Membrane processes for post-combustion carbon dioxide capture: A parametric study (original) (raw)
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International Journal of Greenhouse Gas Control, 2014
The effectiveness of membrane processes and feasibility of hybrid processes combining membrane permeation and conventional amine absorption processes were investigated for post-combustion CO 2 capture. The traditional MEA process uses a substantial amount of thermal energy at the stripper reboiler when CO 2 concentration increases. Questions are sometimes raised if the membranes can compete with amine absorption for post-combustion CO 2 capture. Although both processes have their own advantages, can a hybrid process for post-combustion CO 2 capture be yielded combining membranes and amine absorption with cost/performance advantages? Several single stage and multi-stage membrane process configurations were simulated for a target capture requirement aiming at possible application in enhanced oil recovery. It was shown that membrane processes offer the lowest energy penalty for post-combustion CO 2 capture and are likely to expand as more and more CO 2 selective membranes are developed. A comparison of energy perspective for the CO 2 capture processes studied was drawn, and it was shown that the energy requirements of the hybrid processes are less than conventional MEA processes. The total energy penalty of the hybrid processes decreases as more share of CO 2 is removed by the membranes.
International Journal of Greenhouse Gas Control, 2017
Membrane separation is considered to be the most promising alternative to chemical absorption for decarbonizing fossil fuel power generating systems. However, the implementation of a membrane system has several implications for the energy and economic performances of power plants. Indeed, membrane systems allow for the non-negligible reduction of power plant capacity, which can negatively affect its efficiency. This aspect, combined with the additional capital and operating expenses, is also responsible for an increase in the electricity generation costs. Currently, the majority of studies neglected to investigate the influence of CO 2 separation targets on costs, thus limiting their investigation to the case of geological storage or enhanced oil recovery (EOR) that mean CO 2 purity levels after compression higher than 95%. But for certain valorization aims, like CO 2 hydrogenation or solar thermochemical conversion, lower CO 2 quality standards may be sufficient; to the best of our knowledge there is currently no study allowing to know the cost of CO 2 capture in this unusual framework. The aim of this paper was to analyze the effects of CO 2 purity targets on the energy requirement for the separation and compression operations and costs of membrane systems, considering as a study case the recovery of CO 2 from flue gases of a coal-fired power plant and using a Polyactive membrane. The CO 2 separation process was first investigated by exploring several membrane system concepts. Then, by focusing on dual-stage configurations, the entire carbon capture and storage (CCS) chain was analyzed. From an energy view point, the study quantified the impact of CO 2 capture retrofit intervention on the power plant's net efficiency and the extent of CO 2 emissions reduction. Besides, the economic analysis allowed for an evaluation of the specific cost of the CO 2 capture and the mitigation cost with or without credits for EOR. Finally, an energy and economic comparison was made with the CO 2 capture based on chemical scrubbing. With a CO 2 separation cost of 20÷33 /tonne,asinglestagemembranesystemwithfeedcompressionandpermeatevacuumpumpingrepresentsthemostinterestingoptiontobeusedincombinationwithCO2recyclingtechnologiesrequiringamedium−lowCO2puritylevel(70÷80/tonne, a single stage membrane system with feed compression and permeate vacuum pumping represents the most interesting option to be used in combination with CO 2 recycling technologies requiring a medium-low CO 2 purity level (70÷80%). Simulation results also revealed that dual stage membrane systems envisaged are economically competitive compared to amine absorption processes in the case of geological storage, involving a cost of CO 2 capture of 36÷41 /tonne,asinglestagemembranesystemwithfeedcompressionandpermeatevacuumpumpingrepresentsthemostinterestingoptiontobeusedincombinationwithCO2recyclingtechnologiesrequiringamedium−lowCO2puritylevel(70÷80/tonne. Research efforts are currently focused on optimizing scrubbing technology using novel solvents (
Post-Combustion CO2 Capture from Exhaust Gas by Amines and Membranes
Applied Mechanics and Materials, 2016
There is a necessity to reduce GHG emission because climate change may have critical consequences in many places around the world. The main gas which causes climate change is CO2 which is released into atmosphere mainly by industries and vehicles. This research aims to compare two technologies for CO2 capture: chemical absorption with membranes, and to present hybrid processes using both of these. A review of the state of art for CO2 capture is used in this research. The capture by absorption with amines is the state of the art for post-combustion because it produces CO2 with higher purity and is cheaper. However, the energy and installation cost are high which does do not encourage its applicability. Membrane for CO2 capture from natural gas is promissory because of this. Thus, researchers have studied other technologies for CO2 capture to replace or add through including hybrid processes. Capture by membrane is a promising technology for this, provided that since it presents appro...
