基于化学链方式制取O_2-CO_2混合气的实验研究及分析
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摘要
化石燃料燃烧产生的CO_2是最主要的温室气体来源,O_2/CO_2循环燃烧是一项非常有潜力的碳捕集技术,而且特别适合于我国以煤为主的能源结构。O_2/CO_2循环燃烧需要空分制氧,会使常规电站的净效率大幅下降。目前的几种空分制氧方式均是制纯氧,制氧系统投资大,能耗高。针对O_2/CO_2循环燃烧实际所需的仅是O_2浓度为20-40%的O_2-CO_2混合气这一特点,本文研究了采用化学链方式直接制取这种混合气以降低制氧能耗。
采用浸渍担载法制备了钴基制氧剂颗粒,通过XRD分析了颗粒成分,通过SEM观察了颗粒微观结构。在TGA上研究了制氧剂颗粒在不同温度下和不同氧浓度下的吸氧特性以及在CO_2气氛下的解吸特性。实验结果显示制氧剂颗粒不会与CO_2发生反应,吸氧和解吸反应速率较好,通过不同氧浓度下的初始分解温度获取了钴基制氧剂的热力学平衡关系式,采用缩核模型对动力学特性进行了研究并获取了动力学参数。针对钴基制氧剂熔点低可能会发生烧结的质疑,在制氧所需要的高温下进行了150次吸氧解吸循环反应,循环稳定性非常好,没有任何衰减现象。对烟气中的SO_2,NO可能对制氧剂的影响进行了实验验证及理论分析,说明了实际烟气用于解吸过程吹扫气的可行性。
在固定床上交替进行了吸氧和解吸实验,研究了反应温度、空气流量和CO_2吹扫气体流量等因素对吸氧特性和O_2释放特性的影响。在双固定床上采用气路切换的方式,连续12个小时获得O_2浓度在20%以上的O_2-CO_2混合气,验证了连续制氧的可行性。
通过对制氧过程的热力学平衡和热量分析,提出了适合钴基制氧剂的制氧系统和合适的运行参数,利用Aspen软件计算了制氧过程中的功耗和热量,计算结果表明相对于传统的深冷法制氧有很大优势。对制氧过程所需的制氧剂用量进行了评估,从成本和矿物储量方面论证了可行性。
CO_2 emission from the combustion of fossil fuel is the main source of greenhouse gases. Oxy-combustion is a very promising CO_2 capture technology, which is particularly suited to the coal-dominated energy structure of China. However, the net efficiency of power station based on oxy-combustion will significantly decline due to the air separation unit. How to apply oxygen is a key barrier to the implementation of oxy-combustion. Presently all air separation technologies produce pure oxygen, thus have the disadvantages of heavy investment cost and high energy consumption. Based on the fact that an O_2-CO_2 mixed stream with O_2 concentration between 20-40% rather than pure oxygen is needed for oxy-combustion, this paper studied a chemical looping method that directly produces this kind of O_2-CO_2 mixed stream to reduce energy consumption.
Co-based oxygen carrier particles were prepared by dipping method, then XRD were used to study their compositions and SEM were used to observe their micro-structures. TGA experiments were conducted to study their oxygen absorption and desorption characteristics under different temperatures and different O_2 concentrations. The results indicated that this kind of particles did not react with CO_2, and it had quite good react rate for both absorption and desorption process. A relation between O_2 equilibrium pressure and temperature were obtained by thermodynamic calculations and experimental data, and shrinking-core model were used to study the kinetic parameters. Co-based oxygen carrier had been doubted that it’s had low melting point and thus easy to deactivate due to sintering. In reply to this doubt, 150 cycles of absorption and desorption were conducted under high temperatures required by the oxygen process, very high cyclical stability were observed without any deactivation. Experiments and theoretical analyses indicated that the SO_2 and NO in the flue gas would have no effect on Co-based oxygen carrier under process temperatures, thus validated the feasibility to use flue gas as the purge gas.
Absorption and desorption experiments were also conducted in fixed-bed reactor, to study the effects of temperature and gas flow rate on the absorption and desorption characteristics. O_2-CO_2 mixed stream with O_2 concentration above 20% was produced continuously for 12 hours in two parallel fixed-bed reactors using gas switch, validated the feasibility of continuous O_2 production.
