共查询到20条相似文献,搜索用时 15 毫秒
1.
Power generation from fossil fuel-fired power plants is the largest single source of CO2 emissions. Post combustion capture via chemical absorption is viewed as the most mature CO2 capture technique. This paper presents a study of the post combustion CO2 capture with monoethanolamine (MEA) based on dynamic modelling of the process. The aims of the project were to compare two different approaches (the equilibrium-based approach versus the rate-based approach) in modelling the absorber dynamically and to understand the dynamic behaviour of the absorber during part load operation and with disturbances from the stripper. A powerful modelling and simulation tool gPROMS was chosen to implement the proposed work. The study indicates that the rate-based model gives a better prediction of the chemical absorption process than the equilibrium-based model. The dynamic simulation of the absorber indicates normal absorber column operation could be maintained during part load operation by maintaining the ratio of the flow rates of the lean solvent and flue gas to the absorber. Disturbances in the CO2 loading of the lean solvent to the absorber significantly affect absorber performance. Further work will extend the dynamic modelling to the stripper for whole plant analysis. 相似文献
2.
Among carbon capture and storage (CCS), the post-combustion capture of carbon dioxide (CO2) by means of chemical absorption is actually the most developed process. Steady state process simulation turned out as a powerful tool for the design of such CO2 scrubbers. Besides steady state modeling, transient process simulations deliver valuable information on the dynamic behavior of the system. Dynamic interactions of the power plant with the CO2 separation plant can be described by such models. Within this work a dynamic process simulation model of the absorption unit of a CO2 separation plant was developed. For describing the chemical absorption of CO2 into an aqueous monoethanolamine solution a rate based approach was used. All models were developed within the Aspen Custom Modeler® simulation environment. Thermo physical properties as well as transport properties were taken from the electrolyte non-random-two-liquid model provided by the Aspen Properties® database. Within this work two simulation cases are presented. In a first simulation the inlet temperature of the flue gas and the lean solvent into the absorber column was changed. The results were validated by using experimental data from the CO2SEPPL test rig located at the Dürnrohr power station. In a second simulation the flue gas flow to the separation plant was increased. Due to the unavailability of experimental data a validation of the results from the second simulation could not be achieved. 相似文献
3.
In the work presented in this paper, an alternative process concept that can be applied as retrofitting option in coal-fired power plants for CO2 capture is examined. The proposed concept is based on the combination of two fundamental CO2 capture technologies, the partial oxyfuel mode in the furnace and the post-combustion solvent scrubbing. A 330 MWel Greek lignite-fired power plant and a typical 600 MWel hard coal plant have been examined for the process simulations. In a retrofit application of the ECO-Scrub technology, the existing power plant modifications are dominated by techno-economic restrictions regarding the boiler and the steam turbine islands. Heat integration from processes (air separation, CO2 compression and purification and the flue gas treatment) can result in reduced energy and efficiency penalties. In the context of this work, heat integration options are illustrated and main results from thermodynamic simulations dealing with the most important features of the power plant with CO2 capture are presented for both reference and retrofit case, providing a comparative view on the power plant net efficiency and energy consumptions for CO2 capture. The operational characteristics as well as the main figures and diagrams of the plant’s heat balances are included. 相似文献
4.
Jozsef GáspárAna-Maria Cormo? 《Computers & Chemical Engineering》2011,35(10):2044-2052
The paper evaluates, by modeling and simulation, carbon dioxide capture in aqueous solution of mono-ethanolamine (MEA) in packed absorption columns to be used in power sector for reducing greenhouse gas emissions. The mathematical model of carbon dioxide absorption and rich amine regeneration process includes transfer processes: mass and heat to study the coupled effect of temperature and concentration on the rate of absorption. The reaction kinetics and the vapor-liquid equilibrium (VLE) are other important parts of the model. The present dynamic mathematical model can be used to analyze the absorption rate, to understand the micro level interaction of various processes taking place inside the absorption and desorption column, and to improve the overall design of the system.The aim of the project was to validate the absorber and desorber models, as well as to understand the dynamic behavior of the whole capture-regeneration steps. 相似文献
5.
