Simulation of Hydrogen Production from Dehydrogenation of Ethanol in a Palladium Membrane Reactor

鈀膜反應器進行乙醇脫氫反應之產氫模擬

張光毅(Kuang-Yi Chang) ； 林文雄(Wen-Hsiung Lin) ； 張新褔(Hsin-Fu Chang)

《Journal of the Chinese Institute of Chemical Engineers》 33卷3期 (2002/05) Pp. 225-232

https://doi.org/10.6967/JCICE.200205.0225

摘要

本研究中，我們利用Runge-Kutta數值方法模擬乙醇脫氫反應在鈀膜反應器之產氫情形。此反應系統為析鍍鈀膜於有孔隙之不銹鋼管為內管之套管，反應端(shell side)置入適量且對乙醇脫氫反應具較佳活性之觸媒，其乙醇脫氫反應之行為依據Franckaerts和Froment (1964)的經驗速率式。在數值模擬中假設流體為柱狀流(plug flow)，省略軸向之熱及質量擴散(dispersion)傳遞，也省略徑向溫度梯度及濃度梯度的效應。模擬結果得知：薄膜反應器結合反應及分離於單一系統中，不僅增進反應轉化率且促進反應器之效率，當乙醇流率為2.37×10-6 mol/s，排除氣體(purge gas)流率達10-3 mol/s時，其轉化率可達100%，遠超過其平衡轉化率之81.7%。施以分離端(separation side)高流率排除氣體(purge gas)或以真空抽氣之適當操作條件，將可達到100%之氫氣回收。

並列摘要

In this study, we have employed a Runge-Kutta numerical method to simulate the hydrogen production from the dehydrogenation of ethanol in a palladium membrane reactor. The reacting system consists of a double-tube reactor with a palladium membrane coated on the inner porous stainless steel tube. The shell side is loaded an appropriate amount of active catalyst over which the dehydrogenation of ethanol occurs. An empirical rate law from Franckaerts and Froment (1964) is used to describe the ethanol dehydrogenation behavior. One-dimensional plug flow, negligible axial dispersion of heat and mass transfer, and negligible radial gradients of temperature and concentration are assumed before conducting the numerical simulation. The simulation results show that the membrane reactor, which combines reaction and separation in a single unit, not only increases the reaction conversion, but also improves the efficiency of the reactor. When the ethanol feed is 2.37×10-6 mole/s and with a purge gas flow rate of 10-3 mole/s in the permeation side, the conversion will achieve 100% which exceed the equilibrium value of 81.7%. With proper operating conditions, 100% recovery of hydrogen can be achieved either by using a high flow rate of purge gas in the separation side or by reducing the pressure of separation side to nearly vacuum.

並列關鍵字

Palladium membrane reactor ； Ethanol dehydrogenation ； Runge-Kutta simulation