In this paper the problem−div(a(x,y)∇u)=f with Dirichlet boundary conditions on a square is solved iteratively with high accuracy for u and∇u using a new scheme called“hermitian box-scheme”.The design of the scheme ...In this paper the problem−div(a(x,y)∇u)=f with Dirichlet boundary conditions on a square is solved iteratively with high accuracy for u and∇u using a new scheme called“hermitian box-scheme”.The design of the scheme is based on a“hermitian box”,combining the approximation of the gradient by the fourth order hermitian derivative,with a conservative discrete formulation on boxes of length 2h.The iterative technique is based on the repeated solution by a fast direct method of a discrete Poisson equation on a uniform rectangular mesh.The problem is suitably scaled before iteration.The numerical results obtained show the efficiency of the numerical scheme.This work is the extension to strongly elliptic problems of the hermitian box-scheme presented by Abbas and Croisille(J.Sci.Comput.,49(2011),pp.239–267).展开更多
This paper presents an algorithm that combines model predictive control(MPC)with MINLP optimization and demonstrates its application for coal-fired power plants retrofitted with solvent based post-combustion CO_(2) ca...This paper presents an algorithm that combines model predictive control(MPC)with MINLP optimization and demonstrates its application for coal-fired power plants retrofitted with solvent based post-combustion CO_(2) capture(PCC)plant.The objective function of the optimization algorithm works at a primary level to maximize plant economic revenue while considering an optimal carbon capture profile.At a secondary level,the MPC algorithm is used to control the performance of the PCC plant.Two techno-economic scenarios based on fixed(capture rate is constant)and flexible(capture rate is variable)operation modes are developed using actual electricity prices(2011)with fixed carbon prices($AUD 5,25,50/tonne-CO_(2))for 24 h periods.Results show that fixed operation mode can bring about a ratio of net operating revenue deficit at an average of 6%against the superior flexible operation mode.展开更多
文摘In this paper the problem−div(a(x,y)∇u)=f with Dirichlet boundary conditions on a square is solved iteratively with high accuracy for u and∇u using a new scheme called“hermitian box-scheme”.The design of the scheme is based on a“hermitian box”,combining the approximation of the gradient by the fourth order hermitian derivative,with a conservative discrete formulation on boxes of length 2h.The iterative technique is based on the repeated solution by a fast direct method of a discrete Poisson equation on a uniform rectangular mesh.The problem is suitably scaled before iteration.The numerical results obtained show the efficiency of the numerical scheme.This work is the extension to strongly elliptic problems of the hermitian box-scheme presented by Abbas and Croisille(J.Sci.Comput.,49(2011),pp.239–267).
基金The authors wish to acknowledge financial assistance provided through Australian National Low Emissions Coal Research and Development(ANLEC R&D).ANLEC R&D is supported by Australian Coal Association Low Emissions Technology Limited and the Australian Government through the Clean Energy Initiative.
文摘This paper presents an algorithm that combines model predictive control(MPC)with MINLP optimization and demonstrates its application for coal-fired power plants retrofitted with solvent based post-combustion CO_(2) capture(PCC)plant.The objective function of the optimization algorithm works at a primary level to maximize plant economic revenue while considering an optimal carbon capture profile.At a secondary level,the MPC algorithm is used to control the performance of the PCC plant.Two techno-economic scenarios based on fixed(capture rate is constant)and flexible(capture rate is variable)operation modes are developed using actual electricity prices(2011)with fixed carbon prices($AUD 5,25,50/tonne-CO_(2))for 24 h periods.Results show that fixed operation mode can bring about a ratio of net operating revenue deficit at an average of 6%against the superior flexible operation mode.
