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.
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
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.
C.F. Martín 《Fuel》2011,90(5):2064-556
Different types of phenolic resins were used as precursor materials to prepare adsorbents for the separation of CO2 in pre-combustion processes. In order to obtain highly microporous carbons with suitable characteristics for the separation of CO2 and H2 under high pressure conditions, phenol-formaldehyde resins were synthesised under different conditions. Resol resins were obtained by using an alkaline environment while Novolac resins were synthesised in the presence of acid catalysts. In addition, two organic additives, ethylene glycol (E) and polyethylene glycol (PE) were included in the synthesis. The phenolic resins thus prepared were carbonised at different temperatures and then physically activated with CO2. The carbons produced were characterised in terms of texture, chemical composition and surface chemistry. Maximum CO2 adsorption capacities at atmospheric pressure were determined in a thermogravimetric analyser. Values of up to 10.8 wt.% were achieved. The high-pressure adsorption of CO2 at room temperature was determined in a high-pressure magnetic suspension balance. The carbons tested showed enhanced CO2 uptakes at high pressures (up to 44.7 wt.% at 25 bar). In addition, it was confirmed that capture capacities depend highly on the microporosity of the samples, the narrow micropores (pore widths of less than 0.7 nm) being the most active in CO2 adsorption at atmospheric pressure. The results presented in this work suggest that phenol-formaldehyde resin-derived activated carbons, particularly those prepared with the addition of ethylene glycol, show great potential as adsorbents for pre-combustion CO2 capture. 相似文献
5.
Vasilije Manovic 《Fuel》2011,90(1):233-239
CaO-based pellets supported with aluminate cements show superior performance in carbonation/calcination cycles for high-temperature CO2 capture. However, like other CaO-based sorbents, their CO2 carrying activity is reduced after increasing numbers of cycles under high-temperature, high-CO2 concentration conditions. In this work the feasibility of their reactivation by steam or water and remaking (reshaping) was investigated. The pellets, prepared from three limestones, Cadomin and Havelock (Canada) and Katowice (Poland, Upper Silesia), were tested in a thermogravimetric analyzer (TGA). The cycles were performed under realistic CO2 capture conditions, which included calcination in 100% CO2 at temperatures up to 950 °C. Typically, after 30 cycles, samples were hydrated for 5 min with saturated steam at 100 °C in a laboratory steam reactor (SR). Moreover, larger amounts of pellets were cycled in a tube furnace (TF), hydrated with water and reshaped, and tested to determine their CO2 capture activity in the TGA. It was found that, after the hydration stage, pellets recovered their activity, and more interestingly, pellets that had experienced a longer series of cycles responded more favorably to reactivation. Moreover, it was found that conversion of pellets increased after about 70 cycles (23%), reaching 33% by about cycle 210, with no reactivation step. Scanning electron microscope (SEM) analyses showed that the morphology of the low-porosity shell formed at the pellet surface during cycles, which limits conversion, was eliminated after a short period (5 min) of steam hydration. The nitrogen physisorption analyses (BET, BJH) of reshaped spent pellets from cycles in the TF confirmed that sorbent surface area and pore size distribution were similar to those of the original pellets. The main alumina compound in remade pellets as determined by XRD was mayenite (Ca12Al14O33). These results showed that, with periodic hydration/remaking steps, pellets can be used for extended times in CO2 looping cycles, regardless of capture/regeneration conditions. 相似文献
6.
CO2 capture by adsorption with nitrogen enriched carbons 总被引:2,自引:0,他引:2
M.G. Plaza 《Fuel》2007,86(14):2204-2212
The success of CO2 capture with solid sorbents is dependent on the development of a low cost sorbent with high CO2 selectivity and adsorption capacity. Immobilised amines are expected to offer the benefits of liquid amines in the typical absorption process, with the added advantages that solids are easy to handle and that they do not give rise to corrosion problems. In this work, different alkylamines were evaluated as a potential source of basic sites for CO2 capture, and a commercial activated carbon was used as a preliminary support in order to study the effect of the impregnation. The amine coating increased the basicity and nitrogen content of the carbon. However, it drastically reduced the microporous volume of the activated carbon, which is chiefly responsible for CO2 physisorption, thus decreasing the capacity of raw carbon at room temperature. 相似文献
7.
