Gas separation process

Selective membrane diffusion processes also offer a promising approach to separating hot gases and these are discussed below in Section 2.6. 

---

Fig. 16.4. Schematic diagram of the basic membrane gas separation process.

In the present study, we fabricated hollow fiber membrane modules and performed experiments at several conditions. The energy consumption of this process is compared to those of conventional gas absorption processes and membrane gas separation processes. 

Compression If compression of either feed or permeate is required, it is highly likely that compression capital and operating costs will dominate the economics of the gas-separation process. In some applications, pressure is essentially free, such as when removing small quantities of CO2 from natural gas. The gas is often... 

Wang J (2004) Synthesis and Optimization of Low Temperature Gas Separation Processes, PhD Thesis, UMIST, UK. 

A timely chapter on the theory and applications of electrochemical gas separation processes is presented by Jack Winnick. These alternatives for the removal of dilute components from gas streams in pure form are characterized by high selectivity, simplicity, and favorable economics. 

Current C02 capture technology (first generation) is adapted from gas separation processes already in industrial use. There are several technologies and strategies to capture C02 from stationary sources pre-combustion, post-combustion and oxy-fuel (Figure 2). 

Mehra (2) [Named after the inventor] A gas separation process utilizing absorption in a solvent at moderate pressures. Developed by Advanced Extraction Technologies and applied to hydrogen recovery, nitrogen rejection, and recovery of natural gas liquids. 

It is known that fluorinated compounds dissolve considerable amounts of oxygen19 and that membranes containing ultrahydrophobic moieties show a high selectivity in gas-separation processes, e.g., in 02/N2 separation. 

In pressure-driven gas separation processes, several transport mechanisms can occur. These can be divided into gas phase transport and transport... 

Polymer membranes are the most common commercial membranes for separations [1]. They have proven to operate successfully in many gas and liquid separations. For example, polymer membrane-based gas separation processes have undergone a major evolution since the introduction of the first polymer membrane-based industrial hydrogen separation process about two decades ago. The... 

While many people have contributed to the Ideas presented In this paper, the authors wish to particularly acknowledge the work of Dr. A. M. Peiser of Mobil Research and Development Corporation In the development of new oil-gas separation processes for North See operations. S. F. King of Mobil Exploration and Producing Services Inc., also made significant contributions to this paper. 

W.J. Koros and I. Pinnau, Membrane Formation for Gas Separation Processes, in Polymeric Gas Separation Membranes, D.R. Paul and Y.P. Yampol skii (eds), CRC Press, Boca Raton, FL, pp. 209-272 (1994). 

M. Langsam, Fluorinated Polymeric Membranes for Gas Separation Processes, US Patent 4,657,564 (April, 1987) M. Langsam and C.L. Savoca, Polytrialkylgermyl-propyne Polymers and Membranes, US Patent 4,759,776 (July, 1988). 

M. Langsam, Fluorinated Polymeric Membranes for Gas Separation Processes, US Patent 4,657,564 (April, 1987). 

Concentration polarization in gas separation processes has not been widely studied, and the effect is often assumed to be small because of the high diffusion coefficients of gases. However, the volume flux of gas through the membrane is also high, so concentration polarization effects are important for several processes. 

Gas separation process Pressure-normalized flux, P/i [10 6 cm3(STP)/ cm2 s cmHg] Pressure feed/permeate (atm/atm) Volume flux at feed pressure, JVf (10-3 cm3/cm2 s) Membrane selectivity, a Enrichment, E0 Feed gas diffusion coefficient at feed pressure (10-3 cm2/s) Peclet number, JVfS/Dj(yA04) Concentration polarization modulus [Equation (4.24)]... 

Table 8.1 are measured with pure gases the selectivity obtained from the ratio of pure gas permeabilities gives the ideal membrane selectivity, an intrinsic property of the membrane material. However, practical gas separation processes are performed with gas mixtures. If the gases in a mixture do not interact strongly with the membrane material, the pure gas intrinsic selectivity and the mixed... 

Most gas separation processes require that the selective membrane layer be extremely thin to achieve economical fluxes. Typical membrane thicknesses are less than 0.5 xm and often less than 0.1 xm. Early gas separation membranes [22] were adapted from the cellulose acetate membranes produced for reverse osmosis by the Loeb-Sourirajan phase separation process. These membranes are produced by precipitation in water the water must be removed before the membranes can be used to separate gases. However, the capillary forces generated as the liquid evaporates cause collapse of the finely microporous substrate of the cellulose acetate membrane, destroying its usefulness. This problem has been overcome by a solvent exchange process in which the water is first exchanged for an alcohol, then for hexane. The surface tension forces generated as liquid hexane is evaporated are much reduced, and a dry membrane is produced. Membranes produced by this method have been widely used by Grace (now GMS, a division of Kvaemer) and Separex (now a division of UOP) to separate carbon dioxide from methane in natural gas. 

Removal of carbon dioxide is the only membrane-based natural gas separation process currently practiced on a large scale—more than 200 plants have been installed, some very large. Most were installed by Grace (now Kvaerner-GMS), Separex (UOP) and Cynara and all use cellulose acetate membranes in hollow fiber or spiral-wound module form. More recently, hollow fiber polyaramide (Medal) membranes have been introduced because of their higher selectivity. 

Polymeric membranes also have vast applications in several processes, such as desalination using reverse osmosis membranes. Filtration, in a wide sense, with polymeric membranes can be applied in gas separation processes, biochemical processing, wastewater treatment, food and beverage production, and pharmaceutical applications [59-61],... 

---