發(fā)布時(shí)間：2018-03-21 00:37

  本文選題：水化　切入點(diǎn)：超聲波　出處：《大連海事大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：大氣二氧化硫污染是亟待解決的環(huán)境問題,濕法脫硫是當(dāng)前應(yīng)用最為廣泛的脫硫方法,其中鎂法脫硫是具有發(fā)展前景的技術(shù)手段。鎂法脫硫以氫氧化鎂為脫硫劑,其制備方法以氧化鎂水化法為主。傳統(tǒng)氧化鎂水化制備氫氧化鎂技術(shù)擁有反應(yīng)時(shí)間長、水化效率低、最終水化率不高、設(shè)備占地大等缺陷。目前國內(nèi)外圍繞如何改進(jìn)水化制備氫氧化鎂技術(shù)展開研究,其中針對(duì)水化過程施加高溫高壓反應(yīng)條件能有效提升水化效率,但反應(yīng)過程不夠溫和,難以細(xì)微調(diào)控相關(guān)參數(shù)。超聲波空化效應(yīng)能在液相中產(chǎn)生局部高溫高壓反應(yīng)條件,因此超聲波協(xié)助水化技術(shù)具有重要研究?jī)r(jià)值。本文以機(jī)械攪拌水化法為基礎(chǔ),增加超聲處理設(shè)備,改進(jìn)傳統(tǒng)水化制備氫氧化鎂法。首先,比較了氧化鎂在機(jī)械攪拌水化和超聲水化反應(yīng)條件下的效果,設(shè)計(jì)實(shí)驗(yàn)研究了兩種反應(yīng)條件下水化時(shí)間、水化溫度同氧化鎂水化率、水化速率的關(guān)系。其次,以反應(yīng)動(dòng)力學(xué)為基礎(chǔ)分析了兩種反應(yīng)條件下的水化率變化,并利用相關(guān)水化動(dòng)力學(xué)模型對(duì)實(shí)驗(yàn)數(shù)據(jù)進(jìn)行擬合分析。最后,對(duì)水化后的樣品進(jìn)行表征測(cè)試,利用SEM、XRD、TGA、FTIR等技術(shù)分析了兩種反應(yīng)條件下水化產(chǎn)物的形貌特征、成分變化、晶型結(jié)構(gòu)和水化率差異原因,并據(jù)此推導(dǎo)超聲波提升水化反應(yīng)機(jī)制,即:超聲波空化效應(yīng)所產(chǎn)的微射流和局部高溫高壓環(huán)境使氧化鎂表水化產(chǎn)生的氫氧化鎂沉淀剝落,裸露的氧化鎂繼續(xù)參與反應(yīng),從而提升了水化率和水化效率。最后得出結(jié)論：超聲波對(duì)水化反應(yīng)制備氫氧化鎂脫硫劑具有促進(jìn)作用,隨超聲時(shí)間增長,反應(yīng)溫度的提升,其水化率和水化效率同機(jī)械攪拌相比明顯提升。氧化鎂初始濃度為1%,反應(yīng)溫度為338K,一個(gè)標(biāo)準(zhǔn)大氣壓下,反應(yīng)時(shí)間2h,機(jī)械攪拌水化率46%,超聲水化率71%。
[Abstract]:Atmospheric sulfur dioxide pollution is an urgent environmental problem, and wet desulfurization is the most widely used desulphurization method, among which magnesium desulfurization is a promising technology. Magnesium hydroxide is used as desulfurization agent in magnesium desulphurization. The traditional method of magnesium oxide hydration to prepare magnesium hydroxide has long reaction time, low hydration efficiency and low hydration rate. At present, the domestic and international research on how to improve the hydration technology for the preparation of magnesium hydroxide has been carried out, in which the application of high temperature and high pressure reaction conditions to the hydration process can effectively improve the hydration efficiency, but the reaction process is not mild enough. The ultrasonic cavitation effect can produce local high temperature and high pressure reaction conditions in liquid phase, so ultrasonic assisted hydration technology has important research value. Adding ultrasonic treatment equipment to improve the traditional method of hydration to prepare magnesium hydroxide. Firstly, the effect of magnesium oxide in mechanical agitation hydration and ultrasonic hydration reaction was compared, and the hydration time of two reaction conditions was designed and studied. The relationship between the hydration temperature and the hydration rate and the hydration rate of magnesium oxide. Secondly, based on the reaction kinetics, the variation of the hydration rate under the two reaction conditions was analyzed, and the experimental data were fitted and analyzed by using the relevant hydration kinetics model. The hydrated samples were characterized and tested, and the morphology, composition, crystal structure and hydration rate of the hydrated products were analyzed by means of SEMXRDX TGAIR and other techniques, and the mechanism of ultrasonic enhancement of hydration reaction was deduced based on the analysis of the morphology, composition change, crystal structure and hydration rate of the hydrated products. That is, the micro jet produced by ultrasonic cavitation and local high temperature and high pressure environment make magnesium hydroxide precipitate and exfoliate from the hydration of magnesium oxide, and the exposed magnesium oxide continues to participate in the reaction. Finally, it is concluded that ultrasonic can promote the preparation of magnesium hydroxide desulfurizer by hydration reaction, and the reaction temperature increases with the increase of ultrasonic time. The initial concentration of magnesium oxide is 1, the reaction temperature is 338K, the reaction time is 2 h, the hydration rate of mechanical stirring is 46 and the ultrasonic hydration rate is 71.
【學(xué)位授予單位】：大連海事大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X701.3

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本文編號(hào)：1641495