Bifurcation and its implications for a novel autothermal circulating fluidized bed membrane reformer for the efficient pure hydrogen production
Bifurcation and its implications for a novel autothermal circulating fluidized bed membrane reformer for the efficient pure hydrogen production
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DOI：
10.1016/j.ces.2005.02.062
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发表时间：
2005-08
影响因子：
4.7
通讯作者：
Zhongxi Chen;S. Elnashaie
中科院分区：
文献类型：
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作者：
Zhongxi Chen;S. Elnashaie
本研究为重烃水蒸气重整制氢新型自热循环床膜重整装置的静态分叉行为(SBB)实验研究奠定了基础。通过两种重整装置的结构，探讨了各种设计和操作参数对重整装置性能的重要影响。一是气固分离前的催化剂再生，二是气固分离后的催化剂再生。对于两种构型，都存在三个稳态(稳态的多重性、静态分叉行为)。分叉区的系统行为相当复杂，与非自热过程的简单逻辑背道而驰。对于第一种构型，在高温稳态支路上，镍催化剂上碳的生成和沉积最高，而在低温稳态支路上净氢产率最高。对于第二种构型，庚烷的转化率始终为100%。在多重区，净氢产率由高到低依次为中、上、低温稳态，而转化炉出口碳流量从高到低依次为中、中、上温稳态。高效生产燃料电池用纯氢需要对其分叉行为有基本和实际的了解。
The present investigation is a prelude to the experimental exploration of Static Bifurcation Behavior (SBB) in a novel Autothermal Circulating Fluidized Bed Membrane Reformer (ACFBMR) for pure hydrogen production by steam reforming of heavy hydrocarbons. Important impacts of a wide range of design and operating parameters on the reformer performance are explored with two reformer configurations. One is with the catalyst regeneration before the gas–solid separation and another is with the catalyst regeneration after the gas–solid separation. For both configurations there are three steady states (multiplicity of the steady states, static bifurcation behavior). The system behavior in the bifurcation region is quite complex and defies the simple logic of non-autothermal processes. For the first configuration, on the branch of upper temperature steady state the carbon formation and deposition on the nickel catalyst is highest, while the net hydrogen yield is highest on the branch of lower temperature steady state. For the second configuration, the conversion of heptane is always 100%. In the multiplicity region, the order of net hydrogen yield from high to low is the middle, upper and lower temperature steady states, while the order of reformer exit carbon flow rate from high to low is the lower, middle and upper temperature steady states. Efficient production of pure hydrogen for fuel cells requires fundamental and practical understanding of their bifurcation behaviors.