O_2 production system and operation parameters suited to Co-based oxygen carrier were proposed based on thermodynamic equilibrium and heat analyses. Then work and heat consumed in the oxygen process were calculated by Aspen, the results showed significant advantage compared with cryogenic oxygen method. The quantity of Co-based oxygen carrier needed for oxygen process was estimated to check the feasibility on costs and mineral reserves.
采用浸渍担载法制备了钴基制氧剂颗粒,通过XRD分析了颗粒成分,通过SEM观察了颗粒微观结构。在TGA上研究了制氧剂颗粒在不同温度下和不同氧浓度下的吸氧特性以及在CO_2气氛下的解吸特性。实验结果显示制氧剂颗粒不会与CO_2发生反应,吸氧和解吸反应速率较好,通过不同氧浓度下的初始分解温度获取了钴基制氧剂的热力学平衡关系式,采用缩核模型对动力学特性进行了研究并获取了动力学参数。针对钴基制氧剂熔点低可能会发生烧结的质疑,在制氧所需要的高温下进行了150次吸氧解吸循环反应,循环稳定性非常好,没有任何衰减现象。对烟气中的SO_2,NO可能对制氧剂的影响进行了实验验证及理论分析,说明了实际烟气用于解吸过程吹扫气的可行性。
在固定床上交替进行了吸氧和解吸实验,研究了反应温度、空气流量和CO_2吹扫气体流量等因素对吸氧特性和O_2释放特性的影响。在双固定床上采用气路切换的方式,连续12个小时获得O_2浓度在20%以上的O_2-CO_2混合气,验证了连续制氧的可行性。
通过对制氧过程的热力学平衡和热量分析,提出了适合钴基制氧剂的制氧系统和合适的运行参数,利用Aspen软件计算了制氧过程中的功耗和热量,计算结果表明相对于传统的深冷法制氧有很大优势。对制氧过程所需的制氧剂用量进行了评估,从成本和矿物储量方面论证了可行性。
CO_2 emission from the combustion of fossil fuel is the main source of greenhouse gases. Oxy-combustion is a very promising CO_2 capture technology, which is particularly suited to the coal-dominated energy structure of China. However, the net efficiency of power station based on oxy-combustion will significantly decline due to the air separation unit. How to apply oxygen is a key barrier to the implementation of oxy-combustion. Presently all air separation technologies produce pure oxygen, thus have the disadvantages of heavy investment cost and high energy consumption. Based on the fact that an O_2-CO_2 mixed stream with O_2 concentration between 20-40% rather than pure oxygen is needed for oxy-combustion, this paper studied a chemical looping method that directly produces this kind of O_2-CO_2 mixed stream to reduce energy consumption.
Co-based oxygen carrier particles were prepared by dipping method, then XRD were used to study their compositions and SEM were used to observe their micro-structures. TGA experiments were conducted to study their oxygen absorption and desorption characteristics under different temperatures and different O_2 concentrations. The results indicated that this kind of particles did not react with CO_2, and it had quite good react rate for both absorption and desorption process. A relation between O_2 equilibrium pressure and temperature were obtained by thermodynamic calculations and experimental data, and shrinking-core model were used to study the kinetic parameters. Co-based oxygen carrier had been doubted that it’s had low melting point and thus easy to deactivate due to sintering. In reply to this doubt, 150 cycles of absorption and desorption were conducted under high temperatures required by the oxygen process, very high cyclical stability were observed without any deactivation. Experiments and theoretical analyses indicated that the SO_2 and NO in the flue gas would have no effect on Co-based oxygen carrier under process temperatures, thus validated the feasibility to use flue gas as the purge gas.
Absorption and desorption experiments were also conducted in fixed-bed reactor, to study the effects of temperature and gas flow rate on the absorption and desorption characteristics. O_2-CO_2 mixed stream with O_2 concentration above 20% was produced continuously for 12 hours in two parallel fixed-bed reactors using gas switch, validated the feasibility of continuous O_2 production.
O_2 production system and operation parameters suited to Co-based oxygen carrier were proposed based on thermodynamic equilibrium and heat analyses. Then work and heat consumed in the oxygen process were calculated by Aspen, the results showed significant advantage compared with cryogenic oxygen method. The quantity of Co-based oxygen carrier needed for oxygen process was estimated to check the feasibility on costs and mineral reserves.
