石墨烯為載體的銅基催化劑應(yīng)用于二氧化碳加氫合成甲醇反應(yīng)
發(fā)布時(shí)間：2018-10-09 13:52
【摘要】：二氧化碳加氫合成甲醇反應(yīng)是最具潛力的二氧化碳利用研究方向,其中該反應(yīng)所用的銅基催化劑的低活性、低甲醇選擇性和穩(wěn)定性差是影響工業(yè)化應(yīng)用的關(guān)鍵問題。本文采用石墨烯為載體,利用石墨烯載體的大比表面積和高H2和C02吸附性能,制備石墨烯為載體的銅基催化劑,從而提高催化劑的活性、選擇性和穩(wěn)定性。研究結(jié)果對提高二氧化碳加氫合成甲醇反應(yīng)催化劑的性能和未來工業(yè)化應(yīng)用具有重要的指導(dǎo)意義。本文首先建立二氧化碳加氫合成甲醇反應(yīng)過程的熱力學(xué)模型,通過Matlab模擬計(jì)算了不同溫度、壓力、H2/C02比對二氧化碳轉(zhuǎn)化率和甲醇選擇性的影響。計(jì)算結(jié)果顯示,低溫高壓有利于生成目標(biāo)產(chǎn)物甲醇。將計(jì)算值與已有實(shí)驗(yàn)值進(jìn)行比較,在相同實(shí)驗(yàn)條件下,二氧化碳轉(zhuǎn)化率仍有10%的提高空間,證明目前該反應(yīng)的限制不在熱力學(xué)而在動(dòng)力學(xué),故催化劑的開發(fā)是研究的重點(diǎn)。其次,采用共沉淀法制備CuO-ZnO-ZrO2-Al2O3/rGO (CZZA/rGO)催化劑和CuO-ZnO-ZrO2-Al2O3 (CZZA)催化劑,用于二氧化碳加氫合成甲醇反應(yīng)。采用BET、XRD、SEM、H2-TPR、H2-TPD及CO2-TPD等進(jìn)行表征,并在固定床反應(yīng)器上對其進(jìn)行催化活性評價(jià)。通過研究反應(yīng)溫度、反應(yīng)壓力和空速對二氧化碳加氫合成甲醇反應(yīng)催化劑催化性能的影響,確定本實(shí)驗(yàn)最佳反應(yīng)條件為513 K,2 MPa和6075 h-1。與此同時(shí),對比了不同催化劑CZZA/rGO和CZZA的結(jié)構(gòu)特性、還原性能、吸附性能及催化性能。結(jié)果表明：CZZA/rGO催化劑擁有大的比表面積125.56 m2·g-1,較強(qiáng)的還原性以及較好的H2和CO2吸附性能。與CZZA催化劑相比,在相同反應(yīng)條件下,隨著rGO載體的加入,CZZA/rGO催化劑的二氧化碳轉(zhuǎn)化率和甲醇收率分別增加了11.7%和18.1%,且與二氧化碳轉(zhuǎn)化率熱力學(xué)計(jì)算值相差8%。與此同時(shí),CZZA/rGO催化劑的甲醇TOF值為0.0687 s-1,遠(yuǎn)遠(yuǎn)大于CZZA催化劑的甲醇TOF值0.0083 s-1,證明CZZA/rGO催化劑的活性有很大提高。再次,采用尿素水解法制備CuO-ZnO/rGO(CZ/rGO)和CuO-ZnO/Al2O3(CZA)催化劑,改變催化劑制備條件,得到的催化劑結(jié)合BET、XRD、SEM、H2-TPR、 H2-TPD和CO2-TPD等表征手段,采用固定床反應(yīng)器在優(yōu)選反應(yīng)條件下評價(jià)催化劑性能。考察了不同水解溫度、活性組分含量及不同載體對催化劑催化性能的影響。結(jié)果表明,相比于Al2O3載體,rGO為載體的催化劑擁有更高的還原性能及H2和CO2吸附性能,且隨著活性組分含量減小,即載體量增加,H2和CO2吸附量增加,催化劑的活性組分能更多的保持在Cu0和Cu+價(jià)態(tài),提高了催化劑的還原性能。尿素水解法制備的25%CZ/75%rGO催化劑擁有最高的二氧化碳轉(zhuǎn)化率8.4%和甲醇收率7.28%,且25%CZ/75%rGO催化劑的甲醇TOF值最高達(dá)到0.0248 s-1,而CZA催化劑的甲醇TOF值僅為0.0029 s-1,證明rGO為載體的催化劑活性高。最后研究考察了催化劑的吸附性能與還原性能及催化性能的關(guān)系。研究發(fā)現(xiàn),低反應(yīng)溫度下H2和CO2吸附性能影響二氧化碳轉(zhuǎn)化率,而催化劑的總H2吸附性能影響催化劑的甲醇選擇性。以rGO為載體的催化劑擁有很強(qiáng)的H2吸附能力,其中,25%CZ/75%rG0催化劑和50%CZ/50%rGO催化劑的H2吸附量是CZA催化劑的10倍,高的H2吸附量為催化劑提供還原氛圍,使高含量載體rGO的催化劑擁有Cu0或Cu+活性中心,更有利于加氫反應(yīng)的進(jìn)行,從而提高催化劑的甲醇選擇性,甲醇選擇性在90%左右。故催化劑的H2和CO2吸附性能影響催化劑的還原性能和催化性能。
[Abstract]:The carbon dioxide hydrosynthesis methanol reaction is the most potential carbon dioxide utilization research direction, in which the low activity, low methanol selectivity and poor stability of the copper-based catalyst used in the reaction are the key problems affecting the industrialization application. In this paper, graphene is used as a carrier to prepare a copper-based catalyst with graphene as a carrier by utilizing the large specific surface area and high H2 and C02 adsorption properties of the graphene carrier, thereby improving the activity, selectivity and stability of the catalyst. The results are of great guiding significance to improve the performance and future industrial application of methanol synthesis catalyst. In this paper, the thermodynamic model of carbon dioxide hydrosynthesis methanol synthesis process was established, and the effect of different temperature, pressure, H2/ C02 ratio on the conversion of carbon dioxide and methanol selectivity was simulated by Matlab. The results show that low temperature high pressure is beneficial to the generation of target product methanol. Comparing the calculated value with the existing experimental