Membranes Prism

Figure 8.21 Simplified flow schematic of the PRISM membrane system to recover hydrogen from an ammonia reactor purge stream. A two-step membrane system is used to reduce permeate compression costs...

Figure 8.22 Photograph of an Air Products and Chemicals, Inc. PRISM membrane system installed at an ammonia plant. The modules are mounted vertically...

Power supply, 9 from a not gas stream, 12 generation with steam, 11 Pressure control, 42,44,51,52,59,60 Pressure drop cyclone separators, 617 gas-solid flow, 119-120 granular beds, 117 heat exchanger example, 193, 194 heat exchangers, 188 non-Newtonian flow, 106-109 wire mesh pads, 616 Pressure drop, piplines, 92 chart method, 96 two-phase flow, 116 typical values, 95 Ptaskie vessel code, ASME, 625 Prilling, 361,362 equipment size, 367 flowsketch, 366 operating, data. 367 products of, 367 size distribution, 362 Prism membrane separation process, 633 643... 

Polymeric membranes, such as Air Product s PRISM membrane, have not seen use in fuel cell applications, being relegated to large-scale petrochemical, refinery, and... 

Because it is difficult to make a selective skin layer perfectly defect-free, a method was proposed by Henis and Tripodi to seal defective pores. Their method was applied to asymmetric PS membranes, which led to the production of commercial prism membranes. 

Membranes for vapor removal from air have a structure similar to the prism membrane, but they are prepared on a different principle.Aromatic PEI is used to produce a porous substrate membrane by the dry-wet phase inversion method. This polymer was chosen over PS/PES because of the higher durability of PEI to organic vapors. Unlike an asymmetric PS substrate for the prism membrane, the top layer of asymmetric PEI membrane has a large number of pores, the size of which is equivalent to those of UF membranes. When a layer of silicone rubber is coated on the top layer of the porous substrate membrane, the silicone rubber layer will govern the selectivity and the porous support will provide only mechanical strength to the composite membrane. Because the permeabilities of water and organic vapors through the silicone... 

Fig. 5 Cross-sectional view of prism membrane. 1 silicone rubber layer 2 skin layer of polysulfone 3 pores filled with silicone rubber 4 pores in the porous substrate membrane. (From Ref ()...

Monsanto s Prism permeators for gas separation also employ composite membranes. Polyamide coatings are not used for the composite membrane in the Prism module. The Prism membrane consists of a coating of silicone rubber applied from an organic solvent on a porous polysulfone substrate. The Prism membrane is another good example of a composite membrane where Structure Level IV is used to obtain good membrane properties (22). 

Membrane separation is a relatively new technology for separating gases. The PRISM membrane for hydrogen recovery was introduced by Monsanto in 1979. Others have since introduced various polymeric membranes for this application. 

Kulkami et al. (3) have reported an estimate of (Pc02 eff eff Monsanto s Prism membranes. Their value is... 

In 1980, Permea, with its hydrogen-separating Prism membrane, launched the first large industrial application of GS membranes. Since then, membrane-based operations, substituting or to be integrated with the traditional ones, have had a rapid growth, with many companies, such as Cynara-NATCO, UOP Separex, GMS, Generon, Praxair, Air Products, and Ube, involved in this field. ... 

Membranes for vapor removal from air have a structure similar to the Prism membrane, but they are prepared on a different principle [22]. Aromatic poly(etherimide) is used to produce a porous substrate membrane by the dry-wet phase inversion method. This polymer was chosen over polysulfone/poly(ether sul-... 

Currently, PRISM membranes provide an attractive alternative to traditional glycol dehydration systems (Figure 14.8) based on simple process designs, lower costs, and the other benefits listed below. These benefits become even more pronounced as the industry produces natural gas from very remote locations [55]. An offshore membrane system for Shell Nigeria was designed to dry 600000NmVh of natural gas from an inlet dew-point of 41 °C to an outlet dew-point of 0°C at 38 bar. It was designed and built by Petreco, an Air Products PRISM Membranes licensed partner. Other plants were installed in Italy and Holland. 

Advanced Prism membrane systems for cost effective gas separations, http //www. airproducts.eom/NR/rdonfyres/81FB384C-3DB5-4390-AED0-C2DB4EEDDB18/0/ PrismPGS.pdf. 

C. Aitken, K. Jones and A. Tag, PRISM Membrane Systems for Cost Efficient Natural Gas Dehydration, GPA Technical Meeting, 1998. 

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