Journal of Membrane Science, 2018
Pre-combustion CO 2 capture is regarded as a promising option to mitigate the environmental pollution from coal combustion, due to its relatively low energy duty and prospects for the use of hydrogen in power generation and industrial sectors. Nowadays, research and development efforts are mainly focusing on advanced technologies to separate H 2 and CO 2 from a synthesis gas of a gasification-based power generation system. In this regard, membrane separation processes are attracting an increasing attention, due to their potential for a more costeffective and environmental friendly CO 2 capture compared to well-established solvent-based processes. A conceptual design and techno-economic analysis is presented of a pre-combustion CO 2 capture process based on H 2-selective polymeric membranes in an integrated gasification combined cycle (IGCC) power plant, including the water-gas-shift (WGS) system. The design approach is based on the selection of the most effective membrane separation process and economic optimisation of operating conditions. The capture process is based on a three-stage membrane separation system, producing a hydrogen stream feeding the power generation unit and a liquid CO 2 stream, ready for transport and geological storage. Considering a state-of-the-art polymeric membrane with a H 2 to CO 2 selectivity of 15 and H 2 permeance of 300 GPU, the IGCC efficiency penalty states at around 5% pts when the separation process is operated with a pressure on membrane feed side of 70 bar, corresponding to an estimated cost of CO 2 capture of 16.6 €/t CO 2. A sensitivity analysis of operating pressure and membrane properties revealed that the cost of CO 2 capture can be reduced to less than 15 €/t CO 2 by moderately increasing the H 2 to CO 2 selectivity and adjusting the designed process accordingly. Additionally, a decrease in the feed-side pressure slightly disfavours the economic performance of CO 2 capture for H 2 permeances greater than 300 GPU. The membrane-based capture process compared most favourably in costeffectiveness with the well-established solvent based Selexol process. Keywords: process optimisation; process economics; IGCC power plant; membrane H 2 separation; pre-combustion CO 2 capture Highlights A pre-combustion CO 2 capture system based on H 2-selective membranes is designed The pre-combustion CO 2 capture process is integrated into an IGCC power plant A process economic optimization minimizes the cost of CO 2 capture Cost of CO 2 capture reaches 16.6 €/t for a state-of-the-art H 2-selective membrane Slightly increasing the H 2 /CO 2 selectivity, cost of CO 2 capture reduces to 15 €/t
Power plant post-combustion carbon dioxide capture: An opportunity for membranes
Journal of Membrane Science, 2010
Carbon dioxide capture from power plant flue gas and subsequent sequestration is expected to play a key role in mitigating global climate change. Conventional amine technologies being considered for separating CO 2 from flue gas are costly, energy intensive, and if implemented, would result in large increases in the cost of producing electricity. Membranes offer potential as an energy-efficient, low-cost CO 2 capture option. Recently, working with the U.S. Department of Energy (DOE), we have developed membranes with CO 2 permeances of greater than 1000 gpu and a CO 2 /N 2 selectivity of 50 at 30 • C. This permeance is ten times higher than commercial CO 2 membranes and the selectivity is among the highest reported for non-facilitated transport materials. These membranes, in combination with a novel process design that uses incoming combustion air as a sweep gas to generate driving force, could meet DOE CO 2 capture cost targets. Under these conditions, improving membrane permeance is more important than increasing selectivity to further reduce the cost of CO 2 capture from flue gas. Membrane cost and reliability issues will be key to the eventual competitiveness of this technology for flue gas treatment.
Post-combustion CO2 capture with chemical absorption: A state-of-the-art review
Chemical Engineering Research and Design, 2011
Global concentration of CO 2 in the atmosphere is increasing rapidly. CO 2 emissions have an impact on global climate change. Effective CO 2 emission abatement strategies such as Carbon Capture and Storage (CCS) are required to combat this trend. There are three major approaches for CCS: Post-combustion capture, Pre-combustion capture and Oxyfuel process. Post-combustion capture offers some advantages as existing combustion technologies can still be used without radical changes on them. This makes postcombustion capture easier to implement as a retrofit option (to existing power plants) compared to the other two approaches. Therefore, post-combustion capture is probably the first technology that will be deployed. This paper aims to provide a state-of-the-art assessment of the research work carried out so far in post-combustion capture with chemical absorption. The technology will be introduced first, followed by required preparation of flue gas from power plants to use this technology. The important research programmes worldwide and the experimental studies based on pilot plants will be reviewed. This is followed by an overview of various studies based on modelling and simulation. Key issues such as energy consumption and plant flexibility will be included. Then the focus is turned to review development of different solvents and process intensification. Based on these, we try to predict challenges and potential new developments from different aspects such as new solvents, pilot plants, process heat integration (to improve efficiency), modelling and simulation, process intensification and government policy impact.
