本文選題：透氧膜　切入點(diǎn)：摻雜　出處：《上海大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：混合離子-電子導(dǎo)體鈣鈦礦型透氧膜(MIEC)主要應(yīng)用在高溫氣體分離和膜催化反應(yīng)中。在一定溫度及氧勢(shì)梯度作用下,空氣中的氧會(huì)以氧離子形式從高壓氧側(cè)通過(guò)氧空位遷移到低壓氧側(cè),如果將透氧膜反應(yīng)器與整體煤氣化聯(lián)合循環(huán)發(fā)電系統(tǒng)耦聯(lián),一方面可以通過(guò)向化石燃料提供高純氧促進(jìn)富氧燃燒,提高能量利用效率,另一方面可以降低生產(chǎn)成本,且有利于CO2的捕獲和存儲(chǔ)。理想透氧膜材料不僅需要較高的透氧量,同時(shí)還應(yīng)兼具良好的結(jié)構(gòu)穩(wěn)定性和優(yōu)異的化學(xué)穩(wěn)定性能。然而,對(duì)于該技術(shù)的實(shí)際生產(chǎn)應(yīng)用來(lái)說(shuō),在高濃度CO2氣氛下工作的透氧膜材料容易受CO2的毒化腐蝕,進(jìn)而影響膜材料的透氧率和穩(wěn)定性。因此,開(kāi)發(fā)抗CO2腐蝕性能的混合導(dǎo)體透氧膜材料是實(shí)現(xiàn)富氧燃燒及整體煤氣化聯(lián)合循環(huán)發(fā)電技術(shù)高效應(yīng)用的基礎(chǔ)和前提。本文以具有高離子電導(dǎo)率和高透氧能力的Ba Co0.88Nb0.12O3-δ(BCN)材料作為研究基礎(chǔ),對(duì)BCN材料在A位和B位進(jìn)行元素?fù)诫s替代,并采用固相反應(yīng)合成制備透氧膜材料Ba1-x Lax Co0.88Nb0.12O3-δ(BLCN)及Ba0.8La0.2Co0.88-x Fex Nb0.12O3-δ(BLCFN),探究元素?fù)诫s替代對(duì)BCN材料的透氧性能、透氧速控步驟、結(jié)構(gòu)穩(wěn)定性等方面的影響。研究發(fā)現(xiàn),在850°C下,BLCN材料隨著La摻雜量增加透氧量逐漸降低。供氧側(cè)通入不同濃度O2時(shí),透氧量隨氧氣濃度的增加而增加。通過(guò)Wagner公式進(jìn)行數(shù)據(jù)擬合得到參數(shù)0n0.5,表明其透氧控制步驟主要由表面交換和體相擴(kuò)散控制。對(duì)于BLCN材料,在850°C下經(jīng)不同濃度CO2氣氛吹掃一定時(shí)間后,XRD結(jié)果顯示BLCN膜材料的結(jié)構(gòu)穩(wěn)定性隨La摻雜量的提高而增強(qiáng)。在5%CO2吹掃下,BLCN材料表面均無(wú)明顯碳酸鹽生成,在純CO2氣體吹掃下,La摻雜含量較低的膜片表面有少量碳酸鹽生成,而摻雜含量較高的BLCN膜材料在5 h后仍未發(fā)生明顯變化,在靜態(tài)CO2氣氛條件下表現(xiàn)出了優(yōu)異的抗CO2腐蝕性能。進(jìn)一步探究BLCN膜材料的透氧能力發(fā)現(xiàn),純CO2氣氛吹掃后,La含量的增加使得膜片抗CO2腐蝕能力增強(qiáng)。其中,BCN及低La摻雜的BLCN(x≤0.2)來(lái)說(shuō),透氧率很快下降為0,而B(niǎo)LCN-0.5膜材料透氧量由CO2切換前的0.67m L·cm-2·min-1逐漸穩(wěn)定在0.46 m L·cm-2·min-1。BLCN膜片抗CO2腐蝕能力的提高主要?dú)w因?yàn)長(zhǎng)a含量增加后金屬-氧鍵能的提高和更穩(wěn)定的鈣鈦礦結(jié)構(gòu)。為了進(jìn)一步改善BLCN膜材料抗CO2腐蝕性能,在BLCN-0.2的基礎(chǔ)上通過(guò)B位摻雜一定比例的Fe元素制備Ba0.8La0.2Co0.88-x Fex Nb0.12O3-δ(BLCFN)透氧膜。結(jié)果顯示,靜態(tài)條件下,在850°C下純CO2分別吹掃5 h后BLCFN材料均未生成明顯的碳酸鹽。與BLCN相比,同等條件下BLCFN表現(xiàn)出了更強(qiáng)的抗CO2腐蝕能力。BLCFN-0.2膜片在900°C下經(jīng)純CO2氣氛吹掃110 h后透氧量由0.96m L·cm-2·min-1,下降并穩(wěn)定在0.31 m L·cm-2·min-1。表明A位基礎(chǔ)上對(duì)B位進(jìn)行Fe元素的摻雜更加有利于透氧膜片在CO2氣氛下的長(zhǎng)期透氧穩(wěn)定性能。
[Abstract]:Mixed ion-electron conductor perovskite-type oxygen permeable membrane (MIEC) is mainly used in high temperature gas separation and membrane catalytic reaction. Oxygen in the air will migrate from the hyperbaric oxygen side through the oxygen vacancy to the low pressure oxygen side in the form of oxygen ions. If the oxygen permeable membrane reactor is coupled to the integrated coal gasification combined cycle power generation system, On the one hand, it can promote oxygen-enriched combustion by providing