本文關(guān)鍵詞： 濕煙氣 除濕 降膜 CaCl_2溶液 水回收　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：燃煤機(jī)組濕法脫硫后排放的濕煙氣中含有大量水蒸氣,煙氣中水分?jǐn)y帶量約為80g/kg干煙氣,是電廠水資源消耗的重要組成部分,同時(shí)以潛熱的形式排放大量低溫余熱,且引起煙囪腐蝕、"白煙"、煙囪雨等一系列問題。隨著節(jié)水降耗工作的逐步深入,煙氣除濕技術(shù)的研究得到了越來越多的關(guān)注。溶液除濕技術(shù)基于除濕溶液與濕煙氣中水蒸氣分壓力之差,推動水蒸氣在氣相與液相間的遷移,在濕煙氣除濕領(lǐng)域具有較大的應(yīng)用潛力。除濕劑的選擇是影響系統(tǒng)性能和經(jīng)濟(jì)性的關(guān)鍵,結(jié)合濕煙氣除濕的應(yīng)用環(huán)境、各種除濕劑的性能、經(jīng)濟(jì)性等因素分析表明,成本低廉的CaCl2溶液是一種良好的濕煙氣除濕用除濕劑。本文首先通過數(shù)值模擬的方法,初步研究了 CaCl2溶液用于煙氣除濕的性能特點(diǎn)。建立了絕熱型逆流管式降膜除濕過程的控制方程,采用有限差分法,通過數(shù)值計(jì)算的方法,研究了管式降膜除濕器內(nèi)的吸收熱質(zhì)過程,探究了溶液溫度、濃度、雷諾數(shù)、傳質(zhì)面積及煙氣溫度對除濕性能的影響,并分析了液側(cè)與氣側(cè)的變化規(guī)律。計(jì)算表明:基于CaCl2溶液的煙氣除濕工藝可行,除濕效率超過50%,能夠適應(yīng)脫硫后煙氣參數(shù)下的除濕需求。除濕過程中,溶液溫度上升是除濕性能下降的主要因素,主要?dú)庖簜髻|(zhì)阻力在氣側(cè),數(shù)值模擬為進(jìn)一步的試驗(yàn)研究提供了參考。其次,設(shè)計(jì)、搭建了絕熱型管式內(nèi)降膜除濕試驗(yàn)臺,試驗(yàn)研究了 CaCl2溶液的除濕特性,探究了溶液濃度、溫度、傳質(zhì)面積、進(jìn)口煙氣溫度等因素對除濕性能的影響,并與相同狀態(tài)下的清水冷凝除濕進(jìn)行了對比。試驗(yàn)結(jié)果表明:CaCl2溶液除濕效率能夠滿足濕煙氣除濕需求,最大除濕效率可達(dá)70%;各因素對除濕性能的影響與模擬結(jié)果趨勢一致;溶液濃度和溶液溫度是影響除濕效率的關(guān)鍵因素,除濕溶液濃度不宜超過45%,在滿足工程系統(tǒng)經(jīng)濟(jì)性且保證溶液不結(jié)晶的條件下,應(yīng)盡量降低溶液溫度,以提高除濕效率;相對于清水冷凝除濕效率為16.9%-33.9%的工況下,溶液除濕效率達(dá)到40%～55%,且煙氣出口相對濕度約60%,在回收水分的同時(shí)為解決濕煙氣凝結(jié)造成煙囪腐蝕提供了可能。數(shù)據(jù)分析得到,試驗(yàn)工況下傳質(zhì)系數(shù)介于0.009m/s～0.040m/s之間,除濕效率的實(shí)驗(yàn)關(guān)聯(lián)式為η= 467.24Tain0.4805Xin0.841Tsolin-1.843ζlg0.071A0.432,上述結(jié)果為該工藝進(jìn)一步中試研究和應(yīng)用提供了參考。
[Abstract]:The wet flue gas emitted from coal-fired units after wet desulfurization contains a large amount of water vapor, and the moisture carrying capacity in the flue gas is about 80g / kg dry flue gas, which is an important part of water resources consumption in power plants. At the same time, a large amount of low temperature waste heat is discharged in the form of latent heat, which causes a series of problems such as chimney corrosion, "white smoke", chimney rain and so on. More and more attention has been paid to the research of flue gas dehumidification technology. Solution dehumidification technology is based on the difference of water vapor partial pressure between dehumidification solution and wet flue gas, which promotes the migration of water vapor between gas phase and liquid phase. The selection of dehumidifier is the key to affect the performance and economy of the system. Combined with the application environment of wet flue gas dehumidification, the performance of various dehumidifiers. Economic analysis shows that the low-cost CaCl2 solution is a good dehumidifier for wet flue gas dehumidification. The performance characteristics of CaCl2 solution used in flue gas dehumidification were studied preliminarily. The governing equation of adiabatic countercurrent tube falling film dehumidification process was established. The finite difference method was adopted and the numerical calculation method was used. The absorption process of heat and mass in the tube dehumidifier was studied. The effects of solution temperature, concentration, Reynolds number, mass transfer area and flue gas temperature on the dehumidification performance were investigated. The results show that the dehumidification process based on CaCl2 solution is feasible and the dehumidification efficiency is more than 50%. In the process of dehumidification, the increase of solution temperature is the main factor to decrease the dehumidification performance, and the main gas-liquid mass transfer resistance is on the gas side. Numerical simulation provides a reference for further experimental research. Secondly, the adiabatic tube internal falling film dehumidification test rig is designed and built. The dehumidification characteristics of CaCl2 solution are experimentally studied and the solution concentration is investigated. The influence of temperature, mass transfer area and inlet flue gas temperature on the dehumidification performance. The experimental results show that the dehumidification efficiency of the solution of 1% CaCl 2 can meet the demand of dehumidification of wet flue gas, and the maximum dehumidification efficiency can reach 70%. The influence of various factors on the dehumidification performance is consistent with the trend of simulation results. Solution concentration and solution temperature are the key factors affecting the dehumidification efficiency. The concentration of dehumidified solution should not exceed 455.The solution temperature should be reduced as far as possible under the condition of satisfying the economy of the engineering system and ensuring the solution not crystallizing. To improve dehumidification efficiency; Under the condition that the dehumidification efficiency of water is 16.9- 33.9%, the solution dehumidification efficiency reaches 40% and 55%, and the relative humidity of flue gas outlet is about 60%. It is possible to recover moisture and solve the corrosion of chimney caused by wet flue gas condensation. According to the data analysis, the mass transfer coefficient is between 0.009 m / s and 0.040 m / s under the test condition. The experimental correlation of dehumidification efficiency is 畏 = 467.24 Tain0.4805 Xin0.841 Tsolin-1.843 味 lg0.071A0.432. These results provide a reference for further pilot study and application of this process.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X773

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