Solvent-based post-combustion capture technologies have great potential for CO2mitigation in traditional coal-fired power plants.Modelling and simulation provide a low-cost opportunity to evaluate performances and guide flexible operation.Composed by a series of partial differential equations,first-principle post-combustion capture models are computationally expensive,which limits their use in real time process simulation and control.In this study,we propose a first-principle approach to develop the basic structure of a reduced-order model and then the dominant factor is used to fit properties and simplify the chemical and physical process,based on which a universal and hybrid post-combustion capture model is established.Model output at steady state and trend at dynamic state are validated using experimental data obtained from the literature.Then,impacts of liquidto-gas ratio,reboiler power,desorber pressure,tower height and their combination on the absorption and desorption effects are analyzed.Results indicate that tower height should be designed in conjunction with the flue gas flow,and the gas-liquid ratio can be optimized to reduce the reboiler power under a certain capture target. 相似文献
6.
The drive for efficiency improvements in post-combustion CO2 capture (PCC) technologies continues to grow, with recent attention being directed towards flexible operation of PCC plants. However, there is a lack of research into the effect of process disturbances when operating flexibly, justifying a need for validated dynamic models of the PCC process. This review critically examines the dynamic PCC process models developed to date and analyses the different approaches used, as well as the model complexity and their limitations. Dynamic process models coupled with economic analysis will play a crucial role in process control and optimisation. Also discussed are key areas that need to be addressed in future dynamic models, including the lack of reliable dynamic experimental data for their validation, development of feasible flexible operation and process control strategies, as well as process optimisation by integrating accurate process models with established economic analysis tools. 相似文献
7.
A rate-based process model for the reactive absorption of carbon dioxide (CO2) from a gas mixture into an aqueous monoethanolamine (MEA) solution in a packed column is developed. The model is based on the fast second-order kinetics for the CO2-MEA reactions and takes into account the mass transfer resistances. The heat effects associated with the absorption and chemical reaction are included through energy balances in the gas and liquid phases. Appropriate correlations for the key thermodynamic and transport properties and for the gas-liquid mass transfer are incorporated into the model to ensure reliable predictions. The model predictions are validated by simulating a series of experiments conducted in pilot and industrial scale absorption columns with random and structured packings reported in the literature. Comparisons between the simulation results and the experimental data reveal good quality predictions of the gas phase CO2 and MEA concentrations and the liquid temperature along the column height. The sensitivity studies reveal that the correlations for the gas- and liquid-film mass transfer coefficients given by Onda et al. (1968) provide better predictions than the penetration theory of Higbie (1935) and the correlation of Bravo et al. (1985). 相似文献
8.
Nestor RodríguezSergio Mussati Nicolas Scenna 《Chemical Engineering Research and Design》2011,89(9):1763-1773
This paper presents optimal operating conditions for the post-combustion CO2 capture process utilizing aqueous amine solutions obtained using a process simulator (HYSYS). Three alkanolamine solutions (Methyldiethanolamine MDEA, DiEthanolAmine DEA and MDEA-DEA mixture) are considered to study the performance of the capture process.The design problem addressed in this paper requires specifying the optimal operating conditions (inlet and outlet temperature of the lean solution stream on the absorber, CO2 loading, amine composition and flow rates, among others) to achieve the given CO2 emission targets at a minimum total annual cost. A detailed objective function including total operating costs and investment is considered.The influence of the variation of CO2 reduction targets and the mixing proportion of amines on the total annual cost is analyzed in detail. Numerical results are presented and discussed using different case studies.The results demonstrate that process simulators can be used as a powerful tool not only to simulate but also to optimize the most important design parameters of the post-combustion CO2 capture process. 相似文献
9.
