TY - JOUR
T1 - Attainability and minimum energy of multiple-stage cascade membrane Systems
AU - Alshehri, Ali
AU - Lai, Zhiping
N1 - KAUST Repository Item: Exported on 2020-10-01
PY - 2015/8/12
Y1 - 2015/8/12
N2 - Process design and simulation of multi-stage membrane systems have been widely studied in many gas separation systems. However, general guidelines have not been developed yet for the attainability and the minimum energy consumption of a multi-stage membrane system. Such information is important for conceptual process design and thus it is the topic of this work. Using a well-mixed membrane model, it was determined that the attainability curve of multi-stage systems is defined by the pressure ratio and membrane selectivity. Using the constant recycle ratio scheme, the recycle ratio can shift the attainability behavior between single-stage and multi-stage membrane systems. When the recycle ratio is zero, all of the multi-stage membrane processes will decay to a single-stage membrane process. When the recycle ratio approaches infinity, the required selectivity and pressure ratio reach their absolute minimum values, which have a simple relationship with that of a single-stage membrane process, as follows: View the MathML sourceSn=S1, View the MathML sourceγn=γ1, where n is the number of stages. The minimum energy consumption of a multi-stage membrane process is primarily determined by the membrane selectivity and recycle ratio. A low recycle ratio can significantly reduce the required membrane selectivity without substantial energy penalty. The energy envelope curve can provide a guideline from an energy perspective to determine the minimum required membrane selectivity in membrane process designs to compete with conventional separation processes, such as distillation.
AB - Process design and simulation of multi-stage membrane systems have been widely studied in many gas separation systems. However, general guidelines have not been developed yet for the attainability and the minimum energy consumption of a multi-stage membrane system. Such information is important for conceptual process design and thus it is the topic of this work. Using a well-mixed membrane model, it was determined that the attainability curve of multi-stage systems is defined by the pressure ratio and membrane selectivity. Using the constant recycle ratio scheme, the recycle ratio can shift the attainability behavior between single-stage and multi-stage membrane systems. When the recycle ratio is zero, all of the multi-stage membrane processes will decay to a single-stage membrane process. When the recycle ratio approaches infinity, the required selectivity and pressure ratio reach their absolute minimum values, which have a simple relationship with that of a single-stage membrane process, as follows: View the MathML sourceSn=S1, View the MathML sourceγn=γ1, where n is the number of stages. The minimum energy consumption of a multi-stage membrane process is primarily determined by the membrane selectivity and recycle ratio. A low recycle ratio can significantly reduce the required membrane selectivity without substantial energy penalty. The energy envelope curve can provide a guideline from an energy perspective to determine the minimum required membrane selectivity in membrane process designs to compete with conventional separation processes, such as distillation.
UR - http://hdl.handle.net/10754/567055
UR - http://linkinghub.elsevier.com/retrieve/pii/S0376738815301198
UR - http://www.scopus.com/inward/record.url?scp=84951920234&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2015.08.020
DO - 10.1016/j.memsci.2015.08.020
M3 - Article
VL - 495
SP - 284
EP - 293
JO - Journal of Membrane Science
JF - Journal of Membrane Science
SN - 0376-7388
ER -