Membrane-Cryogenic Post-Combustion Carbon Capture of Flue Gases from NGCC

Abstract

Membrane gas separation for carbon capture has traditionally been focused on high pressure applications, such as pre-combustion capture and natural gas sweetening. Recently a membrane-cryogenic combined process has been shown to be cost competitive for post-combustion capture from coal fired power stations. Here, the membrane-cryogenic combined process is investigated for application to post-combustion carbon capture from the flue gas of a Natural Gas Combined Cycle (NGCC) process. This process involves a three-membrane process, where the combustion air is used as the sweep gas on the second membrane stage to recycle CO 2 through the turbine. This ensures high CO 2 recovery and also increases the CO 2 partial pressure in the flue gas. The three-CO 2 -selective membrane process with liquefaction and O 2 -enrichment was found to have a cost of capture higher than the corresponding process for coal post-combustion capture. This was attributed to the large size and energy duty of the gas handling equipment, especially the feed blower, because of the high gas throughput in the system caused by significant CO 2 recycling. In addition, the economics were uncompetitive compared to a modelled solvent absorption processes for NGCC.

A Prospective Concept on the Fabrication of Blend PES/PEG/DMF/NMP Mixed Matrix Membranes with Functionalised Carbon Nanotubes for CO2/N2 Separation

“…Additionally, higher CO 2 pressure and are is achieved during capture, requiring more energy and cost [ 20 ]. This system utilises four different techniques, namely adsorption, absorption, cryogenic distillation and membranes [ 21 ]. By using these techniques, there can be flexibility in operation, as they can be retrofitted into existing plants and, therefore, revisions in the combustion cycle are not required [ 11 ].…”

Thermodynamic Simulation of Organic Rankine Cycle (ORC) for Electricity Generation from Low-Grade Waste Heat

“…Natural gas was suitably fed for those engines while the operating engine conditions were given in Table I. The combustion of natural gas engine was assumed to be perfect combustion and the composition of exhaust gas on molar basis was comprised of: CO 2 =4.97%, N 2 =74.28%, O 2 =9.73% and H 2 O = 11.02% [10]. The schematic diagram and T-s diagram of the ORC system can be illustrated as in Fig.1 and Fig.2, respectively.…”

The Potential of CO2 Capture and Storage Technology in South Africa’s Coal-Fired Thermal Power Plants

“…In the pre-combustion capture, fuel from the power plant is reacted with oxygen to generate a syngas mixture, which is carried out in the gasification step [55][56][57][58][59][60]. Carbon dioxide is then reacted with steam in the second step to produce CO 2 and H 2 before the CO 2 is finally separated using a physical or chemical absorption process [61][62][63][64][65]. The pre-combustion capture technique incurs high costs for chemical solvent regeneration.…”