Optimization of CO2 capture process with aqueous amines using response surface methodology 总被引:1,自引:0,他引:1
Aroonsri NuchitprasittichaiSelen Cremaschi 《Computers & Chemical Engineering》2011,35(8):1521-1531
Amine is one of candidate solvents that can be used for CO2 recovery from the flue gas by conventional chemical absorption/desorption process. In this work, we analyzed the impact of different amine absorbents and their concentrations, the absorber and stripper column heights and the operating conditions on the cost of CO2 recovery plant for post-combustion CO2 removal. For each amine solvent, the optimum number of stages for the absorber and stripper columns, and the optimum absorbent concentration, i.e., the ones that give the minimum cost for CO2 removed, is determined by response surface optimization. Our results suggest that CO2 recovery with 48 wt% DGA requires the lowest CO2 removal cost of $43.06/ton of CO2 with the following design and operating conditions: a 20-stage absorber column and a 7-stage stripper column, 26 m3/h of solvent circulation rate, 1903 kW of reboiler duty, and 99°C as the regenerator-inlet temperature. 相似文献
8.
Processes based upon solid sorbents are currently under consideration for post-combustion CO2 capture. Twenty-four different sorbent materials were examined on a laboratory scale in a cyclic temperature swing adsorption/regeneration CO2 capture process in simulated coal combustion flue gas. Ten of these materials exhibited significantly lower theoretical regeneration energies compared to the benchmark aqueous monoethanolamine, supporting the hypothesis that CO2 capture processes based upon solids may provide cost benefits over solvent-based processes. The best performing materials were tested on actual coal-fired flue gas. The supported amines exhibited the highest working CO2 capacities, although they can become poisoned by the presence of SO2. The carbon-based materials showed excellent stability but were generally categorized as having low CO2 capacities. The zeolites worked well under dry conditions, but were quickly poisoned by the presence of moisture. Although no one type of material is without concerns, several of the materials tested have theoretical regeneration energies significantly lower than that of the industry benchmark, warranting further development research. 相似文献
9.
To demonstrate process feasibility of in situ CO2 capture from combustion of fossil fuels using Ca-based sorbent looping technology, a flexible atmospheric dual fluidized bed combustion system has been constructed. Both reactors have an ID of 100 mm and can be operated at up to 1000 °C at atmospheric pressure. This paper presents preliminary results for a variety of operating conditions, including sorbent looping rate, flue gas stream volume, CaO/CO2 ratio and combustion mode for supplying heat to the sorbent regenerator, including oxy-fuel combustion of biomass and coal with flue gas recirculation to achieve high-concentration CO2 in the off-gas. It is the authors' belief that this study is the first demonstration of this technology using a pilot-scale dual fluidized bed system, with continuous sorbent looping for in situ CO2 capture, albeit at atmospheric pressure. A multi-cycle test was conducted and a high CO2 capture efficiency (> 90%) was achieved for the first several cycles, which decreased to a still acceptable level (> 75%) even after more than 25 cycles. The cyclic sorbent was sampled on-line and showed general agreement with the features observed using a lab-scale thermogravimetric analysis (TGA) apparatus. CO2 capture efficiency decreased with increasing number of sorbent looping cycles as expected, and sorbent attrition was found to be another significant factor to be limiting sorbent performance. 相似文献
10.
Chun Zhang Tian-Long Zhai Jing-Jing Wang Zhen Wang Jun-Min Liu Bien Tan Xiang-Liang Yang Hui-Bi Xu 《Polymer》2014
A series of triptycene-based porous polyimides (STPIs) were synthesized by condensation polymerizations. The structure and properties of these STPIs were characterized by IR, solid 13C NMR, powder XRD, SEM, TEM and gas absorption. As STPI-2 with the high thermal stability, they display excellent adsorption ability to CO2 uptake capacity of 14.6 wt% (273 K), and exhibit the high selectivity of CO2/N2 of 107. 相似文献
11.
