本文選題：電化學氫泵反應器 + 非均相催化加氫��； 參考：《大連理工大學》2016年碩士論文

【摘要】：近年來,生物質(zhì)作為可持續(xù)能源受到廣泛關注,越來越多的研究集中于其提質(zhì)流程中的加氫過程。而電化學氫泵反應器具有在陰極催化劑表面生成原位吸附氫的特殊結構,可使加氫過程在常溫常壓下進行,避免了傳統(tǒng)加氫反應器中高溫高壓操作帶來的一系列設備和操作復雜性。但是目前電化學氫泵加氫反應器的氫源為純氫或水,純氫高昂的價格和水電解的巨大電能消耗,阻礙電化學氫泵加氫反應器的進一步發(fā)展。本文提出脫氫與加氫耦合的電化學氫泵雙反應器解決上述難題,即利用電化學氫泵反應器中質(zhì)子交換膜的分隔作用,使脫氫反應與加氫反應同時在陽、陰極進行且互不影響,陽極有機物脫氫產(chǎn)生的H+通過質(zhì)子交換膜傳遞至陰極催化劑表面,直接供給陰極加氫。與水做氫源相比,有機物具有較低的電化學窗口,可降低脫氫電勢和供氫能源成本；脫氫與加氫在同一反應器中完成,提升了反應器的整體效率、降低設備成本�；陔娀瘜W氫泵雙反應器的設想,本文嘗試了異丙醇-苯酚雙反應器。陽極異丙醇在常用陽極催化劑Pt催化下脫氫生成氫氣和丙酮,通過改進實驗條件使脫氫電勢穩(wěn)定在0.85 V。并考察了生物質(zhì)模型化合物苯酚在電化學氫泵反應器的加氫反應,環(huán)已醇選擇性可達95.4%,加氫速率達到17.0 nmol cm-2 s-1。在此基礎上,成功運行Pt-Nafion-Pt異丙醇-苯酚雙反應器,陰極苯酚加氫反應速率9.7 nmol cm-2 s-1,陽極電勢約為0.9 V。進而,本文針對上述反應器存在陽極過電勢高,環(huán)已酮產(chǎn)率低的問題進一步改進。陽極通過使用PtRu催化劑,增大催化劑擔載量,脈沖電流以及操作條件優(yōu)化,將異丙醇脫氫電勢進一步降低至0.2 V,并可長時間穩(wěn)定運行,僅為同條件下水脫氫電勢的1-10。同時以苯酚加氫得到更多環(huán)已酮為目標,改用Pd催化劑并進行進一步優(yōu)化,優(yōu)選擴散層、催化劑擔載量、操作條件等,其在80℃時,催化加氫生成環(huán)已酮速率達11.0 nmolcm-2 s-1,高于文獻報道的Pd-C催化的三相反應速率。并成功運行PtRu-Nafion-Pt/Pd異丙醇-苯酚雙反應器,其中PtRu-Nafion-Pt反應器陰極加氫速率達到19.3 nmol cm-2 s-1,陽極電勢可穩(wěn)定在0.2 V,證明雙反應器的可行性和精確控制反應的優(yōu)勢。針對前文陰極苯酚滲透導致脫氫電勢升高問題,探究了另一種生物質(zhì)模型化合物乙酰丙酸在電化學氫泵陰極的加氫反應,實驗表明PtRu催化乙酰丙酸加氫的活性高于Pt。乙二醇作為陽極反應物,其相比異丙醇,可提供較高的電流密度,80℃可達到130 mAcm-2。并進一步成功運行PtRu-Nafion-Pt/PtRu乙二醇-乙酰丙酸雙反應器,其陰極加氫反應速率均高于單獨氫泵反應器的加氫速率,整個過程中電壓持續(xù)穩(wěn)定在0.5 V。
[Abstract]:In recent years, biomass as a sustainable energy has received extensive attention, and more and more research has focused on the hydrogenation process in the process of improving the quality of biomass.The electrochemical hydrogen pump reactor has a special structure of in-situ hydrogen adsorption on the surface of the cathode catalyst, which can make the hydrogenation process take place at room temperature and atmospheric pressure.A series of equipment and operation complexity caused by high temperature and high pressure operation in traditional hydrogenation reactor are avoided.But at present the hydrogen source of electrochemical hydrogen pump hydrogenation reactor is pure hydrogen or water. The high price of pure hydrogen and the huge electric energy consumption of water electrolysis hinder the further development of electrochemical hydrogen pump hydrogenation reactor.In this paper, an electrochemical hydrogen pump dual reactor coupled with dehydrogenation and hydrogenation is proposed to solve the above problem, that is, by using the separation of proton exchange membrane in the electrochemical hydrogen pump reactor, the dehydrogenation reaction and the hydrogenation reaction are carried out simultaneously in the positive, cathode and without influence on each other.The H produced by the dehydrogenation of anodic organic compounds is transferred to the surface of the cathode catalyst through the proton exchange membrane and directly supplied to the cathode hydrogenation.Compared with water as hydrogen source, organic compounds have lower electrochemical window, which can reduce the potential of dehydrogenation and the cost of hydrogen supply energy, and the dehydrogenation and hydrogenation are completed in the same reactor, which improves the overall efficiency of the reactor and reduces the equipment cost.Based on the assumption of electrochemical hydrogen pump dual reactor, this paper tries to use isopropanol-phenol dual reactor.Anodic isopropanol was dehydrogenated to produce hydrogen and acetone under the catalysis of common anode catalyst Pt. The potential of dehydrogenation was stabilized at 0.85 V by improving the experimental conditions.The hydrogenation of phenol, a biomass model compound, in an electrochemical hydrogen pump reactor was investigated. The selectivity of cyclohexanol was 95.4 and the hydrogenation rate was 17.0 nmol cm-2 s-1.On this basis, the Pt-Nafion-Pt isopropanol-phenol dual reactor was successfully operated. The reaction rate of cathodic phenol hydrogenation was 9.7 nmol cm-2 s-1, and the anode potential was about 0.9 V.Furthermore, the problems of high anode overpotential and low cyclohexanone yield in the above reactors are further improved.By using PtRu catalyst, the catalyst load, pulse current and operation conditions were optimized to further reduce the dehydrogenation potential of isopropanol to 0.2V and to run stably for a long time, which was only 1-10 of the dehydrogenation potential in water under the same conditions.At the same time, more cyclohexanone was obtained by hydrogenation of phenol, PD catalyst was used and optimized, diffusion layer was selected, catalyst loading capacity, operating conditions, etc., at 80 鈩，

本文編號：1734633