Liyan,Su Tong,Guo Kai,et al. Simulation of two-phase flow on the secondary side of PWR steam generator[J]. Journal of Tianjin University(Science and Technology),2019,52(7):745-753(in Chinese).
[16] 郭瓊瓊,文遠(yuǎn)高,夏雨琳,等. 基于DPM模型的建筑小區(qū)內(nèi)顆粒物擴(kuò)散研究[J]. 工業(yè)安全與環(huán)保,2019,45(8):74-79,103.
Guo Qiongqiong,Wen Yuangao,Xia Yulin,et al. Research on particle diffusion of building zone based on DPM[J]. Industrial Safety and Environmental Protec-tion,2019,45(8):74-79,103(in Chinese).
[17] 張?濤,李紅文. 管道復(fù)雜流場(chǎng)氣固兩相流DPM仿真優(yōu)化[J]. 天津大學(xué)學(xué)報(bào)(自然科學(xué)與工程技術(shù)版),2015,48(1):39-48.
Zhang Tao,Li Hongwen. Simulation optimization of DPM on gas-solid two-phase flow in complex pipeline flow Field[J]. Journal of Tianjin University(Science and Technology),2015,48(1):39-48(in Chinese).
[18] 張儷安. 通風(fēng)除塵管道磨損的數(shù)值研究[D]. 馬鞍山:安徽工業(yè)大學(xué)建筑工程學(xué)院,2017.
Zhang Li’an. Numerical Simulation on Erosion of Ventilation and Dust Removal Pipeline[D]. Maanshan:School of Architecture and Civil Engineering,Anhui University of Technology,2017(in Chinese).
Particles Motion and Collision Characteristics of Water-Scrubbing Cooling Chamber in an Opposed Multi-Burner Gasifier
Liu Liyan1, 2,Shi Kai1,Wu Tong1,Tan Wei1,Wang Yang1
(1.School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China;2. Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology,Tianjin 300350,China)
The opposed multi-burner coal-water slurry gasification technology is a clean coal technology independently developed in China,which has the advantages of high conversion rate and high effective gas content. The gasifier is the key equipment for the coal gasification process,which includes a combustion chamber and a water-scrubbing cooling chamber. The syngas generated in the combustion chamber entrained the slag particles into the water-scrubbing cooling chamber,colliding with the gasifier wall under turbulence. The collision caused wear,affecting the safety andlong-term stable operation of the gasifier. This work established a three-dimensional physical model of the water-scrubbing cooling chamber. The VOF multiphase flow model and DPM discrete phase model were used to study the gas-liquid-solid three-phase flow,and the flow field and distribution of particles with different particle sizes were obtained. The collision position and collision parameters between the particles and the furnace body were analyzed by the Fluent UDF,and the dangerous area and failure mechanism were obtained. Results show that the syngas stream generated a negative buoyancy jet in the liquid pool. The momentum of the syngas stream gradually attenuated,and the movement direction changed after. Particles with different sizes had different distributions in the flow field of thewater-scrubbing cooling chamber. Particles with a smaller size had an obvious gas phase follow abilityand a wider distribution range. The size of the particles affects the area where the collision mainly occurred. Particles with sizes of 0.05mm and 0.1mm mainly crashed at the lower end of the dip tube,while the larger particles mainly crashed in the lower part of the furnace body of the water-scrubbing cooling chamber. These positions should be paid attention to during the design and manufacturing process. The damage mechanisms are different in different positions. The damage on the lower wall of the dip tube is mainly impact-wear,while that on the furnace body is mainly the coupling effect of erosive-wear and impact-wear.
opposed multi-burner gasifier;water-scrubbing cooling chamber;slag particles;wear;numerical analysis
10.11784/tdxbz202101005
TQ536.4;TQ133.1
A
0493-2137(2022)04-0343-07
2021-01-05;
2021-01-28.
劉麗艷(1977—??),女,博士,教授,liuliyan@tju.edu.cn.
汪?洋,yangwang2017@tju.edu.cn.
國(guó)家重點(diǎn)研發(fā)計(jì)劃資助項(xiàng)目(2018YFC0808500).
Supported by the National Key Research and Development Program of China(No. 2018YFC0808500).
(責(zé)任編輯:田?軍)