value, under the same experimental conditions, the carbon dioxide conversion rate still has 10% improvement space, which proves that the current limit of the reaction is not in the thermodynamics, so the development of the catalyst is the focus of the research. CuO-ZnO-ZrO2-Al2O3/ rGO (CZZA/ rGO) catalyst and CuO-ZnO-ZrO2-Al2O3 (CZZA) catalyst were prepared by co-precipitation method. BET, XRD, SEM, H2-TPR, H2-TPD and CO2-TPD were used to characterize the catalytic activity. By studying the effect of reaction temperature, reaction pressure and space velocity on the catalytic performance of methanol synthesis catalyst, the optimum reaction conditions were 513K, 2MPa and 6075h-1. At the same time, the structural characteristics, reducibility, adsorption performance and catalytic performance of different catalysts CZZA/ rGO and CZZA were compared. The results show that the CZZA/ rGO catalyst has a large specific surface area of 125. 56 m2 路 g-1, stronger reducibility and better H2 and CO2 adsorption properties. Compared with CZZA catalyst, under the same reaction conditions, with the addition of rGO carrier, the conversion of carbon dioxide and methanol yield of CZZA/ rGO catalyst increased by 11. 7% and 18. 1%, respectively, and the thermodynamic calculation value of carbon dioxide conversion was 8%. At the same time, the methanol TOF value of CZZA/ rGO catalyst is 0. 0687 s-1, which is much larger than that of CZZA catalyst, and the methanol TOF value is 0. 0083 s-1. It is proved that the activity of CZZA/ rGO catalyst is greatly improved. CuO-ZnO/ rGO (CZ/ rGO) and CuO-ZnO/ Al2O3 (CZA) catalysts were prepared by urea hydrolysis, and the catalyst preparation conditions were changed. The catalysts obtained were characterized by BET, XRD, SEM, H2-TPR, H2-TPD and CO2-TPD. The effects of different hydrolysis temperature, content of active components and different carrier on the catalytic performance of catalyst were investigated. The results show that the catalyst with rGO as carrier has higher reducing energy and H2 and CO2 adsorption properties compared with Al2O3 carrier, and as the content of active component decreases, that is, the amount of carrier increases, the adsorption amount of H2 and CO2 increases, the active component of catalyst can be kept at Cu0 and Cu + valence state more, and the reducing energy of the catalyst is improved. The 25% CZ/ 75% rGO catalyst prepared by the urea hydrolysis method has the highest carbon dioxide conversion rate of 8. 4% and the methanol yield of 7.28%, and the methanol TOF value of the 25% CZ/ 75% rGO catalyst is up to 0.0248s-1, while the methanol TOF value of the CZA catalyst is only 0. 0029s-1, and the catalyst activity of the rGO as the carrier is high. The relationship between adsorption performance and reducibility and catalytic performance of catalyst was investigated. It was found that the adsorption properties of H2 and CO2 at low reaction temperature affect the conversion of carbon dioxide, and the total H2 adsorption performance of the catalyst affects the methanol selectivity of the catalyst. the catalyst with rGO as carrier has strong H2 adsorption capacity, wherein the H2 adsorption amount of 25% CZ/ 75% rG0 catalyst