引文
[1] http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf. 2010年11月引自IPCC官网
[2] Simbeck D. CO_2 mitigation economics for existing coal-fired power plants. Proceedings of First National Conference on Carbon Sequestration. Washington. D.C., US, 2001
[3] Andersson K, Birkestad H, Maksinen P, Johnsson F, Str?mberg L, Lyngfeldt A. An 865 MW lignite fired CO_2 free power plant - a technical feasibility study. Proceedings of GHGT6. Kyoto, Japan, 2002
[4] Singh D, Croiset E, Douglas, et al. Techno-economic study of CO_2 capture from an existing coal-fired power plant: MEA scrubbing vs. O_2/CO_2 recycle combustion. Energy Conversion and Management. 2003, 44: 3073-3091
[5]米翠丽.富氧燃煤锅炉设计研究及其技术经济性分析:[博士学位论文].河北:华北电力大学, 2010
[6] Wall T, Jianglong T. Coal fired oxy fuel technology status and progress to deployment. 34th International Technical Conference on Coal Utilization & Fuel Systems. Florida, USA: Coal Technology Association, 2009
[7]张阳,王湛,纪树兰.富氧技术及其应用.北京:化学工业出版社, 2005
[8] http://www.encapco2.org/technoHTOGPC.html
[9] Herzberg G and Jungen C. Rydberg series and ionization potential of the H2 molecule. Journal of Molecular Spectroscopy. 1972, 41:425-486
[10]李杰.新型紧凑结构四塔变压吸附空分制氧装置研究:[硕士学位论文].天津:天津大学化工学院,2003
[11]韩跃斌,王一平,边守军等.变压吸附(PSA)空气分离工艺技术进展.天然气化工. 1999, 24:36-41
[12] Shah M, Hassel B, Christie M, Li J. CO_2 capture by membrane based oxy-fuel boiler. Proceedings of the 2006 Conference on Carbon Capture and Sequestration, Alexandria, VA, 2006
[13] Juan L, Bart A, Van Hassel G. Progress towards the demonstration of an advanced OTM Oxy-fuel Boiler. 30th International Coal Conference, Clearwater, FL, 2005
[14] McKee B. Solutions for the 21st century; Zero emissions technologies for fossil fuels. Technology Status Report, International Energy Agency (IEA), Paris, France, 2008
[15] Figueroa J, Fout T, Plasynski S, and McIlvried H. Advances in CO_2 capture technology -The U.S. department of energy's carbon sequestration program, International Journal of Greenhouse Gas Control. 2007, 4: 430-443
[16] Buhre B, Elliott L, Sheng C, et al. Oxy-fuel combustion technology for coal-fired power generation. Progress in Energy and Combustion Science. 2005, 31: 283–307
[17] Zhaohui Y, Zeng Y. High-temperature sorption process for air separation and oxygen removal. Industrial & Engineering Chemistry Research. 2002, 41: 2775-2784
[18] Zhaohui Y. High temperature oxygen sorption process for air separation and oxygen removal: [Doctor Dissertation]. US: Cincinnati University, 2002
[19] Qing Y. Carbon dioxide interaction with perovskite-type oxides and their applications for oxygen separation:[ Doctor Dissertation]. US: Arizona State University, 2005
[20] Karppinen M, Yamauchi H, Otani S. et al. Oxygen nonstoichiometry in YBaCo_(0.4)O_(7+δ): large low-temperature oxygen absorption/desorption capability. Chemistry of Materials. 2006, 18: 490-494
[21] Haoshan H, Jinghua C, Changqing C, et al. Oxygen adsorption properties of YBaCo_(0.4)O_(7+δ)-type compounds. Solid State Ionics. 2006, 177:631-637
[22] Yongxian Z, Divyanshu R, Tamhankar et al. Oxy-fuel combustion process. US Patent. 0138747A1, 2003-07-24
[23] Divyanshu A, Krish R Krishnamurthy, Michael L. Development of a high temperature oxygen generation process and its application to oxy-combustion power plants with carbon dioxide capture. 2006
