【摘要】：霧霾已成為我國北方冬季揮之不去的陰影,嚴(yán)重影響人們的身心健康,燃煤排放是造成霧霾的罪魁禍?zhǔn)字�。雖然煤炭燃燒污染物減排機(jī)理研究已非常成熟,各種減排措施也較為完善,但是在具體實(shí)施過程中卻不盡人意,究其緣由,主要是減排工藝研究和實(shí)施過程不夠精致,再加之系統(tǒng)穩(wěn)定性不高,造成污染物超標(biāo)排放。本文針對(duì)20余處火電廠燃煤鍋爐煙氣超低排放工程實(shí)施案例中抽化出的共性工藝及系統(tǒng)可靠性問題進(jìn)行研究,主要研究內(nèi)容如下：(1)在SCR脫硝系統(tǒng)中首層催化劑入口處煙氣流場和氨濃度分布情況是影響脫硝效率的關(guān)鍵因素,為提高其煙氣流場和氨濃度的均勻性,需對(duì)AIG上游的煙道進(jìn)行優(yōu)化設(shè)計(jì)。本文基于CFD數(shù)值模擬結(jié)合工程案例對(duì)AIG上游異徑煙道內(nèi)的不同導(dǎo)流板布置進(jìn)行研究得到優(yōu)化煙道布置方案,針對(duì)異徑煙道需在其入口、出口布置非均勻?qū)Я靼?在其上游添加直型引流板、下游添加直型整流板,確定額定煙氣量下導(dǎo)流板位置、結(jié)構(gòu)、尺寸等的優(yōu)化配置方案。(2)在SCR脫硝過程中使煙氣溫度保持在催化劑最佳活性溫度窗口是延長催化劑壽命和提高脫硝效率的有效方式,為此需保持煙氣溫度并使流場分布均勻。本文基于CFD數(shù)值模擬分析,通過設(shè)置省煤器高溫段煙氣旁路,將高溫?zé)煔馀c省煤器出口低溫?zé)煔饣旌?使混合煙氣的溫度達(dá)到催化劑的最佳反應(yīng)溫度區(qū)間。旁路煙道與主煙道的接口布置形式,是高低溫?zé)煔獬浞只旌系年P(guān)鍵。通過對(duì)包括圓柱形旁路煙道插入主煙道方案、矩形旁路煙道插入主煙道方案、文丘里喉管方案、靜壓箱方案等典型布置方案進(jìn)行大量數(shù)值模擬研究,借鑒“靜壓箱”原理,確定了主煙道接口處上側(cè)、左右兩側(cè)布置與旁路煙道等高“∏”形靜壓箱煙道方案。(3)在濕法脫硫系統(tǒng)中維持煙氣與漿液“氣-液”平衡是提高脫硫效率的關(guān)鍵控制要素,本文基于CFD數(shù)值模擬,對(duì)脫硫系統(tǒng)及內(nèi)部構(gòu)件進(jìn)行優(yōu)化設(shè)計(jì),研究設(shè)置漿池分區(qū)裝置、湍流強(qiáng)化裝置、塔壁增效裝置,并對(duì)脫硫塔內(nèi)部的氣液兩相流動(dòng)情況進(jìn)行數(shù)值模擬,實(shí)現(xiàn)脫硫系統(tǒng)的勻質(zhì)增效。數(shù)值模擬結(jié)果顯示,脫硫塔內(nèi)開啟噴淋后在湍流強(qiáng)化裝置、塔壁增效裝置和噴淋層的聯(lián)合作用下,消除了煙氣偏流現(xiàn)象,實(shí)現(xiàn)了煙氣流場的均布。(4)為保障脫硫系統(tǒng)可靠運(yùn)行,需在脫硫塔入口設(shè)置保護(hù)措施,防止因煙氣溫度突升燒毀脫硫系統(tǒng)。本文基于CFD數(shù)值模擬,建立包含減溫水噴射、湍流混合、傳熱傳質(zhì)等過程的數(shù)值模擬方法,通過計(jì)算分析煙道內(nèi)噴水冷卻后的煙氣溫度分布情況,確定噴嘴的最優(yōu)布置形式,保障脫硫系統(tǒng)的可靠達(dá)標(biāo)運(yùn)行。(5)超低排放系統(tǒng)各處理單元之間的聯(lián)絡(luò)煙道內(nèi)的流場特性對(duì)其下游處理單元的達(dá)標(biāo)提效具有重要影響。引風(fēng)機(jī)出口至WGGH間聯(lián)絡(luò)煙道(方圓節(jié)煙道)加裝導(dǎo)流板后換熱管區(qū)域煙氣充滿度大幅提高使得換熱效果達(dá)到設(shè)計(jì)要求。脫硫塔出口至濕式靜電除塵器入口間聯(lián)絡(luò)煙道(雙向異徑煙道)加導(dǎo)流板后使得WESP極板區(qū)域煙氣分布均勻,工程應(yīng)用中應(yīng)對(duì)WESP入口煙氣均布偏差系數(shù)和氣流方向性均做考察�；趨f(xié)同理論系統(tǒng)考慮減排要素,基于大量工程案例不斷優(yōu)化設(shè)計(jì)各子系統(tǒng)及各組件并進(jìn)行系統(tǒng)優(yōu)化配置,對(duì)各工程進(jìn)行實(shí)地測量驗(yàn)證設(shè)計(jì)方案,通過對(duì)所測數(shù)據(jù)進(jìn)行橫向、縱向綜合分析總結(jié)規(guī)律發(fā)現(xiàn)問題,以反饋至下個(gè)工程方案的設(shè)計(jì)再優(yōu)化,不斷改進(jìn),在周而復(fù)始過程中力求極致。本文研究成果已在20余個(gè)燃煤電廠的大氣污染物處理工程得到應(yīng)用,系統(tǒng)運(yùn)行平穩(wěn),各項(xiàng)指標(biāo)達(dá)到預(yù)期要求。該研究方案在山西某電廠#1機(jī)組超低排放改造工程得到實(shí)施。據(jù)《山西某電廠#1機(jī)組廢氣污染源現(xiàn)狀監(jiān)測報(bào)告》報(bào)告顯示NOx排放濃度在10～14mg/Nm3,SO2排放濃度在16-19mg/Nm3。研究表明,本文研究成果經(jīng)得起工程檢驗(yàn),各項(xiàng)指標(biāo)均達(dá)到《火電廠大氣污染物排放標(biāo)準(zhǔn)》(GB13223-2011)所規(guī)定的燃?xì)鈾C(jī)組排放限值,實(shí)現(xiàn)了超低排放。
[Abstract]:Haze has become the shadow of winters in the north of China, which seriously affects people's physical and mental health. Coal emission is one of the leading causes of fog and haze. Although the mechanism of coal combustion pollutant emission reduction is very mature and various measures are more perfect, but in the implementation process, it is not satisfactory. The main reason is the reason. The research and implementation process of the emission reduction technology is not delicate, and the system stability is not high, and the pollutant discharge is exceeding the standard. In this paper, the common process and system reliability problems extracted from more than 20 coal-fired boiler flue gas ultra low emission projects in thermal power plants are studied. The main contents are as follows: (1) the SCR denitrification system The flue gas flow field and the concentration distribution of ammonia at the entrance of the middle first layer of catalyst are the key factors affecting the denitrification efficiency. In order to improve the flue gas flow field and the uniformity of ammonia concentration, the optimization design of the flue of the upstream of AIG is needed. Based on the CFD numerical simulation combined with the project case, the layout of different diversion plates in the upstream different diameter flue of AIG is studied. In order to optimize the layout scheme of flue gas channel, the non uniform flow plate is arranged in the outlet, the outlet is arranged in the outlet, the direct type drainage plate is added to its upstream, the straight rectifying plate is added to the downstream, the optimal configuration of the diversion plate position, structure and size under the rated flue gas amount is determined. (2) the flue gas temperature is kept in the catalyst most during the SCR denitrification process. The good active temperature window is an effective way to prolong the life of the catalyst and improve the denitrification efficiency. Therefore, it is necessary to keep the temperature of the flue gas and make the distribution of the flow field