Modelling of packed bed membrane reactors for autothermal production of ultrapure hydrogen

详细信息	查看全文 | 推荐本文 |

• 作者：T.P. Tiemersma ; C.S. Patil ; M. van Sint Annaland and J.A.M. Kuipers
• 关键词：Modelling ; Membranes ; Packed bed ; Chemical reactors ; Hydrogen ; Autothermal operation
• 刊名：Chemical Engineering Science
• 出版年：2006
• 期刊代码：18_00092509
• 类别：ce
• 出版时间：March 2006
• 卷：61
• 期：5
• 页码：1602-1616
• 文件大小：1252 K

摘要

The conceptual feasibility of a packed bed membrane reactor for the autothermal reforming (ATR) of methane for the production of ultrapure hydrogen was investigated. By integrating me="mml129">method=retrieve&_udi=B6TFK-4HJRRYK-1&_mathId=mml129&_user=10&_cdi=5229&_rdoc=25&_handle=V-WA-A-W-BD-MsSAYWW-UUA-U-AAVCVVUZCA-AAVBUWAVCA-DBZDVVADA-BD-U&_acct=C000050221&_version=1&_userid=10&md5=c8e45a7a2fcd79cd25daaef39679e0f4" title="Click to view the MathML source">H₂ permselective Pd-based membranes under autothermal conditions, a high degree of process integration and intensification can be accomplished which is particularly interesting for small scale me="mml130">method=retrieve&_udi=B6TFK-4HJRRYK-1&_mathId=mml130&_user=10&_cdi=5229&_rdoc=25&_handle=V-WA-A-W-BD-MsSAYWW-UUA-U-AAVCVVUZCA-AAVBUWAVCA-DBZDVVADA-BD-U&_acct=C000050221&_version=1&_userid=10&md5=f9cb4f1b2a06b610703b372c3e0112ee" title="Click to view the MathML source">H₂ production units. A two-dimensional pseudo-homogeneous packed bed membrane reactor model was developed that solves the continuity and momentum equations and the component mass and energy balances. In adiabatic operation, autothermal operation can be achieved; however, large axial temperature excursions were seen at the reactor inlet, which are disadvantageous for membrane life and catalyst performance. Different operation modes, such as cooling the reactor wall with sweep gas or distributive feeding of me="mml131">method=retrieve&_udi=B6TFK-4HJRRYK-1&_mathId=mml131&_user=10&_cdi=5229&_rdoc=25&_handle=V-WA-A-W-BD-MsSAYWW-UUA-U-AAVCVVUZCA-AAVBUWAVCA-DBZDVVADA-BD-U&_acct=C000050221&_version=1&_userid=10&md5=8920203122320586d8cf690500a78d66" title="Click to view the MathML source">O₂ along the reactor length to moderate the temperature profile, are evaluated. The concentration polarisation because of the selective hydrogen removal along the membrane length was found to become significant with increasing membrane permeability thereby constraining the reactor design. To decrease the negative effects of mass transfer limitations to the membrane wall, a small membrane tube diameter needs to be selected. For a relatively small ratio of the membrane tube diameter to the particle diameter, the porosity profile needs to be taken into account to prevent overestimation of the me="mml132">method=retrieve&_udi=B6TFK-4HJRRYK-1&_mathId=mml132&_user=10&_cdi=5229&_rdoc=25&_handle=V-WA-A-W-BD-MsSAYWW-UUA-U-AAVCVVUZCA-AAVBUWAVCA-DBZDVVADA-BD-U&_acct=C000050221&_version=1&_userid=10&md5=3e0dfc50049fd5fe1ecc41c390e9fd25" title="Click to view the MathML source">H₂ removal rate. It is concluded that autothermal production of me="mml133">method=retrieve&_udi=B6TFK-4HJRRYK-1&_mathId=mml133&_user=10&_cdi=5229&_rdoc=25&_handle=V-WA-A-W-BD-MsSAYWW-UUA-U-AAVCVVUZCA-AAVBUWAVCA-DBZDVVADA-BD-U&_acct=C000050221&_version=1&_userid=10&md5=e4b8df90a3e3bbed6f60a516f7a10cf5" title="Click to view the MathML source">H₂ in a PBMR is feasible, provided that the membranes are positioned outside the inlet region with large temperature gradients.