本文關(guān)鍵詞：多孔碳化硅陶瓷表面改性及其煙氣過濾性能研究　出處：《長安大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 多孔碳化硅 表面改性 晶須制備 過濾性能

【摘要】：近年來霧霾天氣成為人們關(guān)注的熱點,而霾的核心物質(zhì)是沉積在空氣中的灰,煙塵等顆粒物,且極易吸入人體肺部產(chǎn)生危害。而柴油車產(chǎn)生的尾氣主要以碳顆粒為主,是造成霧霾天氣的一個主要成因。目前柴油車尾氣處理方式主要依靠壁流式過濾器捕集顆粒物,而柴油車運行工況復雜,排放尾氣溫度較高,因此要求過濾壁具有耐高溫,抗氧化,耐腐蝕等優(yōu)良特性,而多孔碳化硅陶瓷因其優(yōu)異獨特的性能成了過濾材料的熱門選擇,并成為材料學領(lǐng)域的研究熱點。其原料來源廣泛,成本低廉,傳統(tǒng)制備方法多樣。本文利用木材的天然多孔結(jié)構(gòu),以櫸木為模板采用液態(tài)硅浸漬的獨特方法制備生物形態(tài)多孔碳化硅陶瓷,所得產(chǎn)物性能優(yōu)異,具有良好的孔隙結(jié)構(gòu),在節(jié)能減排方面具有很大優(yōu)勢,但其在過濾超細顆粒時仍存在一些局限,當生物形態(tài)碳化硅過濾納米級別顆粒物時,高的孔隙度可以有效地捕集微小顆粒物,但同時造成通透性減小,發(fā)動機排氣背壓升高,減小其壽命。因此制備出通透性良好且捕集效率高的多孔碳化硅將成為我們重點解決的問題。故而本研究通過模擬人的呼吸系統(tǒng),仿生設(shè)計合成類似支氣管表層的纖毛狀微觀結(jié)構(gòu),采用熔鹽法和溶膠-凝膠法對多孔碳化硅陶瓷表面進行改性處理,分別利用熔鹽化學反應(yīng)和溶膠-凝膠制備工藝在碳化硅陶瓷孔隙中生長出莫來石和硼酸鋁晶須,通過各種表征手段發(fā)現(xiàn)良好的晶須形貌生長在碳化硅基質(zhì)上。為了測試改性材料的過濾性能,又搭建了柴油燃燒煙氣過濾測試平臺,保持通入的空氣流量恒定,控制溫度小幅度變化,分別測試空白顆粒物濃度、柴油燃燒煙氣顆粒物濃度、煙氣經(jīng)過碳化硅陶瓷過濾的顆粒物濃度、經(jīng)過碳化硅/莫來石的顆粒物濃度,將對照實驗數(shù)據(jù)進行對比分析,獲得過濾性能與微觀結(jié)構(gòu)之間的構(gòu)效關(guān)系,柴油煙氣經(jīng)過改性后的碳化硅/莫來石材料過濾,測得的顆粒物濃度值明顯降低,表明改性后制備的莫來石晶須結(jié)構(gòu)的多孔陶瓷對顆粒物的捕集過濾性能強于改性之前,也為后期的改性實驗做出了引導。
[Abstract]:In recent years, haze weather has become the focus of attention, and the core matter of haze is ash, smoke and other particulates deposited in the air. And easily inhaled the human lungs to cause harm, and diesel vehicle emissions are mainly carbon particles. At present, diesel vehicle exhaust gas treatment mainly depends on wall flow filter to capture particulate matter, while diesel vehicle operating condition is complex, exhaust gas temperature is higher. Therefore, filtration wall is required to have excellent properties such as high temperature resistance, oxidation resistance, corrosion resistance and so on. Porous silicon carbide ceramics have become the hot choice of filtration materials because of its excellent and unique properties. It has become a research hotspot in the field of materials science. Its raw materials are widely available, the cost is low, and the traditional preparation methods are various. In this paper, the natural porous structure of wood is used. Biologically porous silicon carbide ceramics were prepared by liquid silicon impregnation with beech as template. The obtained products have excellent properties and good pore structure, and have great advantages in energy saving and emission reduction. However, there are still some limitations in the filtration of ultrafine particles. When nano-sized particles are filtered by biomorphic silicon carbide, high porosity can effectively capture micro-particles, but at the same time, reduce the permeability. Therefore, the preparation of porous silicon carbide with good permeability and high trapping efficiency will be a key problem for us to solve. Therefore, this study simulates the respiratory system of human beings. The ciliated microstructure similar to the bronchial surface was synthesized by bionic design. The porous silicon carbide ceramic surface was modified by molten salt method and sol-gel method. Mullite and aluminum borate whiskers were grown in the pores of silicon carbide ceramics by molten salt chemical reaction and sol-gel preparation respectively. In order to test the filtration performance of the modified materials, a diesel combustion flue gas filtration test platform was set up to keep the air flow rate constant. The concentration of blank particles, the concentration of particulate matter from diesel combustion smoke, the concentration of particulate matter filtered by sic ceramic, and the concentration of particulate matter through silicon carbide / mullite were measured respectively by controlling the small change of temperature. By comparing and analyzing the experimental data, the structure-activity relationship between filtration performance and microstructure was obtained. After modified sic / mullite filter, the measured concentration of particulate matter was obviously decreased. The results showed that the porous ceramics with mullite whisker structure prepared after modification were better than those before modification in the trapping and filtration of particulate matter, and also provided guidance for the later modification experiment.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X701

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本文編號：1403299