$*************************************************************
$ Catalyst Mixing for Packed Bed Reactor
$ L. T. Biegler and I. B. Tjoa
$
$ CACHE Process Design Case Studies
$ M. Morari and I.E. Grossmann
$
$ Optimal Solution:  -0.014397
$*************************************************************

DECLARATION {{
  XVAR {j,k1,k2};

  XLBD {0,-5,-5};
  XSTP {1, 0, 0};
  XUBD {1, 5, 5};

  ZVAR {za,zb,U};
  ISPE {za,zb};
  ZINC {1,0,0};
  TIME {0,0.4};
}}

MODEL {{
  MIN:  -j;
  dae1: za' =e= U*(10*zb - za);
  dae2: zb' =e= U*(za - 10*zb) - (1-U)*zb;
  dae3: U =e= k1 + k2*t;
  obj1[1]: j =e= 1 - za - zb;
  con1[0]: U =l= 1;
  con1[0]: U =g= 0;
  con1[1]: U =l= 1;
  con1[1]: U =g= 0;
}}