Modeling and optimization of a fluidized catalytic cracking process under full and partial combustion modes

Abstract A process optimization system, which consists of a steady-state process model, a model parameter estimator and a process optimizer for a fluidized catalytic cracking (FCC) process under full and partial combustion modes, is presented in this paper. First, mathematical modeling was carried out for the reactor, regenerator, main-fractionator, and most of auxiliary units including the feed pre-heater, catalyst cooler, air blower, wet gas compressor, stack gas expander, boilers, and valves. Then, the resulting steady-state model was utilized to develop the model parameter estimator and the process optimizer both of which adopt a successive quadratic programming algorithm to efficiently locate the optimum solutions. The parameter estimator can estimate up to 52 model parameters in order to validate the process model by reducing process–model mismatch. The process optimizer maximizes the economic objective function defined as the difference between the total value of products and the cost of feedstock and utility under 30 operating constraints. The developed optimization system was applied to several optimization cases to maximize the economic profit of the FCC process operated in the full and partial combustion modes and the optimization results were extensively compared and analyzed between the combustion modes. It is expected that the proposed steady-state model, parameter estimation and optimization methods can be utilized to optimize and design modem-type FCC processes under full and partial combustion modes.

[1]  Chang-Bock Chung,et al.  Dynamic modeling and simulation of a fluidized catalytic cracking process. Part I : Process modeling , 2001 .

[2]  Chang-Bock Chung,et al.  Multivariable Control of a Fluidized Catalytic Cracking Process under Full and Partial Combustion Modes , 2002 .

[3]  Carl de Boor,et al.  A Practical Guide to Splines , 1978, Applied Mathematical Sciences.

[4]  Paul B. Weisz,et al.  Combustion of carbonaceous deposits within porous catalyst particles: II. Intrinsic burning rate , 1966 .

[5]  Robert Charles Ellis.  Supervisory optimization of a fluidized catalytic cracking unit , 1996 .

[6]  Paul B. Weisz.  Combustion of carbonaceous deposits within porous catalyst particles: III. The CO2CO product ratio , 1966 .

[7]  Robert A. Meyers,et al.  Handbook of Petroleum Refining Processes , 2003 .

[8]  O. Levenspiel,et al.  Fluidization engineering, 2nd edition , 1991 .

[9]  Koichiro Kusunoki,et al.  THE BURNING RATE OF COKE DEPOSITED ON ZEOLITE CATALYST , 1975 .

[10]  Chang-Bock Chung,et al.  Dynamic modeling and simulation of a fluidized catalytic cracking process. Part II: Property estimation and simulation , 2001 .

[11]  P. Gill,et al.  Fortran package for nonlinear programming. User's Guide for NPSOL (Version 4. 0) , 1986 .

[12]  Chang-Bock Chung,et al.  Modeling of a fluidized catalytic cracking process , 2000 .

[13]  David M. Young,et al.  A historical overview of iterative methods , 1989 .

[14]  E. T. Habib,et al.  ADVANCES IN FLUID CATALYTIC CRACKING , 2002 .

[15]  Xuan Li,et al.  Modeling and Optimization of a Model IV Fluidized Catalytic Cracking Unit , 1998 .

[16]  John J. McKetta,et al.  Encyclopedia of Chemical Processing and Design , 1976 .

[17]  Stig Strand,et al.  Real-time optimization of a cat cracker unit , 1997 .

[18]  Singiresu S. Rao.  Engineering Optimization : Theory and Practice , 2010 .

[19]  Zhifa Sun,et al.  Numerical simulation of flow in an array of in-line blunt boards: mass transfer and flow patterns , 2001 .

[20]  Sigurd Skogestad,et al.  Procedure for regulatory control structure selection with application to the FCC process , 1993 .

[21]  Sunwon Park,et al.  Nonlinear static composition estimator for distillation columns using open equation-based nonlinear programming , 1997 .

[22]  W. Licht,et al.  Air pollution control engineering: Basic calculations for particulate collection , 1980 .

[23]  S. E. Voltz,et al.  A lumping and reaction scheme for catalytic cracking , 1976 .