Australian power generators produce approximately 170 TWh per annum of electricity using black and brown coals that accounts for 170 Mtonne of CO2 emissions per annum or over 40% of anthropogenic CO2 emissions in Australia. This paper describes the results of a techno-economic evaluation of liquid absorption based post-combustion capture (PCC) processes for both existing and new pulverised coal-fired power stations in Australia. The overall process designs incorporate both the case with continuous capture and the case with the flexibility to switch a CO2 capture plant on or off depending upon the demand and market price for electricity, and addresses the impact of the presently limited emission controls on the process cost. The techno-economic evaluation includes both air and water cooled power and CO2 capture plants, resulting in cost of power generation for the situations without and with PCC. Whilst existing power plants in Australia are all water cooled sub-critical designs, the new power plants are deemed to range from supercritical single reheat to ultra-supercritical double reheat designs, with a preference for air-cooling. The process evaluation also includes a detailed sensitivity analysis of the thermodynamic properties of liquid absorbent for CO2 on the overall costs. The results show that for a meaningful decrease in the efficiency and cost penalties associated with the post combustion CO2 capture, a novel liquid sorbent will need to have heat of absorption/desorption, sensible heat and heat of vaporisation around 50% less in comparison with 30% (w/w) aqueous MEA solvent. It also shows that the impact of the capital costs of PCC processes is quite large on the added cost of generation. The results can be used to prioritise PCC research in an Australian context. 相似文献
10.
Ashleigh Cousins Leigh T. WardhaughPaul H.M. Feron 《Chemical Engineering Research and Design》2011,89(8):1237-1251
The energy penalty associated with solvent based capture of CO2 from power station flue gases can be reduced by incorporating process flow sheet modifications into the standard process. A review of modifications suggested in the open and patent literature identified several options, primarily intended for use in the gas processing industry. It was not immediately clear whether these options would have the same benefits when applied to CO2 capture from near atmospheric pressure combustion flue gases. Process flow sheet modifications, including split flow, rich split, vapour recompression, and inter-stage cooling, were therefore modelled using a commercial rate-based simulation package. The models were completed for a Queensland (Australia) based pilot plant running on 30% MEA as the solvent. The preliminary modelling results showed considerable benefits in reducing the energy penalty of capturing CO2 from combustion flue gases. Further work will focus on optimising and validating the most relevant process flow sheet modifications in a pilot plant. 相似文献
11.
M. Wang A. LawalP. Stephenson J. SiddersC. Ramshaw 《Chemical Engineering Research and Design》2011,89(9):1609-1624
Global concentration of CO2 in the atmosphere is increasing rapidly. CO2 emissions have an impact on global climate change. Effective CO2 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 post-combustion 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. 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. 相似文献
12.
Fossil fuel power plants are one of the major sources of electricity generation, although invariably release greenhouse gases. Due to international treaties and countries regulations, CO2 emissions reduction is increasingly becoming key in the generators’ economics. NGCC power plants constitute a widely used generation technology, from which CO2 capture through a post-combustion and MEA absorption option constitutes a technological challenge due to the low concentration of pollutants in the flue gas and the high energy requirements of the sequestration process. 相似文献
13.
Patricia Mores 《Chemical Engineering Research and Design》2011,89(9):1587-1599
This paper deals with the modeling and optimization of the chemical absorption process to CO2 removal using monoethanolamine (MEA) aqueous solution. Precisely, an optimization mathematical model is proposed to determine the best operating conditions of the CO2 post-combustion process in order to maximize the CO2 removal efficiency. Certainly, the following two objective functions are considered for maximization: (a) ratio between the total absorbed CO2 and the total heating and cooling utilities and (b) ratio between total absorbed CO2 and the total amine flow-rate.Temperature, composition and flow-rate profiles of the aqueous solution and gas streams along the absorber and regenerator as well as the reboiler and condenser duties are considered as optimization variables. The number of trays or height equivalent to a theoretical plate (HETP) on the absorber and regenerator columns as well as the CO2 composition in flue gas are treated as model parameters. Correlations used to compute physical-chemical properties of the aqueous amine solution are taken from different specialized literature and are valid for a wide range of operating conditions. For the modeling, both columns (absorber and regenerator) are divided into a number of segments assuming that liquid and gas phases are well mixed.GAMS (General Algebraic Modeling System) and CONOPT are used, respectively, to implement and to solve the resulting mathematical model.The robustness and computational performance of the proposed model and a detailed discussion of the optimization results will be presented through different case studies. Finally, the proposed model cannot only be used as optimizer but also as a simulator by fixing the degree of freedom of the equation system. 相似文献
14.