Separation and Purification …, 2009
For carbon dioxide capture and storage (CCS), similar to a large majority of industrial processes, the separation (i.e. capture) step dominates the costs of the technological chain. Based on a concept of minimal work of concentration, the evaluation of a tentative capture framework which combines an oxygen enrichment step before combustion and a CO 2 capture step from flue gas has been investigated through a simulation study. The performances of a cryogenic oxygen production process have been used for the upstream part, while a membrane separation process based on CO 2 selective materials has been investigated for CO 2 capture. The potentialities of this hybrid process from the energy requirement point of view are discussed. It is shown that the hybrid process can lead to a 35% decrease of the energy requirement (expressed in GJ per ton of recovered CO 2) compared to oxycombustion, providing optimal operating conditions are chosen.
This contribution is concerned with the experimental and simulative examination of a hybrid process consisting of a membrane stage for gas separation and a chemical absorption unit for the removal of CO 2 from gas streams. The feed stream to the separation process is the product of the oxidative coupling of methane (OCM) and contains 26 vol% CO 2 in addition to methane, ethylene, and ethane. For the investigation of the process a mini-plant was built at TU Berlin, operating at feed flow rates of up to 25 Nm 3 /h and pressures up to 32 bar. The mini-plant closely mimics industrial operating scenarios. The potential for the reduction of energy, equipment, and installation cost by using membranes is assessed and evaluated experimentally in comparison with state of the art separation techniques. The benchmark in CO 2 gas purification for high purity and high selectivity consists of a chemical absorption process using an amine-based absorbent. The mini-plant shows an energetic optimum at 5 MJ/kg CO2 for the absorption using 30 wt% monoethanolamine (MEA) to achieve a CO 2 removal from the feed gas of 90%. In addition, 37 wt% Nmethyldiethanolamine (MDEA) with 3 wt% piperazine as an activator are examined. The ternary amine is an example for a high performance absorbent showing energetic advantages in the regeneration step. Experimental studies in the mini-plant resulted in a specific energy demand of 3.47 MJ/kg CO2 . Installing a HZG 1 gas permeation module upstream to the absorption unit leads to a reduction of the specific energy demand per kilogram of captured CO 2 of 40%. The module is equipped with MATRIMID ® membranes and is found to reduce the CO 2 content of the feed gas to 17 vol%. Hence, equipment cost reductions in the absorption process by requiring fewer theoretical plates in both columns, and in general smaller utility equipment, i.e. heat exchangers and pumps, can also be achieved. Furthermore, a 1 HZG: Helmholtz-Zentrum Geesthacht Centre for Materials and Coastal Research, formerly known as GKSS, http://www.hzg.de/index.html.en decrease of the flow rate of the absorbent by 20% is attained. The described hybrid process configurations shows a stable separation performance during 500 operating hours with more than 50 start-ups and shutdowns at the investigated feed pressures of 5, 10, and 32 bar respectively. In order to address the somewhat lower product recovery of the hybrid process, two stage membrane arrangements will be assessed. These arrangements allow for the combination of different CO 2 -selective membrane materials in order to minimize the additional gas compression costs of such an installation. Two sequentially connected membranes, in comparison to a single stage, provide more options for optimization. Based on the simulation for the mini-plant level, ethylene recovery could be increased while allowing for the same CO 2 removal rate as in a one-stage system.
Progress and trends in CO 2 capture/separation technologies: A review
Coal-fired thermal power plants are the major source of CO 2 emission among fossil fuel power plants. In thermal power plants, coal combustion produces flue gas containing a number of gases including hazardous pollutants, such as CO 2 , mercury (Hg), sulfur dioxide (SO 2 ), and oxides of nitrogen (NO x ). Among all, CO 2 is the largest contributor to global warming. CO 2 capture and separation are therefore essential to keep the environment safe and secure. The present paper delineates the existing literature to examine the current status of various methods and technologies used for CO 2 capture and separation from thermal power plant flue gas. Various emerging technologies like, chemical-looping combustion, integrated gasification combined cycle, enzyme based separation, dual-alkali absorption approach, facilitated transport membrane, hydrate based separations, mixed matrix membrane and, calcium looping are also thoroughly discussed.