Ceramic membranes for gas processing in coal gasification

Abstract

Coal is the most abundant fossil fuel in the world and is likely to outlast gas and oil for centuries. However, with global issues like climate change at the forefront of public attention there is a trend towards the development of a carbon constrained economy. As a result, research has intensified in the last decade on modes of operating coal fired power plants with carbon capture and storage (CCS). In particular, pre-combustion options via coal gasification, especially integrated gasification combined cycle (IGCC) processes, are attracting the attention of governments, industry and the research community as an attractive alternative to conventional power generation. It is possible to build an IGCC plant with CCS with conventional technologies however; these processes are energy intensive and likely to reduce power plant efficiencies. Novel ceramic membrane technologies, in particular molecular sieving silica (MSS) and pervoskite membranes, offer the opportunity to reduce efficiency losses by separating gases at high temperatures and pressures. MSS membranes can be made preferentially selective for H 2 , enabling both enhanced production, via a water-gas shift membrane reactor, and recovery of H 2 from the syngas stream at high temperatures. They also allow CO 2 to be concentrated at high pressures, reducing the compression loads for transportation and enabling simple integration with CO 2 storage or sequestration operations. Perovskite membranes provide a viable alternative to cryogenic distillation for air separation by delivering the tonnage of oxygen required for coal gasification at a reduced cost. In this review we examine ceramic membrane technologies for high temperature gas separation and discuss the operational, mechanical, design and process considerations necessary for their successful integration into IGCC with CCS systems.

High performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer

“…Low chemical and thermal stability and plasticization at high pressures in the presence of strong adsorbing penetrants such as CO 2 are among the main disadvantages of this type of membranes. On the other hand, although inorganic membranes based on ceramics [9], carbon [10], zeolite [11], oxides [12], metal organic frameworks (MOF) [13] or metals [14] present an excellent thermal and chemical stability, good erosion resistance and high gas flux and selectivity for gas separation, their implementation at industrial scale has been hampered due to the low mechanical resistance, modest reproducibility, scale-up problems and the high fabrication cost of this type of membranes [13,15].…”

Permeation model and experimental investigation of mixed conducting membranes

“…[1][2][3] The MIEC materials can be applied potentially in the field of oxygen separation, solid oxide fuel cells (SOFCs), [4][5][6] membrane reactors for the partial oxidation of light hydrocarbons, [7][8][9][10] oxy-fuel process for CO 2 capture, and so on. 11,12 Oxygen permeation fluxes through MIEC membranes can be well described by the Wagner equation, which assumes the bulk diffusion to be the rate determining step (r.d.s.). 13 If the dipole conductivity is marginally affected by oxygen partial pressure across membranes, the equation shows a simple dependence of oxygen flux on the operating temperature and oxygen partial pressure.…”

Study of the Transport Properties of the Mixed Ionic Electronic Conductor Ce1−xTbxO2−δ + Co (x = 0.1, 0.2) and Evaluation As Oxygen-Transport Membrane

“…The current state of technology development for ASU applies high energy consuming cryogenic distillation units while alternative oxygen separation technologies such as ion transport membranes [2] would enable thermal integration and energy savings. Furthermore, several chemical processes [3,4,5,6,7] would benefit from the development of highly-permeable and CO 2 stable ceramic membranes, since it would make possible the process intensification and the improvement of product selectivity by avoiding the direct contact of molecular oxygen and reaction products.…”