Ugochukwu E. AronuHallvard F. Svendsen 《Chemical Engineering Research and Design》2011,89(8):1197-1203
A method was developed for selection of promising solvents based on CO2 absorption experiments at 40 °C and 9.5 kPa CO2 partial pressure followed by desorption of the same solvents at 80 °C down to 1.0 kPa CO2 partial pressure. Experiments conducted on 13 solvent systems under atmospheric conditions revealed the solvents absorption and desorption characteristics and these were compared with 1.0 M, 2.5 M, 5.0 M and 10.0 M MEA. Results showed that absorption or stripping data alone were not sufficient in making robust solvent selection decisions, and that combined data analysis was necessary. 1.0 M tetraethylenepentamine (TEPA) and 5.0 M MEA showed the best performance in terms of absorption rate. 1.5 M Bis-(3-dimethylaminopropyl) amine (TMBPA) was easy to desorb, has high absorption capacity; and when promoted it showed the best performance in terms of CO2 carrying capacity. At the test conditions, 1.5 M TMBPA promoted with 1.0 M PZ showed the best potential for efficient CO2 removal at reduced cost of all systems tested. Its cyclic capacity in mol CO2/mol amine was found to be 70% higher than that of 5 M MEA. 相似文献
12.
M.G. Plaza C. Pevida B. Arias J. Fermoso M.D. Casal C.F. Martín F. Rubiera J.J. Pis 《Fuel》2009,88(12):2442-2447
In this work a series of carbon adsorbents were prepared from a low-cost biomass residue, olive stones. Two different approaches were studied: activation with CO2 and heat treatment with gaseous ammonia. The results showed that both methods are suitable for the production of adsorbents with a high CO2 adsorption capacity, and their potential application in VSA or TSA systems for postcombustion CO2 capture. It was found that the presence of nitrogen functionalities enhances CO2 adsorption capacity, especially at low partial pressures. 相似文献
13.
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
14.
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
15.
This study examines the CO2 capture behavior of KMnO4-doped CaO-based sorbent during the multiple calcination/carbonation cycles. The cyclic carbonation behavior of CaCO3 doped with KMnO4 and the untreated CaCO3 was investigated. The addition of KMnO4 improves the cyclic carbonation rate of the sorbent above carbonation time of 257 s at each carbonation cycle. When the mass ratio of KMnO4/CaCO3 is about 0.5-0.8 wt.%, the sorbent can achieve an optimum carbonation conversion during the long-term cycles. The carbonation temperature of 660-710 °C is beneficial to cyclic carbonation of KMnO4-doped CaCO3. The addition of KMnO4 improves the long-term performance of CaCO3, resulting in directly measured conversion as high as 0.35 after 100 cycles, while the untreated CaCO3 retains conversion less than 0.16 at the same reaction conditions. The addition of KMnO4 decreases the surface area and pore volume of CaCO3 after 1 cycle, but it maintains the surface area and pores between 26 nm and 175 nm of the sorbent during the multiple cycles. Calculation reveals that the addition of KMnO4 improves the CO2 capture efficiency significantly using a CaCO3 calcination/carbonation cycle and decreases the amount of the fresh sorbent. 相似文献
16.
M. Lupion B. NavarreteP. Otero V.J. Cortés 《Chemical Engineering Research and Design》2011,89(9):1494-1500
Energy projections made by the World Energy Council, the International Energy Agency (IEA) and the US Energy Information Administration give similar pictures of the dominant role of fossil fuel in the future primary energy global demand and the necessity of incorporating CCS Technologies as part of the portfolio of solutions to reach the target world emission reduction in the coming years. Without CCS, CO2 emission levels by 2050 are expected to increase by 70%.One of the most relevant initiatives for the deployment of CCS technologies is promoted by the Spanish Government through the institution Fundacion Ciudad de la Energia (CIUDEN). CIUDEN is developing a complete programme focusing on the development of CCT and CCS technologies in Europe.CIUDEN's CO2 capture programme includes the construction and operation of a Technology Development Plant (TDP) in NW Spain (El Bierzo). The construction of the installation started in November 2008 and incorporates the following technologies: fuel preparation system, pulverised coal boiler (20 MWth), circulating fluidized bed boiler (30 MWth), biomass gasifier (3 MWth), flue gas cleaning train for NOx, dust and SOx, and CO2 processing unit.This paper describes CIUDEN's TDP for CO2 capture, focusing on the particularities of the installation and design, and especially on the PC unit and equipment required for its operation. The experimental programme currently under way is also described.Results are expected to be an extraordinary advance in the development and strengthening of CCT and CCS technologies, particularly oxycombustion. 相似文献
17.
