[ Eq(Derivative(x1, t), ((-1)*k14*Piecewise((k1/(111/10), Eq(k13, 1)), (k1/(41/5), True))*x7*x1 + 1*k14*k1*x2 + 1*k14*k7*x2 + (-1)*k14*k5*x1 + 1*k14*k6)/k14),
  Eq(Derivative(x2, t), (1*k14*Piecewise((k1/(111/10), Eq(k13, 1)), (k1/(41/5), True))*x7*x1 + (-1)*k14*k1*x2 + (-1)*k14*k8*x2)/k14),
  Eq(Derivative(x3, t), (1*k14*k5*x1 + (-1)*k14*Piecewise((Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))/1000, Eq(k13, 1)), (Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))/3000, True))*x5*x3 + 1*k14*Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))*x4 + (-1)*k14*k10*x3)/k14),
  Eq(Derivative(x4, t), (1*k14*k8*x2 + 1*k14*Piecewise((Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))/1000, Eq(k13, 1)), (Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))/3000, True))*x5*x3 + (-1)*k14*Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))*x4 + (-1)*k14*k10*x4)/k14),
  Eq(Derivative(x5, t), ((-1)*k14*(Piecewise((k1/(111/10), Eq(k13, 1)), (k1/(41/5), True))*x5*x3 - Piecewise((k1*8, Eq(k13, 1)), (k1*5, True))*x4)/(k11*k12) + (-1)*k14*k9*x5)/k14),
  Eq(Derivative(x6, t), 1*k14*k10*x4/k14),
  Eq(Derivative(x7, t), (-1)*k14*(Piecewise((k1/(111/10), Eq(k13, 1)), (k1/(41/5), True))*x7*x1 - k1*x2 - k9*x5*k11*k12)*x8/k12/k14),
  Eq(Derivative(x8, t), Piecewise(((600*x2/(250 + x2) - 200)*1000, Gt(600*x2/(250 + x2) - 200, 0)), (0, True))) ]