and 50% CZ/ 50% rGO catalyst is 10 times of CZA catalyst, the high H2 adsorption amount provides a reducing atmosphere for the catalyst, and the catalyst with high content carrier rGO has Cu0 or Cu + active center, more favorable hydrogenation reaction is carried out, so that the methanol selectivity of the catalyst is improved, and the selectivity of methanol is about 90 percent. The H2 and CO2 adsorption properties of the catalyst affect the reducibility and catalytic performance of the catalyst.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TQ223.121;O643.36
本文編號：2259573
[Abstract]:The carbon dioxide hydrosynthesis methanol reaction is the most potential carbon dioxide utilization research direction, in which the low activity, low methanol selectivity and poor stability of the copper-based catalyst used in the reaction are the key problems affecting the industrialization application. In this paper, graphene is used as a carrier to prepare a copper-based catalyst with graphene as a carrier by utilizing the large specific surface area and high H2 and C02 adsorption properties of the graphene carrier, thereby improving the activity, selectivity and stability of the catalyst. The results are of great guiding significance to improve the performance and future industrial application of methanol synthesis catalyst. In this paper, the thermodynamic model of carbon dioxide hydrosynthesis methanol synthesis process was established, and the effect of different temperature, pressure, H2/ C02 ratio on the conversion of carbon dioxide and methanol selectivity was simulated by Matlab. The results show that low temperature high pressure is beneficial to the generation of target product methanol. Comparing the calculated value with the existing experimental value, under the same experimental conditions, the carbon dioxide conversion rate still has 10% improvement space, which proves that the current limit of the reaction is not in the thermodynamics, so the development of the catalyst is the focus of the research. CuO-ZnO-ZrO2-Al2O3/ rGO (CZZA/ rGO) catalyst and CuO-ZnO-ZrO2-Al2O3 (CZZA) catalyst were prepared by co-precipitation method. BET, XRD, SEM, H2-TPR, H2-TPD and CO2-TPD were used to characterize the catalytic activity. By studying the effect of reaction temperature, reaction pressure and space velocity on the catalytic performance of methanol synthesis catalyst, the optimum reaction conditions were 513K, 2MPa and 6075h-1. At the same time, the structural characteristics, reducibility, adsorption performance and catalytic performance of different catalysts CZZA/ rGO and CZZA were compared. The results show that the CZZA/ rGO catalyst has a large specific surface area of 125. 56 m2 路 g-1, stronger reducibility and better H2 and CO2 adsorption properties. Compared with CZZA catalyst, under the same reaction conditions, with the addition of rGO carrier, the conversion of carbon dioxide and methanol yield of CZZA/ rGO catalyst increased by 11. 7% and 18. 1%, respectively, and the thermodynamic calculation value of carbon dioxide conversion was 8%. At the same time, the methanol TOF value of CZZA/ rGO catalyst is 0. 0687 s-1, which is much larger than that of CZZA catalyst, and the methanol TOF value is 0. 