中国电机工程学报
中國電機工程學報
중국전궤공정학보
ZHONGGUO DIANJI GONGCHENG XUEBAO
2013年
29期
39-48
,共10页
钱达蔚%张吉超%关梦龙%熊源泉
錢達蔚%張吉超%關夢龍%熊源泉
전체위%장길초%관몽룡%웅원천
气液两相流%撞击流%尿素水溶液%氮氧化物吸收%同时脱硫脱硝%三维数值模拟
氣液兩相流%撞擊流%尿素水溶液%氮氧化物吸收%同時脫硫脫硝%三維數值模擬
기액량상류%당격류%뇨소수용액%담양화물흡수%동시탈류탈초%삼유수치모의
gas-liquid two-phase flows%impinging streams%aqueous urea solution%NOx absorption%simultaneous desulfuri-zation and denitrification%3-D numerical simulation
该文建立了撞击流吸收器湿法同时脱硫脱硝化学反应与气液两相流动的三维数学模型。数值模拟采用双欧拉法对吸收器中气液两相流的流动特性进行描述,并通过双膜理论耦合了相关的化学反应。模拟计算发现:气相流场呈“镜像”对称分布;撞击面两侧存在4个烟气流线密集且对称反向螺旋上升的旋流柱;撞击区范围内存在很大的压力梯度和速度梯度,撞击中心处气相的静压力达到最大值;(NH4)2SO3在加速管内的流动过程中迅速生成,而部分接近液相主流区的(NH4)2SO3逐渐被氧化成(NH4)2SO4,脱硫效率达96.8%;同时发现,加速管内NO的浓度则几乎不变。SO2和NO浓度在撞击区内迅速降低,NO吸收反应(包括与(NH4)2SO3的协同反应)大部分发生在撞击区内,尿素对 HNO2具有明显还原分解作用。反应器内氮氧化物中氮元素在脱硝后的主要赋存形态是NO3?,无添加剂条件下脱硝效率达49.2%。
該文建立瞭撞擊流吸收器濕法同時脫硫脫硝化學反應與氣液兩相流動的三維數學模型。數值模擬採用雙歐拉法對吸收器中氣液兩相流的流動特性進行描述,併通過雙膜理論耦閤瞭相關的化學反應。模擬計算髮現:氣相流場呈“鏡像”對稱分佈;撞擊麵兩側存在4箇煙氣流線密集且對稱反嚮螺鏇上升的鏇流柱;撞擊區範圍內存在很大的壓力梯度和速度梯度,撞擊中心處氣相的靜壓力達到最大值;(NH4)2SO3在加速管內的流動過程中迅速生成,而部分接近液相主流區的(NH4)2SO3逐漸被氧化成(NH4)2SO4,脫硫效率達96.8%;同時髮現,加速管內NO的濃度則幾乎不變。SO2和NO濃度在撞擊區內迅速降低,NO吸收反應(包括與(NH4)2SO3的協同反應)大部分髮生在撞擊區內,尿素對 HNO2具有明顯還原分解作用。反應器內氮氧化物中氮元素在脫硝後的主要賦存形態是NO3?,無添加劑條件下脫硝效率達49.2%。
해문건립료당격류흡수기습법동시탈류탈초화학반응여기액량상류동적삼유수학모형。수치모의채용쌍구랍법대흡수기중기액량상류적류동특성진행묘술,병통과쌍막이론우합료상관적화학반응。모의계산발현:기상류장정“경상”대칭분포;당격면량측존재4개연기류선밀집차대칭반향라선상승적선류주;당격구범위내존재흔대적압력제도화속도제도,당격중심처기상적정압력체도최대치;(NH4)2SO3재가속관내적류동과정중신속생성,이부분접근액상주류구적(NH4)2SO3축점피양화성(NH4)2SO4,탈류효솔체96.8%;동시발현,가속관내NO적농도칙궤호불변。SO2화NO농도재당격구내신속강저,NO흡수반응(포괄여(NH4)2SO3적협동반응)대부분발생재당격구내,뇨소대 HNO2구유명현환원분해작용。반응기내담양화물중담원소재탈초후적주요부존형태시NO3?,무첨가제조건하탈초효솔체49.2%。
A 3-D numerical model was used to investigate the effect of simultaneous desulfurization and denitrification by wet process in an impinging stream absorber. The numerical model was based on the Euler-Euler method, and the two-film theory was introduced to couple the chemical absorption reactions of SO2 and NOx. It is found that gas flow shows“mirror” distribution and there are four dense symmetric reverse spiral cyclone columns on both sides of impinging surface. It also shows that the gas flow has large static pressure gradient and x-axial velocity gradient in the impinging area, and the static pressure reaches its maximum value in the centre of the impinging area. In the accelerating tube, (NH4)2SO3 generates immediately, and part of it close to the main liquid flow is gradually oxidized to (NH4)2SO4. The efficiency of desulfurization reaches 96.8%. The concentration of NO remains nearly unchanged in the accelerating tube. The concentration of both SO2 and NO drops sharply, and denitrification reaction (including the reaction with (NH4)2SO3) takes place mainly in the impinging area. Urea exhibits an enhanced effect on reducing HNO2. The nitrogen element from NOx mainly turns into NO3? in liquid phase after the denitrification process. The simulation result shows that the efficiency of denitrification reaches 49.2%without catalyzer.