A modular formulation of model predictive controller is proposed by this invention (400). The modular formulation offers a robust model predictive controller with unified method of tuning. Explicit use of material and energy balance provides stable and robust performance (412). Use of economic based tuning offers a unified tuning method (411). The unified tuning method establishes consistency of control actions resulting from the steady state optimization and the dynamic control (400). Further, a method for formulating and tuning integrated optimization and control using multiple modular model predictive controllers is presented in this invention (100). The method incorporates a direct and explicit method of integration of a number of modular model predictive controllers. The integration of the modular controllers is achieved seamlessly without requiring any further tuning adjustments (200). The resulting integrated system of multiple modular predictive controllers performs robustly, permitting each of the modular model predictive controllers to perform its role in the context of the state of operation of rest of the system. The proposed integration can be made to include lower level modular controllers or at same level controllers or both (300). (FIG. - 1)