0083 s-1. It is proved that the activity of CZZA/ rGO catalyst is greatly improved. CuO-ZnO/ rGO (CZ/ rGO) and CuO-ZnO/ Al2O3 (CZA) catalysts were prepared by urea hydrolysis, and the catalyst preparation conditions were changed. The catalysts obtained were characterized by BET, XRD, SEM, H2-TPR, H2-TPD and CO2-TPD. The effects of different hydrolysis temperature, content of active components and different carrier on the catalytic performance of catalyst were investigated. The results show that the catalyst with rGO as carrier has higher reducing energy and H2 and CO2 adsorption properties compared with Al2O3 carrier, and as the content of active component decreases, that is, the amount of carrier increases, the adsorption amount of H2 and CO2 increases, the active component of catalyst can be kept at Cu0 and Cu + valence state more, and the reducing energy of the catalyst is improved. The 25% CZ/ 75% rGO catalyst prepared by the urea hydrolysis method has the highest carbon dioxide conversion rate of 8. 4% and the methanol yield of 7.28%, and the methanol TOF value of the 25% CZ/ 75% rGO catalyst is up to 0.0248s-1, while the methanol TOF value of the CZA catalyst is only 0. 0029s-1, and the catalyst activity of the rGO as the carrier is high. The relationship between adsorption performance and reducibility and catalytic performance of catalyst was investigated. It was found that the adsorption properties of H2 and CO2 at low reaction temperature affect the conversion of carbon dioxide, and the total H2 adsorption performance of the catalyst affects the methanol selectivity of the catalyst. the catalyst with rGO as carrier has strong H2 adsorption capacity, wherein the H2 adsorption amount of 25% CZ/ 75% rG0 catalyst and 50% CZ/ 50% rGO catalyst is 10 times of CZA catalyst, the high H2 adsorption amount provides a reducing atmosphere for the catalyst, and the catalyst with high content carrier rGO has Cu0 or Cu + active center, more favorable hydrogenation reaction is carried out, so that the methanol selectivity of the catalyst is improved, and the selectivity of methanol is about 90 percent. The H2 and CO2 adsorption properties of the catalyst affect the reducibility and catalytic performance of the catalyst.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TQ223.121;O643.36
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 陳俊軍;高文桂;王華;納薇;;CaO對Cu-ZnO-ZrO_2催化CO_2加H_2合成甲醇性能影響[J];燃料化學(xué)學(xué)報(bào);2016年04期
2 劉書群;王龍龍;劉理華;;二氧化碳捕集技術(shù)研究進(jìn)展[J];廣州化工;2014年02期
3 孔秀琴;唐興江;許珊;王曉來;;溶膠-凝膠自燃燒法制備的CuO-ZnO/Al_2O_3及催化二氧化碳加氫制甲醇的性能研究[J];分子催化;2013年02期
4 劉文艷;王華;高文桂;張明宇;張逢杰;;不同助劑對合成甲醇工業(yè)催化劑二氧化碳加氫性能的影響[J];材料導(dǎo)報(bào);2012年06期
5 錢伯章;;甲醇生產(chǎn)技術(shù)進(jìn)展[J];精細(xì)化工原料及中間體;2012年03期
6 郭曉明;毛東森;盧冠忠;王嵩;;CuO-ZnO-ZrO_2的檸檬酸燃燒法制備及其催化CO_2加氫合成甲醇的性能[J];物理化學(xué)學(xué)報(bào);2012年01期
7 張魯湘;張永春;陳紹云;;助劑TiO_2對CO_2催化加氫制甲醇催化劑CuO-ZnO-Al_2O_3性能的影響[J];燃料化學(xué)學(xué)報(bào);2011年12期
8 汪煥心;;二氧化碳加氫制甲醇是一種雙贏的化工戰(zhàn)略路線[J];廣州化工;2011年21期
9 趙云鵬;賈麗華;孫德智;鄭鐘植;;CO_2加氫合成甲醇CuO-ZnO-TiO_2催化劑的制備與表征[J];天然氣化工(C1化學(xué)與化工);2011年05期
10 周鋒;萬欣;傅迎慶;;氧化石墨還原法制備石墨烯及其吸附性能[J];深圳大學(xué)學(xué)報(bào)(理工版);2011年05期
，本文編號：2259573
本文鏈接：http://sikaile.net/kejilunwen/huaxue/2259573.html
最近更新
教材專著