high purity oxygen to fossil fuels and improve energy utilization efficiency. On the other hand, it can reduce the production cost and be beneficial to the capture and storage of CO2. At the same time, it should also have good structural stability and excellent chemical stability. However, for the practical application of this technology, the oxygen permeable membrane materials working in high concentration CO2 atmosphere are vulnerable to CO2 poisoning corrosion. Thus, the oxygen permeability and stability of the membrane materials are affected. The development of mixed conductor oxygen permeable film with CO2 corrosion resistance is the basis and prerequisite for the efficient application of oxygen-enriched combustion and integrated coal gasification combined cycle power generation technology. This paper deals with Ba Co 0.88 NB 0.12 O 3- 未 BCNs with high ionic conductivity and high oxygen permeability. Materials as a basis for research, The oxygen permeable membrane materials Ba1-x Lax Co 0.88 NB 0.12 O 3- 未 and Ba0.8La0.2Co0.88-x Fex NB 0.12 O 3- 未 were prepared by solid state reaction. The oxygen permeability and oxygen permeability of BCN materials were investigated. It is found that the oxygen permeability of BLCN decreases with the increase of La doping at 850 擄C, and when oxygen supply side passes through the oxygen supply side with different concentrations of O2, The oxygen permeation rate increases with the increase of oxygen concentration. The parameter 0n0.5 is obtained by fitting the data from Wagner formula, which indicates that the oxygen permeation control step is mainly controlled by surface exchange and bulk diffusion. For BLCN materials, The results showed that the structural stability of BLCN films increased with the increase of La doping content after blowing in different concentration of CO2 atmosphere for a certain time at 850 擄C. there was no obvious carbonate formation on the surface of BLCN films swept by 5CO 2. A small amount of carbonate was formed on the surface of the film with low La doping content in pure CO2 gas swept down, while the BLCN film material with high doping content did not change obviously after 5 h. Under the condition of static CO2 atmosphere, the excellent corrosion resistance to CO2 was demonstrated. Further study was made on the oxygen permeability of BLCN film. The increase of La content in pure CO2 atmosphere increases the corrosion resistance of the film to CO2, especially for BLCN(x 鈮，

本文編號(hào)：1617968