[24]张腾,李振山,蔡宁生,利用钙钛矿氧化物制取O_2-CO_2混合气体的实验研究,工程热物理学报. 2008, 29: 1591-1594
[25] Guerrieri, Salvatore A. Process for producing high purity oxygen by chemical means. US Patent, 3310381, 1967-12-03
[26] Tobias M, Anders L, Henrik L, Chemical-loopimg with oxygen uncoupling for combustion of solid fuels. International Journal of Greenhouse Gas Control. 2009, 3: 11-19
[27] Kent N Hutchings, Merrill W, Paul A Larsen, Raymond A Cutler. Kinetic and thermodynamic considerations for oxygen absorption/desorption using cobalt oxide. Solid State Ionics. 2005, 177: 45-51
[28] Joseph T Mullhaupt,. Process and composition for separation of oxygen from air using Pr-Ce as the carrier. US Patent 3980763, 1976-09-14
[29] Joseph T Mullhaupt, Tonawanda and Silviu A. Process and composition from air using strontium oxide-peroxide as the carrier. US Patent 3579292, 1971-05-18
[30] Zhenshan L, Teng Z, and Ningsheng C, Experimental study of O_2-CO_2 production for the oxyfuel combustion using a Co-Based oxygen carrier, Industrial & Engineering Chemistry Research. 2008, 47: 7147-7153
[31] Zebao R, Jingjing Ding, Yongdan Li ,Y.S. Lin , SrCo_(0.8)Fe_(0.2)O_(3-δ). sorbent for high-temperature production of oxygen-enriched carbon dioxide stream. Fuel. 2009, 89: 1429-143
[32] Alptekin G, Jayaraman A, Dubovik M, Brickner L. Novel air separation sorbents to support Oxy-combustion. International Colloquium on Environmentally Preferred Advanced Power Generation, Newport Beach, CA, 2008
[33] Leion H, Lyngfelt A. and Mattisson T. Effects of steam and CO_2 in the fluidizing gas when using bituminous coal in chemical-looping combustion. Proceedings of The 20th International Conference on Fluidized Bed Combustion, Xian, China, 2009: 608-611
[34] Sander N, Martin A, Hans K. Packed bed reactor technology for chemical-looping combustion. Industrial & Engineering Chemistry Research. 2007, 46: 4212-4220
[35] Behdad Moghtaderi, Application of chemical looping concept for air separation at high temperatures. Energy and Fuel. 2010, 24:190-198
[36] Marcus J. Screening of oxygen-carrier particles based on iron-, manganese-, copper- and nickel oxides for use chemical-looping technologies. G?teborg, Sweden: Chalmers University of Technology, 2007
[37]葛庆仁.气固反应动力学.北京:原子能出版社, 1991
[38]刘黎明,赵海波,郑楚光.化学链燃烧方式中氧载体的研究进展.煤炭转化. 2006, 29: 83-93
[39]伊赫桑?巴伦主编.程乃良,牛四通,徐桂英等译.纯物质热化学数据手册.北京:科学出版社, 2003
[40]史密斯(美).金属氧化物中的缺陷化学.陕西:西安交通大学出版社, 2006
[41]朱开宏等.化学反应工程分析.北京:高等教育出版社, 2002
[42]郭汉贤.应用化工动力学.北京:化学工业出版社, 2003
[43] Castle W. Air separation and liquefaction: recent developments and prospects for the beginning of the new millennium. International Journal of Refrigeration. 2002,25: 158-172
[44] Figueroa J, Fout T, Plasynski S, McIlvried H, Srivastava R. Advances in CO_2 capture technology—The U.S. department of energy's carbon sequestration program. International Journal of Greenhouse Gas Control. 2008, 2: 9-20
[45] Klas A , Filip J. Process evaluation of an 865 MWe lignite fired O_2/CO_2 power plant. Energy Conversion and Management. 2006, 3487–3498
[46] Dirk K, Mark D. Myers. Mineral Commodity Summaries 2008. U.S. Department of the Interior , U.S. Geological Survey. 2008-01-30
[47] Ken S, Suzette M. Kimball, Mineral Commodity Summaries 2009. U.S. Department of the Interior , U.S. Geological Survey. 2009-01-29
[48] Ken S, Marcia K. Mcnutt, Mineral Commodity Summaries 2010. U.S. Department of the Interior , U.S. Geological Survey. 2010-01-26