evenly distributed. Based on the CFD numerical simulation analysis, the flue gas of the high temperature section of the economizer is mixed with the low temperature flue gas at the exit of the economizer to make the temperature of the mixed flue gas catalyze. The optimum reaction temperature range of the agent, the layout of the interface between the bypass flue and the main flue, is the key to the full mixing of the high and low temperature flue gas. A large number of typical layout schemes, including the main flue, the rectangular bypass flue into the main flue, the Venturi throat scheme and the static pressure box scheme, are numerically simulated. Based on the principle of "static pressure box", this paper determines the upper side of the main flue interface, the layout of the left and right sides and the bypass flue. (3) to maintain the gas liquid balance between the flue gas and the slurry in the wet desulphurization system is the key control factor to improve the desulfurization efficiency. Based on the CFD numerical simulation, the desulfurization system and the desulfurization system are used in this paper. The internal components are optimized, the partition device of the slurry pool, the turbulence intensifying device, the tower wall synergistic device, and the numerical simulation of the gas-liquid two phase flow in the desulfurization tower are simulated to achieve the uniformity and efficiency of the desulfurization system. The numerical simulation results show that the turbulence intensification device, the tower wall synergist and the spray in the desulphurization tower are opened in the desulphurization tower. In order to ensure the reliable operation of the desulfurization system, the protection measures should be set up at the entrance of the desulphurization tower to prevent the desulphurization system from burning up because of the temperature rise of the flue gas. Based on the CFD numerical simulation, this paper establishes the process of setting up the heat and mass transfer process including the cooling water jet, the turbulence mixing and the heat and mass transfer. The numerical simulation method, through the calculation and analysis of the distribution of the flue gas temperature after the water spray cooling in the flue, determines the optimal arrangement of the nozzle, and ensures the reliable operation of the desulfurization system. (5) the flow field characteristics in the contact flue between the treatment units of the ultra low emission system have an important influence on the efficiency of the downstream processing unit. After the outlet of the air blower to the contact pipe between the WGGH and the pipe (the square section flue), the heat transfer effect reaches the design requirement after the diversion plate is added to the diversion plate, which makes the heat exchange effect reach the design requirements. The flue gas distribution in the WESP plate area is evenly distributed after the exit of the desulfurizer outlet to the inlet of the wet electrostatic precipitator entrance (two way flue) and the diversion plate, and the engineering application is applied. On the basis of a large number of engineering cases, we should optimize the design of the subsystems and components and optimize the system configuration based on a large number of engineering cases. Based on a large number of engineering cases, we carry out a field measurement verification plan for each project, through the horizontal and longitudinal measurements of the measured data. The research results have been applied in the air pollutant treatment project of more than 20 coal-fired power plants, and the system runs smoothly and the targets have reached the expected requirements. The research scheme is in the mountain. The ultra low emission transformation project of #1 unit of a power plant in a power plant is implemented. According to the report of the status monitoring report of the exhaust gas pollution source of the #1 unit in a power plant in Shanxi, the emission concentration of NOx is from 10 to 14mg/Nm3, and the SO2 emission concentration in the 16-19mg/Nm3. study shows that the results of this study can stand the engineering test, and all the indexes have reached the emission of the air pollutants in the thermal power plant. The emission limits of gas generating units stipulated in standard (GB13223-2011) have achieved ultra-low emission.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：X773

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