ABSTRACT
Nowadays, the ever more pressing necessity for sustainability is pushing interested parties to substitute traditional industrial growth with sustainable growth. In the recent Research Agenda published as part of the Delft Skyline Debates,1 the development of the industrial system in the year 2050 has been well dened. In many strategic sectors such as water, energy, food, and health, the necessary transformations will take place consistently with process intensication principles. These are based on innovative equipment, design, and process development methods that are expected to bring substantial improvements in petrochemical, chemical, and any other
manufacturing and processing procedures, such as decreasing production costs, equipment size, energy consumption, and waste generation and improving remote control, information uxes, and process exibility.2 An important contribution to the attainment of sustainable industrial development can be made by green process engineering. The latter is based on the principles of process intensication strategy, which can lead to the development and the redesigning of more compact and efcient new processes that allow better exploitation of the raw material, lower energy consumption, and a reduced plant volume. A deep understanding of this principle places membrane technology and membrane engineering in
5.1 Introduction ....................................................................................................................................................................... 77 5.2 Membrane Gas Separation................................................................................................................................................. 78
5.2.1 Hydrogen Recovery ............................................................................................................................................... 79 5.2.2 Natural Gas Membrane Processing ....................................................................................................................... 80 5.2.3 Enhanced Oil Recovery ......................................................................................................................................... 81 5.2.4 Vapor/Gas Separation ............................................................................................................................................ 81 5.2.5 Olen/Parafn Separation ..................................................................................................................................... 82 5.2.6 Air Separation ........................................................................................................................................................ 83
5.2.6.1 Air Drying .............................................................................................................................................. 83 5.2.7 CO2 Capture ........................................................................................................................................................... 84 5.2.8 Traditional Technologies for Separation of Gases ................................................................................................. 84
5.3 Membrane Reactors ........................................................................................................................................................... 85 5.3.1 Precombustion Capture by Means of Inorganic Membrane Reactors ................................................................... 85 5.3.2 Benzene Hydroxylation to Phenol ......................................................................................................................... 87 5.3.3 Dehydroisomerization of Butane to Isobutene ...................................................................................................... 88
5.4 PV Processes ...................................................................................................................................................................... 88 5.4.1 Gasoline Desulphurization .................................................................................................................................... 88
5.4.1.1 Other Applications of PV ........................................................................................................................ 89 5.5 Organic Solvent Nanoltration .......................................................................................................................................... 90 5.6 Membrane Systems for Water Recovery ........................................................................................................................... 91
5.6.1 Pressure-Driven Processes for the Purication of Water from Oil ....................................................................... 91 5.6.2 Membrane Bioreactors for Water Treatment ......................................................................................................... 91
5.7 Metrics and Process Intensication ................................................................................................................................... 93 5.7.1 Case Study: Hydrogen Separation in Reneries .................................................................................................... 93
5.7.1.1 Operating Flexibility ............................................................................................................................... 93 5.7.1.2 Turndown ................................................................................................................................................ 93 5.7.1.3 Reliability ................................................................................................................................................ 93 5.7.1.4 Ease of Expansion ................................................................................................................................... 93 5.7.1.5 By-Product Value .................................................................................................................................... 94
5.8 Conclusions ........................................................................................................................................................................ 96 References ................................................................................................................................................................................... 97
a crucial role for the implementation of this strategy. The growth of membrane engineering has been signicant in the last few years, and various large unit operations of process engineering have already been redesigned as a membrane unit.3 With their intrinsic characteristics of efciency and operational simplicity, high selectivity and permeability for the transport of specic components, compatibility between different membrane operations in integrated systems, low energetic requirement, good stability under operating conditions and environment compatibility, easy control and scaleup, and large operational exibility, membrane operations are an interesting answer for the rationalization of chemical productions. Membrane reactors (MRs), membrane gas separation (GS), pervaporation (PV), membrane emulsiers, membrane distillation, membrane crystallizers, membrane contactors, and membrane strippers and scrubbers, in their various congurations and functionalities, are growing in parallel to the molecular separations created with pressuredriven membrane operations. There are already interesting cases where the potentialities of these technologies have been explored. The most important is the success of pressuredriven membrane operations in water and brackish water desalination and in water reuse, where reverse osmosis (RO), nanoltration (NF), ultraltration (UF), and microltration (MF) might be considered as dominant technologies. The latest development of immersed bioreactors in the treatment of municipal wastewater is another important example.