[2] Simbeck D. CO_2 mitigation economics for existing coal-fired power plants. Proceedings of First National Conference on Carbon Sequestration. Washington. D.C., US, 2001
[3] Andersson K, Birkestad H, Maksinen P, Johnsson F, Str?mberg L, Lyngfeldt A. An 865 MW lignite fired CO_2 free power plant - a technical feasibility study. Proceedings of GHGT6. Kyoto, Japan, 2002
[4] Singh D, Croiset E, Douglas, et al. Techno-economic study of CO_2 capture from an existing coal-fired power plant: MEA scrubbing vs. O_2/CO_2 recycle combustion. Energy Conversion and Management. 2003, 44: 3073-3091
[5]米翠丽.富氧燃煤锅炉设计研究及其技术经济性分析:[博士学位论文].河北:华北电力大学, 2010
[6] Wall T, Jianglong T. Coal fired oxy fuel technology status and progress to deployment. 34th International Technical Conference on Coal Utilization & Fuel Systems. Florida, USA: Coal Technology Association, 2009
[7]张阳,王湛,纪树兰.富氧技术及其应用.北京:化学工业出版社, 2005
[8] http://www.encapco2.org/technoHTOGPC.html
[9] Herzberg G and Jungen C. Rydberg series and ionization potential of the H2 molecule. Journal of Molecular Spectroscopy. 1972, 41:425-486
[10]李杰.新型紧凑结构四塔变压吸附空分制氧装置研究:[硕士学位论文].天津:天津大学化工学院,2003
[11]韩跃斌,王一平,边守军等.变压吸附(PSA)空气分离工艺技术进展.天然气化工. 1999, 24:36-41
[12] Shah M, Hassel B, Christie M, Li J. CO_2 capture by membrane based oxy-fuel boiler. Proceedings of the 2006 Conference on Carbon Capture and Sequestration, Alexandria, VA, 2006
[13] Juan L, Bart A, Van Hassel G. Progress towards the demonstration of an advanced OTM Oxy-fuel Boiler. 30th International Coal Conference, Clearwater, FL, 2005
[14] McKee B. Solutions for the 21st century; Zero emissions technologies for fossil fuels. Technology Status Report, International Energy Agency (IEA), Paris, France, 2008
[15] Figueroa J, Fout T, Plasynski S, and McIlvried H. Advances in CO_2 capture technology -The U.S. department of energy's carbon sequestration program, International Journal of Greenhouse Gas Control. 2007, 4: 430-443
[16] Buhre B, Elliott L, Sheng C, et al. Oxy-fuel combustion technology for coal-fired power generation. Progress in Energy and Combustion Science. 2005, 31: 283–307
[17] Zhaohui Y, Zeng Y. High-temperature sorption process for air separation and oxygen removal. Industrial & Engineering Chemistry Research. 2002, 41: 2775-2784
[18] Zhaohui Y. High temperature oxygen sorption process for air separation and oxygen removal: [Doctor Dissertation]. US: Cincinnati University, 2002
[19] Qing Y. Carbon dioxide interaction with perovskite-type oxides and their applications for oxygen separation:[ Doctor Dissertation]. US: Arizona State University, 2005
[20] Karppinen M, Yamauchi H, Otani S. et al. Oxygen nonstoichiometry in YBaCo_(0.4)O_(7+δ): large low-temperature oxygen absorption/desorption capability. Chemistry of Materials. 2006, 18: 490-494
[21] Haoshan H, Jinghua C, Changqing C, et al. Oxygen adsorption properties of YBaCo_(0.4)O_(7+δ)-type compounds. Solid State Ionics. 2006, 177:631-637
[22] Yongxian Z, Divyanshu R, Tamhankar et al. Oxy-fuel combustion process. US Patent. 0138747A1, 2003-07-24
[23] Divyanshu A, Krish R Krishnamurthy, Michael L. Development of a high temperature oxygen generation process and its application to oxy-combustion power plants with carbon dioxide capture. 2006
[24]张腾,李振山,蔡宁生,利用钙钛矿氧化物制取O_2-CO_2混合气体的实验研究,工程热物理学报. 2008, 29: 1591-1594
