Hollow fiber membrane hydrogen recovery

Two types of membranes are used in hydrogen recovery service the spiral wound membrane and the hollow fiber membrane. The spiral wound membrane is made from flat sheets of polymer. It is illustrated in Figure 6 [9]. Hollow fiber membranes, such as those manufactured by UOP (UOP POLYSEP ) and Air Products and Chemicals (PRISM ), are illustrated in Figure 7 [lOJ. 

S. P. Kaldis, G. C. Kapantaidakis, G. P. Sakellaropoulos, Simulation of multicomponent gas separation in hollow fiber membrane by orthogonal collocation - hydrogen recovery from refinery gases, J. Membr. Sci., 173, 61-71 (2000). 

During the 1970s, considerable research and developmental work was devoted to membranes. Many potential applications were identified, but commercialization was slow. In 1977, Monsanto demonstrated its first full scale membrane separator at Texas City, Texas, in a hydrogen/carbon monoxide ratio adjustment application (Burmaster and Carter, 1983). In 1979, Monsanto commercialized its hollow fiber membrane module as the Prism separator. From 1979 to 1982 Prism separators were evaluated in several refinery hydrogen purification applications (Bollinger et al., 1982). The success of these pilot tests established the commercial viability of gas separation with membranes. The first large scale commercial CO2 membrane separation project was the installation of two membrane separation facilities at the Sacroc tertiary oil recovery project in West Texas in 1983. Up to 80 MMscfd of gas has been processed in these facilities (Parro, 1984). 

The first widespread commercial application of membrane separations is to use hollow-fiber membrane separators for hydrogen recovery from processes, ammonia plants and petrochemical purge streams, and H2/CO ratio adjustment in synthesis gas (Gardner et al., 1977 Bollinger et al., 1984 Koros and Mahajan, 2000). The reported ideal hydrogen selectivities with respect to different gases, such as CO2, CO, N2, and CH4, appear to be reasonable, ranging from 170 for H2/CH4 to 6.75 for H2/CO2. The operation of these permeators, however, is restricted to low temperatures because of the polymeric material used for the synthesis of hollow fibers. 

Gas permeation systems typically use hollow-fiber or spiral-wound membranes, although hollow-fiber systems are more common tBaker. 2004k Cellulose acetate membranes are used for carbon dioxide recovery, polysulfone coated with silicone rubber is used for hydrogen purification, and conposite membranes are used for air separation. The feed gas is forced into the membrane module under pressure. Retentate, which does not go through the membrane, will become concentrated in the less permeable gas. Retentate exits at a pressure that will be close to the input pressure. The more permeable species will be concentrated in permeate. Permeate, which has passed through the membrane, exits at low pressure. The operating cost for a gas permeator is the cost of conpression of the feed gas and the irreversible pressure difference that occurs for the gas that permeates the membrane. A typical hollow-fiber unit will contain 5000 m membrane area per m at a cost of approximately 200/m. ... 

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