本文選題：DME + SR　； 參考：《天津大學(xué)》2015年碩士論文

【摘要】：目前化石燃料的大量使用給我們帶來了能源危機(jī)和各種各樣的環(huán)境問題。因此,有必要尋求一種清潔的可再生能源。氫氣作為一種新型的可再生能源越來越受到各國政府和研究者的關(guān)注。在過去的幾年里,氫燃料電池,如質(zhì)子交換膜燃料電池(PEMFCs),以其較高的能量轉(zhuǎn)化效率成為國內(nèi)外學(xué)者的研究熱點(diǎn)。然而作為一種新型氣態(tài)能源,氫氣難以被儲存、壓縮和運(yùn)輸。這限制了氫燃料電池在車輛上的廣泛應(yīng)用。故發(fā)展在線制氫技術(shù)很有必要。二甲醚水蒸氣重整(DME SR)制氫被認(rèn)為是一種非常有前途的車載制氫路線。針對二甲醚水蒸氣重整的特點(diǎn),我們分別研究了P改性的HZSM-5固體酸催化劑和Cu基尖晶石甲醇水蒸氣重整催化劑。采用浸漬法制備了不同P含量的P改性HZSM-5固體酸催化劑,詳細(xì)研究了P改性對HZSM-5酸性及二甲醚水蒸氣重整制氫活性的影響。與未改性的HZSM-5相比,P改性的HZSM-5催化劑(與CuZnAlO催化劑混合)在二甲醚水蒸氣重整過程中表現(xiàn)出更高的CO_2選擇性和更好的穩(wěn)定性。通過N_2吸附-脫附、XRD、O_2-TPO、NH_3-TPD、pyridine-IR、~(31)P MAS NMR等技術(shù)對催化劑進(jìn)行了表征。NH_3-TPD結(jié)果表明,P改性后HZSM-5催化劑的酸量和酸強(qiáng)度均發(fā)生了改變。結(jié)合~(31)P MAS NMR、NH_3-TPD及pyridine-IR結(jié)果,提出了P改性HZSM-5的可能的機(jī)理模型。通過檸檬酸輔助的溶膠-凝膠法制備了一系列銅基尖晶石催化劑(CuM_2O_4,M=Cr,Mn,Fe,Co,Al),并考察了銅基尖晶石催化劑與5%P/HZSM-5在二甲醚水蒸氣重整中的耦合作用。發(fā)現(xiàn)在所有的尖晶石樣品中,CuFe_2O_4催化劑具有最好的催化性能。XPS和XAFS結(jié)果表明,CuFe_2O_4催化劑具有最高的Cu~+/Cu比例,而Cu~+的存在有利于甲醇水蒸氣重整反應(yīng)中間物種HCOO-和COO-的形成,因此CuFe_2O_4催化劑具有更好的催化活性及CO_2選擇性。此外,還研究了CuFe_2O_4催化劑與5%P/HZSM-5不同混合比例對二甲醚水蒸氣重整反應(yīng)性能的影響,發(fā)現(xiàn)混合質(zhì)量比為1:1的催化劑在350 ℃時具有最好的催化活性。
[Abstract]:At present, the extensive use of fossil fuels has brought us energy crisis and various environmental problems. Therefore, it is necessary to seek a clean and renewable energy source. As a new type of renewable energy, hydrogen has been paid more and more attention by governments and researchers. In the past few years, hydrogen fuel cells, such as proton exchange membrane fuel cells (PEMFCs), have become a hot research area for their high energy conversion efficiency. However, as a new gaseous energy source, hydrogen is difficult to store, compress and transport. This limits the widespread use of hydrogen fuel cells in vehicles. Therefore, the development of online hydrogen production technology is very necessary. Dimethyl ether steam reforming (DME SR) is considered to be a promising vehicle hydrogen production route. According to the characteristics of dimethyl ether steam reforming, P-modified HZSM-5 solid acid catalyst and Cu-based spinel methanol steam reforming catalyst were studied respectively. P- modified HZSM-5 solid acid catalyst with different P content was prepared by impregnation method. The effect of P modification on HZSM-5 acid and dimethyl ether steam reforming activity was studied in detail. Compared with the unmodified HZSM-5, the modified HZSM-5 catalyst (mixed with CuZnAlO catalyst) showed higher CO-2 selectivity and better stability during the steam reforming of dimethyl ether. The results showed that the acid content and strength of the modified HZSM-5 catalyst had changed by means of N _ S _ 2 adsorption-desorption XRDO _ 2-TPOD _ 2-T _ P _ (2-TPOD) NH _ 3-TPO ~ (31) P MAS NMR technique. The results showed that the acid content and the acid strength of the modified HZSM-5 catalyst had changed. Based on the results of ~ (31) P-MAS NMR-NH3-TPD and pyridine-IR, a possible mechanism model of P-modified HZSM-5 was proposed. A series of Cu-Based spinel catalysts (CuM2O4MCrMnMnPCoCoAl) were prepared by citric acid-assisted sol-gel method. The coupling effect of Cu-based spinel catalyst and 5P- / HZSM-5 in the steam reforming of dimethyl ether was investigated. The results of XPS and XAFS showed that the CuFe2O4 catalyst had the highest Cu- / Cu ratio, and the presence of Cu- was beneficial to the formation of the intermediate species HCOO- and COO- in the steam reforming reaction of methanol, and the results of XPS and XAFS showed that the CuFe2O4 catalyst had the highest Cu / Cu ratio. Therefore, CuFe2O4 catalyst has better catalytic activity and COK2 selectivity. In addition, the effects of different mixing ratios of CuFe2O4 catalyst and 5P- / HZSM-5 on the performance of dimethyl ether steam reforming were studied. It was found that the catalyst with a mixture mass ratio of 1:1 had the best catalytic activity at 350 鈩，

本文編號：2052839