[25] Guerrieri, Salvatore A. Process for producing high purity oxygen by chemical means. US Patent, 3310381, 1967-12-03
[26] Tobias M, Anders L, Henrik L, Chemical-loopimg with oxygen uncoupling for combustion of solid fuels. International Journal of Greenhouse Gas Control. 2009, 3: 11-19
[27] Kent N Hutchings, Merrill W, Paul A Larsen, Raymond A Cutler. Kinetic and thermodynamic considerations for oxygen absorption/desorption using cobalt oxide. Solid State Ionics. 2005, 177: 45-51
[28] Joseph T Mullhaupt,. Process and composition for separation of oxygen from air using Pr-Ce as the carrier. US Patent 3980763, 1976-09-14
[29] Joseph T Mullhaupt, Tonawanda and Silviu A. Process and composition from air using strontium oxide-peroxide as the carrier. US Patent 3579292, 1971-05-18
[30] Zhenshan L, Teng Z, and Ningsheng C, Experimental study of O_2-CO_2 production for the oxyfuel combustion using a Co-Based oxygen carrier, Industrial & Engineering Chemistry Research. 2008, 47: 7147-7153
[31] Zebao R, Jingjing Ding, Yongdan Li ,Y.S. Lin , SrCo_(0.8)Fe_(0.2)O_(3-δ). sorbent for high-temperature production of oxygen-enriched carbon dioxide stream. Fuel. 2009, 89: 1429-143
[32] Alptekin G, Jayaraman A, Dubovik M, Brickner L. Novel air separation sorbents to support Oxy-combustion. International Colloquium on Environmentally Preferred Advanced Power Generation, Newport Beach, CA, 2008
[33] Leion H, Lyngfelt A. and Mattisson T. Effects of steam and CO_2 in the fluidizing gas when using bituminous coal in chemical-looping combustion. Proceedings of The 20th International Conference on Fluidized Bed Combustion, Xian, China, 2009: 608-611
[34] Sander N, Martin A, Hans K. Packed bed reactor technology for chemical-looping combustion. Industrial & Engineering Chemistry Research. 2007, 46: 4212-4220
[35] Behdad Moghtaderi, Application of chemical looping concept for air separation at high temperatures. Energy and Fuel. 2010, 24:190-198
[36] Marcus J. Screening of oxygen-carrier particles based on iron-, manganese-, copper- and nickel oxides for use chemical-looping technologies. G?teborg, Sweden: Chalmers University of Technology, 2007
[37]葛庆仁.气固反应动力学.北京:原子能出版社, 1991
[38]刘黎明,赵海波,郑楚光.化学链燃烧方式中氧载体的研究进展.煤炭转化. 2006, 29: 83-93
[39]伊赫桑?巴伦主编.程乃良,牛四通,徐桂英等译.纯物质热化学数据手册.北京:科学出版社, 2003
[40]史密斯(美).金属氧化物中的缺陷化学.陕西:西安交通大学出版社, 2006
[41]朱开宏等.化学反应工程分析.北京:高等教育出版社, 2002
[42]郭汉贤.应用化工动力学.北京:化学工业出版社, 2003
[43] Castle W. Air separation and liquefaction: recent developments and prospects for the beginning of the new millennium. International Journal of Refrigeration. 2002,25: 158-172
[44] Figueroa J, Fout T, Plasynski S, McIlvried H, Srivastava R. Advances in CO_2 capture technology—The U.S. department of energy's carbon sequestration program. International Journal of Greenhouse Gas Control. 2008, 2: 9-20
[45] Klas A , Filip J. Process evaluation of an 865 MWe lignite fired O_2/CO_2 power plant. Energy Conversion and Management. 2006, 3487–3498
[46] Dirk K, Mark D. Myers. Mineral Commodity Summaries 2008. U.S. Department of the Interior , U.S. Geological Survey. 2008-01-30
[47] Ken S, Suzette M. Kimball, Mineral Commodity Summaries 2009. U.S. Department of the Interior , U.S. Geological Survey. 2009-01-29
[48] Ken S, Marcia K. Mcnutt, Mineral Commodity Summaries 2010. U.S. Department of the Interior , U.S. Geological Survey. 2010-01-26