Amine and other liquid solvent CO2 capture systems capture have historically been developed in the oil and gas industry with a different emphasis to that expected for fossil fuel power generation with post-combustion capture. These types of units are now being adapted for combustion flue gas scrubbing for which they need to be designed to operate at lower CO2 removal rates - around 85-90% and to be integrated with CO2 compression systems. They also need to be operated as part of a complete power plant with the overall objective of turning fuel into low-carbon electricity.The performance optimisation approach for solvents being considered for post-combustion capture in power generation therefore needs to be updated to take into account integration with the power cycle and the compression train. The most appropriate metric for solvent assessment is the overall penalty on electricity output, rather than simply the thermal energy of regeneration of the solvent used.Methodologies to evaluate solvent performance that have been reported in the literature are first reviewed. The results of the model of a steam power cycle integrated with the compression system focusing on key parameters of the post-combustion capture plant - solvent energy of regeneration, solvent regeneration temperature and desorber pressure - are then presented. The model includes a rigorous thermodynamic integration of the heat available in the capture and compression units into the power cycle for a range of different solvents, and shows that the electricity output penalty of steam extraction has a strong dependence on solvent thermal stability and the temperature available for heat recovery. A method is provided for assessing the overall electricity output penalty (EOP), expressed as total kWh of lost output per tonne of CO2 captured including ancillary power and compression, for likely combinations of these three key post-combustion process parameters. This correlation provides a more representative method for comparing post-combustion capture technology options than the use of single parameters such as solvent heat of regeneration. 相似文献
15.
This paper proposes a novel power cycle system composed of chemical recuperative cycle with CO2–NG (natural gas) reforming and an ammonia absorption refrigeration cycle. In which, the heat is recovered from the turbine exhaust to drive CO2–NG reformer firstly, and then lower temperature heat from the turbine exhaust is provided with the ammonia absorption refrigeration system to generate chilled media, which is used to cool the turbine inlet gas except export. In this paper, a detailed thermodynamic analysis is carried out to reveal the performance of the proposed cycle and the influence of key parameters on performance is discussed. Based on 1 kg s−1 of methane feedstock and the turbine inlet temperature of 1573 K, the simulation results shown that the optimized net power generation efficiency of the cycle rises up to 49.6% on the low-heating value and the exergy efficiency 47.9%, the new cycle system reached the net electric-power production 24.799 MW, the export chilled load 0.609 MW and 2.743 kg s−1 liquid CO2 was captured, achieved the goal of CO2 and NOx zero-emission. 相似文献
16.
In order to reduce the CO2 emission from the coal-fired power plants, O2/CO2 recycle combustion (Oxy-combustion) technique has been proposed through combining a conventional combustion process with a cryogenic air separation process. The technique is capable of enriching CO2 concentration and then allowing CO2 sequestration in an efficient and energy-saving way. Taking into account the CO2 taxation and CO2 sale, the paper evaluates the economic feasibility of Oxy-combustion plants retrofitted from two typical existing conventional coal-fired power plants (with capacities of 2 × 300 MW and 2 × 600 MW, respectively) with Chinese data. The cost of electricity (COE) and the CO2 avoidance cost (CAC) are also considered in the evaluation. The COE of the retrofitted Oxy-combustion plant is nearly the same as that of the corresponding conventional plant if the unit price of CO2 sale reaches 17-22 $/t (different cases). The CAC of the retrofitted 2 × 300 MW Oxy-combustion plant is 1-3 $/t bigger than that of the retrofitted 2 × 600 MW Oxy-combustion plant. Supercritical plants are more economical and appropriate for Oxy-combustion retrofit. The result indicates that Oxy-combustion technique is not only feasible for CO2 emission control based on existing power plants but is also cost-effective. 相似文献
17.