Hongkun He Wenwen Li Melissa Lamson Mingjiang Zhong Dominik Konkolewicz Chin Ming Hui Karin Yaccato Timothy Rappold Glenn Sugar Nathaniel E. David Krishnan Damodaran Sittichai Natesakhawat Hunaid Nulwala Krzysztof Matyjaszewski 《Polymer》2014
A series of porous polymers with different pore volumes, pore sizes, and crosslinking densities were synthesized by high internal phase emulsion (HIPE) polymerization. The crosslinked polymerized HIPEs (polyHIPEs) were formed by the copolymerization of 4-vinylbenzyl chloride and divinylbenzene using water droplets in conventional or Pickering HIPEs as the templates. These porous materials were further modified by quaternization and ion exchange to introduce quaternary ammonium hydroxide groups. The resulting polyHIPEs were utilized as sorbents for reversible CO2 capture from air using the humidity swing. The effect of pore structure on the CO2 adsorption and desorption processes was studied. The polyHIPEs containing large pores and interconnected porous structures showed improved swing sizes and faster adsorption/desorption kinetics of CO2 compared to a commercial Excellion membrane with similar functional groups. 相似文献
18.
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
19.
Ying-jie Li Chang-sui ZhaoLun-bo Duan Cai LiangQing-zhao Li Wu ZhouHui-chao Chen 《Fuel Processing Technology》2008
The dolomite modified with acetic acid solution was proposed as a CO2 sorbent for calcination/carbonation cycles. The carbonation conversions for modified and original dolomites in a twin fixed-bed reactor system with increasing the numbers of cycles were investigated. The carbonation temperature in the range of 630 °C–700 °C is beneficial to the carbonation reaction of modified dolomite. The carbonation conversion for modified dolomite is significantly higher than that for original sorbent at the same reaction conditions with increasing numbers of reaction cycles. The modified dolomite exhibits a carbonation conversion of 0.6 after 20 cycles, while the unmodified sorbent shows a conversion of 0.26 at the same reaction conditions, which is calcined at 920 °C and carbonated at 650 °C. At the high calcination temperature over 920 °C modified dolomite can maintain much higher conversion than unmodified sorbent. The mean grain size of CaO derived from modified dolomite is smaller than that from original sorbent with increasing numbers of reaction cycles. The calcined modified dolomite possesses greater surface area and pore volume than calcined original sorbent during the multiple cycles. The pore volume and pore area distributions for calcined modified dolomite are also superior to those for calcined unmodified sorbent during the looping cycle. The modified dolomite is proved as a new and promising type of regenerable CO2 sorbent for industrial applications. 相似文献
20.
Mohsen Kianpour Mohammad Amin SobatiShahrokh Shahhosseini 《Chemical Engineering Research and Design》2012
In this work, CO2 capture from the air using dry NaOH sorbents has been studied. The influences of the main operating parameters such as temperature, air humidity, and NaOH loading on the CO2 removal rate have been experimentally investigated using Taguchi method. The results revealed that the appropriate value of the temperature to maximize the rate was in the range of 35–45 °C. A multilayer artificial neural network (ANN) was also used to model the process in order to find the optimal conditions. A procedure reported in the literature was modified and applied to design the ANN model. The model predictions were validated by conducting some more experiments. The experimental results proved the accuracy of the model to predict the optimal conditions. The effects of NaOH particle size and multiple carbonation cycles have also been investigated. 相似文献