Plantwide control and operating strategy for air separation unit in oxy-combustion power plants

Abstract To ensure that air separation unit can bear high ramp rate and flexible operations when integrated into oxy-combustion power plant, this paper focuses on the investigations of plantwide control design and operating strategy for double-column air separation unit without or with liquid oxygen storage drum through dynamic simulation. It is found that three air separation unit types (normal, oversize, and downsize) with the proposed control structure configured with logic control loops (strategies 1, 2, and 3) can achieve 5%/min of high ramp rate and flexible operations such as peak and off-peak or/and energy storage. Compared between the latter two logical controls, strategy 2 would be better because its oxygen product qualities can be maintained closer to their targets. Three integrated patterns between air separation unit and oxy-combustion boiler are proposed to improve operating flexibility, among which oversize case would be more suitable for oxy-combustion power plant since its energy saving (20.33 MW) is larger and operating strategy is more flexible than those in downsize (10.76 MW) and normal cases. Process control for flexible operations would be an opportunity for engineering, and comprehensive dynamic model with specified control system provides possibility to integrate air separation unit with full-train oxy-combustion power plants.

[1]  Chao Fu,et al.  Integrating the Compression Heat in Oxy-combustion Power Plants with CO2 Capture , 2012 .

[2]  William L. Luyben.  Plantwide Dynamic Simulators in Chemical Processing and Control , 2002 .

[3]  Oxy-combustion : an ASU integration option and improved operation flexibility , 2013 .

[4]  Sebastian Engell,et al.  A case study for control structure selection: air separation plant , 2000 .

[5]  Chuguang Zheng,et al.  Exergy Analysis of a 600 MWe Oxy-combustion Pulverized-Coal-Fired Power Plant , 2011 .

[6]  Jean-Pierre Tranier,et al.  Oxycombustion for Carbon Capture on Coal Power Plants and Industrial Processes: Advantages, Innovative Solutions and Key Projects☆ , 2013 .

[7]  Stephen E. Zitney,et al.  Dynamic Maximization of Oxygen Yield in an Elevated-Pressure Air Separation Unit using Multiple Model Predictive Control , 2013 .

[8]  L. V. van der Ham,et al.  Improving the exergy efficiency of a cryogenic air separation unit as part of an integrated gasification combined cycle , 2012 .

[9]  Sigurd Skogestad,et al.  Control structure design for complete chemical plants , 2004, Comput. Chem. Eng..

[10]  Chao Fu,et al.  Recuperative vapor recompression heat pumps in cryogenic air separation processes , 2013 .

[11]  William L. Luyben,et al.  Plantwide control design procedure , 1997 .

[12]  A. Smith,et al.  A review of air separation technologies and their integration with energy conversion processes , 2001 .

[13]  B. Wayne Bequette,et al.  Design and Control of an Elevated-Pressure Air Separations Unit for IGCC Power Plants in a Process Simulator Environment , 2013 .

[14]  Jay H. Lee,et al.  Control Structure Selection for the Elevated-Pressure Air Separation Unit in an IGCC Power Plant: Self-Optimizing Control Structure for Economical Operation , 2014 .

[15]  Chuguang Zheng,et al.  Dynamic modeling and control for pulverized-coal-fired oxy-combustion boiler island , 2014 .

[16]  Debangsu Bhattacharyya,et al.  Optimal design and integration of an air separation unit (ASU) for an integrated gasification combined cycle (IGCC) power plant with CO2 capture , 2011 .

[17]  L. V. van der Ham,et al.  Exergy analysis of two cryogenic air separation processes , 2010 .

[18]  Michela Vellini,et al.  Oxygen production technologies for IGCC power plants with CO2 capture , 2011 .

[19]  Zuhua Xu,et al.  Automatic load change system of cryogenic air separation process , 2011 .

[20]  Chuguang Zheng,et al.  Comprehensive investigation of process characteristics for oxy-steam combustion power plants , 2015 .

[21]  P. A. Jensen,et al.  Oxy-fuel combustion of solid fuels , 2010 .

[22]  Rene Cornelissen,et al.  Exergy analysis of cryogenic air separation , 1998 .

[23]  David R. Vinson,et al.  Air separation control technology , 2006, Comput. Chem. Eng..

[24]  Dimitri Goloubeva,et al.  Integration of ASU in process of power generation , 2013 .

[25]  Xun Li,et al.  Peak and off-peak operations of the air separation unit in oxy-coal combustion power generation systems , 2013 .

[26]  Chuguang Zheng,et al.  Dynamic simulation for mode switching strategy in a conceptual 600 MWe oxy-combustion pulverized-coal-fired boiler , 2014 .

[27]  Jean-Pierre Tranier,et al.  Air separation, flue gas compression and purification units for oxy-coal combustion systems , 2009 .

[28]  Jorge Anibal Mandler.  Modelling for control analysis and design in complex industrial separation and liquefaction processes , 2000 .

[29]  Brian Roffel,et al.  First principles dynamic modeling and multivariable control of a cryogenic distillation process , 2000 .

[30]  Vince White,et al.  Oxygen supply for oxyfuel CO2 capture , 2011 .

[31]  Chao Fu,et al.  Using exergy analysis to reduce power consumption in air separation units for oxy-combustion processes , 2012 .

[32]  Chuguang Zheng,et al.  Optimization and control for CO2 compression and purification unit in oxy-combustion power plants , 2015 .