This paper describes a series of experiments conducted with natural gas in air and in mixtures of oxygen and recycled flue gas, termed O2/CO2 recycle combustion. The objective is to enrich the flue gas with CO2 to facilitate its capture and sequestration. Detailed measurements of gas composition, flame temperature and heat flux profiles were taken inside CANMET's 0.3 MWth down-fired vertical combustor fitted with a proprietary pilot scale burner. Flue gas composition was continuously monitored. The effects of burner operation, including swirling of secondary stream and air staging, on flame characteristics and NOx emissions were also studied. The results of this work indicate that oxy-gas combustion techniques based on O2/CO2 combustion with flue gas recycle offer excellent potential for retrofit to conventional boilers for CO2 emission abatement. Other benefits of the technology include considerable reduction and even elimination of NOx emissions, improved plant efficiency due to lower gas volume and better operational flexibility. 相似文献
18.
CO2 capture systems based on the carbonation/calcination loop have gained rapid interest due to promising carbonator CO2 capture efficiency, low sorbent cost and no flue gases treatment is required before entering the system. These features together result in a competitively low cost CO2 capture system. Among the key variables that influence the performance of these systems and their integration with power plants, the carbonation conversion of the sorbent and the heat requirement at calciner are the most relevant. Both variables are mainly influenced by CaO/CO2 ratio and make-up flow of solids. New sorbents are under development to reduce the decay of their carbonation conversion with cycles. The aim of this study is to assess the competitiveness of new limestones with enhanced sorption behaviour applied to carbonation/calcination cycle integrated with a power plant, compared to raw limestone. The existence of an upper limit for the maximum average capture capacity of CaO has been considered. Above this limit, improving sorbent capture capacity does not lead to the corresponding increase in capture efficiency and, thus, reduction of CO2 avoided cost is not observed. Simulations calculate the maximum price for enhanced sorbents to achieve a reduction in CO2 removal cost under different process conditions (solid circulation and make-up flow). The present study may be used as an assessment tool of new sorbents to understand what prices would be competitive compare with raw limestone in the CO2 looping capture systems. 相似文献
19.
Gongkui Xiao Penny Xiao Andrew Hoadley Paul Webley 《Frontiers of Chemical Science and Engineering》2021,15(3):483
This study explored the feasibility of integrating an adsorption and solvent scrubbing process for post-combustion CO2 capture from a coal-fired power plant. This integrated process has two stages: the first is a vacuum swing adsorption (VSA) process using activated carbon as the adsorbent, and the second stage is a solvent scrubber/stripper system using monoethanolamine (30 wt-%) as the solvent. The results showed that the adsorption process could enrich CO2 in the flue gas from 12 to 50 mol-% with a CO2 recovery of >90%, and the concentrated CO2 stream fed to the solvent scrubber had a significantly lower volumetric flowrate. The increased CO2 concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber, bringing the size of the absorber from uneconomically large to readily achievable domain. In addition, the VSA process could also remove most of the oxygen initially existed in the feed gas, alleviating the downstream corrosion and degradation problems in the absorption section. The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO2 capture and thus accelerate the deployment of such technologies to reduce carbon emissions. 相似文献
20.
David Grainger 《Fuel》2008,87(1):14-24
Published data for an operating power plant, the ELCOGAS 315 MWe Puertollano plant, has been used as a basis for the simulation of an integrated gasification combined cycle process with CO2 capture. This incorporated a fixed site carrier polyvinylamine membrane to separate the CO2 from a CO-shifted syngas stream. It appears that the modified process, using a sour shift catalyst prior to sulphur removal, could achieve greater than 85% CO2 recovery at 95 vol% purity. The efficiency penalty for such a process would be approximately 10% points, including CO2 compression. A modified plant with CO2 capture and compression was calculated to cost €2320/kW, producing electricity at a cost of 7.6 € cents/kWh and a CO2 avoidance cost of about €